Gruppennamen ermitteln

[IB-Software]

Hallo,

ich möchte unter NT Systemen die Namen der Standardbenutzergruppen ermitteln.
Dazu verwende ich folgende Funktion:

Delphi-Quellcode:

function GetGroupName(index:integer):string;
const DOMAIN_ALIAS_RID_ADMINS = $00000220;
      DOMAIN_ALIAS_RID_GUESTS = $00000222;
      DOMAIN_ALIAS_RID_USERS =  $00000221;
      SECURITY_WORLD_RID = $00000000;
      SECURITY_BUILTIN_DOMAIN_RID = $00000020;
var    Error, rid:integer;
      NameSize, DomainNameSize:DWORD;
      sia:SID_IDENTIFIER_AUTHORITY;
      TargetComputer,DomainName, Name:pchar;
      sid:psid;
      sidType: SID_NAME_USE;
      APISuccess : boolean;

begin
  Case index of
        0 : Rid := DOMAIN_ALIAS_RID_ADMINS;
        1 : Rid := DOMAIN_ALIAS_RID_GUESTS;
        2 : Rid := DOMAIN_ALIAS_RID_USERS;
        3 : Rid := 0;
  end;
  TargetComputer := '';
  NameSize := 1024;
  DomainNameSize := 1024;
  GetMem(Name, 1024);
  GetMem(DomainName, 1024);

  If Rid = 0 then
        begin
         sia.Value[5] := 1;
         If AllocateAndInitializeSid(sia, 1, SECURITY_WORLD_RID, Rid, 0, 0, 0, 0, 0, 0, Sid) then
         begin

            APISuccess := LookupAccountSid(nil, Sid,Name, NameSize, DomainName, DomainNameSize, sidType);
            if APISuccess then begin
                if Assigned(sid) then FreeSid(sid)
             end else begin
                 exit
             end;
          End;
      end else begin
         sia.Value[5] := 5 ;
         If AllocateAndInitializeSid(sia, 2, SECURITY_BUILTIN_DOMAIN_RID, Rid, 0, 0, 0, 0, 0, 0, Sid) then
         begin
             APISuccess := LookupAccountSid(nil, Sid, Name, NameSize, DomainName, DomainNameSize, sidType);
             if APISuccess then begin
                if Assigned(sid) then FreeSid(sid)
             end else begin
                 exit
             end;
          End;
        End;
  result := Name;

end;

Die FunktionLookupAccountSid(nil, Sid, Name, NameSize, DomainName, DomainNameSize, sidType); gibt allerdings immer ein 'false' wieder.

Wo ist mein Denkfehler.

Danke schonmal im voraus.

Ingo