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;
35 void (*cdb_rewind)(int) = NULL;
37 static DB *dbp[MAXCDB]; // One DB handle for each Citadel database
38 static DB_ENV *dbenv; // The DB environment (global)
41 void cdb_abort(void) {
42 syslog(LOG_DEBUG, "bdb: citserver is stopping in order to prevent data loss. uid=%d gid=%d euid=%d egid=%d",
43 getuid(), getgid(), geteuid(), getegid()
45 raise(SIGABRT); // This will exit in a way that can produce a core dump if needed.
46 exit(CTDLEXIT_DB); // Exit if the signal failed to end the program.
50 // Verbose logging callback
51 void cdb_verbose_log(const DB_ENV *dbenv, const char *msg, const char *foo) {
52 if (!IsEmptyStr(msg)) {
53 syslog(LOG_DEBUG, "bdb: %s %s", msg, foo);
58 // Verbose logging callback
59 void cdb_verbose_err(const DB_ENV *dbenv, const char *errpfx, const char *msg) {
60 syslog(LOG_ERR, "bdb: %s", msg);
64 // wrapper for txn_abort() that logs/aborts on error
65 static void txabort(DB_TXN *tid) {
68 ret = tid->abort(tid);
71 syslog(LOG_ERR, "bdb: txn_abort: %s", db_strerror(ret));
77 // wrapper for txn_commit() that logs/aborts on error
78 static void txcommit(DB_TXN *tid) {
81 ret = tid->commit(tid, 0);
84 syslog(LOG_ERR, "bdb: txn_commit: %s", db_strerror(ret));
90 // wrapper for txn_begin() that logs/aborts on error
91 static void txbegin(DB_TXN **tid) {
94 ret = dbenv->txn_begin(dbenv, NULL, tid, 0);
97 syslog(LOG_ERR, "bdb: txn_begin: %s", db_strerror(ret));
104 static void dbpanic(DB_ENV *env, int errval) {
105 syslog(LOG_ERR, "bdb: PANIC: %s", db_strerror(errval));
110 static void cclose(DBC *cursor) {
113 if ((ret = cursor->c_close(cursor))) {
114 syslog(LOG_ERR, "bdb: c_close: %s", db_strerror(ret));
120 static void bailIfCursor(DBC **cursors, const char *msg) {
123 for (i = 0; i < MAXCDB; i++)
124 if (cursors[i] != NULL) {
125 syslog(LOG_ERR, "bdb: cursor still in progress on cdb %02x: %s", i, msg);
131 void cdb_check_handles(void) {
132 bailIfCursor(TSD->cursors, "in check_handles");
134 if (TSD->tid != NULL) {
135 syslog(LOG_ERR, "bdb: transaction still in progress!");
141 // Request a checkpoint of the database. Called once per minute by the thread manager.
142 void bdb_checkpoint(void) {
145 syslog(LOG_DEBUG, "bdb: -- checkpoint --");
146 ret = dbenv->txn_checkpoint(dbenv, MAX_CHECKPOINT_KBYTES, MAX_CHECKPOINT_MINUTES, 0);
149 syslog(LOG_ERR, "bdb: cdb_checkpoint() txn_checkpoint: %s", db_strerror(ret));
153 // After a successful checkpoint, we can cull the unused logs
154 if (CtdlGetConfigInt("c_auto_cull")) {
155 ret = dbenv->log_set_config(dbenv, DB_LOG_AUTO_REMOVE, 1);
158 ret = dbenv->log_set_config(dbenv, DB_LOG_AUTO_REMOVE, 0);
163 // Open the various databases we'll be using. Any database which
164 // does not exist should be created. Note that we don't need a
165 // critical section here, because there aren't any active threads
166 // manipulating the database yet.
167 void cdb_open_databases(void) {
172 int dbversion_major, dbversion_minor, dbversion_patch;
174 syslog(LOG_DEBUG, "bdb: cdb_open_databases() starting");
175 syslog(LOG_DEBUG, "bdb: Linked zlib: %s", zlibVersion());
176 syslog(LOG_DEBUG, "bdb: Compiled libdb: %s", DB_VERSION_STRING);
177 syslog(LOG_DEBUG, "bdb: Linked libdb: %s", db_version(&dbversion_major, &dbversion_minor, &dbversion_patch));
179 // Create synthetic integer version numbers and compare them.
