devname.c revision a02fa9beb8ea198766a81c0bf01aa04dc8787237 
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, const char *file, int line,
158			 const char *f, ...)
159{
160	return;
161}
162
163/*
164 * device-mapper support
165 */
166static int dm_device_has_dep(const dev_t dev, const char *name)
167{
168	struct dm_task *task;
169	struct dm_deps *deps;
170	struct dm_info info;
171	int i;
172
173	task = dm_task_create(DM_DEVICE_DEPS);
174	if (!task)
175		return 0;
176
177	dm_task_set_name(task, name);
178	dm_task_run(task);
179	dm_task_get_info(task, &info);
180
181	if (!info.exists) {
182		dm_task_destroy(task);
183		return 0;
184	}
185
186	deps = dm_task_get_deps(task);
187	if (!deps || deps->count == 0) {
188		dm_task_destroy(task);
189		return 0;
190	}
191
192	for (i = 0; i < deps->count; i++) {
193		dev_t dep_dev = deps->device[i];
194
195		if (dev == dep_dev) {
196			dm_task_destroy(task);
197			return 1;
198		}
199	}
200
201	dm_task_destroy(task);
202	return 0;
203}
204
205static int dm_device_is_leaf(const dev_t dev)
206{
207	struct dm_task *task;
208	struct dm_names *names;
209	unsigned int next = 0;
210	int n, ret = 1;
211
212	dm_log_init(dm_quiet_log);
213	task = dm_task_create(DM_DEVICE_LIST);
214	if (!task)
215		return 1;
216	dm_log_init(0);
217
218	dm_task_run(task);
219	names = dm_task_get_names(task);
220	if (!names || !names->dev) {
221		dm_task_destroy(task);
222		return 1;
223	}
224
225	n = 0;
226	do {
227		names = (void *)names + next;
228
229		if (dm_device_has_dep(dev, names->name))
230			ret = 0;
231
232		next = names->next;
233	} while (next);
234
235	dm_task_destroy(task);
236
237	return ret;
238}
239
240static dev_t dm_get_devno(const char *name)
241{
242	struct dm_task *task;
243	struct dm_info info;
244	dev_t ret = 0;
245
246	task = dm_task_create(DM_DEVICE_INFO);
247	if (!task)
248		return ret;
249
250	dm_task_set_name(task, name);
251	dm_task_run(task);
252	dm_task_get_info(task, &info);
253
254	if (!info.exists) {
255		dm_task_destroy(task);
256		return ret;
257	}
258
259	ret = makedev(info.major, info.minor);
260
261	dm_task_destroy(task);
262
263	return ret;
264}
265
266static void dm_probe_all(blkid_cache cache, int only_if_new)
267{
268	struct dm_task *task;
269	struct dm_names *names;
270	unsigned int next = 0;
271	int n;
272
273	dm_log_init(dm_quiet_log);
274	task = dm_task_create(DM_DEVICE_LIST);
275	if (!task)
276		return;
277	dm_log_init(0);
278
279	dm_task_run(task);
280	names = dm_task_get_names(task);
281	if (!names || !names->dev) {
282		dm_task_destroy(task);
283		return;
284	}
285
286	n = 0;
287	do {
288		int rc;
289		char *device = NULL;
290		dev_t dev = 0;
291
292		names = (void *)names + next;
293
294		rc = asprintf(&device, "mapper/%s", names->name);
295		if (rc < 0)
296			goto try_next;
297
298		dev = dm_get_devno(names->name);
299		if (dev == 0)
300			goto try_next;
301
302		if (!dm_device_is_leaf(dev))
303			goto try_next;
304
305		probe_one(cache, device, dev, BLKID_PRI_DM, only_if_new);
306
307try_next:
308		next = names->next;
309	} while (next);
310
311	dm_task_destroy(task);
312}
313#endif /* HAVE_DEVMAPPER */
314
315#define PROC_PARTITIONS "/proc/partitions"
316#define VG_DIR		"/proc/lvm/VGs"
317
318/*
319 * This function initializes the UUID cache with devices from the LVM
320 * proc hierarchy.  We currently depend on the names of the LVM
321 * hierarchy giving us the device structure in /dev.  (XXX is this a
322 * safe thing to do?)
