u-boot/common/autoboot.c

/*
 * (C) Copyright 2000
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#include <common.h>
#include <cli.h>
#include <fdtdec.h>
#include <menu.h>
#include <post.h>

DECLARE_GLOBAL_DATA_PTR;

#define MAX_DELAY_STOP_STR 32

#ifndef DEBUG_BOOTKEYS
#define DEBUG_BOOTKEYS 0
#endif
#define debug_bootkeys(fmt, args...)		\
	debug_cond(DEBUG_BOOTKEYS, fmt, ##args)

/***************************************************************************
 * Watch for 'delay' seconds for autoboot stop or autoboot delay string.
 * returns: 0 -  no key string, allow autoboot 1 - got key string, abort
 */
# if defined(CONFIG_AUTOBOOT_KEYED)
static int abortboot_keyed(int bootdelay)
{
	int abort = 0;
	uint64_t etime = endtick(bootdelay);
	struct {
		char *str;
		u_int len;
		int retry;
	}
	delaykey[] = {
		{ str: getenv("bootdelaykey"),  retry: 1 },
		{ str: getenv("bootdelaykey2"), retry: 1 },
		{ str: getenv("bootstopkey"),   retry: 0 },
		{ str: getenv("bootstopkey2"),  retry: 0 },
	};

	char presskey[MAX_DELAY_STOP_STR];
	u_int presskey_len = 0;
	u_int presskey_max = 0;
	u_int i;

#ifndef CONFIG_ZERO_BOOTDELAY_CHECK
	if (bootdelay == 0)
		return 0;
#endif

#  ifdef CONFIG_AUTOBOOT_PROMPT
	printf(CONFIG_AUTOBOOT_PROMPT);
#  endif

#  ifdef CONFIG_AUTOBOOT_DELAY_STR
	if (delaykey[0].str == NULL)
		delaykey[0].str = CONFIG_AUTOBOOT_DELAY_STR;
#  endif
#  ifdef CONFIG_AUTOBOOT_DELAY_STR2
	if (delaykey[1].str == NULL)
		delaykey[1].str = CONFIG_AUTOBOOT_DELAY_STR2;
#  endif
#  ifdef CONFIG_AUTOBOOT_STOP_STR
	if (delaykey[2].str == NULL)
		delaykey[2].str = CONFIG_AUTOBOOT_STOP_STR;
#  endif
#  ifdef CONFIG_AUTOBOOT_STOP_STR2
	if (delaykey[3].str == NULL)
		delaykey[3].str = CONFIG_AUTOBOOT_STOP_STR2;
#  endif

	for (i = 0; i < sizeof(delaykey) / sizeof(delaykey[0]); i++) {
		delaykey[i].len = delaykey[i].str == NULL ?
				    0 : strlen(delaykey[i].str);
		delaykey[i].len = delaykey[i].len > MAX_DELAY_STOP_STR ?
				    MAX_DELAY_STOP_STR : delaykey[i].len;

		presskey_max = presskey_max > delaykey[i].len ?
				    presskey_max : delaykey[i].len;

		debug_bootkeys("%s key:<%s>\n",
			       delaykey[i].retry ? "delay" : "stop",
			       delaykey[i].str ? delaykey[i].str : "NULL");
	}

	/* In order to keep up with incoming data, check timeout only
	 * when catch up.
	 */
	do {
		if (tstc()) {
			if (presskey_len < presskey_max) {
				presskey[presskey_len++] = getc();
			} else {
				for (i = 0; i < presskey_max - 1; i++)
					presskey[i] = presskey[i + 1];

				presskey[i] = getc();
			}
		}

		for (i = 0; i < sizeof(delaykey) / sizeof(delaykey[0]); i++) {
			if (delaykey[i].len > 0 &&
			    presskey_len >= delaykey[i].len &&
				memcmp(presskey + presskey_len -
					delaykey[i].len, delaykey[i].str,
					delaykey[i].len) == 0) {
					debug_bootkeys("got %skey\n",
						delaykey[i].retry ? "delay" :
						"stop");

