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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 <sys/mman.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*);
/* CAVEAT: our implementation of pthread_cleanup_push/pop doesn't support C++ exceptions
* and thread cancelation
*/
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;
}
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);
}
}
void pthread_exit(void* return_value) {
pthread_internal_t* thread = __get_thread();
thread->return_value = return_value;
// Call the cleanup handlers first.
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 != NULL) {
// Tell the kernel to stop using the alternate signal stack.
stack_t ss;
ss.ss_sp = NULL;
ss.ss_flags = SS_DISABLE;
sigaltstack(&ss, NULL);
// Free it.
munmap(thread->alternate_signal_stack, SIGSTKSZ);
thread->alternate_signal_stack = NULL;
}
// Keep track of what we need to know about the stack before we lose the pthread_internal_t.
void* stack_base = thread->attr.stack_base;
size_t stack_size = thread->attr.stack_size;
bool user_allocated_stack = thread->user_allocated_stack();
pthread_mutex_lock(&g_thread_list_lock);
if ((thread->attr.flags & PTHREAD_ATTR_FLAG_DETACHED) != 0) {
// The thread is detached, so we can free the pthread_internal_t.
// 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(NULL);
_pthread_internal_remove_locked(thread);
} else {
// Make sure that the pthread_internal_t doesn't have stale pointers to a stack that
// will be unmapped after the exit call below.
if (!user_allocated_stack) {
thread->attr.stack_base = NULL;
thread->attr.stack_size = 0;
thread->tls = NULL;
}
// pthread_join is responsible for destroying the pthread_internal_t for non-detached threads.
// The kernel will futex_wake on the pthread_internal_t::tid field to wake pthread_join.
}
pthread_mutex_unlock(&g_thread_list_lock);
// Perform a second key cleanup. When using jemalloc, a call to free from
// _pthread_internal_remove_locked causes the memory associated with a key
// to be reallocated.
// TODO: When b/16847284 is fixed this call can be removed.
pthread_key_clean_all();
if (user_allocated_stack) {
// Cleaning up this thread's stack is the creator's responsibility, not ours.
__exit(0);
} else {
// We need to munmap the stack we're running on before calling exit.
// That's not something we can do in C.
// We don't want to take a signal after we've unmapped the stack.
// That's one last thing we can handle in C.
sigset_t mask;
sigfillset(&mask);
sigprocmask(SIG_SETMASK, &mask, NULL);
_exit_with_stack_teardown(stack_base, stack_size);
}
}
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