From 883977069a1faae14f1bbfb7ec59bb0c65491cb0 Mon Sep 17 00:00:00 2001
From: tomMoral <thomas.moreau.2010@gmail.com>
Date: Fri, 10 May 2019 22:32:27 +0200
Subject: [PATCH 01/25] ENH add parent_process in multiprocessing contexts

---
 Lib/multiprocessing/popen_fork.py |  2 +-
 Lib/multiprocessing/process.py    | 36 ++++++++++++++++++++++++++++---
 Lib/multiprocessing/spawn.py      |  4 ++--
 3 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/Lib/multiprocessing/popen_fork.py b/Lib/multiprocessing/popen_fork.py
index 685e8daf77ca1f..ac8dc58e944e50 100644
--- a/Lib/multiprocessing/popen_fork.py
+++ b/Lib/multiprocessing/popen_fork.py
@@ -70,7 +70,7 @@ def _launch(self, process_obj):
         if self.pid == 0:
             try:
                 os.close(parent_r)
-                code = process_obj._bootstrap()
+                code = process_obj._bootstrap(parent_sentinel=child_w)
             finally:
                 os._exit(code)
         else:
diff --git a/Lib/multiprocessing/process.py b/Lib/multiprocessing/process.py
index 780f2d0c273472..e7a4d97d9ca140 100644
--- a/Lib/multiprocessing/process.py
+++ b/Lib/multiprocessing/process.py
@@ -7,7 +7,8 @@
 # Licensed to PSF under a Contributor Agreement.
 #
 
-__all__ = ['BaseProcess', 'current_process', 'active_children']
+__all__ = ['BaseProcess', 'current_process', 'active_children',
+           'parent_process']
 
 #
 # Imports
@@ -46,6 +47,13 @@ def active_children():
     _cleanup()
     return list(_children)
 
+
+def parent_process():
+    '''
+    Return process object representing the parent process
+    '''
+    return _parent_process
+
 #
 #
 #
@@ -278,9 +286,9 @@ def __repr__(self):
 
     ##
 
-    def _bootstrap(self):
+    def _bootstrap(self, parent_sentinel=None):
         from . import util, context
-        global _current_process, _process_counter, _children
+        global _current_process, _parent_process, _process_counter, _children
 
         try:
             if self._start_method is not None:
@@ -289,6 +297,8 @@ def _bootstrap(self):
             _children = set()
             util._close_stdin()
             old_process = _current_process
+            _parent_process = _ParentProcess(old_process.name, old_process.pid,
+                                             parent_sentinel)
             _current_process = self
             try:
                 util._finalizer_registry.clear()
@@ -337,6 +347,25 @@ def __reduce__(self):
                 )
         return AuthenticationString, (bytes(self),)
 
+
+#
+# Create object representing the parent process
+#
+
+class _ParentProcess(BaseProcess):
+
+    def __init__(self, name, pid, sentinel):
+        self._identity = ()
+        self._name = name
+        self._parent_pid = pid
+        self._popen = None
+        self._closed = False
+        self._sentinel = sentinel
+
+    def close(self):
+        pass
+
+
 #
 # Create object representing the main process
 #
@@ -365,6 +394,7 @@ def close(self):
         pass
 
 
+_parent_process = None
 _current_process = _MainProcess()
 _process_counter = itertools.count(1)
 _children = set()
diff --git a/Lib/multiprocessing/spawn.py b/Lib/multiprocessing/spawn.py
index f66b5aa9267b6d..06ed2a942f817d 100644
--- a/Lib/multiprocessing/spawn.py
+++ b/Lib/multiprocessing/spawn.py
@@ -119,7 +119,7 @@ def spawn_main(pipe_handle, parent_pid=None, tracker_fd=None):
 
 
 def _main(fd):
-    with os.fdopen(fd, 'rb', closefd=True) as from_parent:
+    with os.fdopen(fd, 'rb', closefd=False) as from_parent:
         process.current_process()._inheriting = True
         try:
             preparation_data = reduction.pickle.load(from_parent)
@@ -127,7 +127,7 @@ def _main(fd):
             self = reduction.pickle.load(from_parent)
         finally:
             del process.current_process()._inheriting
-    return self._bootstrap()
+    return self._bootstrap(parent_sentinel=fd)
 
 
 def _check_not_importing_main():

From bcdba7375e6cb98398e2249bb2f3dcd1fdcc8858 Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Thu, 16 May 2019 14:30:42 +0200
Subject: [PATCH 02/25] FIX avoid error in Process.__repr__

