fix: GTK-Theme-Validierung entfernt — GTK löst Theme-Namen selbst auf

Die Regex VALID_THEME_NAME blockierte Theme-Namen mit '+' (z.B.
catppuccin-mocha-lavender-standard+default). Da GTK den Theme-Namen
intern über Standardverzeichnisse auflöst, ist eigene Validierung
unnötig und kontraproduktiv.

config/moongreet.toml

@@ -4,3 +4,5 @@
 [appearance]
 # Absolute path to wallpaper image
 background = "/usr/share/backgrounds/wallpaper.jpg"
+# GTK theme for the greeter UI
+gtk-theme = "catppuccin-mocha-lavender-standard+default"

pkg/PKGBUILD

@@ -4,7 +4,7 @@
 # Maintainer: Dominik Kressler
 
 pkgname=moongreet-git
-pkgver=0.1.0
+pkgver=0.1.0.r7.g357d245
 pkgrel=1
 pkgdesc="A greetd greeter for Wayland, built with Python + GTK4 + gtk4-layer-shell"
 arch=('any')
@@ -46,6 +46,7 @@ package() {
     # Greeter config
     install -Dm644 config/moongreet.toml "$pkgdir/etc/moongreet/moongreet.toml"
 
-    # Cache directory
+    # Cache directories
     install -dm755 "$pkgdir/var/cache/moongreet"
+    install -dm755 "$pkgdir/var/cache/moongreet/last-session"
 }

pkg/moongreet.install

@@ -4,6 +4,7 @@
 post_install() {
     if getent passwd greeter > /dev/null 2>&1; then
         chown greeter:greeter /var/cache/moongreet
+        chown greeter:greeter /var/cache/moongreet/last-session
     fi
 
     echo "==> Moongreet installed."

src/moongreet/config.py

@@ -17,6 +17,7 @@ class Config:
     """Greeter configuration loaded from moongreet.toml."""
 
     background: Path | None = None
+    gtk_theme: str | None = None
 
 
 def load_config(config_path: Path | None = None) -> Config:
@@ -51,6 +52,10 @@ def load_config(config_path: Path | None = None) -> Config:
             bg_path = config_path.parent / bg_path
         config.background = bg_path
 
+    gtk_theme = appearance.get("gtk-theme")
+    if gtk_theme:
+        config.gtk_theme = gtk_theme
+
     return config
 
 

src/moongreet/greeter.py

@@ -21,13 +21,14 @@ from gi.repository import Gtk, Gdk, GLib, GdkPixbuf
 from moongreet.config import load_config, resolve_wallpaper_path
 from moongreet.i18n import load_strings, Strings
 from moongreet.ipc import create_session, post_auth_response, start_session, cancel_session
-from moongreet.users import User, get_users, get_avatar_path, get_user_gtk_theme
+from moongreet.users import User, get_users, get_avatar_path
 from moongreet.sessions import Session, get_sessions
 from moongreet.power import reboot, shutdown
 
 logger = logging.getLogger(__name__)
 
 LAST_USER_PATH = Path("/var/cache/moongreet/last-user")
+LAST_SESSION_DIR = Path("/var/cache/moongreet/last-session")
 FAILLOCK_MAX_ATTEMPTS = 3
 VALID_USERNAME = re.compile(r"^[a-zA-Z0-9_.-]+$")
 MAX_USERNAME_LENGTH = 256
@@ -93,6 +94,7 @@ class GreeterWindow(Gtk.ApplicationWindow):
         self._failed_attempts: dict[str, int] = {}
         self._bg_path = bg_path
 
+        self._apply_global_theme()
         self._build_ui()
         self._setup_keyboard_navigation()
         # Defer initial user selection until the window is realized,
@@ -286,26 +288,23 @@ class GreeterWindow(Gtk.ApplicationWindow):
                 # which works in ZIP wheels too, no exists() check needed
                 self._set_default_avatar()
 
-        # Apply user's GTK theme if available
+        # Pre-select last used session for this user
-        self._apply_user_theme(user)
+        self._select_last_session(user)
 
