git.maemo.org Git - busybox4maemo/blob - e2fsprogs/old_e2fsprogs/blkid/probe.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * probe.c - identify a block device by its contents, and return a dev
   4  *           struct with the details
   5  *
   6  * Copyright (C) 1999 by Andries Brouwer
   7  * Copyright (C) 1999, 2000, 2003 by Theodore Ts'o
   8  * Copyright (C) 2001 by Andreas Dilger
   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 #ifdef HAVE_ERRNO_H
  29 #include <errno.h>
  30 #endif
  31 #include "blkidP.h"
  32 #include "../uuid/uuid.h"
  33 #include "probe.h"
  34
  35 /*
  36  * This is a special case code to check for an MDRAID device.  We do
  37  * this special since it requires checking for a superblock at the end
  38  * of the device.
  39  */
  40 static int check_mdraid(int fd, unsigned char *ret_uuid)
  41 {
  42         struct mdp_superblock_s *md;
  43         blkid_loff_t            offset;
  44         char                    buf[4096];
  45
  46         if (fd < 0)
  47                 return -BLKID_ERR_PARAM;
  48
  49         offset = (blkid_get_dev_size(fd) & ~((blkid_loff_t)65535)) - 65536;
  50
  51         if (blkid_llseek(fd, offset, 0) < 0 ||
  52             read(fd, buf, 4096) != 4096)
  53                 return -BLKID_ERR_IO;
  54
  55         /* Check for magic number */
  56         if (memcmp("\251+N\374", buf, 4))
  57                 return -BLKID_ERR_PARAM;
  58
  59         if (!ret_uuid)
  60                 return 0;
  61         *ret_uuid = 0;
  62
  63         /* The MD UUID is not contiguous in the superblock, make it so */
  64         md = (struct mdp_superblock_s *)buf;
  65         if (md->set_uuid0 || md->set_uuid1 || md->set_uuid2 || md->set_uuid3) {
  66                 memcpy(ret_uuid, &md->set_uuid0, 4);
  67                 memcpy(ret_uuid, &md->set_uuid1, 12);
  68         }
  69         return 0;
  70 }
  71
  72 static void set_uuid(blkid_dev dev, uuid_t uuid)
  73 {
  74         char    str[37];
  75
  76         if (!uuid_is_null(uuid)) {
  77                 uuid_unparse(uuid, str);
  78                 blkid_set_tag(dev, "UUID", str, sizeof(str));
  79         }
  80 }
  81
  82 static void get_ext2_info(blkid_dev dev, unsigned char *buf)
  83 {
  84         struct ext2_super_block *es = (struct ext2_super_block *) buf;
  85         const char *label = 0;
  86
  87         DBG(DEBUG_PROBE, printf("ext2_sb.compat = %08X:%08X:%08X\n",
  88                    blkid_le32(es->s_feature_compat),
  89                    blkid_le32(es->s_feature_incompat),
  90                    blkid_le32(es->s_feature_ro_compat)));
  91
  92         if (strlen(es->s_volume_name))
  93                 label = es->s_volume_name;
  94         blkid_set_tag(dev, "LABEL", label, sizeof(es->s_volume_name));
  95
  96         set_uuid(dev, es->s_uuid);
  97 }
  98
  99 static int probe_ext3(int fd __BLKID_ATTR((unused)),
 100                       blkid_cache cache __BLKID_ATTR((unused)),
 101                       blkid_dev dev,
 102                       const struct blkid_magic *id __BLKID_ATTR((unused)),
 103                       unsigned char *buf)
 104 {
 105         struct ext2_super_block *es;
 106
 107         es = (struct ext2_super_block *)buf;
 108
 109         /* Distinguish between jbd and ext2/3 fs */
 110         if (blkid_le32(es->s_feature_incompat) &
 111             EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)
 112                 return -BLKID_ERR_PARAM;
 113
 114         /* Distinguish between ext3 and ext2 */
 115         if (!(blkid_le32(es->s_feature_compat) &
