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