fix: ship polkit rule so greeter user can reboot/power off (v0.8.3)

The rule that grants the greeter user authorization for
org.freedesktop.login1.{reboot,power-off} lived only in the moonarch
repo and was never installed by any PKGBUILD. On a fresh install the
reboot/shutdown buttons silently failed because greetd's greeter
session is inactive in logind and polkit denies inactive sessions by
default.

Move the rule into the moongreet source tree where it belongs and
ship it via moongreet-git.

CLAUDE.md

@@ -1,7 +1,5 @@
 # Moongreet
 
-**Name**: Selene (Mondgöttin — passend zu Moon-greet)
-
 ## Projekt
 
 Moongreet ist ein greetd-Greeter für Wayland, gebaut mit Rust + gtk4-rs + gtk4-layer-shell.
@@ -47,7 +45,7 @@ cd pkg && makepkg -sf && sudo pacman -U moongreet-git-<version>-x86_64.pkg.tar.z
 - `fingerprint.rs` — fprintd D-Bus Probe (gio::DBusProxy) — Geräteerkennung und Enrollment-Check für UI-Feedback
 - `config.rs` — TOML-Config ([appearance] background, gtk-theme, fingerprint-enabled) + Wallpaper-Fallback + Blur-Validierung (finite, clamp 0–200)
 - `greeter.rs` — GTK4 UI (Overlay-Layout), Login-Flow via greetd IPC (Multi-Stage-Auth für fprintd), Faillock-Warnung, Avatar-Cache, Last-User/Last-Session Persistence (0o700 Dirs, 0o600 Files)
-- `main.rs` — Entry Point, GTK App, Layer Shell Setup, Multi-Monitor, systemd-journal-logger
+- `main.rs` — Entry Point, GTK App, Layer Shell Setup, Multi-Monitor mit Hotplug via `items-changed` auf Monitor-ListModel (one greeter window per monitor, first gets keyboard), systemd-journal-logger
 - `resources/style.css` — Catppuccin-inspiriertes Theme
 
 ## Design Decisions

Cargo.lock

@@ -575,7 +575,7 @@ dependencies = [
 
 [[package]]
 name = "moongreet"
-version = "0.7.1"
+version = "0.8.3"
 dependencies = [
  "gdk-pixbuf",
  "gdk4",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "moongreet"
-version = "0.7.1"
+version = "0.8.3"
 edition = "2024"
 description = "A greetd greeter for Wayland with GTK4 and Layer Shell"
 license = "MIT"

