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 "tdb1_private.h"
31 #define MAX(a,b) ((a) > (b) ? (a) : (b))
34 /* check for an out of bounds access - if it is out of bounds then
35 see if the database has been expanded by someone else and expand
37 note that "len" is the minimum length needed for the db
39 static int tdb1_oob(struct tdb1_context *tdb, tdb1_off_t len, int probe)
42 if (len <= tdb->file->map_size)
44 if (tdb->flags & TDB_INTERNAL) {
46 tdb->last_error = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
47 "tdb1_oob len %d beyond internal malloc size %d",
48 (int)len, (int)tdb->file->map_size);
53 if (fstat(tdb->file->fd, &st) == -1) {
54 tdb->last_error = TDB_ERR_IO;
58 if (st.st_size < (size_t)len) {
60 tdb->last_error = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
61 "tdb1_oob len %d beyond eof at %d",
62 (int)len, (int)st.st_size);
67 /* Unmap, update size, remap */
68 if (tdb1_munmap(tdb) == -1) {
69 tdb->last_error = TDB_ERR_IO;
72 tdb->file->map_size = st.st_size;
77 /* write a lump of data at a specified offset */
78 static int tdb1_write(struct tdb1_context *tdb, tdb1_off_t off,
79 const void *buf, tdb1_len_t len)
85 if (tdb->read_only || tdb->traverse_read) {
86 tdb->last_error = TDB_ERR_RDONLY;
90 if (tdb->methods->tdb1_oob(tdb, off + len, 0) != 0)
93 if (tdb->file->map_ptr) {
94 memcpy(off + (char *)tdb->file->map_ptr, buf, len);
96 ssize_t written = pwrite(tdb->file->fd, buf, len, off);
97 if ((written != (ssize_t)len) && (written != -1)) {
98 tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_WARNING,
99 "tdb1_write: wrote only "
100 "%d of %d bytes at %d, trying once more",
101 (int)written, len, off);
102 written = pwrite(tdb->file->fd,
103 (const char *)buf+written,
108 /* Ensure ecode is set for log fn. */
109 tdb->last_error = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
110 "tdb1_write failed at %d "
112 off, len, strerror(errno));
114 } else if (written != (ssize_t)len) {
115 tdb->last_error = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
116 "tdb1_write: failed to "
117 "write %d bytes at %d in two attempts",
125 /* Endian conversion: we only ever deal with 4 byte quantities */
126 void *tdb1_convert(void *buf, uint32_t size)
128 uint32_t i, *p = (uint32_t *)buf;
129 for (i = 0; i < size / 4; i++)
130 p[i] = TDB1_BYTEREV(p[i]);
135 /* read a lump of data at a specified offset, maybe convert */
136 static int tdb1_read(struct tdb1_context *tdb, tdb1_off_t off, void *buf,
137 tdb1_len_t len, int cv)
139 if (tdb->methods->tdb1_oob(tdb, off + len, 0) != 0) {
143 if (tdb->file->map_ptr) {
144 memcpy(buf, off + (char *)tdb->file->map_ptr, len);
146 ssize_t ret = pread(tdb->file->fd, buf, len, off);
147 if (ret != (ssize_t)len) {
148 /* Ensure ecode is set for log fn. */
149 tdb->last_error = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
150 "tdb1_read failed at %d "
151 "len=%d ret=%d (%s) map_size=%d",
152 (int)off, (int)len, (int)ret,
154 (int)tdb->file->map_size);
159 tdb1_convert(buf, len);
167 do an unlocked scan of the hash table heads to find the next non-zero head. The value
168 will then be confirmed with the lock held
170 static void tdb1_next_hash_chain(struct tdb1_context *tdb, uint32_t *chain)
173 if (tdb->file->map_ptr) {
174 for (;h < tdb->header.hash_size;h++) {
175 if (0 != *(uint32_t *)(TDB1_HASH_TOP(h) + (unsigned char *)tdb->file->map_ptr)) {
181 for (;h < tdb->header.hash_size;h++) {
182 if (tdb1_ofs_read(tdb, TDB1_HASH_TOP(h), &off) != 0 || off != 0) {
191 int tdb1_munmap(struct tdb1_context *tdb)
193 if (tdb->flags & TDB_INTERNAL)
197 if (tdb->file->map_ptr) {
200 ret = munmap(tdb->file->map_ptr, tdb->file->map_size);
205 tdb->file->map_ptr = NULL;
209 void tdb1_mmap(struct tdb1_context *tdb)
211 if (tdb->flags & TDB_INTERNAL)
215 if (!(tdb->flags & TDB_NOMMAP)) {
216 tdb->file->map_ptr = mmap(NULL, tdb->file->map_size,
217 PROT_READ|(tdb->read_only? 0:PROT_WRITE),
218 MAP_SHARED|MAP_FILE, tdb->file->fd, 0);
221 * NB. When mmap fails it returns MAP_FAILED *NOT* NULL !!!!
