Qtの基礎 - シャットダウン

概要

Qtライブラリを使用して、ソフトウェアからOSのシャットダウンや再起動等を行う方法を記載する。

シャットダウン

• shutdownコマンドを実行する場合

 #include <QProcess>
 #include <QInputDialog>
 
 void Converter::shutdown()
 {
    // GNOME Power Managementコマンドを試行
    if (QProcess::startDetached("gnome-power-cmd.sh shutdown") || QProcess::startDetached("gnome-power-cmd shutdown")) {
       qInfo() << "Shutdown initiated via GNOME Power Management command.";
       return;
    }
 
    // sudo shutdownを試行
    qWarning() << "Attempting to shutdown using sudo. This requires root privileges.";
 
    // パスワード入力ダイアログを表示
    bool ok;
    QString password = QInputDialog::getText(this, "Sudo Password", "Enter your sudo password to proceed with shutdown:",
                                             QLineEdit::Password, QString(), &ok);
 
    if (!ok || password.isEmpty()) {
       qWarning() << "Shutdown cancelled: No password provided.";
       qCritical() << "All shutdown methods failed.";
       return;
    }
 
    // sudoコマンドを実行
    QProcess process;
    process.start("sudo", QStringList() << "-S" << "shutdown" << "-P" << "now");
 
    if (!process.waitForStarted()) {
       qCritical() << "Failed to start sudo process:" << process.errorString();
       qCritical() << "All shutdown methods failed.";
       return;
    }
 
    // パスワードを入力
    process.write(password.toUtf8() + "\n");
 
    // プロセスの終了を待つ
    if (!process.waitForFinished()) {
       qCritical() << "Shutdown process did not finish:" << process.errorString();
       qCritical() << "All shutdown methods failed.";
       return;
    }
 
    // 終了コードを確認
    if (process.exitCode() != 0) {
       qCritical() << "Shutdown failed. Exit code:" << process.exitCode();
       qCritical() << "Error output:" << process.readAllStandardError();
       qCritical() << "All shutdown methods failed.";
       return;
    }
 
    qInfo() << "Shutdown initiated via sudo command.";
 }

• D-Busを使用する場合

 #include <QDBus>
 #include <QDebug>
 
 void Converter::shutdown()
 {
    // GNOMEセッションマネージャを試行
    QDBusInterface gnomeSessionManager("org.gnome.SessionManager",
                                       "/org/gnome/SessionManager",
                                       "org.gnome.SessionManager",
                                       QDBusConnection::sessionBus());
    if (gnomeSessionManager.isValid()) {
       QDBusReply<void> reply = gnomeSessionManager.call("RequestShutdown");
       if (reply.isValid()) {
          qInfo() << "Shutdown initiated via GNOME Session Manager.";
           return;
       }
       qWarning() << "GNOME Session Manager shutdown failed:" << reply.error().message();
    }
 
    // KDEセッションマネージャを試行
    QDBusInterface kdeSessionManager("org.kde.ksmserver",
                                     "/KSMServer",
                                     "org.kde.KSMServerInterface",
                                     QDBusConnection::sessionBus());
    if (kdeSessionManager.isValid()) {
       QDBusReply<void> reply = kdeSessionManager.call("logout", 0, 2, 2);
       if (reply.isValid()) {
          qInfo() << "Shutdown initiated via KDE Session Manager.";
          return;
       }
       qWarning() << "KDE Session Manager shutdown failed:" << reply.error().message();
    }
 
    // HAL (Hardware Abstraction Layer) を試行
    QDBusInterface halPower("org.freedesktop.Hal",
                            "/org/freedesktop/Hal/devices/computer",
                            "org.freedesktop.Hal.Device.SystemPowerManagement",
                            QDBusConnection::systemBus());
    if (halPower.isValid()) {
       QDBusReply<void> reply = halPower.call("Shutdown");
       if (reply.isValid()) {
          qInfo() << "Shutdown initiated via HAL.";
          return;
       }
       qWarning() << "HAL shutdown failed:" << reply.error().message();
    }
 
