Fingerprint login refactor

src/Cards/UserCard.vala

@@ -9,7 +9,7 @@ public class Greeter.UserCard : Greeter.BaseCard {
     public LightDM.User lightdm_user { get; construct; }
     public bool show_input { get; set; default = false; }
     public bool is_24h { get; set; default = true; }
-    // TODO: In Gtk4 remove this gesture and move it to MainWindow 
+    // TODO: In Gtk4 remove this gesture and move it to MainWindow
     public Gtk.GestureMultiPress click_gesture { get; private set; }
 
     private Pantheon.AccountsService greeter_act;
@@ -23,8 +23,14 @@ public class Greeter.UserCard : Greeter.BaseCard {
 
     private SelectionCheck logged_in;
 
-    public UserCard (LightDM.User lightdm_user) {
-        Object (lightdm_user: lightdm_user);
+    public FPrintUtil fprint_util { get; construct; }
+    public signal void do_fprint_login (string username);
+
+    public UserCard (LightDM.User lightdm_user, FPrintUtil fprint_util) {
+        Object (
+            lightdm_user: lightdm_user,
+            fprint_util: fprint_util
+        );
     }
 
     construct {
@@ -160,6 +166,12 @@ public class Greeter.UserCard : Greeter.BaseCard {
         password_entry.activate.connect (on_login);
         login_button.clicked.connect (on_login);
 
+        fprint_util.verify_passed.connect (() => {
+            do_fprint_login (lightdm_user.name);
+        });
+
+        fprint_util.verify_failed.connect (wrong_credentials);
+
         grab_focus.connect (password_entry.grab_focus_without_selecting);
     }
 
@@ -319,7 +331,7 @@ public class Greeter.UserCard : Greeter.BaseCard {
         settings.set_value ("xkb-options", options);
     }
 
-    /* 
+    /*
      * When we get string typed settings from our settings daemon account service we might get a null value.
      * In this case we reset the value to avoid criticals and unwanted behaviour.
      */
@@ -426,6 +438,12 @@ public class Greeter.UserCard : Greeter.BaseCard {
         SettingsPortal.get_default ().prefers_color_scheme = greeter_act.prefers_color_scheme;
     }
 
+    public override bool focus (Gtk.DirectionType direction) {
+        use_fingerprint = false;
+        fprint_util.stop ();
+        return base.focus (direction);
+    }
+
     public override void wrong_credentials () {
         password_entry.get_style_context ().add_class (Gtk.STYLE_CLASS_ERROR);
         main_box.get_style_context ().add_class ("shake");

src/FPrintUtils.vala

@@ -5,96 +5,106 @@
  * Authors: Corentin Noël <corentin@elementary.io>
  */
 
-namespace Greeter.FPrintUtils {
-    public enum MessageText {
-        FPRINT_SWIPE,
-        FPRINT_SWIPE_AGAIN,
-        FPRINT_SWIPE_TOO_SHORT,
-        FPRINT_NOT_CENTERED,
-        FPRINT_REMOVE,
-        FPRINT_PLACE,
-        FPRINT_PLACE_AGAIN,
-        FPRINT_NO_MATCH,
-        FPRINT_TIMEOUT,
-        FPRINT_ERROR,
-        FAILED,
-        OTHER
-    }
+[DBus (name = "net.reactivated.Fprint.Manager")]
+public interface FPrintManager : GLib.Object {
+    public abstract ObjectPath get_default_device () throws GLib.Error;
+    public abstract ObjectPath[] get_devices () throws GLib.Error;
+}
 
-    private inline string fprintd_message (string message) {
-        // TODO: Translate message using GLib.dgettext
-        return message;
-    }
+[DBus (name = "net.reactivated.Fprint.Device")]
+public interface FPrintDevice : GLib.Object {
+    public abstract string name { owned get; }
+    public abstract void claim (string username) throws GLib.Error;
+    public abstract void release () throws GLib.Error;
+    public abstract void verify_start (string finger) throws GLib.Error;
+    public abstract void verify_stop () throws GLib.Error;
+    public signal void verify_status (string result, bool done);
+}
+
+public class FPrintUtil : GLib.Object {
+    private FPrintManager manager;
+    private FPrintDevice[] devices = {};
 