180 // Never allow citserver to run with a libdb older then the one with which it was compiled.
181 int compiled_db_version = ( (DB_VERSION_MAJOR * 1000000) + (DB_VERSION_MINOR * 1000) + (DB_VERSION_PATCH) );
182 int linked_db_version = ( (dbversion_major * 1000000) + (dbversion_minor * 1000) + (dbversion_patch) );
183 if (compiled_db_version > linked_db_version) {
184 syslog(LOG_ERR, "bdb: citserver is running with a version of libdb older than the one with which it was compiled.");
185 syslog(LOG_ERR, "bdb: This is an invalid configuration. citserver will now exit to prevent data loss.");
189 // Silently try to create the database subdirectory. If it's already there, no problem.
190 if ((mkdir(ctdl_db_dir, 0700) != 0) && (errno != EEXIST)) {
191 syslog(LOG_ERR, "bdb: database directory [%s] does not exist and could not be created: %m", ctdl_db_dir);
194 if (chmod(ctdl_db_dir, 0700) != 0) {
195 syslog(LOG_ERR, "bdb: unable to set database directory permissions [%s]: %m", ctdl_db_dir);
198 if (chown(ctdl_db_dir, CTDLUID, (-1)) != 0) {
199 syslog(LOG_ERR, "bdb: unable to set the owner for [%s]: %m", ctdl_db_dir);
202 syslog(LOG_DEBUG, "bdb: Setting up DB environment");
203 ret = db_env_create(&dbenv, 0);
205 syslog(LOG_ERR, "bdb: db_env_create: %s", db_strerror(ret));
206 syslog(LOG_ERR, "bdb: 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_msgcall(dbenv, cdb_verbose_log);
213 dbenv->set_verbose(dbenv, DB_VERB_DEADLOCK, 1);
214 dbenv->set_verbose(dbenv, DB_VERB_RECOVERY, 1);
216 // We want to specify the shared memory buffer pool cachesize, but everything else is the default.
217 ret = dbenv->set_cachesize(dbenv, 0, 64 * 1024, 0);
219 syslog(LOG_ERR, "bdb: set_cachesize: %s", db_strerror(ret));
220 dbenv->close(dbenv, 0);
221 syslog(LOG_ERR, "bdb: exit code %d", ret);
225 if ((ret = dbenv->set_lk_detect(dbenv, DB_LOCK_DEFAULT))) {
226 syslog(LOG_ERR, "bdb: set_lk_detect: %s", db_strerror(ret));
227 dbenv->close(dbenv, 0);
228 syslog(LOG_ERR, "bdb: 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, "bdb: 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, "bdb: dbenv->open: %s", db_strerror(ret));
237 syslog(LOG_ERR, "bdb: attempting recovery...");
239 ret = dbenv->open(dbenv, ctdl_db_dir, flags, 0); // try recovery
241 if (ret == DB_RUNRECOVERY) {
242 syslog(LOG_ERR, "bdb: dbenv->open: %s", db_strerror(ret));
243 syslog(LOG_ERR, "bdb: 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, "bdb: dbenv->open: %s", db_strerror(ret));
250 dbenv->close(dbenv, 0);
251 syslog(LOG_ERR, "bdb: exit code %d", ret);
255 syslog(LOG_INFO, "bdb: 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, "bdb: db_create: %s", db_strerror(ret));
260 syslog(LOG_ERR, "bdb: 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, "bdb: db_open[%02x]: %s", i, db_strerror(ret));
269 syslog(LOG_ERR, "bdb: You may need to tune your database; please check http://www.citadel.org for more information.");
271 syslog(LOG_ERR, "bdb: exit code %d", ret);
278 // Make sure we own all the files, because in a few milliseconds we're going to drop root privs.
279 void cdb_chmod_data(void) {
282 char filename[PATH_MAX];
284 dp = opendir(ctdl_db_dir);
286 while (d = readdir(dp), d != NULL) {
287 if (d->d_name[0] != '.') {
288 snprintf(filename, sizeof filename, "%s/%s", ctdl_db_dir, d->d_name);
289 syslog(LOG_DEBUG, "bdb: chmod(%s, 0600) returned %d", filename, chmod(filename, 0600));
290 syslog(LOG_DEBUG, "bdb: chown(%s, CTDLUID, -1) returned %d", filename, chown(filename, CTDLUID, (-1)));
298 // 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.
