#!/bin/bash

function usage ()
{
	echo $0 'Check for kernel defconfig mismacth'
	echo 'Usage:'
	echo '	'$0' [-c] [-u] [defconfig-files]'
	echo '	    -c	Check changed defconfigs from last git commit'
	echo '	    -u	Update defconfig if no mismatch is found'
	echo '	    -h	This help'
	exit 0
}

CONFIGS=
OUT=out-$$
FAIL=0
UPDATE=0
CHECK_COMMIT=0

while getopts "cuh" opt; do
    case $opt in
      c)
	if [ $# == 2 ]; then
		CHECK_COMMIT=$2
	else
		CHECK_COMMIT="HEAD"
	fi
	CONFIGS=`git show ${CHECK_COMMIT} --stat | gawk '/arch\/(arm64|arm)\/configs\/.*_defconfig +\| +[0-9]*/{print $1}'`

	if [ ".$CONFIGS" != "." ]; then
		echo From git commit: Checking $CONFIGS
	fi
	;;
      u)
	UPDATE=1
	;;
      h)
      	usage
      	;;
    esac
done

if [ $# == 0 ]; then
	usage
fi

if [ $CHECK_COMMIT == 0 ]; then
	shift $((OPTIND-1))
	CONFIGS="${CONFIGS} $*"
fi

mkdir ${OUT}

for CONFIG in $CONFIGS ; do
	if [ ! -e ${CONFIG} ]; then
		echo warning: defconfig file $CONFIG not found
		continue
	fi

	echo $CONFIG | grep arch/arm64 > /dev/null
	RETVAL=$?
	if [ $RETVAL != 0 ]; then
		ARCH=arm
	else
		ARCH=arm64
	fi

	make ARCH=${ARCH} O=${OUT} `basename ${CONFIG}` savedefconfig
	RETVAL=$?
	if [ $RETVAL != 0 ]; then
		echo error: Make ${CONFIG} error
		FAIL=1
		continue
	fi

	# Check option mismatch
	echo ${CONFIG} ${OUT}/.config
	gawk 'BEGIN{lastf="";} { if (lastf != FILENAME) { if (lastf != "") CHECK=1; lastf=FILENAME; } }  \
		/CONFIG_/ { match($0, /CONFIG_[^ =]*/); option=substr($0, RSTART, RLENGTH); \
			if (CHECK==1) {  if (option in opts && opts[option]==$0) delete opts[option]; } \
				else { if (option in opts && opts[option]!=$0) dups[option]=$0; opts[option]=$0; } }  \
		END { C=0; RET=0; for (i in dups) { RET=1; C++; printf("error: %s duplicate in defconfig\n", i); } \
			for (i in opts) { RET=1; C++;  printf("error: %s mismatch\n", i); } exit(RET);}' ${CONFIG} ${OUT}/.config
	RETVAL=$?
	if [ $RETVAL != 0 ]; then
		echo error: ${CONFIG}: defconfig mismatch. Please check Kconfig and follow SOP to update _defconfig.
		FAIL=1
		continue
	fi

	if [ $UPDATE == 0 ]; then
		# Compare output, make sure format is correct
		cmp ${OUT}/defconfig ${CONFIG} > /dev/null
		RETVAL=$?
		if [ $RETVAL != 0 ]; then
			echo error: ${CONFIG} compare error. Please follow SOP to update _defconfig
			FAIL=1
			continue
		fi
	else
		cp ${OUT}/defconfig ${CONFIG}
	fi
done

if [ $FAIL == 1 ]; then
	echo
	echo Please be informed that we had phased in defconfig check mechanism in kernel preflight for kernel 3.18 on 2015/7/27.
	echo
	echo Please check the following wiki for detail, thanks!
	echo http://wiki.mediatek.inc/display/KernelStandardization/Check+defconfig+in+kernel+preflight
	echo http://wiki.mediatek.inc/display/KernelStandardization/SOP+to+update+kernel+config
fi

rm -rf ${OUT}
exit $FAIL