devname.c revision d4e0b1c6f5aa8c6a248d9149ed5634a310952411 
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
175	task = dm_task_create(DM_DEVICE_DEPS);
176	if (!task)
177		return 0;
178
179	dm_task_set_name(task, name);
180	dm_task_run(task);
181	dm_task_get_info(task, &info);
182
183	if (!info.exists) {
184		dm_task_destroy(task);
185		return 0;
186	}
187
188	deps = dm_task_get_deps(task);
189	if (!deps || deps->count == 0) {
190		dm_task_destroy(task);
191		return 0;
192	}
193
194	for (i = 0; i < deps->count; i++) {
195		dev_t dep_dev = deps->device[i];
196
197		if (dev == dep_dev) {
198			dm_task_destroy(task);
199			return 1;
200		}
201	}
202
203	dm_task_destroy(task);
204	return 0;
205}
206
207static int dm_device_is_leaf(const dev_t dev)
208{
209	struct dm_task *task;
210	struct dm_names *names;
211	unsigned int next = 0;
212	int n, ret = 1;
213
214	dm_log_init(dm_quiet_log);
215	task = dm_task_create(DM_DEVICE_LIST);
216	if (!task)
217		return 1;
218	dm_log_init(0);
219
220	dm_task_run(task);
221	names = dm_task_get_names(task);
222	if (!names || !names->dev) {
223		dm_task_destroy(task);
224		return 1;
225	}
226
227	n = 0;
228	do {
229		names = (struct dm_names *) ((char *)names + next);
230
231		if (dm_device_has_dep(dev, names->name))
232			ret = 0;
233
234		next = names->next;
235	} while (next);
236
237	dm_task_destroy(task);
238
239	return ret;
240}
241
242static dev_t dm_get_devno(const char *name)
243{
244	struct dm_task *task;
245	struct dm_info info;
246	dev_t ret = 0;
247
248	task = dm_task_create(DM_DEVICE_INFO);
249	if (!task)
250		return ret;
251
252	dm_task_set_name(task, name);
253	dm_task_run(task);
254	dm_task_get_info(task, &info);
255
256	if (!info.exists) {
257		dm_task_destroy(task);
258		return ret;
259	}
260
261	ret = makedev(info.major, info.minor);
262
263	dm_task_destroy(task);
264
265	return ret;
266}
267
268static void dm_probe_all(blkid_cache cache, int only_if_new)
269{
270	struct dm_task *task;
271	struct dm_names *names;
272	unsigned int next = 0;
273	int n;
274
275	dm_log_init(dm_quiet_log);
276	task = dm_task_create(DM_DEVICE_LIST);
277	if (!task)
278		return;
279	dm_log_init(0);
280
281	dm_task_run(task);
282	names = dm_task_get_names(task);
283	if (!names || !names->dev) {
284		dm_task_destroy(task);
285		return;
286	}
287
288	n = 0;
289	do {
290		int rc;
291		char *device = NULL;
292		dev_t dev = 0;
293
294		names = (struct dm_names *) ((char *)names + next);
295
296		rc = asprintf(&device, "mapper/%s", names->name);
297		if (rc < 0)
298			goto try_next;
299
300		dev = dm_get_devno(names->name);
301		if (dev == 0)
302			goto try_next;
303
304		if (!dm_device_is_leaf(dev))
305			goto try_next;
306
307		probe_one(cache, device, dev, BLKID_PRI_DM, only_if_new);
308
309try_next:
310		free(device);
311		next = names->next;
312	} while (next);
313
314	dm_task_destroy(task);
315}
316#endif /* HAVE_DEVMAPPER */
317
318#define PROC_PARTITIONS "/proc/partitions"
319#define VG_DIR		"/proc/lvm/VGs"
320
321/*
322 * This function initializes the UUID cache with devices from the LVM
323 * proc hierarchy.  We currently depend on the names of the LVM
324 * hierarchy giving us the device structure in /dev.  (XXX is this a
325 * safe thing to do?)
