n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
{
	struct n_tty_data *ldata = tty->disc_data;

	if (I_IXON(tty)) {
		if (c == START_CHAR(tty)) {
			start_tty(tty);
			process_echoes(tty);
			return 0;
		}
		if (c == STOP_CHAR(tty)) {
			stop_tty(tty);
			return 0;
		}
	}

	if (L_ISIG(tty)) {
		if (c == INTR_CHAR(tty)) {
			n_tty_receive_signal_char(tty, SIGINT, c);
			return 0;
		} else if (c == QUIT_CHAR(tty)) {
			n_tty_receive_signal_char(tty, SIGQUIT, c);
			return 0;
		} else if (c == SUSP_CHAR(tty)) {
			n_tty_receive_signal_char(tty, SIGTSTP, c);
			return 0;
		}
	}

	if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) {
		start_tty(tty);
		process_echoes(tty);
	}

	if (c == '\r') {
		if (I_IGNCR(tty))
			return 0;
		if (I_ICRNL(tty))
			c = '\n';
	} else if (c == '\n' && I_INLCR(tty))
		c = '\r';

	if (ldata->icanon) {
		if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
		    (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
			eraser(c, tty);
			commit_echoes(tty);
			return 0;
		}
		if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
			ldata->lnext = 1;
			if (L_ECHO(tty)) {
				finish_erasing(ldata);
				if (L_ECHOCTL(tty)) {
					echo_char_raw('^', ldata);
					echo_char_raw('\b', ldata);
					commit_echoes(tty);
				}
			}
			return 1;
		}
		if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) {
			size_t tail = ldata->canon_head;

			finish_erasing(ldata);
			echo_char(c, tty);
			echo_char_raw('\n', ldata);
			while (tail != ldata->read_head) {
				echo_char(read_buf(ldata, tail), tty);
				tail++;
			}
			commit_echoes(tty);
			return 0;
		}
		if (c == '\n') {
			if (L_ECHO(tty) || L_ECHONL(tty)) {
				echo_char_raw('\n', ldata);
				commit_echoes(tty);
			}
			goto handle_newline;
		}
		if (c == EOF_CHAR(tty)) {
			c = __DISABLED_CHAR;
			goto handle_newline;
		}
		if ((c == EOL_CHAR(tty)) ||
		    (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
			/*
			 * XXX are EOL_CHAR and EOL2_CHAR echoed?!?
			 */
			if (L_ECHO(tty)) {
				/* Record the column of first canon char. */
				if (ldata->canon_head == ldata->read_head)
					echo_set_canon_col(ldata);
				echo_char(c, tty);
				commit_echoes(tty);
			}
			/*
			 * XXX does PARMRK doubling happen for
			 * EOL_CHAR and EOL2_CHAR?
			 */
			if (c == (unsigned char) '\377' && I_PARMRK(tty))
				put_tty_queue(c, ldata);

handle_newline:
			set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags);
			put_tty_queue(c, ldata);
			ldata->canon_head = ldata->read_head;
			kill_fasync(&tty->fasync, SIGIO, POLL_IN);
			if (waitqueue_active(&tty->read_wait))
				wake_up_interruptible(&tty->read_wait);
			return 0;
		}
	}

	if (L_ECHO(tty)) {
		finish_erasing(ldata);
		if (c == '\n')
			echo_char_raw('\n', ldata);
		else {
			/* Record the column of first canon char. */
			if (ldata->canon_head == ldata->read_head)
				echo_set_canon_col(ldata);
			echo_char(c, tty);
		}
		commit_echoes(tty);
	}

	/* PARMRK doubling check */
	if (c == (unsigned char) '\377' && I_PARMRK(tty))
		put_tty_queue(c, ldata);

	put_tty_queue(c, ldata);
	return 0;
}
Unknown