Add a simple test to check Xwayland dying

The new test verifies that we handle Xwayland crashes gracefully.

autotests/integration/CMakeLists.txt

@@ -78,6 +78,7 @@ if (XCB_ICCCM_FOUND)
     integrationTest(NAME testSceneQPainterShadow SRCS scene_qpainter_shadow_test.cpp LIBS XCB::ICCCM)
     integrationTest(NAME testStackingOrder SRCS stacking_order_test.cpp LIBS XCB::ICCCM)
     integrationTest(NAME testDbusInterface SRCS dbus_interface_test.cpp LIBS XCB::ICCCM)
+    integrationTest(NAME testXwaylandServer SRCS xwaylandserver_test.cpp LIBS XCB::ICCCM)
 
     if (KWIN_BUILD_ACTIVITIES)
         integrationTest(NAME testActivities SRCS activities_test.cpp LIBS XCB::ICCCM)

autotests/integration/xwaylandserver_test.cpp

@@ -0,0 +1,139 @@
+/********************************************************************
+KWin - the KDE window manager
+This file is part of the KDE project.
+
+Copyright (C) 2020 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*********************************************************************/
+
+#include "kwin_wayland_test.h"
+#include "main.h"
+#include "platform.h"
+#include "screens.h"
+#include "unmanaged.h"
+#include "wayland_server.h"
+#include "workspace.h"
+#include "x11client.h"
+#include "xwl/xwayland_interface.h"
+
+#include <xcb/xcb_icccm.h>
+
+namespace KWin
+{
+
+struct XcbConnectionDeleter
+{
+    static inline void cleanup(xcb_connection_t *pointer)
+    {
+        xcb_disconnect(pointer);
+    }
+};
+
+static const QString s_socketName = QStringLiteral("wayland_test_kwin_xwayland_server-0");
+
+class XwaylandServerTest : public QObject
+{
+    Q_OBJECT
+
+private Q_SLOTS:
+    void initTestCase();
+    void testCrash();
+};
+
+void XwaylandServerTest::initTestCase()
+{
+    qRegisterMetaType<Unmanaged *>();
+    qRegisterMetaType<X11Client *>();
+    QSignalSpy applicationStartedSpy(kwinApp(), &Application::started);
+    QVERIFY(applicationStartedSpy.isValid());
+    kwinApp()->platform()->setInitialWindowSize(QSize(1280, 1024));
+    QVERIFY(waylandServer()->init(s_socketName.toLocal8Bit()));
+    QMetaObject::invokeMethod(kwinApp()->platform(), "setVirtualOutputs", Qt::DirectConnection, Q_ARG(int, 2));
+
+    kwinApp()->start();
+    QVERIFY(applicationStartedSpy.wait());
+    QCOMPARE(screens()->count(), 2);
+    QCOMPARE(screens()->geometry(0), QRect(0, 0, 1280, 1024));
+    QCOMPARE(screens()->geometry(1), QRect(1280, 0, 1280, 1024));
+    waylandServer()->initWorkspace();
+}
+
+void XwaylandServerTest::testCrash()
+{
+    // This test verifies that all connected X11 clients get destroyed when Xwayland crashes.
+
+    // Create a normal window.
+    QScopedPointer<xcb_connection_t, XcbConnectionDeleter> c(xcb_connect(nullptr, nullptr));
+    QVERIFY(!xcb_connection_has_error(c.data()));
+    const QRect windowGeometry(0, 0, 100, 200);
+    xcb_window_t window1 = xcb_generate_id(c.data());
+    xcb_create_window(c.data(), XCB_COPY_FROM_PARENT, window1, rootWindow(),
+                      windowGeometry.x(),
+                      windowGeometry.y(),
+                      windowGeometry.width(),
+                      windowGeometry.height(),
+                      0, XCB_WINDOW_CLASS_INPUT_OUTPUT, XCB_COPY_FROM_PARENT, 0, nullptr);
+    xcb_size_hints_t hints;
+    memset(&hints, 0, sizeof(hints));
+    xcb_icccm_size_hints_set_position(&hints, 1, windowGeometry.x(), windowGeometry.y());
+    xcb_icccm_size_hints_set_size(&hints, 1, windowGeometry.width(), windowGeometry.height());
+    xcb_icccm_size_hints_set_min_size(&hints, windowGeometry.width(), windowGeometry.height());
+    xcb_icccm_set_wm_normal_hints(c.data(), window1, &hints);
+    xcb_map_window(c.data(), window1);
+    xcb_flush(c.data());
+
+    QSignalSpy windowCreatedSpy(workspace(), &Workspace::clientAdded);
+    QVERIFY(windowCreatedSpy.isValid());
+    QVERIFY(windowCreatedSpy.wait());
+    QPointer<X11Client> client = windowCreatedSpy.last().first().value<X11Client *>();
+    QVERIFY(client);
+    QVERIFY(client->isDecorated());
+
+    // Create an override-redirect window.
+    xcb_window_t window2 = xcb_generate_id(c.data());
+    const uint32_t values[] = { true };
+    xcb_create_window(c.data(), XCB_COPY_FROM_PARENT, window2, rootWindow(),
+                      windowGeometry.x(), windowGeometry.y(),
+                      windowGeometry.width(), windowGeometry.height(), 0,
+                      XCB_WINDOW_CLASS_INPUT_OUTPUT, XCB_COPY_FROM_PARENT,
+                      XCB_CW_OVERRIDE_REDIRECT, values);
+    xcb_map_window(c.data(), window2);
+    xcb_flush(c.data());
+
+    QSignalSpy unmanagedAddedSpy(workspace(), &Workspace::unmanagedAdded);
+    QVERIFY(unmanagedAddedSpy.isValid());
+    QVERIFY(unmanagedAddedSpy.wait());
+    QPointer<Unmanaged> unmanaged = unmanagedAddedSpy.last().first().value<Unmanaged *>();
+    QVERIFY(unmanaged);
+
+    // Let's pretend that the Xwayland process has crashed.
+    QSignalSpy x11ConnectionChangedSpy(kwinApp(), &Application::x11ConnectionChanged);
+    QVERIFY(x11ConnectionChangedSpy.isValid());
+    xwayland()->process()->terminate();
+    QVERIFY(x11ConnectionChangedSpy.wait());
+
+    // When Xwayland crashes, the compositor should tear down the XCB connection and destroy
+    // all connected X11 clients.
+    QTRY_VERIFY(!client);
+    QTRY_VERIFY(!unmanaged);
+    QCOMPARE(kwinApp()->x11Connection(), nullptr);
+    QCOMPARE(kwinApp()->x11RootWindow(), XCB_WINDOW_NONE);
+    QCOMPARE(kwinApp()->x11ScreenNumber(), -1);
+}
+
+} // namespace KWin
+
+WAYLANDTEST_MAIN(KWin::XwaylandServerTest)
+#include "xwaylandserver_test.moc"

