dd5783ef8bc959409a962d56ad50b0b24490bd8f
[samba.git] / lib / tdb / common / open.c
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!) */
31 static struct tdb_context *tdbs = NULL;
32
33 /* We use two hashes to double-check they're using the right hash function. */
34 void tdb_header_hash(struct tdb_context *tdb,
35                      uint32_t *magic1_hash, uint32_t *magic2_hash)
36 {
37         TDB_DATA hash_key;
38         uint32_t tdb_magic = TDB_MAGIC;
39
40         hash_key.dptr = discard_const_p(unsigned char, TDB_MAGIC_FOOD);
41         hash_key.dsize = sizeof(TDB_MAGIC_FOOD);
42         *magic1_hash = tdb->hash_fn(&hash_key);
43
44         hash_key.dptr = (unsigned char *)CONVERT(tdb_magic);
45         hash_key.dsize = sizeof(tdb_magic);
46         *magic2_hash = tdb->hash_fn(&hash_key);
47
48         /* Make sure at least one hash is non-zero! */
49         if (*magic1_hash == 0 && *magic2_hash == 0)
50                 *magic1_hash = 1;
51 }
52
53 /* initialise a new database with a specified hash size */
54 static int tdb_new_database(struct tdb_context *tdb, struct tdb_header *header,
55                             int hash_size)
56 {
57         struct tdb_header *newdb;
58         size_t size;
59         int ret = -1;
60
61         /* We make it up in memory, then write it out if not internal */
62         size = sizeof(struct tdb_header) + (hash_size+1)*sizeof(tdb_off_t);
63         if (!(newdb = (struct tdb_header *)calloc(size, 1))) {
64                 tdb->ecode = TDB_ERR_OOM;
65                 return -1;
66         }
67
68         /* Fill in the header */
69         newdb->version = TDB_VERSION;
70         newdb->hash_size = hash_size;
71
72         tdb_header_hash(tdb, &newdb->magic1_hash, &newdb->magic2_hash);
73
74         /* Make sure older tdbs (which don't check the magic hash fields)
75          * will refuse to open this TDB. */
76         if (tdb->flags & TDB_INCOMPATIBLE_HASH)
77                 newdb->rwlocks = TDB_HASH_RWLOCK_MAGIC;
78
79         /*
80          * We create a tdb with TDB_FEATURE_FLAG_MUTEX support,
81          * the flag combination and runtime feature checks
82          * are done by the caller already.
83          */
84         if (tdb->flags & TDB_MUTEX_LOCKING) {
85                 newdb->feature_flags |= TDB_FEATURE_FLAG_MUTEX;
86         }
87
88         /*
89          * If we have any features we add the FEATURE_FLAG_MAGIC, overwriting the
90          * TDB_HASH_RWLOCK_MAGIC above.
91          */
92         if (newdb->feature_flags != 0) {
93                 newdb->rwlocks = TDB_FEATURE_FLAG_MAGIC;
94         }
95
96         /*
97          * It's required for some following code pathes
98          * to have the fields on 'tdb' up-to-date.
99          *
100          * E.g. tdb_mutex_size() requires it
101          */
102         tdb->feature_flags = newdb->feature_flags;
103         tdb->hash_size = newdb->hash_size;
104
105         if (tdb->flags & TDB_INTERNAL) {
106                 tdb->map_size = size;
107                 tdb->map_ptr = (char *)newdb;
108                 memcpy(header, newdb, sizeof(*header));
109                 /* Convert the `ondisk' version if asked. */
110                 CONVERT(*newdb);
111                 return 0;
112         }
113         if (lseek(tdb->fd, 0, SEEK_SET) == -1)
114                 goto fail;
115
116         if (ftruncate(tdb->fd, 0) == -1)
117                 goto fail;
118
119         if (newdb->feature_flags & TDB_FEATURE_FLAG_MUTEX) {
120                 newdb->mutex_size = tdb_mutex_size(tdb);
121                 tdb->hdr_ofs = newdb->mutex_size;
122         }
123
124         /* This creates an endian-converted header, as if read from disk */
125         CONVERT(*newdb);
126         memcpy(header, newdb, sizeof(*header));
127         /* Don't endian-convert the magic food! */
128         memcpy(newdb->magic_food, TDB_MAGIC_FOOD, strlen(TDB_MAGIC_FOOD)+1);
129
130         if (!tdb_write_all(tdb->fd, newdb, size))
131                 goto fail;
132
133         if (newdb->feature_flags & TDB_FEATURE_FLAG_MUTEX) {
134
135                 /*
136                  * Now we init the mutex area
137                  * followed by a second header.
