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 #ifdef HAVE_SYS_SYSMACROS_H
  40 #include <sys/sysmacros.h>
  41 #endif
  42 #include <time.h>
  43
  44 #include "blkidP.h"
  45
  46 /*
  47  * Find a dev struct in the cache by device name, if available.
  48  *
  49  * If there is no entry with the specified device name, and the create
  50  * flag is set, then create an empty device entry.
  51  */
  52 blkid_dev blkid_get_dev(blkid_cache cache, const char *devname, int flags)
  53 {
  54         blkid_dev dev = NULL, tmp;
  55         struct list_head *p, *pnext;
  56
  57         if (!cache || !devname)
  58                 return NULL;
  59
  60         list_for_each(p, &cache->bic_devs) {
  61                 tmp = list_entry(p, struct blkid_struct_dev, bid_devs);
  62                 if (strcmp(tmp->bid_name, devname))
  63                         continue;
  64
  65                 DBG(DEBUG_DEVNAME,
  66                     printf("found devname %s in cache\n", tmp->bid_name));
  67                 dev = tmp;
  68                 break;
  69         }
  70
  71         if (!dev && (flags & BLKID_DEV_CREATE)) {
  72                 if (access(devname, F_OK) < 0)
  73                         return NULL;
  74                 dev = blkid_new_dev();
  75                 if (!dev)
  76                         return NULL;
  77                 dev->bid_time = INT_MIN;
  78                 dev->bid_name = blkid_strdup(devname);
  79                 dev->bid_cache = cache;
  80                 list_add_tail(&dev->bid_devs, &cache->bic_devs);
  81                 cache->bic_flags |= BLKID_BIC_FL_CHANGED;
  82         }
  83
  84         if (flags & BLKID_DEV_VERIFY) {
  85                 dev = blkid_verify(cache, dev);
  86                 if (!dev || !(dev->bid_flags & BLKID_BID_FL_VERIFIED))
  87                         return dev;
  88                 /*
  89                  * If the device is verified, then search the blkid
  90                  * cache for any entries that match on the type, uuid,
  91                  * and label, and verify them; if a cache entry can
  92                  * not be verified, then it's stale and so we remove
  93                  * it.
  94                  */
  95                 list_for_each_safe(p, pnext, &cache->bic_devs) {
  96                         blkid_dev dev2;
  97                         dev2 = list_entry(p, struct blkid_struct_dev, bid_devs);
  98                         if (dev2->bid_flags & BLKID_BID_FL_VERIFIED)
  99                                 continue;
 100                         if (!dev->bid_type || !dev2->bid_type ||
 101                             strcmp(dev->bid_type, dev2->bid_type))
 102                                 continue;
 103                         if (dev->bid_label && dev2->bid_label &&
 104                             strcmp(dev->bid_label, dev2->bid_label))
 105                                 continue;
 106                         if (dev->bid_uuid && dev2->bid_uuid &&
 107                             strcmp(dev->bid_uuid, dev2->bid_uuid))
 108                                 continue;
 109                         if ((dev->bid_label && !dev2->bid_label) ||
 110                             (!dev->bid_label && dev2->bid_label) ||
 111                             (dev->bid_uuid && !dev2->bid_uuid) ||
 112                             (!dev->bid_uuid && dev2->bid_uuid))
 113                                 continue;
 114                         dev2 = blkid_verify(cache, dev2);
 115                         if (dev2 && !(dev2->bid_flags & BLKID_BID_FL_VERIFIED))
 116                                 blkid_free_dev(dev2);
 117                 }
 118         }
 119         return dev;
 120 }
 121
 122 /* Directories where we will try to search for device names */
 123 static const char *dirlist[] = { "/dev", "/devfs", "/devices", NULL };
 124
 125 static int is_dm_leaf(const char *devname)
 126 {
 127         struct dirent   *de, *d_de;
 128         DIR             *dir, *d_dir;
