devname.c revision 4e60e06847c781efffc8c43342b7756bbe5cff45
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 */ 48blkid_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 */ 121static const char *dirlist[] = { "/dev", "/devfs", "/devices", NULL }; 122 123static 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 * Probe a single block device to add to the device cache. 157 */ 158static void probe_one(blkid_cache cache, const char *ptname, 159 dev_t devno, int pri, int only_if_new) 160{ 161 blkid_dev dev = NULL; 162 struct list_head *p, *pnext; 163 const char **dir; 164 char *devname = NULL; 165 166 /* See if we already have this device number in the cache. */ 167 list_for_each_safe(p, pnext, &cache->bic_devs) { 168 blkid_dev tmp = list_entry(p, struct blkid_struct_dev, 169 bid_devs); 170 if (tmp->bid_devno == devno) { 171 if (only_if_new && !access(tmp->bid_name, F_OK)) 172 return; 173 dev = blkid_verify(cache, tmp); 174 if (dev && (dev->bid_flags & BLKID_BID_FL_VERIFIED)) 175 break; 176 dev = 0; 177 } 178 } 179 if (dev && dev->bid_devno == devno) 180 goto set_pri; 181 182 /* 183 * Take a quick look at /dev/ptname for the device number. We check 184 * all of the likely device directories. If we don't find it, or if 185 * the stat information doesn't check out, use blkid_devno_to_devname() 186 * to find it via an exhaustive search for the device major/minor. 187 */ 188 for (dir = dirlist; *dir; dir++) { 189 struct stat st; 190 char device[256]; 191 192 sprintf(device, "%s/%s", *dir, ptname); 193 if ((dev = blkid_get_dev(cache, device, BLKID_DEV_FIND)) && 194 dev->bid_devno == devno) 195 goto set_pri; 196 197 if (stat(device, &st) == 0 && S_ISBLK(st.st_mode) && 198 st.st_rdev == devno) { 199 devname = blkid_strdup(device); 200 break; 201 } 202 } 203 /* Do a short-cut scan of /dev/mapper first */ 204 if (!devname) 205 blkid__scan_dir("/dev/mapper", devno, 0, &devname); 206 if (!devname) { 207 devname = blkid_devno_to_devname(devno); 208 if (!devname) 209 return; 210 } 211 dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL); 212 free(devname); 213 214set_pri: 215 if (dev) { 216 if (pri) 217 dev->bid_pri = pri; 218 else if (!strncmp(dev->bid_name, "/dev/mapper/", 11)) { 219 dev->bid_pri = BLKID_PRI_DM; 220 if (is_dm_leaf(ptname)) 221 dev->bid_pri += 5; 222 } else if (!strncmp(ptname, "md", 2)) 223 dev->bid_pri = BLKID_PRI_MD; 224 } 225 return; 226} 227 228#define PROC_PARTITIONS "/proc/partitions" 229#define VG_DIR "/proc/lvm/VGs" 230 231/* 232 * This function initializes the UUID cache with devices from the LVM 233 * proc hierarchy. We currently depend on the names of the LVM 234 * hierarchy giving us the device structure in /dev. (XXX is this a 235 * safe thing to do?) 236 */ 237#ifdef VG_DIR 238static dev_t lvm_get_devno(const char *lvm_device) 239{ 240 FILE *lvf; 241 char buf[1024]; 242 int ma, mi; 243 dev_t ret = 0; 244 245 DBG(DEBUG_DEVNAME, printf("opening %s\n", lvm_device)); 246 if ((lvf = fopen(lvm_device, "r")) == NULL) { 247 DBG(DEBUG_DEVNAME, printf("%s: (%d) %s\n", lvm_device, errno, 248 strerror(errno))); 249 return 0; 250 } 251 252 while (fgets(buf, sizeof(buf), lvf)) { 253 if (sscanf(buf, "device: %d:%d", &ma, &mi) == 2) { 254 ret = makedev(ma, mi); 255 break; 256 } 257 } 258 fclose(lvf); 259 260 return ret; 261} 262 263static void