devname.c revision bb47c2a4aff6ec6b9be7f30cd04cf7c858a84de4 
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#if HAVE_SYS_STAT_H
29#include <sys/stat.h>
30#endif
31#if HAVE_ERRNO_H
32#include <errno.h>
33#endif
34#if HAVE_SYS_MKDEV_H
35#include <sys/mkdev.h>
36#endif
37#include <time.h>
38
39#include "blkidP.h"
40
41#ifdef HAVE_DEVMAPPER
42#include <libdevmapper.h>
43#endif
44
45/*
46 * Find a dev struct in the cache by device name, if available.
47 *
48 * If there is no entry with the specified device name, and the create
49 * flag is set, then create an empty device entry.
50 */
51blkid_dev blkid_get_dev(blkid_cache cache, const char *devname, int flags)
52{
53	blkid_dev dev = NULL, tmp;
54	struct list_head *p, *pnext;
55
56	if (!cache || !devname)
57		return NULL;
58
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))
62			continue;
63
64		DBG(DEBUG_DEVNAME,
65		    printf("found devname %s in cache\n", tmp->bid_name));
66		dev = tmp;
67		break;
68	}
69
70	if (!dev && (flags & BLKID_DEV_CREATE)) {
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			if (!p)
95				break;
96			dev2 = list_entry(p, struct blkid_struct_dev, bid_devs);
97			if (dev2->bid_flags & BLKID_BID_FL_VERIFIED)
98				continue;
99			if (!dev->bid_type || !dev2->bid_type ||
100			    strcmp(dev->bid_type, dev2->bid_type))
101				continue;
102			if (dev->bid_label && dev2->bid_label &&
103			    strcmp(dev->bid_label, dev2->bid_label))
104				continue;
105			if (dev->bid_uuid && dev2->bid_uuid &&
106			    strcmp(dev->bid_uuid, dev2->bid_uuid))
107				continue;
108			if ((dev->bid_label && !dev2->bid_label) ||
109			    (!dev->bid_label && dev2->bid_label) ||
110			    (dev->bid_uuid && !dev2->bid_uuid) ||
111			    (!dev->bid_uuid && dev2->bid_uuid))
112				continue;
113			dev2 = blkid_verify(cache, dev2);
114			if (dev2 && !(dev2->bid_flags & BLKID_BID_FL_VERIFIED))
115				blkid_free_dev(dev2);
116		}
117	}
118	return dev;
119}
120
121#ifdef HAVE_DEVMAPPER
122static int dm_device_is_leaf(const dev_t dev);
123#endif
124
125/*
126 * Probe a single block device to add to the device cache.
127 */
128static void probe_one(blkid_cache cache, const char *ptname,
129		      dev_t devno, int pri, int only_if_new)
130{
131	blkid_dev dev = NULL;
132	struct list_head *p;
133	const char **dir;
134	char *devname = NULL;
135
136	/* See if we already have this device number in the cache. */
137	list_for_each(p, &cache->bic_devs) {
138		blkid_dev tmp = list_entry(p, struct blkid_struct_dev,
139					   bid_devs);
140#ifdef HAVE_DEVMAPPER
141		if (!dm_device_is_leaf(devno))
142			continue;
143#endif
144		if (tmp->bid_devno == devno) {
145			if (only_if_new)
146				return;
147			dev = blkid_verify(cache, tmp);
148			break;
149		}
150	}
151	if (dev && dev->bid_devno == devno)
152		goto set_pri;
153
154	/*
155	 * Take a quick look at /dev/ptname for the device number.  We check
156	 * all of the likely device directories.  If we don't find it, or if
157	 * the stat information doesn't check out, use blkid_devno_to_devname()
158	 * to find it via an exhaustive search for the device major/minor.
159	 */
160	for (dir = blkid_devdirs; *dir; dir++) {
161		struct stat st;
162		char device[256];
163
164		sprintf(device, "%s/%s", *dir, ptname);
165		if ((dev = blkid_get_dev(cache, device, BLKID_DEV_FIND)) &&
166		    dev->bid_devno == devno)
167			goto set_pri;
168
169		if (stat(device, &st) == 0 && S_ISBLK(st.st_mode) &&
170		    st.st_rdev == devno) {
171			devname = blkid_strdup(device);
172			break;
173		}
174	}
175	if (!devname) {
176		devname = blkid_devno_to_devname(devno);
177		if (!devname)
178			return;
179	}
180	dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
181	free(devname);
182
183set_pri:
184	if (!pri && !strncmp(ptname, "md", 2))
185		pri = BLKID_PRI_MD;
186	if (dev)
187		dev->bid_pri = pri;
188	return;
189}
190
191#ifdef HAVE_DEVMAPPER
192static void dm_quiet_log(int level __BLKID_ATTR((unused)),
193			 const char *file __BLKID_ATTR((unused)),
194			 int line __BLKID_ATTR((unused)),
195			 const char *f __BLKID_ATTR((unused)), ...)
