source: vendor/current/lib/tdb/tools/tdbbackup.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: 7.7 KB
Line 
1/*
2 Unix SMB/CIFS implementation.
3 low level tdb backup and restore utility
4 Copyright (C) Andrew Tridgell 2002
5
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
18*/
19
20/*
21
22 This program is meant for backup/restore of tdb databases. Typical usage would be:
23 tdbbackup *.tdb
24 when Samba shuts down cleanly, which will make a backup of all the local databases
25 to *.bak files. Then on Samba startup you would use:
26 tdbbackup -v *.tdb
27 and this will check the databases for corruption and if corruption is detected then
28 the backup will be restored.
29
30 You may also like to do a backup on a regular basis while Samba is
31 running, perhaps using cron.
32
33 The reason this program is needed is to cope with power failures
34 while Samba is running. A power failure could lead to database
35 corruption and Samba will then not start correctly.
36
37 Note that many of the databases in Samba are transient and thus
38 don't need to be backed up, so you can optimise the above a little
39 by only running the backup on the critical databases.
40
41 */
42
43#include "replace.h"
44#include "system/locale.h"
45#include "system/time.h"
46#include "system/filesys.h"
47#include "system/wait.h"
48#include "tdb.h"
49
50#ifdef HAVE_GETOPT_H
51#include <getopt.h>
52#endif
53
54static int failed;
55
56static struct tdb_logging_context log_ctx;
57
58#ifdef PRINTF_ATTRIBUTE
59static void tdb_log(struct tdb_context *tdb, enum tdb_debug_level level, const char *format, ...) PRINTF_ATTRIBUTE(3,4);
60#endif
61static void tdb_log(struct tdb_context *tdb, enum tdb_debug_level level, const char *format, ...)
62{
63 va_list ap;
64
65 va_start(ap, format);
66 vfprintf(stdout, format, ap);
67 va_end(ap);
68 fflush(stdout);
69}
70
71static char *add_suffix(const char *name, const char *suffix)
72{
73 char *ret;
74 int len = strlen(name) + strlen(suffix) + 1;
75 ret = (char *)malloc(len);
76 if (!ret) {
77 fprintf(stderr,"Out of memory!\n");
78 exit(1);
79 }
80 snprintf(ret, len, "%s%s", name, suffix);
81 return ret;
82}
83
84static int copy_fn(TDB_CONTEXT *tdb, TDB_DATA key, TDB_DATA dbuf, void *state)
85{
86 TDB_CONTEXT *tdb_new = (TDB_CONTEXT *)state;
87
88 if (tdb_store(tdb_new, key, dbuf, TDB_INSERT) != 0) {
89 fprintf(stderr,"Failed to insert into %s\n", tdb_name(tdb_new));
90 failed = 1;
91 return 1;
92 }
93 return 0;
94}
95
96
97static int test_fn(TDB_CONTEXT *tdb, TDB_DATA key, TDB_DATA dbuf, void *state)
98{
99 return 0;
100}
101
102/*
103 carefully backup a tdb, validating the contents and
104 only doing the backup if its OK
105 this function is also used for restore
106*/
107static int backup_tdb(const char *old_name, const char *new_name,
108 int hash_size, int nolock)
109{
110 TDB_CONTEXT *tdb;
111 TDB_CONTEXT *tdb_new;
112 char *tmp_name;
113 struct stat st;
114 int count1, count2;
115
116 tmp_name = add_suffix(new_name, ".tmp");
117
118 /* stat the old tdb to find its permissions */
119 if (stat(old_name, &st) != 0) {
120 perror(old_name);
121 free(tmp_name);
122 return 1;
123 }
124
125 /* open the old tdb */
126 tdb = tdb_open_ex(old_name, 0,
127 TDB_DEFAULT | (nolock ? TDB_NOLOCK : 0),
128 O_RDWR, 0, &log_ctx, NULL);
129 if (!tdb) {
130 printf("Failed to open %s\n", old_name);
131 free(tmp_name);
132 return 1;
133 }
134
135 /* create the new tdb */
136 unlink(tmp_name);
137 tdb_new = tdb_open_ex(tmp_name,
138 hash_size ? hash_size : tdb_hash_size(tdb),
139 TDB_DEFAULT,
140 O_RDWR|O_CREAT|O_EXCL, st.st_mode & 0777,
141 &log_ctx, NULL);
142 if (!tdb_new) {
143 perror(tmp_name);
144 free(tmp_name);
145 return 1;
146 }
147
148 if (tdb_transaction_start(tdb) != 0) {
149 printf("Failed to start transaction on old tdb\n");
150 tdb_close(tdb);
151 tdb_close(tdb_new);
152 unlink(tmp_name);
153 free(tmp_name);
154 return 1;
155 }
156
157 /* lock the backup tdb so that nobody else can change it */
158 if (tdb_lockall(tdb_new) != 0) {
