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_internal.h" 30 31#include <errno.h> 32#include <stdlib.h> 33#include <string.h> 34#include <sys/mman.h> 35 36#include <async_safe/log.h> 37 38#include "private/bionic_futex.h" 39#include "private/bionic_sdk_version.h" 40#include "private/bionic_tls.h" 41 42static pthread_internal_t* g_thread_list = nullptr; 43static pthread_rwlock_t g_thread_list_lock = PTHREAD_RWLOCK_INITIALIZER; 44 45template <bool write> class ScopedRWLock { 46 public: 47 ScopedRWLock(pthread_rwlock_t* rwlock) : rwlock_(rwlock) { 48 (write ? pthread_rwlock_wrlock : pthread_rwlock_rdlock)(rwlock_); 49 } 50 51 ~ScopedRWLock() { 52 pthread_rwlock_unlock(rwlock_); 53 } 54 55 private: 56 pthread_rwlock_t* rwlock_; 57 DISALLOW_IMPLICIT_CONSTRUCTORS(ScopedRWLock); 58}; 59 60typedef ScopedRWLock<true> ScopedWriteLock; 61typedef ScopedRWLock<false> ScopedReadLock; 62 63pthread_t __pthread_internal_add(pthread_internal_t* thread) { 64 ScopedWriteLock locker(&g_thread_list_lock); 65 66 // We insert at the head. 67 thread->next = g_thread_list; 68 thread->prev = nullptr; 69 if (thread->next != nullptr) { 70 thread->next->prev = thread; 71 } 72 g_thread_list = thread; 73 return reinterpret_cast<pthread_t>(thread); 74} 75 76void __pthread_internal_remove(pthread_internal_t* thread) { 77 ScopedWriteLock locker(&g_thread_list_lock); 78 79 if (thread->next != nullptr) { 80 thread->next->prev = thread->prev; 81 } 82 if (thread->prev != nullptr) { 83 thread->prev->next = thread->next; 84 } else { 85 g_thread_list = thread->next; 86 } 87} 88 89static void __pthread_internal_free(pthread_internal_t* thread) { 90 if (thread->mmap_size != 0) { 91 // Free mapped space, including thread stack and pthread_internal_t. 92 munmap(thread->attr.stack_base, thread->mmap_size); 93 } 94} 95 96void __pthread_internal_remove_and_free(pthread_internal_t* thread) { 97 __pthread_internal_remove(thread); 98 __pthread_internal_free(thread); 99} 100 101pthread_internal_t* __pthread_internal_find(pthread_t thread_id) { 102 pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(thread_id); 103 104 // Check if we're looking for ourselves before acquiring the lock. 105 if (thread == __get_thread()) return thread; 106 107 { 108 // Make sure to release the lock before the abort below. Otherwise, 109 // some apps might deadlock in their own crash handlers (see b/6565627). 110 ScopedReadLock locker(&g_thread_list_lock); 111 for (pthread_internal_t* t = g_thread_list; t != nullptr; t = t->next) { 112 if (t == thread) return thread; 113 } 114 } 115 116 // Historically we'd return null, but 117 if (bionic_get_application_target_sdk_version() >= __ANDROID_API_O__) { 118 if (thread == nullptr) { 119 // This seems to be a common mistake, and it's relatively harmless because 120 // there will never be a valid thread at address 0, whereas other invalid 121 // addresses might sometimes contain threads or things that look enough like 122 // threads for us to do some real damage by continuing. 123 // TODO: try getting rid of this when Treble lets us keep vendor blobs on an old API level. 124 async_safe_format_log(ANDROID_LOG_WARN, "libc", "invalid pthread_t (0) passed to libc"); 125 } else { 126 async_safe_fatal("invalid pthread_t %p passed to libc", thread); 127 } 128 } 129 return nullptr; 130} 131