refactor: Update IPC server to handle log level and elevate mode changes

src/apps/deskflow-daemon/deskflow-daemon.cpp

@@ -9,6 +9,7 @@
 #include "base/Log.h"
 #include "common/constants.h"
 #include "deskflow/DaemonApp.h"
+#include "deskflow/ipc/DaemonIpcServer.h"
 
 #include "arch/Arch.h"
 #include "base/EventQueue.h"
@@ -44,28 +45,58 @@ int main(int argc, char **argv)
   QCoreApplication app(argc, argv);
 
   const auto pDaemon = &DaemonApp::instance();
-  QObject::connect(pDaemon, &DaemonApp::mainLoopFinished, &app, &QCoreApplication::quit);
+  const auto initResult = pDaemon->init(&events, argc, argv);
-  QObject::connect(pDaemon, &DaemonApp::fatalErrorOccurred, &app, &QCoreApplication::quit);
-  QObject::connect(pDaemon, &DaemonApp::serviceInstalled, &app, &QCoreApplication::quit);
-  QObject::connect(pDaemon, &DaemonApp::serviceUninstalled, &app, &QCoreApplication::quit);
-  pDaemon->init(&events, argc, argv);
 
-  // Thread must be on the heap, as the thread needs to be deleted only when the loop finishes,
+  switch (initResult) {
-  // and not when we go out of scope.
+    using enum DaemonApp::InitResult;
-  // Deliberately do not set ownership of the thread to the daemon, as we want to delete the thread
-  // when the loop finishes, and not when the daemon is deleted.
-  QThread *thread = new QThread(); // NOSONAR
-  pDaemon->moveToThread(thread);
-  QObject::connect(thread, &QThread::started, pDaemon, &DaemonApp::run);
-  QObject::connect(thread, &QThread::finished, pDaemon, &QObject::deleteLater);
-  QObject::connect(thread, &QThread::finished, thread, &QThread::deleteLater);
-  thread->start();
 
-  return QCoreApplication::exec();
+  case StartDaemon: {
+    using namespace deskflow::core;
+
+    QCoreApplication app(argc, argv);
+
+    auto *pDaemonThread = new QThread(); // NOSONAR
+    pDaemon->moveToThread(pDaemonThread);
+
+    QObject::connect(pDaemonThread, &QThread::started, pDaemon, &DaemonApp::run);
+    QObject::connect(pDaemonThread, &QThread::finished, pDaemon, &QObject::deleteLater);
+    QObject::connect(pDaemonThread, &QThread::finished, pDaemonThread, &QThread::deleteLater);
+    QObject::connect(pDaemonThread, &QThread::finished, QCoreApplication::instance(), &QCoreApplication::quit);
+
+    // The daemon app is on it's own thread which doesn't have a Qt event loop, so we need to use direct connection.
+    auto *ipcServer = new ipc::DaemonIpcServer(&app); // NOSONAR
+    QObject::connect(
+        ipcServer, &ipc::DaemonIpcServer::logLevelChanged, pDaemon, &DaemonApp::saveLogLevel, //
+        Qt::DirectConnection
+    );
+    QObject::connect(
+        ipcServer, &ipc::DaemonIpcServer::elevateModeChanged, pDaemon, &DaemonApp::setElevate, //
+        Qt::DirectConnection
+    );
+    QObject::connect(
+        ipcServer, &ipc::DaemonIpcServer::commandChanged, pDaemon, &DaemonApp::setCommand, //
+        Qt::DirectConnection
+    );
+    QObject::connect(
+        ipcServer, &ipc::DaemonIpcServer::restartRequested, pDaemon, &DaemonApp::restartCoreProcess, //
+        Qt::DirectConnection
+    );
+    pDaemonThread->start();
+    return QCoreApplication::exec();
+  }
+
+  case FatalError:
+    return kExitFailed;
+
+  default:
+    return kExitSuccess;
+  }
 }
 
 #if SYSAPI_WIN32
 
+// Win32 subsystem entry point (simply forwards to main).
+// We need this because using regular main under the Win32 subsystem results in empty args.
 int WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int)
 {
   return main(__argc, __argv);

src/lib/common/common.h

@@ -1,7 +1,7 @@
 /*
  * Deskflow -- mouse and keyboard sharing utility
- * SPDX-FileCopyrightText: (C) 2012 - 2016 Symless Ltd.
+ * SPDX-FileCopyrightText: (C) 2010 - 2018, 2024 - 2025 Symless Ltd.
- * SPDX-FileCopyrightText: (C) 2002 Chris Schoeneman
+ * SPDX-FileCopyrightText: (C) 2002 - 2007 Chris Schoeneman
  * SPDX-License-Identifier: GPL-2.0-only WITH LicenseRef-OpenSSL-Exception
  */
 
