thr_find_thread.c revision 113661 
1/*
2 * Copyright (c) 2003 Daniel Eischen <deischen@freebsd.org>
3 * Copyright (c) 1998 John Birrell <jb@cimlogic.com.au>.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 *    must display the following acknowledgement:
16 *	This product includes software developed by John Birrell.
17 * 4. Neither the name of the author nor the names of any co-contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * $FreeBSD: head/lib/libkse/thread/thr_find_thread.c 113661 2003-04-18 07:09:43Z deischen $
34 */
35#include <errno.h>
36#include <pthread.h>
37#include "thr_private.h"
38
39/*
40 * Find a thread in the linked list of active threads and add a reference
41 * to it.  Threads with positive reference counts will not be deallocated
42 * until all references are released.
43 */
44int
45_thr_ref_add(struct pthread *curthread, struct pthread *thread,
46    int include_dead)
47{
48	kse_critical_t crit;
49	struct pthread *pthread;
50
51	if (thread == NULL)
52		/* Invalid thread: */
53		return (EINVAL);
54
55	crit = _kse_critical_enter();
56	KSE_LOCK_ACQUIRE(curthread->kse, &_thread_list_lock);
57	TAILQ_FOREACH(pthread, &_thread_list, tle) {
58		if (pthread == thread) {
59			if ((include_dead == 0) &&
60			    ((pthread->state == PS_DEAD) ||
61			    ((pthread->state == PS_DEADLOCK) ||
62			    ((pthread->flags & THR_FLAGS_EXITING) != 0))))
63				pthread = NULL;
64			else {
65				thread->refcount++;
66				curthread->critical_count++;
67			}
68			break;
69		}
70	}
71	KSE_LOCK_RELEASE(curthread->kse, &_thread_list_lock);
72	_kse_critical_leave(crit);
73
74	/* Return zero if the thread exists: */
75	return ((pthread != NULL) ? 0 : ESRCH);
76}
77
78void
79_thr_ref_delete(struct pthread *curthread, struct pthread *thread)
80{
81	kse_critical_t crit;
82
83	if (thread != NULL) {
84		crit = _kse_critical_enter();
85		KSE_LOCK_ACQUIRE(curthread->kse, &_thread_list_lock);
86		thread->refcount--;
87		curthread->critical_count--;
88		KSE_LOCK_RELEASE(curthread->kse, &_thread_list_lock);
89		_kse_critical_leave(crit);
90	}
91}
92