feat: add fprintd fingerprint authentication via greetd multi-stage PAM (v0.6.0)

Fingerprint auth was missing because moongreet rejected multi-stage
auth_message sequences from greetd. With pam_fprintd.so in the PAM
stack, greetd sends non-secret prompts for fingerprint and secret
prompts for password — moongreet now handles both in a loop.

- Replace single-pass auth with multi-stage auth_message loop
- fprintd D-Bus probe (gio::DBusProxy) for UI feedback only
- Fingerprint label shown when device available and fingers enrolled
- 60s socket timeout when fingerprint available (pam_fprintd scan time)
- Config option: [appearance] fingerprint-enabled (default: true)
- Fix: password entry focus loss after auth error (grab_focus while
  widget was insensitive — now re-enable before grab_focus)

CLAUDE.md

@@ -17,8 +17,9 @@ Teil des Moonarch-Ökosystems.
 ## Projektstruktur
 
 - `src/` — Rust-Quellcode (main.rs, greeter.rs, ipc.rs, config.rs, users.rs, sessions.rs, i18n.rs, power.rs)
-- `resources/` — GResource-Assets (style.css, wallpaper.jpg, default-avatar.svg)
+- `resources/` — GResource-Assets (style.css, default-avatar.svg)
 - `config/` — Beispiel-Konfigurationsdateien für `/etc/moongreet/` und `/etc/greetd/`
+- `pkg/` — PKGBUILD für Arch-Linux-Paketierung (`makepkg -sf`)
 
 ## Kommandos
 
@@ -29,8 +30,11 @@ cargo test
 # Release-Build
 cargo build --release
 
-# Greeter starten (nur zum Testen, braucht normalerweise greetd)
-LD_PRELOAD=/usr/lib/libgtk4-layer-shell.so ./target/release/moongreet
+# Greeter im Fenster starten (ohne greetd/Layer Shell)
+MOONGREET_NO_LAYER_SHELL=1 ./target/release/moongreet
+
+# Paket bauen und installieren
+cd pkg && makepkg -sf && sudo pacman -U moongreet-git-<version>-x86_64.pkg.tar.zst
 ```
 
 ## Architektur
@@ -39,10 +43,11 @@ LD_PRELOAD=/usr/lib/libgtk4-layer-shell.so ./target/release/moongreet
 - `users.rs` — Benutzer aus /etc/passwd, Avatare (AccountsService + ~/.face), Symlink-Rejection
 - `sessions.rs` — Wayland/X11 Sessions aus .desktop Files
 - `power.rs` — Reboot/Shutdown via loginctl
-- `i18n.rs` — Locale-Erkennung (LANG / /etc/locale.conf) und String-Tabellen (DE/EN)
-- `config.rs` — TOML-Config ([appearance] background, gtk-theme) + Wallpaper-Fallback
-- `greeter.rs` — GTK4 UI (Overlay-Layout), Login-Flow via greetd IPC, Faillock-Warnung, Avatar-Cache, Last-User/Last-Session Persistence
-- `main.rs` — Entry Point, GTK App, Layer Shell Setup, Multi-Monitor
+- `i18n.rs` — Locale-Erkennung (LANG / /etc/locale.conf) und String-Tabellen (DE/EN), alle UI- und Login-Fehlermeldungen
+- `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
+- `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 (0o600 Permissions)
+- `main.rs` — Entry Point, GTK App, Layer Shell Setup, Multi-Monitor, systemd-journal-logger
 - `resources/style.css` — Catppuccin-inspiriertes Theme
 
 ## Design Decisions
@@ -52,4 +57,14 @@ LD_PRELOAD=/usr/lib/libgtk4-layer-shell.so ./target/release/moongreet
 - **Async Login**: `glib::spawn_future_local` + `gio::spawn_blocking` statt raw Threads
 - **Socket-Cancellation**: `Arc<Mutex<Option<UnixStream>>>` + `AtomicBool` für saubere Abbrüche
 - **Avatar-Cache**: `HashMap<String, gdk::Texture>` in `Rc<RefCell<GreeterState>>`
-- **Symmetrie mit moonset**: Gleiche Patterns (i18n, config, users, power, GResource)
+- **GPU-Blur via GskBlurNode**: `Snapshot::push_blur()` + `GskRenderer::render_texture()` im `connect_realize` Callback — kein CPU-Blur, kein Disk-Cache, kein `image`-Crate
+- **Fingerprint via greetd Multi-Stage PAM**: fprintd D-Bus nur als Probe (Gerät/Enrollment), eigentliche Verifizierung läuft über PAM im greetd-Auth-Loop. `auth_message_type: "secret"` → Passwort, alles andere → `None` (PAM entscheidet). 60s Socket-Timeout bei fprintd.
+- **Symmetrie mit moonlock/moonset**: Gleiche Patterns (i18n, config, users, power, GResource, GPU-Blur)
+- **Session-Validierung**: Relative Pfade erlaubt (greetd löst PATH auf), nur `..`/Null-Bytes werden abgelehnt
+- **GTK-Theme-Validierung**: Nur alphanumerisch + `_-+.` erlaubt, verhindert Path-Traversal über Config
+- **Journal-Logging**: `systemd-journal-logger` statt File-Logging — `journalctl -t moongreet`, Debug-Level per `MOONGREET_DEBUG` Env-Var
+- **File Permissions**: Cache-Dateien 0o600
+- **Testbare Persistence**: `save_*_to`/`load_*_from` Varianten mit konfigurierbarem Pfad für Unit-Tests
+- **Shared Wallpaper Texture**: `gdk::Texture` wird einmal in `load_background_texture()` dekodiert und per Ref-Count an alle Fenster geteilt — vermeidet redundante JPEG-Dekodierung pro Monitor
+- **Wallpaper-Validierung**: GResource-Zweig via `resources_lookup_data()` + `from_bytes()` (kein Abort bei fehlendem Pfad), Dateigröße-Limit 50 MB, non-UTF-8-Pfade → `None`
+- **Error-Detail-Filterung**: GDK/greetd-Fehlerdetails nur auf `debug!`-Level, `warn!` ohne interne Details — verhindert Systeminfo-Leak ins Journal

Cargo.lock

