Bring back Qt4 X11 session management functionality.

Added QXcbSessionManager to the Xcb plugin.
QXcbSessionManager inherits from QPlatformSessionManager, it's a port of
QSessionManager as it is in Qt 4.8.
Minor changes also in QPlatformSessionManager and QGuiApplication to
hook it up.

Task-number: QTBUG-28228
Task-number: QTBUG-30011
Task-number: QTBUG-33033
Change-Id: I50b33d05a1e32c5278dea339f693713acc870a70
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: David Faure <david.faure@kdab.com>

11 files changed, 670 insertions, 4 deletions

diff --git a/configure b/configure
index 1e7f01c3f8..d376c1d719 100755
--- a/configure
+++ b/configure
@@ -5348,6 +5348,12 @@ if [ "$CFG_XCB" != "no" ]; then
             QT_CONFIG="$QT_CONFIG xcb-xlib"
         fi
 
+        if [ "$CFG_SM" != "no" ] && [ -n "$PKG_CONFIG" ]; then
+            if $PKG_CONFIG --exists "sm" 2>/dev/null && $PKG_CONFIG --exists "ice" 2>/dev/null; then
+                QT_CONFIG="$QT_CONFIG xcb-sm"
+            fi
+        fi
+
         # auto-detect Xrender support
         if [ "$CFG_XRENDER" != "no" ]; then
             if compileTest x11/xrender "Xrender"; then
diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index 882eefb60e..7f258331d3 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -1162,9 +1162,9 @@ void QGuiApplicationPrivate::init()
     init_plugins(pluginList);
     QWindowSystemInterface::flushWindowSystemEvents();
 
+#ifndef QT_NO_SESSIONMANAGER
     Q_Q(QGuiApplication);
 
-#ifndef QT_NO_SESSIONMANAGER
     // connect to the session manager
     session_manager = new QSessionManager(q, session_id, session_key);
 #endif
diff --git a/src/gui/kernel/qguiapplication.h b/src/gui/kernel/qguiapplication.h
index a0aef83eed..bd42f18418 100644
--- a/src/gui/kernel/qguiapplication.h
+++ b/src/gui/kernel/qguiapplication.h
@@ -184,6 +184,9 @@ private:
 #endif
     friend class QFontDatabasePrivate;
     friend class QPlatformIntegration;
+#ifndef QT_NO_SESSIONMANAGER
+    friend class QPlatformSessionManager;
+#endif
 };
 
 QT_END_NAMESPACE
diff --git a/src/gui/kernel/qplatformsessionmanager.cpp b/src/gui/kernel/qplatformsessionmanager.cpp
index 6eb88a9450..97c40d863c 100644
--- a/src/gui/kernel/qplatformsessionmanager.cpp
+++ b/src/gui/kernel/qplatformsessionmanager.cpp
@@ -1,6 +1,7 @@
 /****************************************************************************
 **
 ** Copyright (C) 2013 Samuel Gaist <samuel.gaist@edeltech.ch>
+** Copyright (C) 2013 Teo Mrnjavac <teo@kde.org>
 ** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
 ** Contact: http://www.qt-project.org/legal
 **
@@ -42,6 +43,10 @@
 
 #include "qplatformsessionmanager.h"
 
+#include "qguiapplication_p.h"
+
+#ifndef QT_NO_SESSIONMANAGER
+
 QT_BEGIN_NAMESPACE
 
 QPlatformSessionManager::QPlatformSessionManager(const QString &id, const QString &key)
@@ -113,6 +118,12 @@ QStringList QPlatformSessionManager::discardCommand() const
     return m_discardCommand;
 }
 
+void QPlatformSessionManager::setManagerProperty(const QString &name, const QString &value)
+{
+    Q_UNUSED(name)
+    Q_UNUSED(value)
+}
+
 void QPlatformSessionManager::setManagerProperty(const QString &name, const QStringList &value)
 {
     Q_UNUSED(name)
@@ -128,4 +139,16 @@ void QPlatformSessionManager::requestPhase2()
 {
 }
 
