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=$1
10tmpdir=$outdir/${tarfile%/*}/.tmp_dir
11
12dir_list="
13include/
14arch/$SRCARCH/include/
15"
16
17# Support incremental builds by skipping archive generation
18# if timestamps of files being archived are not changed.
19
20# This block is useful for debugging the incremental builds.
21# Uncomment it for debugging.
22# if [ ! -f /tmp/iter ]; then iter=1; echo 1 > /tmp/iter;
23# else iter=$(($(cat /tmp/iter) + 1)); echo $iter > /tmp/iter; fi
24# find $all_dirs -name "*.h" | xargs ls -l > /tmp/ls-$iter
25
26all_dirs=
27if [ "$building_out_of_srctree" ]; then
28	for d in $dir_list; do
29		all_dirs="$all_dirs $srctree/$d"
30	done
31fi
32all_dirs="$all_dirs $dir_list"
33
34# include/generated/utsversion.h is ignored because it is generated after this
35# script is executed. (utsversion.h is unneeded for kheaders)
36#
37# When Kconfig regenerates include/generated/autoconf.h, its timestamp is
38# updated, but the contents might be still the same. When any CONFIG option is
39# changed, Kconfig touches the corresponding timestamp file include/config/*.
40# Hence, the md5sum detects the configuration change anyway. We do not need to
41# check include/generated/autoconf.h explicitly.
42#
43# Ignore them for md5 calculation to avoid pointless regeneration.
44headers_md5="$(find $all_dirs -name "*.h" -a			\
45		! -path include/generated/utsversion.h -a	\
46		! -path include/generated/autoconf.h		|
47		xargs ls -l | md5sum | cut -d ' ' -f1)"
48
49# Any changes to this script will also cause a rebuild of the archive.
50this_file_md5="$(ls -l $sfile | md5sum | cut -d ' ' -f1)"
51if [ -f $tarfile ]; then tarfile_md5="$(md5sum $tarfile | cut -d ' ' -f1)"; fi
52if [ -f kernel/kheaders.md5 ] &&
53	[ "$(head -n 1 kernel/kheaders.md5)" = "$headers_md5" ] &&
54	[ "$(head -n 2 kernel/kheaders.md5 | tail -n 1)" = "$this_file_md5" ] &&
55	[ "$(tail -n 1 kernel/kheaders.md5)" = "$tarfile_md5" ]; then
56		exit
57fi
58
59echo "  GEN     $tarfile"
60
61rm -rf "${tmpdir}"
62mkdir "${tmpdir}"
63
64if [ "$building_out_of_srctree" ]; then
65	(
66		cd $srctree
67		for f in $dir_list
68			do find "$f" -name "*.h";
69		done | tar -c -f - -T - | tar -xf - -C "${tmpdir}"
70	)
71fi
72
73for f in $dir_list;
74	do find "$f" -name "*.h";
75done | tar -c -f - -T - | tar -xf - -C "${tmpdir}"
76
77# Always exclude include/generated/utsversion.h
78# Otherwise, the contents of the tarball may vary depending on the build steps.
79rm -f "${tmpdir}/include/generated/utsversion.h"
80
81# Remove comments except SDPX lines
82# Use a temporary file to store directory contents to prevent find/xargs from
83# seeing temporary files created by perl.
84find "${tmpdir}" -type f -print0 > "${tmpdir}.contents.txt"
85xargs -0 -P8 -n1 \
86	perl -pi -e 'BEGIN {undef $/;}; s/\/\*((?!SPDX).)*?\*\///smg;' \
87	< "${tmpdir}.contents.txt"
88rm -f "${tmpdir}.contents.txt"
89
90# Create archive and try to normalize metadata for reproducibility.
91tar "${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 $tarfile -C "${tmpdir}/" . > /dev/null
95
96echo $headers_md5 > kernel/kheaders.md5
97echo "$this_file_md5" >> kernel/kheaders.md5
98echo "$(md5sum $tarfile | cut -d ' ' -f1)" >> kernel/kheaders.md5
99
100rm -rf "${tmpdir}"
101