5 TDB version 2: trivial database library
7 Copyright (C) Andrew Tridgell 1999-2004
8 Copyright (C) Rusty Russell 2010-2011
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/>.
34 #if HAVE_FILE_OFFSET_BITS
35 #define _FILE_OFFSET_BITS 64
38 #include <sys/types.h>
41 /* For sig_atomic_t. */
50 #include <ccan/compiler/compiler.h>
51 #include <ccan/typesafe_cb/typesafe_cb.h>
52 #include <ccan/cast/cast.h>
58 * tdb_open - open a database file
59 * @name: the file name (can be NULL if flags contains TDB_INTERNAL)
60 * @tdb_flags: options for this database
61 * @open_flags: flags argument for tdb's open() call.
62 * @mode: mode argument for tdb's open() call.
63 * @attributes: linked list of extra attributes for this tdb.
65 * This call opens (and potentially creates) a database file.
66 * Multiple processes can have the TDB file open at once.
68 * On failure it will return NULL, and set errno: it may also call
69 * any log attribute found in @attributes.
74 struct tdb_context *tdb_open(const char *name, int tdb_flags,
75 int open_flags, mode_t mode,
76 union tdb_attribute *attributes);
79 /* flags for tdb_open() */
80 #define TDB_DEFAULT 0 /* just a readability place holder */
81 #define TDB_INTERNAL 2 /* don't store on disk */
82 #define TDB_NOLOCK 4 /* don't do any locking */
83 #define TDB_NOMMAP 8 /* don't use mmap */
84 #define TDB_CONVERT 16 /* convert endian */
85 #define TDB_NOSYNC 64 /* don't use synchronous transactions */
86 #define TDB_SEQNUM 128 /* maintain a sequence number */
87 #define TDB_ALLOW_NESTING 256 /* fake nested transactions */
88 #define TDB_RDONLY 512 /* implied by O_RDONLY */
91 * tdb_close - close and free a tdb.
92 * @tdb: the tdb context returned from tdb_open()
94 * This always succeeds, in that @tdb is unusable after this call. But if
95 * some unexpected error occurred while closing, it will return non-zero
96 * (the only clue as to cause will be via the log attribute).
98 int tdb_close(struct tdb_context *tdb);
101 * struct tdb_data - representation of keys or values.
102 * @dptr: the data pointer
103 * @dsize: the size of the data pointed to by dptr.
105 * This is the "blob" representation of keys and data used by TDB.
107 typedef struct tdb_data {
113 * enum TDB_ERROR - error returns for TDB
119 TDB_SUCCESS = 0, /* No error. */
120 TDB_ERR_CORRUPT = -1, /* We read the db, and it was bogus. */
121 TDB_ERR_IO = -2, /* We couldn't read/write the db. */
122 TDB_ERR_LOCK = -3, /* Locking failed. */
123 TDB_ERR_OOM = -4, /* Out of Memory. */
124 TDB_ERR_EXISTS = -5, /* The key already exists. */
125 TDB_ERR_NOEXIST = -6, /* The key does not exist. */
126 TDB_ERR_EINVAL = -7, /* You're using it wrong. */
127 TDB_ERR_RDONLY = -8, /* The database is read-only. */
128 TDB_ERR_LAST = TDB_ERR_RDONLY
132 * tdb_store - store a key/value pair in a tdb.
133 * @tdb: the tdb context returned from tdb_open()
135 * @dbuf: the data to associate with the key.
136 * @flag: TDB_REPLACE, TDB_INSERT or TDB_MODIFY.
138 * This inserts (or overwrites) a key/value pair in the TDB. If flag
139 * is TDB_REPLACE, it doesn't matter whether the key exists or not;
140 * TDB_INSERT means it must not exist (returns TDB_ERR_EXISTS otherwise),
141 * and TDB_MODIFY means it must exist (returns TDB_ERR_NOEXIST otherwise).
143 * On success, this returns TDB_SUCCESS.
146 * tdb_fetch, tdb_transaction_start, tdb_append, tdb_delete.