DECISIONS.md

@@ -1,49 +1,84 @@
 # Decisions
 
+## 2026-04-21 – Ship polkit rule in moongreet instead of moonarch (v0.8.3)
+
+- **Who**: ClaudeCode, Dom
+- **Why**: Reboot/shutdown from the greeter silently failed on a fresh install. The polkit rule that grants the `greeter` user `org.freedesktop.login1.{reboot,power-off}` lived in the moonarch repo but was never installed by any PKGBUILD. The laptop worked only because the rule had been hand-deployed once.
+- **Tradeoffs**: Rule ownership moves from moonarch (system defaults) to moongreet (greeter-specific auth). Cleaner boundary — moonarch no longer needs to know about the greeter's auth requirements — but it means moongreet is now responsible for a system polkit rule that ties it to a fixed username (`greeter`).
+- **How**: Source file moved to `moongreet/config/polkit/50-moongreet-power.rules`, installed to `/etc/polkit-1/rules.d/` by `moongreet-git/PKGBUILD`. Old file removed from the moonarch repo.
+
+## 2026-04-09 – Monitor hotplug via ListModel items-changed
+
+- **Who**: ClaudeCode, Dom
+- **Why**: Greeter windows were only created at startup. If a monitor was hotplugged (e.g. HDMI reconnect), it would show no greeter UI. Aligned with moonlock's hotplug fix (same day).
+- **Tradeoffs**: Hotplugged monitors get greeter windows without keyboard input (keyboard stays on the primary monitor). Acceptable — user can still interact on the primary screen.
+- **How**: Connect to `display.monitors().connect_items_changed()` and create new greeter windows for added monitors. Shared state (config, texture, blur_cache) moved to Rc for the closure.
+
+## 2026-04-08 – Show greeter UI on all monitors instead of just one
+
+- **Who**: ClaudeCode, Dom
+- **Why**: moonlock showed its UI on all monitors via ext-session-lock-v1, but moongreet only showed the login UI on one monitor (compositor-picked) with wallpaper-only windows on the rest. Inconsistent UX across the ecosystem.
+- **Tradeoffs**: Each monitor gets its own full greeter widget tree (slightly more memory), but the UI is lightweight. Screen mirroring (e.g., wl-mirror/screencopy) was considered and rejected — it requires an external process, compositor screencopy support, adds latency, and fights Wayland's per-output model. One-window-per-monitor is the established Wayland pattern (swaylock, hyprlock, moonlock all do this).
+- **How**: Create one `create_greeter_window()` per monitor with `set_monitor()`, only the first gets `KeyboardMode::Exclusive`. Removed `create_wallpaper_window()` (no longer needed). No layer shell fallback keeps single-window mode for development.
+
+## 2026-04-06 – Restore explicit gtk-theme in moongreet config
+
+- **Who**: ClaudeCode, Dom
+- **Why**: GTK4 under greetd does not reliably read `/etc/xdg/gtk-4.0/settings.ini` — likely requires a settings daemon that doesn't run in the greeter session. moongreet fell back to Adwaita/Colloid-default (blue accent) instead of Colloid-Grey-Dark-Catppuccin.
+- **Tradeoffs**: Reverts `094878f` ("Remove gtk-theme from app config, use system-wide GTK settings instead"). Duplicates the theme name between settings.ini and moongreet.toml, but the explicit set via `set_gtk_theme_name()` is the only reliable path in a greetd context.
+- **How**: Added `gtk-theme = "Colloid-Grey-Dark-Catppuccin"` to example config and deployed `/etc/moongreet/moongreet.toml`.
+
+## 2026-04-02 – Replace hardcoded CSS colors with GTK theme variables
+
+- **Who**: ClaudeCode, Dom
+- **Why**: moongreet used hardcoded colors (#1a1a2e, white, #ff6b6b) while moonset already used @theme_bg_color, @theme_fg_color, @error_color etc. Inconsistent across the ecosystem and broke theme flexibility.
+- **Tradeoffs**: Depends on the active GTK theme defining standard color variables. Catppuccin Colloid provides all needed vars (@theme_bg_color, @theme_fg_color, @error_color, @success_color, @theme_selected_bg_color). Fallback behavior if a theme lacks vars is GTK's default colors — acceptable.
+- **How**: Replaced all hardcoded hex/named colors with GTK theme variables. Coordinated change across moongreet, moonlock, and moonset (all three now use identical pattern).
+
 ## 2026-03-31 – Fourth audit: power timeout, timing mitigation, release profile, GREETD_SOCK caching
 
-- **Who**: Ragnar, Dom
+- **Who**: ClaudeCode, Dom
 - **Why**: Fourth triple audit found moongreet power.rs had no timeout on loginctl (greeter could freeze), username enumeration via timing differential, GREETD_SOCK re-read on every login, missing release profile, and missing GResource compression.
 - **Tradeoffs**: 500ms minimum login response time adds slight delay on fast auth but prevents timing-based username enumeration. Power timeout (30s + SIGKILL) matches moonset pattern — aggressive but prevents greeter freeze.
 - **How**: (1) power.rs adapted from moonset with 30s timeout + SIGKILL (nix dependency added). (2) 500ms min response floor in attempt_login via Instant + glib::timeout_future. (3) GREETD_SOCK cached in GreeterState at startup. (4) `[profile.release]` with LTO, codegen-units=1, strip. (5) `compressed="true"` on GResource entries. (6) SYNC comments on duplicated blur/background functions.
 
