zephyr/lib/posix/semaphore.c

151 lines
2.3 KiB
C

/*
* Copyright (c) 2018 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <errno.h>
#include <zephyr/posix/pthread.h>
/**
* @brief Destroy semaphore.
*
* see IEEE 1003.1
*/
int sem_destroy(sem_t *semaphore)
{
if (semaphore == NULL) {
errno = EINVAL;
return -1;
}
if (k_sem_count_get(semaphore)) {
errno = EBUSY;
return -1;
}
k_sem_reset(semaphore);
return 0;
}
/**
* @brief Get value of semaphore.
*
* See IEEE 1003.1
*/
int sem_getvalue(sem_t *semaphore, int *value)
{
if (semaphore == NULL) {
errno = EINVAL;
return -1;
}
*value = (int) k_sem_count_get(semaphore);
return 0;
}
/**
* @brief Initialize semaphore.
*
* See IEEE 1003.1
*/
int sem_init(sem_t *semaphore, int pshared, unsigned int value)
{
if (value > CONFIG_SEM_VALUE_MAX) {
errno = EINVAL;
return -1;
}
/*
* Zephyr has no concept of process, so only thread shared
* semaphore makes sense in here.
*/
__ASSERT(pshared == 0, "pshared should be 0");
k_sem_init(semaphore, value, CONFIG_SEM_VALUE_MAX);
return 0;
}
/**
* @brief Unlock a semaphore.
*
* See IEEE 1003.1
*/
int sem_post(sem_t *semaphore)
{
if (semaphore == NULL) {
errno = EINVAL;
return -1;
}
k_sem_give(semaphore);
return 0;
}
/**
* @brief Try time limited locking a semaphore.
*
* See IEEE 1003.1
*/
int sem_timedwait(sem_t *semaphore, struct timespec *abstime)
{
int32_t timeout;
struct timespec current;
int64_t current_ms, abstime_ms;
__ASSERT(abstime, "abstime pointer NULL");
if ((abstime->tv_sec < 0) || (abstime->tv_nsec >= NSEC_PER_SEC)) {
errno = EINVAL;
return -1;
}
if (clock_gettime(CLOCK_REALTIME, &current) < 0) {
return -1;
}
abstime_ms = (int64_t)_ts_to_ms(abstime);
current_ms = (int64_t)_ts_to_ms(&current);
if (abstime_ms <= current_ms) {
timeout = 0;
} else {
timeout = (int32_t)(abstime_ms - current_ms);
}
if (k_sem_take(semaphore, K_MSEC(timeout))) {
errno = ETIMEDOUT;
return -1;
}
return 0;
}
/**
* @brief Lock a semaphore if not taken.
*
* See IEEE 1003.1
*/
int sem_trywait(sem_t *semaphore)
{
if (k_sem_take(semaphore, K_NO_WAIT) == -EBUSY) {
errno = EAGAIN;
return -1;
} else {
return 0;
}
}
/**
* @brief Lock a semaphore.
*
* See IEEE 1003.1
*/
int sem_wait(sem_t *semaphore)
{
/* With K_FOREVER, may return only success. */
(void)k_sem_take(semaphore, K_FOREVER);
return 0;
}