thr_join.c revision 67097 
1/*
2 * Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
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 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by John Birrell.
16 * 4. Neither the name of the author nor the names of any co-contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * $FreeBSD: head/lib/libkse/thread/thr_join.c 67097 2000-10-13 22:12:32Z deischen $
33 */
34#include <errno.h>
35#ifdef _THREAD_SAFE
36#include <pthread.h>
37#include "pthread_private.h"
38
39int
40pthread_join(pthread_t pthread, void **thread_return)
41{
42	int ret = 0;
43
44	_thread_enter_cancellation_point();
45
46	/* Check if the caller has specified an invalid thread: */
47	if (pthread == NULL || pthread->magic != PTHREAD_MAGIC) {
48		/* Invalid thread: */
49		_thread_leave_cancellation_point();
50		return(EINVAL);
51	}
52
53	/* Check if the caller has specified itself: */
54	if (pthread == _thread_run) {
55		/* Avoid a deadlock condition: */
56		_thread_leave_cancellation_point();
57		return(EDEADLK);
58	}
59
60	/*
61	 * Find the thread in the list of active threads or in the
62	 * list of dead threads:
63	 */
64	if ((_find_thread(pthread) != 0) && (_find_dead_thread(pthread) != 0))
65		/* Return an error: */
66		ret = ESRCH;
67
68	/* Check if this thread has been detached: */
69	else if ((pthread->attr.flags & PTHREAD_DETACHED) != 0)
70		/* Return an error: */
71		ret = ESRCH;
72
73	/* Check if the thread is not dead: */
74	else if (pthread->state != PS_DEAD) {
75		PTHREAD_ASSERT_NOT_IN_SYNCQ(_thread_run);
76
77		/* Clear the interrupted flag: */
78		_thread_run->interrupted = 0;
79
80		/*
81		 * Protect against being context switched out while
82		 * adding this thread to the join queue.
83		 */
84		_thread_kern_sig_defer();
85
86		/* Add the running thread to the join queue: */
87		TAILQ_INSERT_TAIL(&(pthread->join_queue), _thread_run, sqe);
88		_thread_run->flags |= PTHREAD_FLAGS_IN_JOINQ;
89		_thread_run->data.thread = pthread;
90
91		/* Schedule the next thread: */
92		_thread_kern_sched_state(PS_JOIN, __FILE__, __LINE__);
93
94		if (_thread_run->interrupted != 0) {
95			TAILQ_REMOVE(&(pthread->join_queue), _thread_run, sqe);
96			_thread_run->flags &= ~PTHREAD_FLAGS_IN_JOINQ;
97		}
98		_thread_run->data.thread = NULL;
99
100		_thread_kern_sig_undefer();
101
102		if (_thread_run->interrupted != 0 &&
103		    _thread_run->continuation != NULL)
104			_thread_run->continuation(_thread_run);
105
106		/* Check if the thread is not detached: */
107		if ((pthread->attr.flags & PTHREAD_DETACHED) == 0) {
108			/* Check if the return value is required: */
109			if (thread_return)
110				/* Return the thread's return value: */
111				*thread_return = pthread->ret;
112		}
113		else
114			/* Return an error: */
115			ret = ESRCH;
116
117	/* Check if the return value is required: */
118	} else if (thread_return != NULL)
119		/* Return the thread's return value: */
120		*thread_return = pthread->ret;
121
122	_thread_leave_cancellation_point();
123
124	/* Return the completion status: */
125	return (ret);
126}
127
128void
129_join_backout(pthread_t pthread)
130{
131	_thread_kern_sig_defer();
132	if (pthread->state == PS_JOIN) {
133		TAILQ_REMOVE(&pthread->data.thread->join_queue, pthread, sqe);
134		_thread_run->flags &= ~PTHREAD_FLAGS_IN_JOINQ;
135	}
136	_thread_kern_sig_undefer();
137}
138#endif
139