#define TDB_CONVERT 16 /* convert endian */
#define TDB_NOSYNC 64 /* don't use synchronous transactions */
#define TDB_SEQNUM 128 /* maintain a sequence number */
+#define TDB_ALLOW_NESTING 256 /* fake nested transactions */
/**
* tdb_close - close and free a tdb.
* to read the tdb, but not alter it (they will block), nor will they see
* any changes until tdb_transaction_commit() is called.
*
+ * Note that if the TDB_ALLOW_NESTING flag is set, a tdb_transaction_start()
+ * within a transaction will succeed, but it's not a real transaction:
+ * (1) An inner transaction which is committed is not actually committed until
+ * the outer transaction is; if the outer transaction is cancelled, the
+ * inner ones are discarded.
+ * (2) tdb_transaction_cancel() marks the outer transaction as having an error,
+ * so the final tdb_transaction_commit() will fail.
+ * (3) the outer transaction will see the results of the inner transaction.
+ *
* See Also:
* tdb_transaction_cancel, tdb_transaction_commit.
*/
* tdb_transaction_commit): if this succeeds then a transaction will only
* fail if the write() or fsync() calls fail.
*
+ * If this fails you must still call tdb_transaction_cancel() to cancel
+ * the transaction.
+ *
* See Also:
* tdb_transaction_commit()
*/
* a negative enum TDB_ERROR value.
*/
#define tdb_traverse(tdb, fn, p) \
- tdb_traverse_(tdb, typesafe_cb_preargs(int, (fn), (p), \
+ tdb_traverse_(tdb, typesafe_cb_preargs(int, void *, (fn), (p), \
struct tdb_context *, \
TDB_DATA, TDB_DATA), (p))
* @tdb: the tdb context returned from tdb_open()
* @key: the key whose record we should hand to @parse
* @parse: the function to call for the data
- * @p: the private pointer to hand to @parse (types must match).
+ * @data: the private pointer to hand to @parse (types must match).
*
* This avoids a copy for many cases, by handing you a pointer into
* the memory-mapped database. It also locks the record to prevent
*
* Do not alter the data handed to parse()!
*/
-#define tdb_parse_record(tdb, key, parse, p) \
+#define tdb_parse_record(tdb, key, parse, data) \
tdb_parse_record_((tdb), (key), \
- typesafe_cb_preargs(enum TDB_ERROR, (parse), (p), \
- TDB_DATA, TDB_DATA), (p))
+ typesafe_cb_preargs(enum TDB_ERROR, void *, \
+ (parse), (data), \
+ TDB_DATA, TDB_DATA), (data))
enum TDB_ERROR tdb_parse_record_(struct tdb_context *tdb,
TDB_DATA key,
- enum TDB_ERROR (*parse)(TDB_DATA key,
- TDB_DATA data,
- void *p),
- void *p);
+ enum TDB_ERROR (*parse)(TDB_DATA k,
+ TDB_DATA d,
+ void *data),
+ void *data);
/**
* tdb_get_seqnum - get a database sequence number
* @tdb: the tdb context returned from tdb_open()
* @key: the key to lock.
*
- * This prevents any changes from occurring to a group of keys including @key,
+ * This prevents any access occurring to a group of keys including @key,
* even if @key does not exist. This allows primitive atomic updates of
* records without using transactions.
*
*/
void tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key);
+/**
+ * tdb_chainlock_read - lock a record in the TDB, for reading
+ * @tdb: the tdb context returned from tdb_open()
+ * @key: the key to lock.
+ *
+ * This prevents any changes from occurring to a group of keys including @key,
+ * even if @key does not exist. This allows primitive atomic updates of
+ * records without using transactions.
+ *
+ * You cannot begin a transaction while holding a tdb_chainlock_read(), nor can
+ * you do any operations on any other keys in the database. This also means
+ * that you cannot hold more than one tdb_chainlock()/read() at a time.
+ *
+ * See Also:
+ * tdb_chainlock()
+ */
+enum TDB_ERROR tdb_chainlock_read(struct tdb_context *tdb, TDB_DATA key);
+
+/**
+ * tdb_chainunlock_read - unlock a record in the TDB for reading
+ * @tdb: the tdb context returned from tdb_open()
+ * @key: the key to unlock.
+ *
+ * The key must have previously been locked by tdb_chainlock_read().
+ */
+void tdb_chainunlock_read(struct tdb_context *tdb, TDB_DATA key);
+
/**
* tdb_lockall - lock the entire TDB
* @tdb: the tdb context returned from tdb_open()
* tdb_check - check a TDB for consistency
* @tdb: the tdb context returned from tdb_open()
* @check: function to check each key/data pair (or NULL)
- * @private: argument for @check, must match type.
+ * @data: argument for @check, must match type.
