Greetings X2Go Devs,

I use X2Go Server on ten Ubuntu linux machines and ran into an issue this morning upgrading them to 4.0.1.18. We use an automated script I wrote which calls apt-get install and grabs its output, and it hung after upgrading x2goserver.

After much digging, I found that it was hanging because stdin and stdout were not being closed by x2gocleansessions, which is started during the postinst script for x2goserver. Looking through bug reports and commits, it looks like there was a bug #441 to fix a similar problem, but this fix looks like it wasn’t correct. Then, commit 336917af0dc087e4540fb3d55eb501d2fa4349be in 4.0.1.15 implemented a more comprehensive fix, but specifically excludes closing stdin and stout. It looks this still includes a lot of debugging code that should be stripped out, but I’m not sure.

My understanding is that x2gocleansessions should run as a daemon and therefore have no stdin or stdout or at least redirect them to and from /dev/null, but I wanted to check to be sure I wasn’t missing something obvious before I submitted this as a bug. I have briefly tested commenting out the two exclusion lines, causing stdin and stdout to be closed, and it seems to work fine.

I’m not currently subscribed to x2go-dev, so please cc me directly on any response.

Thanks for all your excellent work on X2Go and I look forward to hearing back from someone.

-- Matthew L. Dailey Senior Systems Engineer Thayer School of Engineering Dartmouth College matthew.l.dailey@dartmouth.edu