e2fsprogs/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                       const struct blkid_magic *id, unsigned char *buf)
 102 {
 103         struct ext2_super_block *es;
 104
 105         es = (struct ext2_super_block *)buf;
 106
 107         /* Distinguish between jbd and ext2/3 fs */
 108         if (blkid_le32(es->s_feature_incompat) &
 109             EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)
 110                 return -BLKID_ERR_PARAM;
 111
 112         /* Distinguish between ext3 and ext2 */
 113         if (!(blkid_le32(es->s_feature_compat) &
 114               EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 115                 return -BLKID_ERR_PARAM;
 116
 117         get_ext2_info(dev, buf);
 118
 119         blkid_set_tag(dev, "SEC_TYPE", "ext2", sizeof("ext2"));
 120
 121         return 0;
 122 }
 123
 124 static int probe_ext2(int fd __BLKID_ATTR((unused)),
 125                       blkid_cache cache __BLKID_ATTR((unused)),
 126                       blkid_dev dev,
 127                       const struct blkid_magic *id, unsigned char *buf)
 128 {
 129         struct ext2_super_block *es;
 130 //      const char *sec_type = 0, *label = 0;
 131
 132         es = (struct ext2_super_block *)buf;
 133
 134         /* Distinguish between jbd and ext2/3 fs */
 135         if (blkid_le32(es->s_feature_incompat) &
 136             EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)
 137                 return -BLKID_ERR_PARAM;
 138
 139         get_ext2_info(dev, buf);
 140
 141         return 0;
 142 }
 143
 144 static int probe_jbd(int fd __BLKID_ATTR((unused)),
 145                      blkid_cache cache __BLKID_ATTR((unused)),
 146                      blkid_dev dev,
 147                      const struct blkid_magic *id __BLKID_ATTR((unused)),
 148                      unsigned char *buf)
 149 {
 150         struct ext2_super_block *es = (struct ext2_super_block *) buf;
 151
 152         if (!(blkid_le32(es->s_feature_incompat) &
 153               EXT3_FEATURE_INCOMPAT_JOURNAL_DEV))
 154                 return -BLKID_ERR_PARAM;
 155
 156         get_ext2_info(dev, buf);
 157
 158         return 0;
 159 }
 160
 161 static int probe_vfat(int fd __BLKID_ATTR((unused)),
 162                       blkid_cache cache __BLKID_ATTR((unused)),
 163                       blkid_dev dev,
 164                       const struct blkid_magic *id __BLKID_ATTR((unused)),
 165                       unsigned char *buf)
 166 {
 167         struct vfat_super_block *vs;
 168         char serno[10];
 169         const char *label = 0;
 170         int label_len = 0;
 171
 172         vs = (struct vfat_super_block *)buf;
 173
 174         if (strncmp(vs->vs_label, "NO NAME", 7)) {
 175                 char *end = vs->vs_label + sizeof(vs->vs_label) - 1;
 176
 177                 while (*end == ' ' && end >= vs->vs_label)
 178                         --end;
 179                 if (end >= vs->vs_label) {
 180                         label = vs->vs_label;
 181                         label_len = end - vs->vs_label + 1;
 182                 }
 183         }
 184
 185         /* We can't just print them as %04X, because they are unaligned */
 186         sprintf(serno, "%02X%02X-%02X%02X", vs->vs_serno[3], vs->vs_serno[2],
 187                 vs->vs_serno[1], vs->vs_serno[0]);
 188         blkid_set_tag(dev, "LABEL", label, label_len);
 189         blkid_set_tag(dev, "UUID", serno, sizeof(serno));
 190
 191         return 0;
 192 }
 193
 194 static int probe_msdos(int fd __BLKID_ATTR((unused)),
 195                        blkid_cache cache __BLKID_ATTR((unused)),
 196                        blkid_dev dev,
