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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 <pthread.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include "private/bionic_constants.h"
#include "private/bionic_defs.h"
#include "private/ScopedSignalBlocker.h"
#include "pthread_internal.h"
extern "C" __noreturn void _exit_with_stack_teardown(void*, size_t);
extern "C" __noreturn void __exit(int);
extern "C" int __set_tid_address(int*);
extern "C" void __cxa_thread_finalize();
/* CAVEAT: our implementation of pthread_cleanup_push/pop doesn't support C++ exceptions
* and thread cancelation
*/
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
void __pthread_cleanup_push(__pthread_cleanup_t* c, __pthread_cleanup_func_t routine, void* arg) {
pthread_internal_t* thread = __get_thread();
c->__cleanup_routine = routine;
c->__cleanup_arg = arg;
c->__cleanup_prev = thread->cleanup_stack;
thread->cleanup_stack = c;
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
void __pthread_cleanup_pop(__pthread_cleanup_t* c, int execute) {
pthread_internal_t* thread = __get_thread();
thread->cleanup_stack = c->__cleanup_prev;
if (execute) {
c->__cleanup_routine(c->__cleanup_arg);
}
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
void pthread_exit(void* return_value) {
// Call dtors for thread_local objects first.
__cxa_thread_finalize();
pthread_internal_t* thread = __get_thread();
thread->return_value = return_value;
// Call the cleanup handlers.
while (thread->cleanup_stack) {
__pthread_cleanup_t* c = thread->cleanup_stack;
thread->cleanup_stack = c->__cleanup_prev;
c->__cleanup_routine(c->__cleanup_arg);
}
// Call the TLS destructors. It is important to do that before removing this
// thread from the global list. This will ensure that if someone else deletes
// a TLS key, the corresponding value will be set to NULL in this thread's TLS
// space (see pthread_key_delete).
pthread_key_clean_all();
if (thread->alternate_signal_stack != nullptr) {
// Tell the kernel to stop using the alternate signal stack.
stack_t ss;
memset(&ss, 0, sizeof(ss));
ss.ss_flags = SS_DISABLE;
sigaltstack(&ss, nullptr);
// Free it.
munmap(thread->alternate_signal_stack, SIGNAL_STACK_SIZE);
thread->alternate_signal_stack = nullptr;
}
ThreadJoinState old_state = THREAD_NOT_JOINED;
while (old_state == THREAD_NOT_JOINED &&
!atomic_compare_exchange_weak(&thread->join_state, &old_state, THREAD_EXITED_NOT_JOINED)) {
}
// We don't want to take a signal after unmapping the stack, the shadow call
// stack, or dynamic TLS memory.
ScopedSignalBlocker ssb;
#ifdef __aarch64__
// Free the shadow call stack and guard pages.
munmap(thread->shadow_call_stack_guard_region, SCS_GUARD_REGION_SIZE);
#endif
// Free the ELF TLS DTV and all dynamically-allocated ELF TLS memory.
__free_dynamic_tls(__get_bionic_tcb());
if (old_state == THREAD_DETACHED) {
// The thread is detached, no one will use pthread_internal_t after pthread_exit.
// So we can free mapped space, which includes pthread_internal_t and thread stack.
// First make sure that the kernel does not try to clear the tid field
// because we'll have freed the memory before the thread actually exits.
__set_tid_address(nullptr);
// pthread_internal_t is freed below with stack, not here.
__pthread_internal_remove(thread);
if (thread->mmap_size != 0) {
// We need to free mapped space for detached threads when they exit.
// That's not something we can do in C.
__hwasan_thread_exit();
_exit_with_stack_teardown(thread->mmap_base, thread->mmap_size);
}
}
// No need to free mapped space. Either there was no space mapped, or it is left for
// the pthread_join caller to clean up.
__hwasan_thread_exit();
__exit(0);
}
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