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; you can redistribute it and/or
6 // modify it under the terms of the GNU General Public License version 3.
8 // This program is distributed in the hope that it will be useful,
9 // but WITHOUT ANY WARRANTY; without even the implied warranty of
10 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 // GNU General Public License for more details.
13 /*****************************************************************************
14 Tunable configuration parameters for the Berkeley DB back end
15 *****************************************************************************/
17 /* Citadel will checkpoint the db at the end of every session, but only if
18 * the specified number of kilobytes has been written, or if the specified
19 * number of minutes has passed, since the last checkpoint.
21 #define MAX_CHECKPOINT_KBYTES 256
22 #define MAX_CHECKPOINT_MINUTES 15
24 /*****************************************************************************/
35 #if DB_VERSION_MAJOR < 5
36 #error Citadel requires Berkeley DB v5.0 or newer. Please upgrade.
39 #include <libcitadel.h>
40 #include "ctdl_module.h"
42 #include "citserver.h"
45 static DB *dbp[MAXCDB]; /* One DB handle for each Citadel database */
46 static DB_ENV *dbenv; /* The DB environment (global) */
49 void cdb_abort(void) {
50 syslog(LOG_DEBUG, "db: citserver is stopping in order to prevent data loss. uid=%d gid=%d euid=%d egid=%d",
51 getuid(), getgid(), geteuid(), getegid()
57 /* Verbose logging callback */
58 void cdb_verbose_log(const DB_ENV *dbenv, const char *msg, const char *what_is_this) {
59 if (!IsEmptyStr(msg)) {
60 syslog(LOG_DEBUG, "db: %s", msg);
65 /* Verbose logging callback */
66 void cdb_verbose_err(const DB_ENV *dbenv, const char *errpfx, const char *msg) {
67 syslog(LOG_ERR, "db: %s", msg);
71 /* wrapper for txn_abort() that logs/aborts on error */
72 static void txabort(DB_TXN *tid) {
75 ret = tid->abort(tid);
78 syslog(LOG_ERR, "db: txn_abort: %s", db_strerror(ret));
84 /* wrapper for txn_commit() that logs/aborts on error */
85 static void txcommit(DB_TXN *tid) {
88 ret = tid->commit(tid, 0);
91 syslog(LOG_ERR, "db: txn_commit: %s", db_strerror(ret));
97 /* wrapper for txn_begin() that logs/aborts on error */
98 static void txbegin(DB_TXN **tid) {
101 ret = dbenv->txn_begin(dbenv, NULL, tid, 0);
104 syslog(LOG_ERR, "db: txn_begin: %s", db_strerror(ret));
111 static void dbpanic(DB_ENV * env, int errval) {
112 syslog(LOG_ERR, "db: PANIC: %s", db_strerror(errval));
116 static void cclose(DBC * cursor) {
119 if ((ret = cursor->c_close(cursor))) {
120 syslog(LOG_ERR, "db: c_close: %s", db_strerror(ret));
126 static void bailIfCursor(DBC ** cursors, const char *msg) {
129 for (i = 0; i < MAXCDB; i++)
130 if (cursors[i] != NULL) {
131 syslog(LOG_ERR, "db: cursor still in progress on cdb %02x: %s", i, msg);
137 void cdb_check_handles(void) {
138 bailIfCursor(TSD->cursors, "in check_handles");
140 if (TSD->tid != NULL) {
141 syslog(LOG_ERR, "db: transaction still in progress!");
148 * Request a checkpoint of the database. Called once per minute by the thread manager.
150 void cdb_checkpoint(void) {
153 syslog(LOG_DEBUG, "db: -- checkpoint --");
154 ret = dbenv->txn_checkpoint(dbenv, MAX_CHECKPOINT_KBYTES, MAX_CHECKPOINT_MINUTES, 0);
157 syslog(LOG_ERR, "db: cdb_checkpoint() txn_checkpoint: %s", db_strerror(ret));
161 /* After a successful checkpoint, we can cull the unused logs */
162 if (CtdlGetConfigInt("c_auto_cull")) {
163 ret = dbenv->log_set_config(dbenv, DB_LOG_AUTO_REMOVE, 1);
166 ret = dbenv->log_set_config(dbenv, DB_LOG_AUTO_REMOVE, 0);
172 * Open the various databases we'll be using. Any database which
173 * does not exist should be created. Note that we don't need a
174 * critical section here, because there aren't any active threads
175 * manipulating the database yet.
