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OVMS3-idf/components/pthread/pthread.c
Kedar Sovani 07992b08e8 [pthread] Perform init_routine execution outside of the mutex 
The mutex is common across all the threads. It needn't be held across
the init_routine() call as long as the 'once' behaviour is guaranteed

Saw a deadlock case, where init_routine of one thread was waiting for
the completion of init_routine in another thread.

t2: wait for command
t1: pthread_once:
         lock once_mux
         init_routine:
               inform thread t2
               wait for signal from t2
t2: received command
         pthread_once
             lock once_mux (already held by t1)
---- Deadlock ----
2017-10-25 13:57:39 +05:30

554 lines
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// 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 module implements pthread API on top of FreeRTOS. API is implemented to the level allowing
// libstdcxx threading framework to operate correctly. So not all original pthread routines are supported.
// Moreover some implemened functions do not provide full functionality, e.g. pthread_create does not support
// thread's attributes customization (prio, stack size and so on). So if you are not satisfied with default
// behavior use native FreeRTOS API.
//
#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 "pthread_internal.h"
#define LOG_LOCAL_LEVEL CONFIG_LOG_DEFAULT_LEVEL
#include "esp_log.h"
const static char *TAG = "esp_pthread";
/** task state */
enum esp_pthread_task_state {
PTHREAD_TASK_STATE_RUN,
PTHREAD_TASK_STATE_EXIT
};
/** pthread thread FreeRTOS wrapper */
typedef struct {
ListItem_t list_item; ///< Tasks list node struct. FreeRTOS task handle is kept as list_item.xItemValue
TaskHandle_t join_task; ///< Handle of the task waiting to join
enum esp_pthread_task_state state; ///< pthread task state
bool detached; ///< True if pthread is detached
} esp_pthread_t;
/** pthread wrapper task arg */
typedef struct {
void *(*func)(void *); ///< user task entry
void *arg; ///< user task argument
} esp_pthread_task_arg_t;
/** pthread mutex FreeRTOS wrapper */
typedef struct {
ListItem_t list_item; ///< mutexes list node struct
SemaphoreHandle_t sem; ///< Handle of the task waiting to join
int type; ///< Mutex type. Currently supported PTHREAD_MUTEX_NORMAL and PTHREAD_MUTEX_RECURSIVE
} esp_pthread_mutex_t;
static SemaphoreHandle_t s_once_mux = NULL;
static SemaphoreHandle_t s_threads_mux = NULL;
static portMUX_TYPE s_mutex_init_lock = portMUX_INITIALIZER_UNLOCKED;
static List_t s_threads_list;
static int IRAM_ATTR pthread_mutex_lock_internal(esp_pthread_mutex_t *mux, TickType_t tmo);
esp_err_t esp_pthread_init(void)
{
vListInitialise((List_t *)&s_threads_list);
s_once_mux = xSemaphoreCreateRecursiveMutex();
if (s_once_mux == NULL) {
return ESP_ERR_NO_MEM;
}
s_threads_mux = xSemaphoreCreateMutex();
if (s_threads_mux == NULL) {
vSemaphoreDelete(s_once_mux);
return ESP_ERR_NO_MEM;
}
return ESP_OK;
}
static void *pthread_find_list_item(void *(*item_check)(ListItem_t *, void *arg), void *check_arg)
{
ListItem_t const *list_end = listGET_END_MARKER(&s_threads_list);
ListItem_t *list_item = listGET_HEAD_ENTRY(&s_threads_list);
while (list_item != list_end) {
void *val = item_check(list_item, check_arg);
if (val) {
return val;
}
list_item = listGET_NEXT(list_item);
}
return NULL;
}
static void *pthread_get_handle_by_desc(ListItem_t *item, void *arg)
{
esp_pthread_t *pthread = listGET_LIST_ITEM_OWNER(item);
