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372 lines
9.4 KiB
C
372 lines
9.4 KiB
C
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/* ==== mutex.c ==============================================================
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* Copyright (c) 1993, 1994 by Chris Provenzano, proven@mit.edu
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Chris Provenzano.
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* 4. The name of Chris Provenzano may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY CHRIS PROVENZANO ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL CHRIS PROVENZANO BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* Description : Mutex functions.
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*
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* 1.00 93/07/19 proven
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* -Started coding this file.
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*/
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#ifndef lint
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static const char rcsid[] = "$Id$";
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#endif
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#include <pthread.h>
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#include <stdlib.h>
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#include <errno.h>
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/* ==========================================================================
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* pthread_mutex_is_debug()
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*
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* Check that mutex is a debug mutex and if so returns entry number into
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* array of debug mutexes.
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*/
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static int pthread_mutex_debug_count = 0;
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static pthread_mutex_t ** pthread_mutex_debug_ptrs = NULL;
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static inline int pthread_mutex_is_debug(pthread_mutex_t * mutex)
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{
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int i;
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for (i = 0; i < pthread_mutex_debug_count; i++) {
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if (pthread_mutex_debug_ptrs[i] == mutex) {
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return(i);
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}
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}
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return(NOTOK);
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}
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/* ==========================================================================
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* pthread_mutex_init()
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*
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* In this implementation I don't need to allocate memory.
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* ENOMEM, EAGAIN should never be returned. Arch that have
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* weird constraints may need special coding.
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*/
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int pthread_mutex_init(pthread_mutex_t *mutex,
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const pthread_mutexattr_t *mutex_attr)
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{
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enum pthread_mutextype type;
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/* Only check if attr specifies some mutex type other than fast */
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if ((mutex_attr) && (mutex_attr->m_type != MUTEX_TYPE_FAST)) {
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if (mutex_attr->m_type >= MUTEX_TYPE_MAX) {
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return(EINVAL);
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}
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type = mutex_attr->m_type;
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} else {
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type = MUTEX_TYPE_FAST;
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}
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mutex->m_flags = 0;
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pthread_sched_prevent();
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switch(type) {
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case MUTEX_TYPE_FAST:
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break;
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case MUTEX_TYPE_STATIC_FAST:
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pthread_sched_resume();
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return(EINVAL);
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break;
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case MUTEX_TYPE_COUNTING_FAST:
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mutex->m_data.m_count = 0;
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break;
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case MUTEX_TYPE_DEBUG:
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if (pthread_mutex_is_debug(mutex) == NOTOK) {
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pthread_mutex_t ** new;
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if ((new = (pthread_mutex_t **)realloc(pthread_mutex_debug_ptrs,
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(pthread_mutex_debug_count + 1) * (sizeof(void *)))) == NULL) {
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pthread_sched_resume();
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return(ENOMEM);
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}
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pthread_mutex_debug_ptrs = new;
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pthread_mutex_debug_ptrs[pthread_mutex_debug_count++] = mutex;
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} else {
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pthread_sched_resume();
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return(EBUSY);
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}
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break;
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default:
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pthread_sched_resume();
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return(EINVAL);
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break;
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}
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/* Set all other paramaters */
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pthread_queue_init(&mutex->m_queue);
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mutex->m_flags |= MUTEX_FLAGS_INITED;
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mutex->m_owner = NULL;
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mutex->m_type = type;
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pthread_sched_resume();
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return(OK);
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}
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/* ==========================================================================
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* pthread_mutex_destroy()
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*/
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int pthread_mutex_destroy(pthread_mutex_t *mutex)
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{
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int i;
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pthread_sched_prevent();
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/* Only check if mutex is of type other than fast */
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switch(mutex->m_type) {
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case MUTEX_TYPE_FAST:
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break;
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case MUTEX_TYPE_STATIC_FAST:
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pthread_sched_resume();
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return(EINVAL);
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break;
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case MUTEX_TYPE_COUNTING_FAST:
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mutex->m_data.m_count = 0;
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break;
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case MUTEX_TYPE_DEBUG:
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if ((i = pthread_mutex_is_debug(mutex)) == NOTOK) {
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pthread_sched_resume();
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return(EINVAL);
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}
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if (mutex->m_owner) {
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pthread_sched_resume();
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return(EBUSY);
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}
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/* Remove the mutex from the list of debug mutexes */
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pthread_mutex_debug_ptrs[i] =
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pthread_mutex_debug_ptrs[--pthread_mutex_debug_count];
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pthread_mutex_debug_ptrs[pthread_mutex_debug_count] = NULL;
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break;
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default:
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pthread_sched_resume();
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return(EINVAL);
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break;
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}
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/* Cleanup mutex, others might want to use it. */
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pthread_queue_init(&mutex->m_queue);
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mutex->m_owner = NULL;
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mutex->m_flags = 0;
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pthread_sched_resume();
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return(OK);
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}
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/* ==========================================================================
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* pthread_mutex_trylock()
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*/
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int pthread_mutex_trylock(pthread_mutex_t *mutex)
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{
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int rval;
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pthread_sched_prevent();
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switch (mutex->m_type) {
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/*
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* Fast mutexes do not check for any error conditions.