    // ConsoleKitを試行
    QDBusInterface consoleKit("org.freedesktop.ConsoleKit",
                              "/org/freedesktop/ConsoleKit/Manager",
                              "org.freedesktop.ConsoleKit.Manager",
                              QDBusConnection::systemBus());
    if (consoleKit.isValid()) {
       QDBusReply<void> reply = consoleKit.call("Stop");
       if (reply.isValid()) {
          qInfo() << "Shutdown initiated via ConsoleKit.";
          return;
       }
       qWarning() << "ConsoleKit shutdown failed:" << reply.error().message();
    }
 
    qCritical() << "All shutdown methods failed.";
 }

再起動

 void Converter::reboot()
 {
    bool reboot_works = false;
    bool gnome_power1 = false;
    bool gnome_power2 = false;
    bool hal_works = false;
    QDBusMessage response;
 
    // GNOME
    QDBusInterface gnomeSessionManager("org.gnome.SessionManager", "/org/gnome/SessionManager", "org.gnome.SessionManager", QDBusConnection::sessionBus());
    response = gnomeSessionManager.call("RequestReboot");
    if(response.type() == QDBusMessage::ErrorMessage)
    {
       if(verbose)
       {
          qWarning() << "W: " << response.errorName() << ":" << response.errorMessage();
       }
       gnome_power1 = QProcess::startDetached("gnome-power-cmd.sh reboot");
       gnome_power2 = QProcess::startDetached("gnome-power-cmd reboot");
       if(verbose && !gnome_power1 && !gnome_power2)
       {
          qWarning() << "W: gnome-power-cmd and gnome-power-cmd.sh didn't work";
       }
    }
    else
    {
       reboot_works = true;
    }
 
    // KDE
    QDBusInterface kdeSessionManager("org.kde.ksmserver", "/KSMServer", "org.kde.KSMServerInterface", QDBusConnection::sessionBus());
    response = kdeSessionManager.call("logout", 0, 2, 1);
 
    if(response.type() == QDBusMessage::ErrorMessage)
    {
       if(verbose)
       {
          qWarning() << "W: " << response.errorName() << ":" << response.errorMessage();
       }
    }
    else
    {
       reboot_works = true;
    }
 
    if(!reboot_works && !gnome_power1 && !gnome_power2)
    {
       QDBusInterface powermanagement("org.freedesktop.Hal", "/org/freedesktop/Hal/devices/computer", "org.freedesktop.Hal.Device.SystemPowerManagement",
                                      QDBusConnection::systemBus());
       response = powermanagement.call("Reboot");
       if(response.type() == QDBusMessage::ErrorMessage)
       {
          if(verbose)
          {
             qWarning() << "W: " << response.errorName() << ":" << response.errorMessage();
          }
       }
       else
       {
          hal_works = true;
       }
    }
 
    if(!hal_works && !reboot_works && !gnome_power1 && !gnome_power2)
    {
       QDBusInterface powermanagement("org.freedesktop.ConsoleKit", "/org/freedesktop/ConsoleKit/Manager", "org.freedesktop.ConsoleKit.Manager",
                                      QDBusConnection::systemBus());
       response = powermanagement.call("Restart");
 
       if(response.type() == QDBusMessage::ErrorMessage)
       {
          if(verbose)
          {
             qWarning() << "W: " << response.errorName() << ":" << response.errorMessage();
          }
          QProcess::startDetached("sudo shutdown -r now");
       }
    }
 }

サスペンド(スリープ)

 void Converter::suspend()
 {
    bool gnome_power1 = false;
    bool gnome_power2 = false;
    bool hal_works = false;
    QDBusMessage response;
 
    gnome_power1 = QProcess::startDetached("gnome-power-cmd.sh suspend");
    gnome_power2 = QProcess::startDetached("gnome-power-cmd suspend");
 
    if(!gnome_power1 && !gnome_power2 && verbose)
    {
       qWarning() << "W: gnome-power-cmd and gnome-power-cmd.sh didn't work";
    }
 