326 */
327#ifdef VG_DIR
328#include <dirent.h>
329static dev_t lvm_get_devno(const char *lvm_device)
330{
331	FILE *lvf;
332	char buf[1024];
333	int ma, mi;
334	dev_t ret = 0;
335
336	DBG(DEBUG_DEVNAME, printf("opening %s\n", lvm_device));
337	if ((lvf = fopen(lvm_device, "r")) == NULL) {
338		DBG(DEBUG_DEVNAME, printf("%s: (%d) %s\n", lvm_device, errno,
339					  strerror(errno)));
340		return 0;
341	}
342
343	while (fgets(buf, sizeof(buf), lvf)) {
344		if (sscanf(buf, "device: %d:%d", &ma, &mi) == 2) {
345			ret = makedev(ma, mi);
346			break;
347		}
348	}
349	fclose(lvf);
350
351	return ret;
352}
353
354static void lvm_probe_all(blkid_cache cache, int only_if_new)
355{
356	DIR		*vg_list;
357	struct dirent	*vg_iter;
358	int		vg_len = strlen(VG_DIR);
359	dev_t		dev;
360
361	if ((vg_list = opendir(VG_DIR)) == NULL)
362		return;
363
364	DBG(DEBUG_DEVNAME, printf("probing LVM devices under %s\n", VG_DIR));
365
366	while ((vg_iter = readdir(vg_list)) != NULL) {
367		DIR		*lv_list;
368		char		*vdirname;
369		char		*vg_name;
370		struct dirent	*lv_iter;
371
372		vg_name = vg_iter->d_name;
373		if (!strcmp(vg_name, ".") || !strcmp(vg_name, ".."))
374			continue;
375		vdirname = malloc(vg_len + strlen(vg_name) + 8);
376		if (!vdirname)
377			goto exit;
378		sprintf(vdirname, "%s/%s/LVs", VG_DIR, vg_name);
379
380		lv_list = opendir(vdirname);
381		free(vdirname);
382		if (lv_list == NULL)
383			continue;
384
385		while ((lv_iter = readdir(lv_list)) != NULL) {
386			char		*lv_name, *lvm_device;
387
388			lv_name = lv_iter->d_name;
389			if (!strcmp(lv_name, ".") || !strcmp(lv_name, ".."))
390				continue;
391
392			lvm_device = malloc(vg_len + strlen(vg_name) +
393					    strlen(lv_name) + 8);
394			if (!lvm_device) {
395				closedir(lv_list);
396				goto exit;
397			}
398			sprintf(lvm_device, "%s/%s/LVs/%s", VG_DIR, vg_name,
399				lv_name);
400			dev = lvm_get_devno(lvm_device);
401			sprintf(lvm_device, "%s/%s", vg_name, lv_name);
402			DBG(DEBUG_DEVNAME, printf("LVM dev %s: devno 0x%04X\n",
403						  lvm_device,
404						  (unsigned int) dev));
405			probe_one(cache, lvm_device, dev, BLKID_PRI_LVM,
406				  only_if_new);
407			free(lvm_device);
408		}
409		closedir(lv_list);
410	}
411exit:
412	closedir(vg_list);
413}
414#endif
415
416#define PROC_EVMS_VOLUMES "/proc/evms/volumes"
417
418static int
419evms_probe_all(blkid_cache cache, int only_if_new)
420{
421	char line[100];
422	int ma, mi, sz, num = 0;
423	FILE *procpt;
424	char device[110];
425
426	procpt = fopen(PROC_EVMS_VOLUMES, "r");
427	if (!procpt)
428		return 0;
429	while (fgets(line, sizeof(line), procpt)) {
430		if (sscanf (line, " %d %d %d %*s %*s %[^\n ]",
431			    &ma, &mi, &sz, device) != 4)
432			continue;
433
434		DBG(DEBUG_DEVNAME, printf("Checking partition %s (%d, %d)\n",
435					  device, ma, mi));
436
437		probe_one(cache, device, makedev(ma, mi), BLKID_PRI_EVMS,
438			  only_if_new);
439		num++;
440	}
441	fclose(procpt);
442	return num;
443}
444
445/*
446 * Read the device data for all available block devices in the system.