-    public MessageText string_to_messagetext (string text) {
-        // Ideally this would query PAM and ask which module is currently active,
-        // but since we're running through LightDM we don't have that ability.
-        // There should at be a state machine to transition to and from the 
-        // active module depending on the messages received. But, this is can go
-        // wrong quickly. 
-        // The reason why this is needed is, for example, we can get the "An
-        // unknown error occurred" message from pam_fprintd, but we can get it 
-        // from some other random module as well. You never know.
-        // Maybe it's worth adding some LightDM/PAM functionality for this? 
-        // The PAM "feature" which makes it all tricky is that modules can send 
-        // arbitrary messages to the stream and it's hard to analyze or keep track
-        // of them programmatically. 
-        // Also, there doesn't seem to be a way to give the user a choice over
-        // which module he wants to use to authenticate (ie. maybe today I have
-        // a bandaid over my finger and I can't scan it so I have to wait for it
-        // time out, if I didn't disable that in the settings)
-        // 
-        // These messages are taken from here: 
-        //  - https://gitlab.freedesktop.org/libfprint/fprintd/blob/master/pam/fingerprint-strings.h
-        //  - https://gitlab.freedesktop.org/libfprint/fprintd/blob/master/pam/pam_fprintd.c
+    public signal void verify_passed ();
+    public signal void verify_failed ();
 
-        if (text == fprintd_message ("An unknown error occurred")) {
-            return MessageText.FPRINT_ERROR;
-        } else if (text == fprintd_message ("An unknown error occurred")) {
-            return MessageText.FPRINT_ERROR;
-        } else if (check_fprintd_string (text, "Swipe", "across")) {
-            return MessageText.FPRINT_SWIPE;
-        } else if (text == fprintd_message ("Swipe your finger again")) {
-            return MessageText.FPRINT_SWIPE_AGAIN;
-        } else if (text == fprintd_message ("Swipe was too short, try again")) {
-            return MessageText.FPRINT_SWIPE_TOO_SHORT;
-        } else if (text == fprintd_message ("Your finger was not centered, try swiping your finger again")) {
-            return MessageText.FPRINT_NOT_CENTERED;
-        } else if (text == fprintd_message ("Remove your finger, and try swiping your finger again")) {
-            return MessageText.FPRINT_REMOVE;
-        } else if (check_fprintd_string (text, "Place", "on")) {
-            return MessageText.FPRINT_PLACE;
-        } else if (text == fprintd_message ("Place your finger on the reader again")) {
-            return MessageText.FPRINT_PLACE_AGAIN;
-        } else if (text == fprintd_message ("Failed to match fingerprint")) {
-            return MessageText.FPRINT_NO_MATCH;
-        } else if (text == fprintd_message ("Verification timed out")) {
-            return MessageText.FPRINT_TIMEOUT;
-        } else if (text == "Login failed") {
-            return MessageText.FAILED;
+    public bool start (string username) {
+
+        bool any_started = false;
+
+        try {
+            manager = Bus.get_proxy_sync (
+                BusType.SYSTEM,
+                "net.reactivated.Fprint",
+                "/net/reactivated/Fprint/Manager",
+                DBusProxyFlags.NONE
+            );
+        } catch (Error e) {
+            debug (e.message);
+            return false;
         }
 
-        return MessageText.OTHER;
-    }
+        ObjectPath[]? device_paths = null;
 
-    private bool check_fprintd_string (string text, string action, string position) {
-        const string[] FINGERS = {
-            "finger",
-            "left thumb", "left index finger", "left middle finger", "left ring finger", "left little finger",
-            "right thumb", "right index finger", "right middle finger", "right ring finger", "right little finger"
-        };
+        try {
+            device_paths = manager.get_devices ();
+        } catch (Error e) {
+            debug (e.message);
+            return false;
+        }
 
-        foreach (unowned string finger in FINGERS) {
-            // Place your finger on %s
-            var english_string = action.concat (" your ", finger, " ", position, " %s");
+        foreach (var device_path in device_paths) {
+            FPrintDevice device;
+            try {
+                device = GLib.Bus.get_proxy_sync (
+                    GLib.BusType.SYSTEM,
+                    "net.reactivated.Fprint",
+                    device_path
+                );
+            } catch (Error e) {
+                debug (e.message);
+                continue;
+            }
+            devices += device;
+        }
 
-            if (text.has_prefix (fprintd_message (english_string)) ||
-                text.has_prefix (fprintd_message (english_string.printf ("the fingerprint reader")))) {
-                return true;
+        foreach (var device in devices) {
+            try {
+                device.claim (username);
+                device.verify_status.connect(status);
+                device.verify_start ("any");
+                any_started = true;
+            } catch (Error e) {
+                debug ("%s: %s", e.message, device.name);
             }
+        }
+
+        return any_started;
+    }
 
+    public void stop () {
+        foreach (var device in devices) {
+            try {
+                device.release ();
+            } catch (Error e) {
+                debug ("%s: %s", e.message, device.name);
+            }
         }
+    }
 
