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