[RFC PATCH v4 08/28] cli: Add Busybox upstream hush.c file

Francis Laniel francis.laniel at amarulasolutions.com
Fri Jun 17 00:31:38 CEST 2022


This commit adds new file cli_hush_2021_upstream.c, it is a copy of Busybox hush
file it was of time to Busybox commit 37460f5da.

Signed-off-by: Francis Laniel <francis.laniel at amarulasolutions.com>
Reviewed-by: Simon Glass <sjg at chromium.org>
---
 common/cli_hush_upstream.c | 12162 +++++++++++++++++++++++++++++++++++
 1 file changed, 12162 insertions(+)
 create mode 100644 common/cli_hush_upstream.c

diff --git a/common/cli_hush_upstream.c b/common/cli_hush_upstream.c
new file mode 100644
index 0000000000..c970d9097e
--- /dev/null
+++ b/common/cli_hush_upstream.c
@@ -0,0 +1,12162 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * A prototype Bourne shell grammar parser.
+ * Intended to follow the original Thompson and Ritchie
+ * "small and simple is beautiful" philosophy, which
+ * incidentally is a good match to today's BusyBox.
+ *
+ * Copyright (C) 2000,2001  Larry Doolittle <larry at doolittle.boa.org>
+ * Copyright (C) 2008,2009  Denys Vlasenko <vda.linux at googlemail.com>
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ *
+ * Credits:
+ *      The parser routines proper are all original material, first
+ *      written Dec 2000 and Jan 2001 by Larry Doolittle.  The
+ *      execution engine, the builtins, and much of the underlying
+ *      support has been adapted from busybox-0.49pre's lash, which is
+ *      Copyright (C) 1999-2004 by Erik Andersen <andersen at codepoet.org>
+ *      written by Erik Andersen <andersen at codepoet.org>.  That, in turn,
+ *      is based in part on ladsh.c, by Michael K. Johnson and Erik W.
+ *      Troan, which they placed in the public domain.  I don't know
+ *      how much of the Johnson/Troan code has survived the repeated
+ *      rewrites.
+ *
+ * Other credits:
+ *      o_addchr derived from similar w_addchar function in glibc-2.2.
+ *      parse_redirect, redirect_opt_num, and big chunks of main
+ *      and many builtins derived from contributions by Erik Andersen.
+ *      Miscellaneous bugfixes from Matt Kraai.
+ *
+ * There are two big (and related) architecture differences between
+ * this parser and the lash parser.  One is that this version is
+ * actually designed from the ground up to understand nearly all
+ * of the Bourne grammar.  The second, consequential change is that
+ * the parser and input reader have been turned inside out.  Now,
+ * the parser is in control, and asks for input as needed.  The old
+ * way had the input reader in control, and it asked for parsing to
+ * take place as needed.  The new way makes it much easier to properly
+ * handle the recursion implicit in the various substitutions, especially
+ * across continuation lines.
+ *
+ * TODOs:
+ *      grep for "TODO" and fix (some of them are easy)
+ *      make complex ${var%...} constructs support optional
+ *      make here documents optional
+ *      special variables (done: PWD, PPID, RANDOM)
+ *      follow IFS rules more precisely, including update semantics
+ *      tilde expansion
+ *      aliases
+ *      "command" missing features:
+ *          command -p CMD: run CMD using default $PATH
+ *              (can use this to override standalone shell as well?)
+ *          command BLTIN: disables special-ness (e.g. errors do not abort)
+ *          command -V CMD1 CMD2 CMD3 (multiple args) (not in standard)
+ *      builtins mandated by standards we don't support:
+ *          [un]alias, fc:
+ *          fc -l[nr] [BEG] [END]: list range of commands in history
+ *          fc [-e EDITOR] [BEG] [END]: edit/rerun range of commands
+ *          fc -s [PAT=REP] [CMD]: rerun CMD, replacing PAT with REP
+ *
+ * Bash compat TODO:
+ *      redirection of stdout+stderr: &> and >&
+ *      reserved words: function select
+ *      advanced test: [[ ]]
+ *      process substitution: <(list) and >(list)
+ *      let EXPR [EXPR...]
+ *          Each EXPR is an arithmetic expression (ARITHMETIC EVALUATION)
+ *          If the last arg evaluates to 0, let returns 1; 0 otherwise.
+ *          NB: let `echo 'a=a + 1'` - error (IOW: multi-word expansion is used)
+ *      ((EXPR))
+ *          The EXPR is evaluated according to ARITHMETIC EVALUATION.
+ *          This is exactly equivalent to let "EXPR".
+ *      $[EXPR]: synonym for $((EXPR))
+ *      indirect expansion: ${!VAR}
+ *      substring op on @: ${@:n:m}
+ *
+ * Won't do:
+ *      Some builtins mandated by standards:
+ *          newgrp [GRP]: not a builtin in bash but a suid binary
+ *              which spawns a new shell with new group ID
+ *
+ * Status of [[ support:
+ * [[ args ]] are CMD_SINGLEWORD_NOGLOB:
+ *   v='a b'; [[ $v = 'a b' ]]; echo 0:$?
+ *   [[ /bin/n* ]]; echo 0:$?
+ *   = is glob match operator, not equality operator: STR = GLOB
+ *   == same as =
+ *   =~ is regex match operator: STR =~ REGEX
+ * TODO:
+ * quoting needs to be considered (-f is an operator, "-f" and ""-f are not; etc)
+ * in word = GLOB, quoting should be significant on char-by-char basis: a*cd"*"
+ */
+//config:config HUSH
+//config:	bool "hush (68 kb)"
+//config:	default y
+//config:	select SHELL_HUSH
+//config:	help
+//config:	hush is a small shell. It handles the normal flow control
+//config:	constructs such as if/then/elif/else/fi, for/in/do/done, while loops,
+//config:	case/esac. Redirections, here documents, $((arithmetic))
+//config:	and functions are supported.
+//config:
+//config:	It will compile and work on no-mmu systems.
+//config:
+//config:	It does not handle select, aliases, tilde expansion,
+//config:	&>file and >&file redirection of stdout+stderr.
+//config:
+// This option is visible (has a description) to make it possible to select
+// a "scripted" applet (such as NOLOGIN) but avoid selecting any shells:
+//config:config SHELL_HUSH
+//config:	bool "Internal shell for embedded script support"
+//config:	default n
+//config:
+//config:# hush options
+//config:# It's only needed to get "nice" menuconfig indenting.
+//config:if SHELL_HUSH || HUSH || SH_IS_HUSH || BASH_IS_HUSH
+//config:
+//config:config HUSH_BASH_COMPAT
+//config:	bool "bash-compatible extensions"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_BRACE_EXPANSION
+//config:	bool "Brace expansion"
+//config:	default y
+//config:	depends on HUSH_BASH_COMPAT
+//config:	help
+//config:	Enable {abc,def} extension.
+//config:
+//config:config HUSH_BASH_SOURCE_CURDIR
+//config:	bool "'source' and '.' builtins search current directory after $PATH"
+//config:	default n   # do not encourage non-standard behavior
+//config:	depends on HUSH_BASH_COMPAT
+//config:	help
+//config:	This is not compliant with standards. Avoid if possible.
+//config:
+//config:config HUSH_LINENO_VAR
+//config:	bool "$LINENO variable (bashism)"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_INTERACTIVE
+//config:	bool "Interactive mode"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:	help
+//config:	Enable interactive mode (prompt and command editing).
+//config:	Without this, hush simply reads and executes commands
+//config:	from stdin just like a shell script from a file.
+//config:	No prompt, no PS1/PS2 magic shell variables.
+//config:
+//config:config HUSH_SAVEHISTORY
+//config:	bool "Save command history to .hush_history"
+//config:	default y
+//config:	depends on HUSH_INTERACTIVE && FEATURE_EDITING_SAVEHISTORY
+//config:
+//config:config HUSH_JOB
+//config:	bool "Job control"
+//config:	default y
+//config:	depends on HUSH_INTERACTIVE
+//config:	help
+//config:	Enable job control: Ctrl-Z backgrounds, Ctrl-C interrupts current
+//config:	command (not entire shell), fg/bg builtins work. Without this option,
+//config:	"cmd &" still works by simply spawning a process and immediately
+//config:	prompting for next command (or executing next command in a script),
+//config:	but no separate process group is formed.
+//config:
+//config:config HUSH_TICK
+//config:	bool "Support command substitution"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:	help
+//config:	Enable `command` and $(command).
+//config:
+//config:config HUSH_IF
+//config:	bool "Support if/then/elif/else/fi"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_LOOPS
+//config:	bool "Support for, while and until loops"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_CASE
+//config:	bool "Support case ... esac statement"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:	help
+//config:	Enable case ... esac statement. +400 bytes.
+//config:
+//config:config HUSH_FUNCTIONS
+//config:	bool "Support funcname() { commands; } syntax"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:	help
+//config:	Enable support for shell functions. +800 bytes.
+//config:
+//config:config HUSH_LOCAL
+//config:	bool "local builtin"
+//config:	default y
+//config:	depends on HUSH_FUNCTIONS
+//config:	help
+//config:	Enable support for local variables in functions.
+//config:
+//config:config HUSH_RANDOM_SUPPORT
+//config:	bool "Pseudorandom generator and $RANDOM variable"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:	help
+//config:	Enable pseudorandom generator and dynamic variable "$RANDOM".
+//config:	Each read of "$RANDOM" will generate a new pseudorandom value.
+//config:
+//config:config HUSH_MODE_X
+//config:	bool "Support 'hush -x' option and 'set -x' command"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:	help
+//config:	This instructs hush to print commands before execution.
+//config:	Adds ~300 bytes.
+//config:
+//config:config HUSH_ECHO
+//config:	bool "echo builtin"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_PRINTF
+//config:	bool "printf builtin"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_TEST
+//config:	bool "test builtin"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_HELP
+//config:	bool "help builtin"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_EXPORT
+//config:	bool "export builtin"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_EXPORT_N
+//config:	bool "Support 'export -n' option"
+//config:	default y
+//config:	depends on HUSH_EXPORT
+//config:	help
+//config:	export -n unexports variables. It is a bash extension.
+//config:
+//config:config HUSH_READONLY
+//config:	bool "readonly builtin"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:	help
+//config:	Enable support for read-only variables.
+//config:
+//config:config HUSH_KILL
+//config:	bool "kill builtin (supports kill %jobspec)"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_WAIT
+//config:	bool "wait builtin"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_COMMAND
+//config:	bool "command builtin"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_TRAP
+//config:	bool "trap builtin"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_TYPE
+//config:	bool "type builtin"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_TIMES
+//config:	bool "times builtin"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_READ
+//config:	bool "read builtin"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_SET
+//config:	bool "set builtin"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_UNSET
+//config:	bool "unset builtin"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_ULIMIT
+//config:	bool "ulimit builtin"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_UMASK
+//config:	bool "umask builtin"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_GETOPTS
+//config:	bool "getopts builtin"
+//config:	default y
+//config:	depends on SHELL_HUSH
+//config:
+//config:config HUSH_MEMLEAK
+//config:	bool "memleak builtin (debugging)"
+//config:	default n
+//config:	depends on SHELL_HUSH
+//config:
+//config:endif # hush options
+
+//applet:IF_HUSH(APPLET(hush, BB_DIR_BIN, BB_SUID_DROP))
+//                       APPLET_ODDNAME:name  main  location    suid_type     help
+//applet:IF_SH_IS_HUSH(  APPLET_ODDNAME(sh,   hush, BB_DIR_BIN, BB_SUID_DROP, hush))
+//applet:IF_BASH_IS_HUSH(APPLET_ODDNAME(bash, hush, BB_DIR_BIN, BB_SUID_DROP, hush))
+
+//kbuild:lib-$(CONFIG_SHELL_HUSH) += hush.o match.o shell_common.o
+//kbuild:lib-$(CONFIG_HUSH_RANDOM_SUPPORT) += random.o
+
+/* -i (interactive) is also accepted,
+ * but does nothing, therefore not shown in help.
+ * NOMMU-specific options are not meant to be used by users,
+ * therefore we don't show them either.
+ */
+//usage:#define hush_trivial_usage
+//usage:	"[-enxl] [-c 'SCRIPT' [ARG0 ARGS] | FILE [ARGS] | -s [ARGS]]"
+//usage:#define hush_full_usage "\n\n"
+//usage:	"Unix shell interpreter"
+
+#if !(defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) \
+	|| defined(__APPLE__) \
+    )
+# include <malloc.h>   /* for malloc_trim */
+#endif
+#include <glob.h>
+/* #include <dmalloc.h> */
+#if ENABLE_HUSH_CASE
+# include <fnmatch.h>
+#endif
+#include <sys/times.h>
+#include <sys/utsname.h> /* for setting $HOSTNAME */
+
+#include "busybox.h"  /* for APPLET_IS_NOFORK/NOEXEC */
+#include "unicode.h"
+#include "shell_common.h"
+#include "math.h"
+#include "match.h"
+#if ENABLE_HUSH_RANDOM_SUPPORT
+# include "random.h"
+#else
+# define CLEAR_RANDOM_T(rnd) ((void)0)
+#endif
+#ifndef O_CLOEXEC
+# define O_CLOEXEC 0
+#endif
+#ifndef F_DUPFD_CLOEXEC
+# define F_DUPFD_CLOEXEC F_DUPFD
+#endif
+
+#if ENABLE_FEATURE_SH_EMBEDDED_SCRIPTS && !(ENABLE_ASH || ENABLE_SH_IS_ASH || ENABLE_BASH_IS_ASH)
+# include "embedded_scripts.h"
+#else
+# define NUM_SCRIPTS 0
+#endif
+
+/* So far, all bash compat is controlled by one config option */
+/* Separate defines document which part of code implements what */
+#define BASH_PATTERN_SUBST ENABLE_HUSH_BASH_COMPAT
+#define BASH_SUBSTR        ENABLE_HUSH_BASH_COMPAT
+#define BASH_SOURCE        ENABLE_HUSH_BASH_COMPAT
+#define BASH_DOLLAR_SQUOTE ENABLE_HUSH_BASH_COMPAT
+#define BASH_HOSTNAME_VAR  ENABLE_HUSH_BASH_COMPAT
+#define BASH_EPOCH_VARS    ENABLE_HUSH_BASH_COMPAT
+#define BASH_TEST2         (ENABLE_HUSH_BASH_COMPAT && ENABLE_HUSH_TEST)
+#define BASH_READ_D        ENABLE_HUSH_BASH_COMPAT
+
+
+/* Build knobs */
+#define LEAK_HUNTING 0
+#define BUILD_AS_NOMMU 0
+/* Enable/disable sanity checks. Ok to enable in production,
+ * only adds a bit of bloat. Set to >1 to get non-production level verbosity.
+ * Keeping 1 for now even in released versions.
+ */
+#define HUSH_DEBUG 1
+/* Slightly bigger (+200 bytes), but faster hush.
+ * So far it only enables a trick with counting SIGCHLDs and forks,
+ * which allows us to do fewer waitpid's.
+ * (we can detect a case where neither forks were done nor SIGCHLDs happened
+ * and therefore waitpid will return the same result as last time)
+ */
+#define ENABLE_HUSH_FAST 0
+/* TODO: implement simplified code for users which do not need ${var%...} ops
+ * So far ${var%...} ops are always enabled:
+ */
+#define ENABLE_HUSH_DOLLAR_OPS 1
+
+
+#if BUILD_AS_NOMMU
+# undef BB_MMU
+# undef USE_FOR_NOMMU
+# undef USE_FOR_MMU
+# define BB_MMU 0
+# define USE_FOR_NOMMU(...) __VA_ARGS__
+# define USE_FOR_MMU(...)
+#endif
+
+#include "NUM_APPLETS.h"
+#if NUM_APPLETS == 1
+/* STANDALONE does not make sense, and won't compile */
+# undef CONFIG_FEATURE_SH_STANDALONE
+# undef ENABLE_FEATURE_SH_STANDALONE
+# undef IF_FEATURE_SH_STANDALONE
+# undef IF_NOT_FEATURE_SH_STANDALONE
+# define ENABLE_FEATURE_SH_STANDALONE 0
+# define IF_FEATURE_SH_STANDALONE(...)
+# define IF_NOT_FEATURE_SH_STANDALONE(...) __VA_ARGS__
+#endif
+
+#if !ENABLE_HUSH_INTERACTIVE
+# undef ENABLE_FEATURE_EDITING
+# define ENABLE_FEATURE_EDITING 0
+# undef ENABLE_FEATURE_EDITING_FANCY_PROMPT
+# define ENABLE_FEATURE_EDITING_FANCY_PROMPT 0
+# undef ENABLE_FEATURE_EDITING_SAVE_ON_EXIT
+# define ENABLE_FEATURE_EDITING_SAVE_ON_EXIT 0
+#endif
+
+/* Do we support ANY keywords? */
+#if ENABLE_HUSH_IF || ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
+# define HAS_KEYWORDS 1
+# define IF_HAS_KEYWORDS(...) __VA_ARGS__
+# define IF_HAS_NO_KEYWORDS(...)
+#else
+# define HAS_KEYWORDS 0
+# define IF_HAS_KEYWORDS(...)
+# define IF_HAS_NO_KEYWORDS(...) __VA_ARGS__
+#endif
+
+/* If you comment out one of these below, it will be #defined later
+ * to perform debug printfs to stderr: */
+#define debug_printf(...)         do {} while (0)
+/* Finer-grained debug switches */
+#define debug_printf_parse(...)   do {} while (0)
+#define debug_printf_heredoc(...) do {} while (0)
+#define debug_print_tree(a, b)    do {} while (0)
+#define debug_printf_exec(...)    do {} while (0)
+#define debug_printf_env(...)     do {} while (0)
+#define debug_printf_jobs(...)    do {} while (0)
+#define debug_printf_expand(...)  do {} while (0)
+#define debug_printf_varexp(...)  do {} while (0)
+#define debug_printf_glob(...)    do {} while (0)
+#define debug_printf_redir(...)   do {} while (0)
+#define debug_printf_list(...)    do {} while (0)
+#define debug_printf_subst(...)   do {} while (0)
+#define debug_printf_prompt(...)  do {} while (0)
+#define debug_printf_clean(...)   do {} while (0)
+
+#define ERR_PTR ((void*)(long)1)
+
+#define JOB_STATUS_FORMAT    "[%u] %-22s %.40s\n"
+
+#define _SPECIAL_VARS_STR     "_*@$!?#-"
+#define SPECIAL_VARS_STR     ("_*@$!?#-" + 1)
+#define NUMERIC_SPECVARS_STR ("_*@$!?#-" + 3)
+#if BASH_PATTERN_SUBST
+/* Support / and // replace ops */
+/* Note that // is stored as \ in "encoded" string representation */
+# define VAR_ENCODED_SUBST_OPS      "\\/%#:-=+?"
+# define VAR_SUBST_OPS             ("\\/%#:-=+?" + 1)
+# define MINUS_PLUS_EQUAL_QUESTION ("\\/%#:-=+?" + 5)
+#else
+# define VAR_ENCODED_SUBST_OPS      "%#:-=+?"
+# define VAR_SUBST_OPS              "%#:-=+?"
+# define MINUS_PLUS_EQUAL_QUESTION ("%#:-=+?" + 3)
+#endif
+
+#define SPECIAL_VAR_SYMBOL_STR "\3"
+#define SPECIAL_VAR_SYMBOL       3
+/* The "variable" with name "\1" emits string "\3". Testcase: "echo ^C" */
+#define SPECIAL_VAR_QUOTED_SVS   1
+
+struct variable;
+
+static const char hush_version_str[] ALIGN1 = "HUSH_VERSION="BB_VER;
+
+/* This supports saving pointers malloced in vfork child,
+ * to be freed in the parent.
+ */
+#if !BB_MMU
+typedef struct nommu_save_t {
+	struct variable *old_vars;
+	char **argv;
+	char **argv_from_re_execing;
+} nommu_save_t;
+#endif
+
+enum {
+	RES_NONE  = 0,
+#if ENABLE_HUSH_IF
+	RES_IF    ,
+	RES_THEN  ,
+	RES_ELIF  ,
+	RES_ELSE  ,
+	RES_FI    ,
+#endif
+#if ENABLE_HUSH_LOOPS
+	RES_FOR   ,
+	RES_WHILE ,
+	RES_UNTIL ,
+	RES_DO    ,
+	RES_DONE  ,
+#endif
+#if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
+	RES_IN    ,
+#endif
+#if ENABLE_HUSH_CASE
+	RES_CASE  ,
+	/* three pseudo-keywords support contrived "case" syntax: */
+	RES_CASE_IN,   /* "case ... IN", turns into RES_MATCH when IN is observed */
+	RES_MATCH ,    /* "word)" */
+	RES_CASE_BODY, /* "this command is inside CASE" */
+	RES_ESAC  ,
+#endif
+	RES_XXXX  ,
+	RES_SNTX
+};
+
+typedef struct o_string {
+	char *data;
+	int length; /* position where data is appended */
+	int maxlen;
+	int o_expflags;
+	/* At least some part of the string was inside '' or "",
+	 * possibly empty one: word"", wo''rd etc. */
+	smallint has_quoted_part;
+	smallint has_empty_slot;
+	smallint ended_in_ifs;
+} o_string;
+enum {
+	EXP_FLAG_SINGLEWORD     = 0x80, /* must be 0x80 */
+	EXP_FLAG_GLOB           = 0x2,
+	/* Protect newly added chars against globbing
+	 * by prepending \ to *, ?, [, \ */
+	EXP_FLAG_ESC_GLOB_CHARS = 0x1,
+};
+/* Used for initialization: o_string foo = NULL_O_STRING; */
+#define NULL_O_STRING { NULL }
+
+#ifndef debug_printf_parse
+static const char *const assignment_flag[] = {
+	"MAYBE_ASSIGNMENT",
+	"DEFINITELY_ASSIGNMENT",
+	"NOT_ASSIGNMENT",
+	"WORD_IS_KEYWORD",
+};
+#endif
+
+/* We almost can use standard FILE api, but we need an ability to move
+ * its fd when redirects coincide with it. No api exists for that
+ * (RFE for it at https://sourceware.org/bugzilla/show_bug.cgi?id=21902).
+ * HFILE is our internal alternative. Only supports reading.
+ * Since we now can, we incorporate linked list of all opened HFILEs
+ * into the struct (used to be a separate mini-list).
+ */
+typedef struct HFILE {
+	char *cur;
+	char *end;
+	struct HFILE *next_hfile;
+	int fd;
+	char buf[1024];
+} HFILE;
+
+typedef struct in_str {
+	const char *p;
+	int peek_buf[2];
+	int last_char;
+	HFILE *file;
+} in_str;
+
+/* The descrip member of this structure is only used to make
+ * debugging output pretty */
+static const struct {
+	int32_t mode;
+	signed char default_fd;
+	char descrip[3];
+} redir_table[] ALIGN4 = {
+	{ O_RDONLY,                  0, "<"  },
+	{ O_CREAT|O_TRUNC|O_WRONLY,  1, ">"  },
+	{ O_CREAT|O_APPEND|O_WRONLY, 1, ">>" },
+	{ O_CREAT|O_RDWR,            1, "<>" },
+	{ O_RDONLY,                  0, "<<" },
+/* Should not be needed. Bogus default_fd helps in debugging */
+/*	{ O_RDONLY,                 77, "<<" }, */
+};
+
+struct redir_struct {
+	struct redir_struct *next;
+	char *rd_filename;          /* filename */
+	int rd_fd;                  /* fd to redirect */
+	/* fd to redirect to, or -3 if rd_fd is to be closed (n>&-) */
+	int rd_dup;
+	smallint rd_type;           /* (enum redir_type) */
+	/* note: for heredocs, rd_filename contains heredoc delimiter,
+	 * and subsequently heredoc itself; and rd_dup is a bitmask:
+	 * bit 0: do we need to trim leading tabs?
+	 * bit 1: is heredoc quoted (<<'delim' syntax) ?
+	 */
+};
+typedef enum redir_type {
+	REDIRECT_INPUT     = 0,
+	REDIRECT_OVERWRITE = 1,
+	REDIRECT_APPEND    = 2,
+	REDIRECT_IO        = 3,
+	REDIRECT_HEREDOC   = 4,
+	REDIRECT_HEREDOC2  = 5, /* REDIRECT_HEREDOC after heredoc is loaded */
+
+	REDIRFD_CLOSE      = -3,
+	REDIRFD_SYNTAX_ERR = -2,
+	REDIRFD_TO_FILE    = -1,
+	/* otherwise, rd_fd is redirected to rd_dup */
+
+	HEREDOC_SKIPTABS = 1,
+	HEREDOC_QUOTED   = 2,
+} redir_type;
+
+
+struct command {
+	pid_t pid;                  /* 0 if exited */
+	unsigned assignment_cnt;    /* how many argv[i] are assignments? */
+#if ENABLE_HUSH_LINENO_VAR
+	unsigned lineno;
+#endif
+	smallint cmd_type;          /* CMD_xxx */
+#define CMD_NORMAL   0
+#define CMD_SUBSHELL 1
+#if BASH_TEST2
+/* used for "[[ EXPR ]]" */
+# define CMD_TEST2_SINGLEWORD_NOGLOB 2
+#endif
+#if BASH_TEST2 || ENABLE_HUSH_LOCAL || ENABLE_HUSH_EXPORT || ENABLE_HUSH_READONLY
+/* used to prevent word splitting and globbing in "export v=t*" */
+# define CMD_SINGLEWORD_NOGLOB 3
+#endif
+#if ENABLE_HUSH_FUNCTIONS
+# define CMD_FUNCDEF 4
+#endif
+
+	smalluint cmd_exitcode;
+	/* if non-NULL, this "command" is { list }, ( list ), or a compound statement */
+	struct pipe *group;
+#if !BB_MMU
+	char *group_as_string;
+#endif
+#if ENABLE_HUSH_FUNCTIONS
+	struct function *child_func;
+/* This field is used to prevent a bug here:
+ * while...do f1() {a;}; f1; f1() {b;}; f1; done
+ * When we execute "f1() {a;}" cmd, we create new function and clear
+ * cmd->group, cmd->group_as_string, cmd->argv[0].
+ * When we execute "f1() {b;}", we notice that f1 exists,
+ * and that its "parent cmd" struct is still "alive",
+ * we put those fields back into cmd->xxx
+ * (struct function has ->parent_cmd ptr to facilitate that).
+ * When we loop back, we can execute "f1() {a;}" again and set f1 correctly.
+ * Without this trick, loop would execute a;b;b;b;...
+ * instead of correct sequence a;b;a;b;...
+ * When command is freed, it severs the link
+ * (sets ->child_func->parent_cmd to NULL).
+ */
+#endif
+	char **argv;                /* command name and arguments */
+/* argv vector may contain variable references (^Cvar^C, ^C0^C etc)
+ * and on execution these are substituted with their values.
+ * Substitution can make _several_ words out of one argv[n]!
+ * Example: argv[0]=='.^C*^C.' here: echo .$*.
+ * References of the form ^C`cmd arg^C are `cmd arg` substitutions.
+ */
+	struct redir_struct *redirects; /* I/O redirections */
+};
+/* Is there anything in this command at all? */
+#define IS_NULL_CMD(cmd) \
+	(!(cmd)->group && !(cmd)->argv && !(cmd)->redirects)
+
+struct pipe {
+	struct pipe *next;
+	int num_cmds;               /* total number of commands in pipe */
+	int alive_cmds;             /* number of commands running (not exited) */
+	int stopped_cmds;           /* number of commands alive, but stopped */
+#if ENABLE_HUSH_JOB
+	unsigned jobid;             /* job number */
+	pid_t pgrp;                 /* process group ID for the job */
+	char *cmdtext;              /* name of job */
+#endif
+	struct command *cmds;       /* array of commands in pipe */
+	smallint followup;          /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
+	IF_HAS_KEYWORDS(smallint pi_inverted;) /* "! cmd | cmd" */
+	IF_HAS_KEYWORDS(smallint res_word;) /* needed for if, for, while, until... */
+};
+typedef enum pipe_style {
+	PIPE_SEQ = 0,
+	PIPE_AND = 1,
+	PIPE_OR  = 2,
+	PIPE_BG  = 3,
+} pipe_style;
+/* Is there anything in this pipe at all? */
+#define IS_NULL_PIPE(pi) \
+	((pi)->num_cmds == 0 IF_HAS_KEYWORDS( && (pi)->res_word == RES_NONE))
+
+/* This holds pointers to the various results of parsing */
+struct parse_context {
+	/* linked list of pipes */
+	struct pipe *list_head;
+	/* last pipe (being constructed right now) */
+	struct pipe *pipe;
+	/* last command in pipe (being constructed right now) */
+	struct command *command;
+	/* last redirect in command->redirects list */
+	struct redir_struct *pending_redirect;
+	o_string word;
+#if !BB_MMU
+	o_string as_string;
+#endif
+	smallint is_assignment; /* 0:maybe, 1:yes, 2:no, 3:keyword */
+#if HAS_KEYWORDS
+	smallint ctx_res_w;
+	smallint ctx_inverted; /* "! cmd | cmd" */
+#if ENABLE_HUSH_CASE
+	smallint ctx_dsemicolon; /* ";;" seen */
+#endif
+	/* bitmask of FLAG_xxx, for figuring out valid reserved words */
+	int old_flag;
+	/* group we are enclosed in:
+	 * example: "if pipe1; pipe2; then pipe3; fi"
+	 * when we see "if" or "then", we malloc and copy current context,
+	 * and make ->stack point to it. then we parse pipeN.
+	 * when closing "then" / fi" / whatever is found,
+	 * we move list_head into ->stack->command->group,
+	 * copy ->stack into current context, and delete ->stack.
+	 * (parsing of { list } and ( list ) doesn't use this method)
+	 */
+	struct parse_context *stack;
+#endif
+};
+enum {
+	MAYBE_ASSIGNMENT      = 0,
+	DEFINITELY_ASSIGNMENT = 1,
+	NOT_ASSIGNMENT        = 2,
+	/* Not an assignment, but next word may be: "if v=xyz cmd;" */
+	WORD_IS_KEYWORD       = 3,
+};
+
+/* On program start, environ points to initial environment.
+ * putenv adds new pointers into it, unsetenv removes them.
+ * Neither of these (de)allocates the strings.
+ * setenv allocates new strings in malloc space and does putenv,
+ * and thus setenv is unusable (leaky) for shell's purposes */
+#define setenv(...) setenv_is_leaky_dont_use()
+struct variable {
+	struct variable *next;
+	char *varstr;        /* points to "name=" portion */
+	int max_len;         /* if > 0, name is part of initial env; else name is malloced */
+	uint16_t var_nest_level;
+	smallint flg_export; /* putenv should be done on this var */
+	smallint flg_read_only;
+};
+
+enum {
+	BC_BREAK = 1,
+	BC_CONTINUE = 2,
+};
+
+#if ENABLE_HUSH_FUNCTIONS
+struct function {
+	struct function *next;
+	char *name;
+	struct command *parent_cmd;
+	struct pipe *body;
+# if !BB_MMU
+	char *body_as_string;
+# endif
+};
+#endif
+
+
+/* set -/+o OPT support. (TODO: make it optional)
+ * bash supports the following opts:
+ * allexport       off
+ * braceexpand     on
+ * emacs           on
+ * errexit         off
+ * errtrace        off
+ * functrace       off
+ * hashall         on
+ * histexpand      off
+ * history         on
+ * ignoreeof       off
+ * interactive-comments    on
+ * keyword         off
+ * monitor         on
+ * noclobber       off
+ * noexec          off
+ * noglob          off
+ * nolog           off
+ * notify          off
+ * nounset         off
+ * onecmd          off
+ * physical        off
+ * pipefail        off
+ * posix           off
+ * privileged      off
+ * verbose         off
+ * vi              off
+ * xtrace          off
+ */
+static const char o_opt_strings[] ALIGN1 =
+	"pipefail\0"
+	"noexec\0"
+	"errexit\0"
+#if ENABLE_HUSH_MODE_X
+	"xtrace\0"
+#endif
+	;
+enum {
+	OPT_O_PIPEFAIL,
+	OPT_O_NOEXEC,
+	OPT_O_ERREXIT,
+#if ENABLE_HUSH_MODE_X
+	OPT_O_XTRACE,
+#endif
+	NUM_OPT_O
+};
+
+/* "Globals" within this file */
+/* Sorted roughly by size (smaller offsets == smaller code) */
+struct globals {
+	/* interactive_fd != 0 means we are an interactive shell.
+	 * If we are, then saved_tty_pgrp can also be != 0, meaning
+	 * that controlling tty is available. With saved_tty_pgrp == 0,
+	 * job control still works, but terminal signals
+	 * (^C, ^Z, ^Y, ^\) won't work at all, and background
+	 * process groups can only be created with "cmd &".
+	 * With saved_tty_pgrp != 0, hush will use tcsetpgrp()
+	 * to give tty to the foreground process group,
+	 * and will take it back when the group is stopped (^Z)
+	 * or killed (^C).
+	 */
+#if ENABLE_HUSH_INTERACTIVE
+	/* 'interactive_fd' is a fd# open to ctty, if we have one
+	 * _AND_ if we decided to act interactively */
+	int interactive_fd;
+	IF_NOT_FEATURE_EDITING_FANCY_PROMPT(char *PS1;)
+# define G_interactive_fd (G.interactive_fd)
+#else
+# define G_interactive_fd 0
+#endif
+#if ENABLE_FEATURE_EDITING
+	line_input_t *line_input_state;
+#endif
+	pid_t root_pid;
+	pid_t root_ppid;
+	pid_t last_bg_pid;
+#if ENABLE_HUSH_RANDOM_SUPPORT
+	random_t random_gen;
+#endif
+#if ENABLE_HUSH_JOB
+	int run_list_level;
+	unsigned last_jobid;
+	pid_t saved_tty_pgrp;
+	struct pipe *job_list;
+# define G_saved_tty_pgrp (G.saved_tty_pgrp)
+#else
+# define G_saved_tty_pgrp 0
+#endif
+	/* How deeply are we in context where "set -e" is ignored */
+	int errexit_depth;
+	/* "set -e" rules (do we follow them correctly?):
+	 * Exit if pipe, list, or compound command exits with a non-zero status.
+	 * Shell does not exit if failed command is part of condition in
+	 * if/while, part of && or || list except the last command, any command
+	 * in a pipe but the last, or if the command's return value is being
+	 * inverted with !. If a compound command other than a subshell returns a
+	 * non-zero status because a command failed while -e was being ignored, the
+	 * shell does not exit. A trap on ERR, if set, is executed before the shell
+	 * exits [ERR is a bashism].
+	 *
+	 * If a compound command or function executes in a context where -e is
+	 * ignored, none of the commands executed within are affected by the -e
+	 * setting. If a compound command or function sets -e while executing in a
+	 * context where -e is ignored, that setting does not have any effect until
+	 * the compound command or the command containing the function call completes.
+	 */
+
+	char o_opt[NUM_OPT_O];
+#if ENABLE_HUSH_MODE_X
+# define G_x_mode (G.o_opt[OPT_O_XTRACE])
+#else
+# define G_x_mode 0
+#endif
+	char opt_s;
+	char opt_c;
+#if ENABLE_HUSH_INTERACTIVE
+	smallint promptmode; /* 0: PS1, 1: PS2 */
+#endif
+	smallint flag_SIGINT;
+#if ENABLE_HUSH_LOOPS
+	smallint flag_break_continue;
+#endif
+#if ENABLE_HUSH_FUNCTIONS
+	/* 0: outside of a function (or sourced file)
+	 * -1: inside of a function, ok to use return builtin
+	 * 1: return is invoked, skip all till end of func
+	 */
+	smallint flag_return_in_progress;
+# define G_flag_return_in_progress (G.flag_return_in_progress)
+#else
+# define G_flag_return_in_progress 0
+#endif
+	smallint exiting; /* used to prevent EXIT trap recursion */
+	/* These support $? */
+	smalluint last_exitcode;
+	smalluint expand_exitcode;
+	smalluint last_bg_pid_exitcode;
+#if ENABLE_HUSH_SET
+	/* are global_argv and global_argv[1..n] malloced? (note: not [0]) */
+	smalluint global_args_malloced;
+# define G_global_args_malloced (G.global_args_malloced)
+#else
+# define G_global_args_malloced 0
+#endif
+#if ENABLE_HUSH_BASH_COMPAT
+	int dead_job_exitcode; /* for "wait -n" */
+#endif
+	/* how many non-NULL argv's we have. NB: $# + 1 */
+	int global_argc;
+	char **global_argv;
+#if !BB_MMU
+	char *argv0_for_re_execing;
+#endif
+#if ENABLE_HUSH_LOOPS
+	unsigned depth_break_continue;
+	unsigned depth_of_loop;
+#endif
+#if ENABLE_HUSH_GETOPTS
+	unsigned getopt_count;
+#endif
+	const char *ifs;
+	char *ifs_whitespace; /* = G.ifs or malloced */
+	const char *cwd;
+	struct variable *top_var;
+	char **expanded_assignments;
+	struct variable **shadowed_vars_pp;
+	unsigned var_nest_level;
+#if ENABLE_HUSH_FUNCTIONS
+# if ENABLE_HUSH_LOCAL
+	unsigned func_nest_level; /* solely to prevent "local v" in non-functions */
+# endif
+	struct function *top_func;
+#endif
+	/* Signal and trap handling */
+#if ENABLE_HUSH_FAST
+	unsigned count_SIGCHLD;
+	unsigned handled_SIGCHLD;
+	smallint we_have_children;
+#endif
+#if ENABLE_HUSH_LINENO_VAR
+	unsigned parse_lineno;
+	unsigned execute_lineno;
+#endif
+	HFILE *HFILE_list;
+	HFILE *HFILE_stdin;
+	/* Which signals have non-DFL handler (even with no traps set)?
+	 * Set at the start to:
+	 * (SIGQUIT + maybe SPECIAL_INTERACTIVE_SIGS + maybe SPECIAL_JOBSTOP_SIGS)
+	 * SPECIAL_INTERACTIVE_SIGS are cleared after fork.
+	 * The rest is cleared right before execv syscalls.
+	 * Other than these two times, never modified.
+	 */
+	unsigned special_sig_mask;
+#if ENABLE_HUSH_JOB
+	unsigned fatal_sig_mask;
+# define G_fatal_sig_mask (G.fatal_sig_mask)
+#else
+# define G_fatal_sig_mask 0
+#endif
+#if ENABLE_HUSH_TRAP
+	int pre_trap_exitcode;
+# if ENABLE_HUSH_FUNCTIONS
+	int return_exitcode;
+# endif
+	char **traps; /* char *traps[NSIG] */
+# define G_traps G.traps
+#else
+# define G_traps ((char**)NULL)
+#endif
+	sigset_t pending_set;
+#if ENABLE_HUSH_MEMLEAK
+	unsigned long memleak_value;
+#endif
+#if ENABLE_HUSH_MODE_X
+	unsigned x_mode_depth;
+	/* "set -x" output should not be redirectable with subsequent 2>FILE.
+	 * We dup fd#2 to x_mode_fd when "set -x" is executed, and use it
+	 * for all subsequent output.
+	 */
+	int x_mode_fd;
+	o_string x_mode_buf;
+#endif
+#if HUSH_DEBUG >= 2
+	int debug_indent;
+#endif
+	struct sigaction sa;
+	char optstring_buf[sizeof("eixcs")];
+#if BASH_EPOCH_VARS
+	char epoch_buf[sizeof("%llu.nnnnnn") + sizeof(long long)*3];
+#endif
+#if ENABLE_FEATURE_EDITING
+	char user_input_buf[CONFIG_FEATURE_EDITING_MAX_LEN];
+#endif
+};
+#define G (*ptr_to_globals)
+/* Not #defining name to G.name - this quickly gets unwieldy
+ * (too many defines). Also, I actually prefer to see when a variable
+ * is global, thus "G." prefix is a useful hint */
+#define INIT_G() do { \
+	SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
+	/* memset(&G.sa, 0, sizeof(G.sa)); */  \
+	sigfillset(&G.sa.sa_mask); \
+	G.sa.sa_flags = SA_RESTART; \
+} while (0)
+
+
+/* Function prototypes for builtins */
+static int builtin_cd(char **argv) FAST_FUNC;
+#if ENABLE_HUSH_ECHO
+static int builtin_echo(char **argv) FAST_FUNC;
+#endif
+static int builtin_eval(char **argv) FAST_FUNC;
+static int builtin_exec(char **argv) FAST_FUNC;
+static int builtin_exit(char **argv) FAST_FUNC;
+#if ENABLE_HUSH_EXPORT
+static int builtin_export(char **argv) FAST_FUNC;
+#endif
+#if ENABLE_HUSH_READONLY
+static int builtin_readonly(char **argv) FAST_FUNC;
+#endif
+#if ENABLE_HUSH_JOB
+static int builtin_fg_bg(char **argv) FAST_FUNC;
+static int builtin_jobs(char **argv) FAST_FUNC;
+#endif
+#if ENABLE_HUSH_GETOPTS
+static int builtin_getopts(char **argv) FAST_FUNC;
+#endif
+#if ENABLE_HUSH_HELP
+static int builtin_help(char **argv) FAST_FUNC;
+#endif
+#if MAX_HISTORY && ENABLE_FEATURE_EDITING
+static int builtin_history(char **argv) FAST_FUNC;
+#endif
+#if ENABLE_HUSH_LOCAL
+static int builtin_local(char **argv) FAST_FUNC;
+#endif
+#if ENABLE_HUSH_MEMLEAK
+static int builtin_memleak(char **argv) FAST_FUNC;
+#endif
+#if ENABLE_HUSH_PRINTF
+static int builtin_printf(char **argv) FAST_FUNC;
+#endif
+static int builtin_pwd(char **argv) FAST_FUNC;
+#if ENABLE_HUSH_READ
+static int builtin_read(char **argv) FAST_FUNC;
+#endif
+#if ENABLE_HUSH_SET
+static int builtin_set(char **argv) FAST_FUNC;
+#endif
+static int builtin_shift(char **argv) FAST_FUNC;
+static int builtin_source(char **argv) FAST_FUNC;
+#if ENABLE_HUSH_TEST || BASH_TEST2
+static int builtin_test(char **argv) FAST_FUNC;
+#endif
+#if ENABLE_HUSH_TRAP
+static int builtin_trap(char **argv) FAST_FUNC;
+#endif
+#if ENABLE_HUSH_TYPE
+static int builtin_type(char **argv) FAST_FUNC;
+#endif
+#if ENABLE_HUSH_TIMES
+static int builtin_times(char **argv) FAST_FUNC;
+#endif
+static int builtin_true(char **argv) FAST_FUNC;
+#if ENABLE_HUSH_UMASK
+static int builtin_umask(char **argv) FAST_FUNC;
+#endif
+#if ENABLE_HUSH_UNSET
+static int builtin_unset(char **argv) FAST_FUNC;
+#endif
+#if ENABLE_HUSH_KILL
+static int builtin_kill(char **argv) FAST_FUNC;
+#endif
+#if ENABLE_HUSH_WAIT
+static int builtin_wait(char **argv) FAST_FUNC;
+#endif
+#if ENABLE_HUSH_LOOPS
+static int builtin_break(char **argv) FAST_FUNC;
+static int builtin_continue(char **argv) FAST_FUNC;
+#endif
+#if ENABLE_HUSH_FUNCTIONS
+static int builtin_return(char **argv) FAST_FUNC;
+#endif
+
+/* Table of built-in functions.  They can be forked or not, depending on
+ * context: within pipes, they fork.  As simple commands, they do not.
+ * When used in non-forking context, they can change global variables
+ * in the parent shell process.  If forked, of course they cannot.
+ * For example, 'unset foo | whatever' will parse and run, but foo will
+ * still be set at the end. */
+struct built_in_command {
+	const char *b_cmd;
+	int (*b_function)(char **argv) FAST_FUNC;
+#if ENABLE_HUSH_HELP
+	const char *b_descr;
+# define BLTIN(cmd, func, help) { cmd, func, help }
+#else
+# define BLTIN(cmd, func, help) { cmd, func }
+#endif
+};
+
+static const struct built_in_command bltins1[] ALIGN_PTR = {
+	BLTIN("."        , builtin_source  , "Run commands in file"),
+	BLTIN(":"        , builtin_true    , NULL),
+#if ENABLE_HUSH_JOB
+	BLTIN("bg"       , builtin_fg_bg   , "Resume job in background"),
+#endif
+#if ENABLE_HUSH_LOOPS
+	BLTIN("break"    , builtin_break   , "Exit loop"),
+#endif
+	BLTIN("cd"       , builtin_cd      , "Change directory"),
+#if ENABLE_HUSH_LOOPS
+	BLTIN("continue" , builtin_continue, "Start new loop iteration"),
+#endif
+	BLTIN("eval"     , builtin_eval    , "Construct and run shell command"),
+	BLTIN("exec"     , builtin_exec    , "Execute command, don't return to shell"),
+	BLTIN("exit"     , builtin_exit    , NULL),
+#if ENABLE_HUSH_EXPORT
+	BLTIN("export"   , builtin_export  , "Set environment variables"),
+#endif
+#if ENABLE_HUSH_JOB
+	BLTIN("fg"       , builtin_fg_bg   , "Bring job to foreground"),
+#endif
+#if ENABLE_HUSH_GETOPTS
+	BLTIN("getopts"  , builtin_getopts , NULL),
+#endif
+#if ENABLE_HUSH_HELP
+	BLTIN("help"     , builtin_help    , NULL),
+#endif
+#if MAX_HISTORY && ENABLE_FEATURE_EDITING
+	BLTIN("history"  , builtin_history , "Show history"),
+#endif
+#if ENABLE_HUSH_JOB
+	BLTIN("jobs"     , builtin_jobs    , "List jobs"),
+#endif
+#if ENABLE_HUSH_KILL
+	BLTIN("kill"     , builtin_kill    , "Send signals to processes"),
+#endif
+#if ENABLE_HUSH_LOCAL
+	BLTIN("local"    , builtin_local   , "Set local variables"),
+#endif
+#if ENABLE_HUSH_MEMLEAK
+	BLTIN("memleak"  , builtin_memleak , NULL),
+#endif
+#if ENABLE_HUSH_READ
+	BLTIN("read"     , builtin_read    , "Input into variable"),
+#endif
+#if ENABLE_HUSH_READONLY
+	BLTIN("readonly" , builtin_readonly, "Make variables read-only"),
+#endif
+#if ENABLE_HUSH_FUNCTIONS
+	BLTIN("return"   , builtin_return  , "Return from function"),
+#endif
+#if ENABLE_HUSH_SET
+	BLTIN("set"      , builtin_set     , "Set positional parameters"),
+#endif
+	BLTIN("shift"    , builtin_shift   , "Shift positional parameters"),
+#if BASH_SOURCE
+	BLTIN("source"   , builtin_source  , NULL),
+#endif
+#if ENABLE_HUSH_TIMES
+	BLTIN("times"    , builtin_times   , NULL),
+#endif
+#if ENABLE_HUSH_TRAP
+	BLTIN("trap"     , builtin_trap    , "Trap signals"),
+#endif
+	BLTIN("true"     , builtin_true    , NULL),
+#if ENABLE_HUSH_TYPE
+	BLTIN("type"     , builtin_type    , "Show command type"),
+#endif
+#if ENABLE_HUSH_ULIMIT
+	BLTIN("ulimit"   , shell_builtin_ulimit, "Control resource limits"),
+#endif
+#if ENABLE_HUSH_UMASK
+	BLTIN("umask"    , builtin_umask   , "Set file creation mask"),
+#endif
+#if ENABLE_HUSH_UNSET
+	BLTIN("unset"    , builtin_unset   , "Unset variables"),
+#endif
+#if ENABLE_HUSH_WAIT
+	BLTIN("wait"     , builtin_wait    , "Wait for process to finish"),
+#endif
+};
+/* These builtins won't be used if we are on NOMMU and need to re-exec
+ * (it's cheaper to run an external program in this case):
+ */
+static const struct built_in_command bltins2[] ALIGN_PTR = {
+#if ENABLE_HUSH_TEST
+	BLTIN("["        , builtin_test    , NULL),
+#endif
+#if BASH_TEST2
+	BLTIN("[["       , builtin_test    , NULL),
+#endif
+#if ENABLE_HUSH_ECHO
+	BLTIN("echo"     , builtin_echo    , NULL),
+#endif
+#if ENABLE_HUSH_PRINTF
+	BLTIN("printf"   , builtin_printf  , NULL),
+#endif
+	BLTIN("pwd"      , builtin_pwd     , NULL),
+#if ENABLE_HUSH_TEST
+	BLTIN("test"     , builtin_test    , NULL),
+#endif
+};
+
+
+/* Debug printouts.
+ */
+#if HUSH_DEBUG >= 2
+/* prevent disasters with G.debug_indent < 0 */
+# define indent() fdprintf(2, "%*s", (G.debug_indent * 2) & 0xff, "")
+# define debug_enter() (G.debug_indent++)
+# define debug_leave() (G.debug_indent--)
+#else
+# define indent()      ((void)0)
+# define debug_enter() ((void)0)
+# define debug_leave() ((void)0)
+#endif
+
+#ifndef debug_printf
+# define debug_printf(...) (indent(), fdprintf(2, __VA_ARGS__))
+#endif
+
+#ifndef debug_printf_parse
+# define debug_printf_parse(...) (indent(), fdprintf(2, __VA_ARGS__))
+#endif
+
+#ifndef debug_printf_heredoc
+# define debug_printf_heredoc(...) (indent(), fdprintf(2, __VA_ARGS__))
+#endif
+
+#ifndef debug_printf_exec
+#define debug_printf_exec(...) (indent(), fdprintf(2, __VA_ARGS__))
+#endif
+
+#ifndef debug_printf_env
+# define debug_printf_env(...) (indent(), fdprintf(2, __VA_ARGS__))
+#endif
+
+#ifndef debug_printf_jobs
+# define debug_printf_jobs(...) (indent(), fdprintf(2, __VA_ARGS__))
+# define DEBUG_JOBS 1
+#else
+# define DEBUG_JOBS 0
+#endif
+
+#ifndef debug_printf_expand
+# define debug_printf_expand(...) (indent(), fdprintf(2, __VA_ARGS__))
+# define DEBUG_EXPAND 1
+#else
+# define DEBUG_EXPAND 0
+#endif
+
+#ifndef debug_printf_varexp
+# define debug_printf_varexp(...) (indent(), fdprintf(2, __VA_ARGS__))
+#endif
+
+#ifndef debug_printf_glob
+# define debug_printf_glob(...) (indent(), fdprintf(2, __VA_ARGS__))
+# define DEBUG_GLOB 1
+#else
+# define DEBUG_GLOB 0
+#endif
+
+#ifndef debug_printf_redir
+# define debug_printf_redir(...) (indent(), fdprintf(2, __VA_ARGS__))
+#endif
+
+#ifndef debug_printf_list
+# define debug_printf_list(...) (indent(), fdprintf(2, __VA_ARGS__))
+#endif
+
+#ifndef debug_printf_subst
+# define debug_printf_subst(...) (indent(), fdprintf(2, __VA_ARGS__))
+#endif
+
+#ifndef debug_printf_prompt
+# define debug_printf_prompt(...) (indent(), fdprintf(2, __VA_ARGS__))
+#endif
+
+#ifndef debug_printf_clean
+# define debug_printf_clean(...) (indent(), fdprintf(2, __VA_ARGS__))
+# define DEBUG_CLEAN 1
+#else
+# define DEBUG_CLEAN 0
+#endif
+
+#if DEBUG_EXPAND
+static void debug_print_strings(const char *prefix, char **vv)
+{
+	indent();
+	fdprintf(2, "%s:\n", prefix);
+	while (*vv)
+		fdprintf(2, " '%s'\n", *vv++);
+}
+#else
+# define debug_print_strings(prefix, vv) ((void)0)
+#endif
+
+
+/* Leak hunting. Use hush_leaktool.sh for post-processing.
+ */
+#if LEAK_HUNTING
+static void *xxmalloc(int lineno, size_t size)
+{
+	void *ptr = xmalloc((size + 0xff) & ~0xff);
+	fdprintf(2, "line %d: malloc %p\n", lineno, ptr);
+	return ptr;
+}
+static void *xxrealloc(int lineno, void *ptr, size_t size)
+{
+	ptr = xrealloc(ptr, (size + 0xff) & ~0xff);
+	fdprintf(2, "line %d: realloc %p\n", lineno, ptr);
+	return ptr;
+}
+static char *xxstrdup(int lineno, const char *str)
+{
+	char *ptr = xstrdup(str);
+	fdprintf(2, "line %d: strdup %p\n", lineno, ptr);
+	return ptr;
+}
+static void xxfree(void *ptr)
+{
+	fdprintf(2, "free %p\n", ptr);
+	free(ptr);
+}
+# define xmalloc(s)     xxmalloc(__LINE__, s)
+# define xrealloc(p, s) xxrealloc(__LINE__, p, s)
+# define xstrdup(s)     xxstrdup(__LINE__, s)
+# define free(p)        xxfree(p)
+#endif
+
+
+/* Syntax and runtime errors. They always abort scripts.
+ * In interactive use they usually discard unparsed and/or unexecuted commands
+ * and return to the prompt.
+ * HUSH_DEBUG >= 2 prints line number in this file where it was detected.
+ */
+#if HUSH_DEBUG < 2
+# define msg_and_die_if_script(lineno, ...)     msg_and_die_if_script(__VA_ARGS__)
+# define syntax_error(lineno, msg)              syntax_error(msg)
+# define syntax_error_at(lineno, msg)           syntax_error_at(msg)
+# define syntax_error_unterm_ch(lineno, ch)     syntax_error_unterm_ch(ch)
+# define syntax_error_unterm_str(lineno, s)     syntax_error_unterm_str(s)
+# define syntax_error_unexpected_ch(lineno, ch) syntax_error_unexpected_ch(ch)
+#endif
+
+static void die_if_script(void)
+{
+	if (!G_interactive_fd) {
+		if (G.last_exitcode) /* sometines it's 2, not 1 (bash compat) */
+			xfunc_error_retval = G.last_exitcode;
+		xfunc_die();
+	}
+}
+
+static void msg_and_die_if_script(unsigned lineno, const char *fmt, ...)
+{
+	va_list p;
+
+#if HUSH_DEBUG >= 2
+	bb_error_msg("hush.c:%u", lineno);
+#endif
+	va_start(p, fmt);
+	bb_verror_msg(fmt, p, NULL);
+	va_end(p);
+	die_if_script();
+}
+
+static void syntax_error(unsigned lineno UNUSED_PARAM, const char *msg)
+{
+	if (msg)
+		bb_error_msg("syntax error: %s", msg);
+	else
+		bb_simple_error_msg("syntax error");
+	die_if_script();
+}
+
+static void syntax_error_at(unsigned lineno UNUSED_PARAM, const char *msg)
+{
+	bb_error_msg("syntax error at '%s'", msg);
+	die_if_script();
+}
+
+static void syntax_error_unterm_str(unsigned lineno UNUSED_PARAM, const char *s)
+{
+	bb_error_msg("syntax error: unterminated %s", s);
+//? source4.tests fails: in bash, echo ${^} in script does not terminate the script
+//	die_if_script();
+}
+
+static void syntax_error_unterm_ch(unsigned lineno, char ch)
+{
+	char msg[2] = { ch, '\0' };
+	syntax_error_unterm_str(lineno, msg);
+}
+
+static void syntax_error_unexpected_ch(unsigned lineno UNUSED_PARAM, int ch)
+{
+	char msg[2];
+	msg[0] = ch;
+	msg[1] = '\0';
+#if HUSH_DEBUG >= 2
+	bb_error_msg("hush.c:%u", lineno);
+#endif
+	bb_error_msg("syntax error: unexpected %s", ch == EOF ? "EOF" : msg);
+	die_if_script();
+}
+
+#if HUSH_DEBUG < 2
+# undef msg_and_die_if_script
+# undef syntax_error
+# undef syntax_error_at
+# undef syntax_error_unterm_ch
+# undef syntax_error_unterm_str
+# undef syntax_error_unexpected_ch
+#else
+# define msg_and_die_if_script(...)     msg_and_die_if_script(__LINE__, __VA_ARGS__)
+# define syntax_error(msg)              syntax_error(__LINE__, msg)
+# define syntax_error_at(msg)           syntax_error_at(__LINE__, msg)
+# define syntax_error_unterm_ch(ch)     syntax_error_unterm_ch(__LINE__, ch)
+# define syntax_error_unterm_str(s)     syntax_error_unterm_str(__LINE__, s)
+# define syntax_error_unexpected_ch(ch) syntax_error_unexpected_ch(__LINE__, ch)
+#endif
+
+
+/* Utility functions
+ */
+/* Replace each \x with x in place, return ptr past NUL. */
+static char *unbackslash(char *src)
+{
+	char *dst = src = strchrnul(src, '\\');
+	while (1) {
+		if (*src == '\\') {
+			src++;
+			if (*src != '\0') {
+				/* \x -> x */
+				*dst++ = *src++;
+				continue;
+			}
+			/* else: "\<nul>". Do not delete this backslash.
