[PATCH v3 4/6] cmd: setexpr: add format string handling
Roland Gaudig
roland.gaudig-oss at weidmueller.com
Fri Jul 23 14:29:21 CEST 2021
From: Roland Gaudig <roland.gaudig at weidmueller.com>
Add format string handling operator to the setexpr command.
It allows to use C or Bash like format string expressions to be
evaluated with the result being stored inside the environment variable
name.
setexpr <name> fmt <format> [value]...
The following example
setexpr foo fmt "%d, 0x%x" 0x100 ff
will result in $foo being set to "256, 0xff".
Signed-off-by: Roland Gaudig <roland.gaudig at weidmueller.com>
---
(no changes since v1)
MAINTAINERS | 5 +
cmd/Kconfig | 8 +
cmd/Makefile | 1 +
cmd/printf.c | 419 +++++++++++++++++++++++++++++---------------------
cmd/printf.h | 8 +
cmd/setexpr.c | 37 ++++-
6 files changed, 300 insertions(+), 178 deletions(-)
create mode 100644 cmd/printf.h
diff --git a/MAINTAINERS b/MAINTAINERS
index a6b49b54b9..fe53698878 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1049,6 +1049,11 @@ F: arch/sandbox/
F: doc/arch/sandbox.rst
F: include/dt-bindings/*/sandbox*.h
+SETEXPR
+M: Roland Gaudig <roland.gaudig at weidmueller.com>
+S: Maintained
+F: cmd/printf.c
+
SH
M: Marek Vasut <marek.vasut+renesas at gmail.com>
M: Nobuhiro Iwamatsu <iwamatsu at nigauri.org>
diff --git a/cmd/Kconfig b/cmd/Kconfig
index e40d390f88..f1bcf9ebde 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -1414,6 +1414,14 @@ config CMD_SETEXPR
Also supports loading the value at a memory location into a variable.
If CONFIG_REGEX is enabled, setexpr also supports a gsub function.
+config CMD_SETEXPR_FMT
+ bool "setexpr_fmt"
+ default n
+ depends on CMD_SETEXPR
+ help
+ Evaluate format string expression and store result in an environment
+ variable.
+
endmenu
menu "Android support commands"
diff --git a/cmd/Makefile b/cmd/Makefile
index 9d10e07f0e..ed3669411e 100644
--- a/cmd/Makefile
+++ b/cmd/Makefile
@@ -141,6 +141,7 @@ obj-$(CONFIG_CMD_SF) += sf.o
obj-$(CONFIG_CMD_SCSI) += scsi.o disk.o
obj-$(CONFIG_CMD_SHA1SUM) += sha1sum.o
obj-$(CONFIG_CMD_SETEXPR) += setexpr.o
+obj-$(CONFIG_CMD_SETEXPR_FMT) += printf.o
obj-$(CONFIG_CMD_SPI) += spi.o
obj-$(CONFIG_CMD_STRINGS) += strings.o
obj-$(CONFIG_CMD_SMC) += smccc.o
diff --git a/cmd/printf.c b/cmd/printf.c
index 337ab8ce5d..e024676743 100644
--- a/cmd/printf.c
+++ b/cmd/printf.c
@@ -1,12 +1,21 @@
-/* vi: set sw=4 ts=4: */
+// SPDX-License-Identifier: GPL-2.0+
/*
- * printf - format and print data
+ * Copyright (C) 2021 Weidmüller Interface GmbH & Co. KG
+ * Roland Gaudig <roland.gaudig at weidmueller.com>
*
* Copyright 1999 Dave Cinege
* Portions copyright (C) 1990-1996 Free Software Foundation, Inc.
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
+/*
+ * This file provides a shell printf like format string expansion as required
+ * for the setexpr <name> fmt <format> <value> command.
+ * This source file was mostly taken from the BusyBox project (www.busybox.net)
+ * In contrast to the original sources the output is not written to stdout
+ * anymore but into a char array, which can be used as input for the env_set()
+ * function.
+ */
/* Usage: printf format [argument...]
*
* A front end to the printf function that lets it be used from the shell.
