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;
56 /* We make it up in memory, then write it out if not internal */
57 size = sizeof(struct tdb_header) + (hash_size+1)*sizeof(tdb_off_t);
58 if (!(newdb = (struct tdb_header *)calloc(size, 1)))
59 return TDB_ERRCODE(TDB_ERR_OOM, -1);
61 /* Fill in the header */
62 newdb->version = TDB_VERSION;
63 newdb->hash_size = hash_size;
64 if (tdb->flags & TDB_INTERNAL) {
66 tdb->map_ptr = (char *)newdb;
67 memcpy(&tdb->header, newdb, sizeof(tdb->header));
68 /* Convert the `ondisk' version if asked. */
72 if (lseek(tdb->fd, 0, SEEK_SET) == -1)
75 if (ftruncate(tdb->fd, 0) == -1)
78 /* This creates an endian-converted header, as if read from disk */
80 memcpy(&tdb->header, newdb, sizeof(tdb->header));
81 /* Don't endian-convert the magic food! */
82 memcpy(newdb->magic_food, TDB_MAGIC_FOOD, strlen(TDB_MAGIC_FOOD)+1);
83 /* we still have "ret == -1" here */
84 written = write(tdb->fd, newdb, size);
85 if (written == size) {
87 } else if (written != -1) {
88 /* call write once again, this usually should return -1 and
89 * set errno appropriately */
91 written = write(tdb->fd, newdb+written, size);
92 if (written == size) {
94 } else if (written >= 0) {
95 /* a second incomplete write - we give up.
96 * guessing the errno... */
108 static int tdb_already_open(dev_t device,
111 struct tdb_context *i;
113 for (i = tdbs; i; i = i->next) {
114 if (i->device == device && i->inode == ino) {
122 /* open the database, creating it if necessary
124 The open_flags and mode are passed straight to the open call on the
125 database file. A flags value of O_WRONLY is invalid. The hash size
126 is advisory, use zero for a default value.
128 Return is NULL on error, in which case errno is also set. Don't
129 try to call tdb_error or tdb_errname, just do strerror(errno).
131 @param name may be NULL for internal databases. */
132 struct tdb_context *tdb_open(const char *name, int hash_size, int tdb_flags,
133 int open_flags, mode_t mode)
135 return tdb_open_ex(name, hash_size, tdb_flags, open_flags, mode, NULL, NULL);
138 /* a default logging function */
139 static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...) PRINTF_ATTRIBUTE(3, 4);
140 static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...)
145 struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
146 int open_flags, mode_t mode,
147 const struct tdb_logging_context *log_ctx,
148 tdb_hash_func hash_fn)
150 struct tdb_context *tdb;
152 int rev = 0, locked = 0;
157 char tracefile[strlen(name) + 32];
160 if (!(tdb = (struct tdb_context *)calloc(1, sizeof *tdb))) {
167 sprintf(tracefile, "%s.trace.%u", name, getpid());
168 tdb->tracefd = open(tracefile, O_WRONLY|O_CREAT|O_EXCL, 0600);
169 if (tdb->tracefd < 0)
171 tdb_trace(tdb, "tdb_open %s %u %#x %#x %p\n",
172 name, hash_size, tdb_flags, open_flags, hash_fn);
179 tdb->flags = tdb_flags;
180 tdb->open_flags = open_flags;
184 tdb->log.log_fn = null_log_fn;
185 tdb->log.log_private = NULL;
187 tdb->hash_fn = hash_fn ? hash_fn : default_tdb_hash;
189 /* cache the page size */
190 tdb->page_size = getpagesize();
191 if (tdb->page_size <= 0) {
192 tdb->page_size = 0x2000;
195 tdb->max_dead_records = (tdb_flags & TDB_VOLATILE) ? 5 : 0;
197 if ((open_flags & O_ACCMODE) == O_WRONLY) {
198 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: can't open tdb %s write-only\n",
205 hash_size = DEFAULT_HASH_SIZE;
206 if ((open_flags & O_ACCMODE) == O_RDONLY) {
208 /* read only databases don't do locking or clear if first */
209 tdb->flags |= TDB_NOLOCK;
210 tdb->flags &= ~TDB_CLEAR_IF_FIRST;
213 /* internal databases don't mmap or lock, and start off cleared */
214 if (tdb->flags & TDB_INTERNAL) {
215 tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP);
216 tdb->flags &= ~TDB_CLEAR_IF_FIRST;
217 if (tdb_new_database(tdb, hash_size) != 0) {
218 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: tdb_new_database failed!"));
