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
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"
30 #include "citserver.h"
33 void (*cdb_compact)(void) = NULL;
34 void (*cdb_checkpoint)(void) = NULL;
36 static DB *dbp[MAXCDB]; // One DB handle for each Citadel database
37 static DB_ENV *dbenv; // The DB environment (global)
40 void cdb_abort(void) {
41 syslog(LOG_DEBUG, "bdb: citserver is stopping in order to prevent data loss. uid=%d gid=%d euid=%d egid=%d",
42 getuid(), getgid(), geteuid(), getegid()
44 raise(SIGABRT); // This will exit in a way that can produce a core dump if needed.
45 exit(CTDLEXIT_DB); // Exit if the signal failed to end the program.
49 // Verbose logging callback
50 void cdb_verbose_log(const DB_ENV *dbenv, const char *msg, const char *foo) {
51 if (!IsEmptyStr(msg)) {
52 syslog(LOG_DEBUG, "bdb: %s %s", msg, foo);
57 // Verbose logging callback
58 void cdb_verbose_err(const DB_ENV *dbenv, const char *errpfx, const char *msg) {
59 syslog(LOG_ERR, "bdb: %s", msg);
63 // wrapper for txn_abort() that logs/aborts on error
64 static void txabort(DB_TXN *tid) {
67 ret = tid->abort(tid);
70 syslog(LOG_ERR, "bdb: txn_abort: %s", db_strerror(ret));
76 // wrapper for txn_commit() that logs/aborts on error
77 static void txcommit(DB_TXN *tid) {
80 ret = tid->commit(tid, 0);
83 syslog(LOG_ERR, "bdb: txn_commit: %s", db_strerror(ret));
89 // wrapper for txn_begin() that logs/aborts on error
90 static void txbegin(DB_TXN **tid) {
93 ret = dbenv->txn_begin(dbenv, NULL, tid, 0);
96 syslog(LOG_ERR, "bdb: txn_begin: %s", db_strerror(ret));
103 static void dbpanic(DB_ENV *env, int errval) {
104 syslog(LOG_ERR, "bdb: PANIC: %s", db_strerror(errval));
109 static void cclose(DBC *cursor) {
112 if ((ret = cursor->c_close(cursor))) {
113 syslog(LOG_ERR, "bdb: c_close: %s", db_strerror(ret));
119 static void bailIfCursor(DBC **cursors, const char *msg) {
122 for (i = 0; i < MAXCDB; i++)
123 if (cursors[i] != NULL) {
124 syslog(LOG_ERR, "bdb: cursor still in progress on cdb %02x: %s", i, msg);
130 void cdb_check_handles(void) {
131 bailIfCursor(TSD->cursors, "in check_handles");
133 if (TSD->tid != NULL) {
134 syslog(LOG_ERR, "bdb: transaction still in progress!");
140 // Request a checkpoint of the database. Called once per minute by the thread manager.
141 void bdb_checkpoint(void) {
144 syslog(LOG_DEBUG, "bdb: -- checkpoint --");
145 ret = dbenv->txn_checkpoint(dbenv, MAX_CHECKPOINT_KBYTES, MAX_CHECKPOINT_MINUTES, 0);
148 syslog(LOG_ERR, "bdb: cdb_checkpoint() txn_checkpoint: %s", db_strerror(ret));
152 // After a successful checkpoint, we can cull the unused logs
153 if (CtdlGetConfigInt("c_auto_cull")) {
154 ret = dbenv->log_set_config(dbenv, DB_LOG_AUTO_REMOVE, 1);
157 ret = dbenv->log_set_config(dbenv, DB_LOG_AUTO_REMOVE, 0);
162 // Open the various databases we'll be using. Any database which
163 // does not exist should be created. Note that we don't need a
164 // critical section here, because there aren't any active threads
165 // manipulating the database yet.
166 void cdb_open_databases(void) {
171 int dbversion_major, dbversion_minor, dbversion_patch;
173 syslog(LOG_DEBUG, "bdb: cdb_open_databases() starting");
174 syslog(LOG_DEBUG, "bdb: Linked zlib: %s", zlibVersion());
175 syslog(LOG_DEBUG, "bdb: Compiled libdb: %s", DB_VERSION_STRING);
176 syslog(LOG_DEBUG, "bdb: Linked libdb: %s", db_version(&dbversion_major, &dbversion_minor, &dbversion_patch));
178 // Create synthetic integer version numbers and compare them.
179 // Never allow citserver to run with a libdb older then the one with which it was compiled.