148 enum TDB_ERROR tdb_store(struct tdb_context *tdb,
150 struct tdb_data dbuf,
153 /* flags to tdb_store() */
154 #define TDB_REPLACE 1 /* A readability place holder */
155 #define TDB_INSERT 2 /* Don't overwrite an existing entry */
156 #define TDB_MODIFY 3 /* Don't create an existing entry */
159 * tdb_fetch - fetch a value from a tdb.
160 * @tdb: the tdb context returned from tdb_open()
162 * @data: pointer to data.
164 * This looks up a key in the database and sets it in @data.
166 * If it returns TDB_SUCCESS, the key was found: it is your
167 * responsibility to call free() on @data->dptr.
169 * Otherwise, it returns an error (usually, TDB_ERR_NOEXIST) and @data is
172 enum TDB_ERROR tdb_fetch(struct tdb_context *tdb, struct tdb_data key,
173 struct tdb_data *data);
176 * tdb_errorstr - map the tdb error onto a constant readable string
177 * @ecode: the enum TDB_ERROR to map.
179 * This is useful for displaying errors to users.
181 const char *tdb_errorstr(enum TDB_ERROR ecode);
184 * tdb_append - append a value to a key/value pair in a tdb.
185 * @tdb: the tdb context returned from tdb_open()
187 * @dbuf: the data to append.
189 * This is equivalent to fetching a record, reallocating .dptr to add the
190 * data, and writing it back, only it's much more efficient. If the key
191 * doesn't exist, it's equivalent to tdb_store (with an additional hint that
192 * you expect to expand the record in future).
195 * tdb_fetch(), tdb_store()
197 enum TDB_ERROR tdb_append(struct tdb_context *tdb,
198 struct tdb_data key, struct tdb_data dbuf);
201 * tdb_delete - delete a key from a tdb.
202 * @tdb: the tdb context returned from tdb_open()
203 * @key: the key to delete.
205 * Returns TDB_SUCCESS on success, or an error (usually TDB_ERR_NOEXIST).
208 * tdb_fetch(), tdb_store()
210 enum TDB_ERROR tdb_delete(struct tdb_context *tdb, struct tdb_data key);
213 * tdb_exists - does a key exist in the database?
214 * @tdb: the tdb context returned from tdb_open()
215 * @key: the key to search for.
217 * Returns true if it exists, or false if it doesn't or any other error.
219 bool tdb_exists(struct tdb_context *tdb, TDB_DATA key);
222 * tdb_deq - are struct tdb_data equal?
223 * @a: one struct tdb_data
224 * @b: another struct tdb_data
226 static inline bool tdb_deq(struct tdb_data a, struct tdb_data b)
228 return a.dsize == b.dsize && memcmp(a.dptr, b.dptr, a.dsize) == 0;
232 * tdb_mkdata - make a struct tdb_data from const data
233 * @p: the constant pointer
236 * As the dptr member of struct tdb_data is not constant, you need to
237 * cast it. This function keeps thost casts in one place, as well as
238 * suppressing the warning some compilers give when casting away a
239 * qualifier (eg. gcc with -Wcast-qual)
241 static inline struct tdb_data tdb_mkdata(const void *p, size_t len)
244 d.dptr = cast_const(void *, p);
250 * tdb_transaction_start - start a transaction
251 * @tdb: the tdb context returned from tdb_open()
253 * This begins a series of atomic operations. Other processes will be able
254 * to read the tdb, but not alter it (they will block), nor will they see
255 * any changes until tdb_transaction_commit() is called.
257 * Note that if the TDB_ALLOW_NESTING flag is set, a tdb_transaction_start()
258 * within a transaction will succeed, but it's not a real transaction:
259 * (1) An inner transaction which is committed is not actually committed until
260 * the outer transaction is; if the outer transaction is cancelled, the
261 * inner ones are discarded.
262 * (2) tdb_transaction_cancel() marks the outer transaction as having an error,
263 * so the final tdb_transaction_commit() will fail.
