// Note: in order to be consistent with other messagings (e.g. TcpMessaging) value 0 for timeouts mean infinite time.
public SharedMemoryReceiver(string memoryMappedFileName, bool useExistingMemoryMappedFile, TimeSpan openTimeout, int maxMessageSize, MemoryMappedFileSecurity memmoryMappedFileSecurity)
{
using (EneterTrace.Entering())
{
myOpenTimeout = (openTimeout == TimeSpan.Zero) ? TimeSpan.FromMilliseconds(-1) : openTimeout;
myMemoryMappedFileName = memoryMappedFileName;
myMaxMessageSize = maxMessageSize;
// If true then the listener will not create the new memory shared file but will open existing one.
// This is useful for security restrictions if the functionality is used in the windows service.
myUseExistingMemoryMappedFile = useExistingMemoryMappedFile;
myMemmoryMappedFileSecurity = memmoryMappedFileSecurity;
// If the security shall be applied.
if (myMemmoryMappedFileSecurity != null)
{
// Create the security for the WaitHandle sync logic.
myEventWaitHandleSecurity = new EventWaitHandleSecurity();
myEventWaitHandleSecurity.SetSecurityDescriptorSddlForm("S:(ML;;NW;;;LW)");
SecurityIdentifier aSid = new SecurityIdentifier(WellKnownSidType.WorldSid, null);
EventWaitHandleAccessRule anAccessRule = new EventWaitHandleAccessRule(aSid,
EventWaitHandleRights.Modify | EventWaitHandleRights.Synchronize,
AccessControlType.Allow);
myEventWaitHandleSecurity.AddAccessRule(anAccessRule);
}
}
}
/// <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;
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);
}
// Note: in order to be consistent with other messagings (e.g. TcpMessaging) value 0 for timeouts mean infinite time.
public SharedMemorySender(string memoryMappedFileName, bool useExistingMemoryMappedFile, TimeSpan openTimeout, TimeSpan sendTimeout, int maxMessageSize, MemoryMappedFileSecurity memoryMappedFileSecurity)
{
using (EneterTrace.Entering())
{
try
{
mySendTimeout = (sendTimeout == TimeSpan.Zero) ? TimeSpan.FromMilliseconds(-1) : sendTimeout;
myUseExistingMemoryMappedFile = useExistingMemoryMappedFile;
myMaxMessageSize = maxMessageSize;
// If the shared memory file is created by SharedMemoryReceiver then open existing one.
if (useExistingMemoryMappedFile)
{
TimeSpan anOpenTimeout = (openTimeout == TimeSpan.Zero) ? TimeSpan.FromMilliseconds(-1) : openTimeout;
// Try to open synchronization handlers.
mySharedMemoryReady = EventWaitHandleExt.OpenExisting(memoryMappedFileName + "_SharedMemoryReady", anOpenTimeout);
mySharedMemoryFilled = EventWaitHandleExt.OpenExisting(memoryMappedFileName + "_SharedMemoryFilled", anOpenTimeout);
mySharedMemoryCreated = EventWaitHandleExt.OpenExisting(memoryMappedFileName + "_ResponseSharedMemoryCreated", anOpenTimeout);
// Wait until the memory mapped file exist and then open it.
// Note: it shall be created by SharedMemoryReceiver.
if (!mySharedMemoryCreated.WaitOne(anOpenTimeout))
{
throw new InvalidOperationException(TracedObject + "failed to open memory mapped file because it does not exist.");
}
myMemoryMappedFile = MemoryMappedFile.OpenExisting(memoryMappedFileName);
}
// If the shared memory file shall be created by SharedMemorySender.
else
{
EventWaitHandleSecurity anEventWaitHandleSecurity = null;
if (memoryMappedFileSecurity != null)
{
// Create the security for the WaitHandle logic.
anEventWaitHandleSecurity = new EventWaitHandleSecurity();
anEventWaitHandleSecurity.SetSecurityDescriptorSddlForm("S:(ML;;NW;;;LW)");
SecurityIdentifier aSid = new SecurityIdentifier(WellKnownSidType.WorldSid, null);
EventWaitHandleAccessRule anAccessRule = new EventWaitHandleAccessRule(aSid,
EventWaitHandleRights.Modify | EventWaitHandleRights.Synchronize,
AccessControlType.Allow);
anEventWaitHandleSecurity.AddAccessRule(anAccessRule);
}
// Create synchronization handlers.
bool aDummy;
mySharedMemoryReady = new EventWaitHandle(false, EventResetMode.AutoReset, memoryMappedFileName + "_SharedMemoryReady", out aDummy, anEventWaitHandleSecurity);
mySharedMemoryFilled = new EventWaitHandle(false, EventResetMode.AutoReset, memoryMappedFileName + "_SharedMemoryFilled", out aDummy, anEventWaitHandleSecurity);
mySharedMemoryCreated = new EventWaitHandle(false, EventResetMode.ManualReset, memoryMappedFileName + "_ResponseSharedMemoryCreated", out aDummy, anEventWaitHandleSecurity);
// Create the memory mapped file.
myMemoryMappedFile = MemoryMappedFile.CreateNew(memoryMappedFileName, maxMessageSize, MemoryMappedFileAccess.ReadWrite, MemoryMappedFileOptions.None, memoryMappedFileSecurity, HandleInheritability.None);
// Indicate the shared memory is created.
mySharedMemoryCreated.Set();
}
myMemoryMappedFileStream = myMemoryMappedFile.CreateViewStream();
}
catch (Exception err)
{
EneterTrace.Error(TracedObject + "failed to create SharedMemorySender.", err);
// Dispose resources alocated so far.
Dispose();
throw;
}
}
}
