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  *
   9  * %Begin-Header%
  10  * This file may be redistributed under the terms of the
  11  * GNU Lesser General Public License.
  12  * %End-Header%
  13  */
  14
  15 #include <stdio.h>
  16 #include <string.h>
  17 #include <stdlib.h>
  18 #include <unistd.h>
  19 #include <fcntl.h>
  20 #include <sys/types.h>
  21 #ifdef HAVE_SYS_STAT_H
  22 #include <sys/stat.h>
  23 #endif
  24 #ifdef HAVE_SYS_MKDEV_H
  25 #include <sys/mkdev.h>
  26 #endif
  27 #ifdef HAVE_ERRNO_H
  28 #include <errno.h>
  29 #endif
  30 #include "blkidP.h"
  31 #include "uuid/uuid.h"
  32 #include "probe.h"
  33
  34 /*
  35  * This is a special case code to check for an MDRAID device.  We do
  36  * this special since it requires checking for a superblock at the end
  37  * of the device.
  38  */
  39 static int check_mdraid(int fd, unsigned char *ret_uuid)
  40 {
  41         struct mdp_superblock_s *md;
  42         blkid_loff_t            offset;
  43         char                    buf[4096];
  44
  45         if (fd < 0)
  46                 return -BLKID_ERR_PARAM;
  47
  48         offset = (blkid_get_dev_size(fd) & ~((blkid_loff_t)65535)) - 65536;
  49
  50         if (blkid_llseek(fd, offset, 0) < 0 ||
  51             read(fd, buf, 4096) != 4096)
  52                 return -BLKID_ERR_IO;
  53
  54         /* Check for magic number */
  55         if (memcmp("\251+N\374", buf, 4))
  56                 return -BLKID_ERR_PARAM;
  57
  58         if (!ret_uuid)
  59                 return 0;
  60         *ret_uuid = 0;
  61
  62         /* The MD UUID is not contiguous in the superblock, make it so */
  63         md = (struct mdp_superblock_s *)buf;
  64         if (md->set_uuid0 || md->set_uuid1 || md->set_uuid2 || md->set_uuid3) {
  65                 memcpy(ret_uuid, &md->set_uuid0, 4);
  66                 memcpy(ret_uuid, &md->set_uuid1, 12);
  67         }
  68         return 0;
  69 }
  70
  71 static void set_uuid(blkid_dev dev, uuid_t uuid)
  72 {
  73         char    str[37];
  74
  75         if (!uuid_is_null(uuid)) {
  76                 uuid_unparse(uuid, str);
  77                 blkid_set_tag(dev, "UUID", str, sizeof(str));
  78         }
  79 }
  80
  81 static void get_ext2_info(blkid_dev dev, unsigned char *buf)
  82 {
  83         struct ext2_super_block *es = (struct ext2_super_block *) buf;
  84         const char *label = 0;
  85
  86         DBG(DEBUG_PROBE, printf("ext2_sb.compat = %08X:%08X:%08X\n",
  87                    blkid_le32(es->s_feature_compat),
  88                    blkid_le32(es->s_feature_incompat),
  89                    blkid_le32(es->s_feature_ro_compat)));
  90
  91         if (strlen(es->s_volume_name))
  92                 label = es->s_volume_name;
  93         blkid_set_tag(dev, "LABEL", label, sizeof(es->s_volume_name));
  94
  95         set_uuid(dev, es->s_uuid);
  96 }
  97
  98 static int probe_ext3(int fd __BLKID_ATTR((unused)),
  99                       blkid_cache cache __BLKID_ATTR((unused)),
 100                       blkid_dev dev,
 101                       struct blkid_magic *id __BLKID_ATTR((unused)),
 102                       unsigned char *buf)
 103 {
 104         struct ext2_super_block *es;
 105
 106         es = (struct ext2_super_block *)buf;
 107
 108         /* Distinguish between jbd and ext2/3 fs */
 109         if (blkid_le32(es->s_feature_incompat) &
 110             EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)
 111                 return -BLKID_ERR_PARAM;
 112
 113         /* Distinguish between ext3 and ext2 */
 114         if (!(blkid_le32(es->s_feature_compat) &
