Function ng_add_hook

lib/ff_ng_base.c:1069–1121

* Add an unconnected hook to a node. Only used internally. * Assumes node is locked. (XXX not yet true ) */

 * Assumes node is locked. (XXX not yet true )
 */
static int
ng_add_hook(node_p node, const char *name, hook_p *hookp)
{
    hook_p hook;
    int error = 0;

    /* Check that the given name is good */
    if (name == NULL) {
        TRAP_ERROR();
        return (EINVAL);
    }
    if (ng_findhook(node, name) != NULL) {
        TRAP_ERROR();
        return (EEXIST);
    }

    /* Allocate the hook and link it up */
    NG_ALLOC_HOOK(hook);
    if (hook == NULL) {
        TRAP_ERROR();
        return (ENOMEM);
    }
    hook->hk_refs = 1;        /* add a reference for us to return */
    hook->hk_flags = HK_INVALID;
    hook->hk_peer = &ng_deadhook;    /* start off this way */
    hook->hk_node = node;
    NG_NODE_REF(node);        /* each hook counts as a reference */

    /* Set hook name */
    strlcpy(NG_HOOK_NAME(hook), name, NG_HOOKSIZ);

    /*
     * Check if the node type code has something to say about it
     * If it fails, the unref of the hook will also unref the node.
     */
    if (node->nd_type->newhook != NULL) {
        if ((error = (*node->nd_type->newhook)(node, hook, name))) {
            NG_HOOK_UNREF(hook);    /* this frees the hook */
            return (error);
        }
    }
    /*
     * The 'type' agrees so far, so go ahead and link it in.
     * We'll ask again later when we actually connect the hooks.
     */
    LIST_INSERT_HEAD(&node->nd_hooks, hook, hk_hooks);
    node->nd_numhooks++;
    NG_HOOK_REF(hook);    /* one for the node */

    if (hookp)
        *hookp = hook;
    return (0);
}

/*
 * Find a hook