Apache Portable Runtime
apr_proc_mutex.h
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16 
17 #ifndef APR_PROC_MUTEX_H
18 #define APR_PROC_MUTEX_H
19 
20 /**
21  * @file apr_proc_mutex.h
22  * @brief APR Process Locking Routines
23  */
24 
25 #include "apr.h"
26 #include "apr_pools.h"
27 #include "apr_errno.h"
28 #include "apr_perms_set.h"
29 #include "apr_time.h"
30 
31 #ifdef __cplusplus
32 extern "C" {
33 #endif /* __cplusplus */
34 
35 /**
36  * @defgroup apr_proc_mutex Process Locking Routines
37  * @ingroup APR
38  * @{
39  */
40 
41 /**
42  * Enumerated potential types for APR process locking methods
43  * @warning Check APR_HAS_foo_SERIALIZE defines to see if the platform supports
44  * APR_LOCK_foo. Only APR_LOCK_DEFAULT is portable.
45  */
46 typedef enum {
47  APR_LOCK_FCNTL, /**< fcntl() */
48  APR_LOCK_FLOCK, /**< flock() */
49  APR_LOCK_SYSVSEM, /**< System V Semaphores */
50  APR_LOCK_PROC_PTHREAD, /**< POSIX pthread process-based locking */
51  APR_LOCK_POSIXSEM, /**< POSIX semaphore process-based locking */
52  APR_LOCK_DEFAULT, /**< Use the default process lock */
53  APR_LOCK_DEFAULT_TIMED /**< Use the default process timed lock */
55 
56 /** Opaque structure representing a process mutex. */
58 
59 /* Function definitions */
60 
61 /**
62  * Create and initialize a mutex that can be used to synchronize processes.
63  * @param mutex the memory address where the newly created mutex will be
64  * stored.
65  * @param fname A file name to use if the lock mechanism requires one. This
66  * argument should always be provided. The lock code itself will
67  * determine if it should be used.
68  * @param mech The mechanism to use for the interprocess lock, if any; one of
69  * <PRE>
70  * APR_LOCK_FCNTL
71  * APR_LOCK_FLOCK
72  * APR_LOCK_SYSVSEM
73  * APR_LOCK_POSIXSEM
74  * APR_LOCK_PROC_PTHREAD
75  * APR_LOCK_DEFAULT pick the default mechanism for the platform
76  * </PRE>
77  * @param pool the pool from which to allocate the mutex.
78  * @see apr_lockmech_e
79  * @warning Check APR_HAS_foo_SERIALIZE defines to see if the platform supports
80  * APR_LOCK_foo. Only APR_LOCK_DEFAULT is portable.
81  */
83  const char *fname,
84  apr_lockmech_e mech,
85  apr_pool_t *pool);
86 
87 /**
88  * Re-open a mutex in a child process.
89  * @param mutex The newly re-opened mutex structure.
90  * @param fname A file name to use if the mutex mechanism requires one. This
91  * argument should always be provided. The mutex code itself will
92  * determine if it should be used. This filename should be the
93  * same one that was passed to apr_proc_mutex_create().
94  * @param pool The pool to operate on.
95  * @remark This function must be called to maintain portability, even
96  * if the underlying lock mechanism does not require it.
97  */
99  const char *fname,
100  apr_pool_t *pool);
101 
102 /**
103  * Acquire the lock for the given mutex. If the mutex is already locked,
104  * the current thread will be put to sleep until the lock becomes available.
105  * @param mutex the mutex on which to acquire the lock.
106  */
108 
109 /**
110  * Attempt to acquire the lock for the given mutex. If the mutex has already
111  * been acquired, the call returns immediately with APR_EBUSY. Note: it
112  * is important that the APR_STATUS_IS_EBUSY(s) macro be used to determine
113  * if the return value was APR_EBUSY, for portability reasons.
114  * @param mutex the mutex on which to attempt the lock acquiring.
115  */
117 
118 /**
119  * Attempt to acquire the lock for the given mutex until timeout expires.
120  * If the acquisition time outs, the call returns with APR_TIMEUP.
121  * @param mutex the mutex on which to attempt the lock acquiring.
