;;; GNU Guix --- Functional package management for GNU ;;; Copyright © 2019, 2020 L p R n d n ;;; Copyright © 2020 Ricardo Wurmus ;;; Copyright © 2022 Maxim Cournoyer ;;; ;;; This file is part of GNU Guix. ;;; ;;; GNU Guix is free software; you can redistribute it and/or modify it ;;; under the terms of the GNU General Public License as published by ;;; the Free Software Foundation; either version 3 of the License, or (at ;;; your option) any later version. ;;; ;;; GNU Guix is distributed in the hope that it will be useful, but ;;; WITHOUT ANY WARRANTY; without even the implied warranty of ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;;; GNU General Public License for more details. ;;; ;;; You should have received a copy of the GNU General Public License ;;; along with GNU Guix. If not, see . (define-module (gnu services lightdm) #:use-module (gnu artwork) #:use-module (gnu packages admin) #:use-module (gnu packages display-managers) #:use-module (gnu packages freedesktop) #:use-module (gnu packages gnome) #:use-module (gnu packages vnc) #:use-module (gnu packages xorg) #:use-module (gnu services configuration) #:use-module (gnu services dbus) #:use-module (gnu services desktop) #:use-module (gnu services shepherd) #:use-module (gnu services xorg) #:use-module (gnu services) #:use-module (gnu system pam) #:use-module (gnu system shadow) #:use-module (guix diagnostics) #:use-module (guix gexp) #:use-module (guix i18n) #:use-module (guix records) #:use-module (ice-9 format) #:use-module (ice-9 match) #:use-module (srfi srfi-1) #:use-module (srfi srfi-26) #:export (lightdm-seat-configuration lightdm-seat-configuration? lightdm-seat-configuration-name lightdm-seat-configuration-type lightdm-seat-configuration-user-session lightdm-seat-configuration-autologin-user lightdm-seat-configuration-greeter-session lightdm-seat-configuration-xserver-command lightdm-seat-configuration-session-wrapper lightdm-seat-configuration-extra-config lightdm-gtk-greeter-configuration lightdm-gtk-greeter-configuration? lightdm-gtk-greeter-configuration-lightdm-gtk-greeter lightdm-gtk-greeter-configuration-assets lightdm-gtk-greeter-configuration-theme-name lightdm-gtk-greeter-configuration-icon-theme-name lightdm-gtk-greeter-configuration-cursor-theme-name lightdm-gtk-greeter-configuration-allow-debug lightdm-gtk-greeter-configuration-background lightdm-gtk-greeter-configuration-a11y-states lightdm-gtk-greeter-configuration-reader lightdm-gtk-greeter-configuration-extra-config lightdm-configuration lightdm-configuration? lightdm-configuration-lightdm lightdm-configuration-allow-empty-passwords? lightdm-configuration-xorg-configuration lightdm-configuration-greeters lightdm-configuration-seats lightdm-configuration-xdmcp? lightdm-configuration-xdmcp-listen-address lightdm-configuration-vnc-server? lightdm-configuration-vnc-server-command lightdm-configuration-vnc-server-listen-address lightdm-configuration-vnc-server-port lightdm-configuration-extra-config lightdm-service-type)) ;;; ;;; Greeters. ;;; (define list-of-file-likes? (list-of file-like?)) (define %a11y-states '(contrast font keyboard reader)) (define (a11y-state? value) (memq value %a11y-states)) (define list-of-a11y-states? (list-of a11y-state?)) (define-maybe boolean) (define (serialize-boolean name value) (define (strip-trailing-? name) ;; field? -> field (let ((str (symbol->string name))) (if (string-suffix? "?" str) (string-drop-right str 1) str))) (format #f "~a=~:[false~;true~]~%" (strip-trailing-? name) value)) (define-maybe file-like) (define (serialize-file-like name value) #~(format #f "~a=~a~%" '#$name #$value)) (define (serialize-list-of-a11y-states name value) (format #f "~a=~a~%" name (string-join (map symbol->string value) ";"))) (define (serialize-string name value) (format #f "~a=~a~%" name value)) (define (serialize-number name value) (format #f "~a=~a~%" name value)) (define (serialize-list-of-strings _ value) (string-join value "\n")) (define-configuration lightdm-gtk-greeter-configuration (lightdm-gtk-2019-11-18linux-boot: Don't ignore options when mounting root file system....Guillaume Le Vaillant 2019-11-18linux-boot: Fix indentation....Maxim Cournoyer theme to use.") (icon-theme-name (string "Adwaita") "The name of the icon theme to use.") (cursor-theme-name (string "Adwaita") "The name of the cursor theme to