1 // This is a data store backend for the Citadel server which uses Berkeley DB.
3 // Copyright (c) 1987-2022 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.
7 // The program is distributed without any warranty, expressed or implied.
9 /*****************************************************************************
10 Tunable configuration parameters for the Berkeley DB back end
11 *****************************************************************************/
13 /* Citadel will checkpoint the db at the end of every session, but only if
14 * the specified number of kilobytes has been written, or if the specified
15 * number of minutes has passed, since the last checkpoint.
17 #define MAX_CHECKPOINT_KBYTES 256
18 #define MAX_CHECKPOINT_MINUTES 15
20 /*****************************************************************************/
31 #if DB_VERSION_MAJOR < 5
32 #error Citadel requires Berkeley DB v5.0 or newer. Please upgrade.
35 #include <libcitadel.h>
36 #include "ctdl_module.h"
38 #include "citserver.h"
41 static DB *dbp[MAXCDB]; /* One DB handle for each Citadel database */
42 static DB_ENV *dbenv; /* The DB environment (global) */
45 void cdb_abort(void) {
46 syslog(LOG_DEBUG, "db: citserver is stopping in order to prevent data loss. uid=%d gid=%d euid=%d egid=%d",
47 getuid(), getgid(), geteuid(), getegid()
53 /* Verbose logging callback */
54 void cdb_verbose_log(const DB_ENV *dbenv, const char *msg, const char *what_is_this) {
55 if (!IsEmptyStr(msg)) {
56 syslog(LOG_DEBUG, "db: %s", msg);
61 /* Verbose logging callback */
62 void cdb_verbose_err(const DB_ENV *dbenv, const char *errpfx, const char *msg) {
63 syslog(LOG_ERR, "db: %s", msg);
67 /* wrapper for txn_abort() that logs/aborts on error */
68 static void txabort(DB_TXN *tid) {
71 ret = tid->abort(tid);
74 syslog(LOG_ERR, "db: txn_abort: %s", db_strerror(ret));
80 /* wrapper for txn_commit() that logs/aborts on error */
81 static void txcommit(DB_TXN *tid) {
84 ret = tid->commit(tid, 0);
87 syslog(LOG_ERR, "db: txn_commit: %s", db_strerror(ret));
93 /* wrapper for txn_begin() that logs/aborts on error */
94 static void txbegin(DB_TXN **tid) {
97 ret = dbenv->txn_begin(dbenv, NULL, tid, 0);
100 syslog(LOG_ERR, "db: txn_begin: %s", db_strerror(ret));
107 static void dbpanic(DB_ENV * env, int errval) {
108 syslog(LOG_ERR, "db: PANIC: %s", db_strerror(errval));
112 static void cclose(DBC * cursor) {
115 if ((ret = cursor->c_close(cursor))) {
116 syslog(LOG_ERR, "db: c_close: %s", db_strerror(ret));
122 static void bailIfCursor(DBC ** cursors, const char *msg) {
125 for (i = 0; i < MAXCDB; i++)
126 if (cursors[i] != NULL) {
127 syslog(LOG_ERR, "db: cursor still in progress on cdb %02x: %s", i, msg);
133 void cdb_check_handles(void) {
134 bailIfCursor(TSD->cursors, "in check_handles");
136 if (TSD->tid != NULL) {
137 syslog(LOG_ERR, "db: transaction still in progress!");
144 * Request a checkpoint of the database. Called once per minute by the thread manager.
146 void cdb_checkpoint(void) {
149 syslog(LOG_DEBUG, "db: -- checkpoint --");
150 ret = dbenv->txn_checkpoint(dbenv, MAX_CHECKPOINT_KBYTES, MAX_CHECKPOINT_MINUTES, 0);
153 syslog(LOG_ERR, "db: cdb_checkpoint() txn_checkpoint: %s", db_strerror(ret));
157 /* After a successful checkpoint, we can cull the unused logs */
158 if (CtdlGetConfigInt("c_auto_cull")) {
159 ret = dbenv->log_set_config(dbenv, DB_LOG_AUTO_REMOVE, 1);
162 ret = dbenv->log_set_config(dbenv, DB_LOG_AUTO_REMOVE, 0);
168 * Open the various databases we'll be using. Any database which
169 * does not exist should be created. Note that we don't need a
170 * critical section here, because there aren't any active threads
171 * manipulating the database yet.
