1 /*
2 * Copyright (c) 1995-1998 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. Neither the name of the author nor the names of any co-contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 */
30
31 #include "namespace.h"
32 #include <errno.h>
33 #include <pthread.h>
34 #include <pthread_np.h>
35 #include "un-namespace.h"
36
37 #include "thr_private.h"
38
39 static int suspend_common(pthread_t, pthread_t, int);
40
41 /* Suspend a thread: */
42 int
_pthread_suspend_np(pthread_t thread)43 _pthread_suspend_np(pthread_t thread)
44 {
45 pthread_t curthread = tls_get_curthread();
46 int ret;
47
48 /* Suspending the current thread doesn't make sense. */
49 if (thread == curthread)
50 ret = EDEADLK;
51
52 /* Add a reference to the thread: */
53 else if ((ret = _thr_ref_add(curthread, thread, /*include dead*/0))
54 == 0) {
55 /* Lock the threads scheduling queue: */
56 THR_THREAD_LOCK(curthread, thread);
57 suspend_common(curthread, thread, 1);
58 /* Unlock the threads scheduling queue: */
59 THR_THREAD_UNLOCK(curthread, thread);
60
61 /* Don't forget to remove the reference: */
62 _thr_ref_delete(curthread, thread);
63 }
64 return (ret);
65 }
66
67 void
_pthread_suspend_all_np(void)68 _pthread_suspend_all_np(void)
69 {
70 pthread_t curthread = tls_get_curthread();
71 pthread_t thread;
72 int ret;
73
74 THREAD_LIST_LOCK(curthread);
75
76 TAILQ_FOREACH(thread, &_thread_list, tle) {
77 if (thread != curthread) {
78 THR_THREAD_LOCK(curthread, thread);
79 if (thread->state != PS_DEAD &&
80 !(thread->flags & THR_FLAGS_SUSPENDED))
81 thread->flags |= THR_FLAGS_NEED_SUSPEND;
82 THR_THREAD_UNLOCK(curthread, thread);
83 }
84 }
85 /* thr_kill(-1, SIGCANCEL); */
86
87 restart:
88 TAILQ_FOREACH(thread, &_thread_list, tle) {
89 if (thread != curthread) {
90 /* First try to suspend the thread without waiting */
91 THR_THREAD_LOCK(curthread, thread);
92 ret = suspend_common(curthread, thread, 0);
93 if (ret == 0) {
94 /* Can not suspend, try to wait */
95 thread->refcount++;
96 THREAD_LIST_UNLOCK(curthread);
97 suspend_common(curthread, thread, 1);
98 THR_THREAD_UNLOCK(curthread, thread);
99 THREAD_LIST_LOCK(curthread);
100 _thr_ref_delete_unlocked(curthread, thread);
101 /*
102 * Because we were blocked, things may have
103 * been changed, we have to restart the
104 * process.
105 */
106 goto restart;
107 }
108 THR_THREAD_UNLOCK(curthread, thread);
109 }
110 }
111
112 THREAD_LIST_UNLOCK(curthread);
113 }
114
115 static int
suspend_common(pthread_t curthread,pthread_t thread,int waitok)116 suspend_common(pthread_t curthread, pthread_t thread, int waitok)
117 {
118 umtx_t tmp;
119
120 while (thread->state != PS_DEAD &&
121 !(thread->flags & THR_FLAGS_SUSPENDED)) {
122 thread->flags |= THR_FLAGS_NEED_SUSPEND;
123 tmp = thread->cycle;
124 _thr_send_sig(thread, SIGCANCEL);
125 THR_THREAD_UNLOCK(curthread, thread);
126 if (waitok) {
127 _thr_umtx_wait(&thread->cycle, tmp, NULL, 0);
128 THR_THREAD_LOCK(curthread, thread);
129 } else {
130 THR_THREAD_LOCK(curthread, thread);
131 return (0);
132 }
133 }
134
135 return (1);
136 }
137
138 __strong_reference(_pthread_suspend_np, pthread_suspend_np);
139 __strong_reference(_pthread_suspend_all_np, pthread_suspend_all_np);
140