Cthulhu is no longer a fork. Now it is a screen reader written in Golang.

internal/sessionbus/sessionbus.go

@@ -0,0 +1,61 @@
+// Copyright (c) 2026 Storm Dragon
+// Authors: Storm Dragon, Angus Kola
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+// Package sessionbus selects the same desktop session bus as GLib clients,
+// including Python Cthulhu and I38lock, without changing the process environment.
+package sessionbus
+
+/*
+#cgo pkg-config: gio-2.0
+#include <gio/gio.h>
+*/
+import "C"
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"time"
+	"unsafe"
+
+	"github.com/godbus/dbus/v5"
+)
+
+func sessionAddress() (string, error) {
+	var nativeError *C.GError
+	address := C.g_dbus_address_get_for_bus_sync(C.G_BUS_TYPE_SESSION, nil, &nativeError)
+	if nativeError != nil {
+		defer C.g_error_free(nativeError)
+		return "", fmt.Errorf("resolve desktop session bus: %s", C.GoString(nativeError.message))
+	}
+	if address == nil {
+		return "", fmt.Errorf("resolve desktop session bus: no address")
+	}
+	defer C.g_free(C.gpointer(unsafe.Pointer(address)))
+	return C.GoString(address), nil
+}
+
+// Connect uses GLib's session address discovery and godbus's private connection.
+// Bus IDs let debug logs identify mismatched buses without exposing addresses.
+func Connect(logger *slog.Logger, component string) (*dbus.Conn, error) {
+	address, err := sessionAddress()
+	if err != nil {
+		return nil, err
+	}
+	connection, err := dbus.Connect(address)
+	if err != nil {
+		return nil, err
+	}
+	if logger != nil && logger.Enabled(context.Background(), slog.LevelDebug) {
+		ctx, cancel := context.WithTimeout(context.Background(), 500*time.Millisecond)
+		defer cancel()
+		var busID string
+		if err := connection.BusObject().CallWithContext(ctx, "org.freedesktop.DBus.GetId", 0).Store(&busID); err != nil {
+			logger.Debug("query session bus identity", "component", component, "error", err)
+		} else {
+			logger.Debug("connected to session bus", "component", component, "bus_id", busID)
+		}
+	}
+	return connection, nil
+}

internal/sessionbus/sessionbus_test.go

@@ -0,0 +1,107 @@
+// Copyright (c) 2026 Storm Dragon
+// Authors: Storm Dragon, Angus Kola
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package sessionbus
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"log/slog"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/godbus/dbus/v5"
+)
+
+func TestSessionBusHelper(t *testing.T) {
+	expectedID := os.Getenv("CTHULHU_SESSIONBUS_EXPECTED_ID")
+	if expectedID == "" {
+		t.Skip("subprocess helper")
+	}
+	before, present := os.LookupEnv("DBUS_SESSION_BUS_ADDRESS")
+	var output bytes.Buffer
+	logger := slog.New(slog.NewJSONHandler(&output, &slog.HandlerOptions{Level: slog.LevelDebug}))
+	connection, err := Connect(logger, "test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer connection.Close()
+	var busID string
+	if err := connection.BusObject().Call("org.freedesktop.DBus.GetId", 0).Store(&busID); err != nil {
+		t.Fatal(err)
+	}
+	if busID != expectedID {
+		t.Fatalf("selected bus %q, want %q", busID, expectedID)
+	}
+	if after, exists := os.LookupEnv("DBUS_SESSION_BUS_ADDRESS"); after != before || exists != present {
+		t.Fatal("session discovery changed process environment")
+	}
+	if !strings.Contains(output.String(), `"bus_id":"`+expectedID+`"`) {
+		t.Fatal("missing bus identity diagnostic")
+	}
+	if strings.Contains(output.String(), os.Getenv("XDG_RUNTIME_DIR")) {
+		t.Fatal("diagnostic exposes runtime directory")
+	}
+}
+
+func TestNativeDesktopSessionBusDiscovery(t *testing.T) {
+	if os.Getenv("CTHULHU_NATIVE_DBUS_TEST") != "1" {
+		t.Skip("requires private session bus sockets")
+	}
+	startBus := func() (string, string, string) {
+		runtimeDirectory := t.TempDir()
+		process := exec.Command("dbus-daemon", "--session", "--nofork", "--address=unix:path="+filepath.Join(runtimeDirectory, "bus"), "--print-address=1")
+		stdout, err := process.StdoutPipe()
+		if err != nil {
+			t.Fatal(err)
+		}
+		if err := process.Start(); err != nil {
+			t.Fatal(err)
+		}
+		t.Cleanup(func() { process.Process.Kill(); process.Wait() })
+		address, err := bufio.NewReader(stdout).ReadString('\n')
+		if err != nil {
+			t.Fatal(err)
+		}
+		connection, err := dbus.Connect(strings.TrimSpace(address))
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer connection.Close()
+		var busID string
+		if err := connection.BusObject().CallWithContext(context.Background(), "org.freedesktop.DBus.GetId", 0).Store(&busID); err != nil {
+			t.Fatal(err)
+		}
+		return runtimeDirectory, strings.TrimSpace(address), busID
+	}
+	runtimeDirectory, _, runtimeID := startBus()
+	_, explicitAddress, explicitID := startBus()
+	executable, err := os.Executable()
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, explicit := range []bool{false, true} {
+		expectedID := runtimeID
+		environment := make([]string, 0)
+		for _, value := range os.Environ() {
+			if !strings.HasPrefix(value, "DBUS_SESSION_BUS_ADDRESS=") && !strings.HasPrefix(value, "XDG_RUNTIME_DIR=") {
+				environment = append(environment, value)
+			}
+		}
+		if explicit {
+			environment = append(environment, "DBUS_SESSION_BUS_ADDRESS="+explicitAddress)
+			expectedID = explicitID
+		}
+		environment = append(environment, "XDG_RUNTIME_DIR="+runtimeDirectory, "CTHULHU_SESSIONBUS_EXPECTED_ID="+expectedID)
+		process := exec.Command(executable, "-test.run=^TestSessionBusHelper$", "-test.v")
+		process.Env = environment
+		if output, err := process.CombinedOutput(); err != nil {
+			t.Fatalf("explicit=%v: %v\n%s", explicit, err, output)
+		}
+	}
+}