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Fix race condition in alarm lock processing noticed by Richard Sharpe <realrichardsha...
[Samba/ekacnet.git] / source3 / lib / util_tdb.c
blob8ceaa4667040817b85d95b44401996c588f5cbdd
1 /*
2 Unix SMB/CIFS implementation.
3 tdb utility functions
4 Copyright (C) Andrew Tridgell 1992-1998
5 Copyright (C) Rafal Szczesniak 2002
6 Copyright (C) Michael Adam 2007
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>.
20 */
21
22 #include "includes.h"
23 #undef malloc
24 #undef realloc
25 #undef calloc
26 #undef strdup
27
28 /* these are little tdb utility functions that are meant to make
29 dealing with a tdb database a little less cumbersome in Samba */
30
31 static SIG_ATOMIC_T gotalarm;
32
33 /***************************************************************
34 Signal function to tell us we timed out.
35 ****************************************************************/
36
37 static void gotalarm_sig(void)
38 {
39 gotalarm = 1;
40 }
41
42 /****************************************************************************
43 Lock a chain with timeout (in seconds).
44 ****************************************************************************/
45
46 static int tdb_chainlock_with_timeout_internal( TDB_CONTEXT *tdb, TDB_DATA key, unsigned int timeout, int rw_type)
47 {
48 /* Allow tdb_chainlock to be interrupted by an alarm. */
49 int ret;
50 gotalarm = 0;
51
52 if (timeout) {
53 CatchSignal(SIGALRM, SIGNAL_CAST gotalarm_sig);
54 tdb_setalarm_sigptr(tdb, &gotalarm);
55 alarm(timeout);
56 }
57
58 if (rw_type == F_RDLCK)
59 ret = tdb_chainlock_read(tdb, key);
60 else
61 ret = tdb_chainlock(tdb, key);
62
63 if (timeout) {
64 alarm(0);
65 tdb_setalarm_sigptr(tdb, NULL);
66 CatchSignal(SIGALRM, SIGNAL_CAST SIG_IGN);
67 if (gotalarm && (ret == -1)) {
68 DEBUG(0,("tdb_chainlock_with_timeout_internal: alarm (%u) timed out for key %s in tdb %s\n",
69 timeout, key.dptr, tdb_name(tdb)));
70 /* TODO: If we time out waiting for a lock, it might
71 * be nice to use F_GETLK to get the pid of the
72 * process currently holding the lock and print that
73 * as part of the debugging message. -- mbp */
74 return -1;
75 }
76 }
77
78 return ret;
79 }
80
81 /****************************************************************************
82 Write lock a chain. Return -1 if timeout or lock failed.
83 ****************************************************************************/
84
85 int tdb_chainlock_with_timeout( TDB_CONTEXT *tdb, TDB_DATA key, unsigned int timeout)
86 {
87 return tdb_chainlock_with_timeout_internal(tdb, key, timeout, F_WRLCK);
88 }
89
90 int tdb_lock_bystring_with_timeout(TDB_CONTEXT *tdb, const char *keyval,
91 int timeout)
92 {
93 TDB_DATA key = string_term_tdb_data(keyval);
94
95 return tdb_chainlock_with_timeout(tdb, key, timeout);
96 }
97
98 /****************************************************************************
99 Read lock a chain by string. Return -1 if timeout or lock failed.
100 ****************************************************************************/
101
102 int tdb_read_lock_bystring_with_timeout(TDB_CONTEXT *tdb, const char *keyval, unsigned int timeout)
103 {
104 TDB_DATA key = string_term_tdb_data(keyval);
105
106 return tdb_chainlock_with_timeout_internal(tdb, key, timeout, F_RDLCK);
107 }
108
109
110
111
112 int tdb_trans_store_bystring(TDB_CONTEXT *tdb, const char *keystr,
113 TDB_DATA data, int flags)
114 {
115 TDB_DATA key = string_term_tdb_data(keystr);
116
117 return tdb_trans_store(tdb, key, data, flags);
118 }
119
120 /****************************************************************************
121 Useful pair of routines for packing/unpacking data consisting of
122 integers and strings.
