1 /* $NetBSD: dev-cache.c,v 1.4 2009/12/02 00:58:03 haad Exp $ */
2
3 /*
4 * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
5 * Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
6 *
7 * This file is part of LVM2.
8 *
9 * This copyrighted material is made available to anyone wishing to use,
10 * modify, copy, or redistribute it subject to the terms and conditions
11 * of the GNU Lesser General Public License v.2.1.
12 *
13 * You should have received a copy of the GNU Lesser General Public License
14 * along with this program; if not, write to the Free Software Foundation,
15 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
16 */
17
18 #include "lib.h"
19 #include "dev-cache.h"
20 #include "lvm-types.h"
21 #include "btree.h"
22 #include "filter.h"
23 #include "filter-persistent.h"
24 #include "toolcontext.h"
25
26 #include <unistd.h>
27 #include <sys/param.h>
28 #include <dirent.h>
29
30 #ifdef __NetBSD__
31 #include "netbsd.h"
32 #endif
33
34 struct dev_iter {
35 struct btree_iter *current;
36 struct dev_filter *filter;
37 };
38
39 struct dir_list {
40 struct dm_list list;
41 char dir[0];
42 };
43
44 static struct {
45 struct dm_pool *mem;
46 struct dm_hash_table *names;
47 struct btree *devices;
48 struct dm_regex *preferred_names_matcher;
49
50 int has_scanned;
51 struct dm_list dirs;
52 struct dm_list files;
53
54 } _cache;
55
56 #define _alloc(x) dm_pool_zalloc(_cache.mem, (x))
57 #define _free(x) dm_pool_free(_cache.mem, (x))
58 #define _strdup(x) dm_pool_strdup(_cache.mem, (x))
59
60 static int _insert(const char *path, int rec);
61
dev_create_file(const char * filename,struct device * dev,struct str_list * alias,int use_malloc)62 struct device *dev_create_file(const char *filename, struct device *dev,
63 struct str_list *alias, int use_malloc)
64 {
65 int allocate = !dev;
66
67 if (allocate) {
68 if (use_malloc) {
69 if (!(dev = dm_malloc(sizeof(*dev)))) {
70 log_error("struct device allocation failed");
71 return NULL;
72 }
73 if (!(alias = dm_malloc(sizeof(*alias)))) {
74 log_error("struct str_list allocation failed");
75 dm_free(dev);
76 return NULL;
77 }
78 if (!(alias->str = dm_strdup(filename))) {
79 log_error("filename strdup failed");
80 dm_free(dev);
81 dm_free(alias);
82 return NULL;
83 }
84 dev->flags = DEV_ALLOCED;
85 } else {
86 if (!(dev = _alloc(sizeof(*dev)))) {
87 log_error("struct device allocation failed");
88 return NULL;
89 }
90 if (!(alias = _alloc(sizeof(*alias)))) {
91 log_error("struct str_list allocation failed");
92 _free(dev);
93 return NULL;
94 }
95 if (!(alias->str = _strdup(filename))) {
96 log_error("filename strdup failed");
97 return NULL;
98 }
99 }
100 } else if (!(alias->str = dm_strdup(filename))) {
101 log_error("filename strdup failed");
102 return NULL;
103 }
104
105 dev->flags |= DEV_REGULAR;
106 dm_list_init(&dev->aliases);
107 dm_list_add(&dev->aliases, &alias->list);
108 dev->end = UINT64_C(0);
109 dev->dev = 0;
110 dev->fd = -1;
111 dev->open_count = 0;
112 dev->block_size = -1;
113 dev->read_ahead = -1;
114 memset(dev->pvid, 0, sizeof(dev->pvid));
115 dm_list_init(&dev->open_list);
116
117 return dev;
118 }
119
_dev_create(dev_t d)120 static struct device *_dev_create(dev_t d)
121 {
122 struct device *dev;
123
124 if (!(dev = _alloc(sizeof(*dev)))) {
125 log_error("struct device allocation failed");
126 return NULL;
127 }
128 dev->flags = 0;
129 dm_list_init(&dev->aliases);
130 dev->dev = d;
131 dev->fd = -1;
132 dev->open_count = 0;
133 dev->block_size = -1;
134 dev->read_ahead = -1;
135 dev->end = UINT64_C(0);
136 memset(dev->pvid, 0, sizeof(dev->pvid));
137 dm_list_init(&dev->open_list);
138
139 return dev;
140 }
141
dev_set_preferred_name(struct str_list * sl,struct device * dev)142 void dev_set_preferred_name(struct str_list *sl, struct device *dev)
143 {
144 /*
145 * Don't interfere with ordering specified in config file.
