Some display managers (e.g. SDDM) set the XDG_CURRENT_DESKTOP variable accroding to this parameter. If this variable is not defined, there will be some problems (e.g. MATE doesn't have icons on the desktop). Fixes https://github.com/NixOS/nixpkgs/issues/71427
		
			
				
	
	
		
			449 lines
		
	
	
		
			16 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
			
		
		
	
	
			449 lines
		
	
	
		
			16 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
# This module declares the options to define a *display manager*, the
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# program responsible for handling X logins (such as LightDM, GDM, or SDDM).
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# The display manager allows the user to select a *session
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# type*. When the user logs in, the display manager starts the
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# *session script* ("xsession" below) to launch the selected session
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# type. The session type defines two things: the *desktop manager*
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# (e.g., KDE, Gnome or a plain xterm), and optionally the *window
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# manager* (e.g. kwin or twm).
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{ config, lib, pkgs, ... }:
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with lib;
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let
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  cfg = config.services.xserver;
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  xorg = pkgs.xorg;
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  fontconfig = config.fonts.fontconfig;
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  xresourcesXft = pkgs.writeText "Xresources-Xft" ''
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    ${optionalString (fontconfig.dpi != 0) ''Xft.dpi: ${toString fontconfig.dpi}''}
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    Xft.antialias: ${if fontconfig.antialias then "1" else "0"}
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    Xft.rgba: ${fontconfig.subpixel.rgba}
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    Xft.lcdfilter: lcd${fontconfig.subpixel.lcdfilter}
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    Xft.hinting: ${if fontconfig.hinting.enable then "1" else "0"}
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    Xft.autohint: ${if fontconfig.hinting.autohint then "1" else "0"}
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    Xft.hintstyle: hintslight
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  '';
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  # file provided by services.xserver.displayManager.sessionData.wrapper
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  xsessionWrapper = pkgs.writeScript "xsession-wrapper"
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    ''
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      #! ${pkgs.bash}/bin/bash
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      # Shared environment setup for graphical sessions.
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      . /etc/profile
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      cd "$HOME"
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      ${optionalString cfg.startDbusSession ''
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        if test -z "$DBUS_SESSION_BUS_ADDRESS"; then
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          exec ${pkgs.dbus.dbus-launch} --exit-with-session "$0" "$@"
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        fi
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      ''}
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      ${optionalString cfg.displayManager.job.logToJournal ''
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        if [ -z "$_DID_SYSTEMD_CAT" ]; then
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          export _DID_SYSTEMD_CAT=1
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          exec ${config.systemd.package}/bin/systemd-cat -t xsession "$0" "$@"
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        fi
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      ''}
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      ${optionalString cfg.displayManager.job.logToFile ''
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        exec &> >(tee ~/.xsession-errors)
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      ''}
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      # Start PulseAudio if enabled.
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      ${optionalString (config.hardware.pulseaudio.enable) ''
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        # Publish access credentials in the root window.
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        if ${config.hardware.pulseaudio.package.out}/bin/pulseaudio --dump-modules | grep module-x11-publish &> /dev/null; then
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          ${config.hardware.pulseaudio.package.out}/bin/pactl load-module module-x11-publish "display=$DISPLAY"
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        fi
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      ''}
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      # Tell systemd about our $DISPLAY and $XAUTHORITY.
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      # This is needed by the ssh-agent unit.
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      #
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      # Also tell systemd about the dbus session bus address.
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      # This is required by user units using the session bus.
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      ${config.systemd.package}/bin/systemctl --user import-environment DISPLAY XAUTHORITY DBUS_SESSION_BUS_ADDRESS
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      # Load X defaults. This should probably be safe on wayland too.
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      ${xorg.xrdb}/bin/xrdb -merge ${xresourcesXft}
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      if test -e ~/.Xresources; then
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          ${xorg.xrdb}/bin/xrdb -merge ~/.Xresources
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      elif test -e ~/.Xdefaults; then
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          ${xorg.xrdb}/bin/xrdb -merge ~/.Xdefaults
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      fi
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      # Speed up application start by 50-150ms according to
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      # http://kdemonkey.blogspot.nl/2008/04/magic-trick.html
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      rm -rf "$HOME/.compose-cache"
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      mkdir "$HOME/.compose-cache"
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      # Work around KDE errors when a user first logs in and
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      # .local/share doesn't exist yet.
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      mkdir -p "$HOME/.local/share"
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      unset _DID_SYSTEMD_CAT
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      ${cfg.displayManager.sessionCommands}
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      # Allow the user to execute commands at the beginning of the X session.
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      if test -f ~/.xprofile; then
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          source ~/.xprofile
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      fi
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      # Start systemd user services for graphical sessions
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      ${config.systemd.package}/bin/systemctl --user start graphical-session.target
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      # Allow the user to setup a custom session type.
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      if test -x ~/.xsession; then
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          eval exec ~/.xsession "$@"
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      fi
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      if test "$1"; then
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          # Run the supplied session command. Remove any double quotes with eval.
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          eval exec "$@"
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      else
