shlibs/blkid/src/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 #include <dirent.h>
  29 #if HAVE_SYS_STAT_H
  30 #include <sys/stat.h>
  31 #endif
  32 #if HAVE_ERRNO_H
  33 #include <errno.h>
  34 #endif
  35 #if HAVE_SYS_MKDEV_H
  36 #include <sys/mkdev.h>
  37 #endif
  38 #include <time.h>
  39
  40 #include "blkidP.h"
  41
  42 /*
  43  * Find a dev struct in the cache by device name, if available.
  44  *
  45  * If there is no entry with the specified device name, and the create
  46  * flag is set, then create an empty device entry.
  47  */
  48 blkid_dev blkid_get_dev(blkid_cache cache, const char *devname, int flags)
  49 {
  50         blkid_dev dev = NULL, tmp;
  51         struct list_head *p, *pnext;
  52
  53         if (!cache || !devname)
  54                 return NULL;
  55
  56         list_for_each(p, &cache->bic_devs) {
  57                 tmp = list_entry(p, struct blkid_struct_dev, bid_devs);
  58                 if (strcmp(tmp->bid_name, devname))
  59                         continue;
  60
  61                 DBG(DEBUG_DEVNAME,
  62                     printf("found devname %s in cache\n", tmp->bid_name));
  63                 dev = tmp;
  64                 break;
  65         }
  66
  67         if (!dev && (flags & BLKID_DEV_CREATE)) {
  68                 if (access(devname, F_OK) < 0)
  69                         return NULL;
  70                 dev = blkid_new_dev();
  71                 if (!dev)
  72                         return NULL;
  73                 dev->bid_time = INT_MIN;
  74                 dev->bid_name = blkid_strdup(devname);
  75                 dev->bid_cache = cache;
  76                 list_add_tail(&dev->bid_devs, &cache->bic_devs);
  77                 cache->bic_flags |= BLKID_BIC_FL_CHANGED;
  78         }
  79
  80         if (flags & BLKID_DEV_VERIFY) {
  81                 dev = blkid_verify(cache, dev);
  82                 if (!dev || !(dev->bid_flags & BLKID_BID_FL_VERIFIED))
  83                         return dev;
  84                 /*
  85                  * If the device is verified, then search the blkid
  86                  * cache for any entries that match on the type, uuid,
  87                  * and label, and verify them; if a cache entry can
  88                  * not be verified, then it's stale and so we remove
  89                  * it.
  90                  */
  91                 list_for_each_safe(p, pnext, &cache->bic_devs) {
  92                         blkid_dev dev2;
  93                         if (!p)
  94                                 break;
  95                         dev2 = list_entry(p, struct blkid_struct_dev, bid_devs);
  96                         if (dev2->bid_flags & BLKID_BID_FL_VERIFIED)
  97                                 continue;
  98                         if (!dev->bid_type || !dev2->bid_type ||
  99                             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 /* Directories where we will try to search for device names */
 121 static const char *dirlist[] = { "/dev", "/devfs", "/devices", NULL };
 122
 123 static int is_dm_leaf(const char *devname)
 124 {
 125         struct dirent   *de, *d_de;
 126         DIR             *dir, *d_dir;
 127         char            path[256];
 128         int             ret = 1;
 129
 130         if ((dir = opendir("/sys/block")) == NULL)
 131                 return 0;
 132         while ((de = readdir(dir)) != NULL) {
 133                 if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..") ||
 134                     !strcmp(de->d_name, devname) ||
 135                     strncmp(de->d_name, "dm-", 3) ||
 136                     strlen(de->d_name) > sizeof(path)-32)
 137                         continue;
 138                 sprintf(path, "/sys/block/%s/slaves", de->d_name);
 139                 if ((d_dir = opendir(path)) == NULL)
 140                         continue;
 141                 while ((d_de = readdir(d_dir)) != NULL) {
 142                         if (!strcmp(d_de->d_name, devname)) {
 143                                 ret = 0;
 144                                 break;
 145                         }
 146                 }
 147                 closedir(d_dir);
 148                 if (!ret)
 149                         break;
 150         }
 151         closedir(dir);
 152         return ret;
 153 }
 154
 155 /*
 156  * Since 2.6.29 (patch 784aae735d9b0bba3f8b9faef4c8b30df3bf0128) kernel sysfs
 157  * provides the real DM device names in /sys/block/<ptname>/dm/name
 158  */
 159 static char *get_dm_name(const char *ptname)
