services: greetd: Improve greeter configurations.

This improvement focuses on providing common user session scripts
for use by multiple greeters. Now user session entry point is
factored out into '<greetd-user-session>', which can be reused
as is with different greeters. By default it uses 'bash' as
first user process. Then user normally starts additional programs
with '.profile' or '.bashrc'. Using 'command', 'command-args' and
'extra-env' one can specify something else, which could be
'dbus-session' wrapped process, some desktop environment or else.
While the above is possible, one is still encouraged to use
'.bashrc', '.profile' or similar.

It also fixes incorrect use of 'XDG_RUNTIME_DIR' for 'wlgreet'.
'wlgreet' requires a compositor to run. We provide common sway based
greeter script, which can be shared by other graphical greeters.

* gnu/services/base.scm (<greetd-user-session>): Common user session
factored out, for shared use by multiple greeters.
(<greetd-agreety-session>): Switch to common user session.
(<greetd-wlgreet-configuration>): Refactor 'wlgreet' configuration.
(<greetd-wlgreet-sway-session>): Switch to common user session.
(<greetd-terminal-configuration>): Add 'extra-shepherd-requirement'
for establishing configurable Shepherd service dependency.
* gnu/tests/desktop.scm (%minimal-services): Reflect configuration
changes.
* doc/guix.texi (Base Services): Document refactoring changes.

Change-Id: I9d45a592b355eb9c438be5b1d4d15555ce4956fa
Modified-by: Maxim Cournoyer <maxim.cournoyer@gmail.com>
Signed-off-by: Maxim Cournoyer <maxim.cournoyer@gmail.com>

3 files changed, 379 insertions, 163 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index 4fcddb98cb..00d3dba316 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -20512,13 +20512,21 @@ Here is an example of switching from @code{mingetty-service-type} to
                  (terminal-vt "2")
                  (default-session-command
                    (greetd-agreety-session
-                    (extra-env '(("MY_VAR" . "1")))
-                    (xdg-env? #f))))
+                    (command
+                     (greetd-user-session
+                      (extra-env '(("MY_VAR" . "1")))
+                      (xdg-env? #f))))))
                 ;; we can use different shell instead of default bash
                 (greetd-terminal-configuration
                  (terminal-vt "3")
                  (default-session-command
-                   (greetd-agreety-session (command (file-append zsh "/bin/zsh")))))
+                   (greetd-agreety-session
+                    (command
+                     (greetd-user-session
+                      (command (file-append zsh "/bin/zsh"))
+                      (command-args '("-l"))
+                      (extra-env '(("MY_VAR" . "1")))
+                      (xdg-env? #f))))))
                 ;; we can use any other executable command as greeter
                 (greetd-terminal-configuration
                  (terminal-vt "4")
@@ -20563,6 +20571,12 @@ Configuration record for per terminal greetd daemon service.
 @item @code{greetd} (default: @code{greetd})
 The greetd package to use.
 
+@item @code{shepherd-requirement} (default: @code{'()})
+This option can be used to provide a list of additional symbols naming
+Shepherd services that this service will depend on, such as
+@code{'seatd} or @code{'elogind} when the terminal session is a
+graphical greeter.
+
 @item @code{config-file-name}
 Configuration file name to use for greetd daemon. Generally, autogenerated
 derivation based on @code{terminal-vt} value.
@@ -20586,21 +20600,24 @@ exist.
 The user to use for running the greeter.
 
 @item @code{default-session-command} (default: @code{(greetd-agreety-session)})
-Can be either instance of @code{greetd-agreety-session} configuration or
+Can be either @code{greetd-agreety-session}, @code{greetd-wlgreet-sway-session} or
 @code{gexp->script} like object to use as greeter.
 
 @end table
 @end deftp
 
-@deftp {Data Type} greetd-agreety-session
-Configuration record for the agreety greetd greeter.
+@deftp {Data Type} greetd-user-session
+Configuration record for the user session command.  Greeters require the
+user command to be specified in some or another way.
+@code{greetd-user-session} provides a common command for that.  Users
+should prefer POSIX shell commands like @command{bash}, which can start
+an actual user terminal shell, window manager or desktop environment
+with their own mechanism, for example via @file{~/.bashrc} in the case
+of Bash.
 