@@ -2,65 +2,6 @@
 # It is not intended for manual editing.
 version = 4
 
-[[package]]
-name = "aho-corasick"
-version = "1.1.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ddd31a130427c27518df266943a5308ed92d4b226cc639f5a8f1002816174301"
-dependencies = [
- "memchr",
-]
-
-[[package]]
-name = "anstream"
-version = "1.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "824a212faf96e9acacdbd09febd34438f8f711fb84e09a8916013cd7815ca28d"
-dependencies = [
- "anstyle",
- "anstyle-parse",
- "anstyle-query",
- "anstyle-wincon",
- "colorchoice",
- "is_terminal_polyfill",
- "utf8parse",
-]
-
-[[package]]
-name = "anstyle"
-version = "1.0.14"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "940b3a0ca603d1eade50a4846a2afffd5ef57a9feac2c0e2ec2e14f9ead76000"
-
-[[package]]
-name = "anstyle-parse"
-version = "1.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "52ce7f38b242319f7cabaa6813055467063ecdc9d355bbb4ce0c68908cd8130e"
-dependencies = [
- "utf8parse",
-]
-
-[[package]]
-name = "anstyle-query"
-version = "1.1.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "40c48f72fd53cd289104fc64099abca73db4166ad86ea0b4341abe65af83dadc"
-dependencies = [
- "windows-sys",
-]
-
-[[package]]
-name = "anstyle-wincon"
-version = "3.0.11"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "291e6a250ff86cd4a820112fb8898808a366d8f9f58ce16d1f538353ad55747d"
-dependencies = [
- "anstyle",
- "once_cell_polyfill",
- "windows-sys",
-]
-
 [[package]]
 name = "anyhow"
 version = "1.0.102"
@@ -118,35 +59,6 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
-[[package]]
-name = "colorchoice"
-version = "1.0.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1d07550c9036bf2ae0c684c4297d503f838287c83c53686d05370d0e139ae570"
-
-[[package]]
-name = "env_filter"
-version = "1.0.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "32e90c2accc4b07a8456ea0debdc2e7587bdd890680d71173a15d4ae604f6eef"
-dependencies = [
- "log",
- "regex",
-]
-
-[[package]]
-name = "env_logger"
-version = "0.11.10"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0621c04f2196ac3f488dd583365b9c09be011a4ab8b9f37248ffcc8f6198b56a"
-dependencies = [
- "anstream",
- "anstyle",
- "env_filter",
- "jiff",
- "log",
-]
-
 [[package]]
 name = "equivalent"
 version = "1.0.2"
@@ -604,42 +516,12 @@ dependencies = [
  "serde_core",
 ]
 
-[[package]]
-name = "is_terminal_polyfill"
-version = "1.70.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a6cb138bb79a146c1bd460005623e142ef0181e3d0219cb493e02f7d08a35695"
-
 [[package]]
 name = "itoa"
 version = "1.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8f42a60cbdf9a97f5d2305f08a87dc4e09308d1276d28c869c684d7777685682"
 
-[[package]]
-name = "jiff"
-version = "0.2.23"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1a3546dc96b6d42c5f24902af9e2538e82e39ad350b0c766eb3fbf2d8f3d8359"
-dependencies = [
- "jiff-static",
- "log",
- "portable-atomic",
- "portable-atomic-util",
- "serde_core",
-]
-
-[[package]]
-name = "jiff-static"
-version = "0.2.23"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2a8c8b344124222efd714b73bb41f8b5120b27a7cc1c75593a6ff768d9d05aa4"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
-]
-
 [[package]]
 name = "khronos_api"
 version = "3.1.0"
@@ -687,19 +569,20 @@ dependencies = [
 
 [[package]]
 name = "moongreet"
-version = "0.3.0"
+version = "0.5.3"
 dependencies = [
- "env_logger",
  "gdk-pixbuf",
  "gdk4",
  "gio",
  "glib",
  "glib-build-tools",
+ "graphene-rs",
  "gtk4",
  "gtk4-layer-shell",
  "log",
  "serde",
  "serde_json",
+ "systemd-journal-logger",
  "tempfile",
  "toml 0.8.23",
 ]
@@ -710,12 +593,6 @@ version = "1.21.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9f7c3e4beb33f85d45ae3e3a1792185706c8e16d043238c593331cc7cd313b50"
 
-[[package]]
-name = "once_cell_polyfill"
-version = "1.70.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "384b8ab6d37215f3c5301a95a4accb5d64aa607f1fcb26a11b5303878451b4fe"
-
 [[package]]
 name = "pango"
 version = "0.22.0"
@@ -752,21 +629,6 @@ version = "0.3.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7edddbd0b52d732b21ad9a5fab5c704c14cd949e5e9a1ec5929a24fded1b904c"
 
-[[package]]
-name = "portable-atomic"
-version = "1.13.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c33a9471896f1c69cecef8d20cbe2f7accd12527ce60845ff44c153bb2a21b49"
-
-[[package]]
-name = "portable-atomic-util"
-version = "0.2.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "091397be61a01d4be58e7841595bd4bfedb15f1cd54977d79b8271e94ed799a3"
-dependencies = [
- "portable-atomic",
-]
-
 [[package]]
 name = "prettyplease"
 version = "0.2.37"
@@ -810,35 +672,6 @@ version = "6.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f8dcc9c7d52a811697d2151c701e0d08956f92b0e24136cf4cf27b57a6a0d9bf"
 
-[[package]]
-name = "regex"
-version = "1.12.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e10754a14b9137dd7b1e3e5b0493cc9171fdd105e0ab477f51b72e7f3ac0e276"
