lib/blkid/probe.c

   1 /*
   2  * probe.c - identify a block device by its contents, and return a dev
   3  *           struct with the details
   4  *
   5  * Copyright (C) 1999 by Andries Brouwer
   6  * Copyright (C) 1999, 2000, 2003 by Theodore Ts'o
   7  * Copyright (C) 2001 by Andreas Dilger
   8  * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
   9  *
  10  * %Begin-Header%
  11  * This file may be redistributed under the terms of the
  12  * GNU Lesser General Public License.
  13  * %End-Header%
  14  */
  15
  16 #include <stdio.h>
  17 #include <string.h>
  18 #include <stdlib.h>
  19 #include <unistd.h>
  20 #include <fcntl.h>
  21 #include <sys/types.h>
  22 #ifdef HAVE_SYS_STAT_H
  23 #include <sys/stat.h>
  24 #endif
  25 #ifdef HAVE_SYS_MKDEV_H
  26 #include <sys/mkdev.h>
  27 #endif
  28 #include <sys/utsname.h>
  29 #ifdef HAVE_ERRNO_H
  30 #include <errno.h>
  31 #endif
  32 #include "blkidP.h"
  33 #include "uuid/uuid.h"
  34 #include "probe.h"
  35
  36 static int figure_label_len(const unsigned char *label, int len)
  37 {
  38         const unsigned char *end = label + len - 1;
  39
  40         while ((*end == ' ' || *end == 0) && end >= label)
  41                 --end;
  42         if (end >= label) {
  43                 label = label;
  44                 return end - label + 1;
  45         }
  46         return 0;
  47 }
  48
  49 static unsigned char *get_buffer(struct blkid_probe *pr,
  50                           blkid_loff_t off, size_t len)
  51 {
  52         ssize_t         ret_read;
  53         unsigned char   *newbuf;
  54
  55         if (off + len <= SB_BUFFER_SIZE) {
  56                 if (!pr->sbbuf) {
  57                         pr->sbbuf = malloc(SB_BUFFER_SIZE);
  58                         if (!pr->sbbuf)
  59                                 return NULL;
  60                         if (lseek(pr->fd, 0, SEEK_SET) < 0)
  61                                 return NULL;
  62                         ret_read = read(pr->fd, pr->sbbuf, SB_BUFFER_SIZE);
  63                         if (ret_read < 0)
  64                                 ret_read = 0;
  65                         pr->sb_valid = ret_read;
  66                 }
  67                 if (off+len > pr->sb_valid)
  68                         return NULL;
  69                 return pr->sbbuf + off;
  70         } else {
  71                 if (len > pr->buf_max) {
  72                         newbuf = realloc(pr->buf, len);
  73                         if (newbuf == NULL)
  74                                 return NULL;
  75                         pr->buf = newbuf;
  76                         pr->buf_max = len;
  77                 }
  78                 if (blkid_llseek(pr->fd, off, SEEK_SET) < 0)
  79                         return NULL;
  80                 ret_read = read(pr->fd, pr->buf, len);
  81                 if (ret_read != (ssize_t) len)
  82                         return NULL;
  83                 return pr->buf;
  84         }
  85 }
  86
  87
  88 /*
  89  * This is a special case code to check for an MDRAID device.  We do
  90  * this special since it requires checking for a superblock at the end
  91  * of the device.
  92  */
  93 static int check_mdraid(int fd, unsigned char *ret_uuid)
  94 {
  95         struct mdp_superblock_s *md;
  96         blkid_loff_t            offset;
  97         char                    buf[4096];
  98
  99         if (fd < 0)
 100                 return -BLKID_ERR_PARAM;
 101
 102         offset = (blkid_get_dev_size(fd) & ~((blkid_loff_t)65535)) - 65536;
 103
 104         if (blkid_llseek(fd, offset, 0) < 0 ||
 105             read(fd, buf, 4096) != 4096)
 106                 return -BLKID_ERR_IO;
 107
 108         /* Check for magic number */
 109         if (memcmp("\251+N\374", buf, 4) && memcmp("\374N+\251", buf, 4))
 110                 return -BLKID_ERR_PARAM;
 111
 112         if (!ret_uuid)
 113                 return 0;
 114         *ret_uuid = 0;
 115
 116         /* The MD UUID is not contiguous in the superblock, make it so */
 117         md = (struct mdp_superblock_s *)buf;
 118         if (md->set_uuid0 || md->set_uuid1 || md->set_uuid2 || md->set_uuid3) {
 119                 memcpy(ret_uuid, &md->set_uuid0, 4);
 120                 memcpy(ret_uuid + 4, &md->set_uuid1, 12);
 121         }
 122         return 0;
 123 }
 124
 125 static void set_uuid(blkid_dev dev, uuid_t uuid, char *tag)
 126 {
 127         char    str[37];
 128
 129         if (!uuid_is_null(uuid)) {
 130                 uuid_unparse(uuid, str);
 131                 blkid_set_tag(dev, tag ? tag : "UUID", str, sizeof(str));
 132         }
 133 }
 134
 135 static void get_ext2_info(blkid_dev dev, struct blkid_magic *id,
 136                           unsigned char *buf)
 137 {
 138         struct ext2_super_block *es = (struct ext2_super_block *) buf;
 139         const char *label = 0;
 140
 141         DBG(DEBUG_PROBE, printf("ext2_sb.compat = %08X:%08X:%08X\n",
 142                    blkid_le32(es->s_feature_compat),
 143                    blkid_le32(es->s_feature_incompat),
 144                    blkid_le32(es->s_feature_ro_compat)));
 145
 146         if (strlen(es->s_volume_name))
 147                 label = es->s_volume_name;
 148         blkid_set_tag(dev, "LABEL", label, sizeof(es->s_volume_name));
 149
 150         set_uuid(dev, es->s_uuid, 0);
 151
 152         if ((es->s_feature_compat & EXT3_FEATURE_COMPAT_HAS_JOURNAL) &&
 153             !uuid_is_null(es->s_journal_uuid))
 154                 set_uuid(dev, es->s_journal_uuid, "EXT_JOURNAL");
 155
 156         if (strcmp(id->bim_type, "ext2") &&
 157             ((blkid_le32(es->s_feature_incompat) &
 158               EXT2_FEATURE_INCOMPAT_UNSUPPORTED) == 0))
 159                 blkid_set_tag(dev, "SEC_TYPE", "ext2", sizeof("ext2"));
 160 }
 161
 162 /*
 163  * Check to see if a filesystem is in /proc/filesystems.
