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
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 */
blkid_get_dev(blkid_cache cache,const char * devname,int flags)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 char *cn = NULL;
54
55 if (!cache || !devname)
56 return NULL;
57
58 /* search by name */
59 list_for_each(p, &cache->bic_devs) {
60 tmp = list_entry(p, struct blkid_struct_dev, bid_devs);
61 if (strcmp(tmp->bid_name, devname) != 0)
62 continue;
63 dev = tmp;
64 break;
65 }
66
67 /* try canonicalize the name */
68 if (!dev && (cn = canonicalize_path(devname))) {
69 if (strcmp(cn, devname) != 0) {
70 DBG(DEVNAME, ul_debug("search canonical %s", cn));
71 list_for_each(p, &cache->bic_devs) {
72 tmp = list_entry(p, struct blkid_struct_dev, bid_devs);
73 if (strcmp(tmp->bid_name, cn) != 0)
74 continue;
75 dev = tmp;
76
77 /* update name returned by blkid_dev_devname() */
78 free(dev->bid_xname);
79 dev->bid_xname = strdup(devname);
80 break;
81 }
82 } else {
83 free(cn);
84 cn = NULL;
85 }
86 }
87
88 if (!dev && (flags & BLKID_DEV_CREATE)) {
89 if (access(devname, F_OK) < 0)
90 goto done;
91 dev = blkid_new_dev();
92 if (!dev)
93 goto done;
94 dev->bid_time = INT_MIN;
95 if (cn) {
96 dev->bid_name = cn;
97 dev->bid_xname = strdup(devname);
98 cn = NULL; /* see free() below */
99 } else
100 dev->bid_name = strdup(devname);
101
102 dev->bid_cache = cache;
103 list_add_tail(&dev->bid_devs, &cache->bic_devs);
104 cache->bic_flags |= BLKID_BIC_FL_CHANGED;
105 }
106
107 if (flags & BLKID_DEV_VERIFY) {
108 dev = blkid_verify(cache, dev);
109 if (!dev || !(dev->bid_flags & BLKID_BID_FL_VERIFIED))
110 goto done;
111 /*
112 * If the device is verified, then search the blkid
113 * cache for any entries that match on the type, uuid,
114 * and label, and verify them; if a cache entry can
115 * not be verified, then it's stale and so we remove
116 * it.
117 */
118 list_for_each_safe(p, pnext, &cache->bic_devs) {
119 blkid_dev dev2 = list_entry(p, struct blkid_struct_dev, bid_devs);
120 if (dev2->bid_flags & BLKID_BID_FL_VERIFIED)
121 continue;
122 if (!dev->bid_type || !dev2->bid_type ||
123 strcmp(dev->bid_type, dev2->bid_type) != 0)
124 continue;
125 if (dev->bid_label && dev2->bid_label &&
126 strcmp(dev->bid_label, dev2->bid_label) != 0)
127 continue;
128 if (dev->bid_uuid && dev2->bid_uuid &&
129 strcmp(dev->bid_uuid, dev2->bid_uuid) != 0)
130 continue;
131 if ((dev->bid_label && !dev2->bid_label) ||
132 (!dev->bid_label && dev2->bid_label) ||
133 (dev->bid_uuid && !dev2->bid_uuid) ||
134 (!dev->bid_uuid && dev2->bid_uuid))
135 continue;
136 dev2 = blkid_verify(cache, dev2);
137 if (dev2 && !(dev2->bid_flags & BLKID_BID_FL_VERIFIED))
138 blkid_free_dev(dev2);
139 }
140 }
141 done:
142 if (dev)
143 DBG(DEVNAME, ul_debug("%s requested, found %s in cache", devname, dev->bid_name));
144 free(cn);
145 return dev;
146 }
147
148 /* Directories where we will try to search for device names */
149 static const char *dirlist[] = { "/dev", "/devfs", "/devices", NULL };
150
is_dm_leaf(const char * devname)151 static int is_dm_leaf(const char *devname)
152 {
153 struct dirent *de, *d_de;
154 DIR *dir, *d_dir;
155 char path[NAME_MAX + 18 + 1];
156 int ret = 1;
157
158 if ((dir = opendir("/sys/block")) == NULL)
159 return 0;
160 while ((de = readdir(dir)) != NULL) {
161 if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..") ||
162 !strcmp(de->d_name, devname) ||
163 strncmp(de->d_name, "dm-", 3) != 0 ||
164 strlen(de->d_name) > sizeof(path)-32)
165 continue;
166 sprintf(path, "/sys/block/%s/slaves", de->d_name);
167 if ((d_dir = opendir(path)) == NULL)
168 continue;
169 while ((d_de = readdir(d_dir)) != NULL) {
170 if (!strcmp(d_de->d_name, devname)) {
171 ret = 0;
172 break;
173 }
174 }
175 closedir(d_dir);
176 if (!ret)
177 break;
178 }
179 closedir(dir);
180 return ret;
181 }
182
183 /*
184 * Probe a single block device to add to the device cache.
