/* 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