 116               EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 117                 return -BLKID_ERR_PARAM;
 118
 119         get_ext2_info(dev, buf);
 120
 121         blkid_set_tag(dev, "SEC_TYPE", "ext2", sizeof("ext2"));
 122
 123         return 0;
 124 }
 125
 126 static int probe_ext2(int fd __BLKID_ATTR((unused)),
 127                       blkid_cache cache __BLKID_ATTR((unused)),
 128                       blkid_dev dev,
 129                       const struct blkid_magic *id __BLKID_ATTR((unused)),
 130                       unsigned char *buf)
 131 {
 132         struct ext2_super_block *es;
 133
 134         es = (struct ext2_super_block *)buf;
 135
 136         /* Distinguish between jbd and ext2/3 fs */
 137         if (blkid_le32(es->s_feature_incompat) &
 138             EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)
 139                 return -BLKID_ERR_PARAM;
 140
 141         get_ext2_info(dev, buf);
 142
 143         return 0;
 144 }
 145
 146 static int probe_jbd(int fd __BLKID_ATTR((unused)),
 147                      blkid_cache cache __BLKID_ATTR((unused)),
 148                      blkid_dev dev,
 149                      const struct blkid_magic *id __BLKID_ATTR((unused)),
 150                      unsigned char *buf)
 151 {
 152         struct ext2_super_block *es = (struct ext2_super_block *) buf;
 153
 154         if (!(blkid_le32(es->s_feature_incompat) &
 155               EXT3_FEATURE_INCOMPAT_JOURNAL_DEV))
 156                 return -BLKID_ERR_PARAM;
 157
 158         get_ext2_info(dev, buf);
 159
 160         return 0;
 161 }
 162
 163 static int probe_vfat(int fd __BLKID_ATTR((unused)),
 164                       blkid_cache cache __BLKID_ATTR((unused)),
 165                       blkid_dev dev,
 166                       const struct blkid_magic *id __BLKID_ATTR((unused)),
 167                       unsigned char *buf)
 168 {
 169         struct vfat_super_block *vs;
 170         char serno[10];
 171         const char *label = 0;
 172         int label_len = 0;
 173
 174         vs = (struct vfat_super_block *)buf;
 175
 176         if (strncmp(vs->vs_label, "NO NAME", 7)) {
 177                 char *end = vs->vs_label + sizeof(vs->vs_label) - 1;
 178
 179                 while (*end == ' ' && end >= vs->vs_label)
 180                         --end;
 181                 if (end >= vs->vs_label) {
 182                         label = vs->vs_label;
 183                         label_len = end - vs->vs_label + 1;
 184                 }
 185         }
 186
 187         /* We can't just print them as %04X, because they are unaligned */
 188         sprintf(serno, "%02X%02X-%02X%02X", vs->vs_serno[3], vs->vs_serno[2],
 189                 vs->vs_serno[1], vs->vs_serno[0]);
 190         blkid_set_tag(dev, "LABEL", label, label_len);
 191         blkid_set_tag(dev, "UUID", serno, sizeof(serno));
 192
 193         return 0;
 194 }
 195
 196 static int probe_msdos(int fd __BLKID_ATTR((unused)),
 197                        blkid_cache cache __BLKID_ATTR((unused)),
 198                        blkid_dev dev,
 199                        const struct blkid_magic *id __BLKID_ATTR((unused)),
 200                        unsigned char *buf)
 201 {
 202         struct msdos_super_block *ms = (struct msdos_super_block *) buf;
 203         char serno[10];
 204         const char *label = 0;
 205         int label_len = 0;
 206
 207         if (strncmp(ms->ms_label, "NO NAME", 7)) {
 208                 char *end = ms->ms_label + sizeof(ms->ms_label) - 1;
 209
 210                 while (*end == ' ' && end >= ms->ms_label)
 211                         --end;
 212                 if (end >= ms->ms_label) {
