lib/blkid/devname.c

   1 /*
   2  * devname.c - get a dev by its device inode name
   3  *
   4  * Copyright (C) Andries Brouwer
   5  * Copyright (C) 1999, 2000, 2001, 2002, 2003 Theodore Ts'o
   6  * Copyright (C) 2001 Andreas Dilger
   7  *
   8  * %Begin-Header%
   9  * This file may be redistributed under the terms of the
  10  * GNU Lesser General Public License.
  11  * %End-Header%
  12  */
  13
  14 #define _GNU_SOURCE 1
  15
  16 #include <stdio.h>
  17 #include <string.h>
  18 #include <limits.h>
  19 #if HAVE_UNISTD_H
  20 #include <unistd.h>
  21 #endif
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <ctype.h>
  25 #if HAVE_SYS_TYPES_H
  26 #include <sys/types.h>
  27 #endif
  28 #if HAVE_SYS_STAT_H
  29 #include <sys/stat.h>
  30 #endif
  31 #if HAVE_ERRNO_H
  32 #include <errno.h>
  33 #endif
  34 #if HAVE_SYS_MKDEV_H
  35 #include <sys/mkdev.h>
  36 #endif
  37 #include <time.h>
  38
  39 #include "blkidP.h"
  40
  41 #ifdef HAVE_DEVMAPPER
  42 #include <libdevmapper.h>
  43 #endif
  44
  45 /*
  46  * Find a dev struct in the cache by device name, if available.
  47  *
  48  * If there is no entry with the specified device name, and the create
  49  * flag is set, then create an empty device entry.
  50  */
  51 blkid_dev blkid_get_dev(blkid_cache cache, const char *devname, int flags)
  52 {
  53         blkid_dev dev = NULL, tmp;
  54         struct list_head *p, *pnext;
  55
  56         if (!cache || !devname)
  57                 return NULL;
  58
  59         list_for_each(p, &cache->bic_devs) {
  60                 tmp = list_entry(p, struct blkid_struct_dev, bid_devs);
  61                 if (strcmp(tmp->bid_name, devname))
  62                         continue;
  63
  64                 DBG(DEBUG_DEVNAME,
  65                     printf("found devname %s in cache\n", tmp->bid_name));
  66                 dev = tmp;
  67                 break;
  68         }
  69
  70         if (!dev && (flags & BLKID_DEV_CREATE)) {
  71                 dev = blkid_new_dev();
  72                 if (!dev)
  73                         return NULL;
  74                 dev->bid_time = INT_MIN;
  75                 dev->bid_name = blkid_strdup(devname);
  76                 dev->bid_cache = cache;
  77                 list_add_tail(&dev->bid_devs, &cache->bic_devs);
  78                 cache->bic_flags |= BLKID_BIC_FL_CHANGED;
  79         }
  80
  81         if (flags & BLKID_DEV_VERIFY) {
  82                 dev = blkid_verify(cache, dev);
  83                 if (!dev || !(dev->bid_flags & BLKID_BID_FL_VERIFIED))
  84                         return dev;
  85                 /*
  86                  * If the device is verified, then search the blkid
  87                  * cache for any entries that match on the type, uuid,
  88                  * and label, and verify them; if a cache entry can
  89                  * not be verified, then it's stale and so we remove
  90                  * it.
  91                  */
  92                 list_for_each_safe(p, pnext, &cache->bic_devs) {
  93                         blkid_dev dev2;
  94                         if (!p)
  95                                 break;
  96                         dev2 = list_entry(p, struct blkid_struct_dev, bid_devs);
  97                         if (dev2->bid_flags & BLKID_BID_FL_VERIFIED)
  98                                 continue;
  99                         if (strcmp(dev->bid_type, dev2->bid_type))
 100                                 continue;
 101                         if (dev->bid_label && dev2->bid_label &&
 102                             strcmp(dev->bid_label, dev2->bid_label))
 103                                 continue;
 104                         if (dev->bid_uuid && dev2->bid_uuid &&
 105                             strcmp(dev->bid_uuid, dev2->bid_uuid))
 106                                 continue;
 107                         if ((dev->bid_label && !dev2->bid_label) ||
 108                             (!dev->bid_label && dev2->bid_label) ||
 109                             (dev->bid_uuid && !dev2->bid_uuid) ||
 110                             (!dev->bid_uuid && dev2->bid_uuid))
 111                                 continue;
 112                         dev2 = blkid_verify(cache, dev2);
 113                         if (dev2 && !(dev2->bid_flags & BLKID_BID_FL_VERIFIED))
 114                                 blkid_free_dev(dev2);
 115                 }
 116         }
 117         return dev;
 118 }
 119
 120 #ifdef HAVE_DEVMAPPER
 121 static int dm_device_is_leaf(const dev_t dev);
 122 #endif
 123
 124 /*
 125  * Probe a single block device to add to the device cache.
