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Re: Hidden PLT workaround


On Friday 07 May 2010 09:32:48 Ryan Arnold wrote:
> On Fri, May 7, 2010 at 12:44 AM, Boris Arnoux wrote:
> > For example, to "default" around the "write" hidden_proto macro in
> > unistd.h. That way the visibility of the internal "write" symbol is
> > changed from hidden to default.  This approach works well with uclibc
> > for example, and it makes it easy to build a library with overridable
> > symbols. But it does not work in glibc. I don't clearly understand
> > why. Is there another thing making calls to these symbols not go
> > through the PLT , such as an  symbol export map, or something like
> > that ?
>
> Yes, you are close.  There are Versions files which are combined
> during the build stage to create linker scripts which indicate which
> symbols are exported.  Take a look at those.

the Version files control the final list of exported symbols.  it does not 
affect the PLT bypassing when compiling individual files.
-mike

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