use.") (cursor-theme-size (number 16) "The size to use for the cursor theme.") (allow-debugging? maybe-boolean "Set to #t to enable debug log level.") (background (file-like (file-append %artwork-repository "/backgrounds/guix-checkered-16-9.svg")) "The background image to use.") ;; FIXME: This should be enabled by default, but it currently doesn't work, ;; failing to connect to D-Bus, causing the login to fail. (at-spi-enabled? (boolean #f) "Enable accessibility support through the Assistive Technology Service Provider Interface (AT-SPI).") (a11y-states (list-of-a11y-states %a11y-states) "The accessibility features to enable, given as list of symbols.") (reader maybe-file-like "The command to use to launch a screen reader.") (extra-config (list-of-strings '()) "Extra configuration values to append to the LightDM GTK Greeter configuration file.")) (define (strip-record-type-name-brackets name) "Remove the '<' and '>' brackets from NAME, a symbol." (let ((name (symbol->string name))) (if (and (string-prefix? "<" name) (string-suffix? ">" name)) (string->symbol (string-drop (string-drop-right name 1) 1)) (error "unexpected record type name" name)))) (define (config->name config) "Return the constructor name (a symbol) from CONFIG." (strip-record-type-name-brackets (record-type-name (struct-vtable config)))) (define (greeter-configuration->greeter-fields config) "Return the fields of CONFIG, a greeter configuration." (match config ;; Note: register any new greeter configuration here. ((? lightdm-gtk-greeter-configuration?) lightdm-gtk-greeter-configuration-fields))) (define (greeter-configuration->packages config) "Return the list of greeter packages, including assets, used by CONFIG, a greeter configuration." (match config ;; Note: register any new greeter configuration here. ((? lightdm-gtk-greeter-configuration?) (cons (lightdm-gtk-greeter-configuration-lightdm-gtk-greeter config) (lightdm-gtk-greeter-configuration-assets config))))) ;;; TODO: Implement directly in (gnu services configuration), perhaps by ;;; making the FIELDS argument optional. (define (serialize-configuration* config) "Like `serialize-configuration', but not requiring to provide a FIELDS argument." (define fields (greeter-configuration->greeter-fields config)) (serialize-configuration config fields)) (define (greeter-configuration->conf-name config) "Return the file name of CONFIG, a greeter configuration." (format #f "~a.conf" (greeter-configuration->greeter-session config))) (define (greeter-configuration->file config) "Serialize CONFIG into a file under the output directory, so that it can be easily added to XDG_CONF_DIRS." (computed-file (greeter-configuration->conf-name config) #~(begin (call-with-output-file #$output (lambda (port) (format port (string-append "[greeter]\n" #$(serialize-configuration* config)))))))) ;;; ;;; Seats. ;;; (define seat-name? string?) (define (serialize-seat-name _ value) (format #f "[Seat:~a]~%" value)) (define (seat-type? type) (memq type '(local xremote))) (define (serialize-seat-type name value) (format #f "~a=~a~%" name value)) (define-maybe seat-type) (define (greeter-session? value) (memq value '(lightdm-gtk-greeter))) (define (serialize-greeter-session name value) (format #f "~a=~a~%" name value)) (define-maybe greeter-session) (define-maybe string) ;;; Note: all the fields except for the seat name should be 'maybe's, since ;;; the real default value is set by the %lightdm-seat-default define later, ;;; and this avoids repeating ourselves in the serialized configuration file. (define-configuration lightdm-seat-configuration (name seat-name "The name of the seat. An asterisk (*) can be used in the name to apply the seat configuration to all the seat names it matches.") (user-session maybe-string "The session to use by default. The session name must be provided as a lowercase string, such as @code{\"gnome\"}, @code{\"ratpoison\"}, etc.") (type (seat-type 'local) "The type of the seat, either the @code{local} or @code{xremote} symbol.") (autologin-user maybe-string "The username to automatically log in with by default.") (greeter-session (greeter-session 'lightdm-gtk-greeter) "The greeter session to use, specified as a symbol. Currently, only @code{lightdm-gtk-greeter} is supported.") ;; Note: xserver-command must be lazily computed, so that it can be ;; overridden via 