kopia lustrzana https://github.com/espressif/esp-idf
261 wiersze
5.9 KiB
C
261 wiersze
5.9 KiB
C
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/*
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* SPDX-FileCopyrightText: 2021 Espressif Systems (Shanghai) CO LTD
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <time.h>
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#include <errno.h>
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#include <pthread.h>
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#include <string.h>
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#include <stdatomic.h>
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#include "esp_err.h"
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#include "esp_attr.h"
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#include "sys/queue.h"
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#include "freertos/FreeRTOS.h"
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#include "freertos/task.h"
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#include "freertos/semphr.h"
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#include "soc/soc_memory_layout.h"
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#include "pthread_internal.h"
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#include "esp_pthread.h"
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#include "esp_log.h"
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const static char *TAG = "pthread_rw_lock";
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/** pthread rw_mutex FreeRTOS wrapper */
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typedef struct {
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/**
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*
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*/
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pthread_cond_t cv;
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pthread_mutex_t resource_mutex;
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/**
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* Number of current readers holding this lock, negative number means waiting readers
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*/
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int8_t active_readers;
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uint8_t active_writers;
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uint8_t waiting_writers;
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} esp_pthread_rwlock_t;
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#define WRITER_QUEUE_SIZE 4
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#define READER_QUEUE_SIZE 4
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int pthread_rwlock_init (pthread_rwlock_t *rwlock,
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const pthread_rwlockattr_t *attr)
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{
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int result;
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if (!rwlock) {
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return EINVAL;
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}
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if (attr) {
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// TODO: implement attributes in IDF-4284
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return ENOSYS;
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}
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esp_pthread_rwlock_t *esp_rwlock = (esp_pthread_rwlock_t*) calloc(1, sizeof(esp_pthread_rwlock_t));
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if (esp_rwlock == NULL) {
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return ENOMEM;
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}
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result = pthread_mutex_init(&esp_rwlock->resource_mutex, NULL);
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if (result != 0) {
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free(esp_rwlock);
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return ENOMEM;
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}
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result = pthread_cond_init(&esp_rwlock->cv, NULL);
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if (result != 0) {
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pthread_mutex_destroy(&esp_rwlock->resource_mutex);
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free(esp_rwlock);
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return ENOMEM;
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}
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esp_rwlock->active_readers = 0;
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esp_rwlock->active_writers = 0;
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esp_rwlock->waiting_writers = 0;
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*rwlock = (pthread_rwlock_t) esp_rwlock;
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return 0;
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}
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static int pthread_rwlock_init_if_static(pthread_rwlock_t *rwlock)
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{
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int res = 0;
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if ((intptr_t) *rwlock == PTHREAD_RWLOCK_INITIALIZER) {
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portENTER_CRITICAL(&pthread_lazy_init_lock);
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if ((intptr_t) *rwlock == PTHREAD_RWLOCK_INITIALIZER) {
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res = pthread_rwlock_init(rwlock, NULL);
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}
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portEXIT_CRITICAL(&pthread_lazy_init_lock);
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}
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return res;
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}
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int pthread_rwlock_destroy (pthread_rwlock_t *rwlock)
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{
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esp_pthread_rwlock_t *esp_rwlock;
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ESP_LOGV(TAG, "%s %p", __FUNCTION__, rwlock);
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if (!rwlock) {
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return EINVAL;
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}
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if ((intptr_t) *rwlock == PTHREAD_RWLOCK_INITIALIZER) {
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return 0; // Static rwlock was never initialized
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}
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esp_rwlock = (esp_pthread_rwlock_t *)*rwlock;
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if (esp_rwlock == NULL) {
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return EINVAL;
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}
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// TODO: necessary?
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pthread_mutex_lock(&esp_rwlock->resource_mutex);
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if (esp_rwlock->active_readers != 0 || esp_rwlock->active_writers > 0 || esp_rwlock->waiting_writers > 0) {
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pthread_mutex_unlock(&esp_rwlock->resource_mutex);
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return EBUSY;
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}
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// delete whole lock
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pthread_cond_destroy(&esp_rwlock->cv);
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pthread_mutex_unlock(&esp_rwlock->resource_mutex);
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pthread_mutex_destroy(&esp_rwlock->resource_mutex);
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free(esp_rwlock);
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return 0;
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}
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static int checkrw_lock(pthread_rwlock_t *rwlock)
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{
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esp_pthread_rwlock_t *esp_rwlock;
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int res;
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if (rwlock == NULL) {
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return EINVAL;
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}
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res = pthread_rwlock_init_if_static(rwlock);
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if (res != 0) {
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return res;
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}
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esp_rwlock = (esp_pthread_rwlock_t *)*rwlock;
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if (esp_rwlock == NULL) {
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return EINVAL;
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}
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return 0;
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}
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int pthread_rwlock_rdlock (pthread_rwlock_t *rwlock)
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{
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esp_pthread_rwlock_t *esp_rwlock;
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int res;
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res = checkrw_lock(rwlock);
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if (res != 0) {
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return res;
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}
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esp_rwlock = (esp_pthread_rwlock_t *)*rwlock;
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res = pthread_mutex_lock(&esp_rwlock->resource_mutex);
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if (res != 0) {
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return res;
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}
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if (esp_rwlock->active_writers == 0) {
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esp_rwlock->active_readers++;
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} else {
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while (true) {
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pthread_cond_wait(&esp_rwlock->cv, &esp_rwlock->resource_mutex);
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if (esp_rwlock->active_writers == 0 && esp_rwlock->waiting_writers == 0) {
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esp_rwlock->active_readers++;
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break;
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}
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}
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}
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pthread_mutex_unlock(&esp_rwlock->resource_mutex);
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return 0;
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}
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int pthread_rwlock_wrlock(pthread_rwlock_t *rwlock)
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{
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esp_pthread_rwlock_t *esp_rwlock;
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int res;
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res = checkrw_lock(rwlock);
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if (res != 0) {
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return res;
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}
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esp_rwlock = (esp_pthread_rwlock_t *)*rwlock;
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res = pthread_mutex_lock(&esp_rwlock->resource_mutex);
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if (res != 0) {
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return res;
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}
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esp_rwlock->waiting_writers++;
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while (esp_rwlock->active_readers > 0 || esp_rwlock->active_writers > 0) {
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pthread_cond_wait(&esp_rwlock->cv, &esp_rwlock->resource_mutex);
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}
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esp_rwlock->waiting_writers--;
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esp_rwlock->active_writers++;
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pthread_mutex_unlock(&esp_rwlock->resource_mutex);
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return 0;
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}
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int pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
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{
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esp_pthread_rwlock_t *esp_rwlock;
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int res;
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res = checkrw_lock(rwlock);
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if (res != 0) {
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return res;
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}
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esp_rwlock = (esp_pthread_rwlock_t *)*rwlock;
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res = pthread_mutex_lock(&esp_rwlock->resource_mutex);
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if (res != 0) {
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return res;
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}
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assert(!(esp_rwlock->active_readers > 0 && esp_rwlock->active_writers > 0));
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if (esp_rwlock->active_readers > 0) {
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// we are a reader
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esp_rwlock->active_readers--;
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if (esp_rwlock->active_readers == 0) {
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pthread_cond_broadcast(&esp_rwlock->cv);
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}
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} else {
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// we are a writer
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esp_rwlock->active_writers = 0;
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pthread_cond_broadcast(&esp_rwlock->cv);
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}
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pthread_mutex_unlock(&esp_rwlock->resource_mutex);
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return 0;
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}
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/* Hook function to force linking this file */
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void pthread_include_pthread_rwlock_impl(void)
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{
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}
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