177 void open_databases(void) {
182 int dbversion_major, dbversion_minor, dbversion_patch;
184 syslog(LOG_DEBUG, "db: open_databases() starting");
185 syslog(LOG_DEBUG, "db: Compiled libdb: %s", DB_VERSION_STRING);
186 syslog(LOG_DEBUG, "db: Linked libdb: %s", db_version(&dbversion_major, &dbversion_minor, &dbversion_patch));
187 syslog(LOG_DEBUG, "db: Linked zlib: %s", zlibVersion());
190 * Silently try to create the database subdirectory. If it's already there, no problem.
192 if ((mkdir(ctdl_db_dir, 0700) != 0) && (errno != EEXIST)) {
193 syslog(LOG_ERR, "db: unable to create database directory [%s]: %m", ctdl_db_dir);
195 if (chmod(ctdl_db_dir, 0700) != 0) {
196 syslog(LOG_ERR, "db: unable to set database directory permissions [%s]: %m", ctdl_db_dir);
198 if (chown(ctdl_db_dir, CTDLUID, (-1)) != 0) {
199 syslog(LOG_ERR, "db: unable to set the owner for [%s]: %m", ctdl_db_dir);
201 syslog(LOG_DEBUG, "db: Setting up DB environment");
202 // db_env_set_func_yield((int (*)(u_long, u_long))sched_yield);
203 ret = db_env_create(&dbenv, 0);
205 syslog(LOG_ERR, "db: db_env_create: %s", db_strerror(ret));
206 syslog(LOG_ERR, "db: exit code %d", ret);
209 dbenv->set_errpfx(dbenv, "citserver");
210 dbenv->set_paniccall(dbenv, dbpanic);
211 dbenv->set_errcall(dbenv, cdb_verbose_err);
212 dbenv->set_errpfx(dbenv, "ctdl");
213 dbenv->set_msgcall(dbenv, cdb_verbose_log);
214 dbenv->set_verbose(dbenv, DB_VERB_DEADLOCK, 1);
215 dbenv->set_verbose(dbenv, DB_VERB_RECOVERY, 1);
218 * We want to specify the shared memory buffer pool cachesize,
219 * but everything else is the default.
221 ret = dbenv->set_cachesize(dbenv, 0, 64 * 1024, 0);
223 syslog(LOG_ERR, "db: set_cachesize: %s", db_strerror(ret));
224 dbenv->close(dbenv, 0);
225 syslog(LOG_ERR, "db: exit code %d", ret);
229 if ((ret = dbenv->set_lk_detect(dbenv, DB_LOCK_DEFAULT))) {
230 syslog(LOG_ERR, "db: set_lk_detect: %s", db_strerror(ret));
231 dbenv->close(dbenv, 0);
232 syslog(LOG_ERR, "db: exit code %d", ret);
236 flags = DB_CREATE | DB_INIT_MPOOL | DB_PRIVATE | DB_INIT_TXN | DB_INIT_LOCK | DB_THREAD | DB_INIT_LOG;
237 syslog(LOG_DEBUG, "db: dbenv->open(dbenv, %s, %d, 0)", ctdl_db_dir, flags);
238 ret = dbenv->open(dbenv, ctdl_db_dir, flags, 0); // try opening the database cleanly
239 if (ret == DB_RUNRECOVERY) {
240 syslog(LOG_ERR, "db: dbenv->open: %s", db_strerror(ret));
241 syslog(LOG_ERR, "db: attempting recovery...");
243 ret = dbenv->open(dbenv, ctdl_db_dir, flags, 0); // try recovery
245 if (ret == DB_RUNRECOVERY) {
246 syslog(LOG_ERR, "db: dbenv->open: %s", db_strerror(ret));
247 syslog(LOG_ERR, "db: attempting catastrophic recovery...");
248 flags &= ~DB_RECOVER;
249 flags |= DB_RECOVER_FATAL;
250 ret = dbenv->open(dbenv, ctdl_db_dir, flags, 0); // try catastrophic recovery
253 syslog(LOG_ERR, "db: dbenv->open: %s", db_strerror(ret));
254 dbenv->close(dbenv, 0);
255 syslog(LOG_ERR, "db: exit code %d", ret);
259 syslog(LOG_INFO, "db: mounting databases");
260 for (i = 0; i < MAXCDB; ++i) {
261 ret = db_create(&dbp[i], dbenv, 0); // Create a database handle
263 syslog(LOG_ERR, "db: db_create: %s", db_strerror(ret));
264 syslog(LOG_ERR, "db: exit code %d", ret);
268 snprintf(dbfilename, sizeof dbfilename, "cdb.%02x", i); // table names by number
269 ret = dbp[i]->open(dbp[i], NULL, dbfilename, NULL, DB_BTREE, DB_CREATE | DB_AUTO_COMMIT | DB_THREAD, 0600);
271 syslog(LOG_ERR, "db: db_open[%02x]: %s", i, db_strerror(ret));
273 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.");
275 syslog(LOG_ERR, "db: exit code %d", ret);
283 * Make sure we own all the files, because in a few milliseconds we're going to drop root privs.