185 */
probe_one(blkid_cache cache,const char * ptname,dev_t devno,int pri,int only_if_new,int removable)186 static void probe_one(blkid_cache cache, const char *ptname,
187 dev_t devno, int pri, int only_if_new, int removable)
188 {
189 blkid_dev dev = NULL;
190 struct list_head *p, *pnext;
191 const char **dir;
192 char *devname = NULL;
193
194 /* See if we already have this device number in the cache. */
195 list_for_each_safe(p, pnext, &cache->bic_devs) {
196 blkid_dev tmp = list_entry(p, struct blkid_struct_dev,
197 bid_devs);
198 if (tmp->bid_devno == devno) {
199 if (only_if_new && !access(tmp->bid_name, F_OK))
200 return;
201 dev = blkid_verify(cache, tmp);
202 if (dev && (dev->bid_flags & BLKID_BID_FL_VERIFIED))
203 break;
204 dev = NULL;
205 }
206 }
207 if (dev && dev->bid_devno == devno)
208 goto set_pri;
209
210 /* Try to translate private device-mapper dm-<N> names
211 * to standard /dev/mapper/<name>.
212 */
213 if (!strncmp(ptname, "dm-", 3) && isdigit(ptname[3])) {
214 devname = canonicalize_dm_name(ptname);
215 if (!devname)
216 blkid__scan_dir("/dev/mapper", devno, NULL, &devname);
217 if (devname)
218 goto get_dev;
219 }
220
221 /*
222 * Take a quick look at /dev/ptname for the device number. We check
223 * all of the likely device directories. If we don't find it, or if
224 * the stat information doesn't check out, use blkid_devno_to_devname()
225 * to find it via an exhaustive search for the device major/minor.
226 */
227 for (dir = dirlist; *dir; dir++) {
228 struct stat st;
229 char device[256];
230
231 snprintf(device, sizeof(device), "%s/%s", *dir, ptname);
232 if ((dev = blkid_get_dev(cache, device, BLKID_DEV_FIND)) &&
233 dev->bid_devno == devno)
234 goto set_pri;
235
236 if (stat(device, &st) == 0 &&
237 (S_ISBLK(st.st_mode) ||
238 (S_ISCHR(st.st_mode) && !strncmp(ptname, "ubi", 3))) &&
239 st.st_rdev == devno) {
240 devname = strdup(device);
241 goto get_dev;
242 }
243 }
244 /* Do a short-cut scan of /dev/mapper first */
245 if (!devname)
246 blkid__scan_dir("/dev/mapper", devno, NULL, &devname);
247 if (!devname) {
248 devname = blkid_devno_to_devname(devno);
249 if (!devname)
250 return;
251 }
252
253 get_dev:
254 dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
255 free(devname);
256
257 set_pri:
258 if (dev) {
259 if (pri)
260 dev->bid_pri = pri;
261 else if (!strncmp(dev->bid_name, "/dev/mapper/", 12)) {
262 dev->bid_pri = BLKID_PRI_DM;
263 if (is_dm_leaf(ptname))
264 dev->bid_pri += 5;
265 } else if (!strncmp(ptname, "md", 2))
266 dev->bid_pri = BLKID_PRI_MD;
267 if (removable)
268 dev->bid_flags |= BLKID_BID_FL_REMOVABLE;
269 }
270 }
271
272 #define PROC_PARTITIONS "/proc/partitions"
273 #define VG_DIR "/proc/lvm/VGs"
274
275 /*
276 * This function initializes the UUID cache with devices from the LVM
277 * proc hierarchy. We currently depend on the names of the LVM
278 * hierarchy giving us the device structure in /dev. (XXX is this a
279 * safe thing to do?)
