Fix bind+connect in both TCP and UDP

This has been known to be broken for a while. Now it works: you can bind
and you'll retain the port (and the file descriptor) for the connect
call. Incidentally, in fixing the binding for more than one IP for the
hostname (with event loop), this commit fixes the setSocketDescriptor
XFAIL.

[ChangeLog][QtNetwork] Fixed a bug that caused both QTcpSocket and
QUdpSocket to close the socket and lose any bound ports before
connecting. Now bind()/setSocketDescriptor() followed by connect() will
retain the original file descriptor.

Task-number: QTBUG-26538
Change-Id: I691caed7e8fd16a9cf687b5995afbf3006bf453a
Reviewed-by: Richard J. Moore <rich@kde.org>

1 files changed, 36 insertions, 31 deletions

diff --git a/src/network/socket/qabstractsocket.cpp b/src/network/socket/qabstractsocket.cpp
index f9fe40955a..3b10387b37 100644
--- a/src/network/socket/qabstractsocket.cpp
+++ b/src/network/socket/qabstractsocket.cpp
@@ -976,7 +976,7 @@ void QAbstractSocketPrivate::startConnectingByName(const QString &host)
 
     connectTimeElapsed = 0;
 
-    if (initSocketLayer(QAbstractSocket::UnknownNetworkLayerProtocol)) {
+    if (cachedSocketDescriptor != -1 || initSocketLayer(QAbstractSocket::UnknownNetworkLayerProtocol)) {
         if (socketEngine->connectToHostByName(host, port) ||
             socketEngine->state() == QAbstractSocket::ConnectingState) {
             cachedSocketDescriptor = socketEngine->socketDescriptor();
@@ -1117,7 +1117,7 @@ void QAbstractSocketPrivate::_q_connectToNextAddress()
                host.toString().toLatin1().constData(), port, addresses.count());
 #endif
 
-        if (!initSocketLayer(host.protocol())) {
+        if (cachedSocketDescriptor == -1 && !initSocketLayer(host.protocol())) {
             // hope that the next address is better
 #if defined(QABSTRACTSOCKET_DEBUG)
             qDebug("QAbstractSocketPrivate::_q_connectToNextAddress(), failed to initialize sock layer");
@@ -1134,9 +1134,6 @@ void QAbstractSocketPrivate::_q_connectToNextAddress()
             return;
         }
 
-        // cache the socket descriptor even if we're not fully connected yet
-        cachedSocketDescriptor = socketEngine->socketDescriptor();
-
         // Check that we're in delayed connection state. If not, try
         // the next address
         if (socketEngine->state() != QAbstractSocket::ConnectingState) {
@@ -1481,54 +1478,60 @@ void QAbstractSocket::setPauseMode(PauseModes pauseMode)
 bool QAbstractSocket::bind(const QHostAddress &address, quint16 port, BindMode mode)
 {
     Q_D(QAbstractSocket);
+    return d->bind(address, port, mode);
+}
+
+bool QAbstractSocketPrivate::bind(const QHostAddress &address, quint16 port, QAbstractSocket::BindMode mode)
+{
+    Q_Q(QAbstractSocket);
 
     // now check if the socket engine is initialized and to the right type
-    if (!d->socketEngine || !d->socketEngine->isValid()) {
+    if (!socketEngine || !socketEngine->isValid()) {
         QHostAddress nullAddress;
-        d->resolveProxy(nullAddress.toString(), port);
+        resolveProxy(nullAddress.toString(), port);
 
         QAbstractSocket::NetworkLayerProtocol protocol = address.protocol();
         if (protocol == QAbstractSocket::UnknownNetworkLayerProtocol)
             protocol = nullAddress.protocol();
 
-        if (!d->initSocketLayer(protocol))
+        if (!initSocketLayer(protocol))
             return false;
     }
 
-    if (mode != DefaultForPlatform) {
+    if (mode != QAbstractSocket::DefaultForPlatform) {
 #ifdef Q_OS_UNIX
-    if ((mode & ShareAddress) || (mode & ReuseAddressHint))
-        d->socketEngine->setOption(QAbstractSocketEngine::AddressReusable, 1);
+    if ((mode & QAbstractSocket::ShareAddress) || (mode & QAbstractSocket::ReuseAddressHint))
+        socketEngine->setOption(QAbstractSocketEngine::AddressReusable, 1);
     else
-        d->socketEngine->setOption(QAbstractSocketEngine::AddressReusable, 0);
+        socketEngine->setOption(QAbstractSocketEngine::AddressReusable, 0);
 #endif
 #ifdef Q_OS_WIN
-    if (mode & ReuseAddressHint)
-        d->socketEngine->setOption(QAbstractSocketEngine::AddressReusable, 1);
+    if (mode & QAbstractSocket::ReuseAddressHint)
+        socketEngine->setOption(QAbstractSocketEngine::AddressReusable, 1);
     else
-        d->socketEngine->setOption(QAbstractSocketEngine::AddressReusable, 0);
-    if (mode & DontShareAddress)
-        d->socketEngine->setOption(QAbstractSocketEngine::BindExclusively, 1);
+        socketEngine->setOption(QAbstractSocketEngine::AddressReusable, 0);
+    if (mode & QAbstractSocket::DontShareAddress)
+        socketEngine->setOption(QAbstractSocketEngine::BindExclusively, 1);
     else
-        d->socketEngine->setOption(QAbstractSocketEngine::BindExclusively, 0);
+        socketEngine->setOption(QAbstractSocketEngine::BindExclusively, 0);
 #endif
     }
-    bool result = d->socketEngine->bind(address, port);
-    d->cachedSocketDescriptor = d->socketEngine->socketDescriptor();
+    bool result = socketEngine->bind(address, port);
+    cachedSocketDescriptor = socketEngine->socketDescriptor();
 
     if (!result) {
-        d->socketError = d->socketEngine->error();
-        setErrorString(d->socketEngine->errorString());
-        emit error(d->socketError);
+        socketError = socketEngine->error();
+        q->setErrorString(socketEngine->errorString());
+        emit q->error(socketError);
         return false;
     }
 
-    d->state = BoundState;
-    d->localAddress = d->socketEngine->localAddress();
-    d->localPort = d->socketEngine->localPort();
+    state = QAbstractSocket::BoundState;
+    localAddress = socketEngine->localAddress();
+    localPort = socketEngine->localPort();
 
-    emit stateChanged(d->state);
-    d->socketEngine->setReadNotificationEnabled(true);
+    emit q->stateChanged(state);
+    socketEngine->setReadNotificationEnabled(true);
     return true;
 }
 
@@ -1605,14 +1608,16 @@ void QAbstractSocket::connectToHost(const QString &hostName, quint16 port,
     d->preferredNetworkLayerProtocol = protocol;
     d->hostName = hostName;
     d->port = port;
-    d->state = UnconnectedState;
     d->buffer.clear();
     d->writeBuffer.clear();
     d->abortCalled = false;
     d->pendingClose = false;
-    d->localPort = 0;
+    if (d->state != BoundState) {
+        d->state = UnconnectedState;
+        d->localPort = 0;
+        d->localAddress.clear();
+    }
     d->peerPort = 0;
-    d->localAddress.clear();
     d->peerAddress.clear();
     d->peerName = hostName;
     if (d->hostLookupId != -1) {