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;
156 if (!(tdb = (struct tdb_context *)calloc(1, sizeof *tdb))) {
165 tdb->flags = tdb_flags;
166 tdb->open_flags = open_flags;
170 tdb->log.log_fn = null_log_fn;
171 tdb->log.log_private = NULL;
173 tdb->hash_fn = hash_fn ? hash_fn : default_tdb_hash;
175 /* cache the page size */
176 tdb->page_size = getpagesize();
177 if (tdb->page_size <= 0) {
178 tdb->page_size = 0x2000;
181 if (open_flags & TDB_VOLATILE) {
182 tdb->max_dead_records = 5;
185 if ((open_flags & O_ACCMODE) == O_WRONLY) {
186 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: can't open tdb %s write-only\n",
193 hash_size = DEFAULT_HASH_SIZE;
194 if ((open_flags & O_ACCMODE) == O_RDONLY) {
196 /* read only databases don't do locking or clear if first */
197 tdb->flags |= TDB_NOLOCK;
198 tdb->flags &= ~TDB_CLEAR_IF_FIRST;
201 /* internal databases don't mmap or lock, and start off cleared */
202 if (tdb->flags & TDB_INTERNAL) {
203 tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP);
204 tdb->flags &= ~TDB_CLEAR_IF_FIRST;
205 if (tdb_new_database(tdb, hash_size) != 0) {
206 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: tdb_new_database failed!"));
212 if ((tdb->fd = open(name, open_flags, mode)) == -1) {
213 TDB_LOG((tdb, TDB_DEBUG_WARNING, "tdb_open_ex: could not open file %s: %s\n",
214 name, strerror(errno)));
215 goto fail; /* errno set by open(2) */
218 /* ensure there is only one process initialising at once */
219 if (tdb->methods->tdb_brlock(tdb, GLOBAL_LOCK, F_WRLCK, F_SETLKW, 0, 1) == -1) {
220 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to get global lock on %s: %s\n",
221 name, strerror(errno)));
222 goto fail; /* errno set by tdb_brlock */
225 /* we need to zero database if we are the only one with it open */
226 if ((tdb_flags & TDB_CLEAR_IF_FIRST) &&
227 (locked = (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_WRLCK, F_SETLK, 0, 1) == 0))) {
228 open_flags |= O_CREAT;
229 if (ftruncate(tdb->fd, 0) == -1) {
230 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
231 "failed to truncate %s: %s\n",
232 name, strerror(errno)));
233 goto fail; /* errno set by ftruncate */
238 if (read(tdb->fd, &tdb->header, sizeof(tdb->header)) != sizeof(tdb->header)
239 || strcmp(tdb->header.magic_food, TDB_MAGIC_FOOD) != 0
240 || (tdb->header.version != TDB_VERSION
241 && !(rev = (tdb->header.version==TDB_BYTEREV(TDB_VERSION))))) {
242 /* its not a valid database - possibly initialise it */
243 if (!(open_flags & O_CREAT) || tdb_new_database(tdb, hash_size) == -1) {
245 errno = EIO; /* ie bad format or something */
249 rev = (tdb->flags & TDB_CONVERT);
251 vp = (unsigned char *)&tdb->header.version;
252 vertest = (((uint32_t)vp[0]) << 24) | (((uint32_t)vp[1]) << 16) |
253 (((uint32_t)vp[2]) << 8) | (uint32_t)vp[3];
254 tdb->flags |= (vertest==TDB_VERSION) ? TDB_BIGENDIAN : 0;
256 tdb->flags &= ~TDB_CONVERT;
258 tdb->flags |= TDB_CONVERT;
259 tdb_convert(&tdb->header, sizeof(tdb->header));
261 if (fstat(tdb->fd, &st) == -1)
264 if (tdb->header.rwlocks != 0) {
265 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: spinlocks no longer supported\n"));
269 /* Is it already in the open list? If so, fail. */
270 if (tdb_already_open(st.st_dev, st.st_ino)) {
271 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
272 "%s (%d,%d) is already open in this process\n",
273 name, (int)st.st_dev, (int)st.st_ino));
278 if (!(tdb->name = (char *)strdup(name))) {
283 tdb->map_size = st.st_size;
284 tdb->device = st.st_dev;
285 tdb->inode = st.st_ino;
286 tdb->max_dead_records = 0;
289 if (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_UNLCK, F_SETLK, 0, 1) == -1) {
290 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
291 "failed to take ACTIVE_LOCK on %s: %s\n",
292 name, strerror(errno)));
298 /* We always need to do this if the CLEAR_IF_FIRST flag is set, even if
