[U-Boot] [PATCH 3/4] Add pxecfg command

Jason Hobbs jason.hobbs at calxeda.com
Mon Jun 6 20:56:38 CEST 2011


Add pxecfg command, which is intended to mimic PXELINUX functionality.
'pxecfg get' uses tftp to retrieve a file based on UUID, MAC address or
IP address. 'pxecfg boot' interprets the contents of PXELINUX config
like file to boot using a specific initrd, kernel and kernel command
line.

This patch also adds a README.pxecfg file - see it for more details on
the pxecfg command.

Signed-off-by: Jason Hobbs <jason.hobbs at calxeda.com>
---
 common/Makefile     |    1 +
 common/cmd_pxecfg.c | 1070 +++++++++++++++++++++++++++++++++++++++++++++++++++
 doc/README.pxecfg   |  238 ++++++++++++
 include/common.h    |    5 +
 4 files changed, 1314 insertions(+), 0 deletions(-)
 create mode 100644 common/cmd_pxecfg.c
 create mode 100644 doc/README.pxecfg

diff --git a/common/Makefile b/common/Makefile
index f81cff9..7e5e16e 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -136,6 +136,7 @@ COBJS-$(CONFIG_CMD_PCI) += cmd_pci.o
 endif
 COBJS-y += cmd_pcmcia.o
 COBJS-$(CONFIG_CMD_PORTIO) += cmd_portio.o
+COBJS-$(CONFIG_CMD_PXECFG) += cmd_pxecfg.o
 COBJS-$(CONFIG_CMD_REGINFO) += cmd_reginfo.o
 COBJS-$(CONFIG_CMD_REISER) += cmd_reiser.o
 COBJS-$(CONFIG_CMD_SATA) += cmd_sata.o
diff --git a/common/cmd_pxecfg.c b/common/cmd_pxecfg.c
new file mode 100644
index 0000000..d761ceb
--- /dev/null
+++ b/common/cmd_pxecfg.c
@@ -0,0 +1,1070 @@
+/*
+ * Copyright 2010-2011 Calxeda, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <common.h>
+#include <command.h>
+#include <malloc.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <errno.h>
+
+#define MAX_TFTP_PATH_LEN 127
+
+/*
+ * Returns the ethaddr environment variable formated with -'s instead of :'s
+ */
+static void format_mac_pxecfg(char **outbuf)
+{
+	char *p, *ethaddr;
+
+	*outbuf = NULL;
+
+	ethaddr = getenv("ethaddr");
+
+	if (!ethaddr)
+		return;
+
+	*outbuf = strdup(ethaddr);
+
+	if (*outbuf == NULL)
+		return;
+
+	for (p = *outbuf; *p; p++)
+		if (*p == ':')
+			*p = '-';
+}
+
+/*
+ * Returns the directory the file specified in the bootfile env variable is
+ * in.
+ */
+static char *get_bootfile_path(void)
+{
+	char *bootfile, *bootfile_path, *last_slash;
+
+	bootfile = getenv("bootfile");
+
+	if (bootfile == NULL) {
+		printf("Missing bootfile environment variable.\n");
+		return NULL;
+	}
+
+	bootfile_path = strdup(bootfile);
+
+	if (bootfile_path == NULL) {
+		printf("oom\n");
+		return NULL;
+	}
+
+	last_slash = strrchr(bootfile_path, '/');
+
+	if (last_slash == NULL) {
+		printf("Invalid bootfile path (%s), no '/' found\n",
+				bootfile_path);
+
+		return NULL;
+	}
+
+	*last_slash = '\0';
+
+	return bootfile_path;
+}
+
+static int get_relfile(char *file_path, void *file_addr)
+{
+	char *bootfile_path;
+	size_t path_len;
+	char bootfile[MAX_TFTP_PATH_LEN+1];
+	char addr_buf[10];
+	char *tftp_argv[] = {"tftp", NULL, NULL, NULL};
+
+	bootfile_path = get_bootfile_path();
+
+	if (bootfile_path == NULL) {
+		printf("No bootfile path in environment.\n");
+		return -ENOENT;
+	}
+
+	path_len = strlen(bootfile_path) + strlen(file_path) + 1;
+
+	if (path_len > MAX_TFTP_PATH_LEN) {
+		printf("Base path too long (%s/%s)\n",
+				bootfile_path, file_path);