    if(!gnome_power1 && !gnome_power2)
    {
       QDBusInterface powermanagement("org.freedesktop.Hal", "/org/freedesktop/Hal/devices/computer",
                                      "org.freedesktop.Hal.Device.SystemPowerManagement", QDBusConnection::systemBus());
       response = powermanagement.call("Suspend", 0);
 
       if(response.type() == QDBusMessage::ErrorMessage)
       {
          if(verbose)
          {
             qWarning() << "W: " << response.errorName() << ":" << response.errorMessage();
          }
       }
       else
       {
          hal_works = true;
       }
    }
 
    if(!hal_works && !gnome_power1 && !gnome_power2)
    {
       QDBusInterface powermanagement("org.freedesktop.DeviceKit.Power", "/org/freedesktop/DeviceKit/Power",
                                      "org.freedesktop.DeviceKit.Power", QDBusConnection::systemBus());
       response = powermanagement.call("Suspend");
 
       if(response.type() == QDBusMessage::ErrorMessage)
       {
          if(verbose)
          {
             qWarning() << "W: " << response.errorName() << ":" << response.errorMessage();
          }
       }
    }
 }

ハイバネート

• GNOME Power Managementコマンドを実行する場合

 #include <QProcess>
 
 void Converter::hibernate()
 {
    // GNOME Power Management コマンドを試行
    if (QProcess::startDetached("gnome-power-cmd.sh hibernate") ||
       QProcess::startDetached("gnome-power-cmd hibernate")) {
       qInfo() << "Hibernation initiated via GNOME Power Management.";
       return;
    }
 
    qWarning() << "GNOME Power Management commands failed. Trying DBus methods.";
 }

• D-Busを使用する場合

 #include <QDBusInterface>
 #include <QDBusReply>
 #include <QDebug>
 
 void Converter::hibernate()
 {
    // HAL (Hardware Abstraction Layer) を試行
    QDBusInterface halPower("org.freedesktop.Hal", 
                            "/org/freedesktop/Hal/devices/computer",
                            "org.freedesktop.Hal.Device.SystemPowerManagement", 
                            QDBusConnection::systemBus());
 
    if (halPower.isValid()) {
       QDBusReply<void> reply = halPower.call("Hibernate");
       if (reply.isValid()) {
          qInfo() << "Hibernation initiated via HAL.";
          return;
       }
       qWarning() << "HAL hibernation failed:" << reply.error().message();
    }
    else {
       qWarning() << "Failed to connect to HAL power management.";
    }
 
    // DeviceKit Powerを試行
    QDBusInterface dkPower("org.freedesktop.DeviceKit.Power", 
                           "/org/freedesktop/DeviceKit/Power",
                           "org.freedesktop.DeviceKit.Power", 
                           QDBusConnection::systemBus());
    
    if (dkPower.isValid()) {
        QDBusReply<void> reply = dkPower.call("Hibernate");
        if (reply.isValid()) {
            qInfo() << "Hibernation initiated via DeviceKit Power.";
            return;
       }
       qWarning() << "DeviceKit Power hibernation failed:" << reply.error().message();
    }
    else {
       qWarning() << "Failed to connect to DeviceKit Power.";
    }
 
    qCritical() << "All hibernation methods failed.";
 }

画面のロック

QDBusモジュールを使用して、GNOMEスクリーンセーバーのD-Busインターフェースに接続して、Lockメソッドを呼び出してスクリーンをロックしている。

 #include <QDBus>
 #include <QMessageBox>
 
 void Converter::lock()
 {
    QDBusInterface screensaver("org.gnome.ScreenSaver", "/org/gnome/ScreenSaver", "org.gnome.ScreenSaver");
 
    if (!screensaver.isValid()) {
        QMessageBox::warning(this, "Error", "Unable to connect to GNOME ScreenSaver.", QMessageBox::Ok);
        return;
    }
 
    QDBusReply<void> reply = screensaver.call("Lock");
 
    if (!reply.isValid()) {
        QMessageBox::warning(this, "Error", "Unable to lock computer: " + reply.error().message(), QMessageBox::Ok);
    }
 }