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/$tarfile.tmp
11
12dir_list="
13include/
14arch/$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 $dir_list"
33
34# include/generated/compile.h is ignored because it is touched even when none
35# of the source files changed.
36#
37# When Kconfig regenerates include/generated/autoconf.h, its timestamp is
38# updated, but the contents might be still the same. When any CONFIG option is
39# changed, Kconfig touches the corresponding timestamp file include/config/*.
40# Hence, the md5sum detects the configuration change anyway. We do not need to
41# check include/generated/autoconf.h explicitly.
42#
43# Ignore them for md5 calculation to avoid pointless regeneration.
44headers_md5="$(find $all_dirs -name "*.h"			|
45		grep -v "include/generated/compile.h"	|
46		grep -v "include/generated/autoconf.h"	|
47		xargs ls -l | md5sum | cut -d ' ' -f1)"
48
49# Any changes to this script will also cause a rebuild of the archive.
50this_file_md5="$(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 $cpio_dir
62mkdir $cpio_dir
63
64if [ "$building_out_of_srctree" ]; then
65	(
66		cd $srctree
67		for f in $dir_list
68			do find "$f" -name "*.h";
69		done | cpio --quiet -pd $cpio_dir
70	)
71fi
72
73# The second CPIO can complain if files already exist which can happen with out
74# of tree builds having stale headers in srctree. Just silence CPIO for now.
75for f in $dir_list;
76	do find "$f" -name "*.h";
77done | cpio --quiet -pd $cpio_dir >/dev/null 2>&1
78
79# Remove comments except SDPX lines
80find $cpio_dir -type f -print0 |
81	xargs -0 -P8 -n1 perl -pi -e 'BEGIN {undef $/;}; s/\/\*((?!SPDX).)*?\*\///smg;'
82
83# Create archive and try to normalize metadata for reproducibility.
84# For compatibility with older versions of tar, files are fed to tar
85# pre-sorted, as --sort=name might not be available.
86find $cpio_dir -printf "./%P\n" | LC_ALL=C sort | \
87    tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \
88    --owner=0 --group=0 --numeric-owner --no-recursion \
89    -I $XZ -cf $tarfile -C $cpio_dir/ -T - > /dev/null
90
91echo $headers_md5 > kernel/kheaders.md5
92echo "$this_file_md5" >> kernel/kheaders.md5
93echo "$(md5sum $tarfile | cut -d ' ' -f1)" >> kernel/kheaders.md5
94
95rm -rf $cpio_dir
96