QLocalSocket/Win: prevent writing to broken pipe

When a peer closes the connection, the device remains opened for reading
purposes. However, we should disable writing on disconnected socket.
Otherwise, if the user issues a write() call, a new pipe writer object
will be created and the write call occurs with invalid handle value.

Change-Id: Id136798c7663df1fce7ed0aa4e3c6f5c65218a11
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
(cherry picked from commit 53b4556332e95820622742e9be16281a77f9d337)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/network/socket/qlocalsocket_win.cpp b/src/network/socket/qlocalsocket_win.cpp
index 48ffd87beb..6d82656583 100644
--- a/src/network/socket/qlocalsocket_win.cpp
+++ b/src/network/socket/qlocalsocket_win.cpp
@@ -207,6 +207,12 @@ qint64 QLocalSocket::readData(char *data, qint64 maxSize)
 qint64 QLocalSocket::writeData(const char *data, qint64 len)
 {
     Q_D(QLocalSocket);
+    if (!isValid()) {
+        d->error = OperationError;
+        d->errorString = tr("Socket is not connected");
+        return -1;
+    }
+
     if (len == 0)
         return 0;
     d->writeBuffer.append(data, len);