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/>.
29 #include "tdb_private.h"
31 /* check for an out of bounds access - if it is out of bounds then
32 see if the database has been expanded by someone else and expand
34 note that "len" is the minimum length needed for the db
36 static int tdb_oob(struct tdb_context
*tdb
, tdb_off_t len
, int probe
)
39 if (len
<= tdb
->map_size
)
41 if (tdb
->flags
& TDB_INTERNAL
) {
43 /* Ensure ecode is set for log fn. */
44 tdb
->ecode
= TDB_ERR_IO
;
45 TDB_LOG((tdb
, TDB_DEBUG_FATAL
,"tdb_oob len %d beyond internal malloc size %d\n",
46 (int)len
, (int)tdb
->map_size
));
48 return TDB_ERRCODE(TDB_ERR_IO
, -1);
51 if (fstat(tdb
->fd
, &st
) == -1) {
52 return TDB_ERRCODE(TDB_ERR_IO
, -1);
55 if (st
.st_size
< (size_t)len
) {
57 /* Ensure ecode is set for log fn. */
58 tdb
->ecode
= TDB_ERR_IO
;
59 TDB_LOG((tdb
, TDB_DEBUG_FATAL
,"tdb_oob len %d beyond eof at %d\n",
60 (int)len
, (int)st
.st_size
));
62 return TDB_ERRCODE(TDB_ERR_IO
, -1);
65 /* Unmap, update size, remap */
66 if (tdb_munmap(tdb
) == -1)
67 return TDB_ERRCODE(TDB_ERR_IO
, -1);
68 tdb
->map_size
= st
.st_size
;
73 /* write a lump of data at a specified offset */
74 static int tdb_write(struct tdb_context
*tdb
, tdb_off_t off
,
75 const void *buf
, tdb_len_t len
)
81 if (tdb
->read_only
|| tdb
->traverse_read
) {
82 tdb
->ecode
= TDB_ERR_RDONLY
;
86 if (tdb
->methods
->tdb_oob(tdb
, off
+ len
, 0) != 0)
90 memcpy(off
+ (char *)tdb
->map_ptr
, buf
, len
);
92 ssize_t written
= pwrite(tdb
->fd
, buf
, len
, off
);
93 if ((written
!= (ssize_t
)len
) && (written
!= -1)) {
95 TDB_LOG((tdb
, TDB_DEBUG_FATAL
, "tdb_write: wrote only "
96 "%d of %d bytes at %d, trying once more\n",
97 (int)written
, len
, off
));
99 written
= pwrite(tdb
->fd
, (const void *)((const char *)buf
+written
),
104 /* Ensure ecode is set for log fn. */
105 tdb
->ecode
= TDB_ERR_IO
;
106 TDB_LOG((tdb
, TDB_DEBUG_FATAL
,"tdb_write failed at %d "
107 "len=%d (%s)\n", off
, len
, strerror(errno
)));
108 return TDB_ERRCODE(TDB_ERR_IO
, -1);
109 } else if (written
!= (ssize_t
)len
) {
110 TDB_LOG((tdb
, TDB_DEBUG_FATAL
, "tdb_write: failed to "
111 "write %d bytes at %d in two attempts\n",
114 return TDB_ERRCODE(TDB_ERR_IO
, -1);
120 /* Endian conversion: we only ever deal with 4 byte quantities */
121 void *tdb_convert(void *buf
, uint32_t size
)
123 uint32_t i
, *p
= (uint32_t *)buf
;
124 for (i
= 0; i
< size
/ 4; i
++)
125 p
[i
] = TDB_BYTEREV(p
[i
]);
130 /* read a lump of data at a specified offset, maybe convert */
131 static int tdb_read(struct tdb_context
*tdb
, tdb_off_t off
, void *buf
,
132 tdb_len_t len
, int cv
)
134 if (tdb
->methods
->tdb_oob(tdb
, off
+ len
, 0) != 0) {
139 memcpy(buf
, off
+ (char *)tdb
->map_ptr
, len
);
141 ssize_t ret
= pread(tdb
->fd
, buf
, len
, off
);
142 if (ret
!= (ssize_t
)len
) {
143 /* Ensure ecode is set for log fn. */
144 tdb
->ecode
= TDB_ERR_IO
;
145 TDB_LOG((tdb
, TDB_DEBUG_FATAL
,"tdb_read failed at %d "
146 "len=%d ret=%d (%s) map_size=%d\n",
147 (int)off
, (int)len
, (int)ret
, strerror(errno
),
148 (int)tdb
->map_size
));
149 return TDB_ERRCODE(TDB_ERR_IO
, -1);
153 tdb_convert(buf
, len
);
161 do an unlocked scan of the hash table heads to find the next non-zero head. The value
162 will then be confirmed with the lock held
164 static void tdb_next_hash_chain(struct tdb_context
*tdb
, uint32_t *chain
)
168 for (;h
< tdb
->header
.hash_size
;h
++) {
169 if (0 != *(uint32_t *)(TDB_HASH_TOP(h
) + (unsigned char *)tdb
->map_ptr
)) {
175 for (;h
< tdb
->header
.hash_size
;h
++) {
176 if (tdb_ofs_read(tdb
, TDB_HASH_TOP(h
), &off
) != 0 || off
!= 0) {
185 int tdb_munmap(struct tdb_context
*tdb
)
187 if (tdb
->flags
& TDB_INTERNAL
)
194 ret
= msync(tdb
->map_ptr
, tdb
->map_size
, MS_SYNC
);
198 ret
= munmap(tdb
->map_ptr
, tdb
->map_size
);
207 void tdb_mmap(struct tdb_context
*tdb
)
209 if (tdb
->flags
& TDB_INTERNAL
)
213 if (!(tdb
->flags
& TDB_NOMMAP
)) {
214 tdb
->map_ptr
= mmap(NULL
, tdb
->map_size
,
215 PROT_READ
|(tdb
->read_only
? 0:PROT_WRITE
),
216 MAP_SHARED
|MAP_FILE
, tdb
->fd
, 0);
219 * NB. When mmap fails it returns MAP_FAILED *NOT* NULL !!!!