lvm_probe_all(blkid_cache cache, int only_if_new) 264{ 265 DIR *vg_list; 266 struct dirent *vg_iter; 267 int vg_len = strlen(VG_DIR); 268 dev_t dev; 269 270 if ((vg_list = opendir(VG_DIR)) == NULL) 271 return; 272 273 DBG(DEBUG_DEVNAME, printf("probing LVM devices under %s\n", VG_DIR)); 274 275 while ((vg_iter = readdir(vg_list)) != NULL) { 276 DIR *lv_list; 277 char *vdirname; 278 char *vg_name; 279 struct dirent *lv_iter; 280 281 vg_name = vg_iter->d_name; 282 if (!strcmp(vg_name, ".") || !strcmp(vg_name, "..")) 283 continue; 284 vdirname = malloc(vg_len + strlen(vg_name) + 8); 285 if (!vdirname) 286 goto exit; 287 sprintf(vdirname, "%s/%s/LVs", VG_DIR, vg_name); 288 289 lv_list = opendir(vdirname); 290 free(vdirname); 291 if (lv_list == NULL) 292 continue; 293 294 while ((lv_iter = readdir(lv_list)) != NULL) { 295 char *lv_name, *lvm_device; 296 297 lv_name = lv_iter->d_name; 298 if (!strcmp(lv_name, ".") || !strcmp(lv_name, "..")) 299 continue; 300 301 lvm_device = malloc(vg_len + strlen(vg_name) + 302 strlen(lv_name) + 8); 303 if (!lvm_device) { 304 closedir(lv_list); 305 goto exit; 306 } 307 sprintf(lvm_device, "%s/%s/LVs/%s", VG_DIR, vg_name, 308 lv_name); 309 dev = lvm_get_devno(lvm_device); 310 sprintf(lvm_device, "%s/%s", vg_name, lv_name); 311 DBG(DEBUG_DEVNAME, printf("LVM dev %s: devno 0x%04X\n", 312 lvm_device, 313 (unsigned int) dev)); 314 probe_one(cache, lvm_device, dev, BLKID_PRI_LVM, 315 only_if_new); 316 free(lvm_device); 317 } 318 closedir(lv_list); 319 } 320exit: 321 closedir(vg_list); 322} 323#endif 324 325#define PROC_EVMS_VOLUMES "/proc/evms/volumes" 326 327static int 328evms_probe_all(blkid_cache cache, int only_if_new) 329{ 330 char line[100]; 331 int ma, mi, sz, num = 0; 332 FILE *procpt; 333 char device[110]; 334 335 procpt = fopen(PROC_EVMS_VOLUMES, "r"); 336 if (!procpt) 337 return 0; 338 while (fgets(line, sizeof(line), procpt)) { 339 if (sscanf (line, " %d %d %d %*s %*s %[^\n ]", 340 &ma, &mi, &sz, device) != 4) 341 continue; 342 343 DBG(DEBUG_DEVNAME, printf("Checking partition %s (%d, %d)\n", 344 device, ma, mi)); 345 346 probe_one(cache, device, makedev(ma, mi), BLKID_PRI_EVMS, 347 only_if_new); 348 num++; 349 } 350 fclose(procpt); 351 return num; 352} 353 354/* 355 * Read the device data for all available block devices in the system. 356 */ 357static int probe_all(blkid_cache cache, int only_if_new) 358{ 359 FILE *proc; 360 char line[1024]; 361 char ptname0[128], ptname1[128], *ptname = 0; 362 char *ptnames[2]; 363 dev_t devs[2]; 364 int ma, mi; 365 unsigned long long sz; 366 int lens[2] = { 0, 0 }; 367 int which = 0, last = 0; 368 struct list_head *p, *pnext; 369 370 ptnames[0] = ptname0; 371 ptnames[1] = ptname1; 372 373 if (!cache) 374 return -BLKID_ERR_PARAM; 375 376 if (cache->bic_flags & BLKID_BIC_FL_PROBED && 377 time(0) - cache->bic_time < BLKID_PROBE_INTERVAL) 378 return 0; 379 380 blkid_read_cache(cache); 381 evms_probe_all(cache, only_if_new); 382#ifdef VG_DIR 383 lvm_probe_all(cache, only_if_new); 384#endif 385 386 proc = fopen(PROC_PARTITIONS, "r"); 387 if (!proc) 388 return -BLKID_ERR_PROC; 389 390 while (fgets(line, sizeof(line), proc)) { 391 last = which; 392 which ^= 1; 393 ptname = ptnames[which]; 394 395 if (sscanf(line, " %d %d %llu %128[^\n ]", 396 &ma, &mi, &sz, ptname) != 4) 397 continue; 398 devs[which] = makedev(ma, mi); 399 400 DBG(DEBUG_DEVNAME, printf("read partition name %s\n", ptname)); 401 402 /* Skip whole disk devs unless they have no partitions. 