source: vendor/3.5.0/lib/tdb/common/open.c

Last change on this file was 414, checked in by Herwig Bauernfeind, 16 years ago

Samba 3.5.0: Initial import
File size: 14.6 KB
Line 
1 /*
2 Unix SMB/CIFS implementation.
3
4 trivial database library
5
6 Copyright (C) Andrew Tridgell 1999-2005
7 Copyright (C) Paul `Rusty' Russell 2000
8 Copyright (C) Jeremy Allison 2000-2003
9
10 ** NOTE! The following LGPL license applies to the tdb
11 ** library. This does NOT imply that all of Samba is released
12 ** under the LGPL
13
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.
18
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.
23
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/>.
26*/
27
28#include "tdb_private.h"
29
30/* all contexts, to ensure no double-opens (fcntl locks don't nest!) */
31static struct tdb_context *tdbs = NULL;
32
33
34/* This is based on the hash algorithm from gdbm */
35static unsigned int default_tdb_hash(TDB_DATA *key)
36{
37 uint32_t value; /* Used to compute the hash value. */
38 uint32_t i; /* Used to cycle through random values. */
39
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)));
43
44 return (1103515243 * value + 12345);
45}
46
47
48/* initialise a new database with a specified hash size */
49static int tdb_new_database(struct tdb_context *tdb, int hash_size)
50{
51 struct tdb_header *newdb;
52 size_t size;
53 int ret = -1;
54 ssize_t written;
55
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 tdb->ecode = TDB_ERR_OOM;
60 return -1;
61 }
62
63 /* Fill in the header */
64 newdb->version = TDB_VERSION;
65 newdb->hash_size = hash_size;
66 if (tdb->flags & TDB_INTERNAL) {
67 tdb->map_size = size;
68 tdb->map_ptr = (char *)newdb;
69 memcpy(&tdb->header, newdb, sizeof(tdb->header));
70 /* Convert the `ondisk' version if asked. */
71 CONVERT(*newdb);
72 return 0;
73 }
74 if (lseek(tdb->fd, 0, SEEK_SET) == -1)
75 goto fail;
76
77 if (ftruncate(tdb->fd, 0) == -1)
78 goto fail;
79
80 /* This creates an endian-converted header, as if read from disk */
81 CONVERT(*newdb);
82 memcpy(&tdb->header, newdb, sizeof(tdb->header));
83 /* Don't endian-convert the magic food! */
84 memcpy(newdb->magic_food, TDB_MAGIC_FOOD, strlen(TDB_MAGIC_FOOD)+1);
85 /* we still have "ret == -1" here */
86 written = write(tdb->fd, newdb, size);
87 if (written == size) {
88 ret = 0;
89 } else if (written != -1) {
90 /* call write once again, this usually should return -1 and
91 * set errno appropriately */
92 size -= written;
93 written = write(tdb->fd, newdb+written, size);
94 if (written == size) {
95 ret = 0;
96 } else if (written >= 0) {
97 /* a second incomplete write - we give up.
98 * guessing the errno... */
99 errno = ENOSPC;
100 }
101 }
102
103 fail:
104 SAFE_FREE(newdb);
105 return ret;
106}
107
108
109
110static int tdb_already_open(dev_t device,
111 ino_t ino)
112{
113 struct tdb_context *i;
114
115 for (i = tdbs; i; i = i->next) {
116 if (i->device == device && i->inode == ino) {
117 return 1;
118 }
119 }
120
121 return 0;
122}
123
124/* open the database, creating it if necessary
125
126 The open_flags and mode are passed straight to the open call on the
127 database file. A flags value of O_WRONLY is invalid. The hash size
128 is advisory, use zero for a default value.
129
130 Return is NULL on error, in which case errno is also set. Don't
131 try to call tdb_error or tdb_errname, just do strerror(errno).
132
133 @param name may be NULL for internal databases. */
134struct tdb_context *tdb_open(const char *name, int hash_size, int tdb_flags,
135 int open_flags, mode_t mode)
136{
137 return tdb_open_ex(name, hash_size, tdb_flags, open_flags, mode, NULL, NULL);
138}
139
140/* a default logging function */
141static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...) PRINTF_ATTRIBUTE(3, 4);
142static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...)