@@ -59,8 +68,6 @@
//usage: "$ printf \"Val=%d\\n\" 5\n"
//usage: "Val=5\n"
-#include "libbb.h"
-
/* A note on bad input: neither bash 3.2 nor coreutils 6.10 stop on it.
* They report it:
* bash: printf: XXX: invalid number
@@ -77,22 +84,97 @@
* We try to be compatible.
*/
-typedef void FAST_FUNC (*converter)(const char *arg, void *result);
+#include <common.h>
+#include <ctype.h>
+#include <errno.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
#define WANT_HEX_ESCAPES 0
+#define PRINT_CONVERSION_ERROR 1
+#define PRINT_TRUNCATED_ERROR 2
+#define PRINT_SIZE_ERROR 4
+
+struct print_inf {
+ char *str;
+ size_t size;
+ size_t offset;
+ unsigned int error;
+};
+
+typedef void (*converter)(const char *arg, void *result);
+
+/**
+ * printf_str() - print formatted into char array with length checks
+ *
+ * This function povides a printf like function for printing into a char array
+ * with checking the boundaries.
+ * Unlike snprintf, all checks are performed inside this function and status
+ * reports are stored inside the print_inf struct. That way, this function can
+ * be used almost as drop-in replacement without needing much code changes.
+ * Unlike snprintf errors are not reported by return value, but inside the
+ * error member of struct print_inf. The output stored inside the struct
+ * print_inf str member shall only be used when the error member is 0.
+ *
+ * @inf: Info structure for print operation
+ * @char: format string with optional arguments
+ */
+static void printf_str(struct print_inf *inf, char *format, ...)
+{
+ va_list args;
+ int i;
-/* Usual "this only works for ascii compatible encodings" disclaimer. */
-#undef _tolower
-#define _tolower(X) ((X)|((char) 0x20))
+ if (!inf)
+ return;
+
+ /* Do not write anything if previous error is pending */
+ if (inf->error)
+ return;
+
+ /* Check if end of receiving buffer is already reached */
+ if (inf->offset >= inf->size) {
+ inf->error |= PRINT_SIZE_ERROR;
+ return;
+ }
+
+ size_t remaining = inf->size - inf->offset;
+
+ va_start(args, format);
+ i = vsnprintf(inf->str + inf->offset, remaining, format, args);
+ va_end(args);
+
+ if (i >= remaining)
+ inf->error |= PRINT_TRUNCATED_ERROR;
+ else if (i < 0)
+ inf->error |= PRINT_CONVERSION_ERROR;
+ else
+ inf->offset += i;
+}
+
+/**
+ * putchar_str() - Print single character into char array with length checks
+ *
+ * This function provices a putchar like function, which stores the output
+ * into a char array with checking boundaries.
+ *
+ * @inf: Info structure for print operation
+ * @char: Single character to be printed
+ */
+static void putchar_str(struct print_inf *inf, char c)
+{
+ printf_str(inf, "%c", c);
+}
-char FAST_FUNC bb_process_escape_sequence(const char **ptr)
+static char process_escape_sequence(const char **ptr)
{
const char *q;
- unsigned num_digits;
- unsigned n;
- unsigned base;
+ unsigned int num_digits;
+ unsigned int n;
+ unsigned int base;
- num_digits = n = 0;
+ num_digits = 0;
+ n = 0;
base = 8;
q = *ptr;
@@ -104,13 +186,14 @@ char FAST_FUNC bb_process_escape_sequence(const char **ptr)
/* bash requires leading 0 in octal escapes:
* \02 works, \2 does not (prints \ and 2).
- * We treat \2 as a valid octal escape sequence. */
+ * We treat \2 as a valid octal escape sequence.
+ */
do {
- unsigned r;
- unsigned d = (unsigned char)(*q) - '0';
+ unsigned int r;
+ unsigned int d = (unsigned char)(*q) - '0';
#if WANT_HEX_ESCAPES
if (d >= 10) {
- d = (unsigned char)_tolower(*q) - 'a';
+ d = (unsigned char)tolower(*q) - 'a';
//d += 10;
/* The above would map 'A'-'F' and 'a'-'f' to 10-15,
* however, some chars like '@' would map to 9 < base.
