1 // This is a data store backend for the Citadel server which uses Berkeley DB.
3 // Copyright (c) 1987-2023 by the citadel.org team
5 // This program is open source software. Use, duplication, or disclosure
6 // is subject to the terms of the GNU General Public License, version 3.
8 // Citadel will checkpoint the db at the end of every session, but only if
9 // the specified number of kilobytes has been written, or if the specified
10 // number of minutes has passed, since the last checkpoint.
11 #define MAX_CHECKPOINT_KBYTES 256
12 #define MAX_CHECKPOINT_MINUTES 15
14 #include "../../sysdep.h"
23 #if DB_VERSION_MAJOR < 18
24 #error Citadel requires Berkeley DB v18.0 or newer. Please upgrade.
27 #include <libcitadel.h>
28 #include "../../ctdl_module.h"
29 #include "../../control.h"
30 #include "../../citserver.h"
31 #include "../../config.h"
33 void (*cdb_open_databases)(void) = NULL;
34 void (*cdb_close_databases)(void) = NULL;
35 int (*cdb_store)(int, const void *, int, void *, int) = NULL;
36 int (*cdb_delete)(int, void *, int) = NULL;
37 void (*cdb_free)(struct cdbdata *) = NULL;
38 struct cdbdata * (*cdb_next_item)(int) = NULL;
39 void (*cdb_close_cursor)(int) = NULL;
40 void (*cdb_begin_transaction)(void) = NULL;
41 void (*cdb_end_transaction)(void) = NULL;
42 void (*cdb_check_handles)(void) = NULL;
43 void (*cdb_trunc)(int) = NULL;
44 void (*cdb_chmod_data)(void) = NULL;
45 void (*check_handles)(void *) = NULL;
46 void (*cdb_compact)(void) = NULL;
47 void (*cdb_checkpoint)(void) = NULL;
48 void (*cdb_rewind)(int) = NULL;
49 struct cdbdata * (*cdb_fetch)(int, const void *, int) = NULL;
51 static DB *dbp[MAXCDB]; // One DB handle for each Citadel database
52 static DB_ENV *dbenv; // The DB environment (global)
55 void bdb_abort(void) {
56 syslog(LOG_DEBUG, "bdb: citserver is stopping in order to prevent data loss. uid=%d gid=%d euid=%d egid=%d",
57 getuid(), getgid(), geteuid(), getegid()
59 raise(SIGABRT); // This will exit in a way that can produce a core dump if needed.
60 exit(CTDLEXIT_DB); // Exit if the signal failed to end the program.
64 // Verbose logging callback
65 void bdb_verbose_log(const DB_ENV *dbenv, const char *msg, const char *foo) {
66 if (!IsEmptyStr(msg)) {
67 syslog(LOG_DEBUG, "bdb: %s %s", msg, foo);
72 // Verbose logging callback
73 void bdb_verbose_err(const DB_ENV *dbenv, const char *errpfx, const char *msg) {
74 syslog(LOG_ERR, "bdb: %s", msg);
78 // wrapper for txn_abort() that logs/aborts on error
79 static void txabort(DB_TXN *tid) {
82 ret = tid->abort(tid);
85 syslog(LOG_ERR, "bdb: txn_abort: %s", db_strerror(ret));
91 // wrapper for txn_commit() that logs/aborts on error
92 static void txcommit(DB_TXN *tid) {
95 ret = tid->commit(tid, 0);
98 syslog(LOG_ERR, "bdb: txn_commit: %s", db_strerror(ret));
104 // wrapper for txn_begin() that logs/aborts on error
105 static void txbegin(DB_TXN **tid) {
108 ret = dbenv->txn_begin(dbenv, NULL, tid, 0);
111 syslog(LOG_ERR, "bdb: txn_begin: %s", db_strerror(ret));
118 static void dbpanic(DB_ENV *env, int errval) {
119 syslog(LOG_ERR, "bdb: PANIC: %s", db_strerror(errval));
124 static void cclose(DBC *cursor) {
127 if ((ret = cursor->c_close(cursor))) {
128 syslog(LOG_ERR, "bdb: c_close: %s", db_strerror(ret));
134 static void bailIfCursor(DBC **cursors, const char *msg) {
137 for (i = 0; i < MAXCDB; i++)
138 if (cursors[i] != NULL) {
139 syslog(LOG_ERR, "bdb: cursor still in progress on cdb %02x: %s", i, msg);
145 void bdb_check_handles(void) {
146 bailIfCursor(TSD->cursors, "in check_handles");
148 if (TSD->tid != NULL) {
149 syslog(LOG_ERR, "bdb: transaction still in progress!");
155 // Request a checkpoint of the database. Called once per minute by the thread manager.
