Function ngt_rcvmsg

freebsd/netgraph/ng_tty.c:247–304

* Receive control message */

 * Receive control message
 */
static int
ngt_rcvmsg(node_p node, item_p item, hook_p lasthook)
{
	struct proc *p;
	const sc_p sc = NG_NODE_PRIVATE(node);
	struct ng_mesg *msg, *resp = NULL;
	int error = 0;

	NGI_GET_MSG(item, msg);
	switch (msg->header.typecookie) {
	case NGM_TTY_COOKIE:
		switch (msg->header.cmd) {
		case NGM_TTY_SET_TTY:
			if (sc->tp != NULL)
				return (EBUSY);
			
			p = pfind(((int *)msg->data)[0]);
			if (p == NULL || (p->p_flag & P_WEXIT))
				return (ESRCH);
			_PHOLD(p);
			PROC_UNLOCK(p);
			error = ttyhook_register(&sc->tp, p, ((int *)msg->data)[1],
			    &ngt_hook, sc);
			PRELE(p);
			if (error != 0)
				return (error);
			break;
		case NGM_TTY_SET_HOTCHAR:
		    {
			int     hotchar;

			if (msg->header.arglen != sizeof(int))
				ERROUT(EINVAL);
			hotchar = *((int *) msg->data);
			if (hotchar != (u_char) hotchar && hotchar != -1)
				ERROUT(EINVAL);
			sc->hotchar = hotchar;	/* race condition is OK */
			break;
		    }
		case NGM_TTY_GET_HOTCHAR:
			NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT);
			if (!resp)
				ERROUT(ENOMEM);
			/* Race condition here is OK */
			*((int *) resp->data) = sc->hotchar;
			break;
		default:
			ERROUT(EINVAL);
		}
		break;
	default:
		ERROUT(EINVAL);
	}
done:
	NG_RESPOND_MSG(error, node, item, resp);
	NG_FREE_MSG(msg);
	return (error);
}