Function ttydisc_read_raw_interbyte_timer

freebsd/kern/tty_ttydisc.c:276–323

}

static int
ttydisc_read_raw_interbyte_timer(struct tty *tp, struct uio *uio, int ioflag)
{
	size_t vmin = tp->t_termios.c_cc[VMIN];
	ssize_t oresid = uio->uio_resid;
	int error;

	MPASS(tp->t_termios.c_cc[VMIN] != 0);
	MPASS(tp->t_termios.c_cc[VTIME] != 0);

	/*
	 * When using the interbyte timer, the timer should be started
	 * after the first byte has been received. We just call into the
	 * generic read timer code after we've received the first byte.
	 */

	for (;;) {
		error = tty_wait_background(tp, curthread, SIGTTIN);
		if (error)
			return (error);

		error = ttyinq_read_uio(&tp->t_inq, tp, uio,
		    uio->uio_resid, 0);
		if (error)
			return (error);
		if (uio->uio_resid == 0 || (oresid - uio->uio_resid) >= vmin)
			return (0);

		/*
		 * Not enough data, but we did receive some, which means
		 * we'll now start using the interbyte timer.
		 */
		if (oresid != uio->uio_resid)
			break;

		/* We have to wait for more. */
		if (tp->t_flags & TF_ZOMBIE)
			return (0);
		else if (ioflag & IO_NDELAY)
			return (EWOULDBLOCK);

		error = tty_wait(tp, &tp->t_inwait);
		if (error)
			return (error);
	}

	return ttydisc_read_raw_read_timer(tp, uio, ioflag, oresid);
}

int
ttydisc_read(struct tty *tp, struct uio *uio, int ioflag)