devname.c revision 1f1ee1948525632736e8135d797db116d2a34c8d 
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;
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	return dev;
84}
85
86#ifdef HAVE_DEVMAPPER
87static int dm_device_is_leaf(const dev_t dev);
88#endif
89
90/*
91 * Probe a single block device to add to the device cache.
92 */
93static void probe_one(blkid_cache cache, const char *ptname,
94		      dev_t devno, int pri, int only_if_new)
95{
96	blkid_dev dev = NULL;
97	struct list_head *p;
98	const char **dir;
99	char *devname = NULL;
100
101	/* See if we already have this device number in the cache. */
102	list_for_each(p, &cache->bic_devs) {
103		blkid_dev tmp = list_entry(p, struct blkid_struct_dev,
104					   bid_devs);
105#ifdef HAVE_DEVMAPPER
106		if (!dm_device_is_leaf(devno))
107			continue;
108#endif
109		if (tmp->bid_devno == devno) {
110			if (only_if_new)
111				return;
112			dev = blkid_verify(cache, tmp);
113			break;
114		}
115	}
116	if (dev && dev->bid_devno == devno)
117		goto set_pri;
118
119	/*
120	 * Take a quick look at /dev/ptname for the device number.  We check
121	 * all of the likely device directories.  If we don't find it, or if
122	 * the stat information doesn't check out, use blkid_devno_to_devname()
123	 * to find it via an exhaustive search for the device major/minor.
124	 */
125	for (dir = blkid_devdirs; *dir; dir++) {
126		struct stat st;
127		char device[256];
128
129		sprintf(device, "%s/%s", *dir, ptname);
130		if ((dev = blkid_get_dev(cache, device, BLKID_DEV_FIND)) &&
131		    dev->bid_devno == devno)
132			goto set_pri;
133
134		if (stat(device, &st) == 0 && S_ISBLK(st.st_mode) &&
135		    st.st_rdev == devno) {
136			devname = blkid_strdup(device);
137			break;
138		}
139	}
140	if (!devname) {
141		devname = blkid_devno_to_devname(devno);
142		if (!devname)
143			return;
144	}
145	dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
146	free(devname);
147
148set_pri:
149	if (!pri && !strncmp(ptname, "md", 2))
150		pri = BLKID_PRI_MD;
151	if (dev)
152		dev->bid_pri = pri;
153	return;
154}
155
156#ifdef HAVE_DEVMAPPER
157static void dm_quiet_log(int level __BLKID_ATTR((unused)),
158			 const char *file __BLKID_ATTR((unused)),
159			 int line __BLKID_ATTR((unused)),
160			 const char *f __BLKID_ATTR((unused)), ...)
161{
162	return;
163}
164
165/*
166 * device-mapper support
167 */
168static int dm_device_has_dep(const dev_t dev, const char *name)
169{
170	struct dm_task *task;
171	struct dm_deps *deps;
172	struct dm_info info;
173	unsigned int i;
174	int ret = 0;
175
176	task = dm_task_create(DM_DEVICE_DEPS);
177	if (!task)
178		goto out;
179
180	if (!dm_task_set_name(task, name))
181		goto out;
182
183	if (!dm_task_run(task))
184		goto out;
185
186	if (!dm_task_get_info(task, &info))
187		goto out;
188
189	if  (!info.exists)
190		goto out;
191
192	deps = dm_task_get_deps(task);
193	if (!deps || deps->count == 0)
194		goto out;
195
196	for (i = 0; i < deps->count; i++) {
197		dev_t dep_dev = deps->device[i];
198
199		if (dev == dep_dev) {
200			ret = 1;
201			goto out;
202		}
203	}
204
205out:
206	if (task)
207		dm_task_destroy(task);
208
209	return ret;
210}
211
212static int dm_device_is_leaf(const dev_t dev)
213{
214	struct dm_task *task;
215	struct dm_names *names;
216	unsigned int next = 0;
217	int n, ret = 1;
218
219	dm_log_init(dm_quiet_log);
220	task = dm_task_create(DM_DEVICE_LIST);
221	if (!task)
222		goto out;
223
224	dm_log_init(0);
225