 ## 2026-03-30 – Full audit fix: security, quality, performance (v0.6.2)
 
-- **Who**: Ragnar, Dom
+- **Who**: ClaudeCode, Dom
 - **Why**: Three parallel audits (security, code quality, performance) identified 10 actionable findings across the codebase — from world-readable cache dirs to a GPU blur geometry bug to a race condition in fingerprint probing.
 - **Tradeoffs**: `too_many_arguments` Clippy warnings suppressed with `#[allow]` rather than introducing a `UiWidgets` struct — GTK's `clone!` macro with `#[weak]` refs requires individual widget parameters, a struct would fight the idiom. Async avatar loading skipped because `Pixbuf` is `!Send`; cache already prevents repeat loads. TOCTOU socket pre-check removed entirely — `connect()` in login_worker already handles errors, the `metadata()` check gave false security guarantees.
 - **How**: Cache dirs use `DirBuilder::mode(0o700)` instead of `create_dir_all`. Blur config clamped to `0.0..=200.0` with `is_finite()` guard. Blur texture cached in `Rc<RefCell<Option<gdk::Texture>>>` across monitors. FingerprintProbe device proxy cached in `GreeterState` with generation counter to prevent stale async writes. GPU blur geometry fixed (`-pad` origin shift instead of texture stretching). `is_valid_gtk_theme` extracted as testable function. 9 new tests.
 
 ## 2026-03-29 – Fingerprint authentication via greetd multi-stage PAM
 
-- **Who**: Ragnar, Dom
+- **Who**: ClaudeCode, Dom
 - **Why**: moonlock supports fprintd but moongreet rejected multi-stage auth. Users with enrolled fingerprints couldn't use them at the login screen.
 - **Tradeoffs**: Direct fprintd D-Bus verification (like moonlock) can't start a greetd session — greetd controls session creation via PAM. Using greetd multi-stage means PAM decides the auth order (fingerprint first, then password fallback), not truly parallel. Acceptable — matches standard pam_fprintd behavior.
 - **How**: Replace single-pass auth with a loop over auth_message rounds. Secret prompts get the password, non-secret prompts (fprintd) get None and block until PAM resolves. fprintd D-Bus probe (gio::DBusProxy) only for UI — detecting device availability and enrolled fingers. 60s socket timeout when fingerprint available. Config option `fingerprint-enabled` (default true).
 
 ## 2026-03-28 – Remove embedded wallpaper from binary
 
-- **Who**: Selene, Dom
+- **Who**: ClaudeCode, Dom
 - **Why**: Wallpaper is installed by moonarch to /usr/share/moonarch/wallpaper.jpg. Embedding a 374K JPEG in the binary is redundant. GTK background color (Catppuccin Mocha base) is a clean fallback.
 - **Tradeoffs**: Without moonarch installed AND without config, greeter shows plain dark background instead of wallpaper. Acceptable — that's the expected minimal state.
 - **How**: Remove wallpaper.jpg from GResources, return None from resolve_background_path when no file found, skip wallpaper window creation and background picture when no path available.
 
 ## 2026-03-28 – GPU blur via GskBlurNode replaces CPU blur
 
-- **Who**: Ragnar, Dom
+- **Who**: ClaudeCode, Dom
 - **Why**: CPU-side Gaussian blur (`image` crate) blocked the GTK main thread for 500ms–2s on 4K wallpapers at cold cache. Disk cache and async orchestration added significant complexity.
 - **Tradeoffs**: GPU blur quality is slightly different (box-blur approximation vs true Gaussian), acceptable for wallpaper backgrounds. Removes `image` crate dependency entirely (~15 transitive crates eliminated). No disk cache needed.
 - **How**: `Snapshot::push_blur()` + `GskRenderer::render_texture()` on `connect_realize`. Blur happens once on the GPU when the widget gets its renderer, producing a concrete `gdk::Texture`. Zero startup latency. Symmetric with moonlock and moonset.
 
