#include <stdlib.h>
#include <pvm3.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <signal.h>

#define EXE "pvm_signal"

void signal_h(int);

int signal_recv = 0;
sigset_t sigset;

int main(){
  int mytid, mygid;
  int child;

  mytid = pvm_mytid();

  if(pvm_parent() == PvmNoParent){
    struct sigaction newact;
    sigset_t blockset;
    sigset_t emptyset;

    mygid = pvm_joingroup("master");
    newact.sa_handler = signal_h;
    newact.sa_flags = 0;
    sigemptyset(&newact.sa_mask);
    sigemptyset(&emptyset);
    sigemptyset(&blockset);
    sigaddset(&blockset, SIGUSR1);
    sigaddset(&newact.sa_mask, SIGUSR1);
    if(sigaction(SIGUSR1, &newact, NULL) < 0)
      fprintf(stderr, "Failed to install handler!\n");
    pvm_spawn(EXE,NULL,PvmTaskDefault,NULL,1,&child);
    sigprocmask(SIG_BLOCK, &blockset, NULL);
    while(!signal_recv)
      sigsuspend(&emptyset);
    sigprocmask(SIG_SETMASK, &emptyset, NULL);
  }
  else{
    //Do nothing for a while, then signal the master
    mygid = pvm_joingroup("slave");
    sleep(5);
    pvm_sendsig(pvm_parent(),SIGUSR1);
  }
  pvm_exit();
  return 1;
}

void signal_h(int signo){
  if(signo == SIGUSR1){
    fprintf(stderr, "Got a SIGUSR1\n");
    signal_recv = 1;
  } 
}