#!/bin/sh

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

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

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