#!/bin/sh

set -e

_adopt_conffile() {
    conffile=$1
    pkg=$2

    [ -f ${conffile}.dpkg-bak ] || return 0

    md5sum="$(md5sum ${conffile} | sed -e 's/ .*//')"
    old_md5sum="$(dpkg-query -W -f='${Conffiles}' $pkg | \
                        sed -n -e "\' ${conffile} ' { s/ obsolete$//; s/.* //; p }")"
    # On new installs, if the conffile was preserved on upgrade by
    # dpkg-maintscript helper, copy it back if the new file has not been
    # modified yet
    if [ "$md5sum" = "$old_md5sum" ]; then
        mv ${conffile}.dpkg-bak ${conffile}
    fi
}

if [ "$1" = configure ] && [ -z "$2" ]; then
    _adopt_conffile /etc/login.defs login.defs
fi