Enchant permanent
(Target a(n) permanent as you cast this. This card enters the battlefield attached to that permanent.)
When Rune of Sustenance enters the battlefield, draw a card.
As long as enchanted permanent is a creature, it has
lifelink (Damage dealt by the creature also causes its controller to gain that much life.).
As long as enchanted permanent is an Equipment, it has "Equipped creature has
lifelink (Damage dealt by the creature also causes its controller to gain that much life.)."