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          # TODO: Do we need this? Should not the session always exist?
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          echo "error: unknown session $1" 1>&2
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          exit 1
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      fi
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    '';
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  installedSessions = pkgs.runCommand "desktops"
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    { # trivial derivation
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      preferLocalBuild = true;
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      allowSubstitutes = false;
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    }
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    ''
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      mkdir -p "$out/share/"{xsessions,wayland-sessions}
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      ${concatMapStrings (pkg: ''
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        for n in ${concatStringsSep " " pkg.providedSessions}; do
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          if ! test -f ${pkg}/share/wayland-sessions/$n.desktop -o \
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                    -f ${pkg}/share/xsessions/$n.desktop; then
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            echo "Couldn't find provided session name, $n.desktop, in session package ${pkg.name}:"
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            echo "  ${pkg}"
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            return 1
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          fi
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        done
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        if test -d ${pkg}/share/xsessions; then
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          ${xorg.lndir}/bin/lndir ${pkg}/share/xsessions $out/share/xsessions
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        fi
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        if test -d ${pkg}/share/wayland-sessions; then
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          ${xorg.lndir}/bin/lndir ${pkg}/share/wayland-sessions $out/share/wayland-sessions
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        fi
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      '') cfg.displayManager.sessionPackages}
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    '';
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  dmDefault = cfg.desktopManager.default;
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  # fallback default for cases when only default wm is set
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  dmFallbackDefault = if dmDefault != null then dmDefault else "none";
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  wmDefault = cfg.windowManager.default;
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  defaultSessionFromLegacyOptions = dmFallbackDefault + optionalString (wmDefault != null && wmDefault != "none") "+${wmDefault}";
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in
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{
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  options = {
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    services.xserver.displayManager = {
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      xauthBin = mkOption {
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        internal = true;
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        default = "${xorg.xauth}/bin/xauth";
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        description = "Path to the <command>xauth</command> program used by display managers.";
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      };
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      xserverBin = mkOption {
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        type = types.path;
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        description = "Path to the X server used by display managers.";
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      };
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      xserverArgs = mkOption {
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        type = types.listOf types.str;
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        default = [];
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        example = [ "-ac" "-logverbose" "-verbose" "-nolisten tcp" ];
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        description = "List of arguments for the X server.";
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      };
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      setupCommands = mkOption {
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        type = types.lines;
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        default = "";
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        description = ''
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          Shell commands executed just after the X server has started.
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          This option is only effective for display managers for which this feature
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          is supported; currently these are LightDM, GDM and SDDM.
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        '';
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      };
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      sessionCommands = mkOption {
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        type = types.lines;
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        default = "";
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        example =
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          ''
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            xmessage "Hello World!" &
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          '';
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        description = ''
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          Shell commands executed just before the window or desktop manager is
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          started. These commands are not currently sourced for Wayland sessions.
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        '';
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      };
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      hiddenUsers = mkOption {
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        type = types.listOf types.str;
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        default = [ "nobody" ];
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        description = ''
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          A list of users which will not be shown in the display manager.
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        '';
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      };
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      sessionPackages = mkOption {
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        type = with types; listOf (package // {
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          description = "package with provided sessions";
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          check = p: assertMsg
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            (package.check p && p ? providedSessions
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            && p.providedSessions != [] && all isString p.providedSessions)
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            ''
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              Package, '${p.name}', did not specify any session names, as strings, in
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              'passthru.providedSessions'. This is required when used as a session package.
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              The session names can be looked up in:
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                ${p}/share/xsessions
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                ${p}/share/wayland-sessions
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           '';
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        });
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        default = [];
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        description = ''
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          A list of packages containing x11 or wayland session files to be passed to the display manager.
