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.
8 /*****************************************************************************
9 Tunable configuration parameters for the Berkeley DB back end
10 *****************************************************************************/
12 /* Citadel will checkpoint the db at the end of every session, but only if
13 * the specified number of kilobytes has been written, or if the specified
14 * number of minutes has passed, since the last checkpoint.
16 #define MAX_CHECKPOINT_KBYTES 256
17 #define MAX_CHECKPOINT_MINUTES 15
19 /*****************************************************************************/
30 #if DB_VERSION_MAJOR < 5
31 #error Citadel requires Berkeley DB v5.0 or newer. Please upgrade.
34 #include <libcitadel.h>
35 #include "ctdl_module.h"
37 #include "citserver.h"
40 static DB *dbp[MAXCDB]; /* One DB handle for each Citadel database */
41 static DB_ENV *dbenv; /* The DB environment (global) */
44 void cdb_abort(void) {
45 syslog(LOG_DEBUG, "db: citserver is stopping in order to prevent data loss. uid=%d gid=%d euid=%d egid=%d",
46 getuid(), getgid(), geteuid(), getegid()
52 /* Verbose logging callback */
53 void cdb_verbose_log(const DB_ENV *dbenv, const char *msg, const char *what_is_this) {
54 if (!IsEmptyStr(msg)) {
55 syslog(LOG_DEBUG, "db: %s", msg);
60 /* Verbose logging callback */
61 void cdb_verbose_err(const DB_ENV *dbenv, const char *errpfx, const char *msg) {
62 syslog(LOG_ERR, "db: %s", msg);
66 /* wrapper for txn_abort() that logs/aborts on error */
67 static void txabort(DB_TXN *tid) {
70 ret = tid->abort(tid);
73 syslog(LOG_ERR, "db: txn_abort: %s", db_strerror(ret));
79 /* wrapper for txn_commit() that logs/aborts on error */
80 static void txcommit(DB_TXN *tid) {
83 ret = tid->commit(tid, 0);
86 syslog(LOG_ERR, "db: txn_commit: %s", db_strerror(ret));
92 /* wrapper for txn_begin() that logs/aborts on error */
93 static void txbegin(DB_TXN **tid) {
96 ret = dbenv->txn_begin(dbenv, NULL, tid, 0);
99 syslog(LOG_ERR, "db: txn_begin: %s", db_strerror(ret));
106 static void dbpanic(DB_ENV * env, int errval) {
107 syslog(LOG_ERR, "db: PANIC: %s", db_strerror(errval));
111 static void cclose(DBC * cursor) {
114 if ((ret = cursor->c_close(cursor))) {
115 syslog(LOG_ERR, "db: c_close: %s", db_strerror(ret));
121 static void bailIfCursor(DBC ** cursors, const char *msg) {
124 for (i = 0; i < MAXCDB; i++)
125 if (cursors[i] != NULL) {
126 syslog(LOG_ERR, "db: cursor still in progress on cdb %02x: %s", i, msg);
132 void cdb_check_handles(void) {
133 bailIfCursor(TSD->cursors, "in check_handles");
135 if (TSD->tid != NULL) {
136 syslog(LOG_ERR, "db: transaction still in progress!");
143 * Request a checkpoint of the database. Called once per minute by the thread manager.
145 void cdb_checkpoint(void) {
148 syslog(LOG_DEBUG, "db: -- checkpoint --");
149 ret = dbenv->txn_checkpoint(dbenv, MAX_CHECKPOINT_KBYTES, MAX_CHECKPOINT_MINUTES, 0);
152 syslog(LOG_ERR, "db: cdb_checkpoint() txn_checkpoint: %s", db_strerror(ret));
156 /* After a successful checkpoint, we can cull the unused logs */
157 if (CtdlGetConfigInt("c_auto_cull")) {
158 ret = dbenv->log_set_config(dbenv, DB_LOG_AUTO_REMOVE, 1);
161 ret = dbenv->log_set_config(dbenv, DB_LOG_AUTO_REMOVE, 0);
167 * Open the various databases we'll be using. Any database which
168 * does not exist should be created. Note that we don't need a
169 * critical section here, because there aren't any active threads
170 * manipulating the database yet.
