xref: /freebsd/lib/libthr/thread/thr_join.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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  * $FreeBSD$
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 
37 int	_pthread_timedjoin_np(pthread_t pthread, void **thread_return,
38 	const struct timespec *abstime);
39 static 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 
44 static void backout_join(void *arg)
45 {
46 	struct pthread *curthread = _get_curthread();
47 	struct pthread *pthread = (struct pthread *)arg;
48 
49 	THREAD_LIST_LOCK(curthread);
50 	pthread->joiner = NULL;
51 	THREAD_LIST_UNLOCK(curthread);
52 }
53 
54 int
55 _pthread_join(pthread_t pthread, void **thread_return)
56 {
57 	return (join_common(pthread, thread_return, NULL));
58 }
59 
60 int
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 static int
72 join_common(pthread_t pthread, void **thread_return,
73 	const struct timespec *abstime)
74 {
75 	struct pthread *curthread = _get_curthread();
76 	struct timespec ts, ts2, *tsp;
77 	void *tmp;
78 	long tid;
79 	int ret = 0;
80 
81 	if (pthread == NULL)
82 		return (EINVAL);
83 
84 	if (pthread == curthread)
85 		return (EDEADLK);
86 
87 	THREAD_LIST_LOCK(curthread);
88 	if ((ret = _thr_find_thread(curthread, pthread, 1)) != 0) {
89 		ret = ESRCH;
90 	} else if ((pthread->tlflags & TLFLAGS_DETACHED) != 0) {
91 		ret = EINVAL;
92 	} else if (pthread->joiner != NULL) {
93 		/* Multiple joiners are not supported. */
94 		ret = ENOTSUP;
95 	}
96 	if (ret) {
97 		THREAD_LIST_UNLOCK(curthread);
98 		return (ret);
99 	}
100 	/* Set the running thread to be the joiner: */
101 	pthread->joiner = curthread;
102 
103 	THREAD_LIST_UNLOCK(curthread);
104 
105 	THR_CLEANUP_PUSH(curthread, backout_join, pthread);
106 	_thr_cancel_enter(curthread);
107 
108 	tid = pthread->tid;
109 	while (pthread->tid != TID_TERMINATED) {
110 		if (abstime != NULL) {
111 			clock_gettime(CLOCK_REALTIME, &ts);
112 			TIMESPEC_SUB(&ts2, abstime, &ts);
113 			if (ts2.tv_sec < 0) {
114 				ret = ETIMEDOUT;
115 				break;
116 			}
117 			tsp = &ts2;
118 		} else
119 			tsp = NULL;
120 		ret = _thr_umtx_wait(&pthread->tid, tid, tsp);
121 		if (ret == ETIMEDOUT)
122 			break;
123 	}
124 
125 	_thr_cancel_leave(curthread);
126 	THR_CLEANUP_POP(curthread, 0);
127 
128 	if (ret == ETIMEDOUT) {
129 		THREAD_LIST_LOCK(curthread);
130 		pthread->joiner = NULL;
131 		THREAD_LIST_UNLOCK(curthread);
132 	} else {
133 		ret = 0;
134 		tmp = pthread->ret;
135 		THREAD_LIST_LOCK(curthread);
136 		pthread->tlflags |= TLFLAGS_DETACHED;
137 		pthread->joiner = NULL;
138 		THR_GCLIST_ADD(pthread);
139 		THREAD_LIST_UNLOCK(curthread);
140 
141 		if (thread_return != NULL)
142 			*thread_return = tmp;
143 	}
144 	return (ret);
145 }
146