 115               EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 116                 return -BLKID_ERR_PARAM;
 117
 118         get_ext2_info(dev, buf);
 119
 120         blkid_set_tag(dev, "SEC_TYPE", "ext2", sizeof("ext2"));
 121
 122         return 0;
 123 }
 124
 125 static int probe_ext2(int fd __BLKID_ATTR((unused)),
 126                       blkid_cache cache __BLKID_ATTR((unused)),
 127                       blkid_dev dev,
 128                       struct blkid_magic *id __BLKID_ATTR((unused)),
 129                       unsigned char *buf)
 130 {
 131         struct ext2_super_block *es;
 132
 133         es = (struct ext2_super_block *)buf;
 134
 135         /* Distinguish between jbd and ext2/3 fs */
 136         if (blkid_le32(es->s_feature_incompat) &
 137             EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)
 138                 return -BLKID_ERR_PARAM;
 139
 140         /* Distinguish between ext3 and ext2 */
 141         if ((blkid_le32(es->s_feature_compat) &
 142               EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 143                 return -BLKID_ERR_PARAM;
 144
 145         get_ext2_info(dev, buf);
 146
 147         return 0;
 148 }
 149
 150 static int probe_jbd(int fd __BLKID_ATTR((unused)),
 151                      blkid_cache cache __BLKID_ATTR((unused)),
 152                      blkid_dev dev,
 153                      struct blkid_magic *id __BLKID_ATTR((unused)),
 154                      unsigned char *buf)
 155 {
 156         struct ext2_super_block *es = (struct ext2_super_block *) buf;
 157
 158         if (!(blkid_le32(es->s_feature_incompat) &
 159               EXT3_FEATURE_INCOMPAT_JOURNAL_DEV))
 160                 return -BLKID_ERR_PARAM;
 161
 162         get_ext2_info(dev, buf);
 163
 164         return 0;
 165 }
 166
 167 static int probe_vfat(int fd __BLKID_ATTR((unused)),
 168                       blkid_cache cache __BLKID_ATTR((unused)),
 169                       blkid_dev dev,
 170                       struct blkid_magic *id __BLKID_ATTR((unused)),
 171                       unsigned char *buf)
 172 {
 173         struct vfat_super_block *vs;
 174         char serno[10];
 175         const char *label = 0;
 176         int label_len = 0;
 177
 178         vs = (struct vfat_super_block *)buf;
 179
 180         if (strncmp(vs->vs_label, "NO NAME", 7)) {
 181                 char *end = vs->vs_label + sizeof(vs->vs_label) - 1;
 182
 183                 while (*end == ' ' && end >= vs->vs_label)
 184                         --end;
 185                 if (end >= vs->vs_label) {
 186                         label = vs->vs_label;
 187                         label_len = end - vs->vs_label + 1;
 188                 }
 189         }
 190
 191         /* We can't just print them as %04X, because they are unaligned */
 192         sprintf(serno, "%02X%02X-%02X%02X", vs->vs_serno[3], vs->vs_serno[2],
 193                 vs->vs_serno[1], vs->vs_serno[0]);
 194         blkid_set_tag(dev, "LABEL", label, label_len);
 195         blkid_set_tag(dev, "UUID", serno, sizeof(serno));
 196
 197         return 0;
 198 }
 199
 200 static int probe_msdos(int fd __BLKID_ATTR((unused)),
 201                        blkid_cache cache __BLKID_ATTR((unused)),
 202                        blkid_dev dev,
 203                        struct blkid_magic *id __BLKID_ATTR((unused)),
 204                        unsigned char *buf)
 205 {
 206         struct msdos_super_block *ms = (struct msdos_super_block *) buf;
 207         char serno[10];
 208         const char *label = 0;
 209         int label_len = 0;
 210
 211         if (strncmp(ms->ms_label, "NO NAME", 7)) {
 212                 char *end = ms->ms_label + sizeof(ms->ms_label) - 1;
