xrdp doesn't work when started as a service, but works when started manually

Question

Until recently, I had a working xrdp on my CentOS 7.4 workstation. I was able to connect from a Windows machine without any glitches. Then something changed (after a "yum update", maybe?), and I'm now unable to connect (symptom: "vnc error 1 after security negotiation"). I browsed through the logs trying to understand what was happening without much success.

Then, I tried to start xrdp and xrdp-sesman manually (with the -n "no-daemon" flag) on my workstation to get some "live" logs.

Surprisingly (?), when both are started manually I can then reach my machine through xrdp again.

Any idea of the tracks I might explore to fix my problem? You can find zillions of post related to xrdp / vnc / CentOS on the web, most with outdated information, and none were very helpful.

I think that the fact it works when started manually should trigger some flags, for Linux aficionados.

Answer 1

Had exactly the same problem in Debian 9, and found the solution here:

https://github.com/neutrinolabs/xrdp/issues/847

See the comment just over 1/2 way down from imc0. Implementation for me required some modification. All my scripts (startwm.sh - not startwm-bash.sh - and the startwm-local.sh that I created) are in /etc/xrdp/, along with sesman.ini.

Edited in response to comments:

--> in /etc/xrdp create a file named startwm-local.sh which contains:

#!/bin/sh

exec dbus-launch --exit-with-X11 /etc/xrdp/startwm.sh

--> run chmod ugo+x /etc/xrdp/startwm-local.sh

--> edit /etc/xrdp/sesman.ini, and change the lines that read:

UserWindowManager=startwm.sh

DefaultWindowManager=startwm.sh

to:

UserWindowManager=startwm-local.sh

DefaultWindowManager=startwm-local.sh