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 #ifdef HAVE_UNISTD_H
20 #include <unistd.h>
21 #endif
22 #include <stdlib.h>
23 #include <ctype.h>
24 #include <fcntl.h>
25 #ifdef HAVE_SYS_TYPES_H
26 #include <sys/types.h>
27 #endif
28 #include <dirent.h>
29 #ifdef HAVE_SYS_STAT_H
30 #include <sys/stat.h>
31 #endif
32 #ifdef HAVE_ERRNO_H
33 #include <errno.h>
34 #endif
35 #include <time.h>
36
37 #include "blkidP.h"
38
39 #include "canonicalize.h" /* $(top_srcdir)/include */
40 #include "pathnames.h"
41 #include "sysfs.h"
42 #include "fileutils.h"
43
44 /*
45 * Find a dev struct in the cache by device name, if available.
46 *
47 * If there is no entry with the specified device name, and the create
48 * flag is set, then create an empty device entry.
49 */
50 blkid_dev blkid_get_dev(blkid_cache cache, const char *devname, int flags)
51 {
52 blkid_dev dev = NULL, tmp;
53 struct list_head *p, *pnext;
54 char *cn = NULL;
55
56 if (!cache || !devname)
57 return NULL;
58
59 /* search by name */
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) != 0)
63 continue;
64 dev = tmp;
65 break;
66 }
67
68 /* try canonicalize the name */
69 if (!dev && (cn = canonicalize_path(devname))) {
70 if (strcmp(cn, devname) != 0) {
71 DBG(DEVNAME, ul_debug("search canonical %s", cn));
72 list_for_each(p, &cache->bic_devs) {
73 tmp = list_entry(p, struct blkid_struct_dev, bid_devs);
74 if (strcmp(tmp->bid_name, cn) != 0)
75 continue;
76 dev = tmp;
77
78 /* update name returned by blkid_dev_devname() */
79 free(dev->bid_xname);
80 dev->bid_xname = strdup(devname);
81 break;
82 }
83 } else {
84 free(cn);
85 cn = NULL;
86 }
87 }
88
89 if (!dev && (flags & BLKID_DEV_CREATE)) {
90 if (access(devname, F_OK) < 0)
91 goto done;
92 dev = blkid_new_dev();
93 if (!dev)
94 goto done;
95 dev->bid_time = (uintmax_t)1 << (sizeof(time_t) * 8 - 1);
96 if (cn) {
97 dev->bid_name = cn;
98 dev->bid_xname = strdup(devname);
99 cn = NULL; /* see free() below */
100 } else
101 dev->bid_name = strdup(devname);
102
103 dev->bid_cache = cache;
104 list_add_tail(&dev->bid_devs, &cache->bic_devs);
105 cache->bic_flags |= BLKID_BIC_FL_CHANGED;
106 }
107
108 if (flags & BLKID_DEV_VERIFY) {
109 dev = blkid_verify(cache, dev);
110 if (!dev || !(dev->bid_flags & BLKID_BID_FL_VERIFIED))
111 goto done;
112 /*
113 * If the device is verified, then search the blkid
114 * cache for any entries that match on the type, uuid,
115 * and label, and verify them; if a cache entry can
116 * not be verified, then it's stale and so we remove
117 * it.
118 */
119 list_for_each_safe(p, pnext, &cache->bic_devs) {
120 blkid_dev dev2 = list_entry(p, struct blkid_struct_dev, bid_devs);
121 if (dev2->bid_flags & BLKID_BID_FL_VERIFIED)
122 continue;
123 if (!dev->bid_type || !dev2->bid_type ||
124 strcmp(dev->bid_type, dev2->bid_type) != 0)
125 continue;
126 if (dev->bid_label && dev2->bid_label &&
127 strcmp(dev->bid_label, dev2->bid_label) != 0)
128 continue;
129 if (dev->bid_uuid && dev2->bid_uuid &&
130 strcmp(dev->bid_uuid, dev2->bid_uuid) != 0)
131 continue;
132 if ((dev->bid_label && !dev2->bid_label) ||
133 (!dev->bid_label && dev2->bid_label) ||
134 (dev->bid_uuid && !dev2->bid_uuid) ||
135 (!dev->bid_uuid && dev2->bid_uuid))
136 continue;
137 dev2 = blkid_verify(cache, dev2);
138 if (dev2 && !(dev2->bid_flags & BLKID_BID_FL_VERIFIED))
139 blkid_free_dev(dev2);
140 }
141 }
142 done:
143 if (dev)
144 DBG(DEVNAME, ul_debug("%s requested, found %s in cache", devname, dev->bid_name));
145 free(cn);
146 return dev;
147 }
148
149 /* Directories where we will try to search for device names */
150 static const char *dirlist[] = { "/dev", "/devfs", "/devices", NULL };
151
152 /*
153 * Return 1 if the device is a device-mapper 'leaf' node
154 * not holding any other devices in its hierarchy.
