*/
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,
- TDB_ATTRIBUTE_OPENHOOK = 4
-};
-
/**
* struct tdb_attribute_base - common fields for all tdb attributes.
*/
* 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 */
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;
+};
+
/**
* union tdb_attribute - tdb attributes.
*
* See also:
* struct tdb_attribute_log, struct tdb_attribute_hash,
* struct tdb_attribute_seed, struct tdb_attribute_stats,
- * struct tdb_attribute_openhook.
+ * struct tdb_attribute_openhook, struct tdb_attribute_flock.
*/
union tdb_attribute {
struct tdb_attribute_base base;
struct tdb_attribute_seed seed;
struct tdb_attribute_stats stats;
struct tdb_attribute_openhook openhook;
+ struct tdb_attribute_flock flock;
};
#ifdef __cplusplus