 160 {
 161         FILE    *f;
 162         size_t  sz;
 163         char    path[256], name[256], *res = NULL;
 164
 165         snprintf(path, sizeof(path), "/sys/block/%s/dm/name", ptname);
 166         if ((f = fopen(path, "r")) == NULL)
 167                 return NULL;
 168
 169         /* read "<name>\n" from sysfs */
 170         if (fgets(name, sizeof(name), f) && (sz = strlen(name)) > 1) {
 171                 name[sz - 1] = '\0';
 172                 snprintf(path, sizeof(path), "/dev/mapper/%s", name);
 173                 res = blkid_strdup(path);
 174         }
 175         fclose(f);
 176         return res;
 177 }
 178
 179 /*
 180  * Probe a single block device to add to the device cache.
 181  */
 182 static void probe_one(blkid_cache cache, const char *ptname,
 183                       dev_t devno, int pri, int only_if_new)
 184 {
 185         blkid_dev dev = NULL;
 186         struct list_head *p, *pnext;
 187         const char **dir;
 188         char *devname = NULL;
 189
 190         /* See if we already have this device number in the cache. */
 191         list_for_each_safe(p, pnext, &cache->bic_devs) {
 192                 blkid_dev tmp = list_entry(p, struct blkid_struct_dev,
 193                                            bid_devs);
 194                 if (tmp->bid_devno == devno) {
 195                         if (only_if_new && !access(tmp->bid_name, F_OK))
 196                                 return;
 197                         dev = blkid_verify(cache, tmp);
 198                         if (dev && (dev->bid_flags & BLKID_BID_FL_VERIFIED))
 199                                 break;
 200                         dev = 0;
 201                 }
 202         }
 203         if (dev && dev->bid_devno == devno)
 204                 goto set_pri;
 205
 206         /* Try to translate private device-mapper dm-<N> names
 207          * to standard /dev/mapper/<name>.
 208          */
 209         if (!strncmp(ptname, "dm-", 3) && isdigit(ptname[3])) {
 210                 devname = get_dm_name(ptname);
 211                 if (!devname)
 212                         blkid__scan_dir("/dev/mapper", devno, 0, &devname);
 213                 if (devname)
 214                         goto get_dev;
 215         }
 216
 217         /*
 218          * Take a quick look at /dev/ptname for the device number.  We check
 219          * all of the likely device directories.  If we don't find it, or if
 220          * the stat information doesn't check out, use blkid_devno_to_devname()
 221          * to find it via an exhaustive search for the device major/minor.
 222          */
 223         for (dir = dirlist; *dir; dir++) {
 224                 struct stat st;
 225                 char device[256];
 226
 227                 sprintf(device, "%s/%s", *dir, ptname);
 228                 if ((dev = blkid_get_dev(cache, device, BLKID_DEV_FIND)) &&
 229                     dev->bid_devno == devno)
 230                         goto set_pri;
 231
 232                 if (stat(device, &st) == 0 && S_ISBLK(st.st_mode) &&
 233                     st.st_rdev == devno) {
 234                         devname = blkid_strdup(device);
 235                         goto get_dev;
 236                 }
 237         }
 238         /* Do a short-cut scan of /dev/mapper first */
 239         if (!devname)
 240                 blkid__scan_dir("/dev/mapper", devno, 0, &devname);
 241         if (!devname) {
 242                 devname = blkid_devno_to_devname(devno);
 243                 if (!devname)
 244                         return;
 245         }
 246
 247 get_dev:
 248         dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
 249         free(devname);
 250
 251 set_pri:
 252         if (dev) {
 253                 if (pri)
 254                         dev->bid_pri = pri;
 255                 else if (!strncmp(dev->bid_name, "/dev/mapper/", 11)) {
 256                         dev->bid_pri = BLKID_PRI_DM;
 257                         if (is_dm_leaf(ptname))
 258                                 dev->bid_pri += 5;
 259                 } else if (!strncmp(ptname, "md", 2))
 260                         dev->bid_pri = BLKID_PRI_MD;
 261         }
 262         return;
 263 }
 264
 265 #define PROC_PARTITIONS "/proc/partitions"
 266 #define VG_DIR          "/proc/lvm/VGs"
 267
 268 /*
 269  * This function initializes the UUID cache with devices from the LVM
 270  * proc hierarchy.  We currently depend on the names of the LVM
 271  * hierarchy giving us the device structure in /dev.  (XXX is this a
 272  * safe thing to do?)
