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 */
90 * tdb_close - close and free a tdb.
91 * @tdb: the tdb context returned from tdb_open()
93 * This always succeeds, in that @tdb is unusable after this call. But if
94 * some unexpected error occurred while closing, it will return non-zero
95 * (the only clue as to cause will be via the log attribute).
97 int tdb_close(struct tdb_context *tdb);
100 * struct tdb_data - representation of keys or values.
101 * @dptr: the data pointer
102 * @dsize: the size of the data pointed to by dptr.
104 * This is the "blob" representation of keys and data used by TDB.
106 typedef struct tdb_data {
112 * enum TDB_ERROR - error returns for TDB
118 TDB_SUCCESS = 0, /* No error. */
119 TDB_ERR_CORRUPT = -1, /* We read the db, and it was bogus. */
120 TDB_ERR_IO = -2, /* We couldn't read/write the db. */
121 TDB_ERR_LOCK = -3, /* Locking failed. */
122 TDB_ERR_OOM = -4, /* Out of Memory. */
123 TDB_ERR_EXISTS = -5, /* The key already exists. */
124 TDB_ERR_NOEXIST = -6, /* The key does not exist. */
125 TDB_ERR_EINVAL = -7, /* You're using it wrong. */
126 TDB_ERR_RDONLY = -8, /* The database is read-only. */
127 TDB_ERR_LAST = TDB_ERR_RDONLY
131 * tdb_store - store a key/value pair in a tdb.
132 * @tdb: the tdb context returned from tdb_open()
134 * @dbuf: the data to associate with the key.
135 * @flag: TDB_REPLACE, TDB_INSERT or TDB_MODIFY.
137 * This inserts (or overwrites) a key/value pair in the TDB. If flag
138 * is TDB_REPLACE, it doesn't matter whether the key exists or not;
139 * TDB_INSERT means it must not exist (returns TDB_ERR_EXISTS otherwise),
140 * and TDB_MODIFY means it must exist (returns TDB_ERR_NOEXIST otherwise).
142 * On success, this returns TDB_SUCCESS.
145 * tdb_fetch, tdb_transaction_start, tdb_append, tdb_delete.
147 enum TDB_ERROR tdb_store(struct tdb_context *tdb,
149 struct tdb_data dbuf,
152 /* flags to tdb_store() */
153 #define TDB_REPLACE 1 /* A readability place holder */
154 #define TDB_INSERT 2 /* Don't overwrite an existing entry */
155 #define TDB_MODIFY 3 /* Don't create an existing entry */
158 * tdb_fetch - fetch a value from a tdb.
159 * @tdb: the tdb context returned from tdb_open()
161 * @data: pointer to data.
163 * This looks up a key in the database and sets it in @data.
165 * If it returns TDB_SUCCESS, the key was found: it is your
166 * responsibility to call free() on @data->dptr.
168 * Otherwise, it returns an error (usually, TDB_ERR_NOEXIST) and @data is
171 enum TDB_ERROR tdb_fetch(struct tdb_context *tdb, struct tdb_data key,
172 struct tdb_data *data);
175 * tdb_errorstr - map the tdb error onto a constant readable string
176 * @ecode: the enum TDB_ERROR to map.
178 * This is useful for displaying errors to users.
180 const char *tdb_errorstr(enum TDB_ERROR ecode);
183 * tdb_append - append a value to a key/value pair in a tdb.
184 * @tdb: the tdb context returned from tdb_open()
186 * @dbuf: the data to append.
188 * This is equivalent to fetching a record, reallocating .dptr to add the
189 * data, and writing it back, only it's much more efficient. If the key
190 * doesn't exist, it's equivalent to tdb_store (with an additional hint that
191 * you expect to expand the record in future).
194 * tdb_fetch(), tdb_store()
196 enum TDB_ERROR tdb_append(struct tdb_context *tdb,
197 struct tdb_data key, struct tdb_data dbuf);
200 * tdb_delete - delete a key from a tdb.
201 * @tdb: the tdb context returned from tdb_open()
202 * @key: the key to delete.
204 * Returns TDB_SUCCESS on success, or an error (usually TDB_ERR_NOEXIST).
207 * tdb_fetch(), tdb_store()
209 enum TDB_ERROR tdb_delete(struct tdb_context *tdb, struct tdb_data key);
212 * tdb_exists - does a key exist in the database?
