134 lines
5 KiB
C++
134 lines
5 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 <pthread.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <sys/mman.h>
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#include "pthread_internal.h"
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extern "C" __noreturn void _exit_with_stack_teardown(void*, size_t);
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extern "C" __noreturn void __exit(int);
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extern "C" int __set_tid_address(int*);
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extern "C" void __set_tls(void*);
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/* CAVEAT: our implementation of pthread_cleanup_push/pop doesn't support C++ exceptions
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* and thread cancelation
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*/
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void __pthread_cleanup_push(__pthread_cleanup_t* c, __pthread_cleanup_func_t routine, void* arg) {
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pthread_internal_t* thread = __get_thread();
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c->__cleanup_routine = routine;
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c->__cleanup_arg = arg;
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c->__cleanup_prev = thread->cleanup_stack;
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thread->cleanup_stack = c;
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}
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void __pthread_cleanup_pop(__pthread_cleanup_t* c, int execute) {
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pthread_internal_t* thread = __get_thread();
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thread->cleanup_stack = c->__cleanup_prev;
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if (execute) {
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c->__cleanup_routine(c->__cleanup_arg);
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}
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}
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void pthread_exit(void* return_value) {
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pthread_internal_t* thread = __get_thread();
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thread->return_value = return_value;
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// Call the cleanup handlers first.
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while (thread->cleanup_stack) {
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__pthread_cleanup_t* c = thread->cleanup_stack;
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thread->cleanup_stack = c->__cleanup_prev;
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c->__cleanup_routine(c->__cleanup_arg);
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}
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// Call the TLS destructors. It is important to do that before removing this
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// thread from the global list. This will ensure that if someone else deletes
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// a TLS key, the corresponding value will be set to NULL in this thread's TLS
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// space (see pthread_key_delete).
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pthread_key_clean_all();
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// Clear tls to prevent further use of __get_tls(), see b/16847284.
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__set_tls(NULL);
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if (thread->alternate_signal_stack != NULL) {
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// Tell the kernel to stop using the alternate signal stack.
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stack_t ss;
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ss.ss_sp = NULL;
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ss.ss_flags = SS_DISABLE;
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sigaltstack(&ss, NULL);
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// Free it.
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munmap(thread->alternate_signal_stack, SIGSTKSZ);
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thread->alternate_signal_stack = NULL;
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}
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// Keep track of what we need to know about the stack before we lose the pthread_internal_t.
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void* stack_base = thread->attr.stack_base;
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size_t stack_size = thread->attr.stack_size;
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bool user_allocated_stack = thread->user_allocated_stack();
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pthread_mutex_lock(&g_thread_list_lock);
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if ((thread->attr.flags & PTHREAD_ATTR_FLAG_DETACHED) != 0) {
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// The thread is detached, so we can free the pthread_internal_t.
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// First make sure that the kernel does not try to clear the tid field
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// because we'll have freed the memory before the thread actually exits.
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__set_tid_address(NULL);
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_pthread_internal_remove_locked(thread);
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} else {
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// Make sure that the pthread_internal_t doesn't have stale pointers to a stack that
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// will be unmapped after the exit call below.
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if (!user_allocated_stack) {
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thread->attr.stack_base = NULL;
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thread->attr.stack_size = 0;
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thread->tls = NULL;
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}
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// pthread_join is responsible for destroying the pthread_internal_t for non-detached threads.
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// The kernel will futex_wake on the pthread_internal_t::tid field to wake pthread_join.
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}
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pthread_mutex_unlock(&g_thread_list_lock);
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if (user_allocated_stack) {
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// Cleaning up this thread's stack is the creator's responsibility, not ours.
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__exit(0);
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} else {
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// We need to munmap the stack we're running on before calling exit.
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// That's not something we can do in C.
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// We don't want to take a signal after we've unmapped the stack.
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// That's one last thing we can handle in C.
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sigset_t mask;
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sigfillset(&mask);
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sigprocmask(SIG_SETMASK, &mask, NULL);
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_exit_with_stack_teardown(stack_base, stack_size);
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}
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}
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