#!/bin/sh

# set -e

export PATH=/usr/bin:/usr/sbin:/bin:/sbin

mountpoint=/cdrom
LIVE_MEDIA_PATH=casper
LIVE_ROOTFS=filesystem.squashfs

USERNAME=casper
USERFULLNAME="Live session user"
HOST=live
BUILD_SYSTEM=Custom

mkdir -p $mountpoint
tried=/tmp/tried

[ -f /etc/casper.conf ] && . /etc/casper.conf
export USERNAME USERFULLNAME HOST BUILD_SYSTEM

. /scripts/functions
. /scripts/casper-helpers

if [ ! -f /casper.vars ]; then
    touch /casper.vars
fi

parse_cmdline()
{
    for x in $(cat /proc/cmdline); do
        case $x in
            union=*)
                export UNIONFS="${x#union=}";;
            ignore_uuid)
                IGNORE_UUID="Yes" ;;
	    live-rootfs=*)
	        LIVE_ROOTFS="${x#live-rootfs=}"
		export LIVE_ROOTFS
		echo "export LIVE_ROOTFS=\"$LIVE_ROOTFS\"" >> /etc/casper.conf ;;
            live-media-path=*)
                LIVE_MEDIA_PATH="${x#live-media-path=}"
                export LIVE_MEDIA_PATH
                echo "export LIVE_MEDIA_PATH=\"$LIVE_MEDIA_PATH\"" >> /etc/casper.conf ;;
            toram)
                export TORAM="Yes" ;;
            todisk=*)
                export TODISK="${x#todisk=}" ;;
        esac
    done
    if [ "${UNIONFS}" = "" ]; then
        export UNIONFS="unionfs"
    fi
}

is_casper_path()
{
    local path=$1

    if [ -d "$path/$LIVE_MEDIA_PATH" ]; then
        if [ "$(echo $path/$LIVE_MEDIA_PATH/*.squashfs)" != \
		"$path/$LIVE_MEDIA_PATH/*.squashfs" ]; then
            return 0
        fi
    fi
    return 1
}

matches_uuid()
{
    if [ "$IGNORE_UUID" ] || [ ! -e /conf/uuid.conf ]; then
        return 0
    fi
    local path="$1"
    local uuid="$(cat /conf/uuid.conf)"

    for try_uuid_file in "$path/.disk/casper-uuid"*; do
        [ -e "$try_uuid_file" ] || continue
        try_uuid="$(cat "$try_uuid_file")"
        if [ "$uuid" = "$try_uuid" ]; then
            return 0
        fi
    done
    return 1
}

get_backing_device()
{
    case "$1" in
        *.squashfs)
            echo $(setup_loop "$1" "loop" "/sys/block/loop*")
            ;;
        *)
            panic "Unrecognized casper filesystem: $1"
            ;;
    esac
}

mount_image_in_directory()
{
    local directory="$1"
    local rootmnt="$2"

    if [ ! -f "$directory/$LIVE_MEDIA_PATH/$LIVE_ROOTFS" ]; then
	    panic "Cannot find $directory/$LIVE_MEDIA_PATH/$LIVE_ROOTFS"
    fi

    setup_unionfs "$directory/$LIVE_MEDIA_PATH" "$rootmnt"
}

is_nice_device()
{
    local sysfs_path="${1#/sys}"

    if /lib/udev/path_id "${sysfs_path}" | egrep -q "ID_PATH=(usb|pci-[^-]*-(ide|scsi|usb)|platform-orion-ehci|platform-
mmc|platform-mxsdhci)"; then
        return 0
    fi
    if echo ${sysfs_path} | grep -q "^/block/dm-"; then
        return 0
    fi
    return 1
}

copy_live_to()
{
    local copyfrom="${1}"
    local copytodev="${2}"
    local copyto="${copyfrom}_swap"
    local size freespace mount_options free_string fstype dev

    size=$(fs_size "" ${copyfrom} "used")