+			 * Testcase: eval 'echo ok\'
+			 */
+			*dst++ = '\\';
+			/* fallthrough */
+		}
+		if ((*dst++ = *src++) == '\0')
+			break;
+	}
+	return dst;
+}
+
+static char **add_strings_to_strings(char **strings, char **add, int need_to_dup)
+{
+	int i;
+	unsigned count1;
+	unsigned count2;
+	char **v;
+
+	v = strings;
+	count1 = 0;
+	if (v) {
+		while (*v) {
+			count1++;
+			v++;
+		}
+	}
+	count2 = 0;
+	v = add;
+	while (*v) {
+		count2++;
+		v++;
+	}
+	v = xrealloc(strings, (count1 + count2 + 1) * sizeof(char*));
+	v[count1 + count2] = NULL;
+	i = count2;
+	while (--i >= 0)
+		v[count1 + i] = (need_to_dup ? xstrdup(add[i]) : add[i]);
+	return v;
+}
+#if LEAK_HUNTING
+static char **xx_add_strings_to_strings(int lineno, char **strings, char **add, int need_to_dup)
+{
+	char **ptr = add_strings_to_strings(strings, add, need_to_dup);
+	fdprintf(2, "line %d: add_strings_to_strings %p\n", lineno, ptr);
+	return ptr;
+}
+#define add_strings_to_strings(strings, add, need_to_dup) \
+	xx_add_strings_to_strings(__LINE__, strings, add, need_to_dup)
+#endif
+
+/* Note: takes ownership of "add" ptr (it is not strdup'ed) */
+static char **add_string_to_strings(char **strings, char *add)
+{
+	char *v[2];
+	v[0] = add;
+	v[1] = NULL;
+	return add_strings_to_strings(strings, v, /*dup:*/ 0);
+}
+#if LEAK_HUNTING
+static char **xx_add_string_to_strings(int lineno, char **strings, char *add)
+{
+	char **ptr = add_string_to_strings(strings, add);
+	fdprintf(2, "line %d: add_string_to_strings %p\n", lineno, ptr);
+	return ptr;
+}
+#define add_string_to_strings(strings, add) \
+	xx_add_string_to_strings(__LINE__, strings, add)
+#endif
+
+static void free_strings(char **strings)
+{
+	char **v;
+
+	if (!strings)
+		return;
+	v = strings;
+	while (*v) {
+		free(*v);
+		v++;
+	}
+	free(strings);
+}
+
+static int dup_CLOEXEC(int fd, int avoid_fd)
+{
+	int newfd;
+ repeat:
+	newfd = fcntl(fd, F_DUPFD_CLOEXEC, avoid_fd + 1);
+	if (newfd >= 0) {
+		if (F_DUPFD_CLOEXEC == F_DUPFD) /* if old libc (w/o F_DUPFD_CLOEXEC) */
+			fcntl(newfd, F_SETFD, FD_CLOEXEC);
+	} else { /* newfd < 0 */
+		if (errno == EBUSY)
+			goto repeat;
+		if (errno == EINTR)
+			goto repeat;
+	}
+	return newfd;
+}
+
+static int xdup_CLOEXEC_and_close(int fd, int avoid_fd)
+{
+	int newfd;
+ repeat:
+	newfd = fcntl(fd, F_DUPFD_CLOEXEC, avoid_fd + 1);
+	if (newfd < 0) {
+		if (errno == EBUSY)
+			goto repeat;
+		if (errno == EINTR)
+			goto repeat;
+		/* fd was not open? */
+		if (errno == EBADF)
+			return fd;
+		xfunc_die();
+	}
+	if (F_DUPFD_CLOEXEC == F_DUPFD) /* if old libc (w/o F_DUPFD_CLOEXEC) */
+		fcntl(newfd, F_SETFD, FD_CLOEXEC);
+	close(fd);
+	return newfd;
+}
+
+
+/* Manipulating HFILEs */
+static HFILE *hfopen(const char *name)
+{
+	HFILE *fp;
+	int fd;
+
+	fd = STDIN_FILENO;
+	if (name) {
+		fd = open(name, O_RDONLY | O_CLOEXEC);
+		if (fd < 0)
+			return NULL;
+		if (O_CLOEXEC == 0) /* ancient libc */
+			close_on_exec_on(fd);
+	}
+
+	fp = xmalloc(sizeof(*fp));
+	if (name == NULL)
+		G.HFILE_stdin = fp;
+	fp->fd = fd;
+	fp->cur = fp->end = fp->buf;
+	fp->next_hfile = G.HFILE_list;
+	G.HFILE_list = fp;
+	return fp;
+}
+static void hfclose(HFILE *fp)
+{
+	HFILE **pp = &G.HFILE_list;
+	while (*pp) {
+		HFILE *cur = *pp;
+		if (cur == fp) {
+			*pp = cur->next_hfile;
+			break;
+		}
+		pp = &cur->next_hfile;
+	}
+	if (fp->fd >= 0)
+		close(fp->fd);
+	free(fp);
+}
+static int refill_HFILE_and_getc(HFILE *fp)
+{
+	int n;
+
+	if (fp->fd < 0) {
+		/* Already saw EOF */
+		return EOF;
+	}
+#if ENABLE_HUSH_INTERACTIVE && !ENABLE_FEATURE_EDITING
+	/* If user presses ^C, read() restarts after SIGINT (we use SA_RESTART).
+	 * IOW: ^C will not immediately stop line input.
+	 * But poll() is different: it does NOT restart after signals.
+	 */
+	if (fp == G.HFILE_stdin) {
+		struct pollfd pfd[1];
+		pfd[0].fd = fp->fd;
+		pfd[0].events = POLLIN;
+		n = poll(pfd, 1, -1);
+		if (n < 0
+		 /*&& errno == EINTR - assumed true */
+		 && sigismember(&G.pending_set, SIGINT)
+		) {
+			return '\0';
+		}
+	}
+#else
+/* if FEATURE_EDITING=y, we do not use this routine for interactive input */
+#endif
+	/* Try to buffer more input */
+	n = safe_read(fp->fd, fp->buf, sizeof(fp->buf));
+	if (n < 0) {
+		bb_simple_perror_msg("read error");
+		n = 0;
+	}
+	fp->cur = fp->buf;
+	fp->end = fp->buf + n;
+	if (n == 0) {
+		/* EOF/error */
+		close(fp->fd);
+		fp->fd = -1;
+		return EOF;
+	}
+	return (unsigned char)(*fp->cur++);
+}
+/* Inlined for common case of non-empty buffer.
+ */
+static ALWAYS_INLINE int hfgetc(HFILE *fp)
+{
+	if (fp->cur < fp->end)
+		return (unsigned char)(*fp->cur++);
+	/* Buffer empty */
+	return refill_HFILE_and_getc(fp);
+}
+static int move_HFILEs_on_redirect(int fd, int avoid_fd)
+{
+	HFILE *fl = G.HFILE_list;
+	while (fl) {
+		if (fd == fl->fd) {
+			/* We use it only on script files, they are all CLOEXEC */
+			fl->fd = xdup_CLOEXEC_and_close(fd, avoid_fd);
+			debug_printf_redir("redirect_fd %d: matches a script fd, moving it to %d\n", fd, fl->fd);
+			return 1; /* "found and moved" */
+		}
+		fl = fl->next_hfile;
+	}
+#if ENABLE_HUSH_MODE_X
+	if (G.x_mode_fd > 0 && fd == G.x_mode_fd) {
+		G.x_mode_fd = xdup_CLOEXEC_and_close(fd, avoid_fd);
+		return 1; /* "found and moved" */
+	}
+#endif
+	return 0; /* "not in the list" */
+}
+#if ENABLE_FEATURE_SH_STANDALONE && BB_MMU
+static void close_all_HFILE_list(void)
+{
+	HFILE *fl = G.HFILE_list;
+	while (fl) {
+		/* hfclose would also free HFILE object.
+		 * It is disastrous if we share memory with a vforked parent.
+		 * I'm not sure we never come here after vfork.
+		 * Therefore just close fd, nothing more.
+		 *
+		 * ">" instead of ">=": we don't close fd#0,
+		 * interactive shell uses hfopen(NULL) as stdin input
+		 * which has fl->fd == 0, but fd#0 gets redirected in pipes.
+		 * If we'd close it here, then e.g. interactive "set | sort"
+		 * with NOFORKed sort, would have sort's input fd closed.
+		 */
+		if (fl->fd > 0)
+			/*hfclose(fl); - unsafe */
+			close(fl->fd);
+		fl = fl->next_hfile;
+	}
+}
+#endif
+static int fd_in_HFILEs(int fd)
+{
+	HFILE *fl = G.HFILE_list;
+	while (fl) {
+		if (fl->fd == fd)
+			return 1;
+		fl = fl->next_hfile;
+	}
+	return 0;
+}
+
+
+/* Helpers for setting new $n and restoring them back
+ */
+typedef struct save_arg_t {
+	char *sv_argv0;
+	char **sv_g_argv;
+	int sv_g_argc;
+	IF_HUSH_SET(smallint sv_g_malloced;)
+} save_arg_t;
+
+static void save_and_replace_G_args(save_arg_t *sv, char **argv)
+{
+	sv->sv_argv0 = argv[0];
+	sv->sv_g_argv = G.global_argv;
+	sv->sv_g_argc = G.global_argc;
+	IF_HUSH_SET(sv->sv_g_malloced = G.global_args_malloced;)
+
+	argv[0] = G.global_argv[0]; /* retain $0 */
+	G.global_argv = argv;
+	IF_HUSH_SET(G.global_args_malloced = 0;)
+
+	G.global_argc = 1 + string_array_len(argv + 1);
+}
+
+static void restore_G_args(save_arg_t *sv, char **argv)
+{
+#if ENABLE_HUSH_SET
+	if (G.global_args_malloced) {
+		/* someone ran "set -- arg1 arg2 ...", undo */
+		char **pp = G.global_argv;
+		while (*++pp) /* note: does not free $0 */
+			free(*pp);
+		free(G.global_argv);
+	}
+#endif
+	argv[0] = sv->sv_argv0;
+	G.global_argv = sv->sv_g_argv;
+	G.global_argc = sv->sv_g_argc;
+	IF_HUSH_SET(G.global_args_malloced = sv->sv_g_malloced;)
+}
+
+
+/* Basic theory of signal handling in shell
+ * ========================================
+ * This does not describe what hush does, rather, it is current understanding
+ * what it _should_ do. If it doesn't, it's a bug.
+ * http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#trap
+ *
+ * Signals are handled only after each pipe ("cmd | cmd | cmd" thing)
+ * is finished or backgrounded. It is the same in interactive and
+ * non-interactive shells, and is the same regardless of whether
+ * a user trap handler is installed or a shell special one is in effect.
+ * ^C or ^Z from keyboard seems to execute "at once" because it usually
+ * backgrounds (i.e. stops) or kills all members of currently running
+ * pipe.
+ *
+ * Wait builtin is interruptible by signals for which user trap is set
+ * or by SIGINT in interactive shell.
+ *
+ * Trap handlers will execute even within trap handlers. (right?)
+ *
+ * User trap handlers are forgotten when subshell ("(cmd)") is entered,
+ * except for handlers set to '' (empty string).
+ *
+ * If job control is off, backgrounded commands ("cmd &")
+ * have SIGINT, SIGQUIT set to SIG_IGN.
+ *
+ * Commands which are run in command substitution ("`cmd`")
+ * have SIGTTIN, SIGTTOU, SIGTSTP set to SIG_IGN.
+ *
+ * Ordinary commands have signals set to SIG_IGN/DFL as inherited
+ * by the shell from its parent.
+ *
+ * Signals which differ from SIG_DFL action
+ * (note: child (i.e., [v]forked) shell is not an interactive shell):
+ *
+ * SIGQUIT: ignore
+ * SIGTERM (interactive): ignore
+ * SIGHUP (interactive):
+ *    send SIGCONT to stopped jobs, send SIGHUP to all jobs and exit
+ * SIGTTIN, SIGTTOU, SIGTSTP (if job control is on): ignore
+ *    Note that ^Z is handled not by trapping SIGTSTP, but by seeing
+ *    that all pipe members are stopped. Try this in bash:
+ *    while :; do :; done - ^Z does not background it
+ *    (while :; do :; done) - ^Z backgrounds it
+ * SIGINT (interactive): wait for last pipe, ignore the rest
+ *    of the command line, show prompt. NB: ^C does not send SIGINT
+ *    to interactive shell while shell is waiting for a pipe,
+ *    since shell is bg'ed (is not in foreground process group).
+ *    Example 1: this waits 5 sec, but does not execute ls:
+ *    "echo $$; sleep 5; ls -l" + "kill -INT <pid>"
+ *    Example 2: this does not wait and does not execute ls:
+ *    "echo $$; sleep 5 & wait; ls -l" + "kill -INT <pid>"
+ *    Example 3: this does not wait 5 sec, but executes ls:
+ *    "sleep 5; ls -l" + press ^C
+ *    Example 4: this does not wait and does not execute ls:
+ *    "sleep 5 & wait; ls -l" + press ^C
+ *
+ * (What happens to signals which are IGN on shell start?)
+ * (What happens with signal mask on shell start?)
+ *
+ * Old implementation
+ * ==================
+ * We use in-kernel pending signal mask to determine which signals were sent.
+ * We block all signals which we don't want to take action immediately,
+ * i.e. we block all signals which need to have special handling as described
+ * above, and all signals which have traps set.
+ * After each pipe execution, we extract any pending signals via sigtimedwait()
+ * and act on them.
+ *
+ * unsigned special_sig_mask: a mask of such "special" signals
+ * sigset_t blocked_set:  current blocked signal set
+ *
+ * "trap - SIGxxx":
+ *    clear bit in blocked_set unless it is also in special_sig_mask
+ * "trap 'cmd' SIGxxx":
+ *    set bit in blocked_set (even if 'cmd' is '')
+ * after [v]fork, if we plan to be a shell:
+ *    unblock signals with special interactive handling
+ *    (child shell is not interactive),
+ *    unset all traps except '' (note: regardless of child shell's type - {}, (), etc)
+ * after [v]fork, if we plan to exec:
+ *    POSIX says fork clears pending signal mask in child - no need to clear it.
+ *    Restore blocked signal set to one inherited by shell just prior to exec.
+ *
+ * Note: as a result, we do not use signal handlers much. The only uses
+ * are to count SIGCHLDs
+ * and to restore tty pgrp on signal-induced exit.
+ *
+ * Note 2 (compat):
+ * Standard says "When a subshell is entered, traps that are not being ignored
+ * are set to the default actions". bash interprets it so that traps which
+ * are set to '' (ignore) are NOT reset to defaults. We do the same.
+ *
+ * Problem: the above approach makes it unwieldy to catch signals while
+ * we are in read builtin, or while we read commands from stdin:
+ * masked signals are not visible!
+ *
+ * New implementation
+ * ==================
+ * We record each signal we are interested in by installing signal handler
+ * for them - a bit like emulating kernel pending signal mask in userspace.
+ * We are interested in: signals which need to have special handling
+ * as described above, and all signals which have traps set.
+ * Signals are recorded in pending_set.
+ * After each pipe execution, we extract any pending signals
+ * and act on them.
+ *
+ * unsigned special_sig_mask: a mask of shell-special signals.
+ * unsigned fatal_sig_mask: a mask of signals on which we restore tty pgrp.
+ * char *traps[sig] if trap for sig is set (even if it's '').
+ * sigset_t pending_set: set of sigs we received.
+ *
+ * "trap - SIGxxx":
+ *    if sig is in special_sig_mask, set handler back to:
+ *        record_pending_signo, or to IGN if it's a tty stop signal
+ *    if sig is in fatal_sig_mask, set handler back to sigexit.
+ *    else: set handler back to SIG_DFL
+ * "trap 'cmd' SIGxxx":
+ *    set handler to record_pending_signo.
+ * "trap '' SIGxxx":
+ *    set handler to SIG_IGN.
+ * after [v]fork, if we plan to be a shell:
+ *    set signals with special interactive handling to SIG_DFL
+ *    (because child shell is not interactive),
+ *    unset all traps except '' (note: regardless of child shell's type - {}, (), etc)
+ * after [v]fork, if we plan to exec:
+ *    POSIX says fork clears pending signal mask in child - no need to clear it.
+ *
+ * To make wait builtin interruptible, we handle SIGCHLD as special signal,
+ * otherwise (if we leave it SIG_DFL) sigsuspend in wait builtin will not wake up on it.
+ *
+ * Note (compat):
+ * Standard says "When a subshell is entered, traps that are not being ignored
+ * are set to the default actions". bash interprets it so that traps which
+ * are set to '' (ignore) are NOT reset to defaults. We do the same.
+ */
+enum {
+	SPECIAL_INTERACTIVE_SIGS = 0
+		| (1 << SIGTERM)
+		| (1 << SIGINT)
+		| (1 << SIGHUP)
+		,
+	SPECIAL_JOBSTOP_SIGS = 0
+#if ENABLE_HUSH_JOB
+		| (1 << SIGTTIN)
+		| (1 << SIGTTOU)
+		| (1 << SIGTSTP)
+#endif
+		,
+};
+
+static void record_pending_signo(int sig)
+{
+	sigaddset(&G.pending_set, sig);
+#if ENABLE_HUSH_FAST
+	if (sig == SIGCHLD) {
+		G.count_SIGCHLD++;
+//bb_error_msg("[%d] SIGCHLD_handler: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD);
+	}
+#endif
+}
+
+static sighandler_t install_sighandler(int sig, sighandler_t handler)
+{
+	struct sigaction old_sa;
+
+	/* We could use signal() to install handlers... almost:
+	 * except that we need to mask ALL signals while handlers run.
+	 * I saw signal nesting in strace, race window isn't small.
+	 * SA_RESTART is also needed, but in Linux, signal()
+	 * sets SA_RESTART too.
+	 */
+	/* memset(&G.sa, 0, sizeof(G.sa)); - already done */
+	/* sigfillset(&G.sa.sa_mask);      - already done */
+	/* G.sa.sa_flags = SA_RESTART;     - already done */
+	G.sa.sa_handler = handler;
+	sigaction(sig, &G.sa, &old_sa);
+	return old_sa.sa_handler;
+}
+
+static void hush_exit(int exitcode) NORETURN;
+
+static void restore_ttypgrp_and__exit(void) NORETURN;
+static void restore_ttypgrp_and__exit(void)
+{
+	/* xfunc has failed! die die die */
+	/* no EXIT traps, this is an escape hatch! */
+	G.exiting = 1;
+	hush_exit(xfunc_error_retval);
+}
+
+#if ENABLE_HUSH_JOB
+
+/* Needed only on some libc:
+ * It was observed that on exit(), fgetc'ed buffered data
+ * gets "unwound" via lseek(fd, -NUM, SEEK_CUR).
+ * With the net effect that even after fork(), not vfork(),
+ * exit() in NOEXECed applet in "sh SCRIPT":
+ *	noexec_applet_here
+ *	echo END_OF_SCRIPT
+ * lseeks fd in input FILE object from EOF to "e" in "echo END_OF_SCRIPT".
+ * This makes "echo END_OF_SCRIPT" executed twice.
+ * Similar problems can be seen with msg_and_die_if_script() -> xfunc_die()
+ * and in `cmd` handling.
+ * If set as die_func(), this makes xfunc_die() exit via _exit(), not exit():
+ */
+static void fflush_and__exit(void) NORETURN;
+static void fflush_and__exit(void)
+{
+	fflush_all();
+	_exit(xfunc_error_retval);
+}
+
+/* After [v]fork, in child: do not restore tty pgrp on xfunc death */
+# define disable_restore_tty_pgrp_on_exit() (die_func = fflush_and__exit)
+/* After [v]fork, in parent: restore tty pgrp on xfunc death */
+# define enable_restore_tty_pgrp_on_exit()  (die_func = restore_ttypgrp_and__exit)
+
+/* Restores tty foreground process group, and exits.
+ * May be called as signal handler for fatal signal
+ * (will resend signal to itself, producing correct exit state)
+ * or called directly with -EXITCODE.
+ * We also call it if xfunc is exiting.
+ */
+static void sigexit(int sig) NORETURN;
+static void sigexit(int sig)
+{
+	/* Careful: we can end up here after [v]fork. Do not restore
+	 * tty pgrp then, only top-level shell process does that */
+	if (G_saved_tty_pgrp && getpid() == G.root_pid) {
+		/* Disable all signals: job control, SIGPIPE, etc.
+		 * Mostly paranoid measure, to prevent infinite SIGTTOU.
+		 */
+		sigprocmask_allsigs(SIG_BLOCK);
+		tcsetpgrp(G_interactive_fd, G_saved_tty_pgrp);
+	}
+
+	/* Not a signal, just exit */
+	if (sig <= 0)
+		_exit(- sig);
+
+	kill_myself_with_sig(sig); /* does not return */
+}
+#else
+
+# define disable_restore_tty_pgrp_on_exit() ((void)0)
+# define enable_restore_tty_pgrp_on_exit()  ((void)0)
+
+#endif
+
+static sighandler_t pick_sighandler(unsigned sig)
+{
+	sighandler_t handler = SIG_DFL;
+	if (sig < sizeof(unsigned)*8) {
+		unsigned sigmask = (1 << sig);
+
+#if ENABLE_HUSH_JOB
+		/* is sig fatal? */
+		if (G_fatal_sig_mask & sigmask)
+			handler = sigexit;
+		else
+#endif
+		/* sig has special handling? */
+		if (G.special_sig_mask & sigmask) {
+			handler = record_pending_signo;
+			/* TTIN/TTOU/TSTP can't be set to record_pending_signo
+			 * in order to ignore them: they will be raised
+			 * in an endless loop when we try to do some
+			 * terminal ioctls! We do have to _ignore_ these.
+			 */
+			if (SPECIAL_JOBSTOP_SIGS & sigmask)
+				handler = SIG_IGN;
+		}
+	}
+	return handler;
+}
+
+/* Restores tty foreground process group, and exits. */
+static void hush_exit(int exitcode)
+{
+#if ENABLE_FEATURE_EDITING_SAVE_ON_EXIT
+	save_history(G.line_input_state); /* may be NULL */
+#endif
+
+	fflush_all();
+	if (G.exiting <= 0 && G_traps && G_traps[0] && G_traps[0][0]) {
+		char *argv[3];
+		/* argv[0] is unused */
+		argv[1] = xstrdup(G_traps[0]); /* copy, since EXIT trap handler may modify G_traps[0] */
+		argv[2] = NULL;
+		G.exiting = 1; /* prevent EXIT trap recursion */
+		/* Note: G_traps[0] is not cleared!
+		 * "trap" will still show it, if executed
+		 * in the handler */
+		builtin_eval(argv);
+	}
+
+#if ENABLE_FEATURE_CLEAN_UP
+	{
+		struct variable *cur_var;
+		if (G.cwd != bb_msg_unknown)
+			free((char*)G.cwd);
+		cur_var = G.top_var;
+		while (cur_var) {
+			struct variable *tmp = cur_var;
+			if (!cur_var->max_len)
+				free(cur_var->varstr);
+			cur_var = cur_var->next;
+			free(tmp);
+		}
+	}
+#endif
+
+	fflush_all();
+#if ENABLE_HUSH_JOB
+	sigexit(- (exitcode & 0xff));
+#else
+	_exit(exitcode);
+#endif
+}
+
+//TODO: return a mask of ALL handled sigs?
+static int check_and_run_traps(void)
+{
+	int last_sig = 0;
+
+	while (1) {
+		int sig;
+
+		if (sigisemptyset(&G.pending_set))
+			break;
+		sig = 0;
+		do {
+			sig++;
+			if (sigismember(&G.pending_set, sig)) {
+				sigdelset(&G.pending_set, sig);
+				goto got_sig;
+			}
+		} while (sig < NSIG);
+		break;
+ got_sig:
+#if ENABLE_HUSH_TRAP
+		if (G_traps && G_traps[sig]) {
+			debug_printf_exec("%s: sig:%d handler:'%s'\n", __func__, sig, G.traps[sig]);
+			if (G_traps[sig][0]) {
+				/* We have user-defined handler */
+				smalluint save_rcode;
+				int save_pre;
+				char *argv[3];
+				/* argv[0] is unused */
+				argv[1] = xstrdup(G_traps[sig]);
+				/* why strdup? trap can modify itself: trap 'trap "echo oops" INT' INT */
+				argv[2] = NULL;
+				save_pre = G.pre_trap_exitcode;
+				G.pre_trap_exitcode = save_rcode = G.last_exitcode;
+				builtin_eval(argv);
+				free(argv[1]);
+				G.pre_trap_exitcode = save_pre;
+				G.last_exitcode = save_rcode;
+# if ENABLE_HUSH_FUNCTIONS
+				if (G.return_exitcode >= 0) {
+					debug_printf_exec("trap exitcode:%d\n", G.return_exitcode);
+					G.last_exitcode = G.return_exitcode;
+				}
+# endif
+				last_sig = sig;
+			} /* else: "" trap, ignoring signal */
+			continue;
+		}
+#endif
+		/* not a trap: special action */
+		switch (sig) {
+		case SIGINT:
+			debug_printf_exec("%s: sig:%d default SIGINT handler\n", __func__, sig);
+			G.flag_SIGINT = 1;
+			last_sig = sig;
+			break;
+#if ENABLE_HUSH_JOB
+		case SIGHUP: {
+//TODO: why are we doing this? ash and dash don't do this,
+//they have no handler for SIGHUP at all,
+//they rely on kernel to send SIGHUP+SIGCONT to orphaned process groups
+			struct pipe *job;
+			debug_printf_exec("%s: sig:%d default SIGHUP handler\n", __func__, sig);
+			/* bash is observed to signal whole process groups,
+			 * not individual processes */
+			for (job = G.job_list; job; job = job->next) {
+				if (job->pgrp <= 0)
+					continue;
+				debug_printf_exec("HUPing pgrp %d\n", job->pgrp);
+				if (kill(- job->pgrp, SIGHUP) == 0)
+					kill(- job->pgrp, SIGCONT);
+			}
+			sigexit(SIGHUP);
+		}
+#endif
+#if ENABLE_HUSH_FAST
+		case SIGCHLD:
+			debug_printf_exec("%s: sig:%d default SIGCHLD handler\n", __func__, sig);
+			G.count_SIGCHLD++;
+//bb_error_msg("[%d] check_and_run_traps: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD);
+			/* Note:
+			 * We don't do 'last_sig = sig' here -> NOT returning this sig.
+			 * This simplifies wait builtin a bit.
+			 */
+			break;
+#endif
+		default: /* ignored: */
+			debug_printf_exec("%s: sig:%d default handling is to ignore\n", __func__, sig);
+			/* SIGTERM, SIGQUIT, SIGTTIN, SIGTTOU, SIGTSTP */
+			/* Note:
+			 * We don't do 'last_sig = sig' here -> NOT returning this sig.
+			 * Example: wait is not interrupted by TERM
+			 * in interactive shell, because TERM is ignored.
+			 */
+			break;
+		}
+	}
+	return last_sig;
+}
+
+
+static const char *get_cwd(int force)
+{
+	if (force || G.cwd == NULL) {
+		/* xrealloc_getcwd_or_warn(arg) calls free(arg),
+		 * we must not try to free(bb_msg_unknown) */
+		if (G.cwd == bb_msg_unknown)
+			G.cwd = NULL;
+		G.cwd = xrealloc_getcwd_or_warn((char *)G.cwd);
+		if (!G.cwd)
+			G.cwd = bb_msg_unknown;
+	}
+	return G.cwd;
+}
+
+
+/*
+ * Shell and environment variable support
+ */
+static struct variable **get_ptr_to_local_var(const char *name, unsigned len)
+{
+	struct variable **pp;
+	struct variable *cur;
+
+	pp = &G.top_var;
+	while ((cur = *pp) != NULL) {
+		if (strncmp(cur->varstr, name, len) == 0 && cur->varstr[len] == '=')
+			return pp;
+		pp = &cur->next;
+	}
+	return NULL;
+}
+
+static const char* FAST_FUNC get_local_var_value(const char *name)
+{
+	struct variable **vpp;
+	unsigned len = strlen(name);
+
+	if (G.expanded_assignments) {
+		char **cpp = G.expanded_assignments;
+		while (*cpp) {
+			char *cp = *cpp;
+			if (strncmp(cp, name, len) == 0 && cp[len] == '=')
+				return cp + len + 1;
+			cpp++;
+		}
+	}
+
+	vpp = get_ptr_to_local_var(name, len);
+	if (vpp)
+		return (*vpp)->varstr + len + 1;
+
+	if (strcmp(name, "PPID") == 0)
+		return utoa(G.root_ppid);
+	// bash compat: UID? EUID?
+#if ENABLE_HUSH_RANDOM_SUPPORT
+	if (strcmp(name, "RANDOM") == 0)
+		return utoa(next_random(&G.random_gen));
+#endif
+#if ENABLE_HUSH_LINENO_VAR
+	if (strcmp(name, "LINENO") == 0)
+		return utoa(G.execute_lineno);
+#endif
+#if BASH_EPOCH_VARS
+	{
+		const char *fmt = NULL;
+		if (strcmp(name, "EPOCHSECONDS") == 0)
+			fmt = "%llu";
+		else if (strcmp(name, "EPOCHREALTIME") == 0)
+			fmt = "%llu.%06u";
+		if (fmt) {
+			struct timeval tv;
+			xgettimeofday(&tv);
+			sprintf(G.epoch_buf, fmt, (unsigned long long)tv.tv_sec,
+					(unsigned)tv.tv_usec);
+			return G.epoch_buf;
+		}
+	}
+#endif
+	return NULL;
+}
+
+#if ENABLE_HUSH_GETOPTS
+static void handle_changed_special_names(const char *name, unsigned name_len)
+{
+	if (name_len == 6) {
+		if (strncmp(name, "OPTIND", 6) == 0) {
+			G.getopt_count = 0;
+			return;
+		}
+	}
+}
+#else
+/* Do not even bother evaluating arguments */
+# define handle_changed_special_names(...) ((void)0)
+#endif
+
+/* str holds "NAME=VAL" and is expected to be malloced.
+ * We take ownership of it.
+ */
+#define SETFLAG_EXPORT   (1 << 0)
+#define SETFLAG_UNEXPORT (1 << 1)
+#define SETFLAG_MAKE_RO  (1 << 2)
+#define SETFLAG_VARLVL_SHIFT   3
+static int set_local_var(char *str, unsigned flags)
+{
+	struct variable **cur_pp;
+	struct variable *cur;
+	char *free_me = NULL;
+	char *eq_sign;
+	int name_len;
+	int retval;
+	unsigned local_lvl = (flags >> SETFLAG_VARLVL_SHIFT);
+
+	eq_sign = strchr(str, '=');
+	if (HUSH_DEBUG && !eq_sign)
+		bb_simple_error_msg_and_die("BUG in setvar");
+
+	name_len = eq_sign - str + 1; /* including '=' */
+	cur_pp = &G.top_var;
+	while ((cur = *cur_pp) != NULL) {
+		if (strncmp(cur->varstr, str, name_len) != 0) {
+			cur_pp = &cur->next;
+			continue;
+		}
+
+		/* We found an existing var with this name */
+		if (cur->flg_read_only) {
+			bb_error_msg("%s: readonly variable", str);
+			free(str);
+//NOTE: in bash, assignment in "export READONLY_VAR=Z" fails, and sets $?=1,
+//but export per se succeeds (does put the var in env). We don't mimic that.
+			return -1;
+		}
+		if (flags & SETFLAG_UNEXPORT) { // && cur->flg_export ?
+			debug_printf_env("%s: unsetenv '%s'\n", __func__, str);
+			*eq_sign = '\0';
+			unsetenv(str);
+			*eq_sign = '=';
+		}
+		if (cur->var_nest_level < local_lvl) {
+			/* bash 3.2.33(1) and exported vars:
+			 * # export z=z
+			 * # f() { local z=a; env | grep ^z; }
+			 * # f
+			 * z=a
+			 * # env | grep ^z
+			 * z=z
+			 */
+			if (cur->flg_export)
+				flags |= SETFLAG_EXPORT;
+			/* New variable is local ("local VAR=VAL" or
+			 * "VAR=VAL cmd")
+			 * and existing one is global, or local
+			 * on a lower level that new one.
+			 * Remove it from global variable list:
+			 */
+			*cur_pp = cur->next;
+			if (G.shadowed_vars_pp) {
+				/* Save in "shadowed" list */
+				debug_printf_env("shadowing %s'%s'/%u by '%s'/%u\n",
+					cur->flg_export ? "exported " : "",
+					cur->varstr, cur->var_nest_level, str, local_lvl
+				);
+				cur->next = *G.shadowed_vars_pp;
+				*G.shadowed_vars_pp = cur;
+			} else {
+				/* Came from pseudo_exec_argv(), no need to save: delete it */
+				debug_printf_env("shadow-deleting %s'%s'/%u by '%s'/%u\n",
+					cur->flg_export ? "exported " : "",
+					cur->varstr, cur->var_nest_level, str, local_lvl
+				);
+				if (cur->max_len == 0) /* allocated "VAR=VAL"? */
+					free_me = cur->varstr; /* then free it later */
+				free(cur);
+			}
+			break;
+		}
+
+		if (strcmp(cur->varstr + name_len, eq_sign + 1) == 0) {
+			debug_printf_env("assignement '%s' does not change anything\n", str);
+ free_and_exp:
+			free(str);
+			goto exp;
+		}
+
+		/* Replace the value in the found "struct variable" */
+		if (cur->max_len != 0) {
+			if (cur->max_len >= strnlen(str, cur->max_len + 1)) {
+				/* This one is from startup env, reuse space */
+				debug_printf_env("reusing startup env for '%s'\n", str);
+				strcpy(cur->varstr, str);
+				goto free_and_exp;
+			}
+			/* Can't reuse */
+			cur->max_len = 0;
+			goto set_str_and_exp;
+		}
+		/* max_len == 0 signifies "malloced" var, which we can
+		 * (and have to) free. But we can't free(cur->varstr) here:
+		 * if cur->flg_export is 1, it is in the environment.
+		 * We should either unsetenv+free, or wait until putenv,
+		 * then putenv(new)+free(old).
+		 */
+		free_me = cur->varstr;
+		goto set_str_and_exp;
+	}
+
+	/* Not found or shadowed - create new variable struct */
+	debug_printf_env("%s: alloc new var '%s'/%u\n", __func__, str, local_lvl);
+	cur = xzalloc(sizeof(*cur));
+	cur->var_nest_level = local_lvl;
+	cur->next = *cur_pp;
+	*cur_pp = cur;
+
+ set_str_and_exp:
+	cur->varstr = str;
+ exp:
+#if !BB_MMU || ENABLE_HUSH_READONLY
+	if (flags & SETFLAG_MAKE_RO) {
+		cur->flg_read_only = 1;
+	}
+#endif
+	if (flags & SETFLAG_EXPORT)
+		cur->flg_export = 1;
+	retval = 0;
+	if (cur->flg_export) {
+		if (flags & SETFLAG_UNEXPORT) {
+			cur->flg_export = 0;
+			/* unsetenv was already done */
+		} else {
+			debug_printf_env("%s: putenv '%s'/%u\n", __func__, cur->varstr, cur->var_nest_level);
+			retval = putenv(cur->varstr);
+			/* fall through to "free(free_me)" -
+			 * only now we can free old exported malloced string
+			 */
+		}
+	}
+	free(free_me);
+
+	handle_changed_special_names(cur->varstr, name_len - 1);
+
+	return retval;
+}
+
+static void FAST_FUNC set_local_var_from_halves(const char *name, const char *val)
+{
+	char *var = xasprintf("%s=%s", name, val);
+	set_local_var(var, /*flag:*/ 0);
+}
+
+/* Used at startup and after each cd */
+static void set_pwd_var(unsigned flag)
+{
+	set_local_var(xasprintf("PWD=%s", get_cwd(/*force:*/ 1)), flag);
+}
+
+#if ENABLE_HUSH_UNSET || ENABLE_HUSH_GETOPTS
+static int unset_local_var_len(const char *name, int name_len)
+{
+	struct variable *cur;
+	struct variable **cur_pp;
+
+	cur_pp = &G.top_var;
+	while ((cur = *cur_pp) != NULL) {
+		if (strncmp(cur->varstr, name, name_len) == 0
+		 && cur->varstr[name_len] == '='
+		) {
+			if (cur->flg_read_only) {
+				bb_error_msg("%s: readonly variable", name);
+				return EXIT_FAILURE;
+			}
+
+			*cur_pp = cur->next;
+			debug_printf_env("%s: unsetenv '%s'\n", __func__, cur->varstr);
+			bb_unsetenv(cur->varstr);
+			if (!cur->max_len)
+				free(cur->varstr);
+			free(cur);
+
+			break;
+		}
+		cur_pp = &cur->next;
+	}
+
+	/* Handle "unset LINENO" et al even if did not find the variable to unset */
+	handle_changed_special_names(name, name_len);
+
+	return EXIT_SUCCESS;
+}
+
+static int unset_local_var(const char *name)
+{
+	return unset_local_var_len(name, strlen(name));
+}
+#endif
+
+
+/*
+ * Helpers for "var1=val1 var2=val2 cmd" feature
+ */
+static void add_vars(struct variable *var)
+{
+	struct variable *next;
+
+	while (var) {
+		next = var->next;
+		var->next = G.top_var;
+		G.top_var = var;
+		if (var->flg_export) {
+			debug_printf_env("%s: restoring exported '%s'/%u\n", __func__, var->varstr, var->var_nest_level);
+			putenv(var->varstr);
+		} else {
+			debug_printf_env("%s: restoring variable '%s'/%u\n", __func__, var->varstr, var->var_nest_level);
+		}
+		var = next;
+	}
+}
+
+/* We put strings[i] into variable table and possibly putenv them.
+ * If variable is read only, we can free the strings[i]
+ * which attempts to overwrite it.
+ * The strings[] vector itself is freed.
+ */
+static void set_vars_and_save_old(char **strings)
+{
+	char **s;
+
+	if (!strings)
+		return;
+
+	s = strings;
+	while (*s) {
+		struct variable *var_p;
+		struct variable **var_pp;
+		char *eq;
+
+		eq = strchr(*s, '=');
+		if (HUSH_DEBUG && !eq)
+			bb_simple_error_msg_and_die("BUG in varexp4");
+		var_pp = get_ptr_to_local_var(*s, eq - *s);
+		if (var_pp) {
+			var_p = *var_pp;
+			if (var_p->flg_read_only) {
+				char **p;
+				bb_error_msg("%s: readonly variable", *s);
+				/*
+				 * "VAR=V BLTIN" unsets VARs after BLTIN completes.
+				 * If VAR is readonly, leaving it in the list
+				 * after asssignment error (msg above)
+				 * causes doubled error message later, on unset.
+				 */
+				debug_printf_env("removing/freeing '%s' element\n", *s);
+				free(*s);
+				p = s;
+				do { *p = p[1]; p++; } while (*p);
+				goto next;
+			}
+			/* below, set_local_var() with nest level will
+			 * "shadow" (remove) this variable from
+			 * global linked list.
+			 */
+		}
+		debug_printf_env("%s: env override '%s'/%u\n", __func__, *s, G.var_nest_level);
+		set_local_var(*s, (G.var_nest_level << SETFLAG_VARLVL_SHIFT) | SETFLAG_EXPORT);
+		s++;
+ next: ;
+	}
+	free(strings);
+}
+
+
+/*
+ * Unicode helper
+ */
+static void reinit_unicode_for_hush(void)
+{
+	/* Unicode support should be activated even if LANG is set
+	 * _during_ shell execution, not only if it was set when
+	 * shell was started. Therefore, re-check LANG every time:
+	 */
+	if (ENABLE_FEATURE_CHECK_UNICODE_IN_ENV
+	 || ENABLE_UNICODE_USING_LOCALE
+	) {
+		const char *s = get_local_var_value("LC_ALL");
+		if (!s) s = get_local_var_value("LC_CTYPE");
+		if (!s) s = get_local_var_value("LANG");
+		reinit_unicode(s);
+	}
+}
+
+/*
+ * in_str support (strings, and "strings" read from files).
+ */
+
+#if ENABLE_HUSH_INTERACTIVE
+/* To test correct lineedit/interactive behavior, type from command line:
+ *	echo $P\
+ *	\
+ *	AT\
+ *	H\
+ *	\
+ * It exercises a lot of corner cases.
+ */
+static const char *setup_prompt_string(void)
+{
+	const char *prompt_str;
+
+	debug_printf_prompt("%s promptmode:%d\n", __func__, G.promptmode);
+
+# if ENABLE_FEATURE_EDITING_FANCY_PROMPT
+	prompt_str = get_local_var_value(G.promptmode == 0 ? "PS1" : "PS2");
+	if (!prompt_str)
+		prompt_str = "";
+# else
+	prompt_str = "> "; /* if PS2, else... */
+	if (G.promptmode == 0) { /* PS1 */
+		/* No fancy prompts supported, (re)generate "CURDIR $ " by hand */
+		free(G.PS1);
+		/* bash uses $PWD value, even if it is set by user.
+		 * It uses current dir only if PWD is unset.
+		 * We always use current dir. */
+		prompt_str = G.PS1 = xasprintf("%s %c ", get_cwd(0), (geteuid() != 0) ? '$' : '#');
+	}
+# endif
+	debug_printf("prompt_str '%s'\n", prompt_str);
+	return prompt_str;
+}
+static int get_user_input(struct in_str *i)
+{
+# if ENABLE_FEATURE_EDITING
+	/* In EDITING case, this function reads next input line,
+	 * saves it in i->p, then returns 1st char of it.
+	 */
+	int r;
+	const char *prompt_str;
+
+	prompt_str = setup_prompt_string();
+	for (;;) {
+		reinit_unicode_for_hush();
+		G.flag_SIGINT = 0;
+		/* buglet: SIGINT will not make new prompt to appear _at once_,
+		 * only after <Enter>. (^C works immediately) */
+		r = read_line_input(G.line_input_state, prompt_str,
+				G.user_input_buf, CONFIG_FEATURE_EDITING_MAX_LEN-1
+		);
+		/* read_line_input intercepts ^C, "convert" it to SIGINT */
+		if (r == 0) {
+			raise(SIGINT);
+		}
+		check_and_run_traps();
+		if (r != 0 && !G.flag_SIGINT)
+			break;
+		/* ^C or SIGINT: repeat */
+		/* bash prints ^C even on real SIGINT (non-kbd generated) */
+		write(STDOUT_FILENO, "^C\n", 3);
+		G.last_exitcode = 128 | SIGINT;
+	}
+	if (r < 0) {
+		/* EOF/error detected */
+		/* ^D on interactive input goes to next line before exiting: */
+		write(STDOUT_FILENO, "\n", 1);
+		i->p = NULL;
+		i->peek_buf[0] = r = EOF;
+		return r;
+	}
+	i->p = G.user_input_buf;
+	return (unsigned char)*i->p++;
+# else
+	/* In !EDITING case, this function gets called for every char.
+	 * Buffering happens deeper in the call chain, in hfgetc(i->file).
+	 */
+	int r;
+
+	for (;;) {
+		G.flag_SIGINT = 0;
+		if (i->last_char == '\0' || i->last_char == '\n') {
+			const char *prompt_str = setup_prompt_string();
+			/* Why check_and_run_traps here? Try this interactively:
+			 * $ trap 'echo INT' INT; (sleep 2; kill -INT $$) &
+			 * $ <[enter], repeatedly...>
+			 * Without check_and_run_traps, handler never runs.
+			 */
+			check_and_run_traps();
+			fputs_stdout(prompt_str);
+			fflush_all();
+		}
+		r = hfgetc(i->file);
+		/* In !ENABLE_FEATURE_EDITING we don't use read_line_input,
+		 * no ^C masking happens during fgetc, no special code for ^C:
+		 * it generates SIGINT as usual.
+		 */
+		check_and_run_traps();
+		if (r != '\0' && !G.flag_SIGINT)
+			break;
+		if (G.flag_SIGINT) {
+			/* ^C or SIGINT: repeat */
+			/* bash prints ^C even on real SIGINT (non-kbd generated) */
+			/* kernel prints "^C" itself, just print newline: */
+			write(STDOUT_FILENO, "\n", 1);
+			G.last_exitcode = 128 | SIGINT;
+		}
+	}
+	return r;
+# endif
+}
+/* This is the magic location that prints prompts
+ * and gets data back from the user */
+static int fgetc_interactive(struct in_str *i)
+{
+	int ch;
+	/* If it's interactive stdin, get new line. */
+	if (G_interactive_fd && i->file == G.HFILE_stdin) {
+		/* Returns first char (or EOF), the rest is in i->p[] */
+		ch = get_user_input(i);
+		G.promptmode = 1; /* PS2 */
+		debug_printf_prompt("%s promptmode=%d\n", __func__, G.promptmode);
+	} else {
+		/* Not stdin: script file, sourced file, etc */
+		do ch = hfgetc(i->file); while (ch == '\0');
+	}
+	return ch;
+}
+#else  /* !INTERACTIVE */
+static ALWAYS_INLINE int fgetc_interactive(struct in_str *i)
+{
+	int ch;
+	do ch = hfgetc(i->file); while (ch == '\0');
+	return ch;
+}
+#endif  /* !INTERACTIVE */
+
+static int i_getch(struct in_str *i)
+{
+	int ch;
+
+	if (!i->file) {
+		/* string-based in_str */
+		ch = (unsigned char)*i->p;
+		if (ch != '\0') {
+			i->p++;
+			i->last_char = ch;
+			return ch;
+		}
+		return EOF;
+	}
+
+	/* FILE-based in_str */
+
+#if ENABLE_FEATURE_EDITING
+	/* This can be stdin, check line editing char[] buffer */
+	if (i->p && *i->p != '\0') {
+		ch = (unsigned char)*i->p++;
+		goto out;
+	}
+#endif
+	/* peek_buf[] is an int array, not char. Can contain EOF. */
+	ch = i->peek_buf[0];
+	if (ch != 0) {
+		int ch2 = i->peek_buf[1];
+		i->peek_buf[0] = ch2;
+		if (ch2 == 0) /* very likely, avoid redundant write */
+			goto out;
+		i->peek_buf[1] = 0;
+		goto out;
+	}
+
+	ch = fgetc_interactive(i);
+ out:
+	debug_printf("file_get: got '%c' %d\n", ch, ch);
+	i->last_char = ch;
+#if ENABLE_HUSH_LINENO_VAR
+	if (ch == '\n') {
+		G.parse_lineno++;
+		debug_printf_parse("G.parse_lineno++ = %u\n", G.parse_lineno);
+	}
+#endif
+	return ch;
+}
+
+static int i_peek(struct in_str *i)
+{
+	int ch;
+
+	if (!i->file) {
+		/* string-based in_str */
+		/* Doesn't report EOF on NUL. None of the callers care. */
+		return (unsigned char)*i->p;
+	}
+
+	/* FILE-based in_str */
+
+#if ENABLE_FEATURE_EDITING && ENABLE_HUSH_INTERACTIVE
+	/* This can be stdin, check line editing char[] buffer */
+	if (i->p && *i->p != '\0')
+		return (unsigned char)*i->p;
+#endif
+	/* peek_buf[] is an int array, not char. Can contain EOF. */
+	ch = i->peek_buf[0];
+	if (ch != 0)
+		return ch;
+
+	/* Need to get a new char */
+	ch = fgetc_interactive(i);
+	debug_printf("file_peek: got '%c' %d\n", ch, ch);
+
+	/* Save it by either rolling back line editing buffer, or in i->peek_buf[0] */
+#if ENABLE_FEATURE_EDITING && ENABLE_HUSH_INTERACTIVE
+	if (i->p) {
+		i->p -= 1;
+		return ch;
+	}
+#endif
+	i->peek_buf[0] = ch;
+	/*i->peek_buf[1] = 0; - already is */
+	return ch;
+}
+
+/* Only ever called if i_peek() was called, and did not return EOF.
+ * IOW: we know the previous peek saw an ordinary char, not EOF, not NUL,
+ * not end-of-line. Therefore we never need to read a new editing line here.
+ */
+static int i_peek2(struct in_str *i)
+{
+	int ch;
+
+	/* There are two cases when i->p[] buffer exists.
+	 * (1) it's a string in_str.
+	 * (2) It's a file, and we have a saved line editing buffer.
+	 * In both cases, we know that i->p[0] exists and not NUL, and
+	 * the peek2 result is in i->p[1].
+	 */
+	if (i->p)
+		return (unsigned char)i->p[1];
+
+	/* Now we know it is a file-based in_str. */
+
+	/* peek_buf[] is an int array, not char. Can contain EOF. */
+	/* Is there 2nd char? */
+	ch = i->peek_buf[1];
+	if (ch == 0) {
+		/* We did not read it yet, get it now */
+		do ch = hfgetc(i->file); while (ch == '\0');
+		i->peek_buf[1] = ch;
+	}
+
+	debug_printf("file_peek2: got '%c' %d\n", ch, ch);
+	return ch;
+}
+
+static int i_getch_and_eat_bkslash_nl(struct in_str *input)
+{
+	for (;;) {
+		int ch, ch2;
+
+		ch = i_getch(input);
+		if (ch != '\\')
+			return ch;
+		ch2 = i_peek(input);
+		if (ch2 != '\n')
+			return ch;
+		/* backslash+newline, skip it */
+		i_getch(input);
+	}
+}
+
+/* Note: this function _eats_ \<newline> pairs, safe to use plain
+ * i_getch() after it instead of i_getch_and_eat_bkslash_nl().
+ */
+static int i_peek_and_eat_bkslash_nl(struct in_str *input)
+{
+	for (;;) {
+		int ch, ch2;
+
+		ch = i_peek(input);
+		if (ch != '\\')
+			return ch;
+		ch2 = i_peek2(input);
+		if (ch2 != '\n')
+			return ch;
+		/* backslash+newline, skip it */
+		i_getch(input);
+		i_getch(input);
+	}
+}
+
+static void setup_file_in_str(struct in_str *i, HFILE *fp)
+{
+	memset(i, 0, sizeof(*i));
+	i->file = fp;
+	/* i->p = NULL; */
+}
+
+static void setup_string_in_str(struct in_str *i, const char *s)
+{
+	memset(i, 0, sizeof(*i));
+	/*i->file = NULL */;
+	i->p = s;
+}
+
+
+/*
+ * o_string support
+ */
+#define B_CHUNK  (32 * sizeof(char*))
+
+static void o_reset_to_empty_unquoted(o_string *o)
+{
+	o->length = 0;
+	o->has_quoted_part = 0;
+	if (o->data)
+		o->data[0] = '\0';
+}
+
+static void o_free_and_set_NULL(o_string *o)
+{
+	free(o->data);
+	memset(o, 0, sizeof(*o));
+}
+
+static ALWAYS_INLINE void o_free(o_string *o)
+{
+	free(o->data);
+}
+
+static void o_grow_by(o_string *o, int len)
+{
+	if (o->length + len > o->maxlen) {
+		o->maxlen += (2 * len) | (B_CHUNK-1);
+		o->data = xrealloc(o->data, 1 + o->maxlen);
+	}
+}
+
+static void o_addchr(o_string *o, int ch)
+{
+	debug_printf("o_addchr: '%c' o->length=%d o=%p\n", ch, o->length, o);
+	if (o->length < o->maxlen) {
+		/* likely. avoid o_grow_by() call */
+ add:
+		o->data[o->length] = ch;
+		o->length++;
+		o->data[o->length] = '\0';
+		return;
+	}
+	o_grow_by(o, 1);
+	goto add;
+}
+
+#if 0
+/* Valid only if we know o_string is not empty */
+static void o_delchr(o_string *o)
+{
+	o->length--;
+	o->data[o->length] = '\0';
+}
+#endif
+
+static void o_addblock(o_string *o, const char *str, int len)
+{
+	o_grow_by(o, len);
+	((char*)mempcpy(&o->data[o->length], str, len))[0] = '\0';
+	o->length += len;
+}
+
+static void o_addstr(o_string *o, const char *str)
+{
+	o_addblock(o, str, strlen(str));
+}
+
+static void o_addstr_with_NUL(o_string *o, const char *str)
+{
+	o_addblock(o, str, strlen(str) + 1);
+}
+
+#if !BB_MMU
+static void nommu_addchr(o_string *o, int ch)
+{
+	if (o)
+		o_addchr(o, ch);
+}
+#else
+# define nommu_addchr(o, str) ((void)0)
+#endif
+
+#if ENABLE_HUSH_MODE_X
+static void x_mode_addchr(int ch)
+{
+	o_addchr(&G.x_mode_buf, ch);
+}
+static void x_mode_addstr(const char *str)
+{
+	o_addstr(&G.x_mode_buf, str);
+}
+static void x_mode_addblock(const char *str, int len)
+{
+	o_addblock(&G.x_mode_buf, str, len);
+}
+static void x_mode_prefix(void)
+{
+	int n = G.x_mode_depth;
+	do x_mode_addchr('+'); while (--n >= 0);
+}
+static void x_mode_flush(void)
+{
+	int len = G.x_mode_buf.length;
+	if (len <= 0)
+		return;
+	if (G.x_mode_fd > 0) {
+		G.x_mode_buf.data[len] = '\n';
+		full_write(G.x_mode_fd, G.x_mode_buf.data, len + 1);
+	}
+	G.x_mode_buf.length = 0;
+}
+#endif
+
+/*
+ * HUSH_BRACE_EXPANSION code needs corresponding quoting on variable expansion side.
+ * Currently, "v='{q,w}'; echo $v" erroneously expands braces in $v.
+ * Apparently, on unquoted $v bash still does globbing
+ * ("v='*.txt'; echo $v" prints all .txt files),
+ * but NOT brace expansion! Thus, there should be TWO independent
+ * quoting mechanisms on $v expansion side: one protects
+ * $v from brace expansion, and other additionally protects "$v" against globbing.
+ * We have only second one.
+ */
+
+#if ENABLE_HUSH_BRACE_EXPANSION
+# define MAYBE_BRACES "{}"
+#else
+# define MAYBE_BRACES ""
+#endif
+
+/* My analysis of quoting semantics tells me that state information
+ * is associated with a destination, not a source.
