/// <summary>
/// This function attempts to find out if there is currently a node running
/// for a given index. The node is running if the global mutex with a
/// "Node_" + nodeId + "_ActiveReady" as a name was created
/// </summary>
private static bool checkIfNodeActive(int nodeNumber)
{
bool nodeIsActive = false;
EventWaitHandle nodeActiveHandle = null;
try
{
nodeActiveHandle = EventWaitHandle.OpenExisting(LocalNodeProviderGlobalNames.NodeActiveEventName(nodeNumber));
nodeIsActive = true;
}
catch (WaitHandleCannotBeOpenedException)
{
// Assume that the node is not running
}
finally
{
if (nodeActiveHandle != null)
{
nodeActiveHandle.Close();
}
}
return(nodeIsActive);
}
/// <summary>
/// This function launches a new node given a node index
/// </summary>
private void LaunchNode(int nodeIndex)
{
EventWaitHandle nodeReadyEvent = null;
string msbuildLocation = Path.Combine(locationOfMSBuildExe, "MSBuild.exe");
ErrorUtilities.VerifyThrow(File.Exists(msbuildLocation), "Msbuild.exe cannot be found at: " + msbuildLocation);
bool exitedDueToError = true;
try
{
NativeMethods.STARTUPINFO startInfo = new NativeMethods.STARTUPINFO();
startInfo.cb = Marshal.SizeOf(startInfo);
uint dwCreationFlags = NativeMethods.NORMAL_PRIORITY_CLASS;
if (!Engine.debugMode)
{
startInfo.hStdError = NativeMethods.InvalidHandle;
startInfo.hStdInput = NativeMethods.InvalidHandle;
startInfo.hStdOutput = NativeMethods.InvalidHandle;
startInfo.dwFlags = NativeMethods.STARTF_USESTDHANDLES;
dwCreationFlags = dwCreationFlags | NativeMethods.CREATE_NO_WINDOW;
}
NativeMethods.SECURITY_ATTRIBUTES pSec = new NativeMethods.SECURITY_ATTRIBUTES();
NativeMethods.SECURITY_ATTRIBUTES tSec = new NativeMethods.SECURITY_ATTRIBUTES();
pSec.nLength = Marshal.SizeOf(pSec);
tSec.nLength = Marshal.SizeOf(tSec);
NativeMethods.PROCESS_INFORMATION pInfo = new NativeMethods.PROCESS_INFORMATION();
string appName = msbuildLocation;
// Repeat the executable name as the first token of the command line because the command line
// parser logic expects it and will otherwise skip the first argument
string cmdLine = msbuildLocation + " /nologo /oldom /nodemode:" + nodeData[nodeIndex].NodeNumber;
NativeMethods.CreateProcess(appName, cmdLine,
ref pSec, ref tSec,
false, dwCreationFlags,
NativeMethods.NullPtr, null, ref startInfo, out pInfo);
nodeReadyEvent = new EventWaitHandle(false, EventResetMode.ManualReset, LocalNodeProviderGlobalNames.NodeActiveEventName(nodeData[nodeIndex].NodeNumber));
// Wait until the node is ready to process the requests
if (nodeReadyEvent.WaitOne(launchTimeout, false))
{
exitedDueToError = false;
}
}
finally
{
// Dispose before losing scope
if (nodeReadyEvent != null)
{
nodeReadyEvent.Close();
}
if (exitedDueToError)
{
nodeData[nodeIndex].CommunicationFailed = true;
}
}
}
/// <summary>
/// Create global events necessary for handshaking with the parent
/// </summary>
/// <param name="nodeNumber"></param>
/// <returns>True if events created successfully and false otherwise</returns>
private static bool CreateGlobalEvents(int nodeNumber)
{
bool createdNew = false;
if (NativeMethods.IsUserAdministrator())
{
EventWaitHandleSecurity mSec = new EventWaitHandleSecurity();
// Add a rule that grants the access only to admins and systems
mSec.SetSecurityDescriptorSddlForm(NativeMethods.ADMINONLYSDDL);
// Create an initiation event to allow the parent side to prove to the child that we have the same level of privilege as it does.
// this is done by having the parent set this event which means it needs to have administrative permissions to do so.
globalInitiateActivationEvent = new EventWaitHandle(false, EventResetMode.ManualReset, LocalNodeProviderGlobalNames.NodeInitiateActivationEventName(nodeNumber), out createdNew, mSec);
}
else
{
// Create an initiation event to allow the parent side to prove to the child that we have the same level of privilege as it does.
// this is done by having the parent set this event which means it has atleast the same permissions as the child process
globalInitiateActivationEvent = new EventWaitHandle(false, EventResetMode.ManualReset, LocalNodeProviderGlobalNames.NodeInitiateActivationEventName(nodeNumber), out createdNew);
}
// This process must be the creator of the event to prevent squating by a lower privilaged attacker
if (!createdNew)
{
return(false);
}
// Informs the parent process that the child process has been created.
globalNodeActive = new EventWaitHandle(false, EventResetMode.ManualReset, LocalNodeProviderGlobalNames.NodeActiveEventName(nodeNumber));
globalNodeActive.Set();
// Indicate to the parent process, this node is currently is ready to start to recieve requests
globalNodeInUse = new EventWaitHandle(false, EventResetMode.ManualReset, LocalNodeProviderGlobalNames.NodeInUseEventName(nodeNumber));
// Used by the parent process to inform the child process to shutdown due to the child process
// not recieving the initialization command.
globalNodeErrorShutdown = new EventWaitHandle(false, EventResetMode.ManualReset, LocalNodeProviderGlobalNames.NodeErrorShutdownEventName(nodeNumber));
// Inform the parent process the node has started its communication threads.
globalNodeActivate = new EventWaitHandle(false, EventResetMode.ManualReset, LocalNodeProviderGlobalNames.NodeActivedEventName(nodeNumber));
return(true);
}