apr_proc_mutex.h revision 251875
1187767Sluigi/* Licensed to the Apache Software Foundation (ASF) under one or more 2187767Sluigi * contributor license agreements. See the NOTICE file distributed with 3187767Sluigi * this work for additional information regarding copyright ownership. 4187767Sluigi * The ASF licenses this file to You under the Apache License, Version 2.0 5187767Sluigi * (the "License"); you may not use this file except in compliance with 6187767Sluigi * the License. You may obtain a copy of the License at 7187767Sluigi * 8187767Sluigi * http://www.apache.org/licenses/LICENSE-2.0 9187767Sluigi * 10187767Sluigi * Unless required by applicable law or agreed to in writing, software 11187767Sluigi * distributed under the License is distributed on an "AS IS" BASIS, 12187767Sluigi * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13187767Sluigi * See the License for the specific language governing permissions and 14187767Sluigi * limitations under the License. 15187767Sluigi */ 16187767Sluigi 17187767Sluigi#ifndef APR_PROC_MUTEX_H 18187767Sluigi#define APR_PROC_MUTEX_H 19187767Sluigi 20187767Sluigi/** 21187767Sluigi * @file apr_proc_mutex.h 22187767Sluigi * @brief APR Process Locking Routines 23187767Sluigi */ 24187767Sluigi 25187767Sluigi#include "apr.h" 26187767Sluigi#include "apr_pools.h" 27187767Sluigi#include "apr_errno.h" 28187767Sluigi 29187767Sluigi#ifdef __cplusplus 30187767Sluigiextern "C" { 31187767Sluigi#endif /* __cplusplus */ 32187767Sluigi 33187767Sluigi/** 34187767Sluigi * @defgroup apr_proc_mutex Process Locking Routines 35187767Sluigi * @ingroup APR 36187767Sluigi * @{ 37187767Sluigi */ 38204591Sluigi 39187767Sluigi/** 40187767Sluigi * Enumerated potential types for APR process locking methods 41187767Sluigi * @warning Check APR_HAS_foo_SERIALIZE defines to see if the platform supports 42187767Sluigi * APR_LOCK_foo. Only APR_LOCK_DEFAULT is portable. 43187767Sluigi */ 44187767Sluigitypedef enum { 45187767Sluigi APR_LOCK_FCNTL, /**< fcntl() */ 46187767Sluigi APR_LOCK_FLOCK, /**< flock() */ 47187767Sluigi APR_LOCK_SYSVSEM, /**< System V Semaphores */ 48187767Sluigi APR_LOCK_PROC_PTHREAD, /**< POSIX pthread process-based locking */ 49187767Sluigi APR_LOCK_POSIXSEM, /**< POSIX semaphore process-based locking */ 50187767Sluigi APR_LOCK_DEFAULT /**< Use the default process lock */ 51187767Sluigi} apr_lockmech_e; 52187767Sluigi 53187767Sluigi/** Opaque structure representing a process mutex. */ 54187767Sluigitypedef struct apr_proc_mutex_t apr_proc_mutex_t; 55187767Sluigi 56187767Sluigi/* Function definitions */ 57187767Sluigi 58187767Sluigi/** 59187767Sluigi * Create and initialize a mutex that can be used to synchronize processes. 60187767Sluigi * @param mutex the memory address where the newly created mutex will be 61187767Sluigi * stored. 62187767Sluigi * @param fname A file name to use if the lock mechanism requires one. This 63187767Sluigi * argument should always be provided. The lock code itself will 64187767Sluigi * determine if it should be used. 65187767Sluigi * @param mech The mechanism to use for the interprocess lock, if any; one of 66187767Sluigi * <PRE> 67187767Sluigi * APR_LOCK_FCNTL 68187767Sluigi * APR_LOCK_FLOCK 69187767Sluigi * APR_LOCK_SYSVSEM 70187767Sluigi * APR_LOCK_POSIXSEM 71187767Sluigi * APR_LOCK_PROC_PTHREAD 72187767Sluigi * APR_LOCK_DEFAULT pick the default mechanism for the platform 73187767Sluigi * </PRE> 74187769Sluigi * @param pool the pool from which to allocate the mutex. 75187769Sluigi * @see apr_lockmech_e 76187769Sluigi * @warning Check APR_HAS_foo_SERIALIZE defines to see if the platform supports 77187769Sluigi * APR_LOCK_foo. Only APR_LOCK_DEFAULT is portable. 78187769Sluigi */ 79187769SluigiAPR_DECLARE(apr_status_t) apr_proc_mutex_create(apr_proc_mutex_t **mutex, 80187769Sluigi const char *fname, 81187769Sluigi apr_lockmech_e mech, 82187769Sluigi apr_pool_t *pool); 83187769Sluigi 84187769Sluigi/** 85204591Sluigi * Re-open a mutex in a child process. 