@@ -22,8 +22,8 @@
 // make assert available since we use it a lot
 #include <assert.h>
 #include <stdint.h>
-#include <stdlib.h>
+#include <stdlib.h> // IWYU pragma: keep
-#include <string.h>
+#include <string.h> // IWYU pragma: keep
 
 // defined in Carbon
 #if !defined(__MACTYPES__)
@@ -35,10 +35,9 @@
 
 enum
 {
-  kExitSuccess = 0,     // successful completion
+  kExitSuccess = 0,    // successful completion
-  kExitFailed = 1,      // general failure
+  kExitFailed = 1,     // general failure
-  kExitTerminated = 2,  // killed by signal
+  kExitTerminated = 2, // killed by signal
-  kExitArgs = 3,        // bad arguments
+  kExitArgs = 3,       // bad arguments
-  kExitConfig = 4,      // cannot read configuration
+  kExitConfig = 4,     // cannot read configuration
-  kExitSubscription = 5 // subscription error
 };

src/lib/common/constants.h.in

@@ -1,8 +1,7 @@
 /*
  * Deskflow -- mouse and keyboard sharing utility
  * SPDX-FileCopyrightText: (C) 2024 Chris Rizzitello <sithlord48@gmail.com>
- * SPDX-FileCopyrightText: (C) 2012 - 2025 Symless Ltd.
+ * SPDX-FileCopyrightText: (C) 2025 Symless Ltd.
- * SPDX-FileCopyrightText: (C) 2002 Chris Schoeneman
  * SPDX-License-Identifier: GPL-2.0-only WITH LicenseRef-OpenSSL-Exception
  */
 

src/lib/deskflow/DaemonApp.cpp

@@ -1,6 +1,6 @@
 /*
  * Deskflow -- mouse and keyboard sharing utility
- * SPDX-FileCopyrightText: (C) 2012 Symless Ltd.
+ * SPDX-FileCopyrightText: (C) 2012 - 2025 Symless Ltd.
  * SPDX-License-Identifier: GPL-2.0-only WITH LicenseRef-OpenSSL-Exception
  */
 
@@ -19,7 +19,6 @@
 #include "deskflow/ArgParser.h"
 #include "deskflow/ClientArgs.h"
 #include "deskflow/ServerArgs.h"
-#include "ipc/DaemonIpcServer.h"
 #include "ipc/IpcClientProxy.h"
 #include "ipc/IpcLogOutputter.h"
 #include "ipc/IpcMessage.h"
@@ -37,16 +36,10 @@
 #define WIN32_LEAN_AND_MEAN
 #include <Windows.h>
 
-#elif SYSAPI_UNIX
-
-#include <iostream>
-
 #endif
 
-#include <QCoreApplication>
+#include <filesystem>
-#include <QObject>
+#include <iostream>
-#include <QThread>
-
 #include <memory>
 #include <sstream>
 #include <string>
@@ -99,13 +92,13 @@ int winMainLoopStatic(int, const char **)
 }
 #endif
 
-DaemonApp::DaemonApp() : m_ipcServer{new ipc::DaemonIpcServer(this)}
+void showHelp(int argc, char **argv) // NOSONAR - CLI args
 {
-  connect(m_ipcServer, &ipc::DaemonIpcServer::elevateModeChanged, this, &DaemonApp::handleElevateModeChanged);
+  const auto binName = argc > 0 ? std::filesystem::path(argv[0]).filename().string() : "deskflow-core";
-  connect(m_ipcServer, &ipc::DaemonIpcServer::commandChanged, this, &DaemonApp::handleCommandChanged);
+  std::cout << "Usage: " << binName << " daemon [-f|--foreground] [--install] [--uninstall]" << std::endl;
-  connect(m_ipcServer, &ipc::DaemonIpcServer::restartRequested, this, &DaemonApp::handleRestartRequested);
 }
 
+DaemonApp::DaemonApp() = default;
 DaemonApp::~DaemonApp() = default;
 
 void DaemonApp::run()
@@ -125,34 +118,62 @@ void DaemonApp::run()
     ARCH->daemonize(kAppName, unixMainLoopStatic);
 #endif
   }
-
-  Q_EMIT mainLoopFinished();
 }
 
-void DaemonApp::handleElevateModeChanged(int mode)
+void DaemonApp::saveLogLevel(const QString &logLevel) const
 {
-  LOG_DEBUG("elevate mode changed: %d", mode);
+  LOG_DEBUG("log level changed: %s", logLevel.toUtf8().constData());
-  m_elevateMode = mode;
+  CLOG->setFilter(logLevel.toUtf8().constData());
+
+  try {
+    // saves setting for next time the daemon starts.
+    ARCH->setting("LogLevel", logLevel.toStdString());
+  } catch (XArch &e) {
+    LOG((CLOG_ERR "failed to save log level setting: %s", e.what()));
+  }
 }
 