138                  */
139
140                 ret = ftruncate(
141                         tdb->fd,
142                         newdb->mutex_size + sizeof(struct tdb_header));
143                 if (ret == -1) {
144                         goto fail;
145                 }
146                 ret = tdb_mutex_init(tdb);
147                 if (ret == -1) {
148                         goto fail;
149                 }
150
151                 /*
152                  * Write a second header behind the mutexes. That's the area
153                  * that will be mmapp'ed.
154                  */
155                 ret = lseek(tdb->fd, newdb->mutex_size, SEEK_SET);
156                 if (ret == -1) {
157                         goto fail;
158                 }
159                 if (!tdb_write_all(tdb->fd, newdb, size)) {
160                         goto fail;
161                 }
162         }
163
164         ret = 0;
165   fail:
166         SAFE_FREE(newdb);
167         return ret;
168 }
169
170
171
172 static int tdb_already_open(dev_t device,
173                             ino_t ino)
174 {
175         struct tdb_context *i;
176
177         for (i = tdbs; i; i = i->next) {
178                 if (i->device == device && i->inode == ino) {
179                         return 1;
180                 }
181         }
182
183         return 0;
184 }
185
186 /* open the database, creating it if necessary
187
188    The open_flags and mode are passed straight to the open call on the
189    database file. A flags value of O_WRONLY is invalid. The hash size
190    is advisory, use zero for a default value.
191
192    Return is NULL on error, in which case errno is also set.  Don't
193    try to call tdb_error or tdb_errname, just do strerror(errno).
194
195    @param name may be NULL for internal databases. */
196 _PUBLIC_ struct tdb_context *tdb_open(const char *name, int hash_size, int tdb_flags,
197                       int open_flags, mode_t mode)
198 {
199         return tdb_open_ex(name, hash_size, tdb_flags, open_flags, mode, NULL, NULL);
200 }
201
202 /* a default logging function */
203 static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...) PRINTF_ATTRIBUTE(3, 4);
204 static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...)
205 {
206 }
207
208 static bool check_header_hash(struct tdb_context *tdb,
209                               struct tdb_header *header,
210                               bool default_hash, uint32_t *m1, uint32_t *m2)
211 {
212         tdb_header_hash(tdb, m1, m2);
213         if (header->magic1_hash == *m1 &&
214             header->magic2_hash == *m2) {
215                 return true;
216         }
217
218         /* If they explicitly set a hash, always respect it. */
219         if (!default_hash)
220                 return false;
221
222         /* Otherwise, try the other inbuilt hash. */
223         if (tdb->hash_fn == tdb_old_hash)
224                 tdb->hash_fn = tdb_jenkins_hash;
225         else
226                 tdb->hash_fn = tdb_old_hash;
227         return check_header_hash(tdb, header, false, m1, m2);
228 }
229
230 static bool tdb_mutex_open_ok(struct tdb_context *tdb,
231                               const struct tdb_header *header)
232 {
233         if (tdb->flags & TDB_NOLOCK) {
234                 /*
235                  * We don't look at locks, so it does not matter to have a
236                  * compatible mutex implementation. Allow the open.
