2 Unix SMB/CIFS implementation.
4 trivial database library
6 Copyright (C) Andrew Tridgell 1999-2005
7 Copyright (C) Paul `Rusty' Russell 2000
8 Copyright (C) Jeremy Allison 2000-2003
10 ** NOTE! The following LGPL license applies to the tdb
11 ** library. This does NOT imply that all of Samba is released
14 This library is free software; you can redistribute it and/or
15 modify it under the terms of the GNU Lesser General Public
16 License as published by the Free Software Foundation; either
17 version 3 of the License, or (at your option) any later version.
19 This library is distributed in the hope that it will be useful,
20 but WITHOUT ANY WARRANTY; without even the implied warranty of
21 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22 Lesser General Public License for more details.
24 You should have received a copy of the GNU Lesser General Public
25 License along with this library; if not, see <http://www.gnu.org/licenses/>.
28 #include "tdb_private.h"
30 /* all contexts, to ensure no double-opens (fcntl locks don't nest!) */
31 static struct tdb_context *tdbs = NULL;
33 /* We use two hashes to double-check they're using the right hash function. */
34 void tdb_header_hash(struct tdb_context *tdb,
35 uint32_t *magic1_hash, uint32_t *magic2_hash)
38 uint32_t tdb_magic = TDB_MAGIC;
40 hash_key.dptr = (unsigned char *)TDB_MAGIC_FOOD;
41 hash_key.dsize = sizeof(TDB_MAGIC_FOOD);
42 *magic1_hash = tdb->hash_fn(&hash_key);
44 hash_key.dptr = CONVERT(tdb_magic);
45 hash_key.dsize = sizeof(tdb_magic);
46 *magic2_hash = tdb->hash_fn(&hash_key);
48 /* Make sure at least one hash is non-zero! */
49 if (*magic1_hash == 0 && *magic2_hash == 0)
53 /* initialise a new database with a specified hash size */
54 static int tdb_new_database(struct tdb_context *tdb, int hash_size)
56 struct tdb_header *newdb;
61 /* We make it up in memory, then write it out if not internal */
62 size = sizeof(struct tdb_header) + (hash_size+1)*sizeof(tdb_off_t);
63 if (!(newdb = (struct tdb_header *)calloc(size, 1))) {
64 tdb->ecode = TDB_ERR_OOM;
68 /* Fill in the header */
69 newdb->version = TDB_VERSION;
70 newdb->hash_size = hash_size;
72 tdb_header_hash(tdb, &newdb->magic1_hash, &newdb->magic2_hash);
74 if (tdb->flags & TDB_INTERNAL) {
76 tdb->map_ptr = (char *)newdb;
77 memcpy(&tdb->header, newdb, sizeof(tdb->header));
78 /* Convert the `ondisk' version if asked. */
82 if (lseek(tdb->fd, 0, SEEK_SET) == -1)
85 if (ftruncate(tdb->fd, 0) == -1)
88 /* This creates an endian-converted header, as if read from disk */
90 memcpy(&tdb->header, newdb, sizeof(tdb->header));
91 /* Don't endian-convert the magic food! */
92 memcpy(newdb->magic_food, TDB_MAGIC_FOOD, strlen(TDB_MAGIC_FOOD)+1);
93 /* we still have "ret == -1" here */
94 written = write(tdb->fd, newdb, size);
95 if (written == size) {
97 } else if (written != -1) {
98 /* call write once again, this usually should return -1 and
99 * set errno appropriately */
101 written = write(tdb->fd, newdb+written, size);
102 if (written == size) {
104 } else if (written >= 0) {
105 /* a second incomplete write - we give up.
106 * guessing the errno... */
118 static int tdb_already_open(dev_t device,
121 struct tdb_context *i;
123 for (i = tdbs; i; i = i->next) {
124 if (i->device == device && i->inode == ino) {
132 /* open the database, creating it if necessary
134 The open_flags and mode are passed straight to the open call on the
135 database file. A flags value of O_WRONLY is invalid. The hash size
136 is advisory, use zero for a default value.
