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Diffstat (limited to 'source4/tdb/tdbbackup.c')
| -rw-r--r-- | source4/tdb/tdbbackup.c | 315 |
1 files changed, 315 insertions, 0 deletions
diff --git a/source4/tdb/tdbbackup.c b/source4/tdb/tdbbackup.c new file mode 100644 index 0000000000..7b344de6c4 --- /dev/null +++ b/source4/tdb/tdbbackup.c @@ -0,0 +1,315 @@ +/* + Unix SMB/CIFS implementation. + low level tdb backup and restore utility + Copyright (C) Andrew Tridgell 2002 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +*/ + +/* + + This program is meant for backup/restore of tdb databases. Typical usage would be: + tdbbackup *.tdb + when Samba shuts down cleanly, which will make a backup of all the local databases + to *.bak files. Then on Samba startup you would use: + tdbbackup -v *.tdb + and this will check the databases for corruption and if corruption is detected then + the backup will be restored. + + You may also like to do a backup on a regular basis while Samba is + running, perhaps using cron. + + The reason this program is needed is to cope with power failures + while Samba is running. A power failure could lead to database + corruption and Samba will then not start correctly. + + Note that many of the databases in Samba are transient and thus + don't need to be backed up, so you can optimise the above a little + by only running the backup on the critical databases. + + */ + +#include <errno.h> +#include <stdlib.h> +#include <stdio.h> +#include <fcntl.h> +#include <unistd.h> +#include <string.h> +#include <fcntl.h> +#include <time.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <sys/time.h> +#include <ctype.h> +#include <signal.h> +#include "tdb.h" + +static int failed; + +static char *add_suffix(const char *name, const char *suffix) +{ + char *ret; + int len = strlen(name) + strlen(suffix) + 1; + ret = malloc(len); + if (!ret) { + fprintf(stderr,"Out of memory!\n"); + exit(1); + } + strncpy(ret, name, len); + strncat(ret, suffix, len); + return ret; +} + +static int copy_fn(TDB_CONTEXT *tdb, TDB_DATA key, TDB_DATA dbuf, void *state) +{ + TDB_CONTEXT *tdb_new = (TDB_CONTEXT *)state; + + if (tdb_store(tdb_new, key, dbuf, TDB_INSERT) != 0) { + fprintf(stderr,"Failed to insert into %s\n", tdb_new->name); + failed = 1; + return 1; + } + return 0; +} + + +static int test_fn(TDB_CONTEXT *tdb, TDB_DATA key, TDB_DATA dbuf, void *state) +{ + return 0; +} + +/* + carefully backup a tdb, validating the contents and + only doing the backup if its OK + this function is also used for restore +*/ +static int backup_tdb(const char *old_name, const char *new_name) +{ + TDB_CONTEXT *tdb; + TDB_CONTEXT *tdb_new; + char *tmp_name; + struct stat st; + int count1, count2; + + tmp_name = add_suffix(new_name, ".tmp"); + + /* stat the old tdb to find its permissions */ + if (stat(old_name, &st) != 0) { + perror(old_name); + return 1; + } + + /* open the old tdb */ + tdb = tdb_open(old_name, 0, 0, O_RDWR, 0); + if (!tdb) { + printf("Failed to open %s\n", old_name); + return 1; + } + + /* create the new tdb */ + unlink(tmp_name); + tdb_new = tdb_open(tmp_name, tdb->header.hash_size, + TDB_DEFAULT, O_RDWR|O_CREAT|O_EXCL, + st.st_mode & 0777); + if (!tdb_new) { + perror(tmp_name); + free(tmp_name); + return 1; + } + + /* lock the old tdb */ + if (tdb_lockall(tdb) != 