237                  */
238                 return true;
239         }
240
241         if (!(tdb->flags & TDB_MUTEX_LOCKING)) {
242                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_mutex_open_ok[%s]: "
243                          "Can use mutexes only with "
244                          "MUTEX_LOCKING or NOLOCK\n",
245                          tdb->name));
246                 return false;
247         }
248
249         if (tdb_mutex_size(tdb) != header->mutex_size) {
250                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_mutex_open_ok[%s]: "
251                          "Mutex size changed from %"PRIu32" to %zu\n.",
252                          tdb->name,
253                          header->mutex_size,
254                          tdb_mutex_size(tdb)));
255                 return false;
256         }
257
258         return true;
259 }
260
261 _PUBLIC_ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
262                                 int open_flags, mode_t mode,
263                                 const struct tdb_logging_context *log_ctx,
264                                 tdb_hash_func hash_fn)
265 {
266         int orig_errno = errno;
267         struct tdb_header header = {
268                 .version = 0,
269         };
270         struct tdb_context *tdb;
271         struct stat st;
272         int rev = 0;
273         bool locked = false;
274         unsigned char *vp;
275         uint32_t vertest;
276         unsigned v;
277         const char *hash_alg;
278         uint32_t magic1, magic2;
279         int ret;
280
281         if (!(tdb = (struct tdb_context *)calloc(1, sizeof *tdb))) {
282                 /* Can't log this */
283                 errno = ENOMEM;
284                 goto fail;
285         }
286         tdb_io_init(tdb);
287
288         if (tdb_flags & TDB_INTERNAL) {
289                 tdb_flags |= TDB_INCOMPATIBLE_HASH;
290         }
291         if (tdb_flags & TDB_MUTEX_LOCKING) {
292                 tdb_flags |= TDB_INCOMPATIBLE_HASH;
293         }
294
295         tdb->fd = -1;
296 #ifdef TDB_TRACE
297         tdb->tracefd = -1;
298 #endif
299         tdb->name = NULL;
300         tdb->map_ptr = NULL;
301         tdb->flags = tdb_flags;
302         tdb->open_flags = open_flags;
303         if (log_ctx) {
304                 tdb->log = *log_ctx;
305         } else {
306                 tdb->log.log_fn = null_log_fn;
307                 tdb->log.log_private = NULL;
308         }
309
310         if (name == NULL && (tdb_flags & TDB_INTERNAL)) {
311                 name = "__TDB_INTERNAL__";
312         }
313
314         if (name == NULL) {
315                 tdb->name = discard_const_p(char, "__NULL__");
316                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: called with name == NULL\n"));
317                 tdb->name = NULL;
318                 errno = EINVAL;
319                 goto fail;
320         }
321
322         /* now make a copy of the name, as the caller memory might go away */
323         if (!(tdb->name = (char *)strdup(name))) {
324                 /*
325                  * set the name as the given string, so that tdb_name() will
326                  * work in case of an error.
327                  */
328                 tdb->name = discard_const_p(char, name);
329                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: can't strdup(%s)\n",
330                          name));
331                 tdb->name = NULL;
332                 errno = ENOMEM;
333                 goto fail;
334         }
335
336         if (hash_fn) {
337                 tdb->hash_fn = hash_fn;
338                 hash_alg = "the user defined";
339         } else {
340                 /* This controls what we use when creating a tdb. */
341                 if (tdb->flags & TDB_INCOMPATIBLE_HASH) {
342                         tdb->hash_fn = tdb_jenkins_hash;
343                 } else {
344                         tdb->hash_fn = tdb_old_hash;
345                 }
346                 hash_alg = "either default";
347         }
348
349         /* cache the page size */
350         tdb->page_size = getpagesize();
351         if (tdb->page_size <= 0) {
352                 tdb->page_size = 0x2000;
353         }
354
355         tdb->max_dead_records = (tdb_flags & TDB_VOLATILE) ? 5 : 0;
356
357         if ((open_flags & O_ACCMODE) == O_WRONLY) {
358                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: can't open tdb %s write-only\n",
359                          name));
360                 errno = EINVAL;
361                 goto fail;
362         }
363
364         if (hash_size == 0)
365                 hash_size = DEFAULT_HASH_SIZE;
366         if ((open_flags & O_ACCMODE) == O_RDONLY) {
367                 tdb->read_only = 1;
368                 /* read only databases don't do locking or clear if first */
369                 tdb->flags |= TDB_NOLOCK;
370                 tdb->flags &= ~(TDB_CLEAR_IF_FIRST|TDB_MUTEX_LOCKING);
371         }
372
373         if ((tdb->flags & TDB_ALLOW_NESTING) &&
374             (tdb->flags & TDB_DISALLOW_NESTING)) {
375                 tdb->ecode = TDB_ERR_NESTING;
376                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
377                         "allow_nesting and disallow_nesting are not allowed together!"));
378                 errno = EINVAL;
379                 goto fail;
380         }
381
382         if (tdb->flags & TDB_MUTEX_LOCKING) {
383                 /*
384                  * Here we catch bugs in the callers,
385                  * the runtime check for existing tdb's comes later.