123 ****************************************************************************/
124
125 static size_t tdb_pack_va(uint8 *buf, int bufsize, const char *fmt, va_list ap)
126 {
127 uint8 bt;
128 uint16 w;
129 uint32 d;
130 int i;
131 void *p;
132 int len;
133 char *s;
134 char c;
135 uint8 *buf0 = buf;
136 const char *fmt0 = fmt;
137 int bufsize0 = bufsize;
138
139 while (*fmt) {
140 switch ((c = *fmt++)) {
141 case 'b': /* unsigned 8-bit integer */
142 len = 1;
143 bt = (uint8)va_arg(ap, int);
144 if (bufsize && bufsize >= len)
145 SSVAL(buf, 0, bt);
146 break;
147 case 'w': /* unsigned 16-bit integer */
148 len = 2;
149 w = (uint16)va_arg(ap, int);
150 if (bufsize && bufsize >= len)
151 SSVAL(buf, 0, w);
152 break;
153 case 'd': /* signed 32-bit integer (standard int in most systems) */
154 len = 4;
155 d = va_arg(ap, uint32);
156 if (bufsize && bufsize >= len)
157 SIVAL(buf, 0, d);
158 break;
159 case 'p': /* pointer */
160 len = 4;
161 p = va_arg(ap, void *);
162 d = p?1:0;
163 if (bufsize && bufsize >= len)
164 SIVAL(buf, 0, d);
165 break;
166 case 'P': /* null-terminated string */
167 s = va_arg(ap,char *);
168 w = strlen(s);
169 len = w + 1;
170 if (bufsize && bufsize >= len)
171 memcpy(buf, s, len);
172 break;
173 case 'f': /* null-terminated string */
174 s = va_arg(ap,char *);
175 w = strlen(s);
176 len = w + 1;
177 if (bufsize && bufsize >= len)
178 memcpy(buf, s, len);
179 break;
180 case 'B': /* fixed-length string */
181 i = va_arg(ap, int);
182 s = va_arg(ap, char *);
183 len = 4+i;
184 if (bufsize && bufsize >= len) {
185 SIVAL(buf, 0, i);
186 memcpy(buf+4, s, i);
187 }
188 break;
189 default:
190 DEBUG(0,("Unknown tdb_pack format %c in %s\n",
191 c, fmt));
192 len = 0;
193 break;
194 }
195
196 buf += len;
197 if (bufsize)
198 bufsize -= len;
199 if (bufsize < 0)
200 bufsize = 0;
201 }
202
203 DEBUG(18,("tdb_pack_va(%s, %d) -> %d\n",
204 fmt0, bufsize0, (int)PTR_DIFF(buf, buf0)));
205
206 return PTR_DIFF(buf, buf0);
207 }
208
209 size_t tdb_pack(uint8 *buf, int bufsize, const char *fmt, ...)
210 {
211 va_list ap;
212 size_t result;
213
214 va_start(ap, fmt);
215 result = tdb_pack_va(buf, bufsize, fmt, ap);
216 va_end(ap);
217 return result;
218 }
219
220 bool tdb_pack_append(TALLOC_CTX *mem_ctx, uint8 **buf, size_t *len,
221 const char *fmt, ...)
222 {
223 va_list ap;
224 size_t len1, len2;
225
226 va_start(ap, fmt);
227 len1 = tdb_pack_va(NULL, 0, fmt, ap);
228 va_end(ap);
229
230 if (mem_ctx != NULL) {
231 *buf = TALLOC_REALLOC_ARRAY(mem_ctx, *buf, uint8,
232 (*len) + len1);
233 } else {
234 *buf = SMB_REALLOC_ARRAY(*buf, uint8, (*len) + len1);
235 }
236
237 if (*buf == NULL) {
238 return False;
239 }
240
241 va_start(ap, fmt);
242 len2 = tdb_pack_va((*buf)+(*len), len1, fmt, ap);
243 va_end(ap);
244
245 if (len1 != len2) {
246 return False;
247 }
248
249 *len += len2;
250
251 return True;
252 }
253
254 /****************************************************************************
255 Useful pair of routines for packing/unpacking data consisting of
256 integers and strings.
257 ****************************************************************************/
258
259 int tdb_unpack(const uint8 *buf, int bufsize, const char *fmt, ...)
260 {
261 va_list ap;
262 uint8 *bt;
263 uint16 *w;
264 uint32 *d;
265 int len;
266 int *i;
267 void **p;
268 char *s, **b, **ps;
269 char c;
270 const uint8 *buf0 = buf;
271 const char *fmt0 = fmt;
272 int bufsize0 = bufsize;
273
274 va_start(ap, fmt);
275
276 while (*fmt) {
277 switch ((c=*fmt++)) {
278 case 'b':
279 len = 1;
280 bt = va_arg(ap, uint8 *);
281 if (bufsize < len)
282 goto no_space;
283 *bt = SVAL(buf, 0);
284 break;
285 case 'w':
286 len = 2;
287 w = va_arg(ap, uint16 *);
288 if (bufsize < len)
289 goto no_space;
290 *w = SVAL(buf, 0);
291 break;
292 case 'd':
293 len = 4;
294 d = va_arg(ap, uint32 *);
295 if (bufsize < len)
296 goto no_space;
297 *d = IVAL(buf, 0);
298 break;
299 case 'p':
300 len = 4;
301 p = va_arg(ap, void **);
302 if (bufsize < len)
303 goto no_space;
304 /*
305 * This isn't a real pointer - only a token (1 or 0)
306 * to mark the fact a pointer is present.