         # Focus password entry
         self._password_entry.grab_focus()
 
-    def _apply_user_theme(self, user: User) -> None:
+    def _apply_global_theme(self) -> None:
-        """Load the user's preferred GTK theme from their settings.ini."""
+        """Apply the GTK theme from moongreet.toml configuration."""
-        gtk_config_dir = user.home / ".config" / "gtk-4.0"
+        theme_name = self._config.gtk_theme
-        theme_name = get_user_gtk_theme(config_dir=gtk_config_dir)
+        if not theme_name:
+            return
 
         settings = Gtk.Settings.get_default()
         if settings is None:
             return
 
-        current = settings.get_property("gtk-theme-name")
-        if theme_name and current != theme_name:
         settings.set_property("gtk-theme-name", theme_name)
-        elif not theme_name and current:
-            settings.reset_property("gtk-theme-name")
 
     def _get_foreground_color(self) -> str:
         """Get the current GTK theme foreground color as a hex string."""
@@ -445,9 +444,12 @@ class GreeterWindow(Gtk.ApplicationWindow):
             with self._greetd_sock_lock:
                 self._greetd_sock = sock
 
-            # Step 1: Create session
+            # Step 1: Create session — if a stale session exists, cancel it and retry
             response = create_session(sock, user.username)
 
+            if response.get("type") == "error":
+                cancel_session(sock)
+                response = create_session(sock, user.username)
                 if response.get("type") == "error":
                     GLib.idle_add(self._on_login_error, response, self._strings.auth_failed)
                     return
@@ -459,6 +461,7 @@ class GreeterWindow(Gtk.ApplicationWindow):
                 if response.get("type") == "error":
                     self._failed_attempts[user.username] = self._failed_attempts.get(user.username, 0) + 1
                     warning = faillock_warning(self._failed_attempts[user.username], self._strings)
+                    cancel_session(sock)
                     GLib.idle_add(self._on_login_auth_error, response, warning)
                     return
 
@@ -479,6 +482,7 @@ class GreeterWindow(Gtk.ApplicationWindow):
 
                 if response.get("type") == "success":
                     self._save_last_user(user.username)
+                    self._save_last_session(user.username, session.name)
                     self._close_greetd_sock()
                     GLib.idle_add(self.get_application().quit)
                     return
@@ -533,6 +537,18 @@ class GreeterWindow(Gtk.ApplicationWindow):
             return self._sessions[idx]
         return None
 
+    def _select_last_session(self, user: User) -> None:
+        """Pre-select the last used session for a user in the dropdown."""
+        if not self._sessions:
+            return
+        last_session_name = self._load_last_session(user.username)
+        if not last_session_name:
+            return
+        for i, session in enumerate(self._sessions):
+            if session.name == last_session_name:
+                self._session_dropdown.set_selected(i)
+                return
+
     MAX_GREETD_ERROR_LENGTH = 200
 
     def _show_greetd_error(self, response: dict, fallback: str) -> None:
@@ -585,3 +601,30 @@ class GreeterWindow(Gtk.ApplicationWindow):
             LAST_USER_PATH.write_text(username)
         except OSError:
             pass  # Non-critical — cache dir may not be writable
+
+    MAX_SESSION_NAME_LENGTH = 256
+
+    @staticmethod
+    def _save_last_session(username: str, session_name: str) -> None:
+        """Save the last used session name for a user to cache."""
+        if not VALID_USERNAME.match(username) or len(username) > MAX_USERNAME_LENGTH:
+            return
+        try:
+            LAST_SESSION_DIR.mkdir(parents=True, exist_ok=True)
+            (LAST_SESSION_DIR / username).write_text(session_name)
+        except OSError:
+            pass  # Non-critical — cache dir may not be writable
+
+    @staticmethod
+    def _load_last_session(username: str) -> str | None:
+        """Load the last used session name for a user from cache."""
+        session_file = LAST_SESSION_DIR / username
+        if not session_file.exists():
+            return None
+        try:
+            name = session_file.read_text().strip()
+        except OSError:
+            return None
+        if not name or len(name) > GreeterWindow.MAX_SESSION_NAME_LENGTH:
+            return None
+        return name