 129         char            path[300];
 130         int             ret = 1;
 131
 132         if ((dir = opendir("/sys/block")) == NULL)
 133                 return 0;
 134         while ((de = readdir(dir)) != NULL) {
 135                 if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..") ||
 136                     !strcmp(de->d_name, devname) ||
 137                     strncmp(de->d_name, "dm-", 3) ||
 138                     strlen(de->d_name) > sizeof(path)-32)
 139                         continue;
 140                 sprintf(path, "/sys/block/%s/slaves", de->d_name);
 141                 if ((d_dir = opendir(path)) == NULL)
 142                         continue;
 143                 while ((d_de = readdir(d_dir)) != NULL) {
 144                         if (!strcmp(d_de->d_name, devname)) {
 145                                 ret = 0;
 146                                 break;
 147                         }
 148                 }
 149                 closedir(d_dir);
 150                 if (!ret)
 151                         break;
 152         }
 153         closedir(dir);
 154         return ret;
 155 }
 156
 157 /*
 158  * Since 2.6.29 (patch 784aae735d9b0bba3f8b9faef4c8b30df3bf0128) kernel sysfs
 159  * provides the real DM device names in /sys/block/<ptname>/dm/name
 160  */
 161 static char *get_dm_name(const char *ptname)
 162 {
 163         FILE    *f;
 164         size_t  sz;
 165         char    path[300], name[256], *res = NULL;
 166
 167         snprintf(path, sizeof(path), "/sys/block/%s/dm/name", ptname);
 168         if ((f = fopen(path, "r")) == NULL)
 169                 return NULL;
 170
 171         /* read "<name>\n" from sysfs */
 172         if (fgets(name, sizeof(name), f) && (sz = strlen(name)) > 1) {
 173                 name[sz - 1] = '\0';
 174                 snprintf(path, sizeof(path), "/dev/mapper/%s", name);
 175                 res = blkid_strdup(path);
 176         }
 177         fclose(f);
 178         return res;
 179 }
 180
 181 /*
 182  * Probe a single block device to add to the device cache.
 183  */
 184 static void probe_one(blkid_cache cache, const char *ptname,
 185                       dev_t devno, int pri, int only_if_new)
 186 {
 187         blkid_dev dev = NULL;
 188         struct list_head *p, *pnext;
 189         const char **dir;
 190         char *devname = NULL;
 191
 192         /* See if we already have this device number in the cache. */
 193         list_for_each_safe(p, pnext, &cache->bic_devs) {
 194                 blkid_dev tmp = list_entry(p, struct blkid_struct_dev,
 195                                            bid_devs);
 196                 if (tmp->bid_devno == devno) {
 197                         if (only_if_new && !access(tmp->bid_name, F_OK))
 198                                 return;
 199                         dev = blkid_verify(cache, tmp);
 200                         if (dev && (dev->bid_flags & BLKID_BID_FL_VERIFIED))
 201                                 break;
 202                         dev = 0;
 203                 }
 204         }
 205         if (dev && dev->bid_devno == devno)
 206                 goto set_pri;
 207
 208         /* Try to translate private device-mapper dm-<N> names
 209          * to standard /dev/mapper/<name>.
 210          */
 211         if (!strncmp(ptname, "dm-", 3) && isdigit(ptname[3])) {
 212                 devname = get_dm_name(ptname);
 213                 if (!devname)
 214                         blkid__scan_dir("/dev/mapper", devno, 0, &devname);
 215                 if (devname)
 216                         goto get_dev;
 217         }
 218
 219         /*
 220          * Take a quick look at /dev/ptname for the device number.  We check
 221          * all of the likely device directories.  If we don't find it, or if
 222          * the stat information doesn't check out, use blkid_devno_to_devname()
 223          * to find it via an exhaustive search for the device major/minor.