138 Return is NULL on error, in which case errno is also set. Don't
139 try to call tdb_error or tdb_errname, just do strerror(errno).
141 @param name may be NULL for internal databases. */
142 struct tdb_context *tdb_open(const char *name, int hash_size, int tdb_flags,
143 int open_flags, mode_t mode)
145 return tdb_open_ex(name, hash_size, tdb_flags, open_flags, mode, NULL, NULL);
148 /* a default logging function */
149 static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...) PRINTF_ATTRIBUTE(3, 4);
150 static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...)
155 struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
156 int open_flags, mode_t mode,
157 const struct tdb_logging_context *log_ctx,
158 tdb_hash_func hash_fn)
160 struct tdb_context *tdb;
162 int rev = 0, locked = 0;
166 uint32_t magic1_hash;
167 uint32_t magic2_hash;
168 const char *hash_alg;
170 if (!(tdb = (struct tdb_context *)calloc(1, sizeof *tdb))) {
182 tdb->flags = tdb_flags;
183 tdb->open_flags = open_flags;
187 tdb->log.log_fn = null_log_fn;
188 tdb->log.log_private = NULL;
192 tdb->hash_fn = hash_fn;
193 hash_alg = "user defined";
195 tdb->hash_fn = tdb_old_hash;
196 hash_alg = "default";
199 /* cache the page size */
200 tdb->page_size = getpagesize();
201 if (tdb->page_size <= 0) {
202 tdb->page_size = 0x2000;
205 tdb->max_dead_records = (tdb_flags & TDB_VOLATILE) ? 5 : 0;
207 if ((open_flags & O_ACCMODE) == O_WRONLY) {
208 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: can't open tdb %s write-only\n",
215 hash_size = DEFAULT_HASH_SIZE;
216 if ((open_flags & O_ACCMODE) == O_RDONLY) {
218 /* read only databases don't do locking or clear if first */
219 tdb->flags |= TDB_NOLOCK;
220 tdb->flags &= ~TDB_CLEAR_IF_FIRST;
223 if ((tdb->flags & TDB_ALLOW_NESTING) &&
224 (tdb->flags & TDB_DISALLOW_NESTING)) {
225 tdb->ecode = TDB_ERR_NESTING;
226 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
227 "allow_nesting and disallow_nesting are not allowed together!"));
233 * TDB_DISALLOW_NESTING is the default behavior.
235 if (!(tdb->flags & TDB_ALLOW_NESTING)) {
236 tdb->flags |= TDB_DISALLOW_NESTING;
239 /* internal databases don't mmap or lock, and start off cleared */
240 if (tdb->flags & TDB_INTERNAL) {
241 tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP);
242 tdb->flags &= ~TDB_CLEAR_IF_FIRST;
243 if (tdb_new_database(tdb, hash_size) != 0) {
244 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: tdb_new_database failed!"));
250 if ((tdb->fd = open(name, open_flags, mode)) == -1) {
251 TDB_LOG((tdb, TDB_DEBUG_WARNING, "tdb_open_ex: could not open file %s: %s\n",
252 name, strerror(errno)));
253 goto fail; /* errno set by open(2) */
256 /* on exec, don't inherit the fd */
257 v = fcntl(tdb->fd, F_GETFD, 0);
258 fcntl(tdb->fd, F_SETFD, v | FD_CLOEXEC);
260 /* ensure there is only one process initialising at once */
261 if (tdb_nest_lock(tdb, OPEN_LOCK, F_WRLCK, TDB_LOCK_WAIT) == -1) {
262 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to get open lock on %s: %s\n",
263 name, strerror(errno)));
264 goto fail; /* errno set by tdb_brlock */
267 /* we need to zero database if we are the only one with it open */
268 if ((tdb_flags & TDB_CLEAR_IF_FIRST) &&
270 (locked = (tdb_nest_lock(tdb, ACTIVE_LOCK, F_WRLCK, TDB_LOCK_NOWAIT|TDB_LOCK_PROBE) == 0))) {
271 open_flags |= O_CREAT;
272 if (ftruncate(tdb->fd, 0) == -1) {
273 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
274 "failed to truncate %s: %s\n",
275 name, strerror(errno)));
276 goto fail; /* errno set by ftruncate */
281 if (read(tdb->fd, &tdb->header, sizeof(tdb->header)) != sizeof(tdb->header)