 164  * Returns 1 if found, 0 if not
 165  */
 166 int fs_proc_check(const char *fs_name)
 167 {
 168         FILE    *f;
 169         char    buf[80], *cp, *t;
 170
 171         f = fopen("/proc/filesystems", "r");
 172         if (!f)
 173                 return (0);
 174         while (!feof(f)) {
 175                 if (!fgets(buf, sizeof(buf), f))
 176                         break;
 177                 cp = buf;
 178                 if (!isspace(*cp)) {
 179                         while (*cp && !isspace(*cp))
 180                                 cp++;
 181                 }
 182                 while (*cp && isspace(*cp))
 183                         cp++;
 184                 if ((t = strchr(cp, '\n')) != NULL)
 185                         *t = 0;
 186                 if ((t = strchr(cp, '\t')) != NULL)
 187                         *t = 0;
 188                 if ((t = strchr(cp, ' ')) != NULL)
 189                         *t = 0;
 190                 if (!strcmp(fs_name, cp)) {
 191                         fclose(f);
 192                         return (1);
 193                 }
 194         }
 195         fclose(f);
 196         return (0);
 197 }
 198
 199 /*
 200  * Check to see if a filesystem is available as a module
 201  * Returns 1 if found, 0 if not
 202  */
 203 int check_for_modules(const char *fs_name)
 204 {
 205         struct utsname  uts;
 206         FILE            *f;
 207         char            buf[1024], *cp, *t;
 208         int             i;
 209
 210         if (uname(&uts))
 211                 return (0);
 212         snprintf(buf, sizeof(buf), "/lib/modules/%s/modules.dep", uts.release);
 213
 214         f = fopen(buf, "r");
 215         if (!f)
 216                 return (0);
 217         while (!feof(f)) {
 218                 if (!fgets(buf, sizeof(buf), f))
 219                         break;
 220                 if ((cp = strchr(buf, ':')) != NULL)
 221                         *cp = 0;
 222                 else
 223                         continue;
 224                 if ((cp = strrchr(buf, '/')) != NULL)
 225                         cp++;
 226                 i = strlen(cp);
 227                 if (i > 3) {
 228                         t = cp + i - 3;
 229                         if (!strcmp(t, ".ko"))
 230                                 *t = 0;
 231                 }
 232                 if (!strcmp(cp, fs_name))
 233                         return (1);
 234         }
 235         fclose(f);
 236         return (0);
 237 }
 238
 239 static int system_supports_ext4()
 240 {
 241         static time_t   last_check = 0;
 242         static int      ret = -1;
 243         time_t          now = time(0);
 244
 245         if (ret != -1 || (last_check - now) < 5)
 246                 return ret;
 247         last_check = now;
 248         ret = (fs_proc_check("ext4") || check_for_modules("ext4"));
 249         return ret;
 250 }
 251
 252 static int system_supports_ext4dev()
 253 {
 254         static time_t   last_check = 0;
 255         static int      ret = -1;
 256         time_t          now = time(0);
 257
 258         if (ret != -1 || (last_check - now) < 5)
 259                 return ret;
 260         last_check = now;
 261         ret = (fs_proc_check("ext4dev") || check_for_modules("ext4dev"));
 262         return ret;
 263 }
 264
 265 static int probe_ext4dev(struct blkid_probe *probe,
 266                          struct blkid_magic *id,
 267                          unsigned char *buf)
 268 {
 269         struct ext2_super_block *es;
 270         es = (struct ext2_super_block *)buf;
 271
 272         /* Distinguish from jbd */
 273         if (blkid_le32(es->s_feature_incompat) &
 274             EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)
 275                 return -BLKID_ERR_PARAM;
 276
 277         /* ext4dev requires a journal */
 278         if (!(blkid_le32(es->s_feature_compat) &
 279               EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 280                 return -BLKID_ERR_PARAM;
 281
 282         /*
 283          * If the filesystem is marked as OK for use by in-development
 284          * filesystem code, but ext4dev is not supported, and ext4 is,
 285          * then don't call ourselves ext4dev, since we should be
 286          * detected as ext4 in that case.
 287          *
 288          * If the filesystem is marked as in use by production
 289          * filesystem, then it can only be used by ext4 and NOT by
 290          * ext4dev, so always disclaim we are ext4dev in that case.
 291          */
 292         if (blkid_le32(es->s_flags) & EXT2_FLAGS_TEST_FILESYS) {
 293                 if (!system_supports_ext4dev() && system_supports_ext4())
 294                         return -BLKID_ERR_PARAM;
 295         } else
 296                 return -BLKID_ERR_PARAM;
 297
 298         get_ext2_info(probe->dev, id, buf);
 299         return 0;
 300 }
 301
 302 static int probe_ext4(struct blkid_probe *probe, struct blkid_magic *id,
 303                       unsigned char *buf)
 304 {
 305         struct ext2_super_block *es;
 306         es = (struct ext2_super_block *)buf;
 307
 308         /* Distinguish from jbd */
 309         if (blkid_le32(es->s_feature_incompat) &
 310             EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)
 311                 return -BLKID_ERR_PARAM;
 312
 313         /* ext4 requires journal */
 314         if (!(blkid_le32(es->s_feature_compat) &
 315               EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 316                 return -BLKID_ERR_PARAM;
 317
 318         /* Ext4 has at least one feature which ext3 doesn't understand */
 319         if (!(blkid_le32(es->s_feature_ro_compat) &
 320               EXT3_FEATURE_RO_COMPAT_UNSUPPORTED) &&
 321             !(blkid_le32(es->s_feature_incompat) &
 322               EXT3_FEATURE_INCOMPAT_UNSUPPORTED))
 323                 return -BLKID_ERR_PARAM;
 324
 325         /*
 326          * If the filesystem is a OK for use by in-development
 327          * filesystem code, and ext4dev is supported or ext4 is not
 328          * supported, then don't call ourselves ext4, so we can redo
 329          * the detection and mark the filesystem as ext4dev.
 330          *
 331          * If the filesystem is marked as in use by production
 332          * filesystem, then it can only be used by ext4 and NOT by
 333          * ext4dev.
