mac_vnode_check_open
if ((error = mac_vnode_check_open(cred, lvp, VEXEC | VREAD)) != 0)
error = mac_vnode_check_open(td->td_ucred, vp, VREAD);
error = mac_vnode_check_open(td->td_ucred, vp, VWRITE | VREAD);
error = mac_vnode_check_open(cred, vp, accmode);