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 u32 value
; /* Used to compute the hash value. */
38 u32 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
;
54 /* We make it up in memory, then write it out if not internal */
55 size
= sizeof(struct tdb_header
) + (hash_size
+1)*sizeof(tdb_off_t
);
56 if (!(newdb
= (struct tdb_header
*)calloc(size
, 1)))
57 return TDB_ERRCODE(TDB_ERR_OOM
, -1);
59 /* Fill in the header */
60 newdb
->version
= TDB_VERSION
;
61 newdb
->hash_size
= hash_size
;
62 if (tdb
->flags
& TDB_INTERNAL
) {
64 tdb
->map_ptr
= (char *)newdb
;
65 memcpy(&tdb
->header
, newdb
, sizeof(tdb
->header
));
66 /* Convert the `ondisk' version if asked. */
70 if (lseek(tdb
->fd
, 0, SEEK_SET
) == -1)
73 if (ftruncate(tdb
->fd
, 0) == -1)
76 /* This creates an endian-converted header, as if read from disk */
78 memcpy(&tdb
->header
, newdb
, sizeof(tdb
->header
));
79 /* Don't endian-convert the magic food! */
80 memcpy(newdb
->magic_food
, TDB_MAGIC_FOOD
, strlen(TDB_MAGIC_FOOD
)+1);
81 if (write(tdb
->fd
, newdb
, size
) != size
) {
94 static int tdb_already_open(dev_t device
,
97 struct tdb_context
*i
;
99 for (i
= tdbs
; i
; i
= i
->next
) {
100 if (i
->device
== device
&& i
->inode
== ino
) {
108 /* open the database, creating it if necessary
110 The open_flags and mode are passed straight to the open call on the
111 database file. A flags value of O_WRONLY is invalid. The hash size
112 is advisory, use zero for a default value.
114 Return is NULL on error, in which case errno is also set. Don't
115 try to call tdb_error or tdb_errname, just do strerror(errno).
117 @param name may be NULL for internal databases. */
118 struct tdb_context
*tdb_open(const char *name
, int hash_size
, int tdb_flags
,
119 int open_flags
, mode_t mode
)
121 return tdb_open_ex(name
, hash_size
, tdb_flags
, open_flags
, mode
, NULL
, NULL
);
124 /* a default logging function */
125 static void null_log_fn(struct tdb_context
*tdb
, enum tdb_debug_level level
, const char *fmt
, ...) PRINTF_ATTRIBUTE(3, 4);
126 static void null_log_fn(struct tdb_context
*tdb
, enum tdb_debug_level level
, const char *fmt
, ...)
131 struct tdb_context
*tdb_open_ex(const char *name
, int hash_size
, int tdb_flags
,
132 int open_flags
, mode_t mode
,
133 const struct tdb_logging_context
*log_ctx
,
134 tdb_hash_func hash_fn
)
136 struct tdb_context
*tdb
;
138 int rev
= 0, locked
= 0;
142 if (!(tdb
= (struct tdb_context
*)calloc(1, sizeof *tdb
))) {
151 tdb
->flags
= tdb_flags
;
152 tdb
->open_flags
= open_flags
;
156 tdb
->log
.log_fn
= null_log_fn
;
157 tdb
->log
.log_private
= NULL
;
159 tdb
->hash_fn
= hash_fn
? hash_fn
: default_tdb_hash
;
161 /* cache the page size */
162 tdb
->page_size
= getpagesize();
163 if (tdb
->page_size
<= 0) {
164 tdb
->page_size
= 0x2000;
167 if (open_flags
& TDB_VOLATILE
) {
168 tdb
->max_dead_records
= 5;
171 if ((open_flags
& O_ACCMODE
) == O_WRONLY
) {
172 TDB_LOG((tdb
, TDB_DEBUG_ERROR
, "tdb_open_ex: can't open tdb %s write-only\n",
179 hash_size
= DEFAULT_HASH_SIZE
;
180 if ((open_flags
& O_ACCMODE
) == O_RDONLY
) {
182 /* read only databases don't do locking or clear if first */
183 tdb
->flags
|= TDB_NOLOCK
;
184 tdb
->flags
&= ~TDB_CLEAR_IF_FIRST
;
187 /* internal databases don't mmap or lock, and start off cleared */
188 if (tdb
->flags
& TDB_INTERNAL
) {
189 tdb
->flags
|= (TDB_NOLOCK
| TDB_NOMMAP
);
190 tdb
->flags
&= ~TDB_CLEAR_IF_FIRST
;
191 if (tdb_new_database(tdb
, hash_size
) != 0) {
192 TDB_LOG((tdb
, TDB_DEBUG_ERROR
, "tdb_open_ex: tdb_new_database failed!"));
198 if ((tdb
->fd
= open(name
, open_flags
, mode
)) == -1) {
199 TDB_LOG((tdb
, TDB_DEBUG_WARNING
, "tdb_open_ex: could not open file %s: %s\n",