285 void cdb_chmod_data(void) {
288 char filename[PATH_MAX];
290 dp = opendir(ctdl_db_dir);
292 while (d = readdir(dp), d != NULL) {
293 if (d->d_name[0] != '.') {
294 snprintf(filename, sizeof filename, "%s/%s", ctdl_db_dir, d->d_name);
295 syslog(LOG_DEBUG, "db: chmod(%s, 0600) returned %d", filename, chmod(filename, 0600));
296 syslog(LOG_DEBUG, "db: chown(%s, CTDLUID, -1) returned %d",
297 filename, chown(filename, CTDLUID, (-1))
307 * Close all of the db database files we've opened. This can be done
308 * in a loop, since it's just a bunch of closes.
310 void close_databases(void) {
314 syslog(LOG_INFO, "db: performing final checkpoint");
315 if ((ret = dbenv->txn_checkpoint(dbenv, 0, 0, 0))) {
316 syslog(LOG_ERR, "db: txn_checkpoint: %s", db_strerror(ret));
319 syslog(LOG_INFO, "db: flushing the database logs");
320 if ((ret = dbenv->log_flush(dbenv, NULL))) {
321 syslog(LOG_ERR, "db: log_flush: %s", db_strerror(ret));
324 /* close the tables */
325 syslog(LOG_INFO, "db: closing databases");
326 for (i = 0; i < MAXCDB; ++i) {
327 syslog(LOG_INFO, "db: closing database %02x", i);
328 ret = dbp[i]->close(dbp[i], 0);
330 syslog(LOG_ERR, "db: db_close: %s", db_strerror(ret));
335 // This seemed nifty at the time but did anyone really look at it?
336 // #ifdef DB_STAT_ALL
337 // /* print some statistics... */
338 // dbenv->lock_stat_print(dbenv, DB_STAT_ALL);
341 /* Close the handle. */
342 ret = dbenv->close(dbenv, 0);
344 syslog(LOG_ERR, "db: DBENV->close: %s", db_strerror(ret));
350 * Decompress a database item if it was compressed on disk
352 void cdb_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, "db: uncompress() error");
388 cdb->len = (size_t) destLen;
389 cdb->ptr = uncompressed_data;
394 * Store a piece of data. Returns 0 if the operation was successful. If a
395 * key already exists it should be overwritten.
