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- /* Copyright 2000-2005 The Apache Software Foundation or its licensors, as
- * applicable.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
- #ifndef APR_PROC_MUTEX_H
- #define APR_PROC_MUTEX_H
-
- /**
- * @file apr_proc_mutex.h
- * @brief APR Process Locking Routines
- */
-
- #include "apr.h"
- #include "apr_pools.h"
- #include "apr_errno.h"
-
- #ifdef __cplusplus
- extern "C" {
- #endif /* __cplusplus */
-
- /**
- * @defgroup apr_proc_mutex Process Locking Routines
- * @ingroup APR
- * @{
- */
-
- /**
- * Enumerated potential types for APR process locking methods
- * @warning Check APR_HAS_foo_SERIALIZE defines to see if the platform supports
- * APR_LOCK_foo. Only APR_LOCK_DEFAULT is portable.
- */
- typedef enum {
- APR_LOCK_FCNTL, /**< fcntl() */
- APR_LOCK_FLOCK, /**< flock() */
- APR_LOCK_SYSVSEM, /**< System V Semaphores */
- APR_LOCK_PROC_PTHREAD, /**< POSIX pthread process-based locking */
- APR_LOCK_POSIXSEM, /**< POSIX semaphore process-based locking */
- APR_LOCK_DEFAULT /**< Use the default process lock */
- } apr_lockmech_e;
-
- /** Opaque structure representing a process mutex. */
- typedef struct apr_proc_mutex_t apr_proc_mutex_t;
-
- /* Function definitions */
-
- /**
- * Create and initialize a mutex that can be used to synchronize processes.
- * @param mutex the memory address where the newly created mutex will be
- * stored.
- * @param fname A file name to use if the lock mechanism requires one. This
- * argument should always be provided. The lock code itself will
- * determine if it should be used.
- * @param mech The mechanism to use for the interprocess lock, if any; one of
- * <PRE>
- * APR_LOCK_FCNTL
- * APR_LOCK_FLOCK
- * APR_LOCK_SYSVSEM
- * APR_LOCK_POSIXSEM
- * APR_LOCK_PROC_PTHREAD
- * APR_LOCK_DEFAULT pick the default mechanism for the platform
- * </PRE>
- * @param pool the pool from which to allocate the mutex.
- * @see apr_lockmech_e
- * @warning Check APR_HAS_foo_SERIALIZE defines to see if the platform supports
- * APR_LOCK_foo. Only APR_LOCK_DEFAULT is portable.
- */
- APR_DECLARE(apr_status_t) apr_proc_mutex_create(apr_proc_mutex_t **mutex,
- const char *fname,
- apr_lockmech_e mech,
- apr_pool_t *pool);
-
- /**
- * Re-open a mutex in a child process.
- * @param mutex The newly re-opened mutex structure.
- * @param fname A file name to use if the mutex mechanism requires one. This
- * argument should always be provided. The mutex code itself will
- * determine if it should be used. This filename should be the
- * same one that was passed to apr_proc_mutex_create().
- * @param pool The pool to operate on.
- * @remark This function must be called to maintain portability, even
- * if the underlying lock mechanism does not require it.
- */
- APR_DECLARE(apr_status_t) apr_proc_mutex_child_init(apr_proc_mutex_t **mutex,
- const char *fname,
- apr_pool_t *pool);
-
- /**
- * Acquire the lock for the given mutex. If the mutex is already locked,
- * the current thread will be put to sleep until the lock becomes available.
- * @param mutex the mutex on which to acquire the lock.
- */
- APR_DECLARE(apr_status_t) apr_proc_mutex_lock(apr_proc_mutex_t *mutex);
-
- /**
- * Attempt to acquire the lock for the given mutex. If the mutex has already
- * been acquired, the call returns immediately with APR_EBUSY. Note: it
- * is important that the APR_STATUS_IS_EBUSY(s) macro be used to determine
- * if the return value was APR_EBUSY, for portability reasons.
- * @param mutex the mutex on which to attempt the lock acquiring.
- */
- APR_DECLARE(apr_status_t) apr_proc_mutex_trylock(apr_proc_mutex_t *mutex);
-
- /**
- * Release the lock for the given mutex.
- * @param mutex the mutex from which to release the lock.
- */
- APR_DECLARE(apr_status_t) apr_proc_mutex_unlock(apr_proc_mutex_t *mutex);
-
- /**
- * Destroy the mutex and free the memory associated with the lock.
- * @param mutex the mutex to destroy.
- */
- APR_DECLARE(apr_status_t) apr_proc_mutex_destroy(apr_proc_mutex_t *mutex);
-
- /**
- * Destroy the mutex and free the memory associated with the lock.
- * @param mutex the mutex to destroy.
- * @note This function is generally used to kill a cleanup on an already
- * created mutex
- */
- APR_DECLARE(apr_status_t) apr_proc_mutex_cleanup(void *mutex);
-
- /**
- * Return the name of the lockfile for the mutex, or NULL
- * if the mutex doesn't use a lock file
- */
-
- APR_DECLARE(const char *) apr_proc_mutex_lockfile(apr_proc_mutex_t *mutex);
-
- /**
- * Display the name of the mutex, as it relates to the actual method used.
- * This matches the valid options for Apache's AcceptMutex directive
- * @param mutex the name of the mutex
- */
- APR_DECLARE(const char *) apr_proc_mutex_name(apr_proc_mutex_t *mutex);
-
- /**
- * Display the name of the default mutex: APR_LOCK_DEFAULT
- */
- APR_DECLARE(const char *) apr_proc_mutex_defname(void);
-
- /**
- * Get the pool used by this proc_mutex.
- * @return apr_pool_t the pool
- */
- APR_POOL_DECLARE_ACCESSOR(proc_mutex);
-
- /** @} */
-
- #ifdef __cplusplus
- }
- #endif
-
- #endif /* ! APR_PROC_MUTEX_H */
-