---
 Lib/multiprocessing/process.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Lib/multiprocessing/process.py b/Lib/multiprocessing/process.py
index e7a4d97d9ca140..589addcc4586ca 100644
--- a/Lib/multiprocessing/process.py
+++ b/Lib/multiprocessing/process.py
@@ -361,6 +361,7 @@ def __init__(self, name, pid, sentinel):
         self._popen = None
         self._closed = False
         self._sentinel = sentinel
+        self._config = {}
 
     def close(self):
         pass

From 98de00158885adffd0a2c1e5a01212e2a3c92b55 Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Thu, 16 May 2019 14:35:54 +0200
Subject: [PATCH 03/25] CLN more logical attribute naming

---
 Lib/multiprocessing/process.py | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/Lib/multiprocessing/process.py b/Lib/multiprocessing/process.py
index 589addcc4586ca..1e48ada2662b90 100644
--- a/Lib/multiprocessing/process.py
+++ b/Lib/multiprocessing/process.py
@@ -357,7 +357,8 @@ class _ParentProcess(BaseProcess):
     def __init__(self, name, pid, sentinel):
         self._identity = ()
         self._name = name
-        self._parent_pid = pid
+        self._pid = pid
+        self._parent_pid = None
         self._popen = None
         self._closed = False
         self._sentinel = sentinel
@@ -366,6 +367,11 @@ def __init__(self, name, pid, sentinel):
     def close(self):
         pass
 
+    @property
+    def ident(self):
+        return self._pid
+
+    pid = ident
 
 #
 # Create object representing the main process

From 9b6703496731365cb34390f9f90de0f0c983078f Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Thu, 16 May 2019 14:36:40 +0200
Subject: [PATCH 04/25] ENH implement ParentProcess.is_alive

---
 Lib/multiprocessing/popen_forkserver.py  | 2 +-
 Lib/multiprocessing/popen_spawn_posix.py | 2 +-
 Lib/multiprocessing/process.py           | 4 ++++
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/Lib/multiprocessing/popen_forkserver.py b/Lib/multiprocessing/popen_forkserver.py
index a51a2771aed8cc..a6915b7da5bd81 100644
--- a/Lib/multiprocessing/popen_forkserver.py
+++ b/Lib/multiprocessing/popen_forkserver.py
@@ -50,7 +50,7 @@ def _launch(self, process_obj):
 
         self.sentinel, w = forkserver.connect_to_new_process(self._fds)
         self.finalizer = util.Finalize(self, os.close, (self.sentinel,))
-        with open(w, 'wb', closefd=True) as f:
+        with open(w, 'wb', closefd=False) as f:
             f.write(buf.getbuffer())
         self.pid = forkserver.read_signed(self.sentinel)
 
diff --git a/Lib/multiprocessing/popen_spawn_posix.py b/Lib/multiprocessing/popen_spawn_posix.py
index 59f8e452cae1d5..d8ce4cbe54031c 100644
--- a/Lib/multiprocessing/popen_spawn_posix.py
+++ b/Lib/multiprocessing/popen_spawn_posix.py
@@ -63,6 +63,6 @@ def _launch(self, process_obj):
         finally:
             if parent_r is not None:
                 self.finalizer = util.Finalize(self, os.close, (parent_r,))
-            for fd in (child_r, child_w, parent_w):
+            for fd in (child_r, child_w):
                 if fd is not None:
                     os.close(fd)
diff --git a/Lib/multiprocessing/process.py b/Lib/multiprocessing/process.py
index 1e48ada2662b90..e8a6d39df63418 100644
--- a/Lib/multiprocessing/process.py
+++ b/Lib/multiprocessing/process.py
@@ -367,6 +367,10 @@ def __init__(self, name, pid, sentinel):
     def close(self):
         pass
 
+    def is_alive(self):
+        from multiprocessing.connection import wait
+        return not wait([self._sentinel], timeout=0)
+
     @property
     def ident(self):
         return self._pid

From 23a2f3d1ad65aaf48029927db92ecaa34fba5c3f Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Thu, 16 May 2019 14:39:05 +0200
Subject: [PATCH 05/25] FIX pass parent_name to ParentProcess

---
 Lib/multiprocessing/process.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Lib/multiprocessing/process.py b/Lib/multiprocessing/process.py
index e8a6d39df63418..a975cc7e78a41e 100644
--- a/Lib/multiprocessing/process.py
+++ b/Lib/multiprocessing/process.py
@@ -84,6 +84,7 @@ def __init__(self, group=None, target=None, name=None, args=(), kwargs={},
         self._identity = _current_process._identity + (count,)
         self._config = _current_process._config.copy()
         self._parent_pid = os.getpid()
+        self._parent_name = _current_process.name
         self._popen = None
         self._closed = False
         self._target = target

From 5630de589d4255a00c4fbf65dcedabb53b798471 Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Thu, 16 May 2019 14:39:35 +0200
Subject: [PATCH 06/25] do not use current_process to create ParentProcess

