xref: /freebsd/lib/libthr/thread/thr_suspend_np.c (revision 262e143bd46171a6415a5b28af260a5efa2a3db8)
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. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by John Birrell.
16  * 4. Neither the name of the author nor the names of any co-contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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  * $FreeBSD$
33  */
34 
35 #include <errno.h>
36 #include <pthread.h>
37 
38 #include "thr_private.h"
39 
40 static void suspend_common(struct pthread *thread);
41 
42 __weak_reference(_pthread_suspend_np, pthread_suspend_np);
43 __weak_reference(_pthread_suspend_all_np, pthread_suspend_all_np);
44 
45 /* Suspend a thread: */
46 int
47 _pthread_suspend_np(pthread_t thread)
48 {
49 	struct pthread *curthread = _get_curthread();
50 	int ret;
51 
52 	/* Suspending the current thread doesn't make sense. */
53 	if (thread == _get_curthread())
54 		ret = EDEADLK;
55 
56 	/* Add a reference to the thread: */
57 	else if ((ret = _thr_ref_add(curthread, thread, /*include dead*/0))
58 	    == 0) {
59 		/* Lock the threads scheduling queue: */
60 		THR_THREAD_LOCK(curthread, thread);
61 		suspend_common(thread);
62 		/* Unlock the threads scheduling queue: */
63 		THR_THREAD_UNLOCK(curthread, thread);
64 
65 		/* Don't forget to remove the reference: */
66 		_thr_ref_delete(curthread, thread);
67 	}
68 	return (ret);
69 }
70 
71 void
72 _pthread_suspend_all_np(void)
73 {
74 	struct pthread	*curthread = _get_curthread();
75 	struct pthread	*thread;
76 
77 	/* Take the thread list lock: */
78 	THREAD_LIST_LOCK(curthread);
79 
80 	TAILQ_FOREACH(thread, &_thread_list, tle) {
81 		if (thread != curthread) {
82 			THR_THREAD_LOCK(curthread, thread);
83 			suspend_common(thread);
84 			THR_THREAD_UNLOCK(curthread, thread);
85 		}
86 	}
87 
88 	/* Release the thread list lock: */
89 	THREAD_LIST_UNLOCK(curthread);
90 }
91 
92 static void
93 suspend_common(struct pthread *thread)
94 {
95 	if (thread->state != PS_DEAD) {
96 		thread->flags |= THR_FLAGS_NEED_SUSPEND;
97 		_thr_send_sig(thread, SIGCANCEL);
98 	}
99 }
100