thr_join.c revision 54708 
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 54708 1999-12-17 00:57:54Z 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	pthread_t pthread1 = NULL;
44
45	_thread_enter_cancellation_point();
46
47	/* Check if the caller has specified an invalid thread: */
48	if (pthread == NULL || pthread->magic != PTHREAD_MAGIC) {
49		/* Invalid thread: */
50		_thread_leave_cancellation_point();
51		return(EINVAL);
52	}
53
54	/* Check if the caller has specified itself: */
55	if (pthread == _thread_run) {
56		/* Avoid a deadlock condition: */
57		_thread_leave_cancellation_point();
58		return(EDEADLK);
59	}
60
61	/*
62	 * Find the thread in the list of active threads or in the
63	 * list of dead threads:
64	 */
65	if (_find_thread(pthread) == 0 ||
66	    _find_dead_thread(pthread) == 0)
67		pthread1  = pthread;
68
69	if (pthread1 == NULL)
70		/* Return an error: */
71		ret = ESRCH;
72
73	/* Check if this thread has been detached: */
74	else if ((pthread->attr.flags & PTHREAD_DETACHED) != 0)
75		/* Return an error: */
76		ret = ESRCH;
77
78	/* Check if the thread is not dead: */
79	else if (pthread->state != PS_DEAD) {
80		/* Clear the interrupted flag: */
81		_thread_run->interrupted = 0;
82
83		/*
84		 * Protect against being context switched out while
85		 * adding this thread to the join queue.
86		 */
87		_thread_kern_sig_defer();
88
89		/* Add the running thread to the join queue: */
90		TAILQ_INSERT_TAIL(&(pthread->join_queue), _thread_run, qe);
91
92		/* Schedule the next thread: */
93		_thread_kern_sched_state(PS_JOIN, __FILE__, __LINE__);
94
95		if (_thread_run->interrupted != 0)
96			TAILQ_REMOVE(&(pthread->join_queue), _thread_run, qe);
97
98		_thread_kern_sig_undefer();
99
100		if ((_thread_run->cancelflags & PTHREAD_CANCEL_NEEDED) != 0) {
101			_thread_run->cancelflags &= ~PTHREAD_CANCEL_NEEDED;
102			_thread_exit_cleanup();
103			pthread_exit(PTHREAD_CANCELED);
104		}
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#endif
128