[PATCH weston] introduces a setting to give permission to any client to do screenshots

[Bill Spitzak]

Giulio Camuffo wrote:
> 2013/12/16 Bill Spitzak <spitzak at gmail.com>:
>> Could an api be added so that one client can "give" access to an object to
>> another client? This would allow a single secure client to implement all the
>> rules for what is allowed to be a screen saver, rather than having the rules
>> be in the compositor.
> 
> Yeah, it's possible. See http://git.io/Inq5zA and http://git.io/T0TEdg

I'm not sure what that is doing but it seems to be a communication 
between the server and client, not between two clients.

>> I also think this api would be useful so that a parent client can create a
>> subsurface and then pass it to a child executable to draw into. This appears
>> a lot simpler than the proposed mechanism where the child creates the
>> subsurface.
> 
> I don't see how they relate. That would require sending an object to
> another client.

No, I meant between two clients in both cases.

For the screen shooter, I saw the compositor giving access to the screen 
shooter object to a single trusted client #1, then this client figures 
out that another client #2 is allowed to be a screen shooter and can 
give the screen shooter object to it. Ie it is moved from client 1 to 
client 2. This is done by client 1 sending client 2 the "key" which 
allows client 2 to get an id from the server that it can send messages 
to for that object.

For the subsurface, client 1 creates the subsurface. It then execs 
client 2 and gives it the object so that client 2 can draw into it.