Zero-OS VirtualBox Bootdisk (offline tool, doesn't download kernel on each boot)

zos-vbox-offline.sh

#!/bin/bash
set -e

usage() {
    echo "Zero-OS VirtualBox Offline Bootdisk Tool"
    echo ""
    echo "  ./zos-vbox-offline.sh <image-file.vdi> [branch] [zerotier] [kernel arguments]"
    echo ""
    echo "All arguments except image-file are optional, see default value below"
    echo ""
    echo " - Image file: filename of the rawdisk you'll need to boot (eg: /tmp/zos.img)"
    echo ""
    echo " - Branch is the kernel branch revision (see bootstrap to get a list)"
    echo "   Default: development"
    echo ""
    echo " - Zerotier argument is zerotier network id to join on boot"
    echo "   Default: 0 (no zerotier network)"
    echo ""
    echo " - Kernel arguments needs to be set as single argument (use quotes if you"
    echo "   want to use multiple arguments)"
    echo "   Default: 'development debug'"
    echo ""
    exit 1
}

checkcmd() {
    which $1 2>&1 > /dev/null || (echo "[-] cannot find '$1' command required"; exit 1)
}

prepare() {
    echo "[+] checking system dependencies"

    [[ "$UID" != "0" ]] && (echo "[-] please run as root (need to mount stuff)"; exit 1)

    # syslinux root is not at same location on different distribution
    syslinuxroot="/usr/lib/syslinux"

    if [ ! -d ${syslinuxroot} ]; then
        syslinuxroot="/usr/share/syslinux"

        if [ ! -d ${syslinuxroot} ]; then
            echo "[-] cannot find syslinux data path"
            exit 1
        fi
    fi

    checkcmd mkfs.ext2
    checkcmd wget
    checkcmd sfdisk
    checkcmd losetup

    bootstrap="https://bootstrap.grid.tf"
}

mkdisk() {
    echo "[+] removing previous possible image disk file"
    rm -rf ${imagefile}.raw ${imagefile}

    echo "[+] creating and mounting disk image"
    truncate -s 128M ${imagefile}.raw

    # create linux (type 83) partition
    echo ',,83;' | sfdisk -q ${imagefile}.raw

    # mark partition 1 active
    sfdisk -q -A ${imagefile}.raw 1

    # mounting image as loop device
    loopdev=$(losetup -f --show -P ${imagefile}.raw)

    echo "[+] loop device populated: ${loopdev}"
}

mkdiskfs() {
    echo "[+] creating disk partition"
    mkfs.ext2 -q ${loopdev}p1
}

mounter() {
    echo "[+] creating temporary working directory"
    workdir=$(mktemp -d)

    echo "[+] mounting disk to: ${workdir}"
    mount ${loopdev}p1 ${workdir}
}

download() {
    echo "[+] downloading kernel file"
    url="${bootstrap}/kernel/zero-os-${branch}.efi"
    wget -q --show-progress -O ${workdir}/zero-os-kernel $url || (echo "[-] cannot download: $url"; exit 1)
}

bootloader() {
    echo "[+] installing bootmanager"
    extlinux --install ${workdir} 2> /dev/null
    cat ${syslinuxroot}/mbr.bin > ${loopdev}

    echo "[+] writing configuration file"
    extconf="${workdir}/extlinux.conf"

    echo "DEFAULT zos" > $extconf
    echo "LABEL zos" >> $extconf
    echo "    KERNEL /zero-os-kernel" >> $extconf
    echo "    APPEND $kargs" >> $extconf
}

convert() {
    echo "[+] converting disk into vdi file"
    sync
    VBoxManage convertdd ${loopdev} ${imagefile} --format VDI 2> /dev/null
}

cleaner() {
    echo "[+] unmounting stuff and cleaning"

    umount ${workdir}
    rm -rf ${workdir} ${imagefile}.raw

    losetup -d ${loopdev}
}

main() {
    # display usage on --help argument
    [[ "$1" == "--help" ]] && usage

    echo "[+] initializing virtualbox offline bootloader"

    prepare

    imagefile=$1
    branch=${2:-development}
    zerotier=${3:-0}
    kargs=${4:-development debug}

    echo "[+] "
    echo "[+] image file: $imagefile"
    echo "[+] zero-os branch: $branch"
    echo "[+] zerotier network: $zerotier"
    echo "[+] kernel arguments: $kargs"
    echo "[+] syslinux path: $syslinuxroot"
    echo "[+] bootstrap server: $bootstrap"
    echo "[+] "

    mkdisk
    mkdiskfs
    mounter
    download
    bootloader
    convert
    cleaner

    echo "[+] "
    echo "[+] zero-os virtualbox bootdisk ready: $imagefile"
}

main $@