156 void bdb_checkpoint(void) {
159 syslog(LOG_DEBUG, "bdb: -- checkpoint --");
160 ret = dbenv->txn_checkpoint(dbenv, MAX_CHECKPOINT_KBYTES, MAX_CHECKPOINT_MINUTES, 0);
163 syslog(LOG_ERR, "bdb: bdb_checkpoint() txn_checkpoint: %s", db_strerror(ret));
167 // After a successful checkpoint, we can cull the unused logs
168 if (CtdlGetConfigInt("c_auto_cull")) {
169 ret = dbenv->log_set_config(dbenv, DB_LOG_AUTO_REMOVE, 1);
172 ret = dbenv->log_set_config(dbenv, DB_LOG_AUTO_REMOVE, 0);
177 // Open the various databases we'll be using. Any database which
178 // does not exist should be created. Note that we don't need a
179 // critical section here, because there aren't any active threads
180 // manipulating the database yet.
181 void bdb_open_databases(void) {
186 int dbversion_major, dbversion_minor, dbversion_patch;
188 syslog(LOG_DEBUG, "bdb: bdb_open_databases() starting");
189 syslog(LOG_DEBUG, "bdb: Linked zlib: %s", zlibVersion());
190 syslog(LOG_DEBUG, "bdb: Compiled libdb: %s", DB_VERSION_STRING);
191 syslog(LOG_DEBUG, "bdb: Linked libdb: %s", db_version(&dbversion_major, &dbversion_minor, &dbversion_patch));
193 // Create synthetic integer version numbers and compare them.
194 // Never allow citserver to run with a libdb older then the one with which it was compiled.
195 int compiled_db_version = ( (DB_VERSION_MAJOR * 1000000) + (DB_VERSION_MINOR * 1000) + (DB_VERSION_PATCH) );
196 int linked_db_version = ( (dbversion_major * 1000000) + (dbversion_minor * 1000) + (dbversion_patch) );
197 if (compiled_db_version > linked_db_version) {
198 syslog(LOG_ERR, "bdb: citserver is running with a version of libdb older than the one with which it was compiled.");
199 syslog(LOG_ERR, "bdb: This is an invalid configuration. citserver will now exit to prevent data loss.");
203 // Silently try to create the database subdirectory. If it's already there, no problem.
204 if ((mkdir(ctdl_db_dir, 0700) != 0) && (errno != EEXIST)) {
205 syslog(LOG_ERR, "bdb: database directory [%s] does not exist and could not be created: %m", ctdl_db_dir);
208 if (chmod(ctdl_db_dir, 0700) != 0) {
209 syslog(LOG_ERR, "bdb: unable to set database directory permissions [%s]: %m", ctdl_db_dir);
212 if (chown(ctdl_db_dir, CTDLUID, (-1)) != 0) {
213 syslog(LOG_ERR, "bdb: unable to set the owner for [%s]: %m", ctdl_db_dir);
216 syslog(LOG_DEBUG, "bdb: Setting up DB environment");
217 ret = db_env_create(&dbenv, 0);
219 syslog(LOG_ERR, "bdb: db_env_create: %s", db_strerror(ret));
220 syslog(LOG_ERR, "bdb: exit code %d", ret);
223 dbenv->set_errpfx(dbenv, "citserver");
224 dbenv->set_paniccall(dbenv, dbpanic);
225 dbenv->set_errcall(dbenv, bdb_verbose_err);
226 dbenv->set_msgcall(dbenv, bdb_verbose_log);
227 dbenv->set_verbose(dbenv, DB_VERB_DEADLOCK, 1);
228 dbenv->set_verbose(dbenv, DB_VERB_RECOVERY, 1);
230 // We want to specify the shared memory buffer pool cachesize, but everything else is the default.