386                  */
387
388                 if (tdb->flags & TDB_INTERNAL) {
389                         TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
390                                 "invalid flags for %s - TDB_MUTEX_LOCKING and "
391                                 "TDB_INTERNAL are not allowed together\n", name));
392                         errno = EINVAL;
393                         goto fail;
394                 }
395
396                 if (tdb->flags & TDB_NOMMAP) {
397                         TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
398                                 "invalid flags for %s - TDB_MUTEX_LOCKING and "
399                                 "TDB_NOMMAP are not allowed together\n", name));
400                         errno = EINVAL;
401                         goto fail;
402                 }
403
404                 if (tdb->read_only) {
405                         TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
406                                 "invalid flags for %s - TDB_MUTEX_LOCKING "
407                                 "not allowed read only\n", name));
408                         errno = EINVAL;
409                         goto fail;
410                 }
411
412                 /*
413                  * The callers should have called
414                  * tdb_runtime_check_for_robust_mutexes()
415                  * before using TDB_MUTEX_LOCKING!
416                  *
417                  * This makes sure the caller understands
418                  * that the locking may behave a bit differently
419                  * than with pure fcntl locking. E.g. multiple
420                  * read locks are not supported.
421                  */
422                 if (!tdb_runtime_check_for_robust_mutexes()) {
423                         TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
424                                 "invalid flags for %s - TDB_MUTEX_LOCKING "
425                                 "requires support for robust_mutexes\n",
426                                 name));
427                         errno = ENOSYS;
428                         goto fail;
429                 }
430         }
431
432         if (getenv("TDB_NO_FSYNC")) {
433                 tdb->flags |= TDB_NOSYNC;
434         }
435
436         /*
437          * TDB_ALLOW_NESTING is the default behavior.
438          * Note: this may change in future versions!
439          */
440         if (!(tdb->flags & TDB_DISALLOW_NESTING)) {
441                 tdb->flags |= TDB_ALLOW_NESTING;
442         }
443
444         /* internal databases don't mmap or lock, and start off cleared */
445         if (tdb->flags & TDB_INTERNAL) {
446                 tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP);
447                 tdb->flags &= ~TDB_CLEAR_IF_FIRST;
448                 if (tdb_new_database(tdb, &header, hash_size) != 0) {
449                         TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: tdb_new_database failed!"));
450                         goto fail;
451                 }
452                 tdb->hash_size = hash_size;
453                 goto internal;
454         }
455
456         if ((tdb->fd = open(name, open_flags, mode)) == -1) {
457                 TDB_LOG((tdb, TDB_DEBUG_WARNING, "tdb_open_ex: could not open file %s: %s\n",
458                          name, strerror(errno)));
459                 goto fail;      /* errno set by open(2) */
460         }
461
462         /* on exec, don't inherit the fd */
463         v = fcntl(tdb->fd, F_GETFD, 0);
464         fcntl(tdb->fd, F_SETFD, v | FD_CLOEXEC);
465
466         /* ensure there is only one process initialising at once */
467         if (tdb_nest_lock(tdb, OPEN_LOCK, F_WRLCK, TDB_LOCK_WAIT) == -1) {
468                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to get open lock on %s: %s\n",
469                          name, strerror(errno)));
470                 goto fail;      /* errno set by tdb_brlock */
471         }
472
473         /* we need to zero database if we are the only one with it open */
474         if ((tdb_flags & TDB_CLEAR_IF_FIRST) &&
475             (!tdb->read_only)) {
476                 ret = tdb_nest_lock(tdb, ACTIVE_LOCK, F_WRLCK,
477                                     TDB_LOCK_NOWAIT|TDB_LOCK_PROBE);
478                 locked = (ret == 0);
479
480                 if (locked) {
481                         ret = tdb_brlock(tdb, F_WRLCK, FREELIST_TOP, 0,
482                                          TDB_LOCK_WAIT);
483                         if (ret == -1) {
484                                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
485                                          "tdb_brlock failed for %s: %s\n",
486                                          name, strerror(errno)));
487                                 goto fail;
488                         }
489                         ret = tdb_new_database(tdb, &header, hash_size);
490                         if (ret == -1) {
491                                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
