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LibPthread: Implement semaphore functions

This commit is contained in:
Gunnar Beutner 2021-04-14 04:29:39 +02:00 committed by Andreas Kling
parent f2ff8f2658
commit ea6d0aa1d4
4 changed files with 73 additions and 15 deletions

View file

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/*
* Copyright (c) 2021, the SerenityOS developers.
* All rights reserved.
*
* 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 COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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 <AK/Assertions.h>
#include <errno.h>
#include <semaphore.h>
int sem_close(sem_t*)
{
errno = ENOSYS;
return -1;
}
int sem_destroy(sem_t* sem)
{
pthread_mutex_destroy(&sem->mtx);
pthread_cond_destroy(&sem->cv);
return 0;
}
int sem_getvalue(sem_t*, int*)
{
VERIFY_NOT_REACHED();
}
int sem_init(sem_t* sem, int shared, unsigned int value)
{
if (shared)
return ENOSYS;
if (pthread_mutex_init(&sem->mtx, nullptr) != 0)
return -1;
if (pthread_cond_init(&sem->cv, nullptr) != 0)
return -1;
sem->value = value;
return 0;
}
sem_t* sem_open(const char*, int, ...)
{
errno = ENOSYS;
return nullptr;
}
int sem_post(sem_t* sem)
{
sem->value++;
pthread_cond_signal(&sem->cv);
pthread_mutex_unlock(&sem->mtx);
return 0;
}
int sem_trywait(sem_t* sem)
{
if (pthread_mutex_lock(&sem->mtx) != 0)
return -1;
if (sem->value == 0) {
pthread_mutex_unlock(&sem->mtx);
errno = EAGAIN;
return -1;
}
sem->value--;
return 0;
}
int sem_unlink(const char*)
{
return ENOSYS;
}
int sem_wait(sem_t* sem)
{
if (pthread_mutex_lock(&sem->mtx) != 0)
return -1;
while (sem->value == 0) {
if (pthread_cond_wait(&sem->cv, &sem->mtx) != 0) {
pthread_mutex_unlock(&sem->mtx);
return -1;
}
}
sem->value--;
return 0;
}