Re: [PATCH] scripts/config: allow "O=config-dir" option

[Nicolas Schier <nicolas@fjasle.eu>]

On Sat, Oct 30, 2021 at 11:33:22PM -0700, Randy Dunlap wrote:
> Support "O=config-dir" as the location of the .config file
> like (some) other kernel build (make) tools do.
> 
> Someone asked for this "feature" a few months ago but I don't
> recall who it was.
> 
> Also check for the existence of the config-dir/config-file
> and report if there is no such file instead of letting grep
> report that there is no such file.
> 
> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> Cc: Masahiro Yamada <masahiroy@kernel.org>
> Cc: Nick Desaulniers <ndesaulniers@google.com>
> Cc: linux-kbuild@vger.kernel.org
> Cc: Andi Kleen <ak@linux.intel.com>
> ---
>  scripts/config |   44 +++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 39 insertions(+), 5 deletions(-)
> 
> --- linux-next-20211029.orig/scripts/config
> +++ linux-next-20211029/scripts/config
> @@ -37,6 +37,7 @@ commands:
>  
>  options:
>  	--file config-file   .config file to change (default .config)
> +	O=config-dir         Specify the directory location of the config-file
>  	--keep-case|-k       Keep next symbols' case (dont' upper-case it)
>  
>  $myname doesn't check the validity of the .config file. This is done at next
> @@ -124,15 +125,48 @@ undef_var() {
>  	txt_delete "^# $name is not set" "$FN"
>  }
>  
> -if [ "$1" = "--file" ]; then
> -	FN="$2"
> -	if [ "$FN" = "" ] ; then
> +DIR=
> +FN=
> +
> +while [ "$DIR" = "" -o "$FN" = "" ]; do

shellcheck recommends to use [ .. ] || [ .. ] instead of [ .. -o .. ].

> +
> +	if [ "$1" = "" ] ; then
>  		usage
>  	fi
> -	shift 2
> -else
> +	if [ "$1" = "--file" ]; then
> +		FN="$2"
> +		if [ "$FN" = "" ] ; then
> +			usage
> +		fi
> +		shift 2
> +		continue
> +	fi
> +
> +	optn=$1
> +	optnlen=${#optn}
> +	if [ $optnlen -gt 1 ] && [ ${optn:0:2} = "O=" ]; then
> +		DIR=${optn:2}
> +		shift
> +		if [ "$DIR" = "" ]; then
> +			usage
> +		fi
> +		continue
> +	fi
> +	break	# something other than --file or O=dir
> +done
> +
> +if [ "$FN" = "" ]; then
>  	FN=.config
>  fi
> +if [ "$DIR" != "" ]; then
> +	DIR=$DIR"/"
> +fi
> +FN="$DIR""$FN"

A bike shed colour thing: I'd prefer quotes around the complete right
hand side, e.g. "${DIR}/${FN}".

> +
> +if [ ! -r $FN ]; then
             ^^^
$FN needs quotes, otherwise it may lead to syntax errors, e.g. if FN
contains spaces or other syntactical things.

I do like that feature!

With quotes round $FN:
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

> +	echo "No such config file: $FN"
> +	exit
> +fi
>  
>  if [ "$1" = "" ] ; then
>  	usage