+ */
+static void o_addqchr(o_string *o, int ch)
+{
+	int sz = 1;
+	/* '-' is included because of this case:
+	 * >filename0 >filename1 >filename9; v='-'; echo filename[0"$v"9]
+	 */
+	char *found = strchr("*?[-\\" MAYBE_BRACES, ch);
+	if (found)
+		sz++;
+	o_grow_by(o, sz);
+	if (found) {
+		o->data[o->length] = '\\';
+		o->length++;
+	}
+	o->data[o->length] = ch;
+	o->length++;
+	o->data[o->length] = '\0';
+}
+
+static void o_addQchr(o_string *o, int ch)
+{
+	int sz = 1;
+	if ((o->o_expflags & EXP_FLAG_ESC_GLOB_CHARS)
+	 && strchr("*?[-\\" MAYBE_BRACES, ch)
+	) {
+		sz++;
+		o->data[o->length] = '\\';
+		o->length++;
+	}
+	o_grow_by(o, sz);
+	o->data[o->length] = ch;
+	o->length++;
+	o->data[o->length] = '\0';
+}
+
+static void o_addqblock(o_string *o, const char *str, int len)
+{
+	while (len) {
+		char ch;
+		int sz;
+		int ordinary_cnt = strcspn(str, "*?[-\\" MAYBE_BRACES);
+		if (ordinary_cnt > len) /* paranoia */
+			ordinary_cnt = len;
+		o_addblock(o, str, ordinary_cnt);
+		if (ordinary_cnt == len)
+			return; /* NUL is already added by o_addblock */
+		str += ordinary_cnt;
+		len -= ordinary_cnt + 1; /* we are processing + 1 char below */
+
+		ch = *str++;
+		sz = 1;
+		if (ch) { /* it is necessarily one of "*?[-\\" MAYBE_BRACES */
+			sz++;
+			o->data[o->length] = '\\';
+			o->length++;
+		}
+		o_grow_by(o, sz);
+		o->data[o->length] = ch;
+		o->length++;
+	}
+	o->data[o->length] = '\0';
+}
+
+static void o_addQblock(o_string *o, const char *str, int len)
+{
+	if (!(o->o_expflags & EXP_FLAG_ESC_GLOB_CHARS)) {
+		o_addblock(o, str, len);
+		return;
+	}
+	o_addqblock(o, str, len);
+}
+
+static void o_addQstr(o_string *o, const char *str)
+{
+	o_addQblock(o, str, strlen(str));
+}
+
+/* A special kind of o_string for $VAR and `cmd` expansion.
+ * It contains char* list[] at the beginning, which is grown in 16 element
+ * increments. Actual string data starts at the next multiple of 16 * (char*).
+ * list[i] contains an INDEX (int!) into this string data.
+ * It means that if list[] needs to grow, data needs to be moved higher up
+ * but list[i]'s need not be modified.
+ * NB: remembering how many list[i]'s you have there is crucial.
+ * o_finalize_list() operation post-processes this structure - calculates
+ * and stores actual char* ptrs in list[]. Oh, it NULL terminates it as well.
+ */
+#if DEBUG_EXPAND || DEBUG_GLOB
+static void debug_print_list(const char *prefix, o_string *o, int n)
+{
+	char **list = (char**)o->data;
+	int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
+	int i = 0;
+
+	indent();
+	fdprintf(2, "%s: list:%p n:%d string_start:%d length:%d maxlen:%d glob:%d quoted:%d escape:%d\n",
+			prefix, list, n, string_start, o->length, o->maxlen,
+			!!(o->o_expflags & EXP_FLAG_GLOB),
+			o->has_quoted_part,
+			!!(o->o_expflags & EXP_FLAG_ESC_GLOB_CHARS));
+	while (i < n) {
+		indent();
+		fdprintf(2, " list[%d]=%d '%s' %p\n", i, (int)(uintptr_t)list[i],
+				o->data + (int)(uintptr_t)list[i] + string_start,
+				o->data + (int)(uintptr_t)list[i] + string_start);
+		i++;
+	}
+	if (n) {
+		const char *p = o->data + (int)(uintptr_t)list[n - 1] + string_start;
+		indent();
+		fdprintf(2, " total_sz:%ld\n", (long)((p + strlen(p) + 1) - o->data));
+	}
+}
+#else
+# define debug_print_list(prefix, o, n) ((void)0)
+#endif
+
+/* n = o_save_ptr_helper(str, n) "starts new string" by storing an index value
+ * in list[n] so that it points past last stored byte so far.
+ * It returns n+1. */
+static int o_save_ptr_helper(o_string *o, int n)
+{
+	char **list = (char**)o->data;
+	int string_start;
+	int string_len;
+
+	if (!o->has_empty_slot) {
+		string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
+		string_len = o->length - string_start;
+		if (!(n & 0xf)) { /* 0, 0x10, 0x20...? */
+			debug_printf_list("list[%d]=%d string_start=%d (growing)\n", n, string_len, string_start);
+			/* list[n] points to string_start, make space for 16 more pointers */
+			o->maxlen += 0x10 * sizeof(list[0]);
+			o->data = xrealloc(o->data, o->maxlen + 1);
+			list = (char**)o->data;
+			memmove(list + n + 0x10, list + n, string_len);
+			/*
+			 * expand_on_ifs() has a "previous argv[] ends in IFS?"
+			 * check. (grep for -prev-ifs-check-).
+			 * Ensure that argv[-1][last] is not garbage
+			 * but zero bytes, to save index check there.
+			 */
+			list[n + 0x10 - 1] = 0;
+			o->length += 0x10 * sizeof(list[0]);
+		} else {
+			debug_printf_list("list[%d]=%d string_start=%d\n",
+					n, string_len, string_start);
+		}
+	} else {
+		/* We have empty slot at list[n], reuse without growth */
+		string_start = ((n+1 + 0xf) & ~0xf) * sizeof(list[0]); /* NB: n+1! */
+		string_len = o->length - string_start;
+		debug_printf_list("list[%d]=%d string_start=%d (empty slot)\n",
+				n, string_len, string_start);
+		o->has_empty_slot = 0;
+	}
+	o->has_quoted_part = 0;
+	list[n] = (char*)(uintptr_t)string_len;
+	return n + 1;
+}
+
+/* "What was our last o_save_ptr'ed position (byte offset relative o->data)?" */
+static int o_get_last_ptr(o_string *o, int n)
+{
+	char **list = (char**)o->data;
+	int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
+
+	return ((int)(uintptr_t)list[n-1]) + string_start;
+}
+
+/*
+ * Globbing routines.
+ *
+ * Most words in commands need to be globbed, even ones which are
+ * (single or double) quoted. This stems from the possiblity of
+ * constructs like "abc"* and 'abc'* - these should be globbed.
+ * Having a different code path for fully-quoted strings ("abc",
+ * 'abc') would only help performance-wise, but we still need
+ * code for partially-quoted strings.
+ *
+ * Unfortunately, if we want to match bash and ash behavior in all cases,
+ * the logic can't be "shell-syntax argument is first transformed
+ * to a string, then globbed, and if globbing does not match anything,
+ * it is used verbatim". Here are two examples where it fails:
+ *
+ * 	echo 'b\*'?
+ *
+ * The globbing can't be avoided (because of '?' at the end).
+ * The glob pattern is: b\\\*? - IOW, both \ and * are literals
+ * and are glob-escaped. If this does not match, bash/ash print b\*?
+ * - IOW: they "unbackslash" the glob pattern.
+ * Now, look at this:
+ *
+ * 	v='\\\*'; echo b$v?
+ *
+ * The glob pattern is the same here: b\\\*? - the unquoted $v expansion
+ * should be used as glob pattern with no changes. However, if glob
+ * does not match, bash/ash print b\\\*? - NOT THE SAME as first example!
+ *
+ * ash implements this by having an encoded representation of the word
+ * to glob, which IS NOT THE SAME as the glob pattern - it has more data.
+ * Glob pattern is derived from it. If glob fails, the decision what result
+ * should be is made using that encoded representation. Not glob pattern.
+ */
+
+#if ENABLE_HUSH_BRACE_EXPANSION
+/* There in a GNU extension, GLOB_BRACE, but it is not usable:
+ * first, it processes even {a} (no commas), second,
+ * I didn't manage to make it return strings when they don't match
+ * existing files. Need to re-implement it.
+ */
+
+/* Helper */
+static int glob_needed(const char *s)
+{
+	while (*s) {
+		if (*s == '\\') {
+			if (!s[1])
+				return 0;
+			s += 2;
+			continue;
+		}
+		if (*s == '*' || *s == '[' || *s == '?' || *s == '{')
+			return 1;
+		s++;
+	}
+	return 0;
+}
+/* Return pointer to next closing brace or to comma */
+static const char *next_brace_sub(const char *cp)
+{
+	unsigned depth = 0;
+	cp++;
+	while (*cp != '\0') {
+		if (*cp == '\\') {
+			if (*++cp == '\0')
+				break;
+			cp++;
+			continue;
+		}
+		if ((*cp == '}' && depth-- == 0) || (*cp == ',' && depth == 0))
+			break;
+		if (*cp++ == '{')
+			depth++;
+	}
+
+	return *cp != '\0' ? cp : NULL;
+}
+/* Recursive brace globber. Note: may garble pattern[]. */
+static int glob_brace(char *pattern, o_string *o, int n)
+{
+	char *new_pattern_buf;
+	const char *begin;
+	const char *next;
+	const char *rest;
+	const char *p;
+	size_t rest_len;
+
+	debug_printf_glob("glob_brace('%s')\n", pattern);
+
+	begin = pattern;
+	while (1) {
+		if (*begin == '\0')
+			goto simple_glob;
+		if (*begin == '{') {
+			/* Find the first sub-pattern and at the same time
+			 * find the rest after the closing brace */
+			next = next_brace_sub(begin);
+			if (next == NULL) {
+				/* An illegal expression */
+				goto simple_glob;
+			}
+			if (*next == '}') {
+				/* "{abc}" with no commas - illegal
+				 * brace expr, disregard and skip it */
+				begin = next + 1;
+				continue;
+			}
+			break;
+		}
+		if (*begin == '\\' && begin[1] != '\0')
+			begin++;
+		begin++;
+	}
+	debug_printf_glob("begin:%s\n", begin);
+	debug_printf_glob("next:%s\n", next);
+
+	/* Now find the end of the whole brace expression */
+	rest = next;
+	while (*rest != '}') {
+		rest = next_brace_sub(rest);
+		if (rest == NULL) {
+			/* An illegal expression */
+			goto simple_glob;
+		}
+		debug_printf_glob("rest:%s\n", rest);
+	}
+	rest_len = strlen(++rest) + 1;
+
+	/* We are sure the brace expression is well-formed */
+
+	/* Allocate working buffer large enough for our work */
+	new_pattern_buf = xmalloc(strlen(pattern));
+
+	/* We have a brace expression.  BEGIN points to the opening {,
+	 * NEXT points past the terminator of the first element, and REST
+	 * points past the final }.  We will accumulate result names from
+	 * recursive runs for each brace alternative in the buffer using
+	 * GLOB_APPEND.  */
+
+	p = begin + 1;
+	while (1) {
+		/* Construct the new glob expression */
+		memcpy(
+			mempcpy(
+				mempcpy(new_pattern_buf,
+					/* We know the prefix for all sub-patterns */
+					pattern, begin - pattern),
+				p, next - p),
+			rest, rest_len);
+
+		/* Note: glob_brace() may garble new_pattern_buf[].
+		 * That's why we re-copy prefix every time (1st memcpy above).
+		 */
+		n = glob_brace(new_pattern_buf, o, n);
+		if (*next == '}') {
+			/* We saw the last entry */
+			break;
+		}
+		p = next + 1;
+		next = next_brace_sub(next);
+	}
+	free(new_pattern_buf);
+	return n;
+
+ simple_glob:
+	{
+		int gr;
+		glob_t globdata;
+
+		memset(&globdata, 0, sizeof(globdata));
+		gr = glob(pattern, 0, NULL, &globdata);
+		debug_printf_glob("glob('%s'):%d\n", pattern, gr);
+		if (gr != 0) {
+			if (gr == GLOB_NOMATCH) {
+				globfree(&globdata);
+				/* NB: garbles parameter */
+				unbackslash(pattern);
+				o_addstr_with_NUL(o, pattern);
+				debug_printf_glob("glob pattern '%s' is literal\n", pattern);
+				return o_save_ptr_helper(o, n);
+			}
+			if (gr == GLOB_NOSPACE)
+				bb_die_memory_exhausted();
+			/* GLOB_ABORTED? Only happens with GLOB_ERR flag,
+			 * but we didn't specify it. Paranoia again. */
+			bb_error_msg_and_die("glob error %d on '%s'", gr, pattern);
+		}
+		if (globdata.gl_pathv && globdata.gl_pathv[0]) {
+			char **argv = globdata.gl_pathv;
+			while (1) {
+				o_addstr_with_NUL(o, *argv);
+				n = o_save_ptr_helper(o, n);
+				argv++;
+				if (!*argv)
+					break;
+			}
+		}
+		globfree(&globdata);
+	}
+	return n;
+}
+/* Performs globbing on last list[],
+ * saving each result as a new list[].
+ */
+static int perform_glob(o_string *o, int n)
+{
+	char *pattern, *copy;
+
+	debug_printf_glob("start perform_glob: n:%d o->data:%p\n", n, o->data);
+	if (!o->data)
+		return o_save_ptr_helper(o, n);
+	pattern = o->data + o_get_last_ptr(o, n);
+	debug_printf_glob("glob pattern '%s'\n", pattern);
+	if (!glob_needed(pattern)) {
+		/* unbackslash last string in o in place, fix length */
+		o->length = unbackslash(pattern) - o->data;
+		debug_printf_glob("glob pattern '%s' is literal\n", pattern);
+		return o_save_ptr_helper(o, n);
+	}
+
+	copy = xstrdup(pattern);
+	/* "forget" pattern in o */
+	o->length = pattern - o->data;
+	n = glob_brace(copy, o, n);
+	free(copy);
+	if (DEBUG_GLOB)
+		debug_print_list("perform_glob returning", o, n);
+	return n;
+}
+
+#else /* !HUSH_BRACE_EXPANSION */
+
+/* Helper */
+static int glob_needed(const char *s)
+{
+	while (*s) {
+		if (*s == '\\') {
+			if (!s[1])
+				return 0;
+			s += 2;
+			continue;
+		}
+		if (*s == '*' || *s == '[' || *s == '?')
+			return 1;
+		s++;
+	}
+	return 0;
+}
+/* Performs globbing on last list[],
+ * saving each result as a new list[].
+ */
+static int perform_glob(o_string *o, int n)
+{
+	glob_t globdata;
+	int gr;
+	char *pattern;
+
+	debug_printf_glob("start perform_glob: n:%d o->data:%p\n", n, o->data);
+	if (!o->data)
+		return o_save_ptr_helper(o, n);
+	pattern = o->data + o_get_last_ptr(o, n);
+	debug_printf_glob("glob pattern '%s'\n", pattern);
+	if (!glob_needed(pattern)) {
+ literal:
+		/* unbackslash last string in o in place, fix length */
+		o->length = unbackslash(pattern) - o->data;
+		debug_printf_glob("glob pattern '%s' is literal\n", pattern);
+		return o_save_ptr_helper(o, n);
+	}
+
+	memset(&globdata, 0, sizeof(globdata));
+	/* Can't use GLOB_NOCHECK: it does not unescape the string.
+	 * If we glob "*.\*" and don't find anything, we need
+	 * to fall back to using literal "*.*", but GLOB_NOCHECK
+	 * will return "*.\*"!
+	 */
+	gr = glob(pattern, 0, NULL, &globdata);
+	debug_printf_glob("glob('%s'):%d\n", pattern, gr);
+	if (gr != 0) {
+		if (gr == GLOB_NOMATCH) {
+			globfree(&globdata);
+			goto literal;
+		}
+		if (gr == GLOB_NOSPACE)
+			bb_die_memory_exhausted();
+		/* GLOB_ABORTED? Only happens with GLOB_ERR flag,
+		 * but we didn't specify it. Paranoia again. */
+		bb_error_msg_and_die("glob error %d on '%s'", gr, pattern);
+	}
+	if (globdata.gl_pathv && globdata.gl_pathv[0]) {
+		char **argv = globdata.gl_pathv;
+		/* "forget" pattern in o */
+		o->length = pattern - o->data;
+		while (1) {
+			o_addstr_with_NUL(o, *argv);
+			n = o_save_ptr_helper(o, n);
+			argv++;
+			if (!*argv)
+				break;
+		}
+	}
+	globfree(&globdata);
+	if (DEBUG_GLOB)
+		debug_print_list("perform_glob returning", o, n);
+	return n;
+}
+
+#endif /* !HUSH_BRACE_EXPANSION */
+
+/* If o->o_expflags & EXP_FLAG_GLOB, glob the string so far remembered.
+ * Otherwise, just finish current list[] and start new */
+static int o_save_ptr(o_string *o, int n)
+{
+	if (o->o_expflags & EXP_FLAG_GLOB) {
+		/* If o->has_empty_slot, list[n] was already globbed
+		 * (if it was requested back then when it was filled)
+		 * so don't do that again! */
+		if (!o->has_empty_slot)
+			return perform_glob(o, n); /* o_save_ptr_helper is inside */
+	}
+	return o_save_ptr_helper(o, n);
+}
+
+/* "Please convert list[n] to real char* ptrs, and NULL terminate it." */
+static char **o_finalize_list(o_string *o, int n)
+{
+	char **list;
+	int string_start;
+
+	if (DEBUG_EXPAND)
+		debug_print_list("finalized", o, n);
+	debug_printf_expand("finalized n:%d\n", n);
+	list = (char**)o->data;
+	string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
+	list[--n] = NULL;
+	while (n) {
+		n--;
+		list[n] = o->data + (int)(uintptr_t)list[n] + string_start;
+	}
+	return list;
+}
+
+static void free_pipe_list(struct pipe *pi);
+
+/* Returns pi->next - next pipe in the list */
+static struct pipe *free_pipe(struct pipe *pi)
+{
+	struct pipe *next;
+	int i;
+
+	debug_printf_clean("free_pipe (pid %d)\n", getpid());
+	for (i = 0; i < pi->num_cmds; i++) {
+		struct command *command;
+		struct redir_struct *r, *rnext;
+
+		command = &pi->cmds[i];
+		debug_printf_clean("  command %d:\n", i);
+		if (command->argv) {
+			if (DEBUG_CLEAN) {
+				int a;
+				char **p;
+				for (a = 0, p = command->argv; *p; a++, p++) {
+					debug_printf_clean("   argv[%d] = %s\n", a, *p);
+				}
+			}
+			free_strings(command->argv);
+			//command->argv = NULL;
+		}
+		/* not "else if": on syntax error, we may have both! */
+		if (command->group) {
+			debug_printf_clean("   begin group (cmd_type:%d)\n",
+					command->cmd_type);
+			free_pipe_list(command->group);
+			debug_printf_clean("   end group\n");
+			//command->group = NULL;
+		}
+		/* else is crucial here.
+		 * If group != NULL, child_func is meaningless */
+#if ENABLE_HUSH_FUNCTIONS
+		else if (command->child_func) {
+			debug_printf_exec("cmd %p releases child func at %p\n", command, command->child_func);
+			command->child_func->parent_cmd = NULL;
+		}
+#endif
+#if !BB_MMU
+		free(command->group_as_string);
+		//command->group_as_string = NULL;
+#endif
+		for (r = command->redirects; r; r = rnext) {
+			debug_printf_clean("   redirect %d%s",
+					r->rd_fd, redir_table[r->rd_type].descrip);
+			/* guard against the case >$FOO, where foo is unset or blank */
+			if (r->rd_filename) {
+				debug_printf_clean(" fname:'%s'\n", r->rd_filename);
+				free(r->rd_filename);
+				//r->rd_filename = NULL;
+			}
+			debug_printf_clean(" rd_dup:%d\n", r->rd_dup);
+			rnext = r->next;
+			free(r);
+		}
+		//command->redirects = NULL;
+	}
+	free(pi->cmds);   /* children are an array, they get freed all at once */
+	//pi->cmds = NULL;
+#if ENABLE_HUSH_JOB
+	free(pi->cmdtext);
+	//pi->cmdtext = NULL;
+#endif
+
+	next = pi->next;
+	free(pi);
+	return next;
+}
+
+static void free_pipe_list(struct pipe *pi)
+{
+	while (pi) {
+#if HAS_KEYWORDS
+		debug_printf_clean("pipe reserved word %d\n", pi->res_word);
+#endif
+		debug_printf_clean("pipe followup code %d\n", pi->followup);
+		pi = free_pipe(pi);
+	}
+}
+
+
+/*** Parsing routines ***/
+
+#ifndef debug_print_tree
+static void debug_print_tree(struct pipe *pi, int lvl)
+{
+	static const char *const PIPE[] = {
+		[PIPE_SEQ] = "SEQ",
+		[PIPE_AND] = "AND",
+		[PIPE_OR ] = "OR" ,
+		[PIPE_BG ] = "BG" ,
+	};
+	static const char *RES[] = {
+		[RES_NONE ] = "NONE" ,
+# if ENABLE_HUSH_IF
+		[RES_IF   ] = "IF"   ,
+		[RES_THEN ] = "THEN" ,
+		[RES_ELIF ] = "ELIF" ,
+		[RES_ELSE ] = "ELSE" ,
+		[RES_FI   ] = "FI"   ,
+# endif
+# if ENABLE_HUSH_LOOPS
+		[RES_FOR  ] = "FOR"  ,
+		[RES_WHILE] = "WHILE",
+		[RES_UNTIL] = "UNTIL",
+		[RES_DO   ] = "DO"   ,
+		[RES_DONE ] = "DONE" ,
+# endif
+# if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
+		[RES_IN   ] = "IN"   ,
+# endif
+# if ENABLE_HUSH_CASE
+		[RES_CASE ] = "CASE" ,
+		[RES_CASE_IN ] = "CASE_IN" ,
+		[RES_MATCH] = "MATCH",
+		[RES_CASE_BODY] = "CASE_BODY",
+		[RES_ESAC ] = "ESAC" ,
+# endif
+		[RES_XXXX ] = "XXXX" ,
+		[RES_SNTX ] = "SNTX" ,
+	};
+	static const char *const CMDTYPE[] = {
+		"{}",
+		"()",
+		"[noglob]",
+# if ENABLE_HUSH_FUNCTIONS
+		"func()",
+# endif
+	};
+
+	int pin, prn;
+
+	pin = 0;
+	while (pi) {
+		fdprintf(2, "%*spipe %d #cmds:%d %sres_word=%s followup=%d %s\n",
+				lvl*2, "",
+				pin,
+				pi->num_cmds,
+				(IF_HAS_KEYWORDS(pi->pi_inverted ? "! " :) ""),
+				RES[pi->res_word],
+				pi->followup, PIPE[pi->followup]
+		);
+		prn = 0;
+		while (prn < pi->num_cmds) {
+			struct command *command = &pi->cmds[prn];
+			char **argv = command->argv;
+
+			fdprintf(2, "%*s cmd %d assignment_cnt:%d",
+					lvl*2, "", prn,
+					command->assignment_cnt);
+# if ENABLE_HUSH_LINENO_VAR
+			fdprintf(2, " LINENO:%u", command->lineno);
+# endif
+			if (command->group) {
+				fdprintf(2, " group %s: (argv=%p)%s%s\n",
+						CMDTYPE[command->cmd_type],
+						argv
+# if !BB_MMU
+						, " group_as_string:", command->group_as_string
+# else
+						, "", ""
+# endif
+				);
+				debug_print_tree(command->group, lvl+1);
+				prn++;
+				continue;
+			}
+			if (argv) while (*argv) {
+				fdprintf(2, " '%s'", *argv);
+				argv++;
+			}
+			if (command->redirects)
+				fdprintf(2, " {redir}");
+			fdprintf(2, "\n");
+			prn++;
+		}
+		pi = pi->next;
+		pin++;
+	}
+}
+#endif /* debug_print_tree */
+
+static struct pipe *new_pipe(void)
+{
+	struct pipe *pi;
+	pi = xzalloc(sizeof(struct pipe));
+	/*pi->res_word = RES_NONE; - RES_NONE is 0 anyway */
+	return pi;
+}
+
+/* Command (member of a pipe) is complete, or we start a new pipe
+ * if ctx->command is NULL.
+ * No errors possible here.
+ */
+static int done_command(struct parse_context *ctx)
+{
+	/* The command is really already in the pipe structure, so
+	 * advance the pipe counter and make a new, null command. */
+	struct pipe *pi = ctx->pipe;
+	struct command *command = ctx->command;
+
+#if 0	/* Instead we emit error message at run time */
+	if (ctx->pending_redirect) {
+		/* For example, "cmd >" (no filename to redirect to) */
+		syntax_error("invalid redirect");
+		ctx->pending_redirect = NULL;
+	}
+#endif
+
+	if (command) {
+		if (IS_NULL_CMD(command)) {
+			debug_printf_parse("done_command: skipping null cmd, num_cmds=%d\n", pi->num_cmds);
+			goto clear_and_ret;
+		}
+		pi->num_cmds++;
+		debug_printf_parse("done_command: ++num_cmds=%d\n", pi->num_cmds);
+		//debug_print_tree(ctx->list_head, 20);
+	} else {
+		debug_printf_parse("done_command: initializing, num_cmds=%d\n", pi->num_cmds);
+	}
+
+	/* Only real trickiness here is that the uncommitted
+	 * command structure is not counted in pi->num_cmds. */
+	pi->cmds = xrealloc(pi->cmds, sizeof(*pi->cmds) * (pi->num_cmds+1));
+	ctx->command = command = &pi->cmds[pi->num_cmds];
+ clear_and_ret:
+	memset(command, 0, sizeof(*command));
+#if ENABLE_HUSH_LINENO_VAR
+	command->lineno = G.parse_lineno;
+	debug_printf_parse("command->lineno = G.parse_lineno (%u)\n", G.parse_lineno);
+#endif
+	return pi->num_cmds; /* used only for 0/nonzero check */
+}
+
+static void done_pipe(struct parse_context *ctx, pipe_style type)
+{
+	int not_null;
+
+	debug_printf_parse("done_pipe entered, followup %d\n", type);
+	/* Close previous command */
+	not_null = done_command(ctx);
+#if HAS_KEYWORDS
+	ctx->pipe->pi_inverted = ctx->ctx_inverted;
+	ctx->ctx_inverted = 0;
+	ctx->pipe->res_word = ctx->ctx_res_w;
+#endif
+	if (type == PIPE_BG && ctx->list_head != ctx->pipe) {
+		/* Necessary since && and || have precedence over &:
+		 * "cmd1 && cmd2 &" must spawn both cmds, not only cmd2,
+		 * in a backgrounded subshell.
+		 */
+		struct pipe *pi;
+		struct command *command;
+
+		/* Is this actually this construct, all pipes end with && or ||? */
+		pi = ctx->list_head;
+		while (pi != ctx->pipe) {
+			if (pi->followup != PIPE_AND && pi->followup != PIPE_OR)
+				goto no_conv;
+			pi = pi->next;
+		}
+
+		debug_printf_parse("BG with more than one pipe, converting to { p1 &&...pN; } &\n");
+		pi->followup = PIPE_SEQ; /* close pN _not_ with "&"! */
+		pi = xzalloc(sizeof(*pi));
+		pi->followup = PIPE_BG;
+		pi->num_cmds = 1;
+		pi->cmds = xzalloc(sizeof(pi->cmds[0]));
+		command = &pi->cmds[0];
+		if (CMD_NORMAL != 0) /* "if xzalloc didn't do that already" */
+			command->cmd_type = CMD_NORMAL;
+		command->group = ctx->list_head;
+#if !BB_MMU
+		command->group_as_string = xstrndup(
+			    ctx->as_string.data,
+			    ctx->as_string.length - 1 /* do not copy last char, "&" */
+		);
+#endif
+		/* Replace all pipes in ctx with one newly created */
+		ctx->list_head = ctx->pipe = pi;
+		/* for cases like "cmd && &", do not be tricked by last command
+		 * being null - the entire {...} & is NOT null! */
+		not_null = 1;
+	} else {
+ no_conv:
+		ctx->pipe->followup = type;
+	}
+
+	/* Without this check, even just <enter> on command line generates
+	 * tree of three NOPs (!). Which is harmless but annoying.
+	 * IOW: it is safe to do it unconditionally. */
+	if (not_null
+#if ENABLE_HUSH_IF
+	 || ctx->ctx_res_w == RES_FI
+#endif
+#if ENABLE_HUSH_LOOPS
+	 || ctx->ctx_res_w == RES_DONE
+	 || ctx->ctx_res_w == RES_FOR
+	 || ctx->ctx_res_w == RES_IN
+#endif
+#if ENABLE_HUSH_CASE
+	 || ctx->ctx_res_w == RES_ESAC
+#endif
+	) {
+		struct pipe *new_p;
+		debug_printf_parse("done_pipe: adding new pipe: "
+				"not_null:%d ctx->ctx_res_w:%d\n",
+				not_null, ctx->ctx_res_w);
+		new_p = new_pipe();
+		ctx->pipe->next = new_p;
+		ctx->pipe = new_p;
+		/* RES_THEN, RES_DO etc are "sticky" -
+		 * they remain set for pipes inside if/while.
+		 * This is used to control execution.
+		 * RES_FOR and RES_IN are NOT sticky (needed to support
+		 * cases where variable or value happens to match a keyword):
+		 */
+#if ENABLE_HUSH_LOOPS
+		if (ctx->ctx_res_w == RES_FOR
+		 || ctx->ctx_res_w == RES_IN)
+			ctx->ctx_res_w = RES_NONE;
+#endif
+#if ENABLE_HUSH_CASE
+		if (ctx->ctx_res_w == RES_MATCH)
+			ctx->ctx_res_w = RES_CASE_BODY;
+		if (ctx->ctx_res_w == RES_CASE)
+			ctx->ctx_res_w = RES_CASE_IN;
+#endif
+		ctx->command = NULL; /* trick done_command below */
+		/* Create the memory for command, roughly:
+		 * ctx->pipe->cmds = new struct command;
+		 * ctx->command = &ctx->pipe->cmds[0];
+		 */
+		done_command(ctx);
+		//debug_print_tree(ctx->list_head, 10);
+	}
+	debug_printf_parse("done_pipe return\n");
+}
+
+static void initialize_context(struct parse_context *ctx)
+{
+	memset(ctx, 0, sizeof(*ctx));
+	if (MAYBE_ASSIGNMENT != 0)
+		ctx->is_assignment = MAYBE_ASSIGNMENT;
+	ctx->pipe = ctx->list_head = new_pipe();
+	/* Create the memory for command, roughly:
+	 * ctx->pipe->cmds = new struct command;
+	 * ctx->command = &ctx->pipe->cmds[0];
+	 */
+	done_command(ctx);
+}
+
+/* If a reserved word is found and processed, parse context is modified
+ * and 1 is returned.
+ */
+#if HAS_KEYWORDS
+struct reserved_combo {
+	char literal[6];
+	unsigned char res;
+	unsigned char assignment_flag;
+	uint32_t flag;
+};
+enum {
+	FLAG_END   = (1 << RES_NONE ),
+# if ENABLE_HUSH_IF
+	FLAG_IF    = (1 << RES_IF   ),
+	FLAG_THEN  = (1 << RES_THEN ),
+	FLAG_ELIF  = (1 << RES_ELIF ),
+	FLAG_ELSE  = (1 << RES_ELSE ),
+	FLAG_FI    = (1 << RES_FI   ),
+# endif
+# if ENABLE_HUSH_LOOPS
+	FLAG_FOR   = (1 << RES_FOR  ),
+	FLAG_WHILE = (1 << RES_WHILE),
+	FLAG_UNTIL = (1 << RES_UNTIL),
+	FLAG_DO    = (1 << RES_DO   ),
+	FLAG_DONE  = (1 << RES_DONE ),
+	FLAG_IN    = (1 << RES_IN   ),
+# endif
+# if ENABLE_HUSH_CASE
+	FLAG_MATCH = (1 << RES_MATCH),
+	FLAG_ESAC  = (1 << RES_ESAC ),
+# endif
+	FLAG_START = (1 << RES_XXXX ),
+};
+
+static const struct reserved_combo* match_reserved_word(o_string *word)
+{
+	/* Mostly a list of accepted follow-up reserved words.
+	 * FLAG_END means we are done with the sequence, and are ready
+	 * to turn the compound list into a command.
+	 * FLAG_START means the word must start a new compound list.
+	 */
+	static const struct reserved_combo reserved_list[] ALIGN4 = {
+# if ENABLE_HUSH_IF
+		{ "!",     RES_NONE,  NOT_ASSIGNMENT  , 0 },
+		{ "if",    RES_IF,    MAYBE_ASSIGNMENT, FLAG_THEN | FLAG_START },
+		{ "then",  RES_THEN,  MAYBE_ASSIGNMENT, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
+		{ "elif",  RES_ELIF,  MAYBE_ASSIGNMENT, FLAG_THEN },
+		{ "else",  RES_ELSE,  MAYBE_ASSIGNMENT, FLAG_FI   },
+		{ "fi",    RES_FI,    NOT_ASSIGNMENT  , FLAG_END  },
+# endif
+# if ENABLE_HUSH_LOOPS
+		{ "for",   RES_FOR,   NOT_ASSIGNMENT  , FLAG_IN | FLAG_DO | FLAG_START },
+		{ "while", RES_WHILE, MAYBE_ASSIGNMENT, FLAG_DO | FLAG_START },
+		{ "until", RES_UNTIL, MAYBE_ASSIGNMENT, FLAG_DO | FLAG_START },
+		{ "in",    RES_IN,    NOT_ASSIGNMENT  , FLAG_DO   },
+		{ "do",    RES_DO,    MAYBE_ASSIGNMENT, FLAG_DONE },
+		{ "done",  RES_DONE,  NOT_ASSIGNMENT  , FLAG_END  },
+# endif
+# if ENABLE_HUSH_CASE
+		{ "case",  RES_CASE,  NOT_ASSIGNMENT  , FLAG_MATCH | FLAG_START },
+		{ "esac",  RES_ESAC,  NOT_ASSIGNMENT  , FLAG_END  },
+# endif
+	};
+	const struct reserved_combo *r;
+
+	for (r = reserved_list; r < reserved_list + ARRAY_SIZE(reserved_list); r++) {
+		if (strcmp(word->data, r->literal) == 0)
+			return r;
+	}
+	return NULL;
+}
+/* Return NULL: not a keyword, else: keyword
+ */
+static const struct reserved_combo* reserved_word(struct parse_context *ctx)
+{
+# if ENABLE_HUSH_CASE
+	static const struct reserved_combo reserved_match = {
+		"",        RES_MATCH, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_ESAC
+	};
+# endif
+	const struct reserved_combo *r;
+
+	if (ctx->word.has_quoted_part)
+		return 0;
+	r = match_reserved_word(&ctx->word);
+	if (!r)
+		return r; /* NULL */
+
+	debug_printf("found reserved word %s, res %d\n", r->literal, r->res);
+# if ENABLE_HUSH_CASE
+	if (r->res == RES_IN && ctx->ctx_res_w == RES_CASE_IN) {
+		/* "case word IN ..." - IN part starts first MATCH part */
+		r = &reserved_match;
+	} else
+# endif
+	if (r->flag == 0) { /* '!' */
+		if (ctx->ctx_inverted) { /* bash doesn't accept '! ! true' */
+			syntax_error("! ! command");
+			ctx->ctx_res_w = RES_SNTX;
+		}
+		ctx->ctx_inverted = 1;
+		return r;
+	}
+	if (r->flag & FLAG_START) {
+		struct parse_context *old;
+
+		old = xmemdup(ctx, sizeof(*ctx));
+		debug_printf_parse("push stack %p\n", old);
+		initialize_context(ctx);
+		ctx->stack = old;
+	} else if (/*ctx->ctx_res_w == RES_NONE ||*/ !(ctx->old_flag & (1 << r->res))) {
+		syntax_error_at(ctx->word.data);
+		ctx->ctx_res_w = RES_SNTX;
+		return r;
+	} else {
+		/* "{...} fi" is ok. "{...} if" is not
+		 * Example:
+		 * if { echo foo; } then { echo bar; } fi */
+		if (ctx->command->group)
+			done_pipe(ctx, PIPE_SEQ);
+	}
+
+	ctx->ctx_res_w = r->res;
+	ctx->old_flag = r->flag;
+	ctx->is_assignment = r->assignment_flag;
+	debug_printf_parse("ctx->is_assignment='%s'\n", assignment_flag[ctx->is_assignment]);
+
+	if (ctx->old_flag & FLAG_END) {
+		struct parse_context *old;
+
+		done_pipe(ctx, PIPE_SEQ);
+		debug_printf_parse("pop stack %p\n", ctx->stack);
+		old = ctx->stack;
+		old->command->group = ctx->list_head;
+		old->command->cmd_type = CMD_NORMAL;
+# if !BB_MMU
+		/* At this point, the compound command's string is in
+		 * ctx->as_string... except for the leading keyword!
+		 * Consider this example: "echo a | if true; then echo a; fi"
+		 * ctx->as_string will contain "true; then echo a; fi",
+		 * with "if " remaining in old->as_string!
+		 */
+		{
+			char *str;
+			int len = old->as_string.length;
+			/* Concatenate halves */
+			o_addstr(&old->as_string, ctx->as_string.data);
+			o_free(&ctx->as_string);
+			/* Find where leading keyword starts in first half */
+			str = old->as_string.data + len;
+			if (str > old->as_string.data)
+				str--; /* skip whitespace after keyword */
+			while (str > old->as_string.data && isalpha(str[-1]))
+				str--;
+			/* Ugh, we're done with this horrid hack */
+			old->command->group_as_string = xstrdup(str);
+			debug_printf_parse("pop, remembering as:'%s'\n",
+					old->command->group_as_string);
+		}
+# endif
+		*ctx = *old;   /* physical copy */
+		free(old);
+	}
+	return r;
+}
+#endif /* HAS_KEYWORDS */
+
+/* Word is complete, look at it and update parsing context.
+ * Normal return is 0. Syntax errors return 1.
+ * Note: on return, word is reset, but not o_free'd!
+ */
+static int done_word(struct parse_context *ctx)
+{
+	struct command *command = ctx->command;
+
+	debug_printf_parse("done_word entered: '%s' %p\n", ctx->word.data, command);
+	if (ctx->word.length == 0 && !ctx->word.has_quoted_part) {
+		debug_printf_parse("done_word return 0: true null, ignored\n");
+		return 0;
+	}
+
+	if (ctx->pending_redirect) {
+		/* We do not glob in e.g. >*.tmp case. bash seems to glob here
+		 * only if run as "bash", not "sh" */
+		/* http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html
+		 * "2.7 Redirection
+		 * If the redirection operator is "<<" or "<<-", the word
+		 * that follows the redirection operator shall be
+		 * subjected to quote removal; it is unspecified whether
+		 * any of the other expansions occur. For the other
+		 * redirection operators, the word that follows the
+		 * redirection operator shall be subjected to tilde
+		 * expansion, parameter expansion, command substitution,
+		 * arithmetic expansion, and quote removal.
+		 * Pathname expansion shall not be performed
+		 * on the word by a non-interactive shell; an interactive
+		 * shell may perform it, but shall do so only when
+		 * the expansion would result in one word."
+		 */
+//bash does not do parameter/command substitution or arithmetic expansion
+//for _heredoc_ redirection word: these constructs look for exact eof marker
+// as written:
+// <<EOF$t
+// <<EOF$((1))
+// <<EOF`true`  [this case also makes heredoc "quoted", a-la <<"EOF". Probably bash-4.3.43 bug]
+
+		ctx->pending_redirect->rd_filename = xstrdup(ctx->word.data);
+		/* Cater for >\file case:
+		 * >\a creates file a; >\\a, >"\a", >"\\a" create file \a
+		 * Same with heredocs:
+		 * for <<\H delim is H; <<\\H, <<"\H", <<"\\H" - \H
+		 */
+		if (ctx->pending_redirect->rd_type == REDIRECT_HEREDOC) {
+			unbackslash(ctx->pending_redirect->rd_filename);
+			/* Is it <<"HEREDOC"? */
+			if (ctx->word.has_quoted_part) {
+				ctx->pending_redirect->rd_dup |= HEREDOC_QUOTED;
+			}
+		}
+		debug_printf_parse("word stored in rd_filename: '%s'\n", ctx->word.data);
+		ctx->pending_redirect = NULL;
+	} else {
+#if HAS_KEYWORDS
+# if ENABLE_HUSH_CASE
+		if (ctx->ctx_dsemicolon
+		 && strcmp(ctx->word.data, "esac") != 0 /* not "... pattern) cmd;; esac" */
+		) {
+			/* already done when ctx_dsemicolon was set to 1: */
+			/* ctx->ctx_res_w = RES_MATCH; */
+			ctx->ctx_dsemicolon = 0;
+		} else
+# endif
+# if defined(CMD_TEST2_SINGLEWORD_NOGLOB)
+		if (command->cmd_type == CMD_TEST2_SINGLEWORD_NOGLOB
+		 && strcmp(ctx->word.data, "]]") == 0
+		) {
+			/* allow "[[ ]] >file" etc */
+			command->cmd_type = CMD_SINGLEWORD_NOGLOB;
+		} else
+# endif
+		if (!command->argv /* if it's the first word... */
+# if ENABLE_HUSH_LOOPS
+		 && ctx->ctx_res_w != RES_FOR /* ...not after FOR or IN */
+		 && ctx->ctx_res_w != RES_IN
+# endif
+# if ENABLE_HUSH_CASE
+		 && ctx->ctx_res_w != RES_CASE
+# endif
+		) {
+			const struct reserved_combo *reserved;
+			reserved = reserved_word(ctx);
+			debug_printf_parse("checking for reserved-ness: %d\n", !!reserved);
+			if (reserved) {
+# if ENABLE_HUSH_LINENO_VAR
+/* Case:
+ * "while ...; do
+ *	cmd ..."
+ * If we don't close the pipe _now_, immediately after "do", lineno logic
+ * sees "cmd" as starting at "do" - i.e., at the previous line.
+ */
+				if (0
+				 IF_HUSH_IF(|| reserved->res == RES_THEN)
+				 IF_HUSH_IF(|| reserved->res == RES_ELIF)
+				 IF_HUSH_IF(|| reserved->res == RES_ELSE)
+				 IF_HUSH_LOOPS(|| reserved->res == RES_DO)
+				) {
+					done_pipe(ctx, PIPE_SEQ);
+				}
+# endif
+				o_reset_to_empty_unquoted(&ctx->word);
+				debug_printf_parse("done_word return %d\n",
+						(ctx->ctx_res_w == RES_SNTX));
+				return (ctx->ctx_res_w == RES_SNTX);
+			}
+# if defined(CMD_TEST2_SINGLEWORD_NOGLOB)
+			if (strcmp(ctx->word.data, "[[") == 0) {
+				command->cmd_type = CMD_TEST2_SINGLEWORD_NOGLOB;
+			} else
+# endif
+# if defined(CMD_SINGLEWORD_NOGLOB)
+			if (0
+			/* In bash, local/export/readonly are special, args
+			 * are assignments and therefore expansion of them
+			 * should be "one-word" expansion:
+			 *  $ export i=`echo 'a  b'` # one arg: "i=a  b"
+			 * compare with:
+			 *  $ ls i=`echo 'a  b'`     # two args: "i=a" and "b"
+			 *  ls: cannot access i=a: No such file or directory
+			 *  ls: cannot access b: No such file or directory
+			 * Note: bash 3.2.33(1) does this only if export word
+			 * itself is not quoted:
+			 *  $ export i=`echo 'aaa  bbb'`; echo "$i"
+			 *  aaa  bbb
+			 *  $ "export" i=`echo 'aaa  bbb'`; echo "$i"
+			 *  aaa
+			 */
+			 IF_HUSH_LOCAL(   || strcmp(ctx->word.data, "local") == 0)
+			 IF_HUSH_EXPORT(  || strcmp(ctx->word.data, "export") == 0)
+			 IF_HUSH_READONLY(|| strcmp(ctx->word.data, "readonly") == 0)
+			) {
+				command->cmd_type = CMD_SINGLEWORD_NOGLOB;
+			}
+# else
+			{ /* empty block to pair "if ... else" */ }
+# endif
+		}
+#endif /* HAS_KEYWORDS */
+
+		if (command->group) {
+			/* "{ echo foo; } echo bar" - bad */
+			syntax_error_at(ctx->word.data);
+			debug_printf_parse("done_word return 1: syntax error, "
+					"groups and arglists don't mix\n");
+			return 1;
+		}
+
+		/* If this word wasn't an assignment, next ones definitely
+		 * can't be assignments. Even if they look like ones. */
+		if (ctx->is_assignment != DEFINITELY_ASSIGNMENT
+		 && ctx->is_assignment != WORD_IS_KEYWORD
+		) {
+			ctx->is_assignment = NOT_ASSIGNMENT;
+		} else {
+			if (ctx->is_assignment == DEFINITELY_ASSIGNMENT) {
+				command->assignment_cnt++;
+				debug_printf_parse("++assignment_cnt=%d\n", command->assignment_cnt);
+			}
+			debug_printf_parse("ctx->is_assignment was:'%s'\n", assignment_flag[ctx->is_assignment]);
+			ctx->is_assignment = MAYBE_ASSIGNMENT;
+		}
+		debug_printf_parse("ctx->is_assignment='%s'\n", assignment_flag[ctx->is_assignment]);
+		command->argv = add_string_to_strings(command->argv, xstrdup(ctx->word.data));
+		debug_print_strings("word appended to argv", command->argv);
+	}
+
+#if ENABLE_HUSH_LOOPS
+	if (ctx->ctx_res_w == RES_FOR) {
+		if (ctx->word.has_quoted_part
+		 || endofname(command->argv[0])[0] != '\0'
+		) {
+			/* bash says just "not a valid identifier" */
+			syntax_error("bad variable name in for");
+			return 1;
+		}
+		/* Force FOR to have just one word (variable name) */
+		/* NB: basically, this makes hush see "for v in ..."
+		 * syntax as if it is "for v; in ...". FOR and IN become
+		 * two pipe structs in parse tree. */
+		done_pipe(ctx, PIPE_SEQ);
+	}
+#endif
+#if ENABLE_HUSH_CASE
+	/* Force CASE to have just one word */
+	if (ctx->ctx_res_w == RES_CASE) {
+		done_pipe(ctx, PIPE_SEQ);
+	}
+#endif
+
+	o_reset_to_empty_unquoted(&ctx->word);
+
+	debug_printf_parse("done_word return 0\n");
+	return 0;
+}
+
+
+/* Peek ahead in the input to find out if we have a "&n" construct,
+ * as in "2>&1", that represents duplicating a file descriptor.
+ * Return:
+ * REDIRFD_CLOSE if >&- "close fd" construct is seen,
+ * REDIRFD_SYNTAX_ERR if syntax error,
+ * REDIRFD_TO_FILE if no & was seen,
+ * or the number found.
+ */
+#if BB_MMU
+#define parse_redir_right_fd(as_string, input) \
+	parse_redir_right_fd(input)
+#endif
+static int parse_redir_right_fd(o_string *as_string, struct in_str *input)
+{
+	int ch, d, ok;
+
+	ch = i_peek(input);
+	if (ch != '&')
+		return REDIRFD_TO_FILE;
+
+	ch = i_getch(input);  /* get the & */
+	nommu_addchr(as_string, ch);
+	ch = i_peek(input);
+	if (ch == '-') {
+		ch = i_getch(input);
+		nommu_addchr(as_string, ch);
+		return REDIRFD_CLOSE;
+	}
+	d = 0;
+	ok = 0;
+	while (ch != EOF && isdigit(ch)) {
+		d = d*10 + (ch-'0');
+		ok = 1;
+		ch = i_getch(input);
+		nommu_addchr(as_string, ch);
+		ch = i_peek(input);
+	}
+	if (ok) return d;
+
+//TODO: this is the place to catch ">&file" bashism (redirect both fd 1 and 2)
+
+	bb_simple_error_msg("ambiguous redirect");
+	return REDIRFD_SYNTAX_ERR;
+}
+
+/* Return code is 0 normal, 1 if a syntax error is detected
+ */
+static int parse_redirect(struct parse_context *ctx,
+		int fd,
+		redir_type style,
+		struct in_str *input)
+{
+	struct command *command = ctx->command;
+	struct redir_struct *redir;
+	struct redir_struct **redirp;
+	int dup_num;
+
+	dup_num = REDIRFD_TO_FILE;
+	if (style != REDIRECT_HEREDOC) {
+		/* Check for a '>&1' type redirect */
+		dup_num = parse_redir_right_fd(&ctx->as_string, input);
+		if (dup_num == REDIRFD_SYNTAX_ERR)
+			return 1;
+	} else {
+		int ch = i_peek_and_eat_bkslash_nl(input);
+		dup_num = (ch == '-'); /* HEREDOC_SKIPTABS bit is 1 */
+		if (dup_num) { /* <<-... */
+			ch = i_getch(input);
+			nommu_addchr(&ctx->as_string, ch);
+			ch = i_peek(input);
+		}
+	}
+
+	if (style == REDIRECT_OVERWRITE && dup_num == REDIRFD_TO_FILE) {
+		int ch = i_peek_and_eat_bkslash_nl(input);
+		if (ch == '|') {
+			/* >|FILE redirect ("clobbering" >).
+			 * Since we do not support "set -o noclobber" yet,
+			 * >| and > are the same for now. Just eat |.
+			 */
+			ch = i_getch(input);
+			nommu_addchr(&ctx->as_string, ch);
+		}
+	}
+
+	/* Create a new redir_struct and append it to the linked list */
+	redirp = &command->redirects;
+	while ((redir = *redirp) != NULL) {
+		redirp = &(redir->next);
+	}
+	*redirp = redir = xzalloc(sizeof(*redir));
+	/* redir->next = NULL; */
+	/* redir->rd_filename = NULL; */
+	redir->rd_type = style;
+	redir->rd_fd = (fd == -1) ? redir_table[style].default_fd : fd;
+
+	debug_printf_parse("redirect type %d %s\n", redir->rd_fd,
+				redir_table[style].descrip);
+
+	redir->rd_dup = dup_num;
+	if (style != REDIRECT_HEREDOC && dup_num != REDIRFD_TO_FILE) {
+		/* Erik had a check here that the file descriptor in question
+		 * is legit; I postpone that to "run time"
+		 * A "-" representation of "close me" shows up as a -3 here */
+		debug_printf_parse("duplicating redirect '%d>&%d'\n",
+				redir->rd_fd, redir->rd_dup);
+	} else {
+#if 0		/* Instead we emit error message at run time */
+		if (ctx->pending_redirect) {
+			/* For example, "cmd > <file" */
+			syntax_error("invalid redirect");
+		}
+#endif
+		/* Set ctx->pending_redirect, so we know what to do at the
+		 * end of the next parsed word. */
+		ctx->pending_redirect = redir;
+	}
+	return 0;
+}
+
+/* If a redirect is immediately preceded by a number, that number is
+ * supposed to tell which file descriptor to redirect.  This routine
+ * looks for such preceding numbers.  In an ideal world this routine
+ * needs to handle all the following classes of redirects...
+ *     echo 2>foo     # redirects fd  2 to file "foo", nothing passed to echo
+ *     echo 49>foo    # redirects fd 49 to file "foo", nothing passed to echo
+ *     echo -2>foo    # redirects fd  1 to file "foo",    "-2" passed to echo
+ *     echo 49x>foo   # redirects fd  1 to file "foo",   "49x" passed to echo
+ *
+ * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html
+ * "2.7 Redirection
+ * ... If n is quoted, the number shall not be recognized as part of
+ * the redirection expression. For example:
+ * echo \2>a
+ * writes the character 2 into file a"
+ * We are getting it right by setting ->has_quoted_part on any \<char>
+ *
+ * A -1 return means no valid number was found,
+ * the caller should use the appropriate default for this redirection.
+ */
+static int redirect_opt_num(o_string *o)
+{
+	int num;
+
+	if (o->data == NULL)
+		return -1;
+	num = bb_strtou(o->data, NULL, 10);
+	if (errno || num < 0)
+		return -1;
+	o_reset_to_empty_unquoted(o);
+	return num;
+}
+
+#if BB_MMU
+#define fetch_till_str(as_string, input, word, skip_tabs) \
+	fetch_till_str(input, word, skip_tabs)
+#endif
+static char *fetch_till_str(o_string *as_string,
+		struct in_str *input,
+		const char *word,
+		int heredoc_flags)
+{
+	o_string heredoc = NULL_O_STRING;
+	unsigned past_EOL;
+	int prev = 0; /* not \ */
+	int ch;
+
+	/* Starting with "" is necessary for this case:
+	 * cat <<EOF
+	 *
+	 * xxx
+	 * EOF
+	 */
+	heredoc.data = xzalloc(1); /* start as "", not as NULL */
+
+	goto jump_in;
+
+	while (1) {
+		ch = i_getch(input);
+		if (ch != EOF)
+			nommu_addchr(as_string, ch);
+		if (ch == '\n' || ch == EOF) {
+ check_heredoc_end:
+			if ((heredoc_flags & HEREDOC_QUOTED) || prev != '\\') {
+				/* End-of-line, and not a line continuation */
+				if (strcmp(heredoc.data + past_EOL, word) == 0) {
+					heredoc.data[past_EOL] = '\0';
+					debug_printf_heredoc("parsed '%s' heredoc '%s'\n", word, heredoc.data);
+					return heredoc.data;
+				}
+				if (ch == '\n') {
+					/* This is a new line.
+					 * Remember position and backslash-escaping status.
+					 */
+					o_addchr(&heredoc, ch);
+					prev = ch;
+ jump_in:
+					past_EOL = heredoc.length;
+					/* Get 1st char of next line, possibly skipping leading tabs */
+					do {
+						ch = i_getch(input);
+						if (ch != EOF)
+							nommu_addchr(as_string, ch);
+					} while ((heredoc_flags & HEREDOC_SKIPTABS) && ch == '\t');
+					/* If this immediately ended the line,
+					 * go back to end-of-line checks.
+					 */
+					if (ch == '\n')
+						goto check_heredoc_end;
+				}
+			} else {
+				/* Backslash-line continuation in an unquoted
+				 * heredoc. This does not need special handling
+				 * for heredoc body (unquoted heredocs are
+				 * expanded on "execution" and that would take
+				 * care of this case too), but not the case
+				 * of line continuation *in terminator*:
+				 *  cat <<EOF
+				 *  Ok1
+				 *  EO\
+				 *  F
+				 */
+				heredoc.data[--heredoc.length] = '\0';
+				prev = 0; /* not '\' */
+				continue;
+			}
+		}
+		if (ch == EOF) {
+			o_free(&heredoc);
+			return NULL; /* error */
+		}
+		o_addchr(&heredoc, ch);
+		nommu_addchr(as_string, ch);
+		if (prev == '\\' && ch == '\\')
+			/* Correctly handle foo\\<eol> (not a line cont.) */
+			prev = 0; /* not '\' */
+		else
+			prev = ch;
+	}
+}
+
+/* Look at entire parse tree for not-yet-loaded REDIRECT_HEREDOCs
+ * and load them all. There should be exactly heredoc_cnt of them.
+ */
+#if BB_MMU
+#define fetch_heredocs(as_string, pi, heredoc_cnt, input) \
+	fetch_heredocs(pi, heredoc_cnt, input)
+#endif
+static int fetch_heredocs(o_string *as_string, struct pipe *pi, int heredoc_cnt, struct in_str *input)
+{
+	while (pi && heredoc_cnt) {
+		int i;
+		struct command *cmd = pi->cmds;
+
+		debug_printf_heredoc("fetch_heredocs: num_cmds:%d cmd argv0:'%s'\n",
+				pi->num_cmds,
+				cmd->argv ? cmd->argv[0] : "NONE"
+		);
+		for (i = 0; i < pi->num_cmds; i++) {
+			struct redir_struct *redir = cmd->redirects;
+
+			debug_printf_heredoc("fetch_heredocs: %d cmd argv0:'%s'\n",
+					i, cmd->argv ? cmd->argv[0] : "NONE");
+			while (redir) {
+				if (redir->rd_type == REDIRECT_HEREDOC) {
+					char *p;
+
+					redir->rd_type = REDIRECT_HEREDOC2;
+					/* redir->rd_dup is (ab)used to indicate <<- */
+					p = fetch_till_str(as_string, input,
+							redir->rd_filename, redir->rd_dup);
+					if (!p) {
+						syntax_error("unexpected EOF in here document");
+						return -1;
+					}
+					free(redir->rd_filename);
+					redir->rd_filename = p;
+					heredoc_cnt--;
+				}
+				redir = redir->next;
+			}
+			if (cmd->group) {
+				//bb_error_msg("%s:%u heredoc_cnt:%d", __func__, __LINE__, heredoc_cnt);
+				heredoc_cnt = fetch_heredocs(as_string, cmd->group, heredoc_cnt, input);
+				//bb_error_msg("%s:%u heredoc_cnt:%d", __func__, __LINE__, heredoc_cnt);
+				if (heredoc_cnt < 0)
+					return heredoc_cnt; /* error */
+			}
+			cmd++;
+		}
+		pi = pi->next;
+	}
+	return heredoc_cnt;
+}
+
+
+static int run_list(struct pipe *pi);
+#if BB_MMU
+#define parse_stream(pstring, heredoc_cnt_ptr, input, end_trigger) \
+	parse_stream(heredoc_cnt_ptr, input, end_trigger)
+#endif
+static struct pipe *parse_stream(char **pstring,
+		int *heredoc_cnt_ptr,
+		struct in_str *input,
+		int end_trigger);
+
+/* Returns number of heredocs not yet consumed,
+ * or -1 on error.
