nixpkgs/modules/security/sudo.nix

{pkgs, config, ...}:

with pkgs.lib;

let

  cfg = config.security.sudo;
  
  inherit (pkgs) sudo;

in

{

  ###### interface

  options = {

    security.sudo.enable = mkOption {
      default = true;
      description =
        ''
          Whether to enable the <command>sudo</command> command, which
          allows non-root users to execute commands as root.
        '';
    };

    security.sudo.configFile = mkOption {
      # Note: if syntax errors are detected in this file, the NixOS
      # configuration will fail to build.
      default =
        ''
          # WARNING: do not edit this file directly or with "visudo".  Instead,
          # edit the source file in /etc/nixos/nixos/etc/sudoers.

          # "root" is allowed to do anything.
          root        ALL=(ALL) SETENV: ALL

          # Users in the "wheel" group can do anything.
          %wheel      ALL=(ALL) SETENV: ALL
        '';
      description =
        ''
          This string contains the contents of the
          <filename>sudoers</filename> file.
        '';
    };
  };


  ###### implementation

  config = mkIf cfg.enable {

    security.extraSetuidPrograms = [ "sudo" ];

    environment.systemPackages = [ sudo ];

    security.pam.services = [ { name = "sudo"; } ];

    environment.etc = singleton
      { source = pkgs.runCommand "sudoers"
          { src = pkgs.writeText "sudoers-in" cfg.configFile; }
          # Make sure that the sudoers file is syntactically valid.
          # (currently disabled - NIXOS-66)
          #"${pkgs.sudo}/sbin/visudo -f $src -c && cp $src $out";
          "cp $src $out";
        target = "sudoers";
        mode = "0440";
      };

  };

}