Re: [PATCH v2] libio: use PTR_MANGLE/PTR_DEMANGLE for FILE vtables

[Mike Frysinger <vapier at gentoo dot org>]

On 01 Oct 2015 15:27, Kees Cook wrote:
> On Thu, Oct 1, 2015 at 2:41 PM, Joseph Myers wrote:
> > On Thu, 1 Oct 2015, Kees Cook wrote:
> >> On Thu, Oct 1, 2015 at 2:00 PM, Joseph Myers wrote:
> >> > On Thu, 1 Oct 2015, Florian Weimer wrote:
> >> >> Even better, if we can grab a few old binaries and they do not run on
> >> >> current systems for other libstdc++-related reasons (or perhaps we
> >> >
> >> > The libstdc++ SONAME changed in GCC 3.4, so any relevant binaries will be
> >> > using an old libstdc++ shared library (or possibly statically linked with
> >> > libstdc++ but dynamically linked with libc).
> >>
> >> So system without ancient static binaries and no libstdc++-v3 or
> >> earlier should be safe for this change? When did v4 happen? Seems like
> >> a long time ago?
> >
> > It's still libstdc++-v3 even though it's gone through multiple SONAMEs
> > (it's been v3 since GCC 3.0).  The question is libstdc++.so.5 or older -
> > or dynamically linked binaries from compilers of that vintage with
> > libstdc++.a linked in.
> 
> Okay, so, since roughly 2007? Should I name the config "--only-v6+" or
> something?

i wouldn't make it opaque.  just call it something like "libio-file-ptr-mangle".
then in the documentation, describe the possible limitations.
-mike

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