Use systemd sysusers config to create user and group

See: https://docs.fedoraproject.org/en-US/packaging-guidelines/UsersAndGroups/

gdm.spec

@@ -11,7 +11,7 @@
 Name: gdm
 Epoch: 1
 Version: 41.0
-Release: 1%{?dist}
+Release: 2%{?dist}
 Summary: The GNOME Display Manager
 
 License: GPLv2+
@@ -22,6 +22,8 @@ Source1: org.gnome.login-screen.gschema.override
 # moved here from pulseaudio-gdm-hooks-11.1-16
 Source5: default.pa-for-gdm
 
+Source6: gdm.sysusers
+
 # Downstream patches
 Patch80001: 0001-Honor-initial-setup-being-disabled-by-distro-install.patch
 Patch90001: 0001-data-add-system-dconf-databases-to-gdm-profile.patch
@@ -140,6 +142,7 @@ mkdir -p %{buildroot}%{_sysconfdir}/gdm/PostSession
 %meson_install
 
 install -p -m644 -D %{SOURCE5} %{buildroot}%{_localstatedir}/lib/gdm/.config/pulse/default.pa
+install -p -m644 -D %{SOURCE6} %{buildroot}%{_sysusersdir}/%{name}.conf
 
 rm -f %{buildroot}%{_sysconfdir}/pam.d/gdm
 
@@ -163,11 +166,7 @@ mkdir -p %{buildroot}%{_sysconfdir}/dconf/db/gdm.d/locks
 %find_lang gdm --with-gnome
 
 %pre
-/usr/sbin/useradd -M -u 42 -d /var/lib/gdm -s /sbin/nologin -r gdm > /dev/null 2>&1
-/usr/sbin/usermod -d /var/lib/gdm -s /sbin/nologin gdm >/dev/null 2>&1
-# ignore errors, as we can't disambiguate between gdm already existed
-# and couldn't create account with the current adduser.
-exit 0
+sysusers_create_compat %{SOURCE6}
 
 %post
 # if the user already has a config file, then migrate it to the new
@@ -286,6 +285,7 @@ fi
 %{_unitdir}/gdm.service
 %dir %{_userunitdir}/gnome-session@gnome-login.target.d/
 %{_userunitdir}/gnome-session@gnome-login.target.d/session.conf
+%{_sysusersdir}/%{name}.conf
 
 %files devel
 %dir %{_includedir}/gdm
@@ -300,6 +300,9 @@ fi
 %{_libdir}/pkgconfig/gdm-pam-extensions.pc
 
 %changelog
+* Fri Oct 15 2021 Timothée Ravier <tim@siosm.fr> - 1:41.0-2
+- Use systemd sysusers config to create user and group
+
 * Tue Sep 21 2021 Kalev Lember <klember@redhat.com> - 1:41.0-1
 - Update to 41.0
 

gdm.sysusers

@@ -0,0 +1 @@
+u gdm 42 "GNOME Display Manager" /var/lib/gdm