-dependencies = [
- "aho-corasick",
- "memchr",
- "regex-automata",
- "regex-syntax",
-]
-
-[[package]]
-name = "regex-automata"
-version = "0.4.14"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6e1dd4122fc1595e8162618945476892eefca7b88c52820e74af6262213cae8f"
-dependencies = [
- "aho-corasick",
- "memchr",
- "regex-syntax",
-]
-
-[[package]]
-name = "regex-syntax"
-version = "0.8.10"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dc897dd8d9e8bd1ed8cdad82b5966c3e0ecae09fb1907d58efaa013543185d0a"
-
 [[package]]
 name = "rustc_version"
 version = "0.4.1"
@@ -964,6 +797,16 @@ dependencies = [
  "version-compare",
 ]
 
+[[package]]
+name = "systemd-journal-logger"
+version = "2.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7266304d24ca5a4b230545fc558c80e18bd3e1d2eb1be149b6bcd04398d3e79c"
+dependencies = [
+ "log",
+ "rustix",
+]
+
 [[package]]
 name = "target-lexicon"
 version = "0.13.3"
@@ -1096,12 +939,6 @@ version = "0.2.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ebc1c04c71510c7f702b52b7c350734c9ff1295c464a03335b00bb84fc54f853"
 
-[[package]]
-name = "utf8parse"
-version = "0.2.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
-
 [[package]]
 name = "version-compare"
 version = "0.2.1"

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "moongreet"
-version = "0.3.1"
+version = "0.6.0"
 edition = "2024"
 description = "A greetd greeter for Wayland with GTK4 and Layer Shell"
 license = "MIT"
@@ -15,8 +15,9 @@ gio = "0.22"
 toml = "0.8"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
+graphene-rs = { version = "0.22", package = "graphene-rs" }
 log = "0.4"
-env_logger = "0.11"
+systemd-journal-logger = "2.2"
 
 [dev-dependencies]
 tempfile = "3"

DECISIONS.md

@@ -0,0 +1,35 @@
+# Decisions
+
+## 2026-03-29 – Fingerprint authentication via greetd multi-stage PAM
+
+- **Who**: Ragnar, 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
+- **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
+- **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
+- **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
+- **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

@@ -15,6 +15,7 @@ Part of the Moonarch ecosystem.
 - **Multi-monitor** — Greeter on primary, wallpaper on all monitors
 - **i18n** — German and English (auto-detected from system locale)
 - **Faillock warning** — Warns after 2 failed attempts, locked message after 3
+- **Fingerprint** — fprintd support via greetd multi-stage PAM (configurable)
 
 ## Requirements
 

config/moongreet.toml

@@ -5,4 +5,4 @@
 # Absolute path to wallpaper image
 background = "/usr/share/backgrounds/wallpaper.jpg"
 # GTK theme for the greeter UI
-gtk-theme = "catppuccin-mocha-lavender-standard+default"
+gtk-theme = "Colloid-Catppuccin"

pkg/PKGBUILD

@@ -4,7 +4,7 @@
 # Maintainer: Dominik Kressler
 
 pkgname=moongreet-git
-pkgver=0.3.0.r0.g0000000
+pkgver=0.3.1.r5.g4c9b436
 pkgrel=1
 pkgdesc="A greetd greeter for Wayland with GTK4 and Layer Shell"
 arch=('x86_64')

resources/resources.gresource.xml

@@ -2,7 +2,6 @@
 <gresources>
   <gresource prefix="/dev/moonarch/moongreet">
     <file>style.css</file>
-    <file>wallpaper.jpg</file>
     <file>default-avatar.svg</file>
   </gresource>
 </gresources>

resources/style.css

@@ -54,6 +54,13 @@ window.wallpaper {
     font-size: 14px;
 }
 
+/* Fingerprint prompt label */
+.fingerprint-label {
+    color: alpha(white, 0.6);
+    font-size: 13px;
+    margin-top: 8px;
+}
+
 /* User list on the bottom left */
 .user-list {
     background-color: transparent;

src/config.rs

@@ -6,7 +6,6 @@ use std::fs;
 use std::path::{Path, PathBuf};
 
 const MOONARCH_WALLPAPER: &str = "/usr/share/moonarch/wallpaper.jpg";
-const GRESOURCE_PREFIX: &str = "/dev/moonarch/moongreet";
 
 /// Default config search path: system-wide config.
 fn default_config_paths() -> Vec<PathBuf> {
@@ -22,15 +21,32 @@ struct TomlConfig {
 #[derive(Debug, Clone, Default, Deserialize)]
 struct Appearance {
     background: Option<String>,
+    #[serde(rename = "background-blur")]
+    background_blur: Option<f32>,
     #[serde(rename = "gtk-theme")]
     gtk_theme: Option<String>,
+    #[serde(rename = "fingerprint-enabled")]
+    fingerprint_enabled: Option<bool>,
 }
 
 /// Greeter configuration.
-#[derive(Debug, Clone, Default)]
+#[derive(Debug, Clone)]
 pub struct Config {
     pub background_path: Option<String>,
+    pub background_blur: Option<f32>,
     pub gtk_theme: Option<String>,
+    pub fingerprint_enabled: bool,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Config {
+            background_path: None,
+            background_blur: None,
+            gtk_theme: None,
+            fingerprint_enabled: true,
+        }
+    }
 }
 
 /// Load config from TOML files. Later paths override earlier ones.