-void DaemonApp::handleCommandChanged(const QString &command)
+void DaemonApp::setElevate(bool elevate)
+{
+  LOG((CLOG_DEBUG "elevate value changed: %s", elevate ? "yes" : "no"));
+  m_elevate = elevate;
+
+  try {
+    // saves setting for next time the daemon starts.
+    ARCH->setting("Elevate", std::string(elevate ? "1" : "0"));
+  } catch (XArch &e) {
+    LOG((CLOG_ERR "failed to save elevate setting: %s", e.what()));
+  }
+}
+
+void DaemonApp::setCommand(const QString &command)
 {
   LOG_DEBUG("service command updated");
   m_command = command.toStdString();
+
+  try {
+    // saves setting for next time the daemon starts.
+    ARCH->setting("Command", command.toStdString());
+  } catch (XArch &e) {
+    LOG((CLOG_ERR "failed to save command setting: %s", e.what()));
+  }
 }
 
-void DaemonApp::handleRestartRequested()
+void DaemonApp::restartCoreProcess()
 {
   LOG_DEBUG("service restart requested");
+
 #if SYSAPI_WIN32
-  m_watchdog->setCommand(m_command, m_elevateMode);
+  m_watchdog->setCommand(m_command, m_elevate);
 #else
   LOG_ERR("restart not implemented on this platform");
 #endif
 }
 
-void DaemonApp::init(IEventQueue *events, int argc, char **argv) // NOSONAR
+DaemonApp::InitResult DaemonApp::init(IEventQueue *events, int argc, char **argv) // NOSONAR - CLI args
 {
+  using enum InitResult;
+
   if (events == nullptr) {
     throw XDeskflow("event queue not set");
   }
@@ -168,26 +189,30 @@ void DaemonApp::init(IEventQueue *events, int argc, char **argv) // NOSONAR
     for (int i = 1; i < argc; ++i) {
       string arg(argv[i]);
 
-      if (arg == "-f") {
+      if (arg == "-h" || arg == "--help") {
+        showHelp(argc, argv);
+        return ShowHelp;
+      } else if (arg == "-f" || arg == "--foreground") {
         m_foreground = true;
       }
 #if SYSAPI_WIN32
       else if (arg == "--install" || arg == "/install") {
         LOG((CLOG_NOTE "installing windows daemon"));
         ARCH->installDaemon();
-        Q_EMIT serviceInstalled();
+        return Installed;
       } else if (arg == "--uninstall" || arg == "/uninstall") {
         LOG((CLOG_NOTE "uninstalling windows daemon"));
         isUninstalling = true;
         ARCH->uninstallDaemon();
-        Q_EMIT serviceUninstalled();
+        return Uninstalled;
       }
 #endif
       else {
         stringstream ss;
         ss << "Unrecognized argument: " << arg;
-        foregroundError(ss.str().c_str());
+        handleError(ss.str().c_str());
-        Q_EMIT fatalErrorOccurred();
+        showHelp(argc, argv);
+        return ArgsError;
       }
     }
 
@@ -198,6 +223,9 @@ void DaemonApp::init(IEventQueue *events, int argc, char **argv) // NOSONAR
       CLOG->insert(new MSWindowsDebugOutputter()); // NOSONAR - Adopted by `Log`
 #endif
     }
+
+    return StartDaemon;
+
   } catch (XArch &e) {
     std::string message = e.what();
     if (isUninstalling && (message.find("The service has not been started") != std::string::npos)) {
@@ -207,16 +235,15 @@ void DaemonApp::init(IEventQueue *events, int argc, char **argv) // NOSONAR
       // horribly wrong, but it's just the service manager reporting a false
       // positive (the service has actually shut down in most cases).
     } else {
-      foregroundError(message.c_str());
+      handleError(message.c_str());
     }
-    Q_EMIT fatalErrorOccurred();
   } catch (std::exception &e) {
-    foregroundError(e.what());
+    handleError(e.what());
-    Q_EMIT fatalErrorOccurred();
   } catch (...) {
-    foregroundError("Unrecognized error.");
+    handleError("Unrecognized error.");
-    Q_EMIT fatalErrorOccurred();
   }
+
+  return FatalError;
 }
 
 void DaemonApp::mainLoop(bool logToFile, bool foreground)
@@ -268,12 +295,14 @@ void DaemonApp::mainLoop(bool logToFile, bool foreground)
   }
 }
 