+
+		free(bootfile_path);
+		return -ENAMETOOLONG;
+	}
+
+	sprintf(bootfile, "%s/%s", bootfile_path, file_path);
+
+	free(bootfile_path);
+
+	printf("Retreiving file: %s\n", bootfile);
+
+	sprintf(addr_buf, "%p", file_addr);
+
+	tftp_argv[1] = addr_buf;
+	tftp_argv[2] = bootfile;
+
+	if (do_tftpb(NULL, 0, 3, tftp_argv)) {
+		printf("File not found\n");
+		return -ENOENT;
+	}
+
+	return 1;
+}
+
+static int get_pxecfg_file(char *file_path, void *file_addr)
+{
+	unsigned long config_file_size;
+	int err;
+
+	err = get_relfile(file_path, file_addr);
+
+	if (err < 0)
+		return err;
+
+	config_file_size = simple_strtoul(getenv("filesize"), NULL, 16);
+	*(char *)(file_addr + config_file_size) = '\0';
+
+	return 1;
+}
+
+
+#define MAX_CFG_PATHS	12
+
+/*
+ * Returns a list of paths according to the pxelinux rules for paths to a
+ * config file.  The base of each path is the same -
+ * bootfilepath/pxelinux.cfg/uniquepart. bootfilepath is the directory
+ * bootfile (from the dhcp request) was in, joined with '/pxelinux.cfg'.  The
+ * unique part of each file comes from these things, in this order:
+ *
+ * pxeuuid env variable verbatim, if defined
+ * ethaddr env variable, reformatted with -'s instead of :'s
+ * hexadecimal formatted IP address
+ * hexadecimal IP address with last hex digit removed
+ * repeat removing another character until none are left
+ * the string 'default'
+ *
+ * see http://syslinux.zytor.com/wiki/index.php/PXELINUX
+ */
+static char **pxecfg_paths(char *uuid_str, char *mac_addr)
+{
+	char **ret_array;
+	char ip_addr[9];
+	int x, end_masks, mask_pos;
+	size_t base_len = strlen("pxelinux.cfg/");
+
+	sprintf(ip_addr, "%08X", ntohl(NetOurIP));
+
+	ret_array = malloc(MAX_CFG_PATHS * sizeof(char *));
+
+	if (ret_array == NULL) {
+		printf("oom\n");
+		return NULL;
+	}
+
+	for (x = 0; x < MAX_CFG_PATHS; x++)
+		ret_array[x] = NULL;
+
+	x = 0;
+
+	if (uuid_str) {
+		if (base_len + strlen(uuid_str) > MAX_TFTP_PATH_LEN)
+			printf("uuid_str is too long, skipping\n");
+		else  {
+			ret_array[x] = malloc(MAX_TFTP_PATH_LEN + 1);
+			if (!ret_array[x])
+				goto oom_error;
+
+			sprintf(ret_array[x++], "pxelinux.cfg/%s", uuid_str);
+		}
+	}
+
+	if (mac_addr) {
+		if (base_len + strlen(mac_addr) > MAX_TFTP_PATH_LEN)
+			printf("ethaddr is too long, skipping\n");
+		else {
+			ret_array[x] = malloc(MAX_TFTP_PATH_LEN + 1);
+			if (!ret_array[x])
+				goto oom_error;
+
+			sprintf(ret_array[x++], "pxelinux.cfg/%s", mac_addr);
+		}
+	}
+
+	for (end_masks = x + 8, mask_pos = 7; x < end_masks; x++, mask_pos--) {
+		ret_array[x] = malloc(MAX_TFTP_PATH_LEN + 1);
+		if (!ret_array[x])
+			goto oom_error;
+
+		sprintf(ret_array[x], "pxelinux.cfg/%s", ip_addr);
+
+		ip_addr[mask_pos] = '\0';
+	}
+
+	ret_array[x] = malloc(MAX_TFTP_PATH_LEN + 1);
+	if (!ret_array[x])
+		goto oom_error;
+
+	strcpy(ret_array[x++], "pxelinux.cfg/default");
+
+	return ret_array;
+
+oom_error:
+	printf("oom\n");
+
+	if (ret_array) {
+		while (ret_array[x])
+			free(ret_array[x++]);
+
+		free(ret_array);
+	}
+
+	return NULL;
+}
+
+/*
+ * Follows pxelinux's rules to download a pxecfg file from a tftp server.  The
+ * file is stored at the location given by the pxecfg_addr environment
+ * variable, which must be set.
