#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

void executeredirect(char *s, int in, int out);
int makeargv(const char *s, const char *delimiters, char ***argvp);

static void perror_exit(char *s) {
   perror(s);
   exit(1);
}

void executecmd(char *cmds) {
   int child;
   int count;
   int fds[2];
   int i;
   char **pipelist;

   count = makeargv(cmds, "|", &pipelist);
   if (count <= 0) {
      fprintf(stderr, "Failed to find any commands\n");
      exit(1);
   }
   for (i = 0; i < count - 1; i++) {              /* handle all but last one */
      if (pipe(fds) == -1)
         perror_exit("Failed to create pipes");
      else if ((child = fork()) == -1) 
         perror_exit("Failed to create process to run command");
      else if (child) {                                       /* parent code */
         if (dup2(fds[1], STDOUT_FILENO) == -1)
            perror_exit("Failed to connect pipeline");
         if (close(fds[0]) || close(fds[1]))
            perror_exit("Failed to close needed files");
         executeredirect(pipelist[i], i==0, 0);
         exit(1);
      }
      if (dup2(fds[0], STDIN_FILENO) == -1)                    /* child code */
         perror_exit("Failed to connect last component");
      if (close(fds[0]) || close(fds[1]))
         perror_exit("Failed to do final close");
   }
   executeredirect(pipelist[i], i==0, 1);             /* handle the last one */
   exit(1);
}