devfs_lookupname
if (devfs_lookupname(curr, NULL, &vp) == 0 && vp) {
if (devfs_lookupname(dirpath, NULLVPP, &dirvp)) {
error = devfs_lookupname(pathname, NULLVPP, &dvp);
extern int devfs_lookupname(char *, vnode_t **, vnode_t **);