226	if (!dm_task_run(task))
227		goto out;
228
229	names = dm_task_get_names(task);
230	if (!names || !names->dev)
231		goto out;
232
233	n = 0;
234	do {
235		names = (struct dm_names *) ((char *)names + next);
236
237		if (dm_device_has_dep(dev, names->name))
238			ret = 0;
239
240		next = names->next;
241	} while (next);
242
243out:
244	if (task)
245		dm_task_destroy(task);
246
247	return ret;
248}
249
250static dev_t dm_get_devno(const char *name)
251{
252	struct dm_task *task;
253	struct dm_info info;
254	dev_t ret = 0;
255
256	task = dm_task_create(DM_DEVICE_INFO);
257	if (!task)
258		goto out;
259
260	if (!dm_task_set_name(task, name))
261		goto out;
262
263	if (!dm_task_run(task))
264		goto out;
265
266	if (!dm_task_get_info(task, &info))
267		goto out;
268
269	if (!info.exists)
270		goto out;
271
272	ret = makedev(info.major, info.minor);
273
274out:
275	if (task)
276		dm_task_destroy(task);
277
278	return ret;
279}
280
281static void dm_probe_all(blkid_cache cache, int only_if_new)
282{
283	struct dm_task *task;
284	struct dm_names *names;
285	unsigned int next = 0;
286	int n;
287
288	dm_log_init(dm_quiet_log);
289	task = dm_task_create(DM_DEVICE_LIST);
290	if (!task)
291		goto out;
292	dm_log_init(0);
293
294	if (!dm_task_run(task))
295		goto out;
296
297	names = dm_task_get_names(task);
298	if (!names || !names->dev)
299		goto out;
300
301	n = 0;
302	do {
303		int rc;
304		char *device = NULL;
305		dev_t dev = 0;
306
307		names = (struct dm_names *) ((char *)names + next);
308
309		rc = asprintf(&device, "mapper/%s", names->name);
310		if (rc < 0)
311			goto try_next;
312
313		dev = dm_get_devno(names->name);
314		if (dev == 0)
315			goto try_next;
316
317		if (!dm_device_is_leaf(dev))
318			goto try_next;
319
320		probe_one(cache, device, dev, BLKID_PRI_DM, only_if_new);
321
322try_next:
323		free(device);
324		next = names->next;
325	} while (next);
326
327out:
328	if (task)
329		dm_task_destroy(task);
330}
331#endif /* HAVE_DEVMAPPER */
332
333#define PROC_PARTITIONS "/proc/partitions"
334#define VG_DIR		"/proc/lvm/VGs"
335
336/*
337 * This function initializes the UUID cache with devices from the LVM
338 * proc hierarchy.  We currently depend on the names of the LVM
339 * hierarchy giving us the device structure in /dev.  (XXX is this a
340 * safe thing to do?)
341 */
342#ifdef VG_DIR
343#include <dirent.h>
344static dev_t lvm_get_devno(const char *lvm_device)
345{
346	FILE *lvf;
347	char buf[1024];
348	int ma, mi;
349	dev_t ret = 0;
350
351	DBG(DEBUG_DEVNAME, printf("opening %s\n", lvm_device));
352	if ((lvf = fopen(lvm_device, "r")) == NULL) {
353		DBG(DEBUG_DEVNAME, printf("%s: (%d) %s\n", lvm_device, errno,
354					  strerror(errno)));
355		return 0;
356	}
357
358	while (fgets(buf, sizeof(buf), lvf)) {
359		if (sscanf(buf, "device: %d:%d", &ma, &mi) == 2) {
360			ret = makedev(ma, mi);
361			break;
362		}
363	}
364	fclose(lvf);
365
366	return ret;
367}
368
369static void lvm_probe_all(blkid_cache cache, int only_if_new)
370{
371	DIR		*vg_list;
372	struct dirent	*vg_iter;
373	int		vg_len = strlen(VG_DIR);
374	dev_t		dev;
375
376	if ((vg_list = opendir(VG_DIR)) == NULL)
377		return;
378
379	DBG(DEBUG_DEVNAME, printf("probing LVM devices under %s\n", VG_DIR));
380
381	while ((vg_iter = readdir(vg_list)) != NULL) {
382		DIR		*lv_list;
383		char		*vdirname;
384		char		*vg_name;
385		struct dirent	*lv_iter;
386
387		vg_name = vg_iter->d_name;
388		if (!strcmp(vg_name, ".") || !strcmp(vg_name, ".."))