---
 Lib/multiprocessing/process.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Lib/multiprocessing/process.py b/Lib/multiprocessing/process.py
index a975cc7e78a41e..0364ea140abe3f 100644
--- a/Lib/multiprocessing/process.py
+++ b/Lib/multiprocessing/process.py
@@ -298,9 +298,9 @@ def _bootstrap(self, parent_sentinel=None):
             _children = set()
             util._close_stdin()
             old_process = _current_process
-            _parent_process = _ParentProcess(old_process.name, old_process.pid,
-                                             parent_sentinel)
             _current_process = self
+            _parent_process = _ParentProcess(
+                self._parent_name, self._parent_pid, parent_sentinel)
             try:
                 util._finalizer_registry.clear()
                 util._run_after_forkers()

From be73255a72991b23f3f9f10945458bdb4b7e1eee Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Thu, 16 May 2019 14:40:18 +0200
Subject: [PATCH 07/25] TST test parent_process use-cases

---
 Lib/test/_test_multiprocessing.py | 56 +++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py
index 772c9638337ae5..5d117bcd441c02 100644
--- a/Lib/test/_test_multiprocessing.py
+++ b/Lib/test/_test_multiprocessing.py
@@ -269,6 +269,62 @@ def _test(cls, q, *args, **kwds):
             q.put(bytes(current.authkey))
             q.put(current.pid)
 
+    def test_parent_process_attributes(self):
+        if self.TYPE == "threads":
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+        from multiprocessing.process import current_process
+        rconn, wconn = self.Pipe(duplex=False)
+        p = self.Process(target=self._test_send_parent_process, args=(wconn,))
+        p.start()
+        p.join()
+        parent_process = rconn.recv()
+        assert parent_process.pid == current_process().pid
+        assert parent_process.name == current_process().name
+
+    @classmethod
+    def _test_send_parent_process(cls, wconn):
+        from multiprocessing.process import parent_process
+        wconn.send(parent_process())
+
+    def test_parent_process(self):
+        if self.TYPE == "threads":
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        # Launch a child process. Make it launch a grandchild process. Kill the
+        # child process and make sure that the grandchild notices the death of
+        # its parent (a.k.a the child process).
+        rconn, wconn = self.Pipe(duplex=False)
+        p = self.Process(
+            target=self._test_create_grandchild_process, args=(wconn, ))
+        p.start()
+        time.sleep(1)
+        p.terminate()
+        p.join()
+        parent_process_status_log = rconn.recv()
+        assert parent_process_status_log == ["alive", "not alive"]
+
+    @classmethod
+    def _test_create_grandchild_process(cls, wconn):
+        p = cls.Process(target=cls._test_report_parent_status, args=(wconn, ))
+        p.start()
+        time.sleep(100)
+
+    @classmethod
+    def _test_report_parent_status(cls, wconn):
+        from multiprocessing.process import parent_process
+        status_log = []
+        status_log.append(
+            "alive" if parent_process().is_alive() else "not alive")
+
+        start_time = time.monotonic()
+        while (parent_process().is_alive() and
+               (time.monotonic() - start_time) < 5):
+            time.sleep(0.1)
+
+        status_log.append(
+            "alive" if parent_process().is_alive() else "not alive")
+        wconn.send(status_log)
+
     def test_process(self):
         q = self.Queue(1)
         e = self.Event()

From faa3fb8f835ec8b0f2a44a0dd3048dfab127ece0 Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Thu, 16 May 2019 14:51:29 +0200
Subject: [PATCH 08/25] FIX do not close parent_sentinel on windows

---
 Lib/multiprocessing/popen_spawn_win32.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Lib/multiprocessing/popen_spawn_win32.py b/Lib/multiprocessing/popen_spawn_win32.py
index de4c5ecf1fa083..f7e0bdcac3ca3b 100644
--- a/Lib/multiprocessing/popen_spawn_win32.py
+++ b/Lib/multiprocessing/popen_spawn_win32.py
@@ -68,7 +68,7 @@ def __init__(self, process_obj):
         else:
             env = None
 
-        with open(wfd, 'wb', closefd=True) as to_child:
+        with open(wfd, 'wb', closefd=False) as to_child:
             # start process
             try:
                 hp, ht, pid, tid = _winapi.CreateProcess(

From cd2f241a3ca1cefe3c784af62b6d99ebd45ca1d3 Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Thu, 16 May 2019 07:12:59 -0700
Subject: [PATCH 09/25] FIX implement ParentProcess on windows

---
 Lib/multiprocessing/spawn.py | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/Lib/multiprocessing/spawn.py b/Lib/multiprocessing/spawn.py
index 06ed2a942f817d..20fdb008482a2d 100644
--- a/Lib/multiprocessing/spawn.py
+++ b/Lib/multiprocessing/spawn.py
@@ -100,25 +100,22 @@ 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.PROCESS_ALL_ACCESS, 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)
+        fd = parent_sentinel = pipe_handle
+    exitcode = _main(fd, parent_sentinel)
     sys.exit(exitcode)
 