if (pthread == arg) {
return (void *)listGET_LIST_ITEM_VALUE(item);
}
return NULL;
}
static inline TaskHandle_t pthread_find_handle(pthread_t thread)
{
return pthread_find_list_item(pthread_get_handle_by_desc, (void *)thread);
}
static void *pthread_get_desc_by_handle(ListItem_t *item, void *arg)
{
TaskHandle_t task_handle = arg;
TaskHandle_t cur_handle = (TaskHandle_t)listGET_LIST_ITEM_VALUE(item);
if (task_handle == cur_handle) {
return (esp_pthread_t *)listGET_LIST_ITEM_OWNER(item);
}
return NULL;
}
static esp_pthread_t *pthread_find(TaskHandle_t task_handle)
{
return pthread_find_list_item(pthread_get_desc_by_handle, task_handle);
}
static void pthread_delete(esp_pthread_t *pthread)
{
uxListRemove(&pthread->list_item);
free(pthread);
}
static void pthread_task_func(void *arg)
{
esp_pthread_task_arg_t *task_arg = (esp_pthread_task_arg_t *)arg;
ESP_LOGV(TAG, "%s ENTER %p", __FUNCTION__, task_arg->func);
// wait for start
xTaskNotifyWait(0, 0, NULL, portMAX_DELAY);
ESP_LOGV(TAG, "%s START %p", __FUNCTION__, task_arg->func);
task_arg->func(task_arg->arg);
ESP_LOGV(TAG, "%s END %p", __FUNCTION__, task_arg->func);
free(task_arg);
/* preemptively clean up thread local storage, rather than
waiting for the idle task to clean up the thread */
pthread_internal_local_storage_destructor_callback();
if (xSemaphoreTake(s_threads_mux, portMAX_DELAY) != pdTRUE) {
assert(false && "Failed to lock threads list!");
}
esp_pthread_t *pthread = pthread_find(xTaskGetCurrentTaskHandle());
if (!pthread) {
assert(false && "Failed to find pthread for current task!");
}
if (pthread->detached) {
// auto-free for detached threads
pthread_delete(pthread);
} else {
// Remove from list, it indicates that task has exited
if (pthread->join_task) {
// notify join
xTaskNotify(pthread->join_task, 0, eNoAction);
} else {
pthread->state = PTHREAD_TASK_STATE_EXIT;
}
}
xSemaphoreGive(s_threads_mux);
vTaskDelete(NULL);
ESP_LOGV(TAG, "%s EXIT", __FUNCTION__);
}
int pthread_create(pthread_t *thread, const pthread_attr_t *attr,
void *(*start_routine) (void *), void *arg)
{
TaskHandle_t xHandle = NULL;
ESP_LOGV(TAG, "%s", __FUNCTION__);
if (attr) {
ESP_LOGE(TAG, "%s: attrs not supported!", __FUNCTION__);
return ENOSYS;
}
esp_pthread_task_arg_t *task_arg = malloc(sizeof(esp_pthread_task_arg_t));
if (task_arg == NULL) {
ESP_LOGE(TAG, "Failed to allocate task args!");
return ENOMEM;
}
memset(task_arg, 0, sizeof(esp_pthread_task_arg_t));
esp_pthread_t *pthread = malloc(sizeof(esp_pthread_t));
if (pthread == NULL) {
ESP_LOGE(TAG, "Failed to allocate pthread data!");
free(task_arg);
return ENOMEM;
}
memset(pthread, 0, sizeof(esp_pthread_t));
task_arg->func = start_routine;
task_arg->arg = arg;
BaseType_t res = xTaskCreate(&pthread_task_func, "pthread", CONFIG_ESP32_PTHREAD_TASK_STACK_SIZE_DEFAULT,
task_arg, CONFIG_ESP32_PTHREAD_TASK_PRIO_DEFAULT, &xHandle);
if(res != pdPASS) {
ESP_LOGE(TAG, "Failed to create task!");
free(pthread);
free(task_arg);
if (res == errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY) {
return ENOMEM;
} else {
return EAGAIN;
}
}
vListInitialiseItem((ListItem_t *)&pthread->list_item);
listSET_LIST_ITEM_OWNER((ListItem_t *)&pthread->list_item, pthread);
listSET_LIST_ITEM_VALUE((ListItem_t *)&pthread->list_item, (TickType_t)xHandle);
if (xSemaphoreTake(s_threads_mux, portMAX_DELAY) != pdTRUE) {
assert(false && "Failed to lock threads list!");
}
vListInsertEnd((List_t *)&s_threads_list, (ListItem_t *)&pthread->list_item);