264 * (3) the outer transaction will see the results of the inner transaction.
267 * tdb_transaction_cancel, tdb_transaction_commit.
269 enum TDB_ERROR tdb_transaction_start(struct tdb_context *tdb);
272 * tdb_transaction_cancel - abandon a transaction
273 * @tdb: the tdb context returned from tdb_open()
275 * This aborts a transaction, discarding any changes which were made.
276 * tdb_close() does this implicitly.
278 void tdb_transaction_cancel(struct tdb_context *tdb);
281 * tdb_transaction_commit - commit a transaction
282 * @tdb: the tdb context returned from tdb_open()
284 * This completes a transaction, writing any changes which were made.
286 * fsync() is used to commit the transaction (unless TDB_NOSYNC is set),
287 * making it robust against machine crashes, but very slow compared to
288 * other TDB operations.
290 * A failure can only be caused by unexpected errors (eg. I/O or
291 * memory); this is no point looping on transaction failure.
294 * tdb_transaction_prepare_commit()
296 enum TDB_ERROR tdb_transaction_commit(struct tdb_context *tdb);
299 * tdb_transaction_prepare_commit - prepare to commit a transaction
300 * @tdb: the tdb context returned from tdb_open()
302 * This ensures we have the resources to commit a transaction (using
303 * tdb_transaction_commit): if this succeeds then a transaction will only
304 * fail if the write() or fsync() calls fail.
306 * If this fails you must still call tdb_transaction_cancel() to cancel
310 * tdb_transaction_commit()
312 enum TDB_ERROR tdb_transaction_prepare_commit(struct tdb_context *tdb);
315 * tdb_traverse - traverse a TDB
316 * @tdb: the tdb context returned from tdb_open()
317 * @fn: the function to call for every key/value pair (or NULL)
318 * @p: the pointer to hand to @f
320 * This walks the TDB until all they keys have been traversed, or @fn
321 * returns non-zero. If the traverse function or other processes are
322 * changing data or adding or deleting keys, the traverse may be
323 * unreliable: keys may be skipped or (rarely) visited twice.
325 * There is one specific exception: the special case of deleting the
326 * current key does not undermine the reliability of the traversal.
328 * On success, returns the number of keys iterated. On error returns
329 * a negative enum TDB_ERROR value.
331 #define tdb_traverse(tdb, fn, p) \
332 tdb_traverse_(tdb, typesafe_cb_preargs(int, void *, (fn), (p), \
333 struct tdb_context *, \
334 TDB_DATA, TDB_DATA), (p))
336 int64_t tdb_traverse_(struct tdb_context *tdb,
337 int (*fn)(struct tdb_context *,
338 TDB_DATA, TDB_DATA, void *), void *p);
341 * tdb_parse_record - operate directly on data in the database.
342 * @tdb: the tdb context returned from tdb_open()
343 * @key: the key whose record we should hand to @parse
344 * @parse: the function to call for the data
345 * @data: the private pointer to hand to @parse (types must match).
347 * This avoids a copy for many cases, by handing you a pointer into
348 * the memory-mapped database. It also locks the record to prevent
349 * other accesses at the same time.
351 * Do not alter the data handed to parse()!
353 #define tdb_parse_record(tdb, key, parse, data) \
354 tdb_parse_record_((tdb), (key), \
355 typesafe_cb_preargs(enum TDB_ERROR, void *, \
357 TDB_DATA, TDB_DATA), (data))
359 enum TDB_ERROR tdb_parse_record_(struct tdb_context *tdb,
361 enum TDB_ERROR (*parse)(TDB_DATA k,
367 * tdb_get_seqnum - get a database sequence number
368 * @tdb: the tdb context returned from tdb_open()
370 * This returns a sequence number: any change to the database from a
371 * tdb context opened with the TDB_SEQNUM flag will cause that number
372 * to increment. Note that the incrementing is unreliable (it is done
373 * without locking), so this is only useful as an optimization.
