#!/bin/bash

set -o errexit

# Ensure /tmp exists and has the proper permissions before
# checking for security updates
# https://github.com/digitalocean/marketplace-partners/issues/94
if [[ ! -d /tmp ]]; then
  mkdir /tmp
fi
chmod 1777 /tmp

if [ -n "$(command -v yum)" ]; then
  yum update -y
  yum clean all
elif [ -n "$(command -v apt-get)" ]; then
  export DEBIAN_FRONTEND=noninteractive
  apt-get -y update
  apt-get -o Dpkg::Options::="--force-confold" upgrade -q -y --force-yes
  apt-get -y autoremove
  apt-get -y autoclean
fi

rm -rf /tmp/* /var/tmp/*
history -c
cat /dev/null > /root/.bash_history
unset HISTFILE
find /var/log -mtime -1 -type f -exec truncate -s 0 {} \;
rm -rf /var/log/*.gz /var/log/*.[0-9] /var/log/*-????????
rm -rf /var/lib/cloud/instances/*
rm -f /root/.ssh/authorized_keys /etc/ssh/*key*
rm -f /var/log/kern.log
rm -f /var/log/ufw.log
rm -f /var/log/auth.log
touch /etc/ssh/revoked_keys
chmod 600 /etc/ssh/revoked_keys

# Securely erase the unused portion of the filesystem
GREEN='\033[0;32m'
NC='\033[0m'
printf "\n${GREEN}Writing zeros to the remaining disk space to securely
erase the unused portion of the file system.
Depending on your disk size this may take several minutes.
The secure erase will complete successfully when you see:${NC}
    dd: writing to '/zerofile': No space left on device\n
Beginning secure erase now\n"

dd if=/dev/zero of=/zerofile &
  PID=$!
  while [ -d /proc/$PID ]
    do
      printf "."
      sleep 5
    done
sync; rm /zerofile; sync
cat /dev/null > /var/log/lastlog; cat /dev/null > /var/log/wtmp