utils: add method for retrieving unix socket peercred

Signed-off-by:  Eric Callahan <arksine.code@gmail.com>

moonraker/klippy_connection.py

@@ -12,10 +12,8 @@ import logging
 import json
 import getpass
 import asyncio
-import socket
-import struct
 import pathlib
-from utils import ServerError
+from utils import ServerError, get_unix_peer_credentials
 
 # Annotation imports
 from typing import (
@@ -37,7 +35,6 @@ if TYPE_CHECKING:
     from components.klippy_apis import KlippyAPI
     from components.file_manager.file_manager import FileManager
     from components.machine import Machine
-    from asyncio.trsock import TransportSocket
     FlexCallback = Callable[..., Optional[Coroutine]]
 
 INIT_TIME = .25
@@ -258,30 +255,9 @@ class KlippyConnection:
             return await self._init_klippy_connection()
 
     def _get_peer_credentials(self, writer: asyncio.StreamWriter) -> bool:
-        sock: TransportSocket
+        self._peer_cred = get_unix_peer_credentials(writer, "Klippy")
-        sock = writer.get_extra_info("socket", None)
+        if not self._peer_cred:
-        if sock is None:
-            logging.debug(
-                "Unable to get Unix Socket, cant fetch peer credentials"
-            )
             return False
-        data: bytes = b""
-        try:
-            size = struct.calcsize("3I")
-            data = sock.getsockopt(socket.SOL_SOCKET, socket.SO_PEERCRED, size)
-            pid, uid, gid = struct.unpack("3I", data)
-        except asyncio.CancelledError:
-            raise
-        except Exception:
-            logging.exception(
-                f"Failed to get Klippy Peer Credentials, raw: 0x{data.hex()}"
-            )
-            return False
-        self._peer_cred = {
-            "process_id": pid,
-            "user_id": uid,
-            "group_id": gid
-        }
         logging.debug(
             f"Klippy Connection: Received Peer Credentials: {self._peer_cred}"
         )

moonraker/utils.py

@@ -18,6 +18,8 @@ import hashlib
 import json
 import shlex
 import re
+import struct
+import socket
 from queue import SimpleQueue as Queue
 
 # Annotation imports
@@ -33,6 +35,7 @@ from typing import (
 
 if TYPE_CHECKING:
     from types import ModuleType
+    from asyncio.trsock import TransportSocket
 
 MOONRAKER_PATH = str(pathlib.Path(__file__).parent.parent.resolve())
 SYS_MOD_PATHS = glob.glob("/usr/lib/python3*/dist-packages")
@@ -230,3 +233,33 @@ def load_system_module(name: str) -> ModuleType:
     else:
         raise ServerError(f"Unable to import module {name}")
     return module
+
+def get_unix_peer_credentials(
+    writer: asyncio.StreamWriter, name: str
+) -> Dict[str, int]:
+    sock: TransportSocket
+    sock = writer.get_extra_info("socket", None)
+    if sock is None:
+        logging.debug(
+            f"Unable to get underlying Unix Socket for {name}, "
+            "cant fetch peer credentials"
+        )
+        return {}
+    data: bytes = b""
+    try:
+        size = struct.calcsize("3I")
+        data = sock.getsockopt(socket.SOL_SOCKET, socket.SO_PEERCRED, size)
+        pid, uid, gid = struct.unpack("3I", data)
+    except asyncio.CancelledError:
+        raise
+    except Exception:
+        logging.exception(
+            f"Failed to get Unix Socket Peer Credentials for {name}"
+            f", raw: 0x{data.hex()}"
+        )
+        return {}
+    return {
+        "process_id": pid,
+        "user_id": uid,
+        "group_id": gid
+    }