389			continue;
390		vdirname = malloc(vg_len + strlen(vg_name) + 8);
391		if (!vdirname)
392			goto exit;
393		sprintf(vdirname, "%s/%s/LVs", VG_DIR, vg_name);
394
395		lv_list = opendir(vdirname);
396		free(vdirname);
397		if (lv_list == NULL)
398			continue;
399
400		while ((lv_iter = readdir(lv_list)) != NULL) {
401			char		*lv_name, *lvm_device;
402
403			lv_name = lv_iter->d_name;
404			if (!strcmp(lv_name, ".") || !strcmp(lv_name, ".."))
405				continue;
406
407			lvm_device = malloc(vg_len + strlen(vg_name) +
408					    strlen(lv_name) + 8);
409			if (!lvm_device) {
410				closedir(lv_list);
411				goto exit;
412			}
413			sprintf(lvm_device, "%s/%s/LVs/%s", VG_DIR, vg_name,
414				lv_name);
415			dev = lvm_get_devno(lvm_device);
416			sprintf(lvm_device, "%s/%s", vg_name, lv_name);
417			DBG(DEBUG_DEVNAME, printf("LVM dev %s: devno 0x%04X\n",
418						  lvm_device,
419						  (unsigned int) dev));
420			probe_one(cache, lvm_device, dev, BLKID_PRI_LVM,
421				  only_if_new);
422			free(lvm_device);
423		}
424		closedir(lv_list);
425	}
426exit:
427	closedir(vg_list);
428}
429#endif
430
431#define PROC_EVMS_VOLUMES "/proc/evms/volumes"
432
433static int
434evms_probe_all(blkid_cache cache, int only_if_new)
435{
436	char line[100];
437	int ma, mi, sz, num = 0;
438	FILE *procpt;
439	char device[110];
440
441	procpt = fopen(PROC_EVMS_VOLUMES, "r");
442	if (!procpt)
443		return 0;
444	while (fgets(line, sizeof(line), procpt)) {
445		if (sscanf (line, " %d %d %d %*s %*s %[^\n ]",
446			    &ma, &mi, &sz, device) != 4)
447			continue;
448
449		DBG(DEBUG_DEVNAME, printf("Checking partition %s (%d, %d)\n",
450					  device, ma, mi));
451
452		probe_one(cache, device, makedev(ma, mi), BLKID_PRI_EVMS,
453			  only_if_new);
454		num++;
455	}
456	fclose(procpt);
457	return num;
458}
459
460/*
461 * Read the device data for all available block devices in the system.
462 */
463static int probe_all(blkid_cache cache, int only_if_new)
464{
465	FILE *proc;
466	char line[1024];
467	char ptname0[128], ptname1[128], *ptname = 0;
468	char *ptnames[2];
469	dev_t devs[2];
470	int ma, mi;
471	unsigned long long sz;
472	int lens[2] = { 0, 0 };
473	int which = 0, last = 0;
474
475	ptnames[0] = ptname0;
476	ptnames[1] = ptname1;
477
478	if (!cache)
479		return -BLKID_ERR_PARAM;
480
481	if (cache->bic_flags & BLKID_BIC_FL_PROBED &&
482	    time(0) - cache->bic_time < BLKID_PROBE_INTERVAL)
483		return 0;
484
485	blkid_read_cache(cache);
486#ifdef HAVE_DEVMAPPER
487	dm_probe_all(cache, only_if_new);
488#endif
489	evms_probe_all(cache, only_if_new);
490#ifdef VG_DIR
491	lvm_probe_all(cache, only_if_new);
492#endif
493
494	proc = fopen(PROC_PARTITIONS, "r");
495	if (!proc)
496		return -BLKID_ERR_PROC;
497
498	while (fgets(line, sizeof(line), proc)) {
499		last = which;
500		which ^= 1;
501		ptname = ptnames[which];
502
503		if (sscanf(line, " %d %d %llu %128[^\n ]",
504			   &ma, &mi, &sz, ptname) != 4)
505			continue;
506		devs[which] = makedev(ma, mi);
507
508		DBG(DEBUG_DEVNAME, printf("read partition name %s\n", ptname));
509
510		/* Skip whole disk devs unless they have no partitions.