*
* This performs a consistency check of the open database, optionally calling
* a check() function on each record so you can do your own data consistency
*
* Returns TDB_SUCCESS or an error.
*/
-#define tdb_check(tdb, check, private) \
- tdb_check_((tdb), typesafe_cb_preargs(enum TDB_ERROR, \
- (check), (private), \
+#define tdb_check(tdb, check, data) \
+ tdb_check_((tdb), typesafe_cb_preargs(enum TDB_ERROR, void *, \
+ (check), (data), \
struct tdb_data, \
struct tdb_data), \
- (private))
+ (data))
enum TDB_ERROR tdb_check_(struct tdb_context *tdb,
- enum TDB_ERROR (*check)(struct tdb_data key,
- struct tdb_data data,
- void *private),
- void *private);
+ enum TDB_ERROR (*check)(struct tdb_data k,
+ struct tdb_data d,
+ void *data),
+ void *data);
/**
* tdb_error - get the last error (not threadsafe)
/**
* tdb_add_flag - set a flag for a tdb
* @tdb: the tdb context returned from tdb_open()
- * @flag: one of TDB_NOLOCK, TDB_NOMMAP or TDB_NOSYNC.
+ * @flag: one of TDB_NOLOCK, TDB_NOMMAP, TDB_NOSYNC or TDB_ALLOW_NESTING.
*
* You can use this to set a flag on the TDB. You cannot set these flags
* on a TDB_INTERNAL tdb.
/**
* tdb_remove_flag - unset a flag for a tdb
* @tdb: the tdb context returned from tdb_open()
- * @flag: one of TDB_NOLOCK, TDB_NOMMAP or TDB_NOSYNC.
+ * @flag: one of TDB_NOLOCK, TDB_NOMMAP, TDB_NOSYNC or TDB_ALLOW_NESTING.
*
* You can use this to clear a flag on the TDB. You cannot clear flags
* on a TDB_INTERNAL tdb.
*/
void tdb_remove_flag(struct tdb_context *tdb, unsigned flag);
+/**
+ * enum tdb_attribute_type - descriminator for union tdb_attribute.
+ */
+enum tdb_attribute_type {
+ TDB_ATTRIBUTE_LOG = 0,
+ TDB_ATTRIBUTE_HASH = 1,
+ TDB_ATTRIBUTE_SEED = 2,
+ TDB_ATTRIBUTE_STATS = 3,
+ TDB_ATTRIBUTE_OPENHOOK = 4,
+ TDB_ATTRIBUTE_FLOCK = 5
+};
+
+/**
+ * tdb_get_attribute - get an attribute for an existing tdb
+ * @tdb: the tdb context returned from tdb_open()
+ * @attr: the union tdb_attribute to set.
+ *
+ * This gets an attribute from a TDB which has previously been set (or
+ * may return the default values). Set @attr.base.attr to the
+ * attribute type you want get.
+ *
+ * Currently this does not work for TDB_ATTRIBUTE_OPENHOOK.
+ */
+enum TDB_ERROR tdb_get_attribute(struct tdb_context *tdb,
+ union tdb_attribute *attr);
+
+/**
+ * tdb_set_attribute - set an attribute for an existing tdb
+ * @tdb: the tdb context returned from tdb_open()
+ * @attr: the union tdb_attribute to set.
+ *
+ * This sets an attribute on a TDB, overriding any previous attribute
+ * of the same type. It returns TDB_ERR_EINVAL if the attribute is
+ * unknown or invalid.
+ *
+ * Note that TDB_ATTRIBUTE_HASH, TDB_ATTRIBUTE_SEED and
+ * TDB_ATTRIBUTE_OPENHOOK cannot currently be set after tdb_open.
+ */
+enum TDB_ERROR tdb_set_attribute(struct tdb_context *tdb,
+ const union tdb_attribute *attr);
+
+/**
+ * tdb_unset_attribute - reset an attribute for an existing tdb
+ * @tdb: the tdb context returned from tdb_open()
+ * @type: the attribute type to unset.
+ *
+ * This unsets an attribute on a TDB, returning it to the defaults
+ * (where applicable).
+ *
+ * Note that it only makes sense for TDB_ATTRIBUTE_LOG and TDB_ATTRIBUTE_FLOCK
+ * to be unset.
+ */
+void tdb_unset_attribute(struct tdb_context *tdb,
+ enum tdb_attribute_type type);
+
/**
* tdb_name - get the name of a tdb
* @tdb: the tdb context returned from tdb_open()
*/
int tdb_fd(const struct tdb_context *tdb);
-/**
- * enum tdb_attribute_type - descriminator for union tdb_attribute.
- */
-enum tdb_attribute_type {
- TDB_ATTRIBUTE_LOG = 0,
- TDB_ATTRIBUTE_HASH = 1,
- TDB_ATTRIBUTE_SEED = 2,
- TDB_ATTRIBUTE_STATS = 3
-};
-
/**
* struct tdb_attribute_base - common fields for all tdb attributes.