 197                        const struct blkid_magic *id __BLKID_ATTR((unused)),
 198                        unsigned char *buf)
 199 {
 200         struct msdos_super_block *ms = (struct msdos_super_block *) buf;
 201         char serno[10];
 202         const char *label = 0;
 203         int label_len = 0;
 204
 205         if (strncmp(ms->ms_label, "NO NAME", 7)) {
 206                 char *end = ms->ms_label + sizeof(ms->ms_label) - 1;
 207
 208                 while (*end == ' ' && end >= ms->ms_label)
 209                         --end;
 210                 if (end >= ms->ms_label) {
 211                         label = ms->ms_label;
 212                         label_len = end - ms->ms_label + 1;
 213                 }
 214         }
 215
 216         /* We can't just print them as %04X, because they are unaligned */
 217         sprintf(serno, "%02X%02X-%02X%02X", ms->ms_serno[3], ms->ms_serno[2],
 218                 ms->ms_serno[1], ms->ms_serno[0]);
 219         blkid_set_tag(dev, "UUID", serno, 0);
 220         blkid_set_tag(dev, "LABEL", label, label_len);
 221         blkid_set_tag(dev, "SEC_TYPE", "msdos", sizeof("msdos"));
 222
 223         return 0;
 224 }
 225
 226 static int probe_xfs(int fd __BLKID_ATTR((unused)),
 227                      blkid_cache cache __BLKID_ATTR((unused)),
 228                      blkid_dev dev,
 229                      const struct blkid_magic *id __BLKID_ATTR((unused)),
 230                      unsigned char *buf)
 231 {
 232         struct xfs_super_block *xs;
 233         const char *label = 0;
 234
 235         xs = (struct xfs_super_block *)buf;
 236
 237         if (strlen(xs->xs_fname))
 238                 label = xs->xs_fname;
 239         blkid_set_tag(dev, "LABEL", label, sizeof(xs->xs_fname));
 240         set_uuid(dev, xs->xs_uuid);
 241         return 0;
 242 }
 243
 244 static int probe_reiserfs(int fd __BLKID_ATTR((unused)),
 245                           blkid_cache cache __BLKID_ATTR((unused)),
 246                           blkid_dev dev,
 247                           const struct blkid_magic *id, unsigned char *buf)
 248 {
 249         struct reiserfs_super_block *rs = (struct reiserfs_super_block *) buf;
 250         unsigned int blocksize;
 251         const char *label = 0;
 252
 253         blocksize = blkid_le16(rs->rs_blocksize);
 254
 255         /* If the superblock is inside the journal, we have the wrong one */
 256         if (id->bim_kboff/(blocksize>>10) > blkid_le32(rs->rs_journal_block))
 257                 return -BLKID_ERR_BIG;
 258
 259         /* LABEL/UUID are only valid for later versions of Reiserfs v3.6. */
 260         if (!strcmp(id->bim_magic, "ReIsEr2Fs") ||
 261             !strcmp(id->bim_magic, "ReIsEr3Fs")) {
 262                 if (strlen(rs->rs_label))
 263                         label = rs->rs_label;
 264                 set_uuid(dev, rs->rs_uuid);
 265         }
 266         blkid_set_tag(dev, "LABEL", label, sizeof(rs->rs_label));
 267
 268         return 0;
 269 }
 270
 271 static int probe_jfs(int fd __BLKID_ATTR((unused)),
 272                      blkid_cache cache __BLKID_ATTR((unused)),
 273                      blkid_dev dev,
 274                      const struct blkid_magic *id __BLKID_ATTR((unused)),
 275                      unsigned char *buf)
 276 {
 277         struct jfs_super_block *js;
 278         const char *label = 0;
 279
 280         js = (struct jfs_super_block *)buf;
 281
 282         if (strlen((char *) js->js_label))
 283                 label = (char *) js->js_label;
 284         blkid_set_tag(dev, "LABEL", label, sizeof(js->js_label));
 285         set_uuid(dev, js->js_uuid);
