Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <20191021145137.31672-1-jeyu@kernel.org> <20191021160419.28270-1-jeyu@kernel.org>
In-Reply-To: <20191021160419.28270-1-jeyu@kernel.org>
From:   Masahiro Yamada <yamada.masahiro@socionext.com>
Date:   Tue, 22 Oct 2019 13:37:47 +0900
Message-ID: <CAK7LNASyGSVNoKDqbtJYs+s-PRz3cqfet779M+PEWoAFu4e2TA@mail.gmail.com>
Subject: Re: [PATCH v2] scripts/nsdeps: use alternative sed delimiter
To:     Jessica Yu <jeyu@kernel.org>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Matthias Maennich <maennich@google.com>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Tue, Oct 22, 2019 at 1:05 AM Jessica Yu <jeyu@kernel.org> wrote:
>
> When doing an out of tree build with O=, the nsdeps script constructs
> the absolute pathname of the module source file so that it can insert
> MODULE_IMPORT_NS statements in the right place. However, ${srctree}
> contains an unescaped path to the source tree, which, when used in a sed
> substitution, makes sed complain:
>
> ++ sed 's/[^ ]* *//home/jeyu/jeyu-linux\/&/g'
> sed: -e expression #1, char 12: unknown option to `s'
>
> The sed substitution command 's' ends prematurely with the forward
> slashes in the pathname, and sed errors out when it encounters the 'h',
> which is an invalid sed substitution option. To avoid escaping forward
> slashes in ${srctree}, we can use '|' as an alternative delimiter for
> sed to avoid this error.
>
> Signed-off-by: Jessica Yu <jeyu@kernel.org>
> ---
>
> This is an alternative to my first patch here:
>
>   http://lore.kernel.org/r/20191021145137.31672-1-jeyu@kernel.org
>
> Matthias suggested using an alternative sed delimiter instead to avoid the
> ugly/unreadable ${srctree//\//\\\/} substitution.
>
>  scripts/nsdeps | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/scripts/nsdeps b/scripts/nsdeps
> index 3754dac13b31..63da30a33422 100644
> --- a/scripts/nsdeps
> +++ b/scripts/nsdeps
> @@ -33,7 +33,7 @@ generate_deps() {
>         if [ ! -f "$ns_deps_file" ]; then return; fi
>         local mod_source_files=`cat $mod_file | sed -n 1p                      \
>                                               | sed -e 's/\.o/\.c/g'           \
> -                                             | sed "s/[^ ]* */${srctree}\/&/g"`
> +                                             | sed "s|[^ ]* *|${srctree}\/&|g"`


You no longer need to escape the '/'.

s|[^ ]* *|${srctree}/&|g

is enough.


BTW, connecting multiple sed commands with pipes
is not efficient.


sed -n 1p | sed -e 's/\.o/\.c/g'

can be replaced with

sed -n '1s/\.o/\.c/gp'


This script can be improved a whole
if somebody is interested in the refactoring.


>         for ns in `cat $ns_deps_file`; do
>                 echo "Adding namespace $ns to module $mod_name (if needed)."
>                 generate_deps_for_ns $ns $mod_source_files
> --
> 2.16.4
>


-- 
Best Regards
Masahiro Yamada