From: "Michał Górny" <mgorny@gentoo.org>
To: Dmitry Goldin <dgoldin+lkml@protonmail.ch>
Cc: "Masahiro Yamada" <yamada.masahiro@socionext.com>,
	linux-kernel@vger.kernel.org, "Michał Górny" <mgorny@gentoo.org>,
	"Sam James" <sam@gentoo.org>,
	"Masahiro Yamada" <masahiroy@kernel.org>
Subject: [PATCH v2] kheaders: make it possible to override TAR
Date: Wed, 12 Apr 2023 10:27:43 +0200	[thread overview]
Message-ID: <20230412082743.350699-1-mgorny@gentoo.org> (raw)
In-Reply-To: <CAK7LNATfrxu7BK0ZRq+qSjObiz6GpS3U5L=12vDys5_yy=Mdow@mail.gmail.com>

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.

Add a `TAR` make variable to make it possible to override the tar
executable used, e.g. by specifying:

  make TAR=gtar

Link: https://bugs.gentoo.org/884061
Reported-by: Sam James <sam@gentoo.org>
Tested-by: Sam James <sam@gentoo.org>
Co-developed-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Michał Górny <mgorny@gentoo.org>
---
--- a/Makefile	2023-10-18 16:13:06.496343048 -0400
+++ b/Makefile	2023-10-18 16:14:00.136587613 -0400
@@ -471,6 +471,7 @@ LZMA		= lzma
 LZ4		= lz4c
 XZ		= xz
 ZSTD		= zstd
+TAR    = tar
 
 PAHOLE_FLAGS	= $(shell PAHOLE=$(PAHOLE) $(srctree)/scripts/pahole-flags.sh)
 
@@ -519,7 +520,7 @@ CLANG_FLAGS :=
 export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE LD CC
 export CPP AR NM STRIP OBJCOPY OBJDUMP READELF PAHOLE RESOLVE_BTFIDS LEX YACC AWK INSTALLKERNEL
 export PERL PYTHON PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
-export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ ZSTD
+export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ ZSTD TAR
 export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE
 
 export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS
diff --git a/kernel/gen_kheaders.sh b/kernel/gen_kheaders.sh
index 1ef9a8751..82d539648 100755
--- a/kernel/gen_kheaders.sh
+++ b/kernel/gen_kheaders.sh
@@ -86,7 +86,7 @@ find $cpio_dir -type f -print0 |
 # 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}" \
+    ${TAR:-tar} "${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
 
-- 
2.40.0