Revert "systemd: Set up a watchdog"

kwin_wayland has become unstable. Sometimes it works fine, sometimes it
is randomly killed. Things are quite bad after kwin_wayland --replace.

This reverts commit 71ade59f4b.

CMakeLists.txt

@@ -355,9 +355,6 @@ set_package_properties(QAccessibilityClient6 PROPERTIES
 )
 set(HAVE_ACCESSIBILITY ${QAccessibilityClient6_FOUND})
 
-pkg_check_modules(libsystemd IMPORTED_TARGET libsystemd)
-add_feature_info(libsystemd libsystemd_FOUND "Required for setting up the service watchdog")
-
 option(KWIN_BUILD_GLOBALSHORTCUTS "Enable building of KWin with global shortcuts support" ON)
 if(KWIN_BUILD_GLOBALSHORTCUTS)
     find_package(KGlobalAccelD REQUIRED)

plasma-kwin_wayland.service.in

@@ -3,10 +3,6 @@ Description=KDE Window Manager
 PartOf=graphical-session.target
 
 [Service]
-Type=notify-reload
 ExecStart=@CMAKE_INSTALL_FULL_BINDIR@/kwin_wayland_wrapper --xwayland
 BusName=org.kde.KWinWrapper
 Slice=session.slice
-WatchdogSec=5s
-NotifyAccess=all
-WatchdogSignal=SIGHUP

src/CMakeLists.txt

@@ -355,11 +355,6 @@ if (KWIN_BUILD_TABBOX)
     add_subdirectory(tabbox/switchers)
 endif()
 
-if(TARGET PkgConfig::libsystemd)
-    target_sources(kwin PRIVATE watchdog.cpp)
-    target_link_libraries(kwin PRIVATE PkgConfig::libsystemd)
-endif()
-
 qt_generate_dbus_interface(virtualkeyboard_dbus.h org.kde.kwin.VirtualKeyboard.xml OPTIONS -A)
 qt_generate_dbus_interface(tabletmodemanager.h org.kde.KWin.TabletModeManager.xml OPTIONS -A)
 

src/helpers/wayland_wrapper/kwin_wrapper.cpp

@@ -42,10 +42,7 @@ class KWinWrapper : public QObject
 public:
     KWinWrapper(QObject *parent);
     ~KWinWrapper();
-
     void run();
-    void restart();
-    void terminate();
 
 private:
     wl_socket *m_socket;
@@ -85,7 +82,13 @@ KWinWrapper::KWinWrapper(QObject *parent)
 KWinWrapper::~KWinWrapper()
 {
     wl_socket_destroy(m_socket);
-    terminate();
+    if (m_kwinProcess) {
+        disconnect(m_kwinProcess, nullptr, this, nullptr);
+        m_kwinProcess->terminate();
+        m_kwinProcess->waitForFinished();
+        m_kwinProcess->kill();
+        m_kwinProcess->waitForFinished();
+    }
 }
 
 void KWinWrapper::run()
@@ -144,6 +147,7 @@ void KWinWrapper::run()
             env.insert("XAUTHORITY", m_xauthorityFile.fileName());
         }
     }
+
     auto envSyncJob = new KUpdateLaunchEnvironmentJob(env);
     connect(envSyncJob, &KUpdateLaunchEnvironmentJob::finished, this, []() {
         // The service name is merely there to indicate to the world that we're up and ready with all envs exported
@@ -151,42 +155,21 @@ void KWinWrapper::run()
     });
 }
 
-void KWinWrapper::terminate()
-{
-    if (m_kwinProcess) {
-        disconnect(m_kwinProcess, nullptr, this, nullptr);
-        m_kwinProcess->terminate();
-        m_kwinProcess->waitForFinished();
-        m_kwinProcess->kill();
-        m_kwinProcess->waitForFinished();
-    }
-}
-
-void KWinWrapper::restart()
-{
-    terminate();
-    m_kwinProcess->start();
-}
-
 int main(int argc, char **argv)
 {
     QCoreApplication app(argc, argv);
     app.setQuitLockEnabled(false); // don't exit when the first KJob finishes
 
     KSignalHandler::self()->watchSignal(SIGTERM);
-    KSignalHandler::self()->watchSignal(SIGHUP);
+    QObject::connect(KSignalHandler::self(), &KSignalHandler::signalReceived, &app, [&app](int signal) {
+        if (signal == SIGTERM) {
+            app.quit();
+        }
+    });
 
     KWinWrapper wrapper(&app);
     wrapper.run();
 
-    QObject::connect(KSignalHandler::self(), &KSignalHandler::signalReceived, &app, [&app, &wrapper](int signal) {
-        if (signal == SIGTERM) {
-            app.quit();
-        } else if (signal == SIGHUP) { // The systemd service will issue SIGHUP when it's locked up so that we can restarted
-            wrapper.restart();
-        }
-    });
-
     return app.exec();
 }
 

src/watchdog.cpp

@@ -1,62 +0,0 @@
-/*
-    KWin - the KDE window manager
-    This file is part of the KDE project.
-
-    SPDX-FileCopyrightText: 2024 Aleix Pol i Gonzalez <aleix.pol_gonzalez@mbition.io>
-
-    SPDX-License-Identifier: GPL-2.0-or-later
-*/
-
-#include "utils/common.h"
-#include <QCoreApplication>
-#include <QTimer>
-#include <systemd/sd-daemon.h>
-
-class Watchdog : public QObject
-{
-    Q_OBJECT
-public:
-    Watchdog(QObject *parent)
-        : QObject(parent)
-    {
-        bool ok;
-        const std::chrono::microseconds watchdogIntervalInUs((qgetenv("WATCHDOG_USEC").toUInt(&ok) * 3) / 4);
-        if (!ok) {
-            qCInfo(KWIN_CORE) << "Watchdog: disabled, not running on a systemd environment or watchdog is not set up. No WATCHDOG_USEC.";
-            deleteLater();
-            return;
-        }
-        m_onBehalf = qgetenv("WATCHDOG_PID").toUInt(&ok);
-        if (!ok) {
-            qCInfo(KWIN_CORE) << "Watchdog: disabled, not running on a systemd environment or watchdog is not set up. No WATCHDOG_PID.";
-            deleteLater();
-            return;
-        }
-        qunsetenv("WATCHDOG_USEC");
-        qunsetenv("WATCHDOG_PID");
-        auto t = new QTimer(this);
-        t->setInterval(std::chrono::duration_cast<std::chrono::milliseconds>(watchdogIntervalInUs));
-        t->setSingleShot(false);
-        qCInfo(KWIN_CORE) << "Watchdog: enabled. Interval:" << watchdogIntervalInUs << t->intervalAsDuration();
-
-        sd_pid_notify(m_onBehalf, 0, "READY=1"); // If service Type=notify the service is only considered ready once we send this
-        qCInfo(KWIN_CORE) << "Watchdog: Notified as ready";
-
-        connect(t, &QTimer::timeout, this, [this] {
-            sd_pid_notify(m_onBehalf, 0, "WATCHDOG=1");
-        });
-        t->start();
-    }
-
-private:
-    pid_t m_onBehalf = 0;
-};
-
-static void setupWatchdog()
-{
-    new Watchdog(QCoreApplication::instance());
-}
-
-Q_COREAPP_STARTUP_FUNCTION(setupWatchdog)
-
-#include "watchdog.moc"