source: vendor/current/source3/lib/tdb_validate.c

Last change on this file was 988, checked in by Silvan Scherrer, 9 years ago

Samba Server: update vendor to version 4.4.3
File size: 13.7 KB
Line 
1/*
2 * Unix SMB/CIFS implementation.
3 *
4 * A general tdb content validation mechanism
5 *
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#include "system/filesys.h"
24#include "util_tdb.h"
25#include "tdb_validate.h"
26
27/*
28 * internal validation function, executed by the child.
29 */
30static int tdb_validate_child(struct tdb_context *tdb,
31 tdb_validate_data_func validate_fn)
32{
33 int ret = 1;
34 int num_entries = 0;
35 struct tdb_validation_status v_status;
36
37 v_status.tdb_error = False;
38 v_status.bad_freelist = False;
39 v_status.bad_entry = False;
40 v_status.unknown_key = False;
41 v_status.success = True;
42
43 if (!tdb) {
44 v_status.tdb_error = True;
45 v_status.success = False;
46 goto out;
47 }
48
49 /*
50 * we can simplify this by passing a check function,
51 * but I don't want to change all the callers...
52 */
53 ret = tdb_check(tdb, NULL, NULL);
54 if (ret != 0) {
55 v_status.tdb_error = True;
56 v_status.success = False;
57 goto out;
58 }
59
60 /* Check if the tdb's freelist is good. */
61 if (tdb_validate_freelist(tdb, &num_entries) == -1) {
62 v_status.bad_freelist = True;
63 v_status.success = False;
64 goto out;
65 }
66
67 DEBUG(10,("tdb_validate_child: tdb %s freelist has %d entries\n",
68 tdb_name(tdb), num_entries));
69
70 /* Now traverse the tdb to validate it. */
71 num_entries = tdb_traverse(tdb, validate_fn, (void *)&v_status);
72 if (!v_status.success) {
73 goto out;
74 } else if (num_entries < 0) {
75 v_status.tdb_error = True;
76 v_status.success = False;
77 goto out;
78 }
79
80 DEBUG(10,("tdb_validate_child: tdb %s is good with %d entries\n",
81 tdb_name(tdb), num_entries));
82 ret = 0; /* Cache is good. */
83
84out:
85 DEBUG(10, ("tdb_validate_child: summary of validation status:\n"));
86 DEBUGADD(10,(" * tdb error: %s\n", v_status.tdb_error ? "yes" : "no"));
87 DEBUGADD(10,(" * bad freelist: %s\n",v_status.bad_freelist?"yes":"no"));
88 DEBUGADD(10,(" * bad entry: %s\n", v_status.bad_entry ? "yes" : "no"));
89 DEBUGADD(10,(" * unknown key: %s\n", v_status.unknown_key?"yes":"no"));
90 DEBUGADD(10,(" => overall success: %s\n", v_status.success?"yes":"no"));
91
92 return ret;
93}
94
95/*
96 * tdb validation function.
97 * returns 0 if tdb is ok, != 0 if it isn't.
98 * this function expects an opened tdb.
99 */
100int tdb_validate(struct tdb_context *tdb, tdb_validate_data_func validate_fn)
101{
102 pid_t child_pid = -1;
103 int child_status = 0;
104 int wait_pid = 0;
105 int ret = 1;
106
107 if (tdb == NULL) {
108 DEBUG(1, ("Error: tdb_validate called with tdb == NULL\n"));
109 return ret;
110 }
111
112 DEBUG(5, ("tdb_validate called for tdb '%s'\n", tdb_name(tdb)));
113
114 /* fork and let the child do the validation.
115 * benefit: no need to twist signal handlers and panic functions.
