/* the waitpid(2) seems to indicate that only when the child is terminated will this wait return. */

	  waitpid(child, &childstatus, 0); 

	}

      (*rem)->pipe_write = pipe_write[1];

      (*rem)->pipe_read = pipe_read[0];

      (*rem)->state = 0;

      (*rem)->child = child;

      return 0;

    }

  /* child */

  else

    {

      /* close unused pipes */

      close(pipe_write[1]);

      close(pipe_read[0]);

      /*

	reset stdin, stdout, and stderr to the appropriate files. OK, not stderr :-) 

      */

      dup2(pipe_read[1], STDOUT_FILENO);

      dup2(pipe_write[0], STDIN_FILENO);

      /*

	close the fds that were dup'd

       */

      close(pipe_read[1]);

      close(pipe_write[0]);

      /* 

	 close all other file descriptors. We want to keep 0, 1, and 2 open. We don't know that the last open() or pipe() always gives the highest fd number. However, I will assume that it does. Maybe this is a bad idea:

       */

      counter = pipe_write[0];

      if(counter < pipe_write[1])

	counter = pipe_write[1];

      if(counter < pipe_read[0])

	counter = pipe_read[0];

      if(counter < pipe_read[1])

	counter = pipe_read[1];

      counter2 = 0;

      maxfds = counter;

      while(counter > 2)

	{

	  if(!close(counter))

	    counter2 ++; /* record how many descriptors we still had open :-) */

	  counter --;

	}

      /*

	now exec: execvp uses interpreter to find the file to exec

       */

      execvp(progname, argv);

      fprintf(stderr, "uh-oh, ``%s'' didn't start for execio\n", progname);

      exit(1);

    }

}

/*

  returns 1 if child has exited, 

  returns 0 if child is still alive

 */

int _execio_checkpid(struct execio *eio)

{

  int childstatus;

#ifdef _WIN32

  waitpid(eio->child, &childstatus, 0);

#else

  waitpid(eio->child, &childstatus, WNOHANG);

#endif

  /* perror()? */

  return WIFEXITED(childstatus);

}

int execio_read(struct execio *eio, const void *buf, size_t len, size_t *bytesread)

{

  ssize_t ret;

  /*

    TODO: detect NULL eio? 

    TODO: errno?

    update status of eio for execio_status/to be able to cleanup subproc??

    whenever read() returns 0, it means EOF

   */

  ret = read(eio->pipe_read, buf, len);

  if(ret == -1)

    {

      (*bytesread) = 0;

      perror("read");

      switch(errno)

	{

	case EAGAIN:

	case EINTR:

	  return 0;

	  break;

	default:

	  return 1;

	}

    }

  (*bytesread) = (size_t)ret;

  if(!ret)

    {

      /* should also be able to figure out if is bad fd and should set EXECIO_STATE_ERROR instead of _EOF */

      eio->state = EXECIO_STATE_EOF;

      return 1;

    }

  return 0;

}

int execio_write(struct execio *eio, const void *buf, size_t len, size_t *bytesread)

{

  errno = 0;

  (*bytesread) = write(eio->pipe_write, buf, len);

  if(!*bytesread)

    {

      switch(errno)

	{

	case EPIPE:

	  /* 

	     the program closed the pipe (died)

	  */

	default:

	  fprintf(stderr, "execio_write: unhandled error writing to an fd: \n");

	  perror("write");

	  eio->state = EXECIO_STATE_ERROR;

	  break;

	}

      return 1;

    }

  return 0;

}

enum execio_state execio_state(struct execio *eio)

{

  return eio->state;

}

int execio_close(struct execio *eio)

{

  int childstatus;

  close(eio->pipe_read);

  close(eio->pipe_write);

  /* maybe we should just kill rather than term the child */

  kill(eio->child, SIGTERM);

  /* 

     the waitpid(2) seems to indicate that only when the child is terminated will this wait return. 

     This are of code will probably need improving - the ability to seng SIGKILL after a timeout? So we'll output a debug line before running waitpid

  */

  waitpid(eio->child, &childstatus, 0);

  free(eio);

  return 0;

}