375 * For example, you may have a regular database backup routine which
376 * does not operate if the sequence number is unchanged. In the
377 * unlikely event of a failed increment, it will be backed up next
380 * Returns an enum TDB_ERROR (ie. negative) on error.
382 int64_t tdb_get_seqnum(struct tdb_context *tdb);
385 * tdb_firstkey - get the "first" key in a TDB
386 * @tdb: the tdb context returned from tdb_open()
387 * @key: pointer to key.
389 * This returns an arbitrary key in the database; with tdb_nextkey() it allows
390 * open-coded traversal of the database, though it is slightly less efficient
393 * It is your responsibility to free @key->dptr on success.
395 * Returns TDB_ERR_NOEXIST if the database is empty.
397 enum TDB_ERROR tdb_firstkey(struct tdb_context *tdb, struct tdb_data *key);
400 * tdb_nextkey - get the "next" key in a TDB
401 * @tdb: the tdb context returned from tdb_open()
402 * @key: a key returned by tdb_firstkey() or tdb_nextkey().
404 * This returns another key in the database; it will free @key.dptr for
407 * Returns TDB_ERR_NOEXIST if there are no more keys.
409 enum TDB_ERROR tdb_nextkey(struct tdb_context *tdb, struct tdb_data *key);
412 * tdb_chainlock - lock a record in the TDB
413 * @tdb: the tdb context returned from tdb_open()
414 * @key: the key to lock.
416 * This prevents any access occurring to a group of keys including @key,
417 * even if @key does not exist. This allows primitive atomic updates of
418 * records without using transactions.
420 * You cannot begin a transaction while holding a tdb_chainlock(), nor can
421 * you do any operations on any other keys in the database. This also means
422 * that you cannot hold more than one tdb_chainlock() at a time.
427 enum TDB_ERROR tdb_chainlock(struct tdb_context *tdb, TDB_DATA key);
430 * tdb_chainunlock - unlock a record in the TDB
431 * @tdb: the tdb context returned from tdb_open()
432 * @key: the key to unlock.
434 * The key must have previously been locked by tdb_chainlock().
436 void tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key);
439 * tdb_chainlock_read - lock a record in the TDB, for reading
440 * @tdb: the tdb context returned from tdb_open()
441 * @key: the key to lock.
443 * This prevents any changes from occurring to a group of keys including @key,
444 * even if @key does not exist. This allows primitive atomic updates of
445 * records without using transactions.
447 * You cannot begin a transaction while holding a tdb_chainlock_read(), nor can
448 * you do any operations on any other keys in the database. This also means
449 * that you cannot hold more than one tdb_chainlock()/read() at a time.
454 enum TDB_ERROR tdb_chainlock_read(struct tdb_context *tdb, TDB_DATA key);
457 * tdb_chainunlock_read - unlock a record in the TDB for reading
458 * @tdb: the tdb context returned from tdb_open()
459 * @key: the key to unlock.
461 * The key must have previously been locked by tdb_chainlock_read().
463 void tdb_chainunlock_read(struct tdb_context *tdb, TDB_DATA key);
466 * tdb_lockall - lock the entire TDB
467 * @tdb: the tdb context returned from tdb_open()
469 * You cannot hold a tdb_chainlock while calling this. It nests, so you
470 * must call tdb_unlockall as many times as you call tdb_lockall.
472 enum TDB_ERROR tdb_lockall(struct tdb_context *tdb);
475 * tdb_unlockall - unlock the entire TDB
476 * @tdb: the tdb context returned from tdb_open()
478 void tdb_unlockall(struct tdb_context *tdb);
481 * tdb_lockall_read - lock the entire TDB for reading
482 * @tdb: the tdb context returned from tdb_open()
484 * This prevents others writing to the database, eg. tdb_delete, tdb_store,
485 * tdb_append, but not tdb_fetch.
487 * You cannot hold a tdb_chainlock while calling this. It nests, so you
488 * must call tdb_unlockall_read as many times as you call tdb_lockall_read.