+void QPlatformSessionManager::appCommitData()
+{
+    qGuiApp->d_func()->commitData();
+}
+
+void QPlatformSessionManager::appSaveState()
+{
+    qGuiApp->d_func()->saveState();
+}
+
 QT_END_NAMESPACE
+
+#endif // QT_NO_SESSIONMANAGER
diff --git a/src/gui/kernel/qplatformsessionmanager.h b/src/gui/kernel/qplatformsessionmanager.h
index 0389a7b076..23b7a62436 100644
--- a/src/gui/kernel/qplatformsessionmanager.h
+++ b/src/gui/kernel/qplatformsessionmanager.h
@@ -1,6 +1,7 @@
 /****************************************************************************
 **
 ** Copyright (C) 2013 Samuel Gaist <samuel.gaist@edeltech.ch>
+** Copyright (C) 2013 Teo Mrnjavac <teo@kde.org>
 ** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
 ** Contact: http://www.qt-project.org/legal
 **
@@ -57,6 +58,8 @@
 
 #include <QtGui/qsessionmanager.h>
 
+#ifndef QT_NO_SESSIONMANAGER
+
 QT_BEGIN_NAMESPACE
 
 class Q_GUI_EXPORT QPlatformSessionManager
@@ -82,16 +85,22 @@ public:
     virtual void setDiscardCommand(const QStringList &command);
     virtual QStringList discardCommand() const;
 
+    virtual void setManagerProperty(const QString &name, const QString &value);
     virtual void setManagerProperty(const QString &name, const QStringList &value);
 
     virtual bool isPhase2() const;
     virtual void requestPhase2();
 
+protected:
+    virtual void appCommitData();
+    virtual void appSaveState();
+
+    QString m_sessionId;
+    QString m_sessionKey;
+
 private:
     QStringList m_restartCommand;
     QStringList m_discardCommand;
-    const QString m_sessionId;
-    const QString m_sessionKey;
     QSessionManager::RestartHint m_restartHint;
 
     Q_DISABLE_COPY(QPlatformSessionManager)
@@ -99,4 +108,6 @@ private:
 
 QT_END_NAMESPACE
 
+#endif // QT_NO_SESSIONMANAGER
+
 #endif // QPLATFORMSESSIONMANAGER_H
diff --git a/src/gui/kernel/qsessionmanager.cpp b/src/gui/kernel/qsessionmanager.cpp
index 8ac3c24a8f..8cc8d3d961 100644
--- a/src/gui/kernel/qsessionmanager.cpp
+++ b/src/gui/kernel/qsessionmanager.cpp
@@ -365,7 +365,8 @@ QStringList QSessionManager::discardCommand() const
 void QSessionManager::setManagerProperty(const QString &name,
                                          const QString &value)
 {
-    setManagerProperty(name, QStringList(value));
+    Q_D(QSessionManager);
+    d->platformSessionManager->setManagerProperty(name, value);
 }
 
 /*!
diff --git a/src/plugins/platforms/xcb/qxcbintegration.cpp b/src/plugins/platforms/xcb/qxcbintegration.cpp
index 68ad93143b..e10c556473 100644
--- a/src/plugins/platforms/xcb/qxcbintegration.cpp
+++ b/src/plugins/platforms/xcb/qxcbintegration.cpp
@@ -50,6 +50,10 @@
 #include "qxcbclipboard.h"
 #include "qxcbdrag.h"
 
+#ifndef QT_NO_SESSIONMANAGER
+#include "qxcbsessionmanager.h"
+#endif
+
 #include <xcb/xcb.h>
 
 #include <QtPlatformSupport/private/qgenericunixeventdispatcher_p.h>
@@ -439,4 +443,11 @@ QByteArray QXcbIntegration::wmClass() const
     return m_wmClass;
 }
 
+#ifndef QT_NO_SESSIONMANAGER
+QPlatformSessionManager *QXcbIntegration::createPlatformSessionManager(const QString &id, const QString &key) const
+{
+    return new QXcbSessionManager(id, key);
+}
+#endif
+
 QT_END_NAMESPACE
diff --git a/src/plugins/platforms/xcb/qxcbintegration.h b/src/plugins/platforms/xcb/qxcbintegration.h
index 09fc0d32b5..7fd5756fd5 100644
--- a/src/plugins/platforms/xcb/qxcbintegration.h
+++ b/src/plugins/platforms/xcb/qxcbintegration.h
@@ -101,6 +101,10 @@ public:
 
