summaryrefslogtreecommitdiff
path: root/include/util_mutex.h
blob: 1cb89c867512cd684932c40c45d3f50cc947ae83 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

/**
 * @file  util_mutex.h
 * @brief Apache Mutex support library
 *
 * @defgroup APACHE_CORE_MUTEX Mutex Library
 * @ingroup  APACHE_CORE
 * @{
 */

#ifndef UTIL_MUTEX_H
#define UTIL_MUTEX_H

#include "httpd.h"
#include "http_config.h"
#include "apr_global_mutex.h"

#if APR_HAS_FLOCK_SERIALIZE
# define AP_LIST_FLOCK_SERIALIZE ", 'flock:/path/to/file'"
#else
# define AP_LIST_FLOCK_SERIALIZE
#endif
#if APR_HAS_FCNTL_SERIALIZE
# define AP_LIST_FCNTL_SERIALIZE ", 'fcntl:/path/to/file'"
#else
# define AP_LIST_FCNTL_SERIALIZE
#endif
#if APR_HAS_SYSVSEM_SERIALIZE
# define AP_LIST_SYSVSEM_SERIALIZE ", 'sysvsem'"
#else
# define AP_LIST_SYSVSEM_SERIALIZE
#endif
#if APR_HAS_POSIXSEM_SERIALIZE
# define AP_LIST_POSIXSEM_SERIALIZE ", 'posixsem'"
#else
# define AP_LIST_POSIXSEM_SERIALIZE
#endif
#if APR_HAS_PROC_PTHREAD_SERIALIZE
# define AP_LIST_PTHREAD_SERIALIZE ", 'pthread'"
#else
# define AP_LIST_PTHREAD_SERIALIZE
#endif
#if APR_HAS_FLOCK_SERIALIZE || APR_HAS_FCNTL_SERIALIZE
# define AP_LIST_FILE_SERIALIZE ", 'file:/path/to/file'"
#else
# define AP_LIST_FILE_SERIALIZE
#endif
#if APR_HAS_SYSVSEM_SERIALIZE || APR_HAS_POSIXSEM_SERIALIZE
# define AP_LIST_SEM_SERIALIZE ", 'sem'"
#else
# define AP_LIST_SEM_SERIALIZE
#endif

#define AP_ALL_AVAILABLE_MUTEXES_STRING                  \
    "Mutex mechanisms are: 'none', 'default'"            \
    AP_LIST_FLOCK_SERIALIZE   AP_LIST_FCNTL_SERIALIZE    \
    AP_LIST_FILE_SERIALIZE    AP_LIST_PTHREAD_SERIALIZE  \
    AP_LIST_SYSVSEM_SERIALIZE AP_LIST_POSIXSEM_SERIALIZE \
    AP_LIST_SEM_SERIALIZE

#define AP_AVAILABLE_MUTEXES_STRING                      \
    "Mutex mechanisms are: 'default'"                    \
    AP_LIST_FLOCK_SERIALIZE   AP_LIST_FCNTL_SERIALIZE    \
    AP_LIST_FILE_SERIALIZE    AP_LIST_PTHREAD_SERIALIZE  \
    AP_LIST_SYSVSEM_SERIALIZE AP_LIST_POSIXSEM_SERIALIZE \
    AP_LIST_SEM_SERIALIZE

#ifdef __cplusplus
extern "C" {
#endif

/**
 * Get Mutex config data and parse it
 * @param arg The mutex config string
 * @param pool The allocation pool
 * @param mutexmech The APR mutex locking mechanism
 * @param mutexfile The lockfile to use as required
 * @return APR status code
 * @fn apr_status_t ap_parse_mutex(const char *arg, apr_pool_t *pool,
                                        apr_lockmech_e *mutexmech,
                                        const char **mutexfile)
 */
AP_DECLARE(apr_status_t) ap_parse_mutex(const char *arg, apr_pool_t *pool,
                                        apr_lockmech_e *mutexmech,
                                        const char **mutexfile);

/* private function to process the Mutex directive */
AP_DECLARE_NONSTD(const char *) ap_set_mutex(cmd_parms *cmd, void *dummy,
                                             const char *arg);

/* private function to initialize Mutex infrastructure */
AP_DECLARE_NONSTD(void) ap_mutex_init(apr_pool_t *p);

/**
 * option flags for ap_mutex_register(), ap_global_mutex_create(), and
 * ap_proc_mutex_create()
 */
#define AP_MUTEX_ALLOW_NONE    1 /* allow "none" as mutex implementation;
                                  * respected only on ap_mutex_register()
                                  */
#define AP_MUTEX_DEFAULT_NONE  2 /* default to "none" for this mutex;
                                  * respected only on ap_mutex_register()
                                  */

