1251875Speter/* Licensed to the Apache Software Foundation (ASF) under one or more 2251875Speter * contributor license agreements. See the NOTICE file distributed with 3251875Speter * this work for additional information regarding copyright ownership. 4251875Speter * The ASF licenses this file to You under the Apache License, Version 2.0 5251875Speter * (the "License"); you may not use this file except in compliance with 6251875Speter * the License. You may obtain a copy of the License at 7251875Speter * 8251875Speter * http://www.apache.org/licenses/LICENSE-2.0 9251875Speter * 10251875Speter * Unless required by applicable law or agreed to in writing, software 11251875Speter * distributed under the License is distributed on an "AS IS" BASIS, 12251875Speter * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13251875Speter * See the License for the specific language governing permissions and 14251875Speter * limitations under the License. 15251875Speter */ 16251875Speter 17251875Speter#ifndef APR_PROC_MUTEX_H 18251875Speter#define APR_PROC_MUTEX_H 19251875Speter 20251875Speter/** 21251875Speter * @file apr_proc_mutex.h 22251875Speter * @brief APR Process Locking Routines 23251875Speter */ 24251875Speter 25251875Speter#include "apr.h" 26251875Speter#include "apr_pools.h" 27251875Speter#include "apr_errno.h" 28362181Sdim#include "apr_perms_set.h" 29362181Sdim#include "apr_time.h" 30251875Speter 31251875Speter#ifdef __cplusplus 32251875Speterextern "C" { 33251875Speter#endif /* __cplusplus */ 34251875Speter 35251875Speter/** 36251875Speter * @defgroup apr_proc_mutex Process Locking Routines 37251875Speter * @ingroup APR 38251875Speter * @{ 39251875Speter */ 40251875Speter 41251875Speter/** 42251875Speter * Enumerated potential types for APR process locking methods 43251875Speter * @warning Check APR_HAS_foo_SERIALIZE defines to see if the platform supports 44251875Speter * APR_LOCK_foo. Only APR_LOCK_DEFAULT is portable. 45251875Speter */ 46251875Spetertypedef enum { 47251875Speter APR_LOCK_FCNTL, /**< fcntl() */ 48251875Speter APR_LOCK_FLOCK, /**< flock() */ 49251875Speter APR_LOCK_SYSVSEM, /**< System V Semaphores */ 50251875Speter APR_LOCK_PROC_PTHREAD, /**< POSIX pthread process-based locking */ 51251875Speter APR_LOCK_POSIXSEM, /**< POSIX semaphore process-based locking */ 52362181Sdim APR_LOCK_DEFAULT, /**< Use the default process lock */ 53362181Sdim APR_LOCK_DEFAULT_TIMED /**< Use the default process timed lock */ 54251875Speter} apr_lockmech_e; 55251875Speter 56251875Speter/** Opaque structure representing a process mutex. */ 57251875Spetertypedef struct apr_proc_mutex_t apr_proc_mutex_t; 58251875Speter 59251875Speter/* Function definitions */ 60251875Speter 61251875Speter/** 62251875Speter * Create and initialize a mutex that can be used to synchronize processes. 63251875Speter * @param mutex the memory address where the newly created mutex will be 64251875Speter * stored. 65251875Speter * @param fname A file name to use if the lock mechanism requires one. This 66251875Speter * argument should always be provided. The lock code itself will 67251875Speter * determine if it should be used. 68251875Speter * @param mech The mechanism to use for the interprocess lock, if any; one of 69251875Speter * <PRE> 70251875Speter * APR_LOCK_FCNTL 71251875Speter * APR_LOCK_FLOCK 72251875Speter * APR_LOCK_SYSVSEM 73251875Speter * APR_LOCK_POSIXSEM 74251875Speter * APR_LOCK_PROC_PTHREAD 75251875Speter * APR_LOCK_DEFAULT pick the default mechanism for the platform 76251875Speter * </PRE> 77251875Speter * @param pool the pool from which to allocate the mutex. 78251875Speter * @see apr_lockmech_e 79251875Speter * @warning Check APR_HAS_foo_SERIALIZE defines to see if the platform supports 80251875Speter * APR_LOCK_foo. Only APR_LOCK_DEFAULT is portable. 81251875Speter */ 82251875SpeterAPR_DECLARE(apr_status_t) apr_proc_mutex_create(apr_proc_mutex_t **mutex, 83251875Speter const char *fname, 84251875Speter apr_lockmech_e mech, 85251875Speter apr_pool_t *pool); 86251875Speter 87251875Speter/** 88251875Speter * Re-open a mutex in a child process. 89251875Speter * @param mutex The newly re-opened mutex structure. 90251875Speter * @param fname A file name to use if the mutex mechanism requires one. This 91251875Speter * argument should always be provided. The mutex code itself will 92251875Speter * determine if it should be used. This filename should be the 93251875Speter * same one that was passed to apr_proc_mutex_create(). 