     QByteArray wmClass() const;
 
+#ifndef QT_NO_SESSIONMANAGER
+    QPlatformSessionManager *createPlatformSessionManager(const QString &id, const QString &key) const Q_DECL_OVERRIDE;
+#endif
+
 private:
     QList<QXcbConnection *> m_connections;
 
diff --git a/src/plugins/platforms/xcb/qxcbsessionmanager.cpp b/src/plugins/platforms/xcb/qxcbsessionmanager.cpp
new file mode 100644
index 0000000000..6abe24b7ab
--- /dev/null
+++ b/src/plugins/platforms/xcb/qxcbsessionmanager.cpp
@@ -0,0 +1,512 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Teo Mrnjavac <teo@kde.org>
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qxcbsessionmanager.h"
+
+#include <qguiapplication.h>
+#include <qdatetime.h>
+#include <qfileinfo.h>
+#include <qplatformdefs.h>
+#include <qsocketnotifier.h>
+#include <X11/SM/SMlib.h>
+
+
+class QSmSocketReceiver : public QObject
+{
+    Q_OBJECT
+public:
+    QSmSocketReceiver(int socket)
+    {
+        QSocketNotifier* sn = new QSocketNotifier(socket, QSocketNotifier::Read, this);
+        connect(sn, SIGNAL(activated(int)), this, SLOT(socketActivated(int)));
+    }
+
+public Q_SLOTS:
+     void socketActivated(int);
+};
+
+
+static SmcConn smcConnection = 0;
+static bool sm_interactionActive;
+static bool sm_smActive;
+static int sm_interactStyle;
+static int sm_saveType;
+static bool sm_cancel;
+static bool sm_waitingForInteraction;
+static bool sm_isshutdown;
+static bool sm_phase2;
+static bool sm_in_phase2;
+bool qt_sm_blockUserInput = false;
+
+static QSmSocketReceiver* sm_receiver = 0;
+
+static void resetSmState();
+static void sm_setProperty(const char *name, const char *type,
+                            int num_vals, SmPropValue *vals);
+static void sm_saveYourselfCallback(SmcConn smcConn, SmPointer clientData,
+                                  int saveType, Bool shutdown , int interactStyle, Bool fast);
+static void sm_saveYourselfPhase2Callback(SmcConn smcConn, SmPointer clientData) ;
+static void sm_dieCallback(SmcConn smcConn, SmPointer clientData) ;
+static void sm_shutdownCancelledCallback(SmcConn smcConn, SmPointer clientData);
+static void sm_saveCompleteCallback(SmcConn smcConn, SmPointer clientData);
+static void sm_interactCallback(SmcConn smcConn, SmPointer clientData);
+static void sm_performSaveYourself(QXcbSessionManager*);
+
+static void resetSmState()
+{
+    sm_waitingForInteraction = false;
+    sm_interactionActive = false;
+    sm_interactStyle = SmInteractStyleNone;
+    sm_smActive = false;
+    qt_sm_blockUserInput = false;
+    sm_isshutdown = false;
+    sm_phase2 = false;
+    sm_in_phase2 = false;
+}
+
+
+// theoretically it's possible to set several properties at once. For
+// simplicity, however, we do just one property at a time
+static void sm_setProperty(const char *name, const char *type,
+                            int num_vals, SmPropValue *vals)
+{
+    if (num_vals) {
+      SmProp prop;
+      prop.name = const_cast<char*>(name);
+      prop.type = const_cast<char*>(type);
+      prop.num_vals = num_vals;
+      prop.vals = vals;
+
+      SmProp* props[1];
+      props[0] = &prop;
+      SmcSetProperties(smcConnection, 1, props);
+    } else {
+      char* names[1];
+      names[0] = const_cast<char*>(name);
+      SmcDeleteProperties(smcConnection, 1, names);
+    }
+}
+
+static void sm_setProperty(const QString &name, const QString &value)
+{
+    QByteArray v = value.toUtf8();
+    SmPropValue prop;
+    prop.length = v.length();
