[systemd-devel] Howto detect a session start (and end) with systemd?

[Stef Bon]

Ok,

forget last message. I've found test-login.c, which gives all answers.

Stef

2012/6/30 Stef Bon <stefbon at gmail.com>:
> Yes,
>
> thank you. It looks like a can use that. It just provides what I need.
>
> The monitor sd_login_monitor can provide a fd. What happens with this
> fd? Is there data readable?
>
> Stef
>
> 2012/6/27 David Herrmann <dh.herrmann at googlemail.com>:
>> Hi Stef
>>
>> On Mon, Jun 25, 2012 at 11:27 AM, Stef Bon <stefbon at gmail.com> wrote:
>>> Hi,
>>>
>>> I'm working on a construction which creates "workspaces" for a user
>>> when he/she logs in.
>>>
>>> These workspaces are directories with vritual directories managed by a
>>> FUSE fs, with access to mountable resources like harddisks, usb
>>> sticks, cdroms but also network services like smb shares.
>>>
>>> In practice this will mean for example the creation of the maps
>>>
>>> Devices
>>>
>>> and
>>>
>>> Network
>>>
>>> in the homedir of the user, and access to local block devices is able
>>> when accessing Devices, and a browseable network map is created in
>>> Network. The first type of workspace works, but still in alpha, more
>>> testing is required, and currently working on the network map enabling
>>> the detection of smb workgroups, servers and shares on the fly.
>>>
>>> Mounting is done by the automounter, using for example mount.cifs for
>>> the smb shares, and contents is redirected to the location where the
>>> resource is available in the workspace by the FUSE fs.
>>>
>>> This construction does not depend on any gui or desktop environment,
>>> like KDE or Gnome, and works on filesystem level. Anyone - also when
>>> loging in from text console - can use this.
>>>
>>> Now this works already very good. I've one program (fuse-workspace)
>>> which watches the sessions starts and ends. I've made this work by
>>> adding the pam module pam_script to the relevant pam files, and make
>>> that module run scripts which maintain a usersessions file.
>>> Fuse-workspace watches that file for changes.
>>> This works, and I'm keeping this for a "always working fallback", but
>>> I would like to know how to do this with systemd, since this is doing
>>> that also, and doing things double is never a good thing on systems
>>> with systemd installed.
>>>
>>> For example: is watching the directory /run/systemd/sessions by
>>> inotify a good idea? (inotify is already used).
>>
>> You can use the sd-login library. It does basically the same as you
>> suggested. It watches the right directories for changes and notifies
>> you. However, it also has some handy helpers to list all sessions so
>> you can refresh your session-list every time the directory changes.
>> See sd-login.h for more information.
>>
>> Regards
>> David