A11y: query a11y bus address from X display

Attempt to get the accessibility bus address from the X display, to
match libatspi's behavior. This allows the accessibility bus to be
found when an application is running as root.

[ChangeLog][QtGui] Linux accessibility (using XCB) will now works for
applications launched as root

Done-with: Mike Gorse
Change-Id: I49a263571b328cbd1fd90cb7f5cb40919d2a4951
Task-number: QTBUG-43674
Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>
Reviewed-by: Jørgen Lind <jorgen.lind@theqtcompany.com>

2 files changed, 27 insertions, 0 deletions

diff --git a/src/platformsupport/linuxaccessibility/dbusconnection.cpp b/src/platformsupport/linuxaccessibility/dbusconnection.cpp
index 45729fa065..637b06549a 100644
--- a/src/platformsupport/linuxaccessibility/dbusconnection.cpp
+++ b/src/platformsupport/linuxaccessibility/dbusconnection.cpp
@@ -42,6 +42,9 @@
 #include <QDBusConnectionInterface>
 #include "bus_interface.h"
 
+#include <QtGui/qguiapplication.h>
+#include <qplatformnativeinterface.h>
+
 QT_BEGIN_NAMESPACE
 
 QString A11Y_SERVICE = QStringLiteral("org.a11y.Bus");
@@ -65,6 +68,29 @@ DBusConnection::DBusConnection(QObject *parent)
     // If it is registered already, setup a11y right away
     if (c.interface()->isServiceRegistered(A11Y_SERVICE))
         serviceRegistered();
+
+    // In addition try if there is an xatom exposing the bus address, this allows applications run as root to work
+    QString address = getAddressFromXCB();
+    if (!address.isEmpty()) {
+        m_enabled = true;
+        connectA11yBus(address);
+    }
+}
+
+QString DBusConnection::getAddressFromXCB()
+{
+    QGuiApplication *app = qobject_cast<QGuiApplication *>(QCoreApplication::instance());
+    if (!app)
+        return QString();
+    QPlatformNativeInterface *platformNativeInterface = app->platformNativeInterface();
+    QByteArray *addressByteArray = reinterpret_cast<QByteArray*>(
+                platformNativeInterface->nativeResourceForIntegration(QByteArrayLiteral("AtspiBus")));
+    if (addressByteArray) {
+        QString address = QString::fromLatin1(*addressByteArray);
+        delete addressByteArray;
+        return address;
+    }
+    return QString();
 }
 
 // We have the a11y registry on the session bus.
diff --git a/src/platformsupport/linuxaccessibility/dbusconnection_p.h b/src/platformsupport/linuxaccessibility/dbusconnection_p.h
index a0bd6450bf..30707a3f95 100644
--- a/src/platformsupport/linuxaccessibility/dbusconnection_p.h
+++ b/src/platformsupport/linuxaccessibility/dbusconnection_p.h
@@ -68,6 +68,7 @@ Q_SIGNALS:
     void enabledChanged(bool enabled);
 
 private Q_SLOTS:
+    QString getAddressFromXCB();
     void serviceRegistered();
     void serviceUnregistered();
     void connectA11yBus(const QString &address);