 @table @asis
-@item @code{agreety} (default: @code{greetd})
-The package with @command{/bin/agreety} command.
-
 @item @code{command} (default: @code{(file-append bash "/bin/bash")})
-Command to be started by @command{/bin/agreety} on successful login.
+Command to be started by @command{agreety} on successful login.
 
 @item @code{command-args} (default: @code{'("-l")})
 Command arguments to pass to command.
@@ -20608,27 +20625,37 @@ Command arguments to pass to command.
 @item @code{extra-env} (default: @code{'()})
 Extra environment variables to set on login.
 
+@item @code{xdg-session-type} (default: @code{"tty"})
+Specify the value of @code{XDG_SESSION_TYPE}.  The user environment may
+adapt depending on its value (normally by using @file{.bashrc} or
+similar).
+
 @item @code{xdg-env?} (default: @code{#t})
 If true @code{XDG_RUNTIME_DIR} and @code{XDG_SESSION_TYPE} will be set
-before starting command. One should note that, @code{extra-env} variables
+before starting command.  One should note that, @code{extra-env} variables
 are set right after mentioned variables, so that they can be overridden.
 
 @end table
 @end deftp
 
-@deftp {Data Type} greetd-wlgreet-session
-Generic configuration record for the wlgreet greetd greeter.
+@deftp {Data Type} greetd-agreety-session
+Configuration record for the agreety greetd greeter.
 
 @table @asis
-@item @code{wlgreet} (default: @code{wlgreet})
-The package with the @command{/bin/wlgreet} command.
+@item @code{agreety} (default: @code{greetd})
+The package providing the @command{agreety} command.
 
-@item @code{command} (default: @code{(file-append sway "/bin/sway")})
-Command to be started by @command{/bin/wlgreet} on successful login.
+@item @code{command} (default: @code{(greetd-user-session)})
+Command to be started by @command{agreety} on successful login, an
+instance of @code{greetd-user-session}.
 
-@item @code{command-args} (default: @code{'()})
-Command arguments to pass to command.
+@end table
+@end deftp
 
+@deftp {Data Type} greetd-wlgreet-configuration
+Generic configuration record for the wlgreet greetd greeter.
+
+@table @asis
 @item @code{output-mode} (default: @code{"all"})
 Option to use for @code{outputMode} in the TOML configuration file.
 
@@ -20650,9 +20677,6 @@ RGBA list to use as the error colour of the UI popup.
 @item @code{border} (default: @code{'(1 1 1 1)})
 RGBA list to use as the border colour of the UI popup.
 
-@item @code{extra-env} (default: @code{'()})
-Extra environment variables to set on login.
-
 @end table
 @end deftp
 
@@ -20665,28 +20689,41 @@ A @code{greetd-wlgreet-session} record for generic wlgreet configuration,
 on top of the Sway-specific @code{greetd-wlgreet-sway-session}.
 
 @item @code{sway} (default: @code{sway})
-The package providing the @command{/bin/sway} command.
+The package providing the @command{sway} command.
 
 @item @code{sway-configuration} (default: #f)
 File-like object providing an additional Sway configuration file to be
 prepended to the mandatory part of the configuration.
 
+@item @code{wlgreet} (default: @code{wlgreet})
+The package providing the @command{wlgreet} command.
+
+@item @code{wlgreet-configuration} (default: @code{(greetd-wlgreet-configuration)})
+Configuration of @code{wlgreet} represented
+by @code{greetd-wlgreet-configuration}.
+
+@item @code{command} (default: @code{(greetd-user-session)})
+Command to be started by @command{wlgreet} on successful login, an
+instance of @code{greetd-user-session}.
+
 @end table
 
 Here is an example of a greetd configuration that uses wlgreet and Sway:
 