 286         return 0;
 287 }
 288
 289 static int probe_romfs(int fd __BLKID_ATTR((unused)),
 290                        blkid_cache cache __BLKID_ATTR((unused)),
 291                        blkid_dev dev,
 292                        const struct blkid_magic *id __BLKID_ATTR((unused)),
 293                        unsigned char *buf)
 294 {
 295         struct romfs_super_block *ros;
 296         const char *label = 0;
 297
 298         ros = (struct romfs_super_block *)buf;
 299
 300         if (strlen((char *) ros->ros_volume))
 301                 label = (char *) ros->ros_volume;
 302         blkid_set_tag(dev, "LABEL", label, 0);
 303         return 0;
 304 }
 305
 306 static int probe_swap0(int fd __BLKID_ATTR((unused)),
 307                        blkid_cache cache __BLKID_ATTR((unused)),
 308                        blkid_dev dev,
 309                        const struct blkid_magic *id __BLKID_ATTR((unused)),
 310                        unsigned char *buf __BLKID_ATTR((unused)))
 311 {
 312         blkid_set_tag(dev, "UUID", 0, 0);
 313         blkid_set_tag(dev, "LABEL", 0, 0);
 314         return 0;
 315 }
 316
 317 static int probe_swap1(int fd,
 318                        blkid_cache cache __BLKID_ATTR((unused)),
 319                        blkid_dev dev,
 320                        const struct blkid_magic *id __BLKID_ATTR((unused)),
 321                        unsigned char *buf __BLKID_ATTR((unused)))
 322 {
 323         struct swap_id_block *sws;
 324 //      const char *label = 0;
 325
 326         probe_swap0(fd, cache, dev, id, buf);
 327         /*
 328          * Version 1 swap headers are always located at offset of 1024
 329          * bytes, although the swap signature itself is located at the
 330          * end of the page (which may vary depending on hardware
 331          * pagesize).
 332          */
 333         if (lseek(fd, 1024, SEEK_SET) < 0) return 1;
 334         sws = (struct swap_id_block *)xmalloc(1024);
 335         if (read(fd, sws, 1024) != 1024) {
 336                 free(sws);
 337                 return 1;
 338         }
 339
 340         /* arbitrary sanity check.. is there any garbage down there? */
 341         if (sws->sws_pad[32] == 0 && sws->sws_pad[33] == 0)  {
 342                 if (sws->sws_volume[0])
 343                         blkid_set_tag(dev, "LABEL", (const char*)sws->sws_volume,
 344                                       sizeof(sws->sws_volume));
 345                 if (sws->sws_uuid[0])
 346                         set_uuid(dev, sws->sws_uuid);
 347         }
 348         free(sws);
 349
 350         return 0;
 351 }
 352
 353 static const char
 354 * const udf_magic[] = { "BEA01", "BOOT2", "CD001", "CDW02", "NSR02",
 355                  "NSR03", "TEA01", 0 };
 356
 357 static int probe_udf(int fd, blkid_cache cache __BLKID_ATTR((unused)),
 358                      blkid_dev dev __BLKID_ATTR((unused)),
 359                      const struct blkid_magic *id __BLKID_ATTR((unused)),
 360                      unsigned char *buf __BLKID_ATTR((unused)))
 361 {
 362         int j, bs;
 363         struct iso_volume_descriptor isosb;
 364         const char * const * m;
 365
 366         /* determine the block size by scanning in 2K increments
 367            (block sizes larger than 2K will be null padded) */
 368         for (bs = 1; bs < 16; bs++) {
 369                 lseek(fd, bs*2048+32768, SEEK_SET);
 370                 if (read(fd, (char *)&isosb, sizeof(isosb)) != sizeof(isosb))
 371                         return 1;
 372                 if (isosb.id[0])
 373                         break;
 374         }
 375
 376         /* Scan up to another 64 blocks looking for additional VSD's */
