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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-05 17:46:09 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-05 17:46:09 +0000
commit48ae1a0fb55b89de931512ffe4afd2c629ae828a (patch)
treea464b4d09295e0d1cdc290e42dc8cc97c4e044fe /include/tdb.h
parentInitial commit. (diff)
downloadtdb-48ae1a0fb55b89de931512ffe4afd2c629ae828a.tar.xz
tdb-48ae1a0fb55b89de931512ffe4afd2c629ae828a.zip
Adding upstream version 1.4.8.upstream/1.4.8upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+#ifndef __TDB_H__
+#define __TDB_H__
+
+/*
+ Unix SMB/CIFS implementation.
+
+ trivial database library
+
+ Copyright (C) Andrew Tridgell 1999-2004
+
+ ** NOTE! The following LGPL license applies to the tdb
+ ** library. This does NOT imply that all of Samba is released
+ ** under the LGPL
+
+ This library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 3 of the License, or (at your option) any later version.
+
+ This library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with this library; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <signal.h>
+#include <stdbool.h>
+
+/* for old gcc releases that don't have the feature test macro __has_attribute */
+#ifndef __has_attribute
+#define __has_attribute(x) 0
+#endif
+
+#ifndef _PUBLIC_
+#if __has_attribute(visibility)
+#define _PUBLIC_ __attribute__((visibility("default")))
+#else
+#define _PUBLIC_
+#endif
+#endif
+
+/**
+ * @defgroup tdb The tdb API
+ *
+ * tdb is a Trivial database. In concept, it is very much like GDBM, and BSD's
+ * DB except that it allows multiple simultaneous writers and uses locking
+ * internally to keep writers from trampling on each other. tdb is also
+ * extremely small.
+ *
+ * @section tdb_interface Interface
+ *
+ * The interface is very similar to gdbm except for the following:
+ *
+ * <ul>
+ * <li>different open interface. The tdb_open call is more similar to a
+ * traditional open()</li>
+ * <li>no tdbm_reorganise() function</li>
+ * <li>no tdbm_sync() function. No operations are cached in the library
+ * anyway</li>
+ * <li>added a tdb_traverse() function for traversing the whole database</li>
+ * <li>added transactions support</li>
+ * </ul>
+ *
+ * A general rule for using tdb is that the caller frees any returned TDB_DATA
+ * structures. Just call free(p.dptr) to free a TDB_DATA return value called p.
+ * This is the same as gdbm.
+ *
+ * @{
+ */
+
+/** Flags to tdb_store() */
+#define TDB_REPLACE 1 /** Unused */
+#define TDB_INSERT 2 /** Don't overwrite an existing entry */
+#define TDB_MODIFY 3 /** Don't create an existing entry */
+
+/** Flags for tdb_open() */
+#define TDB_DEFAULT 0 /** just a readability place holder */
+#define TDB_CLEAR_IF_FIRST 1 /** If this is the first open, wipe the db */
+#define TDB_INTERNAL 2 /** Don't store on disk */
+#define TDB_NOLOCK 4 /** Don't do any locking */
+#define TDB_NOMMAP 8 /** Don't use mmap */
+#define TDB_CONVERT 16 /** Convert endian (internal use) */
+#define TDB_BIGENDIAN 32 /** Header is big-endian (internal use) */
+#define TDB_NOSYNC 64 /** Don't use synchronous transactions */
+#define TDB_SEQNUM 128 /** Maintain a sequence number */
+#define TDB_VOLATILE 256 /** Activate the per-hashchain freelist, default 5 */
+#define TDB_ALLOW_NESTING 512 /** Allow transactions to nest */
+#define TDB_DISALLOW_NESTING 1024 /** Disallow transactions to nest */
+#define TDB_INCOMPATIBLE_HASH 2048 /** Better hashing: can't be opened by tdb < 1.2.6. */
+#define TDB_MUTEX_LOCKING 4096 /** optimized locking using robust mutexes if supported,
+ only with tdb >= 1.3.0 and TDB_CLEAR_IF_FIRST
+ after checking tdb_runtime_check_for_robust_mutexes() */
+
+/** The tdb error codes */
+enum TDB_ERROR {TDB_SUCCESS=0, TDB_ERR_CORRUPT, TDB_ERR_IO, TDB_ERR_LOCK,
+ TDB_ERR_OOM, TDB_ERR_EXISTS, TDB_ERR_NOLOCK, TDB_ERR_LOCK_TIMEOUT,
+ TDB_ERR_NOEXIST, TDB_ERR_EINVAL, TDB_ERR_RDONLY,
