#!/bin/bash

# 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