#  ifdef CONFIG_BOOT_RETRY_TIME
				/* don't retry auto boot */
				if (!delaykey[i].retry)
					bootretry_dont_retry();
#  endif
				abort = 1;
			}
		}
	} while (!abort && get_ticks() <= etime);

	if (!abort)
		debug_bootkeys("key timeout\n");

#ifdef CONFIG_SILENT_CONSOLE
	if (abort)
		gd->flags &= ~GD_FLG_SILENT;
#endif

	return abort;
}

# else	/* !defined(CONFIG_AUTOBOOT_KEYED) */

#ifdef CONFIG_MENUKEY
static int menukey;
#endif

static int abortboot_normal(int bootdelay)
{
	int abort = 0;
	unsigned long ts;

#ifdef CONFIG_MENUPROMPT
	printf(CONFIG_MENUPROMPT);
#else
	if (bootdelay >= 0)
		printf("Hit any key to stop autoboot: %2d ", bootdelay);
#endif

#if defined CONFIG_ZERO_BOOTDELAY_CHECK
	/*
	 * Check if key already pressed
	 * Don't check if bootdelay < 0
	 */
	if (bootdelay >= 0) {
		if (tstc()) {	/* we got a key press	*/
			(void) getc();  /* consume input	*/
			puts("\b\b\b 0");
			abort = 1;	/* don't auto boot	*/
		}
	}
#endif

	while ((bootdelay > 0) && (!abort)) {
		--bootdelay;
		/* delay 1000 ms */
		ts = get_timer(0);
		do {
			if (tstc()) {	/* we got a key press	*/
				abort  = 1;	/* don't auto boot	*/
				bootdelay = 0;	/* no more delay	*/
# ifdef CONFIG_MENUKEY
				menukey = getc();
# else
				(void) getc();  /* consume input	*/
# endif
				break;
			}
			udelay(10000);
		} while (!abort && get_timer(ts) < 1000);

		printf("\b\b\b%2d ", bootdelay);
	}

	putc('\n');

#ifdef CONFIG_SILENT_CONSOLE
	if (abort)
		gd->flags &= ~GD_FLG_SILENT;
#endif

	return abort;
}
# endif	/* CONFIG_AUTOBOOT_KEYED */

static int abortboot(int bootdelay)
{
#ifdef CONFIG_AUTOBOOT_KEYED
	return abortboot_keyed(bootdelay);
#else
	return abortboot_normal(bootdelay);
#endif
}

/*
 * Runs the given boot command securely.  Specifically:
 * - Doesn't run the command with the shell (run_command or parse_string_outer),
 *   since that's a lot of code surface that an attacker might exploit.
 *   Because of this, we don't do any argument parsing--the secure boot command
 *   has to be a full-fledged u-boot command.
 * - Doesn't check for keypresses before booting, since that could be a
 *   security hole; also disables Ctrl-C.
 * - Doesn't allow the command to return.
 *
 * Upon any failures, this function will drop into an infinite loop after
 * printing the error message to console.
 */

#if defined(CONFIG_OF_CONTROL)
static void secure_boot_cmd(char *cmd)
{
	cmd_tbl_t *cmdtp;
	int rc;

	if (!cmd) {
		printf("## Error: Secure boot command not specified\n");
		goto err;
	}

	/* Disable Ctrl-C just in case some command is used that checks it. */
	disable_ctrlc(1);

	/* Find the command directly. */
	cmdtp = find_cmd(cmd);
	if (!cmdtp) {
		printf("## Error: \"%s\" not defined\n", cmd);
		goto err;
	}

	/* Run the command, forcing no flags and faking argc and argv. */
	rc = (cmdtp->cmd)(cmdtp, 0, 1, &cmd);

	/* Shouldn't ever return from boot command. */
	printf("## Error: \"%s\" returned (code %d)\n", cmd, rc);

err:
	/*
	 * Not a whole lot to do here.  Rebooting won't help much, since we'll
	 * just end up right back here.  Just loop.
	 */
	hang();
}

static void process_fdt_options(const void *blob)
{
	ulong addr;