+ TDB_ERR_NESTING};
+
+/** Debugging uses one of the following levels */
+enum tdb_debug_level {TDB_DEBUG_FATAL = 0, TDB_DEBUG_ERROR,
+ TDB_DEBUG_WARNING, TDB_DEBUG_TRACE};
+
+/** The tdb data structure */
+typedef struct TDB_DATA {
+ unsigned char *dptr;
+ size_t dsize;
+} TDB_DATA;
+
+#ifndef PRINTF_ATTRIBUTE
+#if __has_attribute(format) || (__GNUC__ >= 3)
+/** Use gcc attribute to check printf fns. a1 is the 1-based index of
+ * the parameter containing the format, and a2 the index of the first
+ * argument. Note that some gcc 2.x versions don't handle this
+ * properly **/
+#define PRINTF_ATTRIBUTE(a1, a2) __attribute__ ((format (__printf__, a1, a2)))
+#else
+#define PRINTF_ATTRIBUTE(a1, a2)
+#endif
+#endif
+
+/** This is the context structure that is returned from a db open. */
+typedef struct tdb_context TDB_CONTEXT;
+
+typedef int (*tdb_traverse_func)(struct tdb_context *, TDB_DATA, TDB_DATA, void *);
+typedef void (*tdb_log_func)(struct tdb_context *, enum tdb_debug_level, const char *, ...) PRINTF_ATTRIBUTE(3, 4);
+typedef unsigned int (*tdb_hash_func)(TDB_DATA *key);
+
+struct tdb_logging_context {
+ tdb_log_func log_fn;
+ void *log_private;
+};
+
+/**
+ * @brief Open the database and creating it if necessary.
+ *
+ * @param[in] name The name of the db to open.
+ *
+ * @param[in] hash_size The hash size is advisory, use zero for a default
+ * value.
+ *
+ * @param[in] tdb_flags The flags to use to open the db:\n\n
+ * TDB_CLEAR_IF_FIRST - Clear database if we are the
+ * only one with it open\n
+ * TDB_INTERNAL - Don't use a file, instead store the
+ * data in memory. The filename is
+ * ignored in this case.\n
+ * TDB_NOLOCK - Don't do any locking\n
+ * TDB_NOMMAP - Don't use mmap\n
+ * TDB_NOSYNC - Don't synchronise transactions to disk\n
+ * TDB_SEQNUM - Maintain a sequence number\n
+ * TDB_VOLATILE - activate the per-hashchain freelist,
+ * default 5.\n
+ * TDB_ALLOW_NESTING - Allow transactions to nest.\n
+ * TDB_DISALLOW_NESTING - Disallow transactions to nest.\n
+ * TDB_INCOMPATIBLE_HASH - Better hashing: can't be opened by tdb < 1.2.6.\n
+ * TDB_MUTEX_LOCKING - Optimized locking using robust mutexes if supported,
+ * can't be opened by tdb < 1.3.0.
+ * Only valid in combination with TDB_CLEAR_IF_FIRST
+ * after checking tdb_runtime_check_for_robust_mutexes()\n
+ *
+ * @param[in] open_flags Flags for the open(2) function.
+ *
+ * @param[in] mode The mode for the open(2) function.
+ *
+ * @return A tdb context structure, NULL on error.
+ */
+_PUBLIC_ struct tdb_context *tdb_open(const char *name, int hash_size, int tdb_flags,
+ int open_flags, mode_t mode);
+
+/**
+ * @brief Open the database and creating it if necessary.
+ *
+ * This is like tdb_open(), but allows you to pass an initial logging and
+ * hash function. Be careful when passing a hash function - all users of the
+ * database must use the same hash function or you will get data corruption.
+ *
+ * @param[in] name The name of the db to open.
+ *
+ * @param[in] hash_size The hash size is advisory, use zero for a default
+ * value.
+ *
+ * @param[in] tdb_flags The flags to use to open the db:\n\n
+ * TDB_CLEAR_IF_FIRST - Clear database if we are the
+ * only one with it open\n
+ * TDB_INTERNAL - Don't use a file, instead store the
+ * data in memory. The filename is
+ * ignored in this case.\n
+ * TDB_NOLOCK - Don't do any locking\n
+ * TDB_NOMMAP - Don't use mmap\n
+ * TDB_NOSYNC - Don't synchronise transactions to disk\n
+ * TDB_SEQNUM - Maintain a sequence number\n
+ * TDB_VOLATILE - activate the per-hashchain freelist,
+ * default 5.\n
+ * TDB_ALLOW_NESTING - Allow transactions to nest.\n
+ * TDB_DISALLOW_NESTING - Disallow transactions to nest.\n
+ * TDB_INCOMPATIBLE_HASH - Better hashing: can't be opened by tdb < 1.2.6.\n
+ * TDB_MUTEX_LOCKING - Optimized locking using robust mutexes if supported,
+ * can't be opened by tdb < 1.3.0.