 @lisp
   (greetd-configuration
-   ;; We need to give the greeter user these permissions, otherwise
-   ;; Sway will crash on launch.
+   ;; The graphical greeter requires additional group membership.
    (greeter-supplementary-groups (list "video" "input" "seat"))
    (terminals
     (list (greetd-terminal-configuration
+           ;; Sway requires seatd service.
+           (extra-shepherd-requirement '(seatd))
            (terminal-vt "1")
            (terminal-switch #t)
            (default-session-command
             (greetd-wlgreet-sway-session
              (sway-configuration
+              ;; Optional extra sway configuration.
               (local-file "sway-greetd.conf"))))))))
 @end lisp
 @end deftp
diff --git a/gnu/services/base.scm b/gnu/services/base.scm
index 7331c030d7..fce82094f6 100644
--- a/gnu/services/base.scm
+++ b/gnu/services/base.scm
@@ -16,7 +16,7 @@
 ;;; Copyright © 2021 qblade <qblade@protonmail.com>
 ;;; Copyright © 2021 Hui Lu <luhuins@163.com>
 ;;; Copyright © 2021, 2022, 2023 Maxim Cournoyer <maxim.cournoyer@gmail.com>
-;;; Copyright © 2021 muradm <mail@muradm.net>
+;;; Copyright © 2021, 2025 muradm <mail@muradm.net>
 ;;; Copyright © 2022 Guillaume Le Vaillant <glv@posteo.net>
 ;;; Copyright © 2022 Justin Veilleux <terramorpha@cock.li>
 ;;; Copyright © 2022 ( <paren@disroot.org>
@@ -274,8 +274,10 @@
             greetd-service-type
             greetd-configuration
             greetd-terminal-configuration
+            greetd-user-session
             greetd-agreety-session
-            greetd-wlgreet-session
+            greetd-wlgreet-session  ; deprecated
+            greetd-wlgreet-configuration
             greetd-wlgreet-sway-session
 
             %base-services))
@@ -3393,87 +3395,220 @@ to handle."
 ;;; greetd-service-type -- minimal and flexible login manager daemon
 ;;;
 