@@ -125,7 +208,8 @@ char FAST_FUNC bb_process_escape_sequence(const char **ptr)
--num_digits;
if (num_digits == 0) {
/* \x<bad_char>: return '\',
- * leave ptr pointing to x */
+ * leave ptr pointing to x
+ */
return '\\';
}
}
@@ -133,9 +217,8 @@ char FAST_FUNC bb_process_escape_sequence(const char **ptr)
}
r = n * base + d;
- if (r > UCHAR_MAX) {
+ if (r > 255)
break;
- }
n = r;
++q;
@@ -143,17 +226,20 @@ char FAST_FUNC bb_process_escape_sequence(const char **ptr)
if (num_digits == 0) {
/* Not octal or hex escape sequence.
- * Is it one-letter one? */
-
+ * Is it one-letter one?
+ */
/* bash builtin "echo -e '\ec'" interprets \e as ESC,
* but coreutils "/bin/echo -e '\ec'" does not.
* Manpages tend to support coreutils way.
- * Update: coreutils added support for \e on 28 Oct 2009. */
- static const char charmap[] ALIGN1 = {
+ * Update: coreutils added support for \e on 28 Oct 2009.
+ */
+ static const char charmap[] = {
'a', 'b', 'e', 'f', 'n', 'r', 't', 'v', '\\', '\0',
'\a', '\b', 27, '\f', '\n', '\r', '\t', '\v', '\\', '\\',
};
+
const char *p = charmap;
+
do {
if (*p == *q) {
q++;
@@ -163,16 +249,17 @@ char FAST_FUNC bb_process_escape_sequence(const char **ptr)
/* p points to found escape char or NUL,
* advance it and find what it translates to.
* Note that \NUL and unrecognized sequence \z return '\'
- * and leave ptr pointing to NUL or z. */
+ * and leave ptr pointing to NUL or z.
+ */
n = p[sizeof(charmap) / 2];
}
*ptr = q;
- return (char) n;
+ return (char)n;
}
-char* FAST_FUNC skip_whitespace(const char *s)
+static char *skip_whitespace(const char *s)
{
/* In POSIX/C locale (the only locale we care about: do we REALLY want
* to allow Unicode whitespace in, say, .conf files? nuts!)
@@ -183,11 +270,11 @@ char* FAST_FUNC skip_whitespace(const char *s)
while (*s == ' ' || (unsigned char)(*s - 9) <= (13 - 9))
s++;
- return (char *) s;
+ return (char *)s;
}
/* Like strcpy but can copy overlapping strings. */
-void FAST_FUNC overlapping_strcpy(char *dst, const char *src)
+static void overlapping_strcpy(char *dst, const char *src)
{
/* Cheap optimization for dst == src case -
* better to have it here than in many callers.
@@ -202,80 +289,72 @@ void FAST_FUNC overlapping_strcpy(char *dst, const char *src)
static int multiconvert(const char *arg, void *result, converter convert)
{
- if (*arg == '"' || *arg == '\'') {
- arg = utoa((unsigned char)arg[1]);
- }
- errno = 0;
+ if (*arg == '"' || *arg == '\'')
+ sprintf((char *)arg + strlen(arg), "%u", (unsigned char)arg[1]);
+ //errno = 0;
convert(arg, result);
- if (errno) {
- bb_error_msg("invalid number '%s'", arg);
- return 1;
- }
+ /* Unlike their Posix counterparts, simple_strtoll and
+ * simple_strtoull do not set errno
+ *
+ * if (errno) {
+ * printf("error invalid number '%s'", arg);
+ * return 1;
+ * }
+ */
return 0;
}
-static void FAST_FUNC conv_strtoull(const char *arg, void *result)
+static void conv_strtoull(const char *arg, void *result)
{
- /* Allow leading '+' - bb_strtoull() by itself does not allow it,
- * and probably shouldn't (other callers might require purely numeric
- * inputs to be allowed.