 334          */
 335         if (blkid_le32(es->s_flags) & EXT2_FLAGS_TEST_FILESYS) {
 336                 if (system_supports_ext4dev() || !system_supports_ext4())
 337                         return -BLKID_ERR_PARAM;
 338         }
 339         get_ext2_info(probe->dev, id, buf);
 340         return 0;
 341 }
 342
 343 static int probe_ext3(struct blkid_probe *probe, struct blkid_magic *id,
 344                       unsigned char *buf)
 345 {
 346         struct ext2_super_block *es;
 347         es = (struct ext2_super_block *)buf;
 348
 349         /* Distinguish from ext4dev */
 350         if (blkid_le32(es->s_flags) & EXT2_FLAGS_TEST_FILESYS)
 351                 return -BLKID_ERR_PARAM;
 352
 353         /* ext3 requires journal */
 354         if (!(blkid_le32(es->s_feature_compat) &
 355               EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 356                 return -BLKID_ERR_PARAM;
 357
 358         /* Any features which ext3 doesn't understand */
 359         if ((blkid_le32(es->s_feature_ro_compat) &
 360              EXT3_FEATURE_RO_COMPAT_UNSUPPORTED) ||
 361             (blkid_le32(es->s_feature_incompat) &
 362              EXT3_FEATURE_INCOMPAT_UNSUPPORTED))
 363                 return -BLKID_ERR_PARAM;
 364
 365         get_ext2_info(probe->dev, id, buf);
 366         return 0;
 367 }
 368
 369 static int probe_ext2(struct blkid_probe *probe, struct blkid_magic *id,
 370                       unsigned char *buf)
 371 {
 372         struct ext2_super_block *es;
 373
 374         es = (struct ext2_super_block *)buf;
 375
 376         /* Distinguish between ext3 and ext2 */
 377         if ((blkid_le32(es->s_feature_compat) &
 378               EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 379                 return -BLKID_ERR_PARAM;
 380
 381         /* Any features which ext2 doesn't understand */
 382         if ((blkid_le32(es->s_feature_ro_compat) &
 383              EXT2_FEATURE_RO_COMPAT_UNSUPPORTED) ||
 384             (blkid_le32(es->s_feature_incompat) &
 385              EXT2_FEATURE_INCOMPAT_UNSUPPORTED))
 386                 return -BLKID_ERR_PARAM;
 387
 388         get_ext2_info(probe->dev, id, buf);
 389         return 0;
 390 }
 391
 392 static int probe_jbd(struct blkid_probe *probe, struct blkid_magic *id,
 393                      unsigned char *buf)
 394 {
 395         struct ext2_super_block *es = (struct ext2_super_block *) buf;
 396
 397         if (!(blkid_le32(es->s_feature_incompat) &
 398               EXT3_FEATURE_INCOMPAT_JOURNAL_DEV))
 399                 return -BLKID_ERR_PARAM;
 400
 401         get_ext2_info(probe->dev, id, buf);
 402
 403         return 0;
 404 }
 405
 406 #define FAT_ATTR_VOLUME_ID              0x08
 407 #define FAT_ATTR_DIR                    0x10
 408 #define FAT_ATTR_LONG_NAME              0x0f
 409 #define FAT_ATTR_MASK                   0x3f
 410 #define FAT_ENTRY_FREE                  0xe5
 411
 412 static char *no_name = "NO NAME    ";
 413
 414 static unsigned char *search_fat_label(struct vfat_dir_entry *dir, int count)
 415 {
 416         int i;
 417
 418         for (i = 0; i < count; i++) {
 419                 if (dir[i].name[0] == 0x00)
 420                         break;
 421
 422                 if ((dir[i].name[0] == FAT_ENTRY_FREE) ||
 423                     (dir[i].cluster_high != 0 || dir[i].cluster_low != 0) ||
 424                     ((dir[i].attr & FAT_ATTR_MASK) == FAT_ATTR_LONG_NAME))
 425                         continue;
 426
 427                 if ((dir[i].attr & (FAT_ATTR_VOLUME_ID | FAT_ATTR_DIR)) ==
 428                     FAT_ATTR_VOLUME_ID) {
 429                         return dir[i].name;
 430                 }
 431         }
 432         return 0;
 433 }
 434
 435 /* FAT label extraction from the root directory taken from Kay
 436  * Sievers's volume_id library */
 437 static int probe_fat(struct blkid_probe *probe,
 438                       struct blkid_magic *id __BLKID_ATTR((unused)),
 439                       unsigned char *buf)
 440 {
 441         struct vfat_super_block *vs = (struct vfat_super_block *) buf;
 442         struct msdos_super_block *ms = (struct msdos_super_block *) buf;
 443         struct vfat_dir_entry *dir;
 444         char serno[10];
 445         const unsigned char *label = 0, *vol_label = 0, *tmp;
 446         unsigned char   *vol_serno;
 447         int label_len = 0, maxloop = 100;
 448         __u16 sector_size, dir_entries, reserved;
 449         __u32 sect_count, fat_size, dir_size, cluster_count, fat_length;
 450         __u32 buf_size, start_data_sect, next, root_start, root_dir_entries;
 451
 452         /* sector size check */
 453         tmp = (unsigned char *)&ms->ms_sector_size;
 454         sector_size = tmp[0] + (tmp[1] << 8);
 455         if (sector_size != 0x200 && sector_size != 0x400 &&
 456             sector_size != 0x800 && sector_size != 0x1000)
 457                 return 1;
 458
 459         tmp = (unsigned char *)&ms->ms_dir_entries;
 460         dir_entries = tmp[0] + (tmp[1] << 8);
 461         reserved =  blkid_le16(ms->ms_reserved);
 462         tmp = (unsigned char *)&ms->ms_sectors;
 463         sect_count = tmp[0] + (tmp[1] << 8);
 464         if (sect_count == 0)
 465                 sect_count = blkid_le32(ms->ms_total_sect);
 466
 467         fat_length = blkid_le16(ms->ms_fat_length);
 468         if (fat_length == 0)
 469                 fat_length = blkid_le32(vs->vs_fat32_length);
 470
 471         fat_size = fat_length * ms->ms_fats;
 472         dir_size = ((dir_entries * sizeof(struct vfat_dir_entry)) +
 473                         (sector_size-1)) / sector_size;
 474
 475         cluster_count = sect_count - (reserved + fat_size + dir_size);
 476         if (ms->ms_cluster_size == 0)
 477                 return 1;
 478         cluster_count /= ms->ms_cluster_size;
 479
 480         if (cluster_count > FAT32_MAX)
 481                 return 1;
 482
 483         if (ms->ms_fat_length) {
 484                 /* the label may be an attribute in the root directory */
 485                 root_start = (reserved + fat_size) * sector_size;
 486                 root_dir_entries = vs->vs_dir_entries[0] +
 487                         (vs->vs_dir_entries[1] << 8);
 488
 489                 buf_size = root_dir_entries * sizeof(struct vfat_dir_entry);
 490                 dir = (struct vfat_dir_entry *) get_buffer(probe, root_start,
 491                                                            buf_size);
 492                 if (dir)
 493                         vol_label = search_fat_label(dir, root_dir_entries);
 494
 495                 if (!vol_label || !memcmp(vol_label, no_name, 11))
 496                         vol_label = ms->ms_label;
 497                 vol_serno = ms->ms_serno;
 498
 499                 blkid_set_tag(probe->dev, "SEC_TYPE", "msdos",
 500                               sizeof("msdos"));
 501         } else {
 502                 /* Search the FAT32 root dir for the label attribute */
 503                 buf_size = vs->vs_cluster_size * sector_size;
 504                 start_data_sect = reserved + fat_size;
 505
 506                 next = blkid_le32(vs->vs_root_cluster);
 507                 while (next && --maxloop) {
 508                         __u32 next_sect_off;
 509                         __u64 next_off, fat_entry_off;
 510                         int count;
 511
 512                         next_sect_off = (next - 2) * vs->vs_cluster_size;
 513                         next_off = (start_data_sect + next_sect_off) *
 514                                 sector_size;
 515
 516                         dir = (struct vfat_dir_entry *)
 517                                 get_buffer(probe, next_off, buf_size);
 518                         if (dir == NULL)
 519                                 break;
 520
 521                         count = buf_size / sizeof(struct vfat_dir_entry);
 522
 523                         vol_label = search_fat_label(dir, count);
 524                         if (vol_label)
 525                                 break;
 526
 527                         /* get FAT entry */
 528                         fat_entry_off = (reserved * sector_size) +
 529                                 (next * sizeof(__u32));
 530                         buf = get_buffer(probe, fat_entry_off, buf_size);
 531                         if (buf == NULL)
 532                                 break;
 533
 534                         /* set next cluster */
 535                         next = blkid_le32(*((__u32 *) buf) & 0x0fffffff);
 536                 }
 537
 538                 if (!vol_label || !memcmp(vol_label, no_name, 11))
 539                         vol_label = vs->vs_label;
 540                 vol_serno = vs->vs_serno;
 541         }
 542
 543         if (vol_label && memcmp(vol_label, no_name, 11)) {
 544                 if ((label_len = figure_label_len(vol_label, 11)))
 545                         label = vol_label;
 546         }
 547
 548         /* We can't just print them as %04X, because they are unaligned */
 549         sprintf(serno, "%02X%02X-%02X%02X", vol_serno[3], vol_serno[2],
 550                 vol_serno[1], vol_serno[0]);
 551
 552         blkid_set_tag(probe->dev, "LABEL", (const char *) label, label_len);
 553         blkid_set_tag(probe->dev, "UUID", serno, sizeof(serno)-1);
 554
 555         return 0;
 556 }
 557
 558 /*
 559  * The FAT filesystem could be without a magic string in superblock
 560  * (e.g. old floppies).  This heuristic for FAT detection is inspired
 561  * by http://vrfy.org/projects/volume_id/ and Linux kernel.