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*/
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case MUTEX_TYPE_FAST:
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case MUTEX_TYPE_STATIC_FAST:
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if (!mutex->m_owner) {
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mutex->m_owner = pthread_run;
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rval = OK;
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} else {
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rval = EBUSY;
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}
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break;
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case MUTEX_TYPE_COUNTING_FAST:
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if (mutex->m_owner) {
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if (mutex->m_owner == pthread_run) {
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mutex->m_data.m_count++;
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rval = OK;
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} else {
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rval = EBUSY;
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}
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} else {
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mutex->m_owner = pthread_run;
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rval = OK;
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}
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break;
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case MUTEX_TYPE_DEBUG:
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if (pthread_mutex_is_debug(mutex) != NOTOK) {
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if (!mutex->m_owner) {
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mutex->m_owner = pthread_run;
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rval = OK;
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} else {
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rval = EBUSY;
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}
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} else {
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rval = EINVAL;
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}
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break;
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default:
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rval = EINVAL;
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break;
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}
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pthread_sched_resume();
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return(rval);
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}
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/* ==========================================================================
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* pthread_mutex_lock()
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*/
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int pthread_mutex_lock(pthread_mutex_t *mutex)
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{
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int rval;
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pthread_sched_prevent();
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switch (mutex->m_type) {
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/*
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* Fast mutexes do not check for any error conditions.
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*/
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case MUTEX_TYPE_FAST:
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case MUTEX_TYPE_STATIC_FAST:
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if (mutex->m_owner) {
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pthread_queue_enq(&mutex->m_queue, pthread_run);
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/* Reschedule will unlock scheduler */
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pthread_resched_resume(PS_MUTEX_WAIT);
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return(OK);
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}
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mutex->m_owner = pthread_run;
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rval = OK;
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break;
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case MUTEX_TYPE_COUNTING_FAST:
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if (mutex->m_owner) {
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if (mutex->m_owner != pthread_run) {
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pthread_queue_enq(&mutex->m_queue, pthread_run);
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/* Reschedule will unlock scheduler */
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pthread_resched_resume(PS_MUTEX_WAIT);
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return(OK);
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} else {
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mutex->m_data.m_count++;
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}
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} else {
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mutex->m_owner = pthread_run;
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}
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rval = OK;
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break;
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case MUTEX_TYPE_DEBUG:
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if (pthread_mutex_is_debug(mutex) != NOTOK) {
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if (mutex->m_owner) {
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if (mutex->m_owner != pthread_run) {
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pthread_queue_enq(&mutex->m_queue, pthread_run);
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/* Reschedule will unlock pthread_run */
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pthread_resched_resume(PS_MUTEX_WAIT);
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if (mutex->m_owner != pthread_run) {
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PANIC();
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}
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return(OK);
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}
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rval = EDEADLK;
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break;
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}
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mutex->m_owner = pthread_run;
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rval = OK;
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break;
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}
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rval = EINVAL;
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break;
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default:
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rval = EINVAL;
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break;
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}
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pthread_sched_resume();
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return(rval);
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}
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/* ==========================================================================
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* pthread_mutex_unlock()
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*/
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int pthread_mutex_unlock(pthread_mutex_t *mutex)
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{
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struct pthread *pthread;
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int rval;
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pthread_sched_prevent();
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switch (mutex->m_type) {
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/*
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* Fast mutexes do not check for any error conditions.
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*/
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case MUTEX_TYPE_FAST:
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case MUTEX_TYPE_STATIC_FAST:
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if (mutex->m_owner = pthread_queue_deq(&mutex->m_queue)) {
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/* Reschedule will unlock scheduler */
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pthread_sched_other_resume(mutex->m_owner);
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return(OK);
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}
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rval = OK;
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break;
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case MUTEX_TYPE_COUNTING_FAST:
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if (mutex->m_data.m_count) {
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mutex->m_data.m_count--;
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rval = OK;
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break;
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}
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if (mutex->m_owner = pthread_queue_deq(&mutex->m_queue)) {
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/* Reschedule will unlock scheduler */
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pthread_sched_other_resume(mutex->m_owner);
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return(OK);
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}
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rval = OK;
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break;
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case MUTEX_TYPE_DEBUG:
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if (pthread_mutex_is_debug(mutex) != NOTOK) {
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if (mutex->m_owner == pthread_run) {
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if (mutex->m_owner = pthread_queue_deq(&mutex->m_queue)) {
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/* Reschedule will unlock scheduler */
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pthread_sched_other_resume(mutex->m_owner);
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return(OK);
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}
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rval = OK;
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} else {
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rval = EPERM;
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}
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} else {
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rval = EINVAL;
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}
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break;
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default:
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rval = EINVAL;
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break;
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}
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pthread_sched_resume();
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return(rval);
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}
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