extras/volume_id/udev_volume_id.c

   1 /*
   2  * udev_volume_id - udev callout to read filesystem label and uuid
   3  *
   4  * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
   5  *
   6  *      sample udev rule for creation of a symlink with the filsystem uuid:
   7  *      KERNEL="sd*", PROGRAM="/sbin/udev_volume_id -M%M -m%m -u", SYMLINK="%c"
   8  *
   9  *      This program is free software; you can redistribute it and/or modify it
  10  *      under the terms of the GNU General Public License as published by the
  11  *      Free Software Foundation version 2 of the License.
  12  *
  13  *      This program is distributed in the hope that it will be useful, but
  14  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  *      General Public License for more details.
  17  *
  18  *      You should have received a copy of the GNU General Public License along
  19  *      with this program; if not, write to the Free Software Foundation, Inc.,
  20  *      675 Mass Ave, Cambridge, MA 02139, USA.
  21  *
  22  */
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <unistd.h>
  27
  28 #include "volume_id.h"
  29
  30 int main(int argc, char *argv[])
  31 {
  32         struct volume_id *vid;
  33         const char help[] = "usage: udev_volume_id -m<minor> -M<major> [-t|-l|-u]\n";
  34         int major = -1;
  35         int minor = -1;
  36         char *tail;
  37         static const char short_options[] = "M:m:htlu";
  38         int option;
  39         char print = '\0';
  40         int rc;
  41
  42
  43         while (1) {
  44                 option = getopt(argc, argv, short_options);
  45                 if (option == -1)
  46                         break;
  47
  48                 switch (option) {
  49                 case 'M':
  50                         major = (int) strtoul(optarg, &tail, 10);
  51                         if (tail[0] != '\0') {
  52                                 printf("invalid major\n");
  53                                 exit(1);
  54                         }
  55                         break;
  56                 case 'm':
  57                         minor = (int) strtoul(optarg, &tail, 10);
  58                         if (tail[0] != '\0') {
  59                                 printf("invalid minor\n");
  60                                 exit(1);
  61                         }
  62                         break;
  63                 case 't':
  64                         print = 't';
  65                         break;
  66                 case 'l':
  67                         print = 'l';
  68                         break;
  69                 case 'u':
  70                         print = 'u';
  71                         break;
  72                 case 'h':
  73                 case '?':
  74                 default:
  75                         printf(help);
  76                         exit(1);
  77                 }
  78         }
  79
  80         if (major == -1 || minor == -1) {
  81                 printf(help);
  82                 exit(1);
  83         }
  84
  85         vid = volume_id_open_dev_t(makedev(major, minor));
  86         if (vid == NULL) {
  87                 printf("error open volume\n");
  88                 exit(1);
  89         }
  90
  91         rc = volume_id_probe(vid, ALL);
  92         if (rc != 0) {
  93                 printf("error probing volume\n");
  94                 exit(1);
  95         }
  96
  97         switch (print) {
  98         case 't':
  99                 printf("%s\n", vid->fs_name);
 100                 break;
 101         case 'l':
 102                 if (vid->label_string[0] == '\0')
 103                         exit(2);
 104                 printf("%s\n", vid->label_string);
 105                 break;
 106         case 'u':
 107                 if (vid->uuid_string[0] == '\0')
 108                         exit(2);
 109                 printf("%s\n", vid->uuid_string);
 110                 break;
 111         default:
 112                 printf("T:%s\n", vid->fs_name);
 113                 printf("L:%s\n", vid->label_string);
 114                 printf("U:%s\n", vid->uuid_string);
 115         }
 116
 117         volume_id_close(vid);
 118
 119         exit(0);
 120 }