222 if (tdb
->map_ptr
== MAP_FAILED
) {
224 TDB_LOG((tdb
, TDB_DEBUG_WARNING
, "tdb_mmap failed for size %d (%s)\n",
225 tdb
->map_size
, strerror(errno
)));
235 /* expand a file. we prefer to use ftruncate, as that is what posix
236 says to use for mmap expansion */
237 static int tdb_expand_file(struct tdb_context
*tdb
, tdb_off_t size
, tdb_off_t addition
)
241 if (tdb
->read_only
|| tdb
->traverse_read
) {
242 tdb
->ecode
= TDB_ERR_RDONLY
;
246 if (ftruncate(tdb
->fd
, size
+addition
) == -1) {
248 ssize_t written
= pwrite(tdb
->fd
, &b
, 1, (size
+addition
) - 1);
250 /* try once more, potentially revealing errno */
251 written
= pwrite(tdb
->fd
, &b
, 1, (size
+addition
) - 1);
254 /* again - give up, guessing errno */
258 TDB_LOG((tdb
, TDB_DEBUG_FATAL
, "expand_file to %d failed (%s)\n",
259 size
+addition
, strerror(errno
)));
264 /* now fill the file with something. This ensures that the
265 file isn't sparse, which would be very bad if we ran out of
266 disk. This must be done with write, not via mmap */
267 memset(buf
, TDB_PAD_BYTE
, sizeof(buf
));
269 size_t n
= addition
>sizeof(buf
)?sizeof(buf
):addition
;
270 ssize_t written
= pwrite(tdb
->fd
, buf
, n
, size
);
272 /* prevent infinite loops: try _once_ more */
273 written
= pwrite(tdb
->fd
, buf
, n
, size
);
276 /* give up, trying to provide a useful errno */
277 TDB_LOG((tdb
, TDB_DEBUG_FATAL
, "expand_file write "
278 "returned 0 twice: giving up!\n"));
281 } else if (written
== -1) {
282 TDB_LOG((tdb
, TDB_DEBUG_FATAL
, "expand_file write of "
283 "%d bytes failed (%s)\n", (int)n
,
286 } else if (written
!= n
) {
287 TDB_LOG((tdb
, TDB_DEBUG_WARNING
, "expand_file: wrote "
288 "only %d of %d bytes - retrying\n", (int)written
,
298 /* expand the database at least size bytes by expanding the underlying
299 file and doing the mmap again if necessary */
300 int tdb_expand(struct tdb_context
*tdb
, tdb_off_t size
)
302 struct list_struct rec
;
303 tdb_off_t offset
, new_size
;
305 if (tdb_lock(tdb
, -1, F_WRLCK
) == -1) {
306 TDB_LOG((tdb
, TDB_DEBUG_ERROR
, "lock failed in tdb_expand\n"));
310 /* must know about any previous expansions by another process */
311 tdb
->methods
->tdb_oob(tdb
, tdb
->map_size
+ 1, 1);
313 /* always make room for at least 100 more records, and at
314 least 25% more space. Round the database up to a multiple
316 new_size
= MAX(tdb
->map_size
+ size
*100, tdb
->map_size
* 1.25);
317 size
= TDB_ALIGN(new_size
, tdb
->page_size
) - tdb
->map_size
;
319 if (!(tdb
->flags
& TDB_INTERNAL
))
323 * We must ensure the file is unmapped before doing this
324 * to ensure consistency with systems like OpenBSD where
325 * writes and mmaps are not consistent.
