From 7b14c47d6adbc6ab3cdfc9d10bef25029215a85f Mon Sep 17 00:00:00 2001
From: Gatis Paeglis <gatis.paeglis@theqtcompany.com>
Date: Tue, 17 Feb 2015 17:39:14 +0100
Subject: Prevent reading wifi events from closed connection

Stop wifi event thread before closing down a connection
to wpa-supplicant to avoid race-condition where we can
end up reading events from closed socket and blocking
the new connection from attaching to the socket.

Change-Id: Ie1efabf35791e0dac3f57fa8038b0e414cbff1f5
Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>
---
 src/wifi/qwificontroller.cpp | 10 +++++-----
 src/wifi/qwificontroller_p.h |  2 +-
 src/wifi/qwifimanager.cpp    |  4 +---
 3 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/src/wifi/qwificontroller.cpp b/src/wifi/qwificontroller.cpp
index 216c70c..7b8be80 100644
--- a/src/wifi/qwificontroller.cpp
+++ b/src/wifi/qwificontroller.cpp
@@ -278,7 +278,6 @@ void QWifiController::initializeBackend()
     }
 #endif
     if (!initFailed && resetSupplicantSocket()) {
-        startWifiEventThread();
         qCDebug(B2QT_WIFI) << "wifi backend started successfully";
         emit backendStateChanged(QWifiManager::Running);
     } else {
@@ -286,11 +285,10 @@ void QWifiController::initializeBackend()
     }
 }
 
-bool QWifiController::resetSupplicantSocket() const
+bool QWifiController::resetSupplicantSocket()
 {
     qCDebug(B2QT_WIFI) << "reset supplicant socket";
-    // close down the previous connection to supplicant if
-    // one exists before re-connecting.
+    exitWifiEventThread();
     if (q_wifi_stop_supplicant() < 0)
         qCWarning(B2QT_WIFI) << "failed to stop supplicant!";
     q_wifi_close_supplicant_connection(m_interface);
@@ -310,6 +308,7 @@ bool QWifiController::resetSupplicantSocket() const
         qCWarning(B2QT_WIFI) << "failed to connect to a supplicant!";
         return false;
     }
+    startWifiEventThread();
     return true;
 }
 
@@ -345,7 +344,8 @@ void QWifiController::exitWifiEventThread()
     if (m_eventThread->isRunning()) {
         m_exitEventThread = true;
         m_managerPrivate->call(QStringLiteral("SCAN"));
-        m_eventThread->wait();
+        if (!m_eventThread->wait(8000))
+            qCWarning(B2QT_WIFI, "timed out waiting for wifi event thread to exit!");
     }
 }
 
diff --git a/src/wifi/qwificontroller_p.h b/src/wifi/qwificontroller_p.h
index 63ad2ef..185cff9 100644
--- a/src/wifi/qwificontroller_p.h
+++ b/src/wifi/qwificontroller_p.h
@@ -97,7 +97,7 @@ public:
     void startWifiEventThread();
     void acquireIPAddress();
     void stopDhcp() const;
-    bool resetSupplicantSocket() const;
+    bool resetSupplicantSocket();
 
 signals:
     void backendStateChanged(QWifiManager::BackendState backendState);
diff --git a/src/wifi/qwifimanager.cpp b/src/wifi/qwifimanager.cpp
index 14d839e..7585cf2 100644
--- a/src/wifi/qwifimanager.cpp
+++ b/src/wifi/qwifimanager.cpp
@@ -123,10 +123,8 @@ void QWifiManagerPrivate::updateWifiState()
     if (ps.readAll().contains("wpa_supplicant"))
         supplicantRunning = true;
 #endif
-    if (supplicantRunning && m_wifiController->resetSupplicantSocket()) {
-        m_wifiController->startWifiEventThread();
+    if (supplicantRunning && m_wifiController->resetSupplicantSocket())
         m_backendState = QWifiManager::Running;
-    }
 }
 
 QString QWifiManagerPrivate::call(const QString &command)
-- 
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