#!/bin/sh
#
# mapsector -- Map sector number to file name(s)
#
# Copyright (C) 2009,2010 Stefan Bund <stefan@j32.de>
#
# 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.
#

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

mappers=""
scanners=""
version="unknown"
name="`basename "$0"`"

# Don't use custom language since we parse the output of lots of standard
# utilities
unset LANG

register_mapper()
{
    mappers="${mappers}${mappers:+ }$1"
}

register_scanner()
{
    scanners="${scanners}${scanners:+ }$1"
}

load()
{
    local X
    local lib

    X="`dirname "$0"`"
    if [ "`basename "$X"`" == "bin" ]; then # `"
        libdir="`dirname "$X"`/share/$name" #`"
    fi
    if [ -z "$libdir" -o ! -d "$libdir" ]; then
        libdir="$X/lib"
    fi

    if [ ! -d "$libdir" ]; then
        echo "! Library directory not found" 1>&2
        exit 1
    fi

    for lib in `ls "$libdir"/[0-9][0-9]_*.sh | sort`; do
        source $lib
    done
}

# Map device/sector through blockdevice mappings (e.g. lvm)

map()
{
    local found
    found=1
    while [ -n "$found" ]; do
        found=""
        for name in $mappers; do
            if detect_$name; then
                found=1
                if do_$name; then
                    return
                fi
                break
            fi
        done
    done
}

scan()
{
    for name in $scanners; do
        if detect_$name; then
            if do_$name; then
                return
            fi
        fi
    done
}

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

#### Load library modules

load

#### Parse command line arguments

X=`getopt -o "hV" --long "help,noscan,version" -n "$name" -- "$@"`
if [ $? != 0 ]; then exit 1; fi
eval set -- "$X"

noscan=""
help=""

while true; do
    case "$1" in
        -h|--help) help="0"; shift ;;
        --noscan) noscan="0"; shift ;;
        -V|--version) echo "$name $version"; exit 0 ;;
        --) shift; break ;;
        *) echo "! internal error"; exit 1 ;;
    esac
done

if [ -n "$help" -o -z "$2" ]; then
    cat <<EOF
Usage: $name [-h|--help] [--noscan] <device> <sector>"

mapsector -- Map sector number to file name(s)

Given a device and a sector number, mapsector will try to find the
file name(s) mapping to this sector. It will try to gather as much
information about the given sector as possible.

mapsector currently has support for the following mapping schemes:

EOF
    for mapper in $mappers; do
        describe_$mapper
    done
    cat <<EOF

mapsector currently supports the following filesystems

EOF
    for scanner in $scanners; do
        describe_$scanner
    done
cat <<EOF

mapsector will try it's best to find an associated file name but
depending on the filesystem state and the type of sector (e.g. if
the sector is part of a filesystem metadata block) this may not be
possible.

For mapsector to work, the filesystem must be currently active
(e.g. LVM must be running, crypted devices must have been set up). The
filesystem must not necessarily be mounted (though if mounted,
mapsector will give you the mountpoint).

if '--noscan' is given, the possibly lengthy (!!) filesystem scan for
filenames is skipped.

-- mapsector $version
EOF
    exit "${help:-1}"
fi

device="$1"
sector="$2"

echo "device $device"
echo "sector $sector"

map
if [ -z "$noscan" ]; then
    scan
fi