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UT_qx13s

Member

Registered: 2023-05-04

Posts: 7

[SOLVED] Log-out From Cron Stopped Working

Up until about a month ago I was able to successfully run the following command from cron:

pgrep -l xlock && $xfce4_session_logout --suspend

Now I get the following pop-up message each time it runs:

Received error while trying to log out, error was GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.xfce.SessionManager was not provided by any .service files

My xfce4-session version is 4.18.2.

Any idea what I need to change to get it working again?

It works when I test-run it from the command line, fwiw.

Last edited by UT_qx13s (2023-05-07 00:42:33)

ToZ

Administrator

From: Canada

Registered: 2011-06-02

Posts: 11,485

Re: [SOLVED] Log-out From Cron Stopped Working

Hello and welcome.

What does the variable $xfce4_session_logout contain?

Generally, cron doesn't know about your user session, and in this instance, it needs the dbus session bus address of your user session to run this command.

$ env | grep DBUS
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus

Cron entry:

* * * * * DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus xfce4-session-logout --logout

Not sure how it worked before though, too many unknowns (distro, updates, etc)

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UT_qx13s

Member

Registered: 2023-05-04

Posts: 7

Re: [SOLVED] Log-out From Cron Stopped Working

Hi ToZ,

What does the variable $xfce4_session_logout contain?

It's just a shell variable holding the absolute path to the executable.

Generally, cron doesn't know about your user session, and in this instance, it needs the dbus session bus address of your user session to run this command.

Makes sense. When I first wrote it, the job failed because DISPLAY wasn't defined.

My address appears set to a tmp file. Clearing tmp didn't fix it during my troubleshooting, which prompted me to post here for help. That's a hell of a GUID. Is that normal?

$ env | grep DBUS
DBUS_SESSION_BUS_ADDRESS=unix:path=/tmp/dbus-9ZyT0kppt5,guid=12bef731053d2ed3151c71006451aae5

Will try setting the address in cron. Thanks.

Not sure how it worked before though, too many unknowns (distro, updates, etc)

After some searching, it looks like it coincided with an xfce4-session upgrade from 4.18.0 to 4.18.2. The first error message it spat out was that my machine-id was corrupted (it was set to a series of j). Fixing that got me to the current error message.

ToZ

Administrator

From: Canada

Registered: 2011-06-02

Posts: 11,485

Re: [SOLVED] Log-out From Cron Stopped Working

Which distro are you using and is it systemd based? And how are you starting it (display manager or startx)?

dbus address on systemd changed a while back to use /run/user, but you need to run dbus-update-activation-environment during login.

Fixing that got me to the current error message.

Did you try changing your cron to reference this dbus session bus address?

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UT_qx13s

Member

Registered: 2023-05-04

Posts: 7

Re: [SOLVED] Log-out From Cron Stopped Working

Which distro are you using and is it systemd based?

The Great and Wonderful FreeBSD. Not systemd based.

And how are you starting it (display manager or startx)?

I think it's started with this script:

$ cat .xsession
export LIBGL_DRI3_DISABLE=1
source /usr/local/etc/xdg/xfce4/xinitrc

dbus address on systemd changed a while back to use /run/user, but you need to run dbus-update-activation-environment during login.

The OS isn't systemd-based, but there also hasn't been a FreeBSD system update in awhile. The breakage did coincide with a large packages update on April 8th. That's the first time the job failed to suspend the system, and I found a stack of pop-ups with error messages.

Did you try changing your cron to reference this dbus session bus address?

Will try that tonight and let you know how it goes. Thanks again.

UT_qx13s

Member

Registered: 2023-05-04

Posts: 7

Re: [SOLVED] Log-out From Cron Stopped Working

Did you try changing your cron to reference this dbus session bus address?

Okay, this worked. However, whenever I reboot the system, that address will change again. I currently have the cron job configure like so:

$ crontab -l | awk '/sus|sess/'
xfce4_session_logout=/home/UT_qx13s/.bin/xfce4-session-logout.cron
# suspend system after periodic scripts run iff session is locked
*/5 6 1    * *      -n pgrep -q xlock && $xfce4_session_logout
*/5 5 2-31 * 6      -n pgrep -q xlock && $xfce4_session_logout
*/5 4 2-31 * 1-5,7  -n pgrep -q xlock && $xfce4_session_logout

And,

$ !cat
cat .bin/xfce4-session-logout.cron 
#!/bin/sh

export DBUS_SESSION_BUS_ADDRESS=unix:path=/tmp/dbus-nwBNA8LmLz
export DISPLAY=:0.0
/usr/local/bin/xfce4-session-logout --suspend

Is there no automatic way to set that address anymore? Somehow it was being exported to the crontab prior to the package update, but now apparently doesn't.

ToZ

Administrator

From: Canada

Registered: 2011-06-02

Posts: 11,485

Re: [SOLVED] Log-out From Cron Stopped Working

However, whenever I reboot the system, that address will change again.

How about using procstat to pull out the current value. Something like:

procstat -e $(pgrep xfce4-session) | sed 's/ /\n/g' | grep DBUS

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UT_qx13s

Member

Registered: 2023-05-04

Posts: 7

Re: [SOLVED] Log-out From Cron Stopped Working

How about using procstat to pull out the current value.

That works. Thank you for your help.

$ procstat -e $(pgrep xfce4-session) | sed -nr 's/.*(DBUS[^,]*).*/\1/p'
DBUS_SESSION_BUS_ADDRESS=unix:path=/tmp/dbus-nwBNA8LmLz

Last edited by UT_qx13s (2023-05-07 00:41:23)