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 <errno.h>
  31 #include <pwd.h>
  32 #include <grp.h>
  33 #include <getopt.h>
  34 #include <fcntl.h>
  35 #include <sys/ioctl.h>
  36
  37 #include "../../udev/udev.h"
  38 #include "lib/libvolume_id.h"
  39
  40 #define BLKGETSIZE64 _IOR(0x12,114,size_t)
  41
  42 static void log_fn(struct udev *udev, int priority,
  43                    const char *file, int line, const char *fn,
  44                    const char *format, va_list args)
  45 {
  46         vsyslog(priority, format, args);
  47 }
  48
  49 static void vid_log(int priority, const char *file, int line, const char *format, ...)
  50 {
  51         va_list args;
  52
  53         va_start(args, format);
  54         log_fn(NULL, priority, file, line, NULL, format, args);
  55         va_end(args);
  56         return;
  57 }
  58
  59 static void set_str(char *to, const char *from, size_t count)
  60 {
  61         size_t i, j, len;
  62
  63         /* strip trailing whitespace */
  64         len = strnlen(from, count);
  65         while (len && isspace(from[len-1]))
  66                 len--;
  67
  68         /* strip leading whitespace */
  69         i = 0;
  70         while (isspace(from[i]) && (i < len))
  71                 i++;
  72
  73         j = 0;
  74         while (i < len) {
  75                 /* substitute multiple whitespace */
  76                 if (isspace(from[i])) {
  77                         while (isspace(from[i]))
  78                                 i++;
  79                         to[j++] = '_';
  80                 }
  81                 /* skip chars */
  82                 if (from[i] == '/') {
  83                         i++;
  84                         continue;
  85                 }
  86                 to[j++] = from[i++];
  87         }
  88         to[j] = '\0';
  89 }
  90
  91 static int all_probers(volume_id_probe_fn_t probe_fn,
  92                        struct volume_id *id, uint64_t off, uint64_t size,
  93                        void *data)
  94 {
  95         const char *type;
  96
  97         if (probe_fn(id, off, size) == 0)
  98                 if (volume_id_get_type(id, &type))
  99                         printf("%s\n", type);
 100
 101         return 0;
 102 }
 103
 104 int main(int argc, char *argv[])
 105 {
 106         struct udev *udev;
 107         static const struct option options[] = {
 108                 { "label", 0, NULL, 'l' },
 109                 { "label-raw", 0, NULL, 'L' },
 110                 { "uuid", 0, NULL, 'u' },
 111                 { "type", 0, NULL, 't' },
 112                 { "export", 0, NULL, 'x' },
 113                 { "skip-raid", 0, NULL, 's' },
 114                 { "probe-all", 0, NULL, 'a' },
 115                 { "offset", 2, NULL, 'o' },
 116                 { "help", 0, NULL, 'h' },
 117                 {}
 118         };
 119
 120         enum print_type {
 121                 PRINT_EXPORT,
 122                 PRINT_TYPE,
 123                 PRINT_LABEL,
 124                 PRINT_UUID,
 125                 PRINT_LABEL_RAW,
 126         } print = PRINT_EXPORT;
 127
 128         struct volume_id *vid = NULL;
 129         char label_safe[256];
 130         char label_enc[256];
 131         char uuid_enc[256];
 132         uint64_t size;
 133         int skip_raid = 0;
 134         int probe_all = 0;
 135         uint64_t offset = 0;
 136         const char *node;
 137         int fd;
 138         const char *label, *uuid, *type, *type_version, *usage;
 139         int retval;
 140         int rc = 0;
 141
 142         udev = udev_new();
 143         if (udev == NULL)
 144                 goto exit;
 145         logging_init("vol_id");
 146         udev_set_log_fn(udev, log_fn);
 147
 148         /* hook in our debug into libvolume_id */
 149         volume_id_log_fn = vid_log;
 150
 151         while (1) {
 152                 int option;
 153
 154                 option = getopt_long(argc, argv, "lLutxsaoh", options, NULL);
 155                 if (option == -1)
 156                         break;
 157
 158                 switch (option) {
 159                 case 'l':
 160                         print = PRINT_LABEL;
 161                         break;
 162                 case 'L':
 163                         print = PRINT_LABEL_RAW;
 164                         break;
 165                 case 'u':
 166                         print = PRINT_UUID;
 167                         break;
 168                 case 't':
 169                         print = PRINT_TYPE;
 170                         break;
 171                 case 'x':
 172                         print = PRINT_EXPORT;
 173                         break;
 174                 case 's':
 175                         skip_raid = 1;
 176                         break;
 177                 case 'a':
 178                         probe_all = 1;
 179                         break;
 180                 case 'o':
 181                         if (optarg[0] != '\0')
 182                                 offset = strtoull(optarg, NULL, 0);
 183                         break;
 184                 case 'h':