@@ -40,8 +56,11 @@ pub fn load_config(config_paths: Option<&[PathBuf]>) -> Config {
 
     let mut merged = Config::default();
     for path in paths {
-        if let Ok(content) = fs::read_to_string(path) {
-            if let Ok(parsed) = toml::from_str::<TomlConfig>(&content) {
+        match fs::read_to_string(path) {
+            Ok(content) => {
+                match toml::from_str::<TomlConfig>(&content) {
+                    Ok(parsed) => {
+                        log::debug!("Config loaded: {}", path.display());
                         if let Some(appearance) = parsed.appearance {
                             if let Some(bg) = appearance.background {
                                 // Resolve relative paths against config file directory
@@ -53,41 +72,59 @@ pub fn load_config(config_paths: Option<&[PathBuf]>) -> Config {
                                         Some(parent.join(&bg).to_string_lossy().to_string());
                                 }
                             }
+                            if appearance.background_blur.is_some() {
+                                merged.background_blur = appearance.background_blur;
+                            }
                             if appearance.gtk_theme.is_some() {
                                 merged.gtk_theme = appearance.gtk_theme;
                             }
+                            if let Some(fp) = appearance.fingerprint_enabled {
+                                merged.fingerprint_enabled = fp;
                             }
                         }
                     }
+                    Err(e) => {
+                        log::warn!("Config parse error in {}: {e}", path.display());
+                    }
+                }
+            }
+            Err(_) => {
+                log::debug!("Config not found: {}", path.display());
+            }
+        }
     }
 
+    log::debug!("Config result: background={:?}, blur={:?}, gtk_theme={:?}, fingerprint={}", merged.background_path, merged.background_blur, merged.gtk_theme, merged.fingerprint_enabled);
     merged
 }
 
 /// Resolve the wallpaper path using the fallback hierarchy.
 ///
-/// Priority: config background_path > Moonarch system default > gresource fallback.
-pub fn resolve_background_path(config: &Config) -> PathBuf {
+/// Priority: config background_path > Moonarch system default > None (GTK background color).
+pub fn resolve_background_path(config: &Config) -> Option<PathBuf> {
     resolve_background_path_with(config, Path::new(MOONARCH_WALLPAPER))
 }
 
 /// Resolve with configurable moonarch wallpaper path (for testing).
-pub fn resolve_background_path_with(config: &Config, moonarch_wallpaper: &Path) -> PathBuf {
+pub fn resolve_background_path_with(config: &Config, moonarch_wallpaper: &Path) -> Option<PathBuf> {
     // User-configured path
     if let Some(ref bg) = config.background_path {
         let path = PathBuf::from(bg);
         if path.is_file() {
-            return path;
+            log::debug!("Wallpaper: using config path {}", path.display());
+            return Some(path);
         }
+        log::debug!("Wallpaper: config path {} not found, trying fallbacks", path.display());
     }
 
     // Moonarch ecosystem default
     if moonarch_wallpaper.is_file() {
-        return moonarch_wallpaper.to_path_buf();
+        log::debug!("Wallpaper: using moonarch default {}", moonarch_wallpaper.display());
+        return Some(moonarch_wallpaper.to_path_buf());
     }
 
-    // GResource fallback path (loaded from compiled resources at runtime)
-    PathBuf::from(format!("{GRESOURCE_PREFIX}/wallpaper.jpg"))
+    log::debug!("Wallpaper: no wallpaper found, using GTK background color");
+    None
 }
 
 #[cfg(test)]
@@ -98,7 +135,9 @@ mod tests {
     fn default_config_has_none_fields() {
         let config = Config::default();
         assert!(config.background_path.is_none());
+        assert!(config.background_blur.is_none());
         assert!(config.gtk_theme.is_none());
+        assert!(config.fingerprint_enabled);
     }
 
     #[test]
@@ -115,7 +154,7 @@ mod tests {
         let conf = dir.path().join("moongreet.toml");
         fs::write(
             &conf,
-            "[appearance]\nbackground = \"/custom/wallpaper.jpg\"\ngtk-theme = \"catppuccin\"\n",
+            "[appearance]\nbackground = \"/custom/wallpaper.jpg\"\nbackground-blur = 20.0\ngtk-theme = \"catppuccin\"\n",
         )
         .unwrap();
         let paths = vec![conf];
@@ -124,9 +163,20 @@ mod tests {
             config.background_path.as_deref(),
             Some("/custom/wallpaper.jpg")
         );
+        assert_eq!(config.background_blur, Some(20.0));
         assert_eq!(config.gtk_theme.as_deref(), Some("catppuccin"));
     }
 
+    #[test]
+    fn load_config_blur_optional() {
+        let dir = tempfile::tempdir().unwrap();
+        let conf = dir.path().join("moongreet.toml");
+        fs::write(&conf, "[appearance]\nbackground = \"/bg.jpg\"\n").unwrap();
+        let paths = vec![conf];
+        let config = load_config(Some(&paths));
+        assert!(config.background_blur.is_none());
+    }
+
     #[test]
