POLL_IN
case POLL_IN:
pipeselwakeup(wpipe, wpipe, POLL_IN);
pipeselwakeup(wpipe, wpipe, POLL_IN);
case POLL_IN:
a = POLL_IN;
fownsignal(tp->tun_pgid, SIGIO, POLL_IN, POLLIN|POLLRDNORM,
sowakeup(so, &so->so_rcv, POLL_IN);