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      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 
     40 void
     41 mtx_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 
     52 static inline int
     53 mtx_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 
     64 static inline int
     65 mtx_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 
     88 int
     89 mtx_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 
    106 int
    107 mtx_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 
    118 int
    119 mtx_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 
    135 int
    136 mtx_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 
    151 int
    152 mtx_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