[omniORB] Location Marshalling Fault

[Duncan Grisby]

On Monday 21 July, "EXT-Pennington, Dale K" wrote:

> They are placing arbitrary values into enumated members of a CORBA IDL
> derived structure and passing it through the CORBA interface. These
> values fail the sanity check in the generated .hh files while
> unmarshalling in the server, hence causing the CORBA MARSHALLING
> exception to be passed back to the client.

That is definitely an invalid thing to do. The only permitted values for
an enum are the ones implied by the enum's definition in IDL. Sending
any other numeric value is an error, and it's right for omniORB to throw
an exception.

It is a coincidence that the C++ mapping to C++ enum permits numeric
values other than the enum values -- other language mappings, for
example Python, use symbolic names for the enum values, and cannot
possibly support values outside those in the IDL.

> Now we are in no position to change how the existing app does things.
> Also what they do gets by their ORB (as well as TAO orb, which we are
> also evaluating) with no complaints. Sanity checking seems unique to
> OmniORB at this point.

omniORB is often more strict about following the specifications than
other ORBs.

> The next question on my list is : Is there a way to disable the sanity
> checking in the enumation unmarshalling code, other than manually
> editing the .hh files generated by the IDL Compiler. I read the IDL
> chapter of the documentation, and did not see anything.

There's no omniidl switch, and I don't think it's good to add one and
encourage people to do invalid things like this. That said, it's really
easy for you to modify the omniidl back-end to remove the checking code.
Look at src/lib/omniORB/omniidl_be/cxx/header/template.py, line 1577, in
the definition of enum_operators. If you edit that to remove the check,
that will prevent it being generated.

If you don't fancy that approach, the other thing you can do is change
the IDL to use an unsigned long instead on an enum. As long as the
values aren't put inside Anys, the marshalled form will be identical.

Cheers,

Duncan.

-- 
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