 126  */
 127 static void probe_one(blkid_cache cache, const char *ptname,
 128                       dev_t devno, int pri, int only_if_new)
 129 {
 130         blkid_dev dev = NULL;
 131         struct list_head *p;
 132         const char **dir;
 133         char *devname = NULL;
 134
 135         /* See if we already have this device number in the cache. */
 136         list_for_each(p, &cache->bic_devs) {
 137                 blkid_dev tmp = list_entry(p, struct blkid_struct_dev,
 138                                            bid_devs);
 139 #ifdef HAVE_DEVMAPPER
 140                 if (!dm_device_is_leaf(devno))
 141                         continue;
 142 #endif
 143                 if (tmp->bid_devno == devno) {
 144                         if (only_if_new)
 145                                 return;
 146                         dev = blkid_verify(cache, tmp);
 147                         break;
 148                 }
 149         }
 150         if (dev && dev->bid_devno == devno)
 151                 goto set_pri;
 152
 153         /*
 154          * Take a quick look at /dev/ptname for the device number.  We check
 155          * all of the likely device directories.  If we don't find it, or if
 156          * the stat information doesn't check out, use blkid_devno_to_devname()
 157          * to find it via an exhaustive search for the device major/minor.
 158          */
 159         for (dir = blkid_devdirs; *dir; dir++) {
 160                 struct stat st;
 161                 char device[256];
 162
 163                 sprintf(device, "%s/%s", *dir, ptname);
 164                 if ((dev = blkid_get_dev(cache, device, BLKID_DEV_FIND)) &&
 165                     dev->bid_devno == devno)
 166                         goto set_pri;
 167
 168                 if (stat(device, &st) == 0 && S_ISBLK(st.st_mode) &&
 169                     st.st_rdev == devno) {
 170                         devname = blkid_strdup(device);
 171                         break;
 172                 }
 173         }
 174         if (!devname) {
 175                 devname = blkid_devno_to_devname(devno);
 176                 if (!devname)
 177                         return;
 178         }
 179         dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
 180         free(devname);
 181
 182 set_pri:
 183         if (!pri && !strncmp(ptname, "md", 2))
 184                 pri = BLKID_PRI_MD;
 185         if (dev)
 186                 dev->bid_pri = pri;
 187         return;
 188 }
 189
 190 #ifdef HAVE_DEVMAPPER
 191 static void dm_quiet_log(int level __BLKID_ATTR((unused)),
 192                          const char *file __BLKID_ATTR((unused)),
 193                          int line __BLKID_ATTR((unused)),
 194                          const char *f __BLKID_ATTR((unused)), ...)
 195 {
 196         return;
 197 }
 198
 199 /*
 200  * device-mapper support
 201  */
 202 static int dm_device_has_dep(const dev_t dev, const char *name)
 203 {
 204         struct dm_task *task;
 205         struct dm_deps *deps;
 206         struct dm_info info;
 207         unsigned int i;
 208         int ret = 0;
 209
 210         task = dm_task_create(DM_DEVICE_DEPS);
 211         if (!task)
 212                 goto out;
 213
 214         if (!dm_task_set_name(task, name))
 215                 goto out;
 216
 217         if (!dm_task_run(task))
 218                 goto out;
 219
 220         if (!dm_task_get_info(task, &info))
 221                 goto out;
 222
 223         if  (!info.exists)
 224                 goto out;
 225
 226         deps = dm_task_get_deps(task);
 227         if (!deps || deps->count == 0)
 228                 goto out;
 229
 230         for (i = 0; i < deps->count; i++) {
 231                 dev_t dep_dev = deps->device[i];
 232
 233                 if (dev == dep_dev) {
 234                         ret = 1;
 235                         goto out;
 236                 }
 237         }
 238
 239 out:
 240         if (task)
 241                 dm_task_destroy(task);
 242
 243         return ret;
 244 }
 245
 246 static int dm_device_is_leaf(const dev_t dev)
 247 {
 248         struct dm_task *task;
 249         struct dm_names *names;
 250         unsigned int next = 0;
 251         int n, ret = 1;
 252
 253         dm_log_init(dm_quiet_log);
 254         task = dm_task_create(DM_DEVICE_LIST);
 255         if (!task)
 256                 goto out;
 257
 258         dm_log_init(0);
 259
 260         if (!dm_task_run(task))
 261                 goto out;
 262
 263         names = dm_task_get_names(task);
 264         if (!names || !names->dev)
 265                 goto out;
 266
 267         n = 0;
 268         do {