 213
 214                 while (*end == ' ' && end >= ms->ms_label)
 215                         --end;
 216                 if (end >= ms->ms_label) {
 217                         label = ms->ms_label;
 218                         label_len = end - ms->ms_label + 1;
 219                 }
 220         }
 221
 222         /* We can't just print them as %04X, because they are unaligned */
 223         sprintf(serno, "%02X%02X-%02X%02X", ms->ms_serno[3], ms->ms_serno[2],
 224                 ms->ms_serno[1], ms->ms_serno[0]);
 225         blkid_set_tag(dev, "UUID", serno, 0);
 226         blkid_set_tag(dev, "LABEL", label, label_len);
 227         blkid_set_tag(dev, "SEC_TYPE", "msdos", sizeof("msdos"));
 228
 229         return 0;
 230 }
 231
 232 static int probe_xfs(int fd __BLKID_ATTR((unused)),
 233                      blkid_cache cache __BLKID_ATTR((unused)),
 234                      blkid_dev dev,
 235                      struct blkid_magic *id __BLKID_ATTR((unused)),
 236                      unsigned char *buf)
 237 {
 238         struct xfs_super_block *xs;
 239         const char *label = 0;
 240
 241         xs = (struct xfs_super_block *)buf;
 242
 243         if (strlen(xs->xs_fname))
 244                 label = xs->xs_fname;
 245         blkid_set_tag(dev, "LABEL", label, sizeof(xs->xs_fname));
 246         set_uuid(dev, xs->xs_uuid);
 247         return 0;
 248 }
 249
 250 static int probe_reiserfs(int fd __BLKID_ATTR((unused)),
 251                           blkid_cache cache __BLKID_ATTR((unused)),
 252                           blkid_dev dev,
 253                           struct blkid_magic *id, unsigned char *buf)
 254 {
 255         struct reiserfs_super_block *rs = (struct reiserfs_super_block *) buf;
 256         unsigned int blocksize;
 257         const char *label = 0;
 258
 259         blocksize = blkid_le16(rs->rs_blocksize);
 260
 261         /* If the superblock is inside the journal, we have the wrong one */
 262         if (id->bim_kboff/(blocksize>>10) > blkid_le32(rs->rs_journal_block))
 263                 return -BLKID_ERR_BIG;
 264
 265         /* LABEL/UUID are only valid for later versions of Reiserfs v3.6. */
 266         if (!strcmp(id->bim_magic, "ReIsEr2Fs") ||
 267             !strcmp(id->bim_magic, "ReIsEr3Fs")) {
 268                 if (strlen(rs->rs_label))
 269                         label = rs->rs_label;
 270                 set_uuid(dev, rs->rs_uuid);
 271         }
 272         blkid_set_tag(dev, "LABEL", label, sizeof(rs->rs_label));
 273
 274         return 0;
 275 }
 276
 277 static int probe_jfs(int fd __BLKID_ATTR((unused)),
 278                      blkid_cache cache __BLKID_ATTR((unused)),
 279                      blkid_dev dev,
 280                      struct blkid_magic *id __BLKID_ATTR((unused)),
 281                      unsigned char *buf)
 282 {
 283         struct jfs_super_block *js;
 284         const char *label = 0;
 285
 286         js = (struct jfs_super_block *)buf;
 287
 288         if (strlen((char *) js->js_label))
 289                 label = (char *) js->js_label;
 290         blkid_set_tag(dev, "LABEL", label, sizeof(js->js_label));
 291         set_uuid(dev, js->js_uuid);
 292         return 0;
 293 }
 294
 295 static int probe_romfs(int fd __BLKID_ATTR((unused)),
 296                        blkid_cache cache __BLKID_ATTR((unused)),
 297                        blkid_dev dev,
 298                        struct blkid_magic *id __BLKID_ATTR((unused)),
 299                        unsigned char *buf)
 300 {
 301         struct romfs_super_block *ros;
 302         const char *label = 0;
 303
 304         ros = (struct romfs_super_block *)buf;
