coreutils/chroot.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini chroot implementation for busybox
   4  *
   5  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
   6  *
   7  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8  */
   9 //config:config CHROOT
  10 //config:       bool "chroot (4 kb)"
  11 //config:       default y
  12 //config:       help
  13 //config:       chroot is used to change the root directory and run a command.
  14 //config:       The default command is '/bin/sh'.
  15
  16 //applet:IF_CHROOT(APPLET_NOEXEC(chroot, chroot, BB_DIR_USR_SBIN, BB_SUID_DROP, chroot))
  17
  18 //kbuild:lib-$(CONFIG_CHROOT) += chroot.o
  19
  20 /* BB_AUDIT SUSv3 N/A -- Matches GNU behavior. */
  21
  22 //usage:#define chroot_trivial_usage
  23 //usage:       "NEWROOT [PROG ARGS]"
  24 //usage:#define chroot_full_usage "\n\n"
  25 //usage:       "Run PROG with root directory set to NEWROOT"
  26 //usage:
  27 //usage:#define chroot_example_usage
  28 //usage:       "$ ls -l /bin/ls\n"
  29 //usage:       "lrwxrwxrwx    1 root     root          12 Apr 13 00:46 /bin/ls -> /BusyBox\n"
  30 //usage:       "# mount /dev/hdc1 /mnt -t minix\n"
  31 //usage:       "# chroot /mnt\n"
  32 //usage:       "# ls -l /bin/ls\n"
  33 //usage:       "-rwxr-xr-x    1 root     root        40816 Feb  5 07:45 /bin/ls*\n"
  34
  35 #include "libbb.h"
  36
  37 int chroot_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  38 int chroot_main(int argc UNUSED_PARAM, char **argv)
  39 {
  40         ++argv;
  41         if (!*argv)
  42                 bb_show_usage();
  43
  44         xchroot(*argv);
  45
  46         ++argv;
  47         if (!*argv) { /* no 2nd param (PROG), use shell */
  48                 argv -= 2;
  49                 argv[0] = (char *) get_shell_name();
  50                 argv[1] = (char *) "-i"; /* GNU coreutils 8.4 compat */
  51                 /*argv[2] = NULL; - already is */
  52         }
  53
  54         BB_EXECVP_or_die(argv);
  55 }