299 void cdb_close_databases(void) {
303 static int closing = 0;
304 while (closing == 1) {
305 syslog(LOG_INFO, "bdb: already closing");
309 syslog(LOG_INFO, "bdb: performing final checkpoint");
310 if ((ret = dbenv->txn_checkpoint(dbenv, 0, 0, 0))) {
311 syslog(LOG_ERR, "bdb: txn_checkpoint: %s", db_strerror(ret));
314 syslog(LOG_INFO, "bdb: flushing the database logs");
315 if ((ret = dbenv->log_flush(dbenv, NULL))) {
316 syslog(LOG_ERR, "bdb: log_flush: %s", db_strerror(ret));
320 syslog(LOG_INFO, "bdb: closing databases");
321 for (i = 0; i < MAXCDB; ++i) {
322 syslog(LOG_INFO, "bdb: closing database %02x", i);
323 ret = dbp[i]->close(dbp[i], 0);
325 syslog(LOG_ERR, "bdb: db_close: %s", db_strerror(ret));
330 ret = dbenv->close(dbenv, DB_FORCESYNC);
332 syslog(LOG_ERR, "bdb: DBENV->close: %s", db_strerror(ret));
337 // Decompress a database item if it was compressed on disk
338 void cdb_decompress_if_necessary(struct cdbdata *cdb) {
339 static int magic = COMPRESS_MAGIC;
341 if ((cdb == NULL) || (cdb->ptr == NULL) || (cdb->len < sizeof(magic)) || (memcmp(cdb->ptr, &magic, sizeof(magic)))) {
345 // At this point we know we're looking at a compressed item.
347 struct CtdlCompressHeader zheader;
348 char *uncompressed_data;
349 char *compressed_data;
350 uLongf destLen, sourceLen;
353 memset(&zheader, 0, sizeof(struct CtdlCompressHeader));
354 cplen = sizeof(struct CtdlCompressHeader);
355 if (sizeof(struct CtdlCompressHeader) > cdb->len) {
358 memcpy(&zheader, cdb->ptr, cplen);
360 compressed_data = cdb->ptr;
361 compressed_data += sizeof(struct CtdlCompressHeader);
363 sourceLen = (uLongf) zheader.compressed_len;
364 destLen = (uLongf) zheader.uncompressed_len;
365 uncompressed_data = malloc(zheader.uncompressed_len);
367 if (uncompress((Bytef *) uncompressed_data,
368 (uLongf *) &destLen, (const Bytef *) compressed_data, (uLong) sourceLen) != Z_OK) {
369 syslog(LOG_ERR, "bdb: uncompress() error");
374 cdb->len = (size_t) destLen;
375 cdb->ptr = uncompressed_data;
379 // Store a piece of data. Returns 0 if the operation was successful. If a
380 // key already exists it should be overwritten.
381 int cdb_store(int cdb, const void *ckey, int ckeylen, void *cdata, int cdatalen) {
386 struct CtdlCompressHeader zheader;
387 char *compressed_data = NULL;
389 size_t buffer_len = 0;
392 memset(&dkey, 0, sizeof(DBT));
393 memset(&ddata, 0, sizeof(DBT));
395 dkey.data = (void *) ckey;
396 ddata.size = cdatalen;
399 // "visit" records are numerous and have big, mostly-empty string buffers in them.
400 // If we compress these we can get them down to 1% of their size most of the time.
