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 "config.h"
  17 #include <stdio.h>
  18 #include <string.h>
  19 #include <limits.h>
  20 #if HAVE_UNISTD_H
  21 #include <unistd.h>
  22 #endif
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <ctype.h>
  26 #if HAVE_SYS_TYPES_H
  27 #include <sys/types.h>
  28 #endif
  29 #include <dirent.h>
  30 #if HAVE_SYS_STAT_H
  31 #include <sys/stat.h>
  32 #endif
  33 #if HAVE_ERRNO_H
  34 #include <errno.h>
  35 #endif
  36 #if HAVE_SYS_MKDEV_H
  37 #include <sys/mkdev.h>
  38 #endif
  39 #include <time.h>
  40
  41 #include "blkidP.h"
  42
  43 /*
  44  * Find a dev struct in the cache by device name, if available.
  45  *
  46  * If there is no entry with the specified device name, and the create
  47  * flag is set, then create an empty device entry.
  48  */
  49 blkid_dev blkid_get_dev(blkid_cache cache, const char *devname, int flags)
  50 {
  51         blkid_dev dev = NULL, tmp;
  52         struct list_head *p, *pnext;
  53
  54         if (!cache || !devname)
  55                 return NULL;
  56
  57         list_for_each(p, &cache->bic_devs) {
  58                 tmp = list_entry(p, struct blkid_struct_dev, bid_devs);
  59                 if (strcmp(tmp->bid_name, devname))
  60                         continue;
  61
  62                 DBG(DEBUG_DEVNAME,
  63                     printf("found devname %s in cache\n", tmp->bid_name));
  64                 dev = tmp;
  65                 break;
  66         }
  67
  68         if (!dev && (flags & BLKID_DEV_CREATE)) {
  69                 if (access(devname, F_OK) < 0)
  70                         return NULL;
  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 (!dev->bid_type || !dev2->bid_type ||
 100                             strcmp(dev->bid_type, dev2->bid_type))
 101                                 continue;
 102                         if (dev->bid_label && dev2->bid_label &&
 103                             strcmp(dev->bid_label, dev2->bid_label))
 104                                 continue;
 105                         if (dev->bid_uuid && dev2->bid_uuid &&
 106                             strcmp(dev->bid_uuid, dev2->bid_uuid))
 107                                 continue;
 108                         if ((dev->bid_label && !dev2->bid_label) ||
 109                             (!dev->bid_label && dev2->bid_label) ||
 110                             (dev->bid_uuid && !dev2->bid_uuid) ||
 111                             (!dev->bid_uuid && dev2->bid_uuid))
 112                                 continue;
 113                         dev2 = blkid_verify(cache, dev2);
 114                         if (dev2 && !(dev2->bid_flags & BLKID_BID_FL_VERIFIED))
 115                                 blkid_free_dev(dev2);
 116                 }
 117         }
 118         return dev;
 119 }
 120
 121 /* Directories where we will try to search for device names */
 122 static const char *dirlist[] = { "/dev", "/devfs", "/devices", NULL };
 123
 124 static int is_dm_leaf(const char *devname)
 125 {
 126         struct dirent   *de, *d_de;
 127         DIR             *dir, *d_dir;
 128         char            path[256];
 129         int             ret = 1;
 130
 131         if ((dir = opendir("/sys/block")) == NULL)
 132                 return 0;
 133         while ((de = readdir(dir)) != NULL) {
 134                 if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..") ||
 135                     !strcmp(de->d_name, devname) ||
 136                     strncmp(de->d_name, "dm-", 3) ||
 137                     strlen(de->d_name) > sizeof(path)-32)
 138                         continue;
 139                 sprintf(path, "/sys/block/%s/slaves", de->d_name);
 140                 if ((d_dir = opendir(path)) == NULL)
 141                         continue;
 142                 while ((d_de = readdir(d_dir)) != NULL) {
 143                         if (!strcmp(d_de->d_name, devname)) {
 144                                 ret = 0;
 145                                 break;
 146                         }
 147                 }
 148                 closedir(d_dir);
 149                 if (!ret)
 150                         break;
 151         }
 152         closedir(dir);
 153         return ret;
 154 }
 155
 156 /*
 157  * Since 2.6.29 (patch 784aae735d9b0bba3f8b9faef4c8b30df3bf0128) kernel sysfs
 158  * provides the real DM device names in /sys/block/<ptname>/dm/name
 159  */
 160 static char *get_dm_name(const char *ptname)
 161 {
 162         FILE    *f;
 163         size_t  sz;