- */
- if (arg[0] == '+')
- arg++;
- *(unsigned long long*)result = bb_strtoull(arg, NULL, 0);
/* both coreutils 6.10 and bash 3.2:
* $ printf '%x\n' -2
* fffffffffffffffe
* Mimic that:
*/
- if (errno) {
- *(unsigned long long*)result = bb_strtoll(arg, NULL, 0);
+ if (arg[0] == '-') {
+ *(unsigned long long *)result = simple_strtoll(arg, NULL, 16);
+ return;
}
-}
-static void FAST_FUNC conv_strtoll(const char *arg, void *result)
-{
+ /* Allow leading '+' - simple_strtoull() by itself does not allow it,
+ * and probably shouldn't (other callers might require purely numeric
+ * inputs to be allowed.
+ */
if (arg[0] == '+')
arg++;
- *(long long*)result = bb_strtoll(arg, NULL, 0);
+ *(unsigned long long *)result = simple_strtoull(arg, NULL, 16);
}
-static void FAST_FUNC conv_strtod(const char *arg, void *result)
+
+static void conv_strtoll(const char *arg, void *result)
{
- char *end;
- /* Well, this one allows leading whitespace... so what? */
- /* What I like much less is that "-" accepted too! :( */
- *(double*)result = strtod(arg, &end);
- if (end[0]) {
- errno = ERANGE;
- *(double*)result = 0;
- }
+ if (arg[0] == '+')
+ arg++;
+ *(long long *)result = simple_strtoll(arg, NULL, 16);
}
/* Callers should check errno to detect errors */
static unsigned long long my_xstrtoull(const char *arg)
{
unsigned long long result;
+
if (multiconvert(arg, &result, conv_strtoull))
result = 0;
return result;
}
+
static long long my_xstrtoll(const char *arg)
{
long long result;
+
if (multiconvert(arg, &result, conv_strtoll))
result = 0;
return result;
}
-static double my_xstrtod(const char *arg)
-{
- double result;
- multiconvert(arg, &result, conv_strtod);
- return result;
-}
/* Handles %b; return 1 if output is to be short-circuited by \c */
-static int print_esc_string(const char *str)
+static int print_esc_string(struct print_inf *inf, const char *str)
{
char c;
+
while ((c = *str) != '\0') {
str++;
if (c == '\\') {
@@ -285,30 +364,30 @@ static int print_esc_string(const char *str)
/* 2nd char is 0..7: skip leading '0' */
str++;
}
- }
- else if (*str == 'c') {
+ } else if (*str == 'c') {
return 1;
}
{
/* optimization: don't force arg to be on-stack,
- * use another variable for that. */
+ * use another variable for that.
+ */
const char *z = str;
- c = bb_process_escape_sequence(&z);
+
+ c = process_escape_sequence(&z);
str = z;
}
}
- putchar(c);
+ putchar_str(inf, c);
}
return 0;
}
-static void print_direc(char *format, unsigned fmt_length,
- int field_width, int precision,
- const char *argument)
+static void print_direc(struct print_inf *inf, char *format, unsigned int fmt_length,
+ int field_width, int precision,
+ const char *argument)
{
long long llv;
- double dv;
char saved;
char *have_prec, *have_width;
@@ -325,7 +404,7 @@ static void print_direc(char *format, unsigned fmt_length,
switch (format[fmt_length - 1]) {
case 'c':
- printf(format, *argument);
+ printf_str(inf, format, *argument);
break;
case 'd':
case 'i':
@@ -333,14 +412,14 @@ static void print_direc(char *format, unsigned fmt_length,
print_long:
if (!have_width) {
if (!have_prec)
- printf(format, llv);
+ printf_str(inf, format, llv);
else
- printf(format, precision, llv);
+ printf_str(inf, format, precision, llv);
} else {
if (!have_prec)
- printf(format, field_width, llv);
+ printf_str(inf, format, field_width, llv);
else
- printf(format, field_width, precision, llv);
+ printf_str(inf, format, field_width, precision, llv);
}
break;
case 'o':
@@ -357,37 +436,25 @@ static void print_direc(char *format, unsigned fmt_length,
goto print_long;
} else {
/* Hope compiler will optimize it out by moving call
- * instruction after the ifs... */
+ * instruction after the ifs...