146 */
147 if (_cache.preferred_names_matcher)
148 return;
149
150 log_debug("%s: New preferred name", sl->str);
151 dm_list_del(&sl->list);
152 dm_list_add_h(&dev->aliases, &sl->list);
153 }
154
155 /* Return 1 if we prefer path1 else return 0 */
_compare_paths(const char * path0,const char * path1)156 static int _compare_paths(const char *path0, const char *path1)
157 {
158 int slash0 = 0, slash1 = 0;
159 int m0, m1;
160 const char *p;
161 char p0[PATH_MAX], p1[PATH_MAX];
162 char *s0, *s1;
163 struct stat stat0, stat1;
164
165 /*
166 * FIXME Better to compare patterns one-at-a-time against all names.
167 */
168 if (_cache.preferred_names_matcher) {
169 m0 = dm_regex_match(_cache.preferred_names_matcher, path0);
170 m1 = dm_regex_match(_cache.preferred_names_matcher, path1);
171
172 if (m0 != m1) {
173 if (m0 < 0)
174 return 1;
175 if (m1 < 0)
176 return 0;
177 if (m0 < m1)
178 return 1;
179 if (m1 < m0)
180 return 0;
181 }
182 }
183
184 /*
185 * Built-in rules.
186 */
187
188 /* Return the path with fewer slashes */
189 for (p = path0; p++; p = (const char *) strchr(p, '/'))
190 slash0++;
191
192 for (p = path1; p++; p = (const char *) strchr(p, '/'))
193 slash1++;
194
195 if (slash0 < slash1)
196 return 0;
197 if (slash1 < slash0)
198 return 1;
199
200 strncpy(p0, path0, PATH_MAX);
201 strncpy(p1, path1, PATH_MAX);
202 s0 = &p0[0] + 1;
203 s1 = &p1[0] + 1;
204
205 /* We prefer symlinks - they exist for a reason!
206 * So we prefer a shorter path before the first symlink in the name.
207 * FIXME Configuration option to invert this? */
208 while (s0) {
209 s0 = strchr(s0, '/');
210 s1 = strchr(s1, '/');
211 if (s0) {
212 *s0 = '\0';
213 *s1 = '\0';
214 }
215 if (lstat(p0, &stat0)) {
216 log_sys_very_verbose("lstat", p0);
217 return 1;
218 }
219 if (lstat(p1, &stat1)) {
220 log_sys_very_verbose("lstat", p1);
221 return 0;
222 }
223 if (S_ISLNK(stat0.st_mode) && !S_ISLNK(stat1.st_mode))
224 return 0;
225 if (!S_ISLNK(stat0.st_mode) && S_ISLNK(stat1.st_mode))
226 return 1;
227 if (s0) {
228 *s0++ = '/';
229 *s1++ = '/';
230 }
231 }
232
233 /* ASCII comparison */
234 if (strcmp(path0, path1) < 0)
235 return 0;
236 else
237 return 1;
238 }
239
_add_alias(struct device * dev,const char * path)240 static int _add_alias(struct device *dev, const char *path)
241 {
242 struct str_list *sl = _alloc(sizeof(*sl));
243 struct str_list *strl;
244 const char *oldpath;
245 int prefer_old = 1;
246
247 if (!sl)
248 return_0;
249
250 /* Is name already there? */
251 dm_list_iterate_items(strl, &dev->aliases) {
252 if (!strcmp(strl->str, path)) {
253 log_debug("%s: Already in device cache", path);
254 return 1;
255 }
256 }
257
258 if (!(sl->str = dm_pool_strdup(_cache.mem, path)))
259 return_0;
260
261 if (!dm_list_empty(&dev->aliases)) {
262 oldpath = dm_list_item(dev->aliases.n, struct str_list)->str;
263 prefer_old = _compare_paths(path, oldpath);
264 log_debug("%s: Aliased to %s in device cache%s",
265 path, oldpath, prefer_old ? "" : " (preferred name)");
266
267 } else
268 log_debug("%s: Added to device cache", path);
269
270 if (prefer_old)
271 dm_list_add(&dev->aliases, &sl->list);
272 else
273 dm_list_add_h(&dev->aliases, &sl->list);
274
275 return 1;
276 }
277
278 /*
279 * Either creates a new dev, or adds an alias to
280 * an existing dev.