 
-def _main(fd):
+def _main(fd, parent_sentinel):
     with os.fdopen(fd, 'rb', closefd=False) as from_parent:
         process.current_process()._inheriting = True
         try:
@@ -127,7 +124,7 @@ def _main(fd):
             self = reduction.pickle.load(from_parent)
         finally:
             del process.current_process()._inheriting
-    return self._bootstrap(parent_sentinel=fd)
+    return self._bootstrap(parent_sentinel)
 
 
 def _check_not_importing_main():

From 3d71d3f0dce1649aa724c4f94e9c8d53b954a7d4 Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Thu, 16 May 2019 18:02:16 +0200
Subject: [PATCH 10/25] MNT news entry

---
 .../next/Library/2019-05-16-18-02-08.bpo-36888.-H2Dkm.rst       | 2 ++
 1 file changed, 2 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Library/2019-05-16-18-02-08.bpo-36888.-H2Dkm.rst

diff --git a/Misc/NEWS.d/next/Library/2019-05-16-18-02-08.bpo-36888.-H2Dkm.rst b/Misc/NEWS.d/next/Library/2019-05-16-18-02-08.bpo-36888.-H2Dkm.rst
new file mode 100644
index 00000000000000..e7b54677280c9f
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-05-16-18-02-08.bpo-36888.-H2Dkm.rst
@@ -0,0 +1,2 @@
+Python child processes can now access the status of their parent process
+using multiprocessing.process.parent_process

From 0ceffc8bd7a431b5558ed76d6551d9f8dc3616fa Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Thu, 16 May 2019 18:53:56 +0200
Subject: [PATCH 11/25] FIX _main for forkserver

---
 Lib/multiprocessing/forkserver.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Lib/multiprocessing/forkserver.py b/Lib/multiprocessing/forkserver.py
index dabf7bcbe6d785..cdcb24f8d297f1 100644
--- a/Lib/multiprocessing/forkserver.py
+++ b/Lib/multiprocessing/forkserver.py
@@ -294,7 +294,7 @@ def _serve_one(child_r, fds, unused_fds, handlers):
      *_forkserver._inherited_fds) = fds
 
     # Run process object received over pipe
-    code = spawn._main(child_r)
+    code = spawn._main(child_r, child_r)
 
     return code
 

From 9382659078dd55644c9b69103cce25d93479aa51 Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Thu, 16 May 2019 18:55:55 +0200
Subject: [PATCH 12/25] TST better tests

---
 Lib/test/_test_multiprocessing.py | 31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py
index 5d117bcd441c02..f419a1f658979d 100644
--- a/Lib/test/_test_multiprocessing.py
+++ b/Lib/test/_test_multiprocessing.py
@@ -277,14 +277,15 @@ def test_parent_process_attributes(self):
         p = self.Process(target=self._test_send_parent_process, args=(wconn,))
         p.start()
         p.join()
-        parent_process = rconn.recv()
-        assert parent_process.pid == current_process().pid
-        assert parent_process.name == current_process().name
+        parent_pid, parent_name = rconn.recv()
+        self.assertEqual(parent_pid, current_process().pid)
+        self.assertEqual(parent_pid, os.getpid())
+        self.assertEqual(parent_name, current_process().name)
 
     @classmethod
     def _test_send_parent_process(cls, wconn):
         from multiprocessing.process import parent_process
-        wconn.send(parent_process())
+        wconn.send([parent_process().pid, parent_process().name])
 
     def test_parent_process(self):
         if self.TYPE == "threads":
@@ -297,11 +298,19 @@ def test_parent_process(self):
         p = self.Process(
             target=self._test_create_grandchild_process, args=(wconn, ))
         p.start()
-        time.sleep(1)
+
+        if not rconn.poll(timeout=5):
+            raise AssertionError("Could not communicate with child process")
+        parent_process_status = rconn.recv()
+        self.assertEqual(parent_process_status, "alive")
+
         p.terminate()
         p.join()
-        parent_process_status_log = rconn.recv()
-        assert parent_process_status_log == ["alive", "not alive"]
+
+        if not rconn.poll(timeout=5):
+            raise AssertionError("Could not communicate with child process")
+        parent_process_status = rconn.recv()
+        self.assertEqual(parent_process_status, "not alive")
 
