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 2 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, write to the Free Software
26 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
30 #include "tdb_private.h"
32 /* check for an out of bounds access - if it is out of bounds then
33 see if the database has been expanded by someone else and expand
35 note that "len" is the minimum length needed for the db
37 static int tdb_oob(struct tdb_context *tdb, tdb_off_t len, int probe)
40 if (len <= tdb->map_size)
42 if (tdb->flags & TDB_INTERNAL) {
44 /* Ensure ecode is set for log fn. */
45 tdb->ecode = TDB_ERR_IO;
46 TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_oob len %d beyond internal malloc size %d\n",
47 (int)len, (int)tdb->map_size));
49 return TDB_ERRCODE(TDB_ERR_IO, -1);
52 if (fstat(tdb->fd, &st) == -1) {
53 return TDB_ERRCODE(TDB_ERR_IO, -1);
56 if (st.st_size < (size_t)len) {
58 /* Ensure ecode is set for log fn. */
59 tdb->ecode = TDB_ERR_IO;
60 TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_oob len %d beyond eof at %d\n",
61 (int)len, (int)st.st_size));
63 return TDB_ERRCODE(TDB_ERR_IO, -1);
66 /* Unmap, update size, remap */
67 if (tdb_munmap(tdb) == -1)
68 return TDB_ERRCODE(TDB_ERR_IO, -1);
69 tdb->map_size = st.st_size;
74 /* write a lump of data at a specified offset */
75 static int tdb_write(struct tdb_context *tdb, tdb_off_t off,
76 const void *buf, tdb_len_t len)
82 if (tdb->read_only || tdb->traverse_read) {
83 tdb->ecode = TDB_ERR_RDONLY;
87 if (tdb->methods->tdb_oob(tdb, off + len, 0) != 0)
91 memcpy(off + (char *)tdb->map_ptr, buf, len);
92 } else if (pwrite(tdb->fd, buf, len, off) != (ssize_t)len) {
93 /* Ensure ecode is set for log fn. */
94 tdb->ecode = TDB_ERR_IO;
95 TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_write failed at %d len=%d (%s)\n",
96 off, len, strerror(errno)));
97 return TDB_ERRCODE(TDB_ERR_IO, -1);
102 /* Endian conversion: we only ever deal with 4 byte quantities */
103 void *tdb_convert(void *buf, u32 size)
105 u32 i, *p = (u32 *)buf;
106 for (i = 0; i < size / 4; i++)
107 p[i] = TDB_BYTEREV(p[i]);
112 /* read a lump of data at a specified offset, maybe convert */
113 static int tdb_read(struct tdb_context *tdb, tdb_off_t off, void *buf,
114 tdb_len_t len, int cv)
116 if (tdb->methods->tdb_oob(tdb, off + len, 0) != 0) {
121 memcpy(buf, off + (char *)tdb->map_ptr, len);
123 ssize_t ret = pread(tdb->fd, buf, len, off);
124 if (ret != (ssize_t)len) {
125 /* Ensure ecode is set for log fn. */
126 tdb->ecode = TDB_ERR_IO;
127 TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_read failed at %d len=%d ret=%d (%s) map_size=%d\n",
128 off, len, ret, strerror(errno), (int)tdb->map_size));
129 return TDB_ERRCODE(TDB_ERR_IO, -1);
133 tdb_convert(buf, len);
141 do an unlocked scan of the hash table heads to find the next non-zero head. The value
142 will then be confirmed with the lock held
144 static void tdb_next_hash_chain(struct tdb_context *tdb, u32 *chain)
148 for (;h < tdb->header.hash_size;h++) {
149 if (0 != *(u32 *)(TDB_HASH_TOP(h) + (unsigned char *)tdb->map_ptr)) {
155 for (;h < tdb->header.hash_size;h++) {
156 if (tdb_ofs_read(tdb, TDB_HASH_TOP(h), &off) != 0 || off != 0) {
165 int tdb_munmap(struct tdb_context *tdb)
167 if (tdb->flags & TDB_INTERNAL)
172 int ret = munmap(tdb->map_ptr, tdb->map_size);
181 void tdb_mmap(struct tdb_context *tdb)
183 if (tdb->flags & TDB_INTERNAL)
187 if (!(tdb->flags & TDB_NOMMAP)) {
188 tdb->map_ptr = mmap(NULL, tdb->map_size,
189 PROT_READ|(tdb->read_only? 0:PROT_WRITE),
190 MAP_SHARED|MAP_FILE, tdb->fd, 0);
193 * NB. When mmap fails it returns MAP_FAILED *NOT* NULL !!!!
196 if (tdb->map_ptr == MAP_FAILED) {
198 TDB_LOG((tdb, TDB_DEBUG_WARNING, "tdb_mmap failed for size %d (%s)\n",
199 tdb->map_size, strerror(errno)));
209 /* expand a file. we prefer to use ftruncate, as that is what posix
210 says to use for mmap expansion */
211 static int tdb_expand_file(struct tdb_context *tdb, tdb_off_t size, tdb_off_t addition)
215 if (tdb->read_only || tdb->traverse_read) {
216 tdb->ecode = TDB_ERR_RDONLY;
220 if (ftruncate(tdb->fd, size+addition) == -1) {
222 if (pwrite(tdb->fd, &b, 1, (size+addition) - 1) != 1) {
223 TDB_LOG((tdb, TDB_DEBUG_FATAL, "expand_file to %d failed (%s)\n",
224 size+addition, strerror(errno)));
229 /* now fill the file with something. This ensures that the
230 file isn't sparse, which would be very bad if we ran out of
231 disk. This must be done with write, not via mmap */
232 memset(buf, TDB_PAD_BYTE, sizeof(buf));
234 int n = addition>sizeof(buf)?sizeof(buf):addition;
235 int ret = pwrite(tdb->fd, buf, n, size);
237 TDB_LOG((tdb, TDB_DEBUG_FATAL, "expand_file write of %d failed (%s)\n",
238 n, strerror(errno)));
248 /* expand the database at least size bytes by expanding the underlying
249 file and doing the mmap again if necessary */
250 int tdb_expand(struct tdb_context *tdb, tdb_off_t size)
252 struct list_struct rec;
255 if (tdb_lock(tdb, -1, F_WRLCK) == -1) {
256 TDB_LOG((tdb, TDB_DEBUG_ERROR, "lock failed in tdb_expand\n"));
260 /* must know about any previous expansions by another process */
261 tdb->methods->tdb_oob(tdb, tdb->map_size + 1, 1);
263 /* always make room for at least 10 more records, and round
264 the database up to a multiple of the page size */
265 size = TDB_ALIGN(tdb->map_size + size*10, tdb->page_size) - tdb->map_size;
267 if (!(tdb->flags & TDB_INTERNAL))
271 * We must ensure the file is unmapped before doing this
272 * to ensure consistency with systems like OpenBSD where
273 * writes and mmaps are not consistent.
276 /* expand the file itself */
277 if (!(tdb->flags & TDB_INTERNAL)) {
278 if (tdb->methods->tdb_expand_file(tdb, tdb->map_size, size) != 0)
282 tdb->map_size += size;
284 if (tdb->flags & TDB_INTERNAL) {
285 char *new_map_ptr = (char *)realloc(tdb->map_ptr,
288 tdb->map_size -= size;
291 tdb->map_ptr = new_map_ptr;
294 * We must ensure the file is remapped before adding the space
295 * to ensure consistency with systems like OpenBSD where
296 * writes and mmaps are not consistent.
299 /* We're ok if the mmap fails as we'll fallback to read/write */
303 /* form a new freelist record */
304 memset(&rec,'\0',sizeof(rec));
305 rec.rec_len = size - sizeof(rec);
307 /* link it into the free list */
308 offset = tdb->map_size - size;
309 if (tdb_free(tdb, offset, &rec) == -1)
312 tdb_unlock(tdb, -1, F_WRLCK);
315 tdb_unlock(tdb, -1, F_WRLCK);
319 /* read/write a tdb_off_t */
320 int tdb_ofs_read(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d)
322 return tdb->methods->tdb_read(tdb, offset, (char*)d, sizeof(*d), DOCONV());
325 int tdb_ofs_write(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d)
328 return tdb->methods->tdb_write(tdb, offset, CONVERT(off), sizeof(*d));
332 /* read a lump of data, allocating the space for it */
333 char *tdb_alloc_read(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t len)
337 /* some systems don't like zero length malloc */
342 if (!(buf = (char *)malloc(len))) {
343 /* Ensure ecode is set for log fn. */
344 tdb->ecode = TDB_ERR_OOM;
345 TDB_LOG((tdb, TDB_DEBUG_ERROR,"tdb_alloc_read malloc failed len=%d (%s)\n",
346 len, strerror(errno)));
347 return TDB_ERRCODE(TDB_ERR_OOM, buf);
349 if (tdb->methods->tdb_read(tdb, offset, buf, len, 0) == -1) {
356 /* read/write a record */
357 int tdb_rec_read(struct tdb_context *tdb, tdb_off_t offset, struct list_struct *rec)
359 if (tdb->methods->tdb_read(tdb, offset, rec, sizeof(*rec),DOCONV()) == -1)
361 if (TDB_BAD_MAGIC(rec)) {
362 /* Ensure ecode is set for log fn. */
363 tdb->ecode = TDB_ERR_CORRUPT;
364 TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_rec_read bad magic 0x%x at offset=%d\n", rec->magic, offset));
365 return TDB_ERRCODE(TDB_ERR_CORRUPT, -1);
367 return tdb->methods->tdb_oob(tdb, rec->next+sizeof(*rec), 0);
370 int tdb_rec_write(struct tdb_context *tdb, tdb_off_t offset, struct list_struct *rec)
372 struct list_struct r = *rec;
373 return tdb->methods->tdb_write(tdb, offset, CONVERT(r), sizeof(r));
376 static const struct tdb_methods io_methods = {
386 initialise the default methods table
388 void tdb_io_init(struct tdb_context *tdb)
390 tdb->methods = &io_methods;