#include "main.h"
//======================================================================
/*
$ ps aux # a:all users, u:detailled, x:daemons // look at bash  PID

Unidirectional pipe : you have to choose the direction
PARENT					   CHILD
		  1 >> pipe >> 0 X						
printf	  0 << pipe << 1 <----- stdout <<  gunzip << stdin <-- inputFd

*/
//======================================================================
int main(int argc, char **argv)
{
	int ok;
	int value=100;
	char *msg;
	char buffer[0x100];
	
	int inputFd;
	
	bool usePause=false;

	if ( argc != 2 ) { printf("usage : ./prog11_proc_redir file_to_unzip \n"); return 0; }
	
	int pipeFd[2]; // Declare pipe, then create
	ok = pipe(pipeFd);
						if( ok == -1 ) { perror("pipe"); exit(1); }
	
	pid_t child=fork(); //>>>>>>>> CREATE CHILD >>>>>>>>>>>>>>>>>>>>>>>>
  
	switch(child)
	{
		case -1: perror("fork"); return EXIT_FAILURE; break;
		
		//############ CHILD CODE ######################################
		case 0 : 

				inputFd=open(argv[1],O_RDONLY);
							if(inputFd==-1) { perror("open"); exit(1); }
				ok = dup2(inputFd,0); 
							if (ok==-1) { perror("dup2"); exit(1); }
				close(inputFd); 		// redirected so useless now
				close(pipeFd[0]);		 // child1 will not read from this pipe
				ok = dup2(pipeFd[1],1);
							if (ok==-1) { perror("dup2"); exit(1); }
				close(pipeFd[1]); // redirected so useless now
				
				char *args[]={ "sort", (char *)0 };
				ok = execvp("sort",args);
							if (ok==-1) { perror("execvp"); exit(1); }							
				
				break;		
		
		//############ PARENT CODE #####################################
		default : 
				 for(;;)
				 {
					int r=read(pipeFd[0],buffer,0xFF);
							if(r==0) break; // end of file
							if(r==-1) { perror("read"); exit(1); }
					buffer[r]='\0';
					printf("parent received [%s]\n",buffer);
				}
				
			close(pipeFd[0]); // done with reading		

			int status;
		    pid_t p=waitpid(child,&status,0);	// PARENT MUST WAIT FOR HIS CHILD
								if(p==-1) { perror("waitpid");  return EXIT_FAILURE; }
			break;
	}	
			
return EXIT_SUCCESS;
}
//^^^^^^^^^^^^^^^^^^^^^^^^^^ EOF ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^