490 enum TDB_ERROR tdb_lockall_read(struct tdb_context *tdb);
493 * tdb_unlockall_read - unlock the entire TDB for reading
494 * @tdb: the tdb context returned from tdb_open()
496 void tdb_unlockall_read(struct tdb_context *tdb);
499 * tdb_wipe_all - wipe the database clean
500 * @tdb: the tdb context returned from tdb_open()
502 * Completely erase the database. This is faster than iterating through
503 * each key and doing tdb_delete.
505 enum TDB_ERROR tdb_wipe_all(struct tdb_context *tdb);
508 * tdb_check - check a TDB for consistency
509 * @tdb: the tdb context returned from tdb_open()
510 * @check: function to check each key/data pair (or NULL)
511 * @data: argument for @check, must match type.
513 * This performs a consistency check of the open database, optionally calling
514 * a check() function on each record so you can do your own data consistency
515 * checks as well. If check() returns an error, that is returned from
518 * Returns TDB_SUCCESS or an error.
520 #define tdb_check(tdb, check, data) \
521 tdb_check_((tdb), typesafe_cb_preargs(enum TDB_ERROR, void *, \
527 enum TDB_ERROR tdb_check_(struct tdb_context *tdb,
528 enum TDB_ERROR (*check)(struct tdb_data k,
534 * tdb_error - get the last error (not threadsafe)
535 * @tdb: the tdb context returned from tdb_open()
537 * Returns the last error returned by a TDB function.
539 * This makes porting from TDB1 easier, but note that the last error is not
540 * reliable in threaded programs.
542 enum TDB_ERROR tdb_error(struct tdb_context *tdb);
545 * enum tdb_summary_flags - flags for tdb_summary.
547 enum tdb_summary_flags {
548 TDB_SUMMARY_HISTOGRAMS = 1 /* Draw graphs in the summary. */
552 * tdb_summary - return a string describing the TDB state
553 * @tdb: the tdb context returned from tdb_open()
554 * @flags: flags to control the summary output.
555 * @summary: pointer to string to allocate.
557 * This returns a developer-readable string describing the overall
558 * state of the tdb, such as the percentage used and sizes of records.
559 * It is designed to provide information about the tdb at a glance
560 * without displaying any keys or data in the database.
562 * On success, sets @summary to point to a malloc()'ed nul-terminated
563 * multi-line string. It is your responsibility to free() it.
565 enum TDB_ERROR tdb_summary(struct tdb_context *tdb,
566 enum tdb_summary_flags flags,
571 * tdb_get_flags - return the flags for a tdb
572 * @tdb: the tdb context returned from tdb_open()
574 * This returns the flags on the current tdb. Some of these are caused by
575 * the flags argument to tdb_open(), others (such as TDB_CONVERT) are
578 unsigned int tdb_get_flags(struct tdb_context *tdb);
581 * tdb_add_flag - set a flag for a tdb
582 * @tdb: the tdb context returned from tdb_open()
583 * @flag: one of TDB_NOLOCK, TDB_NOMMAP, TDB_NOSYNC or TDB_ALLOW_NESTING.
585 * You can use this to set a flag on the TDB. You cannot set these flags
586 * on a TDB_INTERNAL tdb.
588 void tdb_add_flag(struct tdb_context *tdb, unsigned flag);
591 * tdb_remove_flag - unset a flag for a tdb
592 * @tdb: the tdb context returned from tdb_open()
593 * @flag: one of TDB_NOLOCK, TDB_NOMMAP, TDB_NOSYNC or TDB_ALLOW_NESTING.
595 * You can use this to clear a flag on the TDB. You cannot clear flags
596 * on a TDB_INTERNAL tdb.
598 void tdb_remove_flag(struct tdb_context *tdb, unsigned flag);
601 * enum tdb_attribute_type - descriminator for union tdb_attribute.