200 name
, strerror(errno
)));
201 goto fail
; /* errno set by open(2) */
204 /* ensure there is only one process initialising at once */
205 if (tdb
->methods
->tdb_brlock(tdb
, GLOBAL_LOCK
, F_WRLCK
, F_SETLKW
, 0, 1) == -1) {
206 TDB_LOG((tdb
, TDB_DEBUG_ERROR
, "tdb_open_ex: failed to get global lock on %s: %s\n",
207 name
, strerror(errno
)));
208 goto fail
; /* errno set by tdb_brlock */
211 /* we need to zero database if we are the only one with it open */
212 if ((tdb_flags
& TDB_CLEAR_IF_FIRST
) &&
213 (locked
= (tdb
->methods
->tdb_brlock(tdb
, ACTIVE_LOCK
, F_WRLCK
, F_SETLK
, 0, 1) == 0))) {
214 open_flags
|= O_CREAT
;
215 if (ftruncate(tdb
->fd
, 0) == -1) {
216 TDB_LOG((tdb
, TDB_DEBUG_FATAL
, "tdb_open_ex: "
217 "failed to truncate %s: %s\n",
218 name
, strerror(errno
)));
219 goto fail
; /* errno set by ftruncate */
223 if (read(tdb
->fd
, &tdb
->header
, sizeof(tdb
->header
)) != sizeof(tdb
->header
)
224 || strcmp(tdb
->header
.magic_food
, TDB_MAGIC_FOOD
) != 0
225 || (tdb
->header
.version
!= TDB_VERSION
226 && !(rev
= (tdb
->header
.version
==TDB_BYTEREV(TDB_VERSION
))))) {
227 /* its not a valid database - possibly initialise it */
228 if (!(open_flags
& O_CREAT
) || tdb_new_database(tdb
, hash_size
) == -1) {
229 errno
= EIO
; /* ie bad format or something */
232 rev
= (tdb
->flags
& TDB_CONVERT
);
234 vp
= (unsigned char *)&tdb
->header
.version
;
235 vertest
= (((u32
)vp
[0]) << 24) | (((u32
)vp
[1]) << 16) |
236 (((u32
)vp
[2]) << 8) | (u32
)vp
[3];
237 tdb
->flags
|= (vertest
==TDB_VERSION
) ? TDB_BIGENDIAN
: 0;
239 tdb
->flags
&= ~TDB_CONVERT
;
241 tdb
->flags
|= TDB_CONVERT
;
242 tdb_convert(&tdb
->header
, sizeof(tdb
->header
));
244 if (fstat(tdb
->fd
, &st
) == -1)
247 if (tdb
->header
.rwlocks
!= 0) {
248 TDB_LOG((tdb
, TDB_DEBUG_ERROR
, "tdb_open_ex: spinlocks no longer supported\n"));
252 /* Is it already in the open list? If so, fail. */
253 if (tdb_already_open(st
.st_dev
, st
.st_ino
)) {
254 TDB_LOG((tdb
, TDB_DEBUG_ERROR
, "tdb_open_ex: "
255 "%s (%d,%d) is already open in this process\n",
256 name
, (int)st
.st_dev
, (int)st
.st_ino
));
261 if (!(tdb
->name
= (char *)strdup(name
))) {
266 tdb
->map_size
= st
.st_size
;
267 tdb
->device
= st
.st_dev
;
268 tdb
->inode
= st
.st_ino
;
269 tdb
->max_dead_records
= 0;
272 if (tdb
->methods
->tdb_brlock(tdb
, ACTIVE_LOCK
, F_UNLCK
, F_SETLK
, 0, 1) == -1) {
273 TDB_LOG((tdb
, TDB_DEBUG_ERROR
, "tdb_open_ex: "
274 "failed to take ACTIVE_LOCK on %s: %s\n",
275 name
, strerror(errno
)));
281 /* We always need to do this if the CLEAR_IF_FIRST flag is set, even if
282 we didn't get the initial exclusive lock as we need to let all other
283 users know we're using it. */
285 if (tdb_flags
& TDB_CLEAR_IF_FIRST
) {
286 /* leave this lock in place to indicate it's in use */
287 if (tdb
->methods
->tdb_brlock(tdb
, ACTIVE_LOCK
, F_RDLCK
, F_SETLKW
, 0, 1) == -1)
291 /* if needed, run recovery */
292 if (tdb_transaction_recover(tdb
) == -1) {
297 /* Internal (memory-only) databases skip all the code above to
298 * do with disk files, and resume here by releasing their
299 * global lock and hooking into the active list. */
300 if (tdb
->methods
->tdb_brlock(tdb
, GLOBAL_LOCK
, F_UNLCK
, F_SETLKW
, 0, 1) == -1)
307 { int save_errno
= errno
;
313 if (tdb
->flags
& TDB_INTERNAL
)
314 SAFE_FREE(tdb
->map_ptr
);
318 SAFE_FREE(tdb
->name
);
320 if (close(tdb
->fd
) != 0)
321 TDB_LOG((tdb
, TDB_DEBUG_ERROR
, "tdb_open_ex: failed to close tdb->fd on error!\n"));
329 * Set the maximum number of dead records per hash chain
332 void tdb_set_max_dead(struct tdb_context
*tdb
, int max_dead
)
334 tdb
->max_dead_records
= max_dead
;
340 * @returns -1 for error; 0 for success.
