1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
|
/* $OpenBSD: uthread_join.c,v 1.10 2002/01/19 23:49:32 fgsch Exp $ */
/*
* Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD: uthread_join.c,v 1.9 1999/08/28 00:03:37 peter Exp $
*/
#include <errno.h>
#ifdef _THREAD_SAFE
#include <pthread.h>
#include "pthread_private.h"
int
pthread_join(pthread_t pthread, void **thread_return)
{
struct pthread *curthread = _get_curthread();
int ret = 0;
pthread_t thread;
_thread_enter_cancellation_point();
/* Check if the caller has specified an invalid thread: */
if (pthread == NULL || pthread->magic != PTHREAD_MAGIC) {
/* Invalid thread: */
_thread_leave_cancellation_point();
return (EINVAL);
}
/* Check if the caller has specified itself: */
if (pthread == curthread) {
/* Avoid a deadlock condition: */
_thread_leave_cancellation_point();
return (EDEADLK);
}
/*
* Lock the garbage collector mutex to ensure that the garbage
* collector is not using the dead thread list.
*/
if (pthread_mutex_lock(&_gc_mutex) != 0)
PANIC("Cannot lock gc mutex");
/*
* Defer signals to protect the thread list from access
* by the signal handler:
*/
_thread_kern_sig_defer();
/*
* Unlock the garbage collector mutex, now that the garbage collector
* can't be run:
*/
if (pthread_mutex_unlock(&_gc_mutex) != 0)
PANIC("Cannot unlock gc mutex");
/*
* Search for the specified thread in the list of active threads. This
* is done manually here rather than calling _find_thread() because
* the searches in _thread_list and _dead_list (as well as setting up
* join/detach state) have to be done atomically.
*/
TAILQ_FOREACH(thread, &_thread_list, tle) {
if (thread == pthread)
break;
}
if (thread == NULL) {
/*
* Search for the specified thread in the list of dead threads:
*/
TAILQ_FOREACH(thread, &_dead_list, dle) {
if (thread == pthread)
break;
}
}
/* Check if the thread was not found or has been detached: */
if (thread == NULL ||
((pthread->attr.flags & PTHREAD_DETACHED) != 0)) {
/* Undefer and handle pending signals, yielding if necessary: */
_thread_kern_sig_undefer();
/* Return an error: */
ret = ESRCH;
} else if (pthread->joiner != NULL) {
/* Undefer and handle pending signals, yielding if necessary: */
_thread_kern_sig_undefer();
/* Multiple joiners are not supported. */
ret = ENOTSUP;
/* Check if the thread is not dead: */
} else if (pthread->state != PS_DEAD) {
/* Set the running thread to be the joiner: */
pthread->joiner = curthread;
/* Keep track of which thread we're joining to: */
curthread->join_status.thread = pthread;
while (curthread->join_status.thread == pthread) {
/* Schedule the next thread: */
_thread_kern_sched_state(PS_JOIN, __FILE__, __LINE__);
}
/*
* The thread return value and error are set by the thread we're
* joining to when it exits or detaches:
*/
ret = curthread->join_status.error;
if ((ret == 0) && (thread_return != NULL))
*thread_return = curthread->join_status.ret;
} else {
/*
* The thread exited (is dead) without being detached, and no
* thread has joined it.
*/
/* Check if the return value is required: */
if (thread_return != NULL) {
/* Return the thread's return value: */
*thread_return = pthread->ret;
}
/* Make the thread collectable by the garbage collector. */
pthread->attr.flags |= PTHREAD_DETACHED;
/* Undefer and handle pending signals, yielding if necessary: */
_thread_kern_sig_undefer();
}
_thread_leave_cancellation_point();
/* Return the completion status: */
return (ret);
}
#endif
|