+    prop.value = (SmPointer) v.constData();
+    sm_setProperty(name.toLatin1().data(), SmARRAY8, 1, &prop);
+}
+
+static void sm_setProperty(const QString &name, const QStringList &value)
+{
+    SmPropValue *prop = new SmPropValue[value.count()];
+    int count = 0;
+    QList<QByteArray> vl;
+    for (QStringList::ConstIterator it = value.begin(); it != value.end(); ++it) {
+      prop[count].length = (*it).length();
+      vl.append((*it).toUtf8());
+      prop[count].value = (char*)vl.last().data();
+      ++count;
+    }
+    sm_setProperty(name.toLatin1().data(), SmLISTofARRAY8, count, prop);
+    delete [] prop;
+}
+
+
+// workaround for broken libsm, see below
+struct QT_smcConn {
+    unsigned int save_yourself_in_progress : 1;
+    unsigned int shutdown_in_progress : 1;
+};
+
+static void sm_saveYourselfCallback(SmcConn smcConn, SmPointer clientData,
+                                  int saveType, Bool shutdown , int interactStyle, Bool /*fast*/)
+{
+    if (smcConn != smcConnection)
+        return;
+    sm_cancel = false;
+    sm_smActive = true;
+    sm_isshutdown = shutdown;
+    sm_saveType = saveType;
+    sm_interactStyle = interactStyle;
+
+    // ugly workaround for broken libSM. libSM should do that _before_
+    // actually invoking the callback in sm_process.c
+    ((QT_smcConn*)smcConn)->save_yourself_in_progress = true;
+    if (sm_isshutdown)
+        ((QT_smcConn*)smcConn)->shutdown_in_progress = true;
+
+    sm_performSaveYourself((QXcbSessionManager*) clientData);
+    if (!sm_isshutdown) // we cannot expect a confirmation message in that case
+        resetSmState();
+}
+
+static void sm_performSaveYourself(QXcbSessionManager *sm)
+{
+    if (sm_isshutdown)
+        qt_sm_blockUserInput = true;
+
+    // generate a new session key
+    timeval tv;
+    gettimeofday(&tv, 0);
+    sm->setSessionKey(QString::number(qulonglong(tv.tv_sec)) +
+                      QLatin1Char('_') +
+                      QString::number(qulonglong(tv.tv_usec)));
+
+    QStringList arguments = QCoreApplication::arguments();
+    QString argument0 = arguments.isEmpty() ? QCoreApplication::applicationFilePath()
+                                            : arguments.at(0);
+
+    // tell the session manager about our program in best POSIX style
+    sm_setProperty(QString::fromLatin1(SmProgram), argument0);
+    // tell the session manager about our user as well.
+    struct passwd *entryPtr = 0;
+#if defined(_POSIX_THREAD_SAFE_FUNCTIONS) && (_POSIX_THREAD_SAFE_FUNCTIONS - 0 > 0)
+    QVarLengthArray<char, 1024> buf(qMax<long>(sysconf(_SC_GETPW_R_SIZE_MAX), 1024L));
+    struct passwd entry;
+    while (getpwuid_r(geteuid(), &entry, buf.data(), buf.size(), &entryPtr) == ERANGE) {
+        if (buf.size() >= 32768) {
+            // too big already, fail
+            static char badusername[] = "";
+            entryPtr = &entry;
+            entry.pw_name = badusername;
+            break;
+        }
+
+        // retry with a bigger buffer
+        buf.resize(buf.size() * 2);
+    }
+#else
+    entryPtr = getpwuid(geteuid());
+#endif
+    if (entryPtr)
+        sm_setProperty(QString::fromLatin1(SmUserID), QString::fromLocal8Bit(entryPtr->pw_name));
+
+    // generate a restart and discard command that makes sense
+    QStringList restart;
+    restart  << argument0 << QLatin1String("-session")
+             << sm->sessionId() + QLatin1Char('_') + sm->sessionKey();
+
+    QFileInfo fi = QCoreApplication::applicationFilePath();