401 if (cdb == CDB_VISIT) {
403 zheader.magic = COMPRESS_MAGIC;
404 zheader.uncompressed_len = cdatalen;
405 buffer_len = ((cdatalen * 101) / 100) + 100 + sizeof(struct CtdlCompressHeader);
406 destLen = (uLongf) buffer_len;
407 compressed_data = malloc(buffer_len);
408 if (compress2((Bytef *) (compressed_data + sizeof(struct CtdlCompressHeader)), &destLen, (Bytef *) cdata, (uLongf) cdatalen, 1) != Z_OK) {
409 syslog(LOG_ERR, "bdb: compress2() error");
412 zheader.compressed_len = (size_t) destLen;
413 memcpy(compressed_data, &zheader, sizeof(struct CtdlCompressHeader));
414 ddata.size = (size_t) (sizeof(struct CtdlCompressHeader) + zheader.compressed_len);
415 ddata.data = compressed_data;
418 if (TSD->tid != NULL) {
419 ret = dbp[cdb]->put(dbp[cdb], // db
420 TSD->tid, // transaction ID
426 syslog(LOG_ERR, "bdb: cdb_store(%d): %s", cdb, db_strerror(ret));
430 free(compressed_data);
435 bailIfCursor(TSD->cursors, "attempt to write during r/o cursor");
440 if ((ret = dbp[cdb]->put(dbp[cdb], // db
441 tid, // transaction ID
445 if (ret == DB_LOCK_DEADLOCK) {
450 syslog(LOG_ERR, "bdb: cdb_store(%d): %s", cdb, db_strerror(ret));
457 free(compressed_data);
466 // Delete a piece of data. Returns 0 if the operation was successful.
467 int cdb_delete(int cdb, void *key, int keylen) {
472 memset(&dkey, 0, sizeof dkey);
476 if (TSD->tid != NULL) {
477 ret = dbp[cdb]->del(dbp[cdb], TSD->tid, &dkey, 0);
479 syslog(LOG_ERR, "bdb: cdb_delete(%d): %s", cdb, db_strerror(ret));
480 if (ret != DB_NOTFOUND) {
486 bailIfCursor(TSD->cursors, "attempt to delete during r/o cursor");
491 if ((ret = dbp[cdb]->del(dbp[cdb], tid, &dkey, 0)) && ret != DB_NOTFOUND) {
492 if (ret == DB_LOCK_DEADLOCK) {
497 syslog(LOG_ERR, "bdb: cdb_delete(%d): %s", cdb, db_strerror(ret));
509 static DBC *localcursor(int cdb) {
513 if (TSD->cursors[cdb] == NULL) {
514 ret = dbp[cdb]->cursor(dbp[cdb], TSD->tid, &curs, 0);
517 ret = TSD->cursors[cdb]->c_dup(TSD->cursors[cdb], &curs, DB_POSITION);
521 syslog(LOG_ERR, "bdb: localcursor: %s", db_strerror(ret));
529 // Fetch a piece of data. If not found, returns NULL. Otherwise, it returns
530 // a struct cdbdata which it is the caller's responsibility to free later on
531 // using the cdb_free() routine.
532 struct cdbdata *cdb_fetch(int cdb, const void *key, int keylen) {
534 if (keylen == 0) { // key length zero is impossible
538 struct cdbdata *tempcdb;
542 memset(&dkey, 0, sizeof(DBT));
544 dkey.data = (void *) key;
546 if (TSD->tid != NULL) {
547 memset(&dret, 0, sizeof(DBT));
548 dret.flags = DB_DBT_MALLOC;
549 ret = dbp[cdb]->get(dbp[cdb], TSD->tid, &dkey, &dret, 0);
555 memset(&dret, 0, sizeof(DBT));
556 dret.flags = DB_DBT_MALLOC;
557 curs = localcursor(cdb);
558 ret = curs->c_get(curs, &dkey, &dret, DB_SET);
560 } while (ret == DB_LOCK_DEADLOCK);
563 if ((ret != 0) && (ret != DB_NOTFOUND)) {
564 syslog(LOG_ERR, "bdb: cdb_fetch(%d): %s", cdb, db_strerror(ret));
572 tempcdb = (struct cdbdata *) malloc(sizeof(struct cdbdata));
573 if (tempcdb == NULL) {
574 syslog(LOG_ERR, "bdb: cdb_fetch() cannot allocate memory for tempcdb: %m");
578 tempcdb->len = dret.size;
579 tempcdb->ptr = dret.data;
580 cdb_decompress_if_necessary(tempcdb);
586 // Free a cdbdata item.
588 // Note that we only free the 'ptr' portion if it is not NULL. This allows
589 // other code to assume ownership of that memory simply by storing the
590 // pointer elsewhere and then setting 'ptr' to NULL. cdb_free() will then
592 void cdb_free(struct cdbdata *cdb) {
600 void cdb_close_cursor(int cdb) {
601 if (TSD->cursors[cdb] != NULL) {
602 cclose(TSD->cursors[cdb]);
605 TSD->cursors[cdb] = NULL;
609 // Prepare for a sequential search of an entire database.
