cmd_pxe.c

	struct token t;
	int len;
	char *s = *c;
	struct pxe_label *label;
	int err;

	label = label_create();
	if (!label)
		return -ENOMEM;

	err = parse_sliteral(c, &label->name);
	if (err < 0) {
		printf("Expected label name: %.*s\n", (int)(*c - s), s);
		label_destroy(label);
		return -EINVAL;
	}

	list_add_tail(&label->list, &cfg->labels);

	while (1) {
		s = *c;
		get_token(c, &t, L_KEYWORD);

		err = 0;
		switch (t.type) {
		case T_MENU:
			err = parse_label_menu(c, cfg, label);
			break;

		case T_KERNEL:
		case T_LINUX:
			err = parse_sliteral(c, &label->kernel);
			break;

		case T_APPEND:
			err = parse_sliteral(c, &label->append);
			if (label->initrd)
				break;
			s = strstr(label->append, "initrd=");
			if (!s)
				break;
			s += 7;
			len = (int)(strchr(s, ' ') - s);
			label->initrd = malloc(len + 1);
			strncpy(label->initrd, s, len);
			label->initrd[len] = '\0';

			break;

		case T_INITRD:
			if (!label->initrd)
				err = parse_sliteral(c, &label->initrd);
			break;

		case T_LOCALBOOT:
			err = parse_integer(c, &label->localboot);
			break;

		case T_EOL:
			break;

		default:
			/*
			 * put the token back! we don't want it - it's the end
			 * of a label and whatever token this is, it's
			 * something for the menu level context to handle.
			 */
			*c = s;
			return 1;
		}

		if (err < 0)
			return err;
	}
}

/*
 * This 16 comes from the limit pxelinux imposes on nested includes.
 *
 * There is no reason at all we couldn't do more, but some limit helps prevent
 * infinite (until crash occurs) recursion if a file tries to include itself.
 */
#define MAX_NEST_LEVEL 16

/*
 * Entry point for parsing a menu file. nest_level indicates how many times
 * we've nested in includes.  It will be 1 for the top level menu file.
 *
 * Returns 1 on success, < 0 on error.
 */
static int parse_pxefile_top(char *p, struct pxe_menu *cfg, int nest_level)
{
	struct token t;
	char *s, *b, *label_name;
	int err;

	b = p;

	if (nest_level > MAX_NEST_LEVEL) {
		printf("Maximum nesting (%d) exceeded\n", MAX_NEST_LEVEL);
		return -EMLINK;
	}

	while (1) {
		s = p;

		get_token(&p, &t, L_KEYWORD);

		err = 0;
		switch (t.type) {
		case T_MENU:
			err = parse_menu(&p, cfg, b, nest_level);
			break;

		case T_TIMEOUT:
			err = parse_integer(&p, &cfg->timeout);
			break;

		case T_LABEL:
			err = parse_label(&p, cfg);
			break;

		case T_DEFAULT:
			err = parse_sliteral(&p, &label_name);

			if (label_name) {
				if (cfg->default_label)
					free(cfg->default_label);

				cfg->default_label = label_name;
			}

			break;

		case T_INCLUDE:
			err = handle_include(&p, b + ALIGN(strlen(b), 4), cfg,
							nest_level + 1);
			break;

		case T_PROMPT:
			err = parse_integer(&p, &cfg->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;
	}
}

/*
 * Free the memory used by a pxe_menu and its labels.
 */
static void destroy_pxe_menu(struct pxe_menu *cfg)
{
	struct list_head *pos, *n;
	struct pxe_label *label;

	if (cfg->title)
		free(cfg->title);

	if (cfg->default_label)
		free(cfg->default_label);

	list_for_each_safe(pos, n, &cfg->labels) {
		label = list_entry(pos, struct pxe_label, list);

		label_destroy(label);
	}

	free(cfg);
}

/*
 * Entry point for parsing a pxe file. This is only used for the top level
 * file.
 *
 * Returns NULL if there is an error, otherwise, returns a pointer to a
 * pxe_menu struct populated with the results of parsing the pxe file (and any
 * files it includes). The resulting pxe_menu struct can be free()'d by using
 * the destroy_pxe_menu() function.
 */
static struct pxe_menu *parse_pxefile(char *menucfg)
{
	struct pxe_menu *cfg;

	cfg = malloc(sizeof(struct pxe_menu));

	if (!cfg)
		return NULL;

	memset(cfg, 0, sizeof(struct pxe_menu));

