nixpkgs/nixos/modules/services/x11/display-managers/lightdm.nix
Jan Tojnar 8dc5ff7dcf
nixos/displayManager: deprecate separate options for default wm/dm
The upstream session files display managers use have no concept of sessions being composed from
desktop manager and window manager. To be able to set upstream session files as default
session, we need a single option. Having two different ways to set default session would be confusing,
though, so we decided to deprecate the old method.

We also created separate script for each session, just like we already had a separate desktop
file for each one, and started using displayManager.sessionPackages mechanism to make the
session handling more uniform.
2019-12-15 04:16:20 +01:00

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{ config, lib, pkgs, ... }:
with lib;
let
xcfg = config.services.xserver;
dmcfg = xcfg.displayManager;
xEnv = config.systemd.services.display-manager.environment;
cfg = dmcfg.lightdm;
sessionData = dmcfg.sessionData;
setSessionScript = pkgs.callPackage ./account-service-util.nix { };
inherit (pkgs) lightdm writeScript writeText;
# lightdm runs with clearenv(), but we need a few things in the environment for X to startup
xserverWrapper = writeScript "xserver-wrapper"
''
#! ${pkgs.bash}/bin/bash
${concatMapStrings (n: "export ${n}=\"${getAttr n xEnv}\"\n") (attrNames xEnv)}
display=$(echo "$@" | xargs -n 1 | grep -P ^:\\d\$ | head -n 1 | sed s/^://)
if [ -z "$display" ]
then additionalArgs=":0 -logfile /var/log/X.0.log"
else additionalArgs="-logfile /var/log/X.$display.log"
fi
exec ${dmcfg.xserverBin} ${toString dmcfg.xserverArgs} $additionalArgs "$@"
'';
usersConf = writeText "users.conf"
''
[UserList]
minimum-uid=500
hidden-users=${concatStringsSep " " dmcfg.hiddenUsers}
hidden-shells=/run/current-system/sw/bin/nologin
'';
lightdmConf = writeText "lightdm.conf"
''
[LightDM]
${optionalString cfg.greeter.enable ''
greeter-user = ${config.users.users.lightdm.name}
greeters-directory = ${cfg.greeter.package}
''}
sessions-directory = ${dmcfg.sessionData.desktops}/share/xsessions:${dmcfg.sessionData.desktops}/share/wayland-sessions
${cfg.extraConfig}
[Seat:*]
xserver-command = ${xserverWrapper}
session-wrapper = ${dmcfg.sessionData.wrapper}
${optionalString cfg.greeter.enable ''
greeter-session = ${cfg.greeter.name}
''}
${optionalString cfg.autoLogin.enable ''
autologin-user = ${cfg.autoLogin.user}
autologin-user-timeout = ${toString cfg.autoLogin.timeout}
autologin-session = ${sessionData.autologinSession}
''}
${optionalString (dmcfg.setupCommands != "") ''
display-setup-script=${pkgs.writeScript "lightdm-display-setup" ''
#!${pkgs.bash}/bin/bash
${dmcfg.setupCommands}
''}
''}
${cfg.extraSeatDefaults}
'';
in
{
# Note: the order in which lightdm greeter modules are imported
# here determines the default: later modules (if enable) are
# preferred.
imports = [
./lightdm-greeters/gtk.nix
./lightdm-greeters/mini.nix
./lightdm-greeters/enso-os.nix
./lightdm-greeters/pantheon.nix
];
options = {
services.xserver.displayManager.lightdm = {
enable = mkOption {
type = types.bool;
default = false;
description = ''
Whether to enable lightdm as the display manager.
'';
};
greeter = {
enable = mkOption {
type = types.bool;
default = true;
description = ''
If set to false, run lightdm in greeterless mode. This only works if autologin
is enabled and autoLogin.timeout is zero.
'';
};
package = mkOption {
type = types.package;
description = ''
The LightDM greeter to login via. The package should be a directory
containing a .desktop file matching the name in the 'name' option.
'';
};
name = mkOption {
type = types.str;
description = ''
The name of a .desktop file in the directory specified
in the 'package' option.
'';
};
};
extraConfig = mkOption {
type = types.lines;
default = "";
example = ''
user-authority-in-system-dir = true
'';
description = "Extra lines to append to LightDM section.";
};
background = mkOption {
type = types.str;
default = "${pkgs.nixos-artwork.wallpapers.simple-dark-gray-bottom}/share/artwork/gnome/nix-wallpaper-simple-dark-gray_bottom.png";
description = ''
The background image or color to use.
'';
};
extraSeatDefaults = mkOption {
type = types.lines;
default = "";
example = ''
greeter-show-manual-login=true
'';
description = "Extra lines to append to SeatDefaults section.";
};
autoLogin = mkOption {
default = {};
description = ''
Configuration for automatic login.
'';
type = types.submodule {
options = {
enable = mkOption {
type = types.bool;
default = false;
description = ''
Automatically log in as the specified <option>autoLogin.user</option>.
'';
};
user = mkOption {
type = types.nullOr types.str;
default = null;
description = ''
User to be used for the automatic login.