231 ret = dbenv->set_cachesize(dbenv, 0, 64 * 1024, 0);
233 syslog(LOG_ERR, "bdb: set_cachesize: %s", db_strerror(ret));
234 dbenv->close(dbenv, 0);
235 syslog(LOG_ERR, "bdb: exit code %d", ret);
239 if ((ret = dbenv->set_lk_detect(dbenv, DB_LOCK_DEFAULT))) {
240 syslog(LOG_ERR, "bdb: set_lk_detect: %s", db_strerror(ret));
241 dbenv->close(dbenv, 0);
242 syslog(LOG_ERR, "bdb: exit code %d", ret);
246 flags = DB_CREATE | DB_INIT_MPOOL | DB_PRIVATE | DB_INIT_TXN | DB_INIT_LOCK | DB_THREAD | DB_INIT_LOG;
247 syslog(LOG_DEBUG, "bdb: dbenv->open(dbenv, %s, %d, 0)", ctdl_db_dir, flags);
248 ret = dbenv->open(dbenv, ctdl_db_dir, flags, 0); // try opening the database cleanly
249 if (ret == DB_RUNRECOVERY) {
250 syslog(LOG_ERR, "bdb: dbenv->open: %s", db_strerror(ret));
251 syslog(LOG_ERR, "bdb: attempting recovery...");
253 ret = dbenv->open(dbenv, ctdl_db_dir, flags, 0); // try recovery
255 if (ret == DB_RUNRECOVERY) {
256 syslog(LOG_ERR, "bdb: dbenv->open: %s", db_strerror(ret));
257 syslog(LOG_ERR, "bdb: attempting catastrophic recovery...");
258 flags &= ~DB_RECOVER;
259 flags |= DB_RECOVER_FATAL;
260 ret = dbenv->open(dbenv, ctdl_db_dir, flags, 0); // try catastrophic recovery
263 syslog(LOG_ERR, "bdb: dbenv->open: %s", db_strerror(ret));
264 dbenv->close(dbenv, 0);
265 syslog(LOG_ERR, "bdb: exit code %d", ret);
269 syslog(LOG_INFO, "bdb: mounting databases");
270 for (i = 0; i < MAXCDB; ++i) {
271 ret = db_create(&dbp[i], dbenv, 0); // Create a database handle
273 syslog(LOG_ERR, "bdb: db_create: %s", db_strerror(ret));
274 syslog(LOG_ERR, "bdb: exit code %d", ret);
278 snprintf(dbfilename, sizeof dbfilename, "cdb.%02x", i); // table names by number
279 ret = dbp[i]->open(dbp[i], NULL, dbfilename, NULL, DB_BTREE, DB_CREATE | DB_AUTO_COMMIT | DB_THREAD, 0600);
281 syslog(LOG_ERR, "bdb: db_open[%02x]: %s", i, db_strerror(ret));
283 syslog(LOG_ERR, "bdb: You may need to tune your database; please check http://www.citadel.org for more information.");
285 syslog(LOG_ERR, "bdb: exit code %d", ret);
292 // Make sure we own all the files, because in a few milliseconds we're going to drop root privs.
293 void bdb_chmod_data(void) {
296 char filename[PATH_MAX];
298 dp = opendir(ctdl_db_dir);
300 while (d = readdir(dp), d != NULL) {
301 if (d->d_name[0] != '.') {
302 snprintf(filename, sizeof filename, "%s/%s", ctdl_db_dir, d->d_name);
303 syslog(LOG_DEBUG, "bdb: chmod(%s, 0600) returned %d", filename, chmod(filename, 0600));
304 syslog(LOG_DEBUG, "bdb: chown(%s, CTDLUID, -1) returned %d", filename, chown(filename, CTDLUID, (-1)));
312 // Close all of the db database files we've opened. This can be done in a loop, since it's just a bunch of closes.