+ */
+static int get_pxecfg(int argc, char * const argv[])
+{
+	char *mac_addr, *pxecfg_ram, **cfg_paths = NULL;
+	int i, cfg_file_found = 0, err;
+	void *pxecfg_addr;
+
+	pxecfg_ram = getenv("pxecfg_ram");
+
+	if (!pxecfg_ram) {
+		printf("Missing pxecfg_ram\n");
+		return 1;
+	}
+
+	pxecfg_addr = (void *)simple_strtoul(pxecfg_ram, NULL, 16);
+
+	format_mac_pxecfg(&mac_addr);
+
+	cfg_paths = pxecfg_paths(getenv("pxeuuid"), mac_addr);
+
+	if (cfg_paths == NULL)
+		return 1;
+
+	for (i = 0; cfg_paths[i]; i++) {
+		err = get_pxecfg_file(cfg_paths[i], pxecfg_addr);
+		if (err > 0) {
+			cfg_file_found = 1;
+			break;
+		}
+	}
+
+	for (i = 0; cfg_paths[i]; i++)
+		free(cfg_paths[i]);
+
+	if (!cfg_file_found)
+		return 1;
+
+	printf("Config file found!\n");
+
+	return 0;
+}
+
+struct pxecfg_menu_item {
+	char *name;
+	char *kernel;
+	char *append;
+	char *initrd;
+	int attempted;
+	int localboot;
+	struct pxecfg_menu_item *next;
+};
+
+struct pxecfg_menu {
+	char *default_label;
+	int timeout;
+	char *title;
+	int prompt;
+	struct pxecfg_menu_item *labels;
+};
+
+static void add_label(struct pxecfg_menu *menu, struct pxecfg_menu_item *item)
+{
+	struct pxecfg_menu_item *iter;
+
+	if (menu->labels == NULL) {
+		menu->labels = item;
+	} else {
+		iter = menu->labels;
+
+		while (iter->next != NULL)
+			iter = iter->next;
+
+		iter->next = item;
+	}
+
+	item->kernel = NULL;
+	item->append = NULL;
+	item->initrd = NULL;
+	item->next = NULL;
+	item->localboot = 0;
+	item->attempted = 0;
+}
+
+struct pxecfg_menu_item *label_by_name(struct pxecfg_menu_item *head,
+					char *name)
+{
+	struct pxecfg_menu_item *iter_label = head;
+
+	while (iter_label)
+		if (!strcmp(name, iter_label->name))
+			return iter_label;
+		else
+			iter_label = iter_label->next;
+
+	return NULL;
+}
+
+enum token_type {
+	T_EOL,
+	T_STRING,
+	T_EOF,
+	T_MENU,
+	T_TITLE,
+	T_TIMEOUT,
+	T_LABEL,
+	T_KERNEL,
+	T_APPEND,
+	T_INITRD,
+	T_LOCALBOOT,
+	T_DEFAULT,
+	T_PROMPT,
+	T_INCLUDE,
+	T_INVALID
+};
+
+struct token {
+	char *val;
+	enum token_type type;
+};
+
+enum lex_state {
+	L_NORMAL = 0,
+	L_KEYWORD,
+	L_SLITERAL
+};
+
+static const struct token keywords[] = {
+	{"menu", T_MENU},
+	{"title", T_TITLE},
+	{"timeout", T_TIMEOUT},
+	{"default", T_DEFAULT},
+	{"prompt", T_PROMPT},
+	{"label", T_LABEL},
+	{"kernel", T_KERNEL},
+	{"localboot", T_LOCALBOOT},
+	{"append", T_APPEND},
+	{"initrd", T_INITRD},
+	{"include", T_INCLUDE},
+	{NULL, T_INVALID}
+};
+
+static char *get_string(char **p, struct token *t, char delim, int lower)
+{
+	char *b, *e;
+	size_t len, i;
+
+	b = e = *p;
+
+	while (*e) {
+		if ((delim == ' ' && isspace(*e)) || delim == *e)
+			break;
+		e++;
+	}
+
+	len = e - b;
+
+	t->val = malloc(len + 1);
+	if (!t->val) {
+		printf("oom\n");
+		return NULL;
+	}
+
+	for (i = 0; i < len; i++, b++) {
+		if (lower)
+			t->val[i] = tolower(*b);
+		else
+			t->val[i] = *b;
+	}
+
+	t->val[len] = '\0';
+
+	*p = e;
+
+	t->type = T_STRING;
+
+	return t->val;
+}
+
+static void get_keyword(struct token *t)
+{
+	int i;
+
+	for (i = 0; keywords[i].val; i++) {
+		if (!strcmp(t->val, keywords[i].val)) {
+			t->type = keywords[i].type;
+			break;
+		}
+	}
+}
+
+static void get_token(char **p, struct token *t, enum lex_state state)
+{
+	char *c = *p;
+
+	t->type = T_INVALID;
+
+	/* eat non EOL whitespace */
+	while (*c == ' ' || *c == '\t')
+		c++;
+
+	/* eat comments */
+	if (*c == '#')