    if [ "${copytodev}" = "ram" ]; then
        # copying to ram:
        freespace=$(awk '/^MemFree:/{f=$2} /^Cached:/{c=$2} END{print f+c}' /proc/meminfo)
        mount_options="-o size=${size}k"
        free_string="memory"
        fstype="tmpfs"
        dev="/dev/shm"
    else
        # it should be a writable block device
        if [ -b "${copytodev}" ]; then
            dev="${copytodev}"
            free_string="space"
            fstype=$(get_fstype "${dev}")
            freespace=$(fs_size "${dev}")
        else
            [ "$quiet" != "y" ] && \
		log_warning_msg "${copytodev} is not a block device."
            return 1
        fi
    fi
    if [ "${freespace}" -lt "${size}" ] ; then
        [ "$quiet" != "y" ] && log_warning_msg "Not enough free ${free_string} (${freespace}k > ${size}k) to copy live media in ${copytodev}."
        return 1
    fi

    # begin copying..
    mkdir "${copyto}"
    echo "mount -t ${fstype} ${mount_options} ${dev} ${copyto}"
    mount -t "${fstype}" ${mount_options} "${dev}" "${copyto}"
    # "cp -a" from busybox also copies hidden files
    cp -a ${copyfrom}/* ${copyto}
    umount ${copyfrom}
    mount -r -o move ${copyto} ${copyfrom}
    rmdir ${copyto}
    return 0
}

setup_unionfs()
{
    local image_directory="$1"
    local rootmnt="$2"
    local croot rofsstring rofslist roopt image imagename backdev
    local fstype cowdevice cow_fstrype cow_mountopt

    case ${UNIONFS} in
        aufs|unionfs)
            modprobe "${MP_QUIET}" -b ${UNIONFS} || true
            ;;
    esac

    # run-init can't deal with images in a subdir, but we're going to
    # move all of these away before it runs anyway.  No, we're not,
    # put them in / since move-mounting them into / breaks mono and
    # some other apps.
    croot="/"

    # Let's just mount the read-only file systems first
    rofsstring=""
    rofslist=""
    if [ "${UNIONFS}" = "aufs" ]; then
        roopt="rr"
    else
        roopt="ro"
    fi

    mkdir -p "${croot}"
    image="${image_directory}/${LIVE_ROOTFS}"
    imagename=$(basename "$image")
    backdev=$(get_backing_device "$image")
    fstype=$(get_fstype "${backdev}")
    if [ "${fstype}" = "unknown" ]; then
    	panic "Unknown file system type on ${backdev} (${image})"
    fi
    mkdir -p "${croot}/${imagename}"
    mount -t "${fstype}" -o ro,noatime "${backdev}" "${croot}/${imagename}" \
	|| panic "Can not mount $backdev ($image) on ${croot}/${imagename}"

    rofsstring="${croot}/${imagename}=${roopt}:${rofsstring}"
    rofslist="${croot}/${imagename} ${rofslist}"
    rofsstring=${rofsstring%:}

    mkdir -p /cow
    cowdevice="tmpfs"
    cow_fstype="tmpfs"
    cow_mountopt="rw,noatime,mode=755"

    mount -t ${cow_fstype} -o ${cow_mountopt} ${cowdevice} \
	/cow || panic "Can not mount $cowdevice on /cow"
    mount -t ${UNIONFS} -o noatime,dirs=/cow=rw:$rofsstring \
	${UNIONFS} "$rootmnt" || panic "${UNIONFS} mount failed"

    # move the first mount.
    mkdir -p "${rootmnt}/rofs"
    mount -o move ${croot}${imagename} "${rootmnt}/rofs"
}

check_dev()
{
    local sysdev="${1}"
    local devname="${2}"
    local skip_uuid_check="${3}"
    local loopdevname devuid

    if [ -z "${devname}" ]; then
        devname=$(sys2dev "${sysdev}")
    fi

    if [ -d "${devname}" ]; then
        mount -o bind "${devname}" $mountpoint || continue
        if is_casper_path $mountpoint; then
            echo $mountpoint
            return 0
        else
            umount $mountpoint
        fi
    fi

