[bug#56690] [PATCH] gnu: seatd-service-type: Should use seat group.

[muradm <mail@muradm.net>]

* gnu/services/desktop.scm (seatd-service-type): Uses "seat" group.
[extensions]: Added account-service-type with %seatd-accounts.
(%seatd-accounts): List with "seat" group.
(<seatd-configuration>): [group] Change default value to "seat".
* doc/guix.texi: Mention that users may need to become members of
"seat" group and update default value for group field.
---
 doc/guix.texi            | 18 +++++++++++++++++-
 gnu/services/desktop.scm |  8 ++++++--
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index 3c5864ec1a..750ed9b121 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -23151,6 +23151,22 @@ input), without requiring the applications needing access to be root.
   %base-services)
 
 @end lisp
+
+Users which are going to interact with @code{seatd} daemon while logged in
+should be added to @code{seat} group. For instance:
+
+@lisp
+(user-account
+  (name "alice")
+  (group "users")
+  (supplementary-groups '("wheel"   ;allow use of sudo, etc.
+                          "seat"    ;interact with seatd
+                          "audio"   ;sound card
+                          "video"   ;video devices such as webcams
+                          "cdrom")) ;the good ol' CD-ROM
+  (comment "Bob's sister"))
+@end lisp
+
 @end defvr
 
 @deftp {Data Type} seatd-configuration
@@ -23163,7 +23179,7 @@ The seatd package to use.
 @item @code{user} (default: @samp{"root"})
 User to own the seatd socket.
 
-@item @code{group} (default: @samp{"users"})
+@item @code{group} (default: @samp{"seat"})
 Group to own the seatd socket.
 
 @item @code{socket} (default: @samp{"/run/seatd.sock"})
diff --git a/gnu/services/desktop.scm b/gnu/services/desktop.scm
index 29a3722f1b..0d7cd71732 100644
--- a/gnu/services/desktop.scm
+++ b/gnu/services/desktop.scm
@@ -13,7 +13,7 @@
 ;;; Copyright © 2020 Tobias Geerinckx-Rice <me@tobias.gr>
 ;;; Copyright © 2020 Reza Alizadeh Majd <r.majd@pantherx.org>
 ;;; Copyright © 2021 Brice Waegeneire <brice@waegenei.re>
-;;; Copyright © 2021 muradm <mail@muradm.net>
+;;; Copyright © 2021, 2022 muradm <mail@muradm.net>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -1646,7 +1646,7 @@ (define-record-type* <seatd-configuration> seatd-configuration
   seatd-configuration?
   (seatd seatd-package (default seatd))
   (user seatd-user (default "root"))
-  (group seatd-group (default "users"))
+  (group seatd-group (default "seat"))
   (socket seatd-socket (default "/run/seatd.sock"))
   (logfile seatd-logfile (default "/var/log/seatd.log"))
   (loglevel seatd-loglevel (default "info")))
@@ -1670,6 +1670,9 @@ (define (seatd-shepherd-service config)
                    #:log-file #$(seatd-logfile config)))
          (stop #~(make-kill-destructor)))))
 
+(define %seatd-accounts
+  (list (user-group (name "seat") (system? #t))))
+
 (define seatd-environment
   (match-lambda
     (($ <seatd-configuration> _ _ _ socket)
@@ -1683,6 +1686,7 @@ (define seatd-service-type
 applications needing access to be root.")
    (extensions
     (list
+     (service-extension account-service-type (const %seatd-accounts))
      (service-extension session-environment-service-type seatd-environment)
      ;; TODO: once cgroups is separate dependency we should not mount it here
      ;; for now it is mounted here, because elogind mounts it
-- 
2.36.1