143{
144}
145
146
147struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
148 int open_flags, mode_t mode,
149 const struct tdb_logging_context *log_ctx,
150 tdb_hash_func hash_fn)
151{
152 struct tdb_context *tdb;
153 struct stat st;
154 int rev = 0, locked = 0;
155 unsigned char *vp;
156 uint32_t vertest;
157 unsigned v;
158
159 if (!(tdb = (struct tdb_context *)calloc(1, sizeof *tdb))) {
160 /* Can't log this */
161 errno = ENOMEM;
162 goto fail;
163 }
164 tdb_io_init(tdb);
165 tdb->fd = -1;
166#ifdef TDB_TRACE
167 tdb->tracefd = -1;
168#endif
169 tdb->name = NULL;
170 tdb->map_ptr = NULL;
171 tdb->flags = tdb_flags;
172 tdb->open_flags = open_flags;
173 if (log_ctx) {
174 tdb->log = *log_ctx;
175 } else {
176 tdb->log.log_fn = null_log_fn;
177 tdb->log.log_private = NULL;
178 }
179 tdb->hash_fn = hash_fn ? hash_fn : default_tdb_hash;
180
181 /* cache the page size */
182 tdb->page_size = getpagesize();
183 if (tdb->page_size <= 0) {
184 tdb->page_size = 0x2000;
185 }
186
187 tdb->max_dead_records = (tdb_flags & TDB_VOLATILE) ? 5 : 0;
188
189 if ((open_flags & O_ACCMODE) == O_WRONLY) {
190 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: can't open tdb %s write-only\n",
191 name));
192 errno = EINVAL;
193 goto fail;
194 }
195
196 if (hash_size == 0)
197 hash_size = DEFAULT_HASH_SIZE;
198 if ((open_flags & O_ACCMODE) == O_RDONLY) {
199 tdb->read_only = 1;
200 /* read only databases don't do locking or clear if first */
201 tdb->flags |= TDB_NOLOCK;
202 tdb->flags &= ~TDB_CLEAR_IF_FIRST;
203 }
204
205 if ((tdb->flags & TDB_ALLOW_NESTING) &&
206 (tdb->flags & TDB_DISALLOW_NESTING)) {
207 tdb->ecode = TDB_ERR_NESTING;
208 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
209 "allow_nesting and disallow_nesting are not allowed together!"));
210 errno = EINVAL;
211 goto fail;
212 }
213
214 /*
215 * TDB_ALLOW_NESTING is the default behavior.
216 * Note: this may change in future versions!
217 */
218 if (!(tdb->flags & TDB_DISALLOW_NESTING)) {
219 tdb->flags |= TDB_ALLOW_NESTING;
220 }
221
222 /* internal databases don't mmap or lock, and start off cleared */
223 if (tdb->flags & TDB_INTERNAL) {
224 tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP);
225 tdb->flags &= ~TDB_CLEAR_IF_FIRST;
226 if (tdb_new_database(tdb, hash_size) != 0) {
227 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: tdb_new_database failed!"));
228 goto fail;
229 }
230 goto internal;
231 }
232
233 if ((tdb->fd = open(name, open_flags, mode)) == -1) {
234 TDB_LOG((tdb, TDB_DEBUG_WARNING, "tdb_open_ex: could not open file %s: %s\n",
235 name, strerror(errno)));
236 goto fail; /* errno set by open(2) */
237 }
238
239 /* on exec, don't inherit the fd */
240 v = fcntl(tdb->fd, F_GETFD, 0);
241 fcntl(tdb->fd, F_SETFD, v | FD_CLOEXEC);
242
243 /* ensure there is only one process initialising at once */
244 if (tdb->methods->tdb_brlock(tdb, GLOBAL_LOCK, F_WRLCK, F_SETLKW, 0, 1) == -1) {
245 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to get global lock on %s: %s\n",
246 name, strerror(errno)));
247 goto fail; /* errno set by tdb_brlock */
248 }
249
250 /* we need to zero database if we are the only one with it open */
251 if ((tdb_flags & TDB_CLEAR_IF_FIRST) &&
252 (!tdb->read_only) &&
253 (locked = (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_WRLCK, F_SETLK, 0, 1) == 0))) {
254 open_flags |= O_CREAT;
255 if (ftruncate(tdb->fd, 0) == -1) {
256 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
257 "failed to truncate %s: %s\n",
258 name, strerror(errno)));
259 goto fail; /* errno set by ftruncate */
260 }
261 }
262
263 errno = 0;
264 if (read(tdb->fd, &tdb->header, sizeof(tdb->header)) != sizeof(tdb->header)
265 || strcmp(tdb->header.magic_food, TDB_MAGIC_FOOD) != 0) {
266 if (!(open_flags & O_CREAT) || tdb_new_database(tdb, hash_size) == -1) {
