Line data Source code
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 : */
30 13 : static int tdb_validate_child(struct tdb_context *tdb,
31 : tdb_validate_data_func validate_fn)
32 : {
33 13 : int ret = 1;
34 1 : int check_rc;
35 13 : int num_entries = 0;
36 1 : struct tdb_validation_status v_status;
37 :
38 13 : v_status.tdb_error = False;
39 13 : v_status.bad_freelist = False;
40 13 : v_status.bad_entry = False;
41 13 : v_status.unknown_key = False;
42 13 : v_status.success = True;
43 :
44 13 : if (!tdb) {
45 0 : v_status.tdb_error = True;
46 0 : v_status.success = False;
47 0 : goto out;
48 : }
49 :
50 : /*
51 : * we can simplify this by passing a check function,
52 : * but I don't want to change all the callers...
53 : */
54 13 : check_rc = tdb_check(tdb, NULL, NULL);
55 13 : if (check_rc != 0) {
56 0 : v_status.tdb_error = True;
57 0 : v_status.success = False;
58 0 : goto out;
59 : }
60 :
61 : /* Check if the tdb's freelist is good. */
62 13 : if (tdb_validate_freelist(tdb, &num_entries) == -1) {
63 0 : v_status.bad_freelist = True;
64 0 : v_status.success = False;
65 0 : goto out;
66 : }
67 :
68 13 : DEBUG(10,("tdb_validate_child: tdb %s freelist has %d entries\n",
69 : tdb_name(tdb), num_entries));
70 :
71 : /* Now traverse the tdb to validate it. */
72 13 : num_entries = tdb_traverse(tdb, validate_fn, (void *)&v_status);
73 13 : if (!v_status.success) {
74 1 : goto out;
75 12 : } else if (num_entries < 0) {
76 0 : v_status.tdb_error = True;
77 0 : v_status.success = False;
78 0 : goto out;
79 : }
80 :
81 12 : DEBUG(10,("tdb_validate_child: tdb %s is good with %d entries\n",
82 : tdb_name(tdb), num_entries));
83 12 : ret = 0; /* Cache is good. */
84 :
85 13 : out:
86 13 : DEBUG(10, ("tdb_validate_child: summary of validation status:\n"));
87 13 : DEBUGADD(10,(" * tdb error: %s\n", v_status.tdb_error ? "yes" : "no"));
88 13 : DEBUGADD(10,(" * bad freelist: %s\n",v_status.bad_freelist?"yes":"no"));
89 13 : DEBUGADD(10,(" * bad entry: %s\n", v_status.bad_entry ? "yes" : "no"));
90 13 : DEBUGADD(10,(" * unknown key: %s\n", v_status.unknown_key?"yes":"no"));
91 13 : DEBUGADD(10,(" => overall success: %s\n", v_status.success?"yes":"no"));
92 :
93 13 : return ret;
94 : }
95 :
96 : /*
97 : * tdb validation function.
98 : * returns 0 if tdb is ok, != 0 if it isn't.
99 : * this function expects an opened tdb.
100 : */
101 9 : int tdb_validate(struct tdb_context *tdb, tdb_validate_data_func validate_fn)
102 : {
103 9 : pid_t child_pid = -1;
104 9 : int child_status = 0;
105 9 : int wait_pid = 0;
106 9 : int ret = 1;
107 :
108 9 : if (tdb == NULL) {
109 0 : DEBUG(1, ("Error: tdb_validate called with tdb == NULL\n"));
110 0 : return ret;
111 : }
112 :
113 9 : DEBUG(5, ("tdb_validate called for tdb '%s'\n", tdb_name(tdb)));
114 :
115 : /* fork and let the child do the validation.
116 : * benefit: no need to twist signal handlers and panic functions.