280 */
281 #ifdef VG_DIR
lvm_get_devno(const char * lvm_device)282 static dev_t lvm_get_devno(const char *lvm_device)
283 {
284 FILE *lvf;
285 char buf[1024];
286 int ma, mi;
287 dev_t ret = 0;
288
289 DBG(DEVNAME, ul_debug("opening %s", lvm_device));
290 if ((lvf = fopen(lvm_device, "r" UL_CLOEXECSTR)) == NULL) {
291 DBG(DEVNAME, ul_debug("%s: (%d) %m", lvm_device, errno));
292 return 0;
293 }
294
295 while (fgets(buf, sizeof(buf), lvf)) {
296 if (sscanf(buf, "device: %d:%d", &ma, &mi) == 2) {
297 ret = makedev(ma, mi);
298 break;
299 }
300 }
301 fclose(lvf);
302
303 return ret;
304 }
305
lvm_probe_all(blkid_cache cache,int only_if_new)306 static void lvm_probe_all(blkid_cache cache, int only_if_new)
307 {
308 DIR *vg_list;
309 struct dirent *vg_iter;
310 int vg_len = strlen(VG_DIR);
311 dev_t dev;
312
313 if ((vg_list = opendir(VG_DIR)) == NULL)
314 return;
315
316 DBG(DEVNAME, ul_debug("probing LVM devices under %s", VG_DIR));
317
318 while ((vg_iter = readdir(vg_list)) != NULL) {
319 DIR *lv_list;
320 char *vdirname;
321 char *vg_name;
322 struct dirent *lv_iter;
323
324 vg_name = vg_iter->d_name;
325 if (!strcmp(vg_name, ".") || !strcmp(vg_name, ".."))
326 continue;
327 vdirname = malloc(vg_len + strlen(vg_name) + 8);
328 if (!vdirname)
329 goto exit;
330 sprintf(vdirname, "%s/%s/LVs", VG_DIR, vg_name);
331
332 lv_list = opendir(vdirname);
333 free(vdirname);
334 if (lv_list == NULL)
335 continue;
336
337 while ((lv_iter = readdir(lv_list)) != NULL) {
338 char *lv_name, *lvm_device;
339
340 lv_name = lv_iter->d_name;
341 if (!strcmp(lv_name, ".") || !strcmp(lv_name, ".."))
