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https://github.com/m7a/lp-mahalt

MDVL System Shutdown Command
https://github.com/m7a/lp-mahalt

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MDVL System Shutdown Command

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README 

        
---

section: 11

x-masysma-name: mahalt

title: System Shutdown Script

date: 2020/09/20 01:30:30

lang: en-US

author: ["Linux-Fan, Ma_Sys.ma ([email protected])"]

keywords: ["script", "mdvl", "mahalt", "sudo"]

x-masysma-version: 1.0.0

x-masysma-repository: https://www.github.com/m7a/lp-mahalt

x-masysma-website: https://masysma.net/11/mahalt.xhtml

x-masysma-owned: 1

x-masysma-copyright: |

  Copyright (c) 2012, 2017, 2020 Ma_Sys.ma.

  For further info send an e-mail to [email protected].

---

Name

====



`mahalt` -- Shutdown system after invoking scripts.



Synposis

========



	mahalt [-f] [-r]



Description

===========



This script is intended to serve as a means of shutting down desktop systems.



The following features are added compared to a direct invocation of

`systemctl poweroff` (or similar):



 * Regular users should be able to invoke shutdown. By including

   sudo configuration and a means to automatically restart the script with sudo,

   it becomes possible for users to conveniently invoke the script.

 * To perform backups and other tasks that are best run individually without

   other services interfering, directory `/usr/lib/mahalt.d` is consulted for

   executable files. They are executed in the order reported by `find | sort`.

 * Before invoking the actual shutdown command, all Java applications are sent

   a `SIGTERM` and `sync` is called.

 * If immediately before invoking the actual shutdown, `/tmp/nohalt` exists,

   the process is cancelled. This feature can be used by the scripts in

   `/usr/lib/mahalt.d` or by users on the local machine who wish to interrupt

   the shutdown process without cancelling any of the running hooks from

   `/usr/lib/mahalt.d`.



## Notes on hooks



 * All executables form `/usr/lib/mahalt.d` are passed parameter `--by-mahalt`.

 * Outputs from hooks are written to file `/var/log/mahalt` and can thus be

   analyzed after the next reboot.



## WARNING: Sudo Configuration Included



This package includes a sudoers configuration allowing user `linux-fan` to

run the `mahalt` command which makes a `shutdown`-style command available to a

user. Beware that this is not expected to be a safe operation on servers as

regular users may not have physical access.



Options

=======



----  --------------------------------------------------------

`-f`  Fast -- skip execution of hooks from `/usr/lib/mahalt.d`

`-r`  Reboot instead of shutdown

----  --------------------------------------------------------



Rationale

=========



Similar to [vifm-ext(32)](../32/vifm-ext.xhtml), this script could have been

written in a manner that would have avoided the use of sudo/full-blown root

privileges for shutdown. Modern desktop environments use `dbus`-based calls

to invoke shutdown and the regular `systemctl poweroff` nowdays often works for

unprivileged users if systemd detects that they are the only ones logged in to

the local system.



This route was not taken for the following reasons:



 * Similar to mounting, the interface for “shutdown without root” often broke

   between release upgrades.

 * Ma_Sys.ma Backups run as root as to avoid the problem of files being

   inaccessible due to missing permissions. Hence, that part would need to

   run with sudo anyways.



Bugs

====



 * File names from below `/usr/lib/mahalt.d` may not contain spaces.

 * The `killall -s TERM java` invocation may stop some processes that should

   better be managed by their respective “supervisors” like systemd or docker...



See Also

========



[halt(8)](https://manpages.debian.org/buster/sysvinit-core/halt.8.en.html)