 305
 306         if (strlen((char *) ros->ros_volume))
 307                 label = (char *) ros->ros_volume;
 308         blkid_set_tag(dev, "LABEL", label, 0);
 309         return 0;
 310 }
 311
 312 static int probe_cramfs(int fd __BLKID_ATTR((unused)),
 313                        blkid_cache cache __BLKID_ATTR((unused)),
 314                        blkid_dev dev,
 315                        struct blkid_magic *id __BLKID_ATTR((unused)),
 316                        unsigned char *buf)
 317 {
 318         struct cramfs_super_block *csb;
 319         const char *label = 0;
 320
 321         csb = (struct cramfs_super_block *)buf;
 322
 323         if (strlen((char *) csb->name))
 324                 label = (char *) csb->name;
 325         blkid_set_tag(dev, "LABEL", label, 0);
 326         return 0;
 327 }
 328
 329 static int probe_swap0(int fd __BLKID_ATTR((unused)),
 330                        blkid_cache cache __BLKID_ATTR((unused)),
 331                        blkid_dev dev,
 332                        struct blkid_magic *id __BLKID_ATTR((unused)),
 333                        unsigned char *buf __BLKID_ATTR((unused)))
 334 {
 335         blkid_set_tag(dev, "UUID", 0, 0);
 336         blkid_set_tag(dev, "LABEL", 0, 0);
 337         return 0;
 338 }
 339
 340 static int probe_swap1(int fd,
 341                        blkid_cache cache __BLKID_ATTR((unused)),
 342                        blkid_dev dev,
 343                        struct blkid_magic *id __BLKID_ATTR((unused)),
 344                        unsigned char *buf __BLKID_ATTR((unused)))
 345 {
 346         struct swap_id_block *sws;
 347
 348         probe_swap0(fd, cache, dev, id, buf);
 349         /*
 350          * Version 1 swap headers are always located at offset of 1024
 351          * bytes, although the swap signature itself is located at the
 352          * end of the page (which may vary depending on hardware
 353          * pagesize).
 354          */
 355         if (lseek(fd, 1024, SEEK_SET) < 0) return 1;
 356         if (!(sws = (struct swap_id_block *)malloc(1024))) return 1;
 357         if (read(fd, sws, 1024) != 1024) {
 358                 free(sws);
 359                 return 1;
 360         }
 361
 362         /* arbitrary sanity check.. is there any garbage down there? */
 363         if (sws->sws_pad[32] == 0 && sws->sws_pad[33] == 0)  {
 364                 if (sws->sws_volume[0])
 365                         blkid_set_tag(dev, "LABEL", sws->sws_volume,
 366                                       sizeof(sws->sws_volume));
 367                 if (sws->sws_uuid[0])
 368                         set_uuid(dev, sws->sws_uuid);
 369         }
 370         free(sws);
 371
 372         return 0;
 373 }
 374
 375 static const char
 376 *udf_magic[] = { "BEA01", "BOOT2", "CD001", "CDW02", "NSR02",
 377                  "NSR03", "TEA01", 0 };
 378
 379 static int probe_udf(int fd, blkid_cache cache __BLKID_ATTR((unused)),
 380                      blkid_dev dev __BLKID_ATTR((unused)),
 381                        struct blkid_magic *id __BLKID_ATTR((unused)),
 382                      unsigned char *buf __BLKID_ATTR((unused)))
 383 {
 384         int j, bs;
 385         struct iso_volume_descriptor isosb;
 386         const char ** m;
 387
 388         /* determine the block size by scanning in 2K increments
 389            (block sizes larger than 2K will be null padded) */
 390         for (bs = 1; bs < 16; bs++) {
 391                 lseek(fd, bs*2048+32768, SEEK_SET);
 392                 if (read(fd, (char *)&isosb, sizeof(isosb)) != sizeof(isosb))
 393                         return 1;
 394                 if (isosb.id[0])
 395                         break;