	/* Add an env variable to point to a kernel payload, if available */
	addr = fdtdec_get_config_int(gd->fdt_blob, "kernel-offset", 0);
	if (addr)
		setenv_addr("kernaddr", (void *)(CONFIG_SYS_TEXT_BASE + addr));

	/* Add an env variable to point to a root disk, if available */
	addr = fdtdec_get_config_int(gd->fdt_blob, "rootdisk-offset", 0);
	if (addr)
		setenv_addr("rootaddr", (void *)(CONFIG_SYS_TEXT_BASE + addr));
}
#endif /* CONFIG_OF_CONTROL */

void bootdelay_process(void)
{
#ifdef CONFIG_OF_CONTROL
	char *env;
#endif
	char *s;
	int bootdelay;
#ifdef CONFIG_BOOTCOUNT_LIMIT
	unsigned long bootcount = 0;
	unsigned long bootlimit = 0;
#endif /* CONFIG_BOOTCOUNT_LIMIT */

#ifdef CONFIG_BOOTCOUNT_LIMIT
	bootcount = bootcount_load();
	bootcount++;
	bootcount_store(bootcount);
	setenv_ulong("bootcount", bootcount);
	bootlimit = getenv_ulong("bootlimit", 10, 0);
#endif /* CONFIG_BOOTCOUNT_LIMIT */

	s = getenv("bootdelay");
	bootdelay = s ? (int)simple_strtol(s, NULL, 10) : CONFIG_BOOTDELAY;

#ifdef CONFIG_OF_CONTROL
	bootdelay = fdtdec_get_config_int(gd->fdt_blob, "bootdelay",
			bootdelay);
#endif

	debug("### main_loop entered: bootdelay=%d\n\n", bootdelay);

#if defined(CONFIG_MENU_SHOW)
	bootdelay = menu_show(bootdelay);
#endif
# ifdef CONFIG_BOOT_RETRY_TIME
	init_cmd_timeout();
# endif	/* CONFIG_BOOT_RETRY_TIME */

#ifdef CONFIG_POST
	if (gd->flags & GD_FLG_POSTFAIL) {
		s = getenv("failbootcmd");
	} else
#endif /* CONFIG_POST */
#ifdef CONFIG_BOOTCOUNT_LIMIT
	if (bootlimit && (bootcount > bootlimit)) {
		printf("Warning: Bootlimit (%u) exceeded. Using altbootcmd.\n",
		       (unsigned)bootlimit);
		s = getenv("altbootcmd");
	} else
#endif /* CONFIG_BOOTCOUNT_LIMIT */
		s = getenv("bootcmd");
#ifdef CONFIG_OF_CONTROL
	/* Allow the fdt to override the boot command */
	env = fdtdec_get_config_string(gd->fdt_blob, "bootcmd");
	if (env)
		s = env;

	process_fdt_options(gd->fdt_blob);

	/*
	 * If the bootsecure option was chosen, use secure_boot_cmd().
	 * Always use 'env' in this case, since bootsecure requres that the
	 * bootcmd was specified in the FDT too.
	 */
	if (fdtdec_get_config_int(gd->fdt_blob, "bootsecure", 0))
		secure_boot_cmd(env);

#endif /* CONFIG_OF_CONTROL */

	debug("### main_loop: bootcmd=\"%s\"\n", s ? s : "<UNDEFINED>");

	if (bootdelay != -1 && s && !abortboot(bootdelay)) {
#if defined(CONFIG_AUTOBOOT_KEYED) && !defined(CONFIG_AUTOBOOT_KEYED_CTRLC)
		int prev = disable_ctrlc(1);	/* disable Control C checking */
#endif

		run_command_list(s, -1, 0);

#if defined(CONFIG_AUTOBOOT_KEYED) && !defined(CONFIG_AUTOBOOT_KEYED_CTRLC)
		disable_ctrlc(prev);	/* restore Control C checking */
#endif
	}

#ifdef CONFIG_MENUKEY
	if (menukey == CONFIG_MENUKEY) {
		s = getenv("menucmd");
		if (s)
			run_command_list(s, -1, 0);
	}
#endif /* CONFIG_MENUKEY */
}