/* ------------------------ main.c ------------------------ */
# include <stdio.h>
# include <stdlib.h>
# include <unistd.h>
# include <sys/wait.h>
# include <signal.h>
# include "sign.h"
# include "count.h"

int main() {
   int pid, ppid, status, child_nr; 
   if ((install_lm_sig(SIGUSR1) == SIG_ERR) ||
       (install_lm_sig(SIGUSR2) == SIG_ERR)) perror("install_sig"), exit(1);
   for(child_nr = 1; child_nr <= 2; child_nr++) {
      switch(pid = fork()) {
	 case -1: perror("fork"); exit(1);
 	 case 0 : {
	    long mypid; 
	    int i, sleeptime = 1; 
	    if (install_ct_sig(SIGUSR2) == SIG_ERR) {
	       perror("install_ct_sig"); exit(1);
	    }
	    ppid = getppid(); mypid = getpid();
	    for(i = 1; i <= 5; i++) {
	       int tries = 10;
	       while((sleep(sleeptime) <= 0 ) && (tries > 0)) {
		  fprintf(stderr, "P() : %ld\n", mypid);
		  if (kill(ppid,SIGUSR1) < 0) {
		     perror("kill");
		     exit(1);
		  } 
		  tries--;
	       }
	       if (tries <= 0) {
		  fprintf(stderr, "%ld: couldn't get the lock!\n", mypid);
		  exit(2);
	       }
		     /* have the lock: */
	       count(mypid, 1);
	       fprintf(stderr, "V() : %ld\n", mypid);
	       if (kill(ppid,SIGUSR2) < 0 ) {
		  perror("kill"); exit(1);
	       } 
	    } /*for*/
	    exit(0);
	 }
	 default:;
      }
   }
   wait(&status); 
   wait(&status); 
   sleep(1);
   printf("Parent: going to exit!\n");
   exit(0);
}