/*
*
* This is a simple real-time applications which contains 3 periodic tasks.
*
* Task A is an independent task.
*
* Task B and C share a data.
*
* Tasks are implemented as POSIX threads.
*
* The share data is protected with a POSIX mutex.
*
* Other POSIX facilities such as timers, condition, .. is also used
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.OARcorp.com/rtems/license.html.
*
* $Id$
*/
#define CONFIGURE_INIT
#include "system.h"
#include <pthread.h> /* thread facilities */
#include <signal.h> /* signal facilities */
#include <unistd.h> /* sleep facilities */
#include <sched.h> /* schedule facilities */
#include <time.h> /* time facilities */
#include <stdio.h> /* console facilities */
/* temporal parameters of a task */
struct periodic_params {
struct timespec period;
int signo; /* signal number */
int id; /* task identification */
};
pthread_attr_t attr;
/* shared datum */
struct shared_data {
pthread_mutex_t mutex;
pthread_cond_t sync;
int updated;
int x;
};
struct shared_data data;
/* task A */
void * task_a (void *arg)
{
struct timespec my_period;
int my_sig, received_sig;
struct itimerspec timerdata;
timer_t timer_id;
time_t clock;
struct sigevent event;
sigset_t set;
my_period = ((struct periodic_params*) arg)->period;
my_sig = ((struct periodic_params*) arg)->signo;
/* timer create */
event.sigev_notify = SIGEV_SIGNAL;
event.sigev_signo = my_sig;
if (timer_create (CLOCK_REALTIME, &event, &timer_id) == -1) {
perror ("Error in timer creation\n");
pthread_exit ((void *) -1);
}
/* block the timer signal */
sigemptyset (&set);
sigaddset (&set,my_sig);
pthread_sigmask(SIG_BLOCK,&set,NULL);
/* set the timer in periodic mode */
timerdata.it_interval = my_period;
timerdata.it_value = my_period;
if (timer_settime(timer_id, 0, &timerdata, NULL) == -1) {
perror ("Error in timer setting\n");
pthread_exit ((void *) -1);
}
/* periodic activity */
while(1) {
if (sigwait(&set,&received_sig) == -1) {
perror ("Error in sigwait\n");
}
clock = time(NULL);
printf("Executing task A %s", ctime(&clock));
}
}
/* task B */
void * task_b (void *arg)
{
struct timespec my_period;
int my_sig, received_sig;
struct itimerspec timerdata;
timer_t timer_id;
time_t clock;
struct sigevent event;
sigset_t set;
int x; /* value to be copied to the shared datum */
my_period = ((struct periodic_params*) arg)->period;
my_sig = ((struct periodic_params*) arg)->signo;
x = 1;
/* timer create */
event.sigev_notify = SIGEV_SIGNAL;
event.sigev_signo = my_sig;
if (timer_create (CLOCK_REALTIME, &event, &timer_id) == -1) {
perror ("Error in timer creation\n");
pthread_exit ((void *) -1);
}
/* block the timer signal */
sigemptyset (&set);
sigaddset (&set,my_sig);
pthread_sigmask(SIG_BLOCK,&set,NULL);
/* set the timer in periodic mode */
timerdata.it_interval = my_period;
timerdata.it_value = my_period;
if (timer_settime(timer_id, 0, &timerdata, NULL) == -1) {
perror ("Error in timer setting\n");
pthread_exit ((void *) -1);
}
/* periodic activity */
while(1) {
if (sigwait(&set,&received_sig) == -1) {
perror ("Error in sigwait\n");
pthread_exit ((void *) -1);
}
pthread_mutex_lock (&data.mutex);
clock = time(NULL);
printf("Executing task B with x = %i %s", x, ctime(&clock));
data.x = x;
data.updated = TRUE;
pthread_cond_signal (&data.sync);
pthread_mutex_unlock (&data.mutex);
x++;
}
}
/* task C */
void * task_c (void *arg)
{
struct timespec my_period;
int my_sig, received_sig;
struct itimerspec timerdata;
timer_t timer_id;
time_t clock;
struct sigevent event;
sigset_t set;
int x; /* value to be copied to the shared datum */
my_period = ((struct periodic_params*) arg)->period;
my_sig = ((struct periodic_params*) arg)->signo;
x = 0;
/* timer create */
event.sigev_notify = SIGEV_SIGNAL;
event.sigev_signo = my_sig;
if (timer_create (CLOCK_REALTIME, &event, &timer_id) == -1) {
perror ("Error in timer creation\n");
pthread_exit ((void *) -1);