/**
 * Register a module's mutex type with core to allow configuration
 * with the Mutex directive.  This must be called in the pre_config
 * hook; otherwise, configuration directives referencing this mutex
 * type will be rejected.
 *
 * The default_dir and default_mech parameters allow a module to set
 * defaults for the lock file directory and mechanism.  These could
 * be based on compile-time settings.  These aren't required except
 * in special circumstances.
 *
 * The order of precedence for the choice of mechanism and lock file
 * directory is:
 *
 *   1. Mutex directive specifically for this mutex
 *      e.g., Mutex mpm-default flock:/tmp/mpmlocks
 *   2. Mutex directive for global default
 *      e.g., Mutex default flock:/tmp/httpdlocks
 *   3. Defaults for this mutex provided on the ap_mutex_register()
 *   4. Built-in defaults for all mutexes, which are
 *      APR_LOCK_DEFAULT and DEFAULT_REL_RUNTIMEDIR.
 *
 * @param pconf The pconf pool
 * @param type The type name of the mutex, used as the basename of the
 * file associated with the mutex, if any.  This must be unique among
 * all mutex types (mutex creation accommodates multi-instance mutex
 * types); mod_foo might have mutex  types "foo-pipe" and "foo-shm"
 * @param default_dir Default dir for any lock file required for this
 * lock, to override built-in defaults; should be NULL for most
 * modules, to respect built-in defaults
 * @param default_mech Default mechanism for this lock, to override
 * built-in defaults; should be APR_LOCK_DEFAULT for most modules, to
 * respect built-in defaults
 * or NULL if there are no defaults for this mutex.
 * @param options combination of AP_MUTEX_* constants, or 0 for defaults
 */
AP_DECLARE(apr_status_t) ap_mutex_register(apr_pool_t *pconf,
                                           const char *type,
                                           const char *default_dir,
                                           apr_lockmech_e default_mech,
                                           apr_int32_t options);

/**
 * Create an APR global mutex that has been registered previously with
 * ap_mutex_register().  Mutex files, permissions, and error logging will
 * be handled internally.
 * @param mutex The memory address where the newly created mutex will be
 * stored.  If this mutex is disabled, mutex will be set to NULL on
 * output.  (That is allowed only if the AP_MUTEX_ALLOW_NONE flag is
 * passed to ap_mutex_register().)
 * @param name The generated filename of the created mutex, or NULL if
 * no file was created.  Pass NULL if this result is not needed.
 * @param type The type name of the mutex, matching the type name passed
 * to ap_mutex_register().
 * @param instance_id A unique string to be used in the lock filename IFF
 * this mutex type is multi-instance, NULL otherwise.
 * @param server server_rec of main server
 * @param pool pool lifetime of the mutex
 * @param options combination of AP_MUTEX_* constants, or 0 for defaults
 * (currently none are defined for this function)
 */
AP_DECLARE(apr_status_t) ap_global_mutex_create(apr_global_mutex_t **mutex,
                                                const char **name,
                                                const char *type,
                                                const char *instance_id,
                                                server_rec *server,
                                                apr_pool_t *pool,
                                                apr_int32_t options);

/**
 * Create an APR proc mutex that has been registered previously with
 * ap_mutex_register().  Mutex files, permissions, and error logging will
 * be handled internally.
 * @param mutex The memory address where the newly created mutex will be
 * stored.  If this mutex is disabled, mutex will be set to NULL on
 * output.  (That is allowed only if the AP_MUTEX_ALLOW_NONE flag is
 * passed to ap_mutex_register().)
 * @param name The generated filename of the created mutex, or NULL if
 * no file was created.  Pass NULL if this result is not needed.
 * @param type The type name of the mutex, matching the type name passed
 * to ap_mutex_register().
 * @param instance_id A unique string to be used in the lock filename IFF
 * this mutex type is multi-instance, NULL otherwise.
 * @param server server_rec of main server
 * @param pool pool lifetime of the mutex
 * @param options combination of AP_MUTEX_* constants, or 0 for defaults
 * (currently none are defined for this function)
 */
AP_DECLARE(apr_status_t) ap_proc_mutex_create(apr_proc_mutex_t **mutex,
                                              const char **name,
                                              const char *type,
                                              const char *instance_id,
                                              server_rec *server,
                                              apr_pool_t *pool,
                                              apr_int32_t options);

AP_CORE_DECLARE(void) ap_dump_mutexes(apr_pool_t *p, server_rec *s, apr_file_t *out);

#ifdef __cplusplus
}
#endif

#endif /* UTIL_MUTEX_H */
/** @} */