1/* 2 * Copyright (C) 2008 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29#include <pthread.h> 30 31#include <signal.h> 32#include <stdlib.h> 33#include <sys/mman.h> 34 35#include "pthread_internal.h" 36 37extern "C" __noreturn void _exit_with_stack_teardown(void*, size_t); 38extern "C" __noreturn void __exit(int); 39extern "C" int __set_tid_address(int*); 40extern "C" void __cxa_thread_finalize(); 41 42/* CAVEAT: our implementation of pthread_cleanup_push/pop doesn't support C++ exceptions 43 * and thread cancelation 44 */ 45 46void __pthread_cleanup_push(__pthread_cleanup_t* c, __pthread_cleanup_func_t routine, void* arg) { 47 pthread_internal_t* thread = __get_thread(); 48 c->__cleanup_routine = routine; 49 c->__cleanup_arg = arg; 50 c->__cleanup_prev = thread->cleanup_stack; 51 thread->cleanup_stack = c; 52} 53 54void __pthread_cleanup_pop(__pthread_cleanup_t* c, int execute) { 55 pthread_internal_t* thread = __get_thread(); 56 thread->cleanup_stack = c->__cleanup_prev; 57 if (execute) { 58 c->__cleanup_routine(c->__cleanup_arg); 59 } 60} 61 62void pthread_exit(void* return_value) { 63 // Call dtors for thread_local objects first. 64 __cxa_thread_finalize(); 65 66 pthread_internal_t* thread = __get_thread(); 67 thread->return_value = return_value; 68 69 // Call the cleanup handlers. 70 while (thread->cleanup_stack) { 71 __pthread_cleanup_t* c = thread->cleanup_stack; 72 thread->cleanup_stack = c->__cleanup_prev; 73 c->__cleanup_routine(c->__cleanup_arg); 74 } 75 76 // Call the TLS destructors. It is important to do that before removing this 77 // thread from the global list. This will ensure that if someone else deletes 78 // a TLS key, the corresponding value will be set to NULL in this thread's TLS 79 // space (see pthread_key_delete). 80 pthread_key_clean_all(); 81 82 if (thread->alternate_signal_stack != NULL) { 83 // Tell the kernel to stop using the alternate signal stack. 84 stack_t ss; 85 ss.ss_sp = NULL; 86 ss.ss_flags = SS_DISABLE; 87 sigaltstack(&ss, NULL); 88 89 // Free it. 90 munmap(thread->alternate_signal_stack, SIGNAL_STACK_SIZE); 91 thread->alternate_signal_stack = NULL; 92 } 93 94 ThreadJoinState old_state = THREAD_NOT_JOINED; 95 while (old_state == THREAD_NOT_JOINED && 96 !atomic_compare_exchange_weak(&thread->join_state, &old_state, THREAD_EXITED_NOT_JOINED)) { 97 } 98 99 if (old_state == THREAD_DETACHED) { 100 // The thread is detached, no one will use pthread_internal_t after pthread_exit. 101 // So we can free mapped space, which includes pthread_internal_t and thread stack. 102 // First make sure that the kernel does not try to clear the tid field 103 // because we'll have freed the memory before the thread actually exits. 104 __set_tid_address(NULL); 105 106 // pthread_internal_t is freed below with stack, not here. 107 __pthread_internal_remove(thread); 108 109 if (thread->mmap_size != 0) { 110 // We need to free mapped space for detached threads when they exit. 111 // That's not something we can do in C. 112 113 // We don't want to take a signal after we've unmapped the stack. 114 // That's one last thing we can handle in C. 115 sigset_t mask; 116 sigfillset(&mask); 117 sigprocmask(SIG_SETMASK, &mask, NULL); 118 119 _exit_with_stack_teardown(thread->attr.stack_base, thread->mmap_size); 120 } 121 } 122 123 // No need to free mapped space. Either there was no space mapped, or it is left for 124 // the pthread_join caller to clean up. 125 __exit(0); 126} 127