116 * just let the child panic. we catch the signal. */
117
118 DEBUG(10, ("tdb_validate: forking to let child do validation.\n"));
119 child_pid = fork();
120 if (child_pid == 0) {
121 /* child code */
122 DEBUG(10, ("tdb_validate (validation child): created\n"));
123 DEBUG(10, ("tdb_validate (validation child): "
124 "calling tdb_validate_child\n"));
125 exit(tdb_validate_child(tdb, validate_fn));
126 }
127 else if (child_pid < 0) {
128 DEBUG(1, ("tdb_validate: fork for validation failed.\n"));
129 goto done;
130 }
131
132 /* parent */
133
134 DEBUG(10, ("tdb_validate: fork succeeded, child PID = %u\n",
135 (unsigned int)child_pid));
136
137 DEBUG(10, ("tdb_validate: waiting for child to finish...\n"));
138 while ((wait_pid = sys_waitpid(child_pid, &child_status, 0)) < 0) {
139 if (errno == EINTR) {
140 DEBUG(10, ("tdb_validate: got signal during waitpid, "
141 "retrying\n"));
142 errno = 0;
143 continue;
144 }
145 DEBUG(1, ("tdb_validate: waitpid failed with error '%s'.\n",
146 strerror(errno)));
147 goto done;
148 }
149 if (wait_pid != child_pid) {
150 DEBUG(1, ("tdb_validate: waitpid returned pid %d, "
151 "but %u was expected\n", wait_pid, (unsigned int)child_pid));
152 goto done;
153 }
154
155 DEBUG(10, ("tdb_validate: validating child returned.\n"));
156 if (WIFEXITED(child_status)) {
157 DEBUG(10, ("tdb_validate: child exited, code %d.\n",
158 WEXITSTATUS(child_status)));
159 ret = WEXITSTATUS(child_status);
160 }
161 if (WIFSIGNALED(child_status)) {
162 DEBUG(10, ("tdb_validate: child terminated by signal %d\n",
163 WTERMSIG(child_status)));
164#ifdef WCOREDUMP
165 if (WCOREDUMP(child_status)) {
166 DEBUGADD(10, ("core dumped\n"));
167 }
168#endif
169 ret = WTERMSIG(child_status);
170 }
171 if (WIFSTOPPED(child_status)) {
172 DEBUG(10, ("tdb_validate: child was stopped by signal %d\n",
173 WSTOPSIG(child_status)));
174 ret = WSTOPSIG(child_status);
175 }
176
177done:
178 DEBUG(5, ("tdb_validate returning code '%d' for tdb '%s'\n", ret,
179 tdb_name(tdb)));
180
181 return ret;
182}
183
184/*
185 * tdb validation function.
186 * returns 0 if tdb is ok, != 0 if it isn't.
187 * this is a wrapper around the actual validation function that opens and closes
188 * the tdb.
189 */
190int tdb_validate_open(const char *tdb_path, tdb_validate_data_func validate_fn)
191{
192 TDB_CONTEXT *tdb = NULL;
193 int ret = 1;
194
195 DEBUG(5, ("tdb_validate_open called for tdb '%s'\n", tdb_path));
196
197 tdb = tdb_open_log(tdb_path, 0, TDB_DEFAULT, O_RDWR, 0);
198 if (!tdb) {
199 DEBUG(1, ("Error opening tdb %s\n", tdb_path));
200 return ret;
201 }
202
203 ret = tdb_validate(tdb, validate_fn);
204 tdb_close(tdb);
205 return ret;
206}
207
208/*
209 * tdb backup function and helpers for tdb_validate wrapper with backup
210 * handling.
211 */
212
213/* this structure eliminates the need for a global overall status for
214 * the traverse-copy */
215struct tdb_copy_data {
216 struct tdb_context *dst;
217 bool success;
218};
219
220static int traverse_copy_fn(struct tdb_context *tdb, TDB_DATA key,
221 TDB_DATA dbuf, void *private_data)
222{
223 struct tdb_copy_data *data = (struct tdb_copy_data *)private_data;
224
225 if (tdb_store(data->dst, key, dbuf, TDB_INSERT) != 0) {
226 DEBUG(4, ("Failed to insert into %s: %s\n", tdb_name(data->dst),
227 strerror(errno)));
228 data->success = False;
229 return 1;
230 }
231 return 0;
232}
233
234static int tdb_copy(struct tdb_context *src, struct tdb_context *dst)
235{
236 struct tdb_copy_data data;
237 int count;
238
239 data.dst = dst;
240 data.success = True;
241
242 count = tdb_traverse(src, traverse_copy_fn, (void *)(&data));
243 if ((count < 0) || (data.success == False)) {
244 return -1;
245 }
246 return count;
247}
248
249static int tdb_verify_basic(struct tdb_context *tdb)
250{
251 return tdb_traverse(tdb, NULL, NULL);
252}
253
254/* this backup function is essentially taken from lib/tdb/tools/tdbbackup.tdb
255 */
256static int tdb_backup(TALLOC_CTX *ctx, const char *src_path,
257 const char *dst_path, int hash_size)
258{
259 struct tdb_context *src_tdb = NULL;
260 struct tdb_context *dst_tdb = NULL;
261 char *tmp_path = NULL;
262 struct stat st;
263 int count1, count2;
264 int saved_errno = 0;
265 int ret = -1;
266
267 if (stat(src_path, &st) != 0) {
268 DEBUG(3, ("Could not stat '%s': %s\n", src_path,
269 strerror(errno)));
270 goto done;
271 }
272
273 /* open old tdb RDWR - so we can lock it */
274 src_tdb = tdb_open_log(src_path, 0, TDB_DEFAULT, O_RDWR, 0);
275 if (src_tdb == NULL) {
276 DEBUG(3, ("Failed to open tdb '%s'\n", src_path));