281 */
_insert_dev(const char * path,dev_t d)282 static int _insert_dev(const char *path, dev_t d)
283 {
284 struct device *dev;
285 static dev_t loopfile_count = 0;
286 int loopfile = 0;
287
288 /* Generate pretend device numbers for loopfiles */
289 if (!d) {
290 if (dm_hash_lookup(_cache.names, path))
291 return 1;
292 d = ++loopfile_count;
293 loopfile = 1;
294 }
295
296 /* is this device already registered ? */
297 if (!(dev = (struct device *) btree_lookup(_cache.devices,
298 (uint32_t) d))) {
299 /* create new device */
300 if (loopfile) {
301 if (!(dev = dev_create_file(path, NULL, NULL, 0)))
302 return_0;
303 } else if (!(dev = _dev_create(d)))
304 return_0;
305
306 if (!(btree_insert(_cache.devices, (uint32_t) d, dev))) {
307 log_error("Couldn't insert device into binary tree.");
308 _free(dev);
309 return 0;
310 }
311 }
312
313 if (!loopfile && !_add_alias(dev, path)) {
314 log_error("Couldn't add alias to dev cache.");
315 return 0;
316 }
317
318 if (!dm_hash_insert(_cache.names, path, dev)) {
319 log_error("Couldn't add name to hash in dev cache.");
320 return 0;
321 }
322
323 return 1;
324 }
325
_join(const char * dir,const char * name)326 static char *_join(const char *dir, const char *name)
327 {
328 size_t len = strlen(dir) + strlen(name) + 2;
329 char *r = dm_malloc(len);
330 if (r)
331 snprintf(r, len, "%s/%s", dir, name);
332
333 return r;
334 }
335
336 /*
337 * Get rid of extra slashes in the path string.
338 */
_collapse_slashes(char * str)339 static void _collapse_slashes(char *str)
340 {
341 char *ptr;
342 int was_slash = 0;
343
344 for (ptr = str; *ptr; ptr++) {
345 if (*ptr == '/') {
346 if (was_slash)
347 continue;
348
349 was_slash = 1;
350 } else
351 was_slash = 0;
352 *str++ = *ptr;
353 }
354
355 *str = *ptr;
356 }
357
_insert_dir(const char * dir)358 static int _insert_dir(const char *dir)
359 {
360 int n, dirent_count, r = 1;
361 struct dirent **dirent;
362 char *path;
363
364 dirent_count = scandir(dir, &dirent, NULL, alphasort);
365 if (dirent_count > 0) {
366 for (n = 0; n < dirent_count; n++) {
367 if (dirent[n]->d_name[0] == '.') {
368 free(dirent[n]);
369 continue;
370 }
371
372 if (!(path = _join(dir, dirent[n]->d_name)))
373 return_0;
374
375 _collapse_slashes(path);
376 r &= _insert(path, 1);
377 dm_free(path);
378
379 free(dirent[n]);
380 }
381 free(dirent);
382 }
383
384 return r;
385 }
386
_insert_file(const char * path)387 static int _insert_file(const char *path)
388 {
389 struct stat info;
390
391 if (stat(path, &info) < 0) {
392 log_sys_very_verbose("stat", path);
393 return 0;
394 }
395
396 if (!S_ISREG(info.st_mode)) {
397 log_debug("%s: Not a regular file", path);
398 return 0;
399 }
400
401 if (!_insert_dev(path, 0))
402 return_0;
403
404 return 1;
405 }
406
407 #if defined(__DragonFly__)
408 int dragonfly_check_dev(int major, const char *path);
409 #endif
410
_insert(const char * path,int rec)411 static int _insert(const char *path, int rec)
412 {
413 struct stat info;
414 int r = 0;
415
416 if (stat(path, &info) < 0) {
417 log_sys_very_verbose("stat", path);
418 return 0;
419 }
420
421 if (S_ISDIR(info.st_mode)) { /* add a directory */
422 /* check it's not a symbolic link */
423 if (lstat(path, &info) < 0) {
424 log_sys_very_verbose("lstat", path);
425 return 0;
426 }
427
428 if (S_ISLNK(info.st_mode)) {
429 log_debug("%s: Symbolic link to directory", path);
430 return 0;
431 }
432
433 if (rec)
434 r = _insert_dir(path);
435
436 } else {
437 /* add a device */
438 #ifdef __NetBSD__
439 /*
440 * In NetBSD we have two different types of devices
441 * raw and block. I can insert only existing
442 * raw and block device.