323 */
324#ifdef VG_DIR
325#include <dirent.h>
326static dev_t lvm_get_devno(const char *lvm_device)
327{
328	FILE *lvf;
329	char buf[1024];
330	int ma, mi;
331	dev_t ret = 0;
332
333	DBG(DEBUG_DEVNAME, printf("opening %s\n", lvm_device));
334	if ((lvf = fopen(lvm_device, "r")) == NULL) {
335		DBG(DEBUG_DEVNAME, printf("%s: (%d) %s\n", lvm_device, errno,
336					  strerror(errno)));
337		return 0;
338	}
339
340	while (fgets(buf, sizeof(buf), lvf)) {
341		if (sscanf(buf, "device: %d:%d", &ma, &mi) == 2) {
342			ret = makedev(ma, mi);
343			break;
344		}
345	}
346	fclose(lvf);
347
348	return ret;
349}
350
351static void lvm_probe_all(blkid_cache cache, int only_if_new)
352{
353	DIR		*vg_list;
354	struct dirent	*vg_iter;
355	int		vg_len = strlen(VG_DIR);
356	dev_t		dev;
357
358	if ((vg_list = opendir(VG_DIR)) == NULL)
359		return;
360
361	DBG(DEBUG_DEVNAME, printf("probing LVM devices under %s\n", VG_DIR));
362
363	while ((vg_iter = readdir(vg_list)) != NULL) {
364		DIR		*lv_list;
365		char		*vdirname;
366		char		*vg_name;
367		struct dirent	*lv_iter;
368
369		vg_name = vg_iter->d_name;
370		if (!strcmp(vg_name, ".") || !strcmp(vg_name, ".."))
371			continue;
372		vdirname = malloc(vg_len + strlen(vg_name) + 8);
373		if (!vdirname)
374			goto exit;
375		sprintf(vdirname, "%s/%s/LVs", VG_DIR, vg_name);
376
377		lv_list = opendir(vdirname);
378		free(vdirname);
379		if (lv_list == NULL)
380			continue;
381
382		while ((lv_iter = readdir(lv_list)) != NULL) {
383			char		*lv_name, *lvm_device;
384
385			lv_name = lv_iter->d_name;
386			if (!strcmp(lv_name, ".") || !strcmp(lv_name, ".."))
387				continue;
388
389			lvm_device = malloc(vg_len + strlen(vg_name) +
390					    strlen(lv_name) + 8);
391			if (!lvm_device) {
392				closedir(lv_list);
393				goto exit;
394			}
395			sprintf(lvm_device, "%s/%s/LVs/%s", VG_DIR, vg_name,
396				lv_name);
397			dev = lvm_get_devno(lvm_device);
398			sprintf(lvm_device, "%s/%s", vg_name, lv_name);
399			DBG(DEBUG_DEVNAME, printf("LVM dev %s: devno 0x%04X\n",
400						  lvm_device,
401						  (unsigned int) dev));
402			probe_one(cache, lvm_device, dev, BLKID_PRI_LVM,
403				  only_if_new);
404			free(lvm_device);
405		}
406		closedir(lv_list);
407	}
408exit:
409	closedir(vg_list);
410}
411#endif
412
413#define PROC_EVMS_VOLUMES "/proc/evms/volumes"
414
415static int
416evms_probe_all(blkid_cache cache, int only_if_new)
417{
418	char line[100];
419	int ma, mi, sz, num = 0;
420	FILE *procpt;
421	char device[110];
422
423	procpt = fopen(PROC_EVMS_VOLUMES, "r");
424	if (!procpt)
425		return 0;
426	while (fgets(line, sizeof(line), procpt)) {
427		if (sscanf (line, " %d %d %d %*s %*s %[^\n ]",
428			    &ma, &mi, &sz, device) != 4)
429			continue;
430
431		DBG(DEBUG_DEVNAME, printf("Checking partition %s (%d, %d)\n",
432					  device, ma, mi));
433
434		probe_one(cache, device, makedev(ma, mi), BLKID_PRI_EVMS,
435			  only_if_new);
436		num++;
437	}
438	fclose(procpt);
439	return num;
440}
441
442/*
443 * Read the device data for all available block devices in the system.
