Re: [PATCH v2 2/2] scripts: headers_install: avoid extra sed call for license check

[Nicolas Schier <nsc@kernel.org>]

[Cc+=nathan]

On Thu, Jan 08, 2026 at 07:39:43AM +1100, David Disseldorp wrote:
> headers_install runs a sed script to check that any GPL variant
> SPDX-License-Identifier line carries a "WITH Linux-syscall-note".
> A subsequent sed invocation then handles removal of a few things that
> aren't desired in installed headers (e.g. __attribute_const__).
> 
> Combine these two sed scripts to avoid re-processing the same file.
> License check errors, as opposed to write errors, are indicated via a
> special sed exit status of 9.
> 
> Signed-off-by: David Disseldorp <ddiss@suse.de>
> ---
>  scripts/headers_install.sh | 19 ++++++++++++-------
>  1 file changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/scripts/headers_install.sh b/scripts/headers_install.sh
> index 2181abd1c9b70..ef952cbbb8fde 100755
> --- a/scripts/headers_install.sh
> +++ b/scripts/headers_install.sh
> @@ -23,20 +23,25 @@ TMPFILE=$OUTFILE.tmp
>  
>  trap 'rm -f $OUTFILE $TMPFILE' EXIT
>  
> -# SPDX-License-Identifier with GPL variants must have "WITH Linux-syscall-note"
> -if [ -n "$(sed -n -e "/SPDX-License-Identifier:.*GPL-/{/WITH Linux-syscall-note/!p}" $INFILE)" ]; then
> -	echo "error: $INFILE: missing \"WITH Linux-syscall-note\" for SPDX-License-Identifier" >&2
> -	exit 1
> -fi
> -
> +# returns 9 if GPL SPDX-License-Identifier omits "WITH Linux-syscall-note"
>  sed -E -e '
> +	/SPDX-License-Identifier:.*GPL-/{/WITH Linux-syscall-note/! Q9}

thanks, I like the idea of combining the sed calls.  According to the
manual 'Q' (or 'q' with argument) is a GNU extension (non-POSIX).

May we expect GNU sed on all system running headers_install?

>  	s/([[:space:](])(__user|__force|__iomem)[[:space:]]/\1/g
>  	s/__attribute_const__([[:space:]]|$)/\1/g
>  	s@^#include <linux/compiler.h>@@
>  	s/(^|[^a-zA-Z0-9])__packed([^a-zA-Z0-9_]|$)/\1__attribute__((packed))\2/g
>  	s/(^|[[:space:](])(inline|asm|volatile)([[:space:](]|$)/\1__\2__\3/g
>  	s@#(ifndef|define|endif[[:space:]]*/[*])[[:space:]]*_UAPI@#\1 @
> -' $INFILE > $TMPFILE || exit 1
> +' $INFILE > $TMPFILE
> +case $? in
> +9)
> +	echo "error: $INFILE: missing \"WITH Linux-syscall-note\" for SPDX-License-Identifier" >&2
> +	exit 1
> +	;;
> +1)
> +	exit 1
> +	;;
> +esac

This silently ignores all other exit codes.  What about this:

9)
...
	;;
0)	;;
*)
	exit 1
	;;
esac


Kind regards,
Nicolas