NTQueryObject - STATUS_INVALID_INFO_CLASS error

Question

when using the Delphi code provided as answer on this page,

Delphi - get what files are opened by an application

I get nice results on Windows 8 but an error on XP in the provided function "GetObjectInfo" : NTQueryObject called at line 4 is returning STATUS_INVALID_INFO_CLASS (3221225475).

It seems that the class ObjectNameInformation is not a valid info class.

I use Delphi 7.

program ListAllHandles;

{$APPTYPE CONSOLE}

uses
  PSApi,
  Windows,
  SysUtils;

const
SystemHandleInformation       = $10;
STATUS_SUCCESS               = $00000000;
STATUS_BUFFER_OVERFLOW        = $80000005;
STATUS_INFO_LENGTH_MISMATCH   = $C0000004;
DefaulBUFFERSIZE              = $100000;


type
 OBJECT_INFORMATION_CLASS = (ObjectBasicInformation,ObjectNameInformation,ObjectTypeInformation,ObjectAllTypesInformation,ObjectHandleInformation );

 SYSTEM_HANDLE=packed record
 uIdProcess:ULONG;
 ObjectType:UCHAR;
 Flags     :UCHAR;
 Handle    :Word;
 pObject   :Pointer;
 GrantedAccess:ACCESS_MASK;
 end;

 PSYSTEM_HANDLE      = ^SYSTEM_HANDLE;
 SYSTEM_HANDLE_ARRAY = Array[0..0] of SYSTEM_HANDLE;
 PSYSTEM_HANDLE_ARRAY= ^SYSTEM_HANDLE_ARRAY;

  SYSTEM_HANDLE_INFORMATION=packed record
 uCount:ULONG;
 Handles:SYSTEM_HANDLE_ARRAY;
 end;
 PSYSTEM_HANDLE_INFORMATION=^SYSTEM_HANDLE_INFORMATION;

 TNtQuerySystemInformation=function (SystemInformationClass:DWORD; SystemInformation:pointer; SystemInformationLength:DWORD;  ReturnLength:PDWORD):THandle; stdcall;
 TNtQueryObject           =function (ObjectHandle:cardinal; ObjectInformationClass:OBJECT_INFORMATION_CLASS; ObjectInformation:pointer; Length:ULONG;ResultLength:PDWORD):THandle;stdcall;

 UNICODE_STRING=packed record
    Length       :Word;
    MaximumLength:Word;
    Buffer       :PWideChar;
 end;

 OBJECT_NAME_INFORMATION=UNICODE_STRING;
 POBJECT_NAME_INFORMATION=^OBJECT_NAME_INFORMATION;

Var
 NTQueryObject           :TNtQueryObject;
 NTQuerySystemInformation:TNTQuerySystemInformation;


function GetObjectInfo(hObject:cardinal; objInfoClass:OBJECT_INFORMATION_CLASS):LPWSTR;
var
 pObjectInfo:POBJECT_NAME_INFORMATION;
 HDummy     :THandle;
 dwSize     :DWORD;
begin
  Result:=nil;
  dwSize      := sizeof(OBJECT_NAME_INFORMATION);
  pObjectInfo := AllocMem(dwSize);
  HDummy      := NTQueryObject(hObject, objInfoClass, pObjectInfo,dwSize, @dwSize);

  if((HDummy = STATUS_BUFFER_OVERFLOW) or (HDummy = STATUS_INFO_LENGTH_MISMATCH)) then
    begin
   FreeMem(pObjectInfo);
   pObjectInfo := AllocMem(dwSize);
   HDummy      := NTQueryObject(hObject, objInfoClass, pObjectInfo,dwSize, @dwSize);
  end;

  if((HDummy >= STATUS_SUCCESS) and (pObjectInfo.Buffer <> nil)) then
  begin
   Result := AllocMem(pObjectInfo.Length + sizeof(WCHAR));
   CopyMemory(result, pObjectInfo.Buffer, pObjectInfo.Length);
  end;
  FreeMem(pObjectInfo);
end;