     @classmethod
     def _test_create_grandchild_process(cls, wconn):
@@ -312,18 +321,14 @@ def _test_create_grandchild_process(cls, wconn):
     @classmethod
     def _test_report_parent_status(cls, wconn):
         from multiprocessing.process import parent_process
-        status_log = []
-        status_log.append(
-            "alive" if parent_process().is_alive() else "not alive")
+        wconn.send("alive" if parent_process().is_alive() else "not alive")
 
         start_time = time.monotonic()
         while (parent_process().is_alive() and
                (time.monotonic() - start_time) < 5):
             time.sleep(0.1)
 
-        status_log.append(
-            "alive" if parent_process().is_alive() else "not alive")
-        wconn.send(status_log)
+        wconn.send("alive" if parent_process().is_alive() else "not alive")
 
     def test_process(self):
         q = self.Queue(1)

From 95dfc61ff45abc0982938eb3b894dddfbdf98a4e Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Mon, 20 May 2019 01:42:17 -0700
Subject: [PATCH 13/25] ENH use narrower permissions on windows

---
 Lib/multiprocessing/spawn.py | 3 ++-
 Modules/_winapi.c            | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/Lib/multiprocessing/spawn.py b/Lib/multiprocessing/spawn.py
index 20fdb008482a2d..dd0cd45ea0ffd8 100644
--- a/Lib/multiprocessing/spawn.py
+++ b/Lib/multiprocessing/spawn.py
@@ -100,7 +100,8 @@ def spawn_main(pipe_handle, parent_pid=None, tracker_fd=None):
 
         if parent_pid is not None:
             source_process = _winapi.OpenProcess(
-                _winapi.PROCESS_ALL_ACCESS, False, parent_pid)
+                _winapi.SYNCHRONIZE | _winapi.PROCESS_DUP_HANDLE,
+                False, parent_pid)
         else:
             source_process = None
         new_handle = reduction.duplicate(pipe_handle,
diff --git a/Modules/_winapi.c b/Modules/_winapi.c
index 2eb708e9073e91..8873519e6ce5df 100644
--- a/Modules/_winapi.c
+++ b/Modules/_winapi.c
@@ -1955,6 +1955,7 @@ PyInit__winapi(void)
     WINAPI_CONSTANT(F_DWORD, PIPE_UNLIMITED_INSTANCES);
     WINAPI_CONSTANT(F_DWORD, PIPE_WAIT);
     WINAPI_CONSTANT(F_DWORD, PROCESS_ALL_ACCESS);
+    WINAPI_CONSTANT(F_DWORD, SYNCHRONIZE);
     WINAPI_CONSTANT(F_DWORD, PROCESS_DUP_HANDLE);
     WINAPI_CONSTANT(F_DWORD, SEC_COMMIT);
     WINAPI_CONSTANT(F_DWORD, SEC_IMAGE);

From 29898b532d1ee567ffc70b8adbed88eb969a352d Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Mon, 20 May 2019 11:01:13 +0200
Subject: [PATCH 14/25] FIX duplicate sentinel when necessary

---
 Lib/multiprocessing/spawn.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/Lib/multiprocessing/spawn.py b/Lib/multiprocessing/spawn.py
index dd0cd45ea0ffd8..850184a1b95f0d 100644
--- a/Lib/multiprocessing/spawn.py
+++ b/Lib/multiprocessing/spawn.py
@@ -111,13 +111,13 @@ def spawn_main(pipe_handle, parent_pid=None, tracker_fd=None):
     else:
         from . import resource_tracker
         resource_tracker._resource_tracker._fd = tracker_fd
-        fd = parent_sentinel = pipe_handle
-    exitcode = _main(fd, parent_sentinel)
+        parent_sentinel = os.dup(pipe_handle)
+    exitcode = _main(pipe_handle, parent_sentinel)
     sys.exit(exitcode)
 
 
 def _main(fd, parent_sentinel):
-    with os.fdopen(fd, 'rb', closefd=False) as from_parent:
+    with os.fdopen(fd, 'rb', closefd=True) as from_parent:
         process.current_process()._inheriting = True
         try:
             preparation_data = reduction.pickle.load(from_parent)

From 566db0e941c3c80433ac52f996aa310a64264771 Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Mon, 20 May 2019 11:40:51 +0200
Subject: [PATCH 15/25] ENH listen to read end of a pipe in fork

---
 Lib/multiprocessing/popen_fork.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/Lib/multiprocessing/popen_fork.py b/Lib/multiprocessing/popen_fork.py
index ac8dc58e944e50..4ec924e1f23aab 100644
--- a/Lib/multiprocessing/popen_fork.py
+++ b/Lib/multiprocessing/popen_fork.py
@@ -66,15 +66,18 @@ def kill(self):
     def _launch(self, process_obj):
         code = 1
         parent_r, child_w = os.pipe()
+        child_r, parent_w = os.pipe()
         self.pid = os.fork()
         if self.pid == 0:
             try:
                 os.close(parent_r)
-                code = process_obj._bootstrap(parent_sentinel=child_w)
+                os.close(parent_w)
+                code = process_obj._bootstrap(parent_sentinel=child_r)
             finally:
                 os._exit(code)
         else:
             os.close(child_w)
+            os.close(child_r)
             self.finalizer = util.Finalize(self, os.close, (parent_r,))
             self.sentinel = parent_r
 

