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#!/bin/sh

# Copyright (C) 2005, 2006, 2007 Junjiro Okajima
#
# This program, aufs 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

# $Id: unionctl,v 1.16 2007/02/05 01:44:49 sfjro Exp $

# simple script for controling aufs.
# compatible with unionctl(8) in unionfs(5).
# if you use "mount -o remount" to add/del/mod branches,
# this scirpt is unnecessary.

PATH=/usr/bin:/usr/sbin:/bin:/sbin
export PATH
eecho() { echo "$@" 1>&2; }

me=`basename $0`
err=0
usage()
{
        eecho "${me}: $@"
        eecho usage:
        eecho "${me}" union_dir --add \
                '[ --before | --after bindex | branch ]' '[ --mode perm ]' branch
        eecho "${me}" union_dir --remove branch
        eecho "${me}" union_dir --mode branch perm
        eecho "${me}" union_dir --list
        eecho "${me}" union_dir '--whereis | --query1 | --q1' path_under_union '[ ,,, ]'
        err=1
}

conv() # [escape]
{
        sed -r -e '
        s/\\/\\134/g
        s/$/\\012/
        ' |
        tr -d '\n' |
        sed -r -e '
        s/ /\\040/g
        s/\t/\\011/g
        s/\r/\\015/g
        s/\\012$//
        ' |
        { test "$1" = "escape" && sed -r -e 's/\\/\\\\/g' || cat; }
        echo
}

tgt=
branches()
{
        echo "$tgt" |
        tr ',' '\n' |
        egrep '^(dirs|br)[=:]' |
        sed -r -e 's/^(dirs|br)[=:]//' |
        tr ':=' '\n '
}

########################################

test $# -lt 2 && eecho "${me}: bad arg $@" && exit 1
f=/proc/mounts
test ! -f $f && eecho "${me}: $f is necessary" && exit 1

set -e
#set -x; echo $@
tmp=/tmp/$$
cd "$1"
mntpnt="$PWD"
e_mntpnt=`echo "$mntpnt" | conv escape`
cd "$OLDPWD"
action="$2"
shift 2

tgt=`grep "aufs $e_mntpnt" $f | tail -1 | rev | cut -f3- -d' ' | rev`
test "$tgt" = "" && eecho "${me}: no such mntpnt $mntpnt" && exit 1
dev=`echo "$tgt" | sed -e 's: '"$mntpnt aufs"' .*$::`
branches > $tmp
#cat $tmp | while read i; do echo $i; done; exit

find_bindex() # dir
{
        echo "$1" | grep -q '^[0-9]*$' && echo "$1" && return 0
        local i n err
        n=0
        cat $tmp | rev | cut -f2- -d' ' | rev |
        while read i
        do
                test "$i" = "$1" && echo $n && return 0
                n=`expr $n + 1`
        done
        err=$?
        test $err -eq 0 && return 0
        rm -f $tmp
        eecho "${me}: no such branch $1"
        echo -2
        return 1
}

Remount() #options...
{
        rm -f $tmp
        local mount212p=0
        { mount --version 2> /dev/null || :; } | fgrep -q mount-2.12p && mount212p=1
        test $mount212p -eq 1 && exec mount -o remount,"$@" "$mntpnt"
        exec mount -o remount,"$@" "$dev" "$mntpnt"
}

do_add()
{
        local bindex perm br
        bindex=0
        perm=rw # unionfs default
        br=
        while [ "$br" = "" ]
        do
                case "$1" in
                --before)       bindex=`find_bindex "$2"`
                                bindex=`expr $bindex - 1` || :
                                ;;
                --after)        bindex=`find_bindex "$2"`
                                bindex=`expr $bindex + 1` || :
                                ;;
                --mode)         perm="$2";;
                --*)            eecho "${me}: unkown option $1"; return 1;;
                *)              br="$1"
                esac
                test "$br" = "" && shift 2 || :
        done

        test $# -ne 1 && eecho "${me}: bad arg $@" && return 1
        br="$1"
        test $bindex -lt 0 && bindex=0 || :
        Remount add:${bindex}:"${br}"="$perm"
}

do_del()
{
        test $# -ne 1 && eecho "${me}: bad arg $@" && return 1
        Remount del:"$1"
}

do_mod()
{
        test $# -ne 2 && eecho "${me}: bad arg $@" && return 1
        Remount mod:"$1"="$2"
}

do_list()
{
        local path mode
        cat $tmp | rev |
        while read mode path
        do
                mode=`echo $mode | rev`
                path=`echo "$path" | rev`
                case $mode in
                ro)     mode="r--";;
                rw)     mode="rw-";;
                ro+wh)  mode="R--";;
                *)      mode="---";;
                esac
                /bin/echo -e \\t"$path" \(${mode}\)
        done
}

do_query1()
{
        local path i f
        cat $tmp | rev | cut -f2- -d' ' | rev |
        while read path
        do
                for i
                do
                        i=`echo "$i" | sed -e 's:^/::'`
                        test -e "$mntpnt/$i" || continue
                        f="$path/$i"
                        test -e "$f" && if [ $# -eq 1 ]
                        then echo "$path"
                        else echo "$f"
                        fi || :
                done
        done
}

case "$action" in
--add)          do_add "$@";;
--remove)       do_del "$@";;
--mode)         do_mod "$@";;
--list)         do_list;;
--q1|--query1|--whereis)
                do_query1 "$@";;
--query)        usage "unsupported action $action"; err=1;;
*)              usage "unkown action $action"; err=1;;
esac

rm -f $tmp $tmp.*
exit $err