444 */
445static int probe_all(blkid_cache cache, int only_if_new)
446{
447	FILE *proc;
448	char line[1024];
449	char ptname0[128], ptname1[128], *ptname = 0;
450	char *ptnames[2];
451	dev_t devs[2];
452	int ma, mi;
453	unsigned long long sz;
454	int lens[2] = { 0, 0 };
455	int which = 0, last = 0;
456
457	ptnames[0] = ptname0;
458	ptnames[1] = ptname1;
459
460	if (!cache)
461		return -BLKID_ERR_PARAM;
462
463	if (cache->bic_flags & BLKID_BIC_FL_PROBED &&
464	    time(0) - cache->bic_time < BLKID_PROBE_INTERVAL)
465		return 0;
466
467	blkid_read_cache(cache);
468#ifdef HAVE_DEVMAPPER
469	dm_probe_all(cache, only_if_new);
470#endif
471	evms_probe_all(cache, only_if_new);
472#ifdef VG_DIR
473	lvm_probe_all(cache, only_if_new);
474#endif
475
476	proc = fopen(PROC_PARTITIONS, "r");
477	if (!proc)
478		return -BLKID_ERR_PROC;
479
480	while (fgets(line, sizeof(line), proc)) {
481		last = which;
482		which ^= 1;
483		ptname = ptnames[which];
484
485		if (sscanf(line, " %d %d %llu %128[^\n ]",
486			   &ma, &mi, &sz, ptname) != 4)
487			continue;
488		devs[which] = makedev(ma, mi);
489
490		DBG(DEBUG_DEVNAME, printf("read partition name %s\n", ptname));
491
492		/* Skip whole disk devs unless they have no partitions
493		 * If we don't have a partition on this dev, also
494		 * check previous dev to see if it didn't have a partn.
495		 * heuristic: partition name ends in a digit.
496		 *
497		 * Skip extended partitions.
498		 * heuristic: size is 1
499		 *
500		 * FIXME: skip /dev/{ida,cciss,rd} whole-disk devs
501		 */
502
503		lens[which] = strlen(ptname);
504		if (isdigit(ptname[lens[which] - 1])) {
505			DBG(DEBUG_DEVNAME,
506			    printf("partition dev %s, devno 0x%04X\n",
507				   ptname, (unsigned int) devs[which]));
508
509			if (sz > 1)
510				probe_one(cache, ptname, devs[which], 0,
511					  only_if_new);
512			lens[which] = 0;
513			lens[last] = 0;
514		} else if (lens[last] && strncmp(ptnames[last], ptname,
515						 lens[last])) {
516			DBG(DEBUG_DEVNAME,
517			    printf("whole dev %s, devno 0x%04X\n",
518				   ptnames[last], (unsigned int) devs[last]));
519			probe_one(cache, ptnames[last], devs[last], 0,
520				  only_if_new);
521			lens[last] = 0;
522		}
523	}
524
525	/* Handle the last device if it wasn't partitioned */
526	if (lens[which])
527		probe_one(cache, ptname, devs[which], 0, only_if_new);
528
529	fclose(proc);
530	blkid_flush_cache(cache);
531	return 0;
532}
533
534int blkid_probe_all(blkid_cache cache)
535{
536	int ret;
537
538	DBG(DEBUG_PROBE, printf("Begin blkid_probe_all()\n"));
539	ret = probe_all(cache, 0);
540	cache->bic_time = time(0);
541	cache->bic_flags |= BLKID_BIC_FL_PROBED;
542	DBG(DEBUG_PROBE, printf("End blkid_probe_all()\n"));
543	return ret;
544}
545
546int blkid_probe_all_new(blkid_cache cache)
547{
548	int ret;
549
550	DBG(DEBUG_PROBE, printf("Begin blkid_probe_all_new()\n"));
551	ret = probe_all(cache, 1);
552	DBG(DEBUG_PROBE, printf("End blkid_probe_all_new()\n"));
553	return ret;
554}
555
556
557#ifdef TEST_PROGRAM
558int main(int argc, char **argv)
559{
560	blkid_cache cache = NULL;
561	int ret;
562
563	blkid_debug_mask = DEBUG_ALL;
564	if (argc != 1) {
565		fprintf(stderr, "Usage: %s\n"
566			"Probe all devices and exit\n", argv[0]);
567		exit(1);
568	}
569	if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
570		fprintf(stderr, "%s: error creating cache (%d)\n",
571			argv[0], ret);
572		exit(1);
573	}
574	if (blkid_probe_all(cache) < 0)
575		printf("%s: error probing devices\n", argv[0]);
576
577	blkid_put_cache(cache);
578	return (0);
579}
580#endif
581