From a2310a78f8499139065a869509bef3597c2b79cd Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Mon, 20 May 2019 12:23:41 +0200
Subject: [PATCH 16/25] FIX duplicate the parent sentinel in forkserver

---
 Lib/multiprocessing/forkserver.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Lib/multiprocessing/forkserver.py b/Lib/multiprocessing/forkserver.py
index cdcb24f8d297f1..9b6398671dbc5e 100644
--- a/Lib/multiprocessing/forkserver.py
+++ b/Lib/multiprocessing/forkserver.py
@@ -294,7 +294,8 @@ def _serve_one(child_r, fds, unused_fds, handlers):
      *_forkserver._inherited_fds) = fds
 
     # Run process object received over pipe
-    code = spawn._main(child_r, child_r)
+    parent_sentinel = os.dup(child_r)
+    code = spawn._main(child_r, parent_sentinel)
 
     return code
 

From b3829f62ad00447c3023a9ef51d289adb6eb4884 Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Mon, 20 May 2019 12:26:40 +0200
Subject: [PATCH 17/25] ENH access parent_process from multiprocessing

---
 Lib/multiprocessing/context.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Lib/multiprocessing/context.py b/Lib/multiprocessing/context.py
index 871746b1a047b3..5a4865751c2272 100644
--- a/Lib/multiprocessing/context.py
+++ b/Lib/multiprocessing/context.py
@@ -35,6 +35,7 @@ class BaseContext(object):
     AuthenticationError = AuthenticationError
 
     current_process = staticmethod(process.current_process)
+    parent_process = staticmethod(process.parent_process)
     active_children = staticmethod(process.active_children)
 
     def cpu_count(self):

From 133df9c56b948bb684f8729811228493bec52bcc Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Mon, 20 May 2019 12:35:55 +0200
Subject: [PATCH 18/25] TST improve test coverage and readability

---
 Lib/test/_test_multiprocessing.py | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py
index f419a1f658979d..c70c93b2b443b7 100644
--- a/Lib/test/_test_multiprocessing.py
+++ b/Lib/test/_test_multiprocessing.py
@@ -272,15 +272,17 @@ def _test(cls, q, *args, **kwds):
     def test_parent_process_attributes(self):
         if self.TYPE == "threads":
             self.skipTest('test not appropriate for {}'.format(self.TYPE))
-        from multiprocessing.process import current_process
+
+        self.assertIsNone(self.parent_process())
+
         rconn, wconn = self.Pipe(duplex=False)
         p = self.Process(target=self._test_send_parent_process, args=(wconn,))
         p.start()
         p.join()
         parent_pid, parent_name = rconn.recv()
-        self.assertEqual(parent_pid, current_process().pid)
+        self.assertEqual(parent_pid, self.current_process().pid)
         self.assertEqual(parent_pid, os.getpid())
-        self.assertEqual(parent_name, current_process().name)
+        self.assertEqual(parent_name, self.current_process().name)
 
     @classmethod
     def _test_send_parent_process(cls, wconn):
@@ -5451,6 +5453,7 @@ class ProcessesMixin(BaseMixin):
     Process = multiprocessing.Process
     connection = multiprocessing.connection
     current_process = staticmethod(multiprocessing.current_process)
+    parent_process = staticmethod(multiprocessing.parent_process)
     active_children = staticmethod(multiprocessing.active_children)
     Pool = staticmethod(multiprocessing.Pool)
     Pipe = staticmethod(multiprocessing.Pipe)

From 3c5d2418ed874ea2b69a47025767739da1a91f8e Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Mon, 20 May 2019 14:00:05 +0200
Subject: [PATCH 19/25] FIX pass correct fd to spawn on windows

---
 Lib/multiprocessing/spawn.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Lib/multiprocessing/spawn.py b/Lib/multiprocessing/spawn.py
index 850184a1b95f0d..7cc129e2610761 100644
--- a/Lib/multiprocessing/spawn.py
+++ b/Lib/multiprocessing/spawn.py
@@ -111,8 +111,9 @@ def spawn_main(pipe_handle, parent_pid=None, tracker_fd=None):
     else:
         from . import resource_tracker
         resource_tracker._resource_tracker._fd = tracker_fd
+        fd = pipe_handle
         parent_sentinel = os.dup(pipe_handle)
-    exitcode = _main(pipe_handle, parent_sentinel)
+    exitcode = _main(fd, parent_sentinel)
     sys.exit(exitcode)
 
 

From 4fe8467221b0776e3bf29cff4d3ac47a1e73177d Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Mon, 20 May 2019 14:32:30 +0200
Subject: [PATCH 20/25] DOC docs

---
 Doc/library/multiprocessing.rst | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst
index c6ffb00819c32c..cc6dd4e9d70226 100644
--- a/Doc/library/multiprocessing.rst
+++ b/Doc/library/multiprocessing.rst
@@ -944,6 +944,14 @@ Miscellaneous
 
    An analogue of :func:`threading.current_thread`.
 