 273  */
 274 #ifdef VG_DIR
 275 static dev_t lvm_get_devno(const char *lvm_device)
 276 {
 277         FILE *lvf;
 278         char buf[1024];
 279         int ma, mi;
 280         dev_t ret = 0;
 281
 282         DBG(DEBUG_DEVNAME, printf("opening %s\n", lvm_device));
 283         if ((lvf = fopen(lvm_device, "r")) == NULL) {
 284                 DBG(DEBUG_DEVNAME, printf("%s: (%d) %s\n", lvm_device, errno,
 285                                           strerror(errno)));
 286                 return 0;
 287         }
 288
 289         while (fgets(buf, sizeof(buf), lvf)) {
 290                 if (sscanf(buf, "device: %d:%d", &ma, &mi) == 2) {
 291                         ret = makedev(ma, mi);
 292                         break;
 293                 }
 294         }
 295         fclose(lvf);
 296
 297         return ret;
 298 }
 299
 300 static void lvm_probe_all(blkid_cache cache, int only_if_new)
 301 {
 302         DIR             *vg_list;
 303         struct dirent   *vg_iter;
 304         int             vg_len = strlen(VG_DIR);
 305         dev_t           dev;
 306
 307         if ((vg_list = opendir(VG_DIR)) == NULL)
 308                 return;
 309
 310         DBG(DEBUG_DEVNAME, printf("probing LVM devices under %s\n", VG_DIR));
 311
 312         while ((vg_iter = readdir(vg_list)) != NULL) {
 313                 DIR             *lv_list;
 314                 char            *vdirname;
 315                 char            *vg_name;
 316                 struct dirent   *lv_iter;
 317
 318                 vg_name = vg_iter->d_name;
 319                 if (!strcmp(vg_name, ".") || !strcmp(vg_name, ".."))
 320                         continue;
 321                 vdirname = malloc(vg_len + strlen(vg_name) + 8);
 322                 if (!vdirname)
 323                         goto exit;
 324                 sprintf(vdirname, "%s/%s/LVs", VG_DIR, vg_name);
 325
 326                 lv_list = opendir(vdirname);
 327                 free(vdirname);
 328                 if (lv_list == NULL)
 329                         continue;
 330
 331                 while ((lv_iter = readdir(lv_list)) != NULL) {
 332                         char            *lv_name, *lvm_device;
 333
 334                         lv_name = lv_iter->d_name;
 335                         if (!strcmp(lv_name, ".") || !strcmp(lv_name, ".."))
