[PATCH][v3] Add dynamic linker support for $EXEC_ORIGIN.

[Brooks Moses]

On Sun, Mar 30, 2014 at 5:54 PM, Carlos O'Donell <carlos@redhat.com> wrote:
> On 12/23/2013 02:46 PM, Brooks Moses wrote:
> > Updated to include Mike Frysinger's comments, as below.  Mike suggests
> > that this still needs signoff from someone more familiar with the ld.so
> > code; any volunteers?
>
> I've finally worked the patcwork queue down to this path :-)

Thanks!  (And congratulations on getting the queue reduced that much!)

> You're going to end up with at least one more iteration, because I'd
> like to see documentation of $EXEC_ORIGIN in the glibc manual.
[...]

Will do, along with filing the Bugzilla entry as you requested below.

> Why is this what you want? What is wrong with the path encoding effectively
> arbitrary storage data? I still don't see what problem you're trying to
> solve by using $EXEC_ORIGIN. Can you walk me through an example execution
> sequence that shows how you would use this?
>
> I promise you I'm not trying to block this patch for no reason, but
> I have an 8 month old, and I don't get much sleep, so many explanations
> need to be dumbed down for me or explained twice.
>
> Roland has also expressed his worry that we don't really understand the
> problem that this is meant to solve, and I am in agreement for now.

Yup, I fully agree it's a fair request.  I see that Paul has already
replied.  (Thanks, Paul!  I was meaning to get around to it but last
week was a busy week.)

I'll just add that we've been using a variant of this patch internally
for a couple of years now.  I had to rewrite the get_directory
function -- the old one used readlink() to canonicalize the directory
name, and that stopped working in the loader in a recent glibc version
-- but the rest of the patch is pretty much exactly what we've been
using.

The x86_64 testsuite was indeed clean with no regressions when I last
tested it, and I'll reconfirm that after rebasing it and addressing
your comments.

- Brooks