155 */
156 static int is_dm_leaf(const char *devname)
157 {
158 DIR *dir;
159 char path[NAME_MAX + 18 + 1];
160 int ret;
161
162 snprintf(path, sizeof(path), "/sys/block/%s/holders", devname);
163 if ((dir = opendir(path)) == NULL)
164 return 0;
165
166 ret = xreaddir(dir) == NULL ? 1 : 0; /* 'leaf' has no entries */
167
168 closedir(dir);
169 return ret;
170 }
171
172 /*
173 * Probe a single block device to add to the device cache.
174 */
175 static void probe_one(blkid_cache cache, const char *ptname,
176 dev_t devno, int pri, int only_if_new, int removable)
177 {
178 blkid_dev dev = NULL;
179 struct list_head *p, *pnext;
180 const char **dir;
181 char *devname = NULL;
182
183 /* See if we already have this device number in the cache. */
184 list_for_each_safe(p, pnext, &cache->bic_devs) {
185 blkid_dev tmp = list_entry(p, struct blkid_struct_dev,
186 bid_devs);
187 if (tmp->bid_devno == devno) {
188 if (only_if_new && !access(tmp->bid_name, F_OK))
189 return;
190 dev = blkid_verify(cache, tmp);
191 if (dev && (dev->bid_flags & BLKID_BID_FL_VERIFIED))
192 break;
193 dev = NULL;
194 }
195 }
196 if (dev && dev->bid_devno == devno)
197 goto set_pri;
198
199 /* Try to translate private device-mapper dm-<N> names
200 * to standard /dev/mapper/<name>.
201 */
202 if (!strncmp(ptname, "dm-", 3) && isdigit(ptname[3])) {
203 devname = canonicalize_dm_name(ptname);
204 if (!devname)
205 blkid__scan_dir("/dev/mapper", devno, NULL, &devname);
206 if (devname)
207 goto get_dev;
208 }
209
210 /*
211 * Take a quick look at /dev/ptname for the device number. We check
212 * all of the likely device directories. If we don't find it, or if
213 * the stat information doesn't check out, use blkid_devno_to_devname()
214 * to find it via an exhaustive search for the device major/minor.
215 */
216 for (dir = dirlist; *dir; dir++) {
217 struct stat st;
218 char device[256];
219
220 snprintf(device, sizeof(device), "%s/%s", *dir, ptname);
221 if ((dev = blkid_get_dev(cache, device, BLKID_DEV_FIND)) &&
222 dev->bid_devno == devno)
223 goto set_pri;
224
225 if (stat(device, &st) == 0 &&
226 (S_ISBLK(st.st_mode) ||
227 (S_ISCHR(st.st_mode) && !strncmp(ptname, "ubi", 3))) &&
228 st.st_rdev == devno) {
229 devname = strdup(device);
230 goto get_dev;
231 }
232 }
233 /* Do a short-cut scan of /dev/mapper first */
234 if (!devname)
235 blkid__scan_dir("/dev/mapper", devno, NULL, &devname);
236 if (!devname) {
237 devname = blkid_devno_to_devname(devno);
238 if (!devname)
239 return;
240 }
241
242 get_dev:
243 dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
244 free(devname);
245
246 set_pri:
247 if (dev) {
248 if (pri)
249 dev->bid_pri = pri;
250 else if (!strncmp(dev->bid_name, "/dev/mapper/", 12)) {
251 dev->bid_pri = BLKID_PRI_DM;
252 if (is_dm_leaf(ptname))
253 dev->bid_pri += 5;
254 } else if (!strncmp(ptname, "md", 2))
255 dev->bid_pri = BLKID_PRI_MD;
256 if (removable)
257 dev->bid_flags |= BLKID_BID_FL_REMOVABLE;
258 }
259 }
260
261 #define PROC_PARTITIONS "/proc/partitions"
262 #define VG_DIR "/proc/lvm/VGs"
263
264 /*
265 * This function initializes the UUID cache with devices from the LVM
266 * proc hierarchy. We currently depend on the names of the LVM
267 * hierarchy giving us the device structure in /dev. (XXX is this a
268 * safe thing to do?)