603 enum tdb_attribute_type {
604 TDB_ATTRIBUTE_LOG = 0,
605 TDB_ATTRIBUTE_HASH = 1,
606 TDB_ATTRIBUTE_SEED = 2,
607 TDB_ATTRIBUTE_STATS = 3,
608 TDB_ATTRIBUTE_OPENHOOK = 4,
609 TDB_ATTRIBUTE_FLOCK = 5
613 * tdb_get_attribute - get an attribute for an existing tdb
614 * @tdb: the tdb context returned from tdb_open()
615 * @attr: the union tdb_attribute to set.
617 * This gets an attribute from a TDB which has previously been set (or
618 * may return the default values). Set @attr.base.attr to the
619 * attribute type you want get.
621 enum TDB_ERROR tdb_get_attribute(struct tdb_context *tdb,
622 union tdb_attribute *attr);
625 * tdb_set_attribute - set an attribute for an existing tdb
626 * @tdb: the tdb context returned from tdb_open()
627 * @attr: the union tdb_attribute to set.
629 * This sets an attribute on a TDB, overriding any previous attribute
630 * of the same type. It returns TDB_ERR_EINVAL if the attribute is
631 * unknown or invalid.
633 * Note that TDB_ATTRIBUTE_HASH, TDB_ATTRIBUTE_SEED and
634 * TDB_ATTRIBUTE_OPENHOOK cannot currently be set after tdb_open.
636 enum TDB_ERROR tdb_set_attribute(struct tdb_context *tdb,
637 const union tdb_attribute *attr);
640 * tdb_unset_attribute - reset an attribute for an existing tdb
641 * @tdb: the tdb context returned from tdb_open()
642 * @type: the attribute type to unset.
644 * This unsets an attribute on a TDB, returning it to the defaults
645 * (where applicable).
647 * Note that it only makes sense for TDB_ATTRIBUTE_LOG and TDB_ATTRIBUTE_FLOCK
650 void tdb_unset_attribute(struct tdb_context *tdb,
651 enum tdb_attribute_type type);
654 * tdb_name - get the name of a tdb
655 * @tdb: the tdb context returned from tdb_open()
657 * This returns a copy of the name string, made at tdb_open() time. If that
658 * argument was NULL (possible for a TDB_INTERNAL db) this will return NULL.
660 * This is mostly useful for logging.
662 const char *tdb_name(const struct tdb_context *tdb);
665 * tdb_fd - get the file descriptor of a tdb
666 * @tdb: the tdb context returned from tdb_open()
668 * This returns the file descriptor for the underlying database file, or -1
671 int tdb_fd(const struct tdb_context *tdb);
674 * struct tdb_attribute_base - common fields for all tdb attributes.
676 struct tdb_attribute_base {
677 enum tdb_attribute_type attr;
678 union tdb_attribute *next;
682 * enum tdb_log_level - log levels for tdb_attribute_log
683 * @TDB_LOG_ERROR: used to log unrecoverable errors such as I/O errors
684 * or internal consistency failures.
685 * @TDB_LOG_USE_ERROR: used to log usage errors such as invalid parameters
686 * or writing to a read-only database.
687 * @TDB_LOG_WARNING: used for informational messages on issues which
688 * are unusual but handled by TDB internally, such
689 * as a failure to mmap or failure to open /dev/urandom.
698 * struct tdb_attribute_log - log function attribute
700 * This attribute provides a hook for you to log errors.
702 struct tdb_attribute_log {
703 struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_LOG */
704 void (*fn)(struct tdb_context *tdb,
705 enum tdb_log_level level,
706 enum TDB_ERROR ecode,
713 * struct tdb_attribute_hash - hash function attribute
715 * This attribute allows you to provide an alternative hash function.
716 * This hash function will be handed keys from the database; it will also
717 * be handed the 8-byte TDB_HASH_MAGIC value for checking the header (the
718 * tdb_open() will fail if the hash value doesn't match the header).
720 * Note that if your hash function gives different results on
721 * different machine endians, your tdb will no longer work across
722 * different architectures!
