#!/bin/sh

# Where this script exists
dir=$(dirname "$(readlink -f "$0")")

# MOTD is worthless IMO
cat /dev/null > /etc/motd

# Embiggen tty console to a more cromulant size
sed -i 's/^.*GRUB_GFXMODE=640x480.*$/GRUB_GFXMODE=1024x768\nGRUB_GFXPAYLOAD_LINUX=keep/' /etc/default/grub
update-grub

# Because that's how I roll...
sed -i 's/^.*PermitRootLogin.*$/PermitRootLogin yes/' /etc/ssh/sshd_config

# (Make your own authorized_keys file and uncomment)
#mkdir -p /root/.ssh
#cp "$dir/authorized_keys" /root/.ssh/

# Install firstboot setup script
cp "$dir/firstboot" /root/
cp "$dir/profile" /root/.profile

# Install update-issue script to get eth0 IP and MAC addr on login prompt
cp "$dir/update-issue" /etc/network/if-post-down.d/
cp "$dir/update-issue" /etc/network/if-up.d/

# Gotta be current, yo!
apt-get update && apt-get dist-upgrade -y

# No system would be complete without:
apt-get install -y \
        sysstat strace htop \
        iperf iperf3 nload tcpdump ethtool \
        curl tmux rsync sshfs git ntp \
        unzip p7zip-full unrar-free \
        libpam-systemd dbus open-vm-tools

# Delete apt cache to save space
apt-get clean

# Zero out block-backed swap devices, and just delete file-backed swap devices.
# Disk space consumed by files will be taken care of by zerofree run after this
# script is run.
swapoff -a
for s in $(grep swap /etc/fstab | awk '{print $1}') ; do
        if [ -b "$s" ] ; then
                dd if=/dev/zero of="$s" bs=512
        elif [ -f "$s" ] ; then
                rm "$s"
        fi
done
# Clean up /var/log/
rm -rf /var/log/installer
find /var/log/ -type f -name '*.gz' -delete
find /var/log/ -type f -name '*.[[:digit:]]*' -delete
find /var/log/ -type f -exec grep -Iq . {} \; -and -exec truncate {} --size 0 \;

# Shhh, none of this ever happened...
find /root/.ssh/ ! -path /root/.ssh/ ! -name 'authorized_keys' -delete
rm -f /root/.bash_history

### MANUAL STEPS

# Delete prep files and power off

# Mount disk (eg by booting from a live cd) and run zerofree on all ext4-formatted block devices

# Power system off, remove any attached disk images, and capture an OVA of it. My OVA is < 450M