 336                                 continue;
 337
 338                         lvm_device = malloc(vg_len + strlen(vg_name) +
 339                                             strlen(lv_name) + 8);
 340                         if (!lvm_device) {
 341                                 closedir(lv_list);
 342                                 goto exit;
 343                         }
 344                         sprintf(lvm_device, "%s/%s/LVs/%s", VG_DIR, vg_name,
 345                                 lv_name);
 346                         dev = lvm_get_devno(lvm_device);
 347                         sprintf(lvm_device, "%s/%s", vg_name, lv_name);
 348                         DBG(DEBUG_DEVNAME, printf("LVM dev %s: devno 0x%04X\n",
 349                                                   lvm_device,
 350                                                   (unsigned int) dev));
 351                         probe_one(cache, lvm_device, dev, BLKID_PRI_LVM,
 352                                   only_if_new);
 353                         free(lvm_device);
 354                 }
 355                 closedir(lv_list);
 356         }
 357 exit:
 358         closedir(vg_list);
 359 }
 360 #endif
 361
 362 #define PROC_EVMS_VOLUMES "/proc/evms/volumes"
 363
 364 static int
 365 evms_probe_all(blkid_cache cache, int only_if_new)
 366 {
 367         char line[100];
 368         int ma, mi, sz, num = 0;
 369         FILE *procpt;
 370         char device[110];
 371
 372         procpt = fopen(PROC_EVMS_VOLUMES, "r");
 373         if (!procpt)
 374                 return 0;
 375         while (fgets(line, sizeof(line), procpt)) {
 376                 if (sscanf (line, " %d %d %d %*s %*s %[^\n ]",
 377                             &ma, &mi, &sz, device) != 4)
 378                         continue;
 379
 380                 DBG(DEBUG_DEVNAME, printf("Checking partition %s (%d, %d)\n",
 381                                           device, ma, mi));
 382
 383                 probe_one(cache, device, makedev(ma, mi), BLKID_PRI_EVMS,
 384                           only_if_new);
 385                 num++;
 386         }
 387         fclose(procpt);
 388         return num;
 389 }
 390
 391 /*
 392  * Read the device data for all available block devices in the system.
 393  */
 394 static int probe_all(blkid_cache cache, int only_if_new)
 395 {
 396         FILE *proc;
 397         char line[1024];
 398         char ptname0[128], ptname1[128], *ptname = 0;
 399         char *ptnames[2];
 400         dev_t devs[2];
 401         int ma, mi;
 402         unsigned long long sz;
 403         int lens[2] = { 0, 0 };
 404         int which = 0, last = 0;
 405         struct list_head *p, *pnext;
 406
 407         ptnames[0] = ptname0;
 408         ptnames[1] = ptname1;
 409
 410         if (!cache)
 411                 return -BLKID_ERR_PARAM;
 412
 413         if (cache->bic_flags & BLKID_BIC_FL_PROBED &&
 414             time(0) - cache->bic_time < BLKID_PROBE_INTERVAL)
 415                 return 0;
 416
 417         blkid_read_cache(cache);
 418         evms_probe_all(cache, only_if_new);
 419 #ifdef VG_DIR
 420         lvm_probe_all(cache, only_if_new);
 421 #endif
 422
 423         proc = fopen(PROC_PARTITIONS, "r");
 424         if (!proc)
 425                 return -BLKID_ERR_PROC;
 426
 427         while (fgets(line, sizeof(line), proc)) {
 428                 last = which;
 429                 which ^= 1;
 430                 ptname = ptnames[which];
 431
 432                 if (sscanf(line, " %d %d %llu %128[^\n ]",
 433                            &ma, &mi, &sz, ptname) != 4)
 434                         continue;
 435                 devs[which] = makedev(ma, mi);
 436
 437                 DBG(DEBUG_DEVNAME, printf("read partition name %s\n", ptname));
 438
 439                 /* Skip whole disk devs unless they have no partitions.
 440                  * If base name of device has changed, also
 441                  * check previous dev to see if it didn't have a partn.
 442                  * heuristic: partition name ends in a digit, & partition
 443                  * names contain whole device name as substring.
 444                  *
 445                  * Skip extended partitions.