403 * If base name of device has changed, also 404 * check previous dev to see if it didn't have a partn. 405 * heuristic: partition name ends in a digit, & partition 406 * names contain whole device name as substring. 407 * 408 * Skip extended partitions. 409 * heuristic: size is 1 410 * 411 * FIXME: skip /dev/{ida,cciss,rd} whole-disk devs 412 */ 413 414 lens[which] = strlen(ptname); 415 416 /* ends in a digit, clearly a partition, so check */ 417 if (isdigit(ptname[lens[which] - 1])) { 418 DBG(DEBUG_DEVNAME, 419 printf("partition dev %s, devno 0x%04X\n", 420 ptname, (unsigned int) devs[which])); 421 422 if (sz > 1) 423 probe_one(cache, ptname, devs[which], 0, 424 only_if_new); 425 lens[which] = 0; /* mark as checked */ 426 } 427 428 /* 429 * If last was a whole disk and we just found a partition 430 * on it, remove the whole-disk dev from the cache if 431 * it exists. 432 */ 433 if (lens[last] && !strncmp(ptnames[last], ptname, lens[last])) { 434 list_for_each_safe(p, pnext, &cache->bic_devs) { 435 blkid_dev tmp; 436 437 /* find blkid dev for the whole-disk devno */ 438 tmp = list_entry(p, struct blkid_struct_dev, 439 bid_devs); 440 if (tmp->bid_devno == devs[last]) { 441 DBG(DEBUG_DEVNAME, 442 printf("freeing %s\n", 443 tmp->bid_name)); 444 blkid_free_dev(tmp); 445 cache->bic_flags |= BLKID_BIC_FL_CHANGED; 446 break; 447 } 448 } 449 lens[last] = 0; 450 } 451 /* 452 * If last was not checked because it looked like a whole-disk 453 * dev, and the device's base name has changed, 454 * check last as well. 455 */ 456 if (lens[last] && strncmp(ptnames[last], ptname, lens[last])) { 457 DBG(DEBUG_DEVNAME, 458 printf("whole dev %s, devno 0x%04X\n", 459 ptnames[last], (unsigned int) devs[last])); 460 probe_one(cache, ptnames[last], devs[last], 0, 461 only_if_new); 462 lens[last] = 0; 463 } 464 } 465 466 /* Handle the last device if it wasn't partitioned */ 467 if (lens[which]) 468 probe_one(cache, ptname, devs[which], 0, only_if_new); 469 470 fclose(proc); 471 blkid_flush_cache(cache); 472 return 0; 473} 474 475int blkid_probe_all(blkid_cache cache) 476{ 477 int ret; 478 479 DBG(DEBUG_PROBE, printf("Begin blkid_probe_all()\n")); 480 ret = probe_all(cache, 0); 481 cache->bic_time = time(0); 482 cache->bic_flags |= BLKID_BIC_FL_PROBED; 483 DBG(DEBUG_PROBE, printf("End blkid_probe_all()\n")); 484 return ret; 485} 486 487int blkid_probe_all_new(blkid_cache cache) 488{ 489 int ret; 490 491 DBG(DEBUG_PROBE, printf("Begin blkid_probe_all_new()\n")); 492 ret = probe_all(cache, 1); 493 DBG(DEBUG_PROBE, printf("End blkid_probe_all_new()\n")); 494 return ret; 495} 496 497 498#ifdef TEST_PROGRAM 499int main(int argc, char **argv) 500{ 501 blkid_cache cache = NULL; 502 int ret; 503 504 blkid_debug_mask = DEBUG_ALL; 505 if (argc != 1) { 506 fprintf(stderr, "Usage: %s\n" 507 "Probe all devices and exit\n", argv[0]); 508 exit(1); 509 } 510 if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) { 511 fprintf(stderr, "%s: error creating cache (%d)\n", 512 argv[0], ret); 513 exit(1); 514 } 515 if (blkid_probe_all(cache) < 0) 516 printf("%s: error probing devices\n", argv[0]); 517 518 blkid_put_cache(cache); 519 return (0); 520} 521#endif 522