307 */
308
309 *p = (void *)(IVAL(buf, 0) ? (void *)1 : NULL);
310 break;
311 case 'P':
312 /* Return malloc'ed string. */
313 ps = va_arg(ap,char **);
314 len = strlen((const char *)buf) + 1;
315 *ps = SMB_STRDUP((const char *)buf);
316 break;
317 case 'f':
318 s = va_arg(ap,char *);
319 len = strlen((const char *)buf) + 1;
320 if (bufsize < len || len > sizeof(fstring))
321 goto no_space;
322 memcpy(s, buf, len);
323 break;
324 case 'B':
325 i = va_arg(ap, int *);
326 b = va_arg(ap, char **);
327 len = 4;
328 if (bufsize < len)
329 goto no_space;
330 *i = IVAL(buf, 0);
331 if (! *i) {
332 *b = NULL;
333 break;
334 }
335 len += *i;
336 if (bufsize < len)
337 goto no_space;
338 *b = (char *)SMB_MALLOC(*i);
339 if (! *b)
340 goto no_space;
341 memcpy(*b, buf+4, *i);
342 break;
343 default:
344 DEBUG(0,("Unknown tdb_unpack format %c in %s\n",
345 c, fmt));
346
347 len = 0;
348 break;
349 }
350
351 buf += len;
352 bufsize -= len;
353 }
354
355 va_end(ap);
356
357 DEBUG(18,("tdb_unpack(%s, %d) -> %d\n",
358 fmt0, bufsize0, (int)PTR_DIFF(buf, buf0)));
359
360 return PTR_DIFF(buf, buf0);
361
362 no_space:
363 va_end(ap);
364 return -1;
365 }
366
367
368 /****************************************************************************
369 Log tdb messages via DEBUG().
370 ****************************************************************************/
371
372 static void tdb_log(TDB_CONTEXT *tdb, enum tdb_debug_level level, const char *format, ...)
373 {
374 va_list ap;
375 char *ptr = NULL;
376 int ret;
377
378 va_start(ap, format);
379 ret = vasprintf(&ptr, format, ap);
380 va_end(ap);
381
382 if ((ret == -1) || !*ptr)
383 return;
384
385 DEBUG((int)level, ("tdb(%s): %s", tdb_name(tdb) ? tdb_name(tdb) : "unnamed", ptr));
386 SAFE_FREE(ptr);
387 }
388
389 /****************************************************************************
390 Like tdb_open() but also setup a logging function that redirects to
391 the samba DEBUG() system.
392 ****************************************************************************/
393
394 TDB_CONTEXT *tdb_open_log(const char *name, int hash_size, int tdb_flags,
395 int open_flags, mode_t mode)
396 {
397 TDB_CONTEXT *tdb;
398 struct tdb_logging_context log_ctx;
399
400 if (!lp_use_mmap())
401 tdb_flags |= TDB_NOMMAP;
402
403 log_ctx.log_fn = tdb_log;
404 log_ctx.log_private = NULL;
405
406 if ((hash_size == 0) && (name != NULL)) {
407 const char *base = strrchr_m(name, '/');
408 if (base != NULL) {
409 base += 1;
410 }
411 else {
412 base = name;
413 }
414 hash_size = lp_parm_int(-1, "tdb_hashsize", base, 0);
415 }
416
417 tdb = tdb_open_ex(name, hash_size, tdb_flags,
418 open_flags, mode, &log_ctx, NULL);
419 if (!tdb)
420 return NULL;
421
422 return tdb;
423 }
424
425
426 /**
427 * Search across the whole tdb for keys that match the given pattern
428 * return the result as a list of keys
429 *
430 * @param tdb pointer to opened tdb file context
431 * @param pattern searching pattern used by fnmatch(3) functions
432 *
433 * @return list of keys found by looking up with given pattern
434 **/
435 TDB_LIST_NODE *tdb_search_keys(TDB_CONTEXT *tdb, const char* pattern)
436 {
437 TDB_DATA key, next;
438 TDB_LIST_NODE *list = NULL;
439 TDB_LIST_NODE *rec = NULL;
440
441 for (key = tdb_firstkey(tdb); key.dptr; key = next) {
442 /* duplicate key string to ensure null-termination */
443 char *key_str = SMB_STRNDUP((const char *)key.dptr, key.dsize);
444 if (!key_str) {
445 DEBUG(0, ("tdb_search_keys: strndup() failed!\n"));
446 smb_panic("strndup failed!\n");
447 }
448
449 DEBUG(18, ("checking %s for match to pattern %s\n", key_str, pattern));
450
451 next = tdb_nextkey(tdb, key);
452
453 /* do the pattern checking */
454 if (fnmatch(pattern, key_str, 0) == 0) {
455 rec = SMB_MALLOC_P(TDB_LIST_NODE);
456 ZERO_STRUCTP(rec);
457
458 rec->node_key = key;
459
460 DLIST_ADD_END(list, rec, TDB_LIST_NODE *);
461
462 DEBUG(18, ("checking %s matched pattern %s\n", key_str, pattern));
463 } else {
464 free(key.dptr);
465 }
466
467 /* free duplicated key string */
468 free(key_str);
469 }
470
471 return list;
472
473 }
474
475
476 /**
477 * Free the list returned by tdb_search_keys
478 *
479 * @param node list of results found by tdb_search_keys
480 **/
481 void tdb_search_list_free(TDB_LIST_NODE* node)
482 {
483 TDB_LIST_NODE *next_node;
484
485 while (node) {
486 next_node = node->next;
487 SAFE_FREE(node->node_key.dptr);
488 SAFE_FREE(node);
489 node = next_node;
490 };
491 }
492
493 /****************************************************************************
494 tdb_store, wrapped in a transaction. This way we make sure that a process
495 that dies within writing does not leave a corrupt tdb behind.