 562  * [7-Jul-2005, Karel Zak <kzak@redhat.com>]
 563  */
 564 static int probe_fat_nomagic(struct blkid_probe *probe,
 565                              struct blkid_magic *id __BLKID_ATTR((unused)),
 566                              unsigned char *buf)
 567 {
 568         struct vfat_super_block *vs;
 569
 570         vs = (struct vfat_super_block *)buf;
 571
 572         /* heads check */
 573         if (vs->vs_heads == 0)
 574                 return 1;
 575
 576         /* cluster size check*/
 577         if (vs->vs_cluster_size == 0 ||
 578             (vs->vs_cluster_size & (vs->vs_cluster_size-1)))
 579                 return 1;
 580
 581         /* media check */
 582         if (vs->vs_media < 0xf8 && vs->vs_media != 0xf0)
 583                 return 1;
 584
 585         /* fat counts(Linux kernel expects at least 1 FAT table) */
 586         if (!vs->vs_fats)
 587                 return 1;
 588
 589         return probe_fat(probe, id, buf);
 590 }
 591
 592 static int probe_ntfs(struct blkid_probe *probe,
 593                       struct blkid_magic *id __BLKID_ATTR((unused)),
 594                       unsigned char *buf)
 595 {
 596         struct ntfs_super_block *ns;
 597         struct master_file_table_record *mft;
 598         struct file_attribute *attr;
 599         char            uuid_str[17], label_str[129], *cp;
 600         int             bytes_per_sector, sectors_per_cluster;
 601         int             mft_record_size, attr_off, attr_len;
 602         unsigned int    i, attr_type, val_len;
 603         int             val_off;
 604         __u64           nr_clusters;
 605         blkid_loff_t off;
 606         unsigned char *buf_mft, *val;
 607
 608         ns = (struct ntfs_super_block *) buf;
 609
 610         bytes_per_sector = ns->bios_parameter_block[0] +
 611                 (ns->bios_parameter_block[1]  << 8);
 612         sectors_per_cluster = ns->bios_parameter_block[2];
 613
 614         if ((bytes_per_sector < 512) || (sectors_per_cluster == 0))
 615                 return 1;
 616
 617         if (ns->cluster_per_mft_record < 0)
 618                 mft_record_size = 1 << (0-ns->cluster_per_mft_record);
 619         else
 620                 mft_record_size = ns->cluster_per_mft_record *
 621                         sectors_per_cluster * bytes_per_sector;
 622         nr_clusters = blkid_le64(ns->number_of_sectors) / sectors_per_cluster;
 623
 624         if ((blkid_le64(ns->mft_cluster_location) > nr_clusters) ||
 625             (blkid_le64(ns->mft_mirror_cluster_location) > nr_clusters))
 626                 return 1;
 627
 628         off = blkid_le64(ns->mft_mirror_cluster_location) *
 629                 bytes_per_sector * sectors_per_cluster;
 630
 631         buf_mft = get_buffer(probe, off, mft_record_size);
 632         if (!buf_mft)
 633                 return 1;
 634
 635         if (memcmp(buf_mft, "FILE", 4))
 636                 return 1;
 637
 638         off = blkid_le64(ns->mft_cluster_location) * bytes_per_sector *
 639                 sectors_per_cluster;
 640
 641         buf_mft = get_buffer(probe, off, mft_record_size);
 642         if (!buf_mft)
 643                 return 1;
 644
 645         if (memcmp(buf_mft, "FILE", 4))
 646                 return 1;
 647
 648         off += MFT_RECORD_VOLUME * mft_record_size;
 649
 650         buf_mft = get_buffer(probe, off, mft_record_size);
 651         if (!buf_mft)
 652                 return 1;
 653
 654         if (memcmp(buf_mft, "FILE", 4))
 655                 return 1;
 656
 657         mft = (struct master_file_table_record *) buf_mft;
 658
 659         attr_off = blkid_le16(mft->attrs_offset);
 660         label_str[0] = 0;
 661
 662         while (1) {
 663                 attr = (struct file_attribute *) (buf_mft + attr_off);
 664                 attr_len = blkid_le16(attr->len);
 665                 attr_type = blkid_le32(attr->type);
 666                 val_off = blkid_le16(attr->value_offset);
 667                 val_len = blkid_le32(attr->value_len);
 668
 669                 attr_off += attr_len;
 670
 671                 if ((attr_off > mft_record_size) ||
 672                     (attr_len == 0))
 673                         break;
 674
 675                 if (attr_type == MFT_RECORD_ATTR_END)
 676                         break;
 677
 678                 if (attr_type == MFT_RECORD_ATTR_VOLUME_NAME) {
 679                         if (val_len > sizeof(label_str))
 680                                 val_len = sizeof(label_str)-1;
 681
 682                         for (i=0, cp=label_str; i < val_len; i+=2,cp++) {
 683                                 val = ((__u8 *) attr) + val_off + i;
 684                                 *cp = val[0];
 685                                 if (val[1])
 686                                         *cp = '?';
 687                         }
 688                         *cp = 0;
 689                 }
 690         }
 691
 692         sprintf(uuid_str, "%016llX", blkid_le64(ns->volume_serial));
 693         blkid_set_tag(probe->dev, "UUID", uuid_str, 0);
 694         if (label_str[0])
 695                 blkid_set_tag(probe->dev, "LABEL", label_str, 0);
 696         return 0;
 697 }
 698
 699
 700 static int probe_xfs(struct blkid_probe *probe,