+		while (*c && *c != '\n')
+			c++;
+
+	if (*c == '\n') {
+		t->type = T_EOL;
+		c++;
+	} else if (*c == '\0') {
+		t->type = T_EOF;
+		c++;
+	} else if (state == L_SLITERAL)
+		get_string(&c, t, '\n', 0);
+	else if (state == L_KEYWORD) {
+		get_string(&c, t, ' ', 1);
+		get_keyword(t);
+	}
+
+	*p = c;
+}
+
+static void eol_or_eof(char **c)
+{
+	while (**c && **c != '\n')
+		(*c)++;
+}
+
+static int parse_sliteral(char **c, char **dst)
+{
+	struct token t;
+	char *s = *c;
+
+	get_token(c, &t, L_SLITERAL);
+
+	if (t.type != T_STRING) {
+		printf("Expected string literal: %.*s\n", (int)(*c - s), s);
+		return -EINVAL;
+	}
+
+	*dst = t.val;
+
+	return 1;
+}
+
+static int parse_integer(char **c, int *dst)
+{
+	struct token t;
+	char *s = *c;
+
+	get_token(c, &t, L_SLITERAL);
+
+	if (t.type != T_STRING) {
+		printf("Expected string: %.*s\n", (int)(*c - s), s);
+		return -EINVAL;
+	}
+
+	*dst = (int)simple_strtoul(t.val, NULL, 10);
+
+	free(t.val);
+
+	return 1;
+}
+
+static int parse_pxecfg_top(char *p, struct pxecfg_menu *m, int nest_level);
+
+static int handle_include(char **c, char *base, struct pxecfg_menu *m,
+						int nest_level)
+{
+	char *include_path;
+	int err;
+
+	err = parse_sliteral(c, &include_path);
+
+	if (err < 0) {
+		printf("Expected include path\n");
+		return err;
+	}
+
+	err = get_pxecfg_file(include_path, base);
+
+	if (err < 0) {
+		printf("Couldn't get %s\n", include_path);
+		return err;
+	}
+
+	return parse_pxecfg_top(base, m, nest_level);
+}
+
+static int parse_menu(char **c, struct pxecfg_menu *m, char *b, int nest_level)
+{
+	struct token t;
+	char *s = *c;
+	int err;
+
+	get_token(c, &t, L_KEYWORD);
+
+	switch (t.type) {
+	case T_TITLE:
+		err = parse_sliteral(c, &m->title);
+		break;
+
+	case T_INCLUDE:
+		err = handle_include(c, b + strlen(b) + 1, m,
+						nest_level + 1);
+		break;
+
+	default:
+		printf("Ignoring malformed menu command: %.*s\n",
+				(int)(*c - s), s);
+	}
+
+	if (err < 0)
+		return err;
+
+	eol_or_eof(c);
+
+	return 1;
+}
+
+static int parse_label_menu(char **c, struct pxecfg_menu *m,
+				struct pxecfg_menu_item *i)
+{
+	struct token t;
+	char *s;
+
+	s = *c;
+
+	get_token(c, &t, L_KEYWORD);
+
+	switch (t.type) {
+	case T_DEFAULT:
+		if (m->default_label != NULL)
+			free(m->default_label);
+
+		m->default_label = i->name;
+		break;
+	default:
+		printf("Ignoring malformed menu command: %.*s\n",
+				(int)(*c - s), s);
+	}
+
+	eol_or_eof(c);
+
+	return 0;
+}
+
+static int parse_label(char **c, struct pxecfg_menu *m)
+{
+	struct token t;
+	char *s;
+	struct pxecfg_menu_item *i;
+	int err;
+
+	i = malloc(sizeof(*i));
+
+	if (!i)
+		return -ENOMEM;
+
+	err = parse_sliteral(c, &i->name);
+
+	if (err < 0) {
+		printf("Expected label name\n");
+		return -EINVAL;
+	}
+
+	add_label(m, i);
+
+	while (1) {
+		s = *c;
+		get_token(c, &t, L_KEYWORD);
+
+		err = 0;
+		switch (t.type) {
+		case T_MENU:
+			err = parse_label_menu(c, m, i);
+			break;
+
+		case T_KERNEL:
+			err = parse_sliteral(c, &i->kernel);
+			break;
+
+		case T_APPEND:
+			err = parse_sliteral(c, &i->append);
+			break;
+
+		case T_INITRD:
+			err = parse_sliteral(c, &i->initrd);
+			break;
+
+		case T_LOCALBOOT:
+			err = parse_integer(c, &i->localboot);
+			break;
+
+		case T_EOL:
+			break;
+
+		/*
+		 * A label ends when we either get to the end of a file, or
+		 * get some input we otherwise don't have a handler defined
+		 * for.