172 void open_databases(void) {
177 int dbversion_major, dbversion_minor, dbversion_patch;
179 syslog(LOG_DEBUG, "db: open_databases() starting");
180 syslog(LOG_DEBUG, "db: Compiled libdb: %s", DB_VERSION_STRING);
181 syslog(LOG_DEBUG, "db: Linked libdb: %s", db_version(&dbversion_major, &dbversion_minor, &dbversion_patch));
182 syslog(LOG_DEBUG, "db: Linked zlib: %s", zlibVersion());
185 * Silently try to create the database subdirectory. If it's already there, no problem.
187 if ((mkdir(ctdl_db_dir, 0700) != 0) && (errno != EEXIST)) {
188 syslog(LOG_ERR, "db: unable to create database directory [%s]: %m", ctdl_db_dir);
190 if (chmod(ctdl_db_dir, 0700) != 0) {
191 syslog(LOG_ERR, "db: unable to set database directory permissions [%s]: %m", ctdl_db_dir);
193 if (chown(ctdl_db_dir, CTDLUID, (-1)) != 0) {
194 syslog(LOG_ERR, "db: unable to set the owner for [%s]: %m", ctdl_db_dir);
196 syslog(LOG_DEBUG, "db: Setting up DB environment");
197 // db_env_set_func_yield((int (*)(u_long, u_long))sched_yield);
198 ret = db_env_create(&dbenv, 0);
200 syslog(LOG_ERR, "db: db_env_create: %s", db_strerror(ret));
201 syslog(LOG_ERR, "db: exit code %d", ret);
204 dbenv->set_errpfx(dbenv, "citserver");
205 dbenv->set_paniccall(dbenv, dbpanic);
206 dbenv->set_errcall(dbenv, cdb_verbose_err);
207 dbenv->set_errpfx(dbenv, "ctdl");
208 dbenv->set_msgcall(dbenv, cdb_verbose_log);
209 dbenv->set_verbose(dbenv, DB_VERB_DEADLOCK, 1);
210 dbenv->set_verbose(dbenv, DB_VERB_RECOVERY, 1);
213 * We want to specify the shared memory buffer pool cachesize,
214 * but everything else is the default.
216 ret = dbenv->set_cachesize(dbenv, 0, 64 * 1024, 0);
218 syslog(LOG_ERR, "db: set_cachesize: %s", db_strerror(ret));
219 dbenv->close(dbenv, 0);
220 syslog(LOG_ERR, "db: exit code %d", ret);
224 if ((ret = dbenv->set_lk_detect(dbenv, DB_LOCK_DEFAULT))) {
225 syslog(LOG_ERR, "db: set_lk_detect: %s", db_strerror(ret));
226 dbenv->close(dbenv, 0);
227 syslog(LOG_ERR, "db: 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, "db: 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, "db: dbenv->open: %s", db_strerror(ret));
236 syslog(LOG_ERR, "db: attempting recovery...");
238 ret = dbenv->open(dbenv, ctdl_db_dir, flags, 0); // try recovery
240 if (ret == DB_RUNRECOVERY) {
241 syslog(LOG_ERR, "db: dbenv->open: %s", db_strerror(ret));
242 syslog(LOG_ERR, "db: 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, "db: dbenv->open: %s", db_strerror(ret));
249 dbenv->close(dbenv, 0);
250 syslog(LOG_ERR, "db: exit code %d", ret);
254 syslog(LOG_INFO, "db: 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, "db: db_create: %s", db_strerror(ret));
259 syslog(LOG_ERR, "db: 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, "db: db_open[%02x]: %s", i, db_strerror(ret));
268 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.");
270 syslog(LOG_ERR, "db: exit code %d", ret);
278 * Make sure we own all the files, because in a few milliseconds we're going to drop root privs.
280 void cdb_chmod_data(void) {
283 char filename[PATH_MAX];
285 dp = opendir(ctdl_db_dir);
287 while (d = readdir(dp), d != NULL) {
288 if (d->d_name[0] != '.') {
289 snprintf(filename, sizeof filename, "%s/%s", ctdl_db_dir, d->d_name);
290 syslog(LOG_DEBUG, "db: chmod(%s, 0600) returned %d", filename, chmod(filename, 0600));
291 syslog(LOG_DEBUG, "db: chown(%s, CTDLUID, -1) returned %d",
292 filename, chown(filename, CTDLUID, (-1))
302 * Close all of the db database files we've opened. This can be done
303 * in a loop, since it's just a bunch of closes.