+ * Only valid in combination with TDB_CLEAR_IF_FIRST
+ * after checking tdb_runtime_check_for_robust_mutexes()\n
+ *
+ * @param[in] open_flags Flags for the open(2) function.
+ *
+ * @param[in] mode The mode for the open(2) function.
+ *
+ * @param[in] log_ctx The logging function to use.
+ *
+ * @param[in] hash_fn The hash function you want to use.
+ *
+ * @return A tdb context structure, NULL on error.
+ *
+ * @see tdb_open()
+ */
+_PUBLIC_ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
+ int open_flags, mode_t mode,
+ const struct tdb_logging_context *log_ctx,
+ tdb_hash_func hash_fn);
+
+/**
+ * @brief Set the maximum number of dead records per hash chain.
+ *
+ * @param[in] tdb The database handle to set the maximum.
+ *
+ * @param[in] max_dead The maximum number of dead records per hash chain.
+ */
+_PUBLIC_ void tdb_set_max_dead(struct tdb_context *tdb, int max_dead);
+
+/**
+ * @brief Reopen a tdb.
+ *
+ * This can be used after a fork to ensure that we have an independent seek
+ * pointer from our parent and to re-establish locks.
+ *
+ * @param[in] tdb The database to reopen. It will be free'd on error!
+ *
+ * @return 0 on success, -1 on error.
+ *
+ * @note Don't call tdb_error() after this function cause the tdb context will
+ * be freed on error.
+ */
+_PUBLIC_ int tdb_reopen(struct tdb_context *tdb);
+
+/**
+ * @brief Reopen all tdb's
+ *
+ * If the parent is longlived (ie. a parent daemon architecture), we know it
+ * will keep it's active lock on a tdb opened with CLEAR_IF_FIRST. Thus for
+ * child processes we don't have to add an active lock. This is essential to
+ * improve performance on systems that keep POSIX locks as a non-scalable data
+ * structure in the kernel.
+ *
+ * @param[in] parent_longlived Whether the parent is longlived or not.
+ *
+ * @return 0 on success, -1 on error.
+ */
+_PUBLIC_ int tdb_reopen_all(int parent_longlived);
+
+/**
+ * @brief Set a different tdb logging function.
+ *
+ * @param[in] tdb The tdb to set the logging function.
+ *
+ * @param[in] log_ctx The logging function to set.
+ */
+_PUBLIC_ void tdb_set_logging_function(struct tdb_context *tdb, const struct tdb_logging_context *log_ctx);
+
+/**
+ * @brief Get the tdb last error code.
+ *
+ * @param[in] tdb The tdb to get the error code from.
+ *
+ * @return A TDB_ERROR code.
+ *
+ * @see TDB_ERROR
+ */
+_PUBLIC_ enum TDB_ERROR tdb_error(struct tdb_context *tdb);
+
+/**
+ * @brief Get a error string for the last tdb error
+ *
+ * @param[in] tdb The tdb to get the error code from.
+ *
+ * @return An error string.
+ */
+_PUBLIC_ const char *tdb_errorstr(struct tdb_context *tdb);
+
+/**
+ * @brief Fetch an entry in the database given a key.
+ *
+ * The caller must free the resulting data.
+ *
+ * @param[in] tdb The tdb to fetch the key.
+ *
+ * @param[in] key The key to fetch.
+ *
+ * @return The key entry found in the database, NULL on error with
+ * TDB_ERROR set.
+ *
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ */
+_PUBLIC_ TDB_DATA tdb_fetch(struct tdb_context *tdb, TDB_DATA key);
+
+/**
+ * @brief Hand a record to a parser function without allocating it.
+ *
+ * This function is meant as a fast tdb_fetch alternative for large records
+ * that are frequently read. The "key" and "data" arguments point directly
+ * into the tdb shared memory, they are not aligned at any boundary.
+ *
+ * @warning The parser is called while tdb holds a lock on the record. DO NOT
+ * call other tdb routines from within the parser. Also, for good performance
+ * you should make the parser fast to allow parallel operations.
+ *
+ * @param[in] tdb The tdb to parse the record.
+ *
+ * @param[in] key The key to parse.
+ *
+ * @param[in] parser The parser to use to parse the data.
+ *
+ * @param[in] private_data A private data pointer which is passed to the parser
+ * function.
+ *
+ * @return -1 if the record was not found. If the record was found,
+ * the return value of "parser" is passed up to the caller.