 377         for (j = 1; j < 64; j++) {
 378                 if (j > 1) {
 379                         lseek(fd, j*bs*2048+32768, SEEK_SET);
 380                         if (read(fd, (char *)&isosb, sizeof(isosb))
 381                             != sizeof(isosb))
 382                                 return 1;
 383                 }
 384                 /* If we find NSR0x then call it udf:
 385                    NSR01 for UDF 1.00
 386                    NSR02 for UDF 1.50
 387                    NSR03 for UDF 2.00 */
 388                 if (!strncmp(isosb.id, "NSR0", 4))
 389                         return 0;
 390                 for (m = udf_magic; *m; m++)
 391                         if (!strncmp(*m, isosb.id, 5))
 392                                 break;
 393                 if (*m == 0)
 394                         return 1;
 395         }
 396         return 1;
 397 }
 398
 399 static int probe_ocfs(int fd __BLKID_ATTR((unused)),
 400                       blkid_cache cache __BLKID_ATTR((unused)),
 401                       blkid_dev dev,
 402                       const struct blkid_magic *id __BLKID_ATTR((unused)),
 403                       unsigned char *buf)
 404 {
 405         struct ocfs_volume_header ovh;
 406         struct ocfs_volume_label ovl;
 407         __u32 major;
 408
 409         memcpy(&ovh, buf, sizeof(ovh));
 410         memcpy(&ovl, buf+512, sizeof(ovl));
 411
 412         major = ocfsmajor(ovh);
 413         if (major == 1)
 414                 blkid_set_tag(dev,"SEC_TYPE","ocfs1",sizeof("ocfs1"));
 415         else if (major >= 9)
 416                 blkid_set_tag(dev,"SEC_TYPE","ntocfs",sizeof("ntocfs"));
 417
 418         blkid_set_tag(dev, "LABEL", (const char*)ovl.label, ocfslabellen(ovl));
 419         blkid_set_tag(dev, "MOUNT", (const char*)ovh.mount, ocfsmountlen(ovh));
 420         set_uuid(dev, ovl.vol_id);
 421         return 0;
 422 }
 423
 424 static int probe_ocfs2(int fd __BLKID_ATTR((unused)),
 425                        blkid_cache cache __BLKID_ATTR((unused)),
 426                        blkid_dev dev,
 427                        const struct blkid_magic *id __BLKID_ATTR((unused)),
 428                        unsigned char *buf)
 429 {
 430         struct ocfs2_super_block *osb;
 431
 432         osb = (struct ocfs2_super_block *)buf;
 433
 434         blkid_set_tag(dev, "LABEL", (const char*)osb->s_label, sizeof(osb->s_label));
 435         set_uuid(dev, osb->s_uuid);
 436         return 0;
 437 }
 438
 439 static int probe_oracleasm(int fd __BLKID_ATTR((unused)),
 440                            blkid_cache cache __BLKID_ATTR((unused)),
 441                            blkid_dev dev,
 442                            const struct blkid_magic *id __BLKID_ATTR((unused)),
 443                            unsigned char *buf)
 444 {
 445         struct oracle_asm_disk_label *dl;
 446
 447         dl = (struct oracle_asm_disk_label *)buf;
 448
 449         blkid_set_tag(dev, "LABEL", dl->dl_id, sizeof(dl->dl_id));
 450         return 0;
 451 }
 452
 453 /*
 454  * BLKID_BLK_OFFS is at least as large as the highest bim_kboff defined
 455  * in the type_array table below + bim_kbalign.
 456  *
 457  * When probing for a lot of magics, we handle everything in 1kB buffers so
 458  * that we don't have to worry about reading each combination of block sizes.
 459  */
 460 #define BLKID_BLK_OFFS  64      /* currently reiserfs */
 461
 462 /*
 463  * Various filesystem magics that we can check for.  Note that kboff and
 464  * sboff are in kilobytes and bytes respectively.  All magics are in
 465  * byte strings so we don't worry about endian issues.