+(define-record-type* <greetd-user-session>
+  greetd-user-session make-greetd-user-session greetd-user-session?
+  (command greetd-user-session-command (default (file-append bash "/bin/bash")))
+  (command-args greetd-user-session-command-args (default '("-l")))
+  (extra-env greetd-user-session-extra-env (default '()))
+  (xdg-session-type greetd-user-session-xdg-session-type (default "tty"))
+  (xdg-env? greetd-user-session-xdg-env? (default #t)))
+
+(define (make-greetd-user-session-command config)
+  (match-record config <greetd-user-session>
+                (command command-args extra-env)
+                (program-file
+                 "greetd-user-session-command"
+                 #~(begin
+                     (use-modules (ice-9 match))
+                     (for-each (match-lambda ((var . val) (setenv var val)))
+                               (quote (#$@extra-env)))
+                     (apply execl #$command #$command
+                            (list #$@command-args))))))
+
+(define (make-greetd-xdg-user-session-command config)
+  (match-record config <greetd-user-session>
+                (command command-args extra-env xdg-session-type)
+                (program-file
+                 "greetd-xdg-user-session-command"
+                 #~(begin
+                     (use-modules (ice-9 match))
+                     (let* ((username (getenv "USER"))
+                            (useruid (passwd:uid (getpwuid username)))
+                            (useruid (number->string useruid)))
+                       (setenv "XDG_SESSION_TYPE" #$xdg-session-type)
+                       (setenv "XDG_RUNTIME_DIR"
+                               (string-append "/run/user/" useruid)))
+                     (for-each (match-lambda ((var . val) (setenv var val)))
+                               (quote (#$@extra-env)))
+                     (apply execl #$command #$command
+                            (list #$@command-args))))))
+
+(define-gexp-compiler (greetd-user-session-compiler
+                       (session <greetd-user-session>)
+                       system target)
+  (lower-object
+   ((if (greetd-user-session-xdg-env? session)
+        make-greetd-xdg-user-session-command
+        make-greetd-user-session-command) session)))
+
 (define-record-type* <greetd-agreety-session>
-  greetd-agreety-session make-greetd-agreety-session
-  greetd-agreety-session?
-  (agreety greetd-agreety (default greetd))
-  (command greetd-agreety-command (default (file-append bash "/bin/bash")))
-  (command-args greetd-agreety-command-args (default '("-l")))
-  (extra-env greetd-agreety-extra-env (default '()))
-  (xdg-env? greetd-agreety-xdg-env? (default #t)))
-
-(define (greetd-agreety-tty-session-command config)
-  (match-record config <greetd-agreety-session>
-    (command command-args extra-env)
-    (program-file
-     "agreety-tty-session-command"
-     #~(begin
-         (use-modules (ice-9 match))
-         (for-each (match-lambda ((var . val) (setenv var val)))
-                   (quote (#$@extra-env)))
-         (apply execl #$command #$command (list #$@command-args))))))
-
-(define (greetd-agreety-tty-xdg-session-command config)
-  (match-record config <greetd-agreety-session>
-    (command command-args extra-env)
-    (program-file
-     "agreety-tty-xdg-session-command"
-     #~(begin
-         (use-modules (ice-9 match))
-         (let*
-             ((username (getenv "USER"))
-              (useruid (passwd:uid (getpwuid username)))
-              (useruid (number->string useruid)))
-           (setenv "XDG_SESSION_TYPE" "tty")
-           (setenv "XDG_RUNTIME_DIR" (string-append "/run/user/" useruid)))
-         (for-each (match-lambda ((var . val) (setenv var val)))
-                   (quote (#$@extra-env)))
-         (apply execl #$command #$command (list #$@command-args))))))
+  greetd-agreety-session make-greetd-agreety-session greetd-agreety-session?
+  (agreety greetd-agreety-session-agreety (default greetd))
+  (command greetd-agreety-session-command
+           (default (greetd-user-session))
+           (sanitize warn-greetd-agreety-session-command-type))
+  (command-args greetd-agreety-command-args
+                (default #nil)
+                (sanitize warn-deprecated-greetd-agreety-command-args))
+  (extra-env greetd-agreety-extra-env
+             (default #nil)
+             (sanitize warn-deprecated-greetd-agreety-extra-env))
+  (xdg-env? greetd-agreety-xdg-env?
+            (default #nil)
+            (sanitize warn-deprecated-greetd-agreety-xdg-env?)))
+
+(define (warn-deprecated-greetd-agreety-command-args value)
+  (unless (nil? value)
+    (warn-about-deprecation
+     'command-args #f
+     #:replacement '<greetd-user-seesion>))
+  value)
+
+(define (warn-deprecated-greetd-agreety-extra-env value)
+  (unless (nil? value)
+    (warn-about-deprecation
+     'extra-env #f
+     #:replacement '<greetd-user-seesion>))
+  value)
+
+(define (warn-deprecated-greetd-agreety-xdg-env? value)
+  (unless (nil? value)
+    (warn-about-deprecation
+     'xdg-env? #f
+     #:replacement '<greetd-user-seesion>))
+  value)
+
+(define-deprecated/alias greetd-agreety greetd-agreety-session-agreety)
+(define-deprecated/alias greetd-agreety-command greetd-agreety-session-command)
+
+(define (warn-greetd-agreety-session-command-type value)
+  (unless (greetd-user-session? value)
+    (warn-about-deprecation
+     "arbitrary command" #f
+     #:replacement '<greetd-user-session>))
+  value)
+
+(define (greetd-agreety-session-to-user-session session default-command)
+  (let ((command (greetd-agreety-session-command session))
+        (command-args (or (greetd-agreety-command-args session)
+                          (greetd-user-session-command-args default-command)))
+        (extra-env (or (greetd-agreety-extra-env session)
+                       (greetd-user-session-extra-env default-command)))
+        (xdg-env? (or (greetd-agreety-xdg-env? session)
+                      (greetd-user-session-xdg-env? default-command))))
+    (greetd-user-session
+     (command command)
+     (command-args command-args)
+     (extra-env extra-env)
+     (xdg-env? xdg-env?))))
 
 (define-gexp-compiler (greetd-agreety-session-compiler
                        (session <greetd-agreety-session>)
                        system target)
-  (let ((agreety (file-append (greetd-agreety session)
-                              "/bin/agreety"))
-        (command ((if (greetd-agreety-xdg-env? session)
-                      greetd-agreety-tty-xdg-session-command
-                      greetd-agreety-tty-session-command)
-                  session)))
+  (let* ((agreety
+          (file-append (greetd-agreety-session-agreety session) "/bin/agreety"))
+         (command
+          (greetd-agreety-session-command session))
+         (command
+          (if (greetd-user-session? command)
+              command
+              (greetd-agreety-session-to-user-session
+               session
+               (greetd-user-session)))))
     (lower-object
-     (program-file "agreety-command"
-       #~(execl #$agreety #$agreety "-c" #$command)))))
+     (program-file
+      "agreety-wrapper"
+      #~(execl #$agreety #$agreety "-c" #$command)))))
 
