GDM provides a unix domain socket for communication at
/tmp/.gdm_socket.  Using this you can check if
GDM is running, the version of the daemon, the current servers that are
running and who is logged in on them, and if GDM supports it on your
operating system, also the virtual terminals of all the console logins.
You can also request new flexible servers to be run with this protocol,
but this is best done with the
gdmflexiserver command.
gdmflexiserver accepts the following commands with the --command
option:
VERSION
AUTH_LOCAL
FLEXI_XSERVER
FLEXI_XNEST
ATTACHED_SERVERS
ALL_SERVERS
GET_CONFIG
GET_CONFIG_FILE
UPDATE_CONFIG
GREETERPIDS
QUERY_LOGOUT_ACTION
SET_LOGOUT_ACTION
SET_SAFE_LOGOUT_ACTION
QUERY_VT
SET_VT
CLOSE
These are described in detail below, including required arguments,
response format, and return codes.