173 void open_databases(void) {
178 int dbversion_major, dbversion_minor, dbversion_patch;
180 syslog(LOG_DEBUG, "db: open_databases() starting");
181 syslog(LOG_DEBUG, "db: Compiled libdb: %s", DB_VERSION_STRING);
182 syslog(LOG_DEBUG, "db: Linked libdb: %s", db_version(&dbversion_major, &dbversion_minor, &dbversion_patch));
183 syslog(LOG_DEBUG, "db: Linked zlib: %s", zlibVersion());
186 * Silently try to create the database subdirectory. If it's already there, no problem.
188 if ((mkdir(ctdl_db_dir, 0700) != 0) && (errno != EEXIST)) {
189 syslog(LOG_ERR, "db: unable to create database directory [%s]: %m", ctdl_db_dir);
191 if (chmod(ctdl_db_dir, 0700) != 0) {
192 syslog(LOG_ERR, "db: unable to set database directory permissions [%s]: %m", ctdl_db_dir);
194 if (chown(ctdl_db_dir, CTDLUID, (-1)) != 0) {
195 syslog(LOG_ERR, "db: unable to set the owner for [%s]: %m", ctdl_db_dir);
197 syslog(LOG_DEBUG, "db: Setting up DB environment");
198 // db_env_set_func_yield((int (*)(u_long, u_long))sched_yield);
199 ret = db_env_create(&dbenv, 0);
201 syslog(LOG_ERR, "db: db_env_create: %s", db_strerror(ret));
202 syslog(LOG_ERR, "db: exit code %d", ret);
205 dbenv->set_errpfx(dbenv, "citserver");
206 dbenv->set_paniccall(dbenv, dbpanic);
207 dbenv->set_errcall(dbenv, cdb_verbose_err);
208 dbenv->set_errpfx(dbenv, "ctdl");
209 dbenv->set_msgcall(dbenv, cdb_verbose_log);
210 dbenv->set_verbose(dbenv, DB_VERB_DEADLOCK, 1);
211 dbenv->set_verbose(dbenv, DB_VERB_RECOVERY, 1);
214 * We want to specify the shared memory buffer pool cachesize,
215 * but everything else is the default.
217 ret = dbenv->set_cachesize(dbenv, 0, 64 * 1024, 0);
219 syslog(LOG_ERR, "db: set_cachesize: %s", db_strerror(ret));
220 dbenv->close(dbenv, 0);
221 syslog(LOG_ERR, "db: exit code %d", ret);
225 if ((ret = dbenv->set_lk_detect(dbenv, DB_LOCK_DEFAULT))) {
226 syslog(LOG_ERR, "db: set_lk_detect: %s", db_strerror(ret));
227 dbenv->close(dbenv, 0);
228 syslog(LOG_ERR, "db: exit code %d", ret);
232 flags = DB_CREATE | DB_INIT_MPOOL | DB_PRIVATE | DB_INIT_TXN | DB_INIT_LOCK | DB_THREAD | DB_INIT_LOG;
233 syslog(LOG_DEBUG, "db: dbenv->open(dbenv, %s, %d, 0)", ctdl_db_dir, flags);
234 ret = dbenv->open(dbenv, ctdl_db_dir, flags, 0); // try opening the database cleanly
235 if (ret == DB_RUNRECOVERY) {
236 syslog(LOG_ERR, "db: dbenv->open: %s", db_strerror(ret));
237 syslog(LOG_ERR, "db: attempting recovery...");
239 ret = dbenv->open(dbenv, ctdl_db_dir, flags, 0); // try recovery
241 if (ret == DB_RUNRECOVERY) {