 213                         label = ms->ms_label;
 214                         label_len = end - ms->ms_label + 1;
 215                 }
 216         }
 217
 218         /* We can't just print them as %04X, because they are unaligned */
 219         sprintf(serno, "%02X%02X-%02X%02X", ms->ms_serno[3], ms->ms_serno[2],
 220                 ms->ms_serno[1], ms->ms_serno[0]);
 221         blkid_set_tag(dev, "UUID", serno, 0);
 222         blkid_set_tag(dev, "LABEL", label, label_len);
 223         blkid_set_tag(dev, "SEC_TYPE", "msdos", sizeof("msdos"));
 224
 225         return 0;
 226 }
 227
 228 static int probe_xfs(int fd __BLKID_ATTR((unused)),
 229                      blkid_cache cache __BLKID_ATTR((unused)),
 230                      blkid_dev dev,
 231                      const struct blkid_magic *id __BLKID_ATTR((unused)),
 232                      unsigned char *buf)
 233 {
 234         struct xfs_super_block *xs;
 235         const char *label = 0;
 236
 237         xs = (struct xfs_super_block *)buf;
 238
 239         if (strlen(xs->xs_fname))
 240                 label = xs->xs_fname;
 241         blkid_set_tag(dev, "LABEL", label, sizeof(xs->xs_fname));
 242         set_uuid(dev, xs->xs_uuid);
 243         return 0;
 244 }
 245
 246 static int probe_reiserfs(int fd __BLKID_ATTR((unused)),
 247                           blkid_cache cache __BLKID_ATTR((unused)),
 248                           blkid_dev dev,
 249                           const struct blkid_magic *id, unsigned char *buf)
 250 {
 251         struct reiserfs_super_block *rs = (struct reiserfs_super_block *) buf;
 252         unsigned int blocksize;
 253         const char *label = 0;
 254
 255         blocksize = blkid_le16(rs->rs_blocksize);
 256
 257         /* If the superblock is inside the journal, we have the wrong one */
 258         if (id->bim_kboff/(blocksize>>10) > blkid_le32(rs->rs_journal_block))
 259                 return -BLKID_ERR_BIG;
 260
 261         /* LABEL/UUID are only valid for later versions of Reiserfs v3.6. */
 262         if (!strcmp(id->bim_magic, "ReIsEr2Fs") ||
 263             !strcmp(id->bim_magic, "ReIsEr3Fs")) {
 264                 if (strlen(rs->rs_label))
 265                         label = rs->rs_label;
 266                 set_uuid(dev, rs->rs_uuid);
 267         }
 268         blkid_set_tag(dev, "LABEL", label, sizeof(rs->rs_label));
 269
 270         return 0;
 271 }
 272
 273 static int probe_jfs(int fd __BLKID_ATTR((unused)),
 274                      blkid_cache cache __BLKID_ATTR((unused)),
 275                      blkid_dev dev,
 276                      const struct blkid_magic *id __BLKID_ATTR((unused)),
 277                      unsigned char *buf)
 278 {
 279         struct jfs_super_block *js;
 280         const char *label = 0;
 281
 282         js = (struct jfs_super_block *)buf;
 283
 284         if (strlen((char *) js->js_label))
 285                 label = (char *) js->js_label;
 286         blkid_set_tag(dev, "LABEL", label, sizeof(js->js_label));
 287         set_uuid(dev, js->js_uuid);
 288         return 0;
 289 }
 290
 291 static int probe_romfs(int fd __BLKID_ATTR((unused)),
 292                        blkid_cache cache __BLKID_ATTR((unused)),
 293                        blkid_dev dev,
 294                        const struct blkid_magic *id __BLKID_ATTR((unused)),
 295                        unsigned char *buf)
 296 {
 297         struct romfs_super_block *ros;
 298         const char *label = 0;
 299
 300         ros = (struct romfs_super_block *)buf;
 301
 302         if (strlen((char *) ros->ros_volume))
 303                 label = (char *) ros->ros_volume;