224 if ((tdb->fd = open(name, open_flags, mode)) == -1) {
225 TDB_LOG((tdb, TDB_DEBUG_WARNING, "tdb_open_ex: could not open file %s: %s\n",
226 name, strerror(errno)));
227 goto fail; /* errno set by open(2) */
230 /* on exec, don't inherit the fd */
231 v = fcntl(tdb->fd, F_GETFD, 0);
232 fcntl(tdb->fd, F_SETFD, v | FD_CLOEXEC);
234 /* ensure there is only one process initialising at once */
235 if (tdb->methods->tdb_brlock(tdb, GLOBAL_LOCK, F_WRLCK, F_SETLKW, 0, 1) == -1) {
236 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to get global lock on %s: %s\n",
237 name, strerror(errno)));
238 goto fail; /* errno set by tdb_brlock */
241 /* we need to zero database if we are the only one with it open */
242 if ((tdb_flags & TDB_CLEAR_IF_FIRST) &&
244 (locked = (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_WRLCK, F_SETLK, 0, 1) == 0))) {
245 open_flags |= O_CREAT;
246 if (ftruncate(tdb->fd, 0) == -1) {
247 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
248 "failed to truncate %s: %s\n",
249 name, strerror(errno)));
250 goto fail; /* errno set by ftruncate */
255 if (read(tdb->fd, &tdb->header, sizeof(tdb->header)) != sizeof(tdb->header)
256 || strcmp(tdb->header.magic_food, TDB_MAGIC_FOOD) != 0
257 || (tdb->header.version != TDB_VERSION
258 && !(rev = (tdb->header.version==TDB_BYTEREV(TDB_VERSION))))) {
259 /* its not a valid database - possibly initialise it */
260 if (!(open_flags & O_CREAT) || tdb_new_database(tdb, hash_size) == -1) {
262 errno = EIO; /* ie bad format or something */
266 rev = (tdb->flags & TDB_CONVERT);
268 vp = (unsigned char *)&tdb->header.version;
269 vertest = (((uint32_t)vp[0]) << 24) | (((uint32_t)vp[1]) << 16) |
270 (((uint32_t)vp[2]) << 8) | (uint32_t)vp[3];
271 tdb->flags |= (vertest==TDB_VERSION) ? TDB_BIGENDIAN : 0;
273 tdb->flags &= ~TDB_CONVERT;
275 tdb->flags |= TDB_CONVERT;
276 tdb_convert(&tdb->header, sizeof(tdb->header));
278 if (fstat(tdb->fd, &st) == -1)
281 if (tdb->header.rwlocks != 0) {
282 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: spinlocks no longer supported\n"));
286 /* Is it already in the open list? If so, fail. */
287 if (tdb_already_open(st.st_dev, st.st_ino)) {
288 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
289 "%s (%d,%d) is already open in this process\n",
290 name, (int)st.st_dev, (int)st.st_ino));
295 if (!(tdb->name = (char *)strdup(name))) {
300 tdb->map_size = st.st_size;
301 tdb->device = st.st_dev;
302 tdb->inode = st.st_ino;
305 if (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_UNLCK, F_SETLK, 0, 1) == -1) {
306 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
307 "failed to take ACTIVE_LOCK on %s: %s\n",
308 name, strerror(errno)));
314 /* We always need to do this if the CLEAR_IF_FIRST flag is set, even if
315 we didn't get the initial exclusive lock as we need to let all other
316 users know we're using it. */
318 if (tdb_flags & TDB_CLEAR_IF_FIRST) {
319 /* leave this lock in place to indicate it's in use */
320 if (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_RDLCK, F_SETLKW, 0, 1) == -1)
324 /* if needed, run recovery */
325 if (tdb_transaction_recover(tdb) == -1) {
330 /* Internal (memory-only) databases skip all the code above to
331 * do with disk files, and resume here by releasing their
332 * global lock and hooking into the active list. */
333 if (tdb->methods->tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1) == -1)
340 { int save_errno = errno;
348 if (tdb->flags & TDB_INTERNAL)
349 SAFE_FREE(tdb->map_ptr);
353 SAFE_FREE(tdb->name);
355 if (close(tdb->fd) != 0)
356 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to close tdb->fd on error!\n"));
364 * Set the maximum number of dead records per hash chain
367 void tdb_set_max_dead(struct tdb_context *tdb, int max_dead)
369 tdb->max_dead_records = max_dead;
375 * @returns -1 for error; 0 for success.