 224          */
 225         for (dir = dirlist; *dir; dir++) {
 226                 struct stat st;
 227                 char device[256];
 228
 229                 sprintf(device, "%s/%s", *dir, ptname);
 230                 if ((dev = blkid_get_dev(cache, device, BLKID_DEV_FIND)) &&
 231                     dev->bid_devno == devno)
 232                         goto set_pri;
 233
 234                 if (stat(device, &st) == 0 &&
 235                     blkidP_is_disk_device(st.st_mode) &&
 236                     st.st_rdev == devno) {
 237                         devname = blkid_strdup(device);
 238                         goto get_dev;
 239                 }
 240         }
 241         /* Do a short-cut scan of /dev/mapper first */
 242         if (!devname)
 243                 devname = get_dm_name(ptname);
 244         if (!devname)
 245                 blkid__scan_dir("/dev/mapper", devno, 0, &devname);
 246         if (!devname) {
 247                 devname = blkid_devno_to_devname(devno);
 248                 if (!devname)
 249                         return;
 250         }
 251 get_dev:
 252         dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
 253         free(devname);
 254 set_pri:
 255         if (dev) {
 256                 if (pri)
 257                         dev->bid_pri = pri;
 258                 else if (!strncmp(dev->bid_name, "/dev/mapper/", 11)) {
 259                         dev->bid_pri = BLKID_PRI_DM;
 260                         if (is_dm_leaf(ptname))
 261                                 dev->bid_pri += 5;
 262                 } else if (!strncmp(ptname, "md", 2))
 263                         dev->bid_pri = BLKID_PRI_MD;
 264         }
 265         return;
 266 }
 267
 268 #define PROC_PARTITIONS "/proc/partitions"
 269 #define VG_DIR          "/proc/lvm/VGs"
 270
 271 /*
 272  * This function initializes the UUID cache with devices from the LVM
 273  * proc hierarchy.  We currently depend on the names of the LVM
 274  * hierarchy giving us the device structure in /dev.  (XXX is this a
 275  * safe thing to do?)
 276  */
 277 #ifdef VG_DIR
 278 static dev_t lvm_get_devno(const char *lvm_device)
 279 {
 280         FILE *lvf;
 281         char buf[1024];
 282         int ma, mi;
 283         dev_t ret = 0;
 284
 285         DBG(DEBUG_DEVNAME, printf("opening %s\n", lvm_device));
 286         if ((lvf = fopen(lvm_device, "r")) == NULL) {
 287                 DBG(DEBUG_DEVNAME, printf("%s: (%d) %s\n", lvm_device, errno,
 288                                           strerror(errno)));
 289                 return 0;
 290         }
 291
 292         while (fgets(buf, sizeof(buf), lvf)) {
 293                 if (sscanf(buf, "device: %d:%d", &ma, &mi) == 2) {
 294                         ret = makedev(ma, mi);
 295                         break;
 296                 }
 297         }
 298         fclose(lvf);
 299
 300         return ret;
 301 }
 302
 303 static void lvm_probe_all(blkid_cache cache, int only_if_new)
 304 {
 305         DIR             *vg_list;
 306         struct dirent   *vg_iter;
 307         int             vg_len = strlen(VG_DIR);
 308         dev_t           dev;
 309
 310         if ((vg_list = opendir(VG_DIR)) == NULL)
 311                 return;
 312
 313         DBG(DEBUG_DEVNAME, printf("probing LVM devices under %s\n", VG_DIR));
 314
 315         while ((vg_iter = readdir(vg_list)) != NULL) {
 316                 DIR             *lv_list;
 317                 char            *vdirname;
 318                 char            *vg_name;
 319                 struct dirent   *lv_iter;
 320
 321                 vg_name = vg_iter->d_name;
 322                 if (!strcmp(vg_name, ".") || !strcmp(vg_name, ".."))
 323                         continue;
 324                 vdirname = malloc(vg_len + strlen(vg_name) + 8);
 325                 if (!vdirname)
 326                         goto exit;
 327                 sprintf(vdirname, "%s/%s/LVs", VG_DIR, vg_name);
 328
 329                 lv_list = opendir(vdirname);
 330                 free(vdirname);
 331                 if (lv_list == NULL)
 332                         continue;
 333
 334                 while ((lv_iter = readdir(lv_list)) != NULL) {
 335                         char            *lv_name, *lvm_device;
 336
 337                         lv_name = lv_iter->d_name;
 338                         if (!strcmp(lv_name, ".") || !strcmp(lv_name, ".."))