 269                 names = (struct dm_names *) ((char *)names + next);
 270
 271                 if (dm_device_has_dep(dev, names->name))
 272                         ret = 0;
 273
 274                 next = names->next;
 275         } while (next);
 276
 277 out:
 278         if (task)
 279                 dm_task_destroy(task);
 280
 281         return ret;
 282 }
 283
 284 static dev_t dm_get_devno(const char *name)
 285 {
 286         struct dm_task *task;
 287         struct dm_info info;
 288         dev_t ret = 0;
 289
 290         task = dm_task_create(DM_DEVICE_INFO);
 291         if (!task)
 292                 goto out;
 293
 294         if (!dm_task_set_name(task, name))
 295                 goto out;
 296
 297         if (!dm_task_run(task))
 298                 goto out;
 299
 300         if (!dm_task_get_info(task, &info))
 301                 goto out;
 302
 303         if (!info.exists)
 304                 goto out;
 305
 306         ret = makedev(info.major, info.minor);
 307
 308 out:
 309         if (task)
 310                 dm_task_destroy(task);
 311
 312         return ret;
 313 }
 314
 315 static void dm_probe_all(blkid_cache cache, int only_if_new)
 316 {
 317         struct dm_task *task;
 318         struct dm_names *names;
 319         unsigned int next = 0;
 320         int n;
 321
 322         dm_log_init(dm_quiet_log);
 323         task = dm_task_create(DM_DEVICE_LIST);
 324         if (!task)
 325                 goto out;
 326         dm_log_init(0);
 327
 328         if (!dm_task_run(task))
 329                 goto out;
 330
 331         names = dm_task_get_names(task);
 332         if (!names || !names->dev)
 333                 goto out;
 334
 335         n = 0;
 336         do {
 337                 int rc;
 338                 char *device = NULL;
 339                 dev_t dev = 0;
 340
 341                 names = (struct dm_names *) ((char *)names + next);
 342
 343                 rc = asprintf(&device, "mapper/%s", names->name);
 344                 if (rc < 0)
 345                         goto try_next;
 346
 347                 dev = dm_get_devno(names->name);
 348                 if (dev == 0)
 349                         goto try_next;
 350
 351                 if (!dm_device_is_leaf(dev))
 352                         goto try_next;
 353
 354                 probe_one(cache, device, dev, BLKID_PRI_DM, only_if_new);
 355
 356 try_next:
 357                 free(device);
 358                 next = names->next;
 359         } while (next);
 360
 361 out:
 362         if (task)
 363                 dm_task_destroy(task);
 364 }
 365 #endif /* HAVE_DEVMAPPER */
 366
 367 #define PROC_PARTITIONS "/proc/partitions"
 368 #define VG_DIR          "/proc/lvm/VGs"
 369
 370 /*
 371  * This function initializes the UUID cache with devices from the LVM
 372  * proc hierarchy.  We currently depend on the names of the LVM
 373  * hierarchy giving us the device structure in /dev.  (XXX is this a
 374  * safe thing to do?)
 375  */
 376 #ifdef VG_DIR
 377 #include <dirent.h>
 378 static dev_t lvm_get_devno(const char *lvm_device)
 379 {
 380         FILE *lvf;
 381         char buf[1024];
 382         int ma, mi;
 383         dev_t ret = 0;
 384
 385         DBG(DEBUG_DEVNAME, printf("opening %s\n", lvm_device));
 386         if ((lvf = fopen(lvm_device, "r")) == NULL) {
 387                 DBG(DEBUG_DEVNAME, printf("%s: (%d) %s\n", lvm_device, errno,
 388                                           strerror(errno)));
 389                 return 0;
 390         }
 391
 392         while (fgets(buf, sizeof(buf), lvf)) {
 393                 if (sscanf(buf, "device: %d:%d", &ma, &mi) == 2) {
 394                         ret = makedev(ma, mi);
 395                         break;
 396                 }
 397         }
 398         fclose(lvf);
 399
 400         return ret;
 401 }
 402
 403 static void lvm_probe_all(blkid_cache cache, int only_if_new)
 404 {
 405         DIR             *vg_list;
 406         struct dirent   *vg_iter;
 407         int             vg_len = strlen(VG_DIR);
 408         dev_t           dev;
 409
 410         if ((vg_list = opendir(VG_DIR)) == NULL)
 411                 return;
 412
 413         DBG(DEBUG_DEVNAME, printf("probing LVM devices under %s\n", VG_DIR));
 414
 415         while ((vg_iter = readdir(vg_list)) != NULL) {
 416                 DIR             *lv_list;
 417                 char            *vdirname;
 418                 char            *vg_name;
 419                 struct dirent   *lv_iter;
 420
 421                 vg_name = vg_iter->d_name;
 422                 if (!strcmp(vg_name, ".") || !strcmp(vg_name, ".."))