+.. function:: parent_process()
+
+   Return the :class:`Process` object corresponding to the parent process of
+   the :func:`current_process`. For the main process, ``parent_process`` will
+   be ``None``.
+
+   .. versionadded:: 3.8
+
 .. function:: freeze_support()
 
    Add support for when a program which uses :mod:`multiprocessing` has been

From a9c987ce79b05b2330a54e0b2a84db8e3a3fc66a Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Mon, 20 May 2019 14:41:51 +0200
Subject: [PATCH 21/25] CLN duplicate fd instead of not closing it

---
 Lib/multiprocessing/popen_forkserver.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Lib/multiprocessing/popen_forkserver.py b/Lib/multiprocessing/popen_forkserver.py
index a6915b7da5bd81..aba61a30b47030 100644
--- a/Lib/multiprocessing/popen_forkserver.py
+++ b/Lib/multiprocessing/popen_forkserver.py
@@ -50,7 +50,8 @@ def _launch(self, process_obj):
 
         self.sentinel, w = forkserver.connect_to_new_process(self._fds)
         self.finalizer = util.Finalize(self, os.close, (self.sentinel,))
-        with open(w, 'wb', closefd=False) as f:
+        parent_sentinel = os.dup(w)
+        with open(w, 'wb', closefd=True) as f:
             f.write(buf.getbuffer())
         self.pid = forkserver.read_signed(self.sentinel)
 

From e23cc089c261897cdaff6971ca1216dfc76223d1 Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Mon, 20 May 2019 19:04:26 +0200
Subject: [PATCH 22/25] address review comments

---
 Lib/multiprocessing/popen_fork.py        |  2 ++
 Lib/multiprocessing/popen_forkserver.py  |  5 ++++-
 Lib/multiprocessing/popen_spawn_posix.py |  2 ++
 Lib/multiprocessing/popen_spawn_win32.py |  2 +-
 Lib/multiprocessing/process.py           | 10 +++++++---
 Lib/test/_test_multiprocessing.py        |  4 +---
 6 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/Lib/multiprocessing/popen_fork.py b/Lib/multiprocessing/popen_fork.py
index 4ec924e1f23aab..02551a9d1b4d46 100644
--- a/Lib/multiprocessing/popen_fork.py
+++ b/Lib/multiprocessing/popen_fork.py
@@ -79,7 +79,9 @@ def _launch(self, process_obj):
             os.close(child_w)
             os.close(child_r)
             self.finalizer = util.Finalize(self, os.close, (parent_r,))
+            self.finalizer = util.Finalize(self, os.close, (parent_w,))
             self.sentinel = parent_r
+            self._parent_w = parent_w
 
     def close(self):
         if self.finalizer is not None:
diff --git a/Lib/multiprocessing/popen_forkserver.py b/Lib/multiprocessing/popen_forkserver.py
index aba61a30b47030..c7c45473fa86d1 100644
--- a/Lib/multiprocessing/popen_forkserver.py
+++ b/Lib/multiprocessing/popen_forkserver.py
@@ -49,8 +49,11 @@ def _launch(self, process_obj):
             set_spawning_popen(None)
 
         self.sentinel, w = forkserver.connect_to_new_process(self._fds)
+        # Keep a duplicate of the data pipe's write end as a sentinel of the
+        # parent process used by the child process.
+        self._parent_w = os.dup(w)
         self.finalizer = util.Finalize(self, os.close, (self.sentinel,))
-        parent_sentinel = os.dup(w)
+        self.finalizer = util.Finalize(self, os.close, (self._parent_w,))
         with open(w, 'wb', closefd=True) as f:
             f.write(buf.getbuffer())
         self.pid = forkserver.read_signed(self.sentinel)
diff --git a/Lib/multiprocessing/popen_spawn_posix.py b/Lib/multiprocessing/popen_spawn_posix.py
index d8ce4cbe54031c..cbcd1c281bb7ca 100644
--- a/Lib/multiprocessing/popen_spawn_posix.py
+++ b/Lib/multiprocessing/popen_spawn_posix.py
@@ -63,6 +63,8 @@ def _launch(self, process_obj):
         finally:
             if parent_r is not None:
                 self.finalizer = util.Finalize(self, os.close, (parent_r,))
+            if parent_w is not None:
+                self.finalizer = util.Finalize(self, os.close, (parent_w,))
             for fd in (child_r, child_w):
                 if fd is not None:
                     os.close(fd)
diff --git a/Lib/multiprocessing/popen_spawn_win32.py b/Lib/multiprocessing/popen_spawn_win32.py
index f7e0bdcac3ca3b..de4c5ecf1fa083 100644
--- a/Lib/multiprocessing/popen_spawn_win32.py
+++ b/Lib/multiprocessing/popen_spawn_win32.py
@@ -68,7 +68,7 @@ def __init__(self, process_obj):
         else:
             env = None
 