305 void close_databases(void) {
309 syslog(LOG_INFO, "db: performing final checkpoint");
310 if ((ret = dbenv->txn_checkpoint(dbenv, 0, 0, 0))) {
311 syslog(LOG_ERR, "db: txn_checkpoint: %s", db_strerror(ret));
314 syslog(LOG_INFO, "db: flushing the database logs");
315 if ((ret = dbenv->log_flush(dbenv, NULL))) {
316 syslog(LOG_ERR, "db: log_flush: %s", db_strerror(ret));
319 /* close the tables */
320 syslog(LOG_INFO, "db: closing databases");
321 for (i = 0; i < MAXCDB; ++i) {
322 syslog(LOG_INFO, "db: closing database %02x", i);
323 ret = dbp[i]->close(dbp[i], 0);
325 syslog(LOG_ERR, "db: db_close: %s", db_strerror(ret));
330 // This seemed nifty at the time but did anyone really look at it?
331 // #ifdef DB_STAT_ALL
332 // /* print some statistics... */
333 // dbenv->lock_stat_print(dbenv, DB_STAT_ALL);
336 /* Close the handle. */
337 ret = dbenv->close(dbenv, 0);
339 syslog(LOG_ERR, "db: DBENV->close: %s", db_strerror(ret));
345 * Decompress a database item if it was compressed on disk
347 void cdb_decompress_if_necessary(struct cdbdata *cdb) {
348 static int magic = COMPRESS_MAGIC;
350 if ((cdb == NULL) || (cdb->ptr == NULL) || (cdb->len < sizeof(magic)) || (memcmp(cdb->ptr, &magic, sizeof(magic)))) {
354 /* At this point we know we're looking at a compressed item. */
356 struct CtdlCompressHeader zheader;
357 char *uncompressed_data;
358 char *compressed_data;
359 uLongf destLen, sourceLen;
362 memset(&zheader, 0, sizeof(struct CtdlCompressHeader));
363 cplen = sizeof(struct CtdlCompressHeader);
364 if (sizeof(struct CtdlCompressHeader) > cdb->len) {
367 memcpy(&zheader, cdb->ptr, cplen);
369 compressed_data = cdb->ptr;
370 compressed_data += sizeof(struct CtdlCompressHeader);
372 sourceLen = (uLongf) zheader.compressed_len;
373 destLen = (uLongf) zheader.uncompressed_len;
374 uncompressed_data = malloc(zheader.uncompressed_len);
376 if (uncompress((Bytef *) uncompressed_data,
377 (uLongf *) & destLen, (const Bytef *) compressed_data, (uLong) sourceLen) != Z_OK) {
378 syslog(LOG_ERR, "db: uncompress() error");
383 cdb->len = (size_t) destLen;
384 cdb->ptr = uncompressed_data;
389 * Store a piece of data. Returns 0 if the operation was successful. If a
390 * key already exists it should be overwritten.
392 int cdb_store(int cdb, const void *ckey, int ckeylen, void *cdata, int cdatalen) {
397 struct CtdlCompressHeader zheader;
398 char *compressed_data = NULL;
400 size_t buffer_len = 0;
403 memset(&dkey, 0, sizeof(DBT));
404 memset(&ddata, 0, sizeof(DBT));
406 dkey.data = (void *) ckey;
407 ddata.size = cdatalen;
410 /* Only compress Visit and UseTable records. Everything else is uncompressed. */
411 if ((cdb == CDB_VISIT) || (cdb == CDB_USETABLE)) {
413 zheader.magic = COMPRESS_MAGIC;
414 zheader.uncompressed_len = cdatalen;
415 buffer_len = ((cdatalen * 101) / 100) + 100 + sizeof(struct CtdlCompressHeader);
416 destLen = (uLongf) buffer_len;
417 compressed_data = malloc(buffer_len);
418 if (compress2((Bytef *) (compressed_data + sizeof(struct CtdlCompressHeader)),
419 &destLen, (Bytef *) cdata, (uLongf) cdatalen, 1) != Z_OK) {
420 syslog(LOG_ERR, "db: compress2() error");
423 zheader.compressed_len = (size_t) destLen;
424 memcpy(compressed_data, &zheader, sizeof(struct CtdlCompressHeader));
425 ddata.size = (size_t) (sizeof(struct CtdlCompressHeader) + zheader.compressed_len);
426 ddata.data = compressed_data;
429 if (TSD->tid != NULL) {
430 ret = dbp[cdb]->put(dbp[cdb], // db
431 TSD->tid, // transaction ID
437 syslog(LOG_ERR, "db: cdb_store(%d): %s", cdb, db_strerror(ret));
441 free(compressed_data);
445 bailIfCursor(TSD->cursors, "attempt to write during r/o cursor");
450 if ((ret = dbp[cdb]->put(dbp[cdb], // db
451 tid, // transaction ID
455 if (ret == DB_LOCK_DEADLOCK) {
459 syslog(LOG_ERR, "db: cdb_store(%d): %s", cdb, db_strerror(ret));
465 free(compressed_data);
475 * Delete a piece of data. Returns 0 if the operation was successful.
