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