KillWindow support for Wayland windows

Summary:
AbstractClient gains a new pure virtual killWindow method and this gets
implemented in ShellClient.

ShellClient performs the killing by sending a term signal to the
process. This can only work if the client connected through the socket
and didn't get a socketpair fd passed. In that case the pid is KWin's
and KWin doesn't want to terminate. Thus this is special handled to
destroy the connection instead.

In case terminating the process has no effect, the connection gets
destroyed after five seconds.

The KillWindow is adjusted to operate on AbstractClient instead of
Client.

This implements T4463.

Test Plan: Killed windows and auto test

Reviewers: #kwin, #plasma_on_wayland

Subscribers: plasma-devel, kwin

Tags: #plasma_on_wayland, #kwin

Differential Revision: https://phabricator.kde.org/D3370

abstract_client.h

@@ -614,6 +614,13 @@ public:
         return m_desktopFileName;
     }
 
+    /**
+     * Tries to terminate the process of this AbstractClient.
+     *
+     * Implementing subclasses can perform a windowing system solution for terminating.
+     **/
+    virtual void killWindow() = 0;
+
     // TODO: remove boolean trap
     static bool belongToSameApplication(const AbstractClient* c1, const AbstractClient* c2, bool active_hack = false);
 

autotests/integration/helper/CMakeLists.txt

@@ -5,3 +5,7 @@ ecm_mark_as_test(copy)
 add_executable(paste paste.cpp)
 target_link_libraries(paste Qt5::Gui)
 ecm_mark_as_test(paste)
+######################
+add_executable(kill kill.cpp)
+target_link_libraries(kill Qt5::Widgets)
+ecm_mark_as_test(kill)

autotests/integration/helper/kill.cpp

@@ -0,0 +1,32 @@
+/********************************************************************
+KWin - the KDE window manager
+This file is part of the KDE project.
+
+Copyright (C) 2016 Martin Gräßlin <mgraesslin@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 <QApplication>
+#include <QWidget>
+
+int main(int argc, char *argv[])
+{
+    qputenv("QT_QPA_PLATFORM", QByteArrayLiteral("wayland"));
+    QApplication app(argc, argv);
+    QWidget w;
+    w.setGeometry(QRect(0, 0, 100, 200));
+    w.show();
+
+    return app.exec();
+}

autotests/integration/shell_client_test.cpp

@@ -33,8 +33,15 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <KWayland/Client/surface.h>
 #include <KWayland/Client/xdgshell.h>
 
+#include <KWayland/Server/clientconnection.h>
+#include <KWayland/Server/display.h>
 #include <KWayland/Server/shell_interface.h>
 
+// system
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
 using namespace KWin;
 using namespace KWayland::Client;
 
@@ -64,6 +71,8 @@ private Q_SLOTS:
     void testHidden();
     void testDesktopFileName();
     void testCaptionSimplified();
+    void testKillWindow_data();
+    void testKillWindow();
 };
 
 void TestShellClient::initTestCase()
@@ -633,5 +642,53 @@ void TestShellClient::testCaptionSimplified()
     QCOMPARE(c->caption(), origTitle.simplified());
 }
 
