Fix exception handling for functions_create and data_create

- Change from 'except Exception' to bare 'except' to catch Java
  exceptions from Ghidra that don't inherit from Python Exception
- Use sys.exc_info() to safely extract error messages when str(e)
  might fail on certain Java exception types
- Add null checks after getAddress() since it can return None
  instead of throwing for invalid addresses
- Add last-resort response handling to prevent silent connection
  drops when exception handling itself fails

These endpoints now return proper JSON error responses instead of
causing "Empty reply from server" errors.

docker/MCGhidraServer.py

@@ -412,12 +412,28 @@ class MCGhidraHandler(HttpHandler):
                 "success": False,
                 "error": {"code": "NOT_FOUND", "message": "Endpoint not found: %s %s" % (method, path)}
             })
-        except Exception as e:
+        except:
+            # Catch ALL exceptions including Java exceptions
+            import sys
+            exc_info = sys.exc_info()
+            try:
+                # Try to get a string representation safely
+                if exc_info[1] is not None:
+                    msg = str(exc_info[1])
+                else:
+                    msg = str(exc_info[0])
+            except:
+                msg = "Unknown exception"
             try:
                 self._send_response(exchange, 500, {
                     "success": False,
-                    "error": {"code": "INTERNAL_ERROR", "message": str(e)}
+                    "error": {"code": "INTERNAL_ERROR", "message": msg}
                 })
+            except:
+                # Last resort - at least don't crash silently
+                try:
+                    exchange.sendResponseHeaders(500, 0)
+                    exchange.getResponseBody().close()
                 except:
                     pass
 
@@ -992,6 +1008,9 @@ class MCGhidraHandler(HttpHandler):
         except:
             return {"success": False, "error": {"code": "INVALID_ADDRESS", "message": "Invalid address: %s" % addr_str}}
 
+        if addr is None:
+            return {"success": False, "error": {"code": "INVALID_ADDRESS", "message": "Could not parse address: %s" % addr_str}}
+
         result_holder = [None]
 
         def do_create():
@@ -1009,8 +1028,14 @@ class MCGhidraHandler(HttpHandler):
                     "message": "Function created successfully",
                 }}, 201)
             return {"success": False, "error": {"code": "CREATE_FAILED", "message": "Failed to create function at %s" % addr_str}}
-        except Exception as e:
-            return {"success": False, "error": {"code": "CREATE_ERROR", "message": str(e)}}
+        except:
+            import sys
+            exc = sys.exc_info()[1]
+            try:
+                msg = str(exc)
+            except:
+                msg = "Failed to create function"
+            return {"success": False, "error": {"code": "CREATE_ERROR", "message": msg}}
 
     # -- Signature --
 
@@ -1156,6 +1181,9 @@ class MCGhidraHandler(HttpHandler):
         except:
             return {"success": False, "error": {"code": "INVALID_ADDRESS", "message": "Invalid address: %s" % addr_str}}
 
+        if addr is None:
+            return {"success": False, "error": {"code": "INVALID_ADDRESS", "message": "Could not parse address: %s" % addr_str}}
+
         # Label creation (newName field)
         new_name = body.get("newName")
         if new_name:
@@ -1164,8 +1192,14 @@ class MCGhidraHandler(HttpHandler):
             try:
                 with_transaction(self.program, "Create label", do_label)
                 return {"success": True, "result": {"address": addr_str, "name": new_name, "message": "Label created"}}
-            except Exception as e:
-                return {"success": False, "error": {"code": "LABEL_ERROR", "message": str(e)}}
+            except:
+                import sys
+                exc = sys.exc_info()[1]
+                try:
+                    msg = str(exc)
+                except:
+                    msg = "Failed to create label"
+                return {"success": False, "error": {"code": "LABEL_ERROR", "message": msg}}
 
         # Data creation (type field)
         type_name = body.get("type")
@@ -1187,8 +1221,14 @@ class MCGhidraHandler(HttpHandler):
         try:
             with_transaction(self.program, "Create data", do_create_data)
             return ({"success": True, "result": {"address": addr_str, "type": type_name, "message": "Data created"}}, 201)
-        except Exception as e:
-            return {"success": False, "error": {"code": "DATA_ERROR", "message": str(e)}}
+        except:
+            import sys
+            exc = sys.exc_info()[1]
+            try:
+                msg = str(exc)
+            except:
+                msg = "Failed to create data"
+            return {"success": False, "error": {"code": "DATA_ERROR", "message": msg}}
 
     def handle_data_delete(self, exchange):
         if not self.program: