#!/bin/sh # # shutdown -- wrapper script to prevent erroneous shutdowns via SSH # # Copyright © martin f. krafft # 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|poweroff) if [ ! -f $EXEC ]; then echo "E: $ME: not a regular file: $EXEC" >&2 exit 4 fi 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 usage() { cat <<-_eousage Usage: $ME [options] (shielding $EXEC) Instead of invoking $EXEC directly, $ME will run a number of checks to guard against accidental shutdowns/reboots. Some of the checks available are: - Prompt the user for the machine's if the current shell is a child of an SSH connection (or --pretend-ssh) has been given on the command line, if the shell is connected to an interactive terminal, and the actual command to execute is does not involve --help or is \`shutdown -c'. $ME will always interpose the prompt if the environment variable ALWAYS_MOLLY is set to '1'. This variable may be set in the file /etc/default/${ME} . - Print out a warning message with information about this host before the action takes place. You can use: /etc/molly-guard..message To print out a message specific to the command you're trying to use. Or: /etc/molly-guard.message For a general warning message. Only if the user satisfies all the checks will $ME take action. Specifying --molly-guard-do-nothing as argument to the command will make $ME echo the command it would execute rather than actually executing it. The actual command's help output follows: _eousage } ARGS= DO_NOTHING=0 CHECK_ARGS= for arg in "$@"; do case "$arg" in (*-molly-guard-do-nothing) DO_NOTHING=1;; (*-help) usage 2>&1 eval $EXEC --help 2>&1 exit 0 ;; (*-pretend-ssh) CHECK_ARGS="${CHECK_ARGS:+$CHECK_ARGS }--arg --pretend-ssh";; *) ARGS="${ARGS:+$ARGS }$arg";; esac done do_real_cmd() { if [ $DO_NOTHING -eq 1 ]; then echo "$ME: would run: $EXEC $ARGS" exit 0 else eval exec $EXEC "$ARGS" fi } if [ $DO_NOTHING -eq 1 ]; then echo "I: demo mode; $ME will not do anything due to --molly-guard-do-nothing." fi # pass through certain commands case "$CMD $ARGS" in (*shutdown\ *-c*) echo "I: executing $CMD $ARGS regardless of check results." do_real_cmd ;; esac run-parts --exit-on-error --arg $CMD $CHECK_ARGS /usr/share/molly-guard/checks.d # run-parts won't return to us if there are failures, but I'm paranoid. if [ $? == 0 ]; then do_real_cmd exit fi