477 int cdb_delete(int cdb, void *key, int keylen) {
482 memset(&dkey, 0, sizeof dkey);
486 if (TSD->tid != NULL) {
487 ret = dbp[cdb]->del(dbp[cdb], TSD->tid, &dkey, 0);
489 syslog(LOG_ERR, "db: cdb_delete(%d): %s", cdb, db_strerror(ret));
490 if (ret != DB_NOTFOUND) {
495 bailIfCursor(TSD->cursors, "attempt to delete during r/o cursor");
500 if ((ret = dbp[cdb]->del(dbp[cdb], tid, &dkey, 0)) && ret != DB_NOTFOUND) {
501 if (ret == DB_LOCK_DEADLOCK) {
505 syslog(LOG_ERR, "db: cdb_delete(%d): %s", cdb, db_strerror(ret));
516 static DBC *localcursor(int cdb) {
520 if (TSD->cursors[cdb] == NULL) {
521 ret = dbp[cdb]->cursor(dbp[cdb], TSD->tid, &curs, 0);
524 ret = TSD->cursors[cdb]->c_dup(TSD->cursors[cdb], &curs, DB_POSITION);
528 syslog(LOG_ERR, "db: localcursor: %s", db_strerror(ret));
537 * Fetch a piece of data. If not found, returns NULL. Otherwise, it returns
538 * a struct cdbdata which it is the caller's responsibility to free later on
539 * using the cdb_free() routine.
541 struct cdbdata *cdb_fetch(int cdb, const void *key, int keylen) {
543 if (keylen == 0) { // key length zero is impossible
547 struct cdbdata *tempcdb;
551 memset(&dkey, 0, sizeof(DBT));
553 dkey.data = (void *) key;
555 if (TSD->tid != NULL) {
556 memset(&dret, 0, sizeof(DBT));
557 dret.flags = DB_DBT_MALLOC;
558 ret = dbp[cdb]->get(dbp[cdb], TSD->tid, &dkey, &dret, 0);
564 memset(&dret, 0, sizeof(DBT));
565 dret.flags = DB_DBT_MALLOC;
566 curs = localcursor(cdb);
567 ret = curs->c_get(curs, &dkey, &dret, DB_SET);
569 } while (ret == DB_LOCK_DEADLOCK);
572 if ((ret != 0) && (ret != DB_NOTFOUND)) {
573 syslog(LOG_ERR, "db: cdb_fetch(%d): %s", cdb, db_strerror(ret));
581 tempcdb = (struct cdbdata *) malloc(sizeof(struct cdbdata));
582 if (tempcdb == NULL) {
583 syslog(LOG_ERR, "db: cdb_fetch() cannot allocate memory for tempcdb: %m");
585 return NULL; /* make it easier for static analysis... */
588 tempcdb->len = dret.size;
589 tempcdb->ptr = dret.data;
590 cdb_decompress_if_necessary(tempcdb);
597 * Free a cdbdata item.
599 * Note that we only free the 'ptr' portion if it is not NULL. This allows
600 * other code to assume ownership of that memory simply by storing the
601 * pointer elsewhere and then setting 'ptr' to NULL. cdb_free() will then
604 void cdb_free(struct cdbdata *cdb) {
612 void cdb_close_cursor(int cdb) {
613 if (TSD->cursors[cdb] != NULL) {
614 cclose(TSD->cursors[cdb]);
617 TSD->cursors[cdb] = NULL;
622 * Prepare for a sequential search of an entire database.
623 * (There is guaranteed to be no more than one traversal in
624 * progress per thread at any given time.)
