[PATCH v7 1/4] Add system-wide tunables: ldconfig part

[Florian Weimer]

* DJ Delorie:

> Adds support for reading /etc/tunables.conf

Shouldn't this go into /etc/glibc?

> The file contains one line per tunable, like this:
>
> glibc.foo.bar=14
> glibc.malloc.more=0
>
> Additionally, each line can be prefixed with a single character
> that controls overridability by the GLIBC_TUNABLES env var:
>
> !glibc.foo=0
>    ^ May be made more secure
> +glibc.foo=0
>    ^ May be overridden
> -glibc.foo=0
>    ^ May not be overridden

Can we please use keywords, like in the existing ld.so.conf file?
We still have "include".  We used to have "hwcap".

I'm also not convinced that having a separate file hard-coded into
ldconfig is a good idea.  People will to teach their management tools
about it (where they currently handle /etc/ld.so.conf.d).  It's also not
really compatible with this request:

  Bug 2440274 - Source ld.so configs drop-ins from /usr/lib
  <https://bugzilla.redhat.com/show_bug.cgi?id=2440274>

In addition to /usr/lib/ld.so.conf.d/, we'd need
/usr/lib/tunables.conf.d/ (or presumably something with glibc in it).

On the other hand, FreeBSD's libmap.conf
<https://man.freebsd.org/cgi/man.cgi?query=libmap.conf> is more like the
tunables.conf approach you are proposing.

Thanks,
Florian