ligo/src/lib_signer_backends/ledger.ml

(*****************************************************************************)
(*                                                                           *)
(* Open Source License                                                       *)
(* Copyright (c) 2018 Dynamic Ledger Solutions, Inc. <contact@tezos.com>     *)
(*                                                                           *)
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(* copy of this software and associated documentation files (the "Software"),*)
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(*****************************************************************************)

open Client_keys

include Tezos_stdlib.Logging.Make(struct let name = "client.signer.ledger" end)

let scheme = "ledger"

let title =
  "Built-in signer using Ledger Nano S."

let description =
  "Valid URIs are of the form\n\
  \ - ledger://<root_pkh>[/<path>]\n\
   where <root_pkh> is the Base58-encoded public key hash of the key \
   at m/44'/1729' and <path> is a BIP32 path anchored at \
   m/44'/1729'. Ledger does not yet support non-hardened path so each \
   node of the path must be hardened.\n\
   Use `tezos-client list connected ledgers` to get the <root_pkh> of \
   all connected devices."

let hard = Int32.logor 0x8000_0000l
let unhard = Int32.logand 0x7fff_ffffl
let is_hard n = Int32.logand 0x8000_0000l n <> 0l
let tezos_root = [hard 44l ; hard 1729l]

module Bip32_path = struct
  let node_of_string str =
    match Int32.of_string_opt str with
    | Some node -> Some node
    | None ->
        match Int32.of_string_opt String.(sub str 0 ((length str) - 1)) with
        | None -> None
        | Some node -> Some (hard node)

  let node_of_string_exn str =
    match node_of_string str with
    | None ->
        invalid_arg (Printf.sprintf "node_of_string_exn: got %S" str)
    | Some str -> str

  let pp_node ppf node =
    match is_hard node with
    | true -> Fmt.pf ppf "%ld'" (unhard node)
    | false -> Fmt.pf ppf "%ld" node

  let string_of_node = Fmt.to_to_string pp_node

  let path_of_string_exn s =
    match String.split_on_char '/' s with
    | [""] -> []
    | nodes ->
        List.map node_of_string_exn nodes

  let path_of_string s =
    try Some (path_of_string_exn s) with _ -> None

  let pp_path =
    Fmt.(list ~sep:(const char '/') pp_node)

  let string_of_path = Fmt.to_to_string pp_path
end

(* Those are always valid on Ledger Nano S with latest firmware. *)
let vendor_id = 0x2c97
let product_id = 0x0001

let pks : (pk_uri, Signature.Public_key.t) Hashtbl.t =
  Hashtbl.create 13

let pkhs : (pk_uri, Signature.Public_key_hash.t) Hashtbl.t =
  Hashtbl.create 13

let curve_of_pkh :
  Signature.public_key_hash -> Ledgerwallet_tezos.curve = function
  | Ed25519 _ -> Ledgerwallet_tezos.Ed25519
  | Secp256k1 _ -> Secp256k1
  | P256 _ -> Secp256r1

let secp256k1_ctx =
  Libsecp256k1.External.Context.create ~sign:false ~verify:false ()

type error +=
  | LedgerError of Ledgerwallet.Transport.error

let error_encoding =
  let open Data_encoding in
  conv
    (fun e -> Format.asprintf "%a" Ledgerwallet.Transport.pp_error e)
    (fun _ ->invalid_arg "Ledger error is not deserializable")
    (obj1 (req "ledger-error" string))

let () =
  register_error_kind
    `Permanent
    ~id: "signer.ledger"
    ~title: "Ledger error"
    ~description: "Error when communication to a Ledger Nano S device"
    ~pp:(fun ppf e ->
        Format.fprintf ppf "Ledger %a" Ledgerwallet.Transport.pp_error e)
    error_encoding
    (function LedgerError e -> Some e | _ -> None)
    (fun e -> LedgerError e)

type id =
  | Animals of Ledger_names.t * Ledgerwallet_tezos.curve
  | Pkh of Signature.Public_key_hash.t

let pp_id ppf = function
  | Pkh pkh -> Signature.Public_key_hash.pp ppf pkh
  | Animals (cthd, curve) ->
      Format.fprintf ppf "%a/%a" Ledger_names.pp cthd
        Ledgerwallet_tezos.pp_curve curve

