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/*
* FreeRTOS Kernel V10.4.1
* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* http://www.FreeRTOS.org
* http://aws.amazon.com/freertos
*
* 1 tab == 4 spaces!
*/
/**
* Create a single persistent task which periodically dynamically creates another
* four tasks. The original task is called the creator task, the four tasks it
* creates are called suicidal tasks.
*
* Two of the created suicidal tasks kill one other suicidal task before killing
* themselves - leaving just the original task remaining.
*
* The creator task must be spawned after all of the other demo application tasks
* as it keeps a check on the number of tasks under the scheduler control. The
* number of tasks it expects to see running should never be greater than the
* number of tasks that were in existence when the creator task was spawned, plus
* one set of four suicidal tasks. If this number is exceeded an error is flagged.
*
* \page DeathC death.c
* \ingroup DemoFiles
* <HR>
*/
/*
Changes from V2.0.0
+ Delay periods are now specified using variables and constants of
TickType_t rather than unsigned long.
*/
#include <stdlib.h>
/* Scheduler include files. */
#include "FreeRTOS.h"
#include "task.h"
/* Demo program include files. */
#include "death.h"
#include "print.h"
#define deathSTACK_SIZE ( ( unsigned short ) 512 )
/* The task originally created which is responsible for periodically dynamically
creating another four tasks. */
static void vCreateTasks( void *pvParameters );
/* The task function of the dynamically created tasks. */
static void vSuicidalTask( void *pvParameters );
/* A variable which is incremented every time the dynamic tasks are created. This
is used to check that the task is still running. */
static volatile short sCreationCount = 0;
/* Used to store the number of tasks that were originally running so the creator
task can tell if any of the suicidal tasks have failed to die. */
static volatile unsigned portBASE_TYPE uxTasksRunningAtStart = 0;
static const unsigned portBASE_TYPE uxMaxNumberOfExtraTasksRunning = 5;
/* Used to store a handle to the tasks that should be killed by a suicidal task,
before it kills itself. */
TaskHandle_t xCreatedTask1, xCreatedTask2;
/*-----------------------------------------------------------*/
void vCreateSuicidalTasks( unsigned portBASE_TYPE uxPriority )
{
unsigned portBASE_TYPE *puxPriority;
/* Create the Creator tasks - passing in as a parameter the priority at which
the suicidal tasks should be created. */
puxPriority = ( unsigned portBASE_TYPE * ) pvPortMalloc( sizeof( unsigned portBASE_TYPE ) );
*puxPriority = uxPriority;
xTaskCreate( vCreateTasks, "CREATOR", deathSTACK_SIZE, ( void * ) puxPriority, uxPriority, NULL );
/* Record the number of tasks that are running now so we know if any of the
suicidal tasks have failed to be killed. */
uxTasksRunningAtStart = uxTaskGetNumberOfTasks();
}
/*-----------------------------------------------------------*/
static void vSuicidalTask( void *pvParameters )
{
portDOUBLE d1, d2;
TaskHandle_t xTaskToKill;
const TickType_t xDelay = ( TickType_t ) 500 / portTICK_PERIOD_MS;
if( pvParameters != NULL )
{
/* This task is periodically created four times. Tow created tasks are
passed a handle to the other task so it can kill it before killing itself.
The other task is passed in null. */
xTaskToKill = *( TaskHandle_t* )pvParameters;
}
else
{
xTaskToKill = NULL;
}
for( ;; )
{
/* Do something random just to use some stack and registers. */
d1 = 2.4;
d2 = 89.2;
d2 *= d1;
vTaskDelay( xDelay );
if( xTaskToKill != NULL )
{
/* Make sure the other task has a go before we delete it. */
vTaskDelay( ( TickType_t ) 0 );
/* Kill the other task that was created by vCreateTasks(). */
vTaskDelete( xTaskToKill );
/* Kill ourselves. */
vTaskDelete( NULL );
}
}
}/*lint !e818 !e550 Function prototype must be as per standard for task functions. */
/*-----------------------------------------------------------*/
static void vCreateTasks( void *pvParameters )
{
const TickType_t xDelay = ( TickType_t ) 1000 / portTICK_PERIOD_MS;
unsigned portBASE_TYPE uxPriority;
const char * const pcTaskStartMsg = "Create task started.\r\n";
/* Queue a message for printing to say the task has started. */
vPrintDisplayMessage( &pcTaskStartMsg );
uxPriority = *( unsigned portBASE_TYPE * ) pvParameters;
vPortFree( pvParameters );
for( ;; )
{
/* Just loop round, delaying then creating the four suicidal tasks. */
vTaskDelay( xDelay );
xTaskCreate( vSuicidalTask, "SUICIDE1", deathSTACK_SIZE, NULL, uxPriority, &xCreatedTask1 );
xTaskCreate( vSuicidalTask, "SUICIDE2", deathSTACK_SIZE, &xCreatedTask1, uxPriority, NULL );
xTaskCreate( vSuicidalTask, "SUICIDE1", deathSTACK_SIZE, NULL, uxPriority, &xCreatedTask2 );
xTaskCreate( vSuicidalTask, "SUICIDE2", deathSTACK_SIZE, &xCreatedTask2, uxPriority, NULL );
++sCreationCount;
}
}
/*-----------------------------------------------------------*/
/* This is called to check that the creator task is still running and that there
are not any more than four extra tasks. */
portBASE_TYPE xIsCreateTaskStillRunning( void )
{
static short sLastCreationCount = 0;
short sReturn = pdTRUE;
unsigned portBASE_TYPE uxTasksRunningNow;
if( sLastCreationCount == sCreationCount )
{
sReturn = pdFALSE;
}
uxTasksRunningNow = uxTaskGetNumberOfTasks();
if( uxTasksRunningNow < uxTasksRunningAtStart )
{
sReturn = pdFALSE;
}
else if( ( uxTasksRunningNow - uxTasksRunningAtStart ) > uxMaxNumberOfExtraTasksRunning )
{
sReturn = pdFALSE;
}
else
{
/* Everything is okay. */
}
return sReturn;
}
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