unmanaged.h

@@ -28,8 +28,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 namespace KWin
 {
 
-class Unmanaged
-    : public Toplevel
+class KWIN_EXPORT Unmanaged : public Toplevel
 {
     Q_OBJECT
 public:

xwl/xwayland.cpp

@@ -101,6 +101,11 @@ Xwayland::~Xwayland()
     s_self = nullptr;
 }
 
+QProcess *Xwayland::process() const
+{
+    return m_xwaylandProcess;
+}
+
 void Xwayland::init()
 {
     int pipeFds[2];

xwl/xwayland.h

@@ -24,8 +24,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #include <xcb/xproto.h>
 
-class QProcess;
-
 class xcb_screen_t;
 
 namespace KWin
@@ -56,6 +54,8 @@ public:
         return m_xfixes;
     }
 
+    QProcess *process() const override;
+
 Q_SIGNALS:
     void initialized();
     void criticalError(int code);

xwl/xwayland_interface.h

@@ -25,6 +25,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <QObject>
 #include <QPoint>
 
+class QProcess;
+
 namespace KWin
 {
 class Toplevel;
@@ -49,6 +51,7 @@ public:
     static XwaylandInterface *self();
 
     virtual Xwl::DragEventReply dragMoveFilter(Toplevel *target, const QPoint &pos) = 0;
+    virtual QProcess *process() const = 0;
 
 protected:
     explicit XwaylandInterface(QObject *parent = nullptr);