 164         char    path[256], name[256], *res = NULL;
 165
 166         snprintf(path, sizeof(path), "/sys/block/%s/dm/name", ptname);
 167         if ((f = fopen(path, "r")) == NULL)
 168                 return NULL;
 169
 170         /* read "<name>\n" from sysfs */
 171         if (fgets(name, sizeof(name), f) && (sz = strlen(name)) > 1) {
 172                 name[sz - 1] = '\0';
 173                 snprintf(path, sizeof(path), "/dev/mapper/%s", name);
 174                 res = blkid_strdup(path);
 175         }
 176         fclose(f);
 177         return res;
 178 }
 179
 180 /*
 181  * Probe a single block device to add to the device cache.
 182  */
 183 static void probe_one(blkid_cache cache, const char *ptname,
 184                       dev_t devno, int pri, int only_if_new)
 185 {
 186         blkid_dev dev = NULL;
 187         struct list_head *p, *pnext;
 188         const char **dir;
 189         char *devname = NULL;
 190
 191         /* See if we already have this device number in the cache. */
 192         list_for_each_safe(p, pnext, &cache->bic_devs) {
 193                 blkid_dev tmp = list_entry(p, struct blkid_struct_dev,
 194                                            bid_devs);
 195                 if (tmp->bid_devno == devno) {
 196                         if (only_if_new && !access(tmp->bid_name, F_OK))
 197                                 return;
 198                         dev = blkid_verify(cache, tmp);
 199                         if (dev && (dev->bid_flags & BLKID_BID_FL_VERIFIED))
 200                                 break;
 201                         dev = 0;
 202                 }
 203         }
 204         if (dev && dev->bid_devno == devno)
 205                 goto set_pri;
 206
 207         /* Try to translate private device-mapper dm-<N> names
 208          * to standard /dev/mapper/<name>.
 209          */
 210         if (!strncmp(ptname, "dm-", 3) && isdigit(ptname[3])) {
 211                 devname = get_dm_name(ptname);
 212                 if (!devname)
 213                         blkid__scan_dir("/dev/mapper", devno, 0, &devname);
 214                 if (devname)
 215                         goto get_dev;
 216         }
 217
 218         /*
 219          * Take a quick look at /dev/ptname for the device number.  We check
 220          * all of the likely device directories.  If we don't find it, or if
 221          * the stat information doesn't check out, use blkid_devno_to_devname()
 222          * to find it via an exhaustive search for the device major/minor.
 223          */
 224         for (dir = dirlist; *dir; dir++) {
 225                 struct stat st;
 226                 char device[256];
 227
 228                 sprintf(device, "%s/%s", *dir, ptname);
 229                 if ((dev = blkid_get_dev(cache, device, BLKID_DEV_FIND)) &&
 230                     dev->bid_devno == devno)
 231                         goto set_pri;
 232
 233                 if (stat(device, &st) == 0 && S_ISBLK(st.st_mode) &&
 234                     st.st_rdev == devno) {
 235                         devname = blkid_strdup(device);
 236                         goto get_dev;
 237                 }
 238         }
 239         /* Do a short-cut scan of /dev/mapper first */
 240         if (!devname)
 241                 devname = get_dm_name(ptname);
 242         if (!devname)
 243                 blkid__scan_dir("/dev/mapper", devno, 0, &devname);
 244         if (!devname) {
 245                 devname = blkid_devno_to_devname(devno);
 246                 if (!devname)
 247                         return;
 248         }
 249 get_dev:
 250         dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
 251         free(devname);
 252 set_pri:
 253         if (dev) {
 254                 if (pri)
 255                         dev->bid_pri = pri;
 256                 else if (!strncmp(dev->bid_name, "/dev/mapper/", 11)) {
 257                         dev->bid_pri = BLKID_PRI_DM;
 258                         if (is_dm_leaf(ptname))
 259                                 dev->bid_pri += 5;
 260                 } else if (!strncmp(ptname, "md", 2))
 261                         dev->bid_pri = BLKID_PRI_MD;
 262         }
 263         return;
 264 }
 265
 266 #define PROC_PARTITIONS "/proc/partitions"
 267 #define VG_DIR          "/proc/lvm/VGs"
 268
 269 /*
 270  * This function initializes the UUID cache with devices from the LVM
 271  * proc hierarchy.  We currently depend on the names of the LVM
 272  * hierarchy giving us the device structure in /dev.  (XXX is this a
 273  * safe thing to do?)