let parse_animals animals =
  match String.split '-' animals with
  | [c; t; h; d] -> Some { Ledger_names.c ; t ; h ; d }
  | _ -> None

let id_of_uri uri =
  let host = Uri.host uri in
  match Option.apply host
          ~f:Signature.Public_key_hash.of_b58check_opt with
  | Some pkh -> return (Pkh pkh)
  | None ->
      match Option.apply host ~f:parse_animals,
            Option.apply (List.hd_opt (String.split '/' (Uri.path uri)))
              ~f:Ledgerwallet_tezos.curve_of_string with
      | Some animals, Some curve ->
          return (Animals (animals, curve))
      | _ ->
          failwith "No public key hash or animal names in %a"
            Uri.pp_hum uri

let id_of_pk_uri (uri : pk_uri) = id_of_uri (uri :> Uri.t)
let id_of_sk_uri (uri : sk_uri) = id_of_uri (uri :> Uri.t)

let wrap_ledger_cmd f =
  let buf = Buffer.create 100 in
  let pp = Format.formatter_of_buffer buf in
  let res = f pp in
  debug "%s" (Buffer.contents buf) ;
  match res with
  | Error err ->
      fail (LedgerError err)
  | Ok v ->
      return v

let get_public_key
    ?(authorize_baking=false)
    ?(prompt=false)
    ledger curve path =
  let path = tezos_root @ path in
  begin match authorize_baking with
    | false -> wrap_ledger_cmd begin fun pp ->
        Ledgerwallet_tezos.get_public_key ~prompt ~pp ledger curve path
      end
    | true ->
        wrap_ledger_cmd begin fun pp ->
          Ledgerwallet_tezos.authorize_baking ~pp ledger curve path
        end
  end >>|? fun pk ->
  let pk = Cstruct.to_bigarray pk in
  match curve with
  | Ledgerwallet_tezos.Ed25519 ->
      MBytes.set_int8 pk 0 0 ; (* hackish, but works. *)
      Data_encoding.Binary.of_bytes_exn Signature.Public_key.encoding pk
  | Secp256k1 ->
      let open Libsecp256k1.External in
      let buf = MBytes.create (Key.compressed_pk_bytes + 1) in
      let pk = Key.read_pk_exn secp256k1_ctx pk in
      MBytes.set_int8 buf 0 1 ;
      let _nb_written = Key.write secp256k1_ctx ~pos:1 buf pk in
      Data_encoding.Binary.of_bytes_exn Signature.Public_key.encoding buf
  | Secp256r1 ->
      let open Uecc in
      let pklen = compressed_size secp256r1 in
      let buf = MBytes.create (pklen + 1) in
      match pk_of_bytes secp256r1 pk with
      | None ->
          Pervasives.failwith "Impossible to read P256 public key from Ledger"
      | Some pk ->
          MBytes.set_int8 buf 0 2 ;
          let _nb_written = write_key ~compress:true (MBytes.sub buf 1 pklen) pk in
          Data_encoding.Binary.of_bytes_exn Signature.Public_key.encoding buf

module Ledger = struct
  type t = {
    device_info : Hidapi.device_info ;
    version : Ledgerwallet_tezos.Version.t ;
    git_commit : string option ;
    of_curve : (Ledgerwallet_tezos.curve *
                (Signature.Public_key.t *
                 Signature.Public_key_hash.t)) list ;
    of_pkh : (Signature.Public_key_hash.t *
              (Signature.Public_key.t *
               Ledgerwallet_tezos.curve)) list ;
  }

  let create ?git_commit ~device_info ~version ~of_curve ~of_pkh () =
    { device_info ; version ; git_commit ; of_curve ; of_pkh }

  let curves { Ledgerwallet_tezos.Version.major ; minor ; patch ; _ } =
    let open Ledgerwallet_tezos in
    if (major, minor, patch) <= (0, 1, 0) then
      [ Ed25519 ; Secp256k1 ]
    else
      [ Ed25519 ; Secp256k1 ; Secp256r1 ]

  let animals_of_pkh pkh =
    pkh |> Signature.Public_key_hash.to_string |>
    Ledger_names.crouching_tiger

