#!/bin/bash
#
#   pacman-uncage
#
#   Copyright (c) 2002-2006 by Andrew Rose <rose.andrew@gmail.com>
#   I used Judds pacman-optimise as a framework.
#
#   This program is free software; you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation; either version 2 of the License, or
#   (at your option) any later version.
#
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this program; if not, write to the Free Software
#   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
#   USA.
#

myver='2.9.8'
dbroot="/var/lib/pacman"
tmproot="/var/lib/pacman.new"
pacmandb="/var/lib/pacman.db"

usage() {
        echo "pacman-uncage $myver"
        echo "usage: $0 [pacman_db_root]"
        echo
        echo "pacman-uncage returns your pacman db to the generic style."
        echo
}

die() {
        echo "pacman-uncage: $*" >&2
        exit 1
}

die_r() {
        rm -f /tmp/pacman.lck
        die $*
}

if [ "$1" != "" ]; then
        if [ "$1" = "-h" -o "$1" = "--help" ]; then
                usage
                exit 0
        fi
        dbroot=$1
fi

if [ "`id -u`" != 0 ]; then
        die "You must be root to uncage the database"
fi

# make sure pacman isn't running
if [ -f /tmp/pacman.lck ]; then
        die "Pacman lockfile was found.  Cannot run while pacman is running."
fi

if [ ! -d $dbroot ]; then
        die "$dbroot does not exist or is not a directory"
fi

# don't let pacman run while we do this
touch /tmp/pacman.lck

# step 1: sum the old db
echo "==> md5sum'ing the old database..."
find $dbroot -type f | sort | xargs md5sum >/tmp/pacsums.old

echo "==> copying pacman.db contents back, note: the time needed to get a brew is now."
mkdir $tmproot
cp -a $dbroot/. $tmproot

echo "==> unmounting old dbroot and moving new one in"
umount $dbroot
rmdir $dbroot
mv $tmproot $dbroot

echo "==> md5sum'ing the new database..."
find $dbroot -type f | sort | xargs md5sum >/tmp/pacsums.new

echo "==> checking integrity..."
diff /tmp/pacsums.old /tmp/pacsums.new >/dev/null 2>&1
if [ $? -ne 0 ]; then
        # failed, move the old one back into place
        rm -rf $dbroot
        mkdir $dbroot
        mount -a
        die_r "integrity check FAILED, reverting to old database"
fi

echo "==> Removing old pacman.db"
rm $pacmandb

rm -f /tmp/pacman.lck /tmp/pacsums.old /tmp/pacsums.new
           
echo
echo "Finished.  Your pacman database has been uncaged!. Welcome home."
echo "You will need to remove the old mount line from your /etc/fstab"
echo

exit 0