Return an invalid QSqlDatabase when accessing from another thread

QSqlDatabase objects can only be used in the thread that the connection
was opened for. So if the driver was created already then we check if
the thread is correct. If it is not then we output a warning and return
an invalid QSqlDatabase.

[ChangeLog][QtSql][QSqlDatabase] QSqlDatabase::database() will return
an invalid QSqlDatabase if the calling thread does not own the requested
QSqlDatabase.

Task-number: QTBUG-216
Change-Id: Ib5a25aa62129e3925f9819109af05961e5178bc5
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/sql/kernel/qsqldatabase.cpp b/src/sql/kernel/qsqldatabase.cpp
index b129499fe6..ded9bd7246 100644
--- a/src/sql/kernel/qsqldatabase.cpp
+++ b/src/sql/kernel/qsqldatabase.cpp
@@ -50,6 +50,7 @@
 #include "private/qsqlnulldriver_p.h"
 #include "qmutex.h"
 #include "qhash.h"
+#include "qthread.h"
 #include <stdlib.h>
 
 QT_BEGIN_NAMESPACE
@@ -232,6 +233,11 @@ QSqlDatabase QSqlDatabasePrivate::database(const QString& name, bool open)
     dict->lock.lockForRead();
     QSqlDatabase db = dict->value(name);
     dict->lock.unlock();
+    if (db.driver() && db.driver()->thread() != QThread::currentThread()) {
+        qWarning("QSqlDatabasePrivate::database: requested database does not belong to the calling thread.");
+        return QSqlDatabase();
+    }
+
     if (db.isValid() && !db.isOpen() && open) {
         if (!db.open())
             qWarning() << "QSqlDatabasePrivate::database: unable to open database:" << db.lastError().text();