routine fsys_getroot(
    fsys: fsys_t;
    ureplyport ureply: mig_reply_port_t;
    dotdot_node: mach_port_send_t;
    gen_uids: idarray_t;
    gen_gids: idarray_t;
    flags: int;
    out do_retry: retry_type;
    out retry_name: string_t;
    out file: mach_port_send_t);

Return a file to the root of the filesystem. flags are as for dir lookup (but O_CREAT and O_EXCL are not meaningful). do_retry, retry_name, and result are as for dir lookup. The port should be authenticated with gen_uids and gen_gids (except, of course, for FS_RETRY_REAUTH and FS_RETRY_MAGICAL). dotdot_node is an unauthenticated port for the directory in which this root is located.