443 */
444 if (S_ISBLK(info.st_mode)) {
445 log_debug("%s: Not a raw device", path);
446 return_0;
447 }
448 if (nbsd_check_dev(MAJOR(info.st_rdev),path) < 0) {
449 log_debug("%s: Not a known raw device", path);
450 return_0;
451 }
452 #elif defined(__DragonFly__)
453 if (dragonfly_check_dev(MAJOR(info.st_rdev),path) < 0) {
454 log_debug("%s: Device not added to cache", path);
455 return_0;
456 }
457
458 #else
459 if (!S_ISBLK(info.st_mode))
460 log_debug("%s: Not a block device", path);
461 #endif
462 if (!_insert_dev(path, info.st_rdev)) {
463 return_0;
464 }
465
466 r = 1;
467 }
468
469 return r;
470 }
471
_full_scan(int dev_scan)472 static void _full_scan(int dev_scan)
473 {
474 struct dir_list *dl;
475
476 if (_cache.has_scanned && !dev_scan)
477 return;
478
479 dm_list_iterate_items(dl, &_cache.dirs)
480 _insert_dir(dl->dir);
481
482 dm_list_iterate_items(dl, &_cache.files)
483 _insert_file(dl->dir);
484
485 _cache.has_scanned = 1;
486 init_full_scan_done(1);
487 }
488
dev_cache_has_scanned(void)489 int dev_cache_has_scanned(void)
490 {
491 return _cache.has_scanned;
492 }
493
dev_cache_scan(int do_scan)494 void dev_cache_scan(int do_scan)
495 {
496 if (!do_scan)
497 _cache.has_scanned = 1;
498 else
499 _full_scan(1);
500 }
501
_init_preferred_names(struct cmd_context * cmd)502 static int _init_preferred_names(struct cmd_context *cmd)
503 {
504 const struct config_node *cn;
505 struct config_value *v;
506 struct dm_pool *scratch = NULL;
507 char **regex;
508 unsigned count = 0;
509 int i, r = 0;
510
511 _cache.preferred_names_matcher = NULL;
512
513 if (!(cn = find_config_tree_node(cmd, "devices/preferred_names")) ||
514 cn->v->type == CFG_EMPTY_ARRAY) {
515 log_very_verbose("devices/preferred_names not found in config file: "
516 "using built-in preferences");
517 return 1;
518 }
519
520 for (v = cn->v; v; v = v->next) {
521 if (v->type != CFG_STRING) {
522 log_error("preferred_names patterns must be enclosed in quotes");
523 return 0;
524 }
525
526 count++;
527 }
528
529 if (!(scratch = dm_pool_create("preferred device name matcher", 1024)))
530 return_0;
531
532 if (!(regex = dm_pool_alloc(scratch, sizeof(*regex) * count))) {
533 log_error("Failed to allocate preferred device name "
534 "pattern list.");
535 goto out;
536 }
537
538 for (v = cn->v, i = count - 1; v; v = v->next, i--) {
539 if (!(regex[i] = dm_pool_strdup(scratch, v->v.str))) {
540 log_error("Failed to allocate a preferred device name "
541 "pattern.");
542 goto out;
543 }
544 }
545
546 if (!(_cache.preferred_names_matcher =
547 dm_regex_create(_cache.mem,(const char **) regex, count))) {
548 log_error("Preferred device name pattern matcher creation failed.");
549 goto out;
550 }
551
552 r = 1;
553
554 out:
555 dm_pool_destroy(scratch);
556
557 return r;
558 }
559
dev_cache_init(struct cmd_context * cmd)560 int dev_cache_init(struct cmd_context *cmd)
561 {
562 _cache.names = NULL;
563 _cache.has_scanned = 0;
564
565 if (!(_cache.mem = dm_pool_create("dev_cache", 10 * 1024)))
566 return_0;
567
568 if (!(_cache.names = dm_hash_create(128))) {
569 dm_pool_destroy(_cache.mem);
570 _cache.mem = 0;
571 return_0;
572 }
573
