PF_REMOTE
(pty->pt_flags & PF_REMOTE) ?
if (!(pty->pt_flags & PF_REMOTE)) {
if ((pty->pt_flags & PF_REMOTE) || uio->uio_resid > 0) {
pty->pt_flags |= PF_REMOTE;
pty->pt_flags &= ~PF_REMOTE;