#include <signal.h>
/* For uint64_t */
#include <stdint.h>
+/* For bool */
+#include <stdbool.h>
+/* For memcmp */
+#include <string.h>
#endif
#include <ccan/compiler/compiler.h>
#include <ccan/typesafe_cb/typesafe_cb.h>
+#include <ccan/cast/cast.h>
union tdb_attribute;
struct tdb_context;
#define TDB_NOMMAP 8 /* don't use mmap */
#define TDB_CONVERT 16 /* convert endian */
#define TDB_NOSYNC 64 /* don't use synchronous transactions */
+#define TDB_SEQNUM 128 /* maintain a sequence number */
/**
* tdb_close - close and free a tdb.
*/
enum TDB_ERROR tdb_delete(struct tdb_context *tdb, struct tdb_data key);
+/**
+ * tdb_exists - does a key exist in the database?
+ * @tdb: the tdb context returned from tdb_open()
+ * @key: the key to search for.
+ *
+ * Returns true if it exists, or false if it doesn't or any other error.
+ */
+bool tdb_exists(struct tdb_context *tdb, TDB_DATA key);
+
+/**
+ * tdb_deq - are struct tdb_data equal?
+ * @a: one struct tdb_data
+ * @b: another struct tdb_data
+ */
+static inline bool tdb_deq(struct tdb_data a, struct tdb_data b)
+{
+ return a.dsize == b.dsize && memcmp(a.dptr, b.dptr, a.dsize) == 0;
+}
+
+/**
+ * tdb_mkdata - make a struct tdb_data from const data
+ * @p: the constant pointer
+ * @len: the length
+ *
+ * As the dptr member of struct tdb_data is not constant, you need to
+ * cast it. This function keeps thost casts in one place, as well as
+ * suppressing the warning some compilers give when casting away a
+ * qualifier (eg. gcc with -Wcast-qual)
+ */
+static inline struct tdb_data tdb_mkdata(const void *p, size_t len)
+{
+ struct tdb_data d;
+ d.dptr = cast_const(void *, p);
+ d.dsize = len;
+ return d;
+}
+
/**
* tdb_transaction_start - start a transaction
* @tdb: the tdb context returned from tdb_open()
* 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))
int (*fn)(struct tdb_context *,
TDB_DATA, TDB_DATA, void *), void *p);
+/**
+ * tdb_parse_record - operate directly on data in the database.
+ * @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
+ * @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
+ * other accesses at the same time.
+ *
+ * Do not alter the data handed to parse()!
+ */
+#define tdb_parse_record(tdb, key, parse, data) \
+ tdb_parse_record_((tdb), (key), \
+ 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 k,
+ TDB_DATA d,
+ void *data),
+ void *data);
+
+/**
+ * tdb_get_seqnum - get a database sequence number
+ * @tdb: the tdb context returned from tdb_open()
+ *
+ * This returns a sequence number: any change to the database from a
+ * tdb context opened with the TDB_SEQNUM flag will cause that number
+ * to increment. Note that the incrementing is unreliable (it is done
+ * without locking), so this is only useful as an optimization.
+ *
+ * For example, you may have a regular database backup routine which
+ * does not operate if the sequence number is unchanged. In the
+ * unlikely event of a failed increment, it will be backed up next
+ * time any way.
+ *
+ * Returns an enum TDB_ERROR (ie. negative) on error.
+ */
+int64_t tdb_get_seqnum(struct tdb_context *tdb);
+
/**
* tdb_firstkey - get the "first" key in a TDB
* @tdb: the tdb context returned from tdb_open()
* @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.
*
* tdb_chainunlock - unlock a record in the TDB
* @tdb: the tdb context returned from tdb_open()
* @key: the key to unlock.
+ *
+ * The key must have previously been locked by tdb_chainlock().
*/
-enum TDB_ERROR tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key);
+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()
+ *
+ * You cannot hold a tdb_chainlock while calling this. It nests, so you
+ * must call tdb_unlockall as many times as you call tdb_lockall.
+ */
+enum TDB_ERROR tdb_lockall(struct tdb_context *tdb);
+
+/**
+ * tdb_unlockall - unlock the entire TDB
+ * @tdb: the tdb context returned from tdb_open()
+ */
+void tdb_unlockall(struct tdb_context *tdb);
+
+/**
+ * tdb_lockall_read - lock the entire TDB for reading
+ * @tdb: the tdb context returned from tdb_open()
+ *
+ * This prevents others writing to the database, eg. tdb_delete, tdb_store,
+ * tdb_append, but not tdb_fetch.
+ *
+ * You cannot hold a tdb_chainlock while calling this. It nests, so you
+ * must call tdb_unlockall_read as many times as you call tdb_lockall_read.
+ */
+enum TDB_ERROR tdb_lockall_read(struct tdb_context *tdb);
+
+/**
+ * tdb_unlockall_read - unlock the entire TDB for reading
+ * @tdb: the tdb context returned from tdb_open()
+ */
+void tdb_unlockall_read(struct tdb_context *tdb);
+
+/**
+ * tdb_wipe_all - wipe the database clean
+ * @tdb: the tdb context returned from tdb_open()
+ *
+ * Completely erase the database. This is faster than iterating through
+ * each key and doing tdb_delete.
+ */
+enum TDB_ERROR tdb_wipe_all(struct tdb_context *tdb);
/**
* 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: the tdb context returned from tdb_open()
+ *
+ * Returns the last error returned by a TDB function.
+ *
+ * This makes porting from TDB1 easier, but note that the last error is not
+ * reliable in threaded programs.
+ */
+enum TDB_ERROR tdb_error(struct tdb_context *tdb);
/**
* enum tdb_summary_flags - flags for tdb_summary.
TDB_ATTRIBUTE_LOG = 0,
TDB_ATTRIBUTE_HASH = 1,
TDB_ATTRIBUTE_SEED = 2,
- TDB_ATTRIBUTE_STATS = 3
+ 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()
+ *
+ * This returns a copy of the name string, made at tdb_open() time. If that
+ * argument was NULL (possible for a TDB_INTERNAL db) this will return NULL.
+ *
+ * This is mostly useful for logging.
+ */
+const char *tdb_name(const struct tdb_context *tdb);
+
+/**
+ * tdb_fd - get the file descriptor of a tdb
+ * @tdb: the tdb context returned from tdb_open()
+ *
+ * This returns the file descriptor for the underlying database file, or -1
+ * for TDB_INTERNAL.
+ */
+int tdb_fd(const struct tdb_context *tdb);
+
/**
* 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;
};
/**
uint64_t lock_nonblock;
};
+/**
+ * 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;
+};
+
/**
* 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_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;
};
-/**
- * tdb_null - a convenient value for errors.
- */
-extern struct tdb_data tdb_null;
-
#ifdef __cplusplus
}
#endif
projects / ccan / blobdiff