94251875Speter * @param pool The pool to operate on. 95251875Speter * @remark This function must be called to maintain portability, even 96251875Speter * if the underlying lock mechanism does not require it. 97251875Speter */ 98251875SpeterAPR_DECLARE(apr_status_t) apr_proc_mutex_child_init(apr_proc_mutex_t **mutex, 99251875Speter const char *fname, 100251875Speter apr_pool_t *pool); 101251875Speter 102251875Speter/** 103251875Speter * Acquire the lock for the given mutex. If the mutex is already locked, 104251875Speter * the current thread will be put to sleep until the lock becomes available. 105251875Speter * @param mutex the mutex on which to acquire the lock. 106251875Speter */ 107251875SpeterAPR_DECLARE(apr_status_t) apr_proc_mutex_lock(apr_proc_mutex_t *mutex); 108251875Speter 109251875Speter/** 110251875Speter * Attempt to acquire the lock for the given mutex. If the mutex has already 111251875Speter * been acquired, the call returns immediately with APR_EBUSY. Note: it 112251875Speter * is important that the APR_STATUS_IS_EBUSY(s) macro be used to determine 113251875Speter * if the return value was APR_EBUSY, for portability reasons. 114251875Speter * @param mutex the mutex on which to attempt the lock acquiring. 115251875Speter */ 116251875SpeterAPR_DECLARE(apr_status_t) apr_proc_mutex_trylock(apr_proc_mutex_t *mutex); 117251875Speter 118251875Speter/** 119362181Sdim * Attempt to acquire the lock for the given mutex until timeout expires. 120362181Sdim * If the acquisition time outs, the call returns with APR_TIMEUP. 121362181Sdim * @param mutex the mutex on which to attempt the lock acquiring. 122362181Sdim * @param timeout the relative timeout (microseconds). 123362181Sdim * @note A negative or nul timeout means immediate attempt, returning 124362181Sdim * APR_TIMEUP without blocking if it the lock is already acquired. 125362181Sdim */ 126362181SdimAPR_DECLARE(apr_status_t) apr_proc_mutex_timedlock(apr_proc_mutex_t *mutex, 127362181Sdim apr_interval_time_t timeout); 128362181Sdim 129362181Sdim/** 130251875Speter * Release the lock for the given mutex. 131251875Speter * @param mutex the mutex from which to release the lock. 132251875Speter */ 133251875SpeterAPR_DECLARE(apr_status_t) apr_proc_mutex_unlock(apr_proc_mutex_t *mutex); 134251875Speter 135251875Speter/** 136251875Speter * Destroy the mutex and free the memory associated with the lock. 137251875Speter * @param mutex the mutex to destroy. 138251875Speter */ 139251875SpeterAPR_DECLARE(apr_status_t) apr_proc_mutex_destroy(apr_proc_mutex_t *mutex); 140251875Speter 141251875Speter/** 142251875Speter * Destroy the mutex and free the memory associated with the lock. 143251875Speter * @param mutex the mutex to destroy. 144251875Speter * @note This function is generally used to kill a cleanup on an already 145251875Speter * created mutex 146251875Speter */ 147251875SpeterAPR_DECLARE(apr_status_t) apr_proc_mutex_cleanup(void *mutex); 148251875Speter 149251875Speter/** 150251875Speter * Return the name of the lockfile for the mutex, or NULL 151251875Speter * if the mutex doesn't use a lock file 152251875Speter */ 153251875Speter 154251875SpeterAPR_DECLARE(const char *) apr_proc_mutex_lockfile(apr_proc_mutex_t *mutex); 155251875Speter 156251875Speter/** 157362181Sdim * Get the mechanism of the mutex, as it relates to the actual method 158362181Sdim * used for the underlying apr_proc_mutex_t. 159362181Sdim * @param mutex the mutex to get the mechanism from. 160251875Speter */ 161362181SdimAPR_DECLARE(apr_lockmech_e) apr_proc_mutex_mech(apr_proc_mutex_t *mutex); 162362181Sdim 163362181Sdim/** 164362181Sdim * Get the mechanism's name of the mutex, as it relates to the actual method 165362181Sdim * used for the underlying apr_proc_mutex_t. 166362181Sdim * @param mutex the mutex to get the mechanism's name from. 167362181Sdim */ 168251875SpeterAPR_DECLARE(const char *) apr_proc_mutex_name(apr_proc_mutex_t *mutex); 169251875Speter 170251875Speter/** 171251875Speter * Display the name of the default mutex: APR_LOCK_DEFAULT 172251875Speter */ 173251875SpeterAPR_DECLARE(const char *) apr_proc_mutex_defname(void); 174251875Speter 175251875Speter/** 176362181Sdim * Set mutex permissions. 177362181Sdim */ 178362181SdimAPR_PERMS_SET_IMPLEMENT(proc_mutex); 179362181Sdim 180362181Sdim/** 181251875Speter * Get the pool used by this proc_mutex. 182251875Speter * @return apr_pool_t the pool 183251875Speter */ 184251875SpeterAPR_POOL_DECLARE_ACCESSOR(proc_mutex); 185251875Speter 186251875Speter/** @} */ 187251875Speter 188251875Speter#ifdef __cplusplus 189251875Speter} 190251875Speter#endif 191251875Speter 192251875Speter#endif /* ! APR_PROC_MUTEX_H */ 193