242 syslog(LOG_ERR, "db: dbenv->open: %s", db_strerror(ret));
243 syslog(LOG_ERR, "db: attempting catastrophic recovery...");
244 flags &= ~DB_RECOVER;
245 flags |= DB_RECOVER_FATAL;
246 ret = dbenv->open(dbenv, ctdl_db_dir, flags, 0); // try catastrophic recovery
249 syslog(LOG_ERR, "db: dbenv->open: %s", db_strerror(ret));
250 dbenv->close(dbenv, 0);
251 syslog(LOG_ERR, "db: exit code %d", ret);
255 syslog(LOG_INFO, "db: mounting databases");
256 for (i = 0; i < MAXCDB; ++i) {
257 ret = db_create(&dbp[i], dbenv, 0); // Create a database handle
259 syslog(LOG_ERR, "db: db_create: %s", db_strerror(ret));
260 syslog(LOG_ERR, "db: exit code %d", ret);
264 snprintf(dbfilename, sizeof dbfilename, "cdb.%02x", i); // table names by number
265 ret = dbp[i]->open(dbp[i], NULL, dbfilename, NULL, DB_BTREE, DB_CREATE | DB_AUTO_COMMIT | DB_THREAD, 0600);
267 syslog(LOG_ERR, "db: db_open[%02x]: %s", i, db_strerror(ret));
269 syslog(LOG_ERR, "db: You may need to tune your database; please read http://www.citadel.org/doku.php?id=faq:troubleshooting:out_of_lock_entries for more information.");
271 syslog(LOG_ERR, "db: exit code %d", ret);
279 * Make sure we own all the files, because in a few milliseconds we're going to drop root privs.
281 void cdb_chmod_data(void) {
284 char filename[PATH_MAX];
286 dp = opendir(ctdl_db_dir);
288 while (d = readdir(dp), d != NULL) {
289 if (d->d_name[0] != '.') {
290 snprintf(filename, sizeof filename, "%s/%s", ctdl_db_dir, d->d_name);
291 syslog(LOG_DEBUG, "db: chmod(%s, 0600) returned %d", filename, chmod(filename, 0600));
292 syslog(LOG_DEBUG, "db: chown(%s, CTDLUID, -1) returned %d",
293 filename, chown(filename, CTDLUID, (-1))
303 * Close all of the db database files we've opened. This can be done
304 * in a loop, since it's just a bunch of closes.
306 void close_databases(void) {
310 syslog(LOG_INFO, "db: performing final checkpoint");
311 if ((ret = dbenv->txn_checkpoint(dbenv, 0, 0, 0))) {
312 syslog(LOG_ERR, "db: txn_checkpoint: %s", db_strerror(ret));
315 syslog(LOG_INFO, "db: flushing the database logs");
316 if ((ret = dbenv->log_flush(dbenv, NULL))) {
317 syslog(LOG_ERR, "db: log_flush: %s", db_strerror(ret));
320 /* close the tables */
321 syslog(LOG_INFO, "db: closing databases");
322 for (i = 0; i < MAXCDB; ++i) {
323 syslog(LOG_INFO, "db: closing database %02x", i);
324 ret = dbp[i]->close(dbp[i], 0);
326 syslog(LOG_ERR, "db: db_close: %s", db_strerror(ret));
331 // This seemed nifty at the time but did anyone really look at it?
