/*
 * ISA 563, Spring 2011
 * Copyleft by Muhammad Abdulla
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <wait.h>
#include <sys/types.h>

/*
 * fork_exec.c -- demonstrate the fork system call, and command execution procedures.
 */

int main ( int argc, char *argv[] )
{
   int status;  // get child execution status

   const char *path = "/bin/ls";
   // prepare an array of arguments to be passed to execv system call (executed by child)
   char *args[] = { 
                    "ls",       // name of command to be executed
                    "/",        // ls target
                    "-l",       // arguments: -l for long options
                    "-a",       //            -a for all (list hidden files also)
                    "-S",       //            -S for sort
                    "--color",  //            make it colorful 
                    NULL        // end of  
                  };

   pid_t pid;

   pid = fork();

   if ( pid < 0 ) { // error condition
       fprintf(stderr, "Could not fork!\n");
       exit(-1);
   } else if ( pid == 0 ) {  // child process
       execv(path, args); 
   } else { // parent process
       waitpid(pid, &status, 0); 
       fprintf(stdout, "child exitted with code %d\n", status);
   }

   return 0;
}