thr_join.c revision 153526 
1/*
2 * Copyright (c) 2005, David Xu <davidxu@freebsd.org>
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 unmodified, this list of conditions, and the following
10 *    disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 *
26 * $FreeBSD: head/lib/libthr/thread/thr_join.c 153526 2005-12-19 03:20:55Z davidxu $
27 *
28 */
29
30#include <errno.h>
31#include <pthread.h>
32
33#include "thr_private.h"
34
35static int join_common(pthread_t, void **, const struct timespec *);
36
37__weak_reference(_pthread_join, pthread_join);
38__weak_reference(_pthread_timedjoin_np, pthread_timedjoin_np);
39
40static void backout_join(void *arg)
41{
42	struct pthread *curthread = _get_curthread();
43	struct pthread *pthread = (struct pthread *)arg;
44
45	THREAD_LIST_LOCK(curthread);
46	pthread->joiner = NULL;
47	THREAD_LIST_UNLOCK(curthread);
48}
49
50int
51_pthread_join(pthread_t pthread, void **thread_return)
52{
53	return (join_common(pthread, thread_return, NULL));
54}
55
56int
57_pthread_timedjoin_np(pthread_t pthread, void **thread_return,
58	const struct timespec *abstime)
59{
60	if (abstime == NULL || abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
61	    abstime->tv_nsec >= 1000000000)
62		return (EINVAL);
63
64	return (join_common(pthread, thread_return, abstime));
65}
66
67static int
68join_common(pthread_t pthread, void **thread_return,
69	const struct timespec *abstime)
70{
71	struct pthread *curthread = _get_curthread();
72	struct timespec ts, ts2, *tsp;
73	void *tmp;
74	long tid;
75	int oldcancel;
76	int ret = 0;
77
78	if (pthread == NULL)
79		return (EINVAL);
80
81	if (pthread == curthread)
82		return (EDEADLK);
83
84	THREAD_LIST_LOCK(curthread);
85	if ((ret = _thr_find_thread(curthread, pthread, 1)) != 0) {
86		ret = ESRCH;
87	} else if ((pthread->tlflags & TLFLAGS_DETACHED) != 0) {
88		ret = ESRCH;
89	} else if (pthread->joiner != NULL) {
90		/* Multiple joiners are not supported. */
91		ret = ENOTSUP;
92	}
93	if (ret) {
94		THREAD_LIST_UNLOCK(curthread);
95		return (ret);
96	}
97	/* Set the running thread to be the joiner: */
98	pthread->joiner = curthread;
99
100	THREAD_LIST_UNLOCK(curthread);
101
102	THR_CLEANUP_PUSH(curthread, backout_join, pthread);
103	oldcancel = _thr_cancel_enter(curthread);
104
105	tid = pthread->tid;
106	while (pthread->tid != TID_TERMINATED) {
107		if (abstime != NULL) {
108			clock_gettime(CLOCK_REALTIME, &ts);
109			TIMESPEC_SUB(&ts2, abstime, &ts);
110			if (ts2.tv_sec < 0) {
111				ret = ETIMEDOUT;
112				break;
113			}
114			tsp = &ts2;
115		} else
116			tsp = NULL;
117		ret = _thr_umtx_wait(&pthread->tid, tid, tsp);
118		if (ret == ETIMEDOUT)
119			break;
120	}
121
122	_thr_cancel_leave(curthread, oldcancel);
123	THR_CLEANUP_POP(curthread, 0);
124
125	if (ret == ETIMEDOUT) {
126		THREAD_LIST_LOCK(curthread);
127		pthread->joiner = NULL;
128		THREAD_LIST_UNLOCK(curthread);
129	} else {
130		ret = 0;
131		tmp = pthread->ret;
132		THREAD_LIST_LOCK(curthread);
133		pthread->tlflags |= TLFLAGS_DETACHED;
134		pthread->joiner = NULL;
135		THR_GCLIST_ADD(pthread);
136		THREAD_LIST_UNLOCK(curthread);
137
138		if (thread_return != NULL)
139			*thread_return = tmp;
140	}
141	return (ret);
142}
143