496 ****************************************************************************/
497
498 int tdb_trans_store(struct tdb_context *tdb, TDB_DATA key, TDB_DATA dbuf,
499 int flag)
500 {
501 int res;
502
503 if ((res = tdb_transaction_start(tdb)) != 0) {
504 DEBUG(5, ("tdb_transaction_start failed\n"));
505 return res;
506 }
507
508 if ((res = tdb_store(tdb, key, dbuf, flag)) != 0) {
509 DEBUG(10, ("tdb_store failed\n"));
510 if (tdb_transaction_cancel(tdb) != 0) {
511 smb_panic("Cancelling transaction failed");
512 }
513 return res;
514 }
515
516 if ((res = tdb_transaction_commit(tdb)) != 0) {
517 DEBUG(5, ("tdb_transaction_commit failed\n"));
518 }
519
520 return res;
521 }
522
523 /****************************************************************************
524 tdb_delete, wrapped in a transaction. This way we make sure that a process
525 that dies within deleting does not leave a corrupt tdb behind.
526 ****************************************************************************/
527
528 int tdb_trans_delete(struct tdb_context *tdb, TDB_DATA key)
529 {
530 int res;
531
532 if ((res = tdb_transaction_start(tdb)) != 0) {
533 DEBUG(5, ("tdb_transaction_start failed\n"));
534 return res;
535 }
536
537 if ((res = tdb_delete(tdb, key)) != 0) {
538 DEBUG(10, ("tdb_delete failed\n"));
539 if (tdb_transaction_cancel(tdb) != 0) {
540 smb_panic("Cancelling transaction failed");
541 }
542 return res;
543 }
544
545 if ((res = tdb_transaction_commit(tdb)) != 0) {
546 DEBUG(5, ("tdb_transaction_commit failed\n"));
547 }
548
549 return res;
550 }
551
552 /*
553 Log tdb messages via DEBUG().
554 */
555 static void tdb_wrap_log(TDB_CONTEXT *tdb, enum tdb_debug_level level,
556 const char *format, ...) PRINTF_ATTRIBUTE(3,4);
557
558 static void tdb_wrap_log(TDB_CONTEXT *tdb, enum tdb_debug_level level,
559 const char *format, ...)
560 {
561 va_list ap;
562 char *ptr = NULL;
563 int debuglevel = 0;
564 int ret;
565
566 switch (level) {
567 case TDB_DEBUG_FATAL:
568 debuglevel = 0;
569 break;
570 case TDB_DEBUG_ERROR:
571 debuglevel = 1;
572 break;
573 case TDB_DEBUG_WARNING:
574 debuglevel = 2;
575 break;
576 case TDB_DEBUG_TRACE:
577 debuglevel = 5;
578 break;
579 default:
580 debuglevel = 0;
581 }
582
583 va_start(ap, format);
584 ret = vasprintf(&ptr, format, ap);
585 va_end(ap);
586
587 if (ret != -1) {
588 const char *name = tdb_name(tdb);
589 DEBUG(debuglevel, ("tdb(%s): %s", name ? name : "unnamed", ptr));
590 free(ptr);
591 }
592 }
593
594 static struct tdb_wrap *tdb_list;
595
596 /* destroy the last connection to a tdb */
597 static int tdb_wrap_destructor(struct tdb_wrap *w)
598 {
599 tdb_close(w->tdb);
600 DLIST_REMOVE(tdb_list, w);
601 return 0;
602 }
603
604 /*
605 wrapped connection to a tdb database
606 to close just talloc_free() the tdb_wrap pointer
607 */
608 struct tdb_wrap *tdb_wrap_open(TALLOC_CTX *mem_ctx,
609 const char *name, int hash_size, int tdb_flags,
610 int open_flags, mode_t mode)
611 {
612 struct tdb_wrap *w;
613 struct tdb_logging_context log_ctx;
614 log_ctx.log_fn = tdb_wrap_log;
615
616 if (!lp_use_mmap())
617 tdb_flags |= TDB_NOMMAP;
618
619 for (w=tdb_list;w;w=w->next) {
620 if (strcmp(name, w->name) == 0) {
621 /*
622 * Yes, talloc_reference is exactly what we want
623 * here. Otherwise we would have to implement our own
624 * reference counting.