'lightdm-configuration-xorg-configuration'. (xserver-command maybe-file-like "The Xorg server command to run.") (session-wrapper (file-like (xinitrc)) "The xinitrc session wrapper to use.") (extra-config (list-of-strings '()) "Extra configuration values to append to the seat configuration section.")) (define (greeter-session->greater-configuration-pred identifier) "Return the predicate to check if a configuration is of the type specifying a greeter identified by IDENTIFIER." (match identifier ;; Note: register any new greeter identifier here. ('lightdm-gtk-greeter lightdm-gtk-greeter-configuration?))) (define (greeter-configuration->greeter-session config) "Given CONFIG, a greeter configuration object, return its identifier, a symbol." (let ((suffix "-configuration") (greeter-conf-name (config->name config))) (string->symbol (string-drop-right (symbol->string greeter-conf-name) (string-length suffix))))) (define list-of-seat-configurations? (list-of lightdm-seat-configuration?)) ;;; ;;; LightDM. ;;; (define (greeter-configuration? config) (or (lightdm-gtk-greeter-configuration? config) ;; Note: register any new greeter configuration here. )) (define (list-of-greeter-configurations? greeter-configs) (and ((list-of greeter-configuration?) greeter-configs) ;; Greeter configurations must also not be provided more than once. (let* ((types (map (compose record-type-name struct-vtable) greeter-configs)) (dupes (filter (lambda (type) (< 1 (count (cut eq? type <>) types))) types))) (unless (null? dupes) (leave (G_ "duplicate greeter configurations: ~a~%") dupes))))) (define-configuration/no-serialization lightdm-configuration (lightdm (file-like lightdm) "The lightdm package to use.") (allow-empty-passwords? (boolean #f) "Whether users not having a password set can login.") (debug? (boolean #f) "Enable verbose output.") (xorg-configuration (xorg-configuration (xorg-configuration)) "The default Xorg server configuration to use to generate the Xorg server start script. It can be refined per seat via the @code{xserver-command} of the @code{} record, if desired.") (greeters (list-of-greeter-configurations (list (lightdm-gtk-greeter-configuration))) "The LightDM greeter configurations specifying the greeters to use.") (seats (list-of-seat-configurations (list (lightdm-seat-configuration (name "*")))) "The seat configurations to use. A LightDM seat is akin to a user.") (xdmcp? (boolean #f) "Whether a XDMCP server should listen on port UDP 177.") (xdmcp-listen-address maybe-string "The host or IP address the XDMCP server listens for incoming connections. When unspecified, listen on for any hosts/IP addresses.") (vnc-server? (boolean #f) "Whether a VNC server is started.") (vnc-server-command (file-like (file-append tigervnc-server "bin/Xvnc")) "The Xvnc command to use for the VNC server, it's possible to provide extra options not otherwise exposed along the command, for example to disable security: @lisp (vnc-server-command (file-append tigervnc-server \"/bin/Xvnc\" \" -SecurityTypes None\" )) @end lisp Or to set a PasswordFile for the classic (unsecure) VncAuth mechanism: @lisp (vnc-server-command (file-append tigervnc-server \"/bin/Xvnc\" \" -PasswordFile /var/lib/lightdm/.vnc/passwd\")) @end lisp The password file should be manually created using the @command{vncpasswd} command. Note that LightDM will create new sessions for VNC users, which means they need to authenticate in the same way as local users would. ") (vnc-server-listen-address maybe-string "The host or IP address the VNC server listens for incoming connections. When unspecified, listen for any hosts/IP addresses.") (vnc-server-port (number 5900) "The TCP port the VNC server should listen to.") (extra-config (list-of-strings '()) "Extra configuration values to append to the LightDM configuration file.")) (define (lightdm-configuration->greeters-config-dir config) "Return a directory containing all the serialized greeter configurations from CONFIG, a object." (file-union "etc-lightdm" (append-map (lambda (g) `((,(greeter-configuration->conf-name g) ,(greeter-configuration->file g)))) (lightdm-configuration-greeters config)))) (define (lightdm-configuration->packages config) "Return all the greeter packages and their assets defined in CONFIG, a object, as well as the lightdm package itself." (cons (lightdm-configuration-lightdm