busybox/coreutils/chroot.c

/* vi: set sw=4 ts=4: */
/*
 * Mini chroot implementation for busybox
 *
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
//config:config CHROOT
//config:	bool "chroot (4 kb)"
//config:	default y
//config:	help
//config:	chroot is used to change the root directory and run a command.
//config:	The default command is '/bin/sh'.

//applet:IF_CHROOT(APPLET_NOEXEC(chroot, chroot, BB_DIR_USR_SBIN, BB_SUID_DROP, chroot))

//kbuild:lib-$(CONFIG_CHROOT) += chroot.o

/* BB_AUDIT SUSv3 N/A -- Matches GNU behavior. */

//usage:#define chroot_trivial_usage
//usage:       "NEWROOT [PROG ARGS]"
//usage:#define chroot_full_usage "\n\n"
//usage:       "Run PROG with root directory set to NEWROOT"
//usage:
//usage:#define chroot_example_usage
//usage:       "$ ls -l /bin/ls\n"
//usage:       "lrwxrwxrwx    1 root     root          12 Apr 13 00:46 /bin/ls -> /BusyBox\n"
//usage:       "# mount /dev/hdc1 /mnt -t minix\n"
//usage:       "# chroot /mnt\n"
//usage:       "# ls -l /bin/ls\n"
//usage:       "-rwxr-xr-x    1 root     root        40816 Feb  5 07:45 /bin/ls*\n"

#include "libbb.h"

int chroot_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int chroot_main(int argc UNUSED_PARAM, char **argv)
{
	++argv;
	if (!*argv)
		bb_show_usage();

	xchroot(*argv);

	++argv;
	if (!*argv) { /* no 2nd param (PROG), use shell */
		argv -= 2;
		argv[0] = (char *) get_shell_name();
		argv[1] = (char *) "-i"; /* GNU coreutils 8.4 compat */
		/*argv[2] = NULL; - already is */
	}

	BB_EXECVP_or_die(argv);
}