+ struct file *file = vif;
+ return write(file->fd, buf, count);
+}
+
+static long file_seek(vi_file *vif, long offs, int whence)
+{
+ struct file *file = vif;
+ return lseek(file->fd, offs, whence);
+}
+
+/* tty operations */
+
+static void tty_clear(void *cls)
+{
+ term_clear();
+}
+
+static void tty_clear_line(void *cls)
+{
+ /* TODO */
+}
+
+static void tty_clear_line_at(int y, void *cls)
+{
+ term_setcursor(y, 0);
+ /* TODO */
+}
+
+static void tty_setcursor(int x, int y, void *cls)
+{
+ term_setcursor(y, x);
+}
+
+static void tty_putchar(char c, void *cls)
+{
+ term_putchar(c);
+}
+
+static void tty_putchar_at(int x, int y, char c, void *cls)
+{
+ term_setcursor(y, x);
+ term_putchar(c);
+}
+
+static void tty_scroll(int nlines, void *cls)
+{
+ /* TODO */