1#!/bin/sh
  2# SPDX-License-Identifier: GPL-2.0
  3
  4# This script generates an archive consisting of kernel headers
  5# for CONFIG_IKHEADERS.
  6set -e
  7sfile="$(readlink -f "$0")"
  8outdir="$(pwd)"
  9tarfile=$1
 10cpio_dir=$outdir/${tarfile%/*}/.tmp_cpio_dir
 11
 12dir_list="
 13include/
 14arch/$SRCARCH/include/
 15"
 16
 17if ! command -v cpio >/dev/null; then
 18	echo >&2 "***"
 19	echo >&2 "*** 'cpio' could not be found."
 20	echo >&2 "***"
 21	exit 1
 22fi
 23
 24# Support incremental builds by skipping archive generation
 25# if timestamps of files being archived are not changed.
 26
 27# This block is useful for debugging the incremental builds.
 28# Uncomment it for debugging.
 29# if [ ! -f /tmp/iter ]; then iter=1; echo 1 > /tmp/iter;
 30# else iter=$(($(cat /tmp/iter) + 1)); echo $iter > /tmp/iter; fi
 31# find $all_dirs -name "*.h" | xargs ls -l > /tmp/ls-$iter
 32
 33all_dirs=
 34if [ "$building_out_of_srctree" ]; then
 35	for d in $dir_list; do
 36		all_dirs="$all_dirs $srctree/$d"
 37	done
 38fi
 39all_dirs="$all_dirs $dir_list"
 40
 41# include/generated/utsversion.h is ignored because it is generated after this
 42# script is executed. (utsversion.h is unneeded for kheaders)
 43#
 44# When Kconfig regenerates include/generated/autoconf.h, its timestamp is
 45# updated, but the contents might be still the same. When any CONFIG option is
 46# changed, Kconfig touches the corresponding timestamp file include/config/*.
 47# Hence, the md5sum detects the configuration change anyway. We do not need to
 48# check include/generated/autoconf.h explicitly.
 49#
 50# Ignore them for md5 calculation to avoid pointless regeneration.
 51headers_md5="$(find $all_dirs -name "*.h"			|
 52		grep -v "include/generated/utsversion.h"	|
 53		grep -v "include/generated/autoconf.h"	|
 54		xargs ls -l | md5sum | cut -d ' ' -f1)"
 55
 56# Any changes to this script will also cause a rebuild of the archive.
 57this_file_md5="$(ls -l $sfile | md5sum | cut -d ' ' -f1)"
 58if [ -f $tarfile ]; then tarfile_md5="$(md5sum $tarfile | cut -d ' ' -f1)"; fi
 59if [ -f kernel/kheaders.md5 ] &&
 60	[ "$(head -n 1 kernel/kheaders.md5)" = "$headers_md5" ] &&
 61	[ "$(head -n 2 kernel/kheaders.md5 | tail -n 1)" = "$this_file_md5" ] &&
 62	[ "$(tail -n 1 kernel/kheaders.md5)" = "$tarfile_md5" ]; then
 63		exit
 64fi
 65
 66echo "  GEN     $tarfile"
 67
 68rm -rf $cpio_dir
 69mkdir $cpio_dir
 70
 71if [ "$building_out_of_srctree" ]; then
 72	(
 73		cd $srctree
 74		for f in $dir_list
 75			do find "$f" -name "*.h";
 76		done | cpio --quiet -pd $cpio_dir
 77	)
 78fi
 79
 80# The second CPIO can complain if files already exist which can happen with out
 81# of tree builds having stale headers in srctree. Just silence CPIO for now.
 82for f in $dir_list;
 83	do find "$f" -name "*.h";
 84done | cpio --quiet -pdu $cpio_dir >/dev/null 2>&1
 85
 86# Remove comments except SDPX lines
 87find $cpio_dir -type f -print0 |
 88	xargs -0 -P8 -n1 perl -pi -e 'BEGIN {undef $/;}; s/\/\*((?!SPDX).)*?\*\///smg;'
 89
 90# Create archive and try to normalize metadata for reproducibility.
 91tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \
 92    --exclude=".__afs*" --exclude=".nfs*" \
 93    --owner=0 --group=0 --sort=name --numeric-owner --mode=u=rw,go=r,a+X \
 94    -I $XZ -cf $tarfile -C $cpio_dir/ . > /dev/null
 95
 96echo $headers_md5 > kernel/kheaders.md5
 97echo "$this_file_md5" >> kernel/kheaders.md5
 98echo "$(md5sum $tarfile | cut -d ' ' -f1)" >> kernel/kheaders.md5
 99
100rm -rf $cpio_dir