  let find_ledgers ?id ?git_commit h device_info version =
    fold_left_s begin fun (ledger_found, of_curve, of_pkh) curve ->
      get_public_key h curve [] >>|? fun pk ->
      let cur_pkh = Signature.Public_key.hash pk in
      let cur_animals = animals_of_pkh cur_pkh in
      log_info "Found PK: %a" Signature.Public_key.pp pk ;
      log_info "Found PKH: %a" Signature.Public_key_hash.pp cur_pkh ;
      log_info "Found Animals: %a" Ledger_names.pp cur_animals ;
      ledger_found ||
      (match id with
       | Some (Pkh pkh) when pkh = cur_pkh -> true
       | Some (Animals (animals, _)) when animals = cur_animals -> true
       | _ -> false),
      (curve, (pk, cur_pkh)) :: of_curve,
      (cur_pkh, (pk, curve)) :: of_pkh
    end (false, [], []) (curves version)
    >>=? fun (ledger_found, of_curve, of_pkh) ->
    match id with
    | None ->
        return_some
          (create ?git_commit ~device_info ~version
             ~of_curve ~of_pkh ())
    | Some _ when ledger_found ->
        return_some
          (create ?git_commit ~device_info ~version
             ~of_curve ~of_pkh ())
    | _ -> return None

  let of_hidapi ?id device_info h =
    let buf = Buffer.create 100 in
    let pp = Format.formatter_of_buffer buf in
    let version = Ledgerwallet_tezos.get_version ~pp h in
    debug "%s" (Buffer.contents buf) ;
    match version with
    | Error (AppError { status = Ledgerwallet.Transport.Status.Ins_not_supported ; _ })
    | Error (AppError { status = Ledgerwallet_tezos.Version.Tezos_impossible_to_read_version ; _ }) ->
        (* version is < 0.1.1. Assume it is 0.0.1, Tezos app. *)
        let version =
          { Ledgerwallet_tezos.Version.app_class = Tezos ;
            major = 0 ;
            minor = 0 ;
            patch = 1 ;
          } in
        warn "Impossible to read Tezos version, assuming %a"
          Ledgerwallet_tezos.Version.pp version ;
        find_ledgers ?id h device_info version
    | Error e ->
        warn "WARNING:@ The device at [%s] is not a Tezos application@ \
              %a"
          device_info.Hidapi.path
          Ledgerwallet.Transport.pp_error e ;
        return None
    | Ok ({ major; minor; patch; _ } as version) ->
        log_info "Found a %a application at [%s]"
          Ledgerwallet_tezos.Version.pp version device_info.path ;
        begin
          if (major, minor, patch) >= (1, 4, 0) then
            wrap_ledger_cmd (fun pp ->
                Ledgerwallet_tezos.get_git_commit ~pp h) >>=? fun c ->
            return_some c
          else return_none
        end >>=? fun git_commit ->
        find_ledgers ?id ?git_commit h device_info version
end

let find_ledgers ?id () =
  let ledgers = Hidapi.enumerate ~vendor_id ~product_id () in
  log_info "Found %d Ledger(s)" (List.length ledgers) ;
  filter_map_s begin fun device_info ->
    log_info "Processing Ledger at path [%s]" device_info.Hidapi.path ;
    if device_info.Hidapi.interface_number <> 0
    then
      (* HID interfaces get number 0:
         https://github.com/LedgerHQ/ledger-nano-s/issues/48 *)
      return_none
    else
      match Hidapi.(open_path device_info.path) with
      | None -> return_none
      | Some h ->
          Lwt.finalize
            (fun () -> Ledger.of_hidapi ?id device_info h)
            (fun () -> Hidapi.close h ; Lwt.return_unit)
  end ledgers

let with_ledger id f =
  find_ledgers ~id () >>=? function
  | [] ->
      failwith "No Ledger found for %a" pp_id id
  | { device_info ; version ; of_curve ; of_pkh ; _ } :: _ ->
      match Hidapi.open_path device_info.path with
      | None ->
          failwith "Cannot open Ledger %a at path %s"
            pp_id id device_info.path
      | Some h ->
          Lwt.finalize
            (fun () -> f h version of_curve of_pkh)
            (fun () -> Hidapi.close h; Lwt.return_unit)

let int32_of_path_element x =
  match Int32.of_string_opt x with
  | Some i -> Some i
  | None ->
      let len = String.length x in
      if len < 2 then None else
        Option.map
          ~f:hard (Int32.of_string_opt (String.sub x 0 (len - 1)))