+ */
+static int parse_group(struct parse_context *ctx,
+		struct in_str *input, int ch)
+{
+	/* ctx->word contains characters seen prior to ( or {.
+	 * Typically it's empty, but for function defs,
+	 * it contains function name (without '()'). */
+#if BB_MMU
+# define as_string NULL
+#else
+	char *as_string = NULL;
+#endif
+	struct pipe *pipe_list;
+	int heredoc_cnt = 0;
+	int endch;
+	struct command *command = ctx->command;
+
+	debug_printf_parse("parse_group entered\n");
+#if ENABLE_HUSH_FUNCTIONS
+	if (ch == '(' && !ctx->word.has_quoted_part) {
+		if (ctx->word.length)
+			if (done_word(ctx))
+				return -1;
+		if (!command->argv)
+			goto skip; /* (... */
+		if (command->argv[1]) { /* word word ... (... */
+			syntax_error_unexpected_ch('(');
+			return -1;
+		}
+		/* it is "word(..." or "word (..." */
+		do
+			ch = i_getch(input);
+		while (ch == ' ' || ch == '\t');
+		if (ch != ')') {
+			syntax_error_unexpected_ch(ch);
+			return -1;
+		}
+		nommu_addchr(&ctx->as_string, ch);
+		do
+			ch = i_getch(input);
+		while (ch == ' ' || ch == '\t' || ch == '\n');
+		if (ch != '{' && ch != '(') {
+			syntax_error_unexpected_ch(ch);
+			return -1;
+		}
+		nommu_addchr(&ctx->as_string, ch);
+		command->cmd_type = CMD_FUNCDEF;
+		goto skip;
+	}
+#endif
+
+#if 0 /* Prevented by caller */
+	if (command->argv /* word [word]{... */
+	 || ctx->word.length /* word{... */
+	 || ctx->word.has_quoted_part /* ""{... */
+	) {
+		syntax_error(NULL);
+		debug_printf_parse("parse_group return -1: "
+			"syntax error, groups and arglists don't mix\n");
+		return -1;
+	}
+#endif
+
+ IF_HUSH_FUNCTIONS(skip:)
+
+	endch = '}';
+	if (ch == '(') {
+		endch = ')';
+		IF_HUSH_FUNCTIONS(if (command->cmd_type != CMD_FUNCDEF))
+			command->cmd_type = CMD_SUBSHELL;
+	} else {
+		/* bash does not allow "{echo...", requires whitespace */
+		ch = i_peek(input);
+		if (ch != ' ' && ch != '\t' && ch != '\n'
+		 && ch != '('	/* but "{(..." is allowed (without whitespace) */
+		) {
+			syntax_error_unexpected_ch(ch);
+			return -1;
+		}
+		if (ch != '(') {
+			ch = i_getch(input);
+			nommu_addchr(&ctx->as_string, ch);
+		}
+	}
+
+	debug_printf_heredoc("calling parse_stream, heredoc_cnt:%d\n", heredoc_cnt);
+	pipe_list = parse_stream(&as_string, &heredoc_cnt, input, endch);
+	debug_printf_heredoc("parse_stream returned: heredoc_cnt:%d\n", heredoc_cnt);
+#if !BB_MMU
+	if (as_string)
+		o_addstr(&ctx->as_string, as_string);
+#endif
+
+	/* empty ()/{} or parse error? */
+	if (!pipe_list || pipe_list == ERR_PTR) {
+		/* parse_stream already emitted error msg */
+		if (!BB_MMU)
+			free(as_string);
+		debug_printf_parse("parse_group return -1: "
+			"parse_stream returned %p\n", pipe_list);
+		return -1;
+	}
+#if !BB_MMU
+	as_string[strlen(as_string) - 1] = '\0'; /* plink ')' or '}' */
+	command->group_as_string = as_string;
+	debug_printf_parse("end of group, remembering as:'%s'\n",
+			command->group_as_string);
+#endif
+
+#if ENABLE_HUSH_FUNCTIONS
+	/* Convert "f() (cmds)" to "f() {(cmds)}" */
+	if (command->cmd_type == CMD_FUNCDEF && endch == ')') {
+		struct command *cmd2;
+
+		cmd2 = xzalloc(sizeof(*cmd2));
+		cmd2->cmd_type = CMD_SUBSHELL;
+		cmd2->group = pipe_list;
+# if !BB_MMU
+//UNTESTED!
+		cmd2->group_as_string = command->group_as_string;
+		command->group_as_string = xasprintf("(%s)", command->group_as_string);
+# endif
+
+		pipe_list = new_pipe();
+		pipe_list->cmds = cmd2;
+		pipe_list->num_cmds = 1;
+	}
+#endif
+
+	command->group = pipe_list;
+
+	debug_printf_parse("parse_group return %d\n", heredoc_cnt);
+	return heredoc_cnt;
+	/* command remains "open", available for possible redirects */
+#undef as_string
+}
+
+#if ENABLE_HUSH_TICK || ENABLE_FEATURE_SH_MATH || ENABLE_HUSH_DOLLAR_OPS
+/* Subroutines for copying $(...) and `...` things */
+/* '...' */
+static int add_till_single_quote(o_string *dest, struct in_str *input)
+{
+	while (1) {
+		int ch = i_getch(input);
+		if (ch == EOF) {
+			syntax_error_unterm_ch('\'');
+			return 0;
+		}
+		if (ch == '\'')
+			return 1;
+		o_addchr(dest, ch);
+	}
+}
+static int add_till_single_quote_dquoted(o_string *dest, struct in_str *input)
+{
+	while (1) {
+		int ch = i_getch(input);
+		if (ch == EOF) {
+			syntax_error_unterm_ch('\'');
+			return 0;
+		}
+		if (ch == '\'')
+			return 1;
+		o_addqchr(dest, ch);
+	}
+}
+/* "...\"...`..`...." - do we need to handle "...$(..)..." too? */
+static int add_till_backquote(o_string *dest, struct in_str *input, int in_dquote);
+static int add_till_double_quote(o_string *dest, struct in_str *input)
+{
+	while (1) {
+		int ch = i_getch(input);
+		if (ch == EOF) {
+			syntax_error_unterm_ch('"');
+			return 0;
+		}
+		if (ch == '"')
+			return 1;
+		if (ch == '\\') {  /* \x. Copy both chars. */
+			o_addchr(dest, ch);
+			ch = i_getch(input);
+		}
+		o_addchr(dest, ch);
+		if (ch == '`') {
+			if (!add_till_backquote(dest, input, /*in_dquote:*/ 1))
+				return 0;
+			o_addchr(dest, ch);
+			continue;
+		}
+		//if (ch == '$') ...
+	}
+}
+/* Process `cmd` - copy contents until "`" is seen. Complicated by
+ * \` quoting.
+ * "Within the backquoted style of command substitution, backslash
+ * shall retain its literal meaning, except when followed by: '$', '`', or '\'.
+ * The search for the matching backquote shall be satisfied by the first
+ * backquote found without a preceding backslash; during this search,
+ * if a non-escaped backquote is encountered within a shell comment,
+ * a here-document, an embedded command substitution of the $(command)
+ * form, or a quoted string, undefined results occur. A single-quoted
+ * or double-quoted string that begins, but does not end, within the
+ * "`...`" sequence produces undefined results."
+ * Example                               Output
+ * echo `echo '\'TEST\`echo ZZ\`BEST`    \TESTZZBEST
+ */
+static int add_till_backquote(o_string *dest, struct in_str *input, int in_dquote)
+{
+	while (1) {
+		int ch = i_getch(input);
+		if (ch == '`')
+			return 1;
+		if (ch == '\\') {
+			/* \x. Copy both unless it is \`, \$, \\ and maybe \" */
+			ch = i_getch(input);
+			if (ch != '`'
+			 && ch != '$'
+			 && ch != '\\'
+			 && (!in_dquote || ch != '"')
+			) {
+				o_addchr(dest, '\\');
+			}
+		}
+		if (ch == EOF) {
+			syntax_error_unterm_ch('`');
+			return 0;
+		}
+		o_addchr(dest, ch);
+	}
+}
+/* Process $(cmd) - copy contents until ")" is seen. Complicated by
+ * quoting and nested ()s.
+ * "With the $(command) style of command substitution, all characters
+ * following the open parenthesis to the matching closing parenthesis
+ * constitute the command. Any valid shell script can be used for command,
+ * except a script consisting solely of redirections which produces
+ * unspecified results."
+ * Example                              Output
+ * echo $(echo '(TEST)' BEST)           (TEST) BEST
+ * echo $(echo 'TEST)' BEST)            TEST) BEST
+ * echo $(echo \(\(TEST\) BEST)         ((TEST) BEST
+ *
+ * Also adapted to eat ${var%...} and $((...)) constructs, since ... part
+ * can contain arbitrary constructs, just like $(cmd).
+ * In bash compat mode, it needs to also be able to stop on ':' or '/'
+ * for ${var:N[:M]} and ${var/P[/R]} parsing.
+ */
+#define DOUBLE_CLOSE_CHAR_FLAG 0x80
+static int add_till_closing_bracket(o_string *dest, struct in_str *input, unsigned end_ch)
+{
+	int ch;
+	char dbl = end_ch & DOUBLE_CLOSE_CHAR_FLAG;
+# if BASH_SUBSTR || BASH_PATTERN_SUBST
+	char end_char2 = end_ch >> 8;
+# endif
+	end_ch &= (DOUBLE_CLOSE_CHAR_FLAG - 1);
+
+# if ENABLE_HUSH_INTERACTIVE
+	G.promptmode = 1; /* PS2 */
+# endif
+	debug_printf_prompt("%s promptmode=%d\n", __func__, G.promptmode);
+
+	while (1) {
+		ch = i_getch(input);
+		if (ch == EOF) {
+			syntax_error_unterm_ch(end_ch);
+			return 0;
+		}
+		if (ch == end_ch
+# if BASH_SUBSTR || BASH_PATTERN_SUBST
+		 || ch == end_char2
+# endif
+		) {
+			if (!dbl)
+				break;
+			/* we look for closing )) of $((EXPR)) */
+			if (i_peek_and_eat_bkslash_nl(input) == end_ch) {
+				i_getch(input); /* eat second ')' */
+				break;
+			}
+		}
+		o_addchr(dest, ch);
+		//bb_error_msg("%s:o_addchr('%c')", __func__, ch);
+		if (ch == '(' || ch == '{') {
+			ch = (ch == '(' ? ')' : '}');
+			if (!add_till_closing_bracket(dest, input, ch))
+				return 0;
+			o_addchr(dest, ch);
+			continue;
+		}
+		if (ch == '\'') {
+			if (!add_till_single_quote(dest, input))
+				return 0;
+			o_addchr(dest, ch);
+			continue;
+		}
+		if (ch == '"') {
+			if (!add_till_double_quote(dest, input))
+				return 0;
+			o_addchr(dest, ch);
+			continue;
+		}
+		if (ch == '`') {
+			if (!add_till_backquote(dest, input, /*in_dquote:*/ 0))
+				return 0;
+			o_addchr(dest, ch);
+			continue;
+		}
+		if (ch == '\\') {
+			/* \x. Copy verbatim. Important for  \(, \) */
+			ch = i_getch(input);
+			if (ch == EOF) {
+				syntax_error_unterm_ch(end_ch);
+				return 0;
+			}
+# if 0
+			if (ch == '\n') {
+				/* "backslash+newline", ignore both */
+				o_delchr(dest); /* undo insertion of '\' */
+				continue;
+			}
+# endif
+			o_addchr(dest, ch);
+			//bb_error_msg("%s:o_addchr('%c') after '\\'", __func__, ch);
+			continue;
+		}
+	}
+	debug_printf_parse("%s return '%s' ch:'%c'\n", __func__, dest->data, ch);
+	return ch;
+}
+#endif /* ENABLE_HUSH_TICK || ENABLE_FEATURE_SH_MATH || ENABLE_HUSH_DOLLAR_OPS */
+
+#if BASH_DOLLAR_SQUOTE
+/* Return code: 1 for "found and parsed", 0 for "seen something else" */
+# if BB_MMU
+#define parse_dollar_squote(as_string, dest, input) \
+	parse_dollar_squote(dest, input)
+#define as_string NULL
+# endif
+static int parse_dollar_squote(o_string *as_string, o_string *dest, struct in_str *input)
+{
+	int start;
+	int ch = i_peek_and_eat_bkslash_nl(input);  /* first character after the $ */
+	debug_printf_parse("parse_dollar_squote entered: ch='%c'\n", ch);
+	if (ch != '\'')
+		return 0;
+
+	dest->has_quoted_part = 1;
+	start = dest->length;
+
+	ch = i_getch(input); /* eat ' */
+	nommu_addchr(as_string, ch);
+	while (1) {
+		ch = i_getch(input);
+		nommu_addchr(as_string, ch);
+		if (ch == EOF) {
+			syntax_error_unterm_ch('\'');
+			return 0;
+		}
+		if (ch == '\'')
+			break;
+		if (ch == SPECIAL_VAR_SYMBOL) {
+			/* Convert raw ^C to corresponding special variable reference */
+			o_addchr(dest, SPECIAL_VAR_SYMBOL);
+			o_addchr(dest, SPECIAL_VAR_QUOTED_SVS);
+			/* will addchr() another SPECIAL_VAR_SYMBOL (see after the if() block) */
+		} else if (ch == '\\') {
+			static const char C_escapes[] ALIGN1 = "nrbtfav""x\\01234567";
+
+			ch = i_getch(input);
+			nommu_addchr(as_string, ch);
+			if (strchr(C_escapes, ch)) {
+				char buf[4];
+				char *p = buf;
+				int cnt = 2;
+
+				buf[0] = ch;
+				if ((unsigned char)(ch - '0') <= 7) { /* \ooo */
+					do {
+						ch = i_peek(input);
+						if ((unsigned char)(ch - '0') > 7)
+							break;
+						*++p = ch = i_getch(input);
+						nommu_addchr(as_string, ch);
+					} while (--cnt != 0);
+				} else if (ch == 'x') { /* \xHH */
+					do {
+						ch = i_peek(input);
+						if (!isxdigit(ch))
+							break;
+						*++p = ch = i_getch(input);
+						nommu_addchr(as_string, ch);
+					} while (--cnt != 0);
+					if (cnt == 2) { /* \x but next char is "bad" */
+						ch = 'x';
+						goto unrecognized;
+					}
+				} /* else simple seq like \\ or \t */
+				*++p = '\0';
+				p = buf;
+				ch = bb_process_escape_sequence((void*)&p);
+				//bb_error_msg("buf:'%s' ch:%x", buf, ch);
+				if (ch == '\0')
+					continue; /* bash compat: $'...\0...' emits nothing */
+			} else { /* unrecognized "\z": encode both chars unless ' or " */
+				if (ch != '\'' && ch != '"') {
+ unrecognized:
+					o_addqchr(dest, '\\');
+				}
+			}
+		} /* if (\...) */
+		o_addqchr(dest, ch);
+	}
+
+	if (dest->length == start) {
+		/* $'', $'\0', $'\000\x00' and the like */
+		o_addchr(dest, SPECIAL_VAR_SYMBOL);
+		o_addchr(dest, SPECIAL_VAR_SYMBOL);
+	}
+
+	return 1;
+# undef as_string
+}
+#else
+# #define parse_dollar_squote(as_string, dest, input) 0
+#endif /* BASH_DOLLAR_SQUOTE */
+
+/* Return code: 0 for OK, 1 for syntax error */
+#if BB_MMU
+#define parse_dollar(as_string, dest, input, quote_mask) \
+	parse_dollar(dest, input, quote_mask)
+#define as_string NULL
+#endif
+static int parse_dollar(o_string *as_string,
+		o_string *dest,
+		struct in_str *input, unsigned char quote_mask)
+{
+	int ch = i_peek_and_eat_bkslash_nl(input);  /* first character after the $ */
+
+	debug_printf_parse("parse_dollar entered: ch='%c' quote_mask:0x%x\n", ch, quote_mask);
+	if (isalpha(ch)) {
+ make_var:
+		ch = i_getch(input);
+		nommu_addchr(as_string, ch);
+ /*make_var1:*/
+		o_addchr(dest, SPECIAL_VAR_SYMBOL);
+		while (1) {
+			debug_printf_parse(": '%c'\n", ch);
+			o_addchr(dest, ch | quote_mask);
+			quote_mask = 0;
+			ch = i_peek_and_eat_bkslash_nl(input);
+			if (!isalnum(ch) && ch != '_') {
+				/* End of variable name reached */
+				break;
+			}
+			ch = i_getch(input);
+			nommu_addchr(as_string, ch);
+		}
+		o_addchr(dest, SPECIAL_VAR_SYMBOL);
+	} else if (isdigit(ch)) {
+ make_one_char_var:
+		ch = i_getch(input);
+		nommu_addchr(as_string, ch);
+		o_addchr(dest, SPECIAL_VAR_SYMBOL);
+		debug_printf_parse(": '%c'\n", ch);
+		o_addchr(dest, ch | quote_mask);
+		o_addchr(dest, SPECIAL_VAR_SYMBOL);
+	} else switch (ch) {
+	case '$': /* pid */
+	case '!': /* last bg pid */
+	case '?': /* last exit code */
+	case '#': /* number of args */
+	case '*': /* args */
+	case '@': /* args */
+	case '-': /* $- option flags set by set builtin or shell options (-i etc) */
+		goto make_one_char_var;
+	case '{': {
+		char len_single_ch;
+
+		o_addchr(dest, SPECIAL_VAR_SYMBOL);
+
+		ch = i_getch(input); /* eat '{' */
+		nommu_addchr(as_string, ch);
+
+		ch = i_getch_and_eat_bkslash_nl(input); /* first char after '{' */
+		/* It should be ${?}, or ${#var},
+		 * or even ${?+subst} - operator acting on a special variable,
+		 * or the beginning of variable name.
+		 */
+		if (ch == EOF
+		 || (!strchr(_SPECIAL_VARS_STR, ch) && !isalnum(ch)) /* not one of those */
+		) {
+ bad_dollar_syntax:
+			syntax_error_unterm_str("${name}");
+			debug_printf_parse("parse_dollar return 0: unterminated ${name}\n");
+			return 0;
+		}
+		nommu_addchr(as_string, ch);
+		len_single_ch = ch;
+		ch |= quote_mask;
+
+		/* It's possible to just call add_till_closing_bracket() at this point.
+		 * However, this regresses some of our testsuite cases
+		 * which check invalid constructs like ${%}.
+		 * Oh well... let's check that the var name part is fine... */
+
+		if (isdigit(len_single_ch)
+		 || (len_single_ch == '#' && isdigit(i_peek_and_eat_bkslash_nl(input)))
+		) {
+			/* Execution engine uses plain xatoi_positive()
+			 * to interpret ${NNN} and {#NNN},
+			 * check syntax here in the parser.
+			 * (bash does not support expressions in ${#NN},
+			 * e.g. ${#$var} and {#1:+WORD} are not supported).
+			 */
+			unsigned cnt = 9; /* max 9 digits for ${NN} and 8 for {#NN} */
+			while (1) {
+				o_addchr(dest, ch);
+				debug_printf_parse(": '%c'\n", ch);
+				ch = i_getch_and_eat_bkslash_nl(input);
+				nommu_addchr(as_string, ch);
+				if (ch == '}')
+					break;
+				if (--cnt == 0)
+					goto bad_dollar_syntax;
+				if (len_single_ch != '#' && strchr(VAR_SUBST_OPS, ch))
+					/* ${NN<op>...} is valid */
+					goto eat_until_closing;
+				if (!isdigit(ch))
+					goto bad_dollar_syntax;
+			}
+		} else
+		while (1) {
+			unsigned pos;
+
+			o_addchr(dest, ch);
+			debug_printf_parse(": '%c'\n", ch);
+
+			ch = i_getch(input);
+			nommu_addchr(as_string, ch);
+			if (ch == '}')
+				break;
+			if (!isalnum(ch) && ch != '_') {
+				unsigned end_ch;
+				unsigned char last_ch;
+				/* handle parameter expansions
+				 * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_02
+				 */
+				if (!strchr(VAR_SUBST_OPS, ch)) { /* ${var<bad_char>... */
+					if (len_single_ch != '#'
+					/*|| !strchr(SPECIAL_VARS_STR, ch) - disallow errors like ${#+} ? */
+					 || i_peek(input) != '}'
+					) {
+						goto bad_dollar_syntax;
+					}
+					/* else: it's "length of C" ${#C} op,
+					 * where C is a single char
+					 * special var name, e.g. ${#!}.
+					 */
+				}
+ eat_until_closing:
+				/* Eat everything until closing '}' (or ':') */
+				end_ch = '}';
+				if (BASH_SUBSTR
+				 && ch == ':'
+				 && !strchr(MINUS_PLUS_EQUAL_QUESTION, i_peek(input))
+				) {
+					/* It's ${var:N[:M]} thing */
+					end_ch = '}' * 0x100 + ':';
+				}
+				if (BASH_PATTERN_SUBST
+				 && ch == '/'
+				) {
+					/* It's ${var/[/]pattern[/repl]} thing */
+					if (i_peek(input) == '/') { /* ${var//pattern[/repl]}? */
+						i_getch(input);
+						nommu_addchr(as_string, '/');
+						ch = '\\';
+					}
+					end_ch = '}' * 0x100 + '/';
+				}
+				o_addchr(dest, ch);
+				/* The pattern can't be empty.
+				 * IOW: if the first char after "${v//" is a slash,
+				 * it does not terminate the pattern - it's the first char of the pattern:
+				 *  v=/dev/ram; echo ${v////-}  prints -dev-ram (pattern is "/")
+				 *  v=/dev/ram; echo ${v///r/-} prints /dev-am  (pattern is "/r")
+				 */
+				if (i_peek(input) == '/') {
+					o_addchr(dest, i_getch(input));
+				}
+ again:
+				if (!BB_MMU)
+					pos = dest->length;
+#if ENABLE_HUSH_DOLLAR_OPS
+				last_ch = add_till_closing_bracket(dest, input, end_ch);
+				if (last_ch == 0) /* error? */
+					return 0;
+#else
+# error Simple code to only allow ${var} is not implemented
+#endif
+				if (as_string) {
+					o_addstr(as_string, dest->data + pos);
+					o_addchr(as_string, last_ch);
+				}
+
+				if ((BASH_SUBSTR || BASH_PATTERN_SUBST)
+					 && (end_ch & 0xff00)
+				) {
+					/* close the first block: */
+					o_addchr(dest, SPECIAL_VAR_SYMBOL);
+					/* while parsing N from ${var:N[:M]}
+					 * or pattern from ${var/[/]pattern[/repl]} */
+					if ((end_ch & 0xff) == last_ch) {
+						/* got ':' or '/'- parse the rest */
+						end_ch = '}';
+						goto again;
+					}
+					/* got '}' */
+					if (BASH_SUBSTR && end_ch == '}' * 0x100 + ':') {
+						/* it's ${var:N} - emulate :999999999 */
+						o_addstr(dest, "999999999");
+					} /* else: it's ${var/[/]pattern} */
+				}
+				break;
+			}
+			len_single_ch = 0; /* it can't be ${#C} op */
+		}
+		o_addchr(dest, SPECIAL_VAR_SYMBOL);
+		break;
+	}
+#if ENABLE_FEATURE_SH_MATH || ENABLE_HUSH_TICK
+	case '(': {
+		unsigned pos;
+
+		ch = i_getch(input);
+		nommu_addchr(as_string, ch);
+# if ENABLE_FEATURE_SH_MATH
+		if (i_peek_and_eat_bkslash_nl(input) == '(') {
+			ch = i_getch(input);
+			nommu_addchr(as_string, ch);
+			o_addchr(dest, SPECIAL_VAR_SYMBOL);
+			o_addchr(dest, quote_mask | '+');
+			if (!BB_MMU)
+				pos = dest->length;
+			if (!add_till_closing_bracket(dest, input, ')' | DOUBLE_CLOSE_CHAR_FLAG))
+				return 0; /* error */
+			if (as_string) {
+				o_addstr(as_string, dest->data + pos);
+				o_addchr(as_string, ')');
+				o_addchr(as_string, ')');
+			}
+			o_addchr(dest, SPECIAL_VAR_SYMBOL);
+			break;
+		}
+# endif
+# if ENABLE_HUSH_TICK
+		o_addchr(dest, SPECIAL_VAR_SYMBOL);
+		o_addchr(dest, quote_mask | '`');
+		if (!BB_MMU)
+			pos = dest->length;
+		if (!add_till_closing_bracket(dest, input, ')'))
+			return 0; /* error */
+		if (as_string) {
+			o_addstr(as_string, dest->data + pos);
+			o_addchr(as_string, ')');
+		}
+		o_addchr(dest, SPECIAL_VAR_SYMBOL);
+# endif
+		break;
+	}
+#endif
+	case '_':
+		goto make_var;
+#if 0
+	/* TODO: $_: */
+	/* $_ Shell or shell script name; or last argument of last command
+	 * (if last command wasn't a pipe; if it was, bash sets $_ to "");
+	 * but in command's env, set to full pathname used to invoke it */
+		ch = i_getch(input);
+		nommu_addchr(as_string, ch);
+		ch = i_peek_and_eat_bkslash_nl(input);
+		if (isalnum(ch)) { /* it's $_name or $_123 */
+			ch = '_';
+			goto make_var1;
+		}
+		/* else: it's $_ */
+#endif
+	default:
+		o_addQchr(dest, '$');
+	}
+	debug_printf_parse("parse_dollar return 1 (ok)\n");
+	return 1;
+#undef as_string
+}
+
+#if BB_MMU
+#define encode_string(as_string, dest, input, dquote_end) \
+	encode_string(dest, input, dquote_end)
+#define as_string NULL
+#endif
+static int encode_string(o_string *as_string,
+		o_string *dest,
+		struct in_str *input,
+		int dquote_end)
+{
+	int ch;
+	int next;
+
+ again:
+	ch = i_getch(input);
+	if (ch != EOF)
+		nommu_addchr(as_string, ch);
+	if (ch == dquote_end) { /* may be only '"' or EOF */
+		debug_printf_parse("encode_string return 1 (ok)\n");
+		return 1;
+	}
+	/* note: can't move it above ch == dquote_end check! */
+	if (ch == EOF) {
+		syntax_error_unterm_ch('"');
+		return 0; /* error */
+	}
+	next = '\0';
+	if (ch != '\n') {
+		next = i_peek(input);
+	}
+	debug_printf_parse("\" ch=%c (%d) escape=%d\n",
+			ch, ch, !!(dest->o_expflags & EXP_FLAG_ESC_GLOB_CHARS));
+	if (ch == '\\') {
+		if (next == EOF) {
+			/* Testcase: in interactive shell a file with
+			 *  echo "unterminated string\<eof>
+			 * is sourced.
+			 */
+			syntax_error_unterm_ch('"');
+			return 0; /* error */
+		}
+		/* bash:
+		 * "The backslash retains its special meaning [in "..."]
+		 * only when followed by one of the following characters:
+		 * $, `, ", \, or <newline>.  A double quote may be quoted
+		 * within double quotes by preceding it with a backslash."
+		 * NB: in (unquoted) heredoc, above does not apply to ",
+		 * therefore we check for it by "next == dquote_end" cond.
+		 */
+		if (next == dquote_end || strchr("$`\\\n", next)) {
+			ch = i_getch(input); /* eat next */
+			if (ch == '\n')
+				goto again; /* skip \<newline> */
+		} /* else: ch remains == '\\', and we double it below: */
+		o_addqchr(dest, ch); /* \c if c is a glob char, else just c */
+		nommu_addchr(as_string, ch);
+		goto again;
+	}
+	if (ch == '$') {
+		//if (parse_dollar_squote(as_string, dest, input))
+		//	goto again;
+		if (!parse_dollar(as_string, dest, input, /*quote_mask:*/ 0x80)) {
+			debug_printf_parse("encode_string return 0: "
+					"parse_dollar returned 0 (error)\n");
+			return 0;
+		}
+		goto again;
+	}
+#if ENABLE_HUSH_TICK
+	if (ch == '`') {
+		//unsigned pos = dest->length;
+		o_addchr(dest, SPECIAL_VAR_SYMBOL);
+		o_addchr(dest, 0x80 | '`');
+		if (!add_till_backquote(dest, input, /*in_dquote:*/ dquote_end == '"'))
+			return 0; /* error */
+		o_addchr(dest, SPECIAL_VAR_SYMBOL);
+		//debug_printf_subst("SUBST RES3 '%s'\n", dest->data + pos);
+		goto again;
+	}
+#endif
+	o_addQchr(dest, ch);
+	if (ch == SPECIAL_VAR_SYMBOL) {
+		/* Convert "^C" to corresponding special variable reference */
+		o_addchr(dest, SPECIAL_VAR_QUOTED_SVS);
+		o_addchr(dest, SPECIAL_VAR_SYMBOL);
+	}
+	goto again;
+#undef as_string
+}
+
+/*
+ * Scan input until EOF or end_trigger char.
+ * Return a list of pipes to execute, or NULL on EOF
+ * or if end_trigger character is met.
+ * On syntax error, exit if shell is not interactive,
+ * reset parsing machinery and start parsing anew,
+ * or return ERR_PTR.
+ */
+static struct pipe *parse_stream(char **pstring,
+		int *heredoc_cnt_ptr,
+		struct in_str *input,
+		int end_trigger)
+{
+	struct parse_context ctx;
+	int heredoc_cnt;
+
+	/* Single-quote triggers a bypass of the main loop until its mate is
+	 * found.  When recursing, quote state is passed in via ctx.word.o_expflags.
+	 */
+	debug_printf_parse("parse_stream entered, end_trigger='%c'\n",
+			end_trigger ? end_trigger : 'X');
+	debug_enter();
+
+	initialize_context(&ctx);
+
+	/* If very first arg is "" or '', ctx.word.data may end up NULL.
+	 * Preventing this:
+	 */
+	ctx.word.data = xzalloc(1); /* start as "", not as NULL */
+
+	/* We used to separate words on $IFS here. This was wrong.
+	 * $IFS is used only for word splitting when $var is expanded,
+	 * here we should use blank chars as separators, not $IFS
+	 */
+
+	heredoc_cnt = 0;
+	while (1) {
+		const char *is_blank;
+		const char *is_special;
+		int ch;
+		int next;
+		int redir_fd;
+		redir_type redir_style;
+
+		ch = i_getch(input);
+		debug_printf_parse(": ch=%c (%d) escape=%d\n",
+				ch, ch, !!(ctx.word.o_expflags & EXP_FLAG_ESC_GLOB_CHARS));
+		if (ch == EOF) {
+			struct pipe *pi;
+
+			if (heredoc_cnt) {
+				syntax_error_unterm_str("here document");
+				goto parse_error_exitcode1;
+			}
+			if (end_trigger == ')') {
+				syntax_error_unterm_ch('(');
+				goto parse_error_exitcode1;
+			}
+			if (end_trigger == '}') {
+				syntax_error_unterm_ch('{');
+				goto parse_error_exitcode1;
+			}
+
+			if (done_word(&ctx)) {
+				goto parse_error_exitcode1;
+			}
+			o_free_and_set_NULL(&ctx.word);
+			done_pipe(&ctx, PIPE_SEQ);
+			pi = ctx.list_head;
+			/* If we got nothing... */
+			/* (this makes bare "&" cmd a no-op.
+			 * bash says: "syntax error near unexpected token '&'") */
+			if (pi->num_cmds == 0
+			IF_HAS_KEYWORDS(&& pi->res_word == RES_NONE)
+			) {
+				free_pipe_list(pi);
+				pi = NULL;
+			}
+#if !BB_MMU
+			debug_printf_parse("as_string1 '%s'\n", ctx.as_string.data);
+			if (pstring)
+				*pstring = ctx.as_string.data;
+			else
+				o_free(&ctx.as_string);
+#endif
+			// heredoc_cnt must be 0 here anyway
+			//if (heredoc_cnt_ptr)
+			//	*heredoc_cnt_ptr = heredoc_cnt;
+			debug_leave();
+			debug_printf_heredoc("parse_stream return heredoc_cnt:%d\n", heredoc_cnt);
+			debug_printf_parse("parse_stream return %p\n", pi);
+			return pi;
+		}
+
+		/* Handle "'" and "\" first, as they won't play nice with
+		 * i_peek_and_eat_bkslash_nl() anyway:
+		 *   echo z\\
+		 * and
+		 *   echo '\
+		 *   '
+		 * would break.
+		 */
+		if (ch == '\\') {
+			ch = i_getch(input);
+			if (ch == '\n')
+				continue; /* drop \<newline>, get next char */
+			nommu_addchr(&ctx.as_string, '\\');
+			if (ch == SPECIAL_VAR_SYMBOL) {
+				nommu_addchr(&ctx.as_string, ch);
+				/* Convert \^C to corresponding special variable reference */
+				goto case_SPECIAL_VAR_SYMBOL;
+			}
+			o_addchr(&ctx.word, '\\');
+			if (ch == EOF) {
+				/* Testcase: eval 'echo Ok\' */
+				/* bash-4.3.43 was removing backslash,
+				 * but 4.4.19 retains it, most other shells too
+				 */
+				continue; /* get next char */
+			}
+			/* Example: echo Hello \2>file
+			 * we need to know that word 2 is quoted
+			 */
+			ctx.word.has_quoted_part = 1;
+			nommu_addchr(&ctx.as_string, ch);
+			o_addchr(&ctx.word, ch);
+			continue; /* get next char */
+		}
+		nommu_addchr(&ctx.as_string, ch);
+		if (ch == '\'') {
+			ctx.word.has_quoted_part = 1;
+			next = i_getch(input);
+			if (next == '\'' && !ctx.pending_redirect)
+				goto insert_empty_quoted_str_marker;
+
+			ch = next;
+			while (1) {
+				if (ch == EOF) {
+					syntax_error_unterm_ch('\'');
+					goto parse_error_exitcode1;
+				}
+				nommu_addchr(&ctx.as_string, ch);
+				if (ch == '\'')
+					break;
+				if (ch == SPECIAL_VAR_SYMBOL) {
+					/* Convert raw ^C to corresponding special variable reference */
+					o_addchr(&ctx.word, SPECIAL_VAR_SYMBOL);
+					o_addchr(&ctx.word, SPECIAL_VAR_QUOTED_SVS);
+				}
+				o_addqchr(&ctx.word, ch);
+				ch = i_getch(input);
+			}
+			continue; /* get next char */
+		}
+
+		next = '\0';
+		if (ch != '\n')
+			next = i_peek_and_eat_bkslash_nl(input);
+
+		is_special = "{}<>&|();#" /* special outside of "str" */
+				"$\"" IF_HUSH_TICK("`") /* always special */
+				SPECIAL_VAR_SYMBOL_STR;
+#if defined(CMD_TEST2_SINGLEWORD_NOGLOB)
+		if (ctx.command->cmd_type == CMD_TEST2_SINGLEWORD_NOGLOB) {
+			/* In [[ ]], {}<>&|() are not special */
+			is_special += 8;
+		} else
+#endif
+		/* Are { and } special here? */
+		if (ctx.command->argv /* word [word]{... - non-special */
+		 || ctx.word.length       /* word{... - non-special */
+		 || ctx.word.has_quoted_part     /* ""{... - non-special */
+		 || (next != ';'             /* }; - special */
+		    && next != ')'           /* }) - special */
+		    && next != '('           /* {( - special */
+		    && next != '&'           /* }& and }&& ... - special */
+		    && next != '|'           /* }|| ... - special */
+		    && !strchr(defifs, next) /* {word - non-special */
+		    )
+		) {
+			/* They are not special, skip "{}" */
+			is_special += 2;
+		}
+		is_special = strchr(is_special, ch);
+		is_blank = strchr(defifs, ch);
+
+		if (!is_special && !is_blank) { /* ordinary char */
+ ordinary_char:
+			o_addQchr(&ctx.word, ch);
+			if ((ctx.is_assignment == MAYBE_ASSIGNMENT
+			    || ctx.is_assignment == WORD_IS_KEYWORD)
+			 && ch == '='
+			 && endofname(ctx.word.data)[0] == '='
+			) {
+				ctx.is_assignment = DEFINITELY_ASSIGNMENT;
+				debug_printf_parse("ctx.is_assignment='%s'\n", assignment_flag[ctx.is_assignment]);
+			}
+			continue;
+		}
+
+		if (is_blank) {
+#if ENABLE_HUSH_LINENO_VAR
+/* Case:
+ * "while ...; do<whitespace><newline>
+ *	cmd ..."
+ * would think that "cmd" starts in <whitespace> -
+ * i.e., at the previous line.
+ * We need to skip all whitespace before newlines.
+ */
+			while (ch != '\n') {
+				next = i_peek(input);
+				if (next != ' ' && next != '\t' && next != '\n')
+					break; /* next char is not ws */
+				ch = i_getch(input);
+			}
+			/* ch == last eaten whitespace char */
+#endif
+			if (done_word(&ctx)) {
+				goto parse_error_exitcode1;
+			}
+			if (ch == '\n') {
+				/* Is this a case when newline is simply ignored?
+				 * Some examples:
+				 * "cmd | <newline> cmd ..."
+				 * "case ... in <newline> word) ..."
+				 */
+				if (IS_NULL_CMD(ctx.command)
+				 && ctx.word.length == 0
+				 && !ctx.word.has_quoted_part
+				 && heredoc_cnt == 0
+				) {
+					/* This newline can be ignored. But...
+					 * Without check #1, interactive shell
+					 * ignores even bare <newline>,
+					 * and shows the continuation prompt:
+					 * ps1_prompt$ <enter>
+					 * ps2> _   <=== wrong, should be ps1
+					 * Without check #2, "cmd & <newline>"
+					 * is similarly mistreated.
+					 * (BTW, this makes "cmd & cmd"
+					 * and "cmd && cmd" non-orthogonal.
+					 * Really, ask yourself, why
+					 * "cmd && <newline>" doesn't start
+					 * cmd but waits for more input?
+					 * The only reason is that it might be
+					 * a "cmd1 && <nl> cmd2 &" construct,
+					 * cmd1 may need to run in BG).
+					 */
+					struct pipe *pi = ctx.list_head;
+					if (pi->num_cmds != 0       /* check #1 */
+					 && pi->followup != PIPE_BG /* check #2 */
+					) {
+						continue;
+					}
+				}
+				/* Treat newline as a command separator. */
+				done_pipe(&ctx, PIPE_SEQ);
+				debug_printf_heredoc("heredoc_cnt:%d\n", heredoc_cnt);
+				if (heredoc_cnt) {
+					heredoc_cnt = fetch_heredocs(&ctx.as_string, ctx.list_head, heredoc_cnt, input);
+					if (heredoc_cnt != 0)
+						goto parse_error_exitcode1;
+				}
+				ctx.is_assignment = MAYBE_ASSIGNMENT;
+				debug_printf_parse("ctx.is_assignment='%s'\n", assignment_flag[ctx.is_assignment]);
+				ch = ';';
+				/* note: if (is_blank) continue;
+				 * will still trigger for us */
+			}
+		}
+
+		/* "cmd}" or "cmd }..." without semicolon or &:
+		 * } is an ordinary char in this case, even inside { cmd; }
+		 * Pathological example: { ""}; } should exec "}" cmd
+		 */
+		if (ch == '}') {
+			if (ctx.word.length != 0 /* word} */
+			 || ctx.word.has_quoted_part    /* ""} */
+			) {
+				goto ordinary_char;
+			}
+			if (!IS_NULL_CMD(ctx.command)) { /* cmd } */
+				/* Generally, there should be semicolon: "cmd; }"
+				 * However, bash allows to omit it if "cmd" is
+				 * a group. Examples:
+				 * { { echo 1; } }
+				 * {(echo 1)}
+				 * { echo 0 >&2 | { echo 1; } }
+				 * { while false; do :; done }
+				 * { case a in b) ;; esac }
+				 */
+				if (ctx.command->group)
+					goto term_group;
+				goto ordinary_char;
+			}
+			if (!IS_NULL_PIPE(ctx.pipe)) /* cmd | } */
+				/* Can't be an end of {cmd}, skip the check */
+				goto skip_end_trigger;
+			/* else: } does terminate a group */
+		}
+ term_group:
+		if (end_trigger && end_trigger == ch
+		 && (ch != ';' || heredoc_cnt == 0)
+#if ENABLE_HUSH_CASE
+		 && (ch != ')'
+		    || ctx.ctx_res_w != RES_MATCH
+		    || (!ctx.word.has_quoted_part && strcmp(ctx.word.data, "esac") == 0)
+		    )
+#endif
+		) {
+			if (done_word(&ctx)) {
+				goto parse_error_exitcode1;
+			}
+			done_pipe(&ctx, PIPE_SEQ);
+			ctx.is_assignment = MAYBE_ASSIGNMENT;
+			debug_printf_parse("ctx.is_assignment='%s'\n", assignment_flag[ctx.is_assignment]);
+			/* Do we sit outside of any if's, loops or case's? */
+			if (!HAS_KEYWORDS
+			IF_HAS_KEYWORDS(|| (ctx.ctx_res_w == RES_NONE && ctx.old_flag == 0))
+			) {
+				o_free_and_set_NULL(&ctx.word);
+#if !BB_MMU
+				debug_printf_parse("as_string2 '%s'\n", ctx.as_string.data);
+				if (pstring)
+					*pstring = ctx.as_string.data;
+				else
+					o_free(&ctx.as_string);
+#endif
+				if (ch != ';' && IS_NULL_PIPE(ctx.list_head)) {
+					/* Example: bare "{ }", "()" */
+					G.last_exitcode = 2; /* bash compat */
+					syntax_error_unexpected_ch(ch);
+					goto parse_error;
+				}
+				if (heredoc_cnt_ptr)
+					*heredoc_cnt_ptr = heredoc_cnt;
+				debug_printf_heredoc("parse_stream return heredoc_cnt:%d\n", heredoc_cnt);
+				debug_printf_parse("parse_stream return %p: "
+						"end_trigger char found\n",
+						ctx.list_head);
+				debug_leave();
+				return ctx.list_head;
+			}
+		}
+
+		if (is_blank)
+			continue;
+
+		/* Catch <, > before deciding whether this word is
+		 * an assignment. a=1 2>z b=2: b=2 is still assignment */
+		switch (ch) {
+		case '>':
+			redir_fd = redirect_opt_num(&ctx.word);
+			if (done_word(&ctx)) {
+				goto parse_error_exitcode1;
+			}
+			redir_style = REDIRECT_OVERWRITE;
+			if (next == '>') {
+				redir_style = REDIRECT_APPEND;
+				ch = i_getch(input);
+				nommu_addchr(&ctx.as_string, ch);
+			}
+#if 0
+			else if (next == '(') {
+				syntax_error(">(process) not supported");
+				goto parse_error_exitcode1;
+			}
+#endif
+			if (parse_redirect(&ctx, redir_fd, redir_style, input))
+				goto parse_error_exitcode1;
+			continue; /* get next char */
+		case '<':
+			redir_fd = redirect_opt_num(&ctx.word);
+			if (done_word(&ctx)) {
+				goto parse_error_exitcode1;
+			}
+			redir_style = REDIRECT_INPUT;
+			if (next == '<') {
+				redir_style = REDIRECT_HEREDOC;
+				heredoc_cnt++;
+				debug_printf_heredoc("++heredoc_cnt=%d\n", heredoc_cnt);
+				ch = i_getch(input);
+				nommu_addchr(&ctx.as_string, ch);
+			} else if (next == '>') {
+				redir_style = REDIRECT_IO;
+				ch = i_getch(input);
+				nommu_addchr(&ctx.as_string, ch);
+			}
+#if 0
+			else if (next == '(') {
+				syntax_error("<(process) not supported");
+				goto parse_error_exitcode1;
+			}
+#endif
+			if (parse_redirect(&ctx, redir_fd, redir_style, input))
+				goto parse_error_exitcode1;
+			continue; /* get next char */
+		case '#':
+			if (ctx.word.length == 0 && !ctx.word.has_quoted_part) {
+				/* skip "#comment" */
+				/* note: we do not add it to &ctx.as_string */
+/* TODO: in bash:
+ * comment inside $() goes to the next \n, even inside quoted string (!):
+ * cmd "$(cmd2 #comment)" - syntax error
+ * cmd "`cmd2 #comment`" - ok
+ * We accept both (comment ends where command subst ends, in both cases).
+ */
+				while (1) {
+					ch = i_peek(input);
+					if (ch == '\n') {
+						nommu_addchr(&ctx.as_string, '\n');
+						break;
+					}
+					ch = i_getch(input);
+					if (ch == EOF)
+						break;
+				}
+				continue; /* get next char */
+			}
+			break;
+		}
+ skip_end_trigger:
+
+		if (ctx.is_assignment == MAYBE_ASSIGNMENT
+		 /* check that we are not in word in "a=1 2>word b=1": */
+		 && !ctx.pending_redirect
+		) {
+			/* ch is a special char and thus this word
+			 * cannot be an assignment */
+			ctx.is_assignment = NOT_ASSIGNMENT;
+			debug_printf_parse("ctx.is_assignment='%s'\n", assignment_flag[ctx.is_assignment]);
+		}
+
+		/* Note: nommu_addchr(&ctx.as_string, ch) is already done */
+
+		switch (ch) {
+		case_SPECIAL_VAR_SYMBOL:
+		case SPECIAL_VAR_SYMBOL:
+			/* Convert raw ^C to corresponding special variable reference */
+			o_addchr(&ctx.word, SPECIAL_VAR_SYMBOL);
+			o_addchr(&ctx.word, SPECIAL_VAR_QUOTED_SVS);
+			/* fall through */
+		case '#':
+			/* non-comment #: "echo a#b" etc */
+			o_addchr(&ctx.word, ch);
+			continue; /* get next char */
+		case '$':
+			if (parse_dollar_squote(&ctx.as_string, &ctx.word, input))
+				continue; /* get next char */
+			if (!parse_dollar(&ctx.as_string, &ctx.word, input, /*quote_mask:*/ 0)) {
+				debug_printf_parse("parse_stream parse error: "
+					"parse_dollar returned 0 (error)\n");
+				goto parse_error_exitcode1;
+			}
+			continue; /* get next char */
+		case '"':
+			ctx.word.has_quoted_part = 1;
+			if (next == '"' && !ctx.pending_redirect) {
+				i_getch(input); /* eat second " */
+ insert_empty_quoted_str_marker:
+				nommu_addchr(&ctx.as_string, next);
+				o_addchr(&ctx.word, SPECIAL_VAR_SYMBOL);
+				o_addchr(&ctx.word, SPECIAL_VAR_SYMBOL);
+				continue; /* get next char */
+			}
+			if (ctx.is_assignment == NOT_ASSIGNMENT)
+				ctx.word.o_expflags |= EXP_FLAG_ESC_GLOB_CHARS;
+			if (!encode_string(&ctx.as_string, &ctx.word, input, '"'))
+				goto parse_error_exitcode1;
+			ctx.word.o_expflags &= ~EXP_FLAG_ESC_GLOB_CHARS;
+			continue; /* get next char */
+#if ENABLE_HUSH_TICK
+		case '`': {
+			USE_FOR_NOMMU(unsigned pos;)
+
+			o_addchr(&ctx.word, SPECIAL_VAR_SYMBOL);
+			o_addchr(&ctx.word, '`');
+			USE_FOR_NOMMU(pos = ctx.word.length;)
+			if (!add_till_backquote(&ctx.word, input, /*in_dquote:*/ 0))
+				goto parse_error_exitcode1;
+# if !BB_MMU
+			o_addstr(&ctx.as_string, ctx.word.data + pos);
+			o_addchr(&ctx.as_string, '`');
+# endif
+			o_addchr(&ctx.word, SPECIAL_VAR_SYMBOL);
+			//debug_printf_subst("SUBST RES3 '%s'\n", ctx.word.data + pos);
+			continue; /* get next char */
+		}
+#endif
+		case ';':
+#if ENABLE_HUSH_CASE
+ case_semi:
+#endif
+			if (done_word(&ctx)) {
+				goto parse_error_exitcode1;
+			}
+			done_pipe(&ctx, PIPE_SEQ);
+#if ENABLE_HUSH_CASE
+			/* Eat multiple semicolons, detect
+			 * whether it means something special */
+			while (1) {
+				ch = i_peek_and_eat_bkslash_nl(input);
+				if (ch != ';')
+					break;
+				ch = i_getch(input);
+				nommu_addchr(&ctx.as_string, ch);
+				if (ctx.ctx_res_w == RES_CASE_BODY) {
+					ctx.ctx_dsemicolon = 1;
+					ctx.ctx_res_w = RES_MATCH;
+					break;
+				}
+			}
+#endif
+ new_cmd:
+			/* We just finished a cmd. New one may start
+			 * with an assignment */
+			ctx.is_assignment = MAYBE_ASSIGNMENT;
+			debug_printf_parse("ctx.is_assignment='%s'\n", assignment_flag[ctx.is_assignment]);
+			continue; /* get next char */
+		case '&':
+			if (done_word(&ctx)) {
+				goto parse_error_exitcode1;
+			}
+			if (next == '&') {
+				ch = i_getch(input);
+				nommu_addchr(&ctx.as_string, ch);
+				done_pipe(&ctx, PIPE_AND);
+			} else {
+				done_pipe(&ctx, PIPE_BG);
+			}
+			goto new_cmd;
+		case '|':
+			if (done_word(&ctx)) {
+				goto parse_error_exitcode1;
+			}
+#if ENABLE_HUSH_CASE
+			if (ctx.ctx_res_w == RES_MATCH)
+				break; /* we are in case's "word | word)" */
+#endif
+			if (next == '|') { /* || */
+				ch = i_getch(input);
+				nommu_addchr(&ctx.as_string, ch);
+				done_pipe(&ctx, PIPE_OR);
+			} else {
+				/* we could pick up a file descriptor choice here
+				 * with redirect_opt_num(), but bash doesn't do it.
+				 * "echo foo 2| cat" yields "foo 2". */
+				done_command(&ctx);
+			}
+			goto new_cmd;
+		case '(':
+#if ENABLE_HUSH_CASE
+			/* "case... in [(]word)..." - skip '(' */
+			if (ctx.ctx_res_w == RES_MATCH
+			 && ctx.command->argv == NULL /* not (word|(... */
+			 && ctx.word.length == 0 /* not word(... */
+			 && ctx.word.has_quoted_part == 0 /* not ""(... */
+			) {
+				continue; /* get next char */
+			}
+#endif
+			/* fall through */
+		case '{': {
+			int n = parse_group(&ctx, input, ch);
+			if (n < 0) {
+				goto parse_error_exitcode1;
+			}
+			debug_printf_heredoc("parse_group done, needs heredocs:%d\n", n);
+			heredoc_cnt += n;
+			goto new_cmd;
+		}
+		case ')':
+#if ENABLE_HUSH_CASE
+			if (ctx.ctx_res_w == RES_MATCH)
+				goto case_semi;
+#endif
+		case '}':
+			/* proper use of this character is caught by end_trigger:
+			 * if we see {, we call parse_group(..., end_trigger='}')
+			 * and it will match } earlier (not here). */
+			G.last_exitcode = 2;
+			syntax_error_unexpected_ch(ch);
+			goto parse_error;
+		default:
+			if (HUSH_DEBUG)
+				bb_error_msg_and_die("BUG: unexpected %c", ch);
+		}
+	} /* while (1) */
+
+ parse_error_exitcode1:
+	G.last_exitcode = 1;
+ parse_error:
+	{
+		struct parse_context *pctx;
+		IF_HAS_KEYWORDS(struct parse_context *p2;)
+
+		/* Clean up allocated tree.
+		 * Sample for finding leaks on syntax error recovery path.
+		 * Run it from interactive shell, watch pmap `pidof hush`.
+		 * while if false; then false; fi; do break; fi
+		 * Samples to catch leaks at execution:
+		 * while if (true | { true;}); then echo ok; fi; do break; done
+		 * while if (true | { true;}); then echo ok; fi; do (if echo ok; break; then :; fi) | cat; break; done
+		 */
+		pctx = &ctx;
+		do {
+			/* Update pipe/command counts,
+			 * otherwise freeing may miss some */
+			done_pipe(pctx, PIPE_SEQ);
+			debug_printf_clean("freeing list %p from ctx %p\n",
+					pctx->list_head, pctx);
+			debug_print_tree(pctx->list_head, 0);
+			free_pipe_list(pctx->list_head);
+			debug_printf_clean("freed list %p\n", pctx->list_head);
+#if !BB_MMU
+			o_free(&pctx->as_string);
+#endif
+			IF_HAS_KEYWORDS(p2 = pctx->stack;)
+			if (pctx != &ctx) {
+				free(pctx);
+			}
+			IF_HAS_KEYWORDS(pctx = p2;)
+		} while (HAS_KEYWORDS && pctx);
+
+		o_free(&ctx.word);
+#if !BB_MMU
+		if (pstring)
+			*pstring = NULL;
+#endif
+		debug_leave();
+		return ERR_PTR;
+	}
+}
+
+
+/*** Execution routines ***/
+
+/* Expansion can recurse, need forward decls: */
+#if !BASH_PATTERN_SUBST && !ENABLE_HUSH_CASE
+#define expand_string_to_string(str, EXP_flags, do_unbackslash) \
+	expand_string_to_string(str)
+#endif
+static char *expand_string_to_string(const char *str, int EXP_flags, int do_unbackslash);
+#if ENABLE_HUSH_TICK
+static int process_command_subs(o_string *dest, const char *s);
+#endif
+static int expand_vars_to_list(o_string *output, int n, char *arg);
+
+/* expand_strvec_to_strvec() takes a list of strings, expands
+ * all variable references within and returns a pointer to
+ * a list of expanded strings, possibly with larger number
+ * of strings. (Think VAR="a b"; echo $VAR).
+ * This new list is allocated as a single malloc block.
+ * NULL-terminated list of char* pointers is at the beginning of it,
+ * followed by strings themselves.
+ * Caller can deallocate entire list by single free(list). */
+
+/* A horde of its helpers come first: */
+
+static void o_addblock_duplicate_backslash(o_string *o, const char *str, int len)
+{
+	while (--len >= 0) {
+		char c = *str++;
+
+#if ENABLE_HUSH_BRACE_EXPANSION
+		if (c == '{' || c == '}') {
+			/* { -> \{, } -> \} */
+			o_addchr(o, '\\');
+			/* And now we want to add { or } and continue:
+			 *  o_addchr(o, c);
+			 *  continue;
+			 * luckily, just falling through achieves this.
+			 */
+		}
+#endif
+		o_addchr(o, c);
+		if (c == '\\') {
+			/* \z -> \\\z; \<eol> -> \\<eol> */
+			o_addchr(o, '\\');
+			if (len) {
+				len--;
+				o_addchr(o, '\\');
+				o_addchr(o, *str++);
+			}
+		}
+	}
+}
+
+/* Store given string, finalizing the word and starting new one whenever
+ * we encounter IFS char(s). This is used for expanding variable values.