0) { + fprintf(stderr,"Failed to lock %s\n", old_name); + tdb_close(tdb); + tdb_close(tdb_new); + unlink(tmp_name); + free(tmp_name); + return 1; + } + + failed = 0; + + /* traverse and copy */ + count1 = tdb_traverse(tdb, copy_fn, (void *)tdb_new); + if (count1 < 0 || failed) { + fprintf(stderr,"failed to copy %s\n", old_name); + tdb_close(tdb); + tdb_close(tdb_new); + unlink(tmp_name); + free(tmp_name); + return 1; + } + + /* close the old tdb */ + tdb_close(tdb); + + /* close the new tdb and re-open read-only */ + tdb_close(tdb_new); + tdb_new = tdb_open(tmp_name, 0, TDB_DEFAULT, O_RDONLY, 0); + if (!tdb_new) { + fprintf(stderr,"failed to reopen %s\n", tmp_name); + unlink(tmp_name); + perror(tmp_name); + free(tmp_name); + return 1; + } + + /* traverse the new tdb to confirm */ + count2 = tdb_traverse(tdb_new, test_fn, 0); + if (count2 != count1) { + fprintf(stderr,"failed to copy %s\n", old_name); + tdb_close(tdb_new); + unlink(tmp_name); + free(tmp_name); + return 1; + } + + /* make sure the new tdb has reached stable storage */ + fsync(tdb_new->fd); + + /* close the new tdb and rename it to .bak */ + tdb_close(tdb_new); + unlink(new_name); + if (rename(tmp_name, new_name) != 0) { + perror(new_name); + free(tmp_name); + return 1; + } + + printf("%s : %d records\n", old_name, count1); + free(tmp_name); + + return 0; +} + + + +/* + verify a tdb and if it is corrupt then restore from *.bak +*/ +static int verify_tdb(const char *fname, const char *bak_name) +{ + TDB_CONTEXT *tdb; + int count = -1; + + /* open the tdb */ + tdb = tdb_open(fname, 0, 0, O_RDONLY, 0); + + /* traverse the tdb, then close it */ + if (tdb) { + count = tdb_traverse(tdb, test_fn, NULL); + tdb_close(tdb); + } + + /* count is < 0 means an error */ + if (count < 0) { + printf("restoring %s\n", fname); + return backup_tdb(bak_name, fname); + } + + printf("%s : %d records\n", fname, count); + + return 0; +} + + +/* + see if one file is newer than another +*/ +static int file_newer(const char *fname1, const char *fname2) +{ + struct stat st1, st2; + if (stat(fname1, &st1) != 0) { + return 0; + } + if (stat(fname2, &st2) != 0) { + return 1; + } + return (st1.st_mtime > st2.st_mtime); +} + +static void usage(void) +{ + printf("Usage: tdbbackup [options] <fname...>\n\n"); + printf(" -h this help message\n"); + printf(" -s suffix set the backup suffix\n"); + printf(" -v veryify mode (restore if corrupt)\n"); +} + + + int main(int argc, char *argv[]) +{ + int i; + int ret = 0; + int c; + int verify = 0; + char *suffix = ".bak"; + extern int optind; + extern char *optarg; + + while ((c = getopt(argc, argv, "vhs:")) != -1) { + switch (c) { + case 'h': + usage(); + exit(0); + case 'v': + verify = 1; + break; + case 's': + suffix = optarg; + break; + } + } + + argc -= optind; + argv += optind; + + if (argc < 1) { + usage(); + exit(1); + } + + for (i=0; i<argc; i++) { + const char *fname = argv[i]; + char *bak_name; + + bak_name = add_suffix(fname, suffix); + + if (verify) { + if (verify_tdb(fname, bak_name) != 0) { + ret = 1; + } + } else { + if (file_newer(fname, bak_name) && + backup_tdb(fname, bak_name) != 0) { + ret = 1; + } + } + + free(bak_name); + } + + return ret; +} + +#ifdef VALGRIND +size_t valgrind_strlen(const char *s) +{ + size_t count; + for(count = 0; *s++; count++) + ; + return count; +} +#endif |