625 */
626 return talloc_reference(mem_ctx, w);
627 }
628 }
629
630 w = talloc(mem_ctx, struct tdb_wrap);
631 if (w == NULL) {
632 return NULL;
633 }
634
635 if (!(w->name = talloc_strdup(w, name))) {
636 talloc_free(w);
637 return NULL;
638 }
639
640 if ((hash_size == 0) && (name != NULL)) {
641 const char *base = strrchr_m(name, '/');
642 if (base != NULL) {
643 base += 1;
644 }
645 else {
646 base = name;
647 }
648 hash_size = lp_parm_int(-1, "tdb_hashsize", base, 0);
649 }
650
651 w->tdb = tdb_open_ex(name, hash_size, tdb_flags,
652 open_flags, mode, &log_ctx, NULL);
653 if (w->tdb == NULL) {
654 talloc_free(w);
655 return NULL;
656 }
657
658 talloc_set_destructor(w, tdb_wrap_destructor);
659
660 DLIST_ADD(tdb_list, w);
661
662 return w;
663 }
664
665 NTSTATUS map_nt_error_from_tdb(enum TDB_ERROR err)
666 {
667 struct { enum TDB_ERROR err; NTSTATUS status; } map[] =
668 { { TDB_SUCCESS, NT_STATUS_OK },
669 { TDB_ERR_CORRUPT, NT_STATUS_INTERNAL_DB_CORRUPTION },
670 { TDB_ERR_IO, NT_STATUS_UNEXPECTED_IO_ERROR },
671 { TDB_ERR_OOM, NT_STATUS_NO_MEMORY },
672 { TDB_ERR_EXISTS, NT_STATUS_OBJECT_NAME_COLLISION },
673
674 /*
675 * TDB_ERR_LOCK is very broad, we could for example
676 * distinguish between fcntl locks and invalid lock
677 * sequences. So NT_STATUS_FILE_LOCK_CONFLICT is a
678 * compromise.
679 */
680 { TDB_ERR_LOCK, NT_STATUS_FILE_LOCK_CONFLICT },
681 /*
682 * The next two ones in the enum are not actually used
683 */
684 { TDB_ERR_NOLOCK, NT_STATUS_FILE_LOCK_CONFLICT },
685 { TDB_ERR_LOCK_TIMEOUT, NT_STATUS_FILE_LOCK_CONFLICT },
686 { TDB_ERR_NOEXIST, NT_STATUS_NOT_FOUND },
687 { TDB_ERR_EINVAL, NT_STATUS_INVALID_PARAMETER },
688 { TDB_ERR_RDONLY, NT_STATUS_ACCESS_DENIED }
689 };
690
691 int i;
692
693 for (i=0; i < sizeof(map) / sizeof(map[0]); i++) {
694 if (err == map[i].err) {
695 return map[i].status;
696 }
697 }
698
699 return NT_STATUS_INTERNAL_ERROR;
700 }
701
702
703 /*********************************************************************
704 * the following is a generic validation mechanism for tdbs.
705 *********************************************************************/
706
707 /*
708 * internal validation function, executed by the child.
709 */
710 static int tdb_validate_child(struct tdb_context *tdb,
711 tdb_validate_data_func validate_fn)
712 {
713 int ret = 1;
714 int num_entries = 0;
715 struct tdb_validation_status v_status;
716
717 v_status.tdb_error = False;
718 v_status.bad_freelist = False;
719 v_status.bad_entry = False;
720 v_status.unknown_key = False;
721 v_status.success = True;
722
723 if (!tdb) {
724 v_status.tdb_error = True;
725 v_status.success = False;
726 goto out;
727 }
728
729 /* Check if the tdb's freelist is good. */
730 if (tdb_validate_freelist(tdb, &num_entries) == -1) {
731 v_status.bad_freelist = True;
732 v_status.success = False;
733 goto out;
734 }
735
736 DEBUG(10,("tdb_validate_child: tdb %s freelist has %d entries\n",
737 tdb_name(tdb), num_entries));
738
739 /* Now traverse the tdb to validate it. */
740 num_entries = tdb_traverse(tdb, validate_fn, (void *)&v_status);
741 if (!v_status.success) {
742 goto out;
743 } else if (num_entries == -1) {
744 v_status.tdb_error = True;
745 v_status.success = False;
746 goto out;
747 }
748
749 DEBUG(10,("tdb_validate_child: tdb %s is good with %d entries\n",
750 tdb_name(tdb), num_entries));
751 ret = 0; /* Cache is good. */
752
753 out:
754 DEBUG(10, ("tdb_validate_child: summary of validation status:\n"));
755 DEBUGADD(10,(" * tdb error: %s\n", v_status.tdb_error ? "yes" : "no"));
756 DEBUGADD(10,(" * bad freelist: %s\n",v_status.bad_freelist?"yes":"no"));
757 DEBUGADD(10,(" * bad entry: %s\n", v_status.bad_entry ? "yes" : "no"));
758 DEBUGADD(10,(" * unknown key: %s\n", v_status.unknown_key?"yes":"no"));
759 DEBUGADD(10,(" => overall success: %s\n", v_status.success?"yes":"no"));
760
761 return ret;
762 }
763
764 /*
765 * tdb validation function.
766 * returns 0 if tdb is ok, != 0 if it isn't.
767 * this function expects an opened tdb.
768 */
769 int tdb_validate(struct tdb_context *tdb, tdb_validate_data_func validate_fn)
770 {
771 pid_t child_pid = -1;
772 int child_status = 0;
773 int wait_pid = 0;
774 int ret = 1;
775
776 if (tdb == NULL) {
777 DEBUG(1, ("Error: tdb_validate called with tdb == NULL\n"));
778 return ret;
779 }
780
781 DEBUG(5, ("tdb_validate called for tdb '%s'\n", tdb_name(tdb)));
782
783 /* fork and let the child do the validation.