+    if (qAppName().compare(fi.fileName(), Qt::CaseInsensitive) != 0)
+        restart << QLatin1String("-name") << qAppName();
+    sm->setRestartCommand(restart);
+    QStringList discard;
+    sm->setDiscardCommand(discard);
+
+    switch (sm_saveType) {
+    case SmSaveBoth:
+        sm->appCommitData();
+        if (sm_isshutdown && sm_cancel)
+            break; // we cancelled the shutdown, no need to save state
+    // fall through
+    case SmSaveLocal:
+        sm->appSaveState();
+        break;
+    case SmSaveGlobal:
+        sm->appCommitData();
+        break;
+    default:
+        break;
+    }
+
+    if (sm_phase2 && !sm_in_phase2) {
+        SmcRequestSaveYourselfPhase2(smcConnection, sm_saveYourselfPhase2Callback, (SmPointer*) sm);
+        qt_sm_blockUserInput = false;
+    } else {
+        // close eventual interaction monitors and cancel the
+        // shutdown, if required. Note that we can only cancel when
+        // performing a shutdown, it does not work for checkpoints
+        if (sm_interactionActive) {
+            SmcInteractDone(smcConnection, sm_isshutdown && sm_cancel);
+            sm_interactionActive = false;
+        } else if (sm_cancel && sm_isshutdown) {
+            if (sm->allowsErrorInteraction()) {
+                SmcInteractDone(smcConnection, True);
+                sm_interactionActive = false;
+            }
+        }
+
+        // set restart and discard command in session manager
+        sm_setProperty(QString::fromLatin1(SmRestartCommand), sm->restartCommand());
+        sm_setProperty(QString::fromLatin1(SmDiscardCommand), sm->discardCommand());
+
+        // set the restart hint
+        SmPropValue prop;
+        prop.length = sizeof(int);
+        int value = sm->restartHint();
+        prop.value = (SmPointer) &value;
+        sm_setProperty(SmRestartStyleHint, SmCARD8, 1, &prop);
+
+        // we are done
+        SmcSaveYourselfDone(smcConnection, !sm_cancel);
+    }
+}
+
+static void sm_dieCallback(SmcConn smcConn, SmPointer /* clientData */)
+{
+    if (smcConn != smcConnection)
+        return;
+    resetSmState();
+    QEvent quitEvent(QEvent::Quit);
+    QGuiApplication::sendEvent(qApp, &quitEvent);
+}
+
+static void sm_shutdownCancelledCallback(SmcConn smcConn, SmPointer clientData)
+{
+    if (smcConn != smcConnection)
+        return;
+    if (sm_waitingForInteraction)
+        ((QXcbSessionManager *) clientData)->exitEventLoop();
+    resetSmState();
+}
+
+static void sm_saveCompleteCallback(SmcConn smcConn, SmPointer /*clientData */)
+{
+    if (smcConn != smcConnection)
+        return;
+    resetSmState();
+}
+
+static void sm_interactCallback(SmcConn smcConn, SmPointer clientData)
+{
+    if (smcConn != smcConnection)
+        return;
+    if (sm_waitingForInteraction)
+        ((QXcbSessionManager *) clientData)->exitEventLoop();
+}
+
+static void sm_saveYourselfPhase2Callback(SmcConn smcConn, SmPointer clientData)
+{
+    if (smcConn != smcConnection)
+        return;
+    sm_in_phase2 = true;
+    sm_performSaveYourself((QXcbSessionManager *) clientData);
+}
+
+
+void QSmSocketReceiver::socketActivated(int)
+{
+    IceProcessMessages(SmcGetIceConnection(smcConnection), 0, 0);
+}
+
+
+// QXcbSessionManager starts here
+
+QXcbSessionManager::QXcbSessionManager(const QString &id, const QString &key)
+    : QPlatformSessionManager(id, key)
+    , m_eventLoop(0)
+{
+    resetSmState();
+    char cerror[256];
+    char* myId = 0;
+    QByteArray b_id = id.toLatin1();
