| /* |
| * 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> |
| |
| #include"platform/bionic/macros.h" |
| |
| structatfork_t{ |
| atfork_t* next; |
| atfork_t* prev; |
| |
| void(*prepare)(void); |
| void(*child)(void); |
| void(*parent)(void); |
| |
| void* dso_handle; |
| }; |
| |
| classatfork_list_t{ |
| public: |
| constexpratfork_list_t(): first_(nullptr), last_(nullptr){} |
| |
| template<typename F> |
| void walk_forward(F f){ |
| for(atfork_t* it= first_; it!=nullptr; it= it->next){ |
| f(it); |
| } |
| } |
| |
| template<typename F> |
| void walk_backwards(F f){ |
| for(atfork_t* it= last_; it!=nullptr; it= it->prev){ |
| f(it); |
| } |
| } |
| |
| void push_back(atfork_t* entry){ |
| entry->next=nullptr; |
| entry->prev= last_; |
| if(entry->prev!=nullptr){ |
| entry->prev->next= entry; |
| } |
| if(first_==nullptr){ |
| first_= entry; |
| } |
| last_= entry; |
| } |
| |
| template<typename F> |
| void remove_if(F predicate){ |
| atfork_t* it= first_; |
| while(it!=nullptr){ |
| if(predicate(it)){ |
| atfork_t* entry= it; |
| it= it->next; |
| remove(entry); |
| }else{ |
| it= it->next; |
| } |
| } |
| } |
| |
| private: |
| void remove(atfork_t* entry){ |
| if(entry->prev!=nullptr){ |
| entry->prev->next= entry->next; |
| }else{ |
| first_= entry->next; |
| } |
| |
| if(entry->next!=nullptr){ |
| entry->next->prev= entry->prev; |
| }else{ |
| last_= entry->prev; |
| } |
| |
| free(entry); |
| } |
| |
| atfork_t* first_; |
| atfork_t* last_; |
| |
| BIONIC_DISALLOW_COPY_AND_ASSIGN(atfork_list_t); |
| }; |
| |
| staticpthread_mutex_t g_atfork_list_mutex= PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP; |
| staticatfork_list_t g_atfork_list; |
| |
| 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. |
| 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. |
| g_atfork_list.walk_backwards([](atfork_t* it){ |
| if(it->prepare!=nullptr){ |
| it->prepare(); |
| } |
| }); |
| } |
| |
| void __bionic_atfork_run_child(){ |
| g_atfork_list_mutex= PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP; |
| |
| pthread_mutex_lock(&g_atfork_list_mutex); |
| g_atfork_list.walk_forward([](atfork_t* it){ |
| if(it->child!=nullptr){ |
| it->child(); |
| } |
| }); |
| pthread_mutex_unlock(&g_atfork_list_mutex); |
| } |
| |
| void __bionic_atfork_run_parent(){ |
| g_atfork_list.walk_forward([](atfork_t* it){ |
| if(it->parent!=nullptr){ |
| it->parent(); |
| } |
| }); |
| |
| pthread_mutex_unlock(&g_atfork_list_mutex); |
| } |
| |
| // __register_atfork is the name used by glibc |
| extern"C"int __register_atfork(void(*prepare)(void),void(*parent)(void), |
| void(*child)(void),void* dso){ |
| atfork_t* entry=reinterpret_cast<atfork_t*>(malloc(sizeof(atfork_t))); |
| if(entry==nullptr){ |
| return ENOMEM; |
| } |
| |
| entry->prepare= prepare; |
| entry->parent= parent; |
| entry->child= child; |
| entry->dso_handle= dso; |
| |
| pthread_mutex_lock(&g_atfork_list_mutex); |
| |
| g_atfork_list.push_back(entry); |
| |
| pthread_mutex_unlock(&g_atfork_list_mutex); |
| |
| return0; |
| } |
| |
| extern"C" __LIBC_HIDDEN__void __unregister_atfork(void* dso){ |
| pthread_mutex_lock(&g_atfork_list_mutex); |
| g_atfork_list.remove_if([&](constatfork_t* entry){ |
| return entry->dso_handle== dso; |
| }); |
| pthread_mutex_unlock(&g_atfork_list_mutex); |
| } |