     fn load_config_resolves_relative_background() {
         let dir = tempfile::tempdir().unwrap();
@@ -180,11 +230,11 @@ mod tests {
         fs::write(&wallpaper, "fake").unwrap();
         let config = Config {
             background_path: Some(wallpaper.to_str().unwrap().to_string()),
-            gtk_theme: None,
+            ..Config::default()
         };
         assert_eq!(
             resolve_background_path_with(&config, Path::new("/nonexistent")),
-            wallpaper
+            Some(wallpaper)
         );
     }
 
@@ -192,10 +242,10 @@ mod tests {
     fn resolve_ignores_config_path_when_file_missing() {
         let config = Config {
             background_path: Some("/nonexistent/wallpaper.jpg".to_string()),
-            gtk_theme: None,
+            ..Config::default()
         };
         let result = resolve_background_path_with(&config, Path::new("/nonexistent"));
-        assert!(result.to_str().unwrap().contains("moongreet"));
+        assert!(result.is_none());
     }
 
     #[test]
@@ -206,14 +256,31 @@ mod tests {
         let config = Config::default();
         assert_eq!(
             resolve_background_path_with(&config, &moonarch_wp),
-            moonarch_wp
+            Some(moonarch_wp)
         );
     }
 
     #[test]
-    fn resolve_uses_gresource_fallback_as_last_resort() {
+    fn resolve_returns_none_when_no_wallpaper_found() {
         let config = Config::default();
         let result = resolve_background_path_with(&config, Path::new("/nonexistent"));
-        assert!(result.to_str().unwrap().contains("wallpaper.jpg"));
+        assert!(result.is_none());
+    }
+
+    #[test]
+    fn load_config_fingerprint_enabled_default_true() {
+        let paths = vec![PathBuf::from("/nonexistent/moongreet.toml")];
+        let config = load_config(Some(&paths));
+        assert!(config.fingerprint_enabled);
+    }
+
+    #[test]
+    fn load_config_fingerprint_disabled() {
+        let dir = tempfile::tempdir().unwrap();
+        let conf = dir.path().join("moongreet.toml");
+        fs::write(&conf, "[appearance]\nfingerprint-enabled = false\n").unwrap();
+        let paths = vec![conf];
+        let config = load_config(Some(&paths));
+        assert!(!config.fingerprint_enabled);
     }
 }

src/fingerprint.rs

@@ -0,0 +1,137 @@
+// ABOUTME: fprintd D-Bus probe for fingerprint device availability.
+// ABOUTME: Checks if fprintd is running and the user has enrolled fingerprints.
+
+use gio::prelude::*;
+use gtk4::gio;
+
+const FPRINTD_BUS_NAME: &str = "net.reactivated.Fprint";
+const FPRINTD_MANAGER_PATH: &str = "/net/reactivated/Fprint/Manager";
+const FPRINTD_MANAGER_IFACE: &str = "net.reactivated.Fprint.Manager";
+const FPRINTD_DEVICE_IFACE: &str = "net.reactivated.Fprint.Device";
+
+const DBUS_TIMEOUT_MS: i32 = 3000;
+
+/// Lightweight fprintd probe — detects device availability and finger enrollment.
+/// Does NOT perform verification (that happens through greetd/PAM).
+pub struct FingerprintProbe {
+    device_proxy: Option<gio::DBusProxy>,
+}
+
+impl FingerprintProbe {
+    /// Create a probe without any D-Bus connections.
+    /// Call `init_async().await` to connect to fprintd.
+    pub fn new() -> Self {
+        FingerprintProbe {
+            device_proxy: None,
+        }
+    }
+
+    /// Connect to fprintd on the system bus and discover the default device.
+    pub async fn init_async(&mut self) {
+        let manager = match gio::DBusProxy::for_bus_future(
+            gio::BusType::System,
+            gio::DBusProxyFlags::NONE,
+            None,
+            FPRINTD_BUS_NAME,
+            FPRINTD_MANAGER_PATH,
+            FPRINTD_MANAGER_IFACE,
+        )
+        .await
+        {
+            Ok(m) => m,
+            Err(e) => {
+                log::debug!("fprintd manager not available: {e}");
+                return;
+            }
+        };
+
+        let result = match manager
+            .call_future("GetDefaultDevice", None, gio::DBusCallFlags::NONE, DBUS_TIMEOUT_MS)
+            .await
+        {
+            Ok(r) => r,
+            Err(e) => {
+                log::debug!("fprintd GetDefaultDevice failed: {e}");
+                return;
+            }
+        };
+
+        let device_path = match result.child_value(0).get::<String>() {
+            Some(p) => p,
+            None => {
+                log::debug!("fprintd: unexpected GetDefaultDevice response type");
+                return;
+            }
+        };
+        if device_path.is_empty() {
+            return;
+        }
+
+        match gio::DBusProxy::for_bus_future(
+            gio::BusType::System,
+            gio::DBusProxyFlags::NONE,
+            None,
+            FPRINTD_BUS_NAME,
+            &device_path,
+            FPRINTD_DEVICE_IFACE,
+        )
+        .await
+        {
+            Ok(proxy) => {
+                self.device_proxy = Some(proxy);
+            }
+            Err(e) => {
+                log::debug!("fprintd device proxy failed: {e}");
+            }
+        }
+    }
+
+    /// Check if the user has enrolled fingerprints on the default device.
+    /// Returns false if fprintd is unavailable or the user has no enrollments.