784 * benefit: no need to twist signal handlers and panic functions.
785 * just let the child panic. we catch the signal. */
786
787 DEBUG(10, ("tdb_validate: forking to let child do validation.\n"));
788 child_pid = sys_fork();
789 if (child_pid == 0) {
790 /* child code */
791 DEBUG(10, ("tdb_validate (validation child): created\n"));
792 DEBUG(10, ("tdb_validate (validation child): "
793 "calling tdb_validate_child\n"));
794 exit(tdb_validate_child(tdb, validate_fn));
795 }
796 else if (child_pid < 0) {
797 DEBUG(1, ("tdb_validate: fork for validation failed.\n"));
798 goto done;
799 }
800
801 /* parent */
802
803 DEBUG(10, ("tdb_validate: fork succeeded, child PID = %d\n",child_pid));
804
805 DEBUG(10, ("tdb_validate: waiting for child to finish...\n"));
806 while ((wait_pid = sys_waitpid(child_pid, &child_status, 0)) < 0) {
807 if (errno == EINTR) {
808 DEBUG(10, ("tdb_validate: got signal during waitpid, "
809 "retrying\n"));
810 errno = 0;
811 continue;
812 }
813 DEBUG(1, ("tdb_validate: waitpid failed with error '%s'.\n",
814 strerror(errno)));
815 goto done;
816 }
817 if (wait_pid != child_pid) {
818 DEBUG(1, ("tdb_validate: waitpid returned pid %d, "
819 "but %d was expected\n", wait_pid, child_pid));
820 goto done;
821 }
822
823 DEBUG(10, ("tdb_validate: validating child returned.\n"));
824 if (WIFEXITED(child_status)) {
825 DEBUG(10, ("tdb_validate: child exited, code %d.\n",
826 WEXITSTATUS(child_status)));
827 ret = WEXITSTATUS(child_status);
828 }
829 if (WIFSIGNALED(child_status)) {
830 DEBUG(10, ("tdb_validate: child terminated by signal %d\n",
831 WTERMSIG(child_status)));
832 #ifdef WCOREDUMP
833 if (WCOREDUMP(child_status)) {
834 DEBUGADD(10, ("core dumped\n"));
835 }
836 #endif
837 ret = WTERMSIG(child_status);
838 }
839 if (WIFSTOPPED(child_status)) {
840 DEBUG(10, ("tdb_validate: child was stopped by signal %d\n",
841 WSTOPSIG(child_status)));
842 ret = WSTOPSIG(child_status);
843 }
844
845 done:
846 DEBUG(5, ("tdb_validate returning code '%d' for tdb '%s'\n", ret,
847 tdb_name(tdb)));
848
849 return ret;
850 }
851
852 /*
853 * tdb validation function.
854 * returns 0 if tdb is ok, != 0 if it isn't.
855 * this is a wrapper around the actual validation function that opens and closes
856 * the tdb.
857 */
858 int tdb_validate_open(const char *tdb_path, tdb_validate_data_func validate_fn)
859 {
860 TDB_CONTEXT *tdb = NULL;
861 int ret = 1;
862
863 DEBUG(5, ("tdb_validate_open called for tdb '%s'\n", tdb_path));
864
865 tdb = tdb_open_log(tdb_path, 0, TDB_DEFAULT, O_RDONLY, 0);
866 if (!tdb) {
867 DEBUG(1, ("Error opening tdb %s\n", tdb_path));
868 return ret;
869 }
870
871 ret = tdb_validate(tdb, validate_fn);
872 tdb_close(tdb);
873 return ret;
874 }
875
876 /*
877 * tdb backup function and helpers for tdb_validate wrapper with backup
878 * handling.