117 : * just let the child panic. we catch the signal. */
118 :
119 9 : DEBUG(10, ("tdb_validate: forking to let child do validation.\n"));
120 9 : child_pid = fork();
121 22 : if (child_pid == 0) {
122 : /* child code */
123 13 : DEBUG(10, ("tdb_validate (validation child): created\n"));
124 13 : DEBUG(10, ("tdb_validate (validation child): "
125 : "calling tdb_validate_child\n"));
126 13 : exit(tdb_validate_child(tdb, validate_fn));
127 : }
128 9 : else if (child_pid < 0) {
129 0 : DEBUG(1, ("tdb_validate: fork for validation failed.\n"));
130 0 : goto done;
131 : }
132 :
133 : /* parent */
134 :
135 9 : DEBUG(10, ("tdb_validate: fork succeeded, child PID = %u\n",
136 : (unsigned int)child_pid));
137 :
138 9 : DEBUG(10, ("tdb_validate: waiting for child to finish...\n"));
139 9 : while ((wait_pid = waitpid(child_pid, &child_status, 0)) < 0) {
140 0 : if (errno == EINTR) {
141 0 : DEBUG(10, ("tdb_validate: got signal during waitpid, "
142 : "retrying\n"));
143 0 : errno = 0;
144 0 : continue;
145 : }
146 0 : DEBUG(1, ("tdb_validate: waitpid failed with error '%s'.\n",
147 : strerror(errno)));
148 0 : goto done;
149 : }
150 9 : if (wait_pid != child_pid) {
151 0 : DEBUG(1, ("tdb_validate: waitpid returned pid %d, "
152 : "but %u was expected\n", wait_pid, (unsigned int)child_pid));
153 0 : goto done;
154 : }
155 :
156 9 : DEBUG(10, ("tdb_validate: validating child returned.\n"));
157 9 : if (WIFEXITED(child_status)) {
158 9 : DEBUG(10, ("tdb_validate: child exited, code %d.\n",
159 : WEXITSTATUS(child_status)));
160 9 : ret = WEXITSTATUS(child_status);
161 : }
162 9 : if (WIFSIGNALED(child_status)) {
163 0 : DEBUG(10, ("tdb_validate: child terminated by signal %d\n",
164 : WTERMSIG(child_status)));
165 : #ifdef WCOREDUMP
166 0 : if (WCOREDUMP(child_status)) {
167 0 : DEBUGADD(10, ("core dumped\n"));
168 : }
169 : #endif
170 0 : ret = WTERMSIG(child_status);
171 : }
172 9 : if (WIFSTOPPED(child_status)) {
173 0 : DEBUG(10, ("tdb_validate: child was stopped by signal %d\n",
174 : WSTOPSIG(child_status)));
175 0 : ret = WSTOPSIG(child_status);
176 : }
177 :
178 9 : done:
179 9 : DEBUG(5, ("tdb_validate returning code '%d' for tdb '%s'\n", ret,
180 : tdb_name(tdb)));
181 :
182 8 : return ret;
183 : }
184 :
185 : /*
186 : * tdb validation function.
187 : * returns 0 if tdb is ok, != 0 if it isn't.
188 : * this is a wrapper around the actual validation function that opens and closes
189 : * the tdb.
190 : */
191 8 : int tdb_validate_open(const char *tdb_path, tdb_validate_data_func validate_fn)
192 : {
193 8 : TDB_CONTEXT *tdb = NULL;
194 8 : int ret = 1;
195 :
196 8 : DEBUG(5, ("tdb_validate_open called for tdb '%s'\n", tdb_path));
197 :
198 8 : tdb = tdb_open_log(tdb_path, 0, TDB_DEFAULT, O_RDWR, 0);
199 8 : if (!tdb) {
200 0 : DEBUG(1, ("Error opening tdb %s\n", tdb_path));
201 0 : return ret;
202 : }
203 :
204 8 : ret = tdb_validate(tdb, validate_fn);
205 8 : tdb_close(tdb);
206 8 : return ret;
207 : }
208 :
209 : /*
210 : * tdb backup function and helpers for tdb_validate wrapper with backup
211 : * handling.