492                                          "tdb_new_database failed for "
493                                          "%s: %s\n", name, strerror(errno)));
494                                 tdb_unlockall(tdb);
495                                 goto fail;
496                         }
497                         ret = tdb_brunlock(tdb, F_WRLCK, FREELIST_TOP, 0);
498                         if (ret == -1) {
499                                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
500                                          "tdb_unlockall failed for %s: %s\n",
501                                          name, strerror(errno)));
502                                 goto fail;
503                         }
504                         ret = lseek(tdb->fd, 0, SEEK_SET);
505                         if (ret == -1) {
506                                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
507                                          "lseek failed for %s: %s\n",
508                                          name, strerror(errno)));
509                                 goto fail;
510                         }
511                 }
512         }
513
514         errno = 0;
515         if (read(tdb->fd, &header, sizeof(header)) != sizeof(header)
516             || strcmp(header.magic_food, TDB_MAGIC_FOOD) != 0) {
517                 if (!(open_flags & O_CREAT) ||
518                     tdb_new_database(tdb, &header, hash_size) == -1) {
519                         if (errno == 0) {
520                                 errno = EIO; /* ie bad format or something */
521                         }
522                         goto fail;
523                 }
524                 rev = (tdb->flags & TDB_CONVERT);
525         } else if (header.version != TDB_VERSION
526                    && !(rev = (header.version==TDB_BYTEREV(TDB_VERSION)))) {
527                 /* wrong version */
528                 errno = EIO;
529                 goto fail;
530         }
531         vp = (unsigned char *)&header.version;
532         vertest = (((uint32_t)vp[0]) << 24) | (((uint32_t)vp[1]) << 16) |
533                   (((uint32_t)vp[2]) << 8) | (uint32_t)vp[3];
534         tdb->flags |= (vertest==TDB_VERSION) ? TDB_BIGENDIAN : 0;
535         if (!rev)
536                 tdb->flags &= ~TDB_CONVERT;
537         else {
538                 tdb->flags |= TDB_CONVERT;
539                 tdb_convert(&header, sizeof(header));
540         }
541
542         /*
543          * We only use st.st_dev and st.st_ino from the raw fstat()
544          * call, everything else needs to use tdb_fstat() in order
545          * to skip tdb->hdr_ofs!
546          */
547         if (fstat(tdb->fd, &st) == -1) {
548                 goto fail;
549         }
550         tdb->device = st.st_dev;
551         tdb->inode = st.st_ino;
552         ZERO_STRUCT(st);
553
554         if (header.rwlocks != 0 &&
555             header.rwlocks != TDB_FEATURE_FLAG_MAGIC &&
556             header.rwlocks != TDB_HASH_RWLOCK_MAGIC) {
557                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: spinlocks no longer supported\n"));
558                 errno = ENOSYS;
559                 goto fail;
560         }
561
562         if (header.hash_size == 0) {
563                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: invalid database: 0 hash_size\n"));
564                 errno = ENOSYS;
565                 goto fail;
566         }
567
568         tdb->hash_size = header.hash_size;
569
570         if (header.rwlocks == TDB_FEATURE_FLAG_MAGIC) {
571                 tdb->feature_flags = header.feature_flags;
572         }
573
574         if (tdb->feature_flags & ~TDB_SUPPORTED_FEATURE_FLAGS) {
575                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: unsupported "
576                          "features in tdb %s: 0x%08x (supported: 0x%08x)\n",
577                          name, (unsigned)tdb->feature_flags,
578                          (unsigned)TDB_SUPPORTED_FEATURE_FLAGS));
579                 errno = ENOSYS;
580                 goto fail;
581         }
582
583         if (tdb->feature_flags & TDB_FEATURE_FLAG_MUTEX) {
584                 if (!tdb_mutex_open_ok(tdb, &header)) {
585                         errno = EINVAL;
586                         goto fail;
587                 }
588
589                 /*
590                  * We need to remember the hdr_ofs
591                  * also for the TDB_NOLOCK case
592                  * if the current library doesn't support
593                  * mutex locking.
594                  */
595                 tdb->hdr_ofs = header.mutex_size;
596
597                 if ((!(tdb_flags & TDB_CLEAR_IF_FIRST)) && (!tdb->read_only)) {
598                         /*
599                          * Open an existing mutexed tdb, but without
600                          * CLEAR_IF_FIRST. We need to initialize the
601                          * mutex array and keep the CLEAR_IF_FIRST
602                          * lock locked.
