#!/bin/bash
# I, Ian Kelling, follow the GNU license recommendations at
# https://www.gnu.org/licenses/license-recommendations.en.html. They
# recommend that small programs, < 300 lines, be licensed under the
# Apache License 2.0. This file contains or is part of one or more small
# programs. If a small program grows beyond 300 lines, I plan to switch
# its license to GPL.

# Copyright 2024 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.


# I somehow ended up with an empty crypttab, and had to rescue my
# system. So, lets check for some basic validity.

if ! test "$BASH_VERSION"; then echo "error: shell is not bash" >&2; exit 1; fi
shopt -s inherit_errexit 2>/dev/null ||: # ignore fail in bash < 4.4
set -eE -o pipefail
trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" exit status: $?, PIPESTATUS: ${PIPESTATUS[*]}" >&2' ERR

debug=false
if [[ $1 ]]; then
  debug=true
fi
d() {
  if $debug; then
    printf "%s\n" "$*"
  fi
}

metric_dir=/var/lib/prometheus/node-exporter
mnt="$(findmnt -fn -o SOURCE /)"
case $mnt in
  /dev/mapper/crypt_dev_*)
    tmp=${mnt#/dev/mapper/}
    dev=${tmp%%\[*}
    if ! grep -qF $dev /etc/crypttab; then
      d $dev
      if [[ -e $metric_dir  ]]; then
        echo "crypttab_check 1" > $metric_dir/crypttab_check.prom
        exit 0
      fi
    fi
    ;;
esac
if [[ -e $metric_dir  ]]; then
  echo "crypttab_check 0" > $metric_dir/crypttab_check.prom
fi