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