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/* vi: set sw=4 ts=4: */
/*
* pivot_root.c - Change root file system. Based on util-linux 2.10s
*
* busyboxed by Evin Robertson
* pivot_root syscall stubbed by Erik Andersen, so it will compile
* regardless of the kernel being used.
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
//config:config PIVOT_ROOT
//config: bool "pivot_root (1.1 kb)"
//config: default y
//config: help
//config: The pivot_root utility swaps the mount points for the root filesystem
//config: with some other mounted filesystem. This allows you to do all sorts
//config: of wild and crazy things with your Linux system and is far more
//config: powerful than 'chroot'.
//config:
//config: Note: This is for initrd in linux 2.4. Under initramfs (introduced
//config: in linux 2.6) use switch_root instead.
//applet:IF_PIVOT_ROOT(APPLET_NOFORK(pivot_root, pivot_root, BB_DIR_SBIN, BB_SUID_DROP, pivot_root))
//kbuild:lib-$(CONFIG_PIVOT_ROOT) += pivot_root.o
//usage:#define pivot_root_trivial_usage
//usage: "NEW_ROOT PUT_OLD"
//usage:#define pivot_root_full_usage "\n\n"
//usage: "Move the current root file system to PUT_OLD and make NEW_ROOT\n"
//usage: "the new root file system"
#include "libbb.h"
extern int pivot_root(const char *new_root, const char *put_old);
int pivot_root_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int pivot_root_main(int argc, char **argv)
{
if (argc != 3)
bb_show_usage();
/* NOFORK applet. Hardly matters wrt performance, but code is trivial */
if (pivot_root(argv[1], argv[2]) < 0) {
/* prints "pivot_root: <strerror text>" */
bb_perror_nomsg_and_die();
}
return EXIT_SUCCESS;
}
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