879 */
880
881 /* this structure eliminates the need for a global overall status for
882 * the traverse-copy */
883 struct tdb_copy_data {
884 struct tdb_context *dst;
885 bool success;
886 };
887
888 static int traverse_copy_fn(struct tdb_context *tdb, TDB_DATA key,
889 TDB_DATA dbuf, void *private_data)
890 {
891 struct tdb_copy_data *data = (struct tdb_copy_data *)private_data;
892
893 if (tdb_store(data->dst, key, dbuf, TDB_INSERT) != 0) {
894 DEBUG(4, ("Failed to insert into %s: %s\n", tdb_name(data->dst),
895 strerror(errno)));
896 data->success = False;
897 return 1;
898 }
899 return 0;
900 }
901
902 static int tdb_copy(struct tdb_context *src, struct tdb_context *dst)
903 {
904 struct tdb_copy_data data;
905 int count;
906
907 data.dst = dst;
908 data.success = True;
909
910 count = tdb_traverse(src, traverse_copy_fn, (void *)(&data));
911 if ((count < 0) || (data.success == False)) {
912 return -1;
913 }
914 return count;
915 }
916
917 static int tdb_verify_basic(struct tdb_context *tdb)
918 {
919 return tdb_traverse(tdb, NULL, NULL);
920 }
921
922 /* this backup function is essentially taken from lib/tdb/tools/tdbbackup.tdb
923 */
924 static int tdb_backup(TALLOC_CTX *ctx, const char *src_path,
925 const char *dst_path, int hash_size)
926 {
927 struct tdb_context *src_tdb = NULL;
928 struct tdb_context *dst_tdb = NULL;
929 char *tmp_path = NULL;
930 struct stat st;
931 int count1, count2;
932 int saved_errno = 0;
933 int ret = -1;
934
935 if (stat(src_path, &st) != 0) {
936 DEBUG(3, ("Could not stat '%s': %s\n", src_path,
937 strerror(errno)));
938 goto done;
939 }
940
941 /* open old tdb RDWR - so we can lock it */
942 src_tdb = tdb_open_log(src_path, 0, TDB_DEFAULT, O_RDWR, 0);
943 if (src_tdb == NULL) {
944 DEBUG(3, ("Failed to open tdb '%s'\n", src_path));
945 goto done;
946 }
947
948 if (tdb_lockall(src_tdb) != 0) {
949 DEBUG(3, ("Failed to lock tdb '%s'\n", src_path));
950 goto done;
951 }
952
953 tmp_path = talloc_asprintf(ctx, "%s%s", dst_path, ".tmp");
954 unlink(tmp_path);
955 dst_tdb = tdb_open_log(tmp_path,
956 hash_size ? hash_size : tdb_hash_size(src_tdb),
957 TDB_DEFAULT, O_RDWR | O_CREAT | O_EXCL,
958 st.st_mode & 0777);
959 if (dst_tdb == NULL) {
960 DEBUG(3, ("Error creating tdb '%s': %s\n", tmp_path,
961 strerror(errno)));
962 saved_errno = errno;
963 unlink(tmp_path);
964 goto done;
965 }
966
967 count1 = tdb_copy(src_tdb, dst_tdb);
968 if (count1 < 0) {
969 DEBUG(3, ("Failed to copy tdb '%s': %s\n", src_path,
970 strerror(errno)));
971 tdb_close(dst_tdb);
972 goto done;
973 }
974
975 /* reopen ro and do basic verification */
976 tdb_close(dst_tdb);
977 dst_tdb = tdb_open_log(tmp_path, 0, TDB_DEFAULT, O_RDONLY, 0);
978 if (!dst_tdb) {
979 DEBUG(3, ("Failed to reopen tdb '%s': %s\n", tmp_path,
980 strerror(errno)));
981 goto done;
982 }
983 count2 = tdb_verify_basic(dst_tdb);
984 if (count2 != count1) {
985 DEBUG(3, ("Failed to verify result of copying tdb '%s'.\n",
986 src_path));
987 tdb_close(dst_tdb);
988 goto done;
989 }
990
991 DEBUG(10, ("tdb_backup: successfully copied %d entries\n", count1));
992
993 /* make sure the new tdb has reached stable storage
994 * then rename it to its destination */
995 fsync(tdb_fd(dst_tdb));
996 tdb_close(dst_tdb);
997 unlink(dst_path);
998 if (rename(tmp_path, dst_path) != 0) {
999 DEBUG(3, ("Failed to rename '%s' to '%s': %s\n",
1000 tmp_path, dst_path, strerror(errno)));
1001 goto done;
1002 }
1003
1004 /* success */
1005 ret = 0;
1006
1007 done:
1008 if (src_tdb != NULL) {
1009 tdb_close(src_tdb);
1010 }
1011 if (tmp_path != NULL) {
1012 unlink(tmp_path);
1013 TALLOC_FREE(tmp_path);
1014 }
1015 if (saved_errno != 0) {
1016 errno = saved_errno;
1017 }
1018 return ret;
1019 }
1020
1021 static int rename_file_with_suffix(TALLOC_CTX *ctx, const char *path,
1022 const char *suffix)
1023 {
1024 int ret = -1;
1025 char *dst_path;
1026
1027 dst_path = talloc_asprintf(ctx, "%s%s", path, suffix);
1028
1029 ret = (rename(path, dst_path) != 0);
1030
1031 if (ret == 0) {
1032 DEBUG(5, ("moved '%s' to '%s'\n", path, dst_path));
1033 } else if (errno == ENOENT) {
1034 DEBUG(3, ("file '%s' does not exist - so not moved\n", path));
1035 ret = 0;
1036 } else {
1037 DEBUG(3, ("error renaming %s to %s: %s\n", path, dst_path,
1038 strerror(errno)));
1039 }
1040
1041 TALLOC_FREE(dst_path);