src/moongreet/ipc.py

@@ -22,14 +22,14 @@ def _recvall(sock: Any, n: int) -> bytes:
 def send_message(sock: Any, msg: dict) -> None:
     """Send a length-prefixed JSON message to the greetd socket."""
     payload = json.dumps(msg).encode("utf-8")
-    header = struct.pack("!I", len(payload))
+    header = struct.pack("=I", len(payload))
     sock.sendall(header + payload)
 
 
 def recv_message(sock: Any) -> dict:
     """Receive a length-prefixed JSON message from the greetd socket."""
     header = _recvall(sock, 4)
-    length = struct.unpack("!I", header)[0]
+    length = struct.unpack("=I", header)[0]
 
     if length > MAX_PAYLOAD_SIZE:
         raise ConnectionError(f"Payload too large: {length} bytes (max {MAX_PAYLOAD_SIZE})")

src/moongreet/users.py

@@ -2,12 +2,9 @@
 # ABOUTME: Provides User dataclass and helper functions for the greeter UI.
 
 import configparser
-import re
 from dataclasses import dataclass
 from pathlib import Path
 
-VALID_THEME_NAME = re.compile(r"^[A-Za-z0-9_-]+$")
-
 NOLOGIN_SHELLS = {"/usr/sbin/nologin", "/sbin/nologin", "/bin/false", "/usr/bin/nologin"}
 MIN_UID = 1000
 MAX_UID = 65533
@@ -106,8 +103,7 @@ def get_user_gtk_theme(config_dir: Path | None = None) -> str | None:
 
     if config.has_option("Settings", "gtk-theme-name"):
         theme = config.get("Settings", "gtk-theme-name")
-        # Validate against path traversal — only allow safe theme names
+        if theme:
-        if theme and VALID_THEME_NAME.match(theme):
             return theme
 
     return None

tests/test_config.py

@@ -43,6 +43,26 @@ class TestLoadConfig:
 
         assert config.background is None
 
+    def test_loads_gtk_theme(self, tmp_path: Path) -> None:
+        toml_file = tmp_path / "moongreet.toml"
+        toml_file.write_text(
+            "[appearance]\n"
+            'gtk-theme = "Catppuccin-Mocha-Standard-Blue-Dark"\n'
+        )
+
+        config = load_config(toml_file)
+
+        assert config.gtk_theme == "Catppuccin-Mocha-Standard-Blue-Dark"
+
+    def test_returns_none_gtk_theme_when_missing(self, tmp_path: Path) -> None:
+        toml_file = tmp_path / "moongreet.toml"
+        toml_file.write_text("[appearance]\n")
+
+        config = load_config(toml_file)
+
+        assert config.gtk_theme is None
+
+
     def test_resolves_relative_path_against_config_dir(self, tmp_path: Path) -> None:
         toml_file = tmp_path / "moongreet.toml"
         toml_file.write_text(

tests/test_integration.py

@@ -10,7 +10,7 @@ from pathlib import Path
 
 import pytest
 
-from moongreet.greeter import faillock_warning, FAILLOCK_MAX_ATTEMPTS
+from moongreet.greeter import faillock_warning, FAILLOCK_MAX_ATTEMPTS, LAST_SESSION_DIR
 from moongreet.i18n import load_strings
 from moongreet.ipc import create_session, post_auth_response, start_session, cancel_session
 
@@ -59,14 +59,14 @@ class MockGreetd:
                 header = self._recvall(conn, 4)
                 if len(header) < 4:
                     break
-                length = struct.unpack("!I", header)[0]
+                length = struct.unpack("=I", header)[0]
                 payload = self._recvall(conn, length)
                 msg = json.loads(payload.decode("utf-8"))
                 self._received.append(msg)
 
