[Pkg-systemd-maintainers] Bug#745621: modemmanager: pre-removal script fails (with systemd)

[Michael Biebl]

Am 23.04.2014 14:37, schrieb Ansgar Burchardt:
> Package: modemmanager
> Version: 1.0.0-4
> Severity: important
> 
> Removing modemmanager from my desktop system at work fails:
> 
> +---
> | # apt-get purge modemmanager
> | Reading package lists... Done
> | Building dependency tree       
> | Reading state information... Done
> | The following packages will be REMOVED:
> |   modemmanager*
> | 0 upgraded, 0 newly installed, 1 to remove and 18 not upgraded.
> | After this operation, 2191 kB disk space will be freed.
> | Do you want to continue? [Y/n] 
> | (Reading database ... 333498 files and directories currently installed.)
> | Removing modemmanager (1.0.0-4) ...
> | Job for ModemManager.service canceled.
> | dpkg: error processing package modemmanager (--purge):
> |  subprocess installed pre-removal script returned error exit status 1
> | Errors were encountered while processing:
> |  modemmanager
> | E: Sub-process /usr/bin/dpkg returned an error code (1)
> +---

ModemManager is a D-Bus activated service.
I guess there was an incoming D-Bus request when "deb-systemd-invoke
stop" tried to stop the service in prerm, so this request was cancelled.

For socket activated services, we can stop the .socket unit in such a
case [0] to avoid being started by an incoming request. For D-Bus
activated services there is no such equivalent.

So I don't see a good way to fix this. We'd need some kind of "manual"
state a service can be put in during package
installation/upgrade/removal time, i.e. it would need support from
systemd. I'm not sure if blacklisting the service in prerm would help
here. I vaguely remember discussing that a while ago and blacklisting
had some unwanted side-effects.

This might be a good topic for the sprint this weekend, I think, since
we have quite a few D-Bus activated services.


Michael

[0]
http://anonscm.debian.org/gitweb/?p=collab-maint/rsyslog.git;a=blob;f=debian/rsyslog.prerm;hb=HEAD#l6
-- 
Why is it that all of the instruments seeking intelligent life in the
universe are pointed away from Earth?

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