+ */
+_PUBLIC_ int tdb_parse_record(struct tdb_context *tdb, TDB_DATA key,
+ int (*parser)(TDB_DATA key, TDB_DATA data,
+ void *private_data),
+ void *private_data);
+
+/**
+ * @brief Delete an entry in the database given a key.
+ *
+ * @param[in] tdb The tdb to delete the key.
+ *
+ * @param[in] key The key to delete.
+ *
+ * @return 0 on success, -1 if the key doesn't exist.
+ */
+_PUBLIC_ int tdb_delete(struct tdb_context *tdb, TDB_DATA key);
+
+/**
+ * @brief Store an element in the database.
+ *
+ * This replaces any existing element with the same key.
+ *
+ * @param[in] tdb The tdb to store the entry.
+ *
+ * @param[in] key The key to use to store the entry.
+ *
+ * @param[in] dbuf The data to store under the key.
+ *
+ * @param[in] flag The flags to store the key:\n\n
+ * TDB_INSERT: Don't overwrite an existing entry.\n
+ * TDB_MODIFY: Don't create a new entry\n
+ *
+ * @return 0 on success, -1 on error with error code set.
+ *
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ */
+_PUBLIC_ int tdb_store(struct tdb_context *tdb, TDB_DATA key, TDB_DATA dbuf, int flag);
+
+
+/**
+ * @brief Store an element in the database.
+ *
+ * This replaces any existing element with the same key.
+ *
+ * @param[in] tdb The tdb to store the entry.
+ *
+ * @param[in] key The key to use to store the entry.
+ *
+ * @param[in] dbufs A vector of memory chunks to write
+ *
+ * @param[in] num_dbufs Length of the dbufs vector
+ *
+ * @param[in] flag The flags to store the key:\n\n
+ * TDB_INSERT: Don't overwrite an existing entry.\n
+ * TDB_MODIFY: Don't create a new entry\n
+ *
+ * @return 0 on success, -1 on error with error code set.
+ *
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ */
+_PUBLIC_ int tdb_storev(struct tdb_context *tdb, TDB_DATA key,
+ const TDB_DATA *dbufs, int num_dbufs, int flag);
+
+/**
+ * @brief Append data to an entry.
+ *
+ * If the entry doesn't exist, it will create a new one.
+ *
+ * @param[in] tdb The database to use.
+ *
+ * @param[in] key The key to append the data.
+ *
+ * @param[in] new_dbuf The data to append to the key.
+ *
+ * @return 0 on success, -1 on error with error code set.
+ *
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ */
+_PUBLIC_ int tdb_append(struct tdb_context *tdb, TDB_DATA key, TDB_DATA new_dbuf);
+
+/**
+ * @brief Close a database.
+ *
+ * @param[in] tdb The database to close. The context will be free'd.
+ *
+ * @return 0 for success, -1 on error.
+ *
+ * @note Don't call tdb_error() after this function cause the tdb context will
+ * be freed on error.
+ */
+_PUBLIC_ int tdb_close(struct tdb_context *tdb);
+
+/**
+ * @brief Find the first entry in the database and return its key.
+ *
+ * The caller must free the returned data.
+ *
+ * @param[in] tdb The database to use.
+ *
+ * @return The first entry of the database, an empty TDB_DATA entry
+ * if the database is empty.
+ */
+_PUBLIC_ TDB_DATA tdb_firstkey(struct tdb_context *tdb);
+
+/**
+ * @brief Find the next entry in the database, returning its key.
+ *
+ * The caller must free the returned data.
+ *
+ * @param[in] tdb The database to use.
+ *
+ * @param[in] key The key from which you want the next key.
+ *
+ * @return The next entry of the current key, an empty TDB_DATA
+ * entry if there is no entry.
+ */
+_PUBLIC_ TDB_DATA tdb_nextkey(struct tdb_context *tdb, TDB_DATA key);
+
+/**
+ * @brief Traverse the entire database.
+ *
+ * While traversing the function fn(tdb, key, data, state) is called on each
+ * element. If fn is NULL then it is not called. A non-zero return value from
+ * fn() indicates that the traversal should stop. Traversal callbacks may not
+ * start transactions.
+ *
+ * @warning The data buffer given to the callback fn does NOT meet the alignment
+ * restrictions malloc gives you.
+ *
+ * @param[in] tdb The database to traverse.
+ *
+ * @param[in] fn The function to call on each entry.
+ *
+ * @param[in] private_data The private data which should be passed to the
+ * traversing function.
+ *
+ * @return The record count traversed, -1 on error.
+ */
+_PUBLIC_ int tdb_traverse(struct tdb_context *tdb, tdb_traverse_func fn, void *private_data);
+
+/**
+ * @brief Traverse the entire database.