 396         }
 397
 398         /* Scan up to another 64 blocks looking for additional VSD's */
 399         for (j = 1; j < 64; j++) {
 400                 if (j > 1) {
 401                         lseek(fd, j*bs*2048+32768, SEEK_SET);
 402                         if (read(fd, (char *)&isosb, sizeof(isosb))
 403                             != sizeof(isosb))
 404                                 return 1;
 405                 }
 406                 /* If we find NSR0x then call it udf:
 407                    NSR01 for UDF 1.00
 408                    NSR02 for UDF 1.50
 409                    NSR03 for UDF 2.00 */
 410                 if (!strncmp(isosb.id, "NSR0", 4))
 411                         return 0;
 412                 for (m = udf_magic; *m; m++)
 413                         if (!strncmp(*m, isosb.id, 5))
 414                                 break;
 415                 if (*m == 0)
 416                         return 1;
 417         }
 418         return 1;
 419 }
 420
 421 static int probe_ocfs(int fd __BLKID_ATTR((unused)),
 422                       blkid_cache cache __BLKID_ATTR((unused)),
 423                       blkid_dev dev,
 424                       struct blkid_magic *id __BLKID_ATTR((unused)),
 425                       unsigned char *buf)
 426 {
 427         struct ocfs_volume_header ovh;
 428         struct ocfs_volume_label ovl;
 429         __u32 major;
 430
 431         memcpy(&ovh, buf, sizeof(ovh));
 432         memcpy(&ovl, buf+512, sizeof(ovl));
 433
 434         major = ocfsmajor(ovh);
 435         if (major == 1)
 436                 blkid_set_tag(dev,"SEC_TYPE","ocfs1",sizeof("ocfs1"));
 437         else if (major >= 9)
 438                 blkid_set_tag(dev,"SEC_TYPE","ntocfs",sizeof("ntocfs"));
 439
 440         blkid_set_tag(dev, "LABEL", ovl.label, ocfslabellen(ovl));
 441         blkid_set_tag(dev, "MOUNT", ovh.mount, ocfsmountlen(ovh));
 442         set_uuid(dev, ovl.vol_id);
 443         return 0;
 444 }
 445
 446 static int probe_ocfs2(int fd __BLKID_ATTR((unused)),
 447                        blkid_cache cache __BLKID_ATTR((unused)),
 448                        blkid_dev dev,
 449                        struct blkid_magic *id __BLKID_ATTR((unused)),
 450                        unsigned char *buf)
 451 {
 452         struct ocfs2_super_block *osb;
 453
 454         osb = (struct ocfs2_super_block *)buf;
 455
 456         blkid_set_tag(dev, "LABEL", osb->s_label, sizeof(osb->s_label));
 457         set_uuid(dev, osb->s_uuid);
 458         return 0;
 459 }
 460
 461 static int probe_oracleasm(int fd __BLKID_ATTR((unused)),
 462                            blkid_cache cache __BLKID_ATTR((unused)),
 463                            blkid_dev dev,
 464                            struct blkid_magic *id __BLKID_ATTR((unused)),
 465                            unsigned char *buf)
 466 {
 467         struct oracle_asm_disk_label *dl;
 468
 469         dl = (struct oracle_asm_disk_label *)buf;
 470
 471         blkid_set_tag(dev, "LABEL", dl->dl_id, sizeof(dl->dl_id));
 472         return 0;
 473 }
 474
 475 /*
 476  * BLKID_BLK_OFFS is at least as large as the highest bim_kboff defined
 477  * in the type_array table below + bim_kbalign.
 478  *
 479  * When probing for a lot of magics, we handle everything in 1kB buffers so
 480  * that we don't have to worry about reading each combination of block sizes.
 481  */
 482 #define BLKID_BLK_OFFS  64      /* currently reiserfs */
 483
 484 /*
 485  * Various filesystem magics that we can check for.  Note that kboff and
 486  * sboff are in kilobytes and bytes respectively.  All magics are in
 487  * byte strings so we don't worry about endian issues.
