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. Neither the name of the author nor the names of any co-contributors
15 *    may be used to endorse or promote products derived from this software
16 *    without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 * $FreeBSD$
31 */
32
33#include "namespace.h"
34#include <errno.h>
35#include <pthread.h>
36#include "un-namespace.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	struct kse *curkse;
51
52	if (thread == NULL)
53		/* Invalid thread: */
54		return (EINVAL);
55
56	crit = _kse_critical_enter();
57	curkse = _get_curkse();
58	KSE_LOCK_ACQUIRE(curkse, &_thread_list_lock);
59	pthread = _thr_hash_find(thread);
60	if (pthread) {
61		if ((include_dead == 0) &&
62		    ((pthread->state == PS_DEAD) ||
63		    ((pthread->state == PS_DEADLOCK) ||
64		    ((pthread->flags & THR_FLAGS_EXITING) != 0))))
65			pthread = NULL;
66		else {
67			pthread->refcount++;
68			if (curthread != NULL)
69				curthread->critical_count++;
70		}
71	}
72	KSE_LOCK_RELEASE(curkse, &_thread_list_lock);
73	_kse_critical_leave(crit);
74
75	/* Return zero if the thread exists: */
76	return ((pthread != NULL) ? 0 : ESRCH);
77}
78
79void
80_thr_ref_delete(struct pthread *curthread, struct pthread *thread)
81{
82	kse_critical_t crit;
83	struct kse *curkse;
84
85	if (thread != NULL) {
86		crit = _kse_critical_enter();
87		curkse = _get_curkse();
88		KSE_LOCK_ACQUIRE(curkse, &_thread_list_lock);
89		thread->refcount--;
90		if (curthread != NULL)
91			curthread->critical_count--;
92		if ((thread->refcount == 0) &&
93		    (thread->tlflags & TLFLAGS_GC_SAFE) != 0)
94			THR_GCLIST_ADD(thread);
95		KSE_LOCK_RELEASE(curkse, &_thread_list_lock);
96		_kse_critical_leave(crit);
97	}
98}
99