Procedure EnumerateOpenFiles();
var
 sDummy      : string;
 hProcess    : THandle;
 hObject     : THandle;
 ResultLength: DWORD;
 aBufferSize : DWORD;
 aIndex      : Integer;
 pHandleInfo : PSYSTEM_HANDLE_INFORMATION;
 HDummy      : THandle;
 lpwsName    : PWideChar;
 lpwsType    : PWideChar;
 lpszProcess : PAnsiChar;
begin
    AbufferSize      := DefaulBUFFERSIZE;
  pHandleInfo      := AllocMem(AbufferSize);
  HDummy           := NTQuerySystemInformation(DWORD(SystemHandleInformation), pHandleInfo,AbufferSize, @ResultLength);  //Get the list of handles

  if(HDummy = STATUS_SUCCESS) then  //If no error continue
    begin

      for aIndex:=0 to pHandleInfo^.uCount-1 do   //iterate the list
      begin
    hProcess := OpenProcess(PROCESS_DUP_HANDLE or PROCESS_QUERY_INFORMATION or PROCESS_VM_READ, FALSE, pHandleInfo.Handles[aIndex].uIdProcess);  //open the process to get aditional info
    if(hProcess <> INVALID_HANDLE_VALUE) then  //Check valid handle
        begin
     hObject := 0;
     if DuplicateHandle(hProcess, pHandleInfo.Handles[aIndex].Handle,GetCurrentProcess(), @hObject, STANDARD_RIGHTS_REQUIRED,FALSE, 0) then  //Get  a copy of the original handle
          begin
      lpwsName := GetObjectInfo(hObject, ObjectNameInformation); //Get the filename linked to the handle
      if (lpwsName <> nil)  then
            begin
       lpwsType    := GetObjectInfo(hObject, ObjectTypeInformation);
       lpszProcess := AllocMem(MAX_PATH);

       if GetModuleFileNameEx(hProcess, 0,lpszProcess, MAX_PATH)<>0 then  //get the name of the process
               sDummy:=ExtractFileName(lpszProcess)
              else
               sDummy:= 'System Process';

              Writeln('PID      ',pHandleInfo.Handles[aIndex].uIdProcess);
              Writeln('Handle   ',pHandleInfo.Handles[aIndex].Handle);
              Writeln('Process  ',sDummy);
              Writeln('FileName ',string(lpwsName));
              Writeln;

              FreeMem(lpwsName);
              FreeMem(lpwsType);
              FreeMem(lpszProcess);
      end;
      CloseHandle(hObject);
     end;
     CloseHandle(hProcess);
    end;
   end;
  end;
  FreeMem(pHandleInfo);

Any help ?

[MSDN suggests](http://msdn.microsoft.com/en-us/library/bb432383(v=vs.85).aspx) that `NtQueryObject` only accepts `ObjectBasicInformation` or `ObjectTypeInformation`. It also says *"This function may be changed or removed from Windows without further notice"*, which is worrying. — Roger Rowland, Aug 24 '13 at 08:15
Review the code if you want to make use of it. F.i. OpenProcess does not return INVALID_HANDLE_VALUE when it fails. — Sertac Akyuz, Aug 24 '13 at 14:30

score 4 · Accepted Answer · answered Aug 24 '13 at 08:39

There are a number of errors in your translation:

In C an enum has a minimum size of 4 bytes, so you should set {$ENUMSIZE 4}
Records should not be packed but aligned
NtQueryObject doesn't return a handle but an NTSTATUS

My advise is to use the existing translations in the Jedi Apilib since they are time tested. You need the JwaNative unit.

On my blog you can find a complete example on enumerating all handles: http://www.remkoweijnen.nl/blog/2012/03/07/running-multiple-instances-of-lync-howto/

NTQueryObject - STATUS_INVALID_INFO_CLASS error

1 Answers1