213 * @tdb: the tdb context returned from tdb_open()
214 * @key: the key to search for.
216 * Returns true if it exists, or false if it doesn't or any other error.
218 bool tdb_exists(struct tdb_context *tdb, TDB_DATA key);
221 * tdb_deq - are struct tdb_data equal?
222 * @a: one struct tdb_data
223 * @b: another struct tdb_data
225 static inline bool tdb_deq(struct tdb_data a, struct tdb_data b)
227 return a.dsize == b.dsize && memcmp(a.dptr, b.dptr, a.dsize) == 0;
231 * tdb_mkdata - make a struct tdb_data from const data
232 * @p: the constant pointer
235 * As the dptr member of struct tdb_data is not constant, you need to
236 * cast it. This function keeps thost casts in one place, as well as
237 * suppressing the warning some compilers give when casting away a
238 * qualifier (eg. gcc with -Wcast-qual)
240 static inline struct tdb_data tdb_mkdata(const void *p, size_t len)
243 d.dptr = cast_const(void *, p);
249 * tdb_transaction_start - start a transaction
250 * @tdb: the tdb context returned from tdb_open()
252 * This begins a series of atomic operations. Other processes will be able
253 * to read the tdb, but not alter it (they will block), nor will they see
254 * any changes until tdb_transaction_commit() is called.
256 * Note that if the TDB_ALLOW_NESTING flag is set, a tdb_transaction_start()
257 * within a transaction will succeed, but it's not a real transaction:
258 * (1) An inner transaction which is committed is not actually committed until
259 * the outer transaction is; if the outer transaction is cancelled, the
260 * inner ones are discarded.
261 * (2) tdb_transaction_cancel() marks the outer transaction as having an error,
262 * so the final tdb_transaction_commit() will fail.
263 * (3) the outer transaction will see the results of the inner transaction.
266 * tdb_transaction_cancel, tdb_transaction_commit.
268 enum TDB_ERROR tdb_transaction_start(struct tdb_context *tdb);
271 * tdb_transaction_cancel - abandon a transaction
272 * @tdb: the tdb context returned from tdb_open()
274 * This aborts a transaction, discarding any changes which were made.
275 * tdb_close() does this implicitly.
277 void tdb_transaction_cancel(struct tdb_context *tdb);
280 * tdb_transaction_commit - commit a transaction
281 * @tdb: the tdb context returned from tdb_open()
283 * This completes a transaction, writing any changes which were made.
285 * fsync() is used to commit the transaction (unless TDB_NOSYNC is set),
286 * making it robust against machine crashes, but very slow compared to
287 * other TDB operations.
289 * A failure can only be caused by unexpected errors (eg. I/O or
290 * memory); this is no point looping on transaction failure.
293 * tdb_transaction_prepare_commit()
295 enum TDB_ERROR tdb_transaction_commit(struct tdb_context *tdb);
298 * tdb_transaction_prepare_commit - prepare to commit a transaction
299 * @tdb: the tdb context returned from tdb_open()
301 * This ensures we have the resources to commit a transaction (using
302 * tdb_transaction_commit): if this succeeds then a transaction will only
303 * fail if the write() or fsync() calls fail.
305 * If this fails you must still call tdb_transaction_cancel() to cancel
309 * tdb_transaction_commit()
311 enum TDB_ERROR tdb_transaction_prepare_commit(struct tdb_context *tdb);
314 * tdb_traverse - traverse a TDB
315 * @tdb: the tdb context returned from tdb_open()
316 * @fn: the function to call for every key/value pair (or NULL)
317 * @p: the pointer to hand to @f
319 * This walks the TDB until all they keys have been traversed, or @fn
320 * returns non-zero. If the traverse function or other processes are
321 * changing data or adding or deleting keys, the traverse may be
322 * unreliable: keys may be skipped or (rarely) visited twice.
324 * There is one specific exception: the special case of deleting the
325 * current key does not undermine the reliability of the traversal.
327 * On success, returns the number of keys iterated. On error returns
328 * a negative enum TDB_ERROR value.
330 #define tdb_traverse(tdb, fn, p) \
331 tdb_traverse_(tdb, typesafe_cb_preargs(int, void *, (fn), (p), \
332 struct tdb_context *, \
333 TDB_DATA, TDB_DATA), (p))
335 int64_t tdb_traverse_(struct tdb_context *tdb,
336 int (*fn)(struct tdb_context *,
337 TDB_DATA, TDB_DATA, void *), void *p);
340 * tdb_parse_record - operate directly on data in the database.
