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[256]; 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[256], 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 && S_ISBLK(st.st_mode) && 235 st.st_rdev == devno) { 236 devname = blkid_strdup(device); 237 goto get_dev; 238 } 239 } 240 /* Do a short-cut scan of /dev/mapper first */ 241 if (!devname) 242 devname = get_dm_name(ptname); 243 if (!devname) 244 blkid__scan_dir("/dev/mapper", devno, 0, &devname); 245 if (!devname) { 246 devname = blkid_devno_to_devname(devno); 247 if (!devname) 248 return; 249 } 250 get_dev: 251 dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL); 252 free(devname); 253 set_pri: 254 if (dev) { 255 if (pri) 256 dev->bid_pri = pri; 257 else if (!strncmp(dev->bid_name, "/dev/mapper/", 11)) { 258 dev->bid_pri = BLKID_PRI_DM; 259 if (is_dm_leaf(ptname)) 260 dev->bid_pri += 5; 261 } else if (!strncmp(ptname, "md", 2)) 262 dev->bid_pri = BLKID_PRI_MD; 263 } 264 return; 265 } 266 267 #define PROC_PARTITIONS "/proc/partitions" 268 #define VG_DIR "/proc/lvm/VGs" 269 270 /* 271 * This function initializes the UUID cache with devices from the LVM 272 * proc hierarchy. We currently depend on the names of the LVM 273 * hierarchy giving us the device structure in /dev. (XXX is this a 274 * safe thing to do?) 275 */ 276 #ifdef VG_DIR 277 static dev_t lvm_get_devno(const char *lvm_device) 278 { 279 FILE *lvf; 280 char buf[1024]; 281 int ma, mi; 282 dev_t ret = 0; 283 284 DBG(DEBUG_DEVNAME, printf("opening %s\n", lvm_device)); 285 if ((lvf = fopen(lvm_device, "r")) == NULL) { 286 DBG(DEBUG_DEVNAME, printf("%s: (%d) %s\n", lvm_device, errno, 287 strerror(errno))); 288 return 0; 289 } 290 291 while (fgets(buf, sizeof(buf), lvf)) { 292 if (sscanf(buf, "device: %d:%d", &ma, &mi) == 2) { 293 ret = makedev(ma, mi); 294 break; 295 } 296 } 297 fclose(lvf); 298 299 return ret; 300 } 301 302 static void lvm_probe_all(blkid_cache cache, int only_if_new) 303 { 304 DIR *vg_list; 305 struct dirent *vg_iter; 306 int vg_len = strlen(VG_DIR); 307 dev_t dev; 308 309 if ((vg_list = opendir(VG_DIR)) == NULL) 310 return; 311 312 DBG(DEBUG_DEVNAME, printf("probing LVM devices under %s\n", VG_DIR)); 313 314 while ((vg_iter = readdir(vg_list)) != NULL) { 315 DIR *lv_list; 316 char *vdirname; 317 char *vg_name; 318 struct dirent *lv_iter; 319 320 vg_name = vg_iter->d_name; 321 if (!strcmp(vg_name, ".") || !strcmp(vg_name, "..")) 322 continue; 323 vdirname = malloc(vg_len + strlen(vg_name) + 8); 324 if (!vdirname) 325 goto exit; 326 sprintf(vdirname, "%s/%s/LVs", VG_DIR, vg_name); 327 328 lv_list = opendir(vdirname); 329 free(vdirname); 330 if (lv_list == NULL) 331 continue; 332 333 while ((lv_iter = readdir(lv_list)) != NULL) { 334 char *lv_name, *lvm_device; 335 336 lv_name = lv_iter->d_name; 337 if (!strcmp(lv_name, ".") || !strcmp(lv_name, "..")) 338 continue; 339 340 lvm_device = malloc(vg_len + strlen(vg_name) + 341 strlen(lv_name) + 8); 342 if (!lvm_device) { 343 closedir(lv_list); 344 goto exit; 345 } 346 sprintf(lvm_device, "%s/%s/LVs/%s", VG_DIR, vg_name, 347 lv_name); 348 dev = lvm_get_devno(lvm_device); 349 sprintf(lvm_device, "%s/%s", vg_name, lv_name); 350 DBG(DEBUG_DEVNAME, printf("LVM dev %s: devno 0x%04X\n", 351 lvm_device, 352 (unsigned int) dev)); 353 probe_one(cache, lvm_device, dev, BLKID_PRI_LVM, 354 only_if_new); 355 free(lvm_device); 356 } 357 closedir(lv_list); 358 } 359 exit: 360 closedir(vg_list); 361 } 362 #endif 363 364 #define PROC_EVMS_VOLUMES "/proc/evms/volumes" 365 366 static int 367 evms_probe_all(blkid_cache cache, int only_if_new) 368 { 369 char line[100]; 370 int ma, mi, sz, num = 0; 371 FILE *procpt; 372 char device[110]; 373 374 procpt = fopen(PROC_EVMS_VOLUMES, "r"); 375 if (!procpt) 376 return 0; 377 while (fgets(line, sizeof(line), procpt)) { 378 if (sscanf (line, " %d %d %d %*s %*s %[^\n ]", 379 &ma, &mi, &sz, device) != 4) 380 continue; 381 382 DBG(DEBUG_DEVNAME, printf("Checking partition %s (%d, %d)\n", 383 device, ma, mi)); 384 385 probe_one(cache, device, makedev(ma, mi), BLKID_PRI_EVMS, 386 only_if_new); 387 num++; 388 } 389 fclose(procpt); 390 return num; 391 } 392 393 /* 394 * Read the device data for all available block devices in the system. 