 466  */
 467 static const struct blkid_magic type_array[] = {
 468 /*  type     kboff   sboff len  magic                   probe */
 469   { "oracleasm", 0,     32,  8, "ORCLDISK",             probe_oracleasm },
 470   { "ntfs",      0,      3,  8, "NTFS    ",             0 },
 471   { "jbd",       1,   0x38,  2, "\123\357",             probe_jbd },
 472   { "ext3",      1,   0x38,  2, "\123\357",             probe_ext3 },
 473   { "ext2",      1,   0x38,  2, "\123\357",             probe_ext2 },
 474   { "reiserfs",  8,   0x34,  8, "ReIsErFs",             probe_reiserfs },
 475   { "reiserfs", 64,   0x34,  9, "ReIsEr2Fs",            probe_reiserfs },
 476   { "reiserfs", 64,   0x34,  9, "ReIsEr3Fs",            probe_reiserfs },
 477   { "reiserfs", 64,   0x34,  8, "ReIsErFs",             probe_reiserfs },
 478   { "reiserfs",  8,     20,  8, "ReIsErFs",             probe_reiserfs },
 479   { "vfat",      0,   0x52,  5, "MSWIN",                probe_vfat },
 480   { "vfat",      0,   0x52,  8, "FAT32   ",             probe_vfat },
 481   { "vfat",      0,   0x36,  5, "MSDOS",                probe_msdos },
 482   { "vfat",      0,   0x36,  8, "FAT16   ",             probe_msdos },
 483   { "vfat",      0,   0x36,  8, "FAT12   ",             probe_msdos },
 484   { "minix",     1,   0x10,  2, "\177\023",             0 },
 485   { "minix",     1,   0x10,  2, "\217\023",             0 },
 486   { "minix",     1,   0x10,  2, "\150\044",             0 },
 487   { "minix",     1,   0x10,  2, "\170\044",             0 },
 488   { "vxfs",      1,      0,  4, "\365\374\001\245",     0 },
 489   { "xfs",       0,      0,  4, "XFSB",                 probe_xfs },
 490   { "romfs",     0,      0,  8, "-rom1fs-",             probe_romfs },
 491   { "bfs",       0,      0,  4, "\316\372\173\033",     0 },
 492   { "cramfs",    0,      0,  4, "E=\315\034",           0 },
 493   { "qnx4",      0,      4,  6, "QNX4FS",               0 },
 494   { "udf",      32,      1,  5, "BEA01",                probe_udf },
 495   { "udf",      32,      1,  5, "BOOT2",                probe_udf },
 496   { "udf",      32,      1,  5, "CD001",                probe_udf },
 497   { "udf",      32,      1,  5, "CDW02",                probe_udf },
 498   { "udf",      32,      1,  5, "NSR02",                probe_udf },
 499   { "udf",      32,      1,  5, "NSR03",                probe_udf },
 500   { "udf",      32,      1,  5, "TEA01",                probe_udf },
 501   { "iso9660",  32,      1,  5, "CD001",                0 },
 502   { "iso9660",  32,      9,  5, "CDROM",                0 },
 503   { "jfs",      32,      0,  4, "JFS1",                 probe_jfs },
 504   { "hfs",       1,      0,  2, "BD",                   0 },
 505   { "ufs",       8,  0x55c,  4, "T\031\001\000",        0 },
 506   { "hpfs",      8,      0,  4, "I\350\225\371",        0 },
 507   { "sysv",      0,  0x3f8,  4, "\020~\030\375",        0 },
 508   { "swap",      0,  0xff6, 10, "SWAP-SPACE",           probe_swap0 },
 509   { "swap",      0,  0xff6, 10, "SWAPSPACE2",           probe_swap1 },
 510   { "swap",      0, 0x1ff6, 10, "SWAP-SPACE",           probe_swap0 },
