[Buildroot] [Bug 7172] Name collision of rpath token expansion and internal variables

[Mike Zick <minimod@morethan.org>]

On Sun,  8 Jun 2014 07:03:29 +0000 (UTC)
bugzilla at busybox.net wrote:

> https://bugs.busybox.net/show_bug.cgi?id=7172
> 
> --- Comment #1 from Samuel Martin <s.martin49@gmail.com> 2014-06-08
> 07:03:28 UTC --- Mike,
> 
> (In reply to comment #0)
> > Ref:  man ld.so
> > 
> > Example:
> > In menu -> tool chain -> Target Linker Options (BR2_TARGET_LDFLAGS)
> > to: -Wl,-rpath='$ORIGIN/../lib'
> > (A relative path from executable to pathname of its required
> > libraries. The example in ld.so manual.).
> > 
> > Build BusyBox (which honors BR_TARGET_LDFLAGS, not everything does).
> > 
> > Use: readelf -dl on the resulting binary and find an entry similar
> > to: 0x0000000f (RPATH)                      Library rpath:
> > [outputRIGIN/../lib]
> > 
> > Where the $O of $ORIGIN has been expanded to an internal value by
> > the time the content of BR2_TARGET_LDFLAGS is seen by the compiler.
> 
> Unfortunately, there is no trivial solution. This bug comes from the
> interaction between Buildroot and the packages' build-systems
> (especially those based on autotools).
> 
> I mean there no easy way to correctly escape "$ORIGIN" in makefiles
> (form Buildroot and the package itself) or/and in sh scripts.
> 

Grumble.
But I half-way expected that finding.
;)

> > 
> > This was when using the Buildroot generation of a toolchain.
> > Other toolchain selections not tested.
> 
> The toolchain has nothing to do with this issue.
> 
> 
> From the couple of experiments I run, the only reliable solution to
> correctly set RPATH is using chrpath or patchelf at the end of the
> build.
> 

That (patchelf ref:
http://anonscm.debian.org/gitweb/?p=collab-maint/patchelf.git;a=summary
http://nixos.org/patchelf.html)
was going to be my 'temporary' work-around.

Along with a post-build script to munge things as required.

Not so temporary now I guess.

- - - -

There is an alternative, for people who only need a very few
binaries built - -
Set 'Target Linker Options' to a long string, longer than they
will need, and after build hex-edit the binaries to the required 
string.

But that gets tiring real soon.  ;)
And some packages are ignoring 'Target Linker Options' anyway.
So even with this method, people would still need patchelf.

- - - -

Hmm...
I guess I should add a selection to build host-patchelf to BR.
Someone else out there might need it, even if they don't need
ld.so token expansion in runpath and/or rpath.

Thanks for taking the time to check this out.
Might have to mark it as: "Can't be fixed" in the bug tracker.

Mike
> 
> Regards,
> 
> Samuel
>