196{
197	return;
198}
199
200/*
201 * device-mapper support
202 */
203static int dm_device_has_dep(const dev_t dev, const char *name)
204{
205	struct dm_task *task;
206	struct dm_deps *deps;
207	struct dm_info info;
208	unsigned int i;
209	int ret = 0;
210
211	task = dm_task_create(DM_DEVICE_DEPS);
212	if (!task)
213		goto out;
214
215	if (!dm_task_set_name(task, name))
216		goto out;
217
218	if (!dm_task_run(task))
219		goto out;
220
221	if (!dm_task_get_info(task, &info))
222		goto out;
223
224	if  (!info.exists)
225		goto out;
226
227	deps = dm_task_get_deps(task);
228	if (!deps || deps->count == 0)
229		goto out;
230
231	for (i = 0; i < deps->count; i++) {
232		dev_t dep_dev = deps->device[i];
233
234		if (dev == dep_dev) {
235			ret = 1;
236			goto out;
237		}
238	}
239
240out:
241	if (task)
242		dm_task_destroy(task);
243
244	return ret;
245}
246
247static int dm_device_is_leaf(const dev_t dev)
248{
249	struct dm_task *task;
250	struct dm_names *names;
251	unsigned int next = 0;
252	int n, ret = 1;
253
254	dm_log_init(dm_quiet_log);
255	task = dm_task_create(DM_DEVICE_LIST);
256	if (!task)
257		goto out;
258
259	dm_log_init(0);
260
261	if (!dm_task_run(task))
262		goto out;
263
264	names = dm_task_get_names(task);
265	if (!names || !names->dev)
266		goto out;
267
268	n = 0;
269	do {
270		names = (struct dm_names *) ((char *)names + next);
271
272		if (dm_device_has_dep(dev, names->name))
273			ret = 0;
274
275		next = names->next;
276	} while (next);
277
278out:
279	if (task)
280		dm_task_destroy(task);
281
282	return ret;
283}
284
285static dev_t dm_get_devno(const char *name)
286{
287	struct dm_task *task;
288	struct dm_info info;
289	dev_t ret = 0;
290
291	task = dm_task_create(DM_DEVICE_INFO);
292	if (!task)
293		goto out;
294
295	if (!dm_task_set_name(task, name))
296		goto out;
297
298	if (!dm_task_run(task))
299		goto out;
300
301	if (!dm_task_get_info(task, &info))
302		goto out;
303
304	if (!info.exists)
305		goto out;
306
307	ret = makedev(info.major, info.minor);
308
309out:
310	if (task)
311		dm_task_destroy(task);
312
313	return ret;
314}
315
316static void dm_probe_all(blkid_cache cache, int only_if_new)
317{
318	struct dm_task *task;
319	struct dm_names *names;
320	unsigned int next = 0;
321	int n;
322
323	dm_log_init(dm_quiet_log);
324	task = dm_task_create(DM_DEVICE_LIST);
325	if (!task)
326		goto out;
327	dm_log_init(0);
328
329	if (!dm_task_run(task))
330		goto out;
331
332	names = dm_task_get_names(task);
333	if (!names || !names->dev)
334		goto out;
335
336	n = 0;
337	do {
338		int rc;
339		char *device = NULL;
340		dev_t dev = 0;
341
342		names = (struct dm_names *) ((char *)names + next);
343
344		rc = asprintf(&device, "mapper/%s", names->name);
345		if (rc < 0)
346			goto try_next;
347
348		dev = dm_get_devno(names->name);
349		if (dev == 0)
350			goto try_next;
351
352		if (!dm_device_is_leaf(dev))
353			goto try_next;
354
355		probe_one(cache, device, dev, BLKID_PRI_DM, only_if_new);
356
357try_next:
358		free(device);
359		next = names->next;
360	} while (next);
361
362out:
363	if (task)
364		dm_task_destroy(task);
365}
366#endif /* HAVE_DEVMAPPER */
367
368#define PROC_PARTITIONS "/proc/partitions"
369#define VG_DIR		"/proc/lvm/VGs"
370
371/*
372 * This function initializes the UUID cache with devices from the LVM
373 * proc hierarchy.  We currently depend on the names of the LVM
374 * hierarchy giving us the device structure in /dev.  (XXX is this a
375 * safe thing to do?)
