thr_join.c revision 212536 
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 212536 2010-09-13 07:03:01Z davidxu $
27 *
28 */
29
30#include "namespace.h"
31#include <errno.h>
32#include <pthread.h>
33#include "un-namespace.h"
34
35#include "thr_private.h"
36
37int	_pthread_timedjoin_np(pthread_t pthread, void **thread_return,
38	const struct timespec *abstime);
39static int join_common(pthread_t, void **, const struct timespec *);
40
41__weak_reference(_pthread_join, pthread_join);
42__weak_reference(_pthread_timedjoin_np, pthread_timedjoin_np);
43
44static void backout_join(void *arg)
45{
46	struct pthread *pthread = (struct pthread *)arg;
47	struct pthread *curthread = _get_curthread();
48
49	THR_THREAD_LOCK(curthread, pthread);
50	pthread->joiner = NULL;
51	THR_THREAD_LOCK(curthread, pthread);
52}
53
54int
55_pthread_join(pthread_t pthread, void **thread_return)
56{
57	return (join_common(pthread, thread_return, NULL));
58}
59
60int
61_pthread_timedjoin_np(pthread_t pthread, void **thread_return,
62	const struct timespec *abstime)
63{
64	if (abstime == NULL || abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
65	    abstime->tv_nsec >= 1000000000)
66		return (EINVAL);
67
68	return (join_common(pthread, thread_return, abstime));
69}
70
71/*
72 * Cancellation behavior:
73 *   if the thread is canceled, joinee is not recycled.
74 */
75static int
76join_common(pthread_t pthread, void **thread_return,
77	const struct timespec *abstime)
78{
79	struct pthread *curthread = _get_curthread();
80	struct timespec ts, ts2, *tsp;
81	void *tmp;
82	long tid;
83	int ret = 0;
84
85	if (pthread == NULL)
86		return (EINVAL);
87
88	if (pthread == curthread)
89		return (EDEADLK);
90
91	if ((ret = _thr_find_thread(curthread, pthread, 1)) != 0)
92		return (ESRCH);
93
94	if ((pthread->flags & THR_FLAGS_DETACHED) != 0) {
95		ret = EINVAL;
96	} else if (pthread->joiner != NULL) {
97		/* Multiple joiners are not supported. */
98		ret = ENOTSUP;
99	}
100	if (ret) {
101		THR_THREAD_UNLOCK(curthread, pthread);
102		return (ret);
103	}
104	/* Set the running thread to be the joiner: */
105	pthread->joiner = curthread;
106
107	THR_THREAD_UNLOCK(curthread, pthread);
108
109	THR_CLEANUP_PUSH(curthread, backout_join, pthread);
110	_thr_cancel_enter(curthread);
111
112	tid = pthread->tid;
113	while (pthread->tid != TID_TERMINATED) {
114		_thr_testcancel(curthread);
115		if (abstime != NULL) {
116			clock_gettime(CLOCK_REALTIME, &ts);
117			TIMESPEC_SUB(&ts2, abstime, &ts);
118			if (ts2.tv_sec < 0) {
119				ret = ETIMEDOUT;
120				break;
121			}
122			tsp = &ts2;
123		} else
124			tsp = NULL;
125		ret = _thr_umtx_wait(&pthread->tid, tid, tsp);
126		if (ret == ETIMEDOUT)
127			break;
128	}
129
130	_thr_cancel_leave(curthread, 0);
131	THR_CLEANUP_POP(curthread, 0);
132
133	if (ret == ETIMEDOUT) {
134		THR_THREAD_LOCK(curthread, pthread);
135		pthread->joiner = NULL;
136		THR_THREAD_UNLOCK(curthread, pthread);
137	} else {
138		ret = 0;
139		tmp = pthread->ret;
140		THR_THREAD_LOCK(curthread, pthread);
141		pthread->flags |= THR_FLAGS_DETACHED;
142		pthread->joiner = NULL;
143		_thr_try_gc(curthread, pthread); /* thread lock released */
144
145		if (thread_return != NULL)
146			*thread_return = tmp;
147	}
148	return (ret);
149}
150