pppopen            67 kern/tty_conf.c int	pppopen(dev_t dev, struct tty *tp);
pppopen           123 kern/tty_conf.c 	{ pppopen, pppclose, pppread, pppwrite, ppptioctl,
pppopen           129 net/ppp_tty.c  int	pppopen(dev_t dev, struct tty *tp);