unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Classes, Vcl.Graphics, Vcl.Controls, Vcl.SvcMgr, Vcl.Dialogs;

type
  TService1 = class(TService)
    procedure ServiceCreate(Sender: TObject);
  private
    { Private declarations }
    FWrapper: TServiceController;
  public
    function GetServiceController: TServiceController; override;
    { Public declarations }
  end;

var
  Service1: TService1;

implementation

{$R *.dfm}

var
  ExecutableHeap: THandle;

procedure CreateExecutableHeap;
begin
  ExecutableHeap := HeapCreate($00040000{HEAP_CREATE_ENABLE_EXECUTE}, 0, 0);
end;

procedure DestroyExecutableHeap;
begin
  HeapDestroy(ExecutableHeap);
  ExecutableHeap := 0;
end;

function AllocExecutableMemory(const Size: Integer): Pointer;
begin
  Result := nil;
  if (ExecutableHeap <> 0) then
    Result := HeapAlloc(ExecutableHeap, 0, Size);
end;

// -------------------------------------------------------------

procedure ServiceController(CtrlCode: DWord); stdcall;
begin
  Service1.Controller(CtrlCode);
end;

function TService1.GetServiceController: TServiceController;
begin
  Result := FWrapper; //ServiceController;
end;

procedure TService1.ServiceCreate(Sender: TObject);
var
  Code: PByte;
begin
  Code := AllocExecutableMemory(5);
  Code[0] := $E9;
  PInteger(@Code[1])^ := Integer(@ServiceController) - Integer(Code) - 5;

  FWrapper := Pointer(Code);

  // проверка
 // FWrapper(100500);
end;


initialization
  CreateExecutableHeap;

finalization
  DestroyExecutableHeap;

end.