let int32_of_path_element_exn x =
  match int32_of_path_element x with
  | None -> invalid_arg "int32_of_path_element_exn"
  | Some p -> p

let neuterize (sk : sk_uri) = return (make_pk_uri (sk :> Uri.t))

let path_of_sk_uri (uri : sk_uri) =
  match TzString.split_path (Uri.path (uri :> Uri.t)) with
  | [] -> []
  | curve :: path when Ledgerwallet_tezos.curve_of_string curve <> None ->
      List.map int32_of_path_element_exn path
  | path -> List.map int32_of_path_element_exn path

let path_of_pk_uri (uri : pk_uri) =
  match TzString.split_path (Uri.path (uri :> Uri.t)) with
  | [] -> []
  | curve :: path when Ledgerwallet_tezos.curve_of_string curve <> None ->
      List.map int32_of_path_element_exn path
  | path -> List.map int32_of_path_element_exn path

let public_key (pk_uri : pk_uri) =
  let find_ledger of_pkh = function
    | Pkh pkh -> snd (List.assoc pkh of_pkh)
    | Animals (_, curve) -> curve
  in
  match Hashtbl.find_opt pks pk_uri with
  | Some pk -> return pk
  | None ->
      id_of_pk_uri pk_uri >>=? fun id ->
      with_ledger id begin fun ledger _version _of_curve of_pkh  ->
        let curve = find_ledger of_pkh id in
        let path = path_of_pk_uri pk_uri in
        get_public_key ledger curve path >>=? fun pk ->
        let pkh = Signature.Public_key.hash pk in
        Hashtbl.replace pks pk_uri pk ;
        Hashtbl.replace pkhs pk_uri pkh ;
        return pk
      end >>= function
      | Error err -> failwith "%a" pp_print_error err
      | Ok v -> return v

let public_key_hash pk_uri =
  match Hashtbl.find_opt pkhs pk_uri with
  | Some pkh -> return (pkh, None)
  | None ->
      public_key pk_uri >>=? fun pk ->
      return (Hashtbl.find pkhs pk_uri, Some pk)

let curve_of_id = function
  | Pkh pkh -> curve_of_pkh pkh
  | Animals (_, curve) -> curve

let sign ?watermark sk_uri msg =
  id_of_sk_uri sk_uri >>=? fun id ->
  with_ledger id begin fun ledger { major; minor; patch; _ } _of_curve _of_pkh ->
    let msg = Option.unopt_map watermark
        ~default:msg ~f:begin fun watermark ->
        MBytes.concat "" [Signature.bytes_of_watermark watermark ;
                          msg]
      end in
    let curve = curve_of_id id in
    let path = tezos_root @ path_of_sk_uri sk_uri in
    let msg_len = MBytes.length msg in
    wrap_ledger_cmd begin fun pp ->
      if msg_len > 1024 && (major, minor, patch) < (1, 1, 0) then
        Ledgerwallet_tezos.sign ~hash_on_ledger:false
          ~pp ledger curve path
          (Cstruct.of_bigarray (Blake2B.(to_bytes (hash_bytes [ msg ]))))
      else
        Ledgerwallet_tezos.sign
          ~pp ledger curve path (Cstruct.of_bigarray msg)
    end >>=? fun signature ->
    match curve with
    | Ed25519 ->
        let signature = Cstruct.to_bigarray signature in
        let signature = Ed25519.of_bytes_exn signature in
        return (Signature.of_ed25519 signature)
    | Secp256k1 ->
        (* Remove parity info *)
        Cstruct.(set_uint8 signature 0 (get_uint8 signature 0 land 0xfe)) ;
        let signature = Cstruct.to_bigarray signature in
        let open Libsecp256k1.External in
        let signature = Sign.read_der_exn secp256k1_ctx signature in
        let bytes = Sign.to_bytes secp256k1_ctx signature in
        let signature = Secp256k1.of_bytes_exn bytes in
        return (Signature.of_secp256k1 signature)
    | Secp256r1 ->
        (* Remove parity info *)
        Cstruct.(set_uint8 signature 0 (get_uint8 signature 0 land 0xfe)) ;
        let signature = Cstruct.to_bigarray signature in
        let open Libsecp256k1.External in
        (* We use secp256r1 library to extract P256 DER signature. *)
        let signature = Sign.read_der_exn secp256k1_ctx signature in
        let buf = Sign.to_bytes secp256k1_ctx signature in
        let signature = P256.of_bytes_exn buf in
        return (Signature.of_p256 signature)
  end