626 void cdb_rewind(int cdb) {
629 if (TSD->cursors[cdb] != NULL) {
630 syslog(LOG_ERR, "db: cdb_rewind: must close cursor on database %d before reopening", cdb);
632 /* cclose(TSD->cursors[cdb]); */
636 * Now initialize the cursor
638 ret = dbp[cdb]->cursor(dbp[cdb], TSD->tid, &TSD->cursors[cdb], 0);
640 syslog(LOG_ERR, "db: cdb_rewind: db_cursor: %s", db_strerror(ret));
647 * Fetch the next item in a sequential search. Returns a pointer to a
648 * cdbdata structure, or NULL if we've hit the end.
650 struct cdbdata *cdb_next_item(int cdb) {
652 struct cdbdata *cdbret;
655 /* Initialize the key/data pair so the flags aren't set. */
656 memset(&key, 0, sizeof(key));
657 memset(&data, 0, sizeof(data));
658 data.flags = DB_DBT_MALLOC;
660 ret = TSD->cursors[cdb]->c_get(TSD->cursors[cdb], &key, &data, DB_NEXT);
663 if (ret != DB_NOTFOUND) {
664 syslog(LOG_ERR, "db: cdb_next_item(%d): %s", cdb, db_strerror(ret));
667 cdb_close_cursor(cdb);
668 return NULL; /* presumably, end of file */
671 cdbret = (struct cdbdata *) malloc(sizeof(struct cdbdata));
672 cdbret->len = data.size;
673 cdbret->ptr = data.data;
674 cdb_decompress_if_necessary(cdbret);
681 * Transaction-based stuff. I'm writing this as I bake cookies...
683 void cdb_begin_transaction(void) {
684 bailIfCursor(TSD->cursors, "can't begin transaction during r/o cursor");
686 if (TSD->tid != NULL) {
687 syslog(LOG_ERR, "db: cdb_begin_transaction: ERROR: nested transaction");
695 void cdb_end_transaction(void) {
698 for (i = 0; i < MAXCDB; i++) {
699 if (TSD->cursors[i] != NULL) {
700 syslog(LOG_WARNING, "db: cdb_end_transaction: WARNING: cursor %d still open at transaction end", i);
701 cclose(TSD->cursors[i]);
702 TSD->cursors[i] = NULL;
706 if (TSD->tid == NULL) {
707 syslog(LOG_ERR, "db: cdb_end_transaction: ERROR: txcommit(NULL) !!");
719 * Truncate (delete every record)
721 void cdb_trunc(int cdb) {
726 if (TSD->tid != NULL) {
727 syslog(LOG_ERR, "db: cdb_trunc must not be called in a transaction.");
731 bailIfCursor(TSD->cursors, "attempt to write during r/o cursor");
736 if ((ret = dbp[cdb]->truncate(dbp[cdb], /* db */
737 NULL, /* transaction ID */
738 &count, /* #rows deleted */
740 if (ret == DB_LOCK_DEADLOCK) {
744 syslog(LOG_ERR, "db: cdb_truncate(%d): %s", cdb, db_strerror(ret));
746 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.");
758 // compact (defragment) the database, possibly returning space back to the underlying filesystem
759 void cdb_compact(void) {
763 syslog(LOG_DEBUG, "db: cdb_compact() started");
764 for (i = 0; i < MAXCDB; i++) {
765 syslog(LOG_DEBUG, "db: compacting database %d", i);
766 ret = dbp[i]->compact(dbp[i], NULL, NULL, NULL, NULL, DB_FREE_SPACE, NULL);
768 syslog(LOG_ERR, "db: compact: %s", db_strerror(ret));
771 syslog(LOG_DEBUG, "db: cdb_compact() finished");
775 // Has an item already been seen (is it in the CDB_USETABLE) ?
776 // Returns 0 if it hasn't, 1 if it has
777 // In either case, writes the item to the database for next time.
778 int CheckIfAlreadySeen(StrBuf *guid) {
781 struct cdbdata *cdbut;
783 syslog(LOG_DEBUG, "db: CheckIfAlreadySeen(%s)", ChrPtr(guid));
784 cdbut = cdb_fetch(CDB_USETABLE, SKEY(guid));
790 /* (Re)write the record, to update the timestamp. Zeroing it out makes it compress better. */
791 memset(&ut, 0, sizeof(struct UseTable));
792 memcpy(ut.ut_msgid, SKEY(guid));
793 ut.ut_timestamp = time(NULL);
794 cdb_store(CDB_USETABLE, SKEY(guid), &ut, sizeof(struct UseTable));
799 char *ctdl_module_init_database() {
801 // nothing to do here
804 /* return our module id for the log */