299 we didn't get the initial exclusive lock as we need to let all other
300 users know we're using it. */
302 if (tdb_flags & TDB_CLEAR_IF_FIRST) {
303 /* leave this lock in place to indicate it's in use */
304 if (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_RDLCK, F_SETLKW, 0, 1) == -1)
308 /* if needed, run recovery */
309 if (tdb_transaction_recover(tdb) == -1) {
314 /* Internal (memory-only) databases skip all the code above to
315 * do with disk files, and resume here by releasing their
316 * global lock and hooking into the active list. */
317 if (tdb->methods->tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1) == -1)
324 { int save_errno = errno;
330 if (tdb->flags & TDB_INTERNAL)
331 SAFE_FREE(tdb->map_ptr);
335 SAFE_FREE(tdb->name);
337 if (close(tdb->fd) != 0)
338 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to close tdb->fd on error!\n"));
346 * Set the maximum number of dead records per hash chain
349 void tdb_set_max_dead(struct tdb_context *tdb, int max_dead)
351 tdb->max_dead_records = max_dead;
357 * @returns -1 for error; 0 for success.
359 int tdb_close(struct tdb_context *tdb)
361 struct tdb_context **i;
364 if (tdb->transaction) {
365 tdb_transaction_cancel(tdb);
369 if (tdb->flags & TDB_INTERNAL)
370 SAFE_FREE(tdb->map_ptr);
374 SAFE_FREE(tdb->name);
376 ret = close(tdb->fd);
377 SAFE_FREE(tdb->lockrecs);
379 /* Remove from contexts list */
380 for (i = &tdbs; *i; i = &(*i)->next) {
387 memset(tdb, 0, sizeof(*tdb));
393 /* register a loging function */
394 void tdb_set_logging_function(struct tdb_context *tdb,
395 const struct tdb_logging_context *log_ctx)
400 void *tdb_get_logging_private(struct tdb_context *tdb)
402 return tdb->log.log_private;
405 /* reopen a tdb - this can be used after a fork to ensure that we have an independent
406 seek pointer from our parent and to re-establish locks */
407 int tdb_reopen(struct tdb_context *tdb)
411 if (tdb->flags & TDB_INTERNAL) {
412 return 0; /* Nothing to do. */
415 if (tdb->num_locks != 0 || tdb->global_lock.count) {
416 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed with locks held\n"));
420 if (tdb->transaction != 0) {
421 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed inside a transaction\n"));
425 if (tdb_munmap(tdb) != 0) {
426 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: munmap failed (%s)\n", strerror(errno)));
429 if (close(tdb->fd) != 0)
430 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: WARNING closing tdb->fd failed!\n"));
431 tdb->fd = open(tdb->name, tdb->open_flags & ~(O_CREAT|O_TRUNC), 0);
433 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: open failed (%s)\n", strerror(errno)));
436 if ((tdb->flags & TDB_CLEAR_IF_FIRST) &&
437 (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_RDLCK, F_SETLKW, 0, 1) == -1)) {
438 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: failed to obtain active lock\n"));
441 if (fstat(tdb->fd, &st) != 0) {
442 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: fstat failed (%s)\n", strerror(errno)));
445 if (st.st_ino != tdb->inode || st.st_dev != tdb->device) {
446 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: file dev/inode has changed!\n"));
458 /* reopen all tdb's */
459 int tdb_reopen_all(int parent_longlived)
461 struct tdb_context *tdb;
463 for (tdb=tdbs; tdb; tdb = tdb->next) {
465 * If the parent is longlived (ie. a
466 * parent daemon architecture), we know
467 * it will keep it's active lock on a
468 * tdb opened with CLEAR_IF_FIRST. Thus
469 * for child processes we don't have to
470 * add an active lock. This is essential
471 * to improve performance on systems that
472 * keep POSIX locks as a non-scalable data
473 * structure in the kernel.
475 if (parent_longlived) {
476 /* Ensure no clear-if-first. */
477 tdb->flags &= ~TDB_CLEAR_IF_FIRST;
480 if (tdb_reopen(tdb) != 0)