From bb370c89fe8d36a8fca60405065c3fda07c8659d Mon Sep 17 00:00:00 2001
From: Griatch <griatch@gmail.com>
Date: Sun, 22 Sep 2019 19:22:48 +0200
Subject: [PATCH] Enforce LINEMODE state for vanilla telnet. Resolve #1942

---
 evennia/commands/default/system.py |  4 ++--
 evennia/server/portal/telnet.py    | 26 ++++++++++++++++++--------
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/evennia/commands/default/system.py b/evennia/commands/default/system.py
index 088503df41..fded209d90 100644
--- a/evennia/commands/default/system.py
+++ b/evennia/commands/default/system.py
@@ -298,8 +298,8 @@ class CmdPy(COMMAND_DEFAULT_CLASS):
         being parsed as HTML in the webclient but not in telnet clients)
 
     Without argument, open a Python console in-game. This is a full console,
-    accepting multi-line Python code for testing and debugging. Type `exit` to
-    return to the game. If Evennia is reloaded, thek console will be closed.
+    accepting multi-line Python code for testing and debugging. Type `exit()` to
+    return to the game. If Evennia is reloaded, the console will be closed.
 
     Enter a line of instruction after the 'py' command to execute it
     immediately.  Separate multiple commands by ';' or open the code editor
diff --git a/evennia/server/portal/telnet.py b/evennia/server/portal/telnet.py
index b82754f37a..19ac5d10d8 100644
--- a/evennia/server/portal/telnet.py
+++ b/evennia/server/portal/telnet.py
@@ -11,7 +11,8 @@ import re
 from twisted.internet import protocol
 from twisted.internet.task import LoopingCall
 from twisted.conch.telnet import Telnet, StatefulTelnetProtocol
-from twisted.conch.telnet import IAC, NOP, LINEMODE, GA, WILL, WONT, ECHO, NULL
+from twisted.conch.telnet import (IAC, NOP, LINEMODE, GA, WILL, WONT, ECHO, NULL,
+                                  MODE, LINEMODE_EDIT, LINEMODE_TRAPSIG)
 from django.conf import settings
 from evennia.server.session import Session
 from evennia.server.portal import ttype, mssp, telnet_oob, naws, suppress_ga
@@ -51,6 +52,8 @@ class TelnetProtocol(Telnet, StatefulTelnetProtocol, Session):
         This is called when the connection is first established.
 
         """
+        # important in order to work normally with standard telnet
+        self.do(LINEMODE)
         # initialize the session
         self.line_buffer = b""
         client_address = self.transport.client
@@ -146,12 +149,18 @@ class TelnetProtocol(Telnet, StatefulTelnetProtocol, Session):
             enable (bool): If this option should be enabled.
 
         """
-        return (option == LINEMODE or
-                option == ttype.TTYPE or
-                option == naws.NAWS or
-                option == MCCP or
-                option == mssp.MSSP or
-                option == suppress_ga.SUPPRESS_GA)
+        if option == LINEMODE:
+            # make sure to activate line mode with local editing for all clients
+            self.requestNegotiation(LINEMODE, MODE +
+                                    bytes(chr(ord(LINEMODE_EDIT) +
+                                              ord(LINEMODE_TRAPSIG)), 'ascii'))
+            return True
+        else:
+            return (option == ttype.TTYPE or
+                    option == naws.NAWS or
+                    option == MCCP or
+                    option == mssp.MSSP or
+                    option == suppress_ga.SUPPRESS_GA)
 
     def enableLocal(self, option):
         """
@@ -164,7 +173,8 @@ class TelnetProtocol(Telnet, StatefulTelnetProtocol, Session):
             enable (bool): If this option should be enabled.
 
         """
-        return (option == MCCP or
+        return (option == LINEMODE or
+                option == MCCP or
                 option == ECHO or
                 option == suppress_ga.SUPPRESS_GA)