267 if (errno == 0) {
268 errno = EIO; /* ie bad format or something */
269 }
270 goto fail;
271 }
272 rev = (tdb->flags & TDB_CONVERT);
273 } else if (tdb->header.version != TDB_VERSION
274 && !(rev = (tdb->header.version==TDB_BYTEREV(TDB_VERSION)))) {
275 /* wrong version */
276 errno = EIO;
277 goto fail;
278 }
279 vp = (unsigned char *)&tdb->header.version;
280 vertest = (((uint32_t)vp[0]) << 24) | (((uint32_t)vp[1]) << 16) |
281 (((uint32_t)vp[2]) << 8) | (uint32_t)vp[3];
282 tdb->flags |= (vertest==TDB_VERSION) ? TDB_BIGENDIAN : 0;
283 if (!rev)
284 tdb->flags &= ~TDB_CONVERT;
285 else {
286 tdb->flags |= TDB_CONVERT;
287 tdb_convert(&tdb->header, sizeof(tdb->header));
288 }
289 if (fstat(tdb->fd, &st) == -1)
290 goto fail;
291
292 if (tdb->header.rwlocks != 0) {
293 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: spinlocks no longer supported\n"));
294 goto fail;
295 }
296
297 /* Is it already in the open list? If so, fail. */
298 if (tdb_already_open(st.st_dev, st.st_ino)) {
299 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
300 "%s (%d,%d) is already open in this process\n",
301 name, (int)st.st_dev, (int)st.st_ino));
302 errno = EBUSY;
303 goto fail;
304 }
305
306 if (!(tdb->name = (char *)strdup(name))) {
307 errno = ENOMEM;
308 goto fail;
309 }
310
311 tdb->map_size = st.st_size;
312 tdb->device = st.st_dev;
313 tdb->inode = st.st_ino;
314 tdb_mmap(tdb);
315 if (locked) {
316 if (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_UNLCK, F_SETLK, 0, 1) == -1) {
317 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
318 "failed to take ACTIVE_LOCK on %s: %s\n",
319 name, strerror(errno)));
320 goto fail;
321 }
322
323 }
324
325 /* We always need to do this if the CLEAR_IF_FIRST flag is set, even if
326 we didn't get the initial exclusive lock as we need to let all other
327 users know we're using it. */
328
329 if (tdb_flags & TDB_CLEAR_IF_FIRST) {
330 /* leave this lock in place to indicate it's in use */
331 if (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_RDLCK, F_SETLKW, 0, 1) == -1)
332 goto fail;
333 }
334
335 /* if needed, run recovery */
336 if (tdb_transaction_recover(tdb) == -1) {
337 goto fail;
338 }
339
340#ifdef TDB_TRACE
341 {
342 char tracefile[strlen(name) + 32];
343
344 snprintf(tracefile, sizeof(tracefile),
345 "%s.trace.%li", name, (long)getpid());
346 tdb->tracefd = open(tracefile, O_WRONLY|O_CREAT|O_EXCL, 0600);
347 if (tdb->tracefd >= 0) {
348 tdb_enable_seqnum(tdb);
349 tdb_trace_open(tdb, "tdb_open", hash_size, tdb_flags,
350 open_flags);
351 } else
352 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to open trace file %s!\n", tracefile));
353 }
354#endif
355
356 internal:
357 /* Internal (memory-only) databases skip all the code above to
358 * do with disk files, and resume here by releasing their
359 * global lock and hooking into the active list. */
360 if (tdb->methods->tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1) == -1)
361 goto fail;
362 tdb->next = tdbs;
363 tdbs = tdb;
364 return tdb;
365
366 fail:
367 { int save_errno = errno;
368
369 if (!tdb)
370 return NULL;
371
372#ifdef TDB_TRACE
373 close(tdb->tracefd);
374#endif
375 if (tdb->map_ptr) {
376 if (tdb->flags & TDB_INTERNAL)
377 SAFE_FREE(tdb->map_ptr);
378 else
379 tdb_munmap(tdb);
380 }
381 SAFE_FREE(tdb->name);
382 if (tdb->fd != -1)
383 if (close(tdb->fd) != 0)
384 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to close tdb->fd on error!\n"));
385 SAFE_FREE(tdb);
386 errno = save_errno;
387 return NULL;
388 }
389}
390
391/*
392 * Set the maximum number of dead records per hash chain
393 */
394
395void tdb_set_max_dead(struct tdb_context *tdb, int max_dead)
396{
397 tdb->max_dead_records = max_dead;
398}
399
400/**
401 * Close a database.
402 *
403 * @returns -1 for error; 0 for success.