342 continue;
343
344 lvm_device = malloc(vg_len + strlen(vg_name) +
345 strlen(lv_name) + 8);
346 if (!lvm_device) {
347 closedir(lv_list);
348 goto exit;
349 }
350 sprintf(lvm_device, "%s/%s/LVs/%s", VG_DIR, vg_name,
351 lv_name);
352 dev = lvm_get_devno(lvm_device);
353 sprintf(lvm_device, "%s/%s", vg_name, lv_name);
354 DBG(DEVNAME, ul_debug("LVM dev %s: devno 0x%04X",
355 lvm_device,
356 (unsigned int) dev));
357 probe_one(cache, lvm_device, dev, BLKID_PRI_LVM,
358 only_if_new, 0);
359 free(lvm_device);
360 }
361 closedir(lv_list);
362 }
363 exit:
364 closedir(vg_list);
365 }
366 #endif
367
368 #define PROC_EVMS_VOLUMES "/proc/evms/volumes"
369
370 static int
evms_probe_all(blkid_cache cache,int only_if_new)371 evms_probe_all(blkid_cache cache, int only_if_new)
372 {
373 char line[100];
374 int ma, mi, sz, num = 0;
375 FILE *procpt;
376 char device[110];
377
378 procpt = fopen(PROC_EVMS_VOLUMES, "r" UL_CLOEXECSTR);
379 if (!procpt)
380 return 0;
381 while (fgets(line, sizeof(line), procpt)) {
382 if (sscanf (line, " %d %d %d %*s %*s %[^\n ]",
383 &ma, &mi, &sz, device) != 4)
384 continue;
385
386 DBG(DEVNAME, ul_debug("Checking partition %s (%d, %d)",
387 device, ma, mi));
388
389 probe_one(cache, device, makedev(ma, mi), BLKID_PRI_EVMS,
390 only_if_new, 0);
391 num++;
392 }
393 fclose(procpt);
394 return num;
395 }
396
397 static void
ubi_probe_all(blkid_cache cache,int only_if_new)398 ubi_probe_all(blkid_cache cache, int only_if_new)
399 {
400 const char **dirname;
401
402 for (dirname = dirlist; *dirname; dirname++) {
403 DIR *dir;
404 struct dirent *iter;
405
406 DBG(DEVNAME, ul_debug("probing UBI volumes under %s",
407 *dirname));
408
409 dir = opendir(*dirname);
410 if (dir == NULL)
411 continue ;
412
413 while ((iter = readdir(dir)) != NULL) {
414 char *name;
415 struct stat st;
416 dev_t dev;
417
418 name = iter->d_name;
419 #ifdef _DIRENT_HAVE_D_TYPE
420 if (iter->d_type != DT_UNKNOWN &&
421 iter->d_type != DT_CHR && iter->d_type != DT_LNK)
422 continue;
423 #endif
424 if (!strcmp(name, ".") || !strcmp(name, "..") ||
425 !strstr(name, "ubi"))
426 continue;
427 if (!strcmp(name, "ubi_ctrl"))
428 continue;
429 if (fstatat(dirfd(dir), name, &st, 0))
430 continue;
431
432 dev = st.st_rdev;
433
434 if (!S_ISCHR(st.st_mode) || !minor(dev))
435 continue;
436 DBG(DEVNAME, ul_debug("UBI vol %s/%s: devno 0x%04X",
437 *dirname, name, (int) dev));
438 probe_one(cache, name, dev, BLKID_PRI_UBI, only_if_new, 0);
439 }
440 closedir(dir);
441 }
442 }
443
444 /*
445 * Read the device data for all available block devices in the system.
446 */
probe_all(blkid_cache cache,int only_if_new)447 static int probe_all(blkid_cache cache, int only_if_new)
448 {
449 FILE *proc;
450 char line[1024];
451 char ptname0[128 + 1], ptname1[128 + 1], *ptname = NULL;
452 char *ptnames[2];
453 dev_t devs[2] = { 0, 0 };
454 int iswhole[2] = { 0, 0 };
455 int ma, mi;
456 unsigned long long sz;
457 int lens[2] = { 0, 0 };
458 int which = 0, last = 0;
459 struct list_head *p, *pnext;
460
461 ptnames[0] = ptname0;
462 ptnames[1] = ptname1;
463
464 if (!cache)
465 return -BLKID_ERR_PARAM;
466
467 if (cache->bic_flags & BLKID_BIC_FL_PROBED &&
468 time(NULL) - cache->bic_time < BLKID_PROBE_INTERVAL)
469 return 0;
470
471 blkid_read_cache(cache);
472 evms_probe_all(cache, only_if_new);
473 #ifdef VG_DIR
474 lvm_probe_all(cache, only_if_new);
475 #endif
476 ubi_probe_all(cache, only_if_new);
477
478 proc = fopen(PROC_PARTITIONS, "r" UL_CLOEXECSTR);
479 if (!proc)
480 return -BLKID_ERR_PROC;
481
482 while (fgets(line, sizeof(line), proc)) {
483 last = which;
484 which ^= 1;
485 ptname = ptnames[which];
486
487 if (sscanf(line, " %d %d %llu %128[^\n ]",
488 &ma, &mi, &sz, ptname) != 4)
489 continue;
490 devs[which] = makedev(ma, mi);
491
492 DBG(DEVNAME, ul_debug("read device name %s", ptname));
493
494 /* Skip whole disk devs unless they have no partitions.
