zephyr/lib/posix/pthread_mutex.c

206 lines
3.3 KiB
C

/*
* Copyright (c) 2017 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <kernel.h>
#include <ksched.h>
#include <wait_q.h>
#include <posix/pthread.h>
#define MUTEX_MAX_REC_LOCK 32767
/*
* Default mutex attrs.
*/
static const pthread_mutexattr_t def_attr = {
.type = PTHREAD_MUTEX_DEFAULT,
};
static int acquire_mutex(pthread_mutex_t *m, int timeout)
{
int rc = 0, key = irq_lock();
if (m->lock_count == 0U && m->owner == NULL) {
m->lock_count++;
m->owner = pthread_self();
irq_unlock(key);
return 0;
} else if (m->owner == pthread_self()) {
if (m->type == PTHREAD_MUTEX_RECURSIVE &&
m->lock_count < MUTEX_MAX_REC_LOCK) {
m->lock_count++;
rc = 0;
} else if (m->type == PTHREAD_MUTEX_ERRORCHECK) {
rc = EDEADLK;
} else {
rc = EINVAL;
}
irq_unlock(key);
return rc;
}
if (timeout == K_NO_WAIT) {
irq_unlock(key);
return EINVAL;
}
rc = z_pend_curr_irqlock(key, &m->wait_q, timeout);
if (rc != 0) {
rc = ETIMEDOUT;
}
return rc;
}
/**
* @brief Lock POSIX mutex with non-blocking call.
*
* See IEEE 1003.1
*/
int pthread_mutex_trylock(pthread_mutex_t *m)
{
return acquire_mutex(m, K_NO_WAIT);
}
/**
* @brief Lock POSIX mutex with timeout.
*
*
* See IEEE 1003.1
*/
int pthread_mutex_timedlock(pthread_mutex_t *m,
const struct timespec *to)
{
return acquire_mutex(m, _ts_to_ms(to));
}
/**
* @brief Intialize POSIX mutex.
*
* See IEEE 1003.1
*/
int pthread_mutex_init(pthread_mutex_t *m,
const pthread_mutexattr_t *attr)
{
const pthread_mutexattr_t *mattr;
m->owner = NULL;
m->lock_count = 0U;
mattr = (attr == NULL) ? &def_attr : attr;
m->type = mattr->type;
z_waitq_init(&m->wait_q);
return 0;
}
/**
* @brief Lock POSIX mutex with blocking call.
*
* See IEEE 1003.1
*/
int pthread_mutex_lock(pthread_mutex_t *m)
{
return acquire_mutex(m, K_FOREVER);
}
/**
* @brief Unlock POSIX mutex.
*
* See IEEE 1003.1
*/
int pthread_mutex_unlock(pthread_mutex_t *m)
{
unsigned int key = irq_lock();
k_tid_t thread;
if (m->owner != pthread_self()) {
irq_unlock(key);
return EPERM;
}
if (m->lock_count == 0U) {
irq_unlock(key);
return EINVAL;
}
m->lock_count--;
if (m->lock_count == 0U) {
thread = z_unpend_first_thread(&m->wait_q);
if (thread) {
m->owner = (pthread_t)thread;
m->lock_count++;
z_ready_thread(thread);
z_set_thread_return_value(thread, 0);
z_reschedule_irqlock(key);
return 0;
}
m->owner = NULL;
}
irq_unlock(key);
return 0;
}
/**
* @brief Destroy POSIX mutex.
*
* See IEEE 1003.1
*/
int pthread_mutex_destroy(pthread_mutex_t *m)
{
ARG_UNUSED(m);
return 0;
}
/**
* @brief Read protocol attribute for mutex.
*
* See IEEE 1003.1
*/
int pthread_mutexattr_getprotocol(const pthread_mutexattr_t *attr,
int *protocol)
{
*protocol = PTHREAD_PRIO_NONE;
return 0;
}
/**
* @brief Read type attribute for mutex.
*
* See IEEE 1003.1
*/
int pthread_mutexattr_gettype(const pthread_mutexattr_t *attr, int *type)
{
*type = attr->type;
return 0;
}
/**
* @brief Set type attribute for mutex.
*
* See IEEE 1003.1
*/
int pthread_mutexattr_settype(pthread_mutexattr_t *attr, int type)
{
int retc = EINVAL;
if ((type == PTHREAD_MUTEX_NORMAL) ||
(type == PTHREAD_MUTEX_RECURSIVE) ||
(type == PTHREAD_MUTEX_ERRORCHECK)) {
attr->type = type;
retc = 0;
}
return retc;
}