341 * @tdb: the tdb context returned from tdb_open()
342 * @key: the key whose record we should hand to @parse
343 * @parse: the function to call for the data
344 * @data: the private pointer to hand to @parse (types must match).
346 * This avoids a copy for many cases, by handing you a pointer into
347 * the memory-mapped database. It also locks the record to prevent
348 * other accesses at the same time.
350 * Do not alter the data handed to parse()!
352 #define tdb_parse_record(tdb, key, parse, data) \
353 tdb_parse_record_((tdb), (key), \
354 typesafe_cb_preargs(enum TDB_ERROR, void *, \
356 TDB_DATA, TDB_DATA), (data))
358 enum TDB_ERROR tdb_parse_record_(struct tdb_context *tdb,
360 enum TDB_ERROR (*parse)(TDB_DATA k,
366 * tdb_get_seqnum - get a database sequence number
367 * @tdb: the tdb context returned from tdb_open()
369 * This returns a sequence number: any change to the database from a
370 * tdb context opened with the TDB_SEQNUM flag will cause that number
371 * to increment. Note that the incrementing is unreliable (it is done
372 * without locking), so this is only useful as an optimization.
374 * For example, you may have a regular database backup routine which
375 * does not operate if the sequence number is unchanged. In the
376 * unlikely event of a failed increment, it will be backed up next
379 * Returns an enum TDB_ERROR (ie. negative) on error.
381 int64_t tdb_get_seqnum(struct tdb_context *tdb);
384 * tdb_firstkey - get the "first" key in a TDB
385 * @tdb: the tdb context returned from tdb_open()
386 * @key: pointer to key.
388 * This returns an arbitrary key in the database; with tdb_nextkey() it allows
389 * open-coded traversal of the database, though it is slightly less efficient
392 * It is your responsibility to free @key->dptr on success.
394 * Returns TDB_ERR_NOEXIST if the database is empty.
396 enum TDB_ERROR tdb_firstkey(struct tdb_context *tdb, struct tdb_data *key);
399 * tdb_nextkey - get the "next" key in a TDB
400 * @tdb: the tdb context returned from tdb_open()
401 * @key: a key returned by tdb_firstkey() or tdb_nextkey().
403 * This returns another key in the database; it will free @key.dptr for
406 * Returns TDB_ERR_NOEXIST if there are no more keys.
408 enum TDB_ERROR tdb_nextkey(struct tdb_context *tdb, struct tdb_data *key);
411 * tdb_chainlock - lock a record in the TDB
412 * @tdb: the tdb context returned from tdb_open()
413 * @key: the key to lock.
415 * This prevents any access occurring to a group of keys including @key,
416 * even if @key does not exist. This allows primitive atomic updates of
417 * records without using transactions.
419 * You cannot begin a transaction while holding a tdb_chainlock(), nor can
420 * you do any operations on any other keys in the database. This also means
421 * that you cannot hold more than one tdb_chainlock() at a time.
426 enum TDB_ERROR tdb_chainlock(struct tdb_context *tdb, TDB_DATA key);
429 * tdb_chainunlock - unlock a record in the TDB
430 * @tdb: the tdb context returned from tdb_open()
431 * @key: the key to unlock.
433 * The key must have previously been locked by tdb_chainlock().
435 void tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key);
438 * tdb_chainlock_read - lock a record in the TDB, for reading
439 * @tdb: the tdb context returned from tdb_open()
440 * @key: the key to lock.
442 * This prevents any changes from occurring to a group of keys including @key,
443 * even if @key does not exist. This allows primitive atomic updates of
444 * records without using transactions.
446 * You cannot begin a transaction while holding a tdb_chainlock_read(), nor can
447 * you do any operations on any other keys in the database. This also means
448 * that you cannot hold more than one tdb_chainlock()/read() at a time.
453 enum TDB_ERROR tdb_chainlock_read(struct tdb_context *tdb, TDB_DATA key);
456 * tdb_chainunlock_read - unlock a record in the TDB for reading
457 * @tdb: the tdb context returned from tdb_open()
458 * @key: the key to unlock.
460 * The key must have previously been locked by tdb_chainlock_read().