 446                  * heuristic: size is 1
 447                  *
 448                  * FIXME: skip /dev/{ida,cciss,rd} whole-disk devs
 449                  */
 450
 451                 lens[which] = strlen(ptname);
 452
 453                 /* ends in a digit, clearly a partition, so check */
 454                 if (isdigit(ptname[lens[which] - 1])) {
 455                         DBG(DEBUG_DEVNAME,
 456                             printf("partition dev %s, devno 0x%04X\n",
 457                                    ptname, (unsigned int) devs[which]));
 458
 459                         if (sz > 1)
 460                                 probe_one(cache, ptname, devs[which], 0,
 461                                           only_if_new);
 462                         lens[which] = 0;        /* mark as checked */
 463                 }
 464
 465                 /*
 466                  * If last was a whole disk and we just found a partition
 467                  * on it, remove the whole-disk dev from the cache if
 468                  * it exists.
 469                  */
 470                 if (lens[last] && !strncmp(ptnames[last], ptname, lens[last])) {
 471                         list_for_each_safe(p, pnext, &cache->bic_devs) {
 472                                 blkid_dev tmp;
 473
 474                                 /* find blkid dev for the whole-disk devno */
 475                                 tmp = list_entry(p, struct blkid_struct_dev,
 476                                                  bid_devs);
 477                                 if (tmp->bid_devno == devs[last]) {
 478                                         DBG(DEBUG_DEVNAME,
 479                                                 printf("freeing %s\n",
 480                                                        tmp->bid_name));
 481                                         blkid_free_dev(tmp);
 482                                         cache->bic_flags |= BLKID_BIC_FL_CHANGED;
 483                                         break;
 484                                 }
 485                         }
 486                         lens[last] = 0;
 487                 }
 488                 /*
 489                  * If last was not checked because it looked like a whole-disk
 490                  * dev, and the device's base name has changed,
 491                  * check last as well.
 492                  */
 493                 if (lens[last] && strncmp(ptnames[last], ptname, lens[last])) {
 494                         DBG(DEBUG_DEVNAME,
 495                             printf("whole dev %s, devno 0x%04X\n",
 496                                    ptnames[last], (unsigned int) devs[last]));
 497                         probe_one(cache, ptnames[last], devs[last], 0,
 498                                   only_if_new);
 499                         lens[last] = 0;
 500                 }
 501         }
 502
 503         /* Handle the last device if it wasn't partitioned */
 504         if (lens[which])
 505                 probe_one(cache, ptname, devs[which], 0, only_if_new);
 506
 507         fclose(proc);
 508         blkid_flush_cache(cache);
 509         return 0;
 510 }
 511
 512 int blkid_probe_all(blkid_cache cache)
 513 {
 514         int ret;
 515
 516         DBG(DEBUG_PROBE, printf("Begin blkid_probe_all()\n"));
 517         ret = probe_all(cache, 0);
 518         cache->bic_time = time(0);
 519         cache->bic_flags |= BLKID_BIC_FL_PROBED;
 520         DBG(DEBUG_PROBE, printf("End blkid_probe_all()\n"));
 521         return ret;
 522 }
 523
 524 int blkid_probe_all_new(blkid_cache cache)
 525 {
 526         int ret;
 527
 528         DBG(DEBUG_PROBE, printf("Begin blkid_probe_all_new()\n"));
 529         ret = probe_all(cache, 1);
 530         DBG(DEBUG_PROBE, printf("End blkid_probe_all_new()\n"));
 531         return ret;
 532 }
 533
 534
 535 #ifdef TEST_PROGRAM
 536 int main(int argc, char **argv)
 537 {
 538         blkid_cache cache = NULL;
 539         int ret;
 540
 541         blkid_init_debug(DEBUG_ALL);
 542         if (argc != 1) {
 543                 fprintf(stderr, "Usage: %s\n"
 544                         "Probe all devices and exit\n", argv[0]);
 545                 exit(1);
 546         }
 547         if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
 548                 fprintf(stderr, "%s: error creating cache (%d)\n",
 549                         argv[0], ret);
 550                 exit(1);
 551         }
 552         if (blkid_probe_all(cache) < 0)
 553                 printf("%s: error probing devices\n", argv[0]);
 554
 555         blkid_put_cache(cache);
 556         return (0);
 557 }
 558 #endif