1#!/bin/sh
2# SPDX-License-Identifier: GPL-2.0
3
4TARGET=$1
5ARCH=$2
6SMP=$3
7PREEMPT=$4
8PREEMPT_RT=$5
9CC_VERSION="$6"
10LD=$7
11
12# Do not expand names
13set -f
14
15# Fix the language to get consistent output
16LC_ALL=C
17export LC_ALL
18
19if [ -z "$KBUILD_BUILD_VERSION" ]; then
20	VERSION=$(cat .version 2>/dev/null || echo 1)
21else
22	VERSION=$KBUILD_BUILD_VERSION
23fi
24
25if [ -z "$KBUILD_BUILD_TIMESTAMP" ]; then
26	TIMESTAMP=`date`
27else
28	TIMESTAMP=$KBUILD_BUILD_TIMESTAMP
29fi
30if test -z "$KBUILD_BUILD_USER"; then
31	LINUX_COMPILE_BY=$(whoami | sed 's/\\/\\\\/')
32else
33	LINUX_COMPILE_BY=$KBUILD_BUILD_USER
34fi
35if test -z "$KBUILD_BUILD_HOST"; then
36	LINUX_COMPILE_HOST=`uname -n`
37else
38	LINUX_COMPILE_HOST=$KBUILD_BUILD_HOST
39fi
40
41UTS_VERSION="#$VERSION"
42CONFIG_FLAGS=""
43if [ -n "$SMP" ] ; then CONFIG_FLAGS="SMP"; fi
44if [ -n "$PREEMPT" ] ; then CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT"; fi
45if [ -n "$PREEMPT_RT" ] ; then CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT_RT"; fi
46
47# Truncate to maximum length
48UTS_LEN=64
49UTS_VERSION="$(echo $UTS_VERSION $CONFIG_FLAGS $TIMESTAMP | cut -b -$UTS_LEN)"
50
51# Generate a temporary compile.h
52
53{ echo /\* This file is auto generated, version $VERSION \*/
54  if [ -n "$CONFIG_FLAGS" ] ; then echo "/* $CONFIG_FLAGS */"; fi
55
56  echo \#define UTS_MACHINE \"$ARCH\"
57
58  echo \#define UTS_VERSION \"$UTS_VERSION\"
59
60  printf '#define LINUX_COMPILE_BY "%s"\n' "$LINUX_COMPILE_BY"
61  echo \#define LINUX_COMPILE_HOST \"$LINUX_COMPILE_HOST\"
62
63  LD_VERSION=$($LD -v | head -n1 | sed 's/(compatible with [^)]*)//' \
64		      | sed 's/[[:space:]]*$//')
65  printf '#define LINUX_COMPILER "%s"\n' "$CC_VERSION, $LD_VERSION"
66} > .tmpcompile
67
68# Only replace the real compile.h if the new one is different,
69# in order to preserve the timestamp and avoid unnecessary
70# recompilations.
71# We don't consider the file changed if only the date/time changed,
72# unless KBUILD_BUILD_TIMESTAMP was explicitly set (e.g. for
73# reproducible builds with that value referring to a commit timestamp).
74# A kernel config change will increase the generation number, thus
75# causing compile.h to be updated (including date/time) due to the
76# changed comment in the
77# first line.
78
79if [ -z "$KBUILD_BUILD_TIMESTAMP" ]; then
80   IGNORE_PATTERN="UTS_VERSION"
81else
82   IGNORE_PATTERN="NOT_A_PATTERN_TO_BE_MATCHED"
83fi
84
85if [ -r $TARGET ] && \
86      grep -v $IGNORE_PATTERN $TARGET > .tmpver.1 && \
87      grep -v $IGNORE_PATTERN .tmpcompile > .tmpver.2 && \
88      cmp -s .tmpver.1 .tmpver.2; then
89   rm -f .tmpcompile
90else
91   echo "  UPD     $TARGET"
92   mv -f .tmpcompile $TARGET
93fi
94rm -f .tmpver.1 .tmpver.2
95