447 */
448static int probe_all(blkid_cache cache, int only_if_new)
449{
450	FILE *proc;
451	char line[1024];
452	char ptname0[128], ptname1[128], *ptname = 0;
453	char *ptnames[2];
454	dev_t devs[2];
455	int ma, mi;
456	unsigned long long sz;
457	int lens[2] = { 0, 0 };
458	int which = 0, last = 0;
459
460	ptnames[0] = ptname0;
461	ptnames[1] = ptname1;
462
463	if (!cache)
464		return -BLKID_ERR_PARAM;
465
466	if (cache->bic_flags & BLKID_BIC_FL_PROBED &&
467	    time(0) - cache->bic_time < BLKID_PROBE_INTERVAL)
468		return 0;
469
470	blkid_read_cache(cache);
471#ifdef HAVE_DEVMAPPER
472	dm_probe_all(cache, only_if_new);
473#endif
474	evms_probe_all(cache, only_if_new);
475#ifdef VG_DIR
476	lvm_probe_all(cache, only_if_new);
477#endif
478
479	proc = fopen(PROC_PARTITIONS, "r");
480	if (!proc)
481		return -BLKID_ERR_PROC;
482
483	while (fgets(line, sizeof(line), proc)) {
484		last = which;
485		which ^= 1;
486		ptname = ptnames[which];
487
488		if (sscanf(line, " %d %d %llu %128[^\n ]",
489			   &ma, &mi, &sz, ptname) != 4)
490			continue;
491		devs[which] = makedev(ma, mi);
492
493		DBG(DEBUG_DEVNAME, printf("read partition name %s\n", ptname));
494
495		/* Skip whole disk devs unless they have no partitions
496		 * If we don't have a partition on this dev, also
497		 * check previous dev to see if it didn't have a partn.
498		 * heuristic: partition name ends in a digit.
499		 *
500		 * Skip extended partitions.
501		 * heuristic: size is 1
502		 *
503		 * FIXME: skip /dev/{ida,cciss,rd} whole-disk devs
504		 */
505
506		lens[which] = strlen(ptname);
507		if (isdigit(ptname[lens[which] - 1])) {
508			DBG(DEBUG_DEVNAME,
509			    printf("partition dev %s, devno 0x%04X\n",
510				   ptname, (unsigned int) devs[which]));
511
512			if (sz > 1)
513				probe_one(cache, ptname, devs[which], 0,
514					  only_if_new);
515			lens[which] = 0;
516			lens[last] = 0;
517		} else if (lens[last] && strncmp(ptnames[last], ptname,
518						 lens[last])) {
519			DBG(DEBUG_DEVNAME,
520			    printf("whole dev %s, devno 0x%04X\n",
521				   ptnames[last], (unsigned int) devs[last]));
522			probe_one(cache, ptnames[last], devs[last], 0,
523				  only_if_new);
524			lens[last] = 0;
525		}
526	}
527
528	/* Handle the last device if it wasn't partitioned */
529	if (lens[which])
530		probe_one(cache, ptname, devs[which], 0, only_if_new);
531
532	fclose(proc);
533	blkid_flush_cache(cache);
534	return 0;
535}
536
537int blkid_probe_all(blkid_cache cache)
538{
539	int ret;
540
541	DBG(DEBUG_PROBE, printf("Begin blkid_probe_all()\n"));
542	ret = probe_all(cache, 0);
543	cache->bic_time = time(0);
544	cache->bic_flags |= BLKID_BIC_FL_PROBED;
545	DBG(DEBUG_PROBE, printf("End blkid_probe_all()\n"));
546	return ret;
547}
548
549int blkid_probe_all_new(blkid_cache cache)
550{
551	int ret;
552
553	DBG(DEBUG_PROBE, printf("Begin blkid_probe_all_new()\n"));
554	ret = probe_all(cache, 1);
555	DBG(DEBUG_PROBE, printf("End blkid_probe_all_new()\n"));
556	return ret;
557}
558
559
560#ifdef TEST_PROGRAM
561int main(int argc, char **argv)
562{
563	blkid_cache cache = NULL;
564	int ret;
565
566	blkid_debug_mask = DEBUG_ALL;
567	if (argc != 1) {
568		fprintf(stderr, "Usage: %s\n"
569			"Probe all devices and exit\n", argv[0]);
570		exit(1);
571	}
572	if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
573		fprintf(stderr, "%s: error creating cache (%d)\n",
574			argv[0], ret);
575		exit(1);
576	}
577	if (blkid_probe_all(cache) < 0)
578		printf("%s: error probing devices\n", argv[0]);
579
580	blkid_put_cache(cache);
581	return (0);
582}
583#endif
584