1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2005, David Xu <davidxu@freebsd.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice unmodified, this list of conditions, and the following
12 * disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include "namespace.h"
30 #include <errno.h>
31 #include <pthread.h>
32 #include "un-namespace.h"
33
34 #include "thr_private.h"
35
36 int _pthread_peekjoin_np(pthread_t pthread, void **thread_return);
37 int _pthread_tryjoin_np(pthread_t pthread, void **thread_return);
38 int _pthread_timedjoin_np(pthread_t pthread, void **thread_return,
39 const struct timespec *abstime);
40 static int join_common(pthread_t, void **, const struct timespec *, bool peek,
41 bool try);
42
43 __weak_reference(_thr_join, pthread_join);
44 __weak_reference(_thr_join, _pthread_join);
45 __weak_reference(_pthread_timedjoin_np, pthread_timedjoin_np);
46 __weak_reference(_pthread_peekjoin_np, pthread_peekjoin_np);
47 __weak_reference(_pthread_tryjoin_np, pthread_tryjoin_np);
48
49 static void
backout_join(struct pthread * pthread,struct pthread * curthread)50 backout_join(struct pthread *pthread, struct pthread *curthread)
51 {
52 THR_THREAD_LOCK(curthread, pthread);
53 pthread->joiner = NULL;
54 THR_THREAD_UNLOCK(curthread, pthread);
55 }
56
57 static void
backout_join_pop(void * arg)58 backout_join_pop(void *arg)
59 {
60 struct pthread *pthread = (struct pthread *)arg;
61 struct pthread *curthread = _get_curthread();
62
63 backout_join(pthread, curthread);
64 }
65
66 int
_thr_join(pthread_t pthread,void ** thread_return)67 _thr_join(pthread_t pthread, void **thread_return)
68 {
69 return (join_common(pthread, thread_return, NULL, false, false));
70 }
71
72 int
_pthread_timedjoin_np(pthread_t pthread,void ** thread_return,const struct timespec * abstime)73 _pthread_timedjoin_np(pthread_t pthread, void **thread_return,
74 const struct timespec *abstime)
75 {
76 if (abstime == NULL || abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
77 abstime->tv_nsec >= 1000000000)
78 return (EINVAL);
79
80 return (join_common(pthread, thread_return, abstime, false, false));
81 }
82
83 int
_pthread_peekjoin_np(pthread_t pthread,void ** thread_return)84 _pthread_peekjoin_np(pthread_t pthread, void **thread_return)
85 {
86 return (join_common(pthread, thread_return, NULL, true, false));
87 }
88
89 int
_pthread_tryjoin_np(pthread_t pthread,void ** thread_return)90 _pthread_tryjoin_np(pthread_t pthread, void **thread_return)
91 {
92 return (join_common(pthread, thread_return, NULL, false, true));
93 }
94
95 static void
join_common_joined(struct pthread * pthread,struct pthread * curthread,void ** thread_return)96 join_common_joined(struct pthread *pthread, struct pthread *curthread,
97 void **thread_return)
98 {
99 void *tmp;
100
101 tmp = pthread->ret;
102 pthread->flags |= THR_FLAGS_DETACHED;
103 pthread->joiner = NULL;
104 _thr_try_gc(curthread, pthread); /* thread lock released */
105
106 if (thread_return != NULL)
107 *thread_return = tmp;
108 }
109
110 /*
111 * Cancellation behavior:
112 * if the thread is canceled, joinee is not recycled.
113 */
114 static int
join_common(pthread_t pthread,void ** thread_return,const struct timespec * abstime,bool peek,bool try)115 join_common(pthread_t pthread, void **thread_return,
116 const struct timespec *abstime, bool peek, bool try)
117 {
118 struct pthread *curthread = _get_curthread();
119 struct timespec ts, ts2, *tsp;
120 long tid;
121 int ret;
122
123 if (pthread == NULL)
124 return (EINVAL);
125
126 if (pthread == curthread)
127 return (EDEADLK);
128
129 if ((ret = _thr_find_thread(curthread, pthread, 1)) != 0)
130 return (ESRCH);
131
132 if ((pthread->flags & THR_FLAGS_DETACHED) != 0) {
133 ret = EINVAL;
134 } else if (pthread->joiner != NULL) {
135 /* Multiple joiners are not supported. */
136 ret = ENOTSUP;
137 }
138 if (ret != 0) {
139 THR_THREAD_UNLOCK(curthread, pthread);
140 return (ret);
141 }
142
143 /* Only peek into status, do not gc the thread. */
144 if (peek) {
145 if (pthread->tid != TID_TERMINATED)
146 ret = EBUSY;
147 else if (thread_return != NULL)
148 *thread_return = pthread->ret;
149 THR_THREAD_UNLOCK(curthread, pthread);
150 return (ret);
151 }
152
153 /* Only try to join. */
154 if (try) {
155 if (pthread->tid != TID_TERMINATED) {
156 THR_THREAD_UNLOCK(curthread, pthread);
157 return (EBUSY);
158 }
159 join_common_joined(pthread, curthread, thread_return);
160 return (0);
161 }
162
163 /* Set the running thread to be the joiner: */
164 pthread->joiner = curthread;
165
166 THR_THREAD_UNLOCK(curthread, pthread);
167
168 THR_CLEANUP_PUSH(curthread, backout_join_pop, pthread);
169 _thr_cancel_enter(curthread);
170
171 tid = pthread->tid;
172 while (pthread->tid != TID_TERMINATED) {
173 _thr_testcancel(curthread);
174 if (abstime != NULL) {
175 clock_gettime(CLOCK_REALTIME, &ts);
176 TIMESPEC_SUB(&ts2, abstime, &ts);
177 if (ts2.tv_sec < 0) {
178 ret = ETIMEDOUT;
179 break;
180 }
181 tsp = &ts2;
182 } else
183 tsp = NULL;
184 ret = _thr_umtx_wait(&pthread->tid, tid, tsp);
185 if (ret == ETIMEDOUT)
186 break;
187 }
188
189 _thr_cancel_leave(curthread, 0);
190 THR_CLEANUP_POP(curthread, 0);
191
192 if (ret == ETIMEDOUT || ret == EBUSY) {
193 backout_join(pthread, curthread);
194 } else {
195 ret = 0;
196 THR_THREAD_LOCK(curthread, pthread);
197 join_common_joined(pthread, curthread, thread_return);
198 }
199 return (ret);
200 }
201