332 // #ifdef DB_STAT_ALL
333 // /* print some statistics... */
334 // dbenv->lock_stat_print(dbenv, DB_STAT_ALL);
337 /* Close the handle. */
338 ret = dbenv->close(dbenv, 0);
340 syslog(LOG_ERR, "db: DBENV->close: %s", db_strerror(ret));
346 * Decompress a database item if it was compressed on disk
348 void cdb_decompress_if_necessary(struct cdbdata *cdb) {
349 static int magic = COMPRESS_MAGIC;
351 if ((cdb == NULL) || (cdb->ptr == NULL) || (cdb->len < sizeof(magic)) || (memcmp(cdb->ptr, &magic, sizeof(magic)))) {
355 /* At this point we know we're looking at a compressed item. */
357 struct CtdlCompressHeader zheader;
358 char *uncompressed_data;
359 char *compressed_data;
360 uLongf destLen, sourceLen;
363 memset(&zheader, 0, sizeof(struct CtdlCompressHeader));
364 cplen = sizeof(struct CtdlCompressHeader);
365 if (sizeof(struct CtdlCompressHeader) > cdb->len) {
368 memcpy(&zheader, cdb->ptr, cplen);
370 compressed_data = cdb->ptr;
371 compressed_data += sizeof(struct CtdlCompressHeader);
373 sourceLen = (uLongf) zheader.compressed_len;
374 destLen = (uLongf) zheader.uncompressed_len;
375 uncompressed_data = malloc(zheader.uncompressed_len);
377 if (uncompress((Bytef *) uncompressed_data,
378 (uLongf *) & destLen, (const Bytef *) compressed_data, (uLong) sourceLen) != Z_OK) {
379 syslog(LOG_ERR, "db: uncompress() error");
384 cdb->len = (size_t) destLen;
385 cdb->ptr = uncompressed_data;
390 * Store a piece of data. Returns 0 if the operation was successful. If a
391 * key already exists it should be overwritten.
393 int cdb_store(int cdb, const void *ckey, int ckeylen, void *cdata, int cdatalen) {
398 struct CtdlCompressHeader zheader;
399 char *compressed_data = NULL;
401 size_t buffer_len = 0;
404 memset(&dkey, 0, sizeof(DBT));
405 memset(&ddata, 0, sizeof(DBT));
407 dkey.data = (void *) ckey;
408 ddata.size = cdatalen;
411 /* Only compress Visit and UseTable records. Everything else is uncompressed. */
412 if ((cdb == CDB_VISIT) || (cdb == CDB_USETABLE)) {
414 zheader.magic = COMPRESS_MAGIC;
415 zheader.uncompressed_len = cdatalen;
416 buffer_len = ((cdatalen * 101) / 100) + 100 + sizeof(struct CtdlCompressHeader);
417 destLen = (uLongf) buffer_len;
418 compressed_data = malloc(buffer_len);
419 if (compress2((Bytef *) (compressed_data + sizeof(struct CtdlCompressHeader)),
420 &destLen, (Bytef *) cdata, (uLongf) cdatalen, 1) != Z_OK) {
421 syslog(LOG_ERR, "db: compress2() error");
424 zheader.compressed_len = (size_t) destLen;
425 memcpy(compressed_data, &zheader, sizeof(struct CtdlCompressHeader));
426 ddata.size = (size_t) (sizeof(struct CtdlCompressHeader) + zheader.compressed_len);
427 ddata.data = compressed_data;
430 if (TSD->tid != NULL) {
431 ret = dbp[cdb]->put(dbp[cdb], // db
432 TSD->tid, // transaction ID
438 syslog(LOG_ERR, "db: cdb_store(%d): %s", cdb, db_strerror(ret));
442 free(compressed_data);
446 bailIfCursor(TSD->cursors, "attempt to write during r/o cursor");
451 if ((ret = dbp[cdb]->put(dbp[cdb], // db
452 tid, // transaction ID
456 if (ret == DB_LOCK_DEADLOCK) {
460 syslog(LOG_ERR, "db: cdb_store(%d): %s", cdb, db_strerror(ret));
466 free(compressed_data);
476 * Delete a piece of data. Returns 0 if the operation was successful.
