ATL bug with per user registration of COM component

From:

stuflee@googlemail.com

Newsgroups:

microsoft.public.vc.atl

Date:

Thu, 5 Feb 2009 06:51:34 -0800 (PST)

Message-ID:

<2b5f92cf-846f-4c01-a54a-c59a433155b3@q36g2000vbn.googlegroups.com>

I have an exe which I am registering as a COM component. This runs
out of process with an Excel session. Historically we have been
installing this as a machine level component but this causes issues as
it requires administrator access. Recently we began investigating per
user registration but there seems to be a bug in atlbase.h that is
preventing it.

We are deriving our application class from CAtlExeModuleT, which takes
responsibility for the command line parsing and the class
registration.

When doing this as a permissoned user we have no issue doing machine
wide registration, into HKEY_LOCAL_MACHINE. However, when we run this
as either a permissoned user or a user that has no write access to
HKEY_LOCAL_MACHINE the registration fails silently.

I've tracked this down to a method on a class in atlbase.h,
ATL::CAtlServiceModuleT<T,nServiceNameID>::RegisterAppId, which always
attempts to write the registry key to HKCR. When per user
registration is set, via AtlSetPerUserRegistration, this fails.

MSDN states:

=93To change the settings for the interactive user, store the changes
under KEY_CURRENT_USER\Software\Classes rather than
HKEY_CLASSES_ROOT.=94

So, it seems as if the registration code in the ATL library is not
correctly handling this flag, and the fix is simply to redirect to the
current user registry space based upon the result of
AtlGetPerUserRegistration(). I fancy this shouldn't be necessary but
experimentation has demonstrated that this change is sufficient and
necessary.

Has anyone encountered this problem and is there and 'official' fix or
a workaround available that doesn't involving hacking atlbase.h?

<snip>
        CRegKey keyAppID;
        LONG lRes = keyAppID.Open(HKEY_CLASSES_ROOT, _T("AppID"),
KEY_WRITE);
        if (lRes != ERROR_SUCCESS)
            return AtlHresultFromWin32(lRes);

</snip>

becomes:

<snip>
        CRegKey keyAppID;
        bool isPerUser;
        AtlGetPerUserRegistration(&isPerUser);
        if (lRes != ERROR_SUCCESS)
            return AtlHresultFromWin32(lRes);

        LONG lRes;
        if (isPerUser == true)
        {
            //Bug in atlbase.h!!!!!
            lRes = keyAppID.Open(HKEY_CURRENT_USER, _T("Software\\Classes\
\AppID"), KEY_WRITE);
        }
        else
        {
            lRes = keyAppID.Open(HKEY_CLASSES_ROOT, _T("AppID"), KEY_WRITE);
        }
        if (lRes != ERROR_SUCCESS)
            return AtlHresultFromWin32(lRes);
</snip>