376 */
377#ifdef VG_DIR
378#include <dirent.h>
379static dev_t lvm_get_devno(const char *lvm_device)
380{
381	FILE *lvf;
382	char buf[1024];
383	int ma, mi;
384	dev_t ret = 0;
385
386	DBG(DEBUG_DEVNAME, printf("opening %s\n", lvm_device));
387	if ((lvf = fopen(lvm_device, "r")) == NULL) {
388		DBG(DEBUG_DEVNAME, printf("%s: (%d) %s\n", lvm_device, errno,
389					  strerror(errno)));
390		return 0;
391	}
392
393	while (fgets(buf, sizeof(buf), lvf)) {
394		if (sscanf(buf, "device: %d:%d", &ma, &mi) == 2) {
395			ret = makedev(ma, mi);
396			break;
397		}
398	}
399	fclose(lvf);
400
401	return ret;
402}
403
404static void lvm_probe_all(blkid_cache cache, int only_if_new)
405{
406	DIR		*vg_list;
407	struct dirent	*vg_iter;
408	int		vg_len = strlen(VG_DIR);
409	dev_t		dev;
410
411	if ((vg_list = opendir(VG_DIR)) == NULL)
412		return;
413
414	DBG(DEBUG_DEVNAME, printf("probing LVM devices under %s\n", VG_DIR));
415
416	while ((vg_iter = readdir(vg_list)) != NULL) {
417		DIR		*lv_list;
418		char		*vdirname;
419		char		*vg_name;
420		struct dirent	*lv_iter;
421
422		vg_name = vg_iter->d_name;
423		if (!strcmp(vg_name, ".") || !strcmp(vg_name, ".."))
424			continue;
425		vdirname = malloc(vg_len + strlen(vg_name) + 8);
426		if (!vdirname)
427			goto exit;
428		sprintf(vdirname, "%s/%s/LVs", VG_DIR, vg_name);
429
430		lv_list = opendir(vdirname);
431		free(vdirname);
432		if (lv_list == NULL)
433			continue;
434
435		while ((lv_iter = readdir(lv_list)) != NULL) {
436			char		*lv_name, *lvm_device;
437
438			lv_name = lv_iter->d_name;
439			if (!strcmp(lv_name, ".") || !strcmp(lv_name, ".."))
440				continue;
441
442			lvm_device = malloc(vg_len + strlen(vg_name) +
443					    strlen(lv_name) + 8);
444			if (!lvm_device) {
445				closedir(lv_list);
446				goto exit;
447			}
448			sprintf(lvm_device, "%s/%s/LVs/%s", VG_DIR, vg_name,
449				lv_name);
450			dev = lvm_get_devno(lvm_device);
451			sprintf(lvm_device, "%s/%s", vg_name, lv_name);
452			DBG(DEBUG_DEVNAME, printf("LVM dev %s: devno 0x%04X\n",
453						  lvm_device,
454						  (unsigned int) dev));
455			probe_one(cache, lvm_device, dev, BLKID_PRI_LVM,
456				  only_if_new);
457			free(lvm_device);
458		}
459		closedir(lv_list);
460	}
461exit:
462	closedir(vg_list);
463}
464#endif
465
466#define PROC_EVMS_VOLUMES "/proc/evms/volumes"
467
468static int
469evms_probe_all(blkid_cache cache, int only_if_new)
470{
471	char line[100];
472	int ma, mi, sz, num = 0;
473	FILE *procpt;
474	char device[110];
475
476	procpt = fopen(PROC_EVMS_VOLUMES, "r");
477	if (!procpt)
478		return 0;
479	while (fgets(line, sizeof(line), procpt)) {
480		if (sscanf (line, " %d %d %d %*s %*s %[^\n ]",
481			    &ma, &mi, &sz, device) != 4)
482			continue;
483
484		DBG(DEBUG_DEVNAME, printf("Checking partition %s (%d, %d)\n",
485					  device, ma, mi));
486
487		probe_one(cache, device, makedev(ma, mi), BLKID_PRI_EVMS,
488			  only_if_new);
489		num++;
490	}
491	fclose(procpt);
492	return num;
493}
494
495/*
496 * Read the device data for all available block devices in the system.