 ## 2026-03-28 – Optional background blur via `image` crate (superseded)
 
-- **Who**: Selene, Dom
+- **Who**: ClaudeCode, Dom
 - **Why**: Blurred wallpaper as greeter background is a common UX pattern for login screens
 - **Tradeoffs**: Adds `image` crate dependency (~15 transitive crates); CPU-side Gaussian blur at load time adds startup latency proportional to image size and sigma. Acceptable because blur runs once and the texture is shared across monitors.
 - **How**: `load_background_texture(bg_path, blur_radius)` loads texture, optionally applies `imageops::blur()`, returns blurred `gdk::Texture`. Config option `background-blur: Option<f32>` in `[appearance]` TOML section.
 
 ## 2026-03-28 – Audit fixes for shared wallpaper texture (v0.4.1)
-- **Who**: Selene, Dominik
+- **Who**: ClaudeCode, Dominik
 - **Why**: Quality, performance, and security audits flagged issues in `load_background_texture()`, debug logging, and greetd error handling
 - **Tradeoffs**: GResource path now requires UTF-8 (returns `None` for non-UTF-8 instead of aborting); 50 MB wallpaper limit is generous but prevents OOM; debug logging off by default trades observability for security
 - **How**: GResource branch via `resources_lookup_data()` + `from_bytes()` (no abort), file size limit, error details only at debug level, `MOONGREET_DEBUG` env var for log level, greetd retry path truncation matching `show_greetd_error()`

README.md

@@ -12,7 +12,7 @@ Part of the Moonarch ecosystem.
 - **Last user/session** — Remembered in `/var/cache/moongreet/`
 - **Power actions** — Reboot / Shutdown via `loginctl`
 - **Layer Shell** — Fullscreen via gtk4-layer-shell (TOP layer)
-- **Multi-monitor** — Greeter on primary, wallpaper on all monitors
+- **Multi-monitor + hotplug** — Full greeter UI on all monitors (keyboard input on first), hotplugged monitors get windows automatically
 - **GPU blur** — Background blur via GskBlurNode (shared cache across monitors)
 - **i18n** — German and English (auto-detected from system locale)
 - **Faillock warning** — Warns after 2 failed attempts, locked message after 3
@@ -60,6 +60,14 @@ sudo cp config/moongreet.toml /etc/moongreet/moongreet.toml
    user = "greeter"
    ```
 