377 int tdb_close(struct tdb_context *tdb)
379 struct tdb_context **i;
382 tdb_trace(tdb, "tdb_close\n");
383 if (tdb->transaction) {
384 tdb_transaction_cancel_internal(tdb);
388 if (tdb->flags & TDB_INTERNAL)
389 SAFE_FREE(tdb->map_ptr);
393 SAFE_FREE(tdb->name);
395 ret = close(tdb->fd);
396 SAFE_FREE(tdb->lockrecs);
398 /* Remove from contexts list */
399 for (i = &tdbs; *i; i = &(*i)->next) {
407 memset(tdb, 0, sizeof(*tdb));
413 /* register a loging function */
414 void tdb_set_logging_function(struct tdb_context *tdb,
415 const struct tdb_logging_context *log_ctx)
420 void *tdb_get_logging_private(struct tdb_context *tdb)
422 return tdb->log.log_private;
425 /* reopen a tdb - this can be used after a fork to ensure that we have an independent
426 seek pointer from our parent and to re-establish locks */
427 int tdb_reopen(struct tdb_context *tdb)
431 if (tdb->flags & TDB_INTERNAL) {
432 return 0; /* Nothing to do. */
435 if (tdb->num_locks != 0 || tdb->global_lock.count) {
436 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed with locks held\n"));
440 if (tdb->transaction != 0) {
441 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed inside a transaction\n"));
445 if (tdb_munmap(tdb) != 0) {
446 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: munmap failed (%s)\n", strerror(errno)));
449 if (close(tdb->fd) != 0)
450 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: WARNING closing tdb->fd failed!\n"));
451 tdb->fd = open(tdb->name, tdb->open_flags & ~(O_CREAT|O_TRUNC), 0);
453 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: open failed (%s)\n", strerror(errno)));
456 if ((tdb->flags & TDB_CLEAR_IF_FIRST) &&
457 (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_RDLCK, F_SETLKW, 0, 1) == -1)) {
458 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: failed to obtain active lock\n"));
461 if (fstat(tdb->fd, &st) != 0) {
462 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: fstat failed (%s)\n", strerror(errno)));
465 if (st.st_ino != tdb->inode || st.st_dev != tdb->device) {
466 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: file dev/inode has changed!\n"));
478 /* reopen all tdb's */
479 int tdb_reopen_all(int parent_longlived)
481 struct tdb_context *tdb;
483 for (tdb=tdbs; tdb; tdb = tdb->next) {
485 * If the parent is longlived (ie. a
486 * parent daemon architecture), we know
487 * it will keep it's active lock on a
488 * tdb opened with CLEAR_IF_FIRST. Thus
489 * for child processes we don't have to
490 * add an active lock. This is essential
491 * to improve performance on systems that
492 * keep POSIX locks as a non-scalable data
493 * structure in the kernel.
495 if (parent_longlived) {
496 /* Ensure no clear-if-first. */
497 tdb->flags &= ~TDB_CLEAR_IF_FIRST;
500 if (tdb_reopen(tdb) != 0)