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thr_join.c (127569) thr_join.c (129484)
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

--- 15 unchanged lines hidden (view full) ---

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 *
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

--- 15 unchanged lines hidden (view full) ---

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: head/lib/libthr/thread/thr_join.c 127569 2004-03-29 13:53:43Z mtm $
32 * $FreeBSD: head/lib/libthr/thread/thr_join.c 129484 2004-05-20 12:06:16Z mtm $
33 */
34#include <errno.h>
35#include <pthread.h>
36#include <stdlib.h>
37#include "thr_private.h"
38
39__weak_reference(_pthread_join, pthread_join);
40
41int
42_pthread_join(pthread_t pthread, void **thread_return)
43{
44 int ret = 0;
45 pthread_t thread;
46
33 */
34#include <errno.h>
35#include <pthread.h>
36#include <stdlib.h>
37#include "thr_private.h"
38
39__weak_reference(_pthread_join, pthread_join);
40
41int
42_pthread_join(pthread_t pthread, void **thread_return)
43{
44 int ret = 0;
45 pthread_t thread;
46
47 _thread_enter_cancellation_point();
48
49 /* Check if the caller has specified an invalid thread: */
47 /* Check if the caller has specified an invalid thread: */
50 if (pthread->magic != PTHREAD_MAGIC) {
48 if (pthread->magic != PTHREAD_MAGIC)
51 /* Invalid thread: */
49 /* Invalid thread: */
52 _thread_leave_cancellation_point();
53 return(EINVAL);
50 return(EINVAL);
54 }
55
56 /* Check if the caller has specified itself: */
51
52 /* Check if the caller has specified itself: */
57 if (pthread == curthread) {
53 if (pthread == curthread)
58 /* Avoid a deadlock condition: */
54 /* Avoid a deadlock condition: */
59 _thread_leave_cancellation_point();
60 return(EDEADLK);
55 return(EDEADLK);
61 }
62
63 /*
64 * Search for the specified thread in the list of active threads. This
65 * is done manually here rather than calling _find_thread() because
66 * the searches in _thread_list and _dead_list (as well as setting up
67 * join/detach state) have to be done atomically.
68 */
56
57 /*
58 * Search for the specified thread in the list of active threads. This
59 * is done manually here rather than calling _find_thread() because
60 * the searches in _thread_list and _dead_list (as well as setting up
61 * join/detach state) have to be done atomically.
62 */
63 _thread_sigblock();
69 DEAD_LIST_LOCK;
70 THREAD_LIST_LOCK;
64 DEAD_LIST_LOCK;
65 THREAD_LIST_LOCK;
71 TAILQ_FOREACH(thread, &_thread_list, tle)
72 if (thread == pthread) {
73 UMTX_LOCK(&pthread->lock);
74 break;
66 if (!pthread->isdead) {
67 TAILQ_FOREACH(thread, &_thread_list, tle) {
68 if (thread == pthread) {
69 PTHREAD_LOCK(pthread);
70 break;
71 }
75 }
72 }
76
77 if (thread == NULL)
78 /*
79 * Search for the specified thread in the list of dead threads:
80 */
81 TAILQ_FOREACH(thread, &_dead_list, dle)
73 } else {
74 TAILQ_FOREACH(thread, &_dead_list, dle) {
82 if (thread == pthread) {
75 if (thread == pthread) {
83 UMTX_LOCK(&pthread->lock);
76 PTHREAD_LOCK(pthread);
84 break;
85 }
77 break;
78 }
79 }
80 }
86
87 /* Check if the thread was not found or has been detached: */
88 if (thread == NULL) {
89 THREAD_LIST_UNLOCK;
90 DEAD_LIST_UNLOCK;
81
82 /* Check if the thread was not found or has been detached: */
83 if (thread == NULL) {
84 THREAD_LIST_UNLOCK;
85 DEAD_LIST_UNLOCK;
86 _thread_sigunblock();
91 ret = ESRCH;
92 goto out;
93 }
94 if ((pthread->attr.flags & PTHREAD_DETACHED) != 0) {
87 ret = ESRCH;
88 goto out;
89 }
90 if ((pthread->attr.flags & PTHREAD_DETACHED) != 0) {
95 UMTX_UNLOCK(&pthread->lock);
91 PTHREAD_UNLOCK(pthread);
96 THREAD_LIST_UNLOCK;
97 DEAD_LIST_UNLOCK;
92 THREAD_LIST_UNLOCK;
93 DEAD_LIST_UNLOCK;
94 _thread_sigunblock();
98 ret = EINVAL;
99 goto out;
100 }
101
102 if (pthread->joiner != NULL) {
103 /* Multiple joiners are not supported. */
104 /* XXXTHR - support multiple joiners. */
95 ret = EINVAL;
96 goto out;
97 }
98
99 if (pthread->joiner != NULL) {
100 /* Multiple joiners are not supported. */
101 /* XXXTHR - support multiple joiners. */
105 UMTX_UNLOCK(&pthread->lock);
102 PTHREAD_UNLOCK(pthread);
106 THREAD_LIST_UNLOCK;
107 DEAD_LIST_UNLOCK;
103 THREAD_LIST_UNLOCK;
104 DEAD_LIST_UNLOCK;
105 _thread_sigunblock();
108 ret = ENOTSUP;
109 goto out;
110
111 }
112
113 /* Check if the thread is not dead: */
106 ret = ENOTSUP;
107 goto out;
108
109 }
110
111 /* Check if the thread is not dead: */
114 if (pthread->state != PS_DEAD) {
112 if (!pthread->isdead) {
