Method ConvertDosNameToNtName

KernelLibrary/FileManager.cpp:94–152

}

NTSTATUS FileManager::ConvertDosNameToNtName(_In_ PCWSTR dosName, _Out_ PUNICODE_STRING ntName) {
	ntName->Buffer = nullptr;	// in case of failure
	auto dosNameLen = ::wcslen(dosName);

	if (dosNameLen < 3)
		return STATUS_BUFFER_TOO_SMALL;

	// make sure we have a driver letter
	if (dosName[2] != L'\\' || dosName[1] != L':')
		return STATUS_INVALID_PARAMETER;

	kstring<'rgmf'> symLink(L"\\??\\");
	symLink.Append(dosName, 2);		// driver letter and colon

	UNICODE_STRING symLinkFull;
	symLink.GetUnicodeString(&symLinkFull);

	OBJECT_ATTRIBUTES symLinkAttr;
	InitializeObjectAttributes(&symLinkAttr, &symLinkFull,
		OBJ_KERNEL_HANDLE | OBJ_CASE_INSENSITIVE, nullptr, nullptr);

	HANDLE hSymLink = nullptr;
	auto status = STATUS_SUCCESS;

	do
	{
		// open symbolic link
		status = ZwOpenSymbolicLinkObject(&hSymLink, GENERIC_READ, &symLinkAttr);
		if (!NT_SUCCESS(status))
			break;
		USHORT maxLen = 1024;	// arbitray
		ntName->Buffer = (WCHAR*)ExAllocatePool(PagedPool, maxLen);
		if (!ntName->Buffer) {
			status = STATUS_INSUFFICIENT_RESOURCES;
			break;
		}
		ntName->MaximumLength = maxLen;

		// read target of symbolic link
		status = ZwQuerySymbolicLinkObject(hSymLink, ntName, nullptr);
		if (!NT_SUCCESS(status))
			break;
	} while (false);

	if (!NT_SUCCESS(status)) {
		if (ntName->Buffer) {
			ExFreePool(ntName->Buffer);
			ntName->Buffer = nullptr;
		}
	}
	else {
		RtlAppendUnicodeToString(ntName, dosName + 2);	// directory part
	}

	if (hSymLink)
		ZwClose(hSymLink);

	return status;