posix_sw_wd.c

basic feature example for vxWork, good example to start. include POSIX and vxwork library call.

/****************************************************************************/
/* Function: Interval timer software "watchdog" demonstration               */
/*                                                                          */
/* Sam Siewert - 7/22/97                                                    */
/*                                                                          */ 
/*                                                                          */
/****************************************************************************/

#include "stdio.h"
#include "stdlib.h"
#include "errnoLib.h"
#include "timers.h"
#include "signal.h"

static int monitored_tid;
static int monitor_interval_expcount = 0;
static timer_t wd_timer_1;
static struct itimerspec itime = {{2,500000000}, {2,500000000}};
static struct itimerspec last_itime;

#define TARDY_TERMINATOR 3

LOCAL void monitored (int arg1, int arg2, int arg3, int arg4, int arg5, int arg6, int arg7, int arg8, int arg9, int arg10);

void monitor_interval_expired(timer_t timerid, int mon_tid)
{
  monitor_interval_expcount++;

  printf("Monitor interval expired %d times for monitored task %d, timerid=%d\n",  monitor_interval_expcount, mon_tid, (int)timerid);

  if(monitor_interval_expcount <= TARDY_TERMINATOR) {
    printf("Respawning monitored task and resetting watchdog timer\n");
    taskDelete(mon_tid);
    /* Spawn a monitored task to watch and respawn/terminate */
    if ((monitored_tid = taskSpawn ("monitored", 75, 0, (1024*8),
       (FUNCPTR) monitored, 0,0,0,0,0,0,0,0,0,0)) == ERROR) {
      printf ("Error creating monitored task to signal\n");
      return;
    }
    printf ("Task to monitor has been spawned, id=%x ... resetting monitor for new taskid\n", monitored_tid);
    fflush(stdout);

    timer_connect(wd_timer_1, (void(*)()) monitor_interval_expired, monitored_tid);
  }
  else {
    printf("Task was late more than 3 times -- you will be terminated!\n"); 
    taskDelete(monitored_tid);
  }

}


LOCAL void monitored (int arg1, int arg2, int arg3, int arg4, int arg5,
                 int arg6, int arg7, int arg8, int arg9, int arg10) {
  int flags = 0;
  int delay;


  while(1) {

    delay = rand() % 180;
   
    /* delay between 0 and 3 seconds; given tick=1/60 sec */ 
    printf("Tasking being delayed for %d ticks\n", delay);
    taskDelay(delay);
   
    /* arm the timer again -- "hit the snooze button before alarm" */
    timer_settime(wd_timer_1, flags, &itime, &last_itime);

  }

}


void soft_wd_test(void) {

  int i;
  int flags = 0;
  uint_t seed = 554317400;

  srand(seed);

  monitor_interval_expcount = 0;

  /* set up to signal SIGALRM if timer expires */
  timer_create(CLOCK_REALTIME, NULL, &wd_timer_1);

  /* Spawn a monitored task to watch and respawn/terminate */
  if ((monitored_tid = taskSpawn ("monitored", 75, 0, (1024*8),
     (FUNCPTR) monitored, 0,0,0,0,0,0,0,0,0,0)) == ERROR) {
    printf ("Error creating monitored task to signal\n");
    return;
  }
  printf ("Task to monitor has been spawned, id=%d\n", monitored_tid);
  fflush(stdout);

  timer_connect(wd_timer_1, (void(*)()) monitor_interval_expired, monitored_tid);

  /* arm the wd timer for 2 second interval */
  itime.it_interval.tv_sec = 2;
  itime.it_interval.tv_nsec = 500000000;
  itime.it_value.tv_sec = 2;
  itime.it_value.tv_nsec = 500000000;

  timer_settime(wd_timer_1, flags, &itime, &last_itime);

  while(1) {
    if(monitor_interval_expcount > TARDY_TERMINATOR) {
      timer_delete(wd_timer_1);
      printf ("\nAll done\n");
      exit(0);
    }
    else
      pause();
  }

}