passdb_lookup()

CREATE FUNCTION passdb_lookup(TEXT)
RETURNS TABLE("user" TEXT, "password" TEXT)
LANGUAGE sql
AS $$
  SELECT
    name, password_digest
  FROM mailboxes
  WHERE (NOT is_alias) AND (active)
    AND ((lower($1) = name) OR (lower($1) = login))
  UNION
  SELECT
    lower($1), password_digest
  FROM mailboxes
  WHERE (active) AND id IN (
    SELECT
      parent_id
    FROM mailboxes
    WHERE (active) AND (is_login_alias)
      AND (lower($1) = name)
  )
$$;