I'm really lucky.

prepare_ctl_tty:
	e->fd           = get_service_fd(CTL_TTY_OFF); // -1 as fd is not set

send_fd_to_self:
if (dup2(fd, dfd) != dfd) { // tries to install sfd, but -1 == -1

tty_restore_ctl_terminal:
	if (!is_service_fd(fd, CTL_TTY_OFF))
		return fd == get_service_fd(type); // -1 = -1
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>