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/ScopedRWLock.h"
39 #include "private/bionic_futex.h"
40 #include "private/bionic_tls.h"
41
42 static pthread_internal_t* g_thread_list = nullptr;
43 static pthread_rwlock_t g_thread_list_lock = PTHREAD_RWLOCK_INITIALIZER;
44
__pthread_internal_add(pthread_internal_t * thread)45 pthread_t __pthread_internal_add(pthread_internal_t* thread) {
46 ScopedWriteLock locker(&g_thread_list_lock);
47
48 // We insert at the head.
49 thread->next = g_thread_list;
50 thread->prev = nullptr;
51 if (thread->next != nullptr) {
52 thread->next->prev = thread;
53 }
54 g_thread_list = thread;
55 return reinterpret_cast<pthread_t>(thread);
56 }
57
__pthread_internal_remove(pthread_internal_t * thread)58 void __pthread_internal_remove(pthread_internal_t* thread) {
59 ScopedWriteLock locker(&g_thread_list_lock);
60
61 if (thread->next != nullptr) {
62 thread->next->prev = thread->prev;
63 }
64 if (thread->prev != nullptr) {
65 thread->prev->next = thread->next;
66 } else {
67 g_thread_list = thread->next;
68 }
69 }
70
__pthread_internal_free(pthread_internal_t * thread)71 static void __pthread_internal_free(pthread_internal_t* thread) {
72 if (thread->mmap_size != 0) {
73 // Free mapped space, including thread stack and pthread_internal_t.
74 munmap(thread->mmap_base, thread->mmap_size);
75 }
76 }
77
__pthread_internal_remove_and_free(pthread_internal_t * thread)78 void __pthread_internal_remove_and_free(pthread_internal_t* thread) {
79 __pthread_internal_remove(thread);
80 __pthread_internal_free(thread);
81 }
82
__pthread_internal_gettid(pthread_t thread_id,const char * caller)83 pid_t __pthread_internal_gettid(pthread_t thread_id, const char* caller) {
84 pthread_internal_t* thread = __pthread_internal_find(thread_id, caller);
85 return thread ? thread->tid : -1;
86 }
87
__pthread_internal_find(pthread_t thread_id,const char * caller)88 pthread_internal_t* __pthread_internal_find(pthread_t thread_id, const char* caller) {
89 pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(thread_id);
90
91 // Check if we're looking for ourselves before acquiring the lock.
92 if (thread == __get_thread()) return thread;
93
94 {
95 // Make sure to release the lock before the abort below. Otherwise,
96 // some apps might deadlock in their own crash handlers (see b/6565627).
97 ScopedReadLock locker(&g_thread_list_lock);
98 for (pthread_internal_t* t = g_thread_list; t != nullptr; t = t->next) {
99 if (t == thread) return thread;
100 }
101 }
102
103 // Historically we'd return null, but
104 if (android_get_application_target_sdk_version() >= __ANDROID_API_O__) {
105 if (thread == nullptr) {
106 // This seems to be a common mistake, and it's relatively harmless because
107 // there will never be a valid thread at address 0, whereas other invalid
108 // addresses might sometimes contain threads or things that look enough like
109 // threads for us to do some real damage by continuing.
110 // TODO: try getting rid of this when Treble lets us keep vendor blobs on an old API level.
111 async_safe_format_log(ANDROID_LOG_WARN, "libc", "invalid pthread_t (0) passed to %s", caller);
112 } else {
113 async_safe_fatal("invalid pthread_t %p passed to %s", thread, caller);
114 }
115 }
116 return nullptr;
117 }
118