+		 */
+		default:
+			/* put it back */
+			*c = s;
+			return 1;
+		}
+
+		if (err < 0)
+			return err;
+	}
+}
+
+#define MAX_NEST_LEVEL 16
+
+static int parse_pxecfg_top(char *p, struct pxecfg_menu *m, int nest_level)
+{
+	struct token t;
+	char *s, *b;
+	int err;
+
+	b = p;
+
+	if (nest_level > MAX_NEST_LEVEL) {
+		printf("Maximum nesting exceeded\n");
+		return -EMLINK;
+	}
+
+	while (1) {
+		s = p;
+
+		get_token(&p, &t, L_KEYWORD);
+
+		err = 0;
+		switch (t.type) {
+		case T_MENU:
+			err = parse_menu(&p, m, b, nest_level);
+			break;
+
+		case T_TIMEOUT:
+			err = parse_integer(&p, &m->timeout);
+			break;
+
+		case T_LABEL:
+			err = parse_label(&p, m);
+			break;
+
+		case T_DEFAULT:
+			err = parse_sliteral(&p, &m->default_label);
+			break;
+
+		case T_PROMPT:
+			err = parse_integer(&p, &m->prompt);
+			break;
+
+		case T_EOL:
+			break;
+
+		case T_EOF:
+			return 1;
+
+		default:
+			printf("Ignoring unknown command: %.*s\n",
+							(int)(p - s), s);
+			eol_or_eof(&p);
+		}
+
+		if (err < 0)
+			return err;
+	}
+}
+
+static struct pxecfg_menu *parse_pxecfg(char *menucfg)
+{
+	struct pxecfg_menu *menu;
+
+	menu = malloc(sizeof(*menu));
+
+	if (menu == NULL) {
+		printf("oom\n");
+		return NULL;
+	}
+
+	menu->timeout = -1;
+	menu->prompt = 0;
+	menu->default_label = NULL;
+	menu->title = NULL;
+	menu->labels = NULL;
+
+	if (parse_pxecfg_top(menucfg, menu, 1) < 0) {
+		free(menu);
+		return NULL;
+	}
+
+	return menu;
+}
+
+static int perform_localboot(struct pxecfg_menu_item *label)
+{
+	char *localcmd, *dupcmd;
+	int ret;
+
+	localcmd = getenv("localcmd");
+
+	if (!localcmd) {
+		printf("localcmd not defined\n");
+		return -ENOENT;
+	}
+
+	/*
+	 * We must dup the environment variable value here, because getenv
+	 * returns a pointer directly into the environment, and the contents
+	 * of the environment might shift during execution of a command.
+	 */
+	dupcmd = strdup(localcmd);
+
+	if (!dupcmd) {
+		printf("oom\n");
+		return -ENOMEM;
+	}
+
+	if (label->append)
+		setenv("bootargs", label->append);
+
+	printf("running: %s\n", dupcmd);
+
+	ret = run_command2(dupcmd, 0);
+
+	free(dupcmd);
+
+	return ret;
+}
+
+static int get_relfile_envaddr(char *file_path, char *envaddr_name)
+{
+	void *file_addr;
+	char *envaddr;
+
+	envaddr = getenv(envaddr_name);
+
+	if (!envaddr) {
+		printf("missing: %s\n", envaddr_name);
+		return -ENOENT;
+	}
+
+	file_addr = (void *)simple_strtoul(envaddr, NULL, 16);
+
+	return get_relfile(file_path, file_addr);
+}
+
+static void print_label(struct pxecfg_menu_item *label)
+{
+	printf("Label: %s\n", label->name);
+
+	if (label->kernel)
+		printf("\tkernel: %s\n", label->kernel);
+
+	if (label->append)
+		printf("\tappend: %s\n", label->append);
+
+	if (label->initrd)
+		printf("\tinitrd: %s\n", label->initrd);
+}
+
+static void print_menu(struct pxecfg_menu *menu)
+{
+	struct pxecfg_menu_item *iter;
+
+	if (menu->title)
+		printf("Menu: %s\n", menu->title);
+
+	iter = menu->labels;
+
+	while (iter) {
+		print_label(iter);
+
+		iter = iter->next;
+	}
+}
+
+static void destroy_label(struct pxecfg_menu_item *label)
+{
+	if (label->name)
+		free(label->name);
+
+	if (label->kernel)
+		free(label->kernel);
+
+	if (label->append)
+		free(label->append);
+
+	if (label->initrd)
+		free(label->initrd);
+
+	free(label);
+}
+
+static void destroy_menu(struct pxecfg_menu *menu)
+{
+	struct pxecfg_menu_item *iter, *next;
+
+	if (!menu)
+		return;
+
+	iter = menu->labels;
+
+	while (iter) {
+		next = iter->next;
+		destroy_label(iter);
+		iter = next;
+	}
+
+	free(menu);
+}
+
+/*
+ * Do what it takes to boot a chosen label.
+ *
+ * Retreive the kernel and initrd, and prepare bootargs.
