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 <errno.h>
30
31 #include "private/bionic_defs.h"
32 #include "private/bionic_futex.h"
33 #include "private/bionic_systrace.h"
34 #include "pthread_internal.h"
35
36 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
pthread_join(pthread_t t,void ** return_value)37 int pthread_join(pthread_t t, void** return_value) {
38 ScopedTrace trace("pthread_join");
39 if (t == pthread_self()) {
40 return EDEADLK;
41 }
42
43 pthread_internal_t* thread = __pthread_internal_find(t, "pthread_join");
44 if (thread == nullptr) {
45 return ESRCH;
46 }
47
48 ThreadJoinState old_state = THREAD_NOT_JOINED;
49 while ((old_state == THREAD_NOT_JOINED || old_state == THREAD_EXITED_NOT_JOINED) &&
50 !atomic_compare_exchange_weak(&thread->join_state, &old_state, THREAD_JOINED)) {
51 }
52
53 if (old_state == THREAD_DETACHED || old_state == THREAD_JOINED) {
54 return EINVAL;
55 }
56
57 pid_t tid = thread->tid;
58 volatile int* tid_ptr = &thread->tid;
59
60 // We set thread->join_state to THREAD_JOINED with atomic operation,
61 // so no one is going to remove this thread except us.
62
63 // Wait for the thread to actually exit, if it hasn't already.
64 while (*tid_ptr != 0) {
65 __futex_wait(tid_ptr, tid, nullptr);
66 }
67
68 if (return_value) {
69 *return_value = thread->return_value;
70 }
71
72 __pthread_internal_remove_and_free(thread);
73 return 0;
74 }
75