313 void bdb_close_databases(void) {
317 static int closing = 0;
318 while (closing == 1) {
319 syslog(LOG_INFO, "bdb: already closing");
323 syslog(LOG_INFO, "bdb: performing final checkpoint");
324 if ((ret = dbenv->txn_checkpoint(dbenv, 0, 0, 0))) {
325 syslog(LOG_ERR, "bdb: txn_checkpoint: %s", db_strerror(ret));
328 syslog(LOG_INFO, "bdb: flushing the database logs");
329 if ((ret = dbenv->log_flush(dbenv, NULL))) {
330 syslog(LOG_ERR, "bdb: log_flush: %s", db_strerror(ret));
334 syslog(LOG_INFO, "bdb: closing databases");
335 for (i = 0; i < MAXCDB; ++i) {
336 syslog(LOG_INFO, "bdb: closing database %02x", i);
337 ret = dbp[i]->close(dbp[i], 0);
339 syslog(LOG_ERR, "bdb: db_close: %s", db_strerror(ret));
344 ret = dbenv->close(dbenv, DB_FORCESYNC);
346 syslog(LOG_ERR, "bdb: DBENV->close: %s", db_strerror(ret));
351 // Decompress a database item if it was compressed on disk
352 void bdb_decompress_if_necessary(struct cdbdata *cdb) {
353 static int magic = COMPRESS_MAGIC;
355 if ((cdb == NULL) || (cdb->ptr == NULL) || (cdb->len < sizeof(magic)) || (memcmp(cdb->ptr, &magic, sizeof(magic)))) {
359 // At this point we know we're looking at a compressed item.
361 struct CtdlCompressHeader zheader;
362 char *uncompressed_data;
363 char *compressed_data;
364 uLongf destLen, sourceLen;
367 memset(&zheader, 0, sizeof(struct CtdlCompressHeader));
368 cplen = sizeof(struct CtdlCompressHeader);
369 if (sizeof(struct CtdlCompressHeader) > cdb->len) {
372 memcpy(&zheader, cdb->ptr, cplen);
374 compressed_data = cdb->ptr;
375 compressed_data += sizeof(struct CtdlCompressHeader);
377 sourceLen = (uLongf) zheader.compressed_len;
378 destLen = (uLongf) zheader.uncompressed_len;
379 uncompressed_data = malloc(zheader.uncompressed_len);
381 if (uncompress((Bytef *) uncompressed_data,
382 (uLongf *) &destLen, (const Bytef *) compressed_data, (uLong) sourceLen) != Z_OK) {
383 syslog(LOG_ERR, "bdb: uncompress() error");
388 cdb->len = (size_t) destLen;
389 cdb->ptr = uncompressed_data;
393 // Store a piece of data. Returns 0 if the operation was successful. If a
394 // key already exists it should be overwritten.
395 int bdb_store(int cdb, const void *ckey, int ckeylen, void *cdata, int cdatalen) {
400 struct CtdlCompressHeader zheader;
401 char *compressed_data = NULL;
403 size_t buffer_len = 0;
406 memset(&dkey, 0, sizeof(DBT));
407 memset(&ddata, 0, sizeof(DBT));
409 dkey.data = (void *) ckey;
410 ddata.size = cdatalen;
413 // "visit" records are numerous and have big, mostly-empty string buffers in them.
414 // If we compress these we can get them down to 1% of their size most of the time.
415 if (cdb == CDB_VISIT) {
417 zheader.magic = COMPRESS_MAGIC;
418 zheader.uncompressed_len = cdatalen;
419 buffer_len = ((cdatalen * 101) / 100) + 100 + sizeof(struct CtdlCompressHeader);
420 destLen = (uLongf) buffer_len;
421 compressed_data = malloc(buffer_len);
422 if (compress2((Bytef *) (compressed_data + sizeof(struct CtdlCompressHeader)), &destLen, (Bytef *) cdata, (uLongf) cdatalen, 1) != Z_OK) {
423 syslog(LOG_ERR, "bdb: compress2() error");
426 zheader.compressed_len = (size_t) destLen;
427 memcpy(compressed_data, &zheader, sizeof(struct CtdlCompressHeader));
428 ddata.size = (size_t) (sizeof(struct CtdlCompressHeader) + zheader.compressed_len);
429 ddata.data = compressed_data;
432 if (TSD->tid != NULL) {
433 ret = dbp[cdb]->put(dbp[cdb], // db
434 TSD->tid, // transaction ID
440 syslog(LOG_ERR, "bdb: bdb_store(%d): %s", cdb, db_strerror(ret));
444 free(compressed_data);
449 bailIfCursor(TSD->cursors, "attempt to write during r/o cursor");
454 if ((ret = dbp[cdb]->put(dbp[cdb], // db
455 tid, // transaction ID
459 if (ret == DB_LOCK_DEADLOCK) {
464 syslog(LOG_ERR, "bdb: bdb_store(%d): %s", cdb, db_strerror(ret));
471 free(compressed_data);
480 // Delete a piece of data. Returns 0 if the operation was successful.
