[Nix-dev] Re: libgmp impurity

[Ludovic Courtès]

Hi,

Peter Simons <simons at cryp.to> writes:

> the gmp library performs rather sophisticated compiler-flag guessing in
> its configure script. When run on my system, for instance, it configures
> itself as follows:

Yes, it has a custom `config.guess', which reports the exact
sub-architecture supported (unlike the "normal" `config.guess' that's
used by other GNU projects).

The impurity actually stems from syscalls like uname(2), which leak
information about the underlying kernel.  This breaks the Nix model
because the kernel is not an explicit build input of user applications.

There's no simple solution for this, I'm afraid.  ptrace(2)?  :-)

Thanks,
Ludo'.