+ */
if (!have_width) {
if (!have_prec)
- printf(format, argument, /*unused:*/ argument, argument);
+ printf_str(inf, format, argument,
+ /*unused:*/ argument, argument);
else
- printf(format, precision, argument, /*unused:*/ argument);
+ printf_str(inf, format, precision,
+ argument, /*unused:*/ argument);
} else {
if (!have_prec)
- printf(format, field_width, argument, /*unused:*/ argument);
+ printf_str(inf, format, field_width,
+ argument, /*unused:*/ argument);
else
- printf(format, field_width, precision, argument);
+ printf_str(inf, format, field_width,
+ precision, argument);
}
break;
}
- case 'f':
- case 'e':
- case 'E':
- case 'g':
- case 'G':
- dv = my_xstrtod(argument);
- if (!have_width) {
- if (!have_prec)
- printf(format, dv);
- else
- printf(format, precision, dv);
- } else {
- if (!have_prec)
- printf(format, field_width, dv);
- else
- printf(format, field_width, precision, dv);
- }
break;
} /* switch */
@@ -397,22 +464,27 @@ static void print_direc(char *format, unsigned fmt_length,
/* Handle params for "%*.*f". Negative numbers are ok (compat). */
static int get_width_prec(const char *str)
{
- int v = bb_strtoi(str, NULL, 10);
- if (errno) {
- bb_error_msg("invalid number '%s'", str);
- v = 0;
- }
- return v;
+ long v = simple_strtol(str, NULL, 10);
+
+ /* Unlike its Posix counterpart, simple_strtol does not set errno
+ *
+ * if (errno) {
+ * printf("error invalid number '%s'", str);
+ * v = 0;
+ * }
+ */
+ return (int)v;
}
/* Print the text in FORMAT, using ARGV for arguments to any '%' directives.
- Return advanced ARGV. */
-static char **print_formatted(char *f, char **argv, int *conv_err)
+ * Return advanced ARGV.
+ */
+static char **print_formatted(struct print_inf *inf, char *f, char **argv, int *conv_err)
{
- char *direc_start; /* Start of % directive. */
- unsigned direc_length; /* Length of % directive. */
- int field_width; /* Arg to first '*' */
- int precision; /* Arg to second '*' */
+ char *direc_start; /* Start of % directive. */
+ unsigned int direc_length; /* Length of % directive. */
+ int field_width; /* Arg to first '*' */
+ int precision; /* Arg to second '*' */
char **saved_argv = argv;
for (; *f; ++f) {
@@ -420,14 +492,15 @@ static char **print_formatted(char *f, char **argv, int *conv_err)
case '%':
direc_start = f++;
direc_length = 1;
- field_width = precision = 0;
+ field_width = 0;
+ precision = 0;
if (*f == '%') {
- bb_putchar('%');
+ putchar_str(inf, '%');
break;
}
if (*f == 'b') {
if (*argv) {
- if (print_esc_string(*argv))
+ if (print_esc_string(inf, *argv))
return saved_argv; /* causes main() to exit */
++argv;
}
@@ -467,24 +540,28 @@ static char **print_formatted(char *f, char **argv, int *conv_err)
/* Remove "lLhz" size modifiers, repeatedly.
* bash does not like "%lld", but coreutils
* happily takes even "%Llllhhzhhzd"!
