/* pivot_root.c - edit system mount tree * * Copyright 2012 Rob Landley <rob@landley.net> USE_PIVOT_ROOT(NEWTOY(pivot_root, "<2>2", TOYFLAG_USR|TOYFLAG_BIN)) config PIVOT_ROOT bool "pivot_root" default y help 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]); }