How do I detect whether I'm installing on a Terminal Server in an InnoSetup script?

Question

My setup should behave slightly differently when the program is installed on a Terminal Server. I know about GetSystemMetrics(SM_REMOTESESSION) but as far as I understood that will only tell me whether I'm running inside a RDP session. It would not catch the case where the server admin is logged on locally to install software, or would it?

Checking for the Terminal Server service does not appear to be viable either as that also runs on workstations when Remote Desktop has been enabled. I need to differentiate this from a true TS that allows multiple concurrent logon sessions.

Isn't there any other service or registry key that I check for?

Answer 1

This is exactly what you need:

Detecting Whether Terminal Services Is Installed

Note that in addition to this you can use the value of GetVersion() to determine if you are at all running NT. If not NT then bail out.

// Are we running Windows NT?
DWORD dwVersion = GetVersion();
if (!(dwVersion & 0x80000000)) {
    // Is it Windows 2000 or greater?
    if (LOBYTE(LOWORD(dwVersion)) > 4) {
        // Check with VerSetConditionMask() and VerifyVersionInfo()
        return ..;
    }
    else  {
        // Windows NT 4.0 or earlier. Check ProductSuite value in
        // HKLM\\System\\CurrentControlSet\\Control\\ProductOptions
        return ..;
    }
}

return false;

The link shows the code you need to query if the version is Win2k or later

Answer 2

I'm guessing that this question has a potential for many answers, all of which will seem slightly unsatisfactory.

For instance, what are the possible scenarios:

• Workstation, with RDP enabled (ie. XP with remote help enabled)
• Server, with RDP enabled (easily distinguishable from a workstation by checking the OS type)

However, what about a server that has the RDP option enabled, but it isn't used? How about a server that has the RDP option enabled, but the administrator is installing your software at the console, at a time of day when nobody is logged in through RDP? You wouldn't be able to determine if the server is actually in use, RDP-wise, or not.

The best way to give you a concrete answer is to ask why you need to determine this? What kind of functionality will you enable or disable if you were able to reliably detect this?

Answer 3

Thanks to the link provided by Magnus Skog I discovered that InnoSetup already supports the GetWindowsVersionEx API function. Therefore all I had to do was this:

function IsRunningOnTS: Boolean;
var
  lWinVer: TWindowsVersion;
begin
  GetWindowsVersionEx(lWinVer);
  Result := (lWinVer.SuiteMask and VER_SUITE_TERMINAL) <> 0;
end;

I have successfully tested this for the following scenarios:

• logged on locally to an XP workstation with RDP enabled (returns False)
• logged on remotely to a Terminal Server via RDP (returns True)
• logged on remotely to a workstation via RDP (returns False)

I did not yet have the opportunity to test while logged on locally on a TS. Will update this post when I have.