180 int compiled_db_version = ( (DB_VERSION_MAJOR * 1000000) + (DB_VERSION_MINOR * 1000) + (DB_VERSION_PATCH) );
181 int linked_db_version = ( (dbversion_major * 1000000) + (dbversion_minor * 1000) + (dbversion_patch) );
182 if (compiled_db_version > linked_db_version) {
183 syslog(LOG_ERR, "bdb: citserver is running with a version of libdb older than the one with which it was compiled.");
184 syslog(LOG_ERR, "bdb: This is an invalid configuration. citserver will now exit to prevent data loss.");
188 // Silently try to create the database subdirectory. If it's already there, no problem.
189 if ((mkdir(ctdl_db_dir, 0700) != 0) && (errno != EEXIST)) {
190 syslog(LOG_ERR, "bdb: database directory [%s] does not exist and could not be created: %m", ctdl_db_dir);
193 if (chmod(ctdl_db_dir, 0700) != 0) {
194 syslog(LOG_ERR, "bdb: unable to set database directory permissions [%s]: %m", ctdl_db_dir);
197 if (chown(ctdl_db_dir, CTDLUID, (-1)) != 0) {
198 syslog(LOG_ERR, "bdb: unable to set the owner for [%s]: %m", ctdl_db_dir);
201 syslog(LOG_DEBUG, "bdb: Setting up DB environment");
202 ret = db_env_create(&dbenv, 0);
204 syslog(LOG_ERR, "bdb: db_env_create: %s", db_strerror(ret));
205 syslog(LOG_ERR, "bdb: exit code %d", ret);
208 dbenv->set_errpfx(dbenv, "citserver");
209 dbenv->set_paniccall(dbenv, dbpanic);
210 dbenv->set_errcall(dbenv, cdb_verbose_err);
211 dbenv->set_msgcall(dbenv, cdb_verbose_log);
212 dbenv->set_verbose(dbenv, DB_VERB_DEADLOCK, 1);
213 dbenv->set_verbose(dbenv, DB_VERB_RECOVERY, 1);
215 // We want to specify the shared memory buffer pool cachesize, but everything else is the default.
216 ret = dbenv->set_cachesize(dbenv, 0, 64 * 1024, 0);
218 syslog(LOG_ERR, "bdb: set_cachesize: %s", db_strerror(ret));
219 dbenv->close(dbenv, 0);
220 syslog(LOG_ERR, "bdb: exit code %d", ret);
224 if ((ret = dbenv->set_lk_detect(dbenv, DB_LOCK_DEFAULT))) {
225 syslog(LOG_ERR, "bdb: set_lk_detect: %s", db_strerror(ret));
226 dbenv->close(dbenv, 0);
227 syslog(LOG_ERR, "bdb: exit code %d", ret);
231 flags = DB_CREATE | DB_INIT_MPOOL | DB_PRIVATE | DB_INIT_TXN | DB_INIT_LOCK | DB_THREAD | DB_INIT_LOG;
232 syslog(LOG_DEBUG, "bdb: dbenv->open(dbenv, %s, %d, 0)", ctdl_db_dir, flags);
233 ret = dbenv->open(dbenv, ctdl_db_dir, flags, 0); // try opening the database cleanly
234 if (ret == DB_RUNRECOVERY) {
235 syslog(LOG_ERR, "bdb: dbenv->open: %s", db_strerror(ret));
236 syslog(LOG_ERR, "bdb: attempting recovery...");
238 ret = dbenv->open(dbenv, ctdl_db_dir, flags, 0); // try recovery
240 if (ret == DB_RUNRECOVERY) {
241 syslog(LOG_ERR, "bdb: dbenv->open: %s", db_strerror(ret));
242 syslog(LOG_ERR, "bdb: attempting catastrophic recovery...");
243 flags &= ~DB_RECOVER;
244 flags |= DB_RECOVER_FATAL;
245 ret = dbenv->open(dbenv, ctdl_db_dir, flags, 0); // try catastrophic recovery
248 syslog(LOG_ERR, "bdb: dbenv->open: %s", db_strerror(ret));
249 dbenv->close(dbenv, 0);
250 syslog(LOG_ERR, "bdb: exit code %d", ret);
254 syslog(LOG_INFO, "bdb: mounting databases");
255 for (i = 0; i < MAXCDB; ++i) {
256 ret = db_create(&dbp[i], dbenv, 0); // Create a database handle
258 syslog(LOG_ERR, "bdb: db_create: %s", db_strerror(ret));
259 syslog(LOG_ERR, "bdb: exit code %d", ret);
263 snprintf(dbfilename, sizeof dbfilename, "cdb.%02x", i); // table names by number
264 ret = dbp[i]->open(dbp[i], NULL, dbfilename, NULL, DB_BTREE, DB_CREATE | DB_AUTO_COMMIT | DB_THREAD, 0600);
266 syslog(LOG_ERR, "bdb: db_open[%02x]: %s", i, db_strerror(ret));
268 syslog(LOG_ERR, "bdb: You may need to tune your database; please check http://www.citadel.org for more information.");
270 syslog(LOG_ERR, "bdb: exit code %d", ret);
277 // Make sure we own all the files, because in a few milliseconds we're going to drop root privs.