-(define-record-type* <greetd-wlgreet-session>
-  greetd-wlgreet-session make-greetd-wlgreet-session
-  greetd-wlgreet-session?
-  (wlgreet greetd-wlgreet (default wlgreet))
+(define (make-greetd-sway-greeter-command sway sway-config)
+  (let ((sway-bin (file-append sway "/bin/sway")))
+    (program-file
+     "greeter-sway-command"
+     (with-imported-modules '((guix build utils))
+       #~(begin
+           (use-modules (guix build utils))
+
+           (let* ((username (getenv "USER"))
+                  (user (getpwnam username))
+                  (useruid (passwd:uid user))
+                  (usergid (passwd:gid user))
+                  (useruid-s (number->string useruid))
+                  ;; /run/user/<greeter-user-uid> won't exist yet
+                  ;; this will contain WAYLAND_DISPLAY socket file
+                  ;; and log-file below
+                  (user-home-dir "/tmp/.greeter-home")
+                  (user-xdg-runtime-dir (string-append user-home-dir "/run"))
+                  (user-xdg-cache-dir (string-append user-home-dir "/cache"))
+                  (log-file (string-append (number->string (getpid)) ".log"))
+                  (log-file (string-append user-home-dir "/" log-file)))
+             (for-each (lambda (d)
+                         (mkdir-p d)
+                         (chown d useruid usergid) (chmod d #o700))
+                       (list user-home-dir
+                             user-xdg-runtime-dir
+                             user-xdg-cache-dir))
+             (setenv "HOME" user-home-dir)
+             (setenv "XDG_CACHE_DIR" user-xdg-cache-dir)
+             (setenv "XDG_RUNTIME_DIR" user-xdg-runtime-dir)
+             (dup2 (open-fdes log-file
+                              (logior O_CREAT O_WRONLY O_APPEND) #o640) 1)
+             (dup2 1 2)
+             (execl #$sway-bin #$sway-bin "-d" "-c" #$sway-config)))))))
+
+(define-record-type* <greetd-wlgreet-configuration>
+  greetd-wlgreet-configuration make-greetd-wlgreet-configuration
+  greetd-wlgreet-configuration?
+  (output-mode greetd-wlgreet-configuration-output-mode (default "all"))
+  (scale greetd-wlgreet-configuration-scale (default 1))
+  (background greetd-wlgreet-configuration-background (default '(0 0 0 0.9)))
+  (headline greetd-wlgreet-configuration-headline (default '(1 1 1 1)))
+  (prompt greetd-wlgreet-configuration-prompt (default '(1 1 1 1)))
+  (prompt-error greetd-wlgreet-configuration-prompt-error (default '(1 1 1 1)))
+  (border greetd-wlgreet-configuration-border (default '(1 1 1 1)))
+  (wlgreet greetd-wlgreet
+           (default #nil)
+           (sanitize warn-deprecated-greetd-wlgreet))
   (command greetd-wlgreet-command
-           (default (file-append sway "/bin/sway")))
-  (command-args greetd-wlgreet-command-args (default '()))
-  (output-mode greetd-wlgreet-output-mode (default "all"))
-  (scale greetd-wlgreet-scale (default 1))
-  (background greetd-wlgreet-background (default '(0 0 0 0.9)))
-  (headline greetd-wlgreet-headline (default '(1 1 1 1)))
-  (prompt greetd-wlgreet-prompt (default '(1 1 1 1)))
-  (prompt-error greetd-wlgreet-prompt-error (default '(1 1 1 1)))
-  (border greetd-wlgreet-border (default '(1 1 1 1)))
-  (extra-env greetd-wlgreet-extra-env (default '())))
-
-(define (greetd-wlgreet-wayland-session-command session)
-  (program-file "wlgreet-session-command"
-    #~(let* ((username (getenv "USER"))
-             (useruid (number->string
-                       (passwd:uid (getpwuid username))))
-             (command #$(greetd-wlgreet-command session)))
-        (use-modules (ice-9 match))
-        (setenv "XDG_SESSION_TYPE" "wayland")
-        (setenv "XDG_RUNTIME_DIR" (string-append "/run/user/" useruid))
-        (for-each (lambda (env) (setenv (car env) (cdr env)))
-                  '(#$@(greetd-wlgreet-extra-env session)))
-        (apply execl command command
-               (list #$@(greetd-wlgreet-command-args session))))))
-
-(define (make-wlgreet-config-color section-name color)
+           (default #nil)
+           (sanitize warn-deprecated-greetd-wlgreet-command))
+  (command-args greetd-wlgreet-command-args
+                (default #nil)
+                (sanitize warn-deprecated-greetd-wlgreet-command-args))
+  (extra-env greetd-wlgreet-extra-env
+             (default #nil)
+             (sanitize warn-deprecated-greetd-wlgreet-extra-env)))
+
+(define-deprecated/alias greetd-wlgreet-session greetd-wlgreet-configuration)
+
+(define (warn-deprecated-greetd-wlgreet value)
+  (unless (nil? value)
+    (warn-about-deprecation
+     'wlgreet #f
+     #:replacement '<greetd-wlgreet-sway-session>))
+  value)
+
+(define (warn-deprecated-greetd-wlgreet-command value)
+  (unless (nil? value)
+    (warn-about-deprecation
+     'command #f
+     #:replacement '<greetd-wlgreet-sway-session>))
+  value)
+
+(define (warn-deprecated-greetd-wlgreet-command-args value)
+  (unless (nil? value)
+    (warn-about-deprecation
+     'command-args #f
+     #:replacement '<greetd-wlgreet-sway-session>))
+  value)
+
+(define (warn-deprecated-greetd-wlgreet-extra-env value)
+  (unless (nil? value)
+    (warn-about-deprecation
+     'extra-env #f
+     #:replacement '<greetd-wlgreet-sway-session>))
+  value)
+
+(define (make-greetd-wlgreet-config-color section-name color)
   (match color
     ((red green blue opacity)
      (string-append
@@ -3483,76 +3618,103 @@ to handle."
       "blue = " (number->string blue) "\n"
       "opacity = " (number->string opacity) "\n"))))
 