212 : */
213 :
214 : /* this structure eliminates the need for a global overall status for
215 : * the traverse-copy */
216 : struct tdb_copy_data {
217 : struct tdb_context *dst;
218 : bool success;
219 : };
220 :
221 32 : static int traverse_copy_fn(struct tdb_context *tdb, TDB_DATA key,
222 : TDB_DATA dbuf, void *private_data)
223 : {
224 32 : struct tdb_copy_data *data = (struct tdb_copy_data *)private_data;
225 :
226 32 : if (tdb_store(data->dst, key, dbuf, TDB_INSERT) != 0) {
227 0 : DEBUG(4, ("Failed to insert into %s: %s\n", tdb_name(data->dst),
228 : strerror(errno)));
229 0 : data->success = False;
230 0 : return 1;
231 : }
232 32 : return 0;
233 : }
234 :
235 8 : static int tdb_copy(struct tdb_context *src, struct tdb_context *dst)
236 : {
237 0 : struct tdb_copy_data data;
238 0 : int count;
239 :
240 8 : data.dst = dst;
241 8 : data.success = True;
242 :
243 8 : count = tdb_traverse(src, traverse_copy_fn, (void *)(&data));
244 8 : if ((count < 0) || (data.success == False)) {
245 0 : return -1;
246 : }
247 8 : return count;
248 : }
249 :
250 8 : static int tdb_verify_basic(struct tdb_context *tdb)
251 : {
252 8 : return tdb_traverse(tdb, NULL, NULL);
253 : }
254 :
255 : /* this backup function is essentially taken from lib/tdb/tools/tdbbackup.tdb
256 : */
257 8 : static int tdb_backup(TALLOC_CTX *ctx, const char *src_path,
258 : const char *dst_path, int hash_size)
259 : {
260 8 : struct tdb_context *src_tdb = NULL;
261 8 : struct tdb_context *dst_tdb = NULL;
262 8 : char *tmp_path = NULL;
263 0 : struct stat st;
264 0 : int count1, count2;
265 8 : int saved_errno = 0;
266 8 : int ret = -1;
267 :
268 8 : if (stat(src_path, &st) != 0) {
269 0 : DEBUG(3, ("Could not stat '%s': %s\n", src_path,
270 : strerror(errno)));
271 0 : goto done;
272 : }
273 :
274 : /* open old tdb RDWR - so we can lock it */
275 8 : src_tdb = tdb_open_log(src_path, 0, TDB_DEFAULT, O_RDWR, 0);
276 8 : if (src_tdb == NULL) {
277 0 : DEBUG(3, ("Failed to open tdb '%s'\n", src_path));
278 0 : goto done;
279 : }
280 :
281 8 : if (tdb_lockall(src_tdb) != 0) {
282 0 : DEBUG(3, ("Failed to lock tdb '%s'\n", src_path));
283 0 : goto done;
284 : }
285 :
286 8 : tmp_path = talloc_asprintf(ctx, "%s%s", dst_path, ".tmp");
287 8 : if (!tmp_path) {
288 0 : DEBUG(3, ("talloc fail\n"));
289 0 : goto done;
290 : }
291 :
292 8 : unlink(tmp_path);
293 :
294 8 : if (!hash_size) {
295 8 : hash_size = tdb_hash_size(src_tdb);
296 : }
297 :
298 8 : dst_tdb = tdb_open_log(tmp_path, hash_size,
299 : TDB_DEFAULT, O_RDWR | O_CREAT | O_EXCL,
300 8 : st.st_mode & 0777);
301 8 : if (dst_tdb == NULL) {
302 0 : DEBUG(3, ("Error creating tdb '%s': %s\n", tmp_path,
303 : strerror(errno)));
304 0 : saved_errno = errno;
305 0 : unlink(tmp_path);
306 0 : goto done;
307 : }
308 :
309 8 : count1 = tdb_copy(src_tdb, dst_tdb);
310 8 : if (count1 < 0) {
311 0 : DEBUG(3, ("Failed to copy tdb '%s': %s\n", src_path,
312 : strerror(errno)));
313 0 : tdb_close(dst_tdb);
314 0 : goto done;
315 : }
316 :
317 : /* reopen ro and do basic verification */
318 8 : tdb_close(dst_tdb);
319 8 : dst_tdb = tdb_open_log(tmp_path, 0, TDB_DEFAULT, O_RDONLY, 0);
320 8 : if (!dst_tdb) {
321 0 : DEBUG(3, ("Failed to reopen tdb '%s': %s\n", tmp_path,
322 : strerror(errno)));
323 0 : goto done;
324 : }
325 8 : count2 = tdb_verify_basic(dst_tdb);
326 8 : if (count2 != count1) {
327 0 : DEBUG(3, ("Failed to verify result of copying tdb '%s'.\n",
328 : src_path));
329 0 : tdb_close(dst_tdb);
330 0 : goto done;
331 : }
332 :
333 8 : DEBUG(10, ("tdb_backup: successfully copied %d entries\n", count1));