224 if (tdb->file->map_ptr == MAP_FAILED) {
225 tdb->file->map_ptr = NULL;
226 tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_WARNING,
227 "tdb1_mmap failed for size %d (%s)",
228 tdb->file->map_size, strerror(errno));
231 tdb->file->map_ptr = NULL;
234 tdb->file->map_ptr = NULL;
238 /* expand a file. we prefer to use ftruncate, as that is what posix
239 says to use for mmap expansion */
240 static int tdb1_expand_file(struct tdb1_context *tdb, tdb1_off_t size, tdb1_off_t addition)
244 if (tdb->read_only || tdb->traverse_read) {
245 tdb->last_error = TDB_ERR_RDONLY;
249 if (ftruncate(tdb->file->fd, size+addition) == -1) {
251 ssize_t written = pwrite(tdb->file->fd, &b, 1,
252 (size+addition) - 1);
254 /* try once more, potentially revealing errno */
255 written = pwrite(tdb->file->fd, &b, 1,
256 (size+addition) - 1);
259 /* again - give up, guessing errno */
263 tdb->last_error = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
264 "expand_file to %d failed (%s)",
271 /* now fill the file with something. This ensures that the
272 file isn't sparse, which would be very bad if we ran out of
273 disk. This must be done with write, not via mmap */
274 memset(buf, TDB1_PAD_BYTE, sizeof(buf));
276 size_t n = addition>sizeof(buf)?sizeof(buf):addition;
277 ssize_t written = pwrite(tdb->file->fd, buf, n, size);
279 /* prevent infinite loops: try _once_ more */
280 written = pwrite(tdb->file->fd, buf, n, size);
283 /* give up, trying to provide a useful errno */
284 tdb->last_error = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
286 "returned 0 twice: giving up!");
289 } else if (written == -1) {
290 tdb->last_error = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
291 "expand_file write of "
292 "%d bytes failed (%s)", (int)n,
295 } else if (written != n) {
296 tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_WARNING,
297 "expand_file: wrote "
298 "only %d of %d bytes - retrying",
299 (int)written, (int)n);
308 /* expand the database at least size bytes by expanding the underlying
309 file and doing the mmap again if necessary */
310 int tdb1_expand(struct tdb1_context *tdb, tdb1_off_t size)
312 struct tdb1_record rec;
313 tdb1_off_t offset, new_size, top_size, map_size;
315 if (tdb1_lock(tdb, -1, F_WRLCK) == -1) {
316 tdb_logerr(tdb, tdb->last_error, TDB_LOG_ERROR,
317 "lock failed in tdb1_expand");
321 /* must know about any previous expansions by another process */
322 tdb->methods->tdb1_oob(tdb, tdb->file->map_size + 1, 1);
324 /* limit size in order to avoid using up huge amounts of memory for
325 * in memory tdbs if an oddball huge record creeps in */
326 if (size > 100 * 1024) {
327 top_size = tdb->file->map_size + size * 2;
329 top_size = tdb->file->map_size + size * 100;
332 /* always make room for at least top_size more records, and at
333 least 25% more space. if the DB is smaller than 100MiB,
334 otherwise grow it by 10% only. */
335 if (tdb->file->map_size > 100 * 1024 * 1024) {
336 map_size = tdb->file->map_size * 1.10;
338 map_size = tdb->file->map_size * 1.25;
341 /* Round the database up to a multiple of the page size */
342 new_size = MAX(top_size, map_size);
343 size = TDB1_ALIGN(new_size, tdb->page_size) - tdb->file->map_size;
345 if (!(tdb->flags & TDB_INTERNAL))
349 * We must ensure the file is unmapped before doing this
350 * to ensure consistency with systems like OpenBSD where
351 * writes and mmaps are not consistent.
