#!/bin/bash
# Translate the bits making up a GFP mask
# (c) 2009, Mel Gorman <mel@csn.ul.ie>
# Licensed under the terms of the GNU GPL License version 2
SOURCE=
GFPMASK=none

# Helper function to report failures and exit
die() {
	echo ERROR: $@
	if [ "$TMPFILE" != "" ]; then
		rm -f $TMPFILE
	fi
	exit -1
}

usage() {
	echo "usage: gfp-translate [-h] [ --source DIRECTORY ] gfpmask"
	exit 0
}

# Parse command-line arguements
while [ $# -gt 0 ]; do
	case $1 in
		--source)
			SOURCE=$2
			shift 2
			;;
		-h)
			usage
			;;
		--help)
			usage
			;;
		*)
			GFPMASK=$1
			shift
			;;
	esac
done

# Guess the kernel source directory if it's not set. Preference is in order of
# o current directory
# o /usr/src/linux
if [ "$SOURCE" = "" ]; then
	if [ -r "/usr/src/linux/Makefile" ]; then
		SOURCE=/usr/src/linux
	fi
	if [ -r "`pwd`/Makefile" ]; then
		SOURCE=`pwd`
	fi
fi

# Confirm that a source directory exists
if [ ! -r "$SOURCE/Makefile" ]; then
	die "Could not locate kernel source directory or it is invalid"
fi

# Confirm that a GFP mask has been specified
if [ "$GFPMASK" = "none" ]; then
	usage
fi

# Extract GFP flags from the kernel source
TMPFILE=`mktemp -t gfptranslate-XXXXXX` || exit 1
grep "^#define __GFP" $SOURCE/include/linux/gfp.h | sed -e 's/(__force gfp_t)//' | sed -e 's/u)/)/' | grep -v GFP_BITS | sed -e 's/)\//) \//' > $TMPFILE

# Parse the flags
IFS="
"
echo Source: $SOURCE
echo Parsing: $GFPMASK
for LINE in `cat $TMPFILE`; do
	MASK=`echo $LINE | awk '{print $3}'`
	if [ $(($GFPMASK&$MASK)) -ne 0 ]; then
		echo $LINE
	fi
done

rm -f $TMPFILE
exit 0