Ping^6: [PATCH][v3] Add dynamic linker support for $EXEC_ORIGIN.

[Brooks Moses]

On Fri, Mar 21, 2014 at 12:59 PM, Roland McGrath <roland@hack.frob.com> wrote:
> The implementation is less of the issue here than making the case for the
> feature.

Certainly.  I explained the case for the feature in my initial
description of the patch (and I'll requote that below); I'm not clear
if you didn't see that, or if you're implying that it needs more
elaboration and/or stronger justification.  Could you clarify?  I'm
happy to elaborate if that's what you're asking for.

I wrote:
> The $ORIGIN rpath token expands to the directory containing the true
> copy of the application executable -- which is to say, if the executable
> is invoked through a symlink, that symlink will be resolved in the
> $ORIGIN substitution.
>
> In some cases, such as symlink farms backed by cloud storage filesystems
> where the resolved path encodes effectively-arbitrary storage data, it
> is much more useful to have a rpath token that points to the
> non-expanded, as-called version of the executable path.  This patch adds
> the $EXEC_ORIGIN token for this purpose, resolving to the executable
> path as passed to execve().

Thanks,
- Brooks