chroot_build.sh

#!/bin/bash

set -e                  # exit on error
set -o pipefail         # exit on pipeline error
set -u                  # treat unset variable as error
#set -x

ELECTRUM_VERSION="4.0.9"

SCRIPT_DIR="$(dirname "$(readlink -f "$0")")"

CMD=(setup_host install_pkg finish_up)

function help() {
    # if $1 is set, use $1 as headline message in help()
    if [ -z ${1+x} ]; then
        echo -e "This script builds EROAS (Electrum-Running-On-A-Stick)"
        echo -e
    else
        echo -e $1
        echo
    fi
    echo -e "Supported commands : ${CMD[*]}"
    echo -e
    echo -e "Syntax: $0 [start_cmd] [-] [end_cmd]"
    echo -e "\trun from start_cmd to end_end"
    echo -e "\tif start_cmd is omitted, start from first command"
    echo -e "\tif end_cmd is omitted, end with last command"
    echo -e "\tenter single cmd to run the specific command"
    echo -e "\tenter '-' as only argument to run all commands"
    echo -e
    exit 0
}

function find_index() {
    local ret;
    local i;
    for ((i=0; i<${#CMD[*]}; i++)); do
        if [ "${CMD[i]}" == "$1" ]; then
            index=$i;
            return;
        fi
    done
    help "Command not found : $1"
}

function check_host() {
    if [ $(id -u) -ne 0 ]; then
        echo "This script should be run as 'root'"
        exit 1
    fi

    export HOME=/root
    export LC_ALL=C
}

function setup_host() {
    echo "=====> running setup_host ..."

    echo "EROAS" > /etc/hostname

    # we need to install systemd first, to configure machine id
    apt-get update
    apt-get install -y libterm-readline-gnu-perl systemd-sysv

    #configure machine id
    dbus-uuidgen > /etc/machine-id
    ln -fs /etc/machine-id /var/lib/dbus/machine-id

    # don't understand why, but multiple sources indicate this
    dpkg-divert --local --rename --add /sbin/initctl
    ln -s /bin/true /sbin/initctl
}

function install_wallet() {
    echo "=====> running install_wallet ..."
    apt-get install -y tor
    apt-get install -y cryptmount
    apt-get install -y sshpass

    # we just download single executable image
    pushd /usr/local/bin
    wget https://download.electrum.org/$ELECTRUM_VERSION/electrum-$ELECTRUM_VERSION-x86_64.AppImage
    chmod +x electrum-$ELECTRUM_VERSION-x86_64.AppImage
    ln -sf electrum-$ELECTRUM_VERSION-x86_64.AppImage electrum
    popd 

    # setup a basic firewall for now, no incoming, only DNS and Tor outgoing.
    # on AWS, IPV6 is not enabled and will barf if not disabled
    sed -i -e "s#IPV6=yes#IPV6=no#" /etc/default/ufw
    ufw default deny incoming
    ufw default deny outgoing
    ufw allow out 53

    # enable on boot up, but not now for remote build
    sed -i -e "s#ENABLED=no#ENABLED=yes#" /etc/ufw/ufw.conf
}

function install_pkg() {
    echo "=====> running install_pkg ... will take a long time ..."
    apt-get -y upgrade

    # install live linux packages
    apt-get install -y ubuntu-standard casper lupin-casper laptop-detect os-prober linux-generic

    # install networking packages
    apt-get install -y \
        network-manager \
        resolvconf \
        net-tools \
        wireless-tools \
        wpagui \
        locales

    # install wifi driver for macbook, 
    # see https://askubuntu.com/questions/55868/installing-broadcom-wireless-drivers
    apt-get install -y firmware-b43-installer
    apt-get install -y bcmwl-kernel-source 

    # install graphics and desktop
    apt-get install -y xfce4
    
    # install some utils
    apt-get install -y vim less curl apt-transport-https xfce4-screenshooter

    # install firefox
    apt-get install -y firefox

    # disable cups by default (TODO: not working??)
    systemctl disable cups

    # install electrum wallet and related pkgs
    install_wallet

    # remove unneeded packages
    apt-get remove -y cups
    apt-get autoremove -y

    # configure pkgs
    dpkg-reconfigure locales
    dpkg-reconfigure resolvconf

    # network manager
    cat <<EOF > /etc/NetworkManager/NetworkManager.conf
[main]
rc-manager=resolvconf
plugins=ifupdown,keyfile
dns=dnsmasq

[ifupdown]
managed=false
EOF
    dpkg-reconfigure network-manager

    # strange, without apt-get clean, screen is dark, why??
    apt-get clean -y
}

function finish_up() { 
    echo "=====> finish_up"

    # truncate machine id (why??)
    truncate -s 0 /etc/machine-id

    # remove diversion (why??)
    rm /sbin/initctl
    dpkg-divert --rename --remove /sbin/initctl

    rm -rf /tmp/* ~/.bash_history
}

# =============   main  ================

check_host

# check number of args
if [[ $# == 0 || $# > 3 ]]; then help; fi

# loop through args
dash_flag=false
start_index=0
end_index=${#CMD[*]}
for ii in "$@";
do
    if [[ $ii == "-" ]]; then
        dash_flag=true
        continue
    fi
    find_index $ii
    if [[ $dash_flag == false ]]; then
        start_index=$index
    else
        end_index=$(($index+1))
    fi
done
if [[ $dash_flag == false ]]; then
    end_index=$(($start_index + 1))
fi

# loop through the commands
for ((ii=$start_index; ii<$end_index; ii++)); do
    ${CMD[ii]}
done

echo "$0 - Initial build is done!"