 423                         continue;
 424                 vdirname = malloc(vg_len + strlen(vg_name) + 8);
 425                 if (!vdirname)
 426                         goto exit;
 427                 sprintf(vdirname, "%s/%s/LVs", VG_DIR, vg_name);
 428
 429                 lv_list = opendir(vdirname);
 430                 free(vdirname);
 431                 if (lv_list == NULL)
 432                         continue;
 433
 434                 while ((lv_iter = readdir(lv_list)) != NULL) {
 435                         char            *lv_name, *lvm_device;
 436
 437                         lv_name = lv_iter->d_name;
 438                         if (!strcmp(lv_name, ".") || !strcmp(lv_name, ".."))
 439                                 continue;
 440
 441                         lvm_device = malloc(vg_len + strlen(vg_name) +
 442                                             strlen(lv_name) + 8);
 443                         if (!lvm_device) {
 444                                 closedir(lv_list);
 445                                 goto exit;
 446                         }
 447                         sprintf(lvm_device, "%s/%s/LVs/%s", VG_DIR, vg_name,
 448                                 lv_name);
 449                         dev = lvm_get_devno(lvm_device);
 450                         sprintf(lvm_device, "%s/%s", vg_name, lv_name);
 451                         DBG(DEBUG_DEVNAME, printf("LVM dev %s: devno 0x%04X\n",
 452                                                   lvm_device,
 453                                                   (unsigned int) dev));
 454                         probe_one(cache, lvm_device, dev, BLKID_PRI_LVM,
 455                                   only_if_new);
 456                         free(lvm_device);
 457                 }
 458                 closedir(lv_list);
 459         }
 460 exit:
 461         closedir(vg_list);
 462 }
 463 #endif
 464
 465 #define PROC_EVMS_VOLUMES "/proc/evms/volumes"
 466
 467 static int
 468 evms_probe_all(blkid_cache cache, int only_if_new)
 469 {
 470         char line[100];
 471         int ma, mi, sz, num = 0;
 472         FILE *procpt;
 473         char device[110];
 474
 475         procpt = fopen(PROC_EVMS_VOLUMES, "r");
 476         if (!procpt)
 477                 return 0;
 478         while (fgets(line, sizeof(line), procpt)) {
 479                 if (sscanf (line, " %d %d %d %*s %*s %[^\n ]",
 480                             &ma, &mi, &sz, device) != 4)
 481                         continue;
 482
 483                 DBG(DEBUG_DEVNAME, printf("Checking partition %s (%d, %d)\n",
 484                                           device, ma, mi));
 485
 486                 probe_one(cache, device, makedev(ma, mi), BLKID_PRI_EVMS,
 487                           only_if_new);
 488                 num++;
 489         }
 490         fclose(procpt);
 491         return num;
 492 }
 493
 494 /*
 495  * Read the device data for all available block devices in the system.