 339                                 continue;
 340
 341                         lvm_device = malloc(vg_len + strlen(vg_name) +
 342                                             strlen(lv_name) + 8);
 343                         if (!lvm_device) {
 344                                 closedir(lv_list);
 345                                 goto exit;
 346                         }
 347                         sprintf(lvm_device, "%s/%s/LVs/%s", VG_DIR, vg_name,
 348                                 lv_name);
 349                         dev = lvm_get_devno(lvm_device);
 350                         sprintf(lvm_device, "%s/%s", vg_name, lv_name);
 351                         DBG(DEBUG_DEVNAME, printf("LVM dev %s: devno 0x%04X\n",
 352                                                   lvm_device,
 353                                                   (unsigned int) dev));
 354                         probe_one(cache, lvm_device, dev, BLKID_PRI_LVM,
 355                                   only_if_new);
 356                         free(lvm_device);
 357                 }
 358                 closedir(lv_list);
 359         }
 360 exit:
 361         closedir(vg_list);
 362 }
 363 #endif
 364
 365 #define PROC_EVMS_VOLUMES "/proc/evms/volumes"
 366
 367 static int
 368 evms_probe_all(blkid_cache cache, int only_if_new)
 369 {
 370         char line[100];
 371         int ma, mi, sz, num = 0;
 372         FILE *procpt;
 373         char device[110];
 374
 375         procpt = fopen(PROC_EVMS_VOLUMES, "r");
 376         if (!procpt)
 377                 return 0;
 378         while (fgets(line, sizeof(line), procpt)) {
 379                 if (sscanf (line, " %d %d %d %*s %*s %[^\n ]",
 380                             &ma, &mi, &sz, device) != 4)
 381                         continue;
 382
 383                 DBG(DEBUG_DEVNAME, printf("Checking partition %s (%d, %d)\n",
 384                                           device, ma, mi));
 385
 386                 probe_one(cache, device, makedev(ma, mi), BLKID_PRI_EVMS,
 387                           only_if_new);
 388                 num++;
 389         }
 390         fclose(procpt);
 391         return num;
 392 }
 393
 394 /*
 395  * Read the device data for all available block devices in the system.
 396  */
 397 static int probe_all(blkid_cache cache, int only_if_new)
 398 {
 399         FILE *proc;
 400         char line[1024];
 401         char ptname0[129], ptname1[129], *ptname = 0;
 402         char *ptnames[2];
 403         dev_t devs[2];
 404         int ma, mi;
 405         unsigned long long sz;
 406         int lens[2] = { 0, 0 };
 407         int which = 0, last = 0;
 408         struct list_head *p, *pnext;
 409
 410         ptnames[0] = ptname0;
 411         ptnames[1] = ptname1;
 412
 413         if (!cache)
 414                 return -BLKID_ERR_PARAM;
 415
 416         if (cache->bic_flags & BLKID_BIC_FL_PROBED &&
 417             time(0) - cache->bic_time < BLKID_PROBE_INTERVAL)
 418                 return 0;
 419
 420         blkid_read_cache(cache);
 421         evms_probe_all(cache, only_if_new);
 422 #ifdef VG_DIR
 423         lvm_probe_all(cache, only_if_new);
 424 #endif
 425
 426         proc = fopen(PROC_PARTITIONS, "r");
 427         if (!proc)
 428                 return -BLKID_ERR_PROC;
 429
 430         while (fgets(line, sizeof(line), proc)) {
 431                 last = which;
 432                 which ^= 1;
 433                 ptname = ptnames[which];
 434
 435                 if (sscanf(line, " %d %d %llu %128[^\n ]",
 436                            &ma, &mi, &sz, ptname) != 4)
 437                         continue;
 438                 devs[which] = makedev(ma, mi);
 439
 440                 DBG(DEBUG_DEVNAME, printf("read partition name %s\n", ptname));
 441
 442                 /* Skip whole disk devs unless they have no partitions.
 443                  * If base name of device has changed, also
 444                  * check previous dev to see if it didn't have a partn.
 445                  * heuristic: partition name ends in a digit, & partition
 446                  * names contain whole device name as substring.
 447                  *
 448                  * Skip extended partitions.