115 /* Set the running thread to be the joiner: */
116 pthread->joiner = curthread;
113 /* Set the running thread to be the joiner: */
114 pthread->joiner = curthread;
117 UMTX_UNLOCK(&pthread->lock);
118 _thread_critical_enter(curthread);
115 PTHREAD_UNLOCK(pthread);
119
120 /* Keep track of which thread we're joining to: */
121 curthread->join_status.thread = pthread;
122
123 while (curthread->join_status.thread == pthread) {
116
117 /* Keep track of which thread we're joining to: */
118 curthread->join_status.thread = pthread;
119
120 while (curthread->join_status.thread == pthread) {
124 PTHREAD_SET_STATE(curthread, PS_JOIN);
125 /* Wait for our signal to wake up. */
121 /* Wait for our signal to wake up. */
126 _thread_critical_exit(curthread);
127 THREAD_LIST_UNLOCK;
128 DEAD_LIST_UNLOCK;
122 THREAD_LIST_UNLOCK;
123 DEAD_LIST_UNLOCK;
124 _thread_sigunblock();
125 if (curthread->cancellation != CS_NULL)
126 pthread->joiner = NULL;
127 _thread_enter_cancellation_point();
128
129 /*
130 * XXX - Workaround to make a join a cancellation
131 * point. Must find a better solution.
132 */
133 PTHREAD_LOCK(curthread);
134 curthread->flags |= PTHREAD_FLAGS_SUSPENDED;
135 PTHREAD_UNLOCK(curthread);
129 ret = _thread_suspend(curthread, NULL);
130 if (ret != 0 && ret != EAGAIN && ret != EINTR)
131 PANIC("Unable to suspend in join.");
136 ret = _thread_suspend(curthread, NULL);
137 if (ret != 0 && ret != EAGAIN && ret != EINTR)
138 PANIC("Unable to suspend in join.");
139 PTHREAD_LOCK(curthread);
140 curthread->flags &= ~PTHREAD_FLAGS_SUSPENDED;
141 PTHREAD_UNLOCK(curthread);
142 if (curthread->cancellation != CS_NULL)
143 pthread->joiner = NULL;
144 _thread_leave_cancellation_point();
132
133 /*
134 * XXX - For correctness reasons.
135 * We must aquire these in the same order and also
145
146 /*
147 * XXX - For correctness reasons.
148 * We must aquire these in the same order and also
136 * importantly, release in the same order, order because
149 * importantly, release in the same order because
137 * otherwise we might deadlock with the joined thread
138 * when we attempt to release one of these locks.
139 */
150 * otherwise we might deadlock with the joined thread
151 * when we attempt to release one of these locks.
152 */
153 _thread_sigblock();
140 DEAD_LIST_LOCK;
141 THREAD_LIST_LOCK;
154 DEAD_LIST_LOCK;
155 THREAD_LIST_LOCK;
142 _thread_critical_enter(curthread);
143 }
144
145 /*
146 * The thread return value and error are set by the thread we're
147 * joining to when it exits or detaches:
148 */
149 ret = curthread->join_status.error;
150 if ((ret == 0) && (thread_return != NULL))
151 *thread_return = curthread->join_status.ret;
156 }
157
158 /*
159 * The thread return value and error are set by the thread we're
160 * joining to when it exits or detaches:
161 */
162 ret = curthread->join_status.error;
163 if ((ret == 0) && (thread_return != NULL))
164 *thread_return = curthread->join_status.ret;
152 _thread_critical_exit(curthread);
153 THREAD_LIST_UNLOCK;
154 DEAD_LIST_UNLOCK;
165 THREAD_LIST_UNLOCK;
166 DEAD_LIST_UNLOCK;
167 _thread_sigunblock();
155 } else {
156 /*
157 * The thread exited (is dead) without being detached, and no
158 * thread has joined it.
159 */
160
161 /* Check if the return value is required: */
162 if (thread_return != NULL) {
163 /* Return the thread's return value: */
164 *thread_return = pthread->ret;
165 }
166
167 /* Free all remaining memory allocated to the thread. */
168 pthread->attr.flags |= PTHREAD_DETACHED;
168 } else {
169 /*
170 * The thread exited (is dead) without being detached, and no
171 * thread has joined it.
172 */
173
174 /* Check if the return value is required: */
175 if (thread_return != NULL) {
176 /* Return the thread's return value: */
177 *thread_return = pthread->ret;
178 }
179
180 /* Free all remaining memory allocated to the thread. */
181 pthread->attr.flags |= PTHREAD_DETACHED;
169 UMTX_UNLOCK(&pthread->lock);
182 PTHREAD_UNLOCK(pthread);
170 TAILQ_REMOVE(&_dead_list, pthread, dle);
171 deadlist_free_onethread(pthread);
172 THREAD_LIST_UNLOCK;
173 DEAD_LIST_UNLOCK;
183 TAILQ_REMOVE(&_dead_list, pthread, dle);
184 deadlist_free_onethread(pthread);
185 THREAD_LIST_UNLOCK;
186 DEAD_LIST_UNLOCK;
187 _thread_sigunblock();
174 }
175
176out:
177 _thread_leave_cancellation_point();
178
179 /* Return the completion status: */
180 return (ret);
181}
188 }
189
190out:
191 _thread_leave_cancellation_point();
192
193 /* Return the completion status: */
194 return (ret);
195}