Doubts about dbus interface

[Iñigo Martínez <martinez i ikusi com>]

Hello:

I have started working in a project where I need some control of the
screen saver. As gnome-screensaver has a dbus interface it looks a good
option, but I'm having some problems/doubts. I'm using gnome 2.30.0.

I was thinking on using SetActive to enable/disable the ScreenSaver. Its
signature is:

> SetActive
> Request a change in the state of the screensaver. Set to TRUE to
> request that the screensaver activate. Active means that the
> screensaver has blanked the screen and may run a graphical theme. This
> does not necessary mean that the screen is locked.
> 
>        Direction
>          Type
>       Description
> in
> boolean
> TRUE to request
> activation, FALSE to
> request deactivation

In my case, in both cases, either passing TRUE or FALSE, it always
produces an activation. May I suppose that it isn't correct ?

Actually I'm using SimulateUserActivity to produce a deactivation. In
this case I have another problem, related to the second doubt.

When I poke the screen saver with SimulateUserActivity if it has been
locked I can't disable it. I saw in the dbus API that there is a
possibility to Lock the screen but not to Unlock it.

I have been thinking about security risk of the possibility of the
screen being unlocked by the screen saver:

  - if the screen saver has the "power" of locking the screen, why not
unlock it ?
  - the goal of the screen saver lock option is to protect
physical/remote access to enter the session of the active user, but
there shouldn't be any problem with programs executed by the user (or
user session) to unlock it.
  - there could be an option to schedule an unlocking of the screen in a
given time.

What do you think ?

Thank you,

Regards,