encryptedioqueue.c

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			}

			// Divide data block to fragments to enable efficient overlapping of encryption and IO operations

			dataRemaining = item->OriginalLength;
			fragmentOffset = item->OriginalOffset;

			while (dataRemaining > 0)
			{
				BOOL isLastFragment = dataRemaining <= TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE;
				
				ULONG dataFragmentLength = isLastFragment ? dataRemaining : TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE;
				activeFragmentBuffer = (activeFragmentBuffer == queue->FragmentBufferA ? queue->FragmentBufferB : queue->FragmentBufferA);

				// Create IO request
				request = (EncryptedIoRequest *) TCalloc (sizeof (EncryptedIoRequest));
				if (!request)
				{
					while (InterlockedExchangeAdd (&item->OutstandingRequestCount, 0) > 0)
						KeWaitForSingleObject (&queue->RequestCompletedEvent, Executive, KernelMode, FALSE, NULL);

					CompleteOriginalIrp (item, STATUS_INSUFFICIENT_RESOURCES, 0);
					break;
				}

				request->Item = item;
				request->CompleteOriginalIrp = isLastFragment;
				request->Offset = fragmentOffset;
				request->Data = activeFragmentBuffer;
				request->OrigDataBufferFragment = dataBuffer;
				request->Length = dataFragmentLength;

				if (queue->IsFilterDevice)
				{
					// Get intersection of data fragment with encrypted area
					GetIntersection (fragmentOffset.QuadPart, dataFragmentLength, queue->EncryptedAreaStart, queue->EncryptedAreaEnd, &intersectStart, &intersectLength);

					request->EncryptedOffset = intersectStart - fragmentOffset.QuadPart;
					request->EncryptedLength = intersectLength;
				}
				else
				{
					request->EncryptedOffset = 0;
					request->EncryptedLength = dataFragmentLength;
				}

				AcquireFragmentBuffer (queue, activeFragmentBuffer);

				if (item->Write)
				{
					// Encrypt data
					memcpy (activeFragmentBuffer, dataBuffer, dataFragmentLength);

					if (request->EncryptedLength > 0)
					{
						UINT64_STRUCT dataUnit;
						ASSERT (request->EncryptedOffset + request->EncryptedLength <= request->Offset.QuadPart + request->Length);

						dataUnit.Value = (request->Offset.QuadPart + request->EncryptedOffset) / ENCRYPTION_DATA_UNIT_SIZE;

						if (queue->CryptoInfo->bPartitionInInactiveSysEncScope)
							dataUnit.Value += queue->CryptoInfo->FirstDataUnitNo.Value;

						EncryptDataUnits (activeFragmentBuffer + request->EncryptedOffset, &dataUnit, request->EncryptedLength / ENCRYPTION_DATA_UNIT_SIZE, queue->CryptoInfo);
					}
				}

				// Queue IO request
				InterlockedIncrement (&item->OutstandingRequestCount);

				ExInterlockedInsertTailList (&queue->IoThreadQueue, &request->ListEntry, &queue->IoThreadQueueLock);
				KeSetEvent (&queue->IoThreadQueueNotEmptyEvent, IO_DISK_INCREMENT, FALSE);

				if (isLastFragment)
					break;

				dataRemaining -= TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE;
				dataBuffer += TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE;
				fragmentOffset.QuadPart += TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE;
			}
		}
	}

	PsTerminateSystemThread (STATUS_SUCCESS);
}


NTSTATUS EncryptedIoQueueAddIrp (EncryptedIoQueue *queue, PIRP irp)
{
	EncryptedIoQueueItem *item;
	PIO_STACK_LOCATION origIrpSp = IoGetCurrentIrpStackLocation (irp);
	NTSTATUS status;