 304         blkid_set_tag(dev, "LABEL", label, 0);
 305         return 0;
 306 }
 307
 308 static int probe_cramfs(int fd __BLKID_ATTR((unused)),
 309                        blkid_cache cache __BLKID_ATTR((unused)),
 310                        blkid_dev dev,
 311                        const struct blkid_magic *id __BLKID_ATTR((unused)),
 312                        unsigned char *buf)
 313 {
 314         struct cramfs_super_block *csb;
 315         const char *label = 0;
 316
 317         csb = (struct cramfs_super_block *)buf;
 318
 319         if (strlen((char *) csb->name))
 320                 label = (char *) csb->name;
 321         blkid_set_tag(dev, "LABEL", label, 0);
 322         return 0;
 323 }
 324
 325 static int probe_swap0(int fd __BLKID_ATTR((unused)),
 326                        blkid_cache cache __BLKID_ATTR((unused)),
 327                        blkid_dev dev,
 328                        const struct blkid_magic *id __BLKID_ATTR((unused)),
 329                        unsigned char *buf __BLKID_ATTR((unused)))
 330 {
 331         blkid_set_tag(dev, "UUID", 0, 0);
 332         blkid_set_tag(dev, "LABEL", 0, 0);
 333         return 0;
 334 }
 335
 336 static int probe_swap1(int fd,
 337                        blkid_cache cache __BLKID_ATTR((unused)),
 338                        blkid_dev dev,
 339                        const struct blkid_magic *id __BLKID_ATTR((unused)),
 340                        unsigned char *buf __BLKID_ATTR((unused)))
 341 {
 342         struct swap_id_block *sws;
 343
 344         probe_swap0(fd, cache, dev, id, buf);
 345         /*
 346          * Version 1 swap headers are always located at offset of 1024
 347          * bytes, although the swap signature itself is located at the
 348          * end of the page (which may vary depending on hardware
 349          * pagesize).
 350          */
 351         if (lseek(fd, 1024, SEEK_SET) < 0) return 1;
 352         sws = xmalloc(1024);
 353         if (read(fd, sws, 1024) != 1024) {
 354                 free(sws);
 355                 return 1;
 356         }
 357
 358         /* arbitrary sanity check.. is there any garbage down there? */
 359         if (sws->sws_pad[32] == 0 && sws->sws_pad[33] == 0)  {
 360                 if (sws->sws_volume[0])
 361                         blkid_set_tag(dev, "LABEL", (const char*)sws->sws_volume,
 362                                       sizeof(sws->sws_volume));
 363                 if (sws->sws_uuid[0])
 364                         set_uuid(dev, sws->sws_uuid);
 365         }
 366         free(sws);
 367
 368         return 0;
 369 }
 370
 371 static const char
 372 * const udf_magic[] = { "BEA01", "BOOT2", "CD001", "CDW02", "NSR02",
 373                  "NSR03", "TEA01", 0 };
 374
 375 static int probe_udf(int fd, blkid_cache cache __BLKID_ATTR((unused)),
 376                      blkid_dev dev __BLKID_ATTR((unused)),
 377                      const struct blkid_magic *id __BLKID_ATTR((unused)),
 378                      unsigned char *buf __BLKID_ATTR((unused)))
 379 {
 380         int j, bs;
 381         struct iso_volume_descriptor isosb;
 382         const char *const *m;
 383
 384         /* determine the block size by scanning in 2K increments
 385            (block sizes larger than 2K will be null padded) */
 386         for (bs = 1; bs < 16; bs++) {
 387                 lseek(fd, bs*2048+32768, SEEK_SET);
 388                 if (read(fd, (char *)&isosb, sizeof(isosb)) != sizeof(isosb))
 389                         return 1;
 390                 if (isosb.id[0])
 391                         break;
 392         }
 393
 394         /* Scan up to another 64 blocks looking for additional VSD's */