-(define (make-wlgreet-configuration-file session)
-  (let ((command (greetd-wlgreet-wayland-session-command session))
-        (output-mode (greetd-wlgreet-output-mode session))
-        (scale (greetd-wlgreet-scale session))
-        (background (greetd-wlgreet-background session))
-        (headline (greetd-wlgreet-headline session))
-        (prompt (greetd-wlgreet-prompt session))
-        (prompt-error (greetd-wlgreet-prompt-error session))
-        (border (greetd-wlgreet-border session)))
-    (mixed-text-file "wlgreet.toml"
-      "command = \"" command "\"\n"
-      "outputMode = \"" output-mode "\"\n"
-      "scale = " (number->string scale) "\n"
-      (apply string-append
-             (map (match-lambda
-                    ((section-name . color)
-                     (make-wlgreet-config-color section-name color)))
-                  `(("background" . ,background)
-                    ("headline" . ,headline)
-                    ("prompt" . ,prompt)
-                    ("prompt-error" . ,prompt-error)
-                    ("border" . ,border)))))))
+(define (make-greetd-wlgreet-config command color)
+  (match-record color <greetd-wlgreet-configuration>
+    (output-mode scale background headline prompt prompt-error border)
+    (mixed-text-file
+     "wlgreet.toml"
+     "command = \"" command "\"\n"
+     "outputMode = \"" output-mode "\"\n"
+     "scale = " (number->string scale) "\n"
+     (apply string-append
+            (map (match-lambda
+                   ((section-name . color)
+                    (make-greetd-wlgreet-config-color section-name color)))
+                 `(("background" . ,background)
+                   ("headline" . ,headline)
+                   ("prompt" . ,prompt)
+                   ("prompt-error" . ,prompt-error)
+                   ("border" . ,border)))))))
 
