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 */
blkid_get_dev(blkid_cache cache,const char * devname,int flags)48 blkid_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 */
121 static const char *dirlist[] = { "/dev", "/devfs", "/devices", NULL };
122
is_dm_leaf(const char * devname)123 static 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 * Since 2.6.29 (patch 784aae735d9b0bba3f8b9faef4c8b30df3bf0128) kernel sysfs
157 * provides the real DM device names in /sys/block/<ptname>/dm/name
158 */
get_dm_name(const char * ptname)159 static char *get_dm_name(const char *ptname)
160 {
161 FILE *f;
162 size_t sz;
163 char path[256], name[256], *res = NULL;
164
165 snprintf(path, sizeof(path), "/sys/block/%s/dm/name", ptname);
166 if ((f = fopen(path, "r")) == NULL)
167 return NULL;
168
169 /* read "<name>\n" from sysfs */
170 if (fgets(name, sizeof(name), f) && (sz = strlen(name)) > 1) {
171 name[sz - 1] = '\0';
172 snprintf(path, sizeof(path), "/dev/mapper/%s", name);
173 res = blkid_strdup(path);
174 }
175 fclose(f);
176 return res;
177 }
178
179 /*
180 * Probe a single block device to add to the device cache.
181 */
probe_one(blkid_cache cache,const char * ptname,dev_t devno,int pri,int only_if_new)182 static void probe_one(blkid_cache cache, const char *ptname,
183 dev_t devno, int pri, int only_if_new)
184 {
185 blkid_dev dev = NULL;
186 struct list_head *p, *pnext;
187 const char **dir;
188 char *devname = NULL;
189
190 /* See if we already have this device number in the cache. */
191 list_for_each_safe(p, pnext, &cache->bic_devs) {
192 blkid_dev tmp = list_entry(p, struct blkid_struct_dev,
193 bid_devs);
194 if (tmp->bid_devno == devno) {
195 if (only_if_new && !access(tmp->bid_name, F_OK))
196 return;
197 dev = blkid_verify(cache, tmp);
198 if (dev && (dev->bid_flags & BLKID_BID_FL_VERIFIED))
199 break;
200 dev = 0;
201 }
202 }
203 if (dev && dev->bid_devno == devno)
204 goto set_pri;
205
206 /* Try to translate private device-mapper dm-<N> names
207 * to standard /dev/mapper/<name>.
208 */
209 if (!strncmp(ptname, "dm-", 3) && isdigit(ptname[3])) {
210 devname = get_dm_name(ptname);
211 if (!devname)
212 blkid__scan_dir("/dev/mapper", devno, 0, &devname);
213 if (devname)
214 goto get_dev;
215 }
216
217 /*
218 * Take a quick look at /dev/ptname for the device number. We check
219 * all of the likely device directories. If we don't find it, or if
220 * the stat information doesn't check out, use blkid_devno_to_devname()
221 * to find it via an exhaustive search for the device major/minor.
222 */
223 for (dir = dirlist; *dir; dir++) {
224 struct stat st;
225 char device[256];
226
227 sprintf(device, "%s/%s", *dir, ptname);
228 if ((dev = blkid_get_dev(cache, device, BLKID_DEV_FIND)) &&
229 dev->bid_devno == devno)
230 goto set_pri;
231
232 if (stat(device, &st) == 0 && S_ISBLK(st.st_mode) &&
233 st.st_rdev == devno) {
234 devname = blkid_strdup(device);
235 goto get_dev;
236 }
237 }
238 /* Do a short-cut scan of /dev/mapper first */
239 if (!devname)
240 devname = get_dm_name(ptname);
241 if (!devname)
242 blkid__scan_dir("/dev/mapper", devno, 0, &devname);
243 if (!devname) {
244 devname = blkid_devno_to_devname(devno);
245 if (!devname)
246 return;
247 }
248 get_dev:
249 dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
250 free(devname);
251 set_pri:
252 if (dev) {
253 if (pri)
254 dev->bid_pri = pri;
255 else if (!strncmp(dev->bid_name, "/dev/mapper/", 11)) {
256 dev->bid_pri = BLKID_PRI_DM;
257 if (is_dm_leaf(ptname))
258 dev->bid_pri += 5;
259 } else if (!strncmp(ptname, "md", 2))
260 dev->bid_pri = BLKID_PRI_MD;
261 }
262 return;
263 }
264
265 #define PROC_PARTITIONS "/proc/partitions"
266 #define VG_DIR "/proc/lvm/VGs"
267
268 /*
269 * This function initializes the UUID cache with devices from the LVM
270 * proc hierarchy. We currently depend on the names of the LVM
271 * hierarchy giving us the device structure in /dev. (XXX is this a
272 * safe thing to do?)
