[PATCH] resolv/resolv.h: allow alternative resolv.conf files

[Carlos O'Donell]

On 08/17/2017 10:32 AM, Renzo Davoli wrote:
>> _PATH_RESCONF really has to be a string literal, and you can't use a GNU
>> C extension in such a way in an installed header file.
>>
>> The environment variable would have to be ignored in AT_SECURE mode, so
>> you have to use __libc_secure_getenv or put it into unsecvars.h.
> 
> Here is a different implementation:
> * it does not use any gcc extension
> * use __libc_secure_getenv instead of getenv
> * do not change installed header files.

You ask:

"Why to obtain a so simple feature should I have to overlay mount /etc?"

and the answer is:

* It complicates the glibc design when an overlay mount already exists.

* Environment variables are brittle and may be cleared in certain
  or unused in certain circumstances.

The most robust solution is an overlay mount in /etc.

Is there anything technically wrong with the overlay mount?

The overlay mount is semantically clearer than another env var that
changes existing behaviour.

-- 
Cheers,
Carlos.