328 /* expand the file itself */
329 if (!(tdb
->flags
& TDB_INTERNAL
)) {
330 if (tdb
->methods
->tdb_expand_file(tdb
, tdb
->map_size
, size
) != 0)
334 tdb
->map_size
+= size
;
336 if (tdb
->flags
& TDB_INTERNAL
) {
337 char *new_map_ptr
= (char *)realloc(tdb
->map_ptr
,
340 tdb
->map_size
-= size
;
343 tdb
->map_ptr
= new_map_ptr
;
346 * We must ensure the file is remapped before adding the space
347 * to ensure consistency with systems like OpenBSD where
348 * writes and mmaps are not consistent.
351 /* We're ok if the mmap fails as we'll fallback to read/write */
355 /* form a new freelist record */
356 memset(&rec
,'\0',sizeof(rec
));
357 rec
.rec_len
= size
- sizeof(rec
);
359 /* link it into the free list */
360 offset
= tdb
->map_size
- size
;
361 if (tdb_free(tdb
, offset
, &rec
) == -1)
364 tdb_unlock(tdb
, -1, F_WRLCK
);
367 tdb_unlock(tdb
, -1, F_WRLCK
);
371 /* read/write a tdb_off_t */
372 int tdb_ofs_read(struct tdb_context
*tdb
, tdb_off_t offset
, tdb_off_t
*d
)
374 return tdb
->methods
->tdb_read(tdb
, offset
, (char*)d
, sizeof(*d
), DOCONV());
377 int tdb_ofs_write(struct tdb_context
*tdb
, tdb_off_t offset
, tdb_off_t
*d
)
380 return tdb
->methods
->tdb_write(tdb
, offset
, CONVERT(off
), sizeof(*d
));
384 /* read a lump of data, allocating the space for it */
385 unsigned char *tdb_alloc_read(struct tdb_context
*tdb
, tdb_off_t offset
, tdb_len_t len
)
389 /* some systems don't like zero length malloc */
394 if (!(buf
= (unsigned char *)malloc(len
))) {
395 /* Ensure ecode is set for log fn. */
396 tdb
->ecode
= TDB_ERR_OOM
;
397 TDB_LOG((tdb
, TDB_DEBUG_ERROR
,"tdb_alloc_read malloc failed len=%d (%s)\n",
398 len
, strerror(errno
)));
399 return TDB_ERRCODE(TDB_ERR_OOM
, buf
);
401 if (tdb
->methods
->tdb_read(tdb
, offset
, buf
, len
, 0) == -1) {
408 /* Give a piece of tdb data to a parser */
410 int tdb_parse_data(struct tdb_context
*tdb
, TDB_DATA key
,
411 tdb_off_t offset
, tdb_len_t len
,
412 int (*parser
)(TDB_DATA key
, TDB_DATA data
,
421 if ((tdb
->transaction
== NULL
) && (tdb
->map_ptr
!= NULL
)) {
423 * Optimize by avoiding the malloc/memcpy/free, point the
424 * parser directly at the mmap area.
426 if (tdb
->methods
->tdb_oob(tdb
, offset
+len
, 0) != 0) {
429 data
.dptr
= offset
+ (unsigned char *)tdb
->map_ptr
;
430 return parser(key
, data
, private_data
);
433 if (!(data
.dptr
= tdb_alloc_read(tdb
, offset
, len
))) {
437 result
= parser(key
, data
, private_data
);
442 /* read/write a record */
443 int tdb_rec_read(struct tdb_context
*tdb
, tdb_off_t offset
, struct list_struct
*rec
)
445 if (tdb
->methods
->tdb_read(tdb
, offset
, rec
, sizeof(*rec
),DOCONV()) == -1)
447 if (TDB_BAD_MAGIC(rec
)) {
448 /* Ensure ecode is set for log fn. */
449 tdb
->ecode
= TDB_ERR_CORRUPT
;
450 TDB_LOG((tdb
, TDB_DEBUG_FATAL
,"tdb_rec_read bad magic 0x%x at offset=%d\n", rec
->magic
, offset
));
451 return TDB_ERRCODE(TDB_ERR_CORRUPT
, -1);
453 return tdb
->methods
->tdb_oob(tdb
, rec
->next
+sizeof(*rec
), 0);
456 int tdb_rec_write(struct tdb_context
*tdb
, tdb_off_t offset
, struct list_struct
*rec
)
458 struct list_struct r
= *rec
;
459 return tdb
->methods
->tdb_write(tdb
, offset
, CONVERT(r
), sizeof(r
));
462 static const struct tdb_methods io_methods
= {
472 initialise the default methods table
474 void tdb_io_init(struct tdb_context
*tdb
)
476 tdb
->methods
= &io_methods
;