462 void tdb_chainunlock_read(struct tdb_context *tdb, TDB_DATA key);
465 * tdb_lockall - lock the entire TDB
466 * @tdb: the tdb context returned from tdb_open()
468 * You cannot hold a tdb_chainlock while calling this. It nests, so you
469 * must call tdb_unlockall as many times as you call tdb_lockall.
471 enum TDB_ERROR tdb_lockall(struct tdb_context *tdb);
474 * tdb_unlockall - unlock the entire TDB
475 * @tdb: the tdb context returned from tdb_open()
477 void tdb_unlockall(struct tdb_context *tdb);
480 * tdb_lockall_read - lock the entire TDB for reading
481 * @tdb: the tdb context returned from tdb_open()
483 * This prevents others writing to the database, eg. tdb_delete, tdb_store,
484 * tdb_append, but not tdb_fetch.
486 * You cannot hold a tdb_chainlock while calling this. It nests, so you
487 * must call tdb_unlockall_read as many times as you call tdb_lockall_read.
489 enum TDB_ERROR tdb_lockall_read(struct tdb_context *tdb);
492 * tdb_unlockall_read - unlock the entire TDB for reading
493 * @tdb: the tdb context returned from tdb_open()
495 void tdb_unlockall_read(struct tdb_context *tdb);
498 * tdb_wipe_all - wipe the database clean
499 * @tdb: the tdb context returned from tdb_open()
501 * Completely erase the database. This is faster than iterating through
502 * each key and doing tdb_delete.
504 enum TDB_ERROR tdb_wipe_all(struct tdb_context *tdb);
507 * tdb_check - check a TDB for consistency
508 * @tdb: the tdb context returned from tdb_open()
509 * @check: function to check each key/data pair (or NULL)
510 * @data: argument for @check, must match type.
512 * This performs a consistency check of the open database, optionally calling
513 * a check() function on each record so you can do your own data consistency
514 * checks as well. If check() returns an error, that is returned from
517 * Returns TDB_SUCCESS or an error.
519 #define tdb_check(tdb, check, data) \
520 tdb_check_((tdb), typesafe_cb_preargs(enum TDB_ERROR, void *, \
526 enum TDB_ERROR tdb_check_(struct tdb_context *tdb,
527 enum TDB_ERROR (*check)(struct tdb_data k,
533 * tdb_error - get the last error (not threadsafe)
534 * @tdb: the tdb context returned from tdb_open()
536 * Returns the last error returned by a TDB function.
538 * This makes porting from TDB1 easier, but note that the last error is not
539 * reliable in threaded programs.
541 enum TDB_ERROR tdb_error(struct tdb_context *tdb);
544 * enum tdb_summary_flags - flags for tdb_summary.
546 enum tdb_summary_flags {
547 TDB_SUMMARY_HISTOGRAMS = 1 /* Draw graphs in the summary. */
551 * tdb_summary - return a string describing the TDB state
552 * @tdb: the tdb context returned from tdb_open()
553 * @flags: flags to control the summary output.
554 * @summary: pointer to string to allocate.
556 * This returns a developer-readable string describing the overall
557 * state of the tdb, such as the percentage used and sizes of records.
558 * It is designed to provide information about the tdb at a glance
559 * without displaying any keys or data in the database.
561 * On success, sets @summary to point to a malloc()'ed nul-terminated
562 * multi-line string. It is your responsibility to free() it.
564 enum TDB_ERROR tdb_summary(struct tdb_context *tdb,
565 enum tdb_summary_flags flags,
570 * tdb_get_flags - return the flags for a tdb
571 * @tdb: the tdb context returned from tdb_open()
573 * This returns the flags on the current tdb. Some of these are caused by
574 * the flags argument to tdb_open(), others (such as TDB_CONVERT) are
577 unsigned int tdb_get_flags(struct tdb_context *tdb);
580 * tdb_add_flag - set a flag for a tdb
581 * @tdb: the tdb context returned from tdb_open()
582 * @flag: one of TDB_NOLOCK, TDB_NOMMAP, TDB_NOSYNC or TDB_ALLOW_NESTING.
584 * You can use this to set a flag on the TDB. You cannot set these flags
585 * on a TDB_INTERNAL tdb.
