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

[Stef Bon]

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