 395         for (j = 1; j < 64; j++) {
 396                 if (j > 1) {
 397                         lseek(fd, j*bs*2048+32768, SEEK_SET);
 398                         if (read(fd, (char *)&isosb, sizeof(isosb))
 399                             != sizeof(isosb))
 400                                 return 1;
 401                 }
 402                 /* If we find NSR0x then call it udf:
 403                    NSR01 for UDF 1.00
 404                    NSR02 for UDF 1.50
 405                    NSR03 for UDF 2.00 */
 406                 if (!strncmp(isosb.id, "NSR0", 4))
 407                         return 0;
 408                 for (m = udf_magic; *m; m++)
 409                         if (!strncmp(*m, isosb.id, 5))
 410                                 break;
 411                 if (*m == 0)
 412                         return 1;
 413         }
 414         return 1;
 415 }
 416
 417 static int probe_ocfs(int fd __BLKID_ATTR((unused)),
 418                       blkid_cache cache __BLKID_ATTR((unused)),
 419                       blkid_dev dev,
 420                       const struct blkid_magic *id __BLKID_ATTR((unused)),
 421                       unsigned char *buf)
 422 {
 423         struct ocfs_volume_header ovh;
 424         struct ocfs_volume_label ovl;
 425         __u32 major;
 426
 427         memcpy(&ovh, buf, sizeof(ovh));
 428         memcpy(&ovl, buf+512, sizeof(ovl));
 429
 430         major = ocfsmajor(ovh);
 431         if (major == 1)
 432                 blkid_set_tag(dev,"SEC_TYPE","ocfs1",sizeof("ocfs1"));
 433         else if (major >= 9)
 434                 blkid_set_tag(dev,"SEC_TYPE","ntocfs",sizeof("ntocfs"));
 435
 436         blkid_set_tag(dev, "LABEL", (const char*)ovl.label, ocfslabellen(ovl));
 437         blkid_set_tag(dev, "MOUNT", (const char*)ovh.mount, ocfsmountlen(ovh));
 438         set_uuid(dev, ovl.vol_id);
 439         return 0;
 440 }
 441
 442 static int probe_ocfs2(int fd __BLKID_ATTR((unused)),
 443                        blkid_cache cache __BLKID_ATTR((unused)),
 444                        blkid_dev dev,
 445                        const struct blkid_magic *id __BLKID_ATTR((unused)),
 446                        unsigned char *buf)
 447 {
 448         struct ocfs2_super_block *osb;
 449
 450         osb = (struct ocfs2_super_block *)buf;
 451
 452         blkid_set_tag(dev, "LABEL", (const char*)osb->s_label, sizeof(osb->s_label));
 453         set_uuid(dev, osb->s_uuid);
 454         return 0;
 455 }
 456
 457 static int probe_oracleasm(int fd __BLKID_ATTR((unused)),
 458                            blkid_cache cache __BLKID_ATTR((unused)),
 459                            blkid_dev dev,
 460                            const struct blkid_magic *id __BLKID_ATTR((unused)),
 461                            unsigned char *buf)
 462 {
 463         struct oracle_asm_disk_label *dl;
 464
 465         dl = (struct oracle_asm_disk_label *)buf;
 466
 467         blkid_set_tag(dev, "LABEL", dl->dl_id, sizeof(dl->dl_id));
 468         return 0;
 469 }
 470
 471 /*
 472  * BLKID_BLK_OFFS is at least as large as the highest bim_kboff defined
 473  * in the type_array table below + bim_kbalign.
 474  *
 475  * When probing for a lot of magics, we handle everything in 1kB buffers so
 476  * that we don't have to worry about reading each combination of block sizes.
 477  */
 478 #define BLKID_BLK_OFFS  64      /* currently reiserfs */
 479
 480 /*
 481  * Various filesystem magics that we can check for.  Note that kboff and
 482  * sboff are in kilobytes and bytes respectively.  All magics are in
 483  * byte strings so we don't worry about endian issues.