}
/* block the timer signal */
sigemptyset (&set);
sigaddset (&set,my_sig);
pthread_sigmask(SIG_BLOCK,&set,NULL);
/* set the timer in periodic mode */
timerdata.it_interval = my_period;
timerdata.it_value = my_period;
if (timer_settime(timer_id, 0, &timerdata, NULL) == -1) {
perror ("Error in timer setting\n");
pthread_exit ((void *) -1);
}
/* periodic activity */
while(1) {
if (sigwait(&set,&received_sig) == -1) {
perror ("Error in sigwait\n");
pthread_exit ((void *) -1);
}
pthread_mutex_lock (&data.mutex);
while (data.updated == FALSE) {
pthread_cond_wait (&data.sync,&data.mutex);
}
x = data.x;
clock = time(NULL);
printf("Executing task C with x = %i %s", x, ctime(&clock));
pthread_mutex_unlock (&data.mutex);
}
}
/* main */
void *POSIX_Init (
void *argument
)
{
pthread_mutexattr_t mutexattr; /* mutex attributes */
pthread_condattr_t condattr; /* condition attributes */
pthread_attr_t attr; /* task attributes */
pthread_t ta,tb,tc; /* threads */
sigset_t set; /* signals */
struct sched_param sch_param; /* schedule parameters */
struct periodic_params params_a, params_b, params_c;
puts( "\n\n*** POSIX Timers Test ***" );
data.updated = FALSE;
data.x = 0;
/* mask signal */
sigemptyset (&set);
sigaddset (&set,SIGALRM);
pthread_sigmask (SIG_BLOCK,&set,NULL);
/* set mutex attributes */
if (pthread_mutexattr_init (&mutexattr) != 0) {
perror ("Error in mutex attribute init\n");
}
/* init mutex */
if (pthread_mutex_init (&data.mutex,&mutexattr) != 0) {
perror ("Error in mutex init");
}
/* init condition attributes */
if (pthread_condattr_init (&condattr) != 0) {
perror ("Error in condition attribute init\n");
}
/* init condition */
if (pthread_cond_init (&data.sync,&condattr) != 0) {
perror ("Error in condition init");
}
/* init task attributes */
if (pthread_attr_init(&attr) != 0) {
perror ("Error in attribute init\n");
}
/* set explicit schedule for every task */
if (pthread_attr_setinheritsched (&attr,
PTHREAD_EXPLICIT_SCHED) != 0) {
perror("Error in attribute inheritsched\n");
}
/* set task independent (join will not use) */
if (pthread_attr_setdetachstate (&attr,
PTHREAD_CREATE_DETACHED) != 0) {
perror ("Error in attribute detachstate\n");
}
/* schedule policy POSIX_FIFO (priority preemtive and FIFO within the same
priority) */
if (pthread_attr_setschedpolicy (&attr,
SCHED_FIFO) != 0) {
perror ("Error in attribute setschedpolicy\n");
}
/* set and create thread A with priority 1 */
sch_param.sched_priority = 1;
if (pthread_attr_setschedparam(&attr, &sch_param) != 0) {
perror ("Error in attribute schedparam\n");
}
/* Temporal parameters (1 sec. periodicity) */
params_a.period.tv_sec = 1; /* seconds */
params_a.period.tv_nsec = 000000000; /* nanoseconds */
params_a.signo = SIGALRM;
if (pthread_create (&ta, &attr, task_a, ¶ms_a) != 0 ) {
perror ("Error in thread create for task a\n");
}
/* set and create thread B with priority 15 */
sch_param.sched_priority = 15;
if (pthread_attr_setschedparam(&attr, &sch_param) != 0) {
perror ("Error in attribute schedparam");
}
/* Temporal parameters (2 sec. periodicity) */
params_b.period.tv_sec = 2; /* seconds */
params_b.period.tv_nsec = 000000000; /* nanoseconds */
params_b.signo = SIGALRM;
if (pthread_create (&tb, &attr, task_b, ¶ms_b) != 0) {
perror ("Error in thread create for task b\n");
}
/* set and create thread B with priority 14 */
sch_param.sched_priority = 14;
if (pthread_attr_setschedparam(&attr, &sch_param) != 0 ) {
perror ("Error in attribute schedparam\n");
}
/* Temporal parameters (3 sec. periodicity) */
params_c.period.tv_sec = 3; /* seconds */
params_c.period.tv_nsec = 000000000; /* nanoseconds */
params_c.signo = SIGALRM;
if (pthread_create (&tc, &attr, task_c, ¶ms_c) != 0) {
perror ("Error in trhead create for task c\n");
}
/* execute 20 seconds and finish */
sleep (20);
puts( "\n\n*** End of POSIX Timers Test ***" );
exit (0);
}