269 */
270 #ifdef VG_DIR
271 static dev_t lvm_get_devno(const char *lvm_device)
272 {
273 FILE *lvf;
274 char buf[1024];
275 int ma, mi;
276 dev_t ret = 0;
277
278 DBG(DEVNAME, ul_debug("opening %s", lvm_device));
279 if ((lvf = fopen(lvm_device, "r" UL_CLOEXECSTR)) == NULL) {
280 DBG(DEVNAME, ul_debug("%s: (%d) %m", lvm_device, errno));
281 return 0;
282 }
283
284 while (fgets(buf, sizeof(buf), lvf)) {
285 if (sscanf(buf, "device: %d:%d", &ma, &mi) == 2) {
286 ret = makedev(ma, mi);
287 break;
288 }
289 }
290 fclose(lvf);
291
292 return ret;
293 }
294
295 static void lvm_probe_all(blkid_cache cache, int only_if_new)
296 {
297 DIR *vg_list;
298 struct dirent *vg_iter;
299 int vg_len = strlen(VG_DIR);
300 dev_t dev;
301
302 if ((vg_list = opendir(VG_DIR)) == NULL)
303 return;
304
305 DBG(DEVNAME, ul_debug("probing LVM devices under %s", VG_DIR));
306
307 while ((vg_iter = readdir(vg_list)) != NULL) {
308 DIR *lv_list;
309 char *vdirname;
310 char *vg_name;
311 struct dirent *lv_iter;
312 size_t len;
313
314 vg_name = vg_iter->d_name;
315 if (!strcmp(vg_name, ".") || !strcmp(vg_name, ".."))
316 continue;
317 len = vg_len + strlen(vg_name) + 8;
318 vdirname = malloc(len);
319 if (!vdirname)
320 goto exit;
321 snprintf(vdirname, len, "%s/%s/LVs", VG_DIR, vg_name);
322
323 lv_list = opendir(vdirname);
324 free(vdirname);
325 if (lv_list == NULL)
326 continue;
327
328 while ((lv_iter = readdir(lv_list)) != NULL) {
329 char *lv_name, *lvm_device;
330
331 lv_name = lv_iter->d_name;
332 if (!strcmp(lv_name, ".") || !strcmp(lv_name, ".."))
333 continue;
334
335 len = vg_len + strlen(vg_name) + strlen(lv_name) + 8;
336 lvm_device = malloc(len);
337 if (!lvm_device) {
338 closedir(lv_list);
339 goto exit;
340 }
341 snprintf(lvm_device, len, "%s/%s/LVs/%s", VG_DIR, vg_name,
342 lv_name);
343 dev = lvm_get_devno(lvm_device);
344 snprintf(lvm_device, len, "%s/%s", vg_name, lv_name);
345 DBG(DEVNAME, ul_debug("Probe LVM dev %s: devno 0x%04X",
346 lvm_device,
347 (unsigned int) dev));
348 probe_one(cache, lvm_device, dev, BLKID_PRI_LVM,
349 only_if_new, 0);
350 free(lvm_device);
351 }
352 closedir(lv_list);
353 }
354 exit:
355 closedir(vg_list);
356 }
357 #endif
358
359 static void
360 ubi_probe_all(blkid_cache cache, int only_if_new)
361 {
362 const char **dirname;
363
364 for (dirname = dirlist; *dirname; dirname++) {
365 DIR *dir;
366 struct dirent *iter;
367
368 DBG(DEVNAME, ul_debug("probing UBI volumes under %s",
369 *dirname));
370
371 dir = opendir(*dirname);
372 if (dir == NULL)
373 continue ;
374
375 while ((iter = readdir(dir)) != NULL) {
376 char *name;
377 struct stat st;
378 dev_t dev;
379
380 name = iter->d_name;
381 #ifdef _DIRENT_HAVE_D_TYPE
382 if (iter->d_type != DT_UNKNOWN &&
383 iter->d_type != DT_CHR && iter->d_type != DT_LNK)
384 continue;
385 #endif
386 if (!strcmp(name, ".") || !strcmp(name, "..") ||
387 !strstr(name, "ubi"))
388 continue;
389 if (!strcmp(name, "ubi_ctrl"))
390 continue;
391 if (fstatat(dirfd(dir), name, &st, 0))
392 continue;
393
394 dev = st.st_rdev;
395
396 if (!S_ISCHR(st.st_mode) || !minor(dev))
397 continue;
398 DBG(DEVNAME, ul_debug("Probe UBI vol %s/%s: devno 0x%04X",
399 *dirname, name, (int) dev));
400 probe_one(cache, name, dev, BLKID_PRI_UBI, only_if_new, 0);