334 :
335 : /* make sure the new tdb has reached stable storage
336 : * then rename it to its destination */
337 8 : fsync(tdb_fd(dst_tdb));
338 8 : tdb_close(dst_tdb);
339 8 : unlink(dst_path);
340 8 : if (rename(tmp_path, dst_path) != 0) {
341 0 : DEBUG(3, ("Failed to rename '%s' to '%s': %s\n",
342 : tmp_path, dst_path, strerror(errno)));
343 0 : goto done;
344 : }
345 :
346 : /* success */
347 8 : ret = 0;
348 :
349 8 : done:
350 8 : if (src_tdb != NULL) {
351 8 : tdb_close(src_tdb);
352 : }
353 8 : if (tmp_path != NULL) {
354 8 : unlink(tmp_path);
355 8 : TALLOC_FREE(tmp_path);
356 : }
357 8 : if (saved_errno != 0) {
358 0 : errno = saved_errno;
359 : }
360 8 : return ret;
361 : }
362 :
363 8 : static int rename_file_with_suffix(TALLOC_CTX *ctx, const char *path,
364 : const char *suffix)
365 : {
366 8 : int ret = -1;
367 0 : char *dst_path;
368 :
369 8 : dst_path = talloc_asprintf(ctx, "%s%s", path, suffix);
370 8 : if (dst_path == NULL) {
371 0 : DEBUG(3, ("error out of memory\n"));
372 0 : return ret;
373 : }
374 :
375 8 : ret = (rename(path, dst_path) != 0);
376 :
377 8 : if (ret == 0) {
378 4 : DEBUG(5, ("moved '%s' to '%s'\n", path, dst_path));
379 4 : } else if (errno == ENOENT) {
380 4 : DEBUG(3, ("file '%s' does not exist - so not moved\n", path));
381 4 : ret = 0;
382 : } else {
383 0 : DEBUG(3, ("error renaming %s to %s: %s\n", path, dst_path,
384 : strerror(errno)));
385 : }
386 :
387 8 : TALLOC_FREE(dst_path);
388 8 : return ret;
389 : }
390 :
391 : /*
392 : * do a backup of a tdb, moving the destination out of the way first
393 : */
394 8 : static int tdb_backup_with_rotate(TALLOC_CTX *ctx, const char *src_path,
395 : const char *dst_path, int hash_size,
396 : const char *rotate_suffix,
397 : bool retry_norotate_if_nospc,
398 : bool rename_as_last_resort_if_nospc)
399 : {
400 0 : int ret;
401 :
402 8 : rename_file_with_suffix(ctx, dst_path, rotate_suffix);
403 :
404 8 : ret = tdb_backup(ctx, src_path, dst_path, hash_size);
405 :
406 8 : if (ret != 0) {
407 0 : DEBUG(10, ("backup of %s failed: %s\n", src_path, strerror(errno)));
408 : }
409 8 : if ((ret != 0) && (errno == ENOSPC) && retry_norotate_if_nospc)
410 : {
411 0 : char *rotate_path = talloc_asprintf(ctx, "%s%s", dst_path,
412 : rotate_suffix);
413 0 : if (rotate_path == NULL) {
414 0 : DEBUG(10, ("talloc fail\n"));
415 0 : return -1;
416 : }
417 0 : DEBUG(10, ("backup of %s failed due to lack of space\n",
418 : src_path));
419 0 : DEBUGADD(10, ("trying to free some space by removing rotated "
420 : "dst %s\n", rotate_path));
421 0 : if (unlink(rotate_path) == -1) {
422 0 : DEBUG(10, ("unlink of %s failed: %s\n", rotate_path,
423 : strerror(errno)));
424 : } else {
425 0 : ret = tdb_backup(ctx, src_path, dst_path, hash_size);
426 : }
427 0 : TALLOC_FREE(rotate_path);
428 : }
429 :
430 8 : if ((ret != 0) && (errno == ENOSPC) && rename_as_last_resort_if_nospc)
431 : {
432 0 : DEBUG(10, ("backup of %s failed due to lack of space\n",
433 : src_path));
434 0 : DEBUGADD(10, ("using 'rename' as a last resort\n"));
435 0 : ret = rename(src_path, dst_path);
436 : }
437 :
438 8 : return ret;
439 : }
440 :
441 : /*
442 : * validation function with backup handling:
443 : *
444 : * - calls tdb_validate
445 : * - if the tdb is ok, create a backup "name.bak", possibly moving
446 : * existing backup to name.bak.old,
447 : * return 0 (success) even if the backup fails
448 : * - if the tdb is corrupt:
449 : * - move the tdb to "name.corrupt"
450 : * - check if there is valid backup.
