[PATCH] Add getrandom implementation [BZ #17252]

[Joseph Myers]

On Fri, 10 Jun 2016, Joseph Myers wrote:

> > +  # We use a dedicated symbol version so that we can scan the
> > +  # .gnu.version_r section to identify binaries which use the
> > +  # getrandom function.  This allows us to avoid lazy opening of the
> > +  # emulation file descriptors if this proves too error-prone.
> 
> I understand this even less than the other safeguards.  Why is this 
> different from all other functions?  What is "us"?  I don't see any 
> special dynamic linker code to check for this version, for example.

And, what happens to this version for new ports where GLIBC_2.25 or later 
is the minimum symbol version?  And what inheritance relations does it 
have with other symbol versions (not that I'm clear on what significance 
the inheritance relations actually have)?

Versioning a symbol in a way different from all our other symbol 
versioning seems high-risk and needs a compelling justification.

-- 
Joseph S. Myers
joseph@codesourcery.com