 488  */
 489 static struct blkid_magic type_array[] = {
 490 /*  type     kboff   sboff len  magic                   probe */
 491   { "oracleasm", 0,     32,  8, "ORCLDISK",             probe_oracleasm },
 492   { "ntfs",      0,      3,  8, "NTFS    ",             0 },
 493   { "jbd",       1,   0x38,  2, "\123\357",             probe_jbd },
 494   { "ext3",      1,   0x38,  2, "\123\357",             probe_ext3 },
 495   { "ext2",      1,   0x38,  2, "\123\357",             probe_ext2 },
 496   { "reiserfs",  8,   0x34,  8, "ReIsErFs",             probe_reiserfs },
 497   { "reiserfs", 64,   0x34,  9, "ReIsEr2Fs",            probe_reiserfs },
 498   { "reiserfs", 64,   0x34,  9, "ReIsEr3Fs",            probe_reiserfs },
 499   { "reiserfs", 64,   0x34,  8, "ReIsErFs",             probe_reiserfs },
 500   { "reiserfs",  8,     20,  8, "ReIsErFs",             probe_reiserfs },
 501   { "vfat",      0,   0x52,  5, "MSWIN",                probe_vfat },
 502   { "vfat",      0,   0x52,  8, "FAT32   ",             probe_vfat },
 503   { "vfat",      0,   0x36,  5, "MSDOS",                probe_msdos },
 504   { "vfat",      0,   0x36,  8, "FAT16   ",             probe_msdos },
 505   { "vfat",      0,   0x36,  8, "FAT12   ",             probe_msdos },
 506   { "minix",     1,   0x10,  2, "\177\023",             0 },
 507   { "minix",     1,   0x10,  2, "\217\023",             0 },
 508   { "minix",     1,   0x10,  2, "\150\044",             0 },
 509   { "minix",     1,   0x10,  2, "\170\044",             0 },
 510   { "vxfs",      1,      0,  4, "\365\374\001\245",     0 },
 511   { "xfs",       0,      0,  4, "XFSB",                 probe_xfs },
 512   { "romfs",     0,      0,  8, "-rom1fs-",             probe_romfs },
 513   { "bfs",       0,      0,  4, "\316\372\173\033",     0 },
 514   { "cramfs",    0,      0,  4, "E=\315\050",           probe_cramfs },
 515   { "qnx4",      0,      4,  6, "QNX4FS",               0 },
 516   { "udf",      32,      1,  5, "BEA01",                probe_udf },
 517   { "udf",      32,      1,  5, "BOOT2",                probe_udf },
 518   { "udf",      32,      1,  5, "CD001",                probe_udf },
 519   { "udf",      32,      1,  5, "CDW02",                probe_udf },
 520   { "udf",      32,      1,  5, "NSR02",                probe_udf },
 521   { "udf",      32,      1,  5, "NSR03",                probe_udf },
 522   { "udf",      32,      1,  5, "TEA01",                probe_udf },
 523   { "iso9660",  32,      1,  5, "CD001",                0 },
 524   { "iso9660",  32,      9,  5, "CDROM",                0 },
 525   { "jfs",      32,      0,  4, "JFS1",                 probe_jfs },
 526   { "hfs",       1,      0,  2, "BD",                   0 },
 527   { "ufs",       8,  0x55c,  4, "T\031\001\000",        0 },
 528   { "hpfs",      8,      0,  4, "I\350\225\371",        0 },
 529   { "sysv",      0,  0x3f8,  4, "\020~\030\375",        0 },
 530   { "swap",      0,  0xff6, 10, "SWAP-SPACE",           probe_swap0 },
 531   { "swap",      0,  0xff6, 10, "SWAPSPACE2",           probe_swap1 },
 532   { "swap",      0, 0x1ff6, 10, "SWAP-SPACE",           probe_swap0 },