 511   { "swap",      0, 0x1ff6, 10, "SWAPSPACE2",           probe_swap1 },
 512   { "swap",      0, 0x3ff6, 10, "SWAP-SPACE",           probe_swap0 },
 513   { "swap",      0, 0x3ff6, 10, "SWAPSPACE2",           probe_swap1 },
 514   { "swap",      0, 0x7ff6, 10, "SWAP-SPACE",           probe_swap0 },
 515   { "swap",      0, 0x7ff6, 10, "SWAPSPACE2",           probe_swap1 },
 516   { "swap",      0, 0xfff6, 10, "SWAP-SPACE",           probe_swap0 },
 517   { "swap",      0, 0xfff6, 10, "SWAPSPACE2",           probe_swap1 },
 518   { "ocfs",      0,      8,  9, "OracleCFS",            probe_ocfs },
 519   { "ocfs2",     1,      0,  6, "OCFSV2",               probe_ocfs2 },
 520   { "ocfs2",     2,      0,  6, "OCFSV2",               probe_ocfs2 },
 521   { "ocfs2",     4,      0,  6, "OCFSV2",               probe_ocfs2 },
 522   { "ocfs2",     8,      0,  6, "OCFSV2",               probe_ocfs2 },
 523   {   NULL,      0,      0,  0, NULL,                   NULL }
 524 };
 525
 526 /*
 527  * Verify that the data in dev is consistent with what is on the actual
 528  * block device (using the devname field only).  Normally this will be
 529  * called when finding items in the cache, but for long running processes
 530  * is also desirable to revalidate an item before use.
 531  *
 532  * If we are unable to revalidate the data, we return the old data and
 533  * do not set the BLKID_BID_FL_VERIFIED flag on it.
 534  */
 535 blkid_dev blkid_verify(blkid_cache cache, blkid_dev dev)
 536 {
 537         const struct blkid_magic *id;
 538         unsigned char *bufs[BLKID_BLK_OFFS + 1], *buf;
 539         const char *type;
 540         struct stat st;
 541         time_t diff, now;
 542         int fd, idx;
 543
 544         if (!dev)
 545                 return NULL;
 546
 547         now = time(0);
 548         diff = now - dev->bid_time;
 549
 550         if ((now < dev->bid_time) ||
 551             (diff < BLKID_PROBE_MIN) ||
 552             (dev->bid_flags & BLKID_BID_FL_VERIFIED &&
 553              diff < BLKID_PROBE_INTERVAL))
 554                 return dev;
 555
 556         DBG(DEBUG_PROBE,
 557             printf("need to revalidate %s (time since last check %lu)\n",
 558                    dev->bid_name, diff));
 559
 560         if (((fd = open(dev->bid_name, O_RDONLY)) < 0) ||
 561             (fstat(fd, &st) < 0)) {
 562                 if (errno == ENXIO || errno == ENODEV || errno == ENOENT) {
 563                         blkid_free_dev(dev);
 564                         return NULL;
 565                 }
 566                 /* We don't have read permission, just return cache data. */
 567                 DBG(DEBUG_PROBE,
 568                     printf("returning unverified data for %s\n",
 569                            dev->bid_name));
 570                 return dev;
 571         }
 572
 573         memset(bufs, 0, sizeof(bufs));
 574
 575         /*
 576          * Iterate over the type array.  If we already know the type,
 577          * then try that first.  If it doesn't work, then blow away
 578          * the type information, and try again.