xSemaphoreGive(s_threads_mux);
// start task
xTaskNotify(xHandle, 0, eNoAction);
*thread = (pthread_t)pthread; // pointer value fit into pthread_t (uint32_t)
ESP_LOGV(TAG, "Created task %x", (uint32_t)xHandle);
return 0;
}
int pthread_join(pthread_t thread, void **retval)
{
esp_pthread_t *pthread = (esp_pthread_t *)thread;
int ret = 0;
bool wait = false;
ESP_LOGV(TAG, "%s %p", __FUNCTION__, pthread);
// find task
if (xSemaphoreTake(s_threads_mux, portMAX_DELAY) != pdTRUE) {
assert(false && "Failed to lock threads list!");
}
TaskHandle_t handle = pthread_find_handle(thread);
if (!handle) {
// not found
ret = ESRCH;
} else if (pthread->join_task) {
// already have waiting task to join
ret = EINVAL;
} else if (handle == xTaskGetCurrentTaskHandle()) {
// join to self not allowed
ret = EDEADLK;
} else {
esp_pthread_t *cur_pthread = pthread_find(xTaskGetCurrentTaskHandle());
if (cur_pthread && cur_pthread->join_task == handle) {
// join to each other not allowed
ret = EDEADLK;
} else {
if (pthread->state == PTHREAD_TASK_STATE_RUN) {
pthread->join_task = xTaskGetCurrentTaskHandle();
wait = true;
} else {
pthread_delete(pthread);
}
}
}
xSemaphoreGive(s_threads_mux);
if (ret == 0 && wait) {
xTaskNotifyWait(0, 0, NULL, portMAX_DELAY);
if (xSemaphoreTake(s_threads_mux, portMAX_DELAY) != pdTRUE) {
assert(false && "Failed to lock threads list!");
}
pthread_delete(pthread);
xSemaphoreGive(s_threads_mux);
}
if (retval) {
*retval = 0; // no exit code in FreeRTOS
}
ESP_LOGV(TAG, "%s %p EXIT %d", __FUNCTION__, pthread, ret);
return ret;
}
int pthread_detach(pthread_t thread)
{
esp_pthread_t *pthread = (esp_pthread_t *)thread;
int ret = 0;
if (xSemaphoreTake(s_threads_mux, portMAX_DELAY) != pdTRUE) {
assert(false && "Failed to lock threads list!");
}
TaskHandle_t handle = pthread_find_handle(thread);
if (!handle) {
ret = ESRCH;
} else {
pthread->detached = true;
}
xSemaphoreGive(s_threads_mux);
ESP_LOGV(TAG, "%s %p EXIT %d", __FUNCTION__, pthread, ret);
return ret;
}
int pthread_cancel(pthread_t thread)
{
ESP_LOGE(TAG, "%s: not supported!", __FUNCTION__);
return ENOSYS;
}
int sched_yield( void )
{
vTaskDelay(0);
return 0;
}
pthread_t pthread_self(void)
{
if (xSemaphoreTake(s_threads_mux, portMAX_DELAY) != pdTRUE) {
assert(false && "Failed to lock threads list!");
}
esp_pthread_t *pthread = pthread_find(xTaskGetCurrentTaskHandle());
if (!pthread) {
assert(false && "Failed to find current thread ID!");
}
xSemaphoreGive(s_threads_mux);
return (pthread_t)pthread;
}
int pthread_equal(pthread_t t1, pthread_t t2)
{
return t1 == t2 ? 1 : 0;
}
/***************** ONCE ******************/
int pthread_once(pthread_once_t *once_control, void (*init_routine)(void))
{
if (once_control == NULL || init_routine == NULL || !once_control->is_initialized) {
ESP_LOGE(TAG, "%s: Invalid args!", __FUNCTION__);
return EINVAL;
}
TaskHandle_t cur_task = xTaskGetCurrentTaskHandle();
uint8_t do_execute = 0;
// do not take mutex if OS is not running yet
if (xTaskGetSchedulerState() == taskSCHEDULER_NOT_STARTED ||
// init_routine can call pthread_once for another objects, so use recursive mutex
// FIXME: behaviour is undefined if init_routine calls pthread_once for the same object in the current context
!cur_task || xSemaphoreTakeRecursive(s_once_mux, portMAX_DELAY) == pdTRUE)
{
if (!once_control->init_executed) {
do_execute = 1;
once_control->init_executed = 1;
}
if (cur_task) {
xSemaphoreGiveRecursive(s_once_mux);
}
if (do_execute) {
ESP_LOGV(TAG, "%s: call init_routine %p", __FUNCTION__, once_control);