 701                      struct blkid_magic *id __BLKID_ATTR((unused)),
 702                      unsigned char *buf)
 703 {
 704         struct xfs_super_block *xs;
 705         const char *label = 0;
 706
 707         xs = (struct xfs_super_block *)buf;
 708
 709         if (strlen(xs->xs_fname))
 710                 label = xs->xs_fname;
 711         blkid_set_tag(probe->dev, "LABEL", label, sizeof(xs->xs_fname));
 712         set_uuid(probe->dev, xs->xs_uuid, 0);
 713         return 0;
 714 }
 715
 716 static int probe_reiserfs(struct blkid_probe *probe,
 717                           struct blkid_magic *id, unsigned char *buf)
 718 {
 719         struct reiserfs_super_block *rs = (struct reiserfs_super_block *) buf;
 720         unsigned int blocksize;
 721         const char *label = 0;
 722
 723         blocksize = blkid_le16(rs->rs_blocksize);
 724
 725         /* The blocksize must be at least 1k */
 726         if ((blocksize >> 10) == 0)
 727                 return -BLKID_ERR_PARAM;
 728
 729         /* If the superblock is inside the journal, we have the wrong one */
 730         if (id->bim_kboff/(blocksize>>10) > blkid_le32(rs->rs_journal_block))
 731                 return -BLKID_ERR_BIG;
 732
 733         /* LABEL/UUID are only valid for later versions of Reiserfs v3.6. */
 734         if (id->bim_magic[6] == '2' || id->bim_magic[6] == '3') {
 735                 if (strlen(rs->rs_label))
 736                         label = rs->rs_label;
 737                 set_uuid(probe->dev, rs->rs_uuid, 0);
 738         }
 739         blkid_set_tag(probe->dev, "LABEL", label, sizeof(rs->rs_label));
 740
 741         return 0;
 742 }
 743
 744 static int probe_reiserfs4(struct blkid_probe *probe,
 745                            struct blkid_magic *id __BLKID_ATTR((unused)),
 746                            unsigned char *buf)
 747 {
 748         struct reiser4_super_block *rs4 = (struct reiser4_super_block *) buf;
 749         const unsigned char *label = 0;
 750
 751         if (strlen((char *) rs4->rs4_label))
 752                 label = rs4->rs4_label;
 753         set_uuid(probe->dev, rs4->rs4_uuid, 0);
 754         blkid_set_tag(probe->dev, "LABEL", (const char *) label,
 755                       sizeof(rs4->rs4_label));
 756
 757         return 0;
 758 }
 759
 760 static int probe_jfs(struct blkid_probe *probe,
 761                      struct blkid_magic *id __BLKID_ATTR((unused)),
 762                      unsigned char *buf)
 763 {
 764         struct jfs_super_block *js;
 765         const char *label = 0;
 766
 767         js = (struct jfs_super_block *)buf;
 768
 769         if (strlen((char *) js->js_label))
 770                 label = (char *) js->js_label;
 771         blkid_set_tag(probe->dev, "LABEL", label, sizeof(js->js_label));
 772         set_uuid(probe->dev, js->js_uuid, 0);
 773         return 0;
 774 }
 775
 776 static int probe_luks(struct blkid_probe *probe,
 777                        struct blkid_magic *id __BLKID_ATTR((unused)),
 778                        unsigned char *buf)
 779 {
 780         unsigned char uuid[40];
 781         /* 168 is the offset to the 40 character uuid:
 782          * http://luks.endorphin.org/LUKS-on-disk-format.pdf */
 783         strncpy(uuid, buf+168, 40);
 784         blkid_set_tag(probe->dev, "UUID", uuid, sizeof(uuid));
 785         return 0;
 786 }
 787
 788 static int probe_romfs(struct blkid_probe *probe,
 789                        struct blkid_magic *id __BLKID_ATTR((unused)),
 790                        unsigned char *buf)
 791 {
 792         struct romfs_super_block *ros;
 793         const char *label = 0;
 794
 795         ros = (struct romfs_super_block *)buf;
 796
 797         if (strlen((char *) ros->ros_volume))
 798                 label = (char *) ros->ros_volume;
 799         blkid_set_tag(probe->dev, "LABEL", label, 0);
 800         return 0;
 801 }
 802
 803 static int probe_cramfs(struct blkid_probe *probe,
 804                         struct blkid_magic *id __BLKID_ATTR((unused)),
 805                         unsigned char *buf)
 806 {
 807         struct cramfs_super_block *csb;
 808         const char *label = 0;
 809
 810         csb = (struct cramfs_super_block *)buf;
 811
 812         if (strlen((char *) csb->name))
 813                 label = (char *) csb->name;
 814         blkid_set_tag(probe->dev, "LABEL", label, 0);
 815         return 0;
 816 }
 817
 818 static int probe_swap0(struct blkid_probe *probe,
 819                        struct blkid_magic *id __BLKID_ATTR((unused)),
 820                        unsigned char *buf __BLKID_ATTR((unused)))
 821 {
 822         blkid_set_tag(probe->dev, "UUID", 0, 0);
 823         blkid_set_tag(probe->dev, "LABEL", 0, 0);
 824         return 0;
 825 }
 826
 827 static int probe_swap1(struct blkid_probe *probe,
 828                        struct blkid_magic *id __BLKID_ATTR((unused)),
 829                        unsigned char *buf __BLKID_ATTR((unused)))
 830 {
 831         struct swap_id_block *sws;
 832
 833         probe_swap0(probe, id, buf);
 834         /*
 835          * Version 1 swap headers are always located at offset of 1024
 836          * bytes, although the swap signature itself is located at the
 837          * end of the page (which may vary depending on hardware
 838          * pagesize).