 533   { "swap",      0, 0x1ff6, 10, "SWAPSPACE2",           probe_swap1 },
 534   { "swap",      0, 0x3ff6, 10, "SWAP-SPACE",           probe_swap0 },
 535   { "swap",      0, 0x3ff6, 10, "SWAPSPACE2",           probe_swap1 },
 536   { "swap",      0, 0x7ff6, 10, "SWAP-SPACE",           probe_swap0 },
 537   { "swap",      0, 0x7ff6, 10, "SWAPSPACE2",           probe_swap1 },
 538   { "swap",      0, 0xfff6, 10, "SWAP-SPACE",           probe_swap0 },
 539   { "swap",      0, 0xfff6, 10, "SWAPSPACE2",           probe_swap1 },
 540   { "ocfs",      0,      8,  9, "OracleCFS",            probe_ocfs },
 541   { "ocfs2",     1,      0,  6, "OCFSV2",               probe_ocfs2 },
 542   { "ocfs2",     2,      0,  6, "OCFSV2",               probe_ocfs2 },
 543   { "ocfs2",     4,      0,  6, "OCFSV2",               probe_ocfs2 },
 544   { "ocfs2",     8,      0,  6, "OCFSV2",               probe_ocfs2 },
 545   {   NULL,      0,      0,  0, NULL,                   NULL }
 546 };
 547
 548 /*
 549  * Verify that the data in dev is consistent with what is on the actual
 550  * block device (using the devname field only).  Normally this will be
 551  * called when finding items in the cache, but for long running processes
 552  * is also desirable to revalidate an item before use.
 553  *
 554  * If we are unable to revalidate the data, we return the old data and
 555  * do not set the BLKID_BID_FL_VERIFIED flag on it.
 556  */
 557 blkid_dev blkid_verify(blkid_cache cache, blkid_dev dev)
 558 {
 559         struct blkid_magic *id;
 560         unsigned char *bufs[BLKID_BLK_OFFS + 1], *buf;
 561         const char *type;
 562         struct stat st;
 563         time_t diff, now;
 564         int fd, idx;
 565
 566         if (!dev)
 567                 return NULL;
 568
 569         now = time(0);
 570         diff = now - dev->bid_time;
 571
 572         if ((now < dev->bid_time) ||
 573             (diff < BLKID_PROBE_MIN) ||
 574             (dev->bid_flags & BLKID_BID_FL_VERIFIED &&
 575              diff < BLKID_PROBE_INTERVAL))
 576                 return dev;
 577
 578         DBG(DEBUG_PROBE,
 579             printf("need to revalidate %s (time since last check %lu)\n",
 580                    dev->bid_name, diff));
 581
 582         if (((fd = open(dev->bid_name, O_RDONLY)) < 0) ||
 583             (fstat(fd, &st) < 0)) {
 584                 if (errno == ENXIO || errno == ENODEV || errno == ENOENT) {
 585                         blkid_free_dev(dev);
 586                         return NULL;
 587                 }
 588                 /* We don't have read permission, just return cache data. */
 589                 DBG(DEBUG_PROBE,
 590                     printf("returning unverified data for %s\n",
 591                            dev->bid_name));
 592                 return dev;
 593         }
 594
 595         memset(bufs, 0, sizeof(bufs));
 596
 597         /*
 598          * Iterate over the type array.  If we already know the type,
 599          * then try that first.  If it doesn't work, then blow away
 600          * the type information, and try again.
