#!/bin/bash
#
# mkdiscimage
#
# Create a disc image
#
# Usage mkdiscimage <image file> [<size>]
# size is in MB
#
# Version 1.0
#
# Copyright 2007 Simtec Electronics
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation
# files (the "Software"), to deal in the Software without
# restriction, including without limitation the rights to use, copy,
# modify, merge, publish, distribute, sublicense, and/or sell copies
# of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
#

DEFAULTSIZE=512
SWAPSIZE=128
DEBIAN_MIRROR="http://mirror/debian"
DEBIAN_SUITE=etch
DEBIAN_ARCH=arm
KERNEL_SRC=http://www.simtec.co.uk/products/SWLINUX/files
KERNEL_IMG=s3c24xx-linux-2.6.23-simtec1.tar.bz2


###################### end of parameters ######################

bootstrap_fs()
{
    MOUNT=$1
    ROOT_UUID=$2

    if [ "x${MOUNT}" = "x" ]; then
        return 1
    fi

    if [ "x${ROOT_UUID}" = "x" ]; then
        return 2
    fi

    OLDDIR=$(pwd)

    cd ${MOUNT}
    
    debootstrap --arch ${DEBIAN_ARCH} --foreign ${DEBIAN_SUITE} ${MOUNT} ${DEBIAN_MIRROR}

    wget ${KERNEL_SRC}/${KERNEL_IMG}
    tar -jxf ${KERNEL_IMG}
    rm ${KERNEL_IMG}

    echo "${DEBIAN_ARCH}" > ${MOUNT}/etc/hostname

    mknod ${MOUNT}/dev/console c 5 1
    mknod ${MOUNT}/dev/ttySAC0 c 204 64
    mknod ${MOUNT}/dev/ttySAC1 c 204 65
    mknod ${MOUNT}/dev/ttySAC2 c 204 66

    echo "# <file system> <mount point>   <type>  <options>       <dump>  <pass>" > ${MOUNT}/etc/fstab
    echo "proc /proc proc defaults 0 0" >> ${MOUNT}/etc/fstab

    echo "UUID=${ROOT_UUID} / ext3 defaults,errors=remount-ro 0" >> ${MOUNT}/etc/fstab

    cd ${OLDDIR}

}

bootstrap_e2fs ()
{
    DMDEVICE=$1

    if [ "x${DMDEVICE}" = "x" ]; then
        return 1
    fi

    # the devicemapper setup worked
    mke2fs -O dir_index,has_journal,sparse_super ${DMDEVICE}

    UUID=$(tune2fs -l ${DMDEVICE} | sed -n 's/^Filesystem UUID:[ \t]*\(.*\)/\1/p')

    mount ${DMDEVICE} /mnt

    if [ $? -eq 0 ];then
        bootstrap_fs /mnt $UUID
    fi

    umount ${DMDEVICE}
}

###################### main code ######################

FORM=virtdisc

# command line parameters
D=$(dirname $0)

# required tools
TOOLS="${D}/lspartab dd losetup parted dmsetup"

DISCIMAGE=$1
if [ "x${DISCIMAGE}" = "x" ]; then
    echo "usage:"
    echo "mkvirtdisc <image-filename> [<size>]"
    exit 1
fi

# ensure superuser privileges are available
if [ "x${UID}" = "x" -o "${UID}" -ne 0 ]; then
    which sudo >/dev/null
    if [ $? -ne 0 ]; then
        echo "Script requires superuser privileges!"
        exit 1
    else
        sudo $0 $*
        exit $?
    fi
fi

DISCSIZE=$2
if [ "x${DISCSIZE}" = "x" ]; then
    echo "Using default size of ${DEFAULTSIZE}"
    DISCSIZE=${DEFAULTSIZE}
fi


# ensure the required commands are present
which ${TOOLS} >/dev/null
if [ $? -ne 0 ]; then
    echo "Required command is missing"
    echo "${TOOLS}"
    exit 1
fi

# calculated values
ROOTSIZE=$(expr ${DISCSIZE} - ${SWAPSIZE})
READTAB="${D}/lspartab"

# check we can setup a loopback device
LOOP=$(losetup -f)

if [ "x${LOOP}" = "x" ]; then
    echo "Cannot find a loop"
    exit 1
fi

# create image file
dd if=/dev/zero of=${DISCIMAGE} bs=1M count=${DISCSIZE}

# partition it
parted --script ${DISCIMAGE} mklabel msdos mkpart primary ext2 0 ${ROOTSIZE} mkpartfs primary linux-swap ${ROOTSIZE} ${DISCSIZE}


# create device nodes
if ! losetup "${LOOP}" "${DISCIMAGE}"; then
    losetup -d "${LOOP}"
    echo "Unable to losetup!"
    exit 1
fi

LOOPNODE=$(stat -c '%t:%T' "${LOOP}")

"${READTAB}" "${DISCIMAGE}" | while read partnum start length type; do
    echo "Partition $FORM$partnum starts at $start and is $length sectors"
    echo "0 $length linear $LOOPNODE $start" | dmsetup create ${FORM}${partnum}
    if [ -b /dev/mapper/${FORM}${partnum} ]; then
        #device mapper setup was succesful

        case "${type}" in 
            ( "131" ) bootstrap_e2fs /dev/mapper/${FORM}${partnum} ;;
        esac
        

        dmsetup remove ${FORM}${partnum}
    fi
done


if ! losetup -d "${LOOP}"; then
    echo "losetup -d failed?"
    exit 1
fi

exit 0