source: branches/samba-3.2.x/source/lib/tdb/tools/tdbbackup.c

Last change on this file was 133, checked in by Paul Smedley, 17 years ago

Update trunk to 3.2.0pre3
File size: 6.5 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 char *add_suffix(const char *name, const char *suffix)
57{
58 char *ret;
59 int len = strlen(name) + strlen(suffix) + 1;
60 ret = (char *)malloc(len);
61 if (!ret) {
62 fprintf(stderr,"Out of memory!\n");
63 exit(1);
64 }
65 snprintf(ret, len, "%s%s", name, suffix);
66 return ret;
67}
68
69static int copy_fn(TDB_CONTEXT *tdb, TDB_DATA key, TDB_DATA dbuf, void *state)
70{
71 TDB_CONTEXT *tdb_new = (TDB_CONTEXT *)state;
72
73 if (tdb_store(tdb_new, key, dbuf, TDB_INSERT) != 0) {
74 fprintf(stderr,"Failed to insert into %s\n", tdb_name(tdb_new));
75 failed = 1;
76 return 1;
77 }
78 return 0;
79}
80
81
82static int test_fn(TDB_CONTEXT *tdb, TDB_DATA key, TDB_DATA dbuf, void *state)
83{
84 return 0;
85}
86
87/*
88 carefully backup a tdb, validating the contents and
89 only doing the backup if its OK
90 this function is also used for restore
91*/
92static int backup_tdb(const char *old_name, const char *new_name, int hash_size)
93{
94 TDB_CONTEXT *tdb;
95 TDB_CONTEXT *tdb_new;
96 char *tmp_name;
97 struct stat st;
98 int count1, count2;
99
100 tmp_name = add_suffix(new_name, ".tmp");
101
102 /* stat the old tdb to find its permissions */
103 if (stat(old_name, &st) != 0) {
104 perror(old_name);
105 free(tmp_name);
106 return 1;
107 }
108
109 /* open the old tdb */
110 tdb = tdb_open(old_name, 0, 0, O_RDWR, 0);
111 if (!tdb) {
112 printf("Failed to open %s\n", old_name);
113 free(tmp_name);
114 return 1;
115 }
116
117 /* create the new tdb */
118 unlink(tmp_name);
119 tdb_new = tdb_open(tmp_name,
120 hash_size ? hash_size : tdb_hash_size(tdb),
121 TDB_DEFAULT, O_RDWR|O_CREAT|O_EXCL,
122 st.st_mode & 0777);
123 if (!tdb_new) {
124 perror(tmp_name);
125 free(tmp_name);
126 return 1;
127 }
128
129 /* lock the old tdb */
130 if (tdb_lockall(tdb) != 0) {
131 fprintf(stderr,"Failed to lock %s\n", old_name);
132 tdb_close(tdb);
133 tdb_close(tdb_new);
134 unlink(tmp_name);
135 free(tmp_name);
136 return 1;
137 }
138
139 failed = 0;
140
141 /* traverse and copy */
142 count1 = tdb_traverse(tdb, copy_fn, (void *)tdb_new);
143 if (count1 < 0 || failed) {
144 fprintf(stderr,"failed to copy %s\n", old_name);
145 tdb_close(tdb);
146 tdb_close(tdb_new);
147 unlink(tmp_name);
148 free(tmp_name);
149 return 1;
150 }
151
152 /* close the old tdb */
153 tdb_close(tdb);
154
155 /* close the new tdb and re-open read-only */
156 tdb_close(tdb_new);
157 tdb_new = tdb_open(tmp_name, 0, TDB_DEFAULT, O_RDONLY, 0);
158 if (!tdb_new) {
159 fprintf(stderr,"failed to reopen %s\n", tmp_name);
160 unlink(tmp_name);
161 perror(tmp_name);
162 free(tmp_name);
163 return 1;
164 }
165
166 /* traverse the new tdb to confirm */
167 count2 = tdb_traverse(tdb_new, test_fn, NULL);
168 if (count2 != count1) {
169 fprintf(stderr,"failed to copy %s\n", old_name);
170 tdb_close(tdb_new);
171 unlink(tmp_name);
172 free(tmp_name);
173 return 1;
174 }
175
176 /* make sure the new tdb has reached stable storage */
177 fsync(tdb_fd(tdb_new));
178
179 /* close the new tdb and rename it to .bak */
180 tdb_close(tdb_new);
181 if (rename(tmp_name, new_name) != 0) {
182 perror(new_name);
183 free(tmp_name);
184 return 1;
185 }
186
187 free(tmp_name);
188
189 return 0;
190}
191
192/*
193 verify a tdb and if it is corrupt then restore from *.bak
194*/
195static int verify_tdb(const char *fname, const char *bak_name)
196{
197 TDB_CONTEXT *tdb;
198 int count = -1;
199
200 /* open the tdb */
201 tdb = tdb_open(fname, 0, 0, O_RDONLY, 0);
202
203 /* traverse the tdb, then close it */
204 if (tdb) {
205 count = tdb_traverse(tdb, test_fn, NULL);
206 tdb_close(tdb);
207 }
208
209 /* count is < 0 means an error */
210 if (count < 0) {
211 printf("restoring %s\n", fname);
212 return backup_tdb(bak_name, fname, 0);
213 }
214
215 printf("%s : %d records\n", fname, count);
216
217 return 0;
218}
219
220/*
221 see if one file is newer than another
222*/
223static int file_newer(const char *fname1, const char *fname2)
224{
225 struct stat st1, st2;
226 if (stat(fname1, &st1) != 0) {
227 return 0;
228 }
229 if (stat(fname2, &st2) != 0) {
230 return 1;
231 }
232 return (st1.st_mtime > st2.st_mtime);
233}
234
235static void usage(void)
236{
237 printf("Usage: tdbbackup [options] <fname...>\n\n");
238 printf(" -h this help message\n");
239 printf(" -s suffix set the backup suffix\n");
240 printf(" -v verify mode (restore if corrupt)\n");
241 printf(" -n hashsize set the new hash size for the backup\n");
242}
243
244
245 int main(int argc, char *argv[])
246{
247 int i;
248 int ret = 0;
249 int c;
250 int verify = 0;
251 int hashsize = 0;
252 const char *suffix = ".bak";
253
254 while ((c = getopt(argc, argv, "vhs:n:")) != -1) {
255 switch (c) {
256 case 'h':
257 usage();
258 exit(0);
259 case 'v':
260 verify = 1;
261 break;
262 case 's':
263 suffix = optarg;
264 break;
265 case 'n':
266 hashsize = atoi(optarg);
267 break;
268 }
269 }
270
271 argc -= optind;
272 argv += optind;
273
274 if (argc < 1) {
275 usage();
276 exit(1);
277 }
278
279 for (i=0; i<argc; i++) {
280 const char *fname = argv[i];
281 char *bak_name;
282
283 bak_name = add_suffix(fname, suffix);
284
285 if (verify) {
286 if (verify_tdb(fname, bak_name) != 0) {
287 ret = 1;
288 }
289 } else {
290 if (file_newer(fname, bak_name) &&
291 backup_tdb(fname, bak_name, hashsize) != 0) {
292 ret = 1;
293 }
294 }
295
296 free(bak_name);
297 }
298
299 return ret;
300}
Note: See TracBrowser for help on using the repository browser.