[Buildroot] [autobuild.buildroot.net] Build results for 2019-06-10

[Thomas Petazzoni]

Hello Sam,

First of all, thanks for the investigation. Adding Atharva, Arnout and
Yann in Cc, since the issue is due to BR2_REPRODUCIBLE=y.

On Wed, 12 Jun 2019 15:33:53 +1000
Sam Bobroff <sbobroff at linux.ibm.com> wrote:

> >  powerpc64le |                    cups-2.2.10 | NOK | http://autobuild.buildroot.net/results/c4e0f6a3c79c9cb083a08f811b7d4838efef50f9 |       
> 
> [snip]
> 
> This failure building cups seems to be caused by an interaction between
> buildroot and the cups package:
> 
> a) Buildroot setting the environment variable "GZIP" to "-n", and
> b) the cups package internally using a Make variable "GZIP" for the path to
> the gzip binary (i.e. "/bin/gzip").
> 
> So, when Make executes the rules for "install-data", the existance of
> GZIP in Make's environment causes it to export it's value of GZIP into
> the environment for the rules. Unfortunately for gzip, which is
> expecting to see command line arguments in $GZIP, it now sees it's own
> path as a command line option and the build fails with:
> 
> gzip: /bin/gzip.gz: Permission denied
> 
> I think the real fix should be in cups, because I *think* what all this
> means is that it's always a bad idea to use a Make variable called
> 'GZIP' and they should rename it there. It fails the same way on the
> master branch of cups so I've filed a bug report on their github issue
> tracker.
> 
> However, it's easy to work around on the buildroot side with a hack in
> the package file:
> CUPS_MAKE_ENV = env -u GZIP
> ... but it does seem a bit cheeky to sneak a call to "env" in there. Is
> there a better way to remove a variable from make's environment?

Dropping the GZIP environment variable is maybe not going to work well
either: the reason why GZIP = -n is because of BR2_REPRODUCIBLE=y. The
-n option of gzip tells gzip to not store the file name and timestamp,
which is necessary for reproducible builds. Of course, it all depends
if the files that are being compressed by the cups build end up on the
target. If they don't, we can live without the -n option. However, if
they end up on the target, we really need to keep the -n option.

Best regards,

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