278 void cdb_chmod_data(void) {
281 char filename[PATH_MAX];
283 dp = opendir(ctdl_db_dir);
285 while (d = readdir(dp), d != NULL) {
286 if (d->d_name[0] != '.') {
287 snprintf(filename, sizeof filename, "%s/%s", ctdl_db_dir, d->d_name);
288 syslog(LOG_DEBUG, "bdb: chmod(%s, 0600) returned %d", filename, chmod(filename, 0600));
289 syslog(LOG_DEBUG, "bdb: chown(%s, CTDLUID, -1) returned %d", filename, chown(filename, CTDLUID, (-1)));
297 // 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.
298 void cdb_close_databases(void) {
302 static int closing = 0;
303 while (closing == 1) {
304 syslog(LOG_INFO, "bdb: already closing");
308 syslog(LOG_INFO, "bdb: performing final checkpoint");
309 if ((ret = dbenv->txn_checkpoint(dbenv, 0, 0, 0))) {
310 syslog(LOG_ERR, "bdb: txn_checkpoint: %s", db_strerror(ret));
313 syslog(LOG_INFO, "bdb: flushing the database logs");
314 if ((ret = dbenv->log_flush(dbenv, NULL))) {
315 syslog(LOG_ERR, "bdb: log_flush: %s", db_strerror(ret));
319 syslog(LOG_INFO, "bdb: closing databases");
320 for (i = 0; i < MAXCDB; ++i) {
321 syslog(LOG_INFO, "bdb: closing database %02x", i);
322 ret = dbp[i]->close(dbp[i], 0);
324 syslog(LOG_ERR, "bdb: db_close: %s", db_strerror(ret));
329 ret = dbenv->close(dbenv, DB_FORCESYNC);
331 syslog(LOG_ERR, "bdb: DBENV->close: %s", db_strerror(ret));
336 // Decompress a database item if it was compressed on disk
337 void cdb_decompress_if_necessary(struct cdbdata *cdb) {
338 static int magic = COMPRESS_MAGIC;
340 if ((cdb == NULL) || (cdb->ptr == NULL) || (cdb->len < sizeof(magic)) || (memcmp(cdb->ptr, &magic, sizeof(magic)))) {
344 // At this point we know we're looking at a compressed item.
346 struct CtdlCompressHeader zheader;
347 char *uncompressed_data;
348 char *compressed_data;
349 uLongf destLen, sourceLen;
352 memset(&zheader, 0, sizeof(struct CtdlCompressHeader));
353 cplen = sizeof(struct CtdlCompressHeader);
354 if (sizeof(struct CtdlCompressHeader) > cdb->len) {
357 memcpy(&zheader, cdb->ptr, cplen);
359 compressed_data = cdb->ptr;
360 compressed_data += sizeof(struct CtdlCompressHeader);
362 sourceLen = (uLongf) zheader.compressed_len;
363 destLen = (uLongf) zheader.uncompressed_len;
364 uncompressed_data = malloc(zheader.uncompressed_len);
366 if (uncompress((Bytef *) uncompressed_data,
367 (uLongf *) &destLen, (const Bytef *) compressed_data, (uLong) sourceLen) != Z_OK) {
368 syslog(LOG_ERR, "bdb: uncompress() error");
373 cdb->len = (size_t) destLen;
374 cdb->ptr = uncompressed_data;
378 // Store a piece of data. Returns 0 if the operation was successful. If a
379 // key already exists it should be overwritten.
380 int cdb_store(int cdb, const void *ckey, int ckeylen, void *cdata, int cdatalen) {
385 struct CtdlCompressHeader zheader;
386 char *compressed_data = NULL;
388 size_t buffer_len = 0;
391 memset(&dkey, 0, sizeof(DBT));
392 memset(&ddata, 0, sizeof(DBT));
394 dkey.data = (void *) ckey;
395 ddata.size = cdatalen;
398 // "visit" records are numerous and have big, mostly-empty string buffers in them.
399 // If we compress these we can get them down to 1% of their size most of the time.