610 // (There is guaranteed to be no more than one traversal in
611 // progress per thread at any given time.)
612 void bdb_rewind(int cdb) {
615 if (TSD->cursors[cdb] != NULL) {
616 syslog(LOG_ERR, "bdb: cdb_rewind: must close cursor on database %d before reopening", cdb);
618 // cclose(TSD->cursors[cdb]);
621 // Now initialize the cursor
622 ret = dbp[cdb]->cursor(dbp[cdb], TSD->tid, &TSD->cursors[cdb], 0);
624 syslog(LOG_ERR, "bdb: cdb_rewind: db_cursor: %s", db_strerror(ret));
630 // Fetch the next item in a sequential search. Returns a pointer to a
631 // cdbdata structure, or NULL if we've hit the end.
632 struct cdbdata *cdb_next_item(int cdb) {
634 struct cdbdata *cdbret;
637 // Initialize the key/data pair so the flags aren't set.
638 memset(&key, 0, sizeof(key));
639 memset(&data, 0, sizeof(data));
640 data.flags = DB_DBT_MALLOC;
642 ret = TSD->cursors[cdb]->c_get(TSD->cursors[cdb], &key, &data, DB_NEXT);
645 if (ret != DB_NOTFOUND) {
646 syslog(LOG_ERR, "bdb: cdb_next_item(%d): %s", cdb, db_strerror(ret));
649 cdb_close_cursor(cdb);
650 return NULL; // presumably, end of file
653 cdbret = (struct cdbdata *) malloc(sizeof(struct cdbdata));
654 cdbret->len = data.size;
655 cdbret->ptr = data.data;
656 cdb_decompress_if_necessary(cdbret);
662 // Transaction-based stuff. I'm writing this as I bake cookies...
663 void cdb_begin_transaction(void) {
664 bailIfCursor(TSD->cursors, "can't begin transaction during r/o cursor");
666 if (TSD->tid != NULL) {
667 syslog(LOG_ERR, "bdb: cdb_begin_transaction: ERROR: nested transaction");
675 void cdb_end_transaction(void) {
678 for (i = 0; i < MAXCDB; i++) {
679 if (TSD->cursors[i] != NULL) {
680 syslog(LOG_WARNING, "bdb: cdb_end_transaction: WARNING: cursor %d still open at transaction end", i);
681 cclose(TSD->cursors[i]);
682 TSD->cursors[i] = NULL;
686 if (TSD->tid == NULL) {
687 syslog(LOG_ERR, "bdb: cdb_end_transaction: ERROR: txcommit(NULL) !!");
698 // Truncate (delete every record)
699 void cdb_trunc(int cdb) {
703 if (TSD->tid != NULL) {
704 syslog(LOG_ERR, "bdb: cdb_trunc must not be called in a transaction.");
708 bailIfCursor(TSD->cursors, "attempt to write during r/o cursor");
712 if ((ret = dbp[cdb]->truncate(dbp[cdb], // db
713 NULL, // transaction ID
714 &count, // #rows deleted
716 if (ret == DB_LOCK_DEADLOCK) {
720 syslog(LOG_ERR, "bdb: cdb_truncate(%d): %s", cdb, db_strerror(ret));
722 syslog(LOG_ERR, "bdb: You may need to tune your database; please read http://www.citadel.org for more information.");
731 // compact (defragment) the database, possibly returning space back to the underlying filesystem
732 void bdb_compact(void) {
736 syslog(LOG_DEBUG, "bdb: cdb_compact() started");
737 for (i = 0; i < MAXCDB; i++) {
738 syslog(LOG_DEBUG, "bdb: compacting database %d", i);
739 ret = dbp[i]->compact(dbp[i], NULL, NULL, NULL, NULL, DB_FREE_SPACE, NULL);
741 syslog(LOG_ERR, "bdb: compact: %s", db_strerror(ret));
744 syslog(LOG_DEBUG, "bdb: cdb_compact() finished");
748 void cdb_init_backends(void) {
749 cdb_compact = bdb_compact;
750 cdb_checkpoint = bdb_checkpoint;
751 cdb_rewind = bdb_rewind;
752 syslog(LOG_INFO, "db: initialized Berkeley DB backend");