 839          */
 840         sws = (struct swap_id_block *) get_buffer(probe, 1024, 1024);
 841         if (!sws)
 842                 return 1;
 843
 844         /* arbitrary sanity check.. is there any garbage down there? */
 845         if (sws->sws_pad[32] == 0 && sws->sws_pad[33] == 0)  {
 846                 if (sws->sws_volume[0])
 847                         blkid_set_tag(probe->dev, "LABEL", sws->sws_volume,
 848                                       sizeof(sws->sws_volume));
 849                 if (sws->sws_uuid[0])
 850                         set_uuid(probe->dev, sws->sws_uuid, 0);
 851         }
 852         return 0;
 853 }
 854
 855 static int probe_iso9660(struct blkid_probe *probe,
 856                          struct blkid_magic *id __BLKID_ATTR((unused)),
 857                          unsigned char *buf)
 858 {
 859         struct iso_volume_descriptor *iso;
 860         const unsigned char *label;
 861
 862         iso = (struct iso_volume_descriptor *) buf;
 863         label = iso->volume_id;
 864
 865         blkid_set_tag(probe->dev, "LABEL", (const char *) label,
 866                       figure_label_len(label, 32));
 867         return 0;
 868 }
 869
 870
 871 static const char
 872 *udf_magic[] = { "BEA01", "BOOT2", "CD001", "CDW02", "NSR02",
 873                  "NSR03", "TEA01", 0 };
 874
 875 static int probe_udf(struct blkid_probe *probe,
 876                      struct blkid_magic *id __BLKID_ATTR((unused)),
 877                      unsigned char *buf __BLKID_ATTR((unused)))
 878 {
 879         int j, bs;
 880         struct iso_volume_descriptor *isosb;
 881         const char ** m;
 882
 883         /* determine the block size by scanning in 2K increments
 884            (block sizes larger than 2K will be null padded) */
 885         for (bs = 1; bs < 16; bs++) {
 886                 isosb = (struct iso_volume_descriptor *)
 887                         get_buffer(probe, bs*2048+32768, sizeof(isosb));
 888                 if (!isosb)
 889                         return 1;
 890                 if (isosb->vd_id[0])
 891                         break;
 892         }
 893
 894         /* Scan up to another 64 blocks looking for additional VSD's */
 895         for (j = 1; j < 64; j++) {
 896                 if (j > 1) {
 897                         isosb = (struct iso_volume_descriptor *)
 898                                 get_buffer(probe, j*bs*2048+32768,
 899                                            sizeof(isosb));
 900                         if (!isosb)
 901                                 return 1;
 902                 }
 903                 /* If we find NSR0x then call it udf:
 904                    NSR01 for UDF 1.00
 905                    NSR02 for UDF 1.50
 906                    NSR03 for UDF 2.00 */
 907                 if (!memcmp(isosb->vd_id, "NSR0", 4))
 908                         return probe_iso9660(probe, id, buf);
 909                 for (m = udf_magic; *m; m++)
 910                         if (!memcmp(*m, isosb->vd_id, 5))
 911                                 break;
 912                 if (*m == 0)
 913                         return 1;
 914         }
 915         return 1;
 916 }
 917
 918 static int probe_ocfs(struct blkid_probe *probe,
 919                       struct blkid_magic *id __BLKID_ATTR((unused)),
 920                       unsigned char *buf)
 921 {
 922         struct ocfs_volume_header ovh;
 923         struct ocfs_volume_label ovl;
 924         __u32 major;
 925
 926         memcpy(&ovh, buf, sizeof(ovh));
 927         memcpy(&ovl, buf+512, sizeof(ovl));
 928
 929         major = ocfsmajor(ovh);
 930         if (major == 1)
 931                 blkid_set_tag(probe->dev,"SEC_TYPE","ocfs1",sizeof("ocfs1"));
 932         else if (major >= 9)
 933                 blkid_set_tag(probe->dev,"SEC_TYPE","ntocfs",sizeof("ntocfs"));
 934
 935         blkid_set_tag(probe->dev, "LABEL", ovl.label, ocfslabellen(ovl));
 936         blkid_set_tag(probe->dev, "MOUNT", ovh.mount, ocfsmountlen(ovh));
 937         set_uuid(probe->dev, ovl.vol_id, 0);
 938         return 0;
 939 }
 940
 941 static int probe_ocfs2(struct blkid_probe *probe,
 942                        struct blkid_magic *id __BLKID_ATTR((unused)),
 943                        unsigned char *buf)
 944 {
 945         struct ocfs2_super_block *osb;
 946
 947         osb = (struct ocfs2_super_block *)buf;
 948
 949         blkid_set_tag(probe->dev, "LABEL", osb->s_label, sizeof(osb->s_label));
 950         set_uuid(probe->dev, osb->s_uuid, 0);
 951         return 0;
 952 }
 953
 954 static int probe_oracleasm(struct blkid_probe *probe,
 955                            struct blkid_magic *id __BLKID_ATTR((unused)),
 956                            unsigned char *buf)
 957 {
 958         struct oracle_asm_disk_label *dl;
 959
 960         dl = (struct oracle_asm_disk_label *)buf;
 961
 962         blkid_set_tag(probe->dev, "LABEL", dl->dl_id, sizeof(dl->dl_id));
 963         return 0;
 964 }
 965
 966 static int probe_gfs(struct blkid_probe *probe,
 967                      struct blkid_magic *id __BLKID_ATTR((unused)),
 968                      unsigned char *buf)
 969 {
 970         struct gfs2_sb *sbd;
 971         const char *label = 0;
 972
 973         sbd = (struct gfs2_sb *)buf;
 974
 975         if (blkid_be32(sbd->sb_fs_format) == GFS_FORMAT_FS &&
 976             blkid_be32(sbd->sb_multihost_format) == GFS_FORMAT_MULTI)
 977         {
 978                 blkid_set_tag(probe->dev, "UUID", 0, 0);
 979
 980                 if (strlen(sbd->sb_locktable))
 981                         label = sbd->sb_locktable;
 982                 blkid_set_tag(probe->dev, "LABEL", label, sizeof(sbd->sb_locktable));
 983                 return 0;
 984         }
 985         return 1;
 986 }
 987
 988 static int probe_gfs2(struct blkid_probe *probe,
 989                      struct blkid_magic *id __BLKID_ATTR((unused)),
 990                      unsigned char *buf)
 991 {
 992         struct gfs2_sb *sbd;
 993         const char *label = 0;
 994
 995         sbd = (struct gfs2_sb *)buf;
 996
 997         if (blkid_be32(sbd->sb_fs_format) == GFS2_FORMAT_FS &&
 998             blkid_be32(sbd->sb_multihost_format) == GFS2_FORMAT_MULTI)
 999         {
1000                 blkid_set_tag(probe->dev, "UUID", 0, 0);
1001
1002                 if (strlen(sbd->sb_locktable))
1003                         label = sbd->sb_locktable;
1004                 blkid_set_tag(probe->dev, "LABEL", label, sizeof(sbd->sb_locktable));
1005                 return 0;
1006         }
1007         return 1;
1008 }
1009
1010 static int probe_hfsplus(struct blkid_probe *probe,
1011                          struct blkid_magic *id __BLKID_ATTR((unused)),
1012                          unsigned char *buf)
1013 {
1014         struct hfs_mdb *sbd = (struct hfs_mdb *)buf;
1015
1016         /* Check for a HFS+ volume embedded in a HFS volume */
1017         if (memcmp(sbd->embed_sig, "H+", 2) == 0)
1018                 return 0;
1019
1020         return 1;
1021 }
1022
1023 /*
1024  * BLKID_BLK_OFFS is at least as large as the highest bim_kboff defined
1025  * in the type_array table below + bim_kbalign.
1026  *
1027  * When probing for a lot of magics, we handle everything in 1kB buffers so
1028  * that we don't have to worry about reading each combination of block sizes.
1029  */
1030 #define BLKID_BLK_OFFS  64      /* currently reiserfs */
1031
1032 /*
1033  * Various filesystem magics that we can check for.  Note that kboff and
1034  * sboff are in kilobytes and bytes respectively.  All magics are in
1035  * byte strings so we don't worry about endian issues.