+4. Install the polkit rule so the greeter user can reboot / power off:
+   ```bash
+   sudo install -Dm644 config/polkit/50-moongreet-power.rules \
+       /etc/polkit-1/rules.d/50-moongreet-power.rules
+   ```
+   Without this rule, `loginctl reboot` / `loginctl poweroff` fail because
+   greetd's greeter session is inactive in logind.
+
 ## Development
 
 ```bash

config/moongreet.toml

@@ -4,5 +4,7 @@
 [appearance]
 # Absolute path to wallpaper image
 background = "/usr/share/backgrounds/wallpaper.jpg"
-# GTK theme for the greeter UI
+
+# GTK theme name — must match a directory in /usr/share/themes/
+# Required because GTK4 under greetd does not reliably read settings.ini
 gtk-theme = "Colloid-Grey-Dark-Catppuccin"

config/polkit/50-moongreet-power.rules

@@ -0,0 +1,12 @@
+// ABOUTME: Allow the greeter user to reboot and power off without authentication.
+// ABOUTME: Required because greetd's greeter session is inactive in logind.
+
+polkit.addRule(function(action, subject) {
+    if (subject.user === "greeter" &&
+        (action.id === "org.freedesktop.login1.reboot" ||
+         action.id === "org.freedesktop.login1.reboot-multiple-sessions" ||
+         action.id === "org.freedesktop.login1.power-off" ||
+         action.id === "org.freedesktop.login1.power-off-multiple-sessions")) {
+        return polkit.Result.YES;
+    }
+});

resources/style.css

@@ -1,16 +1,16 @@
 /* ABOUTME: GTK4 CSS stylesheet for the Moongreet greeter. */
-/* ABOUTME: Defines styling for the login screen layout. */
+/* ABOUTME: Uses GTK theme colors for consistency with the active desktop theme. */
 
 /* Main window background */
 window.greeter {
-    background-color: #1a1a2e;
+    background-color: @theme_bg_color;
     background-size: cover;
     background-position: center;
 }
 
 /* Wallpaper-only window for secondary monitors */
 window.wallpaper {
-    background-color: #1a1a2e;
+    background-color: @theme_bg_color;
 }
 
 /* Central login area */
@@ -26,14 +26,14 @@ window.wallpaper {
     min-width: 128px;
     min-height: 128px;
     background-color: @theme_selected_bg_color;
-    border: 3px solid alpha(white, 0.3);
+    border: 3px solid alpha(@theme_fg_color, 0.3);
 }
 
 /* Username label */
 .username-label {
     font-size: 24px;
     font-weight: bold;
-    color: white;
+    color: @theme_fg_color;
     margin-top: 12px;
     margin-bottom: 40px;
 }
@@ -50,13 +50,13 @@ window.wallpaper {
 
 /* Error message label */
 .error-label {
-    color: #ff6b6b;
+    color: @error_color;
     font-size: 14px;
 }
 
 /* Fingerprint prompt label */
 .fingerprint-label {
-    color: alpha(white, 0.6);
+    color: alpha(@theme_fg_color, 0.6);
     font-size: 13px;
     margin-top: 8px;
 }
@@ -70,16 +70,16 @@ window.wallpaper {
 .user-list-item {
     padding: 8px 16px;
     border-radius: 8px;
-    color: white;
+    color: @theme_fg_color;
     font-size: 14px;
 }
 
 .user-list-item:hover {
-    background-color: alpha(white, 0.15);
+    background-color: alpha(@theme_fg_color, 0.15);
 }
 
 .user-list-item:selected {
-    background-color: alpha(white, 0.2);
+    background-color: alpha(@theme_fg_color, 0.2);
 }
 
 /* Power buttons on the bottom right */
@@ -88,12 +88,12 @@ window.wallpaper {
     min-height: 48px;
     padding: 0px;
     border-radius: 24px;
-    background-color: alpha(white, 0.1);
-    color: white;
+    background-color: alpha(@theme_fg_color, 0.1);
+    color: @theme_fg_color;
     border: none;
     margin: 4px;
 }
 
 .power-button:hover {
-    background-color: alpha(white, 0.25);
+    background-color: alpha(@theme_fg_color, 0.25);
 }

src/greeter.rs

@@ -188,24 +188,6 @@ fn render_blurred_texture(
     Some(renderer.render_texture(&node, Some(&viewport)))
 }
 
-/// Create a wallpaper-only window for secondary monitors.
-pub fn create_wallpaper_window(
-    texture: &gdk::Texture,
-    blur_radius: Option<f32>,
-    blur_cache: &Rc<RefCell<Option<gdk::Texture>>>,
-    app: &gtk::Application,
-) -> gtk::ApplicationWindow {
-    let window = gtk::ApplicationWindow::builder()
-        .application(app)
-        .build();
-    window.add_css_class("wallpaper");
-
-    let background = create_background_picture(texture, blur_radius, blur_cache);
-    window.set_child(Some(&background));
-
-    window
-}
-
