Any reliable way to find the X11 display id and authority file for local session running in actual monitor.

[Michal Srb]

Hi,

I would say a systematic way to do it is using the systemd/logind dbus api.

You can see the information using the command line tool:

# loginctl show-seat seat0
Id=seat0
ActiveSession=1              <- interesting
CanMultiSession=yes
CanTTY=yes
CanGraphical=yes
Sessions=1564 1
IdleHint=no
IdleSinceHint=0
IdleSinceHintMonotonic=0

# loginctl show-session 1
Id=1
User=1000
Name=michal
Timestamp=Mon 2017-07-24 08:42:22 CEST
TimestampMonotonic=42458199
VTNr=7
Seat=seat0
Display=:0               <- interesting
Remote=no
Service=xdm-np
Scope=session-1.scope
Leader=3132              <- interesting
Audit=1
Type=x11
Class=user
Active=yes
State=active
IdleHint=no
IdleSinceHint=0
IdleSinceHintMonotonic=0


No idea about reliable way to find the authority file. Parsing the X's command 
line would probably work in most cases.

Michal Srb