354 /* expand the file itself */
355 if (!(tdb->flags & TDB_INTERNAL)) {
356 if (tdb->methods->tdb1_expand_file(tdb, tdb->file->map_size, size) != 0)
360 tdb->file->map_size += size;
362 if (tdb->flags & TDB_INTERNAL) {
363 char *new_map_ptr = (char *)realloc(tdb->file->map_ptr,
364 tdb->file->map_size);
366 tdb->file->map_size -= size;
369 tdb->file->map_ptr = new_map_ptr;
372 * We must ensure the file is remapped before adding the space
373 * to ensure consistency with systems like OpenBSD where
374 * writes and mmaps are not consistent.
377 /* We're ok if the mmap fails as we'll fallback to read/write */
381 /* form a new freelist record */
382 memset(&rec,'\0',sizeof(rec));
383 rec.rec_len = size - sizeof(rec);
385 /* link it into the free list */
386 offset = tdb->file->map_size - size;
387 if (tdb1_free(tdb, offset, &rec) == -1)
390 tdb1_unlock(tdb, -1, F_WRLCK);
393 tdb1_unlock(tdb, -1, F_WRLCK);
397 /* read/write a tdb1_off_t */
398 int tdb1_ofs_read(struct tdb1_context *tdb, tdb1_off_t offset, tdb1_off_t *d)
400 return tdb->methods->tdb1_read(tdb, offset, (char*)d, sizeof(*d), TDB1_DOCONV());
403 int tdb1_ofs_write(struct tdb1_context *tdb, tdb1_off_t offset, tdb1_off_t *d)
406 return tdb->methods->tdb1_write(tdb, offset, TDB1_CONV(off), sizeof(*d));
410 /* read a lump of data, allocating the space for it */
411 unsigned char *tdb1_alloc_read(struct tdb1_context *tdb, tdb1_off_t offset, tdb1_len_t len)
415 /* some systems don't like zero length malloc */
417 if (!(buf = (unsigned char *)malloc(len ? len : 1))) {
418 tdb->last_error = tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
419 "tdb1_alloc_read malloc failed"
421 len, strerror(errno));
424 if (tdb->methods->tdb1_read(tdb, offset, buf, len, 0) == -1) {
431 /* Give a piece of tdb data to a parser */
433 int tdb1_parse_data(struct tdb1_context *tdb, TDB_DATA key,
434 tdb1_off_t offset, tdb1_len_t len,
435 int (*parser)(TDB_DATA key, TDB_DATA data,
444 if ((tdb->transaction == NULL) && (tdb->file->map_ptr != NULL)) {
446 * Optimize by avoiding the malloc/memcpy/free, point the
447 * parser directly at the mmap area.
449 if (tdb->methods->tdb1_oob(tdb, offset+len, 0) != 0) {
452 data.dptr = offset + (unsigned char *)tdb->file->map_ptr;
453 return parser(key, data, private_data);
456 if (!(data.dptr = tdb1_alloc_read(tdb, offset, len))) {
460 result = parser(key, data, private_data);
465 /* read/write a record */
466 int tdb1_rec_read(struct tdb1_context *tdb, tdb1_off_t offset, struct tdb1_record *rec)
468 if (tdb->methods->tdb1_read(tdb, offset, rec, sizeof(*rec),TDB1_DOCONV()) == -1)
470 if (TDB1_BAD_MAGIC(rec)) {
471 tdb->last_error = tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
472 "tdb1_rec_read bad magic 0x%x at offset=%d",
476 return tdb->methods->tdb1_oob(tdb, rec->next+sizeof(*rec), 0);
479 int tdb1_rec_write(struct tdb1_context *tdb, tdb1_off_t offset, struct tdb1_record *rec)
481 struct tdb1_record r = *rec;
482 return tdb->methods->tdb1_write(tdb, offset, TDB1_CONV(r), sizeof(r));
485 static const struct tdb1_methods io1_methods = {
488 tdb1_next_hash_chain,
494 initialise the default methods table
496 void tdb1_io_init(struct tdb1_context *tdb)
498 tdb->methods = &io1_methods;