401 }
402 closedir(dir);
403 }
404 }
405
406 /*
407 * This function uses /sys to read all block devices in way compatible with
408 * /proc/partitions (like the original libblkid implementation)
409 */
410 static int
411 sysfs_probe_all(blkid_cache cache, int only_if_new, int only_removable)
412 {
413 DIR *sysfs;
414 struct dirent *dev;
415
416 sysfs = opendir(_PATH_SYS_BLOCK);
417 if (!sysfs)
418 return -BLKID_ERR_SYSFS;
419
420 DBG(DEVNAME, ul_debug(" probe /sys/block"));
421
422 /* scan /sys/block */
423 while ((dev = xreaddir(sysfs))) {
424 DIR *dir = NULL;
425 dev_t devno;
426 size_t nparts = 0;
427 unsigned int maxparts = 0, removable = 0;
428 struct dirent *part;
429 struct path_cxt *pc = NULL;
430 uint64_t size = 0;
431
432 DBG(DEVNAME, ul_debug("checking %s", dev->d_name));
433
434 devno = sysfs_devname_to_devno(dev->d_name);
435 if (!devno)
436 goto next;
437 pc = ul_new_sysfs_path(devno, NULL, NULL);
438 if (!pc)
439 goto next;
440
441 if (ul_path_read_u64(pc, &size, "size") != 0)
442 size = 0;
443 if (ul_path_read_u32(pc, &removable, "removable") != 0)
444 removable = 0;
445
446 /* ignore empty devices */
447 if (!size)
448 goto next;
449
450 /* accept removable if only removable requested */
451 if (only_removable) {
452 if (!removable)
453 goto next;
454
455 /* emulate /proc/partitions
456 * -- ignore empty devices and non-partitionable removable devices */
457 } else {
458 if (ul_path_read_u32(pc, &maxparts, "ext_range") != 0)
459 maxparts = 0;
460 if (!maxparts && removable)
461 goto next;
462 }
463
464 DBG(DEVNAME, ul_debug("read device name %s", dev->d_name));
465
466 dir = ul_path_opendir(pc, NULL);
467 if (!dir)
468 goto next;
469
470 /* read /sys/block/<name>/ do get partitions */
471 while ((part = xreaddir(dir))) {
472 dev_t partno;
473
474 if (!sysfs_blkdev_is_partition_dirent(dir, part, dev->d_name))
475 continue;
476
477 /* ignore extended partitions
478 * -- recount size to blocks like /proc/partitions */
479 if (ul_path_readf_u64(pc, &size, "%s/size", part->d_name) == 0
480 && (size >> 1) == 1)
481 continue;
482 partno = __sysfs_devname_to_devno(NULL, part->d_name, dev->d_name);
483 if (!partno)
484 continue;
485
486 DBG(DEVNAME, ul_debug(" Probe partition dev %s, devno 0x%04X",
487 part->d_name, (unsigned int) partno));
488 nparts++;
489 probe_one(cache, part->d_name, partno, 0, only_if_new, 0);
490 }
491
492 if (!nparts) {
493 /* add non-partitioned whole disk to cache */
494 DBG(DEVNAME, ul_debug(" Probe whole dev %s, devno 0x%04X",
495 dev->d_name, (unsigned int) devno));
496 probe_one(cache, dev->d_name, devno, 0, only_if_new, 0);
497 } else {
498 /* remove partitioned whole-disk from cache */
499 struct list_head *p, *pnext;
500
501 list_for_each_safe(p, pnext, &cache->bic_devs) {
502 blkid_dev tmp = list_entry(p, struct blkid_struct_dev,
503 bid_devs);
504 if (tmp->bid_devno == devno) {
505 DBG(DEVNAME, ul_debug(" freeing %s", tmp->bid_name));
506 blkid_free_dev(tmp);
507 cache->bic_flags |= BLKID_BIC_FL_CHANGED;
508 break;
509 }
510 }
511 }
512 next:
513 if (dir)
514 closedir(dir);
515 if (pc)
516 ul_unref_path(pc);
517 }
518
519 closedir(sysfs);
520 return 0;
521 }
522
523 /*
524 * Read the device data for all available block devices in the system.