+ *
+ * While traversing the database the function fn(tdb, key, data, state) is
+ * called on each element, but marking the database read only during the
+ * traversal, so any write operations will fail. This allows tdb to use read
+ * locks, which increases the parallelism possible during the traversal.
+ *
+ * @param[in] tdb The database to traverse.
+ *
+ * @param[in] fn The function to call on each entry.
+ *
+ * @param[in] private_data The private data which should be passed to the
+ * traversing function.
+ *
+ * @return The record count traversed, -1 on error.
+ */
+_PUBLIC_ int tdb_traverse_read(struct tdb_context *tdb, tdb_traverse_func fn, void *private_data);
+
+/**
+ * @brief Traverse a single hash chain
+ *
+ * Traverse a single hash chain under a single lock operation. No
+ * database modification is possible in the callback.
+ *
+ * This exists for background cleanup of databases. In normal
+ * operations, traversing a complete database can be much too
+ * expensive. Databases can have many chains, which will all have to
+ * be looked at before tdb_traverse finishes. Also tdb_traverse does a
+ * lot of fcntl activity to protect against concurrent record deletes.
+ *
+ * With this you can walk a fraction of the whole tdb, collect the
+ * entries you want to prune, leave the traverse, and then modify or
+ * delete the records in a subsequent step.
+ *
+ * To walk the entire database, call this function tdb_hash_size()
+ * times, with 0<=chain<tdb_hash_size(tdb).
+ *
+ * @param[in] tdb The database to traverse.
+ *
+ * @param[in] chain The hash chain number to traverse.
+ *
+ * @param[in] fn The function to call on each entry.
+ *
+ * @param[in] private_data The private data which should be passed to the
+ * traversing function.
+ *
+ * @return The record count traversed, -1 on error.
+ */
+
+_PUBLIC_ int tdb_traverse_chain(struct tdb_context *tdb,
+ unsigned chain,
+ tdb_traverse_func fn,
+ void *private_data);
+
+/**
+ * @brief Traverse a single hash chain
+ *
+ * This is like tdb_traverse_chain(), but for all records that are in
+ * the same chain as the record corresponding to the key parameter.
+ *
+ * Use it for ongoing database maintenance under a lock. Whenever you
+ * are about to modify a database, you know which record you are going
+ * to write to. For that tdb_store(), an exclusive chainlock is taken
+ * behind the scenes. To utilize this exclusive lock for incremental
+ * database cleanup as well, tdb_chainlock() the key you are about to
+ * modify, then tdb_traverse_key_chain() to do the incremental
+ * maintenance, modify your record and tdb_chainunlock() the key
+ * again.
+ *
+ * @param[in] tdb The database to traverse.
+ *
+ * @param[in] key The record key to walk the chain for.
+ *
+ * @param[in] fn The function to call on each entry.
+ *
+ * @param[in] private_data The private data which should be passed to the
+ * traversing function.
+ *
+ * @return The record count traversed, -1 on error.
+ */
+
+_PUBLIC_ int tdb_traverse_key_chain(struct tdb_context *tdb,
+ TDB_DATA key,
+ tdb_traverse_func fn,
+ void *private_data);
+/**
+ * @brief Check if an entry in the database exists.
+ *
+ * @note 1 is returned if the key is found and 0 is returned if not found this
+ * doesn't match the conventions in the rest of this module, but is compatible
+ * with gdbm.
+ *
+ * @param[in] tdb The database to check if the entry exists.
+ *
+ * @param[in] key The key to check if the entry exists.
+ *
+ * @return 1 if the key is found, 0 if not.
+ */
+_PUBLIC_ int tdb_exists(struct tdb_context *tdb, TDB_DATA key);
+
+/**
+ * @brief Lock entire database with a write lock.
+ *
+ * @param[in] tdb The database to lock.
+ *
+ * @return 0 on success, -1 on error with error code set.
+ *
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ */
+_PUBLIC_ int tdb_lockall(struct tdb_context *tdb);
+
+/**
+ * @brief Lock entire database with a write lock.
+ *
+ * This is the non-blocking call.
+ *
+ * @param[in] tdb The database to lock.
+ *
+ * @return 0 on success, -1 on error with error code set.
+ *
+ * @see tdb_lockall()
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ */
+_PUBLIC_ int tdb_lockall_nonblock(struct tdb_context *tdb);
+
+/**
+ * @brief Unlock entire database with write lock.
+ *
+ * @param[in] tdb The database to unlock.
+ *
+ * @return 0 on success, -1 on error with error code set.
+ *
+ * @see tdb_lockall()
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ */
+_PUBLIC_ int tdb_unlockall(struct tdb_context *tdb);
+
+/**
+ * @brief Lock entire database with a read lock.