 274  */
 275 #ifdef VG_DIR
 276 static dev_t lvm_get_devno(const char *lvm_device)
 277 {
 278         FILE *lvf;
 279         char buf[1024];
 280         int ma, mi;
 281         dev_t ret = 0;
 282
 283         DBG(DEBUG_DEVNAME, printf("opening %s\n", lvm_device));
 284         if ((lvf = fopen(lvm_device, "r")) == NULL) {
 285                 DBG(DEBUG_DEVNAME, printf("%s: (%d) %s\n", lvm_device, errno,
 286                                           strerror(errno)));
 287                 return 0;
 288         }
 289
 290         while (fgets(buf, sizeof(buf), lvf)) {
 291                 if (sscanf(buf, "device: %d:%d", &ma, &mi) == 2) {
 292                         ret = makedev(ma, mi);
 293                         break;
 294                 }
 295         }
 296         fclose(lvf);
 297
 298         return ret;
 299 }
 300
 301 static void lvm_probe_all(blkid_cache cache, int only_if_new)
 302 {
 303         DIR             *vg_list;
 304         struct dirent   *vg_iter;
 305         int             vg_len = strlen(VG_DIR);
 306         dev_t           dev;
 307
 308         if ((vg_list = opendir(VG_DIR)) == NULL)
 309                 return;
 310
 311         DBG(DEBUG_DEVNAME, printf("probing LVM devices under %s\n", VG_DIR));
 312
 313         while ((vg_iter = readdir(vg_list)) != NULL) {
 314                 DIR             *lv_list;
 315                 char            *vdirname;
 316                 char            *vg_name;
 317                 struct dirent   *lv_iter;
 318
 319                 vg_name = vg_iter->d_name;
 320                 if (!strcmp(vg_name, ".") || !strcmp(vg_name, ".."))
 321                         continue;
 322                 vdirname = malloc(vg_len + strlen(vg_name) + 8);
 323                 if (!vdirname)
 324                         goto exit;
 325                 sprintf(vdirname, "%s/%s/LVs", VG_DIR, vg_name);
 326
 327                 lv_list = opendir(vdirname);
 328                 free(vdirname);
 329                 if (lv_list == NULL)
 330                         continue;
 331
 332                 while ((lv_iter = readdir(lv_list)) != NULL) {
 333                         char            *lv_name, *lvm_device;
 334
 335                         lv_name = lv_iter->d_name;
 336                         if (!strcmp(lv_name, ".") || !strcmp(lv_name, ".."))