- * We are permissive like coreutils */
- while ((*f | 0x20) == 'l' || *f == 'h' || *f == 'z') {
+ * We are permissive like coreutils
+ */
+ while ((*f | 0x20) == 'l' || *f == 'h' || *f == 'z')
overlapping_strcpy(f, f + 1);
- }
/* Add "ll" if integer modifier, then print */
{
- static const char format_chars[] ALIGN1 = "diouxXfeEgGcs";
+ static const char format_chars[] = "diouxXcs";
char *p = strchr(format_chars, *f);
/* needed - try "printf %" without it */
- if (p == NULL || *f == '\0') {
- bb_error_msg("%s: invalid format", direc_start);
+ if (!p || *f == '\0') {
+ printf("`%s': invalid format\n", direc_start);
/* causes main() to exit with error */
return saved_argv - 1;
}
++direc_length;
if (p - format_chars <= 5) {
/* it is one of "diouxX" */
- p = xmalloc(direc_length + 3);
+ p = malloc(direc_length + 3);
+ if (!p) {
+ /* exit with error */
+ return saved_argv - 1;
+ }
memcpy(p, direc_start, direc_length);
p[direc_length + 1] = p[direc_length - 1];
p[direc_length - 1] = 'l';
@@ -496,81 +573,75 @@ static char **print_formatted(char *f, char **argv, int *conv_err)
p = NULL;
}
if (*argv) {
- print_direc(direc_start, direc_length, field_width,
- precision, *argv++);
+ print_direc(inf, direc_start, direc_length,
+ field_width, precision, *argv++);
} else {
- print_direc(direc_start, direc_length, field_width,
- precision, "");
+ print_direc(inf, direc_start, direc_length,
+ field_width, precision, "");
}
*conv_err |= errno;
free(p);
}
break;
case '\\':
- if (*++f == 'c') {
+ if (*++f == 'c')
return saved_argv; /* causes main() to exit */
- }
- bb_putchar(bb_process_escape_sequence((const char **)&f));
+ putchar_str(inf, process_escape_sequence((const char **)&f));
f--;
break;
default:
- putchar(*f);
+ putchar_str(inf, *f);
}
}
return argv;
}
-int printf_main(int argc UNUSED_PARAM, char **argv)
+/**
+ * printf_setexpr() - Implements the setexpr <name> fmt <format> command
+ *
+ * This function implements the format string evaluation for the
+ * setexpr <name> fmt <format> <value> command.
+ *
+ * @str: Output string of the evaluated expression
+ * @size: Length of @str buffer
+ * @argc: Number of arguments
+ * @argv: Argument list
+ * @return: 0 if OK, 1 on error
+ */
+int printf_setexpr(char *str, size_t size, int argc, char *const *argv)
{
int conv_err;
char *format;
char **argv2;
+ struct print_inf inf = {
+ .str = str,
+ .size = size,
+ .offset = 0,
+ .error = 0,
+ };
+
+ if (!str || !size)
+ return 1;
- /* We must check that stdout is not closed.
- * The reason for this is highly non-obvious.
- * printf_main is used from shell.
- * Shell must correctly handle 'printf "%s" foo'
- * if stdout is closed. With stdio, output gets shoveled into
- * stdout buffer, and even fflush cannot clear it out. It seems that
- * even if libc receives EBADF on write attempts, it feels determined
- * to output data no matter what. So it will try later,
- * and possibly will clobber future output. Not good. */
-// TODO: check fcntl() & O_ACCMODE == O_WRONLY or O_RDWR?
- if (fcntl(1, F_GETFL) == -1)
- return 1; /* match coreutils 6.10 (sans error msg to stderr) */
- //if (dup2(1, 1) != 1) - old way
- // return 1;
-
- /* bash builtin errors out on "printf '-%s-\n' foo",
- * coreutils-6.9 works. Both work with "printf -- '-%s-\n' foo".
- * We will mimic coreutils. */
- if (argv[1] && argv[1][0] == '-' && argv[1][1] == '-' && !argv[1][2])
- argv++;
- if (!argv[1]) {
- if (ENABLE_ASH_PRINTF
- && applet_name[0] != 'p'
- ) {
- bb_simple_error_msg("usage: printf FORMAT [ARGUMENT...]");
- return 2; /* bash compat */
- }
- bb_show_usage();
- }
+ inf.str[0] = '\0';
- format = argv[1];
- argv2 = argv + 2;
+ format = argv[0];
+ argv2 = (char **)argv + 1;
conv_err = 0;
- do {
- argv = argv2;
- argv2 = print_formatted(format, argv, &conv_err);
- } while (argv2 > argv && *argv2);
+ argv = argv2;
+ /* In case any print_str call raises an error inf.error will be
+ * set after print_formatted returns.