+ *
+ * @param[in] tdb The database to lock.
+ *
+ * @return 0 on success, -1 on error with error code set.
+ *
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ */
+_PUBLIC_ int tdb_lockall_read(struct tdb_context *tdb);
+
+/**
+ * @brief Lock entire database with a read lock.
+ *
+ * This is the non-blocking call.
+ *
+ * @param[in] tdb The database to lock.
+ *
+ * @return 0 on success, -1 on error with error code set.
+ *
+ * @see tdb_lockall_read()
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ */
+_PUBLIC_ int tdb_lockall_read_nonblock(struct tdb_context *tdb);
+
+/**
+ * @brief Unlock entire database with read lock.
+ *
+ * @param[in] tdb The database to unlock.
+ *
+ * @return 0 on success, -1 on error with error code set.
+ *
+ * @see tdb_lockall_read()
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ */
+_PUBLIC_ int tdb_unlockall_read(struct tdb_context *tdb);
+
+/**
+ * @brief Lock entire database with write lock - mark only.
+ *
+ * @todo Add more details.
+ *
+ * @param[in] tdb The database to mark.
+ *
+ * @return 0 on success, -1 on error with error code set.
+ *
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ */
+_PUBLIC_ int tdb_lockall_mark(struct tdb_context *tdb);
+
+/**
+ * @brief Lock entire database with write lock - unmark only.
+ *
+ * @todo Add more details.
+ *
+ * @param[in] tdb The database to mark.
+ *
+ * @return 0 on success, -1 on error with error code set.
+ *
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ */
+_PUBLIC_ int tdb_lockall_unmark(struct tdb_context *tdb);
+
+/**
+ * @brief Get the name of the current tdb file.
+ *
+ * This is useful for external logging functions.
+ *
+ * @param[in] tdb The database to get the name from.
+ *
+ * @return The name of the database.
+ */
+_PUBLIC_ const char *tdb_name(struct tdb_context *tdb);
+
+/**
+ * @brief Get the underlying file descriptor being used by tdb.
+ *
+ * This is useful for external routines that want to check the device/inode
+ * of the fd.
+ *
+ * @param[in] tdb The database to get the fd from.
+ *
+ * @return The file descriptor or -1.
+ */
+_PUBLIC_ int tdb_fd(struct tdb_context *tdb);
+
+/**
+ * @brief Get the current logging function.
+ *
+ * This is useful for external tdb routines that wish to log tdb errors.
+ *
+ * @param[in] tdb The database to get the logging function from.
+ *
+ * @return The logging function of the database.
+ *
+ * @see tdb_get_logging_private()
+ */
+_PUBLIC_ tdb_log_func tdb_log_fn(struct tdb_context *tdb);
+
+/**
+ * @brief Get the private data of the logging function.
+ *
+ * @param[in] tdb The database to get the data from.
+ *
+ * @return The private data pointer of the logging function.
+ *
+ * @see tdb_log_fn()
+ */
+_PUBLIC_ void *tdb_get_logging_private(struct tdb_context *tdb);
+
+/**
+ * @brief Is a transaction active?
+ *
+ * It is helpful for the application to know if a transaction is
+ * active, rather than needing to maintain an application-level reference
+ * count.
+ *
+ * @param[in] tdb The database to start the transaction.
+ *
+ * @return true if there is a transaction active, false otherwise
+ *
+ * @see tdb_transaction_start()
+ * @see tdb_transaction_prepare_commit()
+ * @see tdb_transaction_commit()
+ * @see tdb_transaction_cancel()
+ */
+_PUBLIC_ bool tdb_transaction_active(struct tdb_context *tdb);
+
+/**
+ * @brief Start a transaction.
+ *
+ * All operations after the transaction start can either be committed with
+ * tdb_transaction_commit() or cancelled with tdb_transaction_cancel().
+ *
+ * If (the default) TDB_ALLOW_NESTING was specified or
+ * TDB_DISALLOW_NESTING was not specified as a flag via tdb_open() or
+ * tdb_open_ex(), you call tdb_transaction_start() again on the same
+ * tdb context while a transaction is in progress, then the same
+ * transaction buffer is re-used. The number of
+ * tdb_transaction_{commit,cancel} operations must match the number of
+ * successful tdb_transaction_start() calls.
+ *
+ * Note that transactions are by default disk synchronous, and use a recover
+ * area in the database to automatically recover the database on the next open
+ * if the system crashes during a transaction. You can disable the synchronous
+ * transaction recovery setup using the TDB_NOSYNC flag, which will greatly
+ * speed up operations at the risk of corrupting your database if the system
+ * crashes.