400 if (cdb == CDB_VISIT) {
402 zheader.magic = COMPRESS_MAGIC;
403 zheader.uncompressed_len = cdatalen;
404 buffer_len = ((cdatalen * 101) / 100) + 100 + sizeof(struct CtdlCompressHeader);
405 destLen = (uLongf) buffer_len;
406 compressed_data = malloc(buffer_len);
407 if (compress2((Bytef *) (compressed_data + sizeof(struct CtdlCompressHeader)), &destLen, (Bytef *) cdata, (uLongf) cdatalen, 1) != Z_OK) {
408 syslog(LOG_ERR, "bdb: compress2() error");
411 zheader.compressed_len = (size_t) destLen;
412 memcpy(compressed_data, &zheader, sizeof(struct CtdlCompressHeader));
413 ddata.size = (size_t) (sizeof(struct CtdlCompressHeader) + zheader.compressed_len);
414 ddata.data = compressed_data;
417 if (TSD->tid != NULL) {
418 ret = dbp[cdb]->put(dbp[cdb], // db
419 TSD->tid, // transaction ID
425 syslog(LOG_ERR, "bdb: cdb_store(%d): %s", cdb, db_strerror(ret));
429 free(compressed_data);
434 bailIfCursor(TSD->cursors, "attempt to write during r/o cursor");
439 if ((ret = dbp[cdb]->put(dbp[cdb], // db
440 tid, // transaction ID
444 if (ret == DB_LOCK_DEADLOCK) {
449 syslog(LOG_ERR, "bdb: cdb_store(%d): %s", cdb, db_strerror(ret));
456 free(compressed_data);
465 // Delete a piece of data. Returns 0 if the operation was successful.
466 int cdb_delete(int cdb, void *key, int keylen) {
471 memset(&dkey, 0, sizeof dkey);
475 if (TSD->tid != NULL) {
476 ret = dbp[cdb]->del(dbp[cdb], TSD->tid, &dkey, 0);
478 syslog(LOG_ERR, "bdb: cdb_delete(%d): %s", cdb, db_strerror(ret));
479 if (ret != DB_NOTFOUND) {
485 bailIfCursor(TSD->cursors, "attempt to delete during r/o cursor");
490 if ((ret = dbp[cdb]->del(dbp[cdb], tid, &dkey, 0)) && ret != DB_NOTFOUND) {
491 if (ret == DB_LOCK_DEADLOCK) {
496 syslog(LOG_ERR, "bdb: cdb_delete(%d): %s", cdb, db_strerror(ret));
508 static DBC *localcursor(int cdb) {
512 if (TSD->cursors[cdb] == NULL) {
513 ret = dbp[cdb]->cursor(dbp[cdb], TSD->tid, &curs, 0);
516 ret = TSD->cursors[cdb]->c_dup(TSD->cursors[cdb], &curs, DB_POSITION);
520 syslog(LOG_ERR, "bdb: localcursor: %s", db_strerror(ret));
528 // Fetch a piece of data. If not found, returns NULL. Otherwise, it returns
529 // a struct cdbdata which it is the caller's responsibility to free later on
530 // using the cdb_free() routine.
531 struct cdbdata *cdb_fetch(int cdb, const void *key, int keylen) {
533 if (keylen == 0) { // key length zero is impossible
537 struct cdbdata *tempcdb;
541 memset(&dkey, 0, sizeof(DBT));
543 dkey.data = (void *) key;
545 if (TSD->tid != NULL) {
546 memset(&dret, 0, sizeof(DBT));
547 dret.flags = DB_DBT_MALLOC;
548 ret = dbp[cdb]->get(dbp[cdb], TSD->tid, &dkey, &dret, 0);
554 memset(&dret, 0, sizeof(DBT));
555 dret.flags = DB_DBT_MALLOC;
556 curs = localcursor(cdb);
557 ret = curs->c_get(curs, &dkey, &dret, DB_SET);
559 } while (ret == DB_LOCK_DEADLOCK);
562 if ((ret != 0) && (ret != DB_NOTFOUND)) {
563 syslog(LOG_ERR, "bdb: cdb_fetch(%d): %s", cdb, db_strerror(ret));
571 tempcdb = (struct cdbdata *) malloc(sizeof(struct cdbdata));
572 if (tempcdb == NULL) {
573 syslog(LOG_ERR, "bdb: cdb_fetch() cannot allocate memory for tempcdb: %m");
577 tempcdb->len = dret.size;
578 tempcdb->ptr = dret.data;
579 cdb_decompress_if_necessary(tempcdb);
585 // Free a cdbdata item.
