Re: [PATCH] #13594: Avoid race in nscd

[Roland McGrath <roland at hack dot frob dot com>]

> > Why are we rolling a bespoke pthread_spin_lock()?
> >
> > If we have threads, why aren't we using the pthreads interface?
> 
> The handle is already in the code and used this way, so we're compatible.

There may be just some hysterical raisins here.  But the important thing to
note is that this is a shared-memory area shared between nscd itself and
arbitrary programs using libc.  The latter might not have any pthread code,
so for name space reasons if nothing else it couldn't literally use
pthread_spin_lock.

But more generally, the nscd shared-memory area is in effect another ABI
surface.  So everything that makes it more straightforwardly self-contained
simplifies the potential compatibility issues.


Thanks,
Roland