 337                                 continue;
 338
 339                         lvm_device = malloc(vg_len + strlen(vg_name) +
 340                                             strlen(lv_name) + 8);
 341                         if (!lvm_device) {
 342                                 closedir(lv_list);
 343                                 goto exit;
 344                         }
 345                         sprintf(lvm_device, "%s/%s/LVs/%s", VG_DIR, vg_name,
 346                                 lv_name);
 347                         dev = lvm_get_devno(lvm_device);
 348                         sprintf(lvm_device, "%s/%s", vg_name, lv_name);
 349                         DBG(DEBUG_DEVNAME, printf("LVM dev %s: devno 0x%04X\n",
 350                                                   lvm_device,
 351                                                   (unsigned int) dev));
 352                         probe_one(cache, lvm_device, dev, BLKID_PRI_LVM,
 353                                   only_if_new);
 354                         free(lvm_device);
 355                 }
 356                 closedir(lv_list);
 357         }
 358 exit:
 359         closedir(vg_list);
 360 }
 361 #endif
 362
 363 #define PROC_EVMS_VOLUMES "/proc/evms/volumes"
 364
 365 static int
 366 evms_probe_all(blkid_cache cache, int only_if_new)
 367 {
 368         char line[100];
 369         int ma, mi, sz, num = 0;
 370         FILE *procpt;
 371         char device[110];
 372
 373         procpt = fopen(PROC_EVMS_VOLUMES, "r");
 374         if (!procpt)
 375                 return 0;
 376         while (fgets(line, sizeof(line), procpt)) {
 377                 if (sscanf (line, " %d %d %d %*s %*s %[^\n ]",
 378                             &ma, &mi, &sz, device) != 4)
 379                         continue;
 380
 381                 DBG(DEBUG_DEVNAME, printf("Checking partition %s (%d, %d)\n",
 382                                           device, ma, mi));
 383
 384                 probe_one(cache, device, makedev(ma, mi), BLKID_PRI_EVMS,
 385                           only_if_new);
 386                 num++;
 387         }
 388         fclose(procpt);
 389         return num;
 390 }
 391
 392 /*
 393  * Read the device data for all available block devices in the system.
 394  */
 395 static int probe_all(blkid_cache cache, int only_if_new)
 396 {
 397         FILE *proc;
 398         char line[1024];
 399         char ptname0[128], ptname1[128], *ptname = 0;
 400         char *ptnames[2];
 401         dev_t devs[2];
 402         int ma, mi;
 403         unsigned long long sz;
 404         int lens[2] = { 0, 0 };
 405         int which = 0, last = 0;
 406         struct list_head *p, *pnext;
 407
 408         ptnames[0] = ptname0;
 409         ptnames[1] = ptname1;
 410
 411         if (!cache)
 412                 return -BLKID_ERR_PARAM;
 413
 414         if (cache->bic_flags & BLKID_BIC_FL_PROBED &&
 415             time(0) - cache->bic_time < BLKID_PROBE_INTERVAL)
 416                 return 0;
 417
 418         blkid_read_cache(cache);
 419         evms_probe_all(cache, only_if_new);
 420 #ifdef VG_DIR
 421         lvm_probe_all(cache, only_if_new);
 422 #endif
 423
 424         proc = fopen(PROC_PARTITIONS, "r");
 425         if (!proc)
 426                 return -BLKID_ERR_PROC;
 427
 428         while (fgets(line, sizeof(line), proc)) {
 429                 last = which;
 430                 which ^= 1;
 431                 ptname = ptnames[which];
 432
 433                 if (sscanf(line, " %d %d %llu %128[^\n ]",
 434                            &ma, &mi, &sz, ptname) != 4)
 435                         continue;
 436                 devs[which] = makedev(ma, mi);
 437
 438                 DBG(DEBUG_DEVNAME, printf("read partition name %s\n", ptname));
 439
 440                 /* Skip whole disk devs unless they have no partitions.
 441                  * If base name of device has changed, also
 442                  * check previous dev to see if it didn't have a partn.
 443                  * heuristic: partition name ends in a digit, & partition
 444                  * names contain whole device name as substring.
 445                  *
 446                  * Skip extended partitions.
