thr_detach.c revision 117907 
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_detach.c 117907 2003-07-23 02:11:07Z deischen $
33 */
34#include <sys/types.h>
35#include <machine/atomic.h>
36#include <errno.h>
37#include <pthread.h>
38#include "thr_private.h"
39
40__weak_reference(_pthread_detach, pthread_detach);
41
42int
43_pthread_detach(pthread_t pthread)
44{
45	struct pthread *curthread = _get_curthread();
46	struct kse_mailbox *kmbx = NULL;
47	struct pthread *joiner;
48	int rval = 0;
49
50	/* Check for invalid calling parameters: */
51	if (pthread == NULL || pthread->magic != THR_MAGIC)
52		/* Return an invalid argument error: */
53		rval = EINVAL;
54
55	else if ((rval = _thr_ref_add(curthread, pthread,
56	    /*include dead*/1)) != 0) {
57		/* Return an error: */
58	}
59
60	/* Check if the thread is already detached: */
61	else if ((pthread->attr.flags & PTHREAD_DETACHED) != 0) {
62		/* Return an error: */
63		_thr_ref_delete(curthread, pthread);
64		rval = EINVAL;
65	} else {
66		/* Lock the detached thread: */
67		THR_SCHED_LOCK(curthread, pthread);
68
69		/* Flag the thread as detached: */
70		pthread->attr.flags |= PTHREAD_DETACHED;
71
72		/* Retrieve any joining thread and remove it: */
73		joiner = pthread->joiner;
74		if ((joiner != NULL) && (joiner->kseg == pthread->kseg)) {
75			/*
76			 * We already own the scheduler lock for the joiner.
77			 * Take advantage of that and make the joiner runnable.
78			 */
79			if (joiner->join_status.thread == pthread) {
80				/*
81				 * Set the return value for the woken thread:
82				 */
83				joiner->join_status.error = ESRCH;
84				joiner->join_status.ret = NULL;
85				joiner->join_status.thread = NULL;
86
87				kmbx = _thr_setrunnable_unlocked(joiner);
88			}
89			joiner = NULL;
90		}
91		THR_SCHED_UNLOCK(curthread, pthread);
92		/* See if there is a thread waiting in pthread_join(): */
93		if ((joiner != NULL) &&
94		    (_thr_ref_add(curthread, joiner, 0) == 0)) {
95			/* Lock the joiner before fiddling with it. */
96			THR_SCHED_LOCK(curthread, joiner);
97			if (joiner->join_status.thread == pthread) {
98				/*
99				 * Set the return value for the woken thread:
100				 */
101				joiner->join_status.error = ESRCH;
102				joiner->join_status.ret = NULL;
103				joiner->join_status.thread = NULL;
104
105				kmbx = _thr_setrunnable_unlocked(joiner);
106			}
107			THR_SCHED_UNLOCK(curthread, joiner);
108			_thr_ref_delete(curthread, joiner);
109		}
110		_thr_ref_delete(curthread, pthread);
111		if (kmbx != NULL)
112			kse_wakeup(kmbx);
113	}
114
115	/* Return the completion status: */
116	return (rval);
117}
118