let commands =
  let open Clic in
  let group =
    { Clic.name = "ledger" ;
      title = "Commands for managing the connected Ledger Nano S devices" } in
  fun () -> [
      Clic.command ~group
        ~desc: "List supported Ledger Nano S devices connected."
        no_options
        (fixed [ "list" ; "connected" ; "ledgers" ])
        (fun () (cctxt : Client_context.io_wallet) ->
           find_ledgers () >>=? function
           | [] ->
               cctxt#message "No device found." >>= fun () ->
               cctxt#message "Make sure a Ledger Nano S is connected and in the Tezos Wallet app." >>= fun () ->
               return_unit
           | ledgers ->
               iter_s begin fun { Ledger.device_info = { Hidapi.path ;
                                                         manufacturer_string ;
                                                         product_string ; _ } ;
                                  of_curve ; version ; git_commit ; _ } ->
                 let manufacturer = Option.unopt ~default:"(none)" manufacturer_string in
                 let product = Option.unopt ~default:"(none)" product_string in
                 cctxt#message "Found a %a (commit %s) application running on %s %s at [%s]."
                   Ledgerwallet_tezos.Version.pp version
                   (match git_commit with None -> "unknown" | Some c -> c)
                   manufacturer product path >>= fun () ->
                 let of_curve = List.rev of_curve in
                 begin match List.hd_opt of_curve with
                   | None ->
                       failwith "No curve available, upgrade Ledger software"
                   | Some (_, (_, pkh)) ->
                       return (Ledger_names.crouching_tiger
                                 (Signature.Public_key_hash.to_string pkh))
                 end >>=? fun animals ->
                 cctxt#message
                   "@[<v 0>@,To use keys at BIP32 path \
                    m/44'/1729'/0'/0' (default Tezos key path), use \
                    one of@, @[<v 0>%a@]@]"
                   (Format.pp_print_list
                      (fun ppf (curve, _) ->
                         Format.fprintf ppf
                           "tezos-client import secret key \
                            ledger_%s \"ledger://%a/0'/0'\""
                           (Sys.getenv "USER")
                           pp_id (Animals (animals, curve))))
                   of_curve >>= fun () ->
                 return_unit
               end ledgers) ;

      Clic.command ~group
        ~desc: "Show BIP32 derivation at path for Ledger"
        no_options
        (prefixes [ "show" ; "ledger" ; "path" ]
         @@ Client_keys.sk_uri_param
         @@ stop)
        (fun () sk_uri (cctxt : Client_context.io_wallet) ->
           neuterize sk_uri >>=? fun pk_uri ->
           id_of_pk_uri pk_uri >>=? fun id ->
           find_ledgers ~id () >>=? function
           | [] ->
               failwith "No ledger found for %a" pp_id id
           | { Ledger.device_info ; version ; _ } :: _ ->
               let manufacturer =
                 Option.unopt ~default:"(none)" device_info.manufacturer_string in
               let product =
                 Option.unopt ~default:"(none)" device_info.product_string in
               cctxt#message "Found a valid Tezos application running on %s %s at [%s]."
                 manufacturer product device_info.path >>= fun () ->
               public_key pk_uri >>=? fun pk ->
               public_key_hash pk_uri >>=? fun (pkh, _) ->
               let pkh_bytes = Signature.Public_key_hash.to_bytes pkh in
               match version.app_class with
               | TezBake -> return_unit
               | Tezos ->
                   sign ~watermark:Generic_operation
                     sk_uri pkh_bytes >>=? fun signature ->
                   match Signature.check ~watermark:Generic_operation
                           pk signature pkh_bytes with
                   | false ->
                       failwith "Fatal: Ledger cannot sign with %a"
                         Signature.Public_key_hash.pp pkh
                   | true ->
                       cctxt#message
                         "@[<v 0>Tezos address at this path: %a@,\
                          Corresponding full public key: %a@]"
                         Signature.Public_key_hash.pp pkh
                         Signature.Public_key.pp pk >>= fun () ->
                       return_unit
        ) ;

