Function ng_h4_open

freebsd/netgraph/bluetooth/drivers/h4/ng_h4.c:152–235

 */

static int
ng_h4_open(struct cdev *dev, struct tty *tp)
{
	struct thread	*td = curthread;
	char		 name[NG_NODESIZ];
	ng_h4_info_p	 sc = NULL;
	int		 error;

	/* Super-user only */
	error = priv_check(td, PRIV_NETGRAPH_TTY); /* XXX */
	if (error != 0)
		return (error);

	/* Initialize private struct */
	sc = malloc(sizeof(*sc), M_NETGRAPH_H4, M_NOWAIT|M_ZERO);
	if (sc == NULL)
		return (ENOMEM);

	sc->tp = tp;
	sc->debug = NG_H4_WARN_LEVEL;

	sc->state = NG_H4_W4_PKT_IND;
	sc->want = 1;
	sc->got = 0;

	mtx_init(&sc->outq.ifq_mtx, "ng_h4 node+queue", NULL, MTX_DEF);
	IFQ_SET_MAXLEN(&sc->outq, NG_H4_DEFAULTQLEN);
	ng_callout_init(&sc->timo);

	NG_H4_LOCK(sc);

	/* Setup netgraph node */
	error = ng_make_node_common(&typestruct, &sc->node);
	if (error != 0) {
		NG_H4_UNLOCK(sc);

		printf("%s: Unable to create new node!\n", __func__);

		mtx_destroy(&sc->outq.ifq_mtx);
		bzero(sc, sizeof(*sc));
		free(sc, M_NETGRAPH_H4);

		return (error);
	}

	/* Assign node its name */
	snprintf(name, sizeof(name), "%s%d", typestruct.name, ng_h4_node ++);

	error = ng_name_node(sc->node, name);
	if (error != 0) {
		NG_H4_UNLOCK(sc);

		printf("%s: %s - node name exists?\n", __func__, name);

		NG_NODE_UNREF(sc->node);
		mtx_destroy(&sc->outq.ifq_mtx);
		bzero(sc, sizeof(*sc));
		free(sc, M_NETGRAPH_H4);