util-linux/sys-utils/pivot_root.c

80 lines
1.9 KiB
C

/*
* pivot_root.c - Change the root file system
*
* Copyright (C) 2000 Werner Almesberger
*
* This file is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This file is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <err.h>
#include <errno.h>
#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/syscall.h>
#include <unistd.h>
#include "c.h"
#include "nls.h"
#include "closestream.h"
#define pivot_root(new_root,put_old) syscall(SYS_pivot_root,new_root,put_old)
static void __attribute__((__noreturn__)) usage(void)
{
FILE *out = stdout;
fputs(USAGE_HEADER, out);
fprintf(out, _(" %s [options] new_root put_old\n"),
program_invocation_short_name);
fputs(USAGE_SEPARATOR, out);
fputs(_("Change the root filesystem.\n"), out);
fputs(USAGE_OPTIONS, out);
printf(USAGE_HELP_OPTIONS(16));
printf(USAGE_MAN_TAIL("pivot_root(8)"));
exit(EXIT_SUCCESS);
}
int main(int argc, char **argv)
{
int ch;
static const struct option longopts[] = {
{"version", no_argument, NULL, 'V'},
{"help", no_argument, NULL, 'h'},
{NULL, 0, NULL, 0}
};
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
close_stdout_atexit();
while ((ch = getopt_long(argc, argv, "Vh", longopts, NULL)) != -1)
switch (ch) {
case 'V':
print_version(EXIT_SUCCESS);
case 'h':
usage();
default:
errtryhelp(EXIT_FAILURE);
}
if (argc != 3) {
warnx(_("bad usage"));
errtryhelp(EXIT_FAILURE);
}
if (pivot_root(argv[1], argv[2]) < 0)
err(EXIT_FAILURE, _("failed to change root from `%s' to `%s'"),
argv[1], argv[2]);
return EXIT_SUCCESS;
}