404 **/
405int tdb_close(struct tdb_context *tdb)
406{
407 struct tdb_context **i;
408 int ret = 0;
409
410 tdb_trace(tdb, "tdb_close");
411 if (tdb->transaction) {
412 _tdb_transaction_cancel(tdb);
413 }
414
415 if (tdb->map_ptr) {
416 if (tdb->flags & TDB_INTERNAL)
417 SAFE_FREE(tdb->map_ptr);
418 else
419 tdb_munmap(tdb);
420 }
421 SAFE_FREE(tdb->name);
422 if (tdb->fd != -1) {
423 ret = close(tdb->fd);
424 tdb->fd = -1;
425 }
426 SAFE_FREE(tdb->lockrecs);
427
428 /* Remove from contexts list */
429 for (i = &tdbs; *i; i = &(*i)->next) {
430 if (*i == tdb) {
431 *i = tdb->next;
432 break;
433 }
434 }
435
436#ifdef TDB_TRACE
437 close(tdb->tracefd);
438#endif
439 memset(tdb, 0, sizeof(*tdb));
440 SAFE_FREE(tdb);
441
442 return ret;
443}
444
445/* register a loging function */
446void tdb_set_logging_function(struct tdb_context *tdb,
447 const struct tdb_logging_context *log_ctx)
448{
449 tdb->log = *log_ctx;
450}
451
452void *tdb_get_logging_private(struct tdb_context *tdb)
453{
454 return tdb->log.log_private;
455}
456
457static int tdb_reopen_internal(struct tdb_context *tdb, bool active_lock)
458{
459#if !defined(LIBREPLACE_PREAD_NOT_REPLACED) || \
460 !defined(LIBREPLACE_PWRITE_NOT_REPLACED)
461 struct stat st;
462#endif
463
464 if (tdb->flags & TDB_INTERNAL) {
465 return 0; /* Nothing to do. */
466 }
467
468 if (tdb->num_locks != 0 || tdb->global_lock.count) {
469 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed with locks held\n"));
470 goto fail;
471 }
472
473 if (tdb->transaction != 0) {
474 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed inside a transaction\n"));
475 goto fail;
476 }
477
478/* If we have real pread & pwrite, we can skip reopen. */
479#if !defined(LIBREPLACE_PREAD_NOT_REPLACED) || \
480 !defined(LIBREPLACE_PWRITE_NOT_REPLACED)
481 if (tdb_munmap(tdb) != 0) {
482 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: munmap failed (%s)\n", strerror(errno)));
483 goto fail;
484 }
485 if (close(tdb->fd) != 0)
486 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: WARNING closing tdb->fd failed!\n"));
487 tdb->fd = open(tdb->name, tdb->open_flags & ~(O_CREAT|O_TRUNC), 0);
488 if (tdb->fd == -1) {
489 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: open failed (%s)\n", strerror(errno)));
490 goto fail;
491 }
492 if (fstat(tdb->fd, &st) != 0) {
493 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: fstat failed (%s)\n", strerror(errno)));
494 goto fail;
495 }
496 if (st.st_ino != tdb->inode || st.st_dev != tdb->device) {
497 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: file dev/inode has changed!\n"));
498 goto fail;
499 }
500 tdb_mmap(tdb);
501#endif /* fake pread or pwrite */
502
503 if (active_lock &&
504 (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_RDLCK, F_SETLKW, 0, 1) == -1)) {
505 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: failed to obtain active lock\n"));
506 goto fail;
507 }
508
509 return 0;
510
511fail:
512 tdb_close(tdb);
513 return -1;
514}
515
516/* reopen a tdb - this can be used after a fork to ensure that we have an independent
517 seek pointer from our parent and to re-establish locks */
518int tdb_reopen(struct tdb_context *tdb)
519{
520 return tdb_reopen_internal(tdb, tdb->flags & TDB_CLEAR_IF_FIRST);
521}
522
523/* reopen all tdb's */
524int tdb_reopen_all(int parent_longlived)
525{
526 struct tdb_context *tdb;
527
528 for (tdb=tdbs; tdb; tdb = tdb->next) {
529 bool active_lock = (tdb->flags & TDB_CLEAR_IF_FIRST);
530
531 /*
532 * If the parent is longlived (ie. a
533 * parent daemon architecture), we know
534 * it will keep it's active lock on a
535 * tdb opened with CLEAR_IF_FIRST. Thus
536 * for child processes we don't have to
537 * add an active lock. This is essential
538 * to improve performance on systems that
539 * keep POSIX locks as a non-scalable data
540 * structure in the kernel.
541 */
542 if (parent_longlived) {
543 /* Ensure no clear-if-first. */
544 active_lock = false;
545 }
546
547 if (tdb_reopen_internal(tdb, active_lock) != 0)
548 return -1;
549 }
550
551 return 0;
552}
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