Provided by: molly-guard_0.4.4-2_all
molly-guard - guard against accidental shutdowns/reboots
shutdown [-hV] [--molly-guard-do-nothing] [-- script_options]
halt [-hV] [--molly-guard-do-nothing] [-- script_options]
reboot [-hV] [--molly-guard-do-nothing] [-- script_options]
poweroff [-hV] [--molly-guard-do-nothing] [-- script_options]
molly-guard attempts to prevent you from accidentally shutting down or
rebooting machines. It does this by injecting a couple of checks before
the existing commands: halt, reboot, shutdown, and poweroff. This
happens via scripts with the same names in /usr/sbin, so it only works
if you have /usr/sbin before /sbin in your PATH!
Before molly-guard invokes the real command, all scripts in
/etc/molly-guard/run.d/ have to run and exit successfully; else, it
aborts the command. run-parts(1) is used to process the directory.
molly-guard passes any script_options to the scripts, and also
populates the environment with the following variables:
o MOLLYGUARD_CMD - the actual command invoked by the user.
o MOLLYGUARD_DO_NOTHING - set to 1 if this is a demo-run.
o MOLLYGUARD_SETTINGS - the path to a shell script snippet which
scripts can source to obtain settings.
molly-guard prints the contents of /etc/molly-guard/messages.d/COMMAND
or /etc/molly-guard/messages.d/default to the console, if either
exists. This is due to /etc/molly-guard/run.d/10-print-message.
GUARDING SSH SESSIONS
molly-guard was primarily designed to shield SSH connections. This
functionality (which should arguably be provided by the openssh-server
package) is implemented in /etc/molly-guard/run.d/30-query-hostname.
This script first tests whether the command is being executed from a
tty which has been created by sshd. It also checks whether the variable
SSH_CONNECTION is defined. If any of these tests are successful, test
script queries the user for the machine's hostname, which should be
sufficient to prevent the user from doing something by accident.
You can pass the --pretend-ssh script option to molly-guard to pretend
that those tests succeeds. Alternatively, setting ALWAYS_QUERY_HOSTNAME
in /etc/molly-guard/rc causes the script to always query.
The following situations are still UNGUARDED. If you can think of ways
to protect against those, please let me know!
o running sudo within screen or screen within sudo; sudo eats the
SSH_CONNECTION variable, and screen creates a new pty.
o executing those command in a remote terminal window, that is a
XTerm started on a remote machine but displaying on the local X
You have been warned. You can use the --molly-guard-do-nothing switch
to prevent anything from happening, e.g. halt
Cause molly-guard to print the command which would be executed,
after processing all scripts, instead of executing it.
Display usage information.
Display version information.
shutdown(8), halt(1), reboot(8), poweroff(8).
molly-guard is copyright by martin f. krafft. Andrew Ruthven came up
with the idea of using the scripts directory and submitted a patch,
which I modified a bit.
This manual page was written by martin f. krafft <firstname.lastname@example.org>.
Permission is granted to copy, distribute and/or modify this document
under the terms of the Artistic License 2.0
Copyright (C) 2008 martin f. krafft
Apr 19, 2008 MOLLY-GUARD(8)