277 goto done;
278 }
279
280 if (tdb_lockall(src_tdb) != 0) {
281 DEBUG(3, ("Failed to lock tdb '%s'\n", src_path));
282 goto done;
283 }
284
285 tmp_path = talloc_asprintf(ctx, "%s%s", dst_path, ".tmp");
286 if (!tmp_path) {
287 DEBUG(3, ("talloc fail\n"));
288 goto done;
289 }
290
291 unlink(tmp_path);
292
293 if (!hash_size) {
294 hash_size = tdb_hash_size(src_tdb);
295 }
296
297 dst_tdb = tdb_open_log(tmp_path, hash_size,
298 TDB_DEFAULT, O_RDWR | O_CREAT | O_EXCL,
299 st.st_mode & 0777);
300 if (dst_tdb == NULL) {
301 DEBUG(3, ("Error creating tdb '%s': %s\n", tmp_path,
302 strerror(errno)));
303 saved_errno = errno;
304 unlink(tmp_path);
305 goto done;
306 }
307
308 count1 = tdb_copy(src_tdb, dst_tdb);
309 if (count1 < 0) {
310 DEBUG(3, ("Failed to copy tdb '%s': %s\n", src_path,
311 strerror(errno)));
312 tdb_close(dst_tdb);
313 goto done;
314 }
315
316 /* reopen ro and do basic verification */
317 tdb_close(dst_tdb);
318 dst_tdb = tdb_open_log(tmp_path, 0, TDB_DEFAULT, O_RDONLY, 0);
319 if (!dst_tdb) {
320 DEBUG(3, ("Failed to reopen tdb '%s': %s\n", tmp_path,
321 strerror(errno)));
322 goto done;
323 }
324 count2 = tdb_verify_basic(dst_tdb);
325 if (count2 != count1) {
326 DEBUG(3, ("Failed to verify result of copying tdb '%s'.\n",
327 src_path));
328 tdb_close(dst_tdb);
329 goto done;
330 }
331
332 DEBUG(10, ("tdb_backup: successfully copied %d entries\n", count1));
333
334 /* make sure the new tdb has reached stable storage
335 * then rename it to its destination */
336 fsync(tdb_fd(dst_tdb));
337 tdb_close(dst_tdb);
338 unlink(dst_path);
339 if (rename(tmp_path, dst_path) != 0) {
340 DEBUG(3, ("Failed to rename '%s' to '%s': %s\n",
341 tmp_path, dst_path, strerror(errno)));
342 goto done;
343 }
344
345 /* success */
346 ret = 0;
347
348done:
349 if (src_tdb != NULL) {
350 tdb_close(src_tdb);
351 }
352 if (tmp_path != NULL) {
353 unlink(tmp_path);
354 TALLOC_FREE(tmp_path);
355 }
356 if (saved_errno != 0) {
357 errno = saved_errno;
358 }
359 return ret;
360}
361
362static int rename_file_with_suffix(TALLOC_CTX *ctx, const char *path,
363 const char *suffix)
364{
365 int ret = -1;
366 char *dst_path;
367
368 dst_path = talloc_asprintf(ctx, "%s%s", path, suffix);
369 if (dst_path == NULL) {
370 DEBUG(3, ("error out of memory\n"));
371 return ret;
372 }
373
374 ret = (rename(path, dst_path) != 0);
375
376 if (ret == 0) {
377 DEBUG(5, ("moved '%s' to '%s'\n", path, dst_path));
378 } else if (errno == ENOENT) {
379 DEBUG(3, ("file '%s' does not exist - so not moved\n", path));
380 ret = 0;
381 } else {
382 DEBUG(3, ("error renaming %s to %s: %s\n", path, dst_path,
383 strerror(errno)));
384 }
385
386 TALLOC_FREE(dst_path);
387 return ret;
388}
389
390/*
391 * do a backup of a tdb, moving the destination out of the way first
392 */
393static int tdb_backup_with_rotate(TALLOC_CTX *ctx, const char *src_path,
394 const char *dst_path, int hash_size,
395 const char *rotate_suffix,
396 bool retry_norotate_if_nospc,
397 bool rename_as_last_resort_if_nospc)
398{
399 int ret;
400
401 rename_file_with_suffix(ctx, dst_path, rotate_suffix);
402
403 ret = tdb_backup(ctx, src_path, dst_path, hash_size);
404
405 if (ret != 0) {
406 DEBUG(10, ("backup of %s failed: %s\n", src_path, strerror(errno)));
407 }
408 if ((ret != 0) && (errno == ENOSPC) && retry_norotate_if_nospc)
409 {
410 char *rotate_path = talloc_asprintf(ctx, "%s%s", dst_path,
411 rotate_suffix);
412 if (rotate_path == NULL) {
413 DEBUG(10, ("talloc fail\n"));
414 return -1;
415 }
416 DEBUG(10, ("backup of %s failed due to lack of space\n",
417 src_path));
418 DEBUGADD(10, ("trying to free some space by removing rotated "
419 "dst %s\n", rotate_path));
420 if (unlink(rotate_path) == -1) {
421 DEBUG(10, ("unlink of %s failed: %s\n", rotate_path,
422 strerror(errno)));
423 } else {
424 ret = tdb_backup(ctx, src_path, dst_path, hash_size);
425 }
426 TALLOC_FREE(rotate_path);
427 }
428
429 if ((ret != 0) && (errno == ENOSPC) && rename_as_last_resort_if_nospc)
430 {
431 DEBUG(10, ("backup of %s failed due to lack of space\n",
432 src_path));
433 DEBUGADD(10, ("using 'rename' as a last resort\n"));
434 ret = rename(src_path, dst_path);
435 }
436
437 return ret;
438}
439
440/*
441 * validation function with backup handling:
442 *
443 * - calls tdb_validate
444 * - if the tdb is ok, create a backup "name.bak", possibly moving
445 * existing backup to name.bak.old,
446 * return 0 (success) even if the backup fails
447 * - if the tdb is corrupt:
448 * - move the tdb to "name.corrupt"
449 * - check if there is valid backup.
