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