 496  */
 497 static int probe_all(blkid_cache cache, int only_if_new)
 498 {
 499         FILE *proc;
 500         char line[1024];
 501         char ptname0[128], ptname1[128], *ptname = 0;
 502         char *ptnames[2];
 503         dev_t devs[2];
 504         int ma, mi;
 505         unsigned long long sz;
 506         int lens[2] = { 0, 0 };
 507         int which = 0, last = 0;
 508
 509         ptnames[0] = ptname0;
 510         ptnames[1] = ptname1;
 511
 512         if (!cache)
 513                 return -BLKID_ERR_PARAM;
 514
 515         if (cache->bic_flags & BLKID_BIC_FL_PROBED &&
 516             time(0) - cache->bic_time < BLKID_PROBE_INTERVAL)
 517                 return 0;
 518
 519         blkid_read_cache(cache);
 520 #ifdef HAVE_DEVMAPPER
 521         dm_probe_all(cache, only_if_new);
 522 #endif
 523         evms_probe_all(cache, only_if_new);
 524 #ifdef VG_DIR
 525         lvm_probe_all(cache, only_if_new);
 526 #endif
 527
 528         proc = fopen(PROC_PARTITIONS, "r");
 529         if (!proc)
 530                 return -BLKID_ERR_PROC;
 531
 532         while (fgets(line, sizeof(line), proc)) {
 533                 last = which;
 534                 which ^= 1;
 535                 ptname = ptnames[which];
 536
 537                 if (sscanf(line, " %d %d %llu %128[^\n ]",
 538                            &ma, &mi, &sz, ptname) != 4)
 539                         continue;
 540                 devs[which] = makedev(ma, mi);
 541
 542                 DBG(DEBUG_DEVNAME, printf("read partition name %s\n", ptname));
 543
 544                 /* Skip whole disk devs unless they have no partitions.
 545                  * If base name of device has changed, also
 546                  * check previous dev to see if it didn't have a partn.
 547                  * heuristic: partition name ends in a digit, & partition
 548                  * names contain whole device name as substring.
 549                  *
 550                  * Skip extended partitions.
 551                  * heuristic: size is 1
 552                  *
 553                  * FIXME: skip /dev/{ida,cciss,rd} whole-disk devs
 554                  */
 555
 556                 lens[which] = strlen(ptname);
 557
 558                 /* ends in a digit, clearly a partition, so check */
 559                 if (isdigit(ptname[lens[which] - 1])) {
 560                         DBG(DEBUG_DEVNAME,
 561                             printf("partition dev %s, devno 0x%04X\n",
 562                                    ptname, (unsigned int) devs[which]));
 563
 564                         if (sz > 1)
 565                                 probe_one(cache, ptname, devs[which], 0,
 566                                           only_if_new);
 567                         lens[which] = 0;        /* mark as checked */
 568                 }
 569
 570                 /*
 571                  * If last was not checked because it looked like a whole-disk
 572                  * dev, and the device's base name has changed,
 573                  * check last as well.
 574                  */
 575                 if (lens[last] && strncmp(ptnames[last], ptname, lens[last])) {
 576                         DBG(DEBUG_DEVNAME,
 577                             printf("whole dev %s, devno 0x%04X\n",
 578                                    ptnames[last], (unsigned int) devs[last]));
 579                         probe_one(cache, ptnames[last], devs[last], 0,
 580                                   only_if_new);
 581                         lens[last] = 0;
 582                 }
 583         }
 584
 585         /* Handle the last device if it wasn't partitioned */
 586         if (lens[which])
 587                 probe_one(cache, ptname, devs[which], 0, only_if_new);
 588
 589         fclose(proc);
 590         blkid_flush_cache(cache);
 591         return 0;
 592 }
 593
 594 int blkid_probe_all(blkid_cache cache)
 595 {
 596         int ret;
 597
 598         DBG(DEBUG_PROBE, printf("Begin blkid_probe_all()\n"));
 599         ret = probe_all(cache, 0);
 600         cache->bic_time = time(0);
 601         cache->bic_flags |= BLKID_BIC_FL_PROBED;
 602         DBG(DEBUG_PROBE, printf("End blkid_probe_all()\n"));
 603         return ret;
 604 }
 605
 606 int blkid_probe_all_new(blkid_cache cache)
 607 {
 608         int ret;
 609
 610         DBG(DEBUG_PROBE, printf("Begin blkid_probe_all_new()\n"));
 611         ret = probe_all(cache, 1);
 612         DBG(DEBUG_PROBE, printf("End blkid_probe_all_new()\n"));
 613         return ret;
 614 }
 615
 616
 617 #ifdef TEST_PROGRAM
 618 int main(int argc, char **argv)
 619 {
 620         blkid_cache cache = NULL;
 621         int ret;
 622
 623         blkid_debug_mask = DEBUG_ALL;
 624         if (argc != 1) {
 625                 fprintf(stderr, "Usage: %s\n"
 626                         "Probe all devices and exit\n", argv[0]);
 627                 exit(1);
 628         }
 629         if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
 630                 fprintf(stderr, "%s: error creating cache (%d)\n",
 631                         argv[0], ret);
 632                 exit(1);
 633         }
 634         if (blkid_probe_all(cache) < 0)
 635                 printf("%s: error probing devices\n", argv[0]);
 636
 637         blkid_put_cache(cache);
 638         return (0);
 639 }
 640 #endif