587 void tdb_add_flag(struct tdb_context *tdb, unsigned flag);
590 * tdb_remove_flag - unset a flag for a tdb
591 * @tdb: the tdb context returned from tdb_open()
592 * @flag: one of TDB_NOLOCK, TDB_NOMMAP, TDB_NOSYNC or TDB_ALLOW_NESTING.
594 * You can use this to clear a flag on the TDB. You cannot clear flags
595 * on a TDB_INTERNAL tdb.
597 void tdb_remove_flag(struct tdb_context *tdb, unsigned flag);
600 * enum tdb_attribute_type - descriminator for union tdb_attribute.
602 enum tdb_attribute_type {
603 TDB_ATTRIBUTE_LOG = 0,
604 TDB_ATTRIBUTE_HASH = 1,
605 TDB_ATTRIBUTE_SEED = 2,
606 TDB_ATTRIBUTE_STATS = 3,
607 TDB_ATTRIBUTE_OPENHOOK = 4,
608 TDB_ATTRIBUTE_FLOCK = 5
612 * tdb_get_attribute - get an attribute for an existing tdb
613 * @tdb: the tdb context returned from tdb_open()
614 * @attr: the union tdb_attribute to set.
616 * This gets an attribute from a TDB which has previously been set (or
617 * may return the default values). Set @attr.base.attr to the
618 * attribute type you want get.
620 * Currently this does not work for TDB_ATTRIBUTE_OPENHOOK.
622 enum TDB_ERROR tdb_get_attribute(struct tdb_context *tdb,
623 union tdb_attribute *attr);
626 * tdb_set_attribute - set an attribute for an existing tdb
627 * @tdb: the tdb context returned from tdb_open()
628 * @attr: the union tdb_attribute to set.
630 * This sets an attribute on a TDB, overriding any previous attribute
631 * of the same type. It returns TDB_ERR_EINVAL if the attribute is
632 * unknown or invalid.
634 * Note that TDB_ATTRIBUTE_HASH, TDB_ATTRIBUTE_SEED and
635 * TDB_ATTRIBUTE_OPENHOOK cannot currently be set after tdb_open.
637 enum TDB_ERROR tdb_set_attribute(struct tdb_context *tdb,
638 const union tdb_attribute *attr);
641 * tdb_unset_attribute - reset an attribute for an existing tdb
642 * @tdb: the tdb context returned from tdb_open()
643 * @type: the attribute type to unset.
645 * This unsets an attribute on a TDB, returning it to the defaults
646 * (where applicable).
648 * Note that it only makes sense for TDB_ATTRIBUTE_LOG and TDB_ATTRIBUTE_FLOCK
651 void tdb_unset_attribute(struct tdb_context *tdb,
652 enum tdb_attribute_type type);
655 * tdb_name - get the name of a tdb
656 * @tdb: the tdb context returned from tdb_open()
658 * This returns a copy of the name string, made at tdb_open() time. If that
659 * argument was NULL (possible for a TDB_INTERNAL db) this will return NULL.
661 * This is mostly useful for logging.
663 const char *tdb_name(const struct tdb_context *tdb);
666 * tdb_fd - get the file descriptor of a tdb
667 * @tdb: the tdb context returned from tdb_open()
669 * This returns the file descriptor for the underlying database file, or -1
672 int tdb_fd(const struct tdb_context *tdb);
675 * struct tdb_attribute_base - common fields for all tdb attributes.
677 struct tdb_attribute_base {
678 enum tdb_attribute_type attr;
679 union tdb_attribute *next;
683 * enum tdb_log_level - log levels for tdb_attribute_log
684 * @TDB_LOG_ERROR: used to log unrecoverable errors such as I/O errors
685 * or internal consistency failures.
686 * @TDB_LOG_USE_ERROR: used to log usage errors such as invalid parameters
687 * or writing to a read-only database.
688 * @TDB_LOG_WARNING: used for informational messages on issues which
689 * are unusual but handled by TDB internally, such
690 * as a failure to mmap or failure to open /dev/urandom.
699 * struct tdb_attribute_log - log function attribute
701 * This attribute provides a hook for you to log errors.
703 struct tdb_attribute_log {
704 struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_LOG */
705 void (*fn)(struct tdb_context *tdb,
706 enum tdb_log_level level,
707 enum TDB_ERROR ecode,
714 * struct tdb_attribute_hash - hash function attribute
716 * This attribute allows you to provide an alternative hash function.