511		 * If base name of device has changed, also
512		 * check previous dev to see if it didn't have a partn.
513		 * heuristic: partition name ends in a digit, & partition
514		 * names contain whole device name as substring.
515		 *
516		 * Skip extended partitions.
517		 * heuristic: size is 1
518		 *
519		 * FIXME: skip /dev/{ida,cciss,rd} whole-disk devs
520		 */
521
522		lens[which] = strlen(ptname);
523
524		/* ends in a digit, clearly a partition, so check */
525		if (isdigit(ptname[lens[which] - 1])) {
526			DBG(DEBUG_DEVNAME,
527			    printf("partition dev %s, devno 0x%04X\n",
528				   ptname, (unsigned int) devs[which]));
529
530			if (sz > 1)
531				probe_one(cache, ptname, devs[which], 0,
532					  only_if_new);
533			lens[which] = 0;	/* mark as checked */
534		}
535
536		/*
537		 * If last was not checked because it looked like a whole-disk
538		 * dev, and the device's base name has changed,
539		 * check last as well.
540		 */
541		if (lens[last] && strncmp(ptnames[last], ptname, lens[last])) {
542			DBG(DEBUG_DEVNAME,
543			    printf("whole dev %s, devno 0x%04X\n",
544				   ptnames[last], (unsigned int) devs[last]));
545			probe_one(cache, ptnames[last], devs[last], 0,
546				  only_if_new);
547			lens[last] = 0;
548		}
549	}
550
551	/* Handle the last device if it wasn't partitioned */
552	if (lens[which])
553		probe_one(cache, ptname, devs[which], 0, only_if_new);
554
555	fclose(proc);
556	blkid_flush_cache(cache);
557	return 0;
558}
559
560int blkid_probe_all(blkid_cache cache)
561{
562	int ret;
563
564	DBG(DEBUG_PROBE, printf("Begin blkid_probe_all()\n"));
565	ret = probe_all(cache, 0);
566	cache->bic_time = time(0);
567	cache->bic_flags |= BLKID_BIC_FL_PROBED;
568	DBG(DEBUG_PROBE, printf("End blkid_probe_all()\n"));
569	return ret;
570}
571
572int blkid_probe_all_new(blkid_cache cache)
573{
574	int ret;
575
576	DBG(DEBUG_PROBE, printf("Begin blkid_probe_all_new()\n"));
577	ret = probe_all(cache, 1);
578	DBG(DEBUG_PROBE, printf("End blkid_probe_all_new()\n"));
579	return ret;
580}
581
582
583#ifdef TEST_PROGRAM
584int main(int argc, char **argv)
585{
586	blkid_cache cache = NULL;
587	int ret;
588
589	blkid_debug_mask = DEBUG_ALL;
590	if (argc != 1) {
591		fprintf(stderr, "Usage: %s\n"
592			"Probe all devices and exit\n", argv[0]);
593		exit(1);
594	}
595	if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
596		fprintf(stderr, "%s: error creating cache (%d)\n",
597			argv[0], ret);
598		exit(1);
599	}
600	if (blkid_probe_all(cache) < 0)
601		printf("%s: error probing devices\n", argv[0]);
602
603	blkid_put_cache(cache);
604	return (0);
605}
606#endif
607