+ * End-of-string does NOT finalize word: think about 'echo -$VAR-'.
+ * Return in output->ended_in_ifs:
+ * 1 - ended with IFS char, else 0 (this includes case of empty str).
+ */
+static int expand_on_ifs(o_string *output, int n, const char *str)
+{
+	int last_is_ifs = 0;
+
+	while (1) {
+		int word_len;
+
+		if (!*str)  /* EOL - do not finalize word */
+			break;
+		word_len = strcspn(str, G.ifs);
+		if (word_len) {
+			/* We have WORD_LEN leading non-IFS chars */
+			if (!(output->o_expflags & EXP_FLAG_GLOB)) {
+				o_addblock(output, str, word_len);
+			} else {
+				/* Protect backslashes against globbing up :)
+				 * Example: "v='\*'; echo b$v" prints "b\*"
+				 * (and does not try to glob on "*")
+				 */
+				o_addblock_duplicate_backslash(output, str, word_len);
+				/*/ Why can't we do it easier? */
+				/*o_addblock(output, str, word_len); - WRONG: "v='\*'; echo Z$v" prints "Z*" instead of "Z\*" */
+				/*o_addqblock(output, str, word_len); - WRONG: "v='*'; echo Z$v" prints "Z*" instead of Z* files */
+			}
+			last_is_ifs = 0;
+			str += word_len;
+			if (!*str)  /* EOL - do not finalize word */
+				break;
+		}
+
+		/* We know str here points to at least one IFS char */
+		last_is_ifs = 1;
+		str += strspn(str, G.ifs_whitespace); /* skip IFS whitespace chars */
+		if (!*str)  /* EOL - do not finalize word */
+			break;
+
+		if (G.ifs_whitespace != G.ifs /* usually false ($IFS is usually all whitespace), */
+		 && strchr(G.ifs, *str)       /* the second check would fail */
+		) {
+			/* This is a non-whitespace $IFS char */
+			/* Skip it and IFS whitespace chars, start new word */
+			str++;
+			str += strspn(str, G.ifs_whitespace);
+			goto new_word;
+		}
+
+		/* Start new word... but not always! */
+		/* Case "v=' a'; echo ''$v": we do need to finalize empty word: */
+		if (output->has_quoted_part
+		/*
+		 * Case "v=' a'; echo $v":
+		 * here nothing precedes the space in $v expansion,
+		 * therefore we should not finish the word
+		 * (IOW: if there *is* word to finalize, only then do it):
+		 * It's okay if this accesses the byte before first argv[]:
+		 * past call to o_save_ptr() cleared it to zero byte
+		 * (grep for -prev-ifs-check-).
+		 */
+		 || output->data[output->length - 1]
+		) {
+ new_word:
+			o_addchr(output, '\0');
+			debug_print_list("expand_on_ifs", output, n);
+			n = o_save_ptr(output, n);
+		}
+	}
+
+	output->ended_in_ifs = last_is_ifs;
+	debug_print_list("expand_on_ifs[1]", output, n);
+	return n;
+}
+
+/* Helper to expand $((...)) and heredoc body. These act as if
+ * they are in double quotes, with the exception that they are not :).
+ * Just the rules are similar: "expand only $var and `cmd`"
+ *
+ * Returns malloced string.
+ * As an optimization, we return NULL if expansion is not needed.
+ */
+static char *encode_then_expand_string(const char *str)
+{
+	char *exp_str;
+	struct in_str input;
+	o_string dest = NULL_O_STRING;
+	const char *cp;
+
+	cp = str;
+	for (;;) {
+		if (!*cp) return NULL; /* string has no special chars */
+		if (*cp == '$') break;
+		if (*cp == '\\') break;
+#if ENABLE_HUSH_TICK
+		if (*cp == '`') break;
+#endif
+		cp++;
+	}
+
+	/* We need to expand. Example:
+	 * echo $(($a + `echo 1`)) $((1 + $((2)) ))
+	 */
+	setup_string_in_str(&input, str);
+	encode_string(NULL, &dest, &input, EOF);
+//TODO: error check (encode_string returns 0 on error)?
+	//bb_error_msg("'%s' -> '%s'", str, dest.data);
+	exp_str = expand_string_to_string(dest.data,
+			EXP_FLAG_ESC_GLOB_CHARS,
+			/*unbackslash:*/ 1
+	);
+	//bb_error_msg("'%s' -> '%s'", dest.data, exp_str);
+	o_free(&dest);
+	return exp_str;
+}
+
+static const char *first_special_char_in_vararg(const char *cp)
+{
+	for (;;) {
+		if (!*cp) return NULL; /* string has no special chars */
+		if (*cp == '$') return cp;
+		if (*cp == '\\') return cp;
+		if (*cp == '\'') return cp;
+		if (*cp == '"') return cp;
+#if ENABLE_HUSH_TICK
+		if (*cp == '`') return cp;
+#endif
+		/* dquoted "${x:+ARG}" should not glob, therefore
+		 * '*' et al require some non-literal processing: */
+		if (*cp == '*') return cp;
+		if (*cp == '?') return cp;
+		if (*cp == '[') return cp;
+		cp++;
+	}
+}
+
+/* Expanding ARG in ${var#ARG}, ${var%ARG}, or ${var/ARG/ARG}.
+ * These can contain single- and double-quoted strings,
+ * and treated as if the ARG string is initially unquoted. IOW:
+ * ${var#ARG} and "${var#ARG}" treat ARG the same (ARG can even be
+ * a dquoted string: "${var#"zz"}"), the difference only comes later
+ * (word splitting and globbing of the ${var...} result).
+ */
+#if !BASH_PATTERN_SUBST
+#define encode_then_expand_vararg(str, handle_squotes, do_unbackslash) \
+	encode_then_expand_vararg(str, handle_squotes)
+#endif
+static char *encode_then_expand_vararg(const char *str, int handle_squotes, int do_unbackslash)
+{
+#if !BASH_PATTERN_SUBST && ENABLE_HUSH_CASE
+	const int do_unbackslash = 0;
+#endif
+	char *exp_str;
+	struct in_str input;
+	o_string dest = NULL_O_STRING;
+
+	if (!first_special_char_in_vararg(str)) {
+		/* string has no special chars */
+		return NULL;
+	}
+
+	setup_string_in_str(&input, str);
+	dest.data = xzalloc(1); /* start as "", not as NULL */
+	exp_str = NULL;
+
+	for (;;) {
+		int ch;
+
+		ch = i_getch(&input);
+		debug_printf_parse("%s: ch=%c (%d) escape=%d\n",
+				__func__, ch, ch, !!dest.o_expflags);
+
+		if (!dest.o_expflags) {
+			if (ch == EOF)
+				break;
+			if (handle_squotes && ch == '\'') {
+				if (!add_till_single_quote_dquoted(&dest, &input))
+					goto ret; /* error */
+				continue;
+			}
+		}
+		if (ch == EOF) {
+			syntax_error_unterm_ch('"');
+			goto ret; /* error */
+		}
+		if (ch == '"') {
+			dest.o_expflags ^= EXP_FLAG_ESC_GLOB_CHARS;
+			continue;
+		}
+		if (ch == '\\') {
+			ch = i_getch(&input);
+			if (ch == EOF) {
+//example? error message?	syntax_error_unterm_ch('"');
+				debug_printf_parse("%s: error: \\<eof>\n", __func__);
+				goto ret;
+			}
+			o_addqchr(&dest, ch);
+			continue;
+		}
+		if (ch == '$') {
+			if (parse_dollar_squote(NULL, &dest, &input))
+				continue;
+			if (!parse_dollar(NULL, &dest, &input, /*quote_mask:*/ 0x80)) {
+				debug_printf_parse("%s: error: parse_dollar returned 0 (error)\n", __func__);
+				goto ret;
+			}
+			continue;
+		}
+#if ENABLE_HUSH_TICK
+		if (ch == '`') {
+			//unsigned pos = dest->length;
+			o_addchr(&dest, SPECIAL_VAR_SYMBOL);
+			o_addchr(&dest, 0x80 | '`');
+			if (!add_till_backquote(&dest, &input,
+					/*in_dquote:*/ dest.o_expflags /* nonzero if EXP_FLAG_ESC_GLOB_CHARS set */
+				)
+			) {
+				goto ret; /* error */
+			}
+			o_addchr(&dest, SPECIAL_VAR_SYMBOL);
+			//debug_printf_subst("SUBST RES3 '%s'\n", dest->data + pos);
+			continue;
+		}
+#endif
+		o_addQchr(&dest, ch);
+	} /* for (;;) */
+
+	debug_printf_parse("encode: '%s' -> '%s'\n", str, dest.data);
+	exp_str = expand_string_to_string(dest.data,
+			do_unbackslash ? EXP_FLAG_ESC_GLOB_CHARS : 0,
+			do_unbackslash
+	);
+ ret:
+	debug_printf_parse("expand: '%s' -> '%s'\n", dest.data, exp_str);
+	o_free(&dest);
+	return exp_str;
+}
+
+/* Expanding ARG in ${var+ARG}, ${var-ARG}
+ */
+static int encode_then_append_var_plusminus(o_string *output, int n,
+		char *str, int dquoted)
+{
+	struct in_str input;
+	o_string dest = NULL_O_STRING;
+
+	if (!first_special_char_in_vararg(str)
+	 && '\0' == str[strcspn(str, G.ifs)]
+	) {
+		/* string has no special chars
+		 * && string has no $IFS chars
+		 */
+		if (dquoted) {
+			/* Prints 1 (quoted expansion is a "" word, not nothing):
+			 * set -- "${notexist-}"; echo $#
+			 */
+			output->has_quoted_part = 1;
+		}
+		return expand_vars_to_list(output, n, str);
+	}
+
+	setup_string_in_str(&input, str);
+
+	for (;;) {
+		int ch;
+
+		ch = i_getch(&input);
+		debug_printf_parse("%s: ch=%c (%d) escape=%x\n",
+				__func__, ch, ch, dest.o_expflags);
+
+		if (!dest.o_expflags) {
+			if (ch == EOF)
+				break;
+			if (!dquoted && strchr(G.ifs, ch)) {
+				/* PREFIX${x:d${e}f ...} and we met space: expand "d${e}f" and start new word.
+				 * do not assume we are at the start of the word (PREFIX above).
+				 */
+				if (dest.data) {
+					n = expand_vars_to_list(output, n, dest.data);
+					o_free_and_set_NULL(&dest);
+					o_addchr(output, '\0');
+					n = o_save_ptr(output, n); /* create next word */
+				} else
+				if (output->length != o_get_last_ptr(output, n)
+				 || output->has_quoted_part
+				) {
+					/* For these cases:
+					 * f() { for i; do echo "|$i|"; done; }; x=x
+					 * f a${x:+ }b  # 1st condition
+					 * |a|
+					 * |b|
+					 * f ""${x:+ }b  # 2nd condition
+					 * ||
+					 * |b|
+					 */
+					o_addchr(output, '\0');
+					n = o_save_ptr(output, n); /* create next word */
+				}
+				continue;
+			}
+			if (!dquoted && ch == '\'') {
+				if (!add_till_single_quote_dquoted(&dest, &input))
+					goto ret; /* error */
+				o_addchr(&dest, SPECIAL_VAR_SYMBOL);
+				o_addchr(&dest, SPECIAL_VAR_SYMBOL);
+				continue;
+			}
+		}
+		if (ch == EOF) {
+			syntax_error_unterm_ch('"');
+			goto ret; /* error */
+		}
+		if (ch == '"') {
+			dest.o_expflags ^= EXP_FLAG_ESC_GLOB_CHARS;
+			if (dest.o_expflags) {
+				o_addchr(&dest, SPECIAL_VAR_SYMBOL);
+				o_addchr(&dest, SPECIAL_VAR_SYMBOL);
+			}
+			continue;
+		}
+		if (ch == '\\') {
+			ch = i_getch(&input);
+			if (ch == EOF) {
+//example? error message?	syntax_error_unterm_ch('"');
+				debug_printf_parse("%s: error: \\<eof>\n", __func__);
+				goto ret;
+			}
+			o_addqchr(&dest, ch);
+			continue;
+		}
+		if (ch == '$') {
+			if (!parse_dollar(NULL, &dest, &input, /*quote_mask:*/ (dest.o_expflags || dquoted) ? 0x80 : 0)) {
+				debug_printf_parse("%s: error: parse_dollar returned 0 (error)\n", __func__);
+				goto ret;
+			}
+			continue;
+		}
+#if ENABLE_HUSH_TICK
+		if (ch == '`') {
+			//unsigned pos = dest->length;
+			o_addchr(&dest, SPECIAL_VAR_SYMBOL);
+			o_addchr(&dest, (dest.o_expflags || dquoted) ? 0x80 | '`' : '`');
+			if (!add_till_backquote(&dest, &input,
+					/*in_dquote:*/ dest.o_expflags /* nonzero if EXP_FLAG_ESC_GLOB_CHARS set */
+				)
+			) {
+				goto ret; /* error */
+			}
+			o_addchr(&dest, SPECIAL_VAR_SYMBOL);
+			//debug_printf_subst("SUBST RES3 '%s'\n", dest->data + pos);
+			continue;
+		}
+#endif
+		if (dquoted) {
+			/* Always glob-protect if in dquotes:
+			 * x=x; echo "${x:+/bin/c*}" - prints: /bin/c*
+			 * x=x; echo "${x:+"/bin/c*"}" - prints: /bin/c*
+			 */
+			o_addqchr(&dest, ch);
+		} else {
+			/* Glob-protect only if char is quoted:
+			 * x=x; echo ${x:+/bin/c*} - prints many filenames
+			 * x=x; echo ${x:+"/bin/c*"} - prints: /bin/c*
+			 */
+			o_addQchr(&dest, ch);
+		}
+	} /* for (;;) */
+
+	if (dest.data) {
+		n = expand_vars_to_list(output, n, dest.data);
+	}
+ ret:
+	o_free(&dest);
+	return n;
+}
+
+#if ENABLE_FEATURE_SH_MATH
+static arith_t expand_and_evaluate_arith(const char *arg, const char **errmsg_p)
+{
+	arith_state_t math_state;
+	arith_t res;
+	char *exp_str;
+
+	math_state.lookupvar = get_local_var_value;
+	math_state.setvar = set_local_var_from_halves;
+	//math_state.endofname = endofname;
+	exp_str = encode_then_expand_string(arg);
+	res = arith(&math_state, exp_str ? exp_str : arg);
+	free(exp_str);
+	if (errmsg_p)
+		*errmsg_p = math_state.errmsg;
+	if (math_state.errmsg)
+		msg_and_die_if_script(math_state.errmsg);
+	return res;
+}
+#endif
+
+#if BASH_PATTERN_SUBST
+/* ${var/[/]pattern[/repl]} helpers */
+static char *strstr_pattern(char *val, const char *pattern, int *size)
+{
+	int sz = strcspn(pattern, "*?[\\");
+	if (pattern[sz] == '\0') {
+		/* Optimization for trivial patterns.
+		 * Testcase for very slow replace (performs about 22k replaces):
+		 * x=::::::::::::::::::::::
+		 * x=$x$x;x=$x$x;x=$x$x;x=$x$x;x=$x$x;x=$x$x;x=$x$x;x=$x$x;x=$x$x;x=$x$x;echo ${#x}
+		 * echo "${x//:/|}"
+		 */
+		*size = sz;
+		return strstr(val, pattern);
+	}
+
+	while (1) {
+		char *end = scan_and_match(val, pattern, SCAN_MOVE_FROM_RIGHT + SCAN_MATCH_LEFT_HALF);
+		debug_printf_varexp("val:'%s' pattern:'%s' end:'%s'\n", val, pattern, end);
+		if (end) {
+			*size = end - val;
+			return val;
+		}
+		if (*val == '\0')
+			return NULL;
+		/* Optimization: if "*pat" did not match the start of "string",
+		 * we know that "tring", "ring" etc will not match too:
+		 */
+		if (pattern[0] == '*')
+			return NULL;
+		val++;
+	}
+}
+static char *replace_pattern(char *val, const char *pattern, const char *repl, char exp_op)
+{
+	char *result = NULL;
+	unsigned res_len = 0;
+	unsigned repl_len = strlen(repl);
+
+	/* Null pattern never matches, including if "var" is empty */
+	if (!pattern[0])
+		return result; /* NULL, no replaces happened */
+
+	while (1) {
+		int size;
+		char *s = strstr_pattern(val, pattern, &size);
+		if (!s)
+			break;
+
+		result = xrealloc(result, res_len + (s - val) + repl_len + 1);
+		strcpy(mempcpy(result + res_len, val, s - val), repl);
+		res_len += (s - val) + repl_len;
+		debug_printf_varexp("val:'%s' s:'%s' result:'%s'\n", val, s, result);
+
+		val = s + size;
+		if (exp_op == '/')
+			break;
+	}
+	if (*val && result) {
+		result = xrealloc(result, res_len + strlen(val) + 1);
+		strcpy(result + res_len, val);
+		debug_printf_varexp("val:'%s' result:'%s'\n", val, result);
+	}
+	debug_printf_varexp("result:'%s'\n", result);
+	return result;
+}
+#endif /* BASH_PATTERN_SUBST */
+
+static int append_str_maybe_ifs_split(o_string *output, int n,
+		int first_ch, const char *val)
+{
+	if (!(first_ch & 0x80)) { /* unquoted $VAR */
+		debug_printf_expand("unquoted '%s', output->o_escape:%d\n", val,
+				!!(output->o_expflags & EXP_FLAG_ESC_GLOB_CHARS));
+		if (val && val[0])
+			n = expand_on_ifs(output, n, val);
+	} else { /* quoted "$VAR" */
+		output->has_quoted_part = 1;
+		debug_printf_expand("quoted '%s', output->o_escape:%d\n", val,
+				!!(output->o_expflags & EXP_FLAG_ESC_GLOB_CHARS));
+		if (val && val[0])
+			o_addQstr(output, val);
+	}
+	return n;
+}
+
+/* Handle <SPECIAL_VAR_SYMBOL>varname...<SPECIAL_VAR_SYMBOL> construct.
+ */
+static NOINLINE int expand_one_var(o_string *output, int n,
+		int first_ch, char *arg, char **pp)
+{
+	const char *val;
+	char *to_be_freed;
+	char *p;
+	char *var;
+	char exp_op;
+	char exp_save = exp_save; /* for compiler */
+	char *exp_saveptr; /* points to expansion operator */
+	char *exp_word = exp_word; /* for compiler */
+	char arg0;
+
+	val = NULL;
+	to_be_freed = NULL;
+	p = *pp;
+	*p = '\0'; /* replace trailing SPECIAL_VAR_SYMBOL */
+	var = arg;
+	exp_saveptr = arg[1] ? strchr(VAR_ENCODED_SUBST_OPS, arg[1]) : NULL;
+	arg0 = arg[0];
+	arg[0] = (arg0 & 0x7f);
+	exp_op = 0;
+
+	if (arg[0] == '#' && arg[1] /* ${#...} but not ${#} */
+	 && (!exp_saveptr               /* and ( not(${#<op_char>...}) */
+	    || (arg[2] == '\0' && strchr(SPECIAL_VARS_STR, arg[1])) /* or ${#C} "len of $C" ) */
+	    )		/* NB: skipping ^^^specvar check mishandles ${#::2} */
+	) {
+		/* It must be length operator: ${#var} */
+		var++;
+		exp_op = 'L';
+	} else {
+		/* Maybe handle parameter expansion */
+		if (exp_saveptr /* if 2nd char is one of expansion operators */
+		 && strchr(NUMERIC_SPECVARS_STR, arg[0]) /* 1st char is special variable */
+		) {
+			/* ${?:0}, ${#[:]%0} etc */
+			exp_saveptr = var + 1;
+		} else {
+			/* ${?}, ${var}, ${var:0}, ${var[:]%0} etc */
+			exp_saveptr = var+1 + strcspn(var+1, VAR_ENCODED_SUBST_OPS);
+		}
+		exp_op = exp_save = *exp_saveptr;
+		if (exp_op) {
+			exp_word = exp_saveptr + 1;
+			if (exp_op == ':') {
+				exp_op = *exp_word++;
+//TODO: try ${var:} and ${var:bogus} in non-bash config
+				if (BASH_SUBSTR
+				 && (!exp_op || !strchr(MINUS_PLUS_EQUAL_QUESTION, exp_op))
+				) {
+					/* oops... it's ${var:N[:M]}, not ${var:?xxx} or some such */
+					exp_op = ':';
+					exp_word--;
+				}
+			}
+			*exp_saveptr = '\0';
+		} /* else: it's not an expansion op, but bare ${var} */
+	}
+
+	/* Look up the variable in question */
+	if (isdigit(var[0])) {
+		/* parse_dollar should have vetted var for us */
+		int nn = xatoi_positive(var);
+		if (nn < G.global_argc)
+			val = G.global_argv[nn];
+		/* else val remains NULL: $N with too big N */
+	} else {
+		switch (var[0]) {
+		case '$': /* pid */
+			val = utoa(G.root_pid);
+			break;
+		case '!': /* bg pid */
+			val = G.last_bg_pid ? utoa(G.last_bg_pid) : "";
+			break;
+		case '?': /* exitcode */
+			val = utoa(G.last_exitcode);
+			break;
+		case '#': /* argc */
+			val = utoa(G.global_argc ? G.global_argc-1 : 0);
+			break;
+		case '-': { /* active options */
+			/* Check set_mode() to see what option chars we support */
+			char *cp;
+			val = cp = G.optstring_buf;
+			if (G.o_opt[OPT_O_ERREXIT])
+				*cp++ = 'e';
+			if (G_interactive_fd)
+				*cp++ = 'i';
+			if (G_x_mode)
+				*cp++ = 'x';
+			/* If G.o_opt[OPT_O_NOEXEC] is true,
+			 * commands read but are not executed,
+			 * so $- can not execute too, 'n' is never seen in $-.
+			 */
+			if (G.opt_c)
+				*cp++ = 'c';
+			if (G.opt_s)
+				*cp++ = 's';
+			*cp = '\0';
+			break;
+		}
+		default:
+			val = get_local_var_value(var);
+		}
+	}
+
+	/* Handle any expansions */
+	if (exp_op == 'L') {
+		reinit_unicode_for_hush();
+		debug_printf_expand("expand: length(%s)=", val);
+		val = utoa(val ? unicode_strlen(val) : 0);
+		debug_printf_expand("%s\n", val);
+	} else if (exp_op) {
+		if (exp_op == '%' || exp_op == '#') {
+			/* Standard-mandated substring removal ops:
+			 * ${parameter%word} - remove smallest suffix pattern
+			 * ${parameter%%word} - remove largest suffix pattern
+			 * ${parameter#word} - remove smallest prefix pattern
+			 * ${parameter##word} - remove largest prefix pattern
+			 *
+			 * Word is expanded to produce a glob pattern.
+			 * Then var's value is matched to it and matching part removed.
+			 */
+			/* bash compat: if x is "" and no shrinking of it is possible,
+			 * inner ${...} is not evaluated. Example:
+			 *  unset b; : ${a%${b=B}}; echo $b
+			 * assignment b=B only happens if $a is not "".
+			 */
+			if (val && val[0]) {
+				char *t;
+				char *exp_exp_word;
+				char *loc;
+				unsigned scan_flags = pick_scan(exp_op, *exp_word);
+				if (exp_op == *exp_word)  /* ## or %% */
+					exp_word++;
+				debug_printf_expand("expand: exp_word:'%s'\n", exp_word);
+				exp_exp_word = encode_then_expand_vararg(exp_word, /*handle_squotes:*/ 1, /*unbackslash:*/ 0);
+				if (exp_exp_word)
+					exp_word = exp_exp_word;
+				debug_printf_expand("expand: exp_word:'%s'\n", exp_word);
+				/*
+				 * HACK ALERT. We depend here on the fact that
+				 * G.global_argv and results of utoa and get_local_var_value
+				 * are actually in writable memory:
+				 * scan_and_match momentarily stores NULs there.
+				 */
+				t = (char*)val;
+				loc = scan_and_match(t, exp_word, scan_flags);
+				debug_printf_expand("op:%c str:'%s' pat:'%s' res:'%s'\n", exp_op, t, exp_word, loc);
+				free(exp_exp_word);
+				if (loc) { /* match was found */
+					if (scan_flags & SCAN_MATCH_LEFT_HALF) /* #[#] */
+						val = loc; /* take right part */
+					else /* %[%] */
+						val = to_be_freed = xstrndup(val, loc - val); /* left */
+				}
+			}
+		}
+#if BASH_PATTERN_SUBST
+		else if (exp_op == '/' || exp_op == '\\') {
+			/* It's ${var/[/]pattern[/repl]} thing.
+			 * Note that in encoded form it has TWO parts:
+			 * var/pattern<SPECIAL_VAR_SYMBOL>repl<SPECIAL_VAR_SYMBOL>
+			 * and if // is used, it is encoded as \:
+			 * var\pattern<SPECIAL_VAR_SYMBOL>repl<SPECIAL_VAR_SYMBOL>
+			 */
+			/* bash compat: if var is "", both pattern and repl
+			 * are still evaluated, if it is unset, then not:
+			 * unset b; a=; : ${a/z/${b=3}}; echo $b      # b=3
+			 * unset b; unset a; : ${a/z/${b=3}}; echo $b # b not set
+			 */
+			if (val /*&& val[0]*/) {
+				/* pattern uses non-standard expansion.
+				 * repl should be unbackslashed and globbed
+				 * by the usual expansion rules:
+				 *  >az >bz
+				 *  v='a bz'; echo "${v/a*z/a*z}" #prints "a*z"
+				 *  v='a bz'; echo "${v/a*z/\z}"  #prints "z"
+				 *  v='a bz'; echo ${v/a*z/a*z}   #prints "az"
+				 *  v='a bz'; echo ${v/a*z/\z}    #prints "z"
+				 * (note that a*z _pattern_ is never globbed!)
+				 */
+				char *pattern, *repl, *t;
+				pattern = encode_then_expand_vararg(exp_word, /*handle_squotes:*/ 1, /*unbackslash:*/ 0);
+				if (!pattern)
+					pattern = xstrdup(exp_word);
+				debug_printf_varexp("pattern:'%s'->'%s'\n", exp_word, pattern);
+				*p++ = SPECIAL_VAR_SYMBOL;
+				exp_word = p;
+				p = strchr(p, SPECIAL_VAR_SYMBOL);
+				*p = '\0';
+				repl = encode_then_expand_vararg(exp_word, /*handle_squotes:*/ 1, /*unbackslash:*/ 1);
+				debug_printf_varexp("repl:'%s'->'%s'\n", exp_word, repl);
+				/* HACK ALERT. We depend here on the fact that
+				 * G.global_argv and results of utoa and get_local_var_value
+				 * are actually in writable memory:
+				 * replace_pattern momentarily stores NULs there. */
+				t = (char*)val;
+				to_be_freed = replace_pattern(t,
+						pattern,
+						(repl ? repl : exp_word),
+						exp_op);
+				if (to_be_freed) /* at least one replace happened */
+					val = to_be_freed;
+				free(pattern);
+				free(repl);
+			} else {
+				/* Unset variable always gives nothing */
+				//  a=; echo ${a/*/w}      # "w"
+				//  unset a; echo ${a/*/w} # ""
+				/* Just skip "replace" part */
+				*p++ = SPECIAL_VAR_SYMBOL;
+				p = strchr(p, SPECIAL_VAR_SYMBOL);
+				*p = '\0';
+			}
+		}
+#endif /* BASH_PATTERN_SUBST */
+		else if (exp_op == ':') {
+#if BASH_SUBSTR && ENABLE_FEATURE_SH_MATH
+			/* It's ${var:N[:M]} bashism.
+			 * Note that in encoded form it has TWO parts:
+			 * var:N<SPECIAL_VAR_SYMBOL>M<SPECIAL_VAR_SYMBOL>
+			 */
+			arith_t beg, len;
+			unsigned vallen;
+			const char *errmsg;
+
+			beg = expand_and_evaluate_arith(exp_word, &errmsg);
+			if (errmsg)
+				goto empty_result;
+			debug_printf_varexp("beg:'%s'=%lld\n", exp_word, (long long)beg);
+			*p++ = SPECIAL_VAR_SYMBOL;
+			exp_word = p;
+			p = strchr(p, SPECIAL_VAR_SYMBOL);
+			*p = '\0';
+			vallen = val ? strlen(val) : 0;
+			if (beg < 0) {
+				/* negative beg counts from the end */
+				beg = (arith_t)vallen + beg;
+			}
+			/* If expansion will be empty, do not even evaluate len */
+			if (!val || beg < 0 || beg > vallen) {
+				/* Why > vallen, not >=? bash:
+				 * unset b; a=ab; : ${a:2:${b=3}}; echo $b  # "", b=3 (!!!)
+				 * unset b; a=a; : ${a:2:${b=3}}; echo $b   # "", b not set
+				 */
+				goto empty_result;
+			}
+			len = expand_and_evaluate_arith(exp_word, &errmsg);
+			if (errmsg)
+				goto empty_result;
+			debug_printf_varexp("len:'%s'=%lld\n", exp_word, (long long)len);
+			debug_printf_varexp("from val:'%s'\n", val);
+			if (len < 0) {
+				/* in bash, len=-n means strlen()-n */
+				len = (arith_t)vallen - beg + len;
+				if (len < 0) /* bash compat */
+					msg_and_die_if_script("%s: substring expression < 0", var);
+			}
+			if (len <= 0 || !val /*|| beg >= vallen*/) {
+ empty_result:
+				val = NULL;
+			} else {
+				/* Paranoia. What if user entered 9999999999999
+				 * which fits in arith_t but not int? */
+				if (len > INT_MAX)
+					len = INT_MAX;
+				val = to_be_freed = xstrndup(val + beg, len);
+			}
+			debug_printf_varexp("val:'%s'\n", val);
+#else /* not (HUSH_SUBSTR_EXPANSION && FEATURE_SH_MATH) */
+			msg_and_die_if_script("malformed ${%s:...}", var);
+			val = NULL;
+#endif
+		} else { /* one of "-=+?" */
+			/* Standard-mandated substitution ops:
+			 * ${var?word} - indicate error if unset
+			 *      If var is unset, word (or a message indicating it is unset
+			 *      if word is null) is written to standard error
+			 *      and the shell exits with a non-zero exit status.
+			 *      Otherwise, the value of var is substituted.
+			 * ${var-word} - use default value
+			 *      If var is unset, word is substituted.
+			 * ${var=word} - assign and use default value
+			 *      If var is unset, word is assigned to var.
+			 *      In all cases, final value of var is substituted.
+			 * ${var+word} - use alternative value
+			 *      If var is unset, null is substituted.
+			 *      Otherwise, word is substituted.
+			 *
+			 * Word is subjected to tilde expansion, parameter expansion,
+			 * command substitution, and arithmetic expansion.
+			 * If word is not needed, it is not expanded.
+			 *
+			 * Colon forms (${var:-word}, ${var:=word} etc) do the same,
+			 * but also treat null var as if it is unset.
+			 *
+			 * Word-splitting and single quote behavior:
+			 *
+			 * $ f() { for i; do echo "|$i|"; done; }
+			 *
+			 * $ x=; f ${x:?'x y' z}; echo $?
+			 * bash: x: x y z       # neither f nor "echo $?" executes
+			 * (if interactive, bash does not exit, but merely aborts to prompt. $? is set to 1)
+			 * $ x=; f "${x:?'x y' z}"
+			 * bash: x: x y z       # dash prints: dash: x: 'x y' z
+			 *
+			 * $ x=; f ${x:='x y' z}
+			 * |x|
+			 * |y|
+			 * |z|
+			 * $ x=; f "${x:='x y' z}"
+			 * |'x y' z|
+			 *
+			 * $ x=x; f ${x:+'x y' z}
+			 * |x y|
+			 * |z|
+			 * $ x=x; f "${x:+'x y' z}"
+			 * |'x y' z|
+			 *
+			 * $ x=; f ${x:-'x y' z}
+			 * |x y|
+			 * |z|
+			 * $ x=; f "${x:-'x y' z}"
+			 * |'x y' z|
+			 */
+			int use_word = (!val || ((exp_save == ':') && !val[0]));
+			if (exp_op == '+')
+				use_word = !use_word;
+			debug_printf_expand("expand: op:%c (null:%s) test:%i\n", exp_op,
+					(exp_save == ':') ? "true" : "false", use_word);
+			if (use_word) {
+				if (exp_op == '+' || exp_op == '-') {
+					/* ${var+word} - use alternative value */
+					/* ${var-word} - use default value */
+					n = encode_then_append_var_plusminus(output, n, exp_word,
+							/*dquoted:*/ (arg0 & 0x80)
+					);
+					val = NULL;
+				} else {
+					/* ${var?word} - indicate error if unset */
+					/* ${var=word} - assign and use default value */
+					to_be_freed = encode_then_expand_vararg(exp_word,
+							/*handle_squotes:*/ !(arg0 & 0x80),
+							/*unbackslash:*/ 0
+					);
+					if (to_be_freed)
+						exp_word = to_be_freed;
+					if (exp_op == '?') {
+						/* mimic bash message */
+						msg_and_die_if_script("%s: %s",
+							var,
+							exp_word[0]
+							? exp_word
+							: "parameter null or not set"
+							/* ash has more specific messages, a-la: */
+							/*: (exp_save == ':' ? "parameter null or not set" : "parameter not set")*/
+						);
+//TODO: how interactive bash aborts expansion mid-command?
+//It aborts the entire line, returns to prompt:
+// $ f() { for i; do echo "|$i|"; done; }; x=; f "${x:?'x y' z}"; echo YO
+// bash: x: x y z
+// $
+// ("echo YO" is not executed, neither the f function call)
+					} else {
+						val = exp_word;
+					}
+					if (exp_op == '=') {
+						/* ${var=[word]} or ${var:=[word]} */
+						if (isdigit(var[0]) || var[0] == '#') {
+							/* mimic bash message */
+							msg_and_die_if_script("$%s: cannot assign in this way", var);
+							val = NULL;
+						} else {
+							char *new_var = xasprintf("%s=%s", var, val);
+							set_local_var(new_var, /*flag:*/ 0);
+						}
+					}
+				}
+			}
+		} /* one of "-=+?" */
+
+		*exp_saveptr = exp_save;
+	} /* if (exp_op) */
+
+	arg[0] = arg0;
+	*pp = p;
+
+	n = append_str_maybe_ifs_split(output, n, first_ch, val);
+
+	free(to_be_freed);
+	return n;
+}
+
+/* Expand all variable references in given string, adding words to list[]
+ * at n, n+1,... positions. Return updated n (so that list[n] is next one
+ * to be filled). This routine is extremely tricky: has to deal with
+ * variables/parameters with whitespace, $* and $@, and constructs like
+ * 'echo -$*-'. If you play here, you must run testsuite afterwards! */
+static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg)
+{
+	/* output->o_expflags & EXP_FLAG_SINGLEWORD (0x80) if we are in
+	 * expansion of right-hand side of assignment == 1-element expand.
+	 */
+	char cant_be_null = 0; /* only bit 0x80 matters */
+	char *p;
+
+	debug_printf_expand("expand_vars_to_list: arg:'%s' singleword:%x\n", arg,
+			!!(output->o_expflags & EXP_FLAG_SINGLEWORD));
+	debug_print_list("expand_vars_to_list[0]", output, n);
+
+	while ((p = strchr(arg, SPECIAL_VAR_SYMBOL)) != NULL) {
+		char first_ch;
+#if ENABLE_FEATURE_SH_MATH
+		char arith_buf[sizeof(arith_t)*3 + 2];
+#endif
+
+		if (output->ended_in_ifs) {
+			o_addchr(output, '\0');
+			n = o_save_ptr(output, n);
+			output->ended_in_ifs = 0;
+		}
+
+		o_addblock(output, arg, p - arg);
+		debug_print_list("expand_vars_to_list[1]", output, n);
+		arg = ++p;
+		p = strchr(p, SPECIAL_VAR_SYMBOL);
+
+		/* Fetch special var name (if it is indeed one of them)
+		 * and quote bit, force the bit on if singleword expansion -
+		 * important for not getting v=$@ expand to many words. */
+		first_ch = arg[0] | (output->o_expflags & EXP_FLAG_SINGLEWORD);
+
+		/* Is this variable quoted and thus expansion can't be null?
+		 * "$@" is special. Even if quoted, it can still
+		 * expand to nothing (not even an empty string),
+		 * thus it is excluded. */
+		if ((first_ch & 0x7f) != '@')
+			cant_be_null |= first_ch;
+
+		switch (first_ch & 0x7f) {
+		/* Highest bit in first_ch indicates that var is double-quoted */
+		case '*':
+		case '@': {
+			int i;
+			if (!G.global_argv[1])
+				break;
+			i = 1;
+			cant_be_null |= first_ch; /* do it for "$@" _now_, when we know it's not empty */
+			if (!(first_ch & 0x80)) { /* unquoted $* or $@ */
+				while (G.global_argv[i]) {
+					n = expand_on_ifs(output, n, G.global_argv[i]);
+					debug_printf_expand("expand_vars_to_list: argv %d (last %d)\n", i, G.global_argc - 1);
+					if (G.global_argv[i++][0] && G.global_argv[i]) {
+						/* this argv[] is not empty and not last:
+						 * put terminating NUL, start new word */
+						o_addchr(output, '\0');
+						debug_print_list("expand_vars_to_list[2]", output, n);
+						n = o_save_ptr(output, n);
+						debug_print_list("expand_vars_to_list[3]", output, n);
+					}
+				}
+			} else
+			/* If EXP_FLAG_SINGLEWORD, we handle assignment 'a=....$@.....'
+			 * and in this case should treat it like '$*' - see 'else...' below */
+			if (first_ch == (char)('@'|0x80)  /* quoted $@ */
+			 && !(output->o_expflags & EXP_FLAG_SINGLEWORD) /* not v="$@" case */
+			) {
+				while (1) {
+					o_addQstr(output, G.global_argv[i]);
+					if (++i >= G.global_argc)
+						break;
+					o_addchr(output, '\0');
+					debug_print_list("expand_vars_to_list[4]", output, n);
+					n = o_save_ptr(output, n);
+				}
+			} else { /* quoted $* (or v="$@" case): add as one word */
+				while (1) {
+					o_addQstr(output, G.global_argv[i]);
+					if (!G.global_argv[++i])
+						break;
+					if (G.ifs[0])
+						o_addchr(output, G.ifs[0]);
+				}
+				output->has_quoted_part = 1;
+			}
+			break;
+		}
+		case SPECIAL_VAR_SYMBOL: {
+			/* <SPECIAL_VAR_SYMBOL><SPECIAL_VAR_SYMBOL> */
+			/* "Empty variable", used to make "" etc to not disappear */
+			output->has_quoted_part = 1;
+			cant_be_null = 0x80;
+			arg++;
+			break;
+		}
+		case SPECIAL_VAR_QUOTED_SVS:
+			/* <SPECIAL_VAR_SYMBOL><SPECIAL_VAR_QUOTED_SVS><SPECIAL_VAR_SYMBOL> */
+			/* "^C variable", represents literal ^C char (possible in scripts) */
+			o_addchr(output, SPECIAL_VAR_SYMBOL);
+			arg++;
+			break;
+#if ENABLE_HUSH_TICK
+		case '`': {
+			/* <SPECIAL_VAR_SYMBOL>`cmd<SPECIAL_VAR_SYMBOL> */
+			o_string subst_result = NULL_O_STRING;
+
+			*p = '\0'; /* replace trailing <SPECIAL_VAR_SYMBOL> */
+			arg++;
+			/* Can't just stuff it into output o_string,
+			 * expanded result may need to be globbed
+			 * and $IFS-split */
+			debug_printf_subst("SUBST '%s' first_ch %x\n", arg, first_ch);
+			G.last_exitcode = process_command_subs(&subst_result, arg);
+			G.expand_exitcode = G.last_exitcode;
+			debug_printf_subst("SUBST RES:%d '%s'\n", G.last_exitcode, subst_result.data);
+			n = append_str_maybe_ifs_split(output, n, first_ch, subst_result.data);
+			o_free(&subst_result);
+			break;
+		}
+#endif
+#if ENABLE_FEATURE_SH_MATH
+		case '+': {
+			/* <SPECIAL_VAR_SYMBOL>+arith<SPECIAL_VAR_SYMBOL> */
+			arith_t res;
+
+			arg++; /* skip '+' */
+			*p = '\0'; /* replace trailing <SPECIAL_VAR_SYMBOL> */
+			debug_printf_subst("ARITH '%s' first_ch %x\n", arg, first_ch);
+			res = expand_and_evaluate_arith(arg, NULL);
+			debug_printf_subst("ARITH RES '"ARITH_FMT"'\n", res);
+			sprintf(arith_buf, ARITH_FMT, res);
+			if (res < 0
+			 && first_ch == (char)('+'|0x80)
+			/* && (output->o_expflags & EXP_FLAG_ESC_GLOB_CHARS) */
+			) {
+				/* Quoted negative ariths, like filename[0"$((-9))"],
+				 * should not be interpreted as glob ranges.
+				 * Convert leading '-' to '\-':
+				 */
+				o_grow_by(output, 1);
+				output->data[output->length++] = '\\';
+			}
+			o_addstr(output, arith_buf);
+			break;
+		}
+#endif
+		default:
+			/* <SPECIAL_VAR_SYMBOL>varname[ops]<SPECIAL_VAR_SYMBOL> */
+			n = expand_one_var(output, n, first_ch, arg, &p);
+			break;
+		} /* switch (char after <SPECIAL_VAR_SYMBOL>) */
+
+		/* Restore NULL'ed SPECIAL_VAR_SYMBOL.
+		 * Do the check to avoid writing to a const string. */
+		if (*p != SPECIAL_VAR_SYMBOL)
+			*p = SPECIAL_VAR_SYMBOL;
+		arg = ++p;
+	} /* end of "while (SPECIAL_VAR_SYMBOL is found) ..." */
+
+	if (*arg) {
+		/* handle trailing string */
+		if (output->ended_in_ifs) {
+			o_addchr(output, '\0');
+			n = o_save_ptr(output, n);
+		}
+		debug_print_list("expand_vars_to_list[a]", output, n);
+		/* this part is literal, and it was already pre-quoted
+		 * if needed (much earlier), do not use o_addQstr here!
+		 */
+		o_addstr(output, arg);
+		debug_print_list("expand_vars_to_list[b]", output, n);
+	} else
+	if (output->length == o_get_last_ptr(output, n) /* expansion is empty */
+	 && !(cant_be_null & 0x80)   /* and all vars were not quoted */
+	 && !output->has_quoted_part
+	) {
+		n--;
+		/* allow to reuse list[n] later without re-growth */
+		output->has_empty_slot = 1;
+	}
+
+	return n;
+}
+
+static char **expand_variables(char **argv, unsigned expflags)
+{
+	int n;
+	char **list;
+	o_string output = NULL_O_STRING;
+
+	output.o_expflags = expflags;
+
+	n = 0;
+	for (;;) {
+		/* go to next list[n] */
+		output.ended_in_ifs = 0;
+		n = o_save_ptr(&output, n);
+
+		if (!*argv)
+			break;
+
+		/* expand argv[i] */
+		n = expand_vars_to_list(&output, n, *argv++);
+		/* if (!output->has_empty_slot) -- need this?? */
+			o_addchr(&output, '\0');
+	}
+	debug_print_list("expand_variables", &output, n);
+
+	/* output.data (malloced in one block) gets returned in "list" */
+	list = o_finalize_list(&output, n);
+	debug_print_strings("expand_variables[1]", list);
+	return list;
+}
+
+static char **expand_strvec_to_strvec(char **argv)
+{
+	return expand_variables(argv, EXP_FLAG_GLOB | EXP_FLAG_ESC_GLOB_CHARS);
+}
+
+#if defined(CMD_SINGLEWORD_NOGLOB) || defined(CMD_TEST2_SINGLEWORD_NOGLOB)
+static char **expand_strvec_to_strvec_singleword_noglob(char **argv)
+{
+	return expand_variables(argv, EXP_FLAG_SINGLEWORD);
+}
+#endif
+
+/* Used for expansion of right hand of assignments,
+ * $((...)), heredocs, variable expansion parts.
+ *
+ * NB: should NOT do globbing!
+ * "export v=/bin/c*; env | grep ^v=" outputs "v=/bin/c*"
+ */
+static char *expand_string_to_string(const char *str, int EXP_flags, int do_unbackslash)
+{
+#if !BASH_PATTERN_SUBST && !ENABLE_HUSH_CASE
+	const int do_unbackslash = 1;
+	const int EXP_flags = EXP_FLAG_ESC_GLOB_CHARS;
+#endif
+	char *argv[2], **list;
+
+	debug_printf_expand("string_to_string<='%s'\n", str);
+	/* This is generally an optimization, but it also
+	 * handles "", which otherwise trips over !list[0] check below.
+	 * (is this ever happens that we actually get str="" here?)
+	 */
+	if (!strchr(str, SPECIAL_VAR_SYMBOL) && !strchr(str, '\\')) {
+		//TODO: Can use on strings with \ too, just unbackslash() them?
+		debug_printf_expand("string_to_string(fast)=>'%s'\n", str);
+		return xstrdup(str);
+	}
+
+	argv[0] = (char*)str;
+	argv[1] = NULL;
+	list = expand_variables(argv, EXP_flags | EXP_FLAG_SINGLEWORD);
+	if (!list[0]) {
+		/* Example where it happens:
+		 * x=; echo ${x:-"$@"}
+		 */
+		((char*)list)[0] = '\0';
+	} else {
+		if (HUSH_DEBUG)
+			if (list[1])
+				bb_simple_error_msg_and_die("BUG in varexp2");
+		/* actually, just move string 2*sizeof(char*) bytes back */
+		overlapping_strcpy((char*)list, list[0]);
+		if (do_unbackslash)
+			unbackslash((char*)list);
+	}
+	debug_printf_expand("string_to_string=>'%s'\n", (char*)list);
+	return (char*)list;
+}
+
+#if 0
+static char* expand_strvec_to_string(char **argv)
+{
+	char **list;
+
+	list = expand_variables(argv, EXP_FLAG_SINGLEWORD);
+	/* Convert all NULs to spaces */
+	if (list[0]) {
+		int n = 1;
+		while (list[n]) {
+			if (HUSH_DEBUG)
+				if (list[n-1] + strlen(list[n-1]) + 1 != list[n])
+					bb_error_msg_and_die("BUG in varexp3");
+			/* bash uses ' ' regardless of $IFS contents */
+			list[n][-1] = ' ';
+			n++;
+		}
+	}
+	overlapping_strcpy((char*)list, list[0] ? list[0] : "");
+	debug_printf_expand("strvec_to_string='%s'\n", (char*)list);
+	return (char*)list;
+}
+#endif
+
+static char **expand_assignments(char **argv, int count)
+{
+	int i;
+	char **p;
+
+	G.expanded_assignments = p = NULL;
+	/* Expand assignments into one string each */
+	for (i = 0; i < count; i++) {
+		p = add_string_to_strings(p,
+			expand_string_to_string(argv[i],
+				EXP_FLAG_ESC_GLOB_CHARS,
+				/*unbackslash:*/ 1
+			)
+		);
+		G.expanded_assignments = p;
+	}
+	G.expanded_assignments = NULL;
+	return p;
+}
+
+
+static void switch_off_special_sigs(unsigned mask)
+{
+	unsigned sig = 0;
+	while ((mask >>= 1) != 0) {
+		sig++;
+		if (!(mask & 1))
+			continue;
+#if ENABLE_HUSH_TRAP
+		if (G_traps) {
+			if (G_traps[sig] && !G_traps[sig][0])
+				/* trap is '', has to remain SIG_IGN */
+				continue;
+			free(G_traps[sig]);
+			G_traps[sig] = NULL;
+		}
+#endif
+		/* We are here only if no trap or trap was not '' */
+		install_sighandler(sig, SIG_DFL);
+	}
+}
+
+#if BB_MMU
+/* never called */
+void re_execute_shell(char ***to_free, const char *s,
+		char *g_argv0, char **g_argv,
+		char **builtin_argv) NORETURN;
+
+static void reset_traps_to_defaults(void)
+{
+	/* This function is always called in a child shell
+	 * after fork (not vfork, NOMMU doesn't use this function).
+	 */
+	IF_HUSH_TRAP(unsigned sig;)
+	unsigned mask;
+
+	/* Child shells are not interactive.
+	 * SIGTTIN/SIGTTOU/SIGTSTP should not have special handling.
+	 * Testcase: (while :; do :; done) + ^Z should background.
+	 * Same goes for SIGTERM, SIGHUP, SIGINT.
+	 */
+	mask = (G.special_sig_mask & SPECIAL_INTERACTIVE_SIGS) | G_fatal_sig_mask;
+	if (!G_traps && !mask)
+		return; /* already no traps and no special sigs */
+
+	/* Switch off special sigs */
+	switch_off_special_sigs(mask);
+# if ENABLE_HUSH_JOB
+	G_fatal_sig_mask = 0;
+# endif
+	G.special_sig_mask &= ~SPECIAL_INTERACTIVE_SIGS;
+	/* SIGQUIT,SIGCHLD and maybe SPECIAL_JOBSTOP_SIGS
+	 * remain set in G.special_sig_mask */
+
+# if ENABLE_HUSH_TRAP
+	if (!G_traps)
+		return;
+
+	/* Reset all sigs to default except ones with empty traps */
+	for (sig = 0; sig < NSIG; sig++) {
+		if (!G_traps[sig])
+			continue; /* no trap: nothing to do */
+		if (!G_traps[sig][0])
+			continue; /* empty trap: has to remain SIG_IGN */
+		/* sig has non-empty trap, reset it: */
+		free(G_traps[sig]);
+		G_traps[sig] = NULL;
+		/* There is no signal for trap 0 (EXIT) */
+		if (sig == 0)
+			continue;
+		install_sighandler(sig, pick_sighandler(sig));
+	}
+# endif
+}
+
+#else /* !BB_MMU */
+
+static void re_execute_shell(char ***to_free, const char *s,
+		char *g_argv0, char **g_argv,
+		char **builtin_argv) NORETURN;
+static void re_execute_shell(char ***to_free, const char *s,
+		char *g_argv0, char **g_argv,
+		char **builtin_argv)
+{
+# define NOMMU_HACK_FMT ("-$%x:%x:%x:%x:%x:%llx" IF_HUSH_LOOPS(":%x"))
+	/* delims + 2 * (number of bytes in printed hex numbers) */
+	char param_buf[sizeof(NOMMU_HACK_FMT) + 2 * (sizeof(int)*6 + sizeof(long long)*1)];
+	char *heredoc_argv[4];
+	struct variable *cur;
+# if ENABLE_HUSH_FUNCTIONS
+	struct function *funcp;
+# endif
+	char **argv, **pp;
+	unsigned cnt;
+	unsigned long long empty_trap_mask;
+
+	if (!g_argv0) { /* heredoc */
+		argv = heredoc_argv;
+		argv[0] = (char *) G.argv0_for_re_execing;
+		argv[1] = (char *) "-<";
+		argv[2] = (char *) s;
+		argv[3] = NULL;
+		pp = &argv[3]; /* used as pointer to empty environment */
+		goto do_exec;
+	}
+
+	cnt = 0;
+	pp = builtin_argv;
+	if (pp) while (*pp++)
+		cnt++;
+
+	empty_trap_mask = 0;
+	if (G_traps) {
+		int sig;
+		for (sig = 1; sig < NSIG; sig++) {
+			if (G_traps[sig] && !G_traps[sig][0])
+				empty_trap_mask |= 1LL << sig;
+		}
+	}
+
+	sprintf(param_buf, NOMMU_HACK_FMT
+			, (unsigned) G.root_pid
+			, (unsigned) G.root_ppid
+			, (unsigned) G.last_bg_pid
+			, (unsigned) G.last_exitcode
+			, cnt
+			, empty_trap_mask
+			IF_HUSH_LOOPS(, G.depth_of_loop)
+			);
+# undef NOMMU_HACK_FMT
+	/* 1:hush 2:-$<pid>:<pid>:<exitcode>:<etc...> <vars...> <funcs...>
+	 * 3:-c 4:<cmd> 5:<arg0> <argN...> 6:NULL
+	 */
+	cnt += 6;
+	for (cur = G.top_var; cur; cur = cur->next) {
+		if (!cur->flg_export || cur->flg_read_only)
+			cnt += 2;
+	}
+# if ENABLE_HUSH_FUNCTIONS
+	for (funcp = G.top_func; funcp; funcp = funcp->next)
+		cnt += 3;
+# endif
+	pp = g_argv;
+	while (*pp++)
+		cnt++;
+	*to_free = argv = pp = xzalloc(sizeof(argv[0]) * cnt);
+	*pp++ = (char *) G.argv0_for_re_execing;
+	*pp++ = param_buf;
+	for (cur = G.top_var; cur; cur = cur->next) {
+		if (strcmp(cur->varstr, hush_version_str) == 0)
+			continue;
+		if (cur->flg_read_only) {
+			*pp++ = (char *) "-R";
+			*pp++ = cur->varstr;
+		} else if (!cur->flg_export) {
+			*pp++ = (char *) "-V";
+			*pp++ = cur->varstr;
+		}
+	}
+# if ENABLE_HUSH_FUNCTIONS
+	for (funcp = G.top_func; funcp; funcp = funcp->next) {
+		*pp++ = (char *) "-F";
+		*pp++ = funcp->name;
+		*pp++ = funcp->body_as_string;
+	}
+# endif
+	/* We can pass activated traps here. Say, -Tnn:trap_string
+	 *
+	 * However, POSIX says that subshells reset signals with traps
+	 * to SIG_DFL.
+	 * I tested bash-3.2 and it not only does that with true subshells
+	 * of the form ( list ), but with any forked children shells.
+	 * I set trap "echo W" WINCH; and then tried:
+	 *
+	 * { echo 1; sleep 20; echo 2; } &
+	 * while true; do echo 1; sleep 20; echo 2; break; done &
+	 * true | { echo 1; sleep 20; echo 2; } | cat
+	 *
+	 * In all these cases sending SIGWINCH to the child shell
+	 * did not run the trap. If I add trap "echo V" WINCH;
+	 * _inside_ group (just before echo 1), it works.
+	 *
+	 * I conclude it means we don't need to pass active traps here.
+	 */
+	*pp++ = (char *) "-c";
+	*pp++ = (char *) s;
+	if (builtin_argv) {
+		while (*++builtin_argv)
+			*pp++ = *builtin_argv;
+		*pp++ = (char *) "";
+	}
+	*pp++ = g_argv0;
+	while (*g_argv)
+		*pp++ = *g_argv++;
+	/* *pp = NULL; - is already there */
+	pp = environ;
+
+ do_exec:
+	debug_printf_exec("re_execute_shell pid:%d cmd:'%s'\n", getpid(), s);
+	/* Don't propagate SIG_IGN to the child */
+	if (SPECIAL_JOBSTOP_SIGS != 0)
+		switch_off_special_sigs(G.special_sig_mask & SPECIAL_JOBSTOP_SIGS);
+	execve(bb_busybox_exec_path, argv, pp);
+	/* Fallback. Useful for init=/bin/hush usage etc */
+	if (argv[0][0] == '/')
+		execve(argv[0], argv, pp);
+	xfunc_error_retval = 127;
+	bb_simple_error_msg_and_die("can't re-execute the shell");
+}
+#endif  /* !BB_MMU */
+
+
+static int run_and_free_list(struct pipe *pi);
+
+/* Executing from string: eval, sh -c '...'
+ *          or from file: /etc/profile, . file, sh <script>, sh (intereactive)
+ * end_trigger controls how often we stop parsing
+ * NUL: parse all, execute, return
+ * ';': parse till ';' or newline, execute, repeat till EOF
+ */
+static void parse_and_run_stream(struct in_str *inp, int end_trigger)
+{
+	/* Why we need empty flag?
