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 <string.h> 34 #include <sys/mman.h> 35 36 #include "private/bionic_defs.h" 37 #include "private/ScopedSignalBlocker.h" 38 #include "pthread_internal.h" 39 40 extern "C" __noreturn void _exit_with_stack_teardown(void*, size_t); 41 extern "C" __noreturn void __exit(int); 42 extern "C" int __set_tid_address(int*); 43 extern "C" void __cxa_thread_finalize(); 44 45 /* CAVEAT: our implementation of pthread_cleanup_push/pop doesn't support C++ exceptions 46 * and thread cancelation 47 */ 48 49 __BIONIC_WEAK_FOR_NATIVE_BRIDGE 50 void __pthread_cleanup_push(__pthread_cleanup_t* c, __pthread_cleanup_func_t routine, void* arg) { 51 pthread_internal_t* thread = __get_thread(); 52 c->__cleanup_routine = routine; 53 c->__cleanup_arg = arg; 54 c->__cleanup_prev = thread->cleanup_stack; 55 thread->cleanup_stack = c; 56 } 57 58 __BIONIC_WEAK_FOR_NATIVE_BRIDGE 59 void __pthread_cleanup_pop(__pthread_cleanup_t* c, int execute) { 60 pthread_internal_t* thread = __get_thread(); 61 thread->cleanup_stack = c->__cleanup_prev; 62 if (execute) { 63 c->__cleanup_routine(c->__cleanup_arg); 64 } 65 } 66 67 static void __pthread_unmap_tls(pthread_internal_t* thread) { 68 // Unmap the bionic TLS, including guard pages. 69 void* allocation = reinterpret_cast<char*>(thread->bionic_tls) - PTHREAD_GUARD_SIZE; 70 munmap(allocation, BIONIC_TLS_SIZE + 2 * PTHREAD_GUARD_SIZE); 71 } 72 73 __BIONIC_WEAK_FOR_NATIVE_BRIDGE 74 void pthread_exit(void* return_value) { 75 // Call dtors for thread_local objects first. 76 __cxa_thread_finalize(); 77 78 pthread_internal_t* thread = __get_thread(); 79 thread->return_value = return_value; 80 81 // Call the cleanup handlers. 82 while (thread->cleanup_stack) { 83 __pthread_cleanup_t* c = thread->cleanup_stack; 84 thread->cleanup_stack = c->__cleanup_prev; 85 c->__cleanup_routine(c->__cleanup_arg); 86 } 87 88 // Call the TLS destructors. It is important to do that before removing this 89 // thread from the global list. This will ensure that if someone else deletes 90 // a TLS key, the corresponding value will be set to NULL in this thread's TLS 91 // space (see pthread_key_delete). 92 pthread_key_clean_all(); 93 94 if (thread->alternate_signal_stack != NULL) { 95 // Tell the kernel to stop using the alternate signal stack. 96 stack_t ss; 97 memset(&ss, 0, sizeof(ss)); 98 ss.ss_flags = SS_DISABLE; 99 sigaltstack(&ss, NULL); 100 101 // Free it. 102 munmap(thread->alternate_signal_stack, SIGNAL_STACK_SIZE); 103 thread->alternate_signal_stack = NULL; 104 } 105 106 ThreadJoinState old_state = THREAD_NOT_JOINED; 107 while (old_state == THREAD_NOT_JOINED && 108 !atomic_compare_exchange_weak(&thread->join_state, &old_state, THREAD_EXITED_NOT_JOINED)) { 109 } 110 111 if (old_state == THREAD_DETACHED) { 112 // The thread is detached, no one will use pthread_internal_t after pthread_exit. 113 // So we can free mapped space, which includes pthread_internal_t and thread stack. 114 // First make sure that the kernel does not try to clear the tid field 115 // because we'll have freed the memory before the thread actually exits. 116 __set_tid_address(NULL); 117 118 // pthread_internal_t is freed below with stack, not here. 119 __pthread_internal_remove(thread); 120 121 if (thread->mmap_size != 0) { 122 // We need to free mapped space for detached threads when they exit. 123 // That's not something we can do in C. 124 125 // We don't want to take a signal after we've unmapped the stack. 126 // That's one last thing we can do before dropping to assembler. 127 ScopedSignalBlocker ssb; 128 __pthread_unmap_tls(thread); 129 _exit_with_stack_teardown(thread->attr.stack_base, thread->mmap_size); 130 } 131 } 132 133 // No need to free mapped space. Either there was no space mapped, or it is left for 134 // the pthread_join caller to clean up. 135 __pthread_unmap_tls(thread); 136 __exit(0); 137 } 138