342 int tdb_close(struct tdb_context
*tdb
)
344 struct tdb_context
**i
;
347 if (tdb
->transaction
) {
348 tdb_transaction_cancel(tdb
);
352 if (tdb
->flags
& TDB_INTERNAL
)
353 SAFE_FREE(tdb
->map_ptr
);
357 SAFE_FREE(tdb
->name
);
359 ret
= close(tdb
->fd
);
360 SAFE_FREE(tdb
->lockrecs
);
362 /* Remove from contexts list */
363 for (i
= &tdbs
; *i
; i
= &(*i
)->next
) {
370 memset(tdb
, 0, sizeof(*tdb
));
376 /* register a loging function */
377 void tdb_set_logging_function(struct tdb_context
*tdb
,
378 const struct tdb_logging_context
*log_ctx
)
383 void *tdb_get_logging_private(struct tdb_context
*tdb
)
385 return tdb
->log
.log_private
;
388 /* reopen a tdb - this can be used after a fork to ensure that we have an independent
389 seek pointer from our parent and to re-establish locks */
390 int tdb_reopen(struct tdb_context
*tdb
)
394 if (tdb
->flags
& TDB_INTERNAL
) {
395 return 0; /* Nothing to do. */
398 if (tdb
->num_locks
!= 0 || tdb
->global_lock
.count
) {
399 TDB_LOG((tdb
, TDB_DEBUG_ERROR
, "tdb_reopen: reopen not allowed with locks held\n"));
403 if (tdb
->transaction
!= 0) {
404 TDB_LOG((tdb
, TDB_DEBUG_ERROR
, "tdb_reopen: reopen not allowed inside a transaction\n"));
408 if (tdb_munmap(tdb
) != 0) {
409 TDB_LOG((tdb
, TDB_DEBUG_FATAL
, "tdb_reopen: munmap failed (%s)\n", strerror(errno
)));
412 if (close(tdb
->fd
) != 0)
413 TDB_LOG((tdb
, TDB_DEBUG_FATAL
, "tdb_reopen: WARNING closing tdb->fd failed!\n"));
414 tdb
->fd
= open(tdb
->name
, tdb
->open_flags
& ~(O_CREAT
|O_TRUNC
), 0);
416 TDB_LOG((tdb
, TDB_DEBUG_FATAL
, "tdb_reopen: open failed (%s)\n", strerror(errno
)));
419 if ((tdb
->flags
& TDB_CLEAR_IF_FIRST
) &&
420 (tdb
->methods
->tdb_brlock(tdb
, ACTIVE_LOCK
, F_RDLCK
, F_SETLKW
, 0, 1) == -1)) {
421 TDB_LOG((tdb
, TDB_DEBUG_FATAL
, "tdb_reopen: failed to obtain active lock\n"));
424 if (fstat(tdb
->fd
, &st
) != 0) {
425 TDB_LOG((tdb
, TDB_DEBUG_FATAL
, "tdb_reopen: fstat failed (%s)\n", strerror(errno
)));
428 if (st
.st_ino
!= tdb
->inode
|| st
.st_dev
!= tdb
->device
) {
429 TDB_LOG((tdb
, TDB_DEBUG_FATAL
, "tdb_reopen: file dev/inode has changed!\n"));
441 /* reopen all tdb's */
442 int tdb_reopen_all(int parent_longlived
)
444 struct tdb_context
*tdb
;
446 for (tdb
=tdbs
; tdb
; tdb
= tdb
->next
) {
448 * If the parent is longlived (ie. a
449 * parent daemon architecture), we know
450 * it will keep it's active lock on a
451 * tdb opened with CLEAR_IF_FIRST. Thus
452 * for child processes we don't have to
453 * add an active lock. This is essential
454 * to improve performance on systems that
455 * keep POSIX locks as a non-scalable data
456 * structure in the kernel.
458 if (parent_longlived
) {
459 /* Ensure no clear-if-first. */
460 tdb
->flags
&= ~TDB_CLEAR_IF_FIRST
;
463 if (tdb_reopen(tdb
) != 0)