+	 * An obscure corner case "false; ``; echo $?":
+	 * empty command in `` should still set $? to 0.
+	 * But we can't just set $? to 0 at the start,
+	 * this breaks "false; echo `echo $?`" case.
+	 */
+	bool empty = 1;
+	while (1) {
+		struct pipe *pipe_list;
+
+#if ENABLE_HUSH_INTERACTIVE
+		if (end_trigger == ';') {
+			G.promptmode = 0; /* PS1 */
+			debug_printf_prompt("%s promptmode=%d\n", __func__, G.promptmode);
+		}
+#endif
+		pipe_list = parse_stream(NULL, NULL, inp, end_trigger);
+		if (!pipe_list || pipe_list == ERR_PTR) { /* EOF/error */
+			/* If we are in "big" script
+			 * (not in `cmd` or something similar)...
+			 */
+			if (pipe_list == ERR_PTR && end_trigger == ';') {
+				/* Discard cached input (rest of line) */
+				int ch = inp->last_char;
+				while (ch != EOF && ch != '\n') {
+					//bb_error_msg("Discarded:'%c'", ch);
+					ch = i_getch(inp);
+				}
+				/* Force prompt */
+				inp->p = NULL;
+				/* This stream isn't empty */
+				empty = 0;
+				continue;
+			}
+			if (!pipe_list && empty)
+				G.last_exitcode = 0;
+			break;
+		}
+		debug_print_tree(pipe_list, 0);
+		debug_printf_exec("parse_and_run_stream: run_and_free_list\n");
+		run_and_free_list(pipe_list);
+		empty = 0;
+		if (G_flag_return_in_progress == 1)
+			break;
+	}
+}
+
+static void parse_and_run_string(const char *s)
+{
+	struct in_str input;
+	//IF_HUSH_LINENO_VAR(unsigned sv = G.parse_lineno;)
+
+	setup_string_in_str(&input, s);
+	parse_and_run_stream(&input, '\0');
+	//IF_HUSH_LINENO_VAR(G.parse_lineno = sv;)
+}
+
+static void parse_and_run_file(HFILE *fp)
+{
+	struct in_str input;
+	IF_HUSH_LINENO_VAR(unsigned sv = G.parse_lineno;)
+
+	IF_HUSH_LINENO_VAR(G.parse_lineno = 1;)
+	setup_file_in_str(&input, fp);
+	parse_and_run_stream(&input, ';');
+	IF_HUSH_LINENO_VAR(G.parse_lineno = sv;)
+}
+
+#if ENABLE_HUSH_TICK
+static int generate_stream_from_string(const char *s, pid_t *pid_p)
+{
+	pid_t pid;
+	int channel[2];
+# if !BB_MMU
+	char **to_free = NULL;
+# endif
+
+	xpipe(channel);
+	pid = BB_MMU ? xfork() : xvfork();
+	if (pid == 0) { /* child */
+		disable_restore_tty_pgrp_on_exit();
+		/* Process substitution is not considered to be usual
+		 * 'command execution'.
+		 * SUSv3 says ctrl-Z should be ignored, ctrl-C should not.
+		 */
+		bb_signals(0
+			+ (1 << SIGTSTP)
+			+ (1 << SIGTTIN)
+			+ (1 << SIGTTOU)
+			, SIG_IGN);
+		close(channel[0]); /* NB: close _first_, then move fd! */
+		xmove_fd(channel[1], 1);
+# if ENABLE_HUSH_TRAP
+		/* Awful hack for `trap` or $(trap).
+		 *
+		 * http://www.opengroup.org/onlinepubs/009695399/utilities/trap.html
+		 * contains an example where "trap" is executed in a subshell:
+		 *
+		 * save_traps=$(trap)
+		 * ...
+		 * eval "$save_traps"
+		 *
+		 * Standard does not say that "trap" in subshell shall print
+		 * parent shell's traps. It only says that its output
+		 * must have suitable form, but then, in the above example
+		 * (which is not supposed to be normative), it implies that.
+		 *
+		 * bash (and probably other shell) does implement it
+		 * (traps are reset to defaults, but "trap" still shows them),
+		 * but as a result, "trap" logic is hopelessly messed up:
+		 *
+		 * # trap
+		 * trap -- 'echo Ho' SIGWINCH  <--- we have a handler
+		 * # (trap)        <--- trap is in subshell - no output (correct, traps are reset)
+		 * # true | trap   <--- trap is in subshell - no output (ditto)
+		 * # echo `true | trap`    <--- in subshell - output (but traps are reset!)
+		 * trap -- 'echo Ho' SIGWINCH
+		 * # echo `(trap)`         <--- in subshell in subshell - output
+		 * trap -- 'echo Ho' SIGWINCH
+		 * # echo `true | (trap)`  <--- in subshell in subshell in subshell - output!
+		 * trap -- 'echo Ho' SIGWINCH
+		 *
+		 * The rules when to forget and when to not forget traps
+		 * get really complex and nonsensical.
+		 *
+		 * Our solution: ONLY bare $(trap) or `trap` is special.
+		 */
+		s = skip_whitespace(s);
+		if (is_prefixed_with(s, "trap")
+		 && skip_whitespace(s + 4)[0] == '\0'
+		) {
+			static const char *const argv[] = { NULL, NULL };
+			builtin_trap((char**)argv);
+			fflush_all(); /* important */
+			_exit(0);
+		}
+# endif
+# if BB_MMU
+		/* Prevent it from trying to handle ctrl-z etc */
+		IF_HUSH_JOB(G.run_list_level = 1;)
+		CLEAR_RANDOM_T(&G.random_gen); /* or else $RANDOM repeats in child */
+		reset_traps_to_defaults();
+		IF_HUSH_MODE_X(G.x_mode_depth++;)
+		//bb_error_msg("%s: ++x_mode_depth=%d", __func__, G.x_mode_depth);
+		parse_and_run_string(s);
+		_exit(G.last_exitcode);
+# else
+	/* We re-execute after vfork on NOMMU. This makes this script safe:
+	 * yes "0123456789012345678901234567890" | dd bs=32 count=64k >BIG
+	 * huge=`cat BIG` # was blocking here forever
+	 * echo OK
+	 */
+		re_execute_shell(&to_free,
+				s,
+				G.global_argv[0],
+				G.global_argv + 1,
+				NULL);
+# endif
+	}
+
+	/* parent */
+	*pid_p = pid;
+# if ENABLE_HUSH_FAST
+	G.count_SIGCHLD++;
+//bb_error_msg("[%d] fork in generate_stream_from_string:"
+//		" G.count_SIGCHLD:%d G.handled_SIGCHLD:%d",
+//		getpid(), G.count_SIGCHLD, G.handled_SIGCHLD);
+# endif
+	enable_restore_tty_pgrp_on_exit();
+# if !BB_MMU
+	free(to_free);
+# endif
+	close(channel[1]);
+	return channel[0];
+}
+
+/* Return code is exit status of the process that is run. */
+static int process_command_subs(o_string *dest, const char *s)
+{
+	FILE *fp;
+	pid_t pid;
+	int status, ch, eol_cnt;
+
+	fp = xfdopen_for_read(generate_stream_from_string(s, &pid));
+
+	/* Now send results of command back into original context */
+	eol_cnt = 0;
+	while ((ch = getc(fp)) != EOF) {
+		if (ch == '\0')
+			continue;
+		if (ch == '\n') {
+			eol_cnt++;
+			continue;
+		}
+		while (eol_cnt) {
+			o_addchr(dest, '\n');
+			eol_cnt--;
+		}
+		o_addQchr(dest, ch);
+	}
+
+	debug_printf("done reading from `cmd` pipe, closing it\n");
+	fclose(fp);
+	/* We need to extract exitcode. Test case
+	 * "true; echo `sleep 1; false` $?"
+	 * should print 1 */
+	safe_waitpid(pid, &status, 0);
+	debug_printf("child exited. returning its exitcode:%d\n", WEXITSTATUS(status));
+	return WEXITSTATUS(status);
+}
+#endif /* ENABLE_HUSH_TICK */
+
+
+static void setup_heredoc(struct redir_struct *redir)
+{
+	struct fd_pair pair;
+	pid_t pid;
+	int len, written;
+	/* the _body_ of heredoc (misleading field name) */
+	const char *heredoc = redir->rd_filename;
+	char *expanded;
+#if !BB_MMU
+	char **to_free;
+#endif
+
+	expanded = NULL;
+	if (!(redir->rd_dup & HEREDOC_QUOTED)) {
+		expanded = encode_then_expand_string(heredoc);
+		if (expanded)
+			heredoc = expanded;
+	}
+	len = strlen(heredoc);
+
+	close(redir->rd_fd); /* often saves dup2+close in xmove_fd */
+	xpiped_pair(pair);
+	xmove_fd(pair.rd, redir->rd_fd);
+
+	/* Try writing without forking. Newer kernels have
+	 * dynamically growing pipes. Must use non-blocking write! */
+	ndelay_on(pair.wr);
+	while (1) {
+		written = write(pair.wr, heredoc, len);
+		if (written <= 0)
+			break;
+		len -= written;
+		if (len == 0) {
+			close(pair.wr);
+			free(expanded);
+			return;
+		}
+		heredoc += written;
+	}
+	ndelay_off(pair.wr);
+
+	/* Okay, pipe buffer was not big enough */
+	/* Note: we must not create a stray child (bastard? :)
+	 * for the unsuspecting parent process. Child creates a grandchild
+	 * and exits before parent execs the process which consumes heredoc
+	 * (that exec happens after we return from this function) */
+#if !BB_MMU
+	to_free = NULL;
+#endif
+	pid = xvfork();
+	if (pid == 0) {
+		/* child */
+		disable_restore_tty_pgrp_on_exit();
+		pid = BB_MMU ? xfork() : xvfork();
+		if (pid != 0)
+			_exit(0);
+		/* grandchild */
+		close(redir->rd_fd); /* read side of the pipe */
+#if BB_MMU
+		full_write(pair.wr, heredoc, len); /* may loop or block */
+		_exit(0);
+#else
+		/* Delegate blocking writes to another process */
+		xmove_fd(pair.wr, STDOUT_FILENO);
+		re_execute_shell(&to_free, heredoc, NULL, NULL, NULL);
+#endif
+	}
+	/* parent */
+#if ENABLE_HUSH_FAST
+	G.count_SIGCHLD++;
+//bb_error_msg("[%d] fork in setup_heredoc: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD);
+#endif
+	enable_restore_tty_pgrp_on_exit();
+#if !BB_MMU
+	free(to_free);
+#endif
+	close(pair.wr);
+	free(expanded);
+	wait(NULL); /* wait till child has died */
+}
+
+struct squirrel {
+	int orig_fd;
+	int moved_to;
+	/* moved_to = n: fd was moved to n; restore back to orig_fd after redir */
+	/* moved_to = -1: fd was opened by redirect; close orig_fd after redir */
+};
+
+static struct squirrel *append_squirrel(struct squirrel *sq, int i, int orig, int moved)
+{
+	sq = xrealloc(sq, (i + 2) * sizeof(sq[0]));
+	sq[i].orig_fd = orig;
+	sq[i].moved_to = moved;
+	sq[i+1].orig_fd = -1; /* end marker */
+	return sq;
+}
+
+static struct squirrel *add_squirrel(struct squirrel *sq, int fd, int avoid_fd)
+{
+	int moved_to;
+	int i;
+
+	i = 0;
+	if (sq) for (; sq[i].orig_fd >= 0; i++) {
+		/* If we collide with an already moved fd... */
+		if (fd == sq[i].moved_to) {
+			sq[i].moved_to = dup_CLOEXEC(sq[i].moved_to, avoid_fd);
+			debug_printf_redir("redirect_fd %d: already busy, moving to %d\n", fd, sq[i].moved_to);
+			if (sq[i].moved_to < 0) /* what? */
+				xfunc_die();
+			return sq;
+		}
+		if (fd == sq[i].orig_fd) {
+			/* Example: echo Hello >/dev/null 1>&2 */
+			debug_printf_redir("redirect_fd %d: already moved\n", fd);
+			return sq;
+		}
+	}
+
+	/* If this fd is open, we move and remember it; if it's closed, moved_to = -1 */
+	moved_to = dup_CLOEXEC(fd, avoid_fd);
+	debug_printf_redir("redirect_fd %d: previous fd is moved to %d (-1 if it was closed)\n", fd, moved_to);
+	if (moved_to < 0 && errno != EBADF)
+		xfunc_die();
+	return append_squirrel(sq, i, fd, moved_to);
+}
+
+static struct squirrel *add_squirrel_closed(struct squirrel *sq, int fd)
+{
+	int i;
+
+	i = 0;
+	if (sq) for (; sq[i].orig_fd >= 0; i++) {
+		/* If we collide with an already moved fd... */
+		if (fd == sq[i].orig_fd) {
+			/* Examples:
+			 * "echo 3>FILE 3>&- 3>FILE"
+			 * "echo 3>&- 3>FILE"
+			 * No need for last redirect to insert
+			 * another "need to close 3" indicator.
+			 */
+			debug_printf_redir("redirect_fd %d: already moved or closed\n", fd);
+			return sq;
+		}
+	}
+
+	debug_printf_redir("redirect_fd %d: previous fd was closed\n", fd);
+	return append_squirrel(sq, i, fd, -1);
+}
+
+/* fd: redirect wants this fd to be used (e.g. 3>file).
+ * Move all conflicting internally used fds,
+ * and remember them so that we can restore them later.
+ */
+static int save_fd_on_redirect(int fd, int avoid_fd, struct squirrel **sqp)
+{
+	if (avoid_fd < 9) /* the important case here is that it can be -1 */
+		avoid_fd = 9;
+
+#if ENABLE_HUSH_INTERACTIVE
+	if (fd != 0 /* don't trigger for G_interactive_fd == 0 (that's "not interactive" flag) */
+	 && fd == G_interactive_fd
+	) {
+		/* Testcase: "ls -l /proc/$$/fd 255>&-" should work */
+		G_interactive_fd = xdup_CLOEXEC_and_close(G_interactive_fd, avoid_fd);
+		debug_printf_redir("redirect_fd %d: matches interactive_fd, moving it to %d\n", fd, G_interactive_fd);
+		return 1; /* "we closed fd" */
+	}
+#endif
+	/* Are we called from setup_redirects(squirrel==NULL)
+	 * in redirect in a [v]forked child?
+	 */
+	if (sqp == NULL) {
+		/* No need to move script fds.
+		 * For NOMMU case, it's actively wrong: we'd change ->fd
+		 * fields in memory for the parent, but parent's fds
+		 * aren't moved, it would use wrong fd!
+		 * Reproducer: "cmd 3>FILE" in script.
+		 * If we would call move_HFILEs_on_redirect(), child would:
+		 *  fcntl64(3, F_DUPFD_CLOEXEC, 10)   = 10
+		 *  close(3)                          = 0
+		 * and change ->fd to 10 if fd#3 is a script fd. WRONG.
+		 */
+		//bb_error_msg("sqp == NULL: [v]forked child");
+		return 0;
+	}
+
+	/* If this one of script's fds? */
+	if (move_HFILEs_on_redirect(fd, avoid_fd))
+		return 1; /* yes. "we closed fd" (actually moved it) */
+
+	/* Are we called for "exec 3>FILE"? Came through
+	 * redirect_and_varexp_helper(squirrel=ERR_PTR) -> setup_redirects(ERR_PTR)
+	 * This case used to fail for this script:
+	 *  exec 3>FILE
+	 *  echo Ok
+	 *  ...100000 more lines...
+	 *  echo Ok
+	 * as follows:
+	 *  read(3, "exec 3>FILE\necho Ok\necho Ok"..., 1024) = 1024
+	 *  open("FILE", O_WRONLY|O_CREAT|O_TRUNC|O_LARGEFILE, 0666) = 4
+	 *  dup2(4, 3)                        = 3
+	 *  ^^^^^^^^ oops, we lost fd#3 opened to our script!
+	 *  close(4)                          = 0
+	 *  write(1, "Ok\n", 3)               = 3
+	 *  ...                               = 3
+	 *  write(1, "Ok\n", 3)               = 3
+	 *  read(3, 0x94fbc08, 1024)          = -1 EBADF (Bad file descriptor)
+	 *  ^^^^^^^^ oops, wrong fd!!!
+	 * With this case separate from sqp == NULL and *after* move_HFILEs,
+	 * it now works:
+	 */
+	if (sqp == ERR_PTR) {
+		/* Don't preserve redirected fds: exec is _meant_ to change these */
+		//bb_error_msg("sqp == ERR_PTR: exec >FILE");
+		return 0;
+	}
+
+	/* Check whether it collides with any open fds (e.g. stdio), save fds as needed */
+	*sqp = add_squirrel(*sqp, fd, avoid_fd);
+	return 0; /* "we did not close fd" */
+}
+
+static void restore_redirects(struct squirrel *sq)
+{
+	if (sq) {
+		int i;
+		for (i = 0; sq[i].orig_fd >= 0; i++) {
+			if (sq[i].moved_to >= 0) {
+				/* We simply die on error */
+				debug_printf_redir("restoring redirected fd from %d to %d\n", sq[i].moved_to, sq[i].orig_fd);
+				xmove_fd(sq[i].moved_to, sq[i].orig_fd);
+			} else {
+				/* cmd1 9>FILE; cmd2_should_see_fd9_closed */
+				debug_printf_redir("restoring redirected fd %d: closing it\n", sq[i].orig_fd);
+				close(sq[i].orig_fd);
+			}
+		}
+		free(sq);
+	}
+	if (G.HFILE_stdin
+	 && G.HFILE_stdin->fd > STDIN_FILENO
+	/* we compare > STDIN, not == STDIN, since hfgetc()
+	 * closes fd and sets ->fd to -1 if EOF is reached.
+	 * Testcase: echo 'pwd' | hush
+	 */
+	) {
+		/* Testcase: interactive "read r <FILE; echo $r; read r; echo $r".
+		 * Redirect moves ->fd to e.g. 10,
+		 * and it is not restored above (we do not restore script fds
+		 * after redirects, we just use new, "moved" fds).
+		 * However for stdin, get_user_input() -> read_line_input(),
+		 * and read builtin, depend on fd == STDIN_FILENO.
+		 */
+		debug_printf_redir("restoring %d to stdin\n", G.HFILE_stdin->fd);
+		xmove_fd(G.HFILE_stdin->fd, STDIN_FILENO);
+		G.HFILE_stdin->fd = STDIN_FILENO;
+	}
+
+	/* If moved, G_interactive_fd stays on new fd, not restoring it */
+}
+
+#if ENABLE_FEATURE_SH_STANDALONE && BB_MMU
+static void close_saved_fds_and_FILE_fds(void)
+{
+	if (G_interactive_fd)
+		close(G_interactive_fd);
+	close_all_HFILE_list();
+}
+#endif
+
+static int internally_opened_fd(int fd, struct squirrel *sq)
+{
+	int i;
+
+#if ENABLE_HUSH_INTERACTIVE
+	if (fd == G_interactive_fd)
+		return 1;
+#endif
+	/* If this one of script's fds? */
+	if (fd_in_HFILEs(fd))
+		return 1;
+
+	if (sq) for (i = 0; sq[i].orig_fd >= 0; i++) {
+		if (fd == sq[i].moved_to)
+			return 1;
+	}
+	return 0;
+}
+
+/* squirrel != NULL means we squirrel away copies of stdin, stdout,
+ * and stderr if they are redirected. */
+static int setup_redirects(struct command *prog, struct squirrel **sqp)
+{
+	struct redir_struct *redir;
+
+	for (redir = prog->redirects; redir; redir = redir->next) {
+		int newfd;
+		int closed;
+
+		if (redir->rd_type == REDIRECT_HEREDOC2) {
+			/* "rd_fd<<HERE" case */
+			save_fd_on_redirect(redir->rd_fd, /*avoid:*/ 0, sqp);
+			/* for REDIRECT_HEREDOC2, rd_filename holds _contents_
+			 * of the heredoc */
+			debug_printf_redir("set heredoc '%s'\n",
+					redir->rd_filename);
+			setup_heredoc(redir);
+			continue;
+		}
+
+		if (redir->rd_dup == REDIRFD_TO_FILE) {
+			/* "rd_fd<*>file" case (<*> is <,>,>>,<>) */
+			char *p;
+			int mode;
+
+			if (redir->rd_filename == NULL) {
+				/* Examples:
+				 * "cmd >" (no filename)
+				 * "cmd > <file" (2nd redirect starts too early)
+				 */
+				syntax_error("invalid redirect");
+				continue;
+			}
+			mode = redir_table[redir->rd_type].mode;
+			p = expand_string_to_string(redir->rd_filename,
+				EXP_FLAG_ESC_GLOB_CHARS, /*unbackslash:*/ 1);
+			newfd = open_or_warn(p, mode);
+			free(p);
+			if (newfd < 0) {
+				/* Error message from open_or_warn can be lost
+				 * if stderr has been redirected, but bash
+				 * and ash both lose it as well
+				 * (though zsh doesn't!)
+				 */
+				return 1;
+			}
+			if (newfd == redir->rd_fd && sqp) {
+				/* open() gave us precisely the fd we wanted.
+				 * This means that this fd was not busy
+				 * (not opened to anywhere).
+				 * Remember to close it on restore:
+				 */
+				*sqp = add_squirrel_closed(*sqp, newfd);
+				debug_printf_redir("redir to previously closed fd %d\n", newfd);
+			}
+		} else {
+			/* "rd_fd>&rd_dup" or "rd_fd>&-" case */
+			newfd = redir->rd_dup;
+		}
+
+		if (newfd == redir->rd_fd)
+			continue;
+
+		/* if "N>FILE": move newfd to redir->rd_fd */
+		/* if "N>&M": dup newfd to redir->rd_fd */
+		/* if "N>&-": close redir->rd_fd (newfd is REDIRFD_CLOSE) */
+
+		closed = save_fd_on_redirect(redir->rd_fd, /*avoid:*/ newfd, sqp);
+		if (newfd == REDIRFD_CLOSE) {
+			/* "N>&-" means "close me" */
+			if (!closed) {
+				/* ^^^ optimization: saving may already
+				 * have closed it. If not... */
+				close(redir->rd_fd);
+			}
+			/* Sometimes we do another close on restore, getting EBADF.
+			 * Consider "echo 3>FILE 3>&-"
+			 * first redirect remembers "need to close 3",
+			 * and second redirect closes 3! Restore code then closes 3 again.
+			 */
+		} else {
+			/* if newfd is a script fd or saved fd, simulate EBADF */
+			if (internally_opened_fd(newfd, sqp && sqp != ERR_PTR ? *sqp : NULL)) {
+				//errno = EBADF;
+				//bb_perror_msg_and_die("can't duplicate file descriptor");
+				newfd = -1; /* same effect as code above */
+			}
+			xdup2(newfd, redir->rd_fd);
+			if (redir->rd_dup == REDIRFD_TO_FILE)
+				/* "rd_fd > FILE" */
+				close(newfd);
+			/* else: "rd_fd > rd_dup" */
+		}
+	}
+	return 0;
+}
+
+static char *find_in_path(const char *arg)
+{
+	char *ret = NULL;
+	const char *PATH = get_local_var_value("PATH");
+
+	if (!PATH)
+		return NULL;
+
+	while (1) {
+		const char *end = strchrnul(PATH, ':');
+		int sz = end - PATH; /* must be int! */
+
+		free(ret);
+		if (sz != 0) {
+			ret = xasprintf("%.*s/%s", sz, PATH, arg);
+		} else {
+			/* We have xxx::yyyy in $PATH,
+			 * it means "use current dir" */
+			ret = xstrdup(arg);
+		}
+		if (access(ret, F_OK) == 0)
+			break;
+
+		if (*end == '\0') {
+			free(ret);
+			return NULL;
+		}
+		PATH = end + 1;
+	}
+
+	return ret;
+}
+
+static const struct built_in_command *find_builtin_helper(const char *name,
+		const struct built_in_command *x,
+		const struct built_in_command *end)
+{
+	while (x != end) {
+		if (strcmp(name, x->b_cmd) != 0) {
+			x++;
+			continue;
+		}
+		debug_printf_exec("found builtin '%s'\n", name);
+		return x;
+	}
+	return NULL;
+}
+static const struct built_in_command *find_builtin1(const char *name)
+{
+	return find_builtin_helper(name, bltins1, &bltins1[ARRAY_SIZE(bltins1)]);
+}
+static const struct built_in_command *find_builtin(const char *name)
+{
+	const struct built_in_command *x = find_builtin1(name);
+	if (x)
+		return x;
+	return find_builtin_helper(name, bltins2, &bltins2[ARRAY_SIZE(bltins2)]);
+}
+
+#if ENABLE_HUSH_JOB && EDITING_HAS_get_exe_name
+static const char * FAST_FUNC get_builtin_name(int i)
+{
+	if (/*i >= 0 && */ i < ARRAY_SIZE(bltins1)) {
+		return bltins1[i].b_cmd;
+	}
+	i -= ARRAY_SIZE(bltins1);
+	if (i < ARRAY_SIZE(bltins2)) {
+		return bltins2[i].b_cmd;
+	}
+	return NULL;
+}
+#endif
+
+static void remove_nested_vars(void)
+{
+	struct variable *cur;
+	struct variable **cur_pp;
+
+	cur_pp = &G.top_var;
+	while ((cur = *cur_pp) != NULL) {
+		if (cur->var_nest_level <= G.var_nest_level) {
+			cur_pp = &cur->next;
+			continue;
+		}
+		/* Unexport */
+		if (cur->flg_export) {
+			debug_printf_env("unexporting nested '%s'/%u\n", cur->varstr, cur->var_nest_level);
+			bb_unsetenv(cur->varstr);
+		}
+		/* Remove from global list */
+		*cur_pp = cur->next;
+		/* Free */
+		if (!cur->max_len) {
+			debug_printf_env("freeing nested '%s'/%u\n", cur->varstr, cur->var_nest_level);
+			free(cur->varstr);
+		}
+		free(cur);
+	}
+}
+
+static void enter_var_nest_level(void)
+{
+	G.var_nest_level++;
+	debug_printf_env("var_nest_level++ %u\n", G.var_nest_level);
+
+	/* Try:	f() { echo -n .; f; }; f
+	 * struct variable::var_nest_level is uint16_t,
+	 * thus limiting recursion to < 2^16.
+	 * In any case, with 8 Mbyte stack SEGV happens
+	 * not too long after 2^16 recursions anyway.
+	 */
+	if (G.var_nest_level > 0xff00)
+		bb_error_msg_and_die("fatal recursion (depth %u)", G.var_nest_level);
+}
+
+static void leave_var_nest_level(void)
+{
+	G.var_nest_level--;
+	debug_printf_env("var_nest_level-- %u\n", G.var_nest_level);
+	if (HUSH_DEBUG && (int)G.var_nest_level < 0)
+		bb_simple_error_msg_and_die("BUG: nesting underflow");
+
+	remove_nested_vars();
+}
+
+#if ENABLE_HUSH_FUNCTIONS
+static struct function **find_function_slot(const char *name)
+{
+	struct function *funcp;
+	struct function **funcpp = &G.top_func;
+
+	while ((funcp = *funcpp) != NULL) {
+		if (strcmp(name, funcp->name) == 0) {
+			debug_printf_exec("found function '%s'\n", name);
+			break;
+		}
+		funcpp = &funcp->next;
+	}
+	return funcpp;
+}
+
+static ALWAYS_INLINE const struct function *find_function(const char *name)
+{
+	const struct function *funcp = *find_function_slot(name);
+	return funcp;
+}
+
+/* Note: takes ownership on name ptr */
+static struct function *new_function(char *name)
+{
+	struct function **funcpp = find_function_slot(name);
+	struct function *funcp = *funcpp;
+
+	if (funcp != NULL) {
+		struct command *cmd = funcp->parent_cmd;
+		debug_printf_exec("func %p parent_cmd %p\n", funcp, cmd);
+		if (!cmd) {
+			debug_printf_exec("freeing & replacing function '%s'\n", funcp->name);
+			free(funcp->name);
+			/* Note: if !funcp->body, do not free body_as_string!
+			 * This is a special case of "-F name body" function:
+			 * body_as_string was not malloced! */
+			if (funcp->body) {
+				free_pipe_list(funcp->body);
+# if !BB_MMU
+				free(funcp->body_as_string);
+# endif
+			}
+		} else {
+			debug_printf_exec("reinserting in tree & replacing function '%s'\n", funcp->name);
+			cmd->argv[0] = funcp->name;
+			cmd->group = funcp->body;
+# if !BB_MMU
+			cmd->group_as_string = funcp->body_as_string;
+# endif
+		}
+	} else {
+		debug_printf_exec("remembering new function '%s'\n", name);
+		funcp = *funcpp = xzalloc(sizeof(*funcp));
+		/*funcp->next = NULL;*/
+	}
+
+	funcp->name = name;
+	return funcp;
+}
+
+# if ENABLE_HUSH_UNSET
+static void unset_func(const char *name)
+{
+	struct function **funcpp = find_function_slot(name);
+	struct function *funcp = *funcpp;
+
+	if (funcp != NULL) {
+		debug_printf_exec("freeing function '%s'\n", funcp->name);
+		*funcpp = funcp->next;
+		/* funcp is unlinked now, deleting it.
+		 * Note: if !funcp->body, the function was created by
+		 * "-F name body", do not free ->body_as_string
+		 * and ->name as they were not malloced. */
+		if (funcp->body) {
+			free_pipe_list(funcp->body);
+			free(funcp->name);
+#  if !BB_MMU
+			free(funcp->body_as_string);
+#  endif
+		}
+		free(funcp);
+	}
+}
+# endif
+
+# if BB_MMU
+#define exec_function(to_free, funcp, argv) \
+	exec_function(funcp, argv)
+# endif
+static void exec_function(char ***to_free,
+		const struct function *funcp,
+		char **argv) NORETURN;
+static void exec_function(char ***to_free,
+		const struct function *funcp,
+		char **argv)
+{
+# if BB_MMU
+	int n;
+
+	argv[0] = G.global_argv[0];
+	G.global_argv = argv;
+	G.global_argc = n = 1 + string_array_len(argv + 1);
+
+// Example when we are here: "cmd | func"
+// func will run with saved-redirect fds open.
+// $ f() { echo /proc/self/fd/*; }
+// $ true | f
+// /proc/self/fd/0 /proc/self/fd/1 /proc/self/fd/2 /proc/self/fd/255 /proc/self/fd/3
+// stdio^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ G_interactive_fd^ DIR fd for glob
+// Same in script:
+// $ . ./SCRIPT
+// /proc/self/fd/0 /proc/self/fd/1 /proc/self/fd/2 /proc/self/fd/255 /proc/self/fd/3 /proc/self/fd/4
+// stdio^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ G_interactive_fd^ opened ./SCRIPT DIR fd for glob
+// They are CLOEXEC so external programs won't see them, but
+// for "more correctness" we might want to close those extra fds here:
+//?	close_saved_fds_and_FILE_fds();
+
+	/* "we are in a function, ok to use return" */
+	G_flag_return_in_progress = -1;
+	enter_var_nest_level();
+	IF_HUSH_LOCAL(G.func_nest_level++;)
+
+	/* On MMU, funcp->body is always non-NULL */
+	n = run_list(funcp->body);
+	_exit(n);
+# else
+//?	close_saved_fds_and_FILE_fds();
+
+//TODO: check whether "true | func_with_return" works
+
+	re_execute_shell(to_free,
+			funcp->body_as_string,
+			G.global_argv[0],
+			argv + 1,
+			NULL);
+# endif
+}
+
+static int run_function(const struct function *funcp, char **argv)
+{
+	int rc;
+	save_arg_t sv;
+	smallint sv_flg;
+
+	save_and_replace_G_args(&sv, argv);
+
+	/* "We are in function, ok to use return" */
+	sv_flg = G_flag_return_in_progress;
+	G_flag_return_in_progress = -1;
+
+	/* Make "local" variables properly shadow previous ones */
+	IF_HUSH_LOCAL(enter_var_nest_level();)
+	IF_HUSH_LOCAL(G.func_nest_level++;)
+
+	/* On MMU, funcp->body is always non-NULL */
+# if !BB_MMU
+	if (!funcp->body) {
+		/* Function defined by -F */
+		parse_and_run_string(funcp->body_as_string);
+		rc = G.last_exitcode;
+	} else
+# endif
+	{
+		rc = run_list(funcp->body);
+	}
+
+	IF_HUSH_LOCAL(G.func_nest_level--;)
+	IF_HUSH_LOCAL(leave_var_nest_level();)
+
+	G_flag_return_in_progress = sv_flg;
+# if ENABLE_HUSH_TRAP
+	debug_printf_exec("G.return_exitcode=-1\n");
+	G.return_exitcode = -1; /* invalidate stashed return value */
+# endif
+
+	restore_G_args(&sv, argv);
+
+	return rc;
+}
+#endif /* ENABLE_HUSH_FUNCTIONS */
+
+
+#if BB_MMU
+#define exec_builtin(to_free, x, argv) \
+	exec_builtin(x, argv)
+#else
+#define exec_builtin(to_free, x, argv) \
+	exec_builtin(to_free, argv)
+#endif
+static void exec_builtin(char ***to_free,
+		const struct built_in_command *x,
+		char **argv) NORETURN;
+static void exec_builtin(char ***to_free,
+		const struct built_in_command *x,
+		char **argv)
+{
+#if BB_MMU
+	int rcode;
+//?	close_saved_fds_and_FILE_fds();
+	rcode = x->b_function(argv);
+	fflush_all();
+	_exit(rcode);
+#else
+	fflush_all();
+	/* On NOMMU, we must never block!
+	 * Example: { sleep 99 | read line; } & echo Ok
+	 */
+	re_execute_shell(to_free,
+			argv[0],
+			G.global_argv[0],
+			G.global_argv + 1,
+			argv);
+#endif
+}
+
+
+static void execvp_or_die(char **argv) NORETURN;
+static void execvp_or_die(char **argv)
+{
+	int e;
+	debug_printf_exec("execing '%s'\n", argv[0]);
+	/* Don't propagate SIG_IGN to the child */
+	if (SPECIAL_JOBSTOP_SIGS != 0)
+		switch_off_special_sigs(G.special_sig_mask & SPECIAL_JOBSTOP_SIGS);
+	execvp(argv[0], argv);
+	e = 2;
+	if (errno == EACCES) e = 126;
+	if (errno == ENOENT) e = 127;
+	bb_perror_msg("can't execute '%s'", argv[0]);
+	_exit(e);
+}
+
+#if ENABLE_HUSH_MODE_X
+static void x_mode_print_optionally_squoted(const char *str)
+{
+	unsigned len;
+	const char *cp;
+
+	cp = str;
+
+	/* the set of chars which-cause-string-to-be-squoted mimics bash */
+	/* test a char with: bash -c 'set -x; echo "CH"' */
+	if (str[strcspn(str, "\\\"'`$(){}[]<>;#&|~*?!^"
+			" " "\001\002\003\004\005\006\007"
+			"\010\011\012\013\014\015\016\017"
+			"\020\021\022\023\024\025\026\027"
+			"\030\031\032\033\034\035\036\037"
+			)
+		] == '\0'
+	) {
+		/* string has no special chars */
+		x_mode_addstr(str);
+		return;
+	}
+
+	cp = str;
+	for (;;) {
+		/* print '....' up to EOL or first squote */
+		len = (int)(strchrnul(cp, '\'') - cp);
+		if (len != 0) {
+			x_mode_addchr('\'');
+			x_mode_addblock(cp, len);
+			x_mode_addchr('\'');
+			cp += len;
+		}
+		if (*cp == '\0')
+			break;
+		/* string contains squote(s), print them as \' */
+		x_mode_addchr('\\');
+		x_mode_addchr('\'');
+		cp++;
+	}
+}
+static void dump_cmd_in_x_mode(char **argv)
+{
+	if (G_x_mode && argv) {
+		unsigned n;
+
+		/* "+[+++...][ cmd...]\n\0" */
+		x_mode_prefix();
+		n = 0;
+		while (argv[n]) {
+			x_mode_addchr(' ');
+			if (argv[n][0] == '\0') {
+				x_mode_addchr('\'');
+				x_mode_addchr('\'');
+			} else {
+				x_mode_print_optionally_squoted(argv[n]);
+			}
+			n++;
+		}
+		x_mode_flush();
+	}
+}
+#else
+# define dump_cmd_in_x_mode(argv) ((void)0)
+#endif
+
+#if ENABLE_HUSH_COMMAND
+static void if_command_vV_print_and_exit(char opt_vV, char *cmd, const char *explanation)
+{
+	char *to_free;
+
+	if (!opt_vV)
+		return;
+
+	to_free = NULL;
+	if (!explanation) {
+		char *path = getenv("PATH");
+		explanation = to_free = find_executable(cmd, &path); /* path == NULL is ok */
+		if (!explanation)
+			_exit(1); /* PROG was not found */
+		if (opt_vV != 'V')
+			cmd = to_free; /* -v PROG prints "/path/to/PROG" */
+	}
+	printf((opt_vV == 'V') ? "%s is %s\n" : "%s\n", cmd, explanation);
+	free(to_free);
+	fflush_all();
+	_exit(0);
+}
+#else
+# define if_command_vV_print_and_exit(a,b,c) ((void)0)
+#endif
+
+#if BB_MMU
+#define pseudo_exec_argv(nommu_save, argv, assignment_cnt, argv_expanded) \
+	pseudo_exec_argv(argv, assignment_cnt, argv_expanded)
+#define pseudo_exec(nommu_save, command, argv_expanded) \
+	pseudo_exec(command, argv_expanded)
+#endif
+
+/* Called after [v]fork() in run_pipe, or from builtin_exec.
+ * Never returns.
+ * Don't exit() here.  If you don't exec, use _exit instead.
+ * The at_exit handlers apparently confuse the calling process,
+ * in particular stdin handling. Not sure why? -- because of vfork! (vda)
+ */
+static void pseudo_exec_argv(nommu_save_t *nommu_save,
+		char **argv, int assignment_cnt,
+		char **argv_expanded) NORETURN;
+static NOINLINE void pseudo_exec_argv(nommu_save_t *nommu_save,
+		char **argv, int assignment_cnt,
+		char **argv_expanded)
+{
+	const struct built_in_command *x;
+	struct variable **sv_shadowed;
+	char **new_env;
+	IF_HUSH_COMMAND(char opt_vV = 0;)
+	IF_HUSH_FUNCTIONS(const struct function *funcp;)
+
+	new_env = expand_assignments(argv, assignment_cnt);
+	dump_cmd_in_x_mode(new_env);
+
+	if (!argv[assignment_cnt]) {
+		/* Case when we are here: ... | var=val | ...
+		 * (note that we do not exit early, i.e., do not optimize out
+		 * expand_assignments(): think about ... | var=`sleep 1` | ...
+		 */
+		free_strings(new_env);
+		_exit(EXIT_SUCCESS);
+	}
+
+	sv_shadowed = G.shadowed_vars_pp;
+#if BB_MMU
+	G.shadowed_vars_pp = NULL; /* "don't save, free them instead" */
+#else
+	G.shadowed_vars_pp = &nommu_save->old_vars;
+	G.var_nest_level++;
+#endif
+	set_vars_and_save_old(new_env);
+	G.shadowed_vars_pp = sv_shadowed;
+
+	if (argv_expanded) {
+		argv = argv_expanded;
+	} else {
+		argv = expand_strvec_to_strvec(argv + assignment_cnt);
+#if !BB_MMU
+		nommu_save->argv = argv;
+#endif
+	}
+	dump_cmd_in_x_mode(argv);
+
+#if ENABLE_FEATURE_SH_STANDALONE || BB_MMU
+	if (strchr(argv[0], '/') != NULL)
+		goto skip;
+#endif
+
+#if ENABLE_HUSH_FUNCTIONS
+	/* Check if the command matches any functions (this goes before bltins) */
+	funcp = find_function(argv[0]);
+	if (funcp)
+		exec_function(&nommu_save->argv_from_re_execing, funcp, argv);
+#endif
+
+#if ENABLE_HUSH_COMMAND
+	/* "command BAR": run BAR without looking it up among functions
+	 * "command -v BAR": print "BAR" or "/path/to/BAR"; or exit 1
+	 * "command -V BAR": print "BAR is {a function,a shell builtin,/path/to/BAR}"
+	 */
+	while (strcmp(argv[0], "command") == 0 && argv[1]) {
+		char *p;
+
+		argv++;
+		p = *argv;
+		if (p[0] != '-' || !p[1])
+			continue; /* bash allows "command command command [-OPT] BAR" */
+
+		for (;;) {
+			p++;
+			switch (*p) {
+			case '\0':
+				argv++;
+				p = *argv;
+				if (p[0] != '-' || !p[1])
+					goto after_opts;
+				continue; /* next arg is also -opts, process it too */
+			case 'v':
+			case 'V':
+				opt_vV = *p;
+				continue;
+			default:
+				bb_error_msg_and_die("%s: %s: invalid option", "command", argv[0]);
+			}
+		}
+	}
+ after_opts:
+# if ENABLE_HUSH_FUNCTIONS
+	if (opt_vV && find_function(argv[0]))
+		if_command_vV_print_and_exit(opt_vV, argv[0], "a function");
+# endif
+#endif
+
+	/* Check if the command matches any of the builtins.
+	 * Depending on context, this might be redundant.  But it's
+	 * easier to waste a few CPU cycles than it is to figure out
+	 * if this is one of those cases.
+	 */
+	/* Why "BB_MMU ? :" difference in logic? -
+	 * On NOMMU, it is more expensive to re-execute shell
+	 * just in order to run echo or test builtin.
+	 * It's better to skip it here and run corresponding
+	 * non-builtin later. */
+	x = BB_MMU ? find_builtin(argv[0]) : find_builtin1(argv[0]);
+	if (x) {
+		if_command_vV_print_and_exit(opt_vV, argv[0], "a shell builtin");
+		exec_builtin(&nommu_save->argv_from_re_execing, x, argv);
+	}
+
+#if ENABLE_FEATURE_SH_STANDALONE
+	/* Check if the command matches any busybox applets */
+	{
+		int a = find_applet_by_name(argv[0]);
+		if (a >= 0) {
+			if_command_vV_print_and_exit(opt_vV, argv[0], "an applet");
+# if BB_MMU /* see above why on NOMMU it is not allowed */
+			if (APPLET_IS_NOEXEC(a)) {
+				/* Do not leak open fds from opened script files etc.
+				 * Testcase: interactive "ls -l /proc/self/fd"
+				 * should not show tty fd open.
+				 */
+				close_saved_fds_and_FILE_fds();
+//FIXME: should also close saved redir fds
+//This casuses test failures in
+//redir_children_should_not_see_saved_fd_2.tests
+//redir_children_should_not_see_saved_fd_3.tests
+//if you replace "busybox find" with just "find" in them
+				/* Without this, "rm -i FILE" can't be ^C'ed: */
+				switch_off_special_sigs(G.special_sig_mask);
+				debug_printf_exec("running applet '%s'\n", argv[0]);
+				run_noexec_applet_and_exit(a, argv[0], argv);
+			}
+# endif
+			/* Re-exec ourselves */
+			debug_printf_exec("re-execing applet '%s'\n", argv[0]);
+			/* Don't propagate SIG_IGN to the child */
+			if (SPECIAL_JOBSTOP_SIGS != 0)
+				switch_off_special_sigs(G.special_sig_mask & SPECIAL_JOBSTOP_SIGS);
+			execv(bb_busybox_exec_path, argv);
+			/* If they called chroot or otherwise made the binary no longer
+			 * executable, fall through */
+		}
+	}
+#endif
+
+#if ENABLE_FEATURE_SH_STANDALONE || BB_MMU
+ skip:
+#endif
+	if_command_vV_print_and_exit(opt_vV, argv[0], NULL);
+	execvp_or_die(argv);
+}
+
+/* Called after [v]fork() in run_pipe
+ */
+static void pseudo_exec(nommu_save_t *nommu_save,
+		struct command *command,
+		char **argv_expanded) NORETURN;
+static void pseudo_exec(nommu_save_t *nommu_save,
+		struct command *command,
+		char **argv_expanded)
+{
+#if ENABLE_HUSH_FUNCTIONS
+	if (command->cmd_type == CMD_FUNCDEF) {
+		/* Ignore funcdefs in pipes:
+		 * true | f() { cmd }
+		 */
+		_exit(0);
+	}
+#endif
+
+	if (command->argv) {
+		pseudo_exec_argv(nommu_save, command->argv,
+				command->assignment_cnt, argv_expanded);
+	}
+
+	if (command->group) {
+		/* Cases when we are here:
+		 * ( list )
+		 * { list } &
+		 * ... | ( list ) | ...
+		 * ... | { list } | ...
+		 */
+#if BB_MMU
+		int rcode;
+		debug_printf_exec("pseudo_exec: run_list\n");
+		reset_traps_to_defaults();
+		rcode = run_list(command->group);
+		/* OK to leak memory by not calling free_pipe_list,
+		 * since this process is about to exit */
+		_exit(rcode);
+#else
+		re_execute_shell(&nommu_save->argv_from_re_execing,
+				command->group_as_string,
+				G.global_argv[0],
+				G.global_argv + 1,
+				NULL);
+#endif
+	}
+
+	/* Case when we are here: ... | >file */
+	debug_printf_exec("pseudo_exec'ed null command\n");
+	_exit(EXIT_SUCCESS);
+}
+
+#if ENABLE_HUSH_JOB
+static const char *get_cmdtext(struct pipe *pi)
+{
+	char **argv;
+	char *p;
+	int len;
+
+	/* This is subtle. ->cmdtext is created only on first backgrounding.
+	 * (Think "cat, <ctrl-z>, fg, <ctrl-z>, fg, <ctrl-z>...." here...)
+	 * On subsequent bg argv is trashed, but we won't use it */
+	if (pi->cmdtext)
+		return pi->cmdtext;
+
+	argv = pi->cmds[0].argv;
+	if (!argv) {
+		pi->cmdtext = xzalloc(1);
+		return pi->cmdtext;
+	}
+	len = 0;
+	do {
+		len += strlen(*argv) + 1;
+	} while (*++argv);
+	p = xmalloc(len);
+	pi->cmdtext = p;
+	argv = pi->cmds[0].argv;
+	do {
+		p = stpcpy(p, *argv);
+		*p++ = ' ';
+	} while (*++argv);
+	p[-1] = '\0';
+	return pi->cmdtext;
+}
+
+static void remove_job_from_table(struct pipe *pi)
+{
+	struct pipe *prev_pipe;
+
+	if (pi == G.job_list) {
+		G.job_list = pi->next;
+	} else {
+		prev_pipe = G.job_list;
+		while (prev_pipe->next != pi)
+			prev_pipe = prev_pipe->next;
+		prev_pipe->next = pi->next;
+	}
+	G.last_jobid = 0;
+	if (G.job_list)
+		G.last_jobid = G.job_list->jobid;
+}
+
+static void delete_finished_job(struct pipe *pi)
+{
+	remove_job_from_table(pi);
+	free_pipe(pi);
+}
+
+static void clean_up_last_dead_job(void)
+{
+	if (G.job_list && !G.job_list->alive_cmds)
+		delete_finished_job(G.job_list);
+}
+
+static void insert_job_into_table(struct pipe *pi)
+{
+	struct pipe *job, **jobp;
+	int i;
+
+	clean_up_last_dead_job();
+
+	/* Find the end of the list, and find next job ID to use */
+	i = 0;
+	jobp = &G.job_list;
+	while ((job = *jobp) != NULL) {
+		if (job->jobid > i)
+			i = job->jobid;
+		jobp = &job->next;
+	}
+	pi->jobid = i + 1;
+
+	/* Create a new job struct at the end */
+	job = *jobp = xmemdup(pi, sizeof(*pi));
+	job->next = NULL;
+	job->cmds = xzalloc(sizeof(pi->cmds[0]) * pi->num_cmds);
+	/* Cannot copy entire pi->cmds[] vector! This causes double frees */
+	for (i = 0; i < pi->num_cmds; i++) {
+		job->cmds[i].pid = pi->cmds[i].pid;
+		/* all other fields are not used and stay zero */
+	}
+	job->cmdtext = xstrdup(get_cmdtext(pi));
+
+	if (G_interactive_fd)
+		printf("[%u] %u %s\n", job->jobid, (unsigned)job->cmds[0].pid, job->cmdtext);
+	G.last_jobid = job->jobid;
+}
+#endif /* JOB */
+
+static int job_exited_or_stopped(struct pipe *pi)
+{
+	int rcode, i;
+
+	if (pi->alive_cmds != pi->stopped_cmds)
+		return -1;
+
+	/* All processes in fg pipe have exited or stopped */
+	rcode = 0;
+	i = pi->num_cmds;
+	while (--i >= 0) {
+		rcode = pi->cmds[i].cmd_exitcode;
+		/* usually last process gives overall exitstatus,
+		 * but with "set -o pipefail", last *failed* process does */
+		if (G.o_opt[OPT_O_PIPEFAIL] == 0 || rcode != 0)
+			break;
+	}
+	IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
+	return rcode;
+}
+
+static int process_wait_result(struct pipe *fg_pipe, pid_t childpid, int status)
+{
+#if ENABLE_HUSH_JOB
+	struct pipe *pi;
+#endif
+	int i, dead;
+
+	dead = WIFEXITED(status) || WIFSIGNALED(status);
+
+#if DEBUG_JOBS
+	if (WIFSTOPPED(status))
+		debug_printf_jobs("pid %d stopped by sig %d (exitcode %d)\n",
+				childpid, WSTOPSIG(status), WEXITSTATUS(status));
+	if (WIFSIGNALED(status))
+		debug_printf_jobs("pid %d killed by sig %d (exitcode %d)\n",
+				childpid, WTERMSIG(status), WEXITSTATUS(status));
+	if (WIFEXITED(status))
+		debug_printf_jobs("pid %d exited, exitcode %d\n",
+				childpid, WEXITSTATUS(status));
+#endif
+	/* Were we asked to wait for a fg pipe? */
+	if (fg_pipe) {
+		i = fg_pipe->num_cmds;
+
+		while (--i >= 0) {
+			int rcode;
+
+			debug_printf_jobs("check pid %d\n", fg_pipe->cmds[i].pid);
+			if (fg_pipe->cmds[i].pid != childpid)
+				continue;
+			if (dead) {
+				int ex;
+				fg_pipe->cmds[i].pid = 0;
+				fg_pipe->alive_cmds--;
+				ex = WEXITSTATUS(status);
+				/* bash prints killer signal's name for *last*
+				 * process in pipe (prints just newline for SIGINT/SIGPIPE).
+				 * Mimic this. Example: "sleep 5" + (^\ or kill -QUIT)
+				 */
+				if (WIFSIGNALED(status)) {
+					int sig = WTERMSIG(status);
+#if ENABLE_HUSH_JOB
+					if (G.run_list_level == 1
+					/* ^^^^^ Do not print in nested contexts, example:
+					 * echo `sleep 1; sh -c 'kill -9 $$'` - prints "137", NOT "Killed 137"
+					 */
+					 && i == fg_pipe->num_cmds-1
+					) {
+						/* strsignal() is for bash compat. ~600 bloat versus bbox's get_signame() */
+						puts(sig == SIGINT || sig == SIGPIPE ? "" : strsignal(sig));
+					}
+#endif
+					/* TODO: if (WCOREDUMP(status)) + " (core dumped)"; */
+					/* MIPS has 128 sigs (1..128), if sig==128,
+					 * 128 + sig would result in exitcode 256 -> 0!
+					 */
+					ex = 128 | sig;
+				}
+				fg_pipe->cmds[i].cmd_exitcode = ex;
+			} else {
+				fg_pipe->stopped_cmds++;
+			}
+			debug_printf_jobs("fg_pipe: alive_cmds %d stopped_cmds %d\n",
+					fg_pipe->alive_cmds, fg_pipe->stopped_cmds);
+			rcode = job_exited_or_stopped(fg_pipe);
+			if (rcode >= 0) {
+/* Note: *non-interactive* bash does not continue if all processes in fg pipe
+ * are stopped. Testcase: "cat | cat" in a script (not on command line!)
+ * and "killall -STOP cat" */
+				if (G_interactive_fd) {
+#if ENABLE_HUSH_JOB
+					if (fg_pipe->alive_cmds != 0)
+						insert_job_into_table(fg_pipe);
+#endif
+					return rcode;
+				}
+				if (fg_pipe->alive_cmds == 0)
+					return rcode;
+			}
+			/* There are still running processes in the fg_pipe */
+			return -1;
+		}
+		/* It wasn't in fg_pipe, look for process in bg pipes */
+	}
+
+#if ENABLE_HUSH_JOB
+	/* We were asked to wait for bg or orphaned children */
+	/* No need to remember exitcode in this case */
+	for (pi = G.job_list; pi; pi = pi->next) {
+		for (i = 0; i < pi->num_cmds; i++) {
+			if (pi->cmds[i].pid == childpid)
+				goto found_pi_and_prognum;
+		}
+	}
+	/* Happens when shell is used as init process (init=/bin/sh) */
+	debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
+	return -1; /* this wasn't a process from fg_pipe */
+
+ found_pi_and_prognum:
+	if (dead) {
+		/* child exited */
+		int rcode = WEXITSTATUS(status);
+		if (WIFSIGNALED(status))
+			/* NB: not 128 + sig, MIPS has sig 128 */
+			rcode = 128 | WTERMSIG(status);
+		pi->cmds[i].cmd_exitcode = rcode;
+		if (G.last_bg_pid == pi->cmds[i].pid)
+			G.last_bg_pid_exitcode = rcode;
+		pi->cmds[i].pid = 0;
+		pi->alive_cmds--;
+		if (!pi->alive_cmds) {
+# if ENABLE_HUSH_BASH_COMPAT
+			G.dead_job_exitcode = job_exited_or_stopped(pi);
+# endif
+			if (G_interactive_fd) {
+				printf(JOB_STATUS_FORMAT, pi->jobid,
+						"Done", pi->cmdtext);
+				delete_finished_job(pi);
+			} else {
+/*
+ * bash deletes finished jobs from job table only in interactive mode,
+ * after "jobs" cmd, or if pid of a new process matches one of the old ones
+ * (see cleanup_dead_jobs(), delete_old_job(), J_NOTIFIED in bash source).
+ * Testcase script: "(exit 3) & sleep 1; wait %1; echo $?" prints 3 in bash.
+ * We only retain one "dead" job, if it's the single job on the list.
+ * This covers most of real-world scenarios where this is useful.
+ */
+				if (pi != G.job_list)
+					delete_finished_job(pi);
+			}
+		}
+	} else {
+		/* child stopped */
+		pi->stopped_cmds++;
+	}
+#endif
+	return -1; /* this wasn't a process from fg_pipe */
+}
+
+/* Check to see if any processes have exited -- if they have,
+ * figure out why and see if a job has completed.
+ *
+ * If non-NULL fg_pipe: wait for its completion or stop.
+ * Return its exitcode or zero if stopped.
+ *
+ * Alternatively (fg_pipe == NULL, waitfor_pid != 0):
+ * waitpid(WNOHANG), if waitfor_pid exits or stops, return exitcode+1,
+ * else return <0 if waitpid errors out (e.g. ECHILD: nothing to wait for)
+ * or 0 if no children changed status.
+ *
+ * Alternatively (fg_pipe == NULL, waitfor_pid == 0),
+ * return <0 if waitpid errors out (e.g. ECHILD: nothing to wait for)
+ * or 0 if no children changed status.