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        '';
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      };
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      session = mkOption {
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        default = [];
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        example = literalExample
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          ''
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            [ { manage = "desktop";
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                name = "xterm";
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                start = '''
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                  ''${pkgs.xterm}/bin/xterm -ls &
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                  waitPID=$!
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                ''';
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              }
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            ]
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          '';
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        description = ''
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          List of sessions supported with the command used to start each
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          session.  Each session script can set the
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          <varname>waitPID</varname> shell variable to make this script
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          wait until the end of the user session.  Each script is used
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          to define either a window manager or a desktop manager.  These
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          can be differentiated by setting the attribute
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          <varname>manage</varname> either to <literal>"window"</literal>
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          or <literal>"desktop"</literal>.
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          The list of desktop manager and window manager should appear
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          inside the display manager with the desktop manager name
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          followed by the window manager name.
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        '';
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      };
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      sessionData = mkOption {
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        description = "Data exported for display managers’ convenience";
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        internal = true;
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        default = {};
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        apply = val: {
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          wrapper = xsessionWrapper;
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          desktops = installedSessions;
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          sessionNames = concatMap (p: p.providedSessions) cfg.displayManager.sessionPackages;
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          # We do not want to force users to set defaultSession when they have only single DE.
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          autologinSession =
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            if cfg.displayManager.defaultSession != null then
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              cfg.displayManager.defaultSession
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            else if cfg.displayManager.sessionData.sessionNames != [] then
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              head cfg.displayManager.sessionData.sessionNames
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            else
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              null;
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        };
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      };
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      defaultSession = mkOption {
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        type = with types; nullOr str // {
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          description = "session name";
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          check = d:
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            assertMsg (d != null -> (str.check d && elem d cfg.displayManager.sessionData.sessionNames)) ''
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                Default graphical session, '${d}', not found.
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                Valid names for 'services.xserver.displayManager.defaultSession' are:
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                  ${concatStringsSep "\n  " cfg.displayManager.sessionData.sessionNames}
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              '';
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        };
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        default =
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          if dmDefault != null || wmDefault != null then
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            defaultSessionFromLegacyOptions
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          else
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            null;
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        example = "gnome";
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        description = ''
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          Graphical session to pre-select in the session chooser (only effective for GDM and LightDM).
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          On GDM, LightDM and SDDM, it will also be used as a session for auto-login.
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        '';
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      };
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      job = {
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        preStart = mkOption {
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          type = types.lines;
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          default = "";
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          example = "rm -f /var/log/my-display-manager.log";
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          description = "Script executed before the display manager is started.";
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        };
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        execCmd = mkOption {
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          type = types.str;
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          example = literalExample ''
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            "''${pkgs.lightdm}/bin/lightdm"
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          '';
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          description = "Command to start the display manager.";
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        };
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        environment = mkOption {
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          type = types.attrsOf types.unspecified;
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          default = {};
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          description = "Additional environment variables needed by the display manager.";
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        };
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        logToFile = mkOption {
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          type = types.bool;
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          default = false;
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          description = ''
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            Whether the display manager redirects the output of the
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            session script to <filename>~/.xsession-errors</filename>.
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          '';
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        };
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        logToJournal = mkOption {