+    char* prevId = b_id.data();
+
+    SmcCallbacks cb;
+    cb.save_yourself.callback = sm_saveYourselfCallback;
+    cb.save_yourself.client_data = (SmPointer) this;
+    cb.die.callback = sm_dieCallback;
+    cb.die.client_data = (SmPointer) this;
+    cb.save_complete.callback = sm_saveCompleteCallback;
+    cb.save_complete.client_data = (SmPointer) this;
+    cb.shutdown_cancelled.callback = sm_shutdownCancelledCallback;
+    cb.shutdown_cancelled.client_data = (SmPointer) this;
+
+    // avoid showing a warning message below
+    if (!qEnvironmentVariableIsSet("SESSION_MANAGER"))
+        return;
+
+    smcConnection = SmcOpenConnection(0, 0, 1, 0,
+                                      SmcSaveYourselfProcMask |
+                                      SmcDieProcMask |
+                                      SmcSaveCompleteProcMask |
+                                      SmcShutdownCancelledProcMask,
+                                      &cb,
+                                      prevId,
+                                      &myId,
+                                      256, cerror);
+
+    setSessionId(QString::fromLatin1(myId));
+    ::free(myId); // it was allocated by C
+
+    QString error = QString::fromLocal8Bit(cerror);
+    if (!smcConnection)
+        qWarning("Qt: Session management error: %s", qPrintable(error));
+    else
+        sm_receiver = new QSmSocketReceiver(IceConnectionNumber(SmcGetIceConnection(smcConnection)));
+}
+
+QXcbSessionManager::~QXcbSessionManager()
+{
+    if (smcConnection)
+        SmcCloseConnection(smcConnection, 0, 0);
+    smcConnection = 0;
+    delete sm_receiver;
+}
+
+
+void* QXcbSessionManager::handle() const
+{
+    return (void*) smcConnection;
+}
+
+void QXcbSessionManager::setSessionId(const QString &id)
+{
+    m_sessionId = id;
+}
+
+void QXcbSessionManager::setSessionKey(const QString &key)
+{
+    m_sessionKey = key;
+}
+
+bool QXcbSessionManager::allowsInteraction()
+{
+    if (sm_interactionActive)
+        return true;
+
+    if (sm_waitingForInteraction)
+        return false;
+
+    if (sm_interactStyle == SmInteractStyleAny) {
+        sm_waitingForInteraction = SmcInteractRequest(smcConnection,
+                                                      SmDialogNormal,
+                                                      sm_interactCallback,
+                                                      (SmPointer*) this);
+    }
+    if (sm_waitingForInteraction) {
+        QEventLoop eventLoop;
+        m_eventLoop = &eventLoop;
+        eventLoop.exec();
+        m_eventLoop = 0;
+
+        sm_waitingForInteraction = false;
+        if (sm_smActive) { // not cancelled
+            sm_interactionActive = true;
+            qt_sm_blockUserInput = false;
+            return true;
+        }
+    }
+    return false;
+}
+
+bool QXcbSessionManager::allowsErrorInteraction()
+{
+    if (sm_interactionActive)
+        return true;
+
+    if (sm_waitingForInteraction)
+        return false;
+
+    if (sm_interactStyle == SmInteractStyleAny || sm_interactStyle == SmInteractStyleErrors) {
+        sm_waitingForInteraction = SmcInteractRequest(smcConnection,
+                                                      SmDialogError,
+                                                      sm_interactCallback,
+                                                      (SmPointer*) this);
+    }
+    if (sm_waitingForInteraction) {
+        QEventLoop eventLoop;