      Clic.command ~group
        ~desc: "Query the path of the authorized key"
        no_options
        (prefixes [ "get" ; "ledger" ; "authorized" ; "path" ; "for" ]
         @@ Public_key.alias_param
         @@ stop)
        (fun () (name, (pk_uri, _)) (cctxt : Client_context.io_wallet) ->
           id_of_pk_uri pk_uri >>=? fun root_id ->
           with_ledger root_id begin fun h _version _of_curve _to_curve ->
             wrap_ledger_cmd begin fun pp ->
               Ledgerwallet_tezos.get_authorized_key ~pp h
             end >>=? function
             | [] ->
                 cctxt#message
                   "@[<v 0>No baking key authorized for %s@]" name
                 >>= fun () ->
                 return_unit
             | path ->
                 cctxt#message
                   "@[<v 0>Authorized baking path: %a@]"
                   Bip32_path.pp_path path >>= fun () ->
                 return_unit
           end) ;

      Clic.command ~group
        ~desc: "Authorize a Ledger to bake for a key"
        no_options
        (prefixes [ "authorize" ; "ledger" ; "to" ; "bake" ; "for" ]
         @@ Public_key.alias_param
         @@ stop)
        (fun () (_, (pk_uri, _)) (cctxt : Client_context.io_wallet) ->
           id_of_pk_uri pk_uri >>=? fun root_id ->
           with_ledger root_id begin fun h _version _of_curve _of_pkh ->
             let path = path_of_pk_uri pk_uri in
             let curve = curve_of_id root_id in
             get_public_key ~authorize_baking:true h curve path >>=? fun pk ->
             let pkh = Signature.Public_key.hash pk in
             cctxt#message
               "@[<v 0>Authorized baking for address: %a@,\
                Corresponding full public key: %a@]"
               Signature.Public_key_hash.pp pkh
               Signature.Public_key.pp pk >>= fun () ->
             return_unit
           end) ;

      Clic.command ~group
        ~desc: "Get high water mark of a Ledger"
        no_options
        (prefixes [ "get" ; "ledger" ; "high" ; "watermark" ; "for" ]
         @@ Client_keys.sk_uri_param
         @@ stop)
        (fun () sk_uri (cctxt : Client_context.io_wallet) ->
           id_of_sk_uri sk_uri >>=? fun id ->
           with_ledger id begin fun h version _ _ ->
             match version.app_class with
             | Tezos ->
                 failwith "Fatal: this operation is only valid with TezBake"
             | TezBake ->
                 wrap_ledger_cmd begin fun pp ->
                   Ledgerwallet_tezos.get_high_watermark ~pp h
                 end >>=? fun hwm ->
                 cctxt#message
                   "@[<v 0>%a has high water mark: %ld@]"
                   pp_id id hwm >>= fun () ->
                 return_unit
           end
        ) ;

      Clic.command ~group
        ~desc: "Set high water mark of a Ledger"
        no_options
        (prefixes [ "set" ; "ledger" ; "high" ; "watermark" ; "for" ]
         @@ Client_keys.sk_uri_param
         @@ (prefix "to")
         @@ (param
               ~name: "high watermark"
               ~desc: "High watermark"
               (parameter (fun _ctx s ->
                    try return (Int32.of_string s)
                    with _ -> failwith "%s is not an int32 value" s)))
         @@ stop)
        (fun () sk_uri hwm (cctxt : Client_context.io_wallet) ->
           id_of_sk_uri sk_uri >>=? fun id ->
           with_ledger id begin fun h version _ _ ->
             match version.app_class with
             | Tezos ->
                 failwith "Fatal: this operation is only valid with TezBake"
             | TezBake ->
                 wrap_ledger_cmd begin fun pp ->
                   Ledgerwallet_tezos.set_high_watermark ~pp h hwm
                 end >>=? fun () ->
                 wrap_ledger_cmd begin fun pp ->
                   Ledgerwallet_tezos.get_high_watermark ~pp h
                 end >>=? fun new_hwm ->
                 cctxt#message
                   "@[<v 0>%a has now high water mark: %ld@]"
                   pp_id id new_hwm >>= fun () ->
                 return_unit
           end
        ) ;
    ]