#!/bin/sh

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

  PREEMPT=$4
  CC=$5

  vecho() { [ "${quiet}" = "silent_" ] || echo "$@" ; }

  # If compile.h exists already and we don't own autoconf.h
  # (i.e. we're not the same user who did make *config), don't
  # modify compile.h
  # So "sudo make install" won't change the "compiled by <user>"
  # do "compiled by root"

  if [ -r $TARGET -a ! -O include/generated/autoconf.h ]; then

    vecho "  SKIPPED $TARGET"

    exit 0
  fi
  
  # 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
  	if [ -r .version ]; then
  		VERSION=`cat .version`
  	else
  		VERSION=0
  		echo 0 > .version
  	fi

  else

  	VERSION=$KBUILD_BUILD_VERSION

  fi

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

  
  UTS_VERSION="#$VERSION"

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

  UTS_VERSION="$UTS_VERSION $CONFIG_FLAGS $TIMESTAMP"

  
  # Truncate to maximum length
  
  UTS_LEN=64

  UTS_TRUNCATE="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 \"`echo $UTS_VERSION | $UTS_TRUNCATE`\"

    echo \#define LINUX_COMPILE_TIME \"`date +%T`\"

    echo \#define LINUX_COMPILE_BY \"`whoami`\"
    echo \#define LINUX_COMPILE_HOST \"`hostname | $UTS_TRUNCATE`\"
  
    if [ -x /bin/dnsdomainname ]; then

      domain=`dnsdomainname 2> /dev/null`

    elif [ -x /bin/domainname ]; then

      domain=`domainname 2> /dev/null`
    fi
  
    if [ -n "$domain" ]; then
      echo \#define LINUX_COMPILE_DOMAIN \"`echo $domain | $UTS_TRUNCATE`\"

    else
      echo \#define LINUX_COMPILE_DOMAIN
    fi

    echo \#define LINUX_COMPILER \"`$CC -v 2>&1 | tail -n 1`\"

  ) > .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.
  # 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 [ -r $TARGET ] && \
        grep -v 'UTS_VERSION\|LINUX_COMPILE_TIME' $TARGET > .tmpver.1 && \
        grep -v 'UTS_VERSION\|LINUX_COMPILE_TIME' .tmpcompile > .tmpver.2 && \
        cmp -s .tmpver.1 .tmpver.2; then
     rm -f .tmpcompile
  else

     vecho "  UPD     $TARGET"

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