Re: [PATCH -tip] x86: headers - fix export private data to userspace

Harvey Harrison
2009-01-13T19:05:26Z

On Tue, 2009-01-13 at 10:49 -0800, H. Peter Anvin wrote:
> Harvey Harrison wrote:
> > On Tue, 2009-01-13 at 21:34 +0300, Cyrill Gorcunov wrote:
> >> Impact: cleanup
> >
> >> 4) setup.h - COMMAND_LINE_SIZE saved for userspace, bootloaders
> >> could use it.
> >
> > Doesn't this need to be (at least) _COMMAND_LINE_SIZE to avoid
> > polluting the namespace, not sure it can be changed though as the
> > horse is already out of the barn.
>
> No, this is not one of those cases, but it's worth explaining why.
>
> You can introduce symbols into the general namespace if *and only if*
> they are in a header file that is invoked directly by the user. In
> other words, such a header file is unusable by libc, but setup.h doesn't
> contain anything needed by libc in the first place.
>

Thanks for the explanation, while I was aware of that, I hadn't actually
looked if libc pulled this in...thinking a bit more it should have been
obvious libc wouldn't be interested in this header.

Thanks.

Harvey