 579          *
 580          */
 581 try_again:
 582         type = 0;
 583         if (!dev->bid_type || !strcmp(dev->bid_type, "mdraid")) {
 584                 uuid_t  uuid;
 585
 586                 if (check_mdraid(fd, uuid) == 0) {
 587                         set_uuid(dev, uuid);
 588                         type = "mdraid";
 589                         goto found_type;
 590                 }
 591         }
 592         for (id = type_array; id->bim_type; id++) {
 593                 if (dev->bid_type &&
 594                     strcmp(id->bim_type, dev->bid_type))
 595                         continue;
 596
 597                 idx = id->bim_kboff + (id->bim_sboff >> 10);
 598                 if (idx > BLKID_BLK_OFFS || idx < 0)
 599                         continue;
 600                 buf = bufs[idx];
 601                 if (!buf) {
 602                         if (lseek(fd, idx << 10, SEEK_SET) < 0)
 603                                 continue;
 604
 605                         buf = (unsigned char *)xmalloc(1024);
 606
 607                         if (read(fd, buf, 1024) != 1024) {
 608                                 free(buf);
 609                                 continue;
 610                         }
 611                         bufs[idx] = buf;
 612                 }
 613
 614                 if (memcmp(id->bim_magic, buf + (id->bim_sboff&0x3ff),
 615                            id->bim_len))
 616                         continue;
 617
 618                 if ((id->bim_probe == NULL) ||
 619                     (id->bim_probe(fd, cache, dev, id, buf) == 0)) {
 620                         type = id->bim_type;
 621                         goto found_type;
 622                 }
 623         }
 624
 625         if (!id->bim_type && dev->bid_type) {
 626                 /*
 627                  * Zap the device filesystem type and try again
 628                  */
 629                 blkid_set_tag(dev, "TYPE", 0, 0);
 630                 blkid_set_tag(dev, "SEC_TYPE", 0, 0);
 631                 blkid_set_tag(dev, "LABEL", 0, 0);
 632                 blkid_set_tag(dev, "UUID", 0, 0);
 633                 goto try_again;
 634         }
 635
 636         if (!dev->bid_type) {
 637                 blkid_free_dev(dev);
 638                 return NULL;
 639         }
 640
 641 found_type:
 642         if (dev && type) {
 643                 dev->bid_devno = st.st_rdev;
 644                 dev->bid_time = time(0);
 645                 dev->bid_flags |= BLKID_BID_FL_VERIFIED;
 646                 cache->bic_flags |= BLKID_BIC_FL_CHANGED;
 647
 648                 blkid_set_tag(dev, "TYPE", type, 0);
 649
 650                 DBG(DEBUG_PROBE, printf("%s: devno 0x%04Lx, type %s\n",
 651                            dev->bid_name, st.st_rdev, type));
 652         }
 653
 654         close(fd);
 655
 656         return dev;
 657 }
 658
 659 int blkid_known_fstype(const char *fstype)
 660 {
 661         const struct blkid_magic *id;
 662
 663         for (id = type_array; id->bim_type; id++) {
 664                 if (strcmp(fstype, id->bim_type) == 0)
 665                         return 1;
 666         }
 667         return 0;
 668 }
 669
 670 #ifdef TEST_PROGRAM
 671 int main(int argc, char **argv)
 672 {
 673         blkid_dev dev;
 674         blkid_cache cache;
 675         int ret;
 676
 677         blkid_debug_mask = DEBUG_ALL;
 678         if (argc != 2) {
 679                 fprintf(stderr, "Usage: %s device\n"
 680                         "Probe a single device to determine type\n", argv[0]);
 681                 exit(1);
 682         }
 683         if ((ret = blkid_get_cache(&cache, bb_dev_null)) != 0) {
 684                 fprintf(stderr, "%s: error creating cache (%d)\n",
 685                         argv[0], ret);
 686                 exit(1);
 687         }
 688         dev = blkid_get_dev(cache, argv[1], BLKID_DEV_NORMAL);
 689         if (!dev) {
 690                 printf("%s: %s has an unsupported type\n", argv[0], argv[1]);
 691                 return (1);
 692         }
 693         printf("%s is type %s\n", argv[1], dev->bid_type ?
 694                 dev->bid_type : "(null)");
 695         if (dev->bid_label)
 696                 printf("\tlabel is '%s'\n", dev->bid_label);
 697         if (dev->bid_uuid)
 698                 printf("\tuuid is %s\n", dev->bid_uuid);
 699
 700         blkid_free_dev(dev);
 701         return (0);
 702 }
 703 #endif