Use posix_ipc to manage shared memory

frigate/util/image.py

@@ -3,15 +3,13 @@
 import datetime
 import logging
 import subprocess as sp
-import threading
 from abc import ABC, abstractmethod
-from multiprocessing import resource_tracker as _mprt
-from multiprocessing import shared_memory as _mpshm
 from string import printable
 from typing import AnyStr, Optional
 
 import cv2
 import numpy as np
+import posix_ipc
 from unidecode import unidecode
 
 logger = logging.getLogger(__name__)
@@ -733,48 +731,26 @@ class FrameManager(ABC):
         pass
 
 
-class UntrackedSharedMemory(_mpshm.SharedMemory):
+class UntrackedSharedMemory:
-    # https://github.com/python/cpython/issues/82300#issuecomment-2169035092
-
-    __lock = threading.Lock()
-
     def __init__(
         self,
         name: Optional[str] = None,
         create: bool = False,
+        unlink: bool = False,
         size: int = 0,
-        *,
-        track: bool = False,
     ) -> None:
-        self._track = track
+        if unlink:
+            return
 
-        # if tracking, normal init will suffice
+        flag = posix_ipc.O_CREAT if create else 0
-        if track:
+        self.shm_store = posix_ipc.SharedMemory(name, flags=flag, size=size)
-            return super().__init__(name=name, create=create, size=size)
 
-        # lock so that other threads don't attempt to use the
+    def close(self) -> None:
-        # register function during this time
+        self.shm_store.fd_close()
-        with self.__lock:
-            # temporarily disable registration during initialization
-            orig_register = _mprt.register
-            _mprt.register = self.__tmp_register
 
-            # initialize; ensure original register function is
+    def unlink(self, name: str) -> None:
-            # re-instated
+        shm = posix_ipc.SharedMemory(name, flags=posix_ipc.O_TRUNC, size=0)
-            try:
+        shm.unlink()
-                super().__init__(name=name, create=create, size=size)
-            finally:
-                _mprt.register = orig_register
-
-    @staticmethod
-    def __tmp_register(*args, **kwargs) -> None:
-        return
-
-    def unlink(self) -> None:
-        if _mpshm._USE_POSIX and self._name:
-            _mpshm._posixshmem.shm_unlink(self._name)
-            if self._track:
-                _mprt.unregister(self._name, "shared_memory")
 
 
 class SharedMemoryFrameManager(FrameManager):
@@ -811,14 +787,14 @@ class SharedMemoryFrameManager(FrameManager):
             self.shm_store[name].close()
 
             try:
-                self.shm_store[name].unlink()
+                self.shm_store[name].unlink(name)
             except FileNotFoundError:
                 pass
 
             del self.shm_store[name]
         else:
             try:
-                shm = UntrackedSharedMemory(name=name)
+                shm = UntrackedSharedMemory(name=name, unlink=True)
                 shm.close()
                 shm.unlink()
             except FileNotFoundError: