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Date:   Tue, 17 Jan 2023 13:19:19 +0000
From:   Thomas =?utf-8?Q?Wei=C3=9Fschuh?= <thomas@t-8ch.de>
To:     Thomas =?utf-8?Q?Wei=C3=9Fschuh?= <linux@weissschuh.net>,
        Masahiro Yamada <masahiroy@kernel.org>,
        linux-kbuild@vger.kernel.org,
        Amy Parker <apark0006@student.cerritos.edu>
Cc:     linux-kernel@vger.kernel.org
Subject: Re: [PATCH] kheaders: explicitly validate existence of cpio command
Message-ID: <20230117131919.3ywkaptian2y242d@t-8ch.de>
References: <20230117-kernel-kheaders-cpio-v1-1-058d3e1c8621@weissschuh.net>
 <Y8ZgTgtA9oH8W17Y@buildd.core.avm.de>
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On Tue, Jan 17, 2023 at 09:46:02AM +0100, Nicolas Schier wrote:
> On Tue, Jan 17, 2023 at 05:30:43AM +0000, Thomas Wei?schuh wrote:
> > If the cpio command is not available the error emitted by
> > gen_kheaders.so is not clear as all output of the call to cpio is
> > discarded:
> > 
> > GNU make 4.4:
> > 
> >   GEN     kernel/kheaders_data.tar.xz
> > find: 'standard output': Broken pipe
> > find: write error
> > make[2]: *** [kernel/Makefile:157: kernel/kheaders_data.tar.xz] Error 127
> > make[1]: *** [scripts/Makefile.build:504: kernel] Error 2
> > 
> > GNU make < 4.4:
> > 
> >   GEN     kernel/kheaders_data.tar.xz
> > make[2]: *** [kernel/Makefile:157: kernel/kheaders_data.tar.xz] Error 127
> > make[2]: *** Waiting for unfinished jobs....
> > make[1]: *** [scripts/Makefile.build:504: kernel] Error 2
> > 
> > Add an explicit check that will trigger a clear message about the issue:
> > 
> >   CHK     kernel/kheaders_data.tar.xz
> > ./kernel/gen_kheaders.sh: line 17: type: cpio: not found
> 
> Thanks for the patch!  What would you think about an even more verbose
> message?  Perhaps something like:
> 
>     echo >&2 ' *** "cpio" is required for "CONFIG_IKHEADERS". >&2

Wouldn't hurt obviously.
The other scripts used by the kernel don't seem to try to provide this
kind of explicit message either, though.
Having a line number, some sort of "not found" and the name of the
command are enough, in my opinion.

> Reviewed-by: Nicolas Schier <n.schier@avm.de>

Thanks!

Thomas