	InterlockedIncrement (&queue->OutstandingIoCount);
	if (queue->StopPending)
	{
		Dump ("STATUS_DEVICE_NOT_READY  out=%d\n", queue->OutstandingIoCount);
		status = STATUS_DEVICE_NOT_READY;
		goto err;
	}

	if (queue->IsFilterDevice)
	{
		status = IoAcquireRemoveLock (&queue->RemoveLock, irp);
		if (!NT_SUCCESS (status))
			goto err;
	}

	item = TCalloc (sizeof (EncryptedIoQueueItem));
	if (!item)
	{
		status = STATUS_INSUFFICIENT_RESOURCES;
		goto err;
	}

	memset (item, 0, sizeof (EncryptedIoQueueItem));

	switch (origIrpSp->MajorFunction)
	{
	case IRP_MJ_READ:
		item->Write = FALSE;
		item->OriginalOffset = origIrpSp->Parameters.Read.ByteOffset;
		item->OriginalLength = origIrpSp->Parameters.Read.Length;
		break;

	case IRP_MJ_WRITE:
		item->Write = TRUE;
		item->OriginalOffset = origIrpSp->Parameters.Write.ByteOffset;
		item->OriginalLength = origIrpSp->Parameters.Write.Length;
		break;

	default:
		TCfree (item);
		status = STATUS_INVALID_PARAMETER;
		goto err;
	}

	item->Queue = queue;
	item->OriginalIrp = irp;
	item->OutstandingRequestCount = 0;
	item->Status = STATUS_SUCCESS;

	IoMarkIrpPending (irp);

	//Dump ("Queue add %I64d %I64d  out=%d\n", item->OriginalOffset, item->OriginalLength, queue->OutstandingIoCount);

	ExInterlockedInsertTailList (&queue->MainThreadQueue, &item->ListEntry, &queue->MainThreadQueueLock);
	KeSetEvent (&queue->MainThreadQueueNotEmptyEvent, IO_DISK_INCREMENT, FALSE);
	
	return STATUS_PENDING;

err:
	DecrementOutstandingIoCount (queue);
	return status;
}


NTSTATUS EncryptedIoQueueHoldWhenIdle (EncryptedIoQueue *queue, int64 timeout)
{
	NTSTATUS status;
	ASSERT (!queue->Suspended);

	queue->SuspendPending = TRUE;
	
	while (TRUE)
	{
		while (InterlockedExchangeAdd (&queue->OutstandingIoCount, 0) > 0)
		{
			LARGE_INTEGER waitTimeout;

			waitTimeout.QuadPart = timeout * -10000;
			status = KeWaitForSingleObject (&queue->NoOutstandingIoEvent, Executive, KernelMode, FALSE, timeout != 0 ? &waitTimeout : NULL);

			if (status == STATUS_TIMEOUT)
				status = STATUS_UNSUCCESSFUL;

			if (!NT_SUCCESS (status))
				return status;
		}

		KeClearEvent (&queue->QueueResumedEvent);
		queue->Suspended = TRUE;

		if (InterlockedExchangeAdd (&queue->OutstandingIoCount, 0) == 0)
			break;

		queue->Suspended = FALSE;
		KeSetEvent (&queue->QueueResumedEvent, IO_DISK_INCREMENT, FALSE);

	}

	queue->SuspendPending = FALSE;
	//Dump ("Queue suspended  out=%d\n", queue->OutstandingIoCount);

	return STATUS_SUCCESS;
}


BOOL EncryptedIoQueueIsSuspended (EncryptedIoQueue *queue)
{
	return queue->Suspended;
}


BOOL EncryptedIoQueueIsRunning (EncryptedIoQueue *queue)
{
	return !queue->StopPending;
}


NTSTATUS EncryptedIoQueueResumeFromHold (EncryptedIoQueue *queue)
{
	ASSERT (queue->Suspended);
	
	queue->Suspended = FALSE;
	KeSetEvent (&queue->QueueResumedEvent, IO_DISK_INCREMENT, FALSE);

	//Dump ("Queue resumed  out=%d\n", queue->OutstandingIoCount);

	return STATUS_SUCCESS;
}


NTSTATUS EncryptedIoQueueStart (EncryptedIoQueue *queue, PEPROCESS process)
{
	NTSTATUS status;
	queue->ThreadExitRequested = FALSE;

