/* * Copyright (c) 1995 John Birrell . * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by John Birrell. * 4. Neither the name of the author nor the names of any co-contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $FreeBSD$ */ #include #include #include "thr_private.h" __weak_reference(_pthread_join, pthread_join); int _pthread_join(pthread_t pthread, void **thread_return) { int ret = 0; pthread_t thread; _thread_enter_cancellation_point(); /* Check if the caller has specified an invalid thread: */ if (pthread == NULL || pthread->magic != PTHREAD_MAGIC) { /* Invalid thread: */ _thread_leave_cancellation_point(); return(EINVAL); } /* Check if the caller has specified itself: */ if (pthread == curthread) { /* Avoid a deadlock condition: */ _thread_leave_cancellation_point(); return(EDEADLK); } /* * Lock the garbage collector mutex to ensure that the garbage * collector is not using the dead thread list. */ if (pthread_mutex_lock(&_gc_mutex) != 0) PANIC("Cannot lock gc mutex"); GIANT_LOCK(curthread); /* * Search for the specified thread in the list of active threads. This * is done manually here rather than calling _find_thread() because * the searches in _thread_list and _dead_list (as well as setting up * join/detach state) have to be done atomically. */ TAILQ_FOREACH(thread, &_thread_list, tle) if (thread == pthread) break; if (thread == NULL) /* * Search for the specified thread in the list of dead threads: */ TAILQ_FOREACH(thread, &_dead_list, dle) if (thread == pthread) break; /* Check if the thread was not found or has been detached: */ if (thread == NULL || ((pthread->attr.flags & PTHREAD_DETACHED) != 0)) { if (pthread_mutex_unlock(&_gc_mutex) != 0) PANIC("Cannot lock gc mutex"); ret = ESRCH; goto out; } if (pthread->joiner != NULL) { /* Multiple joiners are not supported. */ /* XXXTHR - support multiple joiners. */ if (pthread_mutex_unlock(&_gc_mutex) != 0) PANIC("Cannot lock gc mutex"); ret = ENOTSUP; goto out; /* Check if the thread is not dead: */ } /* * Unlock the garbage collector mutex, now that the garbage collector * can't be run: */ if (pthread_mutex_unlock(&_gc_mutex) != 0) PANIC("Cannot lock gc mutex"); if (pthread->state != PS_DEAD) { /* Set the running thread to be the joiner: */ pthread->joiner = curthread; /* Keep track of which thread we're joining to: */ curthread->join_status.thread = pthread; while (curthread->join_status.thread == pthread) { PTHREAD_SET_STATE(curthread, PS_JOIN); /* Wait for our signal to wake up. */ GIANT_UNLOCK(curthread); _thread_suspend(curthread, NULL); GIANT_LOCK(curthread); } /* * The thread return value and error are set by the thread we're * joining to when it exits or detaches: */ ret = curthread->join_status.error; if ((ret == 0) && (thread_return != NULL)) *thread_return = curthread->join_status.ret; } else { /* * The thread exited (is dead) without being detached, and no * thread has joined it. */ /* Check if the return value is required: */ if (thread_return != NULL) { /* Return the thread's return value: */ *thread_return = pthread->ret; } /* Make the thread collectable by the garbage collector. */ pthread->attr.flags |= PTHREAD_DETACHED; } out: GIANT_UNLOCK(curthread); _thread_leave_cancellation_point(); /* Return the completion status: */ return (ret); }