 449                  * heuristic: size is 1
 450                  *
 451                  * FIXME: skip /dev/{ida,cciss,rd} whole-disk devs
 452                  */
 453
 454                 lens[which] = strlen(ptname);
 455
 456                 /* ends in a digit, clearly a partition, so check */
 457                 if (isdigit(ptname[lens[which] - 1])) {
 458                         DBG(DEBUG_DEVNAME,
 459                             printf("partition dev %s, devno 0x%04X\n",
 460                                    ptname, (unsigned int) devs[which]));
 461
 462                         if (sz > 1)
 463                                 probe_one(cache, ptname, devs[which], 0,
 464                                           only_if_new);
 465                         lens[which] = 0;        /* mark as checked */
 466                 }
 467
 468                 /*
 469                  * If last was a whole disk and we just found a partition
 470                  * on it, remove the whole-disk dev from the cache if
 471                  * it exists.
 472                  */
 473                 if (lens[last] && !strncmp(ptnames[last], ptname, lens[last])) {
 474                         list_for_each_safe(p, pnext, &cache->bic_devs) {
 475                                 blkid_dev tmp;
 476
 477                                 /* find blkid dev for the whole-disk devno */
 478                                 tmp = list_entry(p, struct blkid_struct_dev,
 479                                                  bid_devs);
 480                                 if (tmp->bid_devno == devs[last]) {
 481                                         DBG(DEBUG_DEVNAME,
 482                                                 printf("freeing %s\n",
 483                                                        tmp->bid_name));
 484                                         blkid_free_dev(tmp);
 485                                         cache->bic_flags |= BLKID_BIC_FL_CHANGED;
 486                                         break;
 487                                 }
 488                         }
 489                         lens[last] = 0;
 490                 }
 491                 /*
 492                  * If last was not checked because it looked like a whole-disk
 493                  * dev, and the device's base name has changed,
 494                  * check last as well.
 495                  */
 496                 if (lens[last] && strncmp(ptnames[last], ptname, lens[last])) {
 497                         DBG(DEBUG_DEVNAME,
 498                             printf("whole dev %s, devno 0x%04X\n",
 499                                    ptnames[last], (unsigned int) devs[last]));
 500                         probe_one(cache, ptnames[last], devs[last], 0,
 501                                   only_if_new);
 502                         lens[last] = 0;
 503                 }
 504         }
 505
 506         /* Handle the last device if it wasn't partitioned */
 507         if (lens[which])
 508                 probe_one(cache, ptname, devs[which], 0, only_if_new);
 509
 510         fclose(proc);
 511         blkid_flush_cache(cache);
 512         return 0;
 513 }
 514
 515 int blkid_probe_all(blkid_cache cache)
 516 {
 517         int ret;
 518
 519         DBG(DEBUG_PROBE, printf("Begin blkid_probe_all()\n"));
 520         ret = probe_all(cache, 0);
 521         cache->bic_time = time(0);
 522         cache->bic_flags |= BLKID_BIC_FL_PROBED;
 523         DBG(DEBUG_PROBE, printf("End blkid_probe_all()\n"));
 524         return ret;
 525 }
 526
 527 int blkid_probe_all_new(blkid_cache cache)
 528 {
 529         int ret;
 530
 531         DBG(DEBUG_PROBE, printf("Begin blkid_probe_all_new()\n"));
 532         ret = probe_all(cache, 1);
 533         DBG(DEBUG_PROBE, printf("End blkid_probe_all_new()\n"));
 534         return ret;
 535 }
 536
 537
 538 #ifdef TEST_PROGRAM
 539 int main(int argc, char **argv)
 540 {
 541         blkid_cache cache = NULL;
 542         int ret;
 543
 544         blkid_debug_mask = DEBUG_ALL;
 545         if (argc != 1) {
 546                 fprintf(stderr, "Usage: %s\n"
 547                         "Probe all devices and exit\n", argv[0]);
 548                 exit(1);
 549         }
 550         if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
 551                 fprintf(stderr, "%s: error creating cache (%d)\n",
 552                         argv[0], ret);
 553                 exit(1);
 554         }
 555         if (blkid_probe_all(cache) < 0)
 556                 printf("%s: error probing devices\n", argv[0]);
 557
 558         blkid_put_cache(cache);
 559         return (0);
 560 }
 561 #endif