Use X11 greeter for Linux RustDesk access

scripts/Install-SguLinuxRustDeskClient.sh

@@ -218,6 +218,89 @@ EOF
     wait_for_rustdesk_server
 }
 
+configure_x11_login_screen() {
+    local display_manager=''
+    local configuration_changed=false
+    local configuration_path=''
+    local temporary_configuration=''
+
+    if [[ -L /etc/systemd/system/display-manager.service ]]; then
+        display_manager=$(basename "$(readlink -f /etc/systemd/system/display-manager.service)")
+    fi
+
+    case "$display_manager" in
+        gdm3.service|gdm.service)
+            if [[ $display_manager == gdm3.service ]]; then
+                configuration_path='/etc/gdm3/custom.conf'
+            else
+                configuration_path='/etc/gdm/custom.conf'
+            fi
+            install -d -o root -g root -m 755 "$(dirname "$configuration_path")"
+            [[ -f $configuration_path ]] || printf '[daemon]\n' >"$configuration_path"
+            temporary_configuration=$(mktemp)
+            python3 - "$configuration_path" "$temporary_configuration" <<'PY'
+import re
+import sys
+from pathlib import Path
+
+source = Path(sys.argv[1])
+destination = Path(sys.argv[2])
+lines = source.read_text(encoding='utf-8').splitlines()
+daemon_start = None
+daemon_end = len(lines)
+for index, line in enumerate(lines):
+    if re.match(r'^\s*\[daemon\]\s*$', line, re.IGNORECASE):
+        daemon_start = index
+        continue
+    if daemon_start is not None and index > daemon_start and re.match(r'^\s*\[[^]]+\]\s*$', line):
+        daemon_end = index
+        break
+
+if daemon_start is None:
+    if lines and lines[-1]:
+        lines.append('')
+    lines.extend(['[daemon]', 'WaylandEnable=false'])
+else:
+    setting = re.compile(r'^\s*[#;]?\s*WaylandEnable\s*=.*$', re.IGNORECASE)
+    for index in range(daemon_start + 1, daemon_end):
+        if setting.match(lines[index]):
+            lines[index] = 'WaylandEnable=false'
+            break
+    else:
+        lines.insert(daemon_end, 'WaylandEnable=false')
+
+destination.write_text('\n'.join(lines) + '\n', encoding='utf-8')
+PY
+            if ! cmp -s "$temporary_configuration" "$configuration_path"; then
+                install -o root -g root -m 644 "$temporary_configuration" "$configuration_path"
+                configuration_changed=true
+            fi
+            rm -f "$temporary_configuration"
+            ;;
+        sddm.service)
+            configuration_path='/etc/sddm.conf.d/91-sgu-rustdesk-x11.conf'
+            install -d -o root -g root -m 755 "$(dirname "$configuration_path")"
+            temporary_configuration=$(mktemp)
+            printf '%s\n' '[General]' 'DisplayServer=x11' >"$temporary_configuration"
+            if ! cmp -s "$temporary_configuration" "$configuration_path"; then
+                install -o root -g root -m 644 "$temporary_configuration" "$configuration_path"
+                configuration_changed=true
+            fi
+            rm -f "$temporary_configuration"
+            ;;
+        lightdm.service)
+            # LightDM's greeter already runs on X11, which RustDesk supports.
+            ;;
+        *)
+            printf 'WARNING: Could not identify a supported display manager; RustDesk login-screen access may require X11 configuration.\n' >&2
+            ;;
+    esac
+
+    if [[ $configuration_changed == true ]]; then
+        printf 'RustDesk login-screen support was configured for X11; reboot after enrollment to activate it.\n'
+    fi
+}
+
 wait_for_rustdesk_server() {
     local attempt
     local candidate_id
@@ -326,6 +409,7 @@ resolve_registration_share
 initialize_machine_kerberos
 install_rustdesk
 read_server_configuration
+configure_x11_login_screen
 configure_rustdesk
 set_access_password
 register_with_controller