path: root/mount/pivot_root.c

/* pivot_root.c - Change the root file system */

/* Written 2000 by Werner Almesberger */

#include <stdio.h>
#include <sys/syscall.h>
#include <unistd.h>

#define pivot_root(new_root,put_old) syscall(SYS_pivot_root,new_root,put_old)

#if 0
/*
 * With kernelheaders 2.3.41 or later, and ancient libc, try the following.
 */
#include <errno.h>
#include <linux/unistd.h>
static
_syscall2(int,pivot_root,const char *,new_root,const char *,put_old)
#endif

int main(int argc, const char **argv)
{
	if (argc != 3) {
		fprintf(stderr, "usage: %s new_root put_old\n", argv[0]);
		return 1;
	}
	if (pivot_root(argv[1],argv[2]) < 0) {
		perror("pivot_root");
		return 1;
	}
	return 0;
}