497 */
498static int probe_all(blkid_cache cache, int only_if_new)
499{
500	FILE *proc;
501	char line[1024];
502	char ptname0[128], ptname1[128], *ptname = 0;
503	char *ptnames[2];
504	dev_t devs[2];
505	int ma, mi;
506	unsigned long long sz;
507	int lens[2] = { 0, 0 };
508	int which = 0, last = 0;
509
510	ptnames[0] = ptname0;
511	ptnames[1] = ptname1;
512
513	if (!cache)
514		return -BLKID_ERR_PARAM;
515
516	if (cache->bic_flags & BLKID_BIC_FL_PROBED &&
517	    time(0) - cache->bic_time < BLKID_PROBE_INTERVAL)
518		return 0;
519
520	blkid_read_cache(cache);
521#ifdef HAVE_DEVMAPPER
522	dm_probe_all(cache, only_if_new);
523#endif
524	evms_probe_all(cache, only_if_new);
525#ifdef VG_DIR
526	lvm_probe_all(cache, only_if_new);
527#endif
528
529	proc = fopen(PROC_PARTITIONS, "r");
530	if (!proc)
531		return -BLKID_ERR_PROC;
532
533	while (fgets(line, sizeof(line), proc)) {
534		last = which;
535		which ^= 1;
536		ptname = ptnames[which];
537
538		if (sscanf(line, " %d %d %llu %128[^\n ]",
539			   &ma, &mi, &sz, ptname) != 4)
540			continue;
541		devs[which] = makedev(ma, mi);
542
543		DBG(DEBUG_DEVNAME, printf("read partition name %s\n", ptname));
544
545		/* Skip whole disk devs unless they have no partitions.
546		 * If base name of device has changed, also
547		 * check previous dev to see if it didn't have a partn.
548		 * heuristic: partition name ends in a digit, & partition
549		 * names contain whole device name as substring.
550		 *
551		 * Skip extended partitions.
552		 * heuristic: size is 1
553		 *
554		 * FIXME: skip /dev/{ida,cciss,rd} whole-disk devs
555		 */
556
557		lens[which] = strlen(ptname);
558
559		/* ends in a digit, clearly a partition, so check */
560		if (isdigit(ptname[lens[which] - 1])) {
561			DBG(DEBUG_DEVNAME,
562			    printf("partition dev %s, devno 0x%04X\n",
563				   ptname, (unsigned int) devs[which]));
564
565			if (sz > 1)
566				probe_one(cache, ptname, devs[which], 0,
567					  only_if_new);
568			lens[which] = 0;	/* mark as checked */
569		}
570
571		/*
572		 * If last was not checked because it looked like a whole-disk
573		 * dev, and the device's base name has changed,
574		 * check last as well.
575		 */
576		if (lens[last] && strncmp(ptnames[last], ptname, lens[last])) {
577			DBG(DEBUG_DEVNAME,
578			    printf("whole dev %s, devno 0x%04X\n",
579				   ptnames[last], (unsigned int) devs[last]));
580			probe_one(cache, ptnames[last], devs[last], 0,
581				  only_if_new);
582			lens[last] = 0;
583		}
584	}
585
586	/* Handle the last device if it wasn't partitioned */
587	if (lens[which])
588		probe_one(cache, ptname, devs[which], 0, only_if_new);
589
590	fclose(proc);
591	blkid_flush_cache(cache);
592	return 0;
593}
594
595int blkid_probe_all(blkid_cache cache)
596{
597	int ret;
598
599	DBG(DEBUG_PROBE, printf("Begin blkid_probe_all()\n"));
600	ret = probe_all(cache, 0);
601	cache->bic_time = time(0);
602	cache->bic_flags |= BLKID_BIC_FL_PROBED;
603	DBG(DEBUG_PROBE, printf("End blkid_probe_all()\n"));
604	return ret;
605}
606
607int blkid_probe_all_new(blkid_cache cache)
608{
609	int ret;
610
611	DBG(DEBUG_PROBE, printf("Begin blkid_probe_all_new()\n"));
612	ret = probe_all(cache, 1);
613	DBG(DEBUG_PROBE, printf("End blkid_probe_all_new()\n"));
614	return ret;
615}
616
617
618#ifdef TEST_PROGRAM
619int main(int argc, char **argv)
620{
621	blkid_cache cache = NULL;
622	int ret;
623
624	blkid_debug_mask = DEBUG_ALL;
625	if (argc != 1) {
626		fprintf(stderr, "Usage: %s\n"
627			"Probe all devices and exit\n", argv[0]);
628		exit(1);
629	}
630	if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
631		fprintf(stderr, "%s: error creating cache (%d)\n",
632			argv[0], ret);
633		exit(1);
634	}
635	if (blkid_probe_all(cache) < 0)
636		printf("%s: error probing devices\n", argv[0]);
637
638	blkid_put_cache(cache);
639	return (0);
640}
641#endif
642