tty: reading input from a tty is now handled by the line discipline

kernel/tty/tty.c

@@ -75,8 +75,14 @@ static void putchar(struct device *tty, int c)
 
 kern_status_t tty_read(struct device *tty, void *buf, size_t max, size_t *nr_read, socks_flags_t flags)
 {
-	printk("tty_read");
-	return KERN_OK;
+	kern_status_t status = KERN_UNSUPPORTED;
+	struct tty_device *ttydev = TTY_DEVICE(tty);
+
+	if (ttydev->tty_ldisc || ttydev->tty_ldisc->read) {
+		status = ttydev->tty_ldisc->read(tty, buf, max, nr_read, flags);
+	}
+
+	return status;
 }
 
 kern_status_t tty_write(struct device *tty, const void *buf, size_t len, size_t *nr_written, socks_flags_t flags)