 185                         printf("Usage: vol_id [options] <device>\n"
 186                             " --export        export key/value pairs\n"
 187                             " --type          filesystem type\n"
 188                             " --label         filesystem label\n"
 189                             " --label-raw     raw label\n"
 190                             " --uuid          filesystem uuid\n"
 191                             " --skip-raid     don't probe for raid\n"
 192                             " --probe-all     find possibly conflicting signatures\n"
 193                             " --offset        skip given number of bytes of input\n"
 194                             " --help\n\n");
 195                         goto exit;
 196                 default:
 197                         retval = 1;
 198                         goto exit;
 199                 }
 200         }
 201
 202         node = argv[optind];
 203         if (!node) {
 204                 err(udev, "no device\n");
 205                 fprintf(stderr, "no device\n");
 206                 rc = 1;
 207                 goto exit;
 208         }
 209
 210         fd = open(node, O_RDONLY);
 211         if (fd < 0) {
 212                 fprintf(stderr, "%s: error opening volume\n", node);
 213                 rc = 2;
 214                 goto exit;
 215         }
 216
 217         vid = volume_id_open_fd(fd);
 218         if (vid == NULL) {
 219                 rc = 2;
 220                 goto exit;
 221         }
 222
 223         if (ioctl(fd, BLKGETSIZE64, &size) != 0)
 224                 size = 0;
 225         dbg(udev, "BLKGETSIZE64=%llu\n", (unsigned long long)size);
 226
 227         /* try to drop all privileges before reading disk content */
 228         if (getuid() == 0) {
 229                 struct passwd *pw;
 230
 231                 pw = getpwnam("nobody");
 232                 if (pw != NULL && pw->pw_uid > 0 && pw->pw_gid > 0) {
 233                         if (setgroups(0, NULL) != 0 ||
 234                             setgid(pw->pw_gid) != 0 ||
 235                             setuid(pw->pw_uid) != 0)
 236                                 info(udev, "unable to drop privileges: %s\n\n", strerror(errno));
 237                 }
 238         }
 239
 240         if (probe_all) {
 241                 volume_id_all_probers(all_probers, vid, offset, size, NULL);
 242                 goto exit;
 243         }
 244
 245         if (skip_raid)
 246                 retval = volume_id_probe_filesystem(vid, offset, size);
 247         else
 248                 retval = volume_id_probe_all(vid, offset, size);
 249         if (retval != 0) {
 250                 fprintf(stderr, "%s: unknown volume type\n", node);
 251                 rc = 4;
 252                 goto exit;
 253         }
 254
 255         if (!volume_id_get_label(vid, &label) ||
 256             !volume_id_get_usage(vid, &usage) ||
 257             !volume_id_get_type(vid, &type) ||
 258             !volume_id_get_type_version(vid, &type_version) ||
 259             !volume_id_get_uuid(vid, &uuid)) {
 260                 rc = 4;
 261                 goto exit;
 262         }
 263
 264         set_str(label_safe, label, sizeof(label_safe));
 265         replace_chars(label_safe, ALLOWED_CHARS_INPUT);
 266
 267         volume_id_encode_string(label, label_enc, sizeof(label_enc));
 268         volume_id_encode_string(uuid, uuid_enc, sizeof(uuid_enc));
 269
 270         switch (print) {
 271         case PRINT_EXPORT:
 272                 printf("ID_FS_USAGE=%s\n", usage);
 273                 printf("ID_FS_TYPE=%s\n", type);
 274                 printf("ID_FS_VERSION=%s\n", type_version);
 275                 printf("ID_FS_UUID=%s\n", uuid);
 276                 printf("ID_FS_UUID_ENC=%s\n", uuid_enc);
 277                 printf("ID_FS_LABEL=%s\n", label);
 278                 printf("ID_FS_LABEL_ENC=%s\n", label_enc);
 279                 printf("ID_FS_LABEL_SAFE=%s\n", label_safe);
 280                 break;
 281         case PRINT_TYPE:
 282                 printf("%s\n", type);
 283                 break;
 284         case PRINT_LABEL:
 285                 if (label_safe[0] == '\0' || strcmp(usage, "raid") == 0) {
 286                         rc = 3;
 287                         goto exit;
 288                 }
 289                 printf("%s\n", label_safe);
 290                 break;
 291         case PRINT_UUID:
 292                 if (uuid_enc[0] == '\0' || strcmp(usage, "raid") == 0) {
 293                         rc = 4;
 294                         goto exit;
 295                 }
 296                 printf("%s\n", uuid_enc);
 297                 break;
 298         case PRINT_LABEL_RAW:
 299                 if (label[0] == '\0' || strcmp(usage, "raid") == 0) {
 300                         rc = 3;
 301                         goto exit;
 302                 }
 303                 printf("%s\n", label);
 304                 break;
 305         }
 306
 307 exit:
 308         if (vid != NULL)
 309                 volume_id_close(vid);
 310         udev_unref(udev);
 311         logging_close();
 312         return rc;
 313 }