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;
34 /* This is based on the hash algorithm from gdbm */
35 static unsigned int default_tdb_hash(TDB_DATA *key)
37 uint32_t value; /* Used to compute the hash value. */
38 uint32_t i; /* Used to cycle through random values. */
40 /* Set the initial value from the key size. */
41 for (value = 0x238F13AF * key->dsize, i=0; i < key->dsize; i++)
42 value = (value + (key->dptr[i] << (i*5 % 24)));
44 return (1103515243 * value + 12345);
48 /* initialise a new database with a specified hash size */
49 static int tdb_new_database(struct tdb_context *tdb, int hash_size)
51 struct tdb_header *newdb;
57 /* We make it up in memory, then write it out if not internal */
58 size = sizeof(struct tdb_header) + (hash_size+1)*sizeof(tdb_off_t);
59 if (!(newdb = (struct tdb_header *)calloc(size, 1)))
60 return TDB_ERRCODE(TDB_ERR_OOM, -1);
62 /* Fill in the header */
63 newdb->version = TDB_VERSION;
64 newdb->hash_size = hash_size;
66 hash_key.dptr = discard_const_p(uint8_t, TDB_MAGIC_FOOD);
67 hash_key.dsize = sizeof(TDB_MAGIC_FOOD);
68 newdb->magic_food_hash = tdb->hash_fn(&hash_key);
70 hash_key.dptr = discard_const_p(uint8_t, TDB_MAGIC_HASH_VERIFY_KEY);
71 hash_key.dsize = sizeof(TDB_MAGIC_HASH_VERIFY_KEY);
72 newdb->verify_key_hash = tdb->hash_fn(&hash_key);
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;
167 uint32_t magic_food_hash;
168 uint32_t verify_key_hash;
169 const char *hash_alg;
171 if (!(tdb = (struct tdb_context *)calloc(1, sizeof *tdb))) {
180 tdb->flags = tdb_flags;
181 tdb->open_flags = open_flags;
185 tdb->log.log_fn = null_log_fn;
186 tdb->log.log_private = NULL;
190 tdb->hash_fn = hash_fn;
191 hash_alg = "user_defined";
193 tdb->hash_fn = default_tdb_hash;
194 hash_alg = "default";
197 /* cache the page size */
198 tdb->page_size = getpagesize();
199 if (tdb->page_size <= 0) {
200 tdb->page_size = 0x2000;
203 tdb->max_dead_records = (tdb_flags & TDB_VOLATILE) ? 5 : 0;
205 if ((open_flags & O_ACCMODE) == O_WRONLY) {
206 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: can't open tdb %s write-only\n",
213 hash_size = DEFAULT_HASH_SIZE;
214 if ((open_flags & O_ACCMODE) == O_RDONLY) {
216 /* read only databases don't do locking or clear if first */
217 tdb->flags |= TDB_NOLOCK;
218 tdb->flags &= ~TDB_CLEAR_IF_FIRST;
221 /* internal databases don't mmap or lock, and start off cleared */
222 if (tdb->flags & TDB_INTERNAL) {
223 tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP);
224 tdb->flags &= ~TDB_CLEAR_IF_FIRST;
225 if (tdb_new_database(tdb, hash_size) != 0) {
226 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: tdb_new_database failed!"));
232 if ((tdb->fd = open(name, open_flags, mode)) == -1) {
233 TDB_LOG((tdb, TDB_DEBUG_WARNING, "tdb_open_ex: could not open file %s: %s\n",
234 name, strerror(errno)));
235 goto fail; /* errno set by open(2) */
238 /* on exec, don't inherit the fd */
239 v = fcntl(tdb->fd, F_GETFD, 0);
240 fcntl(tdb->fd, F_SETFD, v | FD_CLOEXEC);
242 /* ensure there is only one process initialising at once */
243 if (tdb->methods->tdb_brlock(tdb, GLOBAL_LOCK, F_WRLCK, F_SETLKW, 0, 1) == -1) {
244 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to get global lock on %s: %s\n",
245 name, strerror(errno)));
246 goto fail; /* errno set by tdb_brlock */
249 /* we need to zero database if we are the only one with it open */
250 if ((tdb_flags & TDB_CLEAR_IF_FIRST) &&
252 (locked = (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_WRLCK, F_SETLK, 0, 1) == 0))) {
253 open_flags |= O_CREAT;
254 if (ftruncate(tdb->fd, 0) == -1) {
255 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
256 "failed to truncate %s: %s\n",
257 name, strerror(errno)));
258 goto fail; /* errno set by ftruncate */
