#!/bin/bash
# Copyright (C) 2016 Ian Kelling

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at

#     http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

set -eE -o pipefail
trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" returned $?" >&2' ERR

[[ $EUID == 0 ]] || exec sudo -E "${BASH_SOURCE[0]}" "$@"

dest=/root/.ssh

# leftover
if [[ -L $dest ]]; then
  rm $dest
fi
mkdir -p $dest
chmod 700 $dest

user=$(id -un)
if [[ $SUDO_USER ]]; then
  user=$SUDO_USER
fi

user_ssh_dir=$(eval echo ~$user)/.ssh
if [[ ! -s $user_ssh_dir/authorized_keys ]]; then
  echo missing $user_ssh_dir/authorized_keys. bad sign. bailing >&2
  exit 1
fi

# remove broken links, or else rsync has error about them.
find $user_ssh_dir -xtype l -exec rm '{}' \;
# -t times, so it won't rewrite the file every time,
# -L resolve links
rsync -rtL --delete $user_ssh_dir/ $dest
chown -R root:root /root/.ssh


d=/etc/initramfs-tools
if [[ -e $d ]] && ! diff -q /root/.ssh/authorized_keys $d/root/.ssh/authorized_keys &>/dev/null; then
  mkdir -p $d/root/.ssh /etc/dropbear-initramfs
  chmod 700 $d/root $d/root/.ssh
  cp -p /root/.ssh/authorized_keys $d/root/.ssh/authorized_keys
  cp -p /root/.ssh/authorized_keys /etc/dropbear-initramfs
  update-initramfs -u -k all
fi