#!/bin/sh
#
#   All rights reserved, copyright (c) 2011, Mitzyuki IMAIZUMI
#   $Id: cipher,v 1.1 2011/02/09 10:32:09 mitz Exp $
#

myname=${0##*/}
tmpfile=${TMP:-/tmp}/${myname}.$$
enc="openssl enc -e -aes-128-cbc -in "
dec="openssl enc -d -aes-128-cbc -in "

trap 'rm -r ${tmpfile}; exit' 0 1 2 3 9 15

if opt=`getopt dep: $*`
then
	set -- ${opt}
	while [ -n "${1}" ] 
	do
		case "${1}" in
			-d )
				force=${dec};;
			-e )
				force=${enc};;
			-p )
				pass="-pass pass:${2}"
				shift;;
			-- )
				shift
				break;;
		esac
		shift
	done
else
	echo "Usage: ${myname} [-d][-e][-p pass] file[, ... file]" 1>&2
	exit 255
fi

for i
do
	if [ -f ${i} ]
	then
		if [ -z "${force}" ]
		then
			# magic number を取得してファイル種別を自動判別
			if [ "`dd if=${i} bs=8 count=1 2> /dev/null`" = "Salted__" ]
			then
				command=${dec}
			else
				command=${enc}
			fi
		else
			command=${force}
		fi
		# 暗号化/復号化が成功した場合は元ファイルを置換
		${command} ${i} -out ${tmpfile} ${pass} && mv ${tmpfile} ${i}
	else
		echo "${myname}: cannot open ${i} for input" 1>&2
	fi
done