159 printf("Failed to lock backup tdb\n");
160 tdb_close(tdb);
161 tdb_close(tdb_new);
162 unlink(tmp_name);
163 free(tmp_name);
164 return 1;
165 }
166
167 failed = 0;
168
169 /* traverse and copy */
170 count1 = tdb_traverse(tdb, copy_fn, (void *)tdb_new);
171 if (count1 < 0 || failed) {
172 fprintf(stderr,"failed to copy %s\n", old_name);
173 tdb_close(tdb);
174 tdb_close(tdb_new);
175 unlink(tmp_name);
176 free(tmp_name);
177 return 1;
178 }
179
180 /* close the old tdb */
181 tdb_close(tdb);
182
183 /* copy done, unlock the backup tdb */
184 tdb_unlockall(tdb_new);
185
186#ifdef HAVE_FDATASYNC
187 if (fdatasync(tdb_fd(tdb_new)) != 0) {
188#else
189 if (fsync(tdb_fd(tdb_new)) != 0) {
190#endif
191 /* not fatal */
192 fprintf(stderr, "failed to fsync backup file\n");
193 }
194
195 /* close the new tdb and re-open read-only */
196 tdb_close(tdb_new);
197 tdb_new = tdb_open_ex(tmp_name,
198 0,
199 TDB_DEFAULT,
200 O_RDONLY, 0,
201 &log_ctx, NULL);
202 if (!tdb_new) {
203 fprintf(stderr,"failed to reopen %s\n", tmp_name);
204 unlink(tmp_name);
205 perror(tmp_name);
206 free(tmp_name);
207 return 1;
208 }
209
210 /* traverse the new tdb to confirm */
211 count2 = tdb_traverse(tdb_new, test_fn, NULL);
212 if (count2 != count1) {
213 fprintf(stderr,"failed to copy %s\n", old_name);
214 tdb_close(tdb_new);
215 unlink(tmp_name);
216 free(tmp_name);
217 return 1;
218 }
219
220 /* close the new tdb and rename it to .bak */
221 tdb_close(tdb_new);
222 if (rename(tmp_name, new_name) != 0) {
223 perror(new_name);
224 free(tmp_name);
225 return 1;
226 }
227
228 free(tmp_name);
229
230 return 0;
231}
232
233/*
234 verify a tdb and if it is corrupt then restore from *.bak
235*/
236static int verify_tdb(const char *fname, const char *bak_name)
237{
238 TDB_CONTEXT *tdb;
239 int count = -1;
240
241 /* open the tdb */
242 tdb = tdb_open_ex(fname, 0, 0,
243 O_RDONLY, 0, &log_ctx, NULL);
244
245 /* traverse the tdb, then close it */
246 if (tdb) {
247 count = tdb_traverse(tdb, test_fn, NULL);
248 tdb_close(tdb);
249 }
250
251 /* count is < 0 means an error */
252 if (count < 0) {
253 printf("restoring %s\n", fname);
254 return backup_tdb(bak_name, fname, 0, 0);
255 }
256
257 printf("%s : %d records\n", fname, count);
258
259 return 0;
260}
261
262/*
263 see if one file is newer than another
264*/
265static int file_newer(const char *fname1, const char *fname2)
266{
267 struct stat st1, st2;
268 if (stat(fname1, &st1) != 0) {
269 return 0;
270 }
271 if (stat(fname2, &st2) != 0) {
272 return 1;
273 }
274 return (st1.st_mtime > st2.st_mtime);
275}
276
277static void usage(void)
278{
279 printf("Usage: tdbbackup [options] <fname...>\n\n");
280 printf(" -h this help message\n");
281 printf(" -s suffix set the backup suffix\n");
282 printf(" -v verify mode (restore if corrupt)\n");
283 printf(" -n hashsize set the new hash size for the backup\n");
284 printf(" -l open without locking to back up mutex dbs\n");
285}
286
287 int main(int argc, char *argv[])
288{
289 int i;
290 int ret = 0;
291 int c;
292 int verify = 0;
293 int hashsize = 0;
294 int nolock = 0;
295 const char *suffix = ".bak";
296
297 log_ctx.log_fn = tdb_log;
298
299 while ((c = getopt(argc, argv, "vhs:n:l")) != -1) {
300 switch (c) {
301 case 'h':
302 usage();
303 exit(0);
304 case 'v':
305 verify = 1;
306 break;
307 case 's':
308 suffix = optarg;
309 break;
310 case 'n':
311 hashsize = atoi(optarg);
312 break;
313 case 'l':
314 nolock = 1;
315 break;
316 }
317 }
318
319 argc -= optind;
320 argv += optind;
321
322 if (argc < 1) {
323 usage();
324 exit(1);
325 }
326
327 for (i=0; i<argc; i++) {
328 const char *fname = argv[i];
329 char *bak_name;
330
331 bak_name = add_suffix(fname, suffix);
332
333 if (verify) {
334 if (verify_tdb(fname, bak_name) != 0) {
335 ret = 1;
336 }
337 } else {
338 if (file_newer(fname, bak_name) &&
339 backup_tdb(fname, bak_name, hashsize,
340 nolock) != 0) {
341 ret = 1;
342 }
343 }
344
345 free(bak_name);
346 }
347
348 return ret;
349}
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