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 558