 /// Create a Picture widget for the wallpaper background, optionally with GPU blur.
 /// Uses `blur_cache` to compute the blurred texture only once across all monitors.
 fn create_background_picture(
@@ -553,6 +535,18 @@ pub fn create_greeter_window(
     ));
     window.add_controller(key_controller);
 
+    // Grab keyboard focus after map — layer-shell keyboard grab is only
+    // confirmed by the compositor at map time, not at realize time.
+    window.connect_map(clone!(
+        #[weak]
+        password_entry,
+        move |_| {
+            glib::idle_add_local_once(move || {
+                password_entry.grab_focus();
+            });
+        }
+    ));
+
     // Defer initial user selection until realized (for correct theme colors)
     window.connect_realize(clone!(
         #[strong]

src/main.rs

@@ -11,9 +11,11 @@ mod sessions;
 mod users;
 
 use gdk4 as gdk;
+use glib::clone;
 use gtk4::prelude::*;
 use gtk4::{self as gtk, gio};
 use gtk4_layer_shell::LayerShell;
+use std::rc::Rc;
 fn load_css(display: &gdk::Display) {
     let css_provider = gtk::CssProvider::new();
     css_provider.load_from_resource("/dev/moonarch/moongreet/style.css");
@@ -63,30 +65,54 @@ fn activate(app: &gtk::Application) {
     let use_layer_shell = std::env::var("MOONGREET_NO_LAYER_SHELL").is_err();
     log::debug!("Layer shell: {use_layer_shell}");
 
-    // Main greeter window (login UI) — compositor picks focused monitor
-    let greeter_window = greeter::create_greeter_window(bg_texture.as_ref(), &config, &blur_cache, app);
     if use_layer_shell {
-        setup_layer_shell(&greeter_window, true, gtk4_layer_shell::Layer::Top);
-    }
-    greeter_window.present();
-
-    // Wallpaper-only windows on all monitors (only with layer shell)
-    if use_layer_shell
-        && let Some(ref texture) = bg_texture
-    {
+        // One greeter window per monitor — only the first gets keyboard input
         let monitors = display.monitors();
         log::debug!("Monitor count: {}", monitors.n_items());
+        let mut first = true;
         for i in 0..monitors.n_items() {
             if let Some(monitor) = monitors
                 .item(i)
                 .and_then(|obj| obj.downcast::<gdk::Monitor>().ok())
             {
-                let wallpaper = greeter::create_wallpaper_window(texture, config.background_blur, &blur_cache, app);
-                setup_layer_shell(&wallpaper, false, gtk4_layer_shell::Layer::Bottom);
-                wallpaper.set_monitor(Some(&monitor));
-                wallpaper.present();
+                let window = greeter::create_greeter_window(bg_texture.as_ref(), &config, &blur_cache, app);
+                setup_layer_shell(&window, first, gtk4_layer_shell::Layer::Top);
+                window.set_monitor(Some(&monitor));
+                window.present();
+                first = false;
             }
         }
+
+        // Handle monitor hotplug — create greeter windows for newly added monitors
+        // (without keyboard, since the primary monitor already has it)
+        let bg_texture = Rc::new(bg_texture);
+        let config = Rc::new(config);
+        monitors.connect_items_changed(clone!(
+            #[weak]
+            app,
+            #[strong]
+            blur_cache,
+            move |list, position, _removed, added| {
+                for i in position..position + added {
+                    if let Some(monitor) = list
+                        .item(i)
+                        .and_then(|obj| obj.downcast::<gdk::Monitor>().ok())
+                    {
+                        log::debug!("Monitor hotplug: creating greeter window");
+                        let window = greeter::create_greeter_window(
+                            bg_texture.as_ref().as_ref(), &config, &blur_cache, &app,
+                        );
+                        setup_layer_shell(&window, false, gtk4_layer_shell::Layer::Top);
+                        window.set_monitor(Some(&monitor));
+                        window.present();
+                    }
+                }
+            }
+        ));
+    } else {
+        // No layer shell — single window for development
+        let greeter_window = greeter::create_greeter_window(bg_texture.as_ref(), &config, &blur_cache, app);
+        greeter_window.present();
     }
 }