-void DaemonApp::foregroundError(const char *message)
+void DaemonApp::handleError(const char *message)
 {
+  // Always print error to stdout in case run as CLI program.
+  LOG_ERR("%s", message);
+
 #if SYSAPI_WIN32
-  MessageBoxA(NULL, message, "Deskflow Service", MB_OK | MB_ICONERROR);
+  // Show a message box for when run from MSI in Win32 subsystem.
-#elif SYSAPI_UNIX
+  MessageBoxA(nullptr, message, "Deskflow daemon error", MB_OK | MB_ICONERROR);
-  cerr << message << endl;
 #endif
 }
 

src/lib/deskflow/DaemonApp.h

@@ -1,6 +1,6 @@
 /*
  * Deskflow -- mouse and keyboard sharing utility
- * SPDX-FileCopyrightText: (C) 2012 Symless Ltd.
+ * SPDX-FileCopyrightText: (C) 2012 - 2025 Symless Ltd.
  * SPDX-License-Identifier: GPL-2.0-only WITH LicenseRef-OpenSSL-Exception
  */
 
@@ -37,9 +37,23 @@ class DaemonApp : public QObject
   Q_OBJECT
 
 public:
-  void init(IEventQueue *events, int argc, char **argv);
+  enum class InitResult
+  {
+    Installed,
+    Uninstalled,
+    StartDaemon,
+    ShowHelp,
+    ArgsError,
+    FatalError,
+  };
+
+  InitResult init(IEventQueue *events, int argc, char **argv);
   void run();
   void mainLoop(bool logToFile, bool foreground = false);
+  void restartCoreProcess();
+  void saveLogLevel(const QString &logLevel) const;
+  void setElevate(bool elevate);
+  void setCommand(const QString &command);
 
   static DaemonApp &instance()
   {
@@ -47,25 +61,14 @@ public:
     return instance;
   }
 
-signals:
-  void mainLoopFinished();
-  void fatalErrorOccurred();
-  void serviceInstalled();
-  void serviceUninstalled();
-
 private:
   explicit DaemonApp();
   ~DaemonApp() override;
 
   void daemonize();
-  void foregroundError(const char *message);
+  void handleError(const char *message);
   std::string logFilename();
-  void handleIpcMessage(const Event &, void *);
+  void handleIpcMessage(const Event &e, void *);
-
-private slots:
-  void handleElevateModeChanged(int mode);
-  void handleCommandChanged(const QString &command);
-  void handleRestartRequested();
 
 #if SYSAPI_WIN32
   std::unique_ptr<MSWindowsWatchdog> m_watchdog;
@@ -77,6 +80,6 @@ private:
   FileLogOutputter *m_fileLogOutputter = nullptr;
   deskflow::core::ipc::DaemonIpcServer *m_ipcServer = nullptr;
   std::string m_command = "";
-  int m_elevateMode = 0;
+  bool m_elevate = false;
   bool m_foreground = false;
 };

src/lib/deskflow/ipc/DaemonIpcServer.cpp

@@ -100,15 +100,27 @@ void DaemonIpcServer::processMessage(QLocalSocket *clientSocket, const QString &
   LOG_DEBUG("ipc server got message: %s", message.toUtf8().constData());
   if (message == "hello") {
     clientSocket->write("hello\n");
+  } else if (message == "noop") {
+    clientSocket->write(kAckMessage);
+  } else if (message.startsWith("logLevel=")) {
+    const auto logLevel = message.split('=')[1];
+    if (logLevel.isEmpty()) {
+      LOG_ERR("ipc server got empty log level");
+      clientSocket->write(kErrorMessage);
+    } else {
+      LOG_DEBUG("ipc server got new log level: %s", logLevel.toUtf8().constData());
+      Q_EMIT logLevelChanged(logLevel);
+      clientSocket->write(kAckMessage);
+    }
   } else if (message.startsWith("elevate=")) {
-    const auto elevateMode = message.split('=')[1].toInt();
+    const auto elevateMode = message.split('=')[1];
-    if (elevateMode < 0 || elevateMode > 2) {
+    if (elevateMode != "yes" && elevateMode != "no") {
-      LOG_ERR("ipc server got invalid elevate mode: %d", elevateMode);
+      LOG_ERR("ipc server got invalid elevate value: %s", elevateMode.toUtf8().constData());
       clientSocket->write(kErrorMessage);
       return;
     } else {
-      LOG_DEBUG("ipc server got new elevate mode: %d", elevateMode);
+      LOG_DEBUG("ipc server got new elevate value: %s", elevateMode.toUtf8().constData());
-      Q_EMIT elevateModeChanged(elevateMode);
+      Q_EMIT elevateModeChanged(elevateMode == "yes");
       clientSocket->write(kAckMessage);
     }
   } else if (message.startsWith("command=")) {

src/lib/deskflow/ipc/DaemonIpcServer.h

@@ -23,7 +23,8 @@ public:
   ~DaemonIpcServer();
 
 signals:
-  void elevateModeChanged(int mode);
+  void logLevelChanged(const QString &logLevel);
+  void elevateModeChanged(bool elevate);
   void commandChanged(const QString &command);
   void restartRequested();