481 int bdb_delete(int cdb, void *key, int keylen) {
486 memset(&dkey, 0, sizeof dkey);
490 if (TSD->tid != NULL) {
491 ret = dbp[cdb]->del(dbp[cdb], TSD->tid, &dkey, 0);
493 syslog(LOG_ERR, "bdb: bdb_delete(%d): %s", cdb, db_strerror(ret));
494 if (ret != DB_NOTFOUND) {
500 bailIfCursor(TSD->cursors, "attempt to delete during r/o cursor");
505 if ((ret = dbp[cdb]->del(dbp[cdb], tid, &dkey, 0)) && ret != DB_NOTFOUND) {
506 if (ret == DB_LOCK_DEADLOCK) {
511 syslog(LOG_ERR, "bdb: bdb_delete(%d): %s", cdb, db_strerror(ret));
523 static DBC *localcursor(int cdb) {
527 if (TSD->cursors[cdb] == NULL) {
528 ret = dbp[cdb]->cursor(dbp[cdb], TSD->tid, &curs, 0);
531 ret = TSD->cursors[cdb]->c_dup(TSD->cursors[cdb], &curs, DB_POSITION);
535 syslog(LOG_ERR, "bdb: localcursor: %s", db_strerror(ret));
543 // Fetch a piece of data. If not found, returns NULL. Otherwise, it returns
544 // a struct cdbdata which it is the caller's responsibility to free later on
545 // using the bdb_free() routine.
546 struct cdbdata *bdb_fetch(int cdb, const void *key, int keylen) {
548 if (keylen == 0) { // key length zero is impossible
552 struct cdbdata *tempcdb;
556 memset(&dkey, 0, sizeof(DBT));
558 dkey.data = (void *) key;
560 if (TSD->tid != NULL) {
561 memset(&dret, 0, sizeof(DBT));
562 dret.flags = DB_DBT_MALLOC;
563 ret = dbp[cdb]->get(dbp[cdb], TSD->tid, &dkey, &dret, 0);
569 memset(&dret, 0, sizeof(DBT));
570 dret.flags = DB_DBT_MALLOC;
571 curs = localcursor(cdb);
572 ret = curs->c_get(curs, &dkey, &dret, DB_SET);
574 } while (ret == DB_LOCK_DEADLOCK);
577 if ((ret != 0) && (ret != DB_NOTFOUND)) {
578 syslog(LOG_ERR, "bdb: bdb_fetch(%d): %s", cdb, db_strerror(ret));
586 tempcdb = (struct cdbdata *) malloc(sizeof(struct cdbdata));
587 if (tempcdb == NULL) {
588 syslog(LOG_ERR, "bdb: bdb_fetch() cannot allocate memory for tempcdb: %m");
592 tempcdb->len = dret.size;
593 tempcdb->ptr = dret.data;
594 bdb_decompress_if_necessary(tempcdb);
600 // Free a cdbdata item.
602 // Note that we only free the 'ptr' portion if it is not NULL. This allows
603 // other code to assume ownership of that memory simply by storing the
604 // pointer elsewhere and then setting 'ptr' to NULL. bdb_free() will then
606 void bdb_free(struct cdbdata *cdb) {
614 void bdb_close_cursor(int cdb) {
615 if (TSD->cursors[cdb] != NULL) {
616 cclose(TSD->cursors[cdb]);
619 TSD->cursors[cdb] = NULL;
623 // Prepare for a sequential search of an entire database.
624 // (There is guaranteed to be no more than one traversal in
625 // progress per thread at any given time.)
626 void bdb_rewind(int cdb) {
629 if (TSD->cursors[cdb] != NULL) {
630 syslog(LOG_ERR, "bdb: bdb_rewind: must close cursor on database %d before reopening", cdb);
632 // cclose(TSD->cursors[cdb]);
635 // Now initialize the cursor
636 ret = dbp[cdb]->cursor(dbp[cdb], TSD->tid, &TSD->cursors[cdb], 0);
638 syslog(LOG_ERR, "bdb: bdb_rewind: db_cursor: %s", db_strerror(ret));
644 // Fetch the next item in a sequential search. Returns a pointer to a
645 // cdbdata structure, or NULL if we've hit the end.
