#!/bin/sh

  # SPDX-License-Identifier: GPL-2.0

  TARGET=$1
  ARCH=$2
  SMP=$3

  PREEMPT=$4

  PREEMPT_RT=$5

  CC_VERSION="$6"

  LD=$7

  # Do not expand names
  set -f

  # Fix the language to get consistent output
  LC_ALL=C
  export LC_ALL
  
  if [ -z "$KBUILD_BUILD_VERSION" ]; then

  	VERSION=$(cat .version 2>/dev/null || echo 1)

  else

  	VERSION=$KBUILD_BUILD_VERSION

  fi

  if [ -z "$KBUILD_BUILD_TIMESTAMP" ]; then
  	TIMESTAMP=`date`
  else
  	TIMESTAMP=$KBUILD_BUILD_TIMESTAMP
  fi

  if test -z "$KBUILD_BUILD_USER"; then

  	LINUX_COMPILE_BY=$(whoami | sed 's/\\/\\\\/')

  else
  	LINUX_COMPILE_BY=$KBUILD_BUILD_USER
  fi
  if test -z "$KBUILD_BUILD_HOST"; then

  	LINUX_COMPILE_HOST=`uname -n`

  else
  	LINUX_COMPILE_HOST=$KBUILD_BUILD_HOST
  fi

  
  UTS_VERSION="#$VERSION"

  CONFIG_FLAGS=""
  if [ -n "$SMP" ] ; then CONFIG_FLAGS="SMP"; fi
  if [ -n "$PREEMPT" ] ; then CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT"; fi

  if [ -n "$PREEMPT_RT" ] ; then CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT_RT"; fi

  
  # Truncate to maximum length

  UTS_LEN=64

  UTS_VERSION="$(echo $UTS_VERSION $CONFIG_FLAGS $TIMESTAMP | cut -b -$UTS_LEN)"

  
  # Generate a temporary compile.h

  { echo /\* This file is auto generated, version $VERSION \*/

    if [ -n "$CONFIG_FLAGS" ] ; then echo "/* $CONFIG_FLAGS */"; fi

    echo \#define UTS_MACHINE \"$ARCH\"

    echo \#define UTS_VERSION \"$UTS_VERSION\"

    printf '#define LINUX_COMPILE_BY "%s"
  ' "$LINUX_COMPILE_BY"

    echo \#define LINUX_COMPILE_HOST \"$LINUX_COMPILE_HOST\"

    LD_VERSION=$($LD -v | head -n1 | sed 's/(compatible with [^)]*)//' \
  		      | sed 's/[[:space:]]*$//')
    printf '#define LINUX_COMPILER "%s"
  ' "$CC_VERSION, $LD_VERSION"

  } > .tmpcompile

  
  # Only replace the real compile.h if the new one is different,
  # in order to preserve the timestamp and avoid unnecessary
  # recompilations.

  # We don't consider the file changed if only the date/time changed,
  # unless KBUILD_BUILD_TIMESTAMP was explicitly set (e.g. for
  # reproducible builds with that value referring to a commit timestamp).

  # A kernel config change will increase the generation number, thus

  # causing compile.h to be updated (including date/time) due to the

  # changed comment in the
  # first line.

  if [ -z "$KBUILD_BUILD_TIMESTAMP" ]; then
     IGNORE_PATTERN="UTS_VERSION"
  else
     IGNORE_PATTERN="NOT_A_PATTERN_TO_BE_MATCHED"
  fi

  if [ -r $TARGET ] && \

        grep -v $IGNORE_PATTERN $TARGET > .tmpver.1 && \
        grep -v $IGNORE_PATTERN .tmpcompile > .tmpver.2 && \

        cmp -s .tmpver.1 .tmpver.2; then
     rm -f .tmpcompile
  else

     echo "  UPD     $TARGET"

     mv -f .tmpcompile $TARGET
  fi
  rm -f .tmpver.1 .tmpver.2