config) (append-map greeter-configuration->packages (lightdm-configuration-greeters config)))) (define (validate-lightdm-configuration config) "Sanity check CONFIG, a record instance." ;; This is required to make inter-field validations, such as between the ;; seats and greeters. (let* ((seats (lightdm-configuration-seats config)) (greeter-sessions (delete-duplicates (map lightdm-seat-configuration-greeter-session seats) eq?)) (greeter-configurations (lightdm-configuration-greeters config)) (missing-greeters (filter-map (lambda (id) (define pred (greeter-session->greater-configuration-pred id)) (if (find pred greeter-configurations) #f ;happy path id)) greeter-sessions))) (unless (null? missing-greeters) (leave (G_ "no greeter configured for seat greeter sessions: ~a~%") missing-greeters)))) (define (lightdm-configuration-file config) (match-record config (xorg-configuration seats xdmcp? xdmcp-listen-address vnc-server? vnc-server-command vnc-server-listen-address vnc-server-port extra-config) (apply mixed-text-file "lightdm.conf" " # # General configuration # [LightDM] greeter-user=lightdm sessions-directory=/run/current-system/profile/share/xsessions\ :/run/current-system/profile/share/wayland-sessions remote-sessions-directory=/run/current-system/profile/share/remote-sessions " #~(string-join '#$extra-config "\n") " # # XDMCP Server configuration # [XDMCPServer] enabled=" (if xdmcp? "true" "false") "\n" (if (maybe-value-set? xdmcp-listen-address) (format #f "xdmcp-listen-address=~a" xdmcp-listen-address) "") " # # VNC Server configuration # [VNCServer] enabled=" (if vnc-server? "true" "false") " command=" vnc-server-command " port=" (number->string vnc-server-port) "\n" (if (maybe-value-set? vnc-server-listen-address) (format #f "vnc-server-listen-address=~a" vnc-server-listen-address) "") " # # Seat configuration. # " (map (lambda (seat) ;; This complication exists to propagate a default value for ;; the 'xserver-command' field of the seats. Having a ;; 'xorg-configuration' field at the root of the ;; lightdm-configuration enables the use of ;; 'set-xorg-configuration' and can be more convenient. (let ((seat* (if (maybe-value-set? (lightdm-seat-configuration-xserver-command seat)) seat (lightdm-seat-configuration (inherit seat) (xserver-command (xorg-start-command xorg-configuration)))))) (serialize-configuration seat* lightdm-seat-configuration-fields))) seats)))) (define %lightdm-accounts (list (user-group (name "lightdm") (system? #t)) (user-account (name "lightdm") (group "lightdm") (system? #t) (comment "LightDM user") (home-directory "/var/lib/lightdm") (shell (file-append shadow "/sbin/nologin"))))) (define %lightdm-activation ;; Ensure /var/lib/lightdm is owned by the "lightdm" user. Adapted from the ;; %gdm-activation. (with-imported-modules '((guix build utils)) #~(begin (use-modules (guix build utils)) (define (ensure-ownership directory) (let* ((lightdm (getpwnam "lightdm")) (uid (passwd:uid lightdm)) (gid (passwd:gid lightdm)) (st (stat directory #f))) ;; Recurse into directory only if it has wrong ownership. (when (and st (or (not (= uid (stat:uid st))) (not (= gid (stat:gid st))))) (for-each (lambda (file) (chown file uid gid)) (find-files "directory" #:directories? #t))))) (when (not (stat "/var/lib/lightdm-data" #f)) (mkdir-p "/var/lib/lightdm-data")) (for-each ensure-ownership '("/var/lib/lightdm" "/var/lib/lightdm-data"))))) (define (lightdm-pam-service config) "Return a PAM service for @command{lightdm}." (unix-pam-service "lightdm" #:login-uid? #t #:allow-empty-passwords? (lightdm-configuration-allow-empty-passwords? config))) (define (lightdm-greeter-pam-service) "Return a PAM service for @command{lightdm-greeter}." (pam-service (name "lightdm-greeter") (auth (list ;; Load environment from /etc/environment and ~/.pam_environment. (pam-entry (control "required") (module "pam_env.so")) ;; Always let the greeter start without authentication. (pam-entry (control "required") (module "pam_permit.so")))) ;; No action required for account management (account (list (pam-entry (control "required") (module "pam_permit.so")))) ;; Prohibit changing password. (password (list (pam-entry (control "required") (module "pam_deny.so")))) ;; Setup session. (session (list (pam-entry (control "required") (module "pam_unix.so")))))) (define (lightdm-autologin-pam-service) "Return