nixpkgs/upstart-jobs/portmap.nix

{pkgs, config, ...}:

###### interface
let
  inherit (pkgs.lib) mkOption mkIf;
  inherit (pkgs) makePortmap;

  uid = (import ../system/ids.nix).uids.portmap;
  gid = (import ../system/ids.nix).gids.portmap;

  options = {
    services = {
      portmap = {

        enable = mkOption {
          default = false;
          description = ''
            Whether to enable `portmap', an ONC RPC directory service
            notably used by NFS and NIS, and which can be queried
            using the rpcinfo(1) command.
          '';
        };

        verbose = mkOption {
          default = false;
          description = ''
            Whether to enable verbose output.
          '';
        };

        chroot = mkOption {
          default = "/var/empty";
          description = ''
            If non-empty, a path to change root to.
          '';
        };

      };
    };
  };

in

###### implementation
mkIf config.services.portmap.enable {
  require = [
    options
  ];
  
  users = {
    extraUsers = [
      { name = "portmap";
        inherit uid;
        description = "portmap daemon user";
        home = "/var/empty";
      }
    ];

    extraGroups = [
      { name = "portmap";
        inherit gid;
      }
    ];
  };

  services = {
    extraJobs = [{
      name = "portmap";

      job =
        let portmap = makePortmap { daemonUID = uid; daemonGID = gid; };
        in ''
          description "ONC RPC portmap"

          start on network-interfaces/started
          stop on network-interfaces/stop

          respawn ${portmap}/sbin/portmap \
            ${if config.services.portmap.chroot == ""
              then ""
              else "-t \"${config.services.portmap.chroot}\""} \
            ${if config.services.portmap.verbose then "-v" else ""}
        '';
    }];
  };
}