'';
};
timeout = mkOption {
type = types.int;
default = 0;
description = ''
Show the greeter for this many seconds before automatic login occurs.
'';
};
};
};
};
};
};
config = mkIf cfg.enable {
assertions = [
{ assertion = xcfg.enable;
message = ''
LightDM requires services.xserver.enable to be true
'';
}
{ assertion = cfg.autoLogin.enable -> cfg.autoLogin.user != null;
message = ''
LightDM auto-login requires services.xserver.displayManager.lightdm.autoLogin.user to be set
'';
}
{ assertion = cfg.autoLogin.enable -> sessionData.autologinSession != null;
message = ''
LightDM auto-login requires that services.xserver.displayManager.defaultSession is set.
'';
}
{ assertion = !cfg.greeter.enable -> (cfg.autoLogin.enable && cfg.autoLogin.timeout == 0);
message = ''
LightDM can only run without greeter if automatic login is enabled and the timeout for it
is set to zero.
'';
}
];
# Set default session in session chooser to a specified values basically ignore session history.
# Auto-login is already covered by a config value.
services.xserver.displayManager.job.preStart = optionalString (!cfg.autoLogin.enable && dmcfg.defaultSession != null) ''
${setSessionScript}/bin/set-session ${dmcfg.defaultSession}
'';
# setSessionScript needs session-files in XDG_DATA_DIRS
services.xserver.displayManager.job.environment.XDG_DATA_DIRS = "${dmcfg.sessionData.desktops}/share/";
# setSessionScript wants AccountsService
systemd.services.display-manager.wants = [
"accounts-daemon.service"
];
# lightdm relaunches itself via just `lightdm`, so needs to be on the PATH
services.xserver.displayManager.job.execCmd = ''
export PATH=${lightdm}/sbin:$PATH
exec ${lightdm}/sbin/lightdm
'';
# Replaces getty
systemd.services.display-manager.conflicts = [
"getty@tty7.service"
# TODO: Add "plymouth-quit.service" so LightDM can control when plymouth
# quits. Currently this breaks switching to configurations with plymouth.
];
# Pull in dependencies of services we replace.
systemd.services.display-manager.after = [
"rc-local.service"
"systemd-machined.service"
"systemd-user-sessions.service"
"getty@tty7.service"
"user.slice"
];
# user.slice needs to be present
systemd.services.display-manager.requires = [
"user.slice"
];
# lightdm stops plymouth so when it fails make sure plymouth stops.
systemd.services.display-manager.onFailure = [
"plymouth-quit.service"
];
systemd.services.display-manager.serviceConfig = {
BusName = "org.freedesktop.DisplayManager";
IgnoreSIGPIPE = "no";
# This allows lightdm to pass the LUKS password through to PAM.
# login keyring is unlocked automatic when autologin is used.
KeyringMode = "shared";
KillMode = "mixed";
StandardError = "inherit";
StandardOutput = "syslog";
};
environment.etc."lightdm/lightdm.conf".source = lightdmConf;
environment.etc."lightdm/users.conf".source = usersConf;
services.dbus.enable = true;
services.dbus.packages = [ lightdm ];
# lightdm uses the accounts daemon to remember language/window-manager per user
services.accounts-daemon.enable = true;
# Enable the accounts daemon to find lightdm's dbus interface
environment.systemPackages = [ lightdm ];
security.pam.services.lightdm.text = ''
auth substack login
account include login
password substack login
session include login
'';
security.pam.services.lightdm-greeter.text = ''
auth required pam_succeed_if.so audit quiet_success user = lightdm
auth optional pam_permit.so
account required pam_succeed_if.so audit quiet_success user = lightdm
account sufficient pam_unix.so
password required pam_deny.so
session required pam_succeed_if.so audit quiet_success user = lightdm
session required pam_env.so conffile=${config.system.build.pamEnvironment} readenv=0
session optional ${pkgs.systemd}/lib/security/pam_systemd.so
session optional pam_keyinit.so force revoke
session optional pam_permit.so
'';
security.pam.services.lightdm-autologin.text = ''
auth requisite pam_nologin.so
auth required pam_succeed_if.so uid >= 1000 quiet
auth required pam_permit.so
account sufficient pam_unix.so
password requisite pam_unix.so nullok sha512
session optional pam_keyinit.so revoke
session include login
'';
users.users.lightdm = {
home = "/var/lib/lightdm";
group = "lightdm";
uid = config.ids.uids.lightdm;
};
systemd.tmpfiles.rules = [
"d /run/lightdm 0711 lightdm lightdm 0"
"d /var/cache/lightdm 0711 root lightdm -"
"d /var/lib/lightdm 1770 lightdm lightdm -"
"d /var/lib/lightdm-data 1775 lightdm lightdm -"
"d /var/log/lightdm 0711 root lightdm -"
];
users.groups.lightdm.gid = config.ids.gids.lightdm;
services.xserver.tty = null; # We might start multiple X servers so let the tty increment themselves..
services.xserver.display = null; # We specify our own display (and logfile) in xserver-wrapper up there
};
}