+ */
+ argv2 = print_formatted(&inf, format, (char **)argv, &conv_err);
/* coreutils compat (bash doesn't do this):
- if (*argv)
- fprintf(stderr, "excess args ignored");
- */
+ *if (*argv)
+ * fprintf(stderr, "excess args ignored");
+ */
- return (argv2 < argv) /* if true, print_formatted errored out */
- || conv_err; /* print_formatted saw invalid number */
+ return (argv2 < argv) || /* if true, print_formatted errored out */
+ conv_err || /* print_formatted saw invalid number */
+ inf.error; /* print_str reported error */
}
diff --git a/cmd/printf.h b/cmd/printf.h
new file mode 100644
index 0000000000..dcaff6d097
--- /dev/null
+++ b/cmd/printf.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+
+#ifndef __PRINTF_H
+#define __PRINTF_H
+
+int printf_setexpr(char *str, size_t size, int argc, char *const *argv);
+
+#endif
diff --git a/cmd/setexpr.c b/cmd/setexpr.c
index e828be3970..1eb67e2eff 100644
--- a/cmd/setexpr.c
+++ b/cmd/setexpr.c
@@ -11,11 +11,15 @@
#include <common.h>
#include <config.h>
#include <command.h>
+#include <ctype.h>
#include <env.h>
#include <log.h>
#include <malloc.h>
#include <mapmem.h>
#include <linux/sizes.h>
+#include "printf.h"
+
+#define MAX_STR_LEN 128
/**
* struct expr_arg: Holds an argument to an expression
@@ -370,15 +374,16 @@ static int do_setexpr(struct cmd_tbl *cmdtp, int flag, int argc,
int w;
/*
- * We take 3, 5, or 6 arguments:
+ * We take 3, 5, or 6 arguments, except fmt operation, which
+ * takes 4 to 8 arguments (limited by _maxargs):
* 3 : setexpr name value
* 5 : setexpr name val1 op val2
* setexpr name [g]sub r s
* 6 : setexpr name [g]sub r s t
+ * setexpr name fmt format [val1] [val2] [val3] [val4]
*/
- /* > 6 already tested by max command args */
- if ((argc < 3) || (argc == 4))
+ if (argc < 3)
return CMD_RET_USAGE;
w = cmd_get_data_size(argv[0], 4);
@@ -386,6 +391,24 @@ static int do_setexpr(struct cmd_tbl *cmdtp, int flag, int argc,
if (get_arg(argv[2], w, &aval))
return CMD_RET_FAILURE;
+ /* format string assignment: "setexpr name fmt %d value" */
+ if (strcmp(argv[2], "fmt") == 0 && IS_ENABLED(CONFIG_CMD_SETEXPR_FMT)) {
+ char str[MAX_STR_LEN];
+ int result;
+
+ if (argc == 3)
+ return CMD_RET_USAGE;
+
+ result = printf_setexpr(str, sizeof(str), argc - 3, &argv[3]);
+ if (result)
+ return result;
+
+ return env_set(argv[1], str);
+ }
+
+ if (argc == 4 || argc > 6)
+ return CMD_RET_USAGE;
+
/* plain assignment: "setexpr name value" */
if (argc == 3) {
if (w == CMD_DATA_SIZE_STR) {
@@ -495,7 +518,7 @@ static int do_setexpr(struct cmd_tbl *cmdtp, int flag, int argc,
}
U_BOOT_CMD(
- setexpr, 6, 0, do_setexpr,
+ setexpr, 8, 0, do_setexpr,
"set environment variable as the result of eval expression",
"[.b, .w, .l, .s] name [*]value1 <op> [*]value2\n"
" - set environment variable 'name' to the result of the evaluated\n"
@@ -505,6 +528,12 @@ U_BOOT_CMD(
" memory addresses (*)\n"
"setexpr[.b, .w, .l] name [*]value\n"
" - load a value into a variable"
+#ifdef CONFIG_CMD_SETEXPR_FMT
+ "\n"
+ "setexpr name fmt <format> [value1] [value2] [value3] [value4]\n"
+ " - set environment variable 'name' to the result of the bash like\n"
+ " format string evaluation of value."
+#endif
#ifdef CONFIG_REGEX
"\n"
"setexpr name gsub r s [t]\n"
--
2.25.1
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