397 int cdb_store(int cdb, const void *ckey, int ckeylen, void *cdata, int cdatalen) {
402 struct CtdlCompressHeader zheader;
403 char *compressed_data = NULL;
405 size_t buffer_len = 0;
408 memset(&dkey, 0, sizeof(DBT));
409 memset(&ddata, 0, sizeof(DBT));
411 dkey.data = (void *) ckey;
412 ddata.size = cdatalen;
415 /* Only compress Visit and UseTable records. Everything else is uncompressed. */
416 if ((cdb == CDB_VISIT) || (cdb == CDB_USETABLE)) {
418 zheader.magic = COMPRESS_MAGIC;
419 zheader.uncompressed_len = cdatalen;
420 buffer_len = ((cdatalen * 101) / 100) + 100 + sizeof(struct CtdlCompressHeader);
421 destLen = (uLongf) buffer_len;
422 compressed_data = malloc(buffer_len);
423 if (compress2((Bytef *) (compressed_data + sizeof(struct CtdlCompressHeader)),
424 &destLen, (Bytef *) cdata, (uLongf) cdatalen, 1) != Z_OK) {
425 syslog(LOG_ERR, "db: compress2() error");
428 zheader.compressed_len = (size_t) destLen;
429 memcpy(compressed_data, &zheader, sizeof(struct CtdlCompressHeader));
430 ddata.size = (size_t) (sizeof(struct CtdlCompressHeader) + zheader.compressed_len);
431 ddata.data = compressed_data;
434 if (TSD->tid != NULL) {
435 ret = dbp[cdb]->put(dbp[cdb], // db
436 TSD->tid, // transaction ID
442 syslog(LOG_ERR, "db: cdb_store(%d): %s", cdb, db_strerror(ret));
446 free(compressed_data);
450 bailIfCursor(TSD->cursors, "attempt to write during r/o cursor");
455 if ((ret = dbp[cdb]->put(dbp[cdb], // db
456 tid, // transaction ID
460 if (ret == DB_LOCK_DEADLOCK) {
464 syslog(LOG_ERR, "db: cdb_store(%d): %s", cdb, db_strerror(ret));
470 free(compressed_data);
480 * Delete a piece of data. Returns 0 if the operation was successful.
482 int cdb_delete(int cdb, void *key, int keylen) {
487 memset(&dkey, 0, sizeof dkey);
491 if (TSD->tid != NULL) {
492 ret = dbp[cdb]->del(dbp[cdb], TSD->tid, &dkey, 0);
494 syslog(LOG_ERR, "db: cdb_delete(%d): %s", cdb, db_strerror(ret));
495 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) {
510 syslog(LOG_ERR, "db: cdb_delete(%d): %s", cdb, db_strerror(ret));
521 static DBC *localcursor(int cdb) {
525 if (TSD->cursors[cdb] == NULL) {
526 ret = dbp[cdb]->cursor(dbp[cdb], TSD->tid, &curs, 0);
529 ret = TSD->cursors[cdb]->c_dup(TSD->cursors[cdb], &curs, DB_POSITION);
533 syslog(LOG_ERR, "db: localcursor: %s", db_strerror(ret));
542 * Fetch a piece of data. If not found, returns NULL. Otherwise, it returns
543 * a struct cdbdata which it is the caller's responsibility to free later on
544 * using the cdb_free() routine.
546 struct cdbdata *cdb_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, "db: cdb_fetch(%d): %s", cdb, db_strerror(ret));
586 tempcdb = (struct cdbdata *) malloc(sizeof(struct cdbdata));
587 if (tempcdb == NULL) {
588 syslog(LOG_ERR, "db: cdb_fetch() cannot allocate memory for tempcdb: %m");
590 return NULL; /* make it easier for static analysis... */
593 tempcdb->len = dret.size;
594 tempcdb->ptr = dret.data;
595 cdb_decompress_if_necessary(tempcdb);
602 * Free a cdbdata item.
604 * Note that we only free the 'ptr' portion if it is not NULL. This allows
605 * other code to assume ownership of that memory simply by storing the
606 * pointer elsewhere and then setting 'ptr' to NULL. cdb_free() will then
609 void cdb_free(struct cdbdata *cdb) {
617 void cdb_close_cursor(int cdb) {
618 if (TSD->cursors[cdb] != NULL) {
619 cclose(TSD->cursors[cdb]);
622 TSD->cursors[cdb] = NULL;
627 * Prepare for a sequential search of an entire database.
628 * (There is guaranteed to be no more than one traversal in
629 * progress per thread at any given time.)
631 void cdb_rewind(int cdb) {
634 if (TSD->cursors[cdb] != NULL) {
635 syslog(LOG_ERR, "db: cdb_rewind: must close cursor on database %d before reopening", cdb);
637 /* cclose(TSD->cursors[cdb]); */
641 * Now initialize the cursor
643 ret = dbp[cdb]->cursor(dbp[cdb], TSD->tid, &TSD->cursors[cdb], 0);
645 syslog(LOG_ERR, "db: cdb_rewind: db_cursor: %s", db_strerror(ret));
652 * Fetch the next item in a sequential search. Returns a pointer to a
653 * cdbdata structure, or NULL if we've hit the end.