478 int cdb_delete(int cdb, void *key, int keylen) {
483 memset(&dkey, 0, sizeof dkey);
487 if (TSD->tid != NULL) {
488 ret = dbp[cdb]->del(dbp[cdb], TSD->tid, &dkey, 0);
490 syslog(LOG_ERR, "db: cdb_delete(%d): %s", cdb, db_strerror(ret));
491 if (ret != DB_NOTFOUND) {
496 bailIfCursor(TSD->cursors, "attempt to delete during r/o cursor");
501 if ((ret = dbp[cdb]->del(dbp[cdb], tid, &dkey, 0)) && ret != DB_NOTFOUND) {
502 if (ret == DB_LOCK_DEADLOCK) {
506 syslog(LOG_ERR, "db: cdb_delete(%d): %s", cdb, db_strerror(ret));
517 static DBC *localcursor(int cdb) {
521 if (TSD->cursors[cdb] == NULL) {
522 ret = dbp[cdb]->cursor(dbp[cdb], TSD->tid, &curs, 0);
525 ret = TSD->cursors[cdb]->c_dup(TSD->cursors[cdb], &curs, DB_POSITION);
529 syslog(LOG_ERR, "db: localcursor: %s", db_strerror(ret));
538 * Fetch a piece of data. If not found, returns NULL. Otherwise, it returns
539 * a struct cdbdata which it is the caller's responsibility to free later on
540 * using the cdb_free() routine.
542 struct cdbdata *cdb_fetch(int cdb, const void *key, int keylen) {
544 if (keylen == 0) { // key length zero is impossible
548 struct cdbdata *tempcdb;
552 memset(&dkey, 0, sizeof(DBT));
554 dkey.data = (void *) key;
556 if (TSD->tid != NULL) {
557 memset(&dret, 0, sizeof(DBT));
558 dret.flags = DB_DBT_MALLOC;
559 ret = dbp[cdb]->get(dbp[cdb], TSD->tid, &dkey, &dret, 0);
565 memset(&dret, 0, sizeof(DBT));
566 dret.flags = DB_DBT_MALLOC;
567 curs = localcursor(cdb);
568 ret = curs->c_get(curs, &dkey, &dret, DB_SET);
570 } while (ret == DB_LOCK_DEADLOCK);
573 if ((ret != 0) && (ret != DB_NOTFOUND)) {
574 syslog(LOG_ERR, "db: cdb_fetch(%d): %s", cdb, db_strerror(ret));
582 tempcdb = (struct cdbdata *) malloc(sizeof(struct cdbdata));
583 if (tempcdb == NULL) {
584 syslog(LOG_ERR, "db: cdb_fetch() cannot allocate memory for tempcdb: %m");
586 return NULL; /* make it easier for static analysis... */
589 tempcdb->len = dret.size;
590 tempcdb->ptr = dret.data;
591 cdb_decompress_if_necessary(tempcdb);
598 * Free a cdbdata item.
600 * Note that we only free the 'ptr' portion if it is not NULL. This allows
601 * other code to assume ownership of that memory simply by storing the
602 * pointer elsewhere and then setting 'ptr' to NULL. cdb_free() will then
605 void cdb_free(struct cdbdata *cdb) {
613 void cdb_close_cursor(int cdb) {
614 if (TSD->cursors[cdb] != NULL) {
615 cclose(TSD->cursors[cdb]);
618 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.)
627 void cdb_rewind(int cdb) {
630 if (TSD->cursors[cdb] != NULL) {
631 syslog(LOG_ERR, "db: cdb_rewind: must close cursor on database %d before reopening", cdb);
633 /* cclose(TSD->cursors[cdb]); */
637 * Now initialize the cursor
639 ret = dbp[cdb]->cursor(dbp[cdb], TSD->tid, &TSD->cursors[cdb], 0);
641 syslog(LOG_ERR, "db: cdb_rewind: db_cursor: %s", db_strerror(ret));
648 * Fetch the next item in a sequential search. Returns a pointer to a
649 * cdbdata structure, or NULL if we've hit the end.
