OVMS3-idf/components/pthread/pthread_cond_var.c
Ivan Grokhotkov 661769527c pthread: force linking pthread implementation from IDF
Force linking pthread implementation from IDF, instead of the weak
functions provided by gthread library. Previously this would either
work or not depending on the linking order.

Thanks @bpietsch for suggesting the fix.

Closes https://github.com/espressif/esp-idf/issues/3709
2019-07-29 04:43:49 +02:00

205 lines
5.5 KiB
C

// Copyright 2017 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// This is a simple implementation of pthread condition variables. In essence,
// the waiter creates its own semaphore to wait on and pushes it in the cond var
// specific list. Upon notify and broadcast, all the waiters for the given cond
// var are woken up.
#include <errno.h>
#include <pthread.h>
#include <string.h>
#include "esp_err.h"
#include "esp_attr.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/semphr.h"
#include "freertos/list.h"
#include <sys/queue.h>
#include <sys/time.h>
#define LOG_LOCAL_LEVEL CONFIG_LOG_DEFAULT_LEVEL
#include "esp_log.h"
const static char *TAG = "esp_pthread";
typedef struct esp_pthread_cond_waiter {
SemaphoreHandle_t wait_sem; ///< task specific semaphore to wait on
TAILQ_ENTRY(esp_pthread_cond_waiter) link; ///< stash on the list of semaphores to be notified
} esp_pthread_cond_waiter_t;
typedef struct esp_pthread_cond {
_lock_t lock; ///< lock that protects the list of semaphores
TAILQ_HEAD(, esp_pthread_cond_waiter) waiter_list; ///< head of the list of semaphores
} esp_pthread_cond_t;
int pthread_cond_signal(pthread_cond_t *cv)
{
if (cv == NULL || *cv == (pthread_cond_t) 0) {
return EINVAL;
}
esp_pthread_cond_t *cond = (esp_pthread_cond_t *) *cv;
_lock_acquire_recursive(&cond->lock);
esp_pthread_cond_waiter_t *entry;
entry = TAILQ_FIRST(&cond->waiter_list);
if (entry) {
xSemaphoreGive(entry->wait_sem);
}
_lock_release_recursive(&cond->lock);
return 0;
}
int pthread_cond_broadcast(pthread_cond_t *cv)
{
if (cv == NULL || *cv == (pthread_cond_t) 0) {
return EINVAL;
}
esp_pthread_cond_t *cond = (esp_pthread_cond_t *) *cv;
_lock_acquire_recursive(&cond->lock);
esp_pthread_cond_waiter_t *entry;
TAILQ_FOREACH(entry, &cond->waiter_list, link) {
xSemaphoreGive(entry->wait_sem);
}
_lock_release_recursive(&cond->lock);
return 0;
}
int pthread_cond_wait(pthread_cond_t *cv, pthread_mutex_t *mut)
{
return pthread_cond_timedwait(cv, mut, NULL);
}
int pthread_cond_timedwait(pthread_cond_t *cv, pthread_mutex_t *mut, const struct timespec *to)
{
int ret;
TickType_t timeout_ticks;
if (cv == NULL || *cv == (pthread_cond_t) 0) {
return EINVAL;
}
esp_pthread_cond_t *cond = (esp_pthread_cond_t *) *cv;
if (to == NULL) {
timeout_ticks = portMAX_DELAY;
} else {
struct timeval abs_time, cur_time, diff_time;
long timeout_msec;
gettimeofday(&cur_time, NULL);
abs_time.tv_sec = to->tv_sec;
abs_time.tv_usec = to->tv_nsec / 1000;
if (timercmp(&abs_time, &cur_time, <)) {
/* As per the pthread spec, if the time has already
* passed, no sleep is required.
*/
timeout_msec = 0;
} else {
timersub(&abs_time, &cur_time, &diff_time);
timeout_msec = (diff_time.tv_sec * 1000) + (diff_time.tv_usec / 1000);
}
if (timeout_msec <= 0) {
return ETIMEDOUT;
}
timeout_ticks = timeout_msec / portTICK_PERIOD_MS;
}
esp_pthread_cond_waiter_t w;
w.wait_sem = xSemaphoreCreateCounting(1, 0); /* First get will block */
_lock_acquire_recursive(&cond->lock);
TAILQ_INSERT_TAIL(&cond->waiter_list, &w, link);
_lock_release_recursive(&cond->lock);
pthread_mutex_unlock(mut);
if (xSemaphoreTake(w.wait_sem, timeout_ticks) == pdTRUE) {
ret = 0;
} else {
ret = ETIMEDOUT;
}
_lock_acquire_recursive(&cond->lock);
TAILQ_REMOVE(&cond->waiter_list, &w, link);
_lock_release_recursive(&cond->lock);
vSemaphoreDelete(w.wait_sem);
pthread_mutex_lock(mut);
return ret;
}
int pthread_condattr_init(pthread_condattr_t *attr)
{
ESP_LOGV(TAG, "%s not yet implemented (%p)", __FUNCTION__, attr);
return ENOSYS;
}
int pthread_cond_init(pthread_cond_t *cv, const pthread_condattr_t *att)
{
(void) att; /* Unused argument as of now */
if (cv == NULL) {
return EINVAL;
}
esp_pthread_cond_t *cond = (esp_pthread_cond_t *) calloc(1, sizeof(esp_pthread_cond_t));
if (cond == NULL) {
return ENOMEM;
}
_lock_init_recursive(&cond->lock);
TAILQ_INIT(&cond->waiter_list);
*cv = (pthread_cond_t) cond;
return 0;
}
int pthread_cond_destroy(pthread_cond_t *cv)
{
int ret = 0;
if (cv == NULL || *cv == (pthread_cond_t) 0) {
return EINVAL;
}
esp_pthread_cond_t *cond = (esp_pthread_cond_t *) *cv;
_lock_acquire_recursive(&cond->lock);
if (!TAILQ_EMPTY(&cond->waiter_list)) {
ret = EBUSY;
}
_lock_release_recursive(&cond->lock);
if (ret == 0) {
*cv = (pthread_cond_t) 0;
_lock_close_recursive(&cond->lock);
free(cond);
}
return ret;
}
/* Hook function to force linking this file */
void pthread_include_pthread_cond_var_impl()
{
}