linux-next/kernel/gen_kheaders.sh
David Howells 4f81dab9d6
kheaders: Ignore silly-rename files
Tell tar to ignore silly-rename files (".__afs*" and ".nfs*") when building
the header archive.  These occur when a file that is open is unlinked
locally, but hasn't yet been closed.  Such files are visible to the user
via the getdents() syscall and so programs may want to do things with them.

During the kernel build, such files may be made during the processing of
header files and the cleanup may get deferred by fput() which may result in
tar seeing these files when it reads the directory, but they may have
disappeared by the time it tries to open them, causing tar to fail with an
error.  Further, we don't want to include them in the tarball if they still
exist.

With CONFIG_HEADERS_INSTALL=y, something like the following may be seen:

   find: './kernel/.tmp_cpio_dir/include/dt-bindings/reset/.__afs2080': No such file or directory
   tar: ./include/linux/greybus/.__afs3C95: File removed before we read it

The find warning doesn't seem to cause a problem.

Fix this by telling tar when called from in gen_kheaders.sh to exclude such
files.  This only affects afs and nfs; cifs uses the Windows Hidden
attribute to prevent the file from being seen.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20241108173236.1382366-2-dhowells@redhat.com
cc: Masahiro Yamada <masahiroy@kernel.org>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: linux-nfs@vger.kernel.org
cc: linux-kernel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-12-02 11:21:17 +01:00

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#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
# This script generates an archive consisting of kernel headers
# for CONFIG_IKHEADERS.
set -e
sfile="$(readlink -f "$0")"
outdir="$(pwd)"
tarfile=$1
cpio_dir=$outdir/${tarfile%/*}/.tmp_cpio_dir
dir_list="
include/
arch/$SRCARCH/include/
"
if ! command -v cpio >/dev/null; then
echo >&2 "***"
echo >&2 "*** 'cpio' could not be found."
echo >&2 "***"
exit 1
fi
# Support incremental builds by skipping archive generation
# if timestamps of files being archived are not changed.
# This block is useful for debugging the incremental builds.
# Uncomment it for debugging.
# if [ ! -f /tmp/iter ]; then iter=1; echo 1 > /tmp/iter;
# else iter=$(($(cat /tmp/iter) + 1)); echo $iter > /tmp/iter; fi
# find $all_dirs -name "*.h" | xargs ls -l > /tmp/ls-$iter
all_dirs=
if [ "$building_out_of_srctree" ]; then
for d in $dir_list; do
all_dirs="$all_dirs $srctree/$d"
done
fi
all_dirs="$all_dirs $dir_list"
# include/generated/utsversion.h is ignored because it is generated after this
# script is executed. (utsversion.h is unneeded for kheaders)
#
# When Kconfig regenerates include/generated/autoconf.h, its timestamp is
# updated, but the contents might be still the same. When any CONFIG option is
# changed, Kconfig touches the corresponding timestamp file include/config/*.
# Hence, the md5sum detects the configuration change anyway. We do not need to
# check include/generated/autoconf.h explicitly.
#
# Ignore them for md5 calculation to avoid pointless regeneration.
headers_md5="$(find $all_dirs -name "*.h" |
grep -v "include/generated/utsversion.h" |
grep -v "include/generated/autoconf.h" |
xargs ls -l | md5sum | cut -d ' ' -f1)"
# Any changes to this script will also cause a rebuild of the archive.
this_file_md5="$(ls -l $sfile | md5sum | cut -d ' ' -f1)"
if [ -f $tarfile ]; then tarfile_md5="$(md5sum $tarfile | cut -d ' ' -f1)"; fi
if [ -f kernel/kheaders.md5 ] &&
[ "$(head -n 1 kernel/kheaders.md5)" = "$headers_md5" ] &&
[ "$(head -n 2 kernel/kheaders.md5 | tail -n 1)" = "$this_file_md5" ] &&
[ "$(tail -n 1 kernel/kheaders.md5)" = "$tarfile_md5" ]; then
exit
fi
echo " GEN $tarfile"
rm -rf $cpio_dir
mkdir $cpio_dir
if [ "$building_out_of_srctree" ]; then
(
cd $srctree
for f in $dir_list
do find "$f" -name "*.h";
done | cpio --quiet -pd $cpio_dir
)
fi
# The second CPIO can complain if files already exist which can happen with out
# of tree builds having stale headers in srctree. Just silence CPIO for now.
for f in $dir_list;
do find "$f" -name "*.h";
done | cpio --quiet -pdu $cpio_dir >/dev/null 2>&1
# Remove comments except SDPX lines
find $cpio_dir -type f -print0 |
xargs -0 -P8 -n1 perl -pi -e 'BEGIN {undef $/;}; s/\/\*((?!SPDX).)*?\*\///smg;'
# Create archive and try to normalize metadata for reproducibility.
tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \
--exclude=".__afs*" --exclude=".nfs*" \
--owner=0 --group=0 --sort=name --numeric-owner --mode=u=rw,go=r,a+X \
-I $XZ -cf $tarfile -C $cpio_dir/ . > /dev/null
echo $headers_md5 > kernel/kheaders.md5
echo "$this_file_md5" >> kernel/kheaders.md5
echo "$(md5sum $tarfile | cut -d ' ' -f1)" >> kernel/kheaders.md5
rm -rf $cpio_dir