setterm errors over ssh and when running in systemd service

[xnobodyx]

hello,

i can set the screen on a laptop to turn off after 1 minute with:

Code: Select all

setterm -blank 1 -powersave powerdown

i can't seem to get it to work over ssh. i am logged in locally on the machine to tty1 as verified by running $ w .

the solutions i've seen seem to indicate redirecting the command in the ssh session to tty1:

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sudo setterm -blank 1 -powersave powerdown >/dev/tty1

however this is returning the error:

"setterm: terminal xterm does not support --blank
setterm: cannot (un)set powersave mode: Inappropriate ioctl for device"

any help is greatly appreciated

[TrevorH]

i am logged in locally on the machine to tty1 as verified by running $ w .

I suspect someone is logged in as root on tty1. If you're in via ssh, unless you've done some "interesting" stuff then you'll be on pts/n. Try running who am i in your ssh session - does that say tty1? I'll also guess that if you run echo $TERM it says 'xterm'. Try TERM=linux setterm -blank 1 -powersave powerdown >/dev/tty1 (you will need to be root to run that).

[xnobodyx]

thanks for the quick reply. i was under the impression i would need to be logged in to tty1 locally on the machine to send the command from the ssh console to tty1?

(for the record, i run 'setterm -blank 0 -powersave off' locally on the machine before each test)

echo $TERM does return xterm in the ssh session.

TERM=linux setterm -blank 1 -powersave powerdown >/dev/tty1 returns the same "setterm: cannot (un)set powersave mode: Inappropriate ioctl for device" but it also appears to work, the screen powers off after one minute.

on a related note i am also trying to set up a systemd service to run the same command on boot...it seems to be working but outputs the same "setterm: cannot (un)set powersave mode: Inappropriate ioctl for device" error

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[Unit]
Description=Enable virtual console blanking and poweroff

[Service]
Type=oneshot
Environment=TERM=linux
StandardOutput=tty
TTYPath=/dev/console 
ExecStart=/usr/bin/setterm -blank 1 -powersave powerdown

[Install]
WantedBy=default.target

- Source: https://access.redhat.com/documentation ... m-settings
- Source: http://archlinux.2023198.n4.nabble.com/ ... 19304.html

[xnobodyx]

ah TERM=linux setterm -blank 1 -powersave powerdown >/dev/tty1 </dev/tty1 appears to have fixed it for the ssh session...does that seem right?

not sure how to implement that in the system service though...

[TrevorH]

Well we could probably much about experimenting with a unit file like that for a long time before we found the correct incantation so I think I'd write a 3 line shell script and stick it in /usr/local/bin and start that from the unit file...

[xnobodyx]

sadly i was trying that approach and it was failing, will try it again. thanks very much for your help

to clarify the screen does power off after the service is started, it just prints that error...

[xnobodyx]

unfortunately still getting the same 'Inappropriate ioctl for device' using the following script and service. to clarify if i login and run setterm -blank 1 -powersave powerdown there is no error:

/usr/local/bin/screenblank.sh:

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#!/bin/sh
TERM=linux setterm -blank 1 -powersave powerdown >/dev/console </dev/console

and /etc/systemd/system/screenblank.service:

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[Unit]
Description=Enable virtual console blanking and poweroff

[Service]
Type=oneshot
Environment=TERM=linux
StandardOutput=tty
TTYPath=/dev/console 
ExecStart=/usr/local/bin/screenblank.sh

[Install]
WantedBy=default.target

[TrevorH]

Run aureport -a and see if you have any entries in the audit log that match the time you last tried. If you do then use the number off the right hand end of that and plug it into ausearch -a nnnn and see if that helps explain it.

[xnobodyx]

unfortunately nothing in the audit log

[TrevorH]

Well the only difference I can see from the command you say worked when you ran it manually and the unit file is that the one that worked, you used /dev/tty1 and in your unit file you use /dev/console.