User sessions

[13hakta]

Sometimes when I reconnect to vtm labels like [1000:1] appears on screens.
Please describe how to manage sessions and what this label with session id means?

[o-sdn-o]

There is no global session management yet. Each user manages his session himself -- he can end his session with the Disconnect button. Also, each user can shut down all other sessions by pressing the Shutdown button - this will kick all users from the server and shut it down.

[1000:1] is a combination of two values

• [1000: - user ID issued by the operating system -- for example, in Linux for a regular user, the OS issues 1000, MacOS issues 500, Windows issues a login name string.
• :1] is just the incremental number of the user connected to the server. This number simply increases by one each time the user connects, and never decreases.

[o-sdn-o]

In vtm, sessions are grouped using the user ID issued by the OS (e.g. 1000). In other words, one vtm-server instance for one user ID. For different identifiers, individual servers are launched, and they do not overlap in any way.

[o-sdn-o]

vtm-server gets the ID of the connecting user by making a request to the operating system -- who connected to the pipe that the server is listening to and the operating system reply with such ID.

[o-sdn-o]

The following system calls are used to obtain the credentials of the connected client:

• Linux: getsockopt(handle, SOL_SOCKET, SO_PEERCRED, &cred, &size)
• MacOS (BSD-like): getpeereid(handle, &euid, &egid)
• Windows: Named Pipes - default ACL used for a named pipe grant full control to the LocalSystem, admins, and the creator owner - so no credentials needed.