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         char log_str[1024];
  67         va_list args;
  68
  69         va_start(args, format);
  70         vsnprintf(log_str, sizeof(log_str), format, args);
  71         log_str[sizeof(log_str)-1] = '\0';
  72         log_message(priority, "%s:%i %s", file, line, log_str);
  73         va_end(args);
  74 #endif
  75         return;
  76 }
  77
  78 static void set_str(char *to, const char *from, size_t count)
  79 {
  80         size_t i, j, len;
  81
  82         /* strip trailing whitespace */
  83         len = strnlen(from, count);
  84         while (len && isspace(from[len-1]))
  85                 len--;
  86
  87         /* strip leading whitespace */
  88         i = 0;
  89         while (isspace(from[i]) && (i < len))
  90                 i++;
  91
  92         j = 0;
  93         while (i < len) {
  94                 /* substitute multiple whitespace */
  95                 if (isspace(from[i])) {
  96                         while (isspace(from[i]))
  97                                 i++;
  98                         to[j++] = '_';
  99                 }
 100                 /* skip chars */
 101                 if (from[i] == '/') {
 102                         i++;
 103                         continue;
 104                 }
 105                 to[j++] = from[i++];
 106         }
 107         to[j] = '\0';
 108 }
 109
 110 int main(int argc, char *argv[])
 111 {
 112         const char help[] = "usage: vol_id [--export|-t|-l|-u] <device>\n"
 113                             "       --export\n"
 114                             "       -t filesystem type\n"
 115                             "       -l filesystem label\n"
 116                             "       -u filesystem uuid\n"
 117                             "\n";
 118         enum print_type {
 119                 PRINT_EXPORT,
 120                 PRINT_TYPE,
 121                 PRINT_LABEL,
 122                 PRINT_UUID,
 123         } print = PRINT_EXPORT;
 124         struct volume_id *vid = NULL;
 125         static char name[VOLUME_ID_LABEL_SIZE];
 126         int i;
 127         uint64_t size;
 128         const char *node = NULL;
 129         uid_t nobody_uid;
 130         gid_t nobody_gid;
 131         int rc = 0;
 132
 133         logging_init("vol_id");
 134
 135         /* hook in our debug into libvolume_id */
 136         volume_id_log_fn = vid_log;
 137
 138         for (i = 1 ; i < argc; i++) {
 139                 char *arg = argv[i];
 140
 141                 if (strcmp(arg, "--export") == 0) {
 142                         print = PRINT_EXPORT;
 143                 } else if (strcmp(arg, "-t") == 0) {
 144                         print = PRINT_TYPE;
 145                 } else if (strcmp(arg, "-l") == 0) {
 146                         print = PRINT_LABEL;
 147                 } else if (strcmp(arg, "-u") == 0) {
 148                         print = PRINT_UUID;
 149                 } else
 150                         node = arg;
 151         }
 152         if (!node) {
 153                 err("no node specified");
 154                 fprintf(stderr, help);
 155                 rc = 1;
 156                 goto exit;
 157         }
 158
 159         vid = volume_id_open_node(node);
 160         if (vid == NULL) {
 161                 fprintf(stderr, "%s: error open volume\n", node);
 162                 rc = 2;
 163                 goto exit;
 164         }
 165
 166         if (ioctl(vid->fd, BLKGETSIZE64, &size) != 0)
 167                 size = 0;
 168         dbg("BLKGETSIZE64=%llu", size);
 169
 170         /* drop all privileges */
 171         nobody_uid = lookup_user("nobody");
 172         nobody_gid = lookup_group("nogroup");
 173         if (nobody_uid > 0 && nobody_gid > 0) {
 174                 if (setgroups(0, NULL) != 0 ||
 175                     setgid(nobody_gid) != 0 ||
 176                     setuid(nobody_uid) != 0) {
 177                         rc = 3;
 178                         goto exit;
 179                 }
 180         }
 181
 182         if (volume_id_probe_all(vid, 0, size) == 0)
 183                 goto print;
 184
 185         if (print != PRINT_EXPORT)
 186                 fprintf(stderr, "%s: unknown volume type\n", node);
 187         rc = 4;
 188         goto exit;
 189
 190 print:
 191         set_str(name, vid->label, sizeof(vid->label));
 192         replace_untrusted_chars(name);
 193
 194         switch (print) {
 195         case PRINT_EXPORT:
 196                 printf("ID_FS_USAGE=%s\n", vid->usage);
 197                 printf("ID_FS_TYPE=%s\n", vid->type);
 198                 printf("ID_FS_VERSION=%s\n", vid->type_version);
 199                 printf("ID_FS_UUID=%s\n", vid->uuid);
 200                 printf("ID_FS_LABEL=%s\n", vid->label);
 201                 printf("ID_FS_LABEL_SAFE=%s\n", name);
 202                 break;
 203         case PRINT_TYPE:
 204                 printf("%s\n", vid->type);
 205                 break;
 206         case PRINT_LABEL:
 207                 if (name[0] == '\0' ||
 208                     (vid->usage_id != VOLUME_ID_FILESYSTEM && vid->usage_id != VOLUME_ID_DISKLABEL)) {
 209                         rc = 3;
 210                         goto exit;
 211                 }
 212                 printf("%s\n", name);
 213                 break;
 214         case PRINT_UUID:
 215                 if (vid->uuid[0] == '\0' || vid->usage_id != VOLUME_ID_FILESYSTEM) {
 216                         rc = 4;
 217                         goto exit;
 218                 }
 219                 printf("%s\n", vid->uuid);
 220                 break;
 221         }
 222
 223 exit:
 224         if (vid != NULL)
 225                 volume_id_close(vid);
 226
 227         logging_close();
 228         return rc;
 229 }