#!/bin/sh

#

# This script uses debugfs command to populate the ext2/3/4 filesystem

# from a given directory.

#

do_usage () {

	cat << _EOF

Usage: populate-extfs.sh <source> <device>

Create an ext2/ext3/ext4 filesystem from a directory or file

  source: The source directory or file

  device: The target device

_EOF

	exit 1

}

[ $# -ne 2 ] && do_usage

SRCDIR=${1%%/}

DEVICE=$2

# Find where is the debugfs command if not found in the env.

if [ -z "$DEBUGFS" ]; then

	CONTRIB_DIR=$(dirname $(readlink -f $0))

	DEBUGFS="$CONTRIB_DIR/../debugfs/debugfs"

fi

{

	CWD="/"

	find $SRCDIR | while read FILE; do

                TGT="${FILE##*/}"

                DIR="${FILE#$SRCDIR}"

                DIR="${DIR%$TGT}"

		# Skip the root dir

		[ ! -z "$DIR" ] || continue

		[ ! -z "$TGT" ] || continue

		if [ "$DIR" != "$CWD" ]; then

			echo "cd $DIR"

			CWD="$DIR"

		fi

		# Only stat once since stat is a time consuming command

		STAT=$(stat -c "TYPE=\"%F\";DEVNO=\"0x%t 0x%T\";MODE=\"%f\";U=\"%u\";G=\"%g\"" $FILE)

		eval $STAT

		case $TYPE in

		"directory")

			echo "mkdir $TGT"

			;;

		"regular file" | "regular empty file")

			echo "write $FILE $TGT"

			;;

		"symbolic link")

			LINK_TGT=$(readlink $FILE)

			echo "symlink $TGT $LINK_TGT"

			;;

		"block special file")

			echo "mknod $TGT b $DEVNO"

			;;

		"character special file")

			echo "mknod $TGT c $DEVNO"

			;;

		"fifo")

			echo "mknod $TGT p"

			;;

		*)

			echo "Unknown/unhandled file type '$TYPE' file: $FILE" 1>&2

			;;

		esac

		# Set the file mode

		echo "sif $TGT mode 0x$MODE"

		# Set uid and gid

		echo "sif $TGT uid $U"

		echo "sif $TGT gid $G"

	done

	# Handle the hard links.

	# Save the hard links to a file, use the inode number as the filename, for example:

	# If a and b's inode number is 6775928, save a and b to /tmp/tmp.VrCwHh5gdt/6775928.

	INODE_DIR=`mktemp -d` || exit 1

	for i in `find $SRCDIR -type f -links +1 -printf 'INODE=%i###FN=%p\n'`; do

		eval `echo $i | sed 's$###$ $'`

		echo ${FN#$SRCDIR} >>$INODE_DIR/$INODE

	done

	# Use the debugfs' ln and "sif links_count" to handle them.

	for i in `ls $INODE_DIR`; do

		# The link source

		SRC=`head -1 $INODE_DIR/$i`

		# Remove the files and link them again except the first one

		for TGT in `sed -n -e '1!p' $INODE_DIR/$i`; do

			echo "rm $TGT"

			echo "ln $SRC $TGT"

		done

		LN_CNT=`cat $INODE_DIR/$i | wc -l`

		# Set the links count

		echo "sif $SRC links_count $LN_CNT"

	done

	rm -fr $INODE_DIR

} | $DEBUGFS -w -f - $DEVICE