view toys/other/pivot_root.c @ 1322:b91284c2e569 draft

Make "losetup /dev/loop0 filename" work. Sigh. Implement the complex cases and you screw up the simple cases you already tested...
author Rob Landley <>
date Thu, 29 May 2014 06:29:12 -0500
parents 9e00446064fa
children da72fa267b7b
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/* pivot_root.c - edit system mount tree
 * Copyright 2012 Rob Landley <>


  bool "pivot_root"
  default y
    usage: pivot_root OLD NEW

    Swap OLD and NEW filesystems (as if by simultaneous mount --move), and
    move all processes with chdir or chroot under OLD into NEW (including
    kernel threads) so OLD may be unmounted.

    The directory NEW must exist under OLD. This doesn't work on initramfs,
    which can't be moved (about the same way PID 1 can't be killed; see
    switch_root instead).

#define FOR_pivot_root
#include "toys.h"

#include <linux/unistd.h>

void pivot_root_main(void)
  if (syscall(__NR_pivot_root, toys.optargs[0], toys.optargs[1]))
    perror_exit("'%s' -> '%s'", toys.optargs[0], toys.optargs[1]);