282 || strcmp(tdb->header.magic_food, TDB_MAGIC_FOOD) != 0) {
283 if (!(open_flags & O_CREAT) || tdb_new_database(tdb, hash_size) == -1) {
285 errno = EIO; /* ie bad format or something */
289 rev = (tdb->flags & TDB_CONVERT);
290 } else if (tdb->header.version != TDB_VERSION
291 && !(rev = (tdb->header.version==TDB_BYTEREV(TDB_VERSION)))) {
296 vp = (unsigned char *)&tdb->header.version;
297 vertest = (((uint32_t)vp[0]) << 24) | (((uint32_t)vp[1]) << 16) |
298 (((uint32_t)vp[2]) << 8) | (uint32_t)vp[3];
299 tdb->flags |= (vertest==TDB_VERSION) ? TDB_BIGENDIAN : 0;
301 tdb->flags &= ~TDB_CONVERT;
303 tdb->flags |= TDB_CONVERT;
304 tdb_convert(&tdb->header, sizeof(tdb->header));
306 if (fstat(tdb->fd, &st) == -1)
309 if (tdb->header.rwlocks != 0) {
310 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: spinlocks no longer supported\n"));
314 tdb_header_hash(tdb, &magic1_hash, &magic2_hash);
316 if ((tdb->header.magic1_hash == 0) && (tdb->header.magic2_hash == 0)) {
317 /* older TDB without magic hash references */
318 } else if ((tdb->header.magic1_hash != magic1_hash) ||
319 (tdb->header.magic2_hash != magic2_hash)) {
320 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
321 "%s was not created with the %s hash function we are using\n"
322 "magic1_hash[0x%08X %s 0x%08X] "
323 "magic2_hash[0x%08X %s 0x%08X]\n",
325 tdb->header.magic1_hash,
326 (tdb->header.magic1_hash == magic1_hash) ? "==" : "!=",
328 tdb->header.magic2_hash,
329 (tdb->header.magic2_hash == magic2_hash) ? "==" : "!=",
335 /* Is it already in the open list? If so, fail. */
336 if (tdb_already_open(st.st_dev, st.st_ino)) {
337 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
338 "%s (%d,%d) is already open in this process\n",
339 name, (int)st.st_dev, (int)st.st_ino));
344 if (!(tdb->name = (char *)strdup(name))) {
349 tdb->map_size = st.st_size;
350 tdb->device = st.st_dev;
351 tdb->inode = st.st_ino;
354 if (tdb_nest_unlock(tdb, ACTIVE_LOCK, F_WRLCK, false) == -1) {
355 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
356 "failed to take ACTIVE_LOCK on %s: %s\n",
357 name, strerror(errno)));
363 /* We always need to do this if the CLEAR_IF_FIRST flag is set, even if
364 we didn't get the initial exclusive lock as we need to let all other
365 users know we're using it. */
367 if (tdb_flags & TDB_CLEAR_IF_FIRST) {
368 /* leave this lock in place to indicate it's in use */
369 if (tdb_nest_lock(tdb, ACTIVE_LOCK, F_RDLCK, TDB_LOCK_WAIT) == -1) {
374 /* if needed, run recovery */
375 if (tdb_transaction_recover(tdb) == -1) {
381 char tracefile[strlen(name) + 32];
383 snprintf(tracefile, sizeof(tracefile),
384 "%s.trace.%li", name, (long)getpid());
385 tdb->tracefd = open(tracefile, O_WRONLY|O_CREAT|O_EXCL, 0600);
386 if (tdb->tracefd >= 0) {
387 tdb_enable_seqnum(tdb);
388 tdb_trace_open(tdb, "tdb_open", hash_size, tdb_flags,
391 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to open trace file %s!\n", tracefile));
396 /* Internal (memory-only) databases skip all the code above to
397 * do with disk files, and resume here by releasing their
398 * open lock and hooking into the active list. */
399 if (tdb_nest_unlock(tdb, OPEN_LOCK, F_WRLCK, false) == -1) {
407 { int save_errno = errno;
416 if (tdb->flags & TDB_INTERNAL)
417 SAFE_FREE(tdb->map_ptr);
421 SAFE_FREE(tdb->name);
423 if (close(tdb->fd) != 0)
424 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to close tdb->fd on error!\n"));
425 SAFE_FREE(tdb->lockrecs);
433 * Set the maximum number of dead records per hash chain
436 void tdb_set_max_dead(struct tdb_context *tdb, int max_dead)
438 tdb->max_dead_records = max_dead;
444 * @returns -1 for error; 0 for success.