                 # Send response
                 resp_payload = json.dumps(response).encode("utf-8")
-                conn.sendall(struct.pack("!I", len(resp_payload)) + resp_payload)
+                conn.sendall(struct.pack("=I", len(resp_payload)) + resp_payload)
         finally:
             conn.close()
 
@@ -112,12 +112,13 @@ class TestLoginFlow:
         assert mock.received[1] == {"type": "post_auth_message_response", "response": "geheim"}
         assert mock.received[2] == {"type": "start_session", "cmd": ["Hyprland"]}
 
-    def test_wrong_password(self, tmp_path: Path) -> None:
+    def test_wrong_password_sends_cancel(self, tmp_path: Path) -> None:
-        """Simulate a failed login due to wrong password."""
+        """After a failed login, cancel_session must be sent to free the greetd session."""
         sock_path = tmp_path / "greetd.sock"
         mock = MockGreetd(sock_path)
         mock.expect({"type": "auth_message", "auth_message_type": "secret", "auth_message": "Password:"})
         mock.expect({"type": "error", "error_type": "auth_error", "description": "Authentication failed"})
+        mock.expect({"type": "success"})  # Response to cancel_session
         mock.start()
 
         try:
@@ -131,10 +132,64 @@ class TestLoginFlow:
             assert response["type"] == "error"
             assert response["description"] == "Authentication failed"
 
+            # The greeter must cancel the session after auth failure
+            response = cancel_session(sock)
+            assert response["type"] == "success"
+
             sock.close()
         finally:
             mock.stop()
 
+        assert mock.received[2] == {"type": "cancel_session"}
+
+    def test_stale_session_cancel_and_retry(self, tmp_path: Path) -> None:
+        """When create_session fails due to a stale session, cancel and retry."""
+        sock_path = tmp_path / "greetd.sock"
+        mock = MockGreetd(sock_path)
+        # First create_session → error (stale session)
+        mock.expect({"type": "error", "error_type": "error", "description": "a session is already being configured"})
+        # cancel_session → success
+        mock.expect({"type": "success"})
+        # Second create_session → auth_message (retry succeeds)
+        mock.expect({"type": "auth_message", "auth_message_type": "secret", "auth_message": "Password:"})
+        # post_auth_response → success
+        mock.expect({"type": "success"})
+        # start_session → success
+        mock.expect({"type": "success"})
+        mock.start()
+
+        try:
+            sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+            sock.connect(str(sock_path))
+
+            # Step 1: Create session fails
+            response = create_session(sock, "dominik")
+            assert response["type"] == "error"
+
+            # Step 2: Cancel stale session
+            response = cancel_session(sock)
+            assert response["type"] == "success"
+
+            # Step 3: Retry create session
+            response = create_session(sock, "dominik")
+            assert response["type"] == "auth_message"
+
+            # Step 4: Send password
+            response = post_auth_response(sock, "geheim")
+            assert response["type"] == "success"
+
+            # Step 5: Start session
+            response = start_session(sock, ["niri-session"])
+            assert response["type"] == "success"
+
+            sock.close()
+        finally:
+            mock.stop()
+
+        assert mock.received[0] == {"type": "create_session", "username": "dominik"}
+        assert mock.received[1] == {"type": "cancel_session"}
+        assert mock.received[2] == {"type": "create_session", "username": "dominik"}
+
     def test_multi_stage_auth_sends_cancel(self, tmp_path: Path) -> None:
         """When greetd sends a second auth_message after password, cancel the session."""
         sock_path = tmp_path / "greetd.sock"
@@ -264,3 +319,45 @@ class TestLastUser:
         from moongreet.greeter import GreeterWindow
         result = GreeterWindow._load_last_user()
         assert result is None
+
+
+class TestLastSession:
+    """Tests for saving and loading the last session per user."""
+
+    def test_save_and_load_last_session(self, tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+        monkeypatch.setattr("moongreet.greeter.LAST_SESSION_DIR", tmp_path)
+
+        from moongreet.greeter import GreeterWindow
+        GreeterWindow._save_last_session("dominik", "Niri")
+
+        session_file = tmp_path / "dominik"
+        assert session_file.exists()
+        assert session_file.read_text() == "Niri"
+
+        result = GreeterWindow._load_last_session("dominik")
+        assert result == "Niri"
+
+    def test_load_last_session_missing_file(self, tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+        monkeypatch.setattr("moongreet.greeter.LAST_SESSION_DIR", tmp_path)
+
+        from moongreet.greeter import GreeterWindow
+        result = GreeterWindow._load_last_session("nobody")
+        assert result is None
+
+    def test_load_last_session_rejects_oversized_name(self, tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+        monkeypatch.setattr("moongreet.greeter.LAST_SESSION_DIR", tmp_path)
+        (tmp_path / "dominik").write_text("A" * 300)
+
+        from moongreet.greeter import GreeterWindow
+        result = GreeterWindow._load_last_session("dominik")
+        assert result is None
+
+    def test_save_last_session_validates_username(self, tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+        """Usernames with path traversal should not create files outside the cache dir."""
+        monkeypatch.setattr("moongreet.greeter.LAST_SESSION_DIR", tmp_path)
+
+        from moongreet.greeter import GreeterWindow
+        GreeterWindow._save_last_session("../../etc/evil", "Niri")
+
+        # Should not have created any file
+        assert not (tmp_path / "../../etc/evil").exists()

