fix: stop app.slice before logout/shutdown to ensure clean user process termination

Send SIGKILL to all processes in app.slice via systemd D-Bus KillUnit
before logout and shutdown.

Pms: BUG-350165,BUG-350171
Change-Id: Ibba4a31d93f107946af86b4b1e06a96a5ab4d0eb

Author: yixinshark

src/dde-session/impl/sessionmanager.cpp

@@ -174,6 +174,7 @@ void SessionManager::prepareLogout(bool force)
     stopRedshift();
     stopObexService();
     stopDock();
+    stopAppSlice();
 
     // 防止注销时，蓝牙音频设置没有断开连接
     disconnectAudioDevices();
@@ -513,6 +514,7 @@ void SessionManager::prepareShutdown(bool force)
 {
     stopSogouIme();
     stopBAMFDaemon();
+    stopAppSlice();
     preparePlayShutdownSound();
     stopPulseAudioService();
 
@@ -689,6 +691,22 @@ void SessionManager::stopDock()
     VIEW_SERVICE(DDE_DOCK_SERVICE);
 }
 
+bool SessionManager::killUnitProcesses(const QString &unit, int signal)
+{
+    auto reply = m_systemd1ManagerInter->KillUnit(unit, "all", signal);
+    if (reply.isError()) {
+        qWarning() << "failed to kill unit:" << unit << ", error:" << reply.error().name();
+        return false;
+    }
+
+    return true;
+}
+
+void SessionManager::stopAppSlice()
+{
+    killUnitProcesses(APP_SLICE, SIGKILL);
+}
+
 void SessionManager::disconnectAudioDevices()
 {
     auto msg = QDBusInterface("org.deepin.dde.Bluetooth1"

src/dde-session/impl/sessionmanager.h

@@ -91,6 +91,8 @@ public Q_SLOTS:
     void stopBAMFDaemon();
     void stopRedshift();
     void stopDock();
+    bool killUnitProcesses(const QString &unit, int signal);
+    void stopAppSlice();
     void disconnectAudioDevices();
 
     void preparePlayShutdownSound();

src/utils/utils.h

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2021 - 2023 UnionTech Software Technology Co., Ltd.
+// SPDX-FileCopyrightText: 2021 - 2026 UnionTech Software Technology Co., Ltd.
 //
 // SPDX-License-Identifier: GPL-3.0-or-later
 
@@ -16,6 +16,7 @@
 #define BAMFDAEMON_SERVICE "bamfdaemon.service"
 #define REDSHIFT_SERVICE "redshift.service"
 #define DDE_DOCK_SERVICE "dde-dock.service"
+#define APP_SLICE "app.slice"
 
 // sound
 #define SOUND_EFFECT_SCHEMA "com.deepin.dde.sound-effect"