#!/bin/sh
#
# shutdown -- wrapper script to prevent erroneous shutdowns via SSH
#
# Copyright © martin f. krafft <madduck@madduck.net>
# Released under the terms of the Artistic Licence 2.0
#
# $Id: shutdown 299 2006-10-16 14:40:47Z madduck $
#
set -eu

ME=molly-guard

CMD="${0##*/}"
EXEC="/sbin/$CMD"

case "$CMD" in
  halt|reboot|shutdown)
    if [ ! -f $EXEC ]; then
      echo "E: $ME: not a regular file: $EXEC" >&2
      exit 4
    if [ ! -x $EXEC ]; then
      echo "E: $ME: not an executable: $EXEC" >&2
      exit 3
    fi
    ;;
  *)
    echo "E: $ME: unsupported command: $CMD" >&2
    exit 1
    ;;
esac
ARGS="$@"

do_real_cmd()
{
  exec $EXEC "$ARGS"
}

# require $SSH_CONNECTION to be set, indicates an SSH session
[ -n "${SSH_CONNECTION:-}" ] || do_real_cmd
# require an interactive terminal connected to stdin
test -t 0                    || do_real_cmd
# pass through help commands
case "$CMD $ARGS" in
  'shutdown*-c'|'*-h') do_real_cmd;;
  *) :;;
esac

echo -n "$ME: SSH session detected, type in hostname of the machine to $CMD: "
read HOSTNAME_USER

HOSTNAME="$(hostname)"

if [ "$HOSTNAME_USER" != "$HOSTNAME" ]; then
  echo "Good thing I asked; I won't $CMD $HOSTNAME ..."
  exit 2
fi