	KeInitializeEvent (&queue->NoOutstandingIoEvent, SynchronizationEvent, FALSE);
	KeInitializeEvent (&queue->RequestCompletedEvent, SynchronizationEvent, FALSE);
	KeInitializeEvent (&queue->QueueResumedEvent, SynchronizationEvent, FALSE);

	queue->FragmentBufferA = TCalloc (TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE);
	if (!queue->FragmentBufferA)
		goto noMemory;

	queue->FragmentBufferB = TCalloc (TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE);
	if (!queue->FragmentBufferB)
		goto noMemory;

	KeInitializeEvent (&queue->FragmentBufferAFreeEvent, SynchronizationEvent, TRUE);
	KeInitializeEvent (&queue->FragmentBufferBFreeEvent, SynchronizationEvent, TRUE);

	// Main thread
	InitializeListHead (&queue->MainThreadQueue);
	KeInitializeSpinLock (&queue->MainThreadQueueLock);
	KeInitializeEvent (&queue->MainThreadQueueNotEmptyEvent, SynchronizationEvent, FALSE);

	status = TCStartThread (MainThreadProc, queue, &queue->MainThread);
	if (!NT_SUCCESS (status))
		goto err;

	// IO thread
	InitializeListHead (&queue->IoThreadQueue);
	KeInitializeSpinLock (&queue->IoThreadQueueLock);
	KeInitializeEvent (&queue->IoThreadQueueNotEmptyEvent, SynchronizationEvent, FALSE);

	status = TCStartThreadInProcess (IoThreadProc, queue, &queue->IoThread, process);
	if (!NT_SUCCESS (status))
	{
		queue->ThreadExitRequested = TRUE;
		TCStopThread (queue->MainThread, &queue->MainThreadQueueNotEmptyEvent);
		goto err;
	}

	// Completion thread
	InitializeListHead (&queue->CompletionThreadQueue);
	KeInitializeSpinLock (&queue->CompletionThreadQueueLock);
	KeInitializeEvent (&queue->CompletionThreadQueueNotEmptyEvent, SynchronizationEvent, FALSE);

	status = TCStartThread (CompletionThreadProc, queue, &queue->CompletionThread);
	if (!NT_SUCCESS (status))
	{
		queue->ThreadExitRequested = TRUE;
		TCStopThread (queue->MainThread, &queue->MainThreadQueueNotEmptyEvent);
		TCStopThread (queue->IoThread, &queue->IoThreadQueueNotEmptyEvent);
		goto err;
	}

	queue->StopPending = FALSE;
	Dump ("Queue started\n");
	return STATUS_SUCCESS;

noMemory:
	status = STATUS_INSUFFICIENT_RESOURCES;

err:
	if (queue->FragmentBufferA)
		TCfree (queue->FragmentBufferA);
	if (queue->FragmentBufferB)
		TCfree (queue->FragmentBufferB);

	return status;
}


NTSTATUS EncryptedIoQueueStop (EncryptedIoQueue *queue)
{
	ASSERT (!queue->StopPending);
	queue->StopPending = TRUE;
	
	while (InterlockedExchangeAdd (&queue->OutstandingIoCount, 0) > 0)
	{
		KeWaitForSingleObject (&queue->NoOutstandingIoEvent, Executive, KernelMode, FALSE, NULL);
	}

	Dump ("Queue stopping  out=%d\n", queue->OutstandingIoCount);

	queue->ThreadExitRequested = TRUE;

	TCStopThread (queue->MainThread, &queue->MainThreadQueueNotEmptyEvent);
	TCStopThread (queue->IoThread, &queue->IoThreadQueueNotEmptyEvent);
	TCStopThread (queue->CompletionThread, &queue->CompletionThreadQueueNotEmptyEvent);

	TCfree (queue->FragmentBufferA);
	TCfree (queue->FragmentBufferB);

	Dump ("Queue stopped  out=%d\n", queue->OutstandingIoCount);
	return STATUS_SUCCESS;
}