 484  */
 485 static const struct blkid_magic type_array[] = {
 486 /*  type     kboff   sboff len  magic                   probe */
 487   { "oracleasm", 0,     32,  8, "ORCLDISK",             probe_oracleasm },
 488   { "ntfs",      0,      3,  8, "NTFS    ",             0 },
 489   { "jbd",       1,   0x38,  2, "\123\357",             probe_jbd },
 490   { "ext3",      1,   0x38,  2, "\123\357",             probe_ext3 },
 491   { "ext2",      1,   0x38,  2, "\123\357",             probe_ext2 },
 492   { "reiserfs",  8,   0x34,  8, "ReIsErFs",             probe_reiserfs },
 493   { "reiserfs", 64,   0x34,  9, "ReIsEr2Fs",            probe_reiserfs },
 494   { "reiserfs", 64,   0x34,  9, "ReIsEr3Fs",            probe_reiserfs },
 495   { "reiserfs", 64,   0x34,  8, "ReIsErFs",             probe_reiserfs },
 496   { "reiserfs",  8,     20,  8, "ReIsErFs",             probe_reiserfs },
 497   { "vfat",      0,   0x52,  5, "MSWIN",                probe_vfat },
 498   { "vfat",      0,   0x52,  8, "FAT32   ",             probe_vfat },
 499   { "vfat",      0,   0x36,  5, "MSDOS",                probe_msdos },
 500   { "vfat",      0,   0x36,  8, "FAT16   ",             probe_msdos },
 501   { "vfat",      0,   0x36,  8, "FAT12   ",             probe_msdos },
 502   { "minix",     1,   0x10,  2, "\177\023",             0 },
 503   { "minix",     1,   0x10,  2, "\217\023",             0 },
 504   { "minix",     1,   0x10,  2, "\150\044",             0 },
 505   { "minix",     1,   0x10,  2, "\170\044",             0 },
 506   { "vxfs",      1,      0,  4, "\365\374\001\245",     0 },
 507   { "xfs",       0,      0,  4, "XFSB",                 probe_xfs },
 508   { "romfs",     0,      0,  8, "-rom1fs-",             probe_romfs },
 509   { "bfs",       0,      0,  4, "\316\372\173\033",     0 },
 510   { "cramfs",    0,      0,  4, "E=\315\050",           probe_cramfs },
 511   { "qnx4",      0,      4,  6, "QNX4FS",               0 },
 512   { "udf",      32,      1,  5, "BEA01",                probe_udf },
 513   { "udf",      32,      1,  5, "BOOT2",                probe_udf },
 514   { "udf",      32,      1,  5, "CD001",                probe_udf },
 515   { "udf",      32,      1,  5, "CDW02",                probe_udf },
 516   { "udf",      32,      1,  5, "NSR02",                probe_udf },
 517   { "udf",      32,      1,  5, "NSR03",                probe_udf },
 518   { "udf",      32,      1,  5, "TEA01",                probe_udf },
 519   { "iso9660",  32,      1,  5, "CD001",                0 },
 520   { "iso9660",  32,      9,  5, "CDROM",                0 },
 521   { "jfs",      32,      0,  4, "JFS1",                 probe_jfs },
 522   { "hfs",       1,      0,  2, "BD",                   0 },
 523   { "ufs",       8,  0x55c,  4, "T\031\001\000",        0 },
 524   { "hpfs",      8,      0,  4, "I\350\225\371",        0 },
 525   { "sysv",      0,  0x3f8,  4, "\020~\030\375",        0 },
 526   { "swap",      0,  0xff6, 10, "SWAP-SPACE",           probe_swap0 },
 527   { "swap",      0,  0xff6, 10, "SWAPSPACE2",           probe_swap1 },
 528   { "swap",      0, 0x1ff6, 10, "SWAP-SPACE",           probe_swap0 },