263 if (read(tdb->fd, &tdb->header, sizeof(tdb->header)) != sizeof(tdb->header)
264 || strcmp(tdb->header.magic_food, TDB_MAGIC_FOOD) != 0
265 || (tdb->header.version != TDB_VERSION
266 && !(rev = (tdb->header.version==TDB_BYTEREV(TDB_VERSION))))) {
267 /* its not a valid database - possibly initialise it */
268 if (!(open_flags & O_CREAT) || tdb_new_database(tdb, hash_size) == -1) {
270 errno = EIO; /* ie bad format or something */
274 rev = (tdb->flags & TDB_CONVERT);
276 vp = (unsigned char *)&tdb->header.version;
277 vertest = (((uint32_t)vp[0]) << 24) | (((uint32_t)vp[1]) << 16) |
278 (((uint32_t)vp[2]) << 8) | (uint32_t)vp[3];
279 tdb->flags |= (vertest==TDB_VERSION) ? TDB_BIGENDIAN : 0;
281 tdb->flags &= ~TDB_CONVERT;
283 tdb->flags |= TDB_CONVERT;
284 tdb_convert(&tdb->header, sizeof(tdb->header));
286 if (fstat(tdb->fd, &st) == -1)
289 if (tdb->header.rwlocks != 0) {
290 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: spinlocks no longer supported\n"));
294 hash_key.dptr = discard_const_p(uint8_t, TDB_MAGIC_FOOD);
295 hash_key.dsize = sizeof(TDB_MAGIC_FOOD);
296 magic_food_hash = tdb->hash_fn(&hash_key);
298 hash_key.dptr = discard_const_p(uint8_t, TDB_MAGIC_HASH_VERIFY_KEY);
299 hash_key.dsize = sizeof(TDB_MAGIC_HASH_VERIFY_KEY);
300 verify_key_hash = tdb->hash_fn(&hash_key);
302 if ((tdb->header.magic_food_hash == 0) &&
303 (tdb->header.verify_key_hash == 0)) {
304 /* older TDB without magic hash references */
305 } else if ((tdb->header.magic_food_hash != magic_food_hash) ||
306 (tdb->header.verify_key_hash != verify_key_hash)) {
307 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: %s "
308 "was created with a different hash function current[%s]"
309 "magic_food_hash[0x%08X %s 0x%08X] "
310 "verify_key_hash[0x%08X %s 0x%08X]\n",
313 tdb->header.magic_food_hash,
314 (tdb->header.magic_food_hash == magic_food_hash)?"==":"!=",
316 tdb->header.verify_key_hash,
317 (tdb->header.verify_key_hash == verify_key_hash)?"==":"!=",
323 /* Is it already in the open list? If so, fail. */
324 if (tdb_already_open(st.st_dev, st.st_ino)) {
325 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
326 "%s (%d,%d) is already open in this process\n",
327 name, (int)st.st_dev, (int)st.st_ino));
332 if (!(tdb->name = (char *)strdup(name))) {
337 tdb->map_size = st.st_size;
338 tdb->device = st.st_dev;
339 tdb->inode = st.st_ino;
342 if (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_UNLCK, F_SETLK, 0, 1) == -1) {
343 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
344 "failed to take ACTIVE_LOCK on %s: %s\n",
345 name, strerror(errno)));
351 /* We always need to do this if the CLEAR_IF_FIRST flag is set, even if
352 we didn't get the initial exclusive lock as we need to let all other
353 users know we're using it. */
355 if (tdb_flags & TDB_CLEAR_IF_FIRST) {
356 /* leave this lock in place to indicate it's in use */
357 if (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_RDLCK, F_SETLKW, 0, 1) == -1)
361 /* if needed, run recovery */
362 if (tdb_transaction_recover(tdb) == -1) {
367 /* Internal (memory-only) databases skip all the code above to
368 * do with disk files, and resume here by releasing their
369 * global lock and hooking into the active list. */
370 if (tdb->methods->tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1) == -1)
377 { int save_errno = errno;
383 if (tdb->flags & TDB_INTERNAL)
384 SAFE_FREE(tdb->map_ptr);
388 SAFE_FREE(tdb->name);
390 if (close(tdb->fd) != 0)
391 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to close tdb->fd on error!\n"));
399 * Set the maximum number of dead records per hash chain
402 void tdb_set_max_dead(struct tdb_context *tdb, int max_dead)
404 tdb->max_dead_records = max_dead;
410 * @returns -1 for error; 0 for success.