603                          */
604                         ret = tdb_nest_lock(tdb, ACTIVE_LOCK, F_WRLCK,
605                                             TDB_LOCK_NOWAIT|TDB_LOCK_PROBE);
606                         locked = (ret == 0);
607
608                         if (locked) {
609                                 ret = tdb_mutex_init(tdb);
610                                 if (ret == -1) {
611                                         TDB_LOG((tdb,
612                                                  TDB_DEBUG_FATAL,
613                                                  "tdb_open_ex: tdb_mutex_init "
614                                                  "failed for ""%s: %s\n",
615                                                  name, strerror(errno)));
616                                         goto fail;
617                                 }
618                         }
619                 }
620         }
621
622         if ((header.magic1_hash == 0) && (header.magic2_hash == 0)) {
623                 /* older TDB without magic hash references */
624                 tdb->hash_fn = tdb_old_hash;
625         } else if (!check_header_hash(tdb, &header, !hash_fn,
626                                       &magic1, &magic2)) {
627                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
628                          "%s was not created with %s hash function we are using\n"
629                          "magic1_hash[0x%08X %s 0x%08X] "
630                          "magic2_hash[0x%08X %s 0x%08X]\n",
631                          name, hash_alg,
632                          header.magic1_hash,
633                          (header.magic1_hash == magic1) ? "==" : "!=",
634                          magic1,
635                          header.magic2_hash,
636                          (header.magic2_hash == magic2) ? "==" : "!=",
637                          magic2));
638                 errno = EINVAL;
639                 goto fail;
640         }
641
642         /* Is it already in the open list?  If so, fail. */
643         if (tdb_already_open(tdb->device, tdb->inode)) {
644                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
645                          "%s (%d,%d) is already open in this process\n",
646                          name, (int)tdb->device, (int)tdb->inode));
647                 errno = EBUSY;
648                 goto fail;
649         }
650
651         /*
652          * We had tdb_mmap(tdb) here before,
653          * but we need to use tdb_fstat(),
654          * which is triggered from tdb_oob() before calling tdb_mmap().
655          * As this skips tdb->hdr_ofs.
656          */
657         tdb->map_size = 0;
658         ret = tdb->methods->tdb_oob(tdb, 0, 1, 0);
659         if (ret == -1) {
660                 errno = EIO;
661                 goto fail;
662         }
663
664         if (tdb->feature_flags & TDB_FEATURE_FLAG_MUTEX) {
665                 if (!(tdb->flags & TDB_NOLOCK)) {
666                         ret = tdb_mutex_mmap(tdb);
667                         if (ret != 0) {
668                                 goto fail;
669                         }
670                 }
671         }
672
673         if (tdb->hash_size > UINT32_MAX/4) {
674                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
675                          "hash size %"PRIu32" too large\n", tdb->hash_size));
676                 errno = EINVAL;
677                 goto fail;
678         }
679
680         ret = tdb->methods->tdb_oob(tdb, FREELIST_TOP, 4*tdb->hash_size, 1);
681         if (ret == -1) {
682                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
683                          "hash size %"PRIu32" does not fit\n", tdb->hash_size));
684                 errno = EINVAL;
685                 goto fail;
686         }
687
688         if (locked) {
689                 if (tdb_nest_unlock(tdb, ACTIVE_LOCK, F_WRLCK, false) == -1) {
690                         TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
691                                  "failed to release ACTIVE_LOCK on %s: %s\n",
692                                  name, strerror(errno)));
693                         goto fail;
694                 }
695
696
697         }
698
699         if (locked || (tdb_flags & TDB_CLEAR_IF_FIRST)) {
700                 /*
701                  * We always need to do this if the CLEAR_IF_FIRST
702                  * flag is set, even if we didn't get the initial
703                  * exclusive lock as we need to let all other users
704                  * know we're using it.