+ */
+static void boot_label(struct pxecfg_menu_item *label)
+{
+	char *bootm_argv[] = { "bootm", NULL, NULL, NULL, NULL };
+
+	print_label(label);
+
+	label->attempted = 1;
+
+	if (label->localboot) {
+		perform_localboot(label);
+		return;
+	}
+
+	if (label->kernel == NULL) {
+		printf("No kernel given, skipping label\n");
+		return;
+	}
+
+	if (label->initrd) {
+		if (get_relfile_envaddr(label->initrd, "initrd_ram") < 0) {
+			printf("Skipping label\n");
+			return;
+		}
+
+		bootm_argv[2] = getenv("initrd_ram");
+	} else
+		bootm_argv[2] = "-";
+
+	if (get_relfile_envaddr(label->kernel, "kernel_ram") < 0) {
+		printf("Skipping label\n");
+		return;
+	}
+
+	if (label->append)
+		setenv("bootargs", label->append);
+
+	bootm_argv[1] = getenv("kernel_ram");
+
+	/*
+	 * fdt usage is optional - if unset, this stays NULL.
+	 */
+	bootm_argv[3] = getenv("fdtaddr");
+
+	do_bootm(NULL, 0, 4, bootm_argv);
+}
+
+/*
+ * Change the default to the user's choice.
+ */
+static void user_choice(struct pxecfg_menu *menu)
+{
+	char cbuf[CONFIG_SYS_CBSIZE];
+	struct pxecfg_menu_item *choice_label = NULL;
+
+	while (!choice_label) {
+		int readret;
+
+		cbuf[0] = '\0';
+
+		print_menu(menu);
+
+		readret = readline_into_buffer("Enter label: ", cbuf);
+
+		if (readret >= 0) {
+			choice_label = label_by_name(menu->labels, cbuf);
+
+			if (!choice_label)
+				printf("%s not found\n", cbuf);
+			else
+				boot_label(choice_label);
+		} else {
+			printf("^C\n");
+			return;
+		}
+	}
+}
+
+/*
+ * Honor the timeout period from the cfg file or from the bootdelay
+ * environment variable.
+ *
+ * If interrupted, allow the user to interactively choose a menu to boot from.
+ */
+static int delay_for_input(int timeout)
+{
+	char *bootdelay;
+
+	bootdelay = getenv("bootdelay");
+
+	if (timeout == -1) {
+		if (bootdelay)
+			timeout = simple_strtol(bootdelay, NULL, 10);
+		else
+			timeout = 0;
+	}
+
+	if (timeout) {
+		printf("using the timeout: %d\n", timeout);
+
+		if (_abortboot(timeout/10)) {
+			printf("autoboot aborted!\n");
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+static void handle_pxecfg(struct pxecfg_menu *menu)
+{
+	struct pxecfg_menu_item *iter_label, *label = NULL;
+
+	if (menu->labels == NULL) {
+		printf("Configuration provided no labels, can't boot\n");
+		return;
+	}
+
+	if (menu->prompt || delay_for_input(menu->timeout)) {
+		user_choice(menu);
+		return;
+	}
+
+	if (menu->default_label) {
+		printf("Attempting to boot from default label: %s\n",
+				menu->default_label);
+
+		label = label_by_name(menu->labels, menu->default_label);
+
+		if (label == NULL)
+			label = menu->labels;
+	} else
+		label = menu->labels;
+
+	while (label) {
+		boot_label(label);
+
+		label = NULL;
+
+		iter_label = menu->labels;
+
+		while (!label && iter_label) {
+			if (!iter_label->attempted)
+				label = iter_label;
+
+			iter_label = iter_label->next;
+		}
+	}
+}
+
+static int boot_pxecfg(int argc, char * const argv[])
+{
+	unsigned long pxecfg_addr;
+	struct pxecfg_menu *menu;
+	char *pxecfg_ram;
+
+	if (argc == 2) {
+		pxecfg_ram = getenv("pxecfg_ram");
+		if (pxecfg_ram == NULL) {
+			printf("Missing pxecfg_ram in environment\n");
+			return 1;
+		}
+
+		pxecfg_addr = simple_strtoul(pxecfg_ram, NULL, 16);
+	} else if (argc == 3) {
+		pxecfg_addr = simple_strtoul(argv[2], NULL, 16);
+	} else {
+		printf("Invalid number of arguments\n");
+		return 1;
+	}
+
+	menu = parse_pxecfg((char *)(pxecfg_addr));
+
+	if (menu == NULL) {
+		printf("Error parsing config file\n");
+		return 1;
+	}
+
+	handle_pxecfg(menu);
+
+	destroy_menu(menu);
+
+	return 0;
+}
+
+int do_pxecfg(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	if (argc < 2) {
+		printf("pxecfg requires at least one argument\n");
+		return EINVAL;
+	}
+
+	if (!strcmp(argv[1], "get"))
+		return get_pxecfg(argc, argv);
+
+	if (!strcmp(argv[1], "boot"))
+		return boot_pxecfg(argc, argv);
+
+	printf("Invalid pxecfg command: %s\n", argv[1]);
+
+	return EINVAL;
+}
+
+U_BOOT_CMD(
+	pxecfg, 2, 1, do_pxecfg,
+	"commands to get and boot from pxecfg files",
+	"get - try to retrieve a pxecfg file using tftp\npxecfg "
+	"boot [pxecfg_addr] - boot from the pxecfg file at pxecfg_addr\n"
+);
diff --git a/doc/README.pxecfg b/doc/README.pxecfg
new file mode 100644
index 0000000..57abef8
--- /dev/null
+++ b/doc/README.pxecfg
@@ -0,0 +1,238 @@
+/*
+ * Copyright 2010-2011 Calxeda, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+The pxecfg commands provide a near subset of the functionality provided by
+the PXELINUX boot loader. This allows U-boot based systems to be controlled
+remotely using the same PXE based techniques that many non U-boot based servers
+use. To avoid identity confusion with PXELINUX, and because not all behavior is
+identical, we call this feature 'pxecfg'.