+ *
+ * Operations made within a transaction are not visible to other users of the
+ * database until a successful commit.
+ *
+ * @param[in] tdb The database to start the transaction.
+ *
+ * @return 0 on success, -1 on error with error code set.
+ *
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ */
+_PUBLIC_ int tdb_transaction_start(struct tdb_context *tdb);
+
+/**
+ * @brief Start a transaction, non-blocking.
+ *
+ * @param[in] tdb The database to start the transaction.
+ *
+ * @return 0 on success, -1 on error with error code set.
+ *
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ * @see tdb_transaction_start()
+ */
+_PUBLIC_ int tdb_transaction_start_nonblock(struct tdb_context *tdb);
+
+/**
+ * @brief Prepare to commit a current transaction, for two-phase commits.
+ *
+ * Once prepared for commit, the only allowed calls are tdb_transaction_commit()
+ * or tdb_transaction_cancel(). Preparing allocates disk space for the pending
+ * updates, so a subsequent commit should succeed (barring any hardware
+ * failures).
+ *
+ * @param[in] tdb The database to prepare the commit.
+ *
+ * @return 0 on success, -1 on error with error code set.
+ *
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ */
+_PUBLIC_ int tdb_transaction_prepare_commit(struct tdb_context *tdb);
+
+/**
+ * @brief Commit a current transaction.
+ *
+ * This updates the database and releases the current transaction locks.
+ *
+ * @param[in] tdb The database to commit the transaction.
+ *
+ * @return 0 on success, -1 on error with error code set.
+ *
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ */
+_PUBLIC_ int tdb_transaction_commit(struct tdb_context *tdb);
+
+/**
+ * @brief Cancel a current transaction.
+ *
+ * This discards all write and lock operations that have been made since the
+ * transaction started.
+ *
+ * @param[in] tdb The tdb to cancel the transaction on.
+ *
+ * @return 0 on success, -1 on error with error code set.
+ *
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ */
+_PUBLIC_ int tdb_transaction_cancel(struct tdb_context *tdb);
+
+/**
+ * @brief Get the tdb sequence number.
+ *
+ * Only makes sense if the writers opened with TDB_SEQNUM set. Note that this
+ * sequence number will wrap quite quickly, so it should only be used for a
+ * 'has something changed' test, not for code that relies on the count of the
+ * number of changes made. If you want a counter then use a tdb record.
+ *
+ * The aim of this sequence number is to allow for a very lightweight test of a
+ * possible tdb change.
+ *
+ * @param[in] tdb The database to get the sequence number from.
+ *
+ * @return The sequence number or 0.
+ *
+ * @see tdb_open()
+ * @see tdb_enable_seqnum()
+ */
+_PUBLIC_ int tdb_get_seqnum(struct tdb_context *tdb);
+
+/**
+ * @brief Get the hash size.
+ *
+ * @param[in] tdb The database to get the hash size from.
+ *
+ * @return The hash size.
+ */
+_PUBLIC_ int tdb_hash_size(struct tdb_context *tdb);
+
+/**
+ * @brief Get the map size.
+ *
+ * @param[in] tdb The database to get the map size from.
+ *
+ * @return The map size.
+ */
+_PUBLIC_ size_t tdb_map_size(struct tdb_context *tdb);
+
+/**
+ * @brief Get the tdb flags set during open.
+ *
+ * @param[in] tdb The database to get the flags form.
+ *
+ * @return The flags set to on the database.
+ */
+_PUBLIC_ int tdb_get_flags(struct tdb_context *tdb);
+
+/**
+ * @brief Add flags to the database.
+ *
+ * @param[in] tdb The database to add the flags.
+ *
+ * @param[in] flag The tdb flags to add.
+ */
+_PUBLIC_ void tdb_add_flags(struct tdb_context *tdb, unsigned flag);
+
+/**
+ * @brief Remove flags from the database.
+ *
+ * @param[in] tdb The database to remove the flags.
+ *
+ * @param[in] flag The tdb flags to remove.
+ */
+_PUBLIC_ void tdb_remove_flags(struct tdb_context *tdb, unsigned flag);
+
+/**
+ * @brief Enable sequence number handling on an open tdb.
+ *
+ * @param[in] tdb The database to enable sequence number handling.
+ *
+ * @see tdb_get_seqnum()
+ */
+_PUBLIC_ void tdb_enable_seqnum(struct tdb_context *tdb);
+
+/**
+ * @brief Increment the tdb sequence number.
+ *
+ * This only works if the tdb has been opened using the TDB_SEQNUM flag or
+ * enabled using tdb_enable_seqnum().
+ *
+ * @param[in] tdb The database to increment the sequence number.
