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 * $FreeBSD$
30 */
31
32#include "namespace.h"
33#include <errno.h>
34#include <pthread.h>
35#include "un-namespace.h"
36#include "thr_private.h"
37
38int	_pthread_suspend_np(pthread_t thread);
39void	_pthread_suspend_all_np(void);
40
41static void suspend_common(struct pthread *thread);
42
43__weak_reference(_pthread_suspend_np, pthread_suspend_np);
44__weak_reference(_pthread_suspend_all_np, pthread_suspend_all_np);
45
46/* Suspend a thread: */
47int
48_pthread_suspend_np(pthread_t thread)
49{
50	struct pthread *curthread = _get_curthread();
51	int ret;
52
53	/* Suspending the current thread doesn't make sense. */
54	if (thread == _get_curthread())
55		ret = EDEADLK;
56
57	/* Add a reference to the thread: */
58	else if ((ret = _thr_ref_add(curthread, thread, /*include dead*/0))
59	    == 0) {
60		/* Lock the threads scheduling queue: */
61		THR_SCHED_LOCK(curthread, thread);
62		suspend_common(thread);
63		/* Unlock the threads scheduling queue: */
64		THR_SCHED_UNLOCK(curthread, thread);
65
66		/* Don't forget to remove the reference: */
67		_thr_ref_delete(curthread, thread);
68	}
69	return (ret);
70}
71
72void
73_pthread_suspend_all_np(void)
74{
75	struct pthread	*curthread = _get_curthread();
76	struct pthread	*thread;
77	kse_critical_t crit;
78
79	/* Take the thread list lock: */
80	crit = _kse_critical_enter();
81	KSE_LOCK_ACQUIRE(curthread->kse, &_thread_list_lock);
82
83	TAILQ_FOREACH(thread, &_thread_list, tle) {
84		if (thread != curthread) {
85			THR_SCHED_LOCK(curthread, thread);
86			suspend_common(thread);
87			THR_SCHED_UNLOCK(curthread, thread);
88		}
89	}
90
91	/* Release the thread list lock: */
92	KSE_LOCK_RELEASE(curthread->kse, &_thread_list_lock);
93	_kse_critical_leave(crit);
94}
95
96void
97suspend_common(struct pthread *thread)
98{
99	if ((thread->state != PS_DEAD) &&
100	    (thread->state != PS_DEADLOCK) &&
101	    ((thread->flags & THR_FLAGS_EXITING) == 0)) {
102		thread->flags |= THR_FLAGS_SUSPENDED;
103		if ((thread->flags & THR_FLAGS_IN_RUNQ) != 0) {
104			THR_RUNQ_REMOVE(thread);
105			THR_SET_STATE(thread, PS_SUSPENDED);
106		}
107#ifdef NOT_YET
108		if ((thread->attr.flags & PTHREAD_SCOPE_SYSTEM) != 0)
109			/* ??? */
110#endif
111	}
112}
113