724 struct tdb_attribute_hash {
725 struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_HASH */
726 uint64_t (*fn)(const void *key, size_t len, uint64_t seed,
732 * struct tdb_attribute_seed - hash function seed attribute
734 * The hash function seed is normally taken from /dev/urandom (or equivalent)
735 * but can be set manually here. This is mainly for testing purposes.
737 struct tdb_attribute_seed {
738 struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_SEED */
743 * struct tdb_attribute_stats - tdb operational statistics
745 * This attribute records statistics of various low-level TDB operations.
746 * This can be used to assist performance evaluation. This is only
747 * useful for tdb_get_attribute().
749 * New fields will be added at the end, hence the "size" argument which
750 * indicates how large your structure is: it must be filled in before
751 * calling tdb_get_attribute(), which will overwrite it with the size
754 struct tdb_attribute_stats {
755 struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_STATS */
756 size_t size; /* = sizeof(struct tdb_attribute_stats) */
758 uint64_t alloc_subhash;
759 uint64_t alloc_chain;
760 uint64_t alloc_bucket_exact;
761 uint64_t alloc_bucket_max;
762 uint64_t alloc_leftover;
763 uint64_t alloc_coalesce_tried;
764 uint64_t alloc_coalesce_iterate_clash;
765 uint64_t alloc_coalesce_lockfail;
766 uint64_t alloc_coalesce_race;
767 uint64_t alloc_coalesce_succeeded;
768 uint64_t alloc_coalesce_num_merged;
770 uint64_t compare_wrong_bucket;
771 uint64_t compare_wrong_offsetbits;
772 uint64_t compare_wrong_keylen;
773 uint64_t compare_wrong_rechash;
774 uint64_t compare_wrong_keycmp;
775 uint64_t transactions;
776 uint64_t transaction_cancel;
777 uint64_t transaction_nest;
778 uint64_t transaction_expand_file;
779 uint64_t transaction_read_direct;
780 uint64_t transaction_read_direct_fail;
781 uint64_t transaction_write_direct;
782 uint64_t transaction_write_direct_fail;
786 uint64_t lock_lowlevel;
787 uint64_t lock_nonblock;
788 uint64_t lock_nonblock_fail;
792 * struct tdb_attribute_openhook - tdb special effects hook for open
794 * This attribute contains a function to call once we have the OPEN_LOCK
795 * for the tdb, but before we've examined its contents. If this succeeds,
796 * the tdb will be populated if it's then zero-length.
798 * This is a hack to allow support for TDB1-style TDB_CLEAR_IF_FIRST
801 struct tdb_attribute_openhook {
802 struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_OPENHOOK */
803 enum TDB_ERROR (*fn)(int fd, void *data);
808 * struct tdb_attribute_flock - tdb special effects hook for file locking
810 * This attribute contains function to call to place locks on a file; it can
811 * be used to support non-blocking operations or lock proxying.
813 * They should return 0 on success, -1 on failure and set errno.
815 * An error will be logged on error if errno is neither EAGAIN nor EINTR
816 * (normally it would only return EAGAIN if waitflag is false, and
817 * loop internally on EINTR).
819 struct tdb_attribute_flock {
820 struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_FLOCK */
821 int (*lock)(int fd,int rw, off_t off, off_t len, bool waitflag, void *);
822 int (*unlock)(int fd, int rw, off_t off, off_t len, void *);
827 * union tdb_attribute - tdb attributes.
829 * This represents all the known attributes.
832 * struct tdb_attribute_log, struct tdb_attribute_hash,
833 * struct tdb_attribute_seed, struct tdb_attribute_stats,
834 * struct tdb_attribute_openhook, struct tdb_attribute_flock.
836 union tdb_attribute {
837 struct tdb_attribute_base base;
838 struct tdb_attribute_log log;
839 struct tdb_attribute_hash hash;
840 struct tdb_attribute_seed seed;
841 struct tdb_attribute_stats stats;
842 struct tdb_attribute_openhook openhook;
843 struct tdb_attribute_flock flock;