395 */ 396 static int probe_all(blkid_cache cache, int only_if_new) 397 { 398 FILE *proc; 399 char line[1024]; 400 char ptname0[129], ptname1[129], *ptname = 0; 401 char *ptnames[2]; 402 dev_t devs[2]; 403 int ma, mi; 404 unsigned long long sz; 405 int lens[2] = { 0, 0 }; 406 int which = 0, last = 0; 407 struct list_head *p, *pnext; 408 409 ptnames[0] = ptname0; 410 ptnames[1] = ptname1; 411 412 if (!cache) 413 return -BLKID_ERR_PARAM; 414 415 if (cache->bic_flags & BLKID_BIC_FL_PROBED && 416 time(0) - cache->bic_time < BLKID_PROBE_INTERVAL) 417 return 0; 418 419 blkid_read_cache(cache); 420 evms_probe_all(cache, only_if_new); 421 #ifdef VG_DIR 422 lvm_probe_all(cache, only_if_new); 423 #endif 424 425 proc = fopen(PROC_PARTITIONS, "r"); 426 if (!proc) 427 return -BLKID_ERR_PROC; 428 429 while (fgets(line, sizeof(line), proc)) { 430 last = which; 431 which ^= 1; 432 ptname = ptnames[which]; 433 434 if (sscanf(line, " %d %d %llu %128[^\n ]", 435 &ma, &mi, &sz, ptname) != 4) 436 continue; 437 devs[which] = makedev(ma, mi); 438 439 DBG(DEBUG_DEVNAME, printf("read partition name %s\n", ptname)); 440 441 /* Skip whole disk devs unless they have no partitions. 442 * If base name of device has changed, also 443 * check previous dev to see if it didn't have a partn. 444 * heuristic: partition name ends in a digit, & partition 445 * names contain whole device name as substring. 446 * 447 * Skip extended partitions. 448 * heuristic: size is 1 449 * 450 * FIXME: skip /dev/{ida,cciss,rd} whole-disk devs 451 */ 452 453 lens[which] = strlen(ptname); 454 455 /* ends in a digit, clearly a partition, so check */ 456 if (isdigit(ptname[lens[which] - 1])) { 457 DBG(DEBUG_DEVNAME, 458 printf("partition dev %s, devno 0x%04X\n", 459 ptname, (unsigned int) devs[which])); 460 461 if (sz > 1) 462 probe_one(cache, ptname, devs[which], 0, 463 only_if_new); 464 lens[which] = 0; /* mark as checked */ 465 } 466 467 /* 468 * If last was a whole disk and we just found a partition 469 * on it, remove the whole-disk dev from the cache if 470 * it exists. 471 */ 472 if (lens[last] && !strncmp(ptnames[last], ptname, lens[last])) { 473 list_for_each_safe(p, pnext, &cache->bic_devs) { 474 blkid_dev tmp; 475 476 /* find blkid dev for the whole-disk devno */ 477 tmp = list_entry(p, struct blkid_struct_dev, 478 bid_devs); 479 if (tmp->bid_devno == devs[last]) { 480 DBG(DEBUG_DEVNAME, 481 printf("freeing %s\n", 482 tmp->bid_name)); 483 blkid_free_dev(tmp); 484 cache->bic_flags |= BLKID_BIC_FL_CHANGED; 485 break; 486 } 487 } 488 lens[last] = 0; 489 } 490 /* 491 * If last was not checked because it looked like a whole-disk 492 * dev, and the device's base name has changed, 493 * check last as well. 494 */ 495 if (lens[last] && strncmp(ptnames[last], ptname, lens[last])) { 496 DBG(DEBUG_DEVNAME, 497 printf("whole dev %s, devno 0x%04X\n", 498 ptnames[last], (unsigned int) devs[last])); 499 probe_one(cache, ptnames[last], devs[last], 0, 500 only_if_new); 501 lens[last] = 0; 502 } 503 } 504 505 /* Handle the last device if it wasn't partitioned */ 506 if (lens[which]) 507 probe_one(cache, ptname, devs[which], 0, only_if_new); 508 509 fclose(proc); 510 blkid_flush_cache(cache); 511 return 0; 512 } 513 514 int blkid_probe_all(blkid_cache cache) 515 { 516 int ret; 517 518 DBG(DEBUG_PROBE, printf("Begin blkid_probe_all()\n")); 519 ret = probe_all(cache, 0); 520 cache->bic_time = time(0); 521 cache->bic_flags |= BLKID_BIC_FL_PROBED; 522 DBG(DEBUG_PROBE, printf("End blkid_probe_all()\n")); 523 return ret; 524 } 525 526 int blkid_probe_all_new(blkid_cache cache) 527 { 528 int ret; 529 530 DBG(DEBUG_PROBE, printf("Begin blkid_probe_all_new()\n")); 531 ret = probe_all(cache, 1); 532 DBG(DEBUG_PROBE, printf("End blkid_probe_all_new()\n")); 533 return ret; 534 } 535 536 537 #ifdef TEST_PROGRAM 538 int main(int argc, char **argv) 539 { 540 blkid_cache cache = NULL; 541 int ret; 542 543 blkid_debug_mask = DEBUG_ALL; 544 if (argc != 1) { 545 fprintf(stderr, "Usage: %s\n" 546 "Probe all devices and exit\n", argv[0]); 547 exit(1); 548 } 549 if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) { 550 fprintf(stderr, "%s: error creating cache (%d)\n", 551 argv[0], ret); 552 exit(1); 553 } 554 if (blkid_probe_all(cache) < 0) 555 printf("%s: error probing devices\n", argv[0]); 556 557 blkid_put_cache(cache); 558 return (0); 559 } 560 #endif 561