525 */
526 static int probe_all(blkid_cache cache, int only_if_new, int update_interval)
527 {
528 int rc;
529
530 if (!cache)
531 return -BLKID_ERR_PARAM;
532
533 if (cache->bic_flags & BLKID_BIC_FL_PROBED &&
534 time(NULL) - cache->bic_time < BLKID_PROBE_INTERVAL) {
535 DBG(PROBE, ul_debug("don't re-probe [delay < %d]", BLKID_PROBE_INTERVAL));
536 return 0;
537 }
538
539 blkid_read_cache(cache);
540 #ifdef VG_DIR
541 lvm_probe_all(cache, only_if_new);
542 #endif
543 ubi_probe_all(cache, only_if_new);
544
545 rc = sysfs_probe_all(cache, only_if_new, 0);
546
547 /* Don't mark the change as "probed" if /sys not avalable */
548 if (update_interval && rc == 0) {
549 cache->bic_time = time(NULL);
550 cache->bic_flags |= BLKID_BIC_FL_PROBED;
551 }
552
553 blkid_flush_cache(cache);
554 return 0;
555 }
556
557 /**
558 * blkid_probe_all:
559 * @cache: cache handler
560 *
561 * Probes all block devices.
562 *
563 * Returns: 0 on success, or number less than zero in case of error.
564 */
565 int blkid_probe_all(blkid_cache cache)
566 {
567 int ret;
568
569 DBG(PROBE, ul_debug("Begin blkid_probe_all()"));
570 ret = probe_all(cache, 0, 1);
571 DBG(PROBE, ul_debug("End blkid_probe_all() [rc=%d]", ret));
572 return ret;
573 }
574
575 /**
576 * blkid_probe_all_new:
577 * @cache: cache handler
578 *
579 * Probes all new block devices.
580 *
581 * Returns: 0 on success, or number less than zero in case of error.
582 */
583 int blkid_probe_all_new(blkid_cache cache)
584 {
585 int ret;
586
587 DBG(PROBE, ul_debug("Begin blkid_probe_all_new()"));
588 ret = probe_all(cache, 1, 0);
589 DBG(PROBE, ul_debug("End blkid_probe_all_new() [rc=%d]", ret));
590 return ret;
591 }
592
593 /**
594 * blkid_probe_all_removable:
595 * @cache: cache handler
596 *
597 * The libblkid probing is based on devices from /proc/partitions by default.
598 * This file usually does not contain removable devices (e.g. CDROMs) and this kind
599 * of devices are invisible for libblkid.
600 *
601 * This function adds removable block devices to @cache (probing is based on
602 * information from the /sys directory). Don't forget that removable devices
603 * (floppies, CDROMs, ...) could be pretty slow. It's very bad idea to call
604 * this function by default.
605 *
606 * Note that devices which were detected by this function won't be written to
607 * blkid.tab cache file.
608 *
609 * Returns: 0 on success, or number less than zero in case of error.
610 */
611 int blkid_probe_all_removable(blkid_cache cache)
612 {
613 int ret;
614
615 DBG(PROBE, ul_debug("Begin blkid_probe_all_removable()"));
616 ret = sysfs_probe_all(cache, 0, 1);
617 DBG(PROBE, ul_debug("End blkid_probe_all_removable() [rc=%d]", ret));
618 return ret;
619 }
620
621 #ifdef TEST_PROGRAM
622 int main(int argc, char **argv)
623 {
624 blkid_cache cache = NULL;
625 int ret;
626
627 blkid_init_debug(BLKID_DEBUG_ALL);
628 if (argc != 1) {
629 fprintf(stderr, "Usage: %s\n"
630 "Probe all devices and exit\n", argv[0]);
631 exit(1);
632 }
633 if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
634 fprintf(stderr, "%s: error creating cache (%d)\n",
635 argv[0], ret);
636 exit(1);
637 }
638 if (blkid_probe_all(cache) < 0)
639 printf("%s: error probing devices\n", argv[0]);
640
641 if (blkid_probe_all_removable(cache) < 0)
642 printf("%s: error probing removable devices\n", argv[0]);
643
644 blkid_put_cache(cache);
645 return (0);
646 }
647 #endif