 (define-record-type* <greetd-wlgreet-sway-session>
   greetd-wlgreet-sway-session make-greetd-wlgreet-sway-session
   greetd-wlgreet-sway-session?
-  (wlgreet-session greetd-wlgreet-sway-session-wlgreet-session       ;<greetd-wlgreet-session>
-                   (default (greetd-wlgreet-session)))
-  (sway greetd-wlgreet-sway-session-sway (default sway))             ;<package>
-  (sway-configuration greetd-wlgreet-sway-session-sway-configuration ;file-like
-                      (default (plain-file "wlgreet-sway-config" ""))))
-
-(define (make-wlgreet-sway-configuration-file session)
-  (let* ((wlgreet-session (greetd-wlgreet-sway-session-wlgreet-session session))
-         (wlgreet-config (make-wlgreet-configuration-file wlgreet-session))
-         (wlgreet (file-append (greetd-wlgreet wlgreet-session) "/bin/wlgreet"))
-         (sway-config (greetd-wlgreet-sway-session-sway-configuration session))
-         (swaymsg (file-append (greetd-wlgreet-sway-session-sway session)
-                               "/bin/swaymsg")))
-    (mixed-text-file "wlgreet-sway.conf"
-      "include " sway-config "\n"
-      "xwayland disable\n"
-      "exec \"" wlgreet " --config " wlgreet-config "; "
-      swaymsg " exit\"\n")))
+  (sway greetd-wlgreet-sway-session-sway (default sway))
+  (sway-configuration greetd-wlgreet-sway-session-sway-configuration
+                      (default #f))
+  (wlgreet greetd-wlgreet-sway-session-wlgreet (default wlgreet))
+  (wlgreet-configuration greetd-wlgreet-sway-session-wlgreet-configuration
+                         (default (greetd-wlgreet-configuration)))
+  (command greetd-wlgreet-sway-session-command (default (greetd-user-session)))
+  (wlgreet-session
+   greetd-wlgreet-sway-session-wlgreet-session
+   (default #nil)
+   (sanitize warn-deprecated-greetd-wlgreet-sway-session-wlgreet-session)))
+
+(define (warn-deprecated-greetd-wlgreet-sway-session-wlgreet-session value)
+  (unless (nil? value)
+    (warn-about-deprecation
+     'wlgreet-session #f
+     #:replacement 'wlgreet-configuration))
+  value)
+
+(define (make-greetd-wlgreet-sway-session-sway-config session)
+  (match-record session <greetd-wlgreet-sway-session>
+                (sway sway-configuration wlgreet wlgreet-configuration command)
+    (let ((wlgreet-bin (file-append wlgreet "/bin/wlgreet"))
+          (wlgreet-config-file
+           (make-greetd-wlgreet-config command wlgreet-configuration))
+          (swaymsg-bin (file-append sway "/bin/swaymsg")))
+      (mixed-text-file
+       "wlgreet-sway-config"
+       (if sway-configuration
+           #~(string-append "include " #$sway-configuration "\n")
+           "")
+       "xwayland disable\n"
+       "exec \"" wlgreet-bin " --config " wlgreet-config-file
+       "; " swaymsg-bin " exit\"\n"))))
+
+(define (greetd-wlgreet-session-to-config session config)
+  (let* ((wlgreet (or (greetd-wlgreet config)
+                      (greetd-wlgreet-sway-session-wlgreet session)))
+         (default-command (greetd-wlgreet-sway-session-command session))
+         (command (or (greetd-wlgreet-command config)
+                      (greetd-user-session-command default-command)))
+         (command-args (or (greetd-wlgreet-command-args config)
+                           (greetd-user-session-command-args default-command)))
+         (extra-env (or (greetd-wlgreet-extra-env config)
+                        (greetd-user-session-extra-env default-command))))
+    (greetd-wlgreet-sway-session
+     (sway (greetd-wlgreet-sway-session-sway session))
+     (sway-configuration
+      (greetd-wlgreet-sway-session-sway-configuration session))
+     (wlgreet wlgreet)
+     (wlgreet-configuration config)
+     (command
+      (greetd-user-session
+       (command command)
+       (command-args command-args)
+       (extra-env extra-env))))))
 
 (define-gexp-compiler (greetd-wlgreet-sway-session-compiler
                        (session <greetd-wlgreet-sway-session>)
                        system target)
-  (let ((sway (file-append (greetd-wlgreet-sway-session-sway session)
-                           "/bin/sway"))
-        (config (make-wlgreet-sway-configuration-file session)))
-    (lower-object
-     (program-file "wlgreet-sway-session-command"
-       #~(let* ((log-file (open-output-file
-                           (string-append "/tmp/sway-greeter."
-                                          (number->string (getpid))
-                                          ".log")))
-                (username (getenv "USER"))
-                (useruid (number->string (passwd:uid (getpwuid username)))))
-           ;; redirect stdout/err to log-file
-           (dup2 (fileno log-file) 1)
-           (dup2 1 2)
-           (sleep 1) ;give seatd/logind some time to start up
-           (setenv "XDG_RUNTIME_DIR" (string-append "/run/user/" useruid))
-           (execl #$sway #$sway "-d" "-c" #$config))))))
+  (let ((s (if (nil? (greetd-wlgreet-sway-session-wlgreet-session session))
+               session
+               (greetd-wlgreet-session-to-config
+                session
+                (greetd-wlgreet-sway-session-wlgreet-session session)))))
+    (match-record s <greetd-wlgreet-sway-session> (sway)
+      (lower-object
+       (make-greetd-sway-greeter-command
+        sway
+        (make-greetd-wlgreet-sway-session-sway-config s))))))
 