 529   { "swap",      0, 0x1ff6, 10, "SWAPSPACE2",           probe_swap1 },
 530   { "swap",      0, 0x3ff6, 10, "SWAP-SPACE",           probe_swap0 },
 531   { "swap",      0, 0x3ff6, 10, "SWAPSPACE2",           probe_swap1 },
 532   { "swap",      0, 0x7ff6, 10, "SWAP-SPACE",           probe_swap0 },
 533   { "swap",      0, 0x7ff6, 10, "SWAPSPACE2",           probe_swap1 },
 534   { "swap",      0, 0xfff6, 10, "SWAP-SPACE",           probe_swap0 },
 535   { "swap",      0, 0xfff6, 10, "SWAPSPACE2",           probe_swap1 },
 536   { "ocfs",      0,      8,  9, "OracleCFS",            probe_ocfs },
 537   { "ocfs2",     1,      0,  6, "OCFSV2",               probe_ocfs2 },
 538   { "ocfs2",     2,      0,  6, "OCFSV2",               probe_ocfs2 },
 539   { "ocfs2",     4,      0,  6, "OCFSV2",               probe_ocfs2 },
 540   { "ocfs2",     8,      0,  6, "OCFSV2",               probe_ocfs2 },
 541   {   NULL,      0,      0,  0, NULL,                   NULL }
 542 };
 543
 544 /*
 545  * Verify that the data in dev is consistent with what is on the actual
 546  * block device (using the devname field only).  Normally this will be
 547  * called when finding items in the cache, but for long running processes
 548  * is also desirable to revalidate an item before use.
 549  *
 550  * If we are unable to revalidate the data, we return the old data and
 551  * do not set the BLKID_BID_FL_VERIFIED flag on it.
 552  */
 553 blkid_dev blkid_verify(blkid_cache cache, blkid_dev dev)
 554 {
 555         const struct blkid_magic *id;
 556         unsigned char *bufs[BLKID_BLK_OFFS + 1], *buf;
 557         const char *type;
 558         struct stat st;
 559         time_t diff, now;
 560         int fd, idx;
 561
 562         if (!dev)
 563                 return NULL;
 564
 565         now = time(0);
 566         diff = now - dev->bid_time;
 567
 568         if ((now < dev->bid_time) ||
 569             (diff < BLKID_PROBE_MIN) ||
 570             (dev->bid_flags & BLKID_BID_FL_VERIFIED &&
 571              diff < BLKID_PROBE_INTERVAL))
 572                 return dev;
 573
 574         DBG(DEBUG_PROBE,
 575             printf("need to revalidate %s (time since last check %lu)\n",
 576                    dev->bid_name, diff));
 577
 578         if (((fd = open(dev->bid_name, O_RDONLY)) < 0) ||
 579             (fstat(fd, &st) < 0)) {
 580                 if (errno == ENXIO || errno == ENODEV || errno == ENOENT) {
 581                         blkid_free_dev(dev);
 582                         return NULL;
 583                 }
 584                 /* We don't have read permission, just return cache data. */
 585                 DBG(DEBUG_PROBE,
 586                     printf("returning unverified data for %s\n",
 587                            dev->bid_name));
 588                 return dev;
 589         }
 590
 591         memset(bufs, 0, sizeof(bufs));
 592
 593         /*
 594          * Iterate over the type array.  If we already know the type,
 595          * then try that first.  If it doesn't work, then blow away
 596          * the type information, and try again.