1042 return ret;
1043 }
1044
1045 /*
1046 * do a backup of a tdb, moving the destination out of the way first
1047 */
1048 static int tdb_backup_with_rotate(TALLOC_CTX *ctx, const char *src_path,
1049 const char *dst_path, int hash_size,
1050 const char *rotate_suffix,
1051 bool retry_norotate_if_nospc,
1052 bool rename_as_last_resort_if_nospc)
1053 {
1054 int ret;
1055
1056 rename_file_with_suffix(ctx, dst_path, rotate_suffix);
1057
1058 ret = tdb_backup(ctx, src_path, dst_path, hash_size);
1059
1060 if (ret != 0) {
1061 DEBUG(10, ("backup of %s failed: %s\n", src_path, strerror(errno)));
1062 }
1063 if ((ret != 0) && (errno == ENOSPC) && retry_norotate_if_nospc)
1064 {
1065 char *rotate_path = talloc_asprintf(ctx, "%s%s", dst_path,
1066 rotate_suffix);
1067 DEBUG(10, ("backup of %s failed due to lack of space\n",
1068 src_path));
1069 DEBUGADD(10, ("trying to free some space by removing rotated "
1070 "dst %s\n", rotate_path));
1071 if (unlink(rotate_path) == -1) {
1072 DEBUG(10, ("unlink of %s failed: %s\n", rotate_path,
1073 strerror(errno)));
1074 } else {
1075 ret = tdb_backup(ctx, src_path, dst_path, hash_size);
1076 }
1077 TALLOC_FREE(rotate_path);
1078 }
1079
1080 if ((ret != 0) && (errno == ENOSPC) && rename_as_last_resort_if_nospc)
1081 {
1082 DEBUG(10, ("backup of %s failed due to lack of space\n",
1083 src_path));
1084 DEBUGADD(10, ("using 'rename' as a last resort\n"));
1085 ret = rename(src_path, dst_path);
1086 }
1087
1088 return ret;
1089 }
1090
1091 /*
1092 * validation function with backup handling:
1093 *
1094 * - calls tdb_validate
1095 * - if the tdb is ok, create a backup "name.bak", possibly moving
1096 * existing backup to name.bak.old,
1097 * return 0 (success) even if the backup fails
1098 * - if the tdb is corrupt:
1099 * - move the tdb to "name.corrupt"
1100 * - check if there is valid backup.
1101 * if so, restore the backup.
1102 * if restore is successful, return 0 (success),
1103 * - otherwise return -1 (failure)
1104 */
1105 int tdb_validate_and_backup(const char *tdb_path,
1106 tdb_validate_data_func validate_fn)
1107 {
1108 int ret = -1;
1109 const char *backup_suffix = ".bak";
1110 const char *corrupt_suffix = ".corrupt";
1111 const char *rotate_suffix = ".old";
1112 char *tdb_path_backup;
1113 struct stat st;
1114 TALLOC_CTX *ctx = NULL;
1115
1116 ctx = talloc_new(NULL);
1117 if (ctx == NULL) {
1118 DEBUG(0, ("tdb_validate_and_backup: out of memory\n"));
1119 goto done;
1120 }
1121
1122 tdb_path_backup = talloc_asprintf(ctx, "%s%s", tdb_path, backup_suffix);
1123
1124 ret = tdb_validate_open(tdb_path, validate_fn);
1125
1126 if (ret == 0) {
1127 DEBUG(1, ("tdb '%s' is valid\n", tdb_path));
1128 ret = tdb_backup_with_rotate(ctx, tdb_path, tdb_path_backup, 0,
1129 rotate_suffix, True, False);
1130 if (ret != 0) {
1131 DEBUG(1, ("Error creating backup of tdb '%s'\n",
1132 tdb_path));
1133 /* the actual validation was successful: */
1134 ret = 0;
1135 } else {
1136 DEBUG(1, ("Created backup '%s' of tdb '%s'\n",
1137 tdb_path_backup, tdb_path));
1138 }
1139 } else {
1140 DEBUG(1, ("tdb '%s' is invalid\n", tdb_path));
1141
1142 ret =stat(tdb_path_backup, &st);
1143 if (ret != 0) {
1144 DEBUG(5, ("Could not stat '%s': %s\n", tdb_path_backup,
1145 strerror(errno)));
1146 DEBUG(1, ("No backup found.\n"));
1147 } else {
1148 DEBUG(1, ("backup '%s' found.\n", tdb_path_backup));
1149 ret = tdb_validate_open(tdb_path_backup, validate_fn);
1150 if (ret != 0) {
1151 DEBUG(1, ("Backup '%s' is invalid.\n",
1152 tdb_path_backup));
1153 }
1154 }
1155
1156 if (ret != 0) {
1157 int renamed = rename_file_with_suffix(ctx, tdb_path,
1158 corrupt_suffix);
1159 if (renamed != 0) {
1160 DEBUG(1, ("Error moving tdb to '%s%s'\n",
1161 tdb_path, corrupt_suffix));
1162 } else {
1163 DEBUG(1, ("Corrupt tdb stored as '%s%s'\n",
1164 tdb_path, corrupt_suffix));
1165 }
1166 goto done;
1167 }
1168
1169 DEBUG(1, ("valid backup '%s' found\n", tdb_path_backup));
1170 ret = tdb_backup_with_rotate(ctx, tdb_path_backup, tdb_path, 0,
1171 corrupt_suffix, True, True);
1172 if (ret != 0) {
1173 DEBUG(1, ("Error restoring backup from '%s'\n",
1174 tdb_path_backup));
1175 } else {
1176 DEBUG(1, ("Restored tdb backup from '%s'\n",
1177 tdb_path_backup));
1178 }
1179 }
1180
1181 done:
1182 TALLOC_FREE(ctx);
1183 return ret;
1184 }