Run an application under a specific user account

program RunButAs;

{$APPTYPE CONSOLE}

{$R *.res}

uses
  Windows,
  SysUtils;

var
  User, Password, Params : WideString;
  sUser, sPassword : string;

function CreateProcessWithLogonW(
  lpUsername : LPCWSTR;
  lpDomain : LPCWSTR;
  lpPassword : LPCWSTR;
  dwLogonFlags : DWORD;
  lpApplicationName : LPCWSTR;
  lpCommandLine : LPWSTR;
  dwCreationFlags : DWORD;
  lpEnvironment : pointer;
  lpCurrentDirectory : LPCWSTR;
  var lpStartupInfo : TStartupInfoW;
  var lpProcessInfo : TProcessInformation
  ) : boolean; stdcall; external 'Advapi32.dll';

procedure ShowHelp;
begin
  writeln('Run an application under a specific user account');
  writeln('Copyright (c) 2009, Serhiy Perevoznyk');
  writeln;
  writeln('Usage : ' + ExtractFileName(ParamStr(0)) + ' <user name=""> [<password>] <command line="">');
  halt(1);
end;

const LOGON_WITH_PROFILE = 1;

var
 si : TStartupInfoW;
 pi : TProcessInformation;
 hUserToken: THandle;
begin
  try
    if ParamCount < 2 then
     ShowHelp;

     if ParamCount = 2 then
       begin
         user := ParamStr(1);
         suser := ParamStr(1);
         Password := '';
         sPassword := '';
         Params := ParamStr(2);
       end
        else
          if ParamCount = 3 then
            begin
               user := ParamStr(1);
               Password := ParamStr(2);
               suser := ParamStr(1);
               sPassword := ParamStr(2);
               Params := ParamStr(3);
            end
              else
                ShowHelp;

     FillChar(si, sizeof(si), 0);
     FillChar(pi, sizeof(pi), 0);

    if not LogonUser(PChar(suser), nil, PChar(spassword),
      LOGON32_LOGON_INTERACTIVE, LOGON32_PROVIDER_DEFAULT, hUserToken) then
     begin
       writeln('Wrong user name or password');
       halt;
     end; 

     CreateProcessWithLogonW(PWideChar(user), nil, PWideChar(password), LOGON_WITH_PROFILE,
     nil, PWideChar(Params), CREATE_UNICODE_ENVIRONMENT, nil, nil, si, pi);

  except
    on E:Exception do
      Writeln(E.Classname, ': ', E.Message);
  end;
end.