+ *
+ * @see tdb_enable_seqnum()
+ * @see tdb_get_seqnum()
+ */
+_PUBLIC_ void tdb_increment_seqnum_nonblock(struct tdb_context *tdb);
+
+/**
+ * @brief Create a hash of the key.
+ *
+ * @param[in] key The key to hash
+ *
+ * @return The hash.
+ */
+_PUBLIC_ unsigned int tdb_jenkins_hash(TDB_DATA *key);
+
+/**
+ * @brief Check the consistency of the database.
+ *
+ * This check the consistency of the database calling back the check function
+ * (if non-NULL) on each record. If some consistency check fails, or the
+ * supplied check function returns -1, tdb_check returns -1, otherwise 0.
+ *
+ * @note The logging function (if set) will be called with additional
+ * information on the corruption found.
+ *
+ * @param[in] tdb The database to check.
+ *
+ * @param[in] check The check function to use.
+ *
+ * @param[in] private_data the private data to pass to the check function.
+ *
+ * @return 0 on success, -1 on error with error code set.
+ *
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ */
+_PUBLIC_ int tdb_check(struct tdb_context *tdb,
+ int (*check) (TDB_DATA key, TDB_DATA data, void *private_data),
+ void *private_data);
+
+/**
+ * @brief Dump all possible records in a corrupt database.
+ *
+ * This is the only way to get data out of a database where tdb_check() fails.
+ * It will call walk() with anything which looks like a database record; this
+ * may well include invalid, incomplete or duplicate records.
+ *
+ * @param[in] tdb The database to check.
+ *
+ * @param[in] walk The walk function to use.
+ *
+ * @param[in] private_data the private data to pass to the walk function.
+ *
+ * @return 0 on success, -1 on error with error code set.
+ *
+ * @see tdb_error()
+ * @see tdb_errorstr()
+ */
+_PUBLIC_ int tdb_rescue(struct tdb_context *tdb,
+ void (*walk) (TDB_DATA key, TDB_DATA data, void *private_data),
+ void *private_data);
+
+/**
+ * @brief Check if support for TDB_MUTEX_LOCKING is available at runtime.
+ *
+ * On some systems the API for pthread_mutexattr_setrobust() is not available.
+ * On other systems there are some bugs in the interaction between glibc and
+ * the linux kernel.
+ *
+ * This function provides a runtime check if robust mutexes are really
+ * available.
+ *
+ * This needs to be called and return true before TDB_MUTEX_LOCKING
+ * can be used at runtime.
+ *
+ * @note This calls fork(), but the SIGCHILD handling should be transparent.
+ *
+ * @return true if supported, false otherwise.
+ *
+ * @see TDB_MUTEX_LOCKING
+ */
+_PUBLIC_ bool tdb_runtime_check_for_robust_mutexes(void);
+
+/* @} ******************************************************************/
+
+/* Low level locking functions: use with care */
+_PUBLIC_ int tdb_chainlock(struct tdb_context *tdb, TDB_DATA key);
+_PUBLIC_ int tdb_chainlock_nonblock(struct tdb_context *tdb, TDB_DATA key);
+_PUBLIC_ int tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key);
+_PUBLIC_ int tdb_chainlock_read(struct tdb_context *tdb, TDB_DATA key);
+_PUBLIC_ int tdb_chainlock_read_nonblock(struct tdb_context *tdb, TDB_DATA key);
+_PUBLIC_ int tdb_chainunlock_read(struct tdb_context *tdb, TDB_DATA key);
+_PUBLIC_ int tdb_chainlock_mark(struct tdb_context *tdb, TDB_DATA key);
+_PUBLIC_ int tdb_chainlock_unmark(struct tdb_context *tdb, TDB_DATA key);
+
+_PUBLIC_ void tdb_setalarm_sigptr(struct tdb_context *tdb, volatile sig_atomic_t *sigptr);
+
+/* wipe and repack */
+_PUBLIC_ int tdb_wipe_all(struct tdb_context *tdb);
+_PUBLIC_ int tdb_repack(struct tdb_context *tdb);
+
+/* Debug functions. Not used in production. */
+_PUBLIC_ void tdb_dump_all(struct tdb_context *tdb);
+_PUBLIC_ int tdb_printfreelist(struct tdb_context *tdb);
+_PUBLIC_ int tdb_validate_freelist(struct tdb_context *tdb, int *pnum_entries);
+_PUBLIC_ int tdb_freelist_size(struct tdb_context *tdb);
+_PUBLIC_ char *tdb_summary(struct tdb_context *tdb);
+
+_PUBLIC_ extern TDB_DATA tdb_null;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* tdb.h */