 447                  * heuristic: size is 1
 448                  *
 449                  * FIXME: skip /dev/{ida,cciss,rd} whole-disk devs
 450                  */
 451
 452                 lens[which] = strlen(ptname);
 453
 454                 /* ends in a digit, clearly a partition, so check */
 455                 if (isdigit(ptname[lens[which] - 1])) {
 456                         DBG(DEBUG_DEVNAME,
 457                             printf("partition dev %s, devno 0x%04X\n",
 458                                    ptname, (unsigned int) devs[which]));
 459
 460                         if (sz > 1)
 461                                 probe_one(cache, ptname, devs[which], 0,
 462                                           only_if_new);
 463                         lens[which] = 0;        /* mark as checked */
 464                 }
 465
 466                 /*
 467                  * If last was a whole disk and we just found a partition
 468                  * on it, remove the whole-disk dev from the cache if
 469                  * it exists.
 470                  */
 471                 if (lens[last] && !strncmp(ptnames[last], ptname, lens[last])) {
 472                         list_for_each_safe(p, pnext, &cache->bic_devs) {
 473                                 blkid_dev tmp;
 474
 475                                 /* find blkid dev for the whole-disk devno */
 476                                 tmp = list_entry(p, struct blkid_struct_dev,
 477                                                  bid_devs);
 478                                 if (tmp->bid_devno == devs[last]) {
 479                                         DBG(DEBUG_DEVNAME,
 480                                                 printf("freeing %s\n",
 481                                                        tmp->bid_name));
 482                                         blkid_free_dev(tmp);
 483                                         cache->bic_flags |= BLKID_BIC_FL_CHANGED;
 484                                         break;
 485                                 }
 486                         }
 487                         lens[last] = 0;
 488                 }
 489                 /*
 490                  * If last was not checked because it looked like a whole-disk
 491                  * dev, and the device's base name has changed,
 492                  * check last as well.
 493                  */
 494                 if (lens[last] && strncmp(ptnames[last], ptname, lens[last])) {
 495                         DBG(DEBUG_DEVNAME,
 496                             printf("whole dev %s, devno 0x%04X\n",
 497                                    ptnames[last], (unsigned int) devs[last]));
 498                         probe_one(cache, ptnames[last], devs[last], 0,
 499                                   only_if_new);
 500                         lens[last] = 0;
 501                 }
 502         }
 503
 504         /* Handle the last device if it wasn't partitioned */
 505         if (lens[which])
 506                 probe_one(cache, ptname, devs[which], 0, only_if_new);
 507
 508         fclose(proc);
 509         blkid_flush_cache(cache);
 510         return 0;
 511 }
 512
 513 int blkid_probe_all(blkid_cache cache)
 514 {
 515         int ret;
 516
 517         DBG(DEBUG_PROBE, printf("Begin blkid_probe_all()\n"));
 518         ret = probe_all(cache, 0);
 519         cache->bic_time = time(0);
 520         cache->bic_flags |= BLKID_BIC_FL_PROBED;
 521         DBG(DEBUG_PROBE, printf("End blkid_probe_all()\n"));
 522         return ret;
 523 }
 524
 525 int blkid_probe_all_new(blkid_cache cache)
 526 {
 527         int ret;
 528
 529         DBG(DEBUG_PROBE, printf("Begin blkid_probe_all_new()\n"));
 530         ret = probe_all(cache, 1);
 531         DBG(DEBUG_PROBE, printf("End blkid_probe_all_new()\n"));
 532         return ret;
 533 }
 534
 535
 536 #ifdef TEST_PROGRAM
 537 int main(int argc, char **argv)
 538 {
 539         blkid_cache cache = NULL;
 540         int ret;
 541
 542         blkid_debug_mask = DEBUG_ALL;
 543         if (argc != 1) {
 544                 fprintf(stderr, "Usage: %s\n"
 545                         "Probe all devices and exit\n", argv[0]);
 546                 exit(1);
 547         }
 548         if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
 549                 fprintf(stderr, "%s: error creating cache (%d)\n",
 550                         argv[0], ret);
 551                 exit(1);
 552         }
 553         if (blkid_probe_all(cache) < 0)
 554                 printf("%s: error probing devices\n", argv[0]);
 555
 556         blkid_put_cache(cache);
 557         return (0);
 558 }
 559 #endif