239 lines
6.9 KiB
C
239 lines
6.9 KiB
C
/***********************************************************************
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* sem.c
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*
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* Copyright (C) 2007 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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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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*
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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
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name Gregory Nutt nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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***********************************************************************/
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#include <sys/types.h>
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#include <stdio.h>
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#include <pthread.h>
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#include <semaphore.h>
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#include <sched.h>
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#include "ostest.h"
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#ifndef NULL
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# define NULL (void*)0
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#endif
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static sem_t sem;
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static void *waiter_func(void *parameter)
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{
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int id = (int)parameter;
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int status;
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int value;
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printf("%s: Thread %d Started\n", __FUNCTION__, id);
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/* Take the semaphore */
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status = sem_getvalue(&sem, &value);
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if (status < 0)
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{
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printf("%s: ERROR thread %d could not get semaphore value\n", __FUNCTION__, id);
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}
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else
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{
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printf("%s: Thread %d initial semaphore value = %d\n", __FUNCTION__, id, value);
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}
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printf("%s: Thread %d aiting on semaphore\n", __FUNCTION__, id);
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status = sem_wait(&sem);
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if (status != 0)
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{
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printf("%s: ERROR thread %d sem_wait failed\n", __FUNCTION__, id);
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}
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printf("%s: Thread %d awakened\n", __FUNCTION__, id);
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status = sem_getvalue(&sem, &value);
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if (status < 0)
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{
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printf("%s: ERROR thread %d could not get semaphore value\n", __FUNCTION__, id);
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}
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else
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{
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printf("%s: Thread %d new semaphore value = %d\n", __FUNCTION__, id, value);
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}
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printf("%s: Thread %d done\n", __FUNCTION__, id);
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return NULL;
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}
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static void *poster_func(void *parameter)
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{
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int id = (int)parameter;
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int status;
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int value;
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printf("%s: Thread %d started\n", __FUNCTION__, id);
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/* Take the semaphore */
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do
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{
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status = sem_getvalue(&sem, &value);
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if (status < 0)
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{
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printf("%s: ERROR thread %d could not get semaphore value\n", __FUNCTION__, id);
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}
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else
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{
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printf("%s: Thread %d semaphore value = %d\n", __FUNCTION__, id, value);
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}
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if (value < 0)
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{
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printf("%s: Thread %d posting semaphore\n", __FUNCTION__, id);
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status = sem_post(&sem);
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if (status != 0)
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{
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printf("%s: ERROR thread %d sem_wait failed\n", __FUNCTION__, id);
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}
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pthread_yield();
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status = sem_getvalue(&sem, &value);
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if (status < 0)
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{
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printf("%s: ERROR thread %d could not get semaphore value\n", __FUNCTION__, id);
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}
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else
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{
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printf("%s: Thread %d new semaphore value = %d\n", __FUNCTION__, id, value);
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}
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}
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}
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while (value < 0);
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printf("%s: Thread %d done\n", __FUNCTION__, id);
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return NULL;
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}
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void sem_test(void)
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{
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pthread_t waiter_thread1;
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pthread_t waiter_thread2;
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pthread_t poster_thread;
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struct sched_param sparam;
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int prio_min;
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int prio_max;
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int prio_mid;
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pthread_attr_t attr;
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int status;
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printf("%s: Initializing semaphore to 0\n", __FUNCTION__);
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sem_init(&sem, 0, 0);
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/* Start two waiter thread instances */
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printf("%s: Starting waiter thread 1\n", __FUNCTION__);
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status = pthread_attr_init(&attr);
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if (status != OK)
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{
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printf("%s: pthread_attr_init failed, status=%d\n", __FUNCTION__, status);
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}
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prio_min = sched_get_priority_min(SCHED_FIFO);
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prio_max = sched_get_priority_max(SCHED_FIFO);
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prio_mid = (prio_min + prio_max) / 2;
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sparam.sched_priority = (prio_mid + prio_max) / 2;
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status = pthread_attr_setschedparam(&attr,&sparam);
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if (status != OK)
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{
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printf("%s: pthread_attr_setschedparam failed, status=%d\n", __FUNCTION__, status);
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}
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else
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{
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printf("%s: Set thread 1 priority to %d\n", __FUNCTION__, sparam.sched_priority);
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}
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status = pthread_create(&waiter_thread1, &attr, waiter_func, (void*)1);
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if (status != 0)
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{
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printf("%s: Error in thread 1 creation, status=%d\n", __FUNCTION__, status);
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}
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printf("%s: Starting waiter thread 2\n", __FUNCTION__);
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status = pthread_attr_init(&attr);
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if (status != 0)
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{
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printf("%s: pthread_attr_init failed, status=%d\n", __FUNCTION__, status);
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}
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sparam.sched_priority = prio_mid;
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status = pthread_attr_setschedparam(&attr,&sparam);
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if (status != OK)
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{
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printf("%s: pthread_attr_setschedparam failed, status=%d\n", __FUNCTION__, status);
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}
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else
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{
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printf("%s: Set thread 2 priority to %d\n", __FUNCTION__, sparam.sched_priority);
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}
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status = pthread_create(&waiter_thread2, &attr, waiter_func, (void*)2);
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if (status != 0)
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{
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printf("%s: Error in thread 2 creation, status=%d\n", __FUNCTION__, status);
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}
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printf("%s: Starting poster thread 3\n", __FUNCTION__);
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status = pthread_attr_init(&attr);
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if (status != 0)
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{
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printf("%s: pthread_attr_init failed, status=%d\n", __FUNCTION__, status);
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}
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sparam.sched_priority = (prio_min + prio_mid) / 2;
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status = pthread_attr_setschedparam(&attr,&sparam);
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if (status != OK)
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{
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printf("%s: pthread_attr_setschedparam failed, status=%d\n", __FUNCTION__, status);
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}
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else
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{
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printf("%s: Set thread 3 priority to %d\n", __FUNCTION__, sparam.sched_priority);
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}
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status = pthread_create(&poster_thread, &attr, poster_func, (void*)3);
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if (status != 0)
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{
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printf("%s: Error in thread 3 creation, status=%d\n", __FUNCTION__, status);
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}
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pthread_join(waiter_thread1, NULL);
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pthread_join(waiter_thread2, NULL);
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pthread_join(poster_thread, NULL);
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}
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