 601          *
 602          */
 603 try_again:
 604         type = 0;
 605         if (!dev->bid_type || !strcmp(dev->bid_type, "mdraid")) {
 606                 uuid_t  uuid;
 607
 608                 if (check_mdraid(fd, uuid) == 0) {
 609                         set_uuid(dev, uuid);
 610                         type = "mdraid";
 611                         goto found_type;
 612                 }
 613         }
 614         for (id = type_array; id->bim_type; id++) {
 615                 if (dev->bid_type &&
 616                     strcmp(id->bim_type, dev->bid_type))
 617                         continue;
 618
 619                 idx = id->bim_kboff + (id->bim_sboff >> 10);
 620                 if (idx > BLKID_BLK_OFFS || idx < 0)
 621                         continue;
 622                 buf = bufs[idx];
 623                 if (!buf) {
 624                         if (lseek(fd, idx << 10, SEEK_SET) < 0)
 625                                 continue;
 626
 627                         if (!(buf = (unsigned char *)malloc(1024)))
 628                                 continue;
 629
 630                         if (read(fd, buf, 1024) != 1024) {
 631                                 free(buf);
 632                                 continue;
 633                         }
 634                         bufs[idx] = buf;
 635                 }
 636
 637                 if (memcmp(id->bim_magic, buf + (id->bim_sboff&0x3ff),
 638                            id->bim_len))
 639                         continue;
 640
 641                 if ((id->bim_probe == NULL) ||
 642                     (id->bim_probe(fd, cache, dev, id, buf) == 0)) {
 643                         type = id->bim_type;
 644                         goto found_type;
 645                 }
 646         }
 647
 648         if (!id->bim_type && dev->bid_type) {
 649                 /*
 650                  * Zap the device filesystem type and try again
 651                  */
 652                 blkid_set_tag(dev, "TYPE", 0, 0);
 653                 blkid_set_tag(dev, "SEC_TYPE", 0, 0);
 654                 blkid_set_tag(dev, "LABEL", 0, 0);
 655                 blkid_set_tag(dev, "UUID", 0, 0);
 656                 goto try_again;
 657         }
 658
 659         if (!dev->bid_type) {
 660                 blkid_free_dev(dev);
 661                 return NULL;
 662         }
 663
 664 found_type:
 665         if (dev && type) {
 666                 dev->bid_devno = st.st_rdev;
 667                 dev->bid_time = time(0);
 668                 dev->bid_flags |= BLKID_BID_FL_VERIFIED;
 669                 cache->bic_flags |= BLKID_BIC_FL_CHANGED;
 670
 671                 blkid_set_tag(dev, "TYPE", type, 0);
 672
 673                 DBG(DEBUG_PROBE, printf("%s: devno 0x%04llx, type %s\n",
 674                            dev->bid_name, st.st_rdev, type));
 675         }
 676
 677         close(fd);
 678
 679         return dev;
 680 }
 681
 682 int blkid_known_fstype(const char *fstype)
 683 {
 684         struct blkid_magic *id;
 685
 686         for (id = type_array; id->bim_type; id++) {
 687                 if (strcmp(fstype, id->bim_type) == 0)
 688                         return 1;
 689         }
 690         return 0;
 691 }
 692
 693 #ifdef TEST_PROGRAM
 694 int main(int argc, char **argv)
 695 {
 696         blkid_dev dev;
 697         blkid_cache cache;
 698         int ret;
 699
 700         blkid_debug_mask = DEBUG_ALL;
 701         if (argc != 2) {
 702                 fprintf(stderr, "Usage: %s device\n"
 703                         "Probe a single device to determine type\n", argv[0]);
 704                 exit(1);
 705         }
 706         if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
 707                 fprintf(stderr, "%s: error creating cache (%d)\n",
 708                         argv[0], ret);
 709                 exit(1);
 710         }
 711         dev = blkid_get_dev(cache, argv[1], BLKID_DEV_NORMAL);
 712         if (!dev) {
 713                 printf("%s: %s has an unsupported type\n", argv[0], argv[1]);
 714                 return (1);
 715         }
 716         printf("%s is type %s\n", argv[1], dev->bid_type ?
 717                 dev->bid_type : "(null)");
 718         if (dev->bid_label)
 719                 printf("\tlabel is '%s'\n", dev->bid_label);
 720         if (dev->bid_uuid)
 721                 printf("\tuuid is %s\n", dev->bid_uuid);
 722
 723         blkid_free_dev(dev);
 724         return (0);
 725 }
 726 #endif