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