Close on reconnect

[matt335672]

Fixes #3543
Fixes #1188
Helps with #2765

The draft PR builds on #3547. It uses a new link between sesexec and xrdp to allow sesexec to request xrdp to exit if another client wishes to connect to the same session.

So, if I start a session with:-

xfreerdp /v:<host> /u:<user> /p:<password> /tune:FreeRDP_SupportErrorInfoPdu:true /drive:C,/tmp

and then connect to the same session from elsewhere with the same command, the first command is terminated with these errors (on FreeRDP version 3.16.0):-

[19:54:02:528] [16973:0000424f] [INFO][com.freerdp.core] - [rdp_print_errinfo]: ERRINFO_DISCONNECTED_BY_OTHER_CONNECTION (0x00000005):Another user connected to the server, forcing the disconnection of the current connection.
[19:54:02:529] [16973:0000424f] [ERROR][com.freerdp.core] - [rdp_set_error_info]: ERRINFO_DISCONNECTED_BY_OTHER_CONNECTION [0x00010005]
[19:54:02:529] [16973:0000424f] [ERROR][com.freerdp.core.rdp] - [rdp_recv_callback_int][0x6404001dc8c0]: CONNECTION_STATE_CAPABILITIES_EXCHANGE_DEMAND_ACTIVE status STATE_RUN_QUIT_SESSION [-2]
[19:54:02:529] [16973:0000424f] [ERROR][com.freerdp.core.transport] - [transport_check_fds]: transport_check_fds: transport->ReceiveCallback() - STATE_RUN_QUIT_SESSION [-2]
[19:54:02:531] [16973:00004287] [WARN][com.freerdp.channels.drdynvc.client] - [check_open_close_receive]: {Microsoft::Windows::RDS::DisplayControl:2} OnOpen=(nil), OnClose=0x733a5bca83eb

The session which is now connected can reconnect to chansrv and so copy-paste and drive redirections work as expected.

I've kept this draft for now, as I'm still testing, and also:-

1. I want to get some info regarding the connection available in the xrdp-sesadmin output
2. I need to document the new messages

When this is done, I'm likely to merge #3547, followed by this one.

[matt335672]

Although more testing is required, this PR is now feature complete.

With a connected session:-

$ xrdp-sesadmin -c=list
Session ID: 3397
	Display: :11
	User: testuser
	Session type: Xorg
	Screen size: 1280x1024, color depth 24
	Started: Fri Jul 18 11:41:37 2025
	Start IP address: <snipped>
	Connection state: connected
	Connected client IP: <snipped>
	Connected client name: andelain
	Connection start time: Fri Jul 18 11:42:30 2025

when the session disconnects:-

$ xrdp-sesadmin -c=list
Session ID: 3397
	Display: :11
	User: testuser
	Session type: Xorg
	Screen size: 1280x1024, color depth 24
	Started: Fri Jul 18 11:41:37 2025
	Start IP address: <snipped>
	Connection state: disconnected
	Connection end time: Fri Jul 18 11:52:01 2025

Also, with this in /etc/xrdp/reconnect.sh:-

#!/bin/sh

# Write procedures here you want to execute on reconnect
env | sort >/run/user/$(id -u)/reconnect.log

I get the following variables in the reconnect.log:-

XRDP_CLIENT_IP=<snipped>
XRDP_CLIENT_NAME=andelain

There's clearly more that can be done in terms of improving the xrdp-sesadmin interface, but I'm not planning on doing that as part of this PR - there's plenty enough in here for the time being.

[matt335672]

The wiki is now updated with development and release wiki pages. The development pages describe the new interactions indroduced by this PR and #3547