717 * This hash function will be handed keys from the database; it will also
718 * be handed the 8-byte TDB_HASH_MAGIC value for checking the header (the
719 * tdb_open() will fail if the hash value doesn't match the header).
721 * Note that if your hash function gives different results on
722 * different machine endians, your tdb will no longer work across
723 * different architectures!
725 struct tdb_attribute_hash {
726 struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_HASH */
727 uint64_t (*fn)(const void *key, size_t len, uint64_t seed,
733 * struct tdb_attribute_seed - hash function seed attribute
735 * The hash function seed is normally taken from /dev/urandom (or equivalent)
736 * but can be set manually here. This is mainly for testing purposes.
738 struct tdb_attribute_seed {
739 struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_SEED */
744 * struct tdb_attribute_stats - tdb operational statistics
746 * This attribute records statistics of various low-level TDB operations.
747 * This can be used to assist performance evaluation. This is only
748 * useful for tdb_get_attribute().
750 * New fields will be added at the end, hence the "size" argument which
751 * indicates how large your structure is: it must be filled in before
752 * calling tdb_get_attribute(), which will overwrite it with the size
755 struct tdb_attribute_stats {
756 struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_STATS */
757 size_t size; /* = sizeof(struct tdb_attribute_stats) */
759 uint64_t alloc_subhash;
760 uint64_t alloc_chain;
761 uint64_t alloc_bucket_exact;
762 uint64_t alloc_bucket_max;
763 uint64_t alloc_leftover;
764 uint64_t alloc_coalesce_tried;
765 uint64_t alloc_coalesce_iterate_clash;
766 uint64_t alloc_coalesce_lockfail;
767 uint64_t alloc_coalesce_race;
768 uint64_t alloc_coalesce_succeeded;
769 uint64_t alloc_coalesce_num_merged;
771 uint64_t compare_wrong_bucket;
772 uint64_t compare_wrong_offsetbits;
773 uint64_t compare_wrong_keylen;
774 uint64_t compare_wrong_rechash;
775 uint64_t compare_wrong_keycmp;
776 uint64_t transactions;
777 uint64_t transaction_cancel;
778 uint64_t transaction_nest;
779 uint64_t transaction_expand_file;
780 uint64_t transaction_read_direct;
781 uint64_t transaction_read_direct_fail;
782 uint64_t transaction_write_direct;
783 uint64_t transaction_write_direct_fail;
787 uint64_t lock_lowlevel;
788 uint64_t lock_nonblock;
789 uint64_t lock_nonblock_fail;
793 * struct tdb_attribute_openhook - tdb special effects hook for open
795 * This attribute contains a function to call once we have the OPEN_LOCK
796 * for the tdb, but before we've examined its contents. If this succeeds,
797 * the tdb will be populated if it's then zero-length.
799 * This is a hack to allow support for TDB1-style TDB_CLEAR_IF_FIRST
802 struct tdb_attribute_openhook {
803 struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_OPENHOOK */
804 enum TDB_ERROR (*fn)(int fd, void *data);
809 * struct tdb_attribute_flock - tdb special effects hook for file locking
811 * This attribute contains function to call to place locks on a file; it can
812 * be used to support non-blocking operations or lock proxying.
814 * They should return 0 on success, -1 on failure and set errno.
816 * An error will be logged on error if errno is neither EAGAIN nor EINTR
817 * (normally it would only return EAGAIN if waitflag is false, and
818 * loop internally on EINTR).
820 struct tdb_attribute_flock {
821 struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_FLOCK */
822 int (*lock)(int fd,int rw, off_t off, off_t len, bool waitflag, void *);
823 int (*unlock)(int fd, int rw, off_t off, off_t len, void *);
828 * union tdb_attribute - tdb attributes.
830 * This represents all the known attributes.
833 * struct tdb_attribute_log, struct tdb_attribute_hash,
834 * struct tdb_attribute_seed, struct tdb_attribute_stats,
835 * struct tdb_attribute_openhook, struct tdb_attribute_flock.
837 union tdb_attribute {
838 struct tdb_attribute_base base;
839 struct tdb_attribute_log log;
840 struct tdb_attribute_hash hash;
841 struct tdb_attribute_seed seed;
842 struct tdb_attribute_stats stats;
843 struct tdb_attribute_openhook openhook;
844 struct tdb_attribute_flock flock;