# larch3 -  live 'hook' for mkinitcpio:
#                 deal with c2r,
#                 mount base system,
#                 load overlay,
#                 set up unioned root filesystem.
#                 Also manages overlay merging.

# Author: Michael Towers <gradgrind[at]online[dot]de>
#
# This file is part of the larch project.
#
#    larch 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.
#
#    larch 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 larch; if not, write to the Free Software Foundation, Inc.,
#    51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#
#----------------------------------------------------------------------------
# 2008.04.04

run_hook ()
{
    if [ "x${LDEV}" = "x" ]; then
        err "Sorry, couldn't find boot medium ..."
        break="y"
        return
    fi

    /sbin/modprobe loop

    # Path to compressed base system
    sysSqf=${cdmount}/system.sqf

    ovlpath=${cdmount}

    # A possibility to use alternative files:
    if [ -f ${cdmount}/larch/boot-init ]; then
        . ${cdmount}/larch/boot-init
    fi

    # Path to compressed 'modifications' archive
    modsSqf=${ovlpath}/mods.sqf
    # Default overlay file and directory
    overlay=${ovlpath}/overlay.ovl

    # Make union root
    /bin/mkdir /union

    # Deal with new archives
    if [ -f ${overlay}_ ]; then
        /bin/mount -o remount,rw ${LDEV} ${cdmount}
        /bin/mv ${overlay} ${overlay}~
        /bin/mv ${overlay}_ ${overlay}

        if [ -f ${modsSqf}_ ]; then
            /bin/mv ${modsSqf} ${modsSqf}~
            /bin/mv ${modsSqf}_ ${modsSqf}
        fi
        /bin/mount -o remount,ro ${LDEV} ${cdmount}
    fi

    # Boot option copy-to-ram (c2r)
    if [ "${c2r}" = "y" ]; then
        msg_ ":: Copying base system to RAM, this will take a while ..."
        /bin/cat ${sysSqf} > /tfs/system.sqf
        if [ $? -ne 0 ]; then
            err "Sorry, not enough RAM"
            break="y"
            return
        fi
        sysSqf=/tfs/system.sqf

        msg_ ":: Copying mods archive to RAM, this might take a while ..."
        /bin/cat ${modsSqf} > /tfs/mods.sqf
        if [ $? -ne 0 ]; then
            err "Sorry, not enough RAM"
            break="y"
            return
        fi
        modsSqf=/tfs/mods.sqf

        # force use of swap (if available)
        :> /tfs/swapon

    elif [ "${swap}" = "y" ]; then
        :> /tfs/swapon
    fi

    msg_ ":: Mounting squashed images"
    /bin/mkdir /tfs/system
    #added sleep for 3 seconds, because well i don't know but it seems to fix things
    sleep 3
    # The klibc mount command doesn't support '-o loop'
    /bin/losetup /dev/loop0 ${sysSqf}
    /bin/mount -r -t squashfs /dev/loop0 /tfs/system

    # Make stuff in 'system' available by providing the loader and
    # library path
    ldli=$( cd /tfs/system; echo lib/ld-linux*.so.2 )
    /bin/ln -s /tfs/system/${ldli} /${ldli}
    export LD_LIBRARY_PATH=/tfs/system/lib:/tfs/system/usr/lib

    /bin/mkdir /tfs/mods
    
    # The klibc mount command doesn't support '-o loop'
    /bin/losetup /dev/loop1 ${modsSqf}
    /bin/mount -r -t squashfs /dev/loop1 /tfs/mods

    # Unpack the overlay

    msg_ ":: Initializing writable layer for union (overlay)"
    /tfs/system/usr/bin/lzop -d < ${overlay} | \
            /tfs/system/bin/tar -C /tfs -xf -

    # Copy the installation tidy-up script (for removing custom live-only stuff),
    # and any other files in 'larch/copy' directory
    if [ -d ${ovlpath}/larch/copy ]; then
        cd ${ovlpath}/larch/copy
        for f in *; do
            cat ${f} >/tfs/${f}
        done
    fi

    msg_ ":: Setting up union file system"

    layers="/tfs/overlay=rw:/tfs/mods=${ovlmnt}:/tfs/system=${sqfmnt}"
    /bin/mount -t ${utype} -o ${bropt}${layers} ${utype} /union

    echo "${utype}" > /tfs/utype

    # Minimal device nodes needed before udev does its work
    /bin/mkdir /union/dev
    /bin/mknod /union/dev/console c 5 1
    /bin/mknod /union/dev/null c 1 3
    /bin/mknod /union/dev/zero c 1 5

    # Make special directories
    /bin/mkdir -m 1777 /union/tmp
    /bin/mkdir /union/media
    /bin/mkdir /union/sys
    /bin/mkdir /union/proc

    # Make the tmpfs stuff accessible within the union
    /bin/mkdir /union/.livesys
    /bin/mount -o bind /tfs /union/.livesys

    /bin/mkdir /union/.livesys/medium

    /bin/mount -o bind /tfs/system /union/.livesys/system
    /bin/mount -o bind /tfs/overlay /union/.livesys/overlay
    /bin/mount -o bind ${cdmount} /union/.livesys/medium

    if [ "x${modsSqf}" != "x" ]; then
        /bin/mount -o move /tfs/mods /union/.livesys/mods
    fi

    # Remember the boot device
    echo "${LDEV}" > /tfs/bootdevice

    if [ "${c2r}" = "y" ]; then
        # Set flag to inform system of copy-to-ram
        :> /tfs/c2r

        # Unmount boot device
        /bin/umount ${cdmount}
    fi

    msg_ ":: End of live system set-up"

    # Now some tweaks to alter 'init' actions from non-larch hooks, etc.
    # Override rootdelay from usb hook
    if [ "x${larchdelay}" = "x"  ]; then
        # To avoid spurious udevd pid numbers
        export rootdelay=1
    else
        # Allow adjustment via boot option
        export rootdelay=${larchdelay}
    fi
    # root must be set to something or other, even though larch doesn't
    # need it ...
    export root="/dev/loop0"
}

#######
# The actual root switch occurs later, when 'init' execs 'kinit'.
# I handle this by overwriting the 'kinit' binary with my own script.
# This will unmount dev, sys and proc and then exec run-init.
#######