tests/test_ipc.py

@@ -38,7 +38,7 @@ class FakeSocket:
     def with_response(cls, response: dict) -> "FakeSocket":
         """Create a FakeSocket pre-loaded with a length-prefixed JSON response."""
         payload = json.dumps(response).encode("utf-8")
-        data = struct.pack("!I", len(payload)) + payload
+        data = struct.pack("=I", len(payload)) + payload
         return cls(recv_data=data)
 
 
@@ -73,7 +73,7 @@ class TestSendMessage:
         send_message(sock, msg)
 
         payload = json.dumps(msg).encode("utf-8")
-        expected = struct.pack("!I", len(payload)) + payload
+        expected = struct.pack("=I", len(payload)) + payload
         assert bytes(sock.sent) == expected
 
     def test_sends_empty_dict(self) -> None:
@@ -82,7 +82,7 @@ class TestSendMessage:
         send_message(sock, {})
 
         payload = json.dumps({}).encode("utf-8")
-        expected = struct.pack("!I", len(payload)) + payload
+        expected = struct.pack("=I", len(payload)) + payload
         assert bytes(sock.sent) == expected
 
     def test_sends_nested_message(self) -> None:
@@ -93,7 +93,7 @@ class TestSendMessage:
 
         # Verify the payload is correctly length-prefixed
         length_bytes = bytes(sock.sent[:4])
-        length = struct.unpack("!I", length_bytes)[0]
+        length = struct.unpack("=I", length_bytes)[0]
         decoded = json.loads(sock.sent[4:])
         assert length == len(json.dumps(msg).encode("utf-8"))
         assert decoded == msg
@@ -132,7 +132,7 @@ class TestRecvMessage:
         """recv() may return fewer bytes than requested — must loop."""
         response = {"type": "success"}
         payload = json.dumps(response).encode("utf-8")
-        data = struct.pack("!I", len(payload)) + payload
+        data = struct.pack("=I", len(payload)) + payload
         sock = FragmentingSocket(data, chunk_size=3)
 
         result = recv_message(sock)
@@ -141,7 +141,7 @@ class TestRecvMessage:
 
     def test_rejects_oversized_payload(self) -> None:
         """Payloads exceeding the size limit must be rejected."""
-        header = struct.pack("!I", 10_000_000)
+        header = struct.pack("=I", 10_000_000)
         sock = FakeSocket(recv_data=header)
 
         with pytest.raises(ConnectionError, match="too large"):
@@ -162,7 +162,7 @@ class TestCreateSession:
         result = create_session(sock, "dominik")
 
