extras/volume_id/vol_id.c

   1 /*
   2  * vol_id - read filesystem label and uuid
   3  *
   4  * Copyright (C) 2005-2006 Kay Sievers <kay.sievers@vrfy.org>
   5  *
   6  *      This program is free software; you can redistribute it and/or modify it
   7  *      under the terms of the GNU General Public License as published by the
   8  *      Free Software Foundation version 2 of the License.
   9  *
  10  *      This program is distributed in the hope that it will be useful, but
  11  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  *      General Public License for more details.
  14  *
  15  *      You should have received a copy of the GNU General Public License along
  16  *      with this program; if not, write to the Free Software Foundation, Inc.,
  17  *      675 Mass Ave, Cambridge, MA 02139, USA.
  18  *
  19  */
  20
  21 #ifndef _GNU_SOURCE
  22 #define _GNU_SOURCE 1
  23 #endif
  24
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <unistd.h>
  28 #include <string.h>
  29 #include <ctype.h>
  30 #include <grp.h>
  31 #include <sys/ioctl.h>
  32
  33 #include "../../udev.h"
  34 #include "lib/libvolume_id.h"
  35
  36 #define BLKGETSIZE64 _IOR(0x12,114,size_t)
  37
  38 #ifdef USE_LOG
  39 void log_message(int priority, const char *format, ...)
  40 {
  41         va_list args;
  42         static int udev_log = -1;
  43
  44         if (udev_log == -1) {
  45                 const char *value;
  46
  47                 value = getenv("UDEV_LOG");
  48                 if (value)
  49                         udev_log = log_priority(value);
  50                 else
  51                         udev_log = LOG_ERR;
  52         }
  53
  54         if (priority > udev_log)
  55                 return;
  56
  57         va_start(args, format);
  58         vsyslog(priority, format, args);
  59         va_end(args);
  60 }
  61 #endif
  62
  63 static void vid_log(int priority, const char *file, int line, const char *format, ...)
  64 {
  65 #ifdef USE_LOG
  66         va_list args;
  67
  68         va_start(args, format);
  69         log_message(priority, format, args);
  70         va_end(args);
  71 #endif
  72         return;
  73 }
  74
  75 static void set_str(char *to, const char *from, size_t count)
  76 {
  77         size_t i, j, len;
  78
  79         /* strip trailing whitespace */
  80         len = strnlen(from, count);
  81         while (len && isspace(from[len-1]))
  82                 len--;
  83
  84         /* strip leading whitespace */
  85         i = 0;
  86         while (isspace(from[i]) && (i < len))
  87                 i++;
  88
  89         j = 0;
  90         while (i < len) {
  91                 /* substitute multiple whitespace */
  92                 if (isspace(from[i])) {
  93                         while (isspace(from[i]))
  94                                 i++;
  95                         to[j++] = '_';
  96                 }
  97                 /* skip chars */
  98                 if (from[i] == '/') {
  99                         i++;
 100                         continue;
 101                 }
 102                 to[j++] = from[i++];
 103         }
 104         to[j] = '\0';
 105 }
 106
 107 int main(int argc, char *argv[])
 108 {
 109         const char help[] = "usage: vol_id [--export|-t|-l|-u] <device>\n"
 110                             "       --export\n"
 111                             "       -t filesystem type\n"
 112                             "       -l filesystem label\n"
 113                             "       -u filesystem uuid\n"
 114                             "\n";
 115         enum print_type {
 116                 PRINT_EXPORT,
 117                 PRINT_TYPE,
 118                 PRINT_LABEL,
 119                 PRINT_UUID,
 120         } print = PRINT_EXPORT;
 121         struct volume_id *vid = NULL;
 122         static char name[VOLUME_ID_LABEL_SIZE];
 123         int i;
 124         uint64_t size;
 125         const char *node = NULL;
 126         uid_t nobody_uid;
 127         gid_t nobody_gid;
 128         int rc = 0;
 129
 130         logging_init("vol_id");
 131
 132         /* hook in our debug into libvolume_id */
 133         volume_id_log_fn = vid_log;
 134
 135         for (i = 1 ; i < argc; i++) {
 136                 char *arg = argv[i];
 137
 138                 if (strcmp(arg, "--export") == 0) {
 139                         print = PRINT_EXPORT;
 140                 } else if (strcmp(arg, "-t") == 0) {
 141                         print = PRINT_TYPE;
 142                 } else if (strcmp(arg, "-l") == 0) {
 143                         print = PRINT_LABEL;
 144                 } else if (strcmp(arg, "-u") == 0) {
 145                         print = PRINT_UUID;
 146                 } else
 147                         node = arg;
 148         }
 149         if (!node) {
 150                 err("no node specified");
 151                 fprintf(stderr, help);
 152                 rc = 1;
 153                 goto exit;
 154         }
 155
 156         vid = volume_id_open_node(node);
 157         if (vid == NULL) {
 158                 fprintf(stderr, "%s: error open volume\n", node);
 159                 rc = 2;
 160                 goto exit;
 161         }
 162
 163         if (ioctl(vid->fd, BLKGETSIZE64, &size) != 0)
 164                 size = 0;
 165         dbg("BLKGETSIZE64=%llu", size);
 166
 167         /* drop all privileges */
 168         nobody_uid = lookup_user("nobody");
 169         nobody_gid = lookup_group("nogroup");
 170         if (nobody_uid > 0 && nobody_gid > 0) {
 171                 if (setgroups(0, NULL) != 0 ||
 172                     setgid(nobody_gid) != 0 ||
 173                     setuid(nobody_uid) != 0) {
 174                         rc = 3;
 175                         goto exit;
 176                 }
 177         }
 178
 179         if (volume_id_probe_all(vid, 0, size) == 0)
 180                 goto print;
 181
 182         if (print != PRINT_EXPORT)
 183                 fprintf(stderr, "%s: unknown volume type\n", node);
 184         rc = 4;
 185         goto exit;
 186
 187 print:
 188         set_str(name, vid->label, sizeof(vid->label));
 189         replace_untrusted_chars(name);
 190
 191         switch (print) {
 192         case PRINT_EXPORT:
 193                 printf("ID_FS_USAGE=%s\n", vid->usage);
 194                 printf("ID_FS_TYPE=%s\n", vid->type);
 195                 printf("ID_FS_VERSION=%s\n", vid->type_version);
 196                 printf("ID_FS_UUID=%s\n", vid->uuid);
 197                 printf("ID_FS_LABEL=%s\n", vid->label);
 198                 printf("ID_FS_LABEL_SAFE=%s\n", name);
 199                 break;
 200         case PRINT_TYPE:
 201                 printf("%s\n", vid->type);
 202                 break;
 203         case PRINT_LABEL:
 204                 if (name[0] == '\0' ||
 205                     (vid->usage_id != VOLUME_ID_FILESYSTEM && vid->usage_id != VOLUME_ID_DISKLABEL)) {
 206                         rc = 3;
 207                         goto exit;
 208                 }
 209                 printf("%s\n", name);
 210                 break;
 211         case PRINT_UUID:
 212                 if (vid->uuid[0] == '\0' || vid->usage_id != VOLUME_ID_FILESYSTEM) {
 213                         rc = 4;
 214                         goto exit;
 215                 }
 216                 printf("%s\n", vid->uuid);
 217                 break;
 218         }
 219
 220 exit:
 221         if (vid != NULL)
 222                 volume_id_close(vid);
 223
 224         logging_close();
 225         return rc;
 226 }