1036  */
1037 static struct blkid_magic type_array[] = {
1038 /*  type     kboff   sboff len  magic                   probe */
1039   { "oracleasm", 0,     32,  8, "ORCLDISK",             probe_oracleasm },
1040   { "ntfs",      0,      3,  8, "NTFS    ",             probe_ntfs },
1041   { "jbd",       1,   0x38,  2, "\123\357",             probe_jbd },
1042   { "ext4dev",   1,   0x38,  2, "\123\357",             probe_ext4dev },
1043   { "ext4",      1,   0x38,  2, "\123\357",             probe_ext4 },
1044   { "ext3",      1,   0x38,  2, "\123\357",             probe_ext3 },
1045   { "ext2",      1,   0x38,  2, "\123\357",             probe_ext2 },
1046   { "reiserfs",  8,   0x34,  8, "ReIsErFs",             probe_reiserfs },
1047   { "reiserfs", 64,   0x34,  9, "ReIsEr2Fs",            probe_reiserfs },
1048   { "reiserfs", 64,   0x34,  9, "ReIsEr3Fs",            probe_reiserfs },
1049   { "reiserfs", 64,   0x34,  8, "ReIsErFs",             probe_reiserfs },
1050   { "reiserfs",  8,     20,  8, "ReIsErFs",             probe_reiserfs },
1051   { "reiser4",  64,      0,  7, "ReIsEr4",              probe_reiserfs4 },
1052   { "gfs2",     64,      0,  4, "\x01\x16\x19\x70",     probe_gfs2 },
1053   { "gfs",      64,      0,  4, "\x01\x16\x19\x70",     probe_gfs },
1054   { "vfat",      0,   0x52,  5, "MSWIN",                probe_fat },
1055   { "vfat",      0,   0x52,  8, "FAT32   ",             probe_fat },
1056   { "vfat",      0,   0x36,  5, "MSDOS",                probe_fat },
1057   { "vfat",      0,   0x36,  8, "FAT16   ",             probe_fat },
1058   { "vfat",      0,   0x36,  8, "FAT12   ",             probe_fat },
1059   { "vfat",      0,      0,  1, "\353",                 probe_fat_nomagic },
1060   { "vfat",      0,      0,  1, "\351",                 probe_fat_nomagic },
1061   { "vfat",      0,  0x1fe,  2, "\125\252",             probe_fat_nomagic },
1062   { "minix",     1,   0x10,  2, "\177\023",             0 },
1063   { "minix",     1,   0x10,  2, "\217\023",             0 },
1064   { "minix",     1,   0x10,  2, "\150\044",             0 },
1065   { "minix",     1,   0x10,  2, "\170\044",             0 },
1066   { "vxfs",      1,      0,  4, "\365\374\001\245",     0 },
1067   { "xfs",       0,      0,  4, "XFSB",                 probe_xfs },
1068   { "romfs",     0,      0,  8, "-rom1fs-",             probe_romfs },
1069   { "bfs",       0,      0,  4, "\316\372\173\033",     0 },
1070   { "cramfs",    0,      0,  4, "E=\315\050",           probe_cramfs },
1071   { "qnx4",      0,      4,  6, "QNX4FS",               0 },
1072   { "udf",      32,      1,  5, "BEA01",                probe_udf },
1073   { "udf",      32,      1,  5, "BOOT2",                probe_udf },
1074   { "udf",      32,      1,  5, "CD001",                probe_udf },
1075   { "udf",      32,      1,  5, "CDW02",                probe_udf },
1076   { "udf",      32,      1,  5, "NSR02",                probe_udf },
1077   { "udf",      32,      1,  5, "NSR03",                probe_udf },
1078   { "udf",      32,      1,  5, "TEA01",                probe_udf },
1079   { "iso9660",  32,      1,  5, "CD001",                probe_iso9660 },
1080   { "iso9660",  32,      9,  5, "CDROM",                probe_iso9660 },
1081   { "jfs",      32,      0,  4, "JFS1",                 probe_jfs },
1082   { "hfsplus",   1,      0,  2, "BD",                   probe_hfsplus },
1083   { "hfsplus",   1,      0,  2, "H+",                   0 },
1084   { "hfs",       1,      0,  2, "BD",                   0 },
1085   { "ufs",       8,  0x55c,  4, "T\031\001\000",        0 },
1086   { "hpfs",      8,      0,  4, "I\350\225\371",        0 },
1087   { "sysv",      0,  0x3f8,  4, "\020~\030\375",        0 },
1088   { "swap",      0,  0xff6, 10, "SWAP-SPACE",           probe_swap0 },
1089   { "swap",      0,  0xff6, 10, "SWAPSPACE2",           probe_swap1 },
1090   { "swsuspend", 0,  0xff6,  9, "S1SUSPEND",            probe_swap1 },
1091   { "swsuspend", 0,  0xff6,  9, "S2SUSPEND",            probe_swap1 },
1092   { "swap",      0, 0x1ff6, 10, "SWAP-SPACE",           probe_swap0 },
1093   { "swap",      0, 0x1ff6, 10, "SWAPSPACE2",           probe_swap1 },
1094   { "swsuspend", 0, 0x1ff6,  9, "S1SUSPEND",            probe_swap1 },
1095   { "swsuspend", 0, 0x1ff6,  9, "S2SUSPEND",            probe_swap1 },
1096   { "swap",      0, 0x3ff6, 10, "SWAP-SPACE",           probe_swap0 },
1097   { "swap",      0, 0x3ff6, 10, "SWAPSPACE2",           probe_swap1 },
1098   { "swsuspend", 0, 0x3ff6,  9, "S1SUSPEND",            probe_swap1 },
1099   { "swsuspend", 0, 0x3ff6,  9, "S2SUSPEND",            probe_swap1 },
1100   { "swap",      0, 0x7ff6, 10, "SWAP-SPACE",           probe_swap0 },
1101   { "swap",      0, 0x7ff6, 10, "SWAPSPACE2",           probe_swap1 },
1102   { "swsuspend", 0, 0x7ff6,  9, "S1SUSPEND",            probe_swap1 },
1103   { "swsuspend", 0, 0x7ff6,  9, "S2SUSPEND",            probe_swap1 },
1104   { "swap",      0, 0xfff6, 10, "SWAP-SPACE",           probe_swap0 },
1105   { "swap",      0, 0xfff6, 10, "SWAPSPACE2",           probe_swap1 },
1106   { "swsuspend", 0, 0xfff6,  9, "S1SUSPEND",            probe_swap1 },
1107   { "swsuspend", 0, 0xfff6,  9, "S2SUSPEND",            probe_swap1 },
1108   { "ocfs",      0,      8,  9, "OracleCFS",            probe_ocfs },
1109   { "ocfs2",     1,      0,  6, "OCFSV2",               probe_ocfs2 },
1110   { "ocfs2",     2,      0,  6, "OCFSV2",               probe_ocfs2 },
1111   { "ocfs2",     4,      0,  6, "OCFSV2",               probe_ocfs2 },
1112   { "ocfs2",     8,      0,  6, "OCFSV2",               probe_ocfs2 },
1113   { "crypt_LUKS", 0,     0,  6, "LUKS\xba\xbe",         probe_luks },
1114   { "squashfs",  0,      0,  4, "sqsh",                 0 },
1115   { "squashfs",  0,      0,  4, "hsqs",                 0 },
1116   {   NULL,      0,      0,  0, NULL,                   NULL }
1117 };
1118
1119 /*
1120  * Verify that the data in dev is consistent with what is on the actual
1121  * block device (using the devname field only).  Normally this will be
1122  * called when finding items in the cache, but for long running processes
1123  * is also desirable to revalidate an item before use.
