/* Demonstrate what happens when the Child gets killed if we have    */
/* a parent piping to a Child who in turn pipes to a grandchild.     */
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

main(argc,argv)
int argc;
char *argv[];
{pid_t IsParent,IsChild;
 int WriteError=1,ReadError=1,Pipefd[2],Pipefd2[2],N;
 div_t Result;
 printf("!\n"); 
 pipe(Pipefd);
 IsParent=fork();
 if (IsParent) {
  dup2(Pipefd[1],1);
  close(Pipefd[1]);
  close(Pipefd[0]);
  N=0;
  while (1) {
		 /* Continually write Numbers to the Pipe */
   if ((WriteError=write(1,&N,sizeof(int)))<0) {  
    perror("Parent Failed due to");
    exit(1);
   } 
   Result=div(N++,10);
   fprintf(stderr,"Parent Sends %d\n",N);
   sleep(1);
  }
 }
 else { /* Child receives thru the pipe */
  pipe(Pipefd2);
  IsChild=fork();
  if (IsChild>0) {
   dup2(Pipefd[0],0);
   close(Pipefd[1]);
   close(Pipefd[0]);
   dup2(Pipefd2[1],1);
   close(Pipefd2[1]);
   close(Pipefd2[0]);
   while (ReadError) {
    if ((ReadError=read(0,&N,sizeof(int)))<0){   
			/* Continually read Numbers from the Pipe */
     perror("Got a -1");
     exit(1);
    }
    write(1,&N,sizeof(int));
    fprintf(stderr," Child processes %d - Read Result: %d\n",N,ReadError);
    sleep(2);	/* Slow Things Down */
   }
  }
  else {  /* GrandChild */
   dup2(Pipefd2[0],0);
   close(Pipefd2[1]);
   close(Pipefd2[0]);
   while (ReadError) {
    if ((ReadError=read(0,&N,sizeof(int)))<0){   
			/* Continually read Numbers from the Pipe */
     perror("Got a -1");
     exit(1);
    }
    fprintf(stderr," GrandChild Received %d - Read Result: %d\n",N,ReadError);
    if (N==5) 
     kill(getppid(),9);
   }
  }
 }
}