         # Verify sent message
-        length = struct.unpack("!I", bytes(sock.sent[:4]))[0]
+        length = struct.unpack("=I", bytes(sock.sent[:4]))[0]
         sent_msg = json.loads(sock.sent[4 : 4 + length])
         assert sent_msg == {"type": "create_session", "username": "dominik"}
         assert result == response
@@ -177,7 +177,7 @@ class TestPostAuthResponse:
 
         result = post_auth_response(sock, "mypassword")
 
-        length = struct.unpack("!I", bytes(sock.sent[:4]))[0]
+        length = struct.unpack("=I", bytes(sock.sent[:4]))[0]
         sent_msg = json.loads(sock.sent[4 : 4 + length])
         assert sent_msg == {
             "type": "post_auth_message_response",
@@ -192,7 +192,7 @@ class TestPostAuthResponse:
 
         result = post_auth_response(sock, None)
 
-        length = struct.unpack("!I", bytes(sock.sent[:4]))[0]
+        length = struct.unpack("=I", bytes(sock.sent[:4]))[0]
         sent_msg = json.loads(sock.sent[4 : 4 + length])
         assert sent_msg == {
             "type": "post_auth_message_response",
@@ -209,7 +209,7 @@ class TestStartSession:
 
         result = start_session(sock, ["Hyprland"])
 
-        length = struct.unpack("!I", bytes(sock.sent[:4]))[0]
+        length = struct.unpack("=I", bytes(sock.sent[:4]))[0]
         sent_msg = json.loads(sock.sent[4 : 4 + length])
         assert sent_msg == {"type": "start_session", "cmd": ["Hyprland"]}
         assert result == response
@@ -220,7 +220,7 @@ class TestStartSession:
 
         result = start_session(sock, ["sway", "--config", "/etc/sway/config"])
 
-        length = struct.unpack("!I", bytes(sock.sent[:4]))[0]
+        length = struct.unpack("=I", bytes(sock.sent[:4]))[0]
         sent_msg = json.loads(sock.sent[4 : 4 + length])
         assert sent_msg == {
             "type": "start_session",
@@ -237,7 +237,7 @@ class TestCancelSession:
 
         result = cancel_session(sock)
 
-        length = struct.unpack("!I", bytes(sock.sent[:4]))[0]
+        length = struct.unpack("=I", bytes(sock.sent[:4]))[0]
         sent_msg = json.loads(sock.sent[4 : 4 + length])
         assert sent_msg == {"type": "cancel_session"}
         assert result == response

tests/test_users.py

@@ -186,27 +186,18 @@ class TestGetUserGtkTheme:
 
         assert result is None
 
-    def test_handles_interpolation_characters(self, tmp_path: Path) -> None:
+    def test_passes_theme_with_special_characters(self, tmp_path: Path) -> None:
-        """Theme names with % characters are rejected by validation."""
+        """Theme names with special characters are passed through to GTK."""
         gtk_dir = tmp_path / ".config" / "gtk-4.0"
         gtk_dir.mkdir(parents=True)
         settings = gtk_dir / "settings.ini"
-        settings.write_text("[Settings]\ngtk-theme-name=My%Theme\n")
+        settings.write_text(
+            "[Settings]\ngtk-theme-name=catppuccin-mocha-lavender-standard+default\n"
+        )
 
         result = get_user_gtk_theme(config_dir=gtk_dir)
 
-        assert result is None
+        assert result == "catppuccin-mocha-lavender-standard+default"
-
-    def test_rejects_path_traversal_theme_name(self, tmp_path: Path) -> None:
-        """Theme names with path traversal characters should be rejected."""
-        gtk_dir = tmp_path / ".config" / "gtk-4.0"
-        gtk_dir.mkdir(parents=True)
-        settings = gtk_dir / "settings.ini"
-        settings.write_text("[Settings]\ngtk-theme-name=../../../../etc/evil\n")
-
-        result = get_user_gtk_theme(config_dir=gtk_dir)
-
-        assert result is None
 
     def test_ignores_symlinked_accountsservice_icon(self, tmp_path: Path) -> None:
         """AccountsService icon as symlink should be ignored to prevent traversal."""