574 if (!(_cache.devices = btree_create(_cache.mem))) {
575 log_error("Couldn't create binary tree for dev-cache.");
576 goto bad;
577 }
578
579 dm_list_init(&_cache.dirs);
580 dm_list_init(&_cache.files);
581
582 if (!_init_preferred_names(cmd))
583 goto_bad;
584
585 return 1;
586
587 bad:
588 dev_cache_exit();
589 return 0;
590 }
591
_check_closed(struct device * dev)592 static void _check_closed(struct device *dev)
593 {
594 if (dev->fd >= 0)
595 log_error("Device '%s' has been left open.", dev_name(dev));
596 }
597
_check_for_open_devices(void)598 static void _check_for_open_devices(void)
599 {
600 dm_hash_iter(_cache.names, (dm_hash_iterate_fn) _check_closed);
601 }
602
dev_cache_exit(void)603 void dev_cache_exit(void)
604 {
605 if (_cache.names)
606 _check_for_open_devices();
607
608 if (_cache.preferred_names_matcher)
609 _cache.preferred_names_matcher = NULL;
610
611 if (_cache.mem) {
612 dm_pool_destroy(_cache.mem);
613 _cache.mem = NULL;
614 }
615
616 if (_cache.names) {
617 dm_hash_destroy(_cache.names);
618 _cache.names = NULL;
619 }
620
621 _cache.devices = NULL;
622 _cache.has_scanned = 0;
623 dm_list_init(&_cache.dirs);
624 dm_list_init(&_cache.files);
625 }
626
dev_cache_add_dir(const char * path)627 int dev_cache_add_dir(const char *path)
628 {
629 struct dir_list *dl;
630 struct stat st;
631
632 if (stat(path, &st)) {
633 log_error("Ignoring %s: %s", path, strerror(errno));
634 /* But don't fail */
635 return 1;
636 }
637
638 if (!S_ISDIR(st.st_mode)) {
639 log_error("Ignoring %s: Not a directory", path);
640 return 1;
641 }
642
643 if (!(dl = _alloc(sizeof(*dl) + strlen(path) + 1))) {
644 log_error("dir_list allocation failed");
645 return 0;
646 }
647
648 strcpy(dl->dir, path);
649 dm_list_add(&_cache.dirs, &dl->list);
650 return 1;
651 }
652
dev_cache_add_loopfile(const char * path)653 int dev_cache_add_loopfile(const char *path)
654 {
655 struct dir_list *dl;
656 struct stat st;
657
658 if (stat(path, &st)) {
659 log_error("Ignoring %s: %s", path, strerror(errno));
660 /* But don't fail */
661 return 1;
662 }
663
664 if (!S_ISREG(st.st_mode)) {
665 log_error("Ignoring %s: Not a regular file", path);
666 return 1;
667 }
668
669 if (!(dl = _alloc(sizeof(*dl) + strlen(path) + 1))) {
670 log_error("dir_list allocation failed for file");
671 return 0;
672 }
673
674 strcpy(dl->dir, path);
675 dm_list_add(&_cache.files, &dl->list);
676 return 1;
677 }
678
679 /* Check cached device name is still valid before returning it */
680 /* This should be a rare occurrence */
681 /* set quiet if the cache is expected to be out-of-date */
682 /* FIXME Make rest of code pass/cache struct device instead of dev_name */
dev_name_confirmed(struct device * dev,int quiet)683 const char *dev_name_confirmed(struct device *dev, int quiet)
684 {
685 struct stat buf;
686 const char *name;
687 int r;
688
689 if ((dev->flags & DEV_REGULAR))
690 return dev_name(dev);
691
692 while ((r = stat(name = dm_list_item(dev->aliases.n,
693 struct str_list)->str, &buf)) ||
694 (buf.st_rdev != dev->dev)) {
695 if (r < 0) {
696 if (quiet)
697 log_sys_debug("stat", name);
698 else
699 log_sys_error("stat", name);
700 }
701 if (quiet)
