/*      $NetBSD: mtx.c,v 1.1 2019/04/24 11:43:19 kamil Exp $    */

/*-
* Copyright (c) 2016 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Kamil Rytarowski.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#include <sys/cdefs.h>
__RCSID("$NetBSD: mtx.c,v 1.1 2019/04/24 11:43:19 kamil Exp $");

#include <assert.h>
#include <errno.h>
#include <pthread.h>
#include <threads.h>

void
mtx_destroy(mtx_t *mtx)
{

       _DIAGASSERT(mtx != NULL);

       /*
        * The cnd_destroy(3) function that conforms to C11 returns no value.
        */
       (void)pthread_mutex_destroy(mtx);
}

static inline int
mtx_init_default(mtx_t *mtx)
{

       _DIAGASSERT(mtx != NULL);

       if (pthread_mutex_init(mtx, NULL) != 0)
               return thrd_error;

       return thrd_success;
}

static inline int
mtx_init_recursive(mtx_t *mtx)
{
       pthread_mutexattr_t attr;

       _DIAGASSERT(mtx != NULL);

       if (pthread_mutexattr_init(&attr) != 0)
               return thrd_error;

       if (pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE) != 0) {
               pthread_mutexattr_destroy(&attr);

               return thrd_error;
       }

       if (pthread_mutex_init(mtx, &attr) == 0)
               return thrd_success;

       pthread_mutexattr_destroy(&attr);

       return thrd_error;
}

int
mtx_init(mtx_t *mtx, int type)
{

       _DIAGASSERT(mtx != NULL);

       switch (type) {
       case mtx_plain:
       case mtx_timed:
               return mtx_init_default(mtx);
       case mtx_plain | mtx_recursive:
       case mtx_timed | mtx_recursive:
               return mtx_init_recursive(mtx);
       default:
               return thrd_error;
       }
}

int
mtx_lock(mtx_t *mtx)
{

       _DIAGASSERT(mtx != NULL);

       if (pthread_mutex_lock(mtx) == 0)
               return thrd_success;

       return thrd_error;
}

int
mtx_timedlock(mtx_t *__restrict mtx, const struct timespec *__restrict ts)
{

       _DIAGASSERT(mtx != NULL);
       _DIAGASSERT(ts != NULL);

       switch(pthread_mutex_timedlock(mtx, ts)) {
       case 0:
               return thrd_success;
       case ETIMEDOUT:
               return thrd_timedout;
       default:
               return thrd_error;
       }
}

int
mtx_trylock(mtx_t *mtx)
{

       _DIAGASSERT(mtx != NULL);

       switch(pthread_mutex_trylock(mtx)) {
       case 0:
               return thrd_success;
       case EBUSY:
               return thrd_busy;
       default:
               return thrd_error;
       }
}

int
mtx_unlock(mtx_t *mtx)
{

       _DIAGASSERT(mtx != NULL);

       if (pthread_mutex_unlock(mtx) == 0)
               return thrd_success;

       return thrd_error;
}