a PAM service for @command{lightdm-autologin}}." (pam-service (name "lightdm-autologin") (auth (list ;; Block login if user is globally disabled. (pam-entry (control "required") (module "pam_nologin.so")) (pam-entry (control "required") (module "pam_succeed_if.so") (arguments (list "uid >= 1000"))) ;; Allow access without authentication. (pam-entry (control "required") (module "pam_permit.so")))) ;; Stop autologin if account requires action. (account (list (pam-entry (control "required") (module "pam_unix.so")))) ;; Prohibit changing password. (password (list (pam-entry (control "required") (module "pam_deny.so")))) ;; Setup session. (session (list (pam-entry (control "required") (module "pam_unix.so")))))) (define (lightdm-pam-services config) (list (lightdm-pam-service config) (lightdm-greeter-pam-service) (lightdm-autologin-pam-service))) (define (lightdm-shepherd-service config) "Return a for LightDM using CONFIG." (validate-lightdm-configuration config) (define lightdm-command #~(list #$(file-append (lightdm-configuration-lightdm config) "/sbin/lightdm") #$@(if (lightdm-configuration-debug? config) #~("--debug") #~()) "--config" #$(lightdm-configuration-file config))) (define lightdm-paths (let ((lightdm (lightdm-configuration-lightdm config))) #~(string-join '#$(map (lambda (dir) (file-append lightdm dir)) '("/bin" "/sbin" "/libexec")) ":"))) (define greeters-config-dir (lightdm-configuration->greeters-config-dir config)) (define data-dirs ;; LightDM itself needs to be in XDG_DATA_DIRS for the accountsservice ;; interface it provides to be picked up. The greeters must also be in ;; XDG_DATA_DIRS to be found. (let ((packages (lightdm-configuration->packages config))) #~(string-join '#$(map (cut file-append <> "/share") packages) ":"))) (list (shepherd-service (documentation "LightDM display manager") (requirement '(pam dbus-system user-processes host-name)) (provision '(lightdm display-manager xorg-server)) (respawn? #f) (start ;; Note: sadly, environment variables defined for 'lightdm' are ;; cleared and/or overridden by /etc/profile by its spawned greeters, ;; so an out-of-band means such as /etc is required. #~(make-forkexec-constructor #$lightdm-command ;; Lightdm needs itself in its PATH. #:environment-variables (list ;; It knows to look for greeter ;; configurations in XDG_CONFIG_DIRS... (string-append "XDG_CONFIG_DIRS=" #$greeters-config-dir) ;; ... and for greeter .desktop files as ;; well as lightdm accountsservice ;; interface in XDG_DATA_DIRS. (string-append "XDG_DATA_DIRS=" #$data-dirs) (string-append "PATH=" #$lightdm-paths)))) (stop #~(make-kill-destructor))))) (define lightdm-service-type (handle-xorg-configuration lightdm-configuration (service-type (name 'lightdm) (default-value (lightdm-configuration)) (extensions (list (service-extension pam-root-service-type lightdm-pam-services) (service-extension shepherd-root-service-type lightdm-shepherd-service) (service-extension activation-service-type (const %lightdm-activation)) (service-extension dbus-root-service-type (compose list lightdm-configuration-lightdm)) (service-extension polkit-service-type (compose list lightdm-configuration-lightdm)) (service-extension account-service-type (const %lightdm-accounts)) ;; Add 'lightdm' to the system profile, so that its ;; 'share/accountsservice' D-Bus service extension directory can be ;; found via the 'XDG_DATA_DIRS=/run/current-system/profile/share' ;; environment variable set in the wrapper of the ;; libexec/accounts-daemon binary of the accountsservice package. ;; This daemon is spawned by D-Bus, and there's little we can do to ;; affect its environment. For more reading, see: ;; https://github.com/NixOS/nixpkgs/issues/45059. (service-extension profile-service-type lightdm-configuration->packages) ;; This is needed for the greeter itself to find its configuration, ;; because XDG_CONF_DIRS gets overridden by /etc/profile. (service-extension etc-service-type (lambda (config) `(("lightdm" ,(lightdm-configuration->greeters-config-dir config))))))) (description "Run @code{lightdm}, the LightDM graphical login manager.")))) ;;; ;;; Generate documentation. ;;; (define (generate-doc) (configuration->documentation 'lightdm-configuration) (configuration->documentation 'lightdm-gtk-greeter-configuration) (configuration->documentation 'lightdm-seat-configuration))