495 * If base name of device has changed, also
496 * check previous dev to see if it didn't have a partn.
497 * heuristic: partition name ends in a digit, & partition
498 * names contain whole device name as substring.
499 *
500 * Skip extended partitions.
501 * heuristic: size is 1
502 */
503
504 lens[which] = strlen(ptname);
505 iswhole[which] = sysfs_devno_is_wholedisk(devs[which]);
506
507 /* probably partition, so check */
508 if (!iswhole[which]) {
509 DBG(DEVNAME, ul_debug(" partition dev %s, devno 0x%04X",
510 ptname, (unsigned int) devs[which]));
511
512 if (sz > 1)
513 probe_one(cache, ptname, devs[which], 0,
514 only_if_new, 0);
515 lens[which] = 0; /* mark as checked */
516 }
517
518 /*
519 * If last was a whole disk and we just found a partition
520 * on it, remove the whole-disk dev from the cache if
521 * it exists.
522 */
523 if (lens[last] && iswhole[last]
524 && !strncmp(ptnames[last], ptname, lens[last])) {
525
526 list_for_each_safe(p, pnext, &cache->bic_devs) {
527 blkid_dev tmp;
528
529 /* find blkid dev for the whole-disk devno */
530 tmp = list_entry(p, struct blkid_struct_dev,
531 bid_devs);
532 if (tmp->bid_devno == devs[last]) {
533 DBG(DEVNAME, ul_debug(" freeing %s",
534 tmp->bid_name));
535 blkid_free_dev(tmp);
536 cache->bic_flags |= BLKID_BIC_FL_CHANGED;
537 break;
538 }
539 }
540 lens[last] = 0; /* mark as checked */
541 }
542 /*
543 * If last was not checked because it looked like a whole-disk
544 * dev, and the device's base name has changed,
545 * check last as well.
546 */
547 if (lens[last] && strncmp(ptnames[last], ptname, lens[last]) != 0) {
548 DBG(DEVNAME, ul_debug(" whole dev %s, devno 0x%04X",
549 ptnames[last], (unsigned int) devs[last]));
550 probe_one(cache, ptnames[last], devs[last], 0,
551 only_if_new, 0);
552
553 lens[last] = 0; /* mark as checked */
554 }
555 }
556
557 /* Handle the last device if it wasn't partitioned */
558 if (lens[which])
559 probe_one(cache, ptname, devs[which], 0, only_if_new, 0);
560
561 fclose(proc);
562 blkid_flush_cache(cache);
563 return 0;
564 }
565
566 /* Don't use it by default -- it's pretty slow (because cdroms, floppy, ...)
567 */
probe_all_removable(blkid_cache cache)568 static int probe_all_removable(blkid_cache cache)
569 {
570 struct path_cxt *pc;
571 DIR *dir;
572 struct dirent *d;
573
574 if (!cache)
575 return -BLKID_ERR_PARAM;
576
577 dir = opendir(_PATH_SYS_BLOCK);
578 if (!dir)
579 return -BLKID_ERR_PROC;
580
581 pc = ul_new_path(NULL);
582
583 while((d = readdir(dir))) {
584 int removable = 0;
585 dev_t devno;
586
587 #ifdef _DIRENT_HAVE_D_TYPE
588 if (d->d_type != DT_UNKNOWN && d->d_type != DT_LNK)
589 continue;
590 #endif
591 if (d->d_name[0] == '.' &&
592 ((d->d_name[1] == 0) ||
593 ((d->d_name[1] == '.') && (d->d_name[2] == 0))))
594 continue;
595
596 devno = sysfs_devname_to_devno(d->d_name);
597 if (!devno)
598 continue;
599
600 if (sysfs_blkdev_init_path(pc, devno, NULL) == 0
601 && ul_path_read_s32(pc, &removable, "removable") != 0)
602 removable = 0;
603
604 if (removable)
605 probe_one(cache, d->d_name, devno, 0, 0, 1);
606 }
607
608 ul_unref_path(pc);
609 closedir(dir);
610 return 0;
611 }
612
613
614 /**
615 * blkid_probe_all:
616 * @cache: cache handler
617 *
618 * Probes all block devices.
