stracing login process with systemd?

[Eduard Bloch <edi@gmx.de>]

Dear Lazynet,

I have some trouble with one desktop system running Sid. After some
updates a couple of weeks ago, user programs started to fail, like
pulseaudio no longer running or "systemctl suspend" not working.

After little investigation I have found out that "systemd --user"
process is not working which is supposed to run user-specific services.

Which is probably somethign that libpam-systemd should have invoked -
that was the best guess I could extract from the documentation (the
manpage of systemd is AFAICS NOT telling you who/what is supposed to
start the user systemd).

I had some exchange with the maintainer in the BTS but so far that's not
really fruitful. I would like to just strace the whole login process
(console or xdm) and check what's happening there around systemd
invocation, and what's failing.

Does anyone know how to insert strace or any similar tracing utility?

I can imagine that one could try to use kernel tracing here but that
would be a huge hammer.

Thanks,
Eduard.

-- 
Every great idea is worthless without someone to do the work. --Neil Williams