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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <errno.h>
#include <pthread.h>
#include <stdlib.h>
struct atfork_t {
atfork_t* next;
atfork_t* prev;
void (*prepare)(void);
void (*child)(void);
void (*parent)(void);
};
struct atfork_list_t {
atfork_t* first;
atfork_t* last;
};
static pthread_mutex_t g_atfork_list_mutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
static atfork_list_t g_atfork_list = { NULL, NULL };
void __bionic_atfork_run_prepare() {
// We lock the atfork list here, unlock it in the parent, and reset it in the child.
// This ensures that nobody can modify the handler array between the calls
// to the prepare and parent/child handlers.
//
// TODO: If a handler tries to mutate the list, they'll block. We should probably copy
// the list before forking, and have prepare, parent, and child all work on the consistent copy.
pthread_mutex_lock(&g_atfork_list_mutex);
// Call pthread_atfork() prepare handlers. POSIX states that the prepare
// handlers should be called in the reverse order of the parent/child
// handlers, so we iterate backwards.
for (atfork_t* it = g_atfork_list.last; it != NULL; it = it->prev) {
if (it->prepare != NULL) {
it->prepare();
}
}
}
void __bionic_atfork_run_child() {
for (atfork_t* it = g_atfork_list.first; it != NULL; it = it->next) {
if (it->child != NULL) {
it->child();
}
}
g_atfork_list_mutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
}
void __bionic_atfork_run_parent() {
for (atfork_t* it = g_atfork_list.first; it != NULL; it = it->next) {
if (it->parent != NULL) {
it->parent();
}
}
pthread_mutex_unlock(&g_atfork_list_mutex);
}
int pthread_atfork(void (*prepare)(void), void (*parent)(void), void(*child)(void)) {
atfork_t* entry = reinterpret_cast<atfork_t*>(malloc(sizeof(atfork_t)));
if (entry == NULL) {
return ENOMEM;
}
entry->prepare = prepare;
entry->parent = parent;
entry->child = child;
pthread_mutex_lock(&g_atfork_list_mutex);
// Append 'entry' to the list.
entry->next = NULL;
entry->prev = g_atfork_list.last;
if (entry->prev != NULL) {
entry->prev->next = entry;
}
if (g_atfork_list.first == NULL) {
g_atfork_list.first = entry;
}
g_atfork_list.last = entry;
pthread_mutex_unlock(&g_atfork_list_mutex);
return 0;
}
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