646 struct cdbdata *bdb_next_item(int cdb) {
648 struct cdbdata *cdbret;
651 // Initialize the key/data pair so the flags aren't set.
652 memset(&key, 0, sizeof(key));
653 memset(&data, 0, sizeof(data));
654 data.flags = DB_DBT_MALLOC;
656 ret = TSD->cursors[cdb]->c_get(TSD->cursors[cdb], &key, &data, DB_NEXT);
659 if (ret != DB_NOTFOUND) {
660 syslog(LOG_ERR, "bdb: bdb_next_item(%d): %s", cdb, db_strerror(ret));
663 bdb_close_cursor(cdb);
664 return NULL; // presumably, end of file
667 cdbret = (struct cdbdata *) malloc(sizeof(struct cdbdata));
668 cdbret->len = data.size;
669 cdbret->ptr = data.data;
670 bdb_decompress_if_necessary(cdbret);
676 // Transaction-based stuff. I'm writing this as I bake cookies...
677 void bdb_begin_transaction(void) {
678 bailIfCursor(TSD->cursors, "can't begin transaction during r/o cursor");
680 if (TSD->tid != NULL) {
681 syslog(LOG_ERR, "bdb: bdb_begin_transaction: ERROR: nested transaction");
689 void bdb_end_transaction(void) {
692 for (i = 0; i < MAXCDB; i++) {
693 if (TSD->cursors[i] != NULL) {
694 syslog(LOG_WARNING, "bdb: bdb_end_transaction: WARNING: cursor %d still open at transaction end", i);
695 cclose(TSD->cursors[i]);
696 TSD->cursors[i] = NULL;
700 if (TSD->tid == NULL) {
701 syslog(LOG_ERR, "bdb: bdb_end_transaction: ERROR: txcommit(NULL) !!");
712 // Truncate (delete every record)
713 void bdb_trunc(int cdb) {
717 if (TSD->tid != NULL) {
718 syslog(LOG_ERR, "bdb: bdb_trunc must not be called in a transaction.");
722 bailIfCursor(TSD->cursors, "attempt to write during r/o cursor");
726 if ((ret = dbp[cdb]->truncate(dbp[cdb], // db
727 NULL, // transaction ID
728 &count, // #rows deleted
730 if (ret == DB_LOCK_DEADLOCK) {
734 syslog(LOG_ERR, "bdb: bdb_truncate(%d): %s", cdb, db_strerror(ret));
736 syslog(LOG_ERR, "bdb: You may need to tune your database; please read http://www.citadel.org for more information.");
745 // compact (defragment) the database, possibly returning space back to the underlying filesystem
746 void bdb_compact(void) {
750 syslog(LOG_DEBUG, "bdb: bdb_compact() started");
751 for (i = 0; i < MAXCDB; i++) {
752 syslog(LOG_DEBUG, "bdb: compacting database %d", i);
753 ret = dbp[i]->compact(dbp[i], NULL, NULL, NULL, NULL, DB_FREE_SPACE, NULL);
755 syslog(LOG_ERR, "bdb: compact: %s", db_strerror(ret));
758 syslog(LOG_DEBUG, "bdb: bdb_compact() finished");
762 // Calling this function activates the Berkeley DB back end.
763 void bdb_init_backend(void) {
764 cdb_compact = bdb_compact;
765 cdb_checkpoint = bdb_checkpoint;
766 cdb_rewind = bdb_rewind;
767 cdb_fetch = bdb_fetch;
768 cdb_open_databases = bdb_open_databases;
769 cdb_close_databases = bdb_close_databases;
770 cdb_store = bdb_store;
771 cdb_delete = bdb_delete;
773 cdb_next_item = bdb_next_item;
774 cdb_close_cursor = bdb_close_cursor;
775 cdb_begin_transaction = bdb_begin_transaction;
776 cdb_end_transaction = bdb_end_transaction;
777 cdb_check_handles = bdb_check_handles;
778 cdb_trunc = bdb_trunc;
779 cdb_chmod_data = bdb_chmod_data;
781 syslog(LOG_INFO, "db: initialized Berkeley DB backend");
785 // This will get split out into a separate file. It will act as a marshal for multiple database backends.
786 void cdb_init_backends(void) {
787 bdb_init_backend(); // For now, Berkeley DB is the only backend, so we always initialize it.