705                  */
706
707                 ret = tdb_nest_lock(tdb, ACTIVE_LOCK, F_RDLCK, TDB_LOCK_WAIT);
708                 if (ret == -1) {
709                         goto fail;
710                 }
711         }
712
713         /* if needed, run recovery */
714         if (tdb_transaction_recover(tdb) == -1) {
715                 goto fail;
716         }
717
718 #ifdef TDB_TRACE
719         {
720                 char tracefile[strlen(name) + 32];
721
722                 snprintf(tracefile, sizeof(tracefile),
723                          "%s.trace.%li", name, (long)getpid());
724                 tdb->tracefd = open(tracefile, O_WRONLY|O_CREAT|O_EXCL, 0600);
725                 if (tdb->tracefd >= 0) {
726                         tdb_enable_seqnum(tdb);
727                         tdb_trace_open(tdb, "tdb_open", hash_size, tdb_flags,
728                                        open_flags);
729                 } else
730                         TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to open trace file %s!\n", tracefile));
731         }
732 #endif
733
734  internal:
735         /* Internal (memory-only) databases skip all the code above to
736          * do with disk files, and resume here by releasing their
737          * open lock and hooking into the active list. */
738         if (tdb_nest_unlock(tdb, OPEN_LOCK, F_WRLCK, false) == -1) {
739                 goto fail;
740         }
741         tdb->next = tdbs;
742         tdbs = tdb;
743         errno = orig_errno;
744         return tdb;
745
746  fail:
747         { int save_errno = errno;
748
749         if (!tdb)
750                 return NULL;
751
752 #ifdef TDB_TRACE
753         close(tdb->tracefd);
754 #endif
755         if (tdb->map_ptr) {
756                 if (tdb->flags & TDB_INTERNAL)
757                         SAFE_FREE(tdb->map_ptr);
758                 else
759                         tdb_munmap(tdb);
760         }
761         if (tdb->fd != -1)
762                 if (close(tdb->fd) != 0)
763                         TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to close tdb->fd on error!\n"));
764         SAFE_FREE(tdb->lockrecs);
765         SAFE_FREE(tdb->name);
766         SAFE_FREE(tdb);
767         errno = save_errno;
768         return NULL;
769         }
770 }
771
772 /*
773  * Set the maximum number of dead records per hash chain
774  */
775
776 _PUBLIC_ void tdb_set_max_dead(struct tdb_context *tdb, int max_dead)
777 {
778         tdb->max_dead_records = max_dead;
779 }
780
781 /**
782  * Close a database.
783  *
784  * @returns -1 for error; 0 for success.
785  **/
786 _PUBLIC_ int tdb_close(struct tdb_context *tdb)
787 {
788         struct tdb_context **i;
789         int ret = 0;
790
791         if (tdb->transaction) {
792                 tdb_transaction_cancel(tdb);
793         }
794         tdb_trace(tdb, "tdb_close");
795
796         if (tdb->map_ptr) {
797                 if (tdb->flags & TDB_INTERNAL)
798                         SAFE_FREE(tdb->map_ptr);
799                 else
800                         tdb_munmap(tdb);
801         }
802
803         tdb_mutex_munmap(tdb);
804
805         SAFE_FREE(tdb->name);
806         if (tdb->fd != -1) {
807                 ret = close(tdb->fd);
808                 tdb->fd = -1;
809         }
810         SAFE_FREE(tdb->lockrecs);
811
812         /* Remove from contexts list */
813         for (i = &tdbs; *i; i = &(*i)->next) {
814                 if (*i == tdb) {
815                         *i = tdb->next;
816                         break;
817                 }
818         }
819
820 #ifdef TDB_TRACE
821         close(tdb->tracefd);
822 #endif
823         memset(tdb, 0, sizeof(*tdb));
824         SAFE_FREE(tdb);
825
826         return ret;
827 }
828
829 /* register a loging function */
830 _PUBLIC_ void tdb_set_logging_function(struct tdb_context *tdb,
831                                        const struct tdb_logging_context *log_ctx)
832 {
833         tdb->log = *log_ctx;
834 }
835
836 _PUBLIC_ void *tdb_get_logging_private(struct tdb_context *tdb)
837 {
838         return tdb->log.log_private;
839 }
840
841 static int tdb_reopen_internal(struct tdb_context *tdb, bool active_lock)
842 {
843 #if !defined(LIBREPLACE_PREAD_NOT_REPLACED) || \
844         !defined(LIBREPLACE_PWRITE_NOT_REPLACED)
845         struct stat st;
846 #endif
847
848         if (tdb->flags & TDB_INTERNAL) {
849                 return 0; /* Nothing to do. */
