sys-utils/pivot_root.c

   1 /*
   2  * SPDX-License-Identifier: GPL-2.0-or-later
   3  *
   4  * This file is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * Copyright (C) 2000 Werner Almesberger
  10  */
  11 #include <err.h>
  12 #include <errno.h>
  13 #include <getopt.h>
  14 #include <stdio.h>
  15 #include <stdlib.h>
  16 #include <sys/syscall.h>
  17 #include <unistd.h>
  18
  19 #include "c.h"
  20 #include "nls.h"
  21 #include "closestream.h"
  22
  23 #define pivot_root(new_root,put_old) syscall(SYS_pivot_root,new_root,put_old)
  24
  25 static void __attribute__((__noreturn__)) usage(void)
  26 {
  27         FILE *out = stdout;
  28         fputs(USAGE_HEADER, out);
  29         fprintf(out, _(" %s [options] new_root put_old\n"),
  30                 program_invocation_short_name);
  31
  32         fputs(USAGE_SEPARATOR, out);
  33         fputs(_("Change the root filesystem.\n"), out);
  34
  35         fputs(USAGE_OPTIONS, out);
  36         fprintf(out, USAGE_HELP_OPTIONS(16));
  37         fprintf(out, USAGE_MAN_TAIL("pivot_root(8)"));
  38         exit(EXIT_SUCCESS);
  39 }
  40
  41 int main(int argc, char **argv)
  42 {
  43         int ch;
  44         static const struct option longopts[] = {
  45                 {"version", no_argument, NULL, 'V'},
  46                 {"help", no_argument, NULL, 'h'},
  47                 {NULL, 0, NULL, 0}
  48         };
  49
  50         setlocale(LC_ALL, "");
  51         bindtextdomain(PACKAGE, LOCALEDIR);
  52         textdomain(PACKAGE);
  53         close_stdout_atexit();
  54
  55         while ((ch = getopt_long(argc, argv, "Vh", longopts, NULL)) != -1)
  56                 switch (ch) {
  57                 case 'V':
  58                         print_version(EXIT_SUCCESS);
  59                 case 'h':
  60                         usage();
  61                 default:
  62                         errtryhelp(EXIT_FAILURE);
  63                 }
  64
  65         if (argc != 3) {
  66                 warnx(_("bad usage"));
  67                 errtryhelp(EXIT_FAILURE);
  68         }
  69         if (pivot_root(argv[1], argv[2]) < 0)
  70                 err(EXIT_FAILURE, _("failed to change root from `%s' to `%s'"),
  71                     argv[1], argv[2]);
  72
  73         return EXIT_SUCCESS;
  74 }