+    pub async fn is_available_async(&self, username: &str) -> bool {
+        let proxy = match &self.device_proxy {
+            Some(p) => p,
+            None => return false,
+        };
+
+        let args = glib::Variant::from((&username,));
+        match proxy
+            .call_future(
+                "ListEnrolledFingers",
+                Some(&args),
+                gio::DBusCallFlags::NONE,
+                DBUS_TIMEOUT_MS,
+            )
+            .await
+        {
+            Ok(result) => match result.child_value(0).get::<Vec<String>>() {
+                Some(fingers) => !fingers.is_empty(),
+                None => {
+                    log::debug!("fprintd: unexpected ListEnrolledFingers response type");
+                    false
+                }
+            },
+            Err(_) => false,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn new_probe_has_no_device() {
+        let probe = FingerprintProbe::new();
+        assert!(probe.device_proxy.is_none());
+    }
+
+    #[test]
+    fn constants_are_defined() {
+        assert!(!FPRINTD_BUS_NAME.is_empty());
+        assert!(!FPRINTD_MANAGER_PATH.is_empty());
+        assert!(!FPRINTD_MANAGER_IFACE.is_empty());
+        assert!(!FPRINTD_DEVICE_IFACE.is_empty());
+        assert!(DBUS_TIMEOUT_MS > 0);
+    }
+}

src/i18n.rs

@@ -23,13 +23,13 @@ pub struct Strings {
     pub greetd_sock_unreachable: &'static str,
     pub auth_failed: &'static str,
     pub wrong_password: &'static str,
-    pub multi_stage_unsupported: &'static str,
+    pub fingerprint_prompt: &'static str,
     pub invalid_session_command: &'static str,
     pub session_start_failed: &'static str,
     pub reboot_failed: &'static str,
     pub shutdown_failed: &'static str,
-    pub connection_error: &'static str,
     pub socket_error: &'static str,
+    pub unexpected_greetd_response: &'static str,
 
     // Templates (use .replace("{n}", &count.to_string()))
     pub faillock_attempts_remaining: &'static str,
@@ -47,13 +47,13 @@ const STRINGS_DE: Strings = Strings {
     greetd_sock_unreachable: "GREETD_SOCK nicht erreichbar",
     auth_failed: "Authentifizierung fehlgeschlagen",
     wrong_password: "Falsches Passwort",
-    multi_stage_unsupported: "Mehrstufige Authentifizierung wird nicht unterstützt",
+    fingerprint_prompt: "Fingerabdruck auflegen oder Passwort eingeben",
     invalid_session_command: "Ungültiger Session-Befehl",
     session_start_failed: "Session konnte nicht gestartet werden",
     reboot_failed: "Neustart fehlgeschlagen",
     shutdown_failed: "Herunterfahren fehlgeschlagen",
-    connection_error: "Verbindungsfehler",
     socket_error: "Socket-Fehler",
+    unexpected_greetd_response: "Unerwartete Antwort von greetd",
     faillock_attempts_remaining: "Noch {n} Versuch(e) vor Kontosperrung!",
     faillock_locked: "Konto ist möglicherweise gesperrt",
 };
@@ -69,13 +69,13 @@ const STRINGS_EN: Strings = Strings {
     greetd_sock_unreachable: "GREETD_SOCK unreachable",
     auth_failed: "Authentication failed",
     wrong_password: "Wrong password",
-    multi_stage_unsupported: "Multi-stage authentication is not supported",
+    fingerprint_prompt: "Place finger on reader or enter password",
     invalid_session_command: "Invalid session command",
     session_start_failed: "Failed to start session",
     reboot_failed: "Reboot failed",
     shutdown_failed: "Shutdown failed",
-    connection_error: "Connection error",
     socket_error: "Socket error",
+    unexpected_greetd_response: "Unexpected response from greetd",
     faillock_attempts_remaining: "{n} attempt(s) remaining before lockout!",
     faillock_locked: "Account may be locked",
 };
@@ -124,10 +124,15 @@ pub fn detect_locale() -> String {
         .filter(|s| !s.is_empty())
         .or_else(|| read_lang_from_conf(Path::new(DEFAULT_LOCALE_CONF)));
 
-    match lang {
-        Some(l) => parse_lang_prefix(&l),
+    let result = match lang {
+        Some(ref l) => parse_lang_prefix(l),
         None => "en".to_string(),
-    }
+    };
+    log::debug!("Detected locale: {result} (source: {})", match lang {
+        Some(_) => "LANG env or locale.conf",
+        None => "default",
+    });
+    result
 }
 
 /// Return the string table for the given locale, defaulting to English.
@@ -277,10 +282,12 @@ mod tests {
             assert!(!s.greetd_sock_not_set.is_empty(), "{locale}: greetd_sock_not_set");
             assert!(!s.auth_failed.is_empty(), "{locale}: auth_failed");
             assert!(!s.wrong_password.is_empty(), "{locale}: wrong_password");
+            assert!(!s.fingerprint_prompt.is_empty(), "{locale}: fingerprint_prompt");
             assert!(!s.reboot_failed.is_empty(), "{locale}: reboot_failed");
             assert!(!s.shutdown_failed.is_empty(), "{locale}: shutdown_failed");
             assert!(!s.faillock_attempts_remaining.is_empty(), "{locale}: faillock_attempts_remaining");
             assert!(!s.faillock_locked.is_empty(), "{locale}: faillock_locked");
+            assert!(!s.unexpected_greetd_response.is_empty(), "{locale}: unexpected_greetd_response");
         }
     }
 

src/ipc.rs

@@ -75,7 +75,6 @@ fn recv_payload(stream: &mut UnixStream, n: usize) -> Result<Vec<u8>, IpcError>
 }
 
 /// Send a length-prefixed JSON message to the greetd socket.