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          type = types.bool;
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          default = true;
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          description = ''
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            Whether the display manager redirects the output of the
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            session script to the systemd journal.
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          '';
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        };
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      };
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    };
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  };
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  config = {
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    assertions = [
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      {
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        assertion = cfg.desktopManager.default != null || cfg.windowManager.default != null -> cfg.displayManager.defaultSession == defaultSessionFromLegacyOptions;
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        message = "You cannot use both services.xserver.displayManager.defaultSession option and legacy options (services.xserver.desktopManager.default and services.xserver.windowManager.default).";
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      }
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    ];
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    warnings =
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      mkIf (dmDefault != null || wmDefault != null) [
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        ''
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          The following options are deprecated:
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            ${concatStringsSep "\n  " (map ({c, t}: t) (filter ({c, t}: c != null) [
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            { c = dmDefault; t = "- services.xserver.desktopManager.default"; }
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            { c = wmDefault; t = "- services.xserver.windowManager.default"; }
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            ]))}
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          Please use
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            services.xserver.displayManager.defaultSession = "${defaultSessionFromLegacyOptions}";
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          instead.
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        ''
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						||
      ];
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    services.xserver.displayManager.xserverBin = "${xorg.xorgserver.out}/bin/X";
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 | 
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    systemd.user.targets.graphical-session = {
 | 
						||
      unitConfig = {
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        RefuseManualStart = false;
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        StopWhenUnneeded = false;
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      };
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						||
    };
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    # Create desktop files and scripts for starting sessions for WMs/DMs
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						||
    # that do not have upstream session files (those defined using services.{display,desktop,window}Manager.session options).
 | 
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    services.xserver.displayManager.sessionPackages =
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      let
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        dms = filter (s: s.manage == "desktop") cfg.displayManager.session;
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        wms = filter (s: s.manage == "window") cfg.displayManager.session;
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 | 
						||
        # Script responsible for starting the window manager and the desktop manager.
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						||
        xsession = dm: wm: pkgs.writeScript "xsession" ''
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          #! ${pkgs.bash}/bin/bash
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						||
 | 
						||
          # Legacy session script used to construct .desktop files from
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						||
          # `services.xserver.displayManager.session` entries. Called from
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						||
          # `sessionWrapper`.
 | 
						||
 | 
						||
          # Start the window manager.
 | 
						||
          ${wm.start}
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						||
 | 
						||
          # Start the desktop manager.
 | 
						||
          ${dm.start}
 | 
						||
 | 
						||
          ${optionalString cfg.updateDbusEnvironment ''
 | 
						||
            ${lib.getBin pkgs.dbus}/bin/dbus-update-activation-environment --systemd --all
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          ''}
 | 
						||
 | 
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          test -n "$waitPID" && wait "$waitPID"
 | 
						||
 | 
						||
          ${config.systemd.package}/bin/systemctl --user stop graphical-session.target
 | 
						||
 | 
						||
          exit 0
 | 
						||
        '';
 | 
						||
      in
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        # We will generate every possible pair of WM and DM.
 | 
						||
        concatLists (
 | 
						||
          crossLists
 | 
						||
            (dm: wm: let
 | 
						||
              sessionName = "${dm.name}${optionalString (wm.name != "none") ("+" + wm.name)}";
 | 
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              script = xsession dm wm;
 | 
						||
            in
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              optional (dm.name != "none" || wm.name != "none")
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                (pkgs.writeTextFile {
 | 
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                  name = "${sessionName}-xsession";
 | 
						||
                  destination = "/share/xsessions/${sessionName}.desktop";
 | 
						||
                  # Desktop Entry Specification:
 | 
						||
                  # - https://standards.freedesktop.org/desktop-entry-spec/latest/
 | 
						||
                  # - https://standards.freedesktop.org/desktop-entry-spec/latest/ar01s06.html
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                  text = ''
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                    [Desktop Entry]
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                    Version=1.0
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                    Type=XSession
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                    TryExec=${script}
 | 
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                    Exec=${script}
 | 
						||
                    Name=${sessionName}
 | 
						||
                    DesktopNames=${sessionName}
 | 
						||
                  '';
 | 
						||
                } // {
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						||
                  providedSessions = [ sessionName ];
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						||
                })
 | 
						||
            )
 | 
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            [dms wms]
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						||
          );
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						||
  };
 | 
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 | 
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  imports = [
 | 
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    (mkRemovedOptionModule [ "services" "xserver" "displayManager" "desktopManagerHandlesLidAndPower" ]
 | 
						||
     "The option is no longer necessary because all display managers have already delegated lid management to systemd.")
 | 
						||
    (mkRenamedOptionModule [ "services" "xserver" "displayManager" "job" "logsXsession" ] [ "services" "xserver" "displayManager" "job" "logToFile" ])
 | 
						||
    (mkRenamedOptionModule [ "services" "xserver" "displayManager" "logToJournal" ] [ "services" "xserver" "displayManager" "job" "logToJournal" ])
 | 
						||
    (mkRenamedOptionModule [ "services" "xserver" "displayManager" "extraSessionFilesPackages" ] [ "services" "xserver" "displayManager" "sessionPackages" ])
 | 
						||
  ];
 | 
						||
 | 
						||
}
 |