+        m_eventLoop = &eventLoop;
+        eventLoop.exec();
+        m_eventLoop = 0;
+
+        sm_waitingForInteraction = false;
+        if (sm_smActive) { // not cancelled
+            sm_interactionActive = true;
+            qt_sm_blockUserInput = false;
+            return true;
+        }
+    }
+    return false;
+}
+
+void QXcbSessionManager::release()
+{
+    if (sm_interactionActive) {
+        SmcInteractDone(smcConnection, False);
+        sm_interactionActive = false;
+        if (sm_smActive && sm_isshutdown)
+            qt_sm_blockUserInput = true;
+    }
+}
+
+void QXcbSessionManager::cancel()
+{
+    sm_cancel = true;
+}
+
+void QXcbSessionManager::setManagerProperty(const QString &name, const QString &value)
+{
+    sm_setProperty(name, value);
+}
+
+void QXcbSessionManager::setManagerProperty(const QString &name, const QStringList &value)
+{
+    sm_setProperty(name, value);
+}
+
+bool QXcbSessionManager::isPhase2() const
+{
+    return sm_in_phase2;
+}
+
+void QXcbSessionManager::requestPhase2()
+{
+    sm_phase2 = true;
+}
+
+void QXcbSessionManager::appCommitData()
+{
+    QPlatformSessionManager::appCommitData();
+}
+
+void QXcbSessionManager::appSaveState()
+{
+    QPlatformSessionManager::appSaveState();
+}
+
+void QXcbSessionManager::exitEventLoop()
+{
+    m_eventLoop->exit();
+}
+
+#include "qxcbsessionmanager.moc"
diff --git a/src/plugins/platforms/xcb/qxcbsessionmanager.h b/src/plugins/platforms/xcb/qxcbsessionmanager.h
new file mode 100644
index 0000000000..0dca36d16f
--- /dev/null
+++ b/src/plugins/platforms/xcb/qxcbsessionmanager.h
@@ -0,0 +1,88 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Teo Mrnjavac <teo@kde.org>
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QXCBSESSIONMANAGER_H
+#define QXCBSESSIONMANAGER_H
+
+#include <qpa/qplatformsessionmanager.h>
+
+QT_BEGIN_NAMESPACE
+
+class QEventLoop;
+
+class QXcbSessionManager : public QPlatformSessionManager
+{
+public:
+    QXcbSessionManager(const QString &id, const QString &key);
+    virtual ~QXcbSessionManager();
+
+    void *handle() const;
+
+    void setSessionId(const QString &id);
+    void setSessionKey(const QString &key);
+
+    bool allowsInteraction() Q_DECL_OVERRIDE;
+    bool allowsErrorInteraction() Q_DECL_OVERRIDE;
+    void release() Q_DECL_OVERRIDE;
+
+    void cancel() Q_DECL_OVERRIDE;
+
+    void setManagerProperty(const QString &name, const QString &value) Q_DECL_OVERRIDE;
+    void setManagerProperty(const QString &name, const QStringList &value) Q_DECL_OVERRIDE;
+
+    bool isPhase2() const Q_DECL_OVERRIDE;
+    void requestPhase2() Q_DECL_OVERRIDE;
+
+    void appCommitData() Q_DECL_OVERRIDE;
+    void appSaveState() Q_DECL_OVERRIDE;
+
+    void exitEventLoop();
+
+private:
+    QEventLoop *m_eventLoop;
+
+    Q_DISABLE_COPY(QXcbSessionManager)
+};
+
+QT_END_NAMESPACE
+
+#endif //QXCBSESSIONMANAGER_H
diff --git a/src/plugins/platforms/xcb/xcb-plugin.pro b/src/plugins/platforms/xcb/xcb-plugin.pro
index b198ab1717..fa1dc12eb5 100644
--- a/src/plugins/platforms/xcb/xcb-plugin.pro
+++ b/src/plugins/platforms/xcb/xcb-plugin.pro
@@ -72,6 +72,13 @@ contains(QT_CONFIG, xcb-render) {
     LIBS += -lxcb-render -lxcb-render-util -lXrender
 }
 
+# build with session management support
+contains(QT_CONFIG, xcb-sm) {
+    LIBS += -lSM -lICE
+    SOURCES += qxcbsessionmanager.cpp
+    HEADERS += qxcbsessionmanager.h
+}
+
 contains(QT_CONFIG, opengl) {
     contains(QT_CONFIG, opengles2) {
         DEFINES += XCB_USE_EGL