xref: /freebsd/lib/libthr/thread/thr_join.c (revision 262e143bd46171a6415a5b28af260a5efa2a3db8)
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  * $FreeBSD$
33  */
34 
35 #include <errno.h>
36 #include <pthread.h>
37 
38 #include "thr_private.h"
39 
40 static int join_common(pthread_t, void **, const struct timespec *);
41 
42 __weak_reference(_pthread_join, pthread_join);
43 __weak_reference(_pthread_timedjoin_np, pthread_timedjoin_np);
44 
45 static void backout_join(void *arg)
46 {
47 	struct pthread *curthread = _get_curthread();
48 	struct pthread *pthread = (struct pthread *)arg;
49 
50 	THREAD_LIST_LOCK(curthread);
51 	pthread->joiner = NULL;
52 	THREAD_LIST_UNLOCK(curthread);
53 }
54 
55 int
56 _pthread_join(pthread_t pthread, void **thread_return)
57 {
58 	return (join_common(pthread, thread_return, NULL));
59 }
60 
61 int
62 _pthread_timedjoin_np(pthread_t pthread, void **thread_return,
63 	const struct timespec *abstime)
64 {
65 	if (abstime == NULL || abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
66 	    abstime->tv_nsec >= 1000000000)
67 		return (EINVAL);
68 
69 	return (join_common(pthread, thread_return, abstime));
70 }
71 
72 static int
73 join_common(pthread_t pthread, void **thread_return,
74 	const struct timespec *abstime)
75 {
76 	struct pthread *curthread = _get_curthread();
77 	struct timespec ts, ts2, *tsp;
78 	void *tmp;
79 	long tid;
80 	int oldcancel;
81 	int ret = 0;
82 
83 	if (pthread == NULL)
84 		return (EINVAL);
85 
86 	if (pthread == curthread)
87 		return (EDEADLK);
88 
89 	THREAD_LIST_LOCK(curthread);
90 	if ((ret = _thr_find_thread(curthread, pthread, 1)) != 0) {
91 		ret = ESRCH;
92 	} else if ((pthread->tlflags & TLFLAGS_DETACHED) != 0) {
93 		ret = ESRCH;
94 	} else if (pthread->joiner != NULL) {
95 		/* Multiple joiners are not supported. */
96 		ret = ENOTSUP;
97 	}
98 	if (ret) {
99 		THREAD_LIST_UNLOCK(curthread);
100 		return (ret);
101 	}
102 	/* Set the running thread to be the joiner: */
103 	pthread->joiner = curthread;
104 
105 	THREAD_LIST_UNLOCK(curthread);
106 
107 	THR_CLEANUP_PUSH(curthread, backout_join, pthread);
108 	oldcancel = _thr_cancel_enter(curthread);
109 
110 	tid = pthread->tid;
111 	while (pthread->tid != TID_TERMINATED) {
112 		if (abstime != NULL) {
113 			clock_gettime(CLOCK_REALTIME, &ts);
114 			TIMESPEC_SUB(&ts2, abstime, &ts);
115 			if (ts2.tv_sec < 0) {
116 				ret = ETIMEDOUT;
117 				break;
118 			}
119 			tsp = &ts2;
120 		} else
121 			tsp = NULL;
122 		ret = _thr_umtx_wait(&pthread->tid, tid, tsp);
123 		if (ret == ETIMEDOUT)
124 			break;
125 	}
126 
127 	_thr_cancel_leave(curthread, oldcancel);
128 	THR_CLEANUP_POP(curthread, 0);
129 
130 	if (ret == ETIMEDOUT) {
131 		THREAD_LIST_LOCK(curthread);
132 		pthread->joiner = NULL;
133 		THREAD_LIST_UNLOCK(curthread);
134 	} else {
135 		tmp = pthread->ret;
136 		THREAD_LIST_LOCK(curthread);
137 		pthread->tlflags |= TLFLAGS_DETACHED;
138 		pthread->joiner = NULL;
139 		THR_GCLIST_ADD(pthread);
140 		THREAD_LIST_UNLOCK(curthread);
141 
142 		if (thread_return != NULL)
143 			*thread_return = tmp;
144 	}
145 	return (ret);
146 }
147