619 *
620 * Returns: 0 on success, or number less than zero in case of error.
621 */
blkid_probe_all(blkid_cache cache)622 int blkid_probe_all(blkid_cache cache)
623 {
624 int ret;
625
626 DBG(PROBE, ul_debug("Begin blkid_probe_all()"));
627 ret = probe_all(cache, 0);
628 if (ret == 0) {
629 cache->bic_time = time(NULL);
630 cache->bic_flags |= BLKID_BIC_FL_PROBED;
631 }
632 DBG(PROBE, ul_debug("End blkid_probe_all() [rc=%d]", ret));
633 return ret;
634 }
635
636 /**
637 * blkid_probe_all_new:
638 * @cache: cache handler
639 *
640 * Probes all new block devices.
641 *
642 * Returns: 0 on success, or number less than zero in case of error.
643 */
blkid_probe_all_new(blkid_cache cache)644 int blkid_probe_all_new(blkid_cache cache)
645 {
646 int ret;
647
648 DBG(PROBE, ul_debug("Begin blkid_probe_all_new()"));
649 ret = probe_all(cache, 1);
650 DBG(PROBE, ul_debug("End blkid_probe_all_new() [rc=%d]", ret));
651 return ret;
652 }
653
654 /**
655 * blkid_probe_all_removable:
656 * @cache: cache handler
657 *
658 * The libblkid probing is based on devices from /proc/partitions by default.
659 * This file usually does not contain removable devices (e.g. CDROMs) and this kind
660 * of devices are invisible for libblkid.
661 *
662 * This function adds removable block devices to @cache (probing is based on
663 * information from the /sys directory). Don't forget that removable devices
664 * (floppies, CDROMs, ...) could be pretty slow. It's very bad idea to call
665 * this function by default.
666 *
667 * Note that devices which were detected by this function won't be written to
668 * blkid.tab cache file.
669 *
670 * Returns: 0 on success, or number less than zero in case of error.
671 */
blkid_probe_all_removable(blkid_cache cache)672 int blkid_probe_all_removable(blkid_cache cache)
673 {
674 int ret;
675
676 DBG(PROBE, ul_debug("Begin blkid_probe_all_removable()"));
677 ret = probe_all_removable(cache);
678 DBG(PROBE, ul_debug("End blkid_probe_all_removable() [rc=%d]", ret));
679 return ret;
680 }
681
682 #ifdef TEST_PROGRAM
main(int argc,char ** argv)683 int main(int argc, char **argv)
684 {
685 blkid_cache cache = NULL;
686 int ret;
687
688 blkid_init_debug(BLKID_DEBUG_ALL);
689 if (argc != 1) {
690 fprintf(stderr, "Usage: %s\n"
691 "Probe all devices and exit\n", argv[0]);
692 exit(1);
693 }
694 if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
695 fprintf(stderr, "%s: error creating cache (%d)\n",
696 argv[0], ret);
697 exit(1);
698 }
699 if (blkid_probe_all(cache) < 0)
700 printf("%s: error probing devices\n", argv[0]);
701
702 if (blkid_probe_all_removable(cache) < 0)
703 printf("%s: error probing removable devices\n", argv[0]);
704
705 blkid_put_cache(cache);
706 return (0);
707 }
708 #endif
709