/*
 * FreeRTOS V202112.00
 * 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.
 *
 * https://www.FreeRTOS.org
 * https://aws.amazon.com/freertos
 *
 */

/**
 * Create a single persistent task which periodically dynamically creates another
 * two tasks.  The original task is called the creator task, the two tasks it
 * creates are called suicidal tasks.
 *
 * One of the created suicidal tasks kill one other suicidal task before killing
 * itself - 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>
 */


#include <stdlib.h>

/* Scheduler include files. */
#include "FreeRTOS.h"
#include "task.h"

/* Demo program include files. */
#include "death.h"

#define deathSTACK_SIZE    ( configMINIMAL_STACK_SIZE + 60 )

/* The task originally created which is responsible for periodically dynamically
 * creating another four tasks. */
static portTASK_FUNCTION_PROTO( vCreateTasks, pvParameters );

/* The task function of the dynamically created tasks. */
static portTASK_FUNCTION_PROTO( vSuicidalTask, 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 uint16_t usCreationCount = 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 UBaseType_t uxTasksRunningAtStart = 0;

/* When a task deletes itself, it stack and TCB are cleaned up by the Idle task.
 * Under heavy load the idle task might not get much processing time, so it would
 * be legitimate for several tasks to remain undeleted for a short period.  There
 * may also be a few other unexpected tasks if, for example, the tasks that test
 * static allocation are also being used. */
static const UBaseType_t uxMaxNumberOfExtraTasksRunning = 3;

/* Used to store a handle to the task that should be killed by a suicidal task,
 * before it kills itself. */
TaskHandle_t xCreatedTask;

/*-----------------------------------------------------------*/

void vCreateSuicidalTasks( UBaseType_t uxPriority )
{
    xTaskCreate( vCreateTasks, "CREATOR", deathSTACK_SIZE, ( void * ) NULL, uxPriority, NULL );
}
/*-----------------------------------------------------------*/

static portTASK_FUNCTION( vSuicidalTask, pvParameters )
{
    volatile long l1, l2;
    TaskHandle_t xTaskToKill;
    const TickType_t xDelay = pdMS_TO_TICKS( ( TickType_t ) 200 );

    /* Test deletion of a task's secure context, if any. */
    portALLOCATE_SECURE_CONTEXT( configMINIMAL_SECURE_STACK_SIZE );

    if( pvParameters != NULL )
    {
        /* This task is periodically created four times.  Two 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. */
        l1 = 2;
        l2 = 89;
        l2 *= l1;
        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 portTASK_FUNCTION( vCreateTasks, pvParameters )
{
    const TickType_t xDelay = pdMS_TO_TICKS( ( TickType_t ) 1000 );
    UBaseType_t uxPriority;

    /* Remove compiler warning about unused parameter. */
    ( void ) pvParameters;

    /* Delay at the start to ensure tasks created by other demos have been
     * created before storing the current number of tasks. */
    vTaskDelay( xDelay );
    uxTasksRunningAtStart = ( UBaseType_t ) uxTaskGetNumberOfTasks();

    uxPriority = uxTaskPriorityGet( NULL );

    for( ; ; )
    {
        /* Just loop round, delaying then creating the four suicidal tasks. */
        vTaskDelay( xDelay );

        xCreatedTask = NULL;

        xTaskCreate( vSuicidalTask, "SUICID1", configMINIMAL_STACK_SIZE, NULL, uxPriority, &xCreatedTask );
        xTaskCreate( vSuicidalTask, "SUICID2", configMINIMAL_STACK_SIZE, &xCreatedTask, uxPriority, NULL );

        ++usCreationCount;
    }
}
/*-----------------------------------------------------------*/

/* This is called to check that the creator task is still running and that there
 * are not any more than four extra tasks. */
BaseType_t xIsCreateTaskStillRunning( void )
{
    static uint16_t usLastCreationCount = 0xfff;
    BaseType_t xReturn = pdTRUE;
    static UBaseType_t uxTasksRunningNow;

    if( usLastCreationCount == usCreationCount )
    {
        xReturn = pdFALSE;
    }
    else
    {
        usLastCreationCount = usCreationCount;
    }

    uxTasksRunningNow = ( UBaseType_t ) uxTaskGetNumberOfTasks();

    if( uxTasksRunningNow < uxTasksRunningAtStart )
    {
        xReturn = pdFALSE;
    }
    else if( ( uxTasksRunningNow - uxTasksRunningAtStart ) > uxMaxNumberOfExtraTasksRunning )
    {
        xReturn = pdFALSE;
    }
    else
    {
        /* Everything is okay. */
    }

    return xReturn;
}