450 * if so, restore the backup.
451 * if restore is successful, return 0 (success),
452 * - otherwise return -1 (failure)
453 */
454int tdb_validate_and_backup(const char *tdb_path,
455 tdb_validate_data_func validate_fn)
456{
457 int ret = -1;
458 const char *backup_suffix = ".bak";
459 const char *corrupt_suffix = ".corrupt";
460 const char *rotate_suffix = ".old";
461 char *tdb_path_backup;
462 struct stat st;
463 TALLOC_CTX *ctx = NULL;
464
465 ctx = talloc_new(NULL);
466 if (ctx == NULL) {
467 DEBUG(0, ("tdb_validate_and_backup: out of memory\n"));
468 goto done;
469 }
470
471 tdb_path_backup = talloc_asprintf(ctx, "%s%s", tdb_path, backup_suffix);
472 if (!tdb_path_backup) {
473 DEBUG(0, ("tdb_validate_and_backup: out of memory\n"));
474 goto done;
475 }
476
477 ret = tdb_validate_open(tdb_path, validate_fn);
478
479 if (ret == 0) {
480 DEBUG(1, ("tdb '%s' is valid\n", tdb_path));
481 ret = tdb_backup_with_rotate(ctx, tdb_path, tdb_path_backup, 0,
482 rotate_suffix, True, False);
483 if (ret != 0) {
484 DEBUG(1, ("Error creating backup of tdb '%s'\n",
485 tdb_path));
486 /* the actual validation was successful: */
487 ret = 0;
488 } else {
489 DEBUG(1, ("Created backup '%s' of tdb '%s'\n",
490 tdb_path_backup, tdb_path));
491 }
492 } else {
493 DEBUG(1, ("tdb '%s' is invalid\n", tdb_path));
494
495 ret =stat(tdb_path_backup, &st);
496 if (ret != 0) {
497 DEBUG(5, ("Could not stat '%s': %s\n", tdb_path_backup,
498 strerror(errno)));
499 DEBUG(1, ("No backup found.\n"));
500 } else {
501 DEBUG(1, ("backup '%s' found.\n", tdb_path_backup));
502 ret = tdb_validate_open(tdb_path_backup, validate_fn);
503 if (ret != 0) {
504 DEBUG(1, ("Backup '%s' is invalid.\n",
505 tdb_path_backup));
506 }
507 }
508
509 if (ret != 0) {
510 int renamed = rename_file_with_suffix(ctx, tdb_path,
511 corrupt_suffix);
512 if (renamed != 0) {
513 DEBUG(1, ("Error moving tdb to '%s%s'\n",
514 tdb_path, corrupt_suffix));
515 } else {
516 DEBUG(1, ("Corrupt tdb stored as '%s%s'\n",
517 tdb_path, corrupt_suffix));
518 }
519 goto done;
520 }
521
522 DEBUG(1, ("valid backup '%s' found\n", tdb_path_backup));
523 ret = tdb_backup_with_rotate(ctx, tdb_path_backup, tdb_path, 0,
524 corrupt_suffix, True, True);
525 if (ret != 0) {
526 DEBUG(1, ("Error restoring backup from '%s'\n",
527 tdb_path_backup));
528 } else {
529 DEBUG(1, ("Restored tdb backup from '%s'\n",
530 tdb_path_backup));
531 }
532 }
533
534done:
535 TALLOC_FREE(ctx);
536 return ret;
537}
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