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bai4Iej2need

Member

From: Ortenau

Registered: 2021-04-25

Posts: 152  

xorg and wall (usr/bin/wall)

which wall
/usr/bin/wall

In ancient times (xdm, X11, fvmw*) I used to send myself messages out of scripts using /usr/bin/wall .
So I knew that e.g. a job is finished or some action to be taken.
This message showed up on all consoles and xterms or similar.

Recently I tested with wall to learn about progress of a script, but lightdm traps the message .
Does not show up on an open mate terminal.
Actually lightdm traps the message.
It shows then up on logout from Xorg and keeps the xserver to restart.
Manually I must do

service lightdm restart 

to get a fresh login window until I logout again. Same game.

wall used to inform users  from impending administration actions like shutdown or restart.
This function has been destroyed from the new habit of lightdm.

Apart from being a bug.
Now I have to find where this messages hang and they should be deleted on a restart of xserver.

It seems that the new generation of maintainers has no idea about multiuser systems.

Last edited by bai4Iej2need (Yesterday 17:47:18)

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The devil, you know, is better than the angel, you don't know. by a British Citizen, I don't know too good.
One generation abandons the enterprises of another like stranded vessels. By Henry David Thoreau, WALDEN, Economy. Line 236 (Gutenberg text Version)
broken by design :
https://bugs.debian.org/cgi-bin/bugrepo … bug=958390

Altoid

Member

Registered: 2017-05-07

Posts: 2,086  

Re: xorg and wall (usr/bin/wall)

Hello:

Never used [wall] or [lightdm].
I am a [SLiM] enthusiast on a single-user WS.

That said and only to see if an [AI] answer can be (?) useful (I do not like it nor do I use it, this is just a test), out of curiosity I searched with Google and it came up with this without giving me an option to avoid it:

Terms used: [lightdm traps wall message]

Reply:

If your system hangs, delays, or traps a wall broadcast message when LightDM is active, it is typically because LightDM's greeter session listens to standard system log channels or terminal broadcasts, but lacks a standard terminal emulator to output the text cleanly.

Why the Trap Happens

Greeter Isolation:
LightDM's greeter runs under its own isolated unprivileged account (lightdm). If a system event (like a scheduled shutdown) fires a wall message, the system tries to inject it into all open pseudo-terminals (/dev/pts/*).

TTY/STDOUT Redirection:
The lightdm user owns a sub-process session that grabs TTY streams. Because it lacks a proper graphical notification daemon to catch terminal broadcasts, the text stream can buffer natively or loop inside systemd's logs (journalctl -u lightdm)

There's more, but this may get you on your way.
I am not sure about getting it done while using [lightdm].

Best,

A.

Last edited by Altoid (Today 19:45:50)

fsmithred

Administrator

Registered: 2016-11-25

Posts: 2,959  

Re: xorg and wall (usr/bin/wall)

Turning off lightdm and using startx doesn't help. I still get the wall message on a console where I'm logged in but not in the desktop terminal.

Not sure if this helps. From 'man wall'

NOTES
       Some sessions, such as wdm(1x), that have in the beginning of utmp(5) ut_type data a ':' character will not get
       the message from wall. This is done to avoid write errors.