655 struct cdbdata *cdb_next_item(int cdb) {
657 struct cdbdata *cdbret;
660 /* Initialize the key/data pair so the flags aren't set. */
661 memset(&key, 0, sizeof(key));
662 memset(&data, 0, sizeof(data));
663 data.flags = DB_DBT_MALLOC;
665 ret = TSD->cursors[cdb]->c_get(TSD->cursors[cdb], &key, &data, DB_NEXT);
668 if (ret != DB_NOTFOUND) {
669 syslog(LOG_ERR, "db: cdb_next_item(%d): %s", cdb, db_strerror(ret));
672 cdb_close_cursor(cdb);
673 return NULL; /* presumably, end of file */
676 cdbret = (struct cdbdata *) malloc(sizeof(struct cdbdata));
677 cdbret->len = data.size;
678 cdbret->ptr = data.data;
679 cdb_decompress_if_necessary(cdbret);
686 * Transaction-based stuff. I'm writing this as I bake cookies...
688 void cdb_begin_transaction(void) {
689 bailIfCursor(TSD->cursors, "can't begin transaction during r/o cursor");
691 if (TSD->tid != NULL) {
692 syslog(LOG_ERR, "db: cdb_begin_transaction: ERROR: nested transaction");
700 void cdb_end_transaction(void) {
703 for (i = 0; i < MAXCDB; i++) {
704 if (TSD->cursors[i] != NULL) {
705 syslog(LOG_WARNING, "db: cdb_end_transaction: WARNING: cursor %d still open at transaction end", i);
706 cclose(TSD->cursors[i]);
707 TSD->cursors[i] = NULL;
711 if (TSD->tid == NULL) {
712 syslog(LOG_ERR, "db: cdb_end_transaction: ERROR: txcommit(NULL) !!");
724 * Truncate (delete every record)
726 void cdb_trunc(int cdb) {
731 if (TSD->tid != NULL) {
732 syslog(LOG_ERR, "db: cdb_trunc must not be called in a transaction.");
736 bailIfCursor(TSD->cursors, "attempt to write during r/o cursor");
741 if ((ret = dbp[cdb]->truncate(dbp[cdb], /* db */
742 NULL, /* transaction ID */
743 &count, /* #rows deleted */
745 if (ret == DB_LOCK_DEADLOCK) {
749 syslog(LOG_ERR, "db: cdb_truncate(%d): %s", cdb, db_strerror(ret));
751 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.");
763 // compact (defragment) the database, possibly returning space back to the underlying filesystem
764 void cdb_compact(void) {
768 syslog(LOG_DEBUG, "db: cdb_compact() started");
769 for (i = 0; i < MAXCDB; i++) {
770 syslog(LOG_DEBUG, "db: compacting database %d", i);
771 ret = dbp[i]->compact(dbp[i], NULL, NULL, NULL, NULL, DB_FREE_SPACE, NULL);
773 syslog(LOG_ERR, "db: compact: %s", db_strerror(ret));
776 syslog(LOG_DEBUG, "db: cdb_compact() finished");
780 // Has an item already been seen (is it in the CDB_USETABLE) ?
781 // Returns 0 if it hasn't, 1 if it has
782 // In either case, writes the item to the database for next time.
783 int CheckIfAlreadySeen(StrBuf *guid) {
786 struct cdbdata *cdbut;
788 syslog(LOG_DEBUG, "db: CheckIfAlreadySeen(%s)", ChrPtr(guid));
789 cdbut = cdb_fetch(CDB_USETABLE, SKEY(guid));
795 /* (Re)write the record, to update the timestamp. Zeroing it out makes it compress better. */
796 memset(&ut, 0, sizeof(struct UseTable));
797 memcpy(ut.ut_msgid, SKEY(guid));
798 ut.ut_timestamp = time(NULL);
799 cdb_store(CDB_USETABLE, SKEY(guid), &ut, sizeof(struct UseTable));
804 char *ctdl_module_init_database() {
806 // nothing to do here
809 /* return our module id for the log */