+void TestShellClient::testKillWindow_data()
+{
+    QTest::addColumn<bool>("socketMode");
+
+    QTest::newRow("display") << false;
+    QTest::newRow("socket") << true;
+}
+
+void TestShellClient::testKillWindow()
+{
+    // this test verifies that killWindow properly terminates a process
+    // for this an external binary is launched
+    const QString kill = QFINDTESTDATA(QStringLiteral("helper/kill"));
+    QVERIFY(!kill.isEmpty());
+    QSignalSpy shellClientAddedSpy(waylandServer(), &WaylandServer::shellClientAdded);
+    QVERIFY(shellClientAddedSpy.isValid());
+
+    QScopedPointer<QProcess> process(new QProcess);
+    QProcessEnvironment env = QProcessEnvironment::systemEnvironment();
+    QFETCH(bool, socketMode);
+    if (socketMode) {
+        int sx[2];
+        QVERIFY(socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, sx) >= 0);
+        waylandServer()->display()->createClient(sx[0]);
+        int socket = dup(sx[1]);
+        QVERIFY(socket != -1);
+        env.insert(QStringLiteral("WAYLAND_SOCKET"), QByteArray::number(socket));
+        env.remove("WAYLAND_DISPLAY");
+    } else {
+        env.insert("WAYLAND_DISPLAY", s_socketName);
+    }
+    process->setProcessEnvironment(env);
+    process->setProcessChannelMode(QProcess::ForwardedChannels);
+    process->setProgram(kill);
+    process->start();
+    QVERIFY(process->waitForStarted());
+
+    AbstractClient *killClient = nullptr;
+    QVERIFY(shellClientAddedSpy.wait());
+    killClient = shellClientAddedSpy.first().first().value<AbstractClient*>();
+    QVERIFY(killClient);
+    QSignalSpy finishedSpy(process.data(), static_cast<void(QProcess::*)(int,QProcess::ExitStatus)>(&QProcess::finished));
+    QVERIFY(finishedSpy.isValid());
+    killClient->killWindow();
+    QVERIFY(finishedSpy.wait());
+    QVERIFY(!finishedSpy.isEmpty());
+}
+
 WAYLANDTEST_MAIN(TestShellClient)
 #include "shell_client_test.moc"

client.h

@@ -249,7 +249,7 @@ public:
     static bool belongToSameApplication(const Client* c1, const Client* c2, bool active_hack = false);
     static bool sameAppWindowRoleMatch(const Client* c1, const Client* c2, bool active_hack);
 
-    void killWindow();
+    void killWindow() override;
     void toggleShade();
     void showContextHelp() override;
     void cancelShadeHoverTimer();

killwindow.cpp

@@ -20,7 +20,7 @@ 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 "killwindow.h"
-#include "client.h"
+#include "abstract_client.h"
 #include "main.h"
 #include "platform.h"
 #include "unmanaged.h"
@@ -43,7 +43,7 @@ void KillWindow::start()
             if (!t) {
                 return;
             }
-            if (Client *c = qobject_cast<Client*>(t)) {
+            if (AbstractClient *c = qobject_cast<AbstractClient*>(t)) {
                 c->killWindow();
             } else if (Unmanaged *u = qobject_cast<Unmanaged*>(t)) {
                 xcb_kill_client(connection(), u->window());

shell_client.cpp

@@ -34,6 +34,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <KDecoration2/DecoratedClient>
 
 #include <KWayland/Client/surface.h>
+#include <KWayland/Server/clientconnection.h>
 #include <KWayland/Server/seat_interface.h>
 #include <KWayland/Server/shell_interface.h>
 #include <KWayland/Server/surface_interface.h>
@@ -48,6 +49,10 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <QOpenGLFramebufferObject>
 #include <QWindow>
 
+#include <sys/types.h>
+#include <unistd.h>
+#include <signal.h>
+
 using namespace KWayland::Server;
 
 static const QByteArray s_schemePropertyName = QByteArrayLiteral("KDE_COLOR_SCHEME_PATH");
@@ -1380,4 +1385,22 @@ bool ShellClient::dockWantsInput() const
     return false;
 }
 
+void ShellClient::killWindow()
+{
+    if (isInternal()) {
+        return;
+    }
+    if (!surface()) {
+        return;
+    }
+    auto c = surface()->client();
+    if (c->processId() == getpid()) {
+        c->destroy();
+        return;
+    }
+    ::kill(c->processId(), SIGTERM);
+    // give it time to terminate and only if terminate fails, try destroy Wayland connection
+    QTimer::singleShot(5000, c, &ClientConnection::destroy);
+}
+
 }

shell_client.h

@@ -132,6 +132,8 @@ public:
 
     void showOnScreenEdge() override;
 
+    void killWindow() override;
+
     // TODO: const-ref
     void placeIn(QRect &area);