[Buildroot] [git commit] package/patchelf: keep RPATH entries even without DT_NEEDED libraries

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

On Tue, 25 Aug 2020 18:16:59 +0200
"Yann E. MORIN" <yann.morin.1998@free.fr> wrote:

> > -+            if (!libFoundInRPath(canonicalPath, neededLibs, neededLibFound)) {
> > -+                debug("removing directory '%s' from RPATH because it does not contain needed libs\n",
> > -+                      dirName.c_str());
> > -+                continue;  
> 
> I'd rather that we keep that as a warning, because in some cases it
> really is an error to keep an RPATH with no DT_NEEDED.
> 
>     debug("keeping directory %s in RPATH, even though it contains no needed library\n", dirName.c_str())

Such debug() messages are not even printed by default, only when you
pass --debug to patchelf. So essentially in the context of Buildroot,
those messages would never be seen. With that information, does it
still make sense ?

Also, it would IMO still be wrong to output a warning. Having a RPATH
to resolve dlopen() library paths is a perfectly valid and legitimate
situation, there is nothing to warn about. Excessive warnings make
warnings useless I believe.

See the dlopen() man page where they explain how dlopen() behaves when
the library path doesn't start with a /.

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com