[systemd-devel] How soon after login can I rely on systemd --user having reached sockets.target?

[Colin Guthrie]

David Herrmann wrote on 19/10/14 12:05:
> Hi
> 
> On Fri, Oct 17, 2014 at 6:14 PM, Colin Guthrie <gmane at colin.guthr.ie> wrote:
>> Hi,
>>
>> How soon after login can I rely on systemd --user having reached
>> sockets.target?
>>
>> This feels a bit like a "you shouldn't rely on that point in time..."
>> type answer is warrented, and when e.g. GNOME or KDE sessions fully use
>> systemd to bring themselves up it won't be an issue, but right now,
>> systemd --user is started by (I think) PAM.
>>
>> I want to rely on systemd --user to handle PulseAudio's activation
>> (ditching the built in stuff) and but I'm worried that e.g. GNOME or KDE
>> might start up their own session stuff and spawn some PA consuming
>> process before systemd --user has reached it's sockets.target and is
>> thus ready and listening on PA's native socket.
>>
>> Doesn't seem to be a problem on my machine here (it's working really
>> nicely actually!) but figured I should ask here too.
> 
> Ordering of user units is (see /usr/lib/systemd/user/):
> default.target after basic.target after sockets.target
> 
> PAM creates sessions by calling into systemd's pam-module, which then
> uses CreateSession() (internal api!). This call does not return until
> the job of user at .service is done. `systemd --user` notifies READY=1
> only after "default.target" is ready.
> 
> Long story short: The PAM module blocks until the user-manager is
> ready. Therefore, sockets.target is loaded and ready.
> 
> (I'm no expert in sd job handling, so maybe Lennart can confirm this)

Thanks for the clarification.

This is pretty much what Lennart thought when I quizzed him a couple
nights ago, but said he'd double check.

It sound like this is indeed the case. Nice :)

Col

-- 

Colin Guthrie
gmane(at)colin.guthr.ie
http://colin.guthr.ie/

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