From 7d7a04033597364708118443baa3344c184da1d8 Mon Sep 17 00:00:00 2001
From: Callum McIntyre <callumiandavid.mcintyre@citrix.com>
Date: Mon, 24 Oct 2016 11:59:28 +0100
Subject: [PATCH] [CA-211267] Add a null check, use Run() to stop child classes
 directly calling InitialiseTicker()

TickUntilCompletion() is now a static method and again takes an ApplianceAction parameter. It does a null check on each while iteration to handle the case where another thread nulls the action. Also added Run() method to ApplianceAction which initialises the ticker (now a private method), and let child classes call Run() instead.
---
 XenAdmin/Actions/OVFActions/ApplianceAction.cs   | 16 +++++++++++-----
 .../Actions/OVFActions/ExportApplianceAction.cs  |  5 ++---
 .../Actions/OVFActions/ImportApplianceAction.cs  |  4 +---
 XenAdmin/Actions/OVFActions/ImportImageAction.cs |  5 ++---
 4 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/XenAdmin/Actions/OVFActions/ApplianceAction.cs b/XenAdmin/Actions/OVFActions/ApplianceAction.cs
index 3b4172822..23775355e 100644
--- a/XenAdmin/Actions/OVFActions/ApplianceAction.cs
+++ b/XenAdmin/Actions/OVFActions/ApplianceAction.cs
@@ -82,6 +82,12 @@ namespace XenAdmin.Actions.OVFActions
 				Host = Helpers.GetMaster(connection);
 		}
 
+	    protected override void Run()
+	    {
+	        SafeToExit = false; 
+            InitialiseTicker();
+	    }
+
 		protected void UpdateHandler(XenOvfTranportEventArgs e)
 		{
 			if (!string.IsNullOrEmpty(e.Message))
@@ -101,16 +107,16 @@ namespace XenAdmin.Actions.OVFActions
 				m_transportAction.Cancel = true;
 		}
 
-	    protected void InitialiseTicker()
+	    private void InitialiseTicker()
 	    {
-	        System.Threading.Tasks.Task.Run(() => TickUntilCompletion());
+	        System.Threading.Tasks.Task.Run(() => TickUntilCompletion(this));
 	    }
 
-	    private void TickUntilCompletion()
+	    private static  void TickUntilCompletion(ApplianceAction action)
 	    {
-	        while (!IsCompleted)
+	        while (action != null && !action.IsCompleted)
 	        {
-	            OnChanged();
+	            action.OnChanged();
                 Thread.Sleep(SLEEP_TIME);
 	        }
 	    }
diff --git a/XenAdmin/Actions/OVFActions/ExportApplianceAction.cs b/XenAdmin/Actions/OVFActions/ExportApplianceAction.cs
index cfcea029f..6073d64e4 100644
--- a/XenAdmin/Actions/OVFActions/ExportApplianceAction.cs
+++ b/XenAdmin/Actions/OVFActions/ExportApplianceAction.cs
@@ -90,11 +90,10 @@ namespace XenAdmin.Actions.OVFActions
 
 		protected override void Run()
 		{
-		    SafeToExit = false;
+            base.Run();
+		    
 			var session = Connection.Session;
 
-            InitialiseTicker();
-
 			var url = session.Url;
 			Uri uri = new Uri(url);
 
diff --git a/XenAdmin/Actions/OVFActions/ImportApplianceAction.cs b/XenAdmin/Actions/OVFActions/ImportApplianceAction.cs
index 350adfacd..52e52a99f 100644
--- a/XenAdmin/Actions/OVFActions/ImportApplianceAction.cs
+++ b/XenAdmin/Actions/OVFActions/ImportApplianceAction.cs
@@ -76,9 +76,7 @@ namespace XenAdmin.Actions.OVFActions
 
 		protected override void Run()
 		{
-		    SafeToExit = false;
-            
-            InitialiseTicker();
+		    base.Run();
 
 			if (m_verifySignature)
 			{
diff --git a/XenAdmin/Actions/OVFActions/ImportImageAction.cs b/XenAdmin/Actions/OVFActions/ImportImageAction.cs
index d270d085c..ce7c11582 100644
--- a/XenAdmin/Actions/OVFActions/ImportImageAction.cs
+++ b/XenAdmin/Actions/OVFActions/ImportImageAction.cs
@@ -70,10 +70,9 @@ namespace XenAdmin.Actions.OVFActions
 
 		protected override void Run()
 		{
-		    SafeToExit = false;
-			Debug.Assert(m_vmMappings.Count == 1, "There is one VM mapping");
+		    base.Run();
 
-            InitialiseTicker();
+			Debug.Assert(m_vmMappings.Count == 1, "There is one VM mapping");
 
 			string systemid = m_vmMappings.Keys.ElementAt(0);
 			var mapping = m_vmMappings.Values.ElementAt(0);