1/*	$NetBSD: mtx.c,v 1.1 2019/04/24 11:43:19 kamil Exp $	*/
2
3/*-
4 * Copyright (c) 2016 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Kamil Rytarowski.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__RCSID("$NetBSD: mtx.c,v 1.1 2019/04/24 11:43:19 kamil Exp $");
34
35#include <assert.h>
36#include <errno.h>
37#include <pthread.h>
38#include <threads.h>
39
40void
41mtx_destroy(mtx_t *mtx)
42{
43
44	_DIAGASSERT(mtx != NULL);
45
46	/*
47	 * The cnd_destroy(3) function that conforms to C11 returns no value.
48	 */
49	(void)pthread_mutex_destroy(mtx);
50}
51
52static inline int
53mtx_init_default(mtx_t *mtx)
54{
55
56	_DIAGASSERT(mtx != NULL);
57
58	if (pthread_mutex_init(mtx, NULL) != 0)
59		return thrd_error;
60
61        return thrd_success;
62}
63
64static inline int
65mtx_init_recursive(mtx_t *mtx)
66{
67	pthread_mutexattr_t attr;
68
69	_DIAGASSERT(mtx != NULL);
70
71	if (pthread_mutexattr_init(&attr) != 0)
72		return thrd_error;
73
74	if (pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE) != 0) {
75		pthread_mutexattr_destroy(&attr);
76
77		return thrd_error;
78	}
79
80	if (pthread_mutex_init(mtx, &attr) == 0)
81		return thrd_success;
82
83	pthread_mutexattr_destroy(&attr);
84
85	return thrd_error;
86}
87
88int
89mtx_init(mtx_t *mtx, int type)
90{
91
92	_DIAGASSERT(mtx != NULL);
93
94	switch (type) {
95	case mtx_plain:
96	case mtx_timed:
97		return mtx_init_default(mtx);
98	case mtx_plain | mtx_recursive:
99	case mtx_timed | mtx_recursive:
100		return mtx_init_recursive(mtx);
101	default:
102		return thrd_error;
103	}
104}
105
106int
107mtx_lock(mtx_t *mtx)
108{
109
110	_DIAGASSERT(mtx != NULL);
111
112	if (pthread_mutex_lock(mtx) == 0)
113		return thrd_success;
114
115	return thrd_error;
116}
117
118int
119mtx_timedlock(mtx_t *__restrict mtx, const struct timespec *__restrict ts)
120{
121
122	_DIAGASSERT(mtx != NULL);
123	_DIAGASSERT(ts != NULL);
124
125	switch(pthread_mutex_timedlock(mtx, ts)) {
126	case 0:
127		return thrd_success;
128	case ETIMEDOUT:
129		return thrd_timedout;
130	default:
131		return thrd_error;
132	}
133}
134
135int
136mtx_trylock(mtx_t *mtx)
137{
138
139	_DIAGASSERT(mtx != NULL);
140
141	switch(pthread_mutex_trylock(mtx)) {
142	case 0:
143		return thrd_success;
144	case EBUSY:
145		return thrd_busy;
146	default:
147		return thrd_error;
148	}
149}
150
151int
152mtx_unlock(mtx_t *mtx)
153{
154
155	_DIAGASSERT(mtx != NULL);
156
157	if (pthread_mutex_unlock(mtx) == 0)
158		return thrd_success;
159
160	return thrd_error;
161}
162