unit NTApi;

interface
uses windows,sysutils;

type
 NT_STATUS = Cardinal;

function NtQuerySystemInformation(SystemInformationClass: DWORD; SystemInformation: Pointer;
SystemInformationLength:DWORD; ReturnLength:PDWORD):NT_STATUS; stdcall;

type
 PIO_STATUS_BLOCK = ^IO_STATUS_BLOCK;
 IO_STATUS_BLOCK = packed record
   Status: NT_STATUS;
   Information: DWORD;
 end;
 TIOStatusBlock=IO_STATUS_BLOCK;

 PFILE_NAME_INFORMATION = ^FILE_NAME_INFORMATION;
 FILE_NAME_INFORMATION = packed record
   FileNameLength: ULONG;
   FileName: array [0..MAX_PATH - 1] of WideChar;
 end;
 TFileNameInformation=FILE_NAME_INFORMATION;

 PUNICODE_STRING = ^TUNICODE_STRING;
 TUNICODE_STRING = packed record
   Length : WORD;
   MaximumLength : WORD;
   Buffer : array [0..MAX_PATH - 1] of WideChar;
 end;

 POBJECT_NAME_INFORMATION = ^OBJECT_NAME_INFORMATION;
 OBJECT_NAME_INFORMATION = packed record
   Name : TUNICODE_STRING;
 end;
 TObjectNameInformation=OBJECT_NAME_INFORMATION;

const
 STATUS_SUCCESS = NT_STATUS($00000000);
 STATUS_INVALID_INFO_CLASS = NT_STATUS($C0000003);
 STATUS_INFO_LENGTH_MISMATCH = NT_STATUS($C0000004);
 STATUS_INVALID_DEVICE_REQUEST = NT_STATUS($C0000010);
 ObjectNameInformation = 1;
 FileDirectoryInformation = 1;
 FileNameInformation = 9;
 SystemProcessesAndThreadsInformation = 5;
 SystemHandleInformation = 16;

function NtQueryInformationFile(FileHandle: THandle; IoStatusBlock: PIO_STATUS_BLOCK; FileInformation: Pointer;
Length: DWORD; FileInformationClass: DWORD): NT_STATUS; stdcall;

function NtQueryObject(ObjectHandle: THandle; ObjectInformationClass: DWORD; ObjectInformation: Pointer;
   ObjectInformationLength: ULONG; ReturnLength: PDWORD): NT_STATUS; stdcall;

function GetLongPathNameA(lpszShortPath, lpszLongPath: PChar;
   cchBuffer: DWORD): DWORD; stdcall; external kernel32 name 'GetLongPathNameA';

const
 ntdll  = 'ntdll.dll';

function GetFileNameByHandle(FileHandle: THandle):string;

implementation

function NtQuerySystemInformation; external ntdll name 'NtQuerySystemInformation';
function NtQueryInformationFile; external ntdll name 'NtQueryInformationFile';
function NtQueryObject; external ntdll name 'NtQueryObject';

function GetFileNameByHandle(FileHandle: THandle):string;
var
 FileNameInfo: TFileNameInformation;
 ObjectNameInfo: TObjectNameInformation;
 IoStatusBlock: TIOStatusBlock;
 res,dwReturn: DWORD;
begin
 result:='';
 res := NtQueryInformationFile(FileHandle,@IoStatusBlock,@FileNameInfo,
   SizeOf(FileNameInfo.FileName),FileNameInformation);
 if res = STATUS_SUCCESS then
 begin
   res := NtQueryObject(FileHandle,ObjectNameInformation,
     @ObjectNameInfo, SizeOf(ObjectNameInfo.Name.Buffer), @dwReturn);
   if res = STATUS_SUCCESS then
   begin
     SetLength(result,MAX_PATH);
     SetLength(result,WideCharToMultiByte(CP_ACP, 0,
       @ObjectNameInfo.Name.Buffer[ObjectNameInfo.Name.MaximumLength -
       ObjectNameInfo.Name.Length],
       ObjectNameInfo.Name.Length div SizeOf(WideChar),
       @result[1],MAX_PATH, nil, nil));
   end else
   begin
     SetLength(result,MAX_PATH);
     SetLength(result,WideCharToMultiByte(CP_ACP, 0,
       @FileNameInfo.FileName[0], FileNameInfo.FileNameLength div SizeOf(WideChar),
       @result[1],MAX_PATH, nil, nil));
   end;
 end;
end;

end.

// device file name -> DOS file name
function GetDOSFileName(lpDeviceFileName:pchar):string;
var
lpDeviceName:array[0..$1000-1] of char;
lpDrive:array[0..2] of char;
actDrive:char;
begin
 Result:=lpDeviceFileName;
lpDrive := 'A:';
for actDrive :='A' to 'Z' do
begin
 lpDrive[0] := actDrive;
 if (QueryDosDevice(lpDrive, lpDeviceName, $1000) <> 0) then
 begin
     if (CompareString(LOCALE_SYSTEM_DEFAULT,NORM_IGNORECASE,lpDeviceName,lstrlen(lpDevi ceName),
                      lpDeviceFileName,lstrlen(lpDeviceName))=CSTR_EQUAL) then
  begin
   Result:=string(lpDrive)+PChar(cardinal(lpDeviceFileName) + lstrlen(lpDeviceName));
   break
  end
 end
end
end;

// DOS file name -> device file name
function GetDeviceFileName(lpDOSFileName:pchar):string;
var
lpDrive:array[0..2] of char;
lpDeviceName:array[0..$1000-1] of char;
begin
 Result:=lpDOSFileName;
lstrcpyn(lpDrive,lpDOSFileName,3);
if (QueryDosDevice(lpDrive, lpDeviceName, $1000 )<>0) then
begin
   if (CompareString(LOCALE_SYSTEM_DEFAULT,NORM_IGNORECASE,'\??\',4,
                      lpDeviceName,4)=CSTR_EQUAL) then
 begin
  Result:=PChar(lpDeviceName + 4)+ string(PChar(lpDOSFileName + 2));
  exit
 end;
 lstrcat(lpDeviceName, lpDOSFileName + 2 );
 Result := lpDeviceName
end
end;