-        return false;
+    private void status (string result, bool done) {
+        if (result == "verify-match") {
+            foreach (var device in devices) {
+                try {
+                    device.verify_stop ();
+                } catch (GLib.Error e) {
+                    debug ("%s: %s", device.name, e.message);
+                }
+            }
+            stop ();
+            verify_passed ();
+        } else {
+            verify_failed ();
+        }
     }
 }

src/MainWindow.vala

@@ -21,6 +21,8 @@ public class Greeter.MainWindow : Gtk.ApplicationWindow {
     private int current_user_card_index = -1;
     private unowned Greeter.BaseCard? current_card = null;
 
+    private FPrintUtil fprint_util;
+
     private bool installer_mode = false;
 
     private Gtk.EventControllerKey key_controller;
@@ -37,10 +39,11 @@ public class Greeter.MainWindow : Gtk.ApplicationWindow {
         gsettings = new GLib.Settings ("io.elementary.greeter");
         settings = new Greeter.Settings ();
 
-        lightdm_greeter.show_message.connect (show_message);
         lightdm_greeter.show_prompt.connect (show_prompt);
         lightdm_greeter.authentication_complete.connect (authentication_complete);
 
+        fprint_util = new FPrintUtil ();
+
         var guest_login_button = new Gtk.Button.with_label (_("Log in as Guest"));
         var manual_login_button = new Gtk.ToggleButton.with_label (_("Manual Login…"));
 
@@ -264,20 +267,6 @@ public class Greeter.MainWindow : Gtk.ApplicationWindow {
         }
     }
 
-    private void show_message (string text, LightDM.MessageType type) {
-        var messagetext = Greeter.FPrintUtils.string_to_messagetext (text);
-        switch (messagetext) {
-            case Greeter.FPrintUtils.MessageText.FPRINT_TIMEOUT:
-            case Greeter.FPrintUtils.MessageText.FPRINT_ERROR:
-            case Greeter.FPrintUtils.MessageText.OTHER:
-                current_card.use_fingerprint = false;
-                break;
-            default:
-                current_card.use_fingerprint = true;
-                break;
-        }
-    }
-
     private void show_prompt (string text, LightDM.PromptType type = LightDM.PromptType.QUESTION) {
         if (current_card is ManualCard) {
             if (type == LightDM.PromptType.SECRET) {
@@ -362,6 +351,7 @@ public class Greeter.MainWindow : Gtk.ApplicationWindow {
             user_cards.head.foreach ((card) => {
                 if (card.lightdm_user.name == user_to_select) {
                     carousel.scroll_to (card);
+                    card.use_fingerprint = fprint_util.start (card.lightdm_user.name);
                     user_selected = true;
                 }
             });
@@ -370,6 +360,7 @@ public class Greeter.MainWindow : Gtk.ApplicationWindow {
                 unowned var user_card = user_cards.peek_head ();
                 user_card.show_input = true;
                 carousel.scroll_to (user_card);
+                user_card.use_fingerprint = fprint_util.start (user_card.lightdm_user.name);
             }
         } else {
             datetime_revealer.reveal_child = false;
@@ -400,9 +391,10 @@ public class Greeter.MainWindow : Gtk.ApplicationWindow {
     }
 
     private void add_card (LightDM.User lightdm_user) {
-        var user_card = new Greeter.UserCard (lightdm_user);
+        var user_card = new Greeter.UserCard (lightdm_user, fprint_util);
         user_card.show_all ();
         user_card.do_connect.connect (do_connect);
+        user_card.do_fprint_login.connect (do_connect_username);
         user_card.click_gesture.pressed.connect ((gesture, n_press, x, y) => {
             assert (gesture.widget is UserCard);
 
@@ -512,6 +504,7 @@ public class Greeter.MainWindow : Gtk.ApplicationWindow {
         unowned Greeter.UserCard? next_card = user_cards.peek_nth (current_user_card_index - 1);
         if (next_card != null) {
             carousel.scroll_to (next_card);
+            next_card.use_fingerprint = fprint_util.start (next_card.lightdm_user.name);
         }
     }
 
@@ -523,6 +516,7 @@ public class Greeter.MainWindow : Gtk.ApplicationWindow {
         unowned Greeter.UserCard? next_card = user_cards.peek_nth (current_user_card_index + 1);
         if (next_card != null) {
             carousel.scroll_to (next_card);
+            next_card.use_fingerprint = fprint_util.start (next_card.lightdm_user.name);
         }
     }
 }