#!/busybox sh

NORMAL="\\033[0m" # white on black, or whatever your terminal is
FAIL="\\033[1;31m" # red foreground
OK="\\033[1;32m" # green foreground
INFO="\\033[1;34m" # blue foreground

alias tar='/busybox tar -C /roottmpfs -xpf -'
alias bzcat='/busybox bzcat'
alias xzcat='/busybox xzcat'
alias mount='/busybox mount'
alias umount='/busybox umount'

die() {
    echo ""
    echo -e "${FAIL}Shit broke! Panic shell!${NORMAL}"
    echo ""
    /busybox --install -s
    exec /bin/sh
}

info() {
    echo -en "-${INFO}|${NORMAL}-" ${@} "... "
}

isok() {
    if [[ $1 -eq 0 ]]; then
        echo -e "${INFO}[ ${OK}OK${INFO} ]${NORMAL}"
    else
        echo -e "${INFO}[ ${FAIL}FUCK${INFO} ]${NORMAL}"
        die
    fi
}

info "disabling console blanking, hopefully"
echo -e '\033[9;0]\033[14;0]' > /dev/console

info "waiting for usb devices to settle"
echo ""
for i in 10 9 8 7 6 5 4 3 2 1 0; do
    echo -en ${i}'\r'
    /busybox sleep 1
done
echo ""
isok 0

info "mounting devtmpfs"
/busybox mount -n -t devtmpfs devtmpfs ./dev
isok $?

info "mounting proc"
/busybox mount -n -t proc proc ./proc
isok $?

info "getting root tmpfs size"
for var in $(cat /proc/cmdline); do
    if [[ ${var/=*} = rootfs_size ]]; then
        size=${var/*=}
    fi
done
if [[ -z ${size} ]]; then
    info "going with default: 4G"
    size="4G"
fi
isok 0

info "trying to mount root tmpfs"
/busybox mount -n -o size=${size} -t tmpfs roottmpfs /roottmpfs
isok $?

info "checking if the user wants to use a different init"
for var in $(cat /proc/cmdline); do
    if [[ ${var/=*} = init ]]; then
        init="${var/*=}"
        info "user wants ${init}"
    fi
done
if [[ -z "${init}" ]]; then
    info "no; default: /sbin/init"
    init="/sbin/init"
    isok $?
fi

info "checking for network configuration on kernel commandline"
echo ""
for var in $(cat /proc/cmdline); do
    if [[ ${var/=*} = ipcmd ]]; then
        # Split the "value" part of this parameter into parts, with "," as
        # separators and then use them for constructing iproute2 commandline.
        # Don't do any input validation; escape to the shell if things break.
        # Do it in a subshell to prevent IFS change leak.
        (
            IFS=","
            set -- ${var/*=}
            info "ip ${@}"
            /busybox ip ${@}
            isok $?
        )
    fi
done

# syntax examples:
# rootfs_part=uuid|f822d881-d88a-4200-a9cf-6986c5a3e69a/some_directory/file|xzcat|tar
#  -> findfs -> mount -> xzcat | tar
# rootfs_part=url|http://10.3.13.37/url.tar.bz2|bzcat|tar
#  -> wget -O - | bzcat | tar
# You might find bugs & dragons here; patches accepted.
info "looking for root filesystem tarballs"
echo ""
for var in $(cat /proc/cmdline); do
    if [[ "${var/=*}" = rootfs_part ]]; then
        part="${var/*=}"
        info "found ${part}"
        # uuid or url
        url_type="${part/|*}"
        # url + transformations
        url="${part#${url_type}|}"
        # transformations
        transformations="${url#*|}"
        # url
        url="${url/|*}"
        (
            if [[ ${url_type} = "uuid" ]]; then
                uuid="${url%%/*}"
                filepath="${url#*/}"

                info "mounting $(findfs UUID="${uuid}") on /mnt"
                mount -n -o ro "$(findfs UUID="${uuid}")" /mnt
                isok $?

                info "unpacking /mnt/${filepath}"
                echo ""
                /pv "/mnt/${filepath}" | eval ${transformations}
                isok $?

                info "unmounting"
                umount -n /mnt
                isok $?
            else
                info "wgetting ${url} and transforming it on the fly"
                /busybox wget -O - "${url}" | eval ${transformations}
                isok $?
            fi
        )
    fi
done

info "unmounting /dev"
/busybox umount -n /dev
isok $?

info "unmounting /proc"
/busybox umount -n /proc
isok $?

info "checking if /roottmpfs/${init} exists"
[[ -e /roottmpfs/${init} ]]
isok $?

info "trying to switch root"
exec /busybox switch_root /roottmpfs /sbin/init

echo ""
echo -e "${FAIL}we should not reach this place! here be dragons!${NORMAL}"
echo ""

die