651 struct cdbdata *cdb_next_item(int cdb) {
653 struct cdbdata *cdbret;
656 /* Initialize the key/data pair so the flags aren't set. */
657 memset(&key, 0, sizeof(key));
658 memset(&data, 0, sizeof(data));
659 data.flags = DB_DBT_MALLOC;
661 ret = TSD->cursors[cdb]->c_get(TSD->cursors[cdb], &key, &data, DB_NEXT);
664 if (ret != DB_NOTFOUND) {
665 syslog(LOG_ERR, "db: cdb_next_item(%d): %s", cdb, db_strerror(ret));
668 cdb_close_cursor(cdb);
669 return NULL; /* presumably, end of file */
672 cdbret = (struct cdbdata *) malloc(sizeof(struct cdbdata));
673 cdbret->len = data.size;
674 cdbret->ptr = data.data;
675 cdb_decompress_if_necessary(cdbret);
682 * Transaction-based stuff. I'm writing this as I bake cookies...
684 void cdb_begin_transaction(void) {
685 bailIfCursor(TSD->cursors, "can't begin transaction during r/o cursor");
687 if (TSD->tid != NULL) {
688 syslog(LOG_ERR, "db: cdb_begin_transaction: ERROR: nested transaction");
696 void cdb_end_transaction(void) {
699 for (i = 0; i < MAXCDB; i++) {
700 if (TSD->cursors[i] != NULL) {
701 syslog(LOG_WARNING, "db: cdb_end_transaction: WARNING: cursor %d still open at transaction end", i);
702 cclose(TSD->cursors[i]);
703 TSD->cursors[i] = NULL;
707 if (TSD->tid == NULL) {
708 syslog(LOG_ERR, "db: cdb_end_transaction: ERROR: txcommit(NULL) !!");
720 * Truncate (delete every record)
722 void cdb_trunc(int cdb) {
727 if (TSD->tid != NULL) {
728 syslog(LOG_ERR, "db: cdb_trunc must not be called in a transaction.");
732 bailIfCursor(TSD->cursors, "attempt to write during r/o cursor");
737 if ((ret = dbp[cdb]->truncate(dbp[cdb], /* db */
738 NULL, /* transaction ID */
739 &count, /* #rows deleted */
741 if (ret == DB_LOCK_DEADLOCK) {
745 syslog(LOG_ERR, "db: cdb_truncate(%d): %s", cdb, db_strerror(ret));
747 syslog(LOG_ERR, "db: You may need to tune your database; please read http://www.citadel.org/doku.php?id=faq:troubleshooting:out_of_lock_entries for more information.");
759 // compact (defragment) the database, possibly returning space back to the underlying filesystem
760 void cdb_compact(void) {
764 syslog(LOG_DEBUG, "db: cdb_compact() started");
765 for (i = 0; i < MAXCDB; i++) {
766 syslog(LOG_DEBUG, "db: compacting database %d", i);
767 ret = dbp[i]->compact(dbp[i], NULL, NULL, NULL, NULL, DB_FREE_SPACE, NULL);
769 syslog(LOG_ERR, "db: compact: %s", db_strerror(ret));
772 syslog(LOG_DEBUG, "db: cdb_compact() finished");
776 // Has an item already been seen (is it in the CDB_USETABLE) ?
777 // Returns 0 if it hasn't, 1 if it has
778 // In either case, writes the item to the database for next time.
779 int CheckIfAlreadySeen(StrBuf *guid) {
782 struct cdbdata *cdbut;
784 syslog(LOG_DEBUG, "db: CheckIfAlreadySeen(%s)", ChrPtr(guid));
785 cdbut = cdb_fetch(CDB_USETABLE, SKEY(guid));
791 /* (Re)write the record, to update the timestamp. Zeroing it out makes it compress better. */
792 memset(&ut, 0, sizeof(struct UseTable));
793 memcpy(ut.ut_msgid, SKEY(guid));
794 ut.ut_timestamp = time(NULL);
795 cdb_store(CDB_USETABLE, SKEY(guid), &ut, sizeof(struct UseTable));
800 char *ctdl_module_init_database() {
802 // nothing to do here
805 /* return our module id for the log */