xref: /openbmc/linux/kernel/gen_kheaders.sh (revision 93696d8f)
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    --owner=0 --group=0 --sort=name --numeric-owner --mode=u=rw,go=r,a+X \
93    -I $XZ -cf $tarfile -C $cpio_dir/ . > /dev/null
94
95echo $headers_md5 > kernel/kheaders.md5
96echo "$this_file_md5" >> kernel/kheaders.md5
97echo "$(md5sum $tarfile | cut -d ' ' -f1)" >> kernel/kheaders.md5
98
99rm -rf $cpio_dir
100