451 : * if so, restore the backup.
452 : * if restore is successful, return 0 (success),
453 : * - otherwise return -1 (failure)
454 : */
455 8 : int tdb_validate_and_backup(const char *tdb_path,
456 : tdb_validate_data_func validate_fn)
457 : {
458 8 : int ret = -1;
459 8 : const char *backup_suffix = ".bak";
460 8 : const char *corrupt_suffix = ".corrupt";
461 8 : const char *rotate_suffix = ".old";
462 0 : char *tdb_path_backup;
463 0 : struct stat st;
464 8 : TALLOC_CTX *ctx = NULL;
465 :
466 8 : ctx = talloc_new(NULL);
467 8 : if (ctx == NULL) {
468 0 : DEBUG(0, ("tdb_validate_and_backup: out of memory\n"));
469 0 : goto done;
470 : }
471 :
472 8 : tdb_path_backup = talloc_asprintf(ctx, "%s%s", tdb_path, backup_suffix);
473 8 : if (!tdb_path_backup) {
474 0 : DEBUG(0, ("tdb_validate_and_backup: out of memory\n"));
475 0 : goto done;
476 : }
477 :
478 8 : ret = tdb_validate_open(tdb_path, validate_fn);
479 :
480 8 : if (ret == 0) {
481 8 : DEBUG(1, ("tdb '%s' is valid\n", tdb_path));
482 8 : ret = tdb_backup_with_rotate(ctx, tdb_path, tdb_path_backup, 0,
483 : rotate_suffix, True, False);
484 8 : if (ret != 0) {
485 0 : DEBUG(1, ("Error creating backup of tdb '%s'\n",
486 : tdb_path));
487 : /* the actual validation was successful: */
488 0 : ret = 0;
489 : } else {
490 8 : DEBUG(1, ("Created backup '%s' of tdb '%s'\n",
491 : tdb_path_backup, tdb_path));
492 : }
493 : } else {
494 0 : DEBUG(1, ("tdb '%s' is invalid\n", tdb_path));
495 :
496 0 : ret =stat(tdb_path_backup, &st);
497 0 : if (ret != 0) {
498 0 : DEBUG(5, ("Could not stat '%s': %s\n", tdb_path_backup,
499 : strerror(errno)));
500 0 : DEBUG(1, ("No backup found.\n"));
501 : } else {
502 0 : DEBUG(1, ("backup '%s' found.\n", tdb_path_backup));
503 0 : ret = tdb_validate_open(tdb_path_backup, validate_fn);
504 0 : if (ret != 0) {
505 0 : DEBUG(1, ("Backup '%s' is invalid.\n",
506 : tdb_path_backup));
507 : }
508 : }
509 :
510 0 : if (ret != 0) {
511 0 : int renamed = rename_file_with_suffix(ctx, tdb_path,
512 : corrupt_suffix);
513 0 : if (renamed != 0) {
514 0 : DEBUG(1, ("Error moving tdb to '%s%s'\n",
515 : tdb_path, corrupt_suffix));
516 : } else {
517 0 : DEBUG(1, ("Corrupt tdb stored as '%s%s'\n",
518 : tdb_path, corrupt_suffix));
519 : }
520 0 : goto done;
521 : }
522 :
523 0 : DEBUG(1, ("valid backup '%s' found\n", tdb_path_backup));
524 0 : ret = tdb_backup_with_rotate(ctx, tdb_path_backup, tdb_path, 0,
525 : corrupt_suffix, True, True);
526 0 : if (ret != 0) {
527 0 : DEBUG(1, ("Error restoring backup from '%s'\n",
528 : tdb_path_backup));
529 : } else {
530 0 : DEBUG(1, ("Restored tdb backup from '%s'\n",
531 : tdb_path_backup));
532 : }
533 : }
534 :
535 8 : done:
536 8 : TALLOC_FREE(ctx);
537 8 : return ret;
538 : }
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