 597          *
 598          */
 599 try_again:
 600         type = 0;
 601         if (!dev->bid_type || !strcmp(dev->bid_type, "mdraid")) {
 602                 uuid_t  uuid;
 603
 604                 if (check_mdraid(fd, uuid) == 0) {
 605                         set_uuid(dev, uuid);
 606                         type = "mdraid";
 607                         goto found_type;
 608                 }
 609         }
 610         for (id = type_array; id->bim_type; id++) {
 611                 if (dev->bid_type &&
 612                     strcmp(id->bim_type, dev->bid_type))
 613                         continue;
 614
 615                 idx = id->bim_kboff + (id->bim_sboff >> 10);
 616                 if (idx > BLKID_BLK_OFFS || idx < 0)
 617                         continue;
 618                 buf = bufs[idx];
 619                 if (!buf) {
 620                         if (lseek(fd, idx << 10, SEEK_SET) < 0)
 621                                 continue;
 622
 623                         buf = xmalloc(1024);
 624
 625                         if (read(fd, buf, 1024) != 1024) {
 626                                 free(buf);
 627                                 continue;
 628                         }
 629                         bufs[idx] = buf;
 630                 }
 631
 632                 if (memcmp(id->bim_magic, buf + (id->bim_sboff&0x3ff),
 633                            id->bim_len))
 634                         continue;
 635
 636                 if ((id->bim_probe == NULL) ||
 637                     (id->bim_probe(fd, cache, dev, id, buf) == 0)) {
 638                         type = id->bim_type;
 639                         goto found_type;
 640                 }
 641         }
 642
 643         if (!id->bim_type && dev->bid_type) {
 644                 /*
 645                  * Zap the device filesystem type and try again
 646                  */
 647                 blkid_set_tag(dev, "TYPE", 0, 0);
 648                 blkid_set_tag(dev, "SEC_TYPE", 0, 0);
 649                 blkid_set_tag(dev, "LABEL", 0, 0);
 650                 blkid_set_tag(dev, "UUID", 0, 0);
 651                 goto try_again;
 652         }
 653
 654         if (!dev->bid_type) {
 655                 blkid_free_dev(dev);
 656                 return NULL;
 657         }
 658
 659 found_type:
 660         if (dev && type) {
 661                 dev->bid_devno = st.st_rdev;
 662                 dev->bid_time = time(0);
 663                 dev->bid_flags |= BLKID_BID_FL_VERIFIED;
 664                 cache->bic_flags |= BLKID_BIC_FL_CHANGED;
 665
 666                 blkid_set_tag(dev, "TYPE", type, 0);
 667
 668                 DBG(DEBUG_PROBE, printf("%s: devno 0x%04llx, type %s\n",
 669                            dev->bid_name, st.st_rdev, type));
 670         }
 671
 672         close(fd);
 673
 674         return dev;
 675 }
 676
 677 int blkid_known_fstype(const char *fstype)
 678 {
 679         const struct blkid_magic *id;
 680
 681         for (id = type_array; id->bim_type; id++) {
 682                 if (strcmp(fstype, id->bim_type) == 0)
 683                         return 1;
 684         }
 685         return 0;
 686 }
 687
 688 #ifdef TEST_PROGRAM
 689 int main(int argc, char **argv)
 690 {
 691         blkid_dev dev;
 692         blkid_cache cache;
 693         int ret;
 694
 695         blkid_debug_mask = DEBUG_ALL;
 696         if (argc != 2) {
 697                 fprintf(stderr, "Usage: %s device\n"
 698                         "Probe a single device to determine type\n", argv[0]);
 699                 exit(1);
 700         }
 701         if ((ret = blkid_get_cache(&cache, bb_dev_null)) != 0) {
 702                 fprintf(stderr, "%s: error creating cache (%d)\n",
 703                         argv[0], ret);
 704                 exit(1);
 705         }
 706         dev = blkid_get_dev(cache, argv[1], BLKID_DEV_NORMAL);
 707         if (!dev) {
 708                 printf("%s: %s has an unsupported type\n", argv[0], argv[1]);
 709                 return 1;
 710         }
 711         printf("%s is type %s\n", argv[1], dev->bid_type ?
 712                 dev->bid_type : "(null)");
 713         if (dev->bid_label)
 714                 printf("\tlabel is '%s'\n", dev->bid_label);
 715         if (dev->bid_uuid)
 716                 printf("\tuuid is %s\n", dev->bid_uuid);
 717
 718         blkid_free_dev(dev);
 719         return 0;
 720 }
 721 #endif