446 int tdb_close(struct tdb_context *tdb)
448 struct tdb_context **i;
451 if (tdb->transaction) {
452 tdb_transaction_cancel(tdb);
454 tdb_trace(tdb, "tdb_close");
457 if (tdb->flags & TDB_INTERNAL)
458 SAFE_FREE(tdb->map_ptr);
462 SAFE_FREE(tdb->name);
464 ret = close(tdb->fd);
467 SAFE_FREE(tdb->lockrecs);
469 /* Remove from contexts list */
470 for (i = &tdbs; *i; i = &(*i)->next) {
480 memset(tdb, 0, sizeof(*tdb));
486 /* register a loging function */
487 void tdb_set_logging_function(struct tdb_context *tdb,
488 const struct tdb_logging_context *log_ctx)
493 void *tdb_get_logging_private(struct tdb_context *tdb)
495 return tdb->log.log_private;
498 static int tdb_reopen_internal(struct tdb_context *tdb, bool active_lock)
502 if (tdb->flags & TDB_INTERNAL) {
503 return 0; /* Nothing to do. */
506 if (tdb_have_extra_locks(tdb)) {
507 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed with locks held\n"));
511 if (tdb->transaction != 0) {
512 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed inside a transaction\n"));
516 if (tdb_munmap(tdb) != 0) {
517 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: munmap failed (%s)\n", strerror(errno)));
520 if (close(tdb->fd) != 0)
521 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: WARNING closing tdb->fd failed!\n"));
522 tdb->fd = open(tdb->name, tdb->open_flags & ~(O_CREAT|O_TRUNC), 0);
524 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: open failed (%s)\n", strerror(errno)));
527 if (fstat(tdb->fd, &st) != 0) {
528 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: fstat failed (%s)\n", strerror(errno)));
531 if (st.st_ino != tdb->inode || st.st_dev != tdb->device) {
532 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: file dev/inode has changed!\n"));
537 /* We may still think we hold the active lock. */
538 tdb->num_lockrecs = 0;
539 SAFE_FREE(tdb->lockrecs);
541 if (active_lock && tdb_nest_lock(tdb, ACTIVE_LOCK, F_RDLCK, TDB_LOCK_WAIT) == -1) {
542 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: failed to obtain active lock\n"));
553 /* reopen a tdb - this can be used after a fork to ensure that we have an independent
554 seek pointer from our parent and to re-establish locks */
555 int tdb_reopen(struct tdb_context *tdb)
557 return tdb_reopen_internal(tdb, tdb->flags & TDB_CLEAR_IF_FIRST);
560 /* reopen all tdb's */
561 int tdb_reopen_all(int parent_longlived)
563 struct tdb_context *tdb;
565 for (tdb=tdbs; tdb; tdb = tdb->next) {
566 bool active_lock = (tdb->flags & TDB_CLEAR_IF_FIRST);
569 * If the parent is longlived (ie. a
570 * parent daemon architecture), we know
571 * it will keep it's active lock on a
572 * tdb opened with CLEAR_IF_FIRST. Thus
573 * for child processes we don't have to
574 * add an active lock. This is essential
575 * to improve performance on systems that
576 * keep POSIX locks as a non-scalable data
577 * structure in the kernel.
579 if (parent_longlived) {
580 /* Ensure no clear-if-first. */
584 if (tdb_reopen_internal(tdb, active_lock) != 0)