Messages in this thread |  | | From | Masahiro Yamada <> | Date | Sun, 25 Dec 2022 01:45:52 +0900 | Subject | Re: [PATCH] kheaders: prefer gtar over tar for better compatibility |
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On Sat, Dec 17, 2022 at 5:42 PM Michał Górny <mgorny@gentoo.org> wrote: > > Commit 86cdd2fdc4e39c388d39c7ba2396d1a9dfd66226 ("kheaders: make headers > archive reproducible") introduced a number of options specific to GNU > tar to the `tar` invocation in `gen_kheaders.sh` script. This causes > the script to fail to work on systems where `tar` is not GNU tar. This > can occur e.g. on recent Gentoo Linux installations that support using > bsdtar from libarchive instead. > > To achieve better portability, try using `gtar` over `tar` if the former > is available. This is the name frequently used on systems featuring > support for installing GNU tar alongside another tar implementation. > If `gtar` is not present, `tar` is used for compatibility with regular > systems. > > Link: https://bugs.gentoo.org/884061 > Reported-by: Sam James <sam@gentoo.org> > Tested-by: Sam James <sam@gentoo.org> > Signed-off-by: Michał Górny <mgorny@gentoo.org> > --- > kernel/gen_kheaders.sh | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/kernel/gen_kheaders.sh b/kernel/gen_kheaders.sh > index 473036b43..d2445af7f 100755 > --- a/kernel/gen_kheaders.sh > +++ b/kernel/gen_kheaders.sh > @@ -80,11 +80,20 @@ done | cpio --quiet -pdu $cpio_dir >/dev/null 2>&1 > find $cpio_dir -type f -print0 | > xargs -0 -P8 -n1 perl -pi -e 'BEGIN {undef $/;}; s/\/\*((?!SPDX).)*?\*\///smg;' > > +# The following tar invocations use options specific to GNU tar. On some > +# systems (e.g. Gentoo), `tar` can be a different tool (e.g. bsdtar), and GNU > +# tar can be found as `gtar`. > +if [ -x "$(command -v gtar)" ]; then > + tar=gtar > +else > + tar=tar > +fi > + > # Create archive and try to normalize metadata for reproducibility. > # For compatibility with older versions of tar, files are fed to tar > # pre-sorted, as --sort=name might not be available. > find $cpio_dir -printf "./%P\n" | LC_ALL=C sort | \ > - tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \ > + $tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \ > --owner=0 --group=0 --numeric-owner --no-recursion \ > -I $XZ -cf $tarfile -C $cpio_dir/ -T - > /dev/null
I checked the options in bsd tar [1].
Presumably, there is no way to make it work for both due to incompatible options (--owner vs --uid, --group vs --gid).
Instead of inserting a workaround like this, another way is to allow users to override a variable from the command line.
See the top Makefile, for example,
AWK = awk
Then, users can do "make AWK=gawk"
[1] https://www.freebsd.org/cgi/man.cgi?tar(1)
> -- > 2.39.0 >
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