+ */
+static int checkjobs(struct pipe *fg_pipe, pid_t waitfor_pid)
+{
+	int attributes;
+	int status;
+	int rcode = 0;
+
+	debug_printf_jobs("checkjobs %p\n", fg_pipe);
+
+	attributes = WUNTRACED;
+	if (fg_pipe == NULL)
+		attributes |= WNOHANG;
+
+	errno = 0;
+#if ENABLE_HUSH_FAST
+	if (G.handled_SIGCHLD == G.count_SIGCHLD) {
+//bb_error_msg("[%d] checkjobs: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d children?:%d fg_pipe:%p",
+//getpid(), G.count_SIGCHLD, G.handled_SIGCHLD, G.we_have_children, fg_pipe);
+		/* There was neither fork nor SIGCHLD since last waitpid */
+		/* Avoid doing waitpid syscall if possible */
+		if (!G.we_have_children) {
+			errno = ECHILD;
+			return -1;
+		}
+		if (fg_pipe == NULL) { /* is WNOHANG set? */
+			/* We have children, but they did not exit
+			 * or stop yet (we saw no SIGCHLD) */
+			return 0;
+		}
+		/* else: !WNOHANG, waitpid will block, can't short-circuit */
+	}
+#endif
+
+/* Do we do this right?
+ * bash-3.00# sleep 20 | false
+ * <ctrl-Z pressed>
+ * [3]+  Stopped          sleep 20 | false
+ * bash-3.00# echo $?
+ * 1   <========== bg pipe is not fully done, but exitcode is already known!
+ * [hush 1.14.0: yes we do it right]
+ */
+	while (1) {
+		pid_t childpid;
+#if ENABLE_HUSH_FAST
+		int i;
+		i = G.count_SIGCHLD;
+#endif
+		childpid = waitpid(-1, &status, attributes);
+		if (childpid <= 0) {
+			if (childpid && errno != ECHILD)
+				bb_simple_perror_msg("waitpid");
+#if ENABLE_HUSH_FAST
+			else { /* Until next SIGCHLD, waitpid's are useless */
+				G.we_have_children = (childpid == 0);
+				G.handled_SIGCHLD = i;
+//bb_error_msg("[%d] checkjobs: waitpid returned <= 0, G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD);
+			}
+#endif
+			/* ECHILD (no children), or 0 (no change in children status) */
+			rcode = childpid;
+			break;
+		}
+		rcode = process_wait_result(fg_pipe, childpid, status);
+		if (rcode >= 0) {
+			/* fg_pipe exited or stopped */
+			break;
+		}
+		if (childpid == waitfor_pid) { /* "wait PID" */
+			debug_printf_exec("childpid==waitfor_pid:%d status:0x%08x\n", childpid, status);
+			rcode = WEXITSTATUS(status);
+			if (WIFSIGNALED(status))
+				rcode = 128 | WTERMSIG(status);
+			if (WIFSTOPPED(status))
+				/* bash: "cmd & wait $!" and cmd stops: $? = 128 | stopsig */
+				rcode = 128 | WSTOPSIG(status);
+			rcode++;
+			break; /* "wait PID" called us, give it exitcode+1 */
+		}
+#if ENABLE_HUSH_BASH_COMPAT
+		if (-1 == waitfor_pid /* "wait -n" (wait for any one job) */
+		 && G.dead_job_exitcode >= 0 /* some job did finish */
+		) {
+			debug_printf_exec("waitfor_pid:-1\n");
+			rcode = G.dead_job_exitcode + 1;
+			break;
+		}
+#endif
+		/* This wasn't one of our processes, or */
+		/* fg_pipe still has running processes, do waitpid again */
+	} /* while (waitpid succeeds)... */
+
+	return rcode;
+}
+
+#if ENABLE_HUSH_JOB
+static int checkjobs_and_fg_shell(struct pipe *fg_pipe)
+{
+	pid_t p;
+	int rcode = checkjobs(fg_pipe, 0 /*(no pid to wait for)*/);
+	if (G_saved_tty_pgrp) {
+		/* Job finished, move the shell to the foreground */
+		p = getpgrp(); /* our process group id */
+		debug_printf_jobs("fg'ing ourself: getpgrp()=%d\n", (int)p);
+		tcsetpgrp(G_interactive_fd, p);
+	}
+	return rcode;
+}
+#endif
+
+/* Start all the jobs, but don't wait for anything to finish.
+ * See checkjobs().
+ *
+ * Return code is normally -1, when the caller has to wait for children
+ * to finish to determine the exit status of the pipe.  If the pipe
+ * is a simple builtin command, however, the action is done by the
+ * time run_pipe returns, and the exit code is provided as the
+ * return value.
+ *
+ * Returns -1 only if started some children. IOW: we have to
+ * mask out retvals of builtins etc with 0xff!
+ *
+ * The only case when we do not need to [v]fork is when the pipe
+ * is single, non-backgrounded, non-subshell command. Examples:
+ * cmd ; ...   { list } ; ...
+ * cmd && ...  { list } && ...
+ * cmd || ...  { list } || ...
+ * If it is, then we can run cmd as a builtin, NOFORK,
+ * or (if SH_STANDALONE) an applet, and we can run the { list }
+ * with run_list. If it isn't one of these, we fork and exec cmd.
+ *
+ * Cases when we must fork:
+ * non-single:   cmd | cmd
+ * backgrounded: cmd &     { list } &
+ * subshell:     ( list ) [&]
+ */
+#if !ENABLE_HUSH_MODE_X
+#define redirect_and_varexp_helper(command, sqp, argv_expanded) \
+	redirect_and_varexp_helper(command, sqp)
+#endif
+static int redirect_and_varexp_helper(
+		struct command *command,
+		struct squirrel **sqp,
+		char **argv_expanded)
+{
+	/* Assignments occur before redirects. Try:
+	 * a=`sleep 1` sleep 2 3>/qwe/rty
+	 */
+
+	char **new_env = expand_assignments(command->argv, command->assignment_cnt);
+	dump_cmd_in_x_mode(new_env);
+	dump_cmd_in_x_mode(argv_expanded);
+	/* this takes ownership of new_env[i] elements, and frees new_env: */
+	set_vars_and_save_old(new_env);
+
+	return setup_redirects(command, sqp);
+}
+static NOINLINE int run_pipe(struct pipe *pi)
+{
+	static const char *const null_ptr = NULL;
+
+	int cmd_no;
+	int next_infd;
+	struct command *command;
+	char **argv_expanded;
+	char **argv;
+	struct squirrel *squirrel = NULL;
+	int rcode;
+
+	debug_printf_exec("run_pipe start: members:%d\n", pi->num_cmds);
+	debug_enter();
+
+	/* Testcase: set -- q w e; (IFS='' echo "$*"; IFS=''; echo "$*"); echo "$*"
+	 * Result should be 3 lines: q w e, qwe, q w e
+	 */
+	if (G.ifs_whitespace != G.ifs)
+		free(G.ifs_whitespace);
+	G.ifs = get_local_var_value("IFS");
+	if (G.ifs) {
+		char *p;
+		G.ifs_whitespace = (char*)G.ifs;
+		p = skip_whitespace(G.ifs);
+		if (*p) {
+			/* Not all $IFS is whitespace */
+			char *d;
+			int len = p - G.ifs;
+			p = skip_non_whitespace(p);
+			G.ifs_whitespace = xmalloc(len + strlen(p) + 1); /* can overestimate */
+			d = mempcpy(G.ifs_whitespace, G.ifs, len);
+			while (*p) {
+				if (isspace(*p))
+					*d++ = *p;
+				p++;
+			}
+			*d = '\0';
+		}
+	} else {
+		G.ifs = defifs;
+		G.ifs_whitespace = (char*)G.ifs;
+	}
+
+	IF_HUSH_JOB(pi->pgrp = -1;)
+	pi->stopped_cmds = 0;
+	command = &pi->cmds[0];
+	argv_expanded = NULL;
+
+	if (pi->num_cmds != 1
+	 || pi->followup == PIPE_BG
+	 || command->cmd_type == CMD_SUBSHELL
+	) {
+		goto must_fork;
+	}
+
+	pi->alive_cmds = 1;
+
+	debug_printf_exec(": group:%p argv:'%s'\n",
+		command->group, command->argv ? command->argv[0] : "NONE");
+
+	if (command->group) {
+#if ENABLE_HUSH_FUNCTIONS
+		if (command->cmd_type == CMD_FUNCDEF) {
+			/* "executing" func () { list } */
+			struct function *funcp;
+
+			funcp = new_function(command->argv[0]);
+			/* funcp->name is already set to argv[0] */
+			funcp->body = command->group;
+# if !BB_MMU
+			funcp->body_as_string = command->group_as_string;
+			command->group_as_string = NULL;
+# endif
+			command->group = NULL;
+			command->argv[0] = NULL;
+			debug_printf_exec("cmd %p has child func at %p\n", command, funcp);
+			funcp->parent_cmd = command;
+			command->child_func = funcp;
+
+			debug_printf_exec("run_pipe: return EXIT_SUCCESS\n");
+			debug_leave();
+			return EXIT_SUCCESS;
+		}
+#endif
+		/* { list } */
+		debug_printf_exec("non-subshell group\n");
+		rcode = 1; /* exitcode if redir failed */
+		if (setup_redirects(command, &squirrel) == 0) {
+			debug_printf_exec(": run_list\n");
+//FIXME: we need to pass squirrel down into run_list()
+//for SH_STANDALONE case, or else this construct:
+// { find /proc/self/fd; true; } >FILE; cmd2
+//has no way of closing saved fd#1 for "find",
+//and in SH_STANDALONE mode, "find" is not execed,
+//therefore CLOEXEC on saved fd does not help.
+			rcode = run_list(command->group) & 0xff;
+		}
+		restore_redirects(squirrel);
+		IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
+		debug_leave();
+		debug_printf_exec("run_pipe: return %d\n", rcode);
+		return rcode;
+	}
+
+	argv = command->argv ? command->argv : (char **) &null_ptr;
+	{
+		const struct built_in_command *x;
+		IF_HUSH_FUNCTIONS(const struct function *funcp;)
+		IF_NOT_HUSH_FUNCTIONS(enum { funcp = 0 };)
+		struct variable **sv_shadowed;
+		struct variable *old_vars;
+
+#if ENABLE_HUSH_LINENO_VAR
+		G.execute_lineno = command->lineno;
+#endif
+
+		if (argv[command->assignment_cnt] == NULL) {
+			/* Assignments, but no command.
+			 * Ensure redirects take effect (that is, create files).
+			 * Try "a=t >file"
+			 */
+			unsigned i;
+			G.expand_exitcode = 0;
+ only_assignments:
+			rcode = setup_redirects(command, &squirrel);
+			restore_redirects(squirrel);
+
+			/* Set shell variables */
+			i = 0;
+			while (i < command->assignment_cnt) {
+				char *p = expand_string_to_string(argv[i],
+						EXP_FLAG_ESC_GLOB_CHARS,
+						/*unbackslash:*/ 1
+				);
+#if ENABLE_HUSH_MODE_X
+				if (G_x_mode) {
+					char *eq;
+					if (i == 0)
+						x_mode_prefix();
+					x_mode_addchr(' ');
+					eq = strchrnul(p, '=');
+					if (*eq) eq++;
+					x_mode_addblock(p, (eq - p));
+					x_mode_print_optionally_squoted(eq);
+					x_mode_flush();
+				}
+#endif
+				debug_printf_env("set shell var:'%s'->'%s'\n", *argv, p);
+				if (set_local_var(p, /*flag:*/ 0)) {
+					/* assignment to readonly var / putenv error? */
+					rcode = 1;
+				}
+				i++;
+			}
+			/* Redirect error sets $? to 1. Otherwise,
+			 * if evaluating assignment value set $?, retain it.
+			 * Else, clear $?:
+			 *  false; q=`exit 2`; echo $? - should print 2
+			 *  false; x=1; echo $? - should print 0
+			 * Because of the 2nd case, we can't just use G.last_exitcode.
+			 */
+			if (rcode == 0)
+				rcode = G.expand_exitcode;
+			IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
+			debug_leave();
+			debug_printf_exec("run_pipe: return %d\n", rcode);
+			return rcode;
+		}
+
+		/* Expand the rest into (possibly) many strings each */
+#if defined(CMD_TEST2_SINGLEWORD_NOGLOB)
+		if (command->cmd_type == CMD_TEST2_SINGLEWORD_NOGLOB)
+			argv_expanded = expand_strvec_to_strvec_singleword_noglob(argv + command->assignment_cnt);
+		else
+#endif
+#if defined(CMD_SINGLEWORD_NOGLOB)
+		if (command->cmd_type == CMD_SINGLEWORD_NOGLOB)
+			argv_expanded = expand_strvec_to_strvec_singleword_noglob(argv + command->assignment_cnt);
+		else
+#endif
+			argv_expanded = expand_strvec_to_strvec(argv + command->assignment_cnt);
+
+		/* If someone gives us an empty string: `cmd with empty output` */
+		if (!argv_expanded[0]) {
+			free(argv_expanded);
+			/* `false` still has to set exitcode 1 */
+			G.expand_exitcode = G.last_exitcode;
+			goto only_assignments;
+		}
+
+		old_vars = NULL;
+		sv_shadowed = G.shadowed_vars_pp;
+
+		/* Check if argv[0] matches any functions (this goes before bltins) */
+		IF_HUSH_FUNCTIONS(funcp = find_function(argv_expanded[0]);)
+		IF_HUSH_FUNCTIONS(x = NULL;)
+		IF_HUSH_FUNCTIONS(if (!funcp))
+			x = find_builtin(argv_expanded[0]);
+		if (x || funcp) {
+			if (x && x->b_function == builtin_exec && argv_expanded[1] == NULL) {
+				debug_printf("exec with redirects only\n");
+				/*
+				 * Variable assignments are executed, but then "forgotten":
+				 *  a=`sleep 1;echo A` exec 3>&-; echo $a
+				 * sleeps, but prints nothing.
+				 */
+				enter_var_nest_level();
+				G.shadowed_vars_pp = &old_vars;
+				rcode = redirect_and_varexp_helper(command,
+					/*squirrel:*/ ERR_PTR,
+					argv_expanded
+				);
+				G.shadowed_vars_pp = sv_shadowed;
+				/* rcode=1 can be if redir file can't be opened */
+
+				goto clean_up_and_ret1;
+			}
+
+			/* Bump var nesting, or this will leak exported $a:
+			 * a=b true; env | grep ^a=
+			 */
+			enter_var_nest_level();
+			/* Collect all variables "shadowed" by helper
+			 * (IOW: old vars overridden by "var1=val1 var2=val2 cmd..." syntax)
+			 * into old_vars list:
+			 */
+			G.shadowed_vars_pp = &old_vars;
+			rcode = redirect_and_varexp_helper(command, &squirrel, argv_expanded);
+			if (rcode == 0) {
+				if (!funcp) {
+					/* Do not collect *to old_vars list* vars shadowed
+					 * by e.g. "local VAR" builtin (collect them
+					 * in the previously nested list instead):
+					 * don't want them to be restored immediately
+					 * after "local" completes.
+					 */
+					G.shadowed_vars_pp = sv_shadowed;
+
+					debug_printf_exec(": builtin '%s' '%s'...\n",
+						x->b_cmd, argv_expanded[1]);
+					fflush_all();
+					rcode = x->b_function(argv_expanded) & 0xff;
+					fflush_all();
+				}
+#if ENABLE_HUSH_FUNCTIONS
+				else {
+					debug_printf_exec(": function '%s' '%s'...\n",
+						funcp->name, argv_expanded[1]);
+					rcode = run_function(funcp, argv_expanded) & 0xff;
+					/*
+					 * But do collect *to old_vars list* vars shadowed
+					 * within function execution. To that end, restore
+					 * this pointer _after_ function run:
+					 */
+					G.shadowed_vars_pp = sv_shadowed;
+				}
+#endif
+			}
+		} else
+		if (ENABLE_FEATURE_SH_NOFORK && NUM_APPLETS > 1) {
+			int n = find_applet_by_name(argv_expanded[0]);
+			if (n < 0 || !APPLET_IS_NOFORK(n))
+				goto must_fork;
+
+			enter_var_nest_level();
+			/* Collect all variables "shadowed" by helper into old_vars list */
+			G.shadowed_vars_pp = &old_vars;
+			rcode = redirect_and_varexp_helper(command, &squirrel, argv_expanded);
+			G.shadowed_vars_pp = sv_shadowed;
+
+			if (rcode == 0) {
+				debug_printf_exec(": run_nofork_applet '%s' '%s'...\n",
+					argv_expanded[0], argv_expanded[1]);
+				/*
+				 * Note: signals (^C) can't interrupt here.
+				 * We remember them and they will be acted upon
+				 * after applet returns.
+				 * This makes applets which can run for a long time
+				 * and/or wait for user input ineligible for NOFORK:
+				 * for example, "yes" or "rm" (rm -i waits for input).
+				 */
+				rcode = run_nofork_applet(n, argv_expanded);
+			}
+		} else
+			goto must_fork;
+
+		restore_redirects(squirrel);
+ clean_up_and_ret1:
+		leave_var_nest_level();
+		add_vars(old_vars);
+
+		/*
+		 * Try "usleep 99999999" + ^C + "echo $?"
+		 * with FEATURE_SH_NOFORK=y.
+		 */
+		if (!funcp) {
+			/* It was builtin or nofork.
+			 * if this would be a real fork/execed program,
+			 * it should have died if a fatal sig was received.
+			 * But OTOH, there was no separate process,
+			 * the sig was sent to _shell_, not to non-existing
+			 * child.
+			 * Let's just handle ^C only, this one is obvious:
+			 * we aren't ok with exitcode 0 when ^C was pressed
+			 * during builtin/nofork.
+			 */
+			if (sigismember(&G.pending_set, SIGINT))
+				rcode = 128 | SIGINT;
+		}
+		free(argv_expanded);
+		IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
+		debug_leave();
+		debug_printf_exec("run_pipe return %d\n", rcode);
+		return rcode;
+	}
+
+ must_fork:
+	/* NB: argv_expanded may already be created, and that
+	 * might include `cmd` runs! Do not rerun it! We *must*
+	 * use argv_expanded if it's non-NULL */
+
+	/* Going to fork a child per each pipe member */
+	pi->alive_cmds = 0;
+	next_infd = 0;
+
+	cmd_no = 0;
+	while (cmd_no < pi->num_cmds) {
+		struct fd_pair pipefds;
+#if !BB_MMU
+		int sv_var_nest_level = G.var_nest_level;
+		volatile nommu_save_t nommu_save;
+		nommu_save.old_vars = NULL;
+		nommu_save.argv = NULL;
+		nommu_save.argv_from_re_execing = NULL;
+#endif
+		command = &pi->cmds[cmd_no];
+		cmd_no++;
+		if (command->argv) {
+			debug_printf_exec(": pipe member '%s' '%s'...\n",
+					command->argv[0], command->argv[1]);
+		} else {
+			debug_printf_exec(": pipe member with no argv\n");
+		}
+
+		/* pipes are inserted between pairs of commands */
+		pipefds.rd = 0;
+		pipefds.wr = 1;
+		if (cmd_no < pi->num_cmds)
+			xpiped_pair(pipefds);
+
+#if ENABLE_HUSH_LINENO_VAR
+		G.execute_lineno = command->lineno;
+#endif
+
+		command->pid = BB_MMU ? fork() : vfork();
+		if (!command->pid) { /* child */
+#if ENABLE_HUSH_JOB
+			disable_restore_tty_pgrp_on_exit();
+			CLEAR_RANDOM_T(&G.random_gen); /* or else $RANDOM repeats in child */
+
+			/* Every child adds itself to new process group
+			 * with pgid == pid_of_first_child_in_pipe */
+			if (G.run_list_level == 1 && G_interactive_fd) {
+				pid_t pgrp;
+				pgrp = pi->pgrp;
+				if (pgrp < 0) /* true for 1st process only */
+					pgrp = getpid();
+				if (setpgid(0, pgrp) == 0
+				 && pi->followup != PIPE_BG
+				 && G_saved_tty_pgrp /* we have ctty */
+				) {
+					/* We do it in *every* child, not just first,
+					 * to avoid races */
+					tcsetpgrp(G_interactive_fd, pgrp);
+				}
+			}
+#endif
+			if (pi->alive_cmds == 0 && pi->followup == PIPE_BG) {
+				/* 1st cmd in backgrounded pipe
+				 * should have its stdin /dev/null'ed */
+				close(0);
+				if (open(bb_dev_null, O_RDONLY))
+					xopen("/", O_RDONLY);
+			} else {
+				xmove_fd(next_infd, 0);
+			}
+			xmove_fd(pipefds.wr, 1);
+			if (pipefds.rd > 1)
+				close(pipefds.rd);
+			/* Like bash, explicit redirects override pipes,
+			 * and the pipe fd (fd#1) is available for dup'ing:
+			 * "cmd1 2>&1 | cmd2": fd#1 is duped to fd#2, thus stderr
+			 * of cmd1 goes into pipe.
+			 */
+			if (setup_redirects(command, NULL)) {
+				/* Happens when redir file can't be opened:
+				 * $ hush -c 'echo FOO >&2 | echo BAR 3>/qwe/rty; echo BAZ'
+				 * FOO
+				 * hush: can't open '/qwe/rty': No such file or directory
+				 * BAZ
+				 * (echo BAR is not executed, it hits _exit(1) below)
+				 */
+				_exit(1);
+			}
+
+			/* Stores to nommu_save list of env vars putenv'ed
+			 * (NOMMU, on MMU we don't need that) */
+			/* cast away volatility... */
+			pseudo_exec((nommu_save_t*) &nommu_save, command, argv_expanded);
+			/* pseudo_exec() does not return */
+		}
+
+		/* parent or error */
+#if ENABLE_HUSH_FAST
+		G.count_SIGCHLD++;
+//bb_error_msg("[%d] fork in run_pipe: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD);
+#endif
+		enable_restore_tty_pgrp_on_exit();
+#if !BB_MMU
+		/* Clean up after vforked child */
+		free(nommu_save.argv);
+		free(nommu_save.argv_from_re_execing);
+		G.var_nest_level = sv_var_nest_level;
+		remove_nested_vars();
+		add_vars(nommu_save.old_vars);
+#endif
+		free(argv_expanded);
+		argv_expanded = NULL;
+		if (command->pid < 0) { /* [v]fork failed */
+			/* Clearly indicate, was it fork or vfork */
+			bb_simple_perror_msg(BB_MMU ? "vfork"+1 : "vfork");
+		} else {
+			pi->alive_cmds++;
+#if ENABLE_HUSH_JOB
+			/* Second and next children need to know pid of first one */
+			if (pi->pgrp < 0)
+				pi->pgrp = command->pid;
+#endif
+		}
+
+		if (cmd_no > 1)
+			close(next_infd);
+		if (cmd_no < pi->num_cmds)
+			close(pipefds.wr);
+		/* Pass read (output) pipe end to next iteration */
+		next_infd = pipefds.rd;
+	}
+
+	if (!pi->alive_cmds) {
+		debug_leave();
+		debug_printf_exec("run_pipe return 1 (all forks failed, no children)\n");
+		return 1;
+	}
+
+	debug_leave();
+	debug_printf_exec("run_pipe return -1 (%u children started)\n", pi->alive_cmds);
+	return -1;
+}
+
+/* NB: called by pseudo_exec, and therefore must not modify any
+ * global data until exec/_exit (we can be a child after vfork!) */
+static int run_list(struct pipe *pi)
+{
+#if ENABLE_HUSH_CASE
+	char *case_word = NULL;
+#endif
+#if ENABLE_HUSH_LOOPS
+	struct pipe *loop_top = NULL;
+	char **for_lcur = NULL;
+	char **for_list = NULL;
+#endif
+	smallint last_followup;
+	smalluint rcode;
+#if ENABLE_HUSH_IF || ENABLE_HUSH_CASE
+	smalluint cond_code = 0;
+#else
+	enum { cond_code = 0 };
+#endif
+#if HAS_KEYWORDS
+	smallint rword;      /* RES_foo */
+	smallint last_rword; /* ditto */
+#endif
+
+	debug_printf_exec("run_list start lvl %d\n", G.run_list_level);
+	debug_enter();
+
+#if ENABLE_HUSH_LOOPS
+	/* Check syntax for "for" */
+	{
+		struct pipe *cpipe;
+		for (cpipe = pi; cpipe; cpipe = cpipe->next) {
+			if (cpipe->res_word != RES_FOR && cpipe->res_word != RES_IN)
+				continue;
+			/* current word is FOR or IN (BOLD in comments below) */
+			if (cpipe->next == NULL) {
+				syntax_error("malformed for");
+				debug_leave();
+				debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
+				return 1;
+			}
+			/* "FOR v; do ..." and "for v IN a b; do..." are ok */
+			if (cpipe->next->res_word == RES_DO)
+				continue;
+			/* next word is not "do". It must be "in" then ("FOR v in ...") */
+			if (cpipe->res_word == RES_IN /* "for v IN a b; not_do..."? */
+			 || cpipe->next->res_word != RES_IN /* FOR v not_do_and_not_in..."? */
+			) {
+				syntax_error("malformed for");
+				debug_leave();
+				debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
+				return 1;
+			}
+		}
+	}
+#endif
+
+	/* Past this point, all code paths should jump to ret: label
+	 * in order to return, no direct "return" statements please.
+	 * This helps to ensure that no memory is leaked. */
+
+#if ENABLE_HUSH_JOB
+	G.run_list_level++;
+#endif
+
+#if HAS_KEYWORDS
+	rword = RES_NONE;
+	last_rword = RES_XXXX;
+#endif
+	last_followup = PIPE_SEQ;
+	rcode = G.last_exitcode;
+
+	/* Go through list of pipes, (maybe) executing them. */
+	for (; pi; pi = IF_HUSH_LOOPS(rword == RES_DONE ? loop_top : ) pi->next) {
+		int r;
+		int sv_errexit_depth;
+
+		if (G.flag_SIGINT)
+			break;
+		if (G_flag_return_in_progress == 1)
+			break;
+
+		IF_HAS_KEYWORDS(rword = pi->res_word;)
+		debug_printf_exec(": rword=%d cond_code=%d last_rword=%d\n",
+				rword, cond_code, last_rword);
+
+		sv_errexit_depth = G.errexit_depth;
+		if (
+#if ENABLE_HUSH_IF
+		    rword == RES_IF || rword == RES_ELIF ||
+#endif
+		    pi->followup != PIPE_SEQ
+		) {
+			G.errexit_depth++;
+		}
+#if ENABLE_HUSH_LOOPS
+		if ((rword == RES_WHILE || rword == RES_UNTIL || rword == RES_FOR)
+		 && loop_top == NULL /* avoid bumping G.depth_of_loop twice */
+		) {
+			/* start of a loop: remember where loop starts */
+			loop_top = pi;
+			G.depth_of_loop++;
+		}
+#endif
+		/* Still in the same "if...", "then..." or "do..." branch? */
+		if (IF_HAS_KEYWORDS(rword == last_rword &&) 1) {
+			if ((rcode == 0 && last_followup == PIPE_OR)
+			 || (rcode != 0 && last_followup == PIPE_AND)
+			) {
+				/* It is "<true> || CMD" or "<false> && CMD"
+				 * and we should not execute CMD */
+				debug_printf_exec("skipped cmd because of || or &&\n");
+				last_followup = pi->followup;
+				goto dont_check_jobs_but_continue;
+			}
+		}
+		last_followup = pi->followup;
+		IF_HAS_KEYWORDS(last_rword = rword;)
+#if ENABLE_HUSH_IF
+		if (cond_code) {
+			if (rword == RES_THEN) {
+				/* if false; then ... fi has exitcode 0! */
+				G.last_exitcode = rcode = EXIT_SUCCESS;
+				/* "if <false> THEN cmd": skip cmd */
+				continue;
+			}
+		} else {
+			if (rword == RES_ELSE || rword == RES_ELIF) {
+				/* "if <true> then ... ELSE/ELIF cmd":
+				 * skip cmd and all following ones */
+				break;
+			}
+		}
+#endif
+#if ENABLE_HUSH_LOOPS
+		if (rword == RES_FOR) { /* && pi->num_cmds - always == 1 */
+			if (!for_lcur) {
+				/* first loop through for */
+
+				static const char encoded_dollar_at[] ALIGN1 = {
+					SPECIAL_VAR_SYMBOL, '@' | 0x80, SPECIAL_VAR_SYMBOL, '\0'
+				}; /* encoded representation of "$@" */
+				static const char *const encoded_dollar_at_argv[] = {
+					encoded_dollar_at, NULL
+				}; /* argv list with one element: "$@" */
+				char **vals;
+
+				G.last_exitcode = rcode = EXIT_SUCCESS;
+				vals = (char**)encoded_dollar_at_argv;
+				if (pi->next->res_word == RES_IN) {
+					/* if no variable values after "in" we skip "for" */
+					if (!pi->next->cmds[0].argv) {
+						debug_printf_exec(": null FOR: exitcode EXIT_SUCCESS\n");
+						break;
+					}
+					vals = pi->next->cmds[0].argv;
+				} /* else: "for var; do..." -> assume "$@" list */
+				/* create list of variable values */
+				debug_print_strings("for_list made from", vals);
+				for_list = expand_strvec_to_strvec(vals);
+				for_lcur = for_list;
+				debug_print_strings("for_list", for_list);
+			}
+			if (!*for_lcur) {
+				/* "for" loop is over, clean up */
+				free(for_list);
+				for_list = NULL;
+				for_lcur = NULL;
+				break;
+			}
+			/* Insert next value from for_lcur */
+			/* note: *for_lcur already has quotes removed, $var expanded, etc */
+			set_local_var(xasprintf("%s=%s", pi->cmds[0].argv[0], *for_lcur++), /*flag:*/ 0);
+			continue;
+		}
+		if (rword == RES_IN) {
+			continue; /* "for v IN list;..." - "in" has no cmds anyway */
+		}
+		if (rword == RES_DONE) {
+			continue; /* "done" has no cmds too */
+		}
+#endif
+#if ENABLE_HUSH_CASE
+		if (rword == RES_CASE) {
+			debug_printf_exec("CASE cond_code:%d\n", cond_code);
+			case_word = expand_string_to_string(pi->cmds->argv[0],
+				EXP_FLAG_ESC_GLOB_CHARS, /*unbackslash:*/ 1);
+			debug_printf_exec("CASE word1:'%s'\n", case_word);
+			//unbackslash(case_word);
+			//debug_printf_exec("CASE word2:'%s'\n", case_word);
+			continue;
+		}
+		if (rword == RES_MATCH) {
+			char **argv;
+
+			debug_printf_exec("MATCH cond_code:%d\n", cond_code);
+			if (!case_word) /* "case ... matched_word) ... WORD)": we executed selected branch, stop */
+				break;
+			/* all prev words didn't match, does this one match? */
+			argv = pi->cmds->argv;
+			while (*argv) {
+				char *pattern;
+				debug_printf_exec("expand_string_to_string('%s')\n", *argv);
+				pattern = expand_string_to_string(*argv,
+						EXP_FLAG_ESC_GLOB_CHARS,
+						/*unbackslash:*/ 0
+				);
+				/* TODO: which FNM_xxx flags to use? */
+				cond_code = (fnmatch(pattern, case_word, /*flags:*/ 0) != 0);
+				debug_printf_exec("fnmatch(pattern:'%s',str:'%s'):%d\n",
+						pattern, case_word, cond_code);
+				free(pattern);
+				if (cond_code == 0) {
+					/* match! we will execute this branch */
+					free(case_word);
+					case_word = NULL; /* make future "word)" stop */
+					break;
+				}
+				argv++;
+			}
+			continue;
+		}
+		if (rword == RES_CASE_BODY) { /* inside of a case branch */
+			debug_printf_exec("CASE_BODY cond_code:%d\n", cond_code);
+			if (cond_code != 0)
+				continue; /* not matched yet, skip this pipe */
+		}
+		if (rword == RES_ESAC) {
+			debug_printf_exec("ESAC cond_code:%d\n", cond_code);
+			if (case_word) {
+				/* "case" did not match anything: still set $? (to 0) */
+				G.last_exitcode = rcode = EXIT_SUCCESS;
+			}
+		}
+#endif
+		/* Just pressing <enter> in shell should check for jobs.
+		 * OTOH, in non-interactive shell this is useless
+		 * and only leads to extra job checks */
+		if (pi->num_cmds == 0) {
+			if (G_interactive_fd)
+				goto check_jobs_and_continue;
+			continue;
+		}
+
+		/* After analyzing all keywords and conditions, we decided
+		 * to execute this pipe. NB: have to do checkjobs(NULL)
+		 * after run_pipe to collect any background children,
+		 * even if list execution is to be stopped. */
+		debug_printf_exec(": run_pipe with %d members\n", pi->num_cmds);
+#if ENABLE_HUSH_LOOPS
+		G.flag_break_continue = 0;
+#endif
+		rcode = r = run_pipe(pi); /* NB: rcode is a smalluint, r is int */
+		if (r != -1) {
+			/* We ran a builtin, function, or group.
+			 * rcode is already known
+			 * and we don't need to wait for anything. */
+			debug_printf_exec(": builtin/func exitcode %d\n", rcode);
+			G.last_exitcode = rcode;
+			check_and_run_traps();
+#if ENABLE_HUSH_TRAP && ENABLE_HUSH_FUNCTIONS
+			rcode = G.last_exitcode; /* "return" in trap can change it, read back */
+#endif
+#if ENABLE_HUSH_LOOPS
+			/* Was it "break" or "continue"? */
+			if (G.flag_break_continue) {
+				smallint fbc = G.flag_break_continue;
+				/* We might fall into outer *loop*,
+				 * don't want to break it too */
+				if (loop_top) {
+					G.depth_break_continue--;
+					if (G.depth_break_continue == 0)
+						G.flag_break_continue = 0;
+					/* else: e.g. "continue 2" should *break* once, *then* continue */
+				} /* else: "while... do... { we are here (innermost list is not a loop!) };...done" */
+				if (G.depth_break_continue != 0 || fbc == BC_BREAK) {
+					checkjobs(NULL, 0 /*(no pid to wait for)*/);
+					break;
+				}
+				/* "continue": simulate end of loop */
+				rword = RES_DONE;
+				continue;
+			}
+#endif
+			if (G_flag_return_in_progress == 1) {
+				checkjobs(NULL, 0 /*(no pid to wait for)*/);
+				break;
+			}
+		} else if (pi->followup == PIPE_BG) {
+			/* What does bash do with attempts to background builtins? */
+			/* even bash 3.2 doesn't do that well with nested bg:
+			 * try "{ { sleep 10; echo DEEP; } & echo HERE; } &".
+			 * I'm NOT treating inner &'s as jobs */
+#if ENABLE_HUSH_JOB
+			if (G.run_list_level == 1)
+				insert_job_into_table(pi);
+#endif
+			/* Last command's pid goes to $! */
+			G.last_bg_pid = pi->cmds[pi->num_cmds - 1].pid;
+			G.last_bg_pid_exitcode = 0;
+			debug_printf_exec(": cmd&: exitcode EXIT_SUCCESS\n");
+/* Check pi->pi_inverted? "! sleep 1 & echo $?": bash says 1. dash and ash say 0 */
+			rcode = EXIT_SUCCESS;
+			goto check_traps;
+		} else {
+#if ENABLE_HUSH_JOB
+			if (G.run_list_level == 1 && G_interactive_fd) {
+				/* Waits for completion, then fg's main shell */
+				rcode = checkjobs_and_fg_shell(pi);
+				debug_printf_exec(": checkjobs_and_fg_shell exitcode %d\n", rcode);
+				goto check_traps;
+			}
+#endif
+			/* This one just waits for completion */
+			rcode = checkjobs(pi, 0 /*(no pid to wait for)*/);
+			debug_printf_exec(": checkjobs exitcode %d\n", rcode);
+ check_traps:
+			G.last_exitcode = rcode;
+			check_and_run_traps();
+#if ENABLE_HUSH_TRAP && ENABLE_HUSH_FUNCTIONS
+			rcode = G.last_exitcode; /* "return" in trap can change it, read back */
+#endif
+		}
+
+		/* Handle "set -e" */
+		if (rcode != 0 && G.o_opt[OPT_O_ERREXIT]) {
+			debug_printf_exec("ERREXIT:1 errexit_depth:%d\n", G.errexit_depth);
+			if (G.errexit_depth == 0)
+				hush_exit(rcode);
+		}
+		G.errexit_depth = sv_errexit_depth;
+
+		/* Analyze how result affects subsequent commands */
+#if ENABLE_HUSH_IF
+		if (rword == RES_IF || rword == RES_ELIF)
+			cond_code = rcode;
+#endif
+ check_jobs_and_continue:
+		checkjobs(NULL, 0 /*(no pid to wait for)*/);
+ dont_check_jobs_but_continue: ;
+#if ENABLE_HUSH_LOOPS
+		/* Beware of "while false; true; do ..."! */
+		if (pi->next
+		 && (pi->next->res_word == RES_DO || pi->next->res_word == RES_DONE)
+		 /* check for RES_DONE is needed for "while ...; do \n done" case */
+		) {
+			if (rword == RES_WHILE) {
+				if (rcode) {
+					/* "while false; do...done" - exitcode 0 */
+					G.last_exitcode = rcode = EXIT_SUCCESS;
+					debug_printf_exec(": while expr is false: breaking (exitcode:EXIT_SUCCESS)\n");
+					break;
+				}
+			}
+			if (rword == RES_UNTIL) {
+				if (!rcode) {
+					debug_printf_exec(": until expr is true: breaking\n");
+					break;
+				}
+			}
+		}
+#endif
+	} /* for (pi) */
+
+#if ENABLE_HUSH_JOB
+	G.run_list_level--;
+#endif
+#if ENABLE_HUSH_LOOPS
+	if (loop_top)
+		G.depth_of_loop--;
+	free(for_list);
+#endif
+#if ENABLE_HUSH_CASE
+	free(case_word);
+#endif
+	debug_leave();
+	debug_printf_exec("run_list lvl %d return %d\n", G.run_list_level + 1, rcode);
+	return rcode;
+}
+
+/* Select which version we will use */
+static int run_and_free_list(struct pipe *pi)
+{
+	int rcode = 0;
+	debug_printf_exec("run_and_free_list entered\n");
+	if (!G.o_opt[OPT_O_NOEXEC]) {
+		debug_printf_exec(": run_list: 1st pipe with %d cmds\n", pi->num_cmds);
+		rcode = run_list(pi);
+	}
+	/* free_pipe_list has the side effect of clearing memory.
+	 * In the long run that function can be merged with run_list,
+	 * but doing that now would hobble the debugging effort. */
+	free_pipe_list(pi);
+	debug_printf_exec("run_and_free_list return %d\n", rcode);
+	return rcode;
+}
+
+
+static void install_sighandlers(unsigned mask)
+{
+	sighandler_t old_handler;
+	unsigned sig = 0;
+	while ((mask >>= 1) != 0) {
+		sig++;
+		if (!(mask & 1))
+			continue;
+		old_handler = install_sighandler(sig, pick_sighandler(sig));
+		/* POSIX allows shell to re-enable SIGCHLD
+		 * even if it was SIG_IGN on entry.
+		 * Therefore we skip IGN check for it:
+		 */
+		if (sig == SIGCHLD)
+			continue;
+		/* Interactive bash re-enables SIGHUP which is SIG_IGNed on entry.
+		 * Try:
+		 * trap '' hup; bash; echo RET  # type "kill -hup $$", see SIGHUP having effect
+		 * trap '' hup; bash -c 'kill -hup $$; echo ALIVE'  # here SIGHUP is SIG_IGNed
+		 */
+		if (sig == SIGHUP && G_interactive_fd)
+			continue;
+		/* Unless one of the above signals, is it SIG_IGN? */
+		if (old_handler == SIG_IGN) {
+			/* oops... restore back to IGN, and record this fact */
+			install_sighandler(sig, old_handler);
+#if ENABLE_HUSH_TRAP
+			if (!G_traps)
+				G_traps = xzalloc(sizeof(G_traps[0]) * NSIG);
+			free(G_traps[sig]);
+			G_traps[sig] = xzalloc(1); /* == xstrdup(""); */
+#endif
+		}
+	}
+}
+
+/* Called a few times only (or even once if "sh -c") */
+static void install_special_sighandlers(void)
+{
+	unsigned mask;
+
+	/* Which signals are shell-special? */
+	mask = (1 << SIGQUIT) | (1 << SIGCHLD);
+	if (G_interactive_fd) {
+		mask |= SPECIAL_INTERACTIVE_SIGS;
+		if (G_saved_tty_pgrp) /* we have ctty, job control sigs work */
+			mask |= SPECIAL_JOBSTOP_SIGS;
+	}
+	/* Careful, do not re-install handlers we already installed */
+	if (G.special_sig_mask != mask) {
+		unsigned diff = mask & ~G.special_sig_mask;
+		G.special_sig_mask = mask;
+		install_sighandlers(diff);
+	}
+}
+
+#if ENABLE_HUSH_JOB
+/* helper */
+/* Set handlers to restore tty pgrp and exit */
+static void install_fatal_sighandlers(void)
+{
+	unsigned mask;
+
+	/* We will restore tty pgrp on these signals */
+	mask = 0
+		/*+ (1 << SIGILL ) * HUSH_DEBUG*/
+		/*+ (1 << SIGFPE ) * HUSH_DEBUG*/
+		+ (1 << SIGBUS ) * HUSH_DEBUG
+		+ (1 << SIGSEGV) * HUSH_DEBUG
+		/*+ (1 << SIGTRAP) * HUSH_DEBUG*/
+		+ (1 << SIGABRT)
+	/* bash 3.2 seems to handle these just like 'fatal' ones */
+		+ (1 << SIGPIPE)
+		+ (1 << SIGALRM)
+	/* if we are interactive, SIGHUP, SIGTERM and SIGINT are special sigs.
+	 * if we aren't interactive... but in this case
+	 * we never want to restore pgrp on exit, and this fn is not called
+	 */
+		/*+ (1 << SIGHUP )*/
+		/*+ (1 << SIGTERM)*/
+		/*+ (1 << SIGINT )*/
+	;
+	G_fatal_sig_mask = mask;
+
+	install_sighandlers(mask);
+}
+#endif
+
+static int set_mode(int state, char mode, const char *o_opt)
+{
+	int idx;
+	switch (mode) {
+	case 'n':
+		G.o_opt[OPT_O_NOEXEC] = state;
+		break;
+	case 'x':
+		IF_HUSH_MODE_X(G_x_mode = state;)
+		IF_HUSH_MODE_X(if (G.x_mode_fd <= 0) G.x_mode_fd = dup_CLOEXEC(2, 10);)
+		break;
+	case 'e':
+		G.o_opt[OPT_O_ERREXIT] = state;
+		break;
+	case 'o':
+		if (!o_opt) {
+			/* "set -o" or "set +o" without parameter.
+			 * in bash, set -o produces this output:
+			 *  pipefail        off
+			 * and set +o:
+			 *  set +o pipefail
+			 * We always use the second form.
+			 */
+			const char *p = o_opt_strings;
+			idx = 0;
+			while (*p) {
+				printf("set %co %s\n", (G.o_opt[idx] ? '-' : '+'), p);
+				idx++;
+				p += strlen(p) + 1;
+			}
+			break;
+		}
+		idx = index_in_strings(o_opt_strings, o_opt);
+		if (idx >= 0) {
+			G.o_opt[idx] = state;
+			break;
+		}
+		/* fall through to error */
+	default:
+		return EXIT_FAILURE;
+	}
+	return EXIT_SUCCESS;
+}
+
+int hush_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int hush_main(int argc, char **argv)
+{
+	pid_t cached_getpid;
+	enum {
+		OPT_login = (1 << 0),
+	};
+	unsigned flags;
+#if !BB_MMU
+	unsigned builtin_argc = 0;
+#endif
+	char **e;
+	struct variable *cur_var;
+	struct variable *shell_ver;
+
+	INIT_G();
+	if (EXIT_SUCCESS != 0) /* if EXIT_SUCCESS == 0, it is already done */
+		G.last_exitcode = EXIT_SUCCESS;
+#if ENABLE_HUSH_TRAP
+# if ENABLE_HUSH_FUNCTIONS
+	G.return_exitcode = -1;
+# endif
+	G.pre_trap_exitcode = -1;
+#endif
+
+#if ENABLE_HUSH_FAST
+	G.count_SIGCHLD++; /* ensure it is != G.handled_SIGCHLD */
+#endif
+#if !BB_MMU
+	G.argv0_for_re_execing = argv[0];
+#endif
+
+	cached_getpid = getpid();   /* for tcsetpgrp() during init */
+	G.root_pid = cached_getpid; /* for $PID  (NOMMU can override via -$HEXPID:HEXPPID:...) */
+	G.root_ppid = getppid();    /* for $PPID (NOMMU can override)  */
+
+	/* Deal with HUSH_VERSION */
+	debug_printf_env("unsetenv '%s'\n", "HUSH_VERSION");
+	unsetenv("HUSH_VERSION"); /* in case it exists in initial env */
+	shell_ver = xzalloc(sizeof(*shell_ver));
+	shell_ver->flg_export = 1;
+	shell_ver->flg_read_only = 1;
+	/* Code which handles ${var<op>...} needs writable values for all variables,
+	 * therefore we xstrdup: */
+	shell_ver->varstr = xstrdup(hush_version_str);
+
+	/* Create shell local variables from the values
+	 * currently living in the environment */
+	G.top_var = shell_ver;
+	cur_var = G.top_var;
+	e = environ;
+	if (e) while (*e) {
+		char *value = strchr(*e, '=');
+		if (value) { /* paranoia */
+			cur_var->next = xzalloc(sizeof(*cur_var));
+			cur_var = cur_var->next;
+			cur_var->varstr = *e;
+			cur_var->max_len = strlen(*e);
+			cur_var->flg_export = 1;
+		}
+		e++;
+	}
+	/* (Re)insert HUSH_VERSION into env (AFTER we scanned the env!) */
+	debug_printf_env("putenv '%s'\n", shell_ver->varstr);
+	putenv(shell_ver->varstr);
+
+	/* Export PWD */
+	set_pwd_var(SETFLAG_EXPORT);
+
+#if BASH_HOSTNAME_VAR
+	/* Set (but not export) HOSTNAME unless already set */
+	if (!get_local_var_value("HOSTNAME")) {
+		struct utsname uts;
+		uname(&uts);
+		set_local_var_from_halves("HOSTNAME", uts.nodename);
+	}
+#endif
+	/* IFS is not inherited from the parent environment */
+	set_local_var_from_halves("IFS", defifs);
+
+	if (!get_local_var_value("PATH"))
+		set_local_var_from_halves("PATH", bb_default_root_path);
+
+	/* PS1/PS2 are set later, if we determine that we are interactive */
+
+	/* bash also exports SHLVL and _,
+	 * and sets (but doesn't export) the following variables:
+	 * BASH=/bin/bash
+	 * BASH_VERSINFO=([0]="3" [1]="2" [2]="0" [3]="1" [4]="release" [5]="i386-pc-linux-gnu")
+	 * BASH_VERSION='3.2.0(1)-release'
+	 * HOSTTYPE=i386
+	 * MACHTYPE=i386-pc-linux-gnu
+	 * OSTYPE=linux-gnu
+	 * PPID=<NNNNN> - we also do it elsewhere
+	 * EUID=<NNNNN>
+	 * UID=<NNNNN>
+	 * GROUPS=()
+	 * LINES=<NNN>
+	 * COLUMNS=<NNN>
+	 * BASH_ARGC=()
+	 * BASH_ARGV=()
+	 * BASH_LINENO=()
+	 * BASH_SOURCE=()
+	 * DIRSTACK=()
+	 * PIPESTATUS=([0]="0")
+	 * HISTFILE=/<xxx>/.bash_history
+	 * HISTFILESIZE=500
+	 * HISTSIZE=500
+	 * MAILCHECK=60
+	 * PATH=/usr/gnu/bin:/usr/local/bin:/bin:/usr/bin:.
+	 * SHELL=/bin/bash
+	 * SHELLOPTS=braceexpand:emacs:hashall:histexpand:history:interactive-comments:monitor
+	 * TERM=dumb
+	 * OPTERR=1
+	 * OPTIND=1
+	 * PS4='+ '
+	 */
+
+#if NUM_SCRIPTS > 0
+	if (argc < 0) {
+		char *script = get_script_content(-argc - 1);
+		G.global_argv = argv;
+		G.global_argc = string_array_len(argv);
+		//install_special_sighandlers(); - needed?
+		parse_and_run_string(script);
+		goto final_return;
+	}
+#endif
+
+	/* Initialize some more globals to non-zero values */
+	die_func = restore_ttypgrp_and__exit;
+
+	/* Shell is non-interactive at first. We need to call
+	 * install_special_sighandlers() if we are going to execute "sh <script>",
+	 * "sh -c <cmds>" or login shell's /etc/profile and friends.
+	 * If we later decide that we are interactive, we run install_special_sighandlers()
+	 * in order to intercept (more) signals.
+	 */
+
+	/* Parse options */
+	/* http://www.opengroup.org/onlinepubs/9699919799/utilities/sh.html */
+	flags = (argv[0] && argv[0][0] == '-') ? OPT_login : 0;
+	while (1) {
+		int opt = getopt(argc, argv, "+" /* stop at 1st non-option */
+				"cexinsl"
+#if !BB_MMU
+				"<:$:R:V:"
+# if ENABLE_HUSH_FUNCTIONS
+				"F:"
+# endif
+#endif
+		);
+		if (opt <= 0)
+			break;
+		switch (opt) {
+		case 'c':
+			/* Note: -c is not an option with param!
+			 * "hush -c -l SCRIPT" is valid. "hush -cSCRIPT" is not.
+			 */
+			G.opt_c = 1;
+			break;
+		case 'i':
+			/* Well, we cannot just declare interactiveness,
+			 * we have to have some stuff (ctty, etc) */
+			/* G_interactive_fd++; */
+			break;
+		case 's':
+			G.opt_s = 1;
+			break;
+		case 'l':
+			flags |= OPT_login;
+			break;
+#if !BB_MMU
+		case '<': /* "big heredoc" support */
+			full_write1_str(optarg);
+			_exit(0);
+		case '$': {
+			unsigned long long empty_trap_mask;
+
+			G.root_pid = bb_strtou(optarg, &optarg, 16);
+			optarg++;
+			G.root_ppid = bb_strtou(optarg, &optarg, 16);
+			optarg++;
+			G.last_bg_pid = bb_strtou(optarg, &optarg, 16);
+			optarg++;
+			G.last_exitcode = bb_strtou(optarg, &optarg, 16);
+			optarg++;
+			builtin_argc = bb_strtou(optarg, &optarg, 16);
+			optarg++;
+			empty_trap_mask = bb_strtoull(optarg, &optarg, 16);
+			if (empty_trap_mask != 0) {
+				IF_HUSH_TRAP(int sig;)
+				install_special_sighandlers();
+# if ENABLE_HUSH_TRAP
+				G_traps = xzalloc(sizeof(G_traps[0]) * NSIG);
+				for (sig = 1; sig < NSIG; sig++) {
+					if (empty_trap_mask & (1LL << sig)) {
+						G_traps[sig] = xzalloc(1); /* == xstrdup(""); */
+						install_sighandler(sig, SIG_IGN);
+					}
+				}
+# endif
+			}
+# if ENABLE_HUSH_LOOPS
+			optarg++;
+			G.depth_of_loop = bb_strtou(optarg, &optarg, 16);
+# endif
+			/* Suppress "killed by signal" message, -$ hack is used
+			 * for subshells: echo `sh -c 'kill -9 $$'`
+			 * should be silent.
+			 */
+			IF_HUSH_JOB(G.run_list_level = 1;)
+# if ENABLE_HUSH_FUNCTIONS
+			/* nommu uses re-exec trick for "... | func | ...",
+			 * should allow "return".
+			 * This accidentally allows returns in subshells.
+			 */
+			G_flag_return_in_progress = -1;
+# endif
+			break;
+		}
+		case 'R':
+		case 'V':
+			set_local_var(xstrdup(optarg), opt == 'R' ? SETFLAG_MAKE_RO : 0);
+			break;
+# if ENABLE_HUSH_FUNCTIONS
+		case 'F': {
+			struct function *funcp = new_function(optarg);
+			/* funcp->name is already set to optarg */
+			/* funcp->body is set to NULL. It's a special case. */
+			funcp->body_as_string = argv[optind];
+			optind++;
+			break;
+		}
+# endif
+#endif
+		/*case '?': invalid option encountered (set_mode('?') will fail) */
+		/*case 'n':*/
+		/*case 'x':*/
+		/*case 'e':*/
+		default:
+			if (set_mode(1, opt, NULL) == 0) /* no error */
+				break;
+			bb_show_usage();
+		}
+	} /* option parsing loop */
+
+	/* Skip options. Try "hush -l": $1 should not be "-l"! */
+	G.global_argc = argc - (optind - 1);
+	G.global_argv = argv + (optind - 1);
+	G.global_argv[0] = argv[0];
+
+	/* If we are login shell... */
+	if (flags & OPT_login) {
+		const char *hp = NULL;
+		HFILE *input;
+
+		debug_printf("sourcing /etc/profile\n");
+		input = hfopen("/etc/profile");
+ run_profile:
+		if (input != NULL) {
+			install_special_sighandlers();
+			parse_and_run_file(input);
+			hfclose(input);
+		}
+		/* bash: after sourcing /etc/profile,
+		 * tries to source (in the given order):
+		 * ~/.bash_profile, ~/.bash_login, ~/.profile,
+		 * stopping on first found. --noprofile turns this off.
+		 * bash also sources ~/.bash_logout on exit.
+		 * If called as sh, skips .bash_XXX files.
+		 */
+		if (!hp) { /* unless we looped on the "goto" already */
+			hp = get_local_var_value("HOME");
+			if (hp && hp[0]) {
+				debug_printf("sourcing ~/.profile\n");
+				hp = concat_path_file(hp, ".profile");
+				input = hfopen(hp);
+				free((char*)hp);
+				goto run_profile;
+			}
+		}
+	}
+
+	/* -c takes effect *after* -l */
+	if (G.opt_c) {
+		/* Possibilities:
+		 * sh ... -c 'script'
+		 * sh ... -c 'script' ARG0 [ARG1...]
+		 * On NOMMU, if builtin_argc != 0,
+		 * sh ... -c 'builtin' BARGV... "" ARG0 [ARG1...]
+		 * "" needs to be replaced with NULL
+		 * and BARGV vector fed to builtin function.
+		 * Note: the form without ARG0 never happens:
+		 * sh ... -c 'builtin' BARGV... ""
+		 */
+		char *script;
+
+		install_special_sighandlers();
+
+		G.global_argc--;
+		G.global_argv++;
+#if !BB_MMU
+		if (builtin_argc) {
+			/* -c 'builtin' [BARGV...] "" ARG0 [ARG1...] */
+			const struct built_in_command *x;
+			x = find_builtin(G.global_argv[0]);
+			if (x) { /* paranoia */
+				argv = G.global_argv;
+				G.global_argc -= builtin_argc + 1; /* skip [BARGV...] "" */
+				G.global_argv += builtin_argc + 1;
+				G.global_argv[-1] = NULL; /* replace "" */
+				G.last_exitcode = x->b_function(argv);
+			}
+			goto final_return;
+		}
+#endif
+
+		script = G.global_argv[0];
+		if (!script)
+			bb_error_msg_and_die(bb_msg_requires_arg, "-c");
+		if (!G.global_argv[1]) {
+			/* -c 'script' (no params): prevent empty $0 */
+			G.global_argv[0] = argv[0];
+		} else { /* else -c 'script' ARG0 [ARG1...]: $0 is ARG0 */
+			G.global_argc--;
+			G.global_argv++;
+		}
+		parse_and_run_string(script);
+		goto final_return;
+	}
+
+	/* -s is: hush -s ARGV1 ARGV2 (no SCRIPT) */
+	if (!G.opt_s && G.global_argv[1]) {
+		HFILE *input;
+		/*
+		 * "bash <script>" (which is never interactive (unless -i?))
+		 * sources $BASH_ENV here (without scanning $PATH).
+		 * If called as sh, does the same but with $ENV.
+		 * Also NB, per POSIX, $ENV should undergo parameter expansion.
