1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
|
/*
* FreeRTOS Kernel V10.3.0
* 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;
}
|