412 int tdb_close(struct tdb_context *tdb)
414 struct tdb_context **i;
417 if (tdb->transaction) {
418 tdb_transaction_cancel(tdb);
422 if (tdb->flags & TDB_INTERNAL)
423 SAFE_FREE(tdb->map_ptr);
427 SAFE_FREE(tdb->name);
429 ret = close(tdb->fd);
430 SAFE_FREE(tdb->lockrecs);
432 /* Remove from contexts list */
433 for (i = &tdbs; *i; i = &(*i)->next) {
440 memset(tdb, 0, sizeof(*tdb));
446 /* register a loging function */
447 void tdb_set_logging_function(struct tdb_context *tdb,
448 const struct tdb_logging_context *log_ctx)
453 void *tdb_get_logging_private(struct tdb_context *tdb)
455 return tdb->log.log_private;
458 /* reopen a tdb - this can be used after a fork to ensure that we have an independent
459 seek pointer from our parent and to re-establish locks */
460 int tdb_reopen(struct tdb_context *tdb)
464 if (tdb->flags & TDB_INTERNAL) {
465 return 0; /* Nothing to do. */
468 if (tdb->num_locks != 0 || tdb->global_lock.count) {
469 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed with locks held\n"));
473 if (tdb->transaction != 0) {
474 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed inside a transaction\n"));
478 /* If we have real pread & pwrite, we can skip reopen. */
479 #if !defined(LIBREPLACE_PREAD_NOT_REPLACED) || \
480 !defined(LIBREPLACE_PWRITE_NOT_REPLACED)
481 if (tdb_munmap(tdb) != 0) {
482 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: munmap failed (%s)\n", strerror(errno)));
485 if (close(tdb->fd) != 0)
486 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: WARNING closing tdb->fd failed!\n"));
487 tdb->fd = open(tdb->name, tdb->open_flags & ~(O_CREAT|O_TRUNC), 0);
489 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: open failed (%s)\n", strerror(errno)));
492 if (fstat(tdb->fd, &st) != 0) {
493 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: fstat failed (%s)\n", strerror(errno)));
496 if (st.st_ino != tdb->inode || st.st_dev != tdb->device) {
497 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: file dev/inode has changed!\n"));
501 #endif /* fake pread or pwrite */
503 if ((tdb->flags & TDB_CLEAR_IF_FIRST) &&
504 (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_RDLCK, F_SETLKW, 0, 1) == -1)) {
505 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: failed to obtain active lock\n"));
516 /* reopen all tdb's */
517 int tdb_reopen_all(int parent_longlived)
519 struct tdb_context *tdb;
521 for (tdb=tdbs; tdb; tdb = tdb->next) {
523 * If the parent is longlived (ie. a
524 * parent daemon architecture), we know
525 * it will keep it's active lock on a
526 * tdb opened with CLEAR_IF_FIRST. Thus
527 * for child processes we don't have to
528 * add an active lock. This is essential
529 * to improve performance on systems that
530 * keep POSIX locks as a non-scalable data
531 * structure in the kernel.
533 if (parent_longlived) {
534 /* Ensure no clear-if-first. */
535 tdb->flags &= ~TDB_CLEAR_IF_FIRST;
538 if (tdb_reopen(tdb) != 0)