From 72700167cf051e5053f03bf4f4be391cd7514502 Mon Sep 17 00:00:00 2001

From: Thiago Macieira <thiago.macieira@intel.com>

Date: Tue, 31 May 2016 17:33:03 -0300

Subject: [PATCH 2/2] Fix some QtDBus crashes during application destruction

It's possible that some code executes after QDBusConnectionManager is

destroyed and still tries to access QtDBus. Protect against such

crashes.

Change-Id: I87e17314d8b24ae983b1fffd1453c13fbd3cf48e

---

 src/dbus/qdbusconnection.cpp | 12 ++++++++----

 src/dbus/qdbusintegrator.cpp |  3 +++

 src/dbus/qdbusserver.cpp     | 12 ++++++++++--

 3 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/src/dbus/qdbusconnection.cpp b/src/dbus/qdbusconnection.cpp

index 4187f19..aa14ac2 100644

--- a/src/dbus/qdbusconnection.cpp

+++ b/src/dbus/qdbusconnection.cpp

@@ -418,7 +418,7 @@ void QDBusConnectionManager::createServer(const QString &address, void *server)

 */

 QDBusConnection::QDBusConnection(const QString &name)

 {

-    if (name.isEmpty()) {

+    if (name.isEmpty() || _q_manager.isDestroyed()) {

         d = 0;

     } else {

         QMutexLocker locker(&_q_manager()->mutex);

@@ -483,7 +483,7 @@ QDBusConnection &QDBusConnection::operator=(const QDBusConnection &other)

 */

 QDBusConnection QDBusConnection::connectToBus(BusType type, const QString &name)

 {

-    if (!qdbus_loadLibDBus()) {

+    if (_q_manager.isDestroyed() || !qdbus_loadLibDBus()) {

         QDBusConnectionPrivate *d = 0;

         return QDBusConnection(d);

     }

@@ -497,7 +497,7 @@ QDBusConnection QDBusConnection::connectToBus(BusType type, const QString &name)

 QDBusConnection QDBusConnection::connectToBus(const QString &address,

                                               const QString &name)

 {

-    if (!qdbus_loadLibDBus()) {

+    if (_q_manager.isDestroyed() || !qdbus_loadLibDBus()) {

         QDBusConnectionPrivate *d = 0;

         return QDBusConnection(d);

     }

@@ -512,7 +512,7 @@ QDBusConnection QDBusConnection::connectToBus(const QString &address,

 QDBusConnection QDBusConnection::connectToPeer(const QString &address,

                                                const QString &name)

 {

-    if (!qdbus_loadLibDBus()) {

+    if (_q_manager.isDestroyed() || !qdbus_loadLibDBus()) {

         QDBusConnectionPrivate *d = 0;

         return QDBusConnection(d);

     }

@@ -1167,6 +1167,8 @@ bool QDBusConnection::unregisterService(const QString &serviceName)

 */

 QDBusConnection QDBusConnection::sessionBus()

 {

+    if (_q_manager.isDestroyed())

+        return QDBusConnection(Q_NULLPTR);

     return QDBusConnection(_q_manager()->busConnection(SessionBus));

 }

@@ -1179,6 +1181,8 @@ QDBusConnection QDBusConnection::sessionBus()

 */

 QDBusConnection QDBusConnection::systemBus()

 {

+    if (_q_manager.isDestroyed())

+        return QDBusConnection(Q_NULLPTR);

     return QDBusConnection(_q_manager()->busConnection(SystemBus));

 }

diff --git a/src/dbus/qdbusintegrator.cpp b/src/dbus/qdbusintegrator.cpp

index 19f79e9..f8dc702 100644

--- a/src/dbus/qdbusintegrator.cpp

+++ b/src/dbus/qdbusintegrator.cpp

@@ -299,6 +299,9 @@ static void qDBusNewConnection(DBusServer *server, DBusConnection *connection, v

     Q_ASSERT(connection);

     Q_ASSERT(data);

+    if (!QDBusConnectionManager::instance())

+        return;

+

     // keep the connection alive

     q_dbus_connection_ref(connection);

     QDBusConnectionPrivate *serverConnection = static_cast<QDBusConnectionPrivate *>(data);

diff --git a/src/dbus/qdbusserver.cpp b/src/dbus/qdbusserver.cpp

index 027ce93..b1f9be2 100644

--- a/src/dbus/qdbusserver.cpp

+++ b/src/dbus/qdbusserver.cpp

@@ -68,7 +68,11 @@ QDBusServer::QDBusServer(const QString &address, QObject *parent)

     if (!qdbus_loadLibDBus())

         return;

-    emit QDBusConnectionManager::instance()->serverRequested(address, this);

+    QDBusConnectionManager *instance = QDBusConnectionManager::instance();

+    if (!instance)

+        return;

+

+    emit instance->serverRequested(address, this);

     QObject::connect(d, SIGNAL(newServerConnection(QDBusConnectionPrivate*)),

                      this, SLOT(_q_newConnection(QDBusConnectionPrivate*)), Qt::QueuedConnection);

 }

@@ -93,7 +97,11 @@ QDBusServer::QDBusServer(QObject *parent)

         return;

     }

-    emit QDBusConnectionManager::instance()->serverRequested(address, this);

+    QDBusConnectionManager *instance = QDBusConnectionManager::instance();

+    if (!instance)

+        return;

+

+    emit instance->serverRequested(address, this);

     QObject::connect(d, SIGNAL(newServerConnection(QDBusConnectionPrivate*)),

                      this, SLOT(_q_newConnection(QDBusConnectionPrivate*)), Qt::QueuedConnection);

 }

-- 

2.9.3