122  * @param timeout the absolute time or relative timeout (microseconds)
123  * @param absolute whether the timeout given is absolute (!0) or relative (0)
124  */
126  apr_time_t timeout,
127  int absolute);
128 
129 /**
130  * Release the lock for the given mutex.
131  * @param mutex the mutex from which to release the lock.
132  */
134 
135 /**
136  * Destroy the mutex and free the memory associated with the lock.
137  * @param mutex the mutex to destroy.
138  */
140 
141 /**
142  * Destroy the mutex and free the memory associated with the lock.
143  * @param mutex the mutex to destroy.
144  * @note This function is generally used to kill a cleanup on an already
145  * created mutex
146  */
148 
149 /**
150  * Return the name of the lockfile for the mutex, or NULL
151  * if the mutex doesn't use a lock file
152  */
153 
155 
156 /**
157  * Get the mechanism of the mutex, as it relates to the actual method
158  * used for the underlying apr_proc_mutex_t.
159  * @param mutex the mutex to get the mechanism from.
160  */
162 
163 /**
164  * Get the mechanism's name of the mutex, as it relates to the actual method
165  * used for the underlying apr_proc_mutex_t.
166  * @param mutex the mutex to get the mechanism's name from.
167  */
168 APR_DECLARE(const char *) apr_proc_mutex_name(apr_proc_mutex_t *mutex);
169 
170 /**
171  * Display the name of the default mutex: APR_LOCK_DEFAULT
172  */
173 APR_DECLARE(const char *) apr_proc_mutex_defname(void);
174 
175 /**
176  * Set mutex permissions.
177  */
178 APR_PERMS_SET_IMPLEMENT(proc_mutex);
179 
180 /**
181  * Get the pool used by this proc_mutex.
182  * @return apr_pool_t the pool
183  */
184 APR_POOL_DECLARE_ACCESSOR(proc_mutex);
185 
186 /** @} */
187 
188 #ifdef __cplusplus
189 }
190 #endif
191 
192 #endif /* ! APR_PROC_MUTEX_H */
Definition: apr_proc_mutex.h:49
APR Process Locking Routines.
const char * apr_proc_mutex_lockfile(apr_proc_mutex_t *mutex)
Definition: apr_proc_mutex.h:51
Definition: apr_proc_mutex.h:50
Definition: apr_proc_mutex.h:47
Definition: apr_proc_mutex.h:52
const char * apr_proc_mutex_defname(void)
apr_status_t apr_proc_mutex_child_init(apr_proc_mutex_t **mutex, const char *fname, apr_pool_t *pool)
Definition: apr_proc_mutex.h:48
struct apr_proc_mutex_t apr_proc_mutex_t
Definition: apr_proc_mutex.h:57
apr_int64_t apr_time_t
Definition: apr_time.h:45
APR memory allocation.
apr_status_t apr_proc_mutex_lock(apr_proc_mutex_t *mutex)
apr_status_t apr_proc_mutex_create(apr_proc_mutex_t **mutex, const char *fname, apr_lockmech_e mech, apr_pool_t *pool)
APR Error Codes.
#define APR_DECLARE(type)
Definition: apr.h:500
apr_lockmech_e
Definition: apr_proc_mutex.h:46
APR Platform Definitions.
const char * apr_proc_mutex_name(apr_proc_mutex_t *mutex)
APR_PERMS_SET_IMPLEMENT(proc_mutex)
apr_status_t apr_proc_mutex_unlock(apr_proc_mutex_t *mutex)
Definition: apr_proc_mutex.h:53
struct apr_pool_t apr_pool_t
Definition: apr_pools.h:60
apr_status_t apr_proc_mutex_destroy(apr_proc_mutex_t *mutex)
int apr_status_t
Definition: apr_errno.h:44
APR Time Library.
apr_lockmech_e apr_proc_mutex_mech(apr_proc_mutex_t *mutex)
apr_status_t apr_proc_mutex_cleanup(void *mutex)
apr_status_t apr_proc_mutex_trylock(apr_proc_mutex_t *mutex)
#define APR_POOL_DECLARE_ACCESSOR(type)
Definition: apr_pools.h:81
apr_status_t apr_proc_mutex_timedlock(apr_proc_mutex_t *mutex, apr_time_t timeout, int absolute)