+		 */
+		G.global_argc--;
+		G.global_argv++;
+		debug_printf("running script '%s'\n", G.global_argv[0]);
+		xfunc_error_retval = 127; /* for "hush /does/not/exist" case */
+		input = hfopen(G.global_argv[0]);
+		if (!input) {
+			bb_simple_perror_msg_and_die(G.global_argv[0]);
+		}
+		xfunc_error_retval = 1;
+		install_special_sighandlers();
+		parse_and_run_file(input);
+#if ENABLE_FEATURE_CLEAN_UP
+		hfclose(input);
+#endif
+		goto final_return;
+	}
+	/* "implicit" -s: bare interactive hush shows 's' in $- */
+	G.opt_s = 1;
+
+	/* Up to here, shell was non-interactive. Now it may become one.
+	 * NB: don't forget to (re)run install_special_sighandlers() as needed.
+	 */
+
+	/* A shell is interactive if the '-i' flag was given,
+	 * or if all of the following conditions are met:
+	 *    no -c command
+	 *    no arguments remaining or the -s flag given
+	 *    standard input is a terminal
+	 *    standard output is a terminal
+	 * Refer to Posix.2, the description of the 'sh' utility.
+	 */
+#if ENABLE_HUSH_JOB
+	if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
+		G_saved_tty_pgrp = tcgetpgrp(STDIN_FILENO);
+		debug_printf("saved_tty_pgrp:%d\n", G_saved_tty_pgrp);
+		if (G_saved_tty_pgrp < 0)
+			G_saved_tty_pgrp = 0;
+
+		/* try to dup stdin to high fd#, >= 255 */
+		G_interactive_fd = dup_CLOEXEC(STDIN_FILENO, 254);
+		if (G_interactive_fd < 0) {
+			/* try to dup to any fd */
+			G_interactive_fd = dup(STDIN_FILENO);
+			if (G_interactive_fd < 0) {
+				/* give up */
+				G_interactive_fd = 0;
+				G_saved_tty_pgrp = 0;
+			}
+		}
+	}
+	debug_printf("interactive_fd:%d\n", G_interactive_fd);
+	if (G_interactive_fd) {
+		close_on_exec_on(G_interactive_fd);
+
+		if (G_saved_tty_pgrp) {
+			/* If we were run as 'hush &', sleep until we are
+			 * in the foreground (tty pgrp == our pgrp).
+			 * If we get started under a job aware app (like bash),
+			 * make sure we are now in charge so we don't fight over
+			 * who gets the foreground */
+			while (1) {
+				pid_t shell_pgrp = getpgrp();
+				G_saved_tty_pgrp = tcgetpgrp(G_interactive_fd);
+				if (G_saved_tty_pgrp == shell_pgrp)
+					break;
+				/* send TTIN to ourself (should stop us) */
+				kill(- shell_pgrp, SIGTTIN);
+			}
+		}
+
+		/* Install more signal handlers */
+		install_special_sighandlers();
+
+		if (G_saved_tty_pgrp) {
+			/* Set other signals to restore saved_tty_pgrp */
+			install_fatal_sighandlers();
+			/* Put ourselves in our own process group
+			 * (bash, too, does this only if ctty is available) */
+			bb_setpgrp(); /* is the same as setpgid(our_pid, our_pid); */
+			/* Grab control of the terminal */
+			tcsetpgrp(G_interactive_fd, cached_getpid);
+		}
+		enable_restore_tty_pgrp_on_exit();
+
+# if ENABLE_FEATURE_EDITING
+		G.line_input_state = new_line_input_t(FOR_SHELL);
+#  if EDITING_HAS_get_exe_name
+		G.line_input_state->get_exe_name = get_builtin_name;
+#  endif
+# endif
+# if ENABLE_HUSH_SAVEHISTORY && MAX_HISTORY > 0
+		{
+			const char *hp = get_local_var_value("HISTFILE");
+			if (!hp) {
+				hp = get_local_var_value("HOME");
+				if (hp)
+					hp = concat_path_file(hp, ".hush_history");
+			} else {
+				hp = xstrdup(hp);
+			}
+			if (hp) {
+				G.line_input_state->hist_file = hp;
+				//set_local_var(xasprintf("HISTFILE=%s", ...));
+			}
+#  if ENABLE_FEATURE_SH_HISTFILESIZE
+			hp = get_local_var_value("HISTFILESIZE");
+			G.line_input_state->max_history = size_from_HISTFILESIZE(hp);
+#  endif
+		}
+# endif
+	} else {
+		install_special_sighandlers();
+	}
+#elif ENABLE_HUSH_INTERACTIVE
+	/* No job control compiled in, only prompt/line editing */
+	if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
+		G_interactive_fd = dup_CLOEXEC(STDIN_FILENO, 254);
+		if (G_interactive_fd < 0) {
+			/* try to dup to any fd */
+			G_interactive_fd = dup_CLOEXEC(STDIN_FILENO, -1);
+			if (G_interactive_fd < 0)
+				/* give up */
+				G_interactive_fd = 0;
+		}
+	}
+	if (G_interactive_fd) {
+		close_on_exec_on(G_interactive_fd);
+	}
+	install_special_sighandlers();
+#else
+	/* We have interactiveness code disabled */
+	install_special_sighandlers();
+#endif
+	/* bash:
+	 * if interactive but not a login shell, sources ~/.bashrc
+	 * (--norc turns this off, --rcfile <file> overrides)
+	 */
+
+	if (G_interactive_fd) {
+#if ENABLE_HUSH_INTERACTIVE && ENABLE_FEATURE_EDITING_FANCY_PROMPT
+		/* Set (but not export) PS1/2 unless already set */
+		if (!get_local_var_value("PS1"))
+			set_local_var_from_halves("PS1", "\\w \\$ ");
+		if (!get_local_var_value("PS2"))
+			set_local_var_from_halves("PS2", "> ");
+#endif
+		if (!ENABLE_FEATURE_SH_EXTRA_QUIET) {
+			/* note: ash and hush share this string */
+			printf("\n\n%s %s\n"
+				IF_HUSH_HELP("Enter 'help' for a list of built-in commands.\n")
+				"\n",
+				bb_banner,
+				"hush - the humble shell"
+			);
+		}
+	}
+
+	parse_and_run_file(hfopen(NULL)); /* stdin */
+
+ final_return:
+	hush_exit(G.last_exitcode);
+}
+
+
+/*
+ * Built-ins
+ */
+static int FAST_FUNC builtin_true(char **argv UNUSED_PARAM)
+{
+	return 0;
+}
+
+#if ENABLE_HUSH_TEST || ENABLE_HUSH_ECHO || ENABLE_HUSH_PRINTF || ENABLE_HUSH_KILL
+static NOINLINE int run_applet_main(char **argv, int (*applet_main_func)(int argc, char **argv))
+{
+	int argc = string_array_len(argv);
+	return applet_main_func(argc, argv);
+}
+#endif
+#if ENABLE_HUSH_TEST || BASH_TEST2
+static int FAST_FUNC builtin_test(char **argv)
+{
+	return run_applet_main(argv, test_main);
+}
+#endif
+#if ENABLE_HUSH_ECHO
+static int FAST_FUNC builtin_echo(char **argv)
+{
+	return run_applet_main(argv, echo_main);
+}
+#endif
+#if ENABLE_HUSH_PRINTF
+static int FAST_FUNC builtin_printf(char **argv)
+{
+	return run_applet_main(argv, printf_main);
+}
+#endif
+
+#if ENABLE_HUSH_HELP
+static int FAST_FUNC builtin_help(char **argv UNUSED_PARAM)
+{
+	const struct built_in_command *x;
+
+	printf(
+		"Built-in commands:\n"
+		"------------------\n");
+	for (x = bltins1; x != &bltins1[ARRAY_SIZE(bltins1)]; x++) {
+		if (x->b_descr)
+			printf("%-10s%s\n", x->b_cmd, x->b_descr);
+	}
+	return EXIT_SUCCESS;
+}
+#endif
+
+#if MAX_HISTORY && ENABLE_FEATURE_EDITING
+static int FAST_FUNC builtin_history(char **argv UNUSED_PARAM)
+{
+	show_history(G.line_input_state);
+	return EXIT_SUCCESS;
+}
+#endif
+
+static char **skip_dash_dash(char **argv)
+{
+	argv++;
+	if (argv[0] && argv[0][0] == '-' && argv[0][1] == '-' && argv[0][2] == '\0')
+		argv++;
+	return argv;
+}
+
+static int FAST_FUNC builtin_cd(char **argv)
+{
+	const char *newdir;
+
+	argv = skip_dash_dash(argv);
+	newdir = argv[0];
+	if (newdir == NULL) {
+		/* bash does nothing (exitcode 0) if HOME is ""; if it's unset,
+		 * bash says "bash: cd: HOME not set" and does nothing
+		 * (exitcode 1)
+		 */
+		const char *home = get_local_var_value("HOME");
+		newdir = home ? home : "/";
+	}
+	if (chdir(newdir)) {
+		/* Mimic bash message exactly */
+		bb_perror_msg("cd: %s", newdir);
+		return EXIT_FAILURE;
+	}
+	/* Read current dir (get_cwd(1) is inside) and set PWD.
+	 * Note: do not enforce exporting. If PWD was unset or unexported,
+	 * set it again, but do not export. bash does the same.
+	 */
+	set_pwd_var(/*flag:*/ 0);
+	return EXIT_SUCCESS;
+}
+
+static int FAST_FUNC builtin_pwd(char **argv UNUSED_PARAM)
+{
+	puts(get_cwd(0));
+	return EXIT_SUCCESS;
+}
+
+static int FAST_FUNC builtin_eval(char **argv)
+{
+	argv = skip_dash_dash(argv);
+
+	if (!argv[0])
+		return EXIT_SUCCESS;
+
+	IF_HUSH_MODE_X(G.x_mode_depth++;)
+	//bb_error_msg("%s: ++x_mode_depth=%d", __func__, G.x_mode_depth);
+	if (!argv[1]) {
+		/* bash:
+		 * eval "echo Hi; done" ("done" is syntax error):
+		 * "echo Hi" will not execute too.
+		 */
+		parse_and_run_string(argv[0]);
+	} else {
+		/* "The eval utility shall construct a command by
+		 * concatenating arguments together, separating
+		 * each with a <space> character."
+		 */
+		char *str, *p;
+		unsigned len = 0;
+		char **pp = argv;
+		do
+			len += strlen(*pp) + 1;
+		while (*++pp);
+		str = p = xmalloc(len);
+		pp = argv;
+		for (;;) {
+			p = stpcpy(p, *pp);
+			pp++;
+			if (!*pp)
+				break;
+			*p++ = ' ';
+		}
+		parse_and_run_string(str);
+		free(str);
+	}
+	IF_HUSH_MODE_X(G.x_mode_depth--;)
+	//bb_error_msg("%s: --x_mode_depth=%d", __func__, G.x_mode_depth);
+	return G.last_exitcode;
+}
+
+static int FAST_FUNC builtin_exec(char **argv)
+{
+	argv = skip_dash_dash(argv);
+	if (argv[0] == NULL)
+		return EXIT_SUCCESS; /* bash does this */
+
+	/* Careful: we can end up here after [v]fork. Do not restore
+	 * tty pgrp then, only top-level shell process does that */
+	if (G_saved_tty_pgrp && getpid() == G.root_pid)
+		tcsetpgrp(G_interactive_fd, G_saved_tty_pgrp);
+
+	/* Saved-redirect fds, script fds and G_interactive_fd are still
+	 * open here. However, they are all CLOEXEC, and execv below
+	 * closes them. Try interactive "exec ls -l /proc/self/fd",
+	 * it should show no extra open fds in the "ls" process.
+	 * If we'd try to run builtins/NOEXECs, this would need improving.
+	 */
+	//close_saved_fds_and_FILE_fds();
+
+	/* TODO: if exec fails, bash does NOT exit! We do.
+	 * We'll need to undo trap cleanup (it's inside execvp_or_die)
+	 * and tcsetpgrp, and this is inherently racy.
+	 */
+	execvp_or_die(argv);
+}
+
+static int FAST_FUNC builtin_exit(char **argv)
+{
+	debug_printf_exec("%s()\n", __func__);
+
+	/* interactive bash:
+	 * # trap "echo EEE" EXIT
+	 * # exit
+	 * exit
+	 * There are stopped jobs.
+	 * (if there are _stopped_ jobs, running ones don't count)
+	 * # exit
+	 * exit
+	 * EEE (then bash exits)
+	 *
+	 * TODO: we can use G.exiting = -1 as indicator "last cmd was exit"
+	 */
+
+	/* note: EXIT trap is run by hush_exit */
+	argv = skip_dash_dash(argv);
+	if (argv[0] == NULL) {
+#if ENABLE_HUSH_TRAP
+		if (G.pre_trap_exitcode >= 0) /* "exit" in trap uses $? from before the trap */
+			hush_exit(G.pre_trap_exitcode);
+#endif
+		hush_exit(G.last_exitcode);
+	}
+	/* mimic bash: exit 123abc == exit 255 + error msg */
+	xfunc_error_retval = 255;
+	/* bash: exit -2 == exit 254, no error msg */
+	hush_exit(xatoi(argv[0]) & 0xff);
+}
+
+#if ENABLE_HUSH_TYPE
+/* http://www.opengroup.org/onlinepubs/9699919799/utilities/type.html */
+static int FAST_FUNC builtin_type(char **argv)
+{
+	int ret = EXIT_SUCCESS;
+
+	while (*++argv) {
+		const char *type;
+		char *path = NULL;
+
+		if (0) {} /* make conditional compile easier below */
+		/*else if (find_alias(*argv))
+			type = "an alias";*/
+# if ENABLE_HUSH_FUNCTIONS
+		else if (find_function(*argv))
+			type = "a function";
+# endif
+		else if (find_builtin(*argv))
+			type = "a shell builtin";
+		else if ((path = find_in_path(*argv)) != NULL)
+			type = path;
+		else {
+			bb_error_msg("type: %s: not found", *argv);
+			ret = EXIT_FAILURE;
+			continue;
+		}
+
+		printf("%s is %s\n", *argv, type);
+		free(path);
+	}
+
+	return ret;
+}
+#endif
+
+#if ENABLE_HUSH_READ
+/* Interruptibility of read builtin in bash
+ * (tested on bash-4.2.8 by sending signals (not by ^C)):
+ *
+ * Empty trap makes read ignore corresponding signal, for any signal.
+ *
+ * SIGINT:
+ * - terminates non-interactive shell;
+ * - interrupts read in interactive shell;
+ * if it has non-empty trap:
+ * - executes trap and returns to command prompt in interactive shell;
+ * - executes trap and returns to read in non-interactive shell;
+ * SIGTERM:
+ * - is ignored (does not interrupt) read in interactive shell;
+ * - terminates non-interactive shell;
+ * if it has non-empty trap:
+ * - executes trap and returns to read;
+ * SIGHUP:
+ * - terminates shell (regardless of interactivity);
+ * if it has non-empty trap:
+ * - executes trap and returns to read;
+ * SIGCHLD from children:
+ * - does not interrupt read regardless of interactivity:
+ *   try: sleep 1 & read x; echo $x
+ */
+static int FAST_FUNC builtin_read(char **argv)
+{
+	const char *r;
+	struct builtin_read_params params;
+
+	memset(&params, 0, sizeof(params));
+
+	/* "!": do not abort on errors.
+	 * Option string must start with "sr" to match BUILTIN_READ_xxx
+	 */
+	params.read_flags = getopt32(argv,
+# if BASH_READ_D
+		IF_NOT_HUSH_BASH_COMPAT("^")
+		"!srn:p:t:u:d:" IF_NOT_HUSH_BASH_COMPAT("\0" "-1"/*min 1 arg*/),
+		&params.opt_n, &params.opt_p, &params.opt_t, &params.opt_u, &params.opt_d
+# else
+		IF_NOT_HUSH_BASH_COMPAT("^")
+		"!srn:p:t:u:" IF_NOT_HUSH_BASH_COMPAT("\0" "-1"/*min 1 arg*/),
+		&params.opt_n, &params.opt_p, &params.opt_t, &params.opt_u
+# endif
+//TODO: print "read: need variable name"
+//for the case of !BASH "read" with no args (now it fails silently)
+//(or maybe extend getopt32() to emit a message if "-1" fails)
+	);
+	if ((uint32_t)params.read_flags == (uint32_t)-1)
+		return EXIT_FAILURE;
+	argv += optind;
+	params.argv = argv;
+	params.setvar = set_local_var_from_halves;
+	params.ifs = get_local_var_value("IFS"); /* can be NULL */
+
+ again:
+	r = shell_builtin_read(&params);
+
+	if ((uintptr_t)r == 1 && errno == EINTR) {
+		unsigned sig = check_and_run_traps();
+		if (sig != SIGINT)
+			goto again;
+	}
+
+	if ((uintptr_t)r > 1) {
+		bb_simple_error_msg(r);
+		r = (char*)(uintptr_t)1;
+	}
+
+	return (uintptr_t)r;
+}
+#endif
+
+#if ENABLE_HUSH_UMASK
+static int FAST_FUNC builtin_umask(char **argv)
+{
+	int rc;
+	mode_t mask;
+
+	rc = 1;
+	mask = umask(0);
+	argv = skip_dash_dash(argv);
+	if (argv[0]) {
+		mode_t old_mask = mask;
+
+		/* numeric umasks are taken as-is */
+		/* symbolic umasks are inverted: "umask a=rx" calls umask(222) */
+		if (!isdigit(argv[0][0]))
+			mask ^= 0777;
+		mask = bb_parse_mode(argv[0], mask);
+		if (!isdigit(argv[0][0]))
+			mask ^= 0777;
+		if ((unsigned)mask > 0777) {
+			mask = old_mask;
+			/* bash messages:
+			 * bash: umask: 'q': invalid symbolic mode operator
+			 * bash: umask: 999: octal number out of range
+			 */
+			bb_error_msg("%s: invalid mode '%s'", "umask", argv[0]);
+			rc = 0;
+		}
+	} else {
+		/* Mimic bash */
+		printf("%04o\n", (unsigned) mask);
+		/* fall through and restore mask which we set to 0 */
+	}
+	umask(mask);
+
+	return !rc; /* rc != 0 - success */
+}
+#endif
+
+#if ENABLE_HUSH_EXPORT || ENABLE_HUSH_TRAP
+static void print_escaped(const char *s)
+{
+	if (*s == '\'')
+		goto squote;
+	do {
+		const char *p = strchrnul(s, '\'');
+		/* print 'xxxx', possibly just '' */
+		printf("'%.*s'", (int)(p - s), s);
+		if (*p == '\0')
+			break;
+		s = p;
+ squote:
+		/* s points to '; print "'''...'''" */
+		putchar('"');
+		do putchar('\''); while (*++s == '\'');
+		putchar('"');
+	} while (*s);
+}
+#endif
+
+#if ENABLE_HUSH_EXPORT || ENABLE_HUSH_LOCAL || ENABLE_HUSH_READONLY
+static int helper_export_local(char **argv, unsigned flags)
+{
+	do {
+		char *name = *argv;
+		const char *name_end = endofname(name);
+
+		if (*name_end == '\0') {
+			struct variable *var, **vpp;
+
+			vpp = get_ptr_to_local_var(name, name_end - name);
+			var = vpp ? *vpp : NULL;
+
+			if (flags & SETFLAG_UNEXPORT) {
+				/* export -n NAME (without =VALUE) */
+				if (var) {
+					var->flg_export = 0;
+					debug_printf_env("%s: unsetenv '%s'\n", __func__, name);
+					unsetenv(name);
+				} /* else: export -n NOT_EXISTING_VAR: no-op */
+				continue;
+			}
+			if (flags & SETFLAG_EXPORT) {
+				/* export NAME (without =VALUE) */
+				if (var) {
+					var->flg_export = 1;
+					debug_printf_env("%s: putenv '%s'\n", __func__, var->varstr);
+					putenv(var->varstr);
+					continue;
+				}
+			}
+			if (flags & SETFLAG_MAKE_RO) {
+				/* readonly NAME (without =VALUE) */
+				if (var) {
+					var->flg_read_only = 1;
+					continue;
+				}
+			}
+# if ENABLE_HUSH_LOCAL
+			/* Is this "local" bltin? */
+			if (!(flags & (SETFLAG_EXPORT|SETFLAG_UNEXPORT|SETFLAG_MAKE_RO))) {
+				unsigned lvl = flags >> SETFLAG_VARLVL_SHIFT;
+				if (var && var->var_nest_level == lvl) {
+					/* "local x=abc; ...; local x" - ignore second local decl */
+					continue;
+				}
+			}
+# endif
+			/* Exporting non-existing variable.
+			 * bash does not put it in environment,
+			 * but remembers that it is exported,
+			 * and does put it in env when it is set later.
+			 * We just set it to "" and export.
+			 */
+			/* Or, it's "local NAME" (without =VALUE).
+			 * bash sets the value to "".
+			 */
+			/* Or, it's "readonly NAME" (without =VALUE).
+			 * bash remembers NAME and disallows its creation
+			 * in the future.
+			 */
+			name = xasprintf("%s=", name);
+		} else {
+			if (*name_end != '=') {
+				bb_error_msg("'%s': bad variable name", name);
+				/* do not parse following argv[]s: */
+				return 1;
+			}
+			/* (Un)exporting/making local NAME=VALUE */
+			name = xstrdup(name);
+			/* Testcase: export PS1='\w \$ ' */
+			unbackslash(name);
+		}
+		debug_printf_env("%s: set_local_var('%s')\n", __func__, name);
+		if (set_local_var(name, flags))
+			return EXIT_FAILURE;
+	} while (*++argv);
+	return EXIT_SUCCESS;
+}
+#endif
+
+#if ENABLE_HUSH_EXPORT
+static int FAST_FUNC builtin_export(char **argv)
+{
+	unsigned opt_unexport;
+
+# if ENABLE_HUSH_EXPORT_N
+	/* "!": do not abort on errors */
+	opt_unexport = getopt32(argv, "!n");
+	if (opt_unexport == (uint32_t)-1)
+		return EXIT_FAILURE;
+	argv += optind;
+# else
+	opt_unexport = 0;
+	argv++;
+# endif
+
+	if (argv[0] == NULL) {
+		char **e = environ;
+		if (e) {
+			while (*e) {
+# if 0
+				puts(*e++);
+# else
+				/* ash emits: export VAR='VAL'
+				 * bash: declare -x VAR="VAL"
+				 * we follow ash example */
+				const char *s = *e++;
+				const char *p = strchr(s, '=');
+
+				if (!p) /* wtf? take next variable */
+					continue;
+				/* export var= */
+				printf("export %.*s", (int)(p - s) + 1, s);
+				print_escaped(p + 1);
+				putchar('\n');
+# endif
+			}
+			/*fflush_all(); - done after each builtin anyway */
+		}
+		return EXIT_SUCCESS;
+	}
+
+	return helper_export_local(argv, opt_unexport ? SETFLAG_UNEXPORT : SETFLAG_EXPORT);
+}
+#endif
+
+#if ENABLE_HUSH_LOCAL
+static int FAST_FUNC builtin_local(char **argv)
+{
+	if (G.func_nest_level == 0) {
+		bb_error_msg("%s: not in a function", argv[0]);
+		return EXIT_FAILURE; /* bash compat */
+	}
+	argv++;
+	/* Since all builtins run in a nested variable level,
+	 * need to use level - 1 here. Or else the variable will be removed at once
+	 * after builtin returns.
+	 */
+	return helper_export_local(argv, (G.var_nest_level - 1) << SETFLAG_VARLVL_SHIFT);
+}
+#endif
+
+#if ENABLE_HUSH_READONLY
+static int FAST_FUNC builtin_readonly(char **argv)
+{
+	argv++;
+	if (*argv == NULL) {
+		/* bash: readonly [-p]: list all readonly VARs
+		 * (-p has no effect in bash)
+		 */
+		struct variable *e;
+		for (e = G.top_var; e; e = e->next) {
+			if (e->flg_read_only) {
+//TODO: quote value: readonly VAR='VAL'
+				printf("readonly %s\n", e->varstr);
+			}
+		}
+		return EXIT_SUCCESS;
+	}
+	return helper_export_local(argv, SETFLAG_MAKE_RO);
+}
+#endif
+
+#if ENABLE_HUSH_UNSET
+/* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#unset */
+static int FAST_FUNC builtin_unset(char **argv)
+{
+	int ret;
+	unsigned opts;
+
+	/* "!": do not abort on errors */
+	/* "+": stop at 1st non-option */
+	opts = getopt32(argv, "!+vf");
+	if (opts == (unsigned)-1)
+		return EXIT_FAILURE;
+	if (opts == 3) {
+		bb_simple_error_msg("unset: -v and -f are exclusive");
+		return EXIT_FAILURE;
+	}
+	argv += optind;
+
+	ret = EXIT_SUCCESS;
+	while (*argv) {
+		if (!(opts & 2)) { /* not -f */
+			if (unset_local_var(*argv)) {
+				/* unset <nonexistent_var> doesn't fail.
+				 * Error is when one tries to unset RO var.
+				 * Message was printed by unset_local_var. */
+				ret = EXIT_FAILURE;
+			}
+		}
+# if ENABLE_HUSH_FUNCTIONS
+		else {
+			unset_func(*argv);
+		}
+# endif
+		argv++;
+	}
+	return ret;
+}
+#endif
+
+#if ENABLE_HUSH_SET
+/* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#set
+ * built-in 'set' handler
+ * SUSv3 says:
+ * set [-abCefhmnuvx] [-o option] [argument...]
+ * set [+abCefhmnuvx] [+o option] [argument...]
+ * set -- [argument...]
+ * set -o
+ * set +o
+ * Implementations shall support the options in both their hyphen and
+ * plus-sign forms. These options can also be specified as options to sh.
+ * Examples:
+ * Write out all variables and their values: set
+ * Set $1, $2, and $3 and set "$#" to 3: set c a b
+ * Turn on the -x and -v options: set -xv
+ * Unset all positional parameters: set --
+ * Set $1 to the value of x, even if it begins with '-' or '+': set -- "$x"
+ * Set the positional parameters to the expansion of x, even if x expands
+ * with a leading '-' or '+': set -- $x
+ *
+ * So far, we only support "set -- [argument...]" and some of the short names.
+ */
+static int FAST_FUNC builtin_set(char **argv)
+{
+	int n;
+	char **pp, **g_argv;
+	char *arg = *++argv;
+
+	if (arg == NULL) {
+		struct variable *e;
+		for (e = G.top_var; e; e = e->next)
+			puts(e->varstr);
+		return EXIT_SUCCESS;
+	}
+
+	do {
+		if (strcmp(arg, "--") == 0) {
+			++argv;
+			goto set_argv;
+		}
+		if (arg[0] != '+' && arg[0] != '-')
+			break;
+		for (n = 1; arg[n]; ++n) {
+			if (set_mode((arg[0] == '-'), arg[n], argv[1])) {
+				bb_error_msg("%s: %s: invalid option", "set", arg);
+				return EXIT_FAILURE;
+			}
+			if (arg[n] == 'o' && argv[1])
+				argv++;
+		}
+	} while ((arg = *++argv) != NULL);
+	/* Now argv[0] is 1st argument */
+
+	if (arg == NULL)
+		return EXIT_SUCCESS;
+ set_argv:
+
+	/* NB: G.global_argv[0] ($0) is never freed/changed */
+	g_argv = G.global_argv;
+	if (G.global_args_malloced) {
+		pp = g_argv;
+		while (*++pp)
+			free(*pp);
+		g_argv[1] = NULL;
+	} else {
+		G.global_args_malloced = 1;
+		pp = xzalloc(sizeof(pp[0]) * 2);
+		pp[0] = g_argv[0]; /* retain $0 */
+		g_argv = pp;
+	}
+	/* This realloc's G.global_argv */
+	G.global_argv = pp = add_strings_to_strings(g_argv, argv, /*dup:*/ 1);
+
+	G.global_argc = 1 + string_array_len(pp + 1);
+
+	return EXIT_SUCCESS;
+}
+#endif
+
+static int FAST_FUNC builtin_shift(char **argv)
+{
+	int n = 1;
+	argv = skip_dash_dash(argv);
+	if (argv[0]) {
+		n = bb_strtou(argv[0], NULL, 10);
+		if (errno || n < 0) {
+			/* shared string with ash.c */
+			bb_error_msg("Illegal number: %s", argv[0]);
+			/*
+			 * ash aborts in this case.
+			 * bash prints error message and set $? to 1.
+			 * Interestingly, for "shift 99999" bash does not
+			 * print error message, but does set $? to 1
+			 * (and does no shifting at all).
+			 */
+		}
+	}
+	if (n >= 0 && n < G.global_argc) {
+		if (G_global_args_malloced) {
+			int m = 1;
+			while (m <= n)
+				free(G.global_argv[m++]);
+		}
+		G.global_argc -= n;
+		memmove(&G.global_argv[1], &G.global_argv[n+1],
+				G.global_argc * sizeof(G.global_argv[0]));
+		return EXIT_SUCCESS;
+	}
+	return EXIT_FAILURE;
+}
+
+#if ENABLE_HUSH_GETOPTS
+static int FAST_FUNC builtin_getopts(char **argv)
+{
+/* http://pubs.opengroup.org/onlinepubs/9699919799/utilities/getopts.html
+
+TODO:
+If a required argument is not found, and getopts is not silent,
+a question mark (?) is placed in VAR, OPTARG is unset, and a
+diagnostic message is printed.  If getopts is silent, then a
+colon (:) is placed in VAR and OPTARG is set to the option
+character found.
+
+Test that VAR is a valid variable name?
+
+"Whenever the shell is invoked, OPTIND shall be initialized to 1"
+*/
+	char cbuf[2];
+	const char *cp, *optstring, *var;
+	int c, n, exitcode, my_opterr;
+	unsigned count;
+
+	optstring = *++argv;
+	if (!optstring || !(var = *++argv)) {
+		bb_simple_error_msg("usage: getopts OPTSTRING VAR [ARGS]");
+		return EXIT_FAILURE;
+	}
+
+	if (argv[1])
+		argv[0] = G.global_argv[0]; /* for error messages in getopt() */
+	else
+		argv = G.global_argv;
+	cbuf[1] = '\0';
+
+	my_opterr = 0;
+	if (optstring[0] != ':') {
+		cp = get_local_var_value("OPTERR");
+		/* 0 if "OPTERR=0", 1 otherwise */
+		my_opterr = (!cp || NOT_LONE_CHAR(cp, '0'));
+	}
+
+	/* getopts stops on first non-option. Add "+" to force that */
+	/*if (optstring[0] != '+')*/ {
+		char *s = alloca(strlen(optstring) + 2);
+		sprintf(s, "+%s", optstring);
+		optstring = s;
+	}
+
+	/* Naively, now we should just
+	 *	cp = get_local_var_value("OPTIND");
+	 *	optind = cp ? atoi(cp) : 0;
+	 *	optarg = NULL;
+	 *	opterr = my_opterr;
+	 *	c = getopt(string_array_len(argv), argv, optstring);
+	 * and be done? Not so fast...
+	 * Unlike normal getopt() usage in C programs, here
+	 * each successive call will (usually) have the same argv[] CONTENTS,
+	 * but not the ADDRESSES. Worse yet, it's possible that between
+	 * invocations of "getopts", there will be calls to shell builtins
+	 * which use getopt() internally. Example:
+	 *	while getopts "abc" RES -a -bc -abc de; do
+	 *		unset -ff func
+	 *	done
+	 * This would not work correctly: getopt() call inside "unset"
+	 * modifies internal libc state which is tracking position in
+	 * multi-option strings ("-abc"). At best, it can skip options
+	 * or return the same option infinitely. With glibc implementation
+	 * of getopt(), it would use outright invalid pointers and return
+	 * garbage even _without_ "unset" mangling internal state.
+	 *
+	 * We resort to resetting getopt() state and calling it N times,
+	 * until we get Nth result (or failure).
+	 * (N == G.getopt_count is reset to 0 whenever OPTIND is [un]set).
+	 */
+	GETOPT_RESET();
+	count = 0;
+	n = string_array_len(argv);
+	do {
+		optarg = NULL;
+		opterr = (count < G.getopt_count) ? 0 : my_opterr;
+		c = getopt(n, argv, optstring);
+		if (c < 0)
+			break;
+		count++;
+	} while (count <= G.getopt_count);
+
+	/* Set OPTIND. Prevent resetting of the magic counter! */
+	set_local_var_from_halves("OPTIND", utoa(optind));
+	G.getopt_count = count; /* "next time, give me N+1'th result" */
+	GETOPT_RESET(); /* just in case */
+
+	/* Set OPTARG */
+	/* Always set or unset, never left as-is, even on exit/error:
+	 * "If no option was found, or if the option that was found
+	 * does not have an option-argument, OPTARG shall be unset."
+	 */
+	cp = optarg;
+	if (c == '?') {
+		/* If ":optstring" and unknown option is seen,
+		 * it is stored to OPTARG.
+		 */
+		if (optstring[1] == ':') {
+			cbuf[0] = optopt;
+			cp = cbuf;
+		}
+	}
+	if (cp)
+		set_local_var_from_halves("OPTARG", cp);
+	else
+		unset_local_var("OPTARG");
+
+	/* Convert -1 to "?" */
+	exitcode = EXIT_SUCCESS;
+	if (c < 0) { /* -1: end of options */
+		exitcode = EXIT_FAILURE;
+		c = '?';
+	}
+
+	/* Set VAR */
+	cbuf[0] = c;
+	set_local_var_from_halves(var, cbuf);
+
+	return exitcode;
+}
+#endif
+
+static int FAST_FUNC builtin_source(char **argv)
+{
+	char *arg_path, *filename;
+	HFILE *input;
+	save_arg_t sv;
+	char *args_need_save;
+#if ENABLE_HUSH_FUNCTIONS
+	smallint sv_flg;
+#endif
+
+	argv = skip_dash_dash(argv);
+	filename = argv[0];
+	if (!filename) {
+		/* bash says: "bash: .: filename argument required" */
+		return 2; /* bash compat */
+	}
+	arg_path = NULL;
+	if (!strchr(filename, '/')) {
+		arg_path = find_in_path(filename);
+		if (arg_path)
+			filename = arg_path;
+		else if (!ENABLE_HUSH_BASH_SOURCE_CURDIR) {
+			errno = ENOENT;
+			bb_simple_perror_msg(filename);
+			return EXIT_FAILURE;
+		}
+	}
+	input = hfopen(filename);
+	free(arg_path);
+	if (!input) {
+		bb_perror_msg("%s", filename);
+		/* POSIX: non-interactive shell should abort here,
+		 * not merely fail. So far no one complained :)
+		 */
+		return EXIT_FAILURE;
+	}
+
+#if ENABLE_HUSH_FUNCTIONS
+	sv_flg = G_flag_return_in_progress;
+	/* "we are inside sourced file, ok to use return" */
+	G_flag_return_in_progress = -1;
+#endif
+	args_need_save = argv[1]; /* used as a boolean variable */
+	if (args_need_save)
+		save_and_replace_G_args(&sv, argv);
+
+	/* "false; . ./empty_line; echo Zero:$?" should print 0 */
+	G.last_exitcode = 0;
+	parse_and_run_file(input);
+	hfclose(input);
+
+	if (args_need_save) /* can't use argv[1] instead: "shift" can mangle it */
+		restore_G_args(&sv, argv);
+#if ENABLE_HUSH_FUNCTIONS
+	G_flag_return_in_progress = sv_flg;
+#endif
+
+	return G.last_exitcode;
+}
+
+#if ENABLE_HUSH_TRAP
+static int FAST_FUNC builtin_trap(char **argv)
+{
+	int sig;
+	char *new_cmd;
+
+	if (!G_traps)
+		G_traps = xzalloc(sizeof(G_traps[0]) * NSIG);
+
+	argv++;
+	if (!*argv) {
+		int i;
+		/* No args: print all trapped */
+		for (i = 0; i < NSIG; ++i) {
+			if (G_traps[i]) {
+				printf("trap -- ");
+				print_escaped(G_traps[i]);
+				/* note: bash adds "SIG", but only if invoked
+				 * as "bash". If called as "sh", or if set -o posix,
+				 * then it prints short signal names.
+				 * We are printing short names: */
+				printf(" %s\n", get_signame(i));
+			}
+		}
+		/*fflush_all(); - done after each builtin anyway */
+		return EXIT_SUCCESS;
+	}
+
+	new_cmd = NULL;
+	/* If first arg is a number: reset all specified signals */
+	sig = bb_strtou(*argv, NULL, 10);
+	if (errno == 0) {
+		int ret;
+ process_sig_list:
+		ret = EXIT_SUCCESS;
+		while (*argv) {
+			sighandler_t handler;
+
+			sig = get_signum(*argv++);
+			if (sig < 0) {
+				ret = EXIT_FAILURE;
+				/* Mimic bash message exactly */
+				bb_error_msg("trap: %s: invalid signal specification", argv[-1]);
+				continue;
+			}
+
+			free(G_traps[sig]);
+			G_traps[sig] = xstrdup(new_cmd);
+
+			debug_printf("trap: setting SIG%s (%i) to '%s'\n",
+				get_signame(sig), sig, G_traps[sig]);
+
+			/* There is no signal for 0 (EXIT) */
+			if (sig == 0)
+				continue;
+
+			if (new_cmd)
+				handler = (new_cmd[0] ? record_pending_signo : SIG_IGN);
+			else
+				/* We are removing trap handler */
+				handler = pick_sighandler(sig);
+			install_sighandler(sig, handler);
+		}
+		return ret;
+	}
+
+	if (!argv[1]) { /* no second arg */
+		bb_simple_error_msg("trap: invalid arguments");
+		return EXIT_FAILURE;
+	}
+
+	/* First arg is "-": reset all specified to default */
+	/* First arg is "--": skip it, the rest is "handler SIGs..." */
+	/* Everything else: set arg as signal handler
+	 * (includes "" case, which ignores signal) */
+	if (argv[0][0] == '-') {
+		if (argv[0][1] == '\0') { /* "-" */
+			/* new_cmd remains NULL: "reset these sigs" */
+			goto reset_traps;
+		}
+		if (argv[0][1] == '-' && argv[0][2] == '\0') { /* "--" */
+			argv++;
+		}
+		/* else: "-something", no special meaning */
+	}
+	new_cmd = *argv;
+ reset_traps:
+	argv++;
+	goto process_sig_list;
+}
+#endif
+
+#if ENABLE_HUSH_JOB
+static struct pipe *parse_jobspec(const char *str)
+{
+	struct pipe *pi;
+	unsigned jobnum;
+
+	if (sscanf(str, "%%%u", &jobnum) != 1) {
+		if (str[0] != '%'
+		 || (str[1] != '%' && str[1] != '+' && str[1] != '\0')
+		) {
+			bb_error_msg("bad argument '%s'", str);
+			return NULL;
+		}
+		/* It is "%%", "%+" or "%" - current job */
+		jobnum = G.last_jobid;
+		if (jobnum == 0) {
+			bb_simple_error_msg("no current job");
+			return NULL;
+		}
+	}
+	for (pi = G.job_list; pi; pi = pi->next) {
+		if (pi->jobid == jobnum) {
+			return pi;
+		}
+	}
+	bb_error_msg("%u: no such job", jobnum);
+	return NULL;
+}
+
+static int FAST_FUNC builtin_jobs(char **argv UNUSED_PARAM)
+{
+	struct pipe *job;
+	const char *status_string;
+
+	checkjobs(NULL, 0 /*(no pid to wait for)*/);
+	for (job = G.job_list; job; job = job->next) {
+		if (job->alive_cmds == job->stopped_cmds)
+			status_string = "Stopped";
+		else
+			status_string = "Running";
+
+		printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->cmdtext);
+	}
+
+	clean_up_last_dead_job();
+
+	return EXIT_SUCCESS;
+}
+
+/* built-in 'fg' and 'bg' handler */
+static int FAST_FUNC builtin_fg_bg(char **argv)
+{
+	int i;
+	struct pipe *pi;
+
+	if (!G_interactive_fd)
+		return EXIT_FAILURE;
+
+	/* If they gave us no args, assume they want the last backgrounded task */
+	if (!argv[1]) {
+		for (pi = G.job_list; pi; pi = pi->next) {
+			if (pi->jobid == G.last_jobid) {
+				goto found;
+			}
+		}
+		bb_error_msg("%s: no current job", argv[0]);
+		return EXIT_FAILURE;
+	}
+
+	pi = parse_jobspec(argv[1]);
+	if (!pi)
+		return EXIT_FAILURE;
+ found:
+	/* TODO: bash prints a string representation
+	 * of job being foregrounded (like "sleep 1 | cat") */
+	if (argv[0][0] == 'f' && G_saved_tty_pgrp) {
+		/* Put the job into the foreground.  */
+		tcsetpgrp(G_interactive_fd, pi->pgrp);
+	}
+
+	/* Restart the processes in the job */
+	debug_printf_jobs("reviving %d procs, pgrp %d\n", pi->num_cmds, pi->pgrp);
+	for (i = 0; i < pi->num_cmds; i++) {
+		debug_printf_jobs("reviving pid %d\n", pi->cmds[i].pid);
+	}
+	pi->stopped_cmds = 0;
+
+	i = kill(- pi->pgrp, SIGCONT);
+	if (i < 0) {
+		if (errno == ESRCH) {
+			delete_finished_job(pi);
+			return EXIT_SUCCESS;
+		}
+		bb_simple_perror_msg("kill (SIGCONT)");
+	}
+
+	if (argv[0][0] == 'f') {
+		remove_job_from_table(pi); /* FG job shouldn't be in job table */
+		return checkjobs_and_fg_shell(pi);
+	}
+	return EXIT_SUCCESS;
+}
+#endif
+
+#if ENABLE_HUSH_KILL
+static int FAST_FUNC builtin_kill(char **argv)
+{
+	int ret = 0;
+
+# if ENABLE_HUSH_JOB
+	if (argv[1] && strcmp(argv[1], "-l") != 0) {
+		int i = 1;
+
+		do {
+			struct pipe *pi;
+			char *dst;
+			int j, n;
+
+			if (argv[i][0] != '%')
+				continue;
+			/*
+			 * "kill %N" - job kill
+			 * Converting to pgrp / pid kill
+			 */
+			pi = parse_jobspec(argv[i]);
+			if (!pi) {
+				/* Eat bad jobspec */
+				j = i;
+				do {
+					j++;
+					argv[j - 1] = argv[j];
+				} while (argv[j]);
+				ret = 1;
+				i--;
+				continue;
+			}
+			/*
+			 * In jobs started under job control, we signal
+			 * entire process group by kill -PGRP_ID.
+			 * This happens, f.e., in interactive shell.
+			 *
+			 * Otherwise, we signal each child via
+			 * kill PID1 PID2 PID3.
+			 * Testcases:
+			 * sh -c 'sleep 1|sleep 1 & kill %1'
+			 * sh -c 'true|sleep 2 & sleep 1; kill %1'
+			 * sh -c 'true|sleep 1 & sleep 2; kill %1'
+			 */
+			n = G_interactive_fd ? 1 : pi->num_cmds;
+			dst = alloca(n * sizeof(int)*4);
+			argv[i] = dst;
+			if (G_interactive_fd)
+				dst += sprintf(dst, " -%u", (int)pi->pgrp);
+			else for (j = 0; j < n; j++) {
+				struct command *cmd = &pi->cmds[j];
+				/* Skip exited members of the job */
+				if (cmd->pid == 0)
+					continue;
+				/*
+				 * kill_main has matching code to expect
+				 * leading space. Needed to not confuse
+				 * negative pids with "kill -SIGNAL_NO" syntax
+				 */
+				dst += sprintf(dst, " %u", (int)cmd->pid);
+			}
+			*dst = '\0';
+		} while (argv[++i]);
+	}
+# endif
+
+	if (argv[1] || ret == 0) {
+		ret = run_applet_main(argv, kill_main);
+	}
+	/* else: ret = 1, "kill %bad_jobspec" case */
+	return ret;
+}
+#endif
+
+#if ENABLE_HUSH_WAIT
+/* http://www.opengroup.org/onlinepubs/9699919799/utilities/wait.html */
+# if !ENABLE_HUSH_JOB
+#  define wait_for_child_or_signal(pipe,pid) wait_for_child_or_signal(pid)
+# endif
+static int wait_for_child_or_signal(struct pipe *waitfor_pipe, pid_t waitfor_pid)
+{
+	int ret = 0;
+	for (;;) {
+		int sig;
+		sigset_t oldset;
+
+		if (!sigisemptyset(&G.pending_set))
+			goto check_sig;
+
+		/* waitpid is not interruptible by SA_RESTARTed
+		 * signals which we use. Thus, this ugly dance:
+		 */
+
+		/* Make sure possible SIGCHLD is stored in kernel's
+		 * pending signal mask before we call waitpid.
+		 * Or else we may race with SIGCHLD, lose it,
+		 * and get stuck in sigsuspend...
+		 */
+		sigfillset(&oldset); /* block all signals, remember old set */
+		sigprocmask2(SIG_SETMASK, &oldset);
+
+		if (!sigisemptyset(&G.pending_set)) {
+			/* Crap! we raced with some signal! */
+			goto restore;
+		}
+
+		/*errno = 0; - checkjobs does this */
+/* Can't pass waitfor_pipe into checkjobs(): it won't be interruptible */
+		ret = checkjobs(NULL, waitfor_pid); /* waitpid(WNOHANG) inside */
+		debug_printf_exec("checkjobs:%d\n", ret);
+# if ENABLE_HUSH_JOB
+		if (waitfor_pipe) {
+			int rcode = job_exited_or_stopped(waitfor_pipe);
+			debug_printf_exec("job_exited_or_stopped:%d\n", rcode);
+			if (rcode >= 0) {
+				ret = rcode;
+				sigprocmask(SIG_SETMASK, &oldset, NULL);
+				break;
+			}
+		}
+# endif
+		/* if ECHILD, there are no children (ret is -1 or 0) */
+		/* if ret == 0, no children changed state */
+		/* if ret != 0, it's exitcode+1 of exited waitfor_pid child */
+		if (errno == ECHILD || ret) {
+			ret--;
+			if (ret < 0) /* if ECHILD, may need to fix "ret" */
+				ret = 0;
+# if ENABLE_HUSH_BASH_COMPAT
+			if (waitfor_pid == -1 && errno == ECHILD) {
+				/* exitcode of "wait -n" with no children is 127, not 0 */
+				ret = 127;
+			}
+# endif
+			sigprocmask(SIG_SETMASK, &oldset, NULL);
+			break;
+		}
+		/* Wait for SIGCHLD or any other signal */
+		/* It is vitally important for sigsuspend that SIGCHLD has non-DFL handler! */
+		/* Note: sigsuspend invokes signal handler */
+		sigsuspend(&oldset);
+		/* ^^^ add "sigdelset(&oldset, SIGCHLD)" before sigsuspend
+		 * to make sure SIGCHLD is not masked off?
+		 * It was reported that this:
+		 *	fn() { : | return; }
+		 *	shopt -s lastpipe
+		 *	fn
+		 *	exec hush SCRIPT
+		 * under bash 4.4.23 runs SCRIPT with SIGCHLD masked,
+		 * making "wait" commands in SCRIPT block forever.
+		 */
+ restore:
+		sigprocmask(SIG_SETMASK, &oldset, NULL);
+ check_sig:
+		/* So, did we get a signal? */
+		sig = check_and_run_traps();
+		if (sig /*&& sig != SIGCHLD - always true */) {
+			/* Do this for any (non-ignored) signal, not only for ^C */
+			ret = 128 | sig;
+			break;
+		}
+		/* SIGCHLD, or no signal, or ignored one, such as SIGQUIT. Repeat */
+	}
+	return ret;
+}
+
+static int FAST_FUNC builtin_wait(char **argv)
+{
+	int ret;
+	int status;
+
+	argv = skip_dash_dash(argv);
+# if ENABLE_HUSH_BASH_COMPAT
+	if (argv[0] && strcmp(argv[0], "-n") == 0) {
+		/* wait -n */
+		/* (bash accepts "wait -n PID" too and ignores PID) */
+		G.dead_job_exitcode = -1;
+		return wait_for_child_or_signal(NULL, -1 /*no job, wait for one job*/);
+	}
+# endif
+	if (argv[0] == NULL) {
+		/* Don't care about wait results */
+		/* Note 1: must wait until there are no more children */
+		/* Note 2: must be interruptible */
+		/* Examples:
+		 * $ sleep 3 & sleep 6 & wait
+		 * [1] 30934 sleep 3
+		 * [2] 30935 sleep 6
+		 * [1] Done                   sleep 3
+		 * [2] Done                   sleep 6
+		 * $ sleep 3 & sleep 6 & wait
+		 * [1] 30936 sleep 3
+		 * [2] 30937 sleep 6
+		 * [1] Done                   sleep 3
+		 * ^C <-- after ~4 sec from keyboard
+		 * $
+		 */
+		return wait_for_child_or_signal(NULL, 0 /*no job and no pid to wait for*/);
+	}
+
+	do {
+		pid_t pid = bb_strtou(*argv, NULL, 10);
+		if (errno || pid <= 0) {
+# if ENABLE_HUSH_JOB
+			if (argv[0][0] == '%') {
+				struct pipe *wait_pipe;
+				ret = 127; /* bash compat for bad jobspecs */
+				wait_pipe = parse_jobspec(*argv);
+				if (wait_pipe) {
+					ret = job_exited_or_stopped(wait_pipe);
+					if (ret < 0) {
+						ret = wait_for_child_or_signal(wait_pipe, 0);
+					} else {
+						/* waiting on "last dead job" removes it */
+						clean_up_last_dead_job();
+					}
+				}
+				/* else: parse_jobspec() already emitted error msg */
+				continue;
+			}
+# endif
+			/* mimic bash message */
+			bb_error_msg("wait: '%s': not a pid or valid job spec", *argv);
+			ret = EXIT_FAILURE;
+			continue; /* bash checks all argv[] */
+		}
+
+		/* Do we have such child? */
+		ret = waitpid(pid, &status, WNOHANG);
+		if (ret < 0) {
+			/* No */
+			ret = 127;
+			if (errno == ECHILD) {
+				if (pid == G.last_bg_pid) {
+					/* "wait $!" but last bg task has already exited. Try:
+					 * (sleep 1; exit 3) & sleep 2; echo $?; wait $!; echo $?
+					 * In bash it prints exitcode 0, then 3.
+					 * In dash, it is 127.
+					 */
+					ret = G.last_bg_pid_exitcode;
+				} else {
+					/* Example: "wait 1". mimic bash message */
+					bb_error_msg("wait: pid %u is not a child of this shell", (unsigned)pid);
+				}
+			} else {
+				/* ??? */
+				bb_perror_msg("wait %s", *argv);
+			}
+			continue; /* bash checks all argv[] */
+		}
+		if (ret == 0) {
+			/* Yes, and it still runs */
+			ret = wait_for_child_or_signal(NULL, pid);
+		} else {
+			/* Yes, and it just exited */
+			process_wait_result(NULL, pid, status);
+			ret = WEXITSTATUS(status);
+			if (WIFSIGNALED(status))
+				ret = 128 | WTERMSIG(status);
+		}
+	} while (*++argv);
+
+	return ret;
+}
+#endif
+
+#if ENABLE_HUSH_LOOPS || ENABLE_HUSH_FUNCTIONS
+static unsigned parse_numeric_argv1(char **argv, unsigned def, unsigned def_min)
+{
+	if (argv[1]) {
+		def = bb_strtou(argv[1], NULL, 10);
+		if (errno || def < def_min || argv[2]) {
+			bb_error_msg("%s: bad arguments", argv[0]);
+			def = UINT_MAX;
+		}
+	}
+	return def;
+}
+#endif
+
+#if ENABLE_HUSH_LOOPS
+static int FAST_FUNC builtin_break(char **argv)
+{
+	unsigned depth;
+	if (G.depth_of_loop == 0) {
+		bb_error_msg("%s: only meaningful in a loop", argv[0]);
+		/* if we came from builtin_continue(), need to undo "= 1" */
+		G.flag_break_continue = 0;
+		return EXIT_SUCCESS; /* bash compat */
+	}
+	G.flag_break_continue++; /* BC_BREAK = 1, or BC_CONTINUE = 2 */
+
+	G.depth_break_continue = depth = parse_numeric_argv1(argv, 1, 1);
+	if (depth == UINT_MAX)
+		G.flag_break_continue = BC_BREAK;
+	if (G.depth_of_loop < depth)
+		G.depth_break_continue = G.depth_of_loop;
+
+	return EXIT_SUCCESS;
+}
+
+static int FAST_FUNC builtin_continue(char **argv)
+{
+	G.flag_break_continue = 1; /* BC_CONTINUE = 2 = 1+1 */
+	return builtin_break(argv);
+}
+#endif
+
+#if ENABLE_HUSH_FUNCTIONS
+static int FAST_FUNC builtin_return(char **argv)
+{
+	int rc;
+
+	if (G_flag_return_in_progress != -1) {
+		bb_error_msg("%s: not in a function or sourced script", argv[0]);
+		return EXIT_FAILURE; /* bash compat */
+	}
+
+	G_flag_return_in_progress = 1;
+
+	/* bash:
+	 * out of range: wraps around at 256, does not error out
+	 * non-numeric param:
+	 * f() { false; return qwe; }; f; echo $?
+	 * bash: return: qwe: numeric argument required  <== we do this
+	 * 255  <== we also do this
+	 */
+	rc = parse_numeric_argv1(argv, G.last_exitcode, 0);
+# if ENABLE_HUSH_TRAP
+	if (argv[1]) { /* "return ARG" inside a running trap sets $? */
+		debug_printf_exec("G.return_exitcode=%d\n", rc);
+		G.return_exitcode = rc;
+	}
+# endif
+	return rc;
+}
+#endif
+
+#if ENABLE_HUSH_TIMES
+static int FAST_FUNC builtin_times(char **argv UNUSED_PARAM)
+{
+	static const uint8_t times_tbl[] ALIGN1 = {
+		' ',  offsetof(struct tms, tms_utime),
+		'\n', offsetof(struct tms, tms_stime),
+		' ',  offsetof(struct tms, tms_cutime),
+		'\n', offsetof(struct tms, tms_cstime),
+		0
+	};
+	const uint8_t *p;
+	unsigned clk_tck;
+	struct tms buf;
+
+	clk_tck = bb_clk_tck();
+
+	times(&buf);
+	p = times_tbl;
+	do {
+		unsigned sec, frac;
+		unsigned long t;
+		t = *(clock_t *)(((char *) &buf) + p[1]);
+		sec = t / clk_tck;
+		frac = t % clk_tck;
+		printf("%um%u.%03us%c",
+			sec / 60, sec % 60,
+			(frac * 1000) / clk_tck,
+			p[0]);
+		p += 2;
+	} while (*p);
+
+	return EXIT_SUCCESS;
+}
+#endif
+
+#if ENABLE_HUSH_MEMLEAK
+static int FAST_FUNC builtin_memleak(char **argv UNUSED_PARAM)
+{
+	void *p;
+	unsigned long l;
+
+# ifdef M_TRIM_THRESHOLD
+	/* Optional. Reduces probability of false positives */
+	malloc_trim(0);
+# endif
+	/* Crude attempt to find where "free memory" starts,
+	 * sans fragmentation. */
+	p = malloc(240);
+	l = (unsigned long)p;
+	free(p);
+	p = malloc(3400);
+	if (l < (unsigned long)p) l = (unsigned long)p;
+	free(p);
+
+
+# if 0  /* debug */
+	{
+		struct mallinfo mi = mallinfo();
+		printf("top alloc:0x%lx malloced:%d+%d=%d\n", l,
+			mi.arena, mi.hblkhd, mi.arena + mi.hblkhd);
+	}
+# endif
+
+	if (!G.memleak_value)
+		G.memleak_value = l;
+
+	l -= G.memleak_value;
+	if ((long)l < 0)
+		l = 0;
+	l /= 1024;
+	if (l > 127)
+		l = 127;
+
+	/* Exitcode is "how many kilobytes we leaked since 1st call" */
+	return l;
+}
+#endif
-- 
2.25.1



More information about the U-Boot mailing list