86187769Sluigi * @param mutex The newly re-opened mutex structure. 87204591Sluigi * @param fname A file name to use if the mutex mechanism requires one. This 88204591Sluigi * argument should always be provided. The mutex code itself will 89187769Sluigi * determine if it should be used. This filename should be the 90187769Sluigi * same one that was passed to apr_proc_mutex_create(). 91187769Sluigi * @param pool The pool to operate on. 92187769Sluigi * @remark This function must be called to maintain portability, even 93187769Sluigi * if the underlying lock mechanism does not require it. 94187769Sluigi */ 95187769SluigiAPR_DECLARE(apr_status_t) apr_proc_mutex_child_init(apr_proc_mutex_t **mutex, 96187769Sluigi const char *fname, 97187769Sluigi apr_pool_t *pool); 98187769Sluigi 99187769Sluigi/** 100187769Sluigi * Acquire the lock for the given mutex. If the mutex is already locked, 101190633Spiso * the current thread will be put to sleep until the lock becomes available. 102223666Sae * @param mutex the mutex on which to acquire the lock. 103223666Sae */ 104187769SluigiAPR_DECLARE(apr_status_t) apr_proc_mutex_lock(apr_proc_mutex_t *mutex); 105187769Sluigi 106187769Sluigi/** 107187769Sluigi * Attempt to acquire the lock for the given mutex. If the mutex has already 108187769Sluigi * been acquired, the call returns immediately with APR_EBUSY. Note: it 109187769Sluigi * is important that the APR_STATUS_IS_EBUSY(s) macro be used to determine 110187769Sluigi * if the return value was APR_EBUSY, for portability reasons. 111187769Sluigi * @param mutex the mutex on which to attempt the lock acquiring. 112187769Sluigi */ 113187769SluigiAPR_DECLARE(apr_status_t) apr_proc_mutex_trylock(apr_proc_mutex_t *mutex); 114187769Sluigi 115187769Sluigi/** 116187769Sluigi * Release the lock for the given mutex. 117187769Sluigi * @param mutex the mutex from which to release the lock. 118187769Sluigi */ 119187769SluigiAPR_DECLARE(apr_status_t) apr_proc_mutex_unlock(apr_proc_mutex_t *mutex); 120187769Sluigi 121187769Sluigi/** 122187769Sluigi * Destroy the mutex and free the memory associated with the lock. 123187769Sluigi * @param mutex the mutex to destroy. 124187769Sluigi */ 125187769SluigiAPR_DECLARE(apr_status_t) apr_proc_mutex_destroy(apr_proc_mutex_t *mutex); 126187769Sluigi 127187769Sluigi/** 128187769Sluigi * Destroy the mutex and free the memory associated with the lock. 129187769Sluigi * @param mutex the mutex to destroy. 130205169Sluigi * @note This function is generally used to kill a cleanup on an already 131187769Sluigi * created mutex 132187769Sluigi */ 133187769SluigiAPR_DECLARE(apr_status_t) apr_proc_mutex_cleanup(void *mutex); 134187769Sluigi 135187769Sluigi/** 136187769Sluigi * Return the name of the lockfile for the mutex, or NULL 137187769Sluigi * if the mutex doesn't use a lock file 138187769Sluigi */ 139187769Sluigi 140187769SluigiAPR_DECLARE(const char *) apr_proc_mutex_lockfile(apr_proc_mutex_t *mutex); 141187769Sluigi 142187769Sluigi/** 143187769Sluigi * Display the name of the mutex, as it relates to the actual method used. 144187769Sluigi * This matches the valid options for Apache's AcceptMutex directive 145187769Sluigi * @param mutex the name of the mutex 146187769Sluigi */ 147187769SluigiAPR_DECLARE(const char *) apr_proc_mutex_name(apr_proc_mutex_t *mutex); 148187769Sluigi 149187769Sluigi/** 150187769Sluigi * Display the name of the default mutex: APR_LOCK_DEFAULT 151187769Sluigi */ 152187769SluigiAPR_DECLARE(const char *) apr_proc_mutex_defname(void); 153187769Sluigi 154187769Sluigi/** 155187769Sluigi * Get the pool used by this proc_mutex. 156187769Sluigi * @return apr_pool_t the pool 157187769Sluigi */ 158187769SluigiAPR_POOL_DECLARE_ACCESSOR(proc_mutex); 159187769Sluigi 160204591Sluigi/** @} */ 161204591Sluigi 162187769Sluigi#ifdef __cplusplus 163187769Sluigi} 164204591Sluigi#endif 165194930Soleg 166187769Sluigi#endif /* ! APR_PROC_MUTEX_H */ 167187769Sluigi