kbuild: Improve portability of some sed invocations

* Use BREs where EREs aren't necessary.
* Pass -E instead of -r to use EREs. This will be standardized in the
  next POSIX revision[0]. GNU sed supports this since 4.2 (May 2009),
  and busybox since 1.22.0 (Jan 2014).
* Use the [:space:] character class instead of ` \t` in bracket
  expressions. In bracket expressions, POSIX says that <backslash> loses
  its special meaning, so a conforming implementation cannot expand \t
  to <tab>[1].
* In BREs, use interval expressions (\{n,m\}) instead of non-standard
  features like \+ and \?.
* Use a loop instead of -s flag.

There are still plenty of other cases of non-standard sed invocations
(use of ERE features in BREs, in-place editing), but this fixes some
core ones.

[0] http://austingroupbugs.net/view.php?id=528
[1] http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html#tag_09_03_05

Signed-off-by: Michael Forney <forney@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
This commit is contained in:
Michael Forney 2018-02-06 22:41:17 -08:00 committed by Masahiro Yamada
parent ae0c553c24
commit 1fe7d2bb24
5 changed files with 11 additions and 9 deletions

View file

@ -194,7 +194,7 @@ input_file() {
source="$1"
if [ -f "$1" ]; then
${dep_list}header "$1"
is_cpio="$(echo "$1" | sed 's/^.*\.cpio\(\..*\)\?/cpio/')"
is_cpio="$(echo "$1" | sed 's/^.*\.cpio\(\..*\)\{0,1\}/cpio/')"
if [ $2 -eq 0 -a ${is_cpio} = "cpio" ]; then
cpio_file=$1
echo "$1" | grep -q '^.*\.cpio\..*' && is_cpio_compressed="compressed"