-/// Header and payload are sent in a single write for atomicity.
 pub fn send_message(
     stream: &mut UnixStream,
     msg: &serde_json::Value,
@@ -85,11 +84,12 @@ pub fn send_message(
         return Err(IpcError::PayloadTooLarge(payload.len()));
     }
 
+    let msg_type = msg.get("type").and_then(|v| v.as_str()).unwrap_or("unknown");
+    log::debug!("IPC send: type={msg_type}, size={} bytes", payload.len());
+
     let header = (payload.len() as u32).to_le_bytes();
-    let mut buf = Vec::with_capacity(4 + payload.len());
-    buf.extend_from_slice(&header);
-    buf.extend_from_slice(&payload);
-    stream.write_all(&buf)?;
+    stream.write_all(&header)?;
+    stream.write_all(&payload)?;
     Ok(())
 }
 
@@ -104,6 +104,8 @@ pub fn recv_message(stream: &mut UnixStream) -> Result<serde_json::Value, IpcErr
 
     let payload = recv_payload(stream, length)?;
     let value: serde_json::Value = serde_json::from_slice(&payload)?;
+    let msg_type = value.get("type").and_then(|v| v.as_str()).unwrap_or("unknown");
+    log::debug!("IPC recv: type={msg_type}, size={length} bytes");
     Ok(value)
 }
 

src/main.rs

@@ -2,6 +2,7 @@
 // ABOUTME: Sets up GTK Application, Layer Shell, CSS, and multi-monitor windows.
 
 mod config;
+mod fingerprint;
 mod greeter;
 mod i18n;
 mod ipc;
@@ -13,8 +14,6 @@ use gdk4 as gdk;
 use gtk4::prelude::*;
 use gtk4::{self as gtk, gio};
 use gtk4_layer_shell::LayerShell;
-use std::path::PathBuf;
-
 fn load_css(display: &gdk::Display) {
     let css_provider = gtk::CssProvider::new();
     css_provider.load_from_resource("/dev/moonarch/moongreet/style.css");
@@ -25,9 +24,9 @@ fn load_css(display: &gdk::Display) {
     );
 }
 
-fn setup_layer_shell(window: &gtk::ApplicationWindow, keyboard: bool) {
+fn setup_layer_shell(window: &gtk::ApplicationWindow, keyboard: bool, layer: gtk4_layer_shell::Layer) {
     window.init_layer_shell();
-    window.set_layer(gtk4_layer_shell::Layer::Top);
+    window.set_layer(layer);
     window.set_exclusive_zone(-1);
     if keyboard {
         window.set_keyboard_mode(gtk4_layer_shell::KeyboardMode::Exclusive);
@@ -48,31 +47,40 @@ fn activate(app: &gtk::Application) {
         }
     };
 
+    log::debug!("Display: {:?}", display);
     load_css(&display);
 
     // Load config and resolve wallpaper
     let config = config::load_config(None);
-    let bg_path = config::resolve_background_path(&config);
+    let bg_texture = config::resolve_background_path(&config)
+        .and_then(|path| {
+            log::debug!("Background path: {}", path.display());
+            greeter::load_background_texture(&path)
+        });
 
     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_path, &config, app);
+    let greeter_window = greeter::create_greeter_window(bg_texture.as_ref(), &config, app);
     if use_layer_shell {
-        setup_layer_shell(&greeter_window, true);
+        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 {
+    if use_layer_shell
+        && let Some(ref texture) = bg_texture
+    {
         let monitors = display.monitors();
+        log::debug!("Monitor count: {}", monitors.n_items());
         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(&bg_path, app);
-                setup_layer_shell(&wallpaper, false);
+                let wallpaper = greeter::create_wallpaper_window(texture, config.background_blur, app);
+                setup_layer_shell(&wallpaper, false, gtk4_layer_shell::Layer::Bottom);
                 wallpaper.set_monitor(Some(&monitor));
                 wallpaper.present();
             }
@@ -81,23 +89,22 @@ fn activate(app: &gtk::Application) {
 }
 
 fn setup_logging() {
-    let mut builder = env_logger::Builder::from_default_env();
-    builder.filter_level(log::LevelFilter::Info);
-
-    // Try file logging to /var/cache/moongreet/ — fall back to stderr
-    let log_dir = PathBuf::from("/var/cache/moongreet");
-    if log_dir.is_dir() {
-        let log_file = log_dir.join("moongreet.log");
-        if let Ok(file) = std::fs::OpenOptions::new()
-            .create(true)
-            .append(true)
-            .open(&log_file)
-        {
-            builder.target(env_logger::Target::Pipe(Box::new(file)));
+    match systemd_journal_logger::JournalLog::new() {
+        Ok(logger) => {
+            if let Err(e) = logger.install() {
+                eprintln!("Failed to install journal logger: {e}");
             }
         }
-
-    builder.init();
+        Err(e) => {
+            eprintln!("Failed to create journal logger: {e}");
+        }
+    }
+    let level = if std::env::var("MOONGREET_DEBUG").is_ok() {
+        log::LevelFilter::Debug
+    } else {
+        log::LevelFilter::Info
+    };
+    log::set_max_level(level);
 }
 
 fn main() {

src/power.rs

@@ -7,7 +7,6 @@ use std::process::Command;
 #[derive(Debug)]
 pub enum PowerError {
     CommandFailed { action: &'static str, message: String },
-    Timeout { action: &'static str },
 }
 
 impl fmt::Display for PowerError {
@@ -16,9 +15,6 @@ impl fmt::Display for PowerError {
             PowerError::CommandFailed { action, message } => {
                 write!(f, "{action} failed: {message}")
             }
-            PowerError::Timeout { action } => {
-                write!(f, "{action} timed out")
-            }
         }
     }
 }
@@ -27,6 +23,7 @@ impl std::error::Error for PowerError {}
 
 /// Run a command and return a PowerError on failure.
