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