init_routine();
}
}
else
{
ESP_LOGE(TAG, "%s: Failed to lock!", __FUNCTION__);
return EBUSY;
}
return 0;
}
/***************** MUTEX ******************/
static int mutexattr_check(const pthread_mutexattr_t *attr)
{
if (attr->type < PTHREAD_MUTEX_NORMAL || attr->type > PTHREAD_MUTEX_RECURSIVE) {
return EINVAL;
}
return 0;
}
int pthread_mutex_init(pthread_mutex_t *mutex, const pthread_mutexattr_t *attr)
{
int type = PTHREAD_MUTEX_NORMAL;
if (!mutex) {
return EINVAL;
}
if (attr) {
if (!attr->is_initialized) {
return EINVAL;
}
int res = mutexattr_check(attr);
if (res) {
return res;
}
type = attr->type;
}
esp_pthread_mutex_t *mux = (esp_pthread_mutex_t *)malloc(sizeof(esp_pthread_mutex_t));
if (!mux) {
return ENOMEM;
}
mux->type = type;
if (mux->type == PTHREAD_MUTEX_RECURSIVE) {
mux->sem = xSemaphoreCreateRecursiveMutex();
} else {
mux->sem = xSemaphoreCreateMutex();
}
if (!mux->sem) {
free(mux);
return EAGAIN;
}
*mutex = (pthread_mutex_t)mux; // pointer value fit into pthread_mutex_t (uint32_t)
return 0;
}
int pthread_mutex_destroy(pthread_mutex_t *mutex)
{
esp_pthread_mutex_t *mux;
ESP_LOGV(TAG, "%s %p", __FUNCTION__, mutex);
if (!mutex) {
return EINVAL;
}
mux = (esp_pthread_mutex_t *)*mutex;
// check if mux is busy
int res = pthread_mutex_lock_internal(mux, 0);
if (res == EBUSY) {
return EBUSY;
}
vSemaphoreDelete(mux->sem);
free(mux);
return 0;
}
static int IRAM_ATTR pthread_mutex_lock_internal(esp_pthread_mutex_t *mux, TickType_t tmo)
{
if (mux->type == PTHREAD_MUTEX_RECURSIVE) {
if (xSemaphoreTakeRecursive(mux->sem, tmo) != pdTRUE) {
return EBUSY;
}
} else {
if (xSemaphoreTake(mux->sem, tmo) != pdTRUE) {
return EBUSY;
}
}
return 0;
}
static int pthread_mutex_init_if_static(pthread_mutex_t *mutex) {
int res = 0;
if ((intptr_t) *mutex == PTHREAD_MUTEX_INITIALIZER) {
portENTER_CRITICAL(&s_mutex_init_lock);
if ((intptr_t) *mutex == PTHREAD_MUTEX_INITIALIZER) {
res = pthread_mutex_init(mutex, NULL);
}
portEXIT_CRITICAL(&s_mutex_init_lock);
}
return res;
}
int IRAM_ATTR pthread_mutex_lock(pthread_mutex_t *mutex)
{
if (!mutex) {
return EINVAL;
}
int res = pthread_mutex_init_if_static(mutex);
if (res != 0) {
return res;
}
return pthread_mutex_lock_internal((esp_pthread_mutex_t *)*mutex, portMAX_DELAY);
}
int IRAM_ATTR pthread_mutex_trylock(pthread_mutex_t *mutex)
{
if (!mutex) {
return EINVAL;
}
int res = pthread_mutex_init_if_static(mutex);
if (res != 0) {
return res;
}
return pthread_mutex_lock_internal((esp_pthread_mutex_t *)*mutex, 0);
}
int IRAM_ATTR pthread_mutex_unlock(pthread_mutex_t *mutex)
{
esp_pthread_mutex_t *mux;
if (!mutex) {
return EINVAL;
}
mux = (esp_pthread_mutex_t *)*mutex;
if (mux->type == PTHREAD_MUTEX_RECURSIVE) {
xSemaphoreGiveRecursive(mux->sem);
} else {
xSemaphoreGive(mux->sem);
}
return 0;
}
int pthread_mutexattr_init(pthread_mutexattr_t *attr)
{
if (!attr) {
return EINVAL;
}
attr->type = PTHREAD_MUTEX_NORMAL;
attr->is_initialized = 1;
return 0;
}
int pthread_mutexattr_destroy(pthread_mutexattr_t *attr)
{
if (!attr) {
return EINVAL;
}
attr->is_initialized = 0;
return 0;
}
int pthread_mutexattr_gettype(const pthread_mutexattr_t *attr, int *type)
{
ESP_LOGE(TAG, "%s: not supported!", __FUNCTION__);
return ENOSYS;
}
int pthread_mutexattr_settype(pthread_mutexattr_t *attr, int type)
{
if (!attr) {
return EINVAL;
}
pthread_mutexattr_t tmp_attr = {.type = type};
int res = mutexattr_check(&tmp_attr);
if (!res) {
attr->type = type;
}
return res;
}
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