bpo-36888: Add multiprocessing.parent_process() (GH-13247)

1 files changed, 9 insertions, 10 deletions

diff --git a/Lib/multiprocessing/spawn.py b/Lib/multiprocessing/spawn.py
index f66b5aa..7cc129e 100644
--- a/Lib/multiprocessing/spawn.py
+++ b/Lib/multiprocessing/spawn.py
@@ -100,25 +100,24 @@ def spawn_main(pipe_handle, parent_pid=None, tracker_fd=None):
 
         if parent_pid is not None:
             source_process = _winapi.OpenProcess(
-                _winapi.PROCESS_DUP_HANDLE, False, parent_pid)
+                _winapi.SYNCHRONIZE | _winapi.PROCESS_DUP_HANDLE,
+                False, parent_pid)
         else:
             source_process = None
-        try:
-            new_handle = reduction.duplicate(pipe_handle,
-                                             source_process=source_process)
-        finally:
-            if source_process is not None:
-                _winapi.CloseHandle(source_process)
+        new_handle = reduction.duplicate(pipe_handle,
+                                         source_process=source_process)
         fd = msvcrt.open_osfhandle(new_handle, os.O_RDONLY)
+        parent_sentinel = source_process
     else:
         from . import resource_tracker
         resource_tracker._resource_tracker._fd = tracker_fd
         fd = pipe_handle
-    exitcode = _main(fd)
+        parent_sentinel = os.dup(pipe_handle)
+    exitcode = _main(fd, parent_sentinel)
     sys.exit(exitcode)
 
 
-def _main(fd):
+def _main(fd, parent_sentinel):
     with os.fdopen(fd, 'rb', closefd=True) as from_parent:
         process.current_process()._inheriting = True
         try:
@@ -127,7 +126,7 @@ def _main(fd):
             self = reduction.pickle.load(from_parent)
         finally:
             del process.current_process()._inheriting
-    return self._bootstrap()
+    return self._bootstrap(parent_sentinel)
 
 
 def _check_not_importing_main():