+
+Commands
+========
+
+pxecfg get
+----------
+     syntax: pxecfg get
+
+     follows PXELINUX's rules for retrieving configuration files from a tftp
+     server, and supports a subset of PXELINUX's config file syntax.
+
+     Environment
+     -----------
+     get_pxecfg requires two environment variables to be set:
+
+     pxecfg_ram - should be set to a location in RAM large enough to hold
+     pxecfg files while they're being processed. Up to 16 config files may be
+     held in memory at once. The exact number and size of the files varies with
+     how the system is being used. A typical config file is a few hundred bytes
+     long.
+
+     bootfile,serverip - these two are typically set in the DHCP response
+     handler, and correspond to fields in the DHCP response.
+
+     get_pxecfg optionally supports these two environment variables being set:
+
+     ethaddr - this is the standard MAC address for the ethernet adapter in use.
+     getpxe_cfg uses it to look for a configuration file specific to a system's
+     MAC address.
+
+     pxeuuid - this is a UUID in standard form using lower case hexadecimal
+     digits, for example, 550e8400-e29b-41d4-a716-446655440000. get_pxecfg uses
+     it to look for a configuration file based on the system's UUID.
+
+     File Paths
+     ----------
+     get_pxecfg repeatedly tries to download config files until it either
+     successfully downloads one or runs out of paths to try. The order and
+     contents of paths it tries mirrors exactly that of PXELINUX - you can read
+     in more detail about it at:
+
+     http://syslinux.zytor.com/wiki/index.php/Doc/pxelinux
+
+pxecfg boot
+-----------
+     syntax: pxecfg boot [pxecfg_addr]
+
+     Interprets a pxecfg file stored in memory.
+
+     pxecfg_addr is an optional argument giving the location of the pxecfg file
+
+     Environment
+     -----------
+     There are some environment variables that may need to be set, depending on
+     conditions.
+
+     pxecfg_ram - if the optional argument pxecfg_addr is not supplied, an
+     environment variable named pxecfg_ram must be supplied. This is typically
+     the same value as is used for the get_pxecfg command.
+
+     bootfile - typically set in the DHCP response handler based on the same
+     field in the DHCP respone, this path is used to generate the base directory
+     that all other paths to files retrieved by boot_pxecfg will use.
+
+     serverip - typically set in the DHCP response handler, this is the IP
+     address of the tftp server from which other files will be retrieved.
+
+     kernel_ram,initrd_ram - locations in RAM at which boot_pxecfg will store
+     the kernel and initrd it retrieves from tftp. These locations will be
+     passed to the bootm command to boot the kernel. These environment variables
+     are required to be set.
+
+     fdtaddr - the location of a fdt blob. If this is set, it will be passed to
+     bootm when booting a kernel.
+
+pxecfg file format
+==================
+The pxecfg file format is more or less a subset of the PXELINUX file format, see
+http://syslinux.zytor.com/wiki/index.php/PXELINUX. It's composed of one line
+commands - global commands, and commands specific to labels. Lines begining with
+# are treated as comments. White space between and at the beginning of lines is
+ignored.
+
+The size of pxecfg files and the number of labels is only limited by the amount
+of RAM available to U-boot. Memory for labels is dynamically allocated as
+they're parsed, and memory for pxecfg files is statically allocated, and its
+location is given by the pxecfg_ram environment variable. the pxecfg code is
+not aware of the size of the pxecfg memory and will outgrow it if pxecfg files
+are too large.
+
+Supported global commands
+-------------------------
+Unrecognized commands are ignored.
+
+default <label>     - the label named here is treated as the default and is
+                      the first label boot_pxecfg attempts to boot.
+
+menu title <string> - sets a title for the menu of labels being displayed.
+
+menu include <path> - use tftp to retrieve the pxecfg file at <path>, which
+                      is then immediately parsed as if the start of its
+                      contents were the next line in the current file. nesting
+                      of include up to 16 files deep is supported.
