Merge pull request #260248 from ToxicFrog/linger

          administrator before being able to use the system again.

        '';

      };

      linger = mkOption {

        type = types.bool;

        default = false;

        description = lib.mdDoc ''

          Whether to enable lingering for this user. If true, systemd user

          units will start at boot, rather than starting at login and stopping

          at logout. This is the declarative equivalent of running

          `loginctl enable-linger` for this user.

          If false, user units will not be started until the user logs in, and

          may be stopped on logout depending on the settings in `logind.conf`.

        '';

      };

    };

    config = mkMerge

      '';

    };

    system.activationScripts.update-lingering = let

      lingerDir = "/var/lib/systemd/linger";

      lingeringUsers = map (u: u.name) (attrValues (flip filterAttrs cfg.users (n: u: u.linger)));

      lingeringUsersFile = builtins.toFile "lingering-users"

        (concatStrings (map (s: "${s}\n")

          (sort (a: b: a < b) lingeringUsers)));  # this sorting is important for `comm` to work correctly

    in stringAfter [ "users" ] ''

      if [ -e ${lingerDir} ] ; then

        cd ${lingerDir}

        ls ${lingerDir} | sort | comm -3 -1 ${lingeringUsersFile} - | xargs -r ${pkgs.systemd}/bin/loginctl disable-linger

        ls ${lingerDir} | sort | comm -3 -2 ${lingeringUsersFile} - | xargs -r ${pkgs.systemd}/bin/loginctl  enable-linger

      fi

    '';

    # Warn about user accounts with deprecated password hashing schemes

    system.activationScripts.hashes = {

      deps = [ "users" ];