[Buildroot] [PATCH v7 5/9] core: sanitize RPATH in host tree at the very end of the build

[Thomas Petazzoni]

Hello,

On Thu, 20 Jul 2017 15:58:49 +0200, Arnout Vandecappelle wrote:

> >>  Also, host-finalize (or sdk) should depend on toolchain, and probably also on
> >> $(filter host-%,$(PACKAGES)). The latter is currently incomplete, but when we
> >> get around to selecting BR2_PACKAGE_HOST_* for all host packages, we will make
> >> sure that 'make sdk' really generates the complete sdk.  
> > 
> > For the SDK, you also need to build all the target packages. The SDK
> > contains the sysroot (i.e STAGING_DIR), where the target packages
> > install libraries and headers.  
> 
>  This is what I wrote in an earlier reply to Wolfgang.

Yes, I was replying as I was reading the thread, and saw your other
reply afterwards.

> > Basically, sdk needs to depend on "world".  
> 
>  Not really, it doesn't need to depend on target-finalize or the rootfs targets.

Correct, but I am not sure it is really worth being smart here.

> >>  And finally, I think that the staging sanitization fits better here than in
> >> target-finalize. It has nothing to do with target, and the only reason that we
> >> do such sanitization is to make the sdk relocatable.  
> > 
> > The sanitization in staging and target has nothing to do with making
> > the SDK relocatable. Why do you think it's related ?  
> 
>  target indeed has nothing to do with making the SDK relocatable. It is only
> needed to deal with stupid packages that don't correctly use --prefix/DESTDIR
> and that end up putting the full absolute build-time directory in rpath.

Agreed.

>  staging is different. Sanitizing staging is not really needed, in the sense
> that any rpath in there is simply not going to be used. We want to sanitize
> staging for the following reasons:
> 
> - To avoid leaking references to the original output directory. This way, we can
> validate that the SDK is relocatable by running a simple "grep -r ${BASE_DIR}
> ${HOST_DIR}". Obviously RPATH sanitization is not sufficient (e.g. also the
> references to source files have to be stripped), but it's a step in the right
> direction. This reason is obviously only relevant for the SDK.
> 
> - To make sure that when an executable is copied to target that it actually
> executes correctly. Since within Buildroot we never copy stuff from staging to
> target, this is clearly only relevant for the SDK.

OK, makes sense. I indeed believe having those details in the commit
log or in the code would be nice.

So do we agree that:

 - target sanitization will be done in target-finalize

 - staging sanitization will be done in "make sdk"

 - host sanitization will be done in "make sdk"

Correct ?

Thanks,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com