 fn run_command(action: &'static str, program: &str, args: &[&str]) -> Result<(), PowerError> {
+    log::debug!("Power action: {action} ({program} {args:?})");
     let child = Command::new(program)
         .args(args)
         .spawn()
@@ -42,7 +39,9 @@ fn run_command(action: &'static str, program: &str, args: &[&str]) -> Result<(),
             message: e.to_string(),
         })?;
 
-    if !output.status.success() {
+    if output.status.success() {
+        log::debug!("Power action {action} completed successfully");
+    } else {
         let stderr = String::from_utf8_lossy(&output.stderr);
         return Err(PowerError::CommandFailed {
             action,
@@ -76,12 +75,6 @@ mod tests {
         assert_eq!(err.to_string(), "reboot failed: No such file or directory");
     }
 
-    #[test]
-    fn power_error_timeout_display() {
-        let err = PowerError::Timeout { action: "shutdown" };
-        assert_eq!(err.to_string(), "shutdown timed out");
-    }
-
     #[test]
     fn run_command_returns_error_for_missing_binary() {
         let result = run_command("test", "nonexistent-binary-xyz", &[]);
@@ -106,7 +99,7 @@ mod tests {
 
     #[test]
     fn run_command_passes_args() {
-        let result = run_command("test", "echo", &["hello", "world"]);
+        let result = run_command("test", "true", &["--ignored-arg"]);
         assert!(result.is_ok());
     }
 }

src/sessions.rs

@@ -12,6 +12,7 @@ const DEFAULT_XSESSION_DIRS: &[&str] = &["/usr/share/xsessions"];
 pub struct Session {
     pub name: String,
     pub exec_cmd: String,
+    #[allow(dead_code)] // Retained for future Wayland-only filtering
     pub session_type: String,
 }
 
@@ -46,8 +47,17 @@ fn parse_desktop_file(path: &Path, session_type: &str) -> Option<Session> {
         }
     }
 
-    let name = name.filter(|s| !s.is_empty())?;
-    let exec_cmd = exec_cmd.filter(|s| !s.is_empty())?;
+    let name = name.filter(|s| !s.is_empty());
+    let exec_cmd = exec_cmd.filter(|s| !s.is_empty());
+
+    if name.is_none() || exec_cmd.is_none() {
+        log::debug!("Skipping {}: missing Name={} Exec={}", path.display(),
+            name.is_some(), exec_cmd.is_some());
+        return None;
+    }
+
+    let name = name?;
+    let exec_cmd = exec_cmd?;
 
     Some(Session {
         name,
@@ -74,7 +84,10 @@ pub fn get_sessions(
     for (dirs, session_type) in [(wayland, "wayland"), (xsession, "x11")] {
         for directory in dirs {
             let entries = match fs::read_dir(directory) {
-                Ok(e) => e,
+                Ok(e) => {
+                    log::debug!("Scanning session directory: {}", directory.display());
+                    e
+                }
                 Err(_) => continue,
             };
 
@@ -93,6 +106,7 @@ pub fn get_sessions(
         }
     }
 
+    log::debug!("Found {} session(s)", sessions.len());
     sessions
 }
 

src/users.rs

@@ -23,9 +23,11 @@ const NOLOGIN_SHELLS: &[&str] = &[
 #[derive(Debug, Clone)]
 pub struct User {
     pub username: String,
+    #[allow(dead_code)] // Retained for debugging and future UID-based features
     pub uid: u32,
     pub gecos: String,
     pub home: PathBuf,
+    #[allow(dead_code)] // Retained for debugging and future shell-based filtering
     pub shell: String,
 }
 
@@ -46,22 +48,22 @@ pub fn get_users(passwd_path: Option<&Path>) -> Vec<User> {
 
     let content = match fs::read_to_string(path) {
         Ok(c) => c,
-        Err(_) => return Vec::new(),
+        Err(e) => {
+            log::warn!("Failed to read passwd file {}: {e}", path.display());
+            return Vec::new();
+        }
     };
 
     let mut users = Vec::new();
 
     for line in content.lines() {
-        let parts: Vec<&str> = line.split(':').collect();
-        if parts.len() < 7 {
+        let mut fields = line.splitn(7, ':');
+        let (Some(username), Some(_pw), Some(uid_str), Some(_gid), Some(gecos), Some(home), Some(shell)) =
+            (fields.next(), fields.next(), fields.next(), fields.next(),
+             fields.next(), fields.next(), fields.next())
+        else {
             continue;
-        }
-
-        let username = parts[0];
-        let uid_str = parts[2];
-        let gecos = parts[4];
-        let home = parts[5];
-        let shell = parts[6];
+        };
 
         let uid = match uid_str.parse::<u32>() {
             Ok(u) => u,
@@ -88,6 +90,7 @@ pub fn get_users(passwd_path: Option<&Path>) -> Vec<User> {
         });
     }
 
+    log::debug!("Found {} login user(s)", users.len());
     users
 }
 
@@ -106,17 +109,28 @@ pub fn get_avatar_path_with(
     // AccountsService icon takes priority
     if accountsservice_dir.exists() {
         let icon = accountsservice_dir.join(username);
-        if icon.exists() && !icon.is_symlink() {
+        if let Ok(meta) = icon.symlink_metadata() {
+            if meta.file_type().is_symlink() {
+                log::warn!("Rejecting symlink avatar for {username}: {}", icon.display());
+            } else {
+                log::debug!("Avatar for {username}: AccountsService {}", icon.display());
                 return Some(icon);
             }
         }
+    }
 
     // ~/.face fallback
     let face = home.join(".face");
-    if face.exists() && !face.is_symlink() {
+    if let Ok(meta) = face.symlink_metadata() {
+        if meta.file_type().is_symlink() {
+            log::warn!("Rejecting symlink avatar for {username}: {}", face.display());
+        } else {
+            log::debug!("Avatar for {username}: ~/.face {}", face.display());
             return Some(face);
         }
+    }
 
+    log::debug!("No avatar found for {username}");
     None
 }