sys-utils/mountpoint.c

   1 /*
   2  * mountpoint(1) - see if a directory is a mountpoint
   3  *
   4  * This is libmount based reimplementation of the mountpoit(1)
   5  * from sysvinit project.
   6  *
   7  *
   8  * Copyright (C) 2011 Red Hat, Inc. All rights reserved.
   9  * Written by Karel Zak <kzak@redhat.com>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it would be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software Foundation,
  23  * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  24  */
  25
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <errno.h>
  29 #include <string.h>
  30 #include <getopt.h>
  31 #include <unistd.h>
  32 #include <sys/types.h>
  33 #include <sys/stat.h>
  34
  35 #include <libmount.h>
  36
  37 #include "nls.h"
  38 #include "xalloc.h"
  39 #include "c.h"
  40
  41 static int quiet;
  42
  43 static char *dir_to_device(const char *spec)
  44 {
  45         struct libmnt_table *tb = mnt_new_table_from_file("/proc/self/mountinfo");
  46         struct libmnt_fs *fs;
  47         char *res = NULL;
  48
  49         if (!tb)
  50                 return NULL;
  51
  52         fs = mnt_table_find_target(tb, spec, MNT_ITER_BACKWARD);
  53         if (fs && mnt_fs_get_target(fs))
  54                 res = xstrdup(mnt_fs_get_source(fs));
  55
  56         mnt_free_table(tb);
  57         return res;
  58 }
  59
  60 static int print_devno(const char *devname, struct stat *st)
  61 {
  62         struct stat stbuf;
  63
  64         if (!st && stat(devname, &stbuf) == 0)
  65                 st = &stbuf;
  66         if (!st)
  67                 return -1;
  68         if (!S_ISBLK(st->st_mode)) {
  69                 if (!quiet)
  70                         warnx(_("%s: not a block device"), devname);
  71                 return -1;
  72         }
  73         printf("%u:%u\n", major(st->st_rdev), minor(st->st_rdev));
  74         return 0;
  75 }
  76
  77 static void __attribute__((__noreturn__)) usage(FILE *out)
  78 {
  79         fputs(_("\nUsage:\n"), out);
  80         fprintf(out,
  81               _(" %1$s [-qd] /path/to/directory\n"
  82                 " %1$s -x /dev/device\n"), program_invocation_short_name);
  83
  84         fputs(_("\nOptions:\n"), out);
  85         fputs(_(" -q, --quiet        quiet mode - don't print anything\n"
  86                 " -d, --fs-devno     print maj:min device number of the filesystem\n"
  87                 " -x, --devno        print maj:min device number of the block device\n"
  88                 " -h, --help         this help\n"), out);
  89
  90         fprintf(out, _("\nFor more information see mountpoint(1).\n"));
  91
  92         exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
  93 }
  94
  95 int main(int argc, char **argv)
  96 {
  97         int c, fs_devno = 0, dev_devno = 0, rc = 0;
  98         char *spec;
  99         struct stat st;
 100
 101         static const struct option longopts[] = {
 102                 { "quiet", 0, 0, 'q' },
 103                 { "fs-devno", 0, 0, 'd' },
 104                 { "devno", 0, 0, 'x' },
 105                 { "help", 0, 0, 'h' },
 106                 { NULL, 0, 0, 0 }
 107         };
 108
 109         setlocale(LC_ALL, "");
 110         bindtextdomain(PACKAGE, LOCALEDIR);
 111         textdomain(PACKAGE);
 112
 113         mnt_init_debug(0);
 114
 115         while ((c = getopt_long(argc, argv, "qdxh", longopts, NULL)) != -1) {
 116
 117                 switch(c) {
 118                 case 'q':
 119                         quiet = 1;
 120                         break;
 121                 case 'd':
 122                         fs_devno = 1;
 123                         break;
 124                 case 'x':
 125                         dev_devno = 1;
 126                         break;
 127                 case 'h':
 128                         usage(stdout);
 129                         break;
 130                 default:
 131                         usage(stderr);
 132                         break;
 133                 }
 134         }
 135
 136         if (optind + 1 != argc)
 137                 usage(stderr);
 138
 139         spec = argv[optind++];
 140
 141         if (stat(spec, &st)) {
 142                 if (!quiet)
 143                         err(EXIT_FAILURE, "%s", spec);
 144                 return EXIT_FAILURE;
 145         }
 146         if (dev_devno)
 147                 rc = print_devno(spec, &st);
 148         else {
 149                 char *src;
 150
 151                 if (!S_ISDIR(st.st_mode)) {
 152                         if (!quiet)
 153                                 errx(EXIT_FAILURE, _("%s: not a directory"), spec);
 154                         return EXIT_FAILURE;
 155                 }
 156                 src = dir_to_device(spec);
 157                 if (!src) {
 158                         if (!quiet)
 159                                 printf(_("%s is not a mountpoint\n"), spec);
 160                         return EXIT_FAILURE;
 161                 }
 162                 if (fs_devno)
 163                         rc = print_devno(src, NULL);
 164                 else if (!quiet)
 165                         printf(_("%s is a mountpoint\n"), spec);
 166                 free(src);
 167         }
 168
 169         return rc ? EXIT_FAILURE : EXIT_SUCCESS;
 170 }