This file is indexed.

/usr/include/apr-1.0/apr_global_mutex.h is in libapr1-dev 1.5.0-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  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
/* 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.
 */

#ifndef APR_GLOBAL_MUTEX_H
#define APR_GLOBAL_MUTEX_H

/**
 * @file apr_global_mutex.h
 * @brief APR Global Locking Routines
 */

#include "apr.h"
#include "apr_proc_mutex.h"    /* only for apr_lockmech_e */
#include "apr_pools.h"
#include "apr_errno.h"
#if APR_PROC_MUTEX_IS_GLOBAL
#include "apr_proc_mutex.h"
#endif

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */

/**
 * @defgroup APR_GlobalMutex Global Locking Routines
 * @ingroup APR 
 * @{
 */

#if !APR_PROC_MUTEX_IS_GLOBAL || defined(DOXYGEN)

/** Opaque global mutex structure. */
typedef struct apr_global_mutex_t apr_global_mutex_t;

/*   Function definitions */

/**
 * Create and initialize a mutex that can be used to synchronize both
 * processes and threads. Note: There is considerable overhead in using
 * this API if only cross-process or cross-thread mutual exclusion is
 * required. See apr_proc_mutex.h and apr_thread_mutex.h for more
 * specialized lock routines.
 * @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.
 * @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_global_mutex_create(apr_global_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_global_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_global_mutex_child_init(
                              apr_global_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_global_mutex_lock(apr_global_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_global_mutex_trylock(apr_global_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_global_mutex_unlock(apr_global_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_global_mutex_destroy(apr_global_mutex_t *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_global_mutex_lockfile(apr_global_mutex_t *mutex);

/**
 * Display the name of the mutex, as it relates to the actual method used
 * for the underlying apr_proc_mutex_t, if any.  NULL is returned if
 * there is no underlying apr_proc_mutex_t.
 * @param mutex the name of the mutex
 */
APR_DECLARE(const char *) apr_global_mutex_name(apr_global_mutex_t *mutex);

/**
 * Get the pool used by this global_mutex.
 * @return apr_pool_t the pool
 */
APR_POOL_DECLARE_ACCESSOR(global_mutex);

#else /* APR_PROC_MUTEX_IS_GLOBAL */

/* Some platforms [e.g. Win32] have cross process locks that are truly
 * global locks, since there isn't the concept of cross-process locks.
 * Define these platforms in terms of an apr_proc_mutex_t.
 */

#define apr_global_mutex_t          apr_proc_mutex_t
#define apr_global_mutex_create     apr_proc_mutex_create
#define apr_global_mutex_child_init apr_proc_mutex_child_init
#define apr_global_mutex_lock       apr_proc_mutex_lock
#define apr_global_mutex_trylock    apr_proc_mutex_trylock
#define apr_global_mutex_unlock     apr_proc_mutex_unlock
#define apr_global_mutex_destroy    apr_proc_mutex_destroy
#define apr_global_mutex_lockfile   apr_proc_mutex_lockfile
#define apr_global_mutex_name       apr_proc_mutex_name
#define apr_global_mutex_pool_get   apr_proc_mutex_pool_get

#endif

/** @} */

#ifdef __cplusplus
}
#endif

#endif  /* ndef APR_GLOBAL_MUTEX_H */