code: func reOpenDevNull(rootfs string) error {
  	var stat, devNullStat syscall.Stat_t
  	file, err := os.Open("/dev/null")
  	if err != nil {
  		return fmt.Errorf("Failed to open /dev/null - %s", err)
  	}
  	defer file.Close()
  	if err := syscall.Fstat(int(file.Fd()), &devNullStat); err != nil {
  		return err
  	}
  	for fd := 0; fd < 3; fd++ {
  		if err := syscall.Fstat(fd, &stat); err != nil {
  			return err
  		}
  		if stat.Rdev == devNullStat.Rdev {
  			// Close and re-open the fd.
  			if err := syscall.Dup3(int(file.Fd()), fd, 0); err != nil {
  				return err
  			}
  		}
  	}
  	return nil
  }
docs: // If stdin, stdout, and/or stderr are pointing to `/dev/null` in the parent's rootfs
  // this method will make them point to `/dev/null` in this container's rootfs.  This
  // needs to be called after we chroot/pivot into the container's rootfs so that any
  // symlinks are resolved locally.