	INIT_LIST_HEAD(&cfg->labels);

	if (parse_pxefile_top(menucfg, cfg, 1) < 0) {
		destroy_pxe_menu(cfg);
		return NULL;
	}

	return cfg;
}

/*
 * Converts a pxe_menu struct into a menu struct for use with U-boot's generic
 * menu code.
 */
static struct menu *pxe_menu_to_menu(struct pxe_menu *cfg)
{
	struct pxe_label *label;
	struct list_head *pos;
	struct menu *m;
	int err;

	/*
	 * Create a menu and add items for all the labels.
	 */
	m = menu_create(cfg->title, cfg->timeout, cfg->prompt, label_print);

	if (!m)
		return NULL;

	list_for_each(pos, &cfg->labels) {
		label = list_entry(pos, struct pxe_label, list);

		if (menu_item_add(m, label->name, label) != 1) {
			menu_destroy(m);
			return NULL;
		}
	}

	/*
	 * After we've created items for each label in the menu, set the
	 * menu's default label if one was specified.
	 */
	if (cfg->default_label) {
		err = menu_default_set(m, cfg->default_label);
		if (err != 1) {
			if (err != -ENOENT) {
				menu_destroy(m);
				return NULL;
			}

			printf("Missing default: %s\n", cfg->default_label);
		}
	}

	return m;
}

/*
 * Try to boot any labels we have yet to attempt to boot.
 */
static void boot_unattempted_labels(struct pxe_menu *cfg)
{
	struct list_head *pos;
	struct pxe_label *label;

	list_for_each(pos, &cfg->labels) {
		label = list_entry(pos, struct pxe_label, list);

		if (!label->attempted)
			label_boot(label);
	}
}

/*
 * Boot the system as prescribed by a pxe_menu.
 *
 * Use the menu system to either get the user's choice or the default, based
 * on config or user input.  If there is no default or user's choice,
 * attempted to boot labels in the order they were given in pxe files.
 * If the default or user's choice fails to boot, attempt to boot other
 * labels in the order they were given in pxe files.
 *
 * If this function returns, there weren't any labels that successfully
 * booted, or the user interrupted the menu selection via ctrl+c.
 */
static void handle_pxe_menu(struct pxe_menu *cfg)
{
	void *choice;
	struct menu *m;
	int err;

	m = pxe_menu_to_menu(cfg);
	if (!m)
		return;

	err = menu_get_choice(m, &choice);

	menu_destroy(m);

	/*
	 * err == 1 means we got a choice back from menu_get_choice.
	 *
	 * err == -ENOENT if the menu was setup to select the default but no
	 * default was set. in that case, we should continue trying to boot
	 * labels that haven't been attempted yet.
	 *
	 * otherwise, the user interrupted or there was some other error and
	 * we give up.
	 */

	if (err == 1)
		label_boot(choice);
	else if (err != -ENOENT)
		return;

	boot_unattempted_labels(cfg);
}

/*
 * Boots a system using a pxe file
 *
 * Returns 0 on success, 1 on error.
 */
static int
do_pxe_boot(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
	unsigned long pxefile_addr_r;
	struct pxe_menu *cfg;
	char *pxefile_addr_str;

	if (argc == 1) {
		pxefile_addr_str = from_env("pxefile_addr_r");
		if (!pxefile_addr_str)
			return 1;

	} else if (argc == 2) {
		pxefile_addr_str = argv[1];
	} else {
		return CMD_RET_USAGE;
	}

	if (strict_strtoul(pxefile_addr_str, 16, &pxefile_addr_r) < 0) {
		printf("Invalid pxefile address: %s\n", pxefile_addr_str);
		return 1;
	}

	cfg = parse_pxefile((char *)(pxefile_addr_r));

	if (cfg == NULL) {
		printf("Error parsing config file\n");
		return 1;
	}

	handle_pxe_menu(cfg);

	destroy_pxe_menu(cfg);

	return 0;
}

static cmd_tbl_t cmd_pxe_sub[] = {
	U_BOOT_CMD_MKENT(get, 1, 1, do_pxe_get, "", ""),
	U_BOOT_CMD_MKENT(boot, 2, 1, do_pxe_boot, "", "")
};

int do_pxe(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
	cmd_tbl_t *cp;

	if (argc < 2)
		return CMD_RET_USAGE;

	/* drop initial "pxe" arg */
	argc--;
	argv++;

	cp = find_cmd_tbl(argv[0], cmd_pxe_sub, ARRAY_SIZE(cmd_pxe_sub));

	if (cp)
		return cp->cmd(cmdtp, flag, argc, argv);

	return CMD_RET_USAGE;
}

U_BOOT_CMD(
	pxe, 3, 1, do_pxe,
	"commands to get and boot from pxe files",
	"get - try to retrieve a pxe file using tftp\npxe "
	"boot [pxefile_addr_r] - boot from the pxe file at pxefile_addr_r\n"
);