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Diffstat (limited to 'tools/tdbbackup.c')
| -rw-r--r-- | tools/tdbbackup.c | 370 |
1 files changed, 370 insertions, 0 deletions
diff --git a/tools/tdbbackup.c b/tools/tdbbackup.c new file mode 100644 index 0000000..1125987 --- /dev/null +++ b/tools/tdbbackup.c @@ -0,0 +1,370 @@ +/* + 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 3 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, see <http://www.gnu.org/licenses/>. +*/ + +/* + + 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 "replace.h" +#include "system/locale.h" +#include "system/time.h" +#include "system/filesys.h" +#include "system/wait.h" +#include "tdb.h" + +#ifdef HAVE_GETOPT_H +#include <getopt.h> +#endif + +static int failed; + +static struct tdb_logging_context log_ctx; + +#ifdef PRINTF_ATTRIBUTE +static void tdb_log(struct tdb_context *tdb, enum tdb_debug_level level, const char *format, ...) PRINTF_ATTRIBUTE(3,4); +#endif +static void tdb_log(struct tdb_context *tdb, enum tdb_debug_level level, const char *format, ...) +{ + va_list ap; + + va_start(ap, format); + vfprintf(stdout, format, ap); + va_end(ap); + fflush(stdout); +} + +static char *add_suffix(const char *name, const char *suffix) +{ + char *ret; + int len = strlen(name) + strlen(suffix) + 1; + ret = (char *)malloc(len); + if (!ret) { + fprintf(stderr,"Out of memory!\n"); + exit(1); + } + snprintf(ret, len, "%s%s", name, suffix); + 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_name(tdb_new)); + 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, + int hash_size, int nolock, bool readonly) +{ + 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); + free(tmp_name); + return 1; + } + + /* open the old tdb */ + tdb = tdb_open_ex(old_name, 0, + TDB_DEFAULT | (nolock ? TDB_NOLOCK : 0), + O_RDWR, 0, &log_ctx, NULL); + if (!tdb) { + printf("Failed to open %s\n", old_name); + free(tmp_name); + return 1; + } + + /* create the new tdb */ + unlink(tmp_name); + tdb_new = tdb_open_ex(tmp_name, + hash_size ? hash_size : tdb_hash_size(tdb), + TDB_DEFAULT, + O_RDWR|O_CREAT|O_EXCL, st.st_mode & 0777, + &log_ctx, NULL); + if (!tdb_new) { + perror(tmp_name); + free(tmp_name); + return 1; + } + + if (readonly) { + if (tdb_lockall_read(tdb) != 0) { + printf("Failed to obtain read only lock on old tdb\n"); + tdb_close(tdb); + tdb_close(tdb_new); + unlink(tmp_name); + free(tmp_name); + return 1; + } + } else if (tdb_transaction_start(tdb) != 0) { + printf("Failed to start transaction on db\n"); + tdb_close(tdb); + tdb_close(tdb_new); + unlink(tmp_name); + free(tmp_name); + return 1; + } + + /* lock the backup tdb so that nobody else can change it */ + if (tdb_lockall(tdb_new) != 0) { + printf("Failed to lock backup tdb\n"); + tdb_close(tdb); + tdb_close(tdb_new); + unlink(tmp_name); + free(tmp_name); + return 1; + } + + failed = 0; + + /* traverse and copy */ + if (readonly) { + count1 = tdb_traverse_read(tdb, + copy_fn, + (void *)tdb_new); + } else { + 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); + + /* copy done, unlock the backup tdb */ + tdb_unlockall(tdb_new); + +#ifdef HAVE_FDATASYNC + if (fdatasync(tdb_fd(tdb_new)) != 0) { +#else + if (fsync(tdb_fd(tdb_new)) != 0) { +#endif + /* not fatal */ + fprintf(stderr, "failed to fsync backup file\n"); + } + + /* close the new tdb and re-open read-only */ + tdb_close(tdb_new); + tdb_new = tdb_open_ex(tmp_name, + 0, + TDB_DEFAULT, + O_RDONLY, 0, + &log_ctx, NULL); + 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, NULL); + if (count2 != count1) { + fprintf(stderr,"failed to copy %s\n", old_name); + tdb_close(tdb_new); + unlink(tmp_name); + free(tmp_name); + return 1; + } + + /* close the new tdb and rename it to .bak */ + tdb_close(tdb_new); + if (rename(tmp_name, new_name) != 0) { + perror(new_name); + free(tmp_name); + return 1; + } + + 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_ex(fname, 0, 0, + O_RDONLY, 0, &log_ctx, NULL); + + /* 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, 0, 0, 0); + } + + 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 verify mode (restore if corrupt)\n"); + printf(" -n hashsize set the new hash size for the backup\n"); + printf(" -l open without locking to back up mutex dbs\n"); + printf(" -r open with read only locking\n"); +} + + int main(int argc, char *argv[]) +{ + int i; + int ret = 0; + int c; + int verify = 0; + int hashsize = 0; + int nolock = 0; + bool readonly = false; + const char *suffix = ".bak"; + + log_ctx.log_fn = tdb_log; + + while ((c = getopt(argc, argv, "vhs:n:lr")) != -1) { + switch (c) { + case 'h': + usage(); + exit(0); + case 'v': + verify = 1; + break; + case 's': + suffix = optarg; + break; + case 'n': + hashsize = atoi(optarg); + break; + case 'l': + nolock = 1; + break; + case 'r': + readonly = true; + } + } + + 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, hashsize, + nolock, readonly) != 0) { + ret = 1; + } + } + + free(bak_name); + } + + return ret; +} |