common/cli.c

/*
 * (C) Copyright 2000
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * Add to readline cmdline-editing by
 * (C) Copyright 2005
 * JinHua Luo, GuangDong Linux Center, <luo.jinhua@gd-linux.com>
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#include <common.h>
#include <cli.h>
#include <cli_hush.h>
#include <fdtdec.h>
#include <malloc.h>

DECLARE_GLOBAL_DATA_PTR;

/*
 * Run a command using the selected parser.
 *
 * @param cmd	Command to run
 * @param flag	Execution flags (CMD_FLAG_...)
 * @return 0 on success, or != 0 on error.
 */
int run_command(const char *cmd, int flag)
{
#ifndef CONFIG_SYS_HUSH_PARSER
	/*
	 * cli_run_command can return 0 or 1 for success, so clean up
	 * its result.
	 */
	if (cli_simple_run_command(cmd, flag) == -1)
		return 1;

	return 0;
#else
	int hush_flags = FLAG_PARSE_SEMICOLON | FLAG_EXIT_FROM_LOOP;

	if (flag & CMD_FLAG_ENV)
		hush_flags |= FLAG_CONT_ON_NEWLINE;
	return parse_string_outer(cmd, hush_flags);
#endif
}

/*
 * Run a command using the selected parser, and check if it is repeatable.
 *
 * @param cmd	Command to run
 * @param flag	Execution flags (CMD_FLAG_...)
 * @return 0 (not repeatable) or 1 (repeatable) on success, -1 on error.
 */
int run_command_repeatable(const char *cmd, int flag)
{
#ifndef CONFIG_SYS_HUSH_PARSER
	return cli_simple_run_command(cmd, flag);
#else
	/*
	 * parse_string_outer() returns 1 for failure, so clean up
	 * its result.
	 */
	if (parse_string_outer(cmd,
			       FLAG_PARSE_SEMICOLON | FLAG_EXIT_FROM_LOOP))
		return -1;

	return 0;
#endif
}

int run_command_list(const char *cmd, int len, int flag)
{
	int need_buff = 1;
	char *buff = (char *)cmd;	/* cast away const */
	int rcode = 0;

	if (len == -1) {
		len = strlen(cmd);
#ifdef CONFIG_SYS_HUSH_PARSER
		/* hush will never change our string */
		need_buff = 0;
#else
		/* the built-in parser will change our string if it sees \n */
		need_buff = strchr(cmd, '\n') != NULL;
#endif
	}
	if (need_buff) {
		buff = malloc(len + 1);
		if (!buff)
			return 1;
		memcpy(buff, cmd, len);
		buff[len] = '\0';
	}
#ifdef CONFIG_SYS_HUSH_PARSER
	rcode = parse_string_outer(buff, FLAG_PARSE_SEMICOLON);
#else
	/*
	 * This function will overwrite any \n it sees with a \0, which
	 * is why it can't work with a const char *. Here we are making
	 * using of internal knowledge of this function, to avoid always
	 * doing a malloc() which is actually required only in a case that
	 * is pretty rare.
	 */
	rcode = cli_simple_run_command_list(buff, flag);
	if (need_buff)
		free(buff);
#endif

	return rcode;
}

/****************************************************************************/

#if defined(CONFIG_CMD_RUN)
int do_run(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
	int i;

	if (argc < 2)
		return CMD_RET_USAGE;

	for (i = 1; i < argc; ++i) {
		char *arg;

		arg = getenv(argv[i]);
		if (arg == NULL) {
			printf("## Error: \"%s\" not defined\n", argv[i]);
			return 1;
		}

		if (run_command(arg, flag | CMD_FLAG_ENV) != 0)
			return 1;
	}
	return 0;
}
#endif

#if CONFIG_IS_ENABLED(OF_CONTROL)
bool cli_process_fdt(const char **cmdp)
{
	/* Allow the fdt to override the boot command */
	char *env = fdtdec_get_config_string(gd->fdt_blob, "bootcmd");
	if (env)
		*cmdp = env;
	/*
	 * 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.
	 */
	return fdtdec_get_config_int(gd->fdt_blob, "bootsecure", 0) != 0;
}

/*
 * 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.
 */
void cli_secure_boot_cmd(const 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, (char **)&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();
}
#endif /* CONFIG_IS_ENABLED(OF_CONTROL) */

void cli_loop(void)
{
#ifdef CONFIG_SYS_HUSH_PARSER
	parse_file_outer();
	/* This point is never reached */
	for (;;);
#else
	cli_simple_loop();
#endif /*CONFIG_SYS_HUSH_PARSER*/
}

void cli_init(void)
{
#ifdef CONFIG_SYS_HUSH_PARSER
	u_boot_hush_start();
#endif

#if defined(CONFIG_HUSH_INIT_VAR)
	hush_init_var();
#endif
}