 (define-record-type* <greetd-terminal-configuration>
   greetd-terminal-configuration make-greetd-terminal-configuration
   greetd-terminal-configuration?
   (greetd greetd-package (default greetd))
+  (shepherd-requirement greetd-shepherd-requirement (default '()))
   (config-file-name greetd-config-file-name (thunked)
                     (default (default-config-file-name this-record)))
   (log-file-name greetd-log-file-name (thunked)
@@ -3625,7 +3787,8 @@ to handle."
          (name "greeter")
          (group "greeter")
          (supplementary-groups (greetd-greeter-supplementary-groups config))
-         (system? #t))))
+         (system? #t)
+         (create-home-directory? #f))))
 
 (define (make-greetd-pam-mount-conf-file config)
   (computed-file
@@ -3675,6 +3838,11 @@ to handle."
                              (list optional-pam-mount))))
            pam))))))
 
+(define (greetd-run-user-activation config)
+  #~(let ((d "/run/user"))
+      (mkdir d #o755)
+      (chmod d #o755)))
+
 (define (greetd-shepherd-services config)
   (map
    (lambda (tc)
@@ -3682,10 +3850,12 @@ to handle."
          ((greetd-bin (file-append (greetd-package tc) "/sbin/greetd"))
           (greetd-conf (make-greetd-terminal-configuration-file tc))
           (greetd-log (greetd-log-file-name tc))
-          (greetd-vt (greetd-terminal-vt tc)))
+          (greetd-vt (greetd-terminal-vt tc))
+          (greetd-requirement (greetd-shepherd-requirement tc)))
        (shepherd-service
         (documentation "Minimal and flexible login manager daemon")
-        (requirement '(pam user-processes host-name udev virtual-terminal))
+        (requirement `(pam user-processes host-name udev virtual-terminal
+                           ,@greetd-requirement))
         (provision (list (symbol-append
                           'term-tty
                           (string->symbol (greetd-terminal-vt tc)))))
@@ -3706,6 +3876,7 @@ login manager daemon.")
     (list
      (service-extension account-service-type greetd-accounts)
      (service-extension file-system-service-type (const %greetd-file-systems))
+     (service-extension activation-service-type greetd-run-user-activation)
      (service-extension etc-service-type greetd-etc-service)
      (service-extension pam-root-service-type greetd-pam-service)
      (service-extension shepherd-root-service-type greetd-shepherd-services)))
diff --git a/gnu/tests/desktop.scm b/gnu/tests/desktop.scm
index 1c32076ccb..3f861b253b 100644
--- a/gnu/tests/desktop.scm
+++ b/gnu/tests/desktop.scm
@@ -141,13 +141,21 @@
                  (terminal-vt "2")
                  (default-session-command
                    (greetd-agreety-session
-                    (extra-env '(("MY_VAR" . "1")))
-                    (xdg-env? #f))))
+                    (command
+                     (greetd-user-session
+                      (extra-env '(("MY_VAR" . "1")))
+                      (xdg-env? #f))))))
                 ;; we can use different shell instead of default bash
                 (greetd-terminal-configuration
                  (terminal-vt "3")
                  (default-session-command
-                   (greetd-agreety-session (command (file-append zsh "/bin/zsh")))))
+                   (greetd-agreety-session
+                    (command
+                     (greetd-user-session
+                      (command (file-append zsh "/bin/zsh"))
+                      (command-args '("-l"))
+                      (extra-env '(("MY_VAR" . "1")))
+                      (xdg-env? #f))))))
                 ;; we can use any other executable command as greeter
                 (greetd-terminal-configuration
                  (terminal-vt "4")