587 // Note that we only free the 'ptr' portion if it is not NULL. This allows
588 // other code to assume ownership of that memory simply by storing the
589 // pointer elsewhere and then setting 'ptr' to NULL. cdb_free() will then
591 void cdb_free(struct cdbdata *cdb) {
599 void cdb_close_cursor(int cdb) {
600 if (TSD->cursors[cdb] != NULL) {
601 cclose(TSD->cursors[cdb]);
604 TSD->cursors[cdb] = NULL;
608 // Prepare for a sequential search of an entire database.
609 // (There is guaranteed to be no more than one traversal in
610 // progress per thread at any given time.)
611 void cdb_rewind(int cdb) {
614 if (TSD->cursors[cdb] != NULL) {
615 syslog(LOG_ERR, "bdb: cdb_rewind: must close cursor on database %d before reopening", cdb);
617 // cclose(TSD->cursors[cdb]);
620 // Now initialize the cursor
621 ret = dbp[cdb]->cursor(dbp[cdb], TSD->tid, &TSD->cursors[cdb], 0);
623 syslog(LOG_ERR, "bdb: cdb_rewind: db_cursor: %s", db_strerror(ret));
629 // Fetch the next item in a sequential search. Returns a pointer to a
630 // cdbdata structure, or NULL if we've hit the end.
631 struct cdbdata *cdb_next_item(int cdb) {
633 struct cdbdata *cdbret;
636 // Initialize the key/data pair so the flags aren't set.
637 memset(&key, 0, sizeof(key));
638 memset(&data, 0, sizeof(data));
639 data.flags = DB_DBT_MALLOC;
641 ret = TSD->cursors[cdb]->c_get(TSD->cursors[cdb], &key, &data, DB_NEXT);
644 if (ret != DB_NOTFOUND) {
645 syslog(LOG_ERR, "bdb: cdb_next_item(%d): %s", cdb, db_strerror(ret));
648 cdb_close_cursor(cdb);
649 return NULL; // presumably, end of file
652 cdbret = (struct cdbdata *) malloc(sizeof(struct cdbdata));
653 cdbret->len = data.size;
654 cdbret->ptr = data.data;
655 cdb_decompress_if_necessary(cdbret);
661 // Transaction-based stuff. I'm writing this as I bake cookies...
662 void cdb_begin_transaction(void) {
663 bailIfCursor(TSD->cursors, "can't begin transaction during r/o cursor");
665 if (TSD->tid != NULL) {
666 syslog(LOG_ERR, "bdb: cdb_begin_transaction: ERROR: nested transaction");
674 void cdb_end_transaction(void) {
677 for (i = 0; i < MAXCDB; i++) {
678 if (TSD->cursors[i] != NULL) {
679 syslog(LOG_WARNING, "bdb: cdb_end_transaction: WARNING: cursor %d still open at transaction end", i);
680 cclose(TSD->cursors[i]);
681 TSD->cursors[i] = NULL;
685 if (TSD->tid == NULL) {
686 syslog(LOG_ERR, "bdb: cdb_end_transaction: ERROR: txcommit(NULL) !!");
697 // Truncate (delete every record)
698 void cdb_trunc(int cdb) {
702 if (TSD->tid != NULL) {
703 syslog(LOG_ERR, "bdb: cdb_trunc must not be called in a transaction.");
707 bailIfCursor(TSD->cursors, "attempt to write during r/o cursor");
711 if ((ret = dbp[cdb]->truncate(dbp[cdb], // db
712 NULL, // transaction ID
713 &count, // #rows deleted
715 if (ret == DB_LOCK_DEADLOCK) {
719 syslog(LOG_ERR, "bdb: cdb_truncate(%d): %s", cdb, db_strerror(ret));
721 syslog(LOG_ERR, "bdb: You may need to tune your database; please read http://www.citadel.org for more information.");
730 // compact (defragment) the database, possibly returning space back to the underlying filesystem
731 void bdb_compact(void) {
735 syslog(LOG_DEBUG, "bdb: cdb_compact() started");
736 for (i = 0; i < MAXCDB; i++) {
737 syslog(LOG_DEBUG, "bdb: compacting database %d", i);
738 ret = dbp[i]->compact(dbp[i], NULL, NULL, NULL, NULL, DB_FREE_SPACE, NULL);
740 syslog(LOG_ERR, "bdb: compact: %s", db_strerror(ret));
743 syslog(LOG_DEBUG, "bdb: cdb_compact() finished");
747 void cdb_init_backends(void) {
748 cdb_compact = bdb_compact;
749 cdb_checkpoint = bdb_checkpoint;
750 syslog(LOG_INFO, "db: initialized Berkeley DB backend");