*/
*/
struct tdb_attribute_log {
struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_LOG */
- void (*log_fn)(struct tdb_context *tdb,
- enum tdb_log_level level,
- void *log_private,
- const char *message);
- void *log_private;
+ void (*fn)(struct tdb_context *tdb,
+ enum tdb_log_level level,
+ const char *message,
+ void *data);
+ void *data;
};
/**
*/
struct tdb_attribute_hash {
struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_HASH */
- uint64_t (*hash_fn)(const void *key, size_t len, uint64_t seed,
- void *priv);
- void *hash_private;
+ uint64_t (*fn)(const void *key, size_t len, uint64_t seed,
+ void *data);
+ void *data;
};
/**
* struct tdb_attribute_stats - tdb operational statistics
*
* This attribute records statistics of various low-level TDB operations.
- * This can be used to assist performance evaluation.
+ * This can be used to assist performance evaluation. This is only
+ * useful for tdb_get_attribute().
*
* New fields will be added at the end, hence the "size" argument which
- * indicates how large your structure is. If your size is larger than
- * that known about by this version of tdb, the size will be reduced to
- * the known structure size. Thus you can detect older versions, and
- * thus know that newer stats will not be updated.
+ * indicates how large your structure is: it must be filled in before
+ * calling tdb_get_attribute(), which will overwrite it with the size
+ * tdb knows about.
*/
struct tdb_attribute_stats {
struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_STATS */
uint64_t alloc_bucket_max;
uint64_t alloc_leftover;
uint64_t alloc_coalesce_tried;
+ uint64_t alloc_coalesce_iterate_clash;
uint64_t alloc_coalesce_lockfail;
uint64_t alloc_coalesce_race;
uint64_t alloc_coalesce_succeeded;
- uint64_t alloc_coalesce_num_merged;
+ uint64_t alloc_coalesce_num_merged;
uint64_t compares;
uint64_t compare_wrong_bucket;
uint64_t compare_wrong_offsetbits;
uint64_t compare_wrong_keylen;
uint64_t compare_wrong_rechash;
uint64_t compare_wrong_keycmp;
+ uint64_t transactions;
+ uint64_t transaction_cancel;
+ uint64_t transaction_nest;
+ uint64_t transaction_expand_file;
+ uint64_t transaction_read_direct;
+ uint64_t transaction_read_direct_fail;
+ uint64_t transaction_write_direct;
+ uint64_t transaction_write_direct_fail;
uint64_t expands;
uint64_t frees;
uint64_t locks;
- uint64_t lock_lowlevel;
- uint64_t lock_nonblock;
+ uint64_t lock_lowlevel;
+ uint64_t lock_nonblock;
+ uint64_t lock_nonblock_fail;
+};
+
+/**
+ * struct tdb_attribute_openhook - tdb special effects hook for open
+ *
+ * This attribute contains a function to call once we have the OPEN_LOCK
+ * for the tdb, but before we've examined its contents. If this succeeds,
+ * the tdb will be populated if it's then zero-length.
+ *
+ * This is a hack to allow support for TDB1-style TDB_CLEAR_IF_FIRST
+ * behaviour.
+ */
+struct tdb_attribute_openhook {
+ struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_OPENHOOK */
+ enum TDB_ERROR (*fn)(int fd, void *data);
+ void *data;
+};
+
+/**
+ * struct tdb_attribute_flock - tdb special effects hook for file locking
+ *
+ * This attribute contains function to call to place locks on a file; it can
+ * be used to support non-blocking operations or lock proxying.
+ *
+ * They should return 0 on success, -1 on failure and set errno.
+ *
+ * An error will be logged on error if errno is neither EAGAIN nor EINTR
+ * (normally it would only return EAGAIN if waitflag is false, and
+ * loop internally on EINTR).
+ */
+struct tdb_attribute_flock {
+ struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_FLOCK */
+ int (*lock)(int fd,int rw, off_t off, off_t len, bool waitflag, void *);
+ int (*unlock)(int fd, int rw, off_t off, off_t len, void *);
+ void *data;
};
/**
*
* See also:
* struct tdb_attribute_log, struct tdb_attribute_hash,
- * struct tdb_attribute_seed, struct tdb_attribute_stats.
+ * struct tdb_attribute_seed, struct tdb_attribute_stats,
+ * struct tdb_attribute_openhook, struct tdb_attribute_flock.
*/
union tdb_attribute {
struct tdb_attribute_base base;
struct tdb_attribute_hash hash;
struct tdb_attribute_seed seed;
struct tdb_attribute_stats stats;
+ struct tdb_attribute_openhook openhook;
+ struct tdb_attribute_flock flock;
};
#ifdef __cplusplus
projects / ccan / blobdiff