    [ -e "$devname" ] || continue

    if [ -n "${LIVEMEDIA_OFFSET}" ]; then
        loopdevname=$(setup_loop "${devname}" "loop" "/sys/block/loop*" "${LIVEMEDIA_OFFSET}")
        devname="${loopdevname}" 
    fi

    fstype=$(get_fstype "${devname}")
    if is_supported_fs ${fstype}; then
        devuid=$(blkid -o value -s UUID "$devname")
        [ -n "$devuid" ] && grep -qs "\<$devuid\>" $tried && continue
        mount -t ${fstype} -o ro,noatime "${devname}" $mountpoint || continue
        [ -n "$devuid" ] && echo "$devuid" >> $tried
        if is_casper_path $mountpoint && \
           ([ "$skip_uuid_check" ] || matches_uuid $mountpoint); then
            echo $mountpoint
            return 0
        else
            umount $mountpoint
        fi
    fi

    if [ -n "${LIVEMEDIA_OFFSET}" ]; then
        losetup -d "${loopdevname}"
    fi
    return 1
}

find_livefs()
{
    local timeout="${1}"
    local devname fstype dev

    # first look at the one specified in the command line
    if [ ! -z "${LIVEMEDIA}" ]; then
        if check_dev "null" "${LIVEMEDIA}" "skip_uuid_check"; then
            return 0
        fi
    fi
    # don't start autodetection before timeout has expired
    if [ -n "${LIVEMEDIA_TIMEOUT}" ]; then
        if [ "${timeout}" -lt "${LIVEMEDIA_TIMEOUT}" ]; then
            return 1
        fi
    fi
    # or do the scan of block devices
    for sysblock in \
	$(echo /sys/block/* | tr ' ' '\n' | grep -vE "/(loop|ram|fd)"); do
        devname=$(sys2dev "${sysblock}")
        [ -e "$devname" ] || continue
        fstype=$(get_fstype "${devname}")
        if /lib/udev/cdrom_id ${devname} > /dev/null; then
            if check_dev "null" "${devname}" ; then
                return 0
            fi
        elif is_nice_device "${sysblock}" ; then
            for dev in $(subdevices "${sysblock}"); do
                if check_dev "${dev}" ; then
                    return 0
                fi
            done
        elif [ "${fstype}" = "squashfs" ]; then
            # This is an ugly hack situation, the block device has
            # an image directly on it.  It's hopefully
            # casper, so take it and run with it.
            ln -s "${devname}" "${devname}.${fstype}"
            echo "${devname}.${fstype}"
            return 0
        fi
    done
    return 1
}

mountroot()
{
    local i livefs_root live_dest

    parse_cmdline
    wait_for_udev 10

    maybe_break casper-premount
    log_begin_msg "Running /scripts/casper-premount"
    run_scripts /scripts/casper-premount
    log_end_msg

    # Scan local devices for the image
    i=0
    while [ "$i" -lt 10 ]; do
        livefs_root=$(find_livefs $i)
        [ -n "${livefs_root}" ] && break
        sleep 1
        i="$(($i + 1))"
    done

    if [ -z "${livefs_root}" ]; then
        panic "Unable to find a medium containing a live file system"
    fi

    if [ "${TORAM}" ]; then
        live_dest="ram"
    elif [ "${TODISK}" ]; then
        live_dest="${TODISK}"
    fi
    if [ "${live_dest}" ]; then
	log_begin_msg "Copying live_media to ${live_dest}"
        copy_live_to "${livefs_root}" "${live_dest}"
        log_end_msg
    fi

    mount_image_in_directory "${livefs_root}" "${rootmnt}"

    maybe_break casper-bottom
    log_begin_msg "Running /scripts/casper-bottom"
    run_scripts /scripts/casper-bottom
    log_end_msg
}