273 */
274 #ifdef VG_DIR
lvm_get_devno(const char * lvm_device)275 static dev_t lvm_get_devno(const char *lvm_device)
276 {
277 FILE *lvf;
278 char buf[1024];
279 int ma, mi;
280 dev_t ret = 0;
281
282 DBG(DEBUG_DEVNAME, printf("opening %s\n", lvm_device));
283 if ((lvf = fopen(lvm_device, "r")) == NULL) {
284 DBG(DEBUG_DEVNAME, printf("%s: (%d) %s\n", lvm_device, errno,
285 strerror(errno)));
286 return 0;
287 }
288
289 while (fgets(buf, sizeof(buf), lvf)) {
290 if (sscanf(buf, "device: %d:%d", &ma, &mi) == 2) {
291 ret = makedev(ma, mi);
292 break;
293 }
294 }
295 fclose(lvf);
296
297 return ret;
298 }
299
lvm_probe_all(blkid_cache cache,int only_if_new)300 static void lvm_probe_all(blkid_cache cache, int only_if_new)
301 {
302 DIR *vg_list;
303 struct dirent *vg_iter;
304 int vg_len = strlen(VG_DIR);
305 dev_t dev;
306
307 if ((vg_list = opendir(VG_DIR)) == NULL)
308 return;
309
310 DBG(DEBUG_DEVNAME, printf("probing LVM devices under %s\n", VG_DIR));
311
312 while ((vg_iter = readdir(vg_list)) != NULL) {
313 DIR *lv_list;
314 char *vdirname;
315 char *vg_name;
316 struct dirent *lv_iter;
317
318 vg_name = vg_iter->d_name;
319 if (!strcmp(vg_name, ".") || !strcmp(vg_name, ".."))
320 continue;
321 vdirname = malloc(vg_len + strlen(vg_name) + 8);
322 if (!vdirname)
323 goto exit;
324 sprintf(vdirname, "%s/%s/LVs", VG_DIR, vg_name);
325
326 lv_list = opendir(vdirname);
327 free(vdirname);
328 if (lv_list == NULL)
329 continue;
330
331 while ((lv_iter = readdir(lv_list)) != NULL) {
332 char *lv_name, *lvm_device;
333
334 lv_name = lv_iter->d_name;
335 if (!strcmp(lv_name, ".") || !strcmp(lv_name, ".."))
336 continue;
337
338 lvm_device = malloc(vg_len + strlen(vg_name) +
339 strlen(lv_name) + 8);
340 if (!lvm_device) {
341 closedir(lv_list);
342 goto exit;
343 }
344 sprintf(lvm_device, "%s/%s/LVs/%s", VG_DIR, vg_name,
345 lv_name);
346 dev = lvm_get_devno(lvm_device);
347 sprintf(lvm_device, "%s/%s", vg_name, lv_name);
348 DBG(DEBUG_DEVNAME, printf("LVM dev %s: devno 0x%04X\n",
349 lvm_device,
350 (unsigned int) dev));
351 probe_one(cache, lvm_device, dev, BLKID_PRI_LVM,
352 only_if_new);
353 free(lvm_device);
354 }
355 closedir(lv_list);
356 }
357 exit:
358 closedir(vg_list);
359 }
360 #endif
361
362 #define PROC_EVMS_VOLUMES "/proc/evms/volumes"
363
364 static int
evms_probe_all(blkid_cache cache,int only_if_new)365 evms_probe_all(blkid_cache cache, int only_if_new)
366 {
367 char line[100];
368 int ma, mi, sz, num = 0;
369 FILE *procpt;
370 char device[110];
371
372 procpt = fopen(PROC_EVMS_VOLUMES, "r");
373 if (!procpt)
374 return 0;
375 while (fgets(line, sizeof(line), procpt)) {
376 if (sscanf (line, " %d %d %d %*s %*s %[^\n ]",
377 &ma, &mi, &sz, device) != 4)
378 continue;
379
380 DBG(DEBUG_DEVNAME, printf("Checking partition %s (%d, %d)\n",
381 device, ma, mi));
382
383 probe_one(cache, device, makedev(ma, mi), BLKID_PRI_EVMS,
384 only_if_new);
385 num++;
386 }
387 fclose(procpt);
388 return num;
389 }
390
391 /*
392 * Read the device data for all available block devices in the system.
393 */
probe_all(blkid_cache cache,int only_if_new)394 static int probe_all(blkid_cache cache, int only_if_new)
395 {
396 FILE *proc;
397 char line[1024];
398 char ptname0[128], ptname1[128], *ptname = 0;
399 char *ptnames[2];
400 dev_t devs[2];
401 int ma, mi;
402 unsigned long long sz;
403 int lens[2] = { 0, 0 };
404 int which = 0, last = 0;
405 struct list_head *p, *pnext;
406
407 ptnames[0] = ptname0;
408 ptnames[1] = ptname1;
409
410 if (!cache)
411 return -BLKID_ERR_PARAM;
412
413 if (cache->bic_flags & BLKID_BIC_FL_PROBED &&
414 time(0) - cache->bic_time < BLKID_PROBE_INTERVAL)
415 return 0;
416
417 blkid_read_cache(cache);
418 evms_probe_all(cache, only_if_new);
419 #ifdef VG_DIR
420 lvm_probe_all(cache, only_if_new);
421 #endif
422
423 proc = fopen(PROC_PARTITIONS, "r");
424 if (!proc)
425 return -BLKID_ERR_PROC;
426
427 while (fgets(line, sizeof(line), proc)) {
428 last = which;
429 which ^= 1;
430 ptname = ptnames[which];
431
432 if (sscanf(line, " %d %d %llu %128[^\n ]",
433 &ma, &mi, &sz, ptname) != 4)
434 continue;
435 devs[which] = makedev(ma, mi);
436
437 DBG(DEBUG_DEVNAME, printf("read partition name %s\n", ptname));
438
439 /* Skip whole disk devs unless they have no partitions.