1124  *
1125  * If we are unable to revalidate the data, we return the old data and
1126  * do not set the BLKID_BID_FL_VERIFIED flag on it.
1127  */
1128 blkid_dev blkid_verify(blkid_cache cache, blkid_dev dev)
1129 {
1130         struct blkid_magic *id;
1131         struct blkid_probe probe;
1132         blkid_tag_iterate iter;
1133         unsigned char *buf;
1134         const char *type, *value;
1135         struct stat st;
1136         time_t diff, now;
1137         int idx;
1138
1139         if (!dev)
1140                 return NULL;
1141
1142         now = time(0);
1143         diff = now - dev->bid_time;
1144
1145         if ((now > dev->bid_time) && (diff > 0) &&
1146             ((diff < BLKID_PROBE_MIN) ||
1147              (dev->bid_flags & BLKID_BID_FL_VERIFIED &&
1148               diff < BLKID_PROBE_INTERVAL)))
1149                 return dev;
1150
1151         DBG(DEBUG_PROBE,
1152             printf("need to revalidate %s (time since last check %llu)\n",
1153                    dev->bid_name, (unsigned long long)diff));
1154
1155         if (((probe.fd = open(dev->bid_name, O_RDONLY)) < 0) ||
1156             (fstat(probe.fd, &st) < 0)) {
1157                 if (probe.fd >= 0) close(probe.fd);
1158                 if (errno != EPERM) {
1159                         blkid_free_dev(dev);
1160                         return NULL;
1161                 }
1162                 /* We don't have read permission, just return cache data. */
1163                 DBG(DEBUG_PROBE,
1164                     printf("returning unverified data for %s\n",
1165                            dev->bid_name));
1166                 return dev;
1167         }
1168
1169         probe.cache = cache;
1170         probe.dev = dev;
1171         probe.sbbuf = 0;
1172         probe.buf = 0;
1173         probe.buf_max = 0;
1174
1175         /*
1176          * Iterate over the type array.  If we already know the type,
1177          * then try that first.  If it doesn't work, then blow away
1178          * the type information, and try again.
1179          *
1180          */
1181 try_again:
1182         type = 0;
1183         if (!dev->bid_type || !strcmp(dev->bid_type, "mdraid")) {
1184                 uuid_t  uuid;
1185
1186                 if (check_mdraid(probe.fd, uuid) == 0) {
1187                         set_uuid(dev, uuid, 0);
1188                         type = "mdraid";
1189                         goto found_type;
1190                 }
1191         }
1192         for (id = type_array; id->bim_type; id++) {
1193                 if (dev->bid_type &&
1194                     strcmp(id->bim_type, dev->bid_type))
1195                         continue;
1196
1197                 idx = id->bim_kboff + (id->bim_sboff >> 10);
1198                 buf = get_buffer(&probe, idx << 10, 1024);
1199                 if (!buf)
1200                         continue;
1201
1202                 if (memcmp(id->bim_magic, buf + (id->bim_sboff&0x3ff),
1203                            id->bim_len))
1204                         continue;
1205
1206                 if ((id->bim_probe == NULL) ||
1207                     (id->bim_probe(&probe, id, buf) == 0)) {
1208                         type = id->bim_type;
1209                         goto found_type;
1210                 }
1211         }
1212
1213         if (!id->bim_type && dev->bid_type) {
1214                 /*
1215                  * Zap the device filesystem information and try again
1216                  */
1217                 DBG(DEBUG_PROBE,
1218                     printf("previous fs type %s not valid, "
1219                            "trying full probe\n", dev->bid_type));
1220                 iter = blkid_tag_iterate_begin(dev);
1221                 while (blkid_tag_next(iter, &type, &value) == 0)
1222                         blkid_set_tag(dev, type, 0, 0);
1223                 blkid_tag_iterate_end(iter);
1224                 goto try_again;
1225         }
1226
1227         if (!dev->bid_type) {
1228                 blkid_free_dev(dev);
1229                 dev = 0;
1230                 goto found_type;
1231         }
1232
1233 found_type:
1234         if (dev && type) {
1235                 dev->bid_devno = st.st_rdev;
1236                 dev->bid_time = time(0);
1237                 dev->bid_flags |= BLKID_BID_FL_VERIFIED;
1238                 cache->bic_flags |= BLKID_BIC_FL_CHANGED;
1239
1240                 blkid_set_tag(dev, "TYPE", type, 0);
1241
1242                 DBG(DEBUG_PROBE, printf("%s: devno 0x%04llx, type %s\n",
1243                            dev->bid_name, (long long)st.st_rdev, type));
1244         }
1245
1246         if (probe.sbbuf)
1247                 free(probe.sbbuf);
1248         if (probe.buf)
1249                 free(probe.buf);
1250         if (probe.fd >= 0)
1251                 close(probe.fd);
1252
1253         return dev;
1254 }
1255
1256 int blkid_known_fstype(const char *fstype)
1257 {
1258         struct blkid_magic *id;
1259
1260         for (id = type_array; id->bim_type; id++) {
1261                 if (strcmp(fstype, id->bim_type) == 0)
1262                         return 1;
1263         }
1264         return 0;
1265 }
1266
1267 #ifdef TEST_PROGRAM
1268 int main(int argc, char **argv)
1269 {
1270         blkid_dev dev;
1271         blkid_cache cache;
1272         int ret;
1273
1274         if (argc != 2) {
1275                 fprintf(stderr, "Usage: %s device\n"
1276                         "Probe a single device to determine type\n", argv[0]);
1277                 exit(1);
1278         }
1279         if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
1280                 fprintf(stderr, "%s: error creating cache (%d)\n",
1281                         argv[0], ret);
1282                 exit(1);
1283         }
1284         dev = blkid_get_dev(cache, argv[1], BLKID_DEV_NORMAL);
1285         if (!dev) {
1286                 printf("%s: %s has an unsupported type\n", argv[0], argv[1]);
1287                 return (1);
1288         }
1289         printf("TYPE='%s'\n", dev->bid_type ? dev->bid_type : "(null)");
1290         if (dev->bid_label)
1291                 printf("LABEL='%s'\n", dev->bid_label);
1292         if (dev->bid_uuid)
1293                 printf("UUID='%s'\n", dev->bid_uuid);
1294
1295         blkid_free_dev(dev);
1296         return (0);
1297 }
1298 #endif