+
+prompt <flag>       - if 1, always prompt the user to enter a label to boot
+                      from. if 0, only prompt the user if timeout expires.
+
+timeout <num>	    - wait for user input for <num>/10 seconds before
+                      auto-booting a node.
+
+label <name>        - begin a label definition. labels continue until
+                      a command not recognized as a label command is seen,
+                      or EOF is reached.
+
+Supported label commands
+------------------------
+labels end when a command not recognized as a label command is reached, or EOF.
+
+menu default        - set this label as the default label to boot; this is
+                      the same behavior as the global default command but
+                      specified in a different way
+
+kernel <path>       - if this label is chosen, use tftp to retrieve the kernel
+                      at <path>. it will be stored at the address indicated in
+                      the kernel_ram environment variable, and that address
+                      will be passed to bootm to boot this kernel.
+
+append <string>     - use <string> as the kernel command line when booting this
+                      label.
+
+initrd <path>       - if this label is chosen, use tftp to retrieve the initrd
+                      at <path>. it will be stored at the address indicated in
+                      the initrd_ram environment variable, and that address
+                      will be passed to bootm.
+
+localboot <flag>    - Run the command defined by "localcmd" in the environment.
+                      <flag> is ignored and is only here to match the syntax of
+                      PXELINUX config files.
+
+Example
+-------
+Here's a couple of example files to show how this works.
+
+------------/tftpboot/pxelinux.cfg/menus/linux.list----------
+menu title Linux selections
+
+# This is the default label
+label install
+	menu label Default Install Image
+	kernel kernels/install.bin
+	append console=ttyAMA0,38400 debug earlyprintk
+	initrd initrds/uzInitrdDebInstall
+
+# Just another label
+label linux-2.6.38
+	kernel kernels/linux-2.6.38.bin
+	append root=/dev/sdb1
+
+# The locally installed kernel
+label local
+	menu label Locally installed kernel
+	append root=/dev/sdb1
+	localboot 1
+-------------------------------------------------------------
+
+------------/tftpboot/pxelinux.cfg/default-------------------
+menu include pxelinux.cfg/menus/base.menu
+timeout 500
+
+default linux-2.6.38
+-------------------------------------------------------------
+
+When a pxecfg client retrieves and boots the default pxecfg file,
+boot_pxecfg will wait for user input for 5 seconds before booting
+the linux-2.6.38 label, which will cause /tftpboot/kernels/linux-2.6.38.bin
+to be downloaded, and boot with the command line "root=/dev/sdb1"
+
+Differences with PXELINUX
+=========================
+The biggest difference between pxecfg and PXELINUX is that since pxecfg
+is part of U-boot and is written entirely in C, it can run on platform
+with network support in U-boot.  Here are some of the other differences
+between PXELINUX and pxecfg.
+
+- pxecfg does not support the PXELINUX DHCP option codes specified in
+  RFC 5071, but could be extended to do so.
+
+- when pxecfg fails to boot, it will return control to U-boot, allowing
+  another command to run, other U-boot command, instead of resetting the
+  machine like PXELINUX.
+
+- pxecfg doesn't rely on or provide an UNDI/PXE stack in memory, it only
+  uses U-boot.
+
+- pxecfg doesn't provide the full menu implementation that PXELINUX
+  does, only a simple text based menu using the commands described in
+  this README.  With PXELINUX, it's possible to have a graphical boot
+  menu, submenus, passwords, etc. pxecfg could be extended to support
+  a more robust menuing system like that of PXELINUX's.
+
+- pxecfg expects U-boot uimg's as kernels.  anything that would work with
+  the 'bootm' command in U-boot could work with pxecfg.
+
+- pxecfg doesn't recognize initrd options in the append command - you must
+  specify initrd files using the initrd command
+
+- pxecfg only recognizes a single file on the initrd command line.  it
+  could be extended to support multiple
+
+- in pxecfg, the localboot command doesn't necessarily cause a local
+  disk boot - it will do whatever is defined in the 'localcmd' env
+  variable. And since it doesn't support a full UNDI/PXE stack, the
+  type field is ignored.
+
+- the interactive prompt in pxecfg only allows you to choose a label from
+  the menu.  if you want to boot something not listed, you can ctrl+c out
+  of pxecfg and use existing U-boot commands to accomplish it.
diff --git a/include/common.h b/include/common.h
index fd389e7..597e757 100644
--- a/include/common.h
+++ b/include/common.h
@@ -257,6 +257,11 @@ extern ulong load_addr;		/* Default Load Address */
 /* common/cmd_doc.c */
 void	doc_probe(unsigned long physadr);
 
+/* common/cmd_net.c */
+#ifdef CONFIG_CMD_NET
+int do_tftpb(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
+#endif
+
 /* common/cmd_nvedit.c */
 int	env_init     (void);
 void	env_relocate (void);
-- 
1.7.0.4



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