702 log_debug("Path %s no longer valid for device(%d,%d)",
703 name, (int) MAJOR(dev->dev),
704 (int) MINOR(dev->dev));
705 else
706 log_error("Path %s no longer valid for device(%d,%d)",
707 name, (int) MAJOR(dev->dev),
708 (int) MINOR(dev->dev));
709
710 /* Remove the incorrect hash entry */
711 dm_hash_remove(_cache.names, name);
712
713 /* Leave list alone if there isn't an alternative name */
714 /* so dev_name will always find something to return. */
715 /* Otherwise add the name to the correct device. */
716 if (dm_list_size(&dev->aliases) > 1) {
717 dm_list_del(dev->aliases.n);
718 if (!r)
719 _insert(name, 0);
720 continue;
721 }
722
723 /* Scanning issues this inappropriately sometimes. */
724 log_debug("Aborting - please provide new pathname for what "
725 "used to be %s", name);
726 return NULL;
727 }
728
729 return dev_name(dev);
730 }
731
dev_cache_get(const char * name,struct dev_filter * f)732 struct device *dev_cache_get(const char *name, struct dev_filter *f)
733 {
734 struct stat buf;
735 struct device *d = (struct device *) dm_hash_lookup(_cache.names, name);
736
737 if (d && (d->flags & DEV_REGULAR))
738 return d;
739
740 /* If the entry's wrong, remove it */
741 if (d && (stat(name, &buf) || (buf.st_rdev != d->dev))) {
742 dm_hash_remove(_cache.names, name);
743 d = NULL;
744 }
745
746 if (!d) {
747 _insert(name, 0);
748 d = (struct device *) dm_hash_lookup(_cache.names, name);
749 if (!d) {
750 _full_scan(0);
751 d = (struct device *) dm_hash_lookup(_cache.names, name);
752 }
753 }
754
755 return (d && (!f || (d->flags & DEV_REGULAR) ||
756 f->passes_filter(f, d))) ? d : NULL;
757 }
758
dev_iter_create(struct dev_filter * f,int dev_scan)759 struct dev_iter *dev_iter_create(struct dev_filter *f, int dev_scan)
760 {
761 struct dev_iter *di = dm_malloc(sizeof(*di));
762
763 if (!di) {
764 log_error("dev_iter allocation failed");
765 return NULL;
766 }
767
768 if (dev_scan && !trust_cache()) {
769 /* Flag gets reset between each command */
770 if (!full_scan_done())
771 persistent_filter_wipe(f); /* Calls _full_scan(1) */
772 } else
773 _full_scan(0);
774
775 di->current = btree_first(_cache.devices);
776 di->filter = f;
777
778 return di;
779 }
780
dev_iter_destroy(struct dev_iter * iter)781 void dev_iter_destroy(struct dev_iter *iter)
782 {
783 dm_free(iter);
784 }
785
_iter_next(struct dev_iter * iter)786 static struct device *_iter_next(struct dev_iter *iter)
787 {
788 struct device *d = btree_get_data(iter->current);
789 iter->current = btree_next(iter->current);
790 return d;
791 }
792
dev_iter_get(struct dev_iter * iter)793 struct device *dev_iter_get(struct dev_iter *iter)
794 {
795 while (iter->current) {
796 struct device *d = _iter_next(iter);
797 if (!iter->filter || (d->flags & DEV_REGULAR) ||
798 iter->filter->passes_filter(iter->filter, d))
799 return d;
800 }
801
802 return NULL;
803 }
804
dev_fd(struct device * dev)805 int dev_fd(struct device *dev)
806 {
807 return dev->fd;
808 }
809
dev_name(const struct device * dev)810 const char *dev_name(const struct device *dev)
811 {
812 return (dev) ? dm_list_item(dev->aliases.n, struct str_list)->str :
813 "unknown device";
814 }
815