850         }
851
852         if (tdb_have_extra_locks(tdb)) {
853                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed with locks held\n"));
854                 goto fail;
855         }
856
857         if (tdb->transaction != 0) {
858                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed inside a transaction\n"));
859                 goto fail;
860         }
861
862 /* If we have real pread & pwrite, we can skip reopen. */
863 #if !defined(LIBREPLACE_PREAD_NOT_REPLACED) || \
864         !defined(LIBREPLACE_PWRITE_NOT_REPLACED)
865         if (tdb_munmap(tdb) != 0) {
866                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: munmap failed (%s)\n", strerror(errno)));
867                 goto fail;
868         }
869         if (close(tdb->fd) != 0)
870                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: WARNING closing tdb->fd failed!\n"));
871         tdb->fd = open(tdb->name, tdb->open_flags & ~(O_CREAT|O_TRUNC), 0);
872         if (tdb->fd == -1) {
873                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: open failed (%s)\n", strerror(errno)));
874                 goto fail;
875         }
876         /*
877          * We only use st.st_dev and st.st_ino from the raw fstat()
878          * call, everything else needs to use tdb_fstat() in order
879          * to skip tdb->hdr_ofs!
880          */
881         if (fstat(tdb->fd, &st) != 0) {
882                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: fstat failed (%s)\n", strerror(errno)));
883                 goto fail;
884         }
885         if (st.st_ino != tdb->inode || st.st_dev != tdb->device) {
886                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: file dev/inode has changed!\n"));
887                 goto fail;
888         }
889         ZERO_STRUCT(st);
890
891         /*
892          * We had tdb_mmap(tdb) here before,
893          * but we need to use tdb_fstat(),
894          * which is triggered from tdb_oob() before calling tdb_mmap().
895          * As this skips tdb->hdr_ofs.
896          */
897         tdb->map_size = 0;
898         if (tdb->methods->tdb_oob(tdb, 0, 1, 0) != 0) {
899                 goto fail;
900         }
901 #endif /* fake pread or pwrite */
902
903         /* We may still think we hold the active lock. */
904         tdb->num_lockrecs = 0;
905         SAFE_FREE(tdb->lockrecs);
906         tdb->lockrecs_array_length = 0;
907
908         if (active_lock && tdb_nest_lock(tdb, ACTIVE_LOCK, F_RDLCK, TDB_LOCK_WAIT) == -1) {
909                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: failed to obtain active lock\n"));
910                 goto fail;
911         }
912
913         return 0;
914
915 fail:
916         tdb_close(tdb);
917         return -1;
918 }
919
920 /* reopen a tdb - this can be used after a fork to ensure that we have an independent
921    seek pointer from our parent and to re-establish locks */
922 _PUBLIC_ int tdb_reopen(struct tdb_context *tdb)
923 {
924         bool active_lock;
925         active_lock = (tdb->flags & (TDB_CLEAR_IF_FIRST|TDB_MUTEX_LOCKING));
926
927         return tdb_reopen_internal(tdb, active_lock);
928 }
929
930 /* reopen all tdb's */
931 _PUBLIC_ int tdb_reopen_all(int parent_longlived)
932 {
933         struct tdb_context *tdb;
934
935         for (tdb=tdbs; tdb; tdb = tdb->next) {
936                 bool active_lock;
937
938                 active_lock =
939                         (tdb->flags & (TDB_CLEAR_IF_FIRST|TDB_MUTEX_LOCKING));
940
941                 /*
942                  * If the parent is longlived (ie. a
943                  * parent daemon architecture), we know
944                  * it will keep it's active lock on a
945                  * tdb opened with CLEAR_IF_FIRST. Thus
946                  * for child processes we don't have to
947                  * add an active lock. This is essential
948                  * to improve performance on systems that
949                  * keep POSIX locks as a non-scalable data
950                  * structure in the kernel.
951                  */
952                 if (parent_longlived) {
953                         /* Ensure no clear-if-first. */
954                         active_lock = false;
955                 }
956
957                 if (tdb_reopen_internal(tdb, active_lock) != 0)
958                         return -1;
959         }
960
961         return 0;
962 }