440 * If base name of device has changed, also
441 * check previous dev to see if it didn't have a partn.
442 * heuristic: partition name ends in a digit, & partition
443 * names contain whole device name as substring.
444 *
445 * Skip extended partitions.
446 * heuristic: size is 1
447 *
448 * FIXME: skip /dev/{ida,cciss,rd} whole-disk devs
449 */
450
451 lens[which] = strlen(ptname);
452
453 /* ends in a digit, clearly a partition, so check */
454 if (isdigit(ptname[lens[which] - 1])) {
455 DBG(DEBUG_DEVNAME,
456 printf("partition dev %s, devno 0x%04X\n",
457 ptname, (unsigned int) devs[which]));
458
459 if (sz > 1)
460 probe_one(cache, ptname, devs[which], 0,
461 only_if_new);
462 lens[which] = 0; /* mark as checked */
463 }
464
465 /*
466 * If last was a whole disk and we just found a partition
467 * on it, remove the whole-disk dev from the cache if
468 * it exists.
469 */
470 if (lens[last] && !strncmp(ptnames[last], ptname, lens[last])) {
471 list_for_each_safe(p, pnext, &cache->bic_devs) {
472 blkid_dev tmp;
473
474 /* find blkid dev for the whole-disk devno */
475 tmp = list_entry(p, struct blkid_struct_dev,
476 bid_devs);
477 if (tmp->bid_devno == devs[last]) {
478 DBG(DEBUG_DEVNAME,
479 printf("freeing %s\n",
480 tmp->bid_name));
481 blkid_free_dev(tmp);
482 cache->bic_flags |= BLKID_BIC_FL_CHANGED;
483 break;
484 }
485 }
486 lens[last] = 0;
487 }
488 /*
489 * If last was not checked because it looked like a whole-disk
490 * dev, and the device's base name has changed,
491 * check last as well.
492 */
493 if (lens[last] && strncmp(ptnames[last], ptname, lens[last])) {
494 DBG(DEBUG_DEVNAME,
495 printf("whole dev %s, devno 0x%04X\n",
496 ptnames[last], (unsigned int) devs[last]));
497 probe_one(cache, ptnames[last], devs[last], 0,
498 only_if_new);
499 lens[last] = 0;
500 }
501 }
502
503 /* Handle the last device if it wasn't partitioned */
504 if (lens[which])
505 probe_one(cache, ptname, devs[which], 0, only_if_new);
506
507 fclose(proc);
508 blkid_flush_cache(cache);
509 return 0;
510 }
511
blkid_probe_all(blkid_cache cache)512 int blkid_probe_all(blkid_cache cache)
513 {
514 int ret;
515
516 DBG(DEBUG_PROBE, printf("Begin blkid_probe_all()\n"));
517 ret = probe_all(cache, 0);
518 cache->bic_time = time(0);
519 cache->bic_flags |= BLKID_BIC_FL_PROBED;
520 DBG(DEBUG_PROBE, printf("End blkid_probe_all()\n"));
521 return ret;
522 }
523
blkid_probe_all_new(blkid_cache cache)524 int blkid_probe_all_new(blkid_cache cache)
525 {
526 int ret;
527
528 DBG(DEBUG_PROBE, printf("Begin blkid_probe_all_new()\n"));
529 ret = probe_all(cache, 1);
530 DBG(DEBUG_PROBE, printf("End blkid_probe_all_new()\n"));
531 return ret;
532 }
533
534
535 #ifdef TEST_PROGRAM
main(int argc,char ** argv)536 int main(int argc, char **argv)
537 {
538 blkid_cache cache = NULL;
539 int ret;
540
541 blkid_debug_mask = DEBUG_ALL;
542 if (argc != 1) {
543 fprintf(stderr, "Usage: %s\n"
544 "Probe all devices and exit\n", argv[0]);
545 exit(1);
546 }
547 if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
548 fprintf(stderr, "%s: error creating cache (%d)\n",
549 argv[0], ret);
550 exit(1);
551 }
552 if (blkid_probe_all(cache) < 0)
553 printf("%s: error probing devices\n", argv[0]);
554
555 blkid_put_cache(cache);
556 return (0);
557 }
558 #endif
559