-        with open(wfd, 'wb', closefd=False) as to_child:
+        with open(wfd, 'wb', closefd=True) as to_child:
             # start process
             try:
                 hp, ht, pid, tid = _winapi.CreateProcess(
diff --git a/Lib/multiprocessing/process.py b/Lib/multiprocessing/process.py
index 0364ea140abe3f..5fa3bdf526e6aa 100644
--- a/Lib/multiprocessing/process.py
+++ b/Lib/multiprocessing/process.py
@@ -365,9 +365,6 @@ def __init__(self, name, pid, sentinel):
         self._sentinel = sentinel
         self._config = {}
 
-    def close(self):
-        pass
-
     def is_alive(self):
         from multiprocessing.connection import wait
         return not wait([self._sentinel], timeout=0)
@@ -376,6 +373,13 @@ def is_alive(self):
     def ident(self):
         return self._pid
 
+    def join(self, timeout=None):
+        '''
+        Wait until parent process terminates
+        '''
+        from multiprocessing.connection import wait
+        wait([self._sentinel], timeout=5)
+
     pid = ident
 
 #
diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py
index c70c93b2b443b7..ac4e7f518e0af8 100644
--- a/Lib/test/_test_multiprocessing.py
+++ b/Lib/test/_test_multiprocessing.py
@@ -326,9 +326,7 @@ def _test_report_parent_status(cls, wconn):
         wconn.send("alive" if parent_process().is_alive() else "not alive")
 
         start_time = time.monotonic()
-        while (parent_process().is_alive() and
-               (time.monotonic() - start_time) < 5):
-            time.sleep(0.1)
+        parent_process().join(timeout=5)
 
         wconn.send("alive" if parent_process().is_alive() else "not alive")
 

From 7293d4cdb3e30255ecca035687854baea2b63278 Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Mon, 20 May 2019 19:59:04 +0200
Subject: [PATCH 23/25] FIX pass timeout correctly

---
 Lib/multiprocessing/process.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Lib/multiprocessing/process.py b/Lib/multiprocessing/process.py
index 5fa3bdf526e6aa..c62c826cff9580 100644
--- a/Lib/multiprocessing/process.py
+++ b/Lib/multiprocessing/process.py
@@ -378,7 +378,7 @@ def join(self, timeout=None):
         Wait until parent process terminates
         '''
         from multiprocessing.connection import wait
-        wait([self._sentinel], timeout=5)
+        wait([self._sentinel], timeout=timeout)
 
     pid = ident
 

From 80dcabf94e359080326899a836f5aa8f3bd2deb5 Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Mon, 20 May 2019 20:51:34 +0200
Subject: [PATCH 24/25] address review comments

---
 Lib/multiprocessing/popen_fork.py        |  4 ++--
 Lib/multiprocessing/popen_forkserver.py  |  6 +++---
 Lib/multiprocessing/popen_spawn_posix.py | 10 ++++++----
 Lib/multiprocessing/util.py              |  6 ++++++
 Lib/test/_test_multiprocessing.py        |  3 ---
 5 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/Lib/multiprocessing/popen_fork.py b/Lib/multiprocessing/popen_fork.py
index 02551a9d1b4d46..36599d8be0bace 100644
--- a/Lib/multiprocessing/popen_fork.py
+++ b/Lib/multiprocessing/popen_fork.py
@@ -78,8 +78,8 @@ def _launch(self, process_obj):
         else:
             os.close(child_w)
             os.close(child_r)
-            self.finalizer = util.Finalize(self, os.close, (parent_r,))
-            self.finalizer = util.Finalize(self, os.close, (parent_w,))
+            self.finalizer = util.Finalize(self, util.close_fds,
+                                           (parent_r, parent_w,))
             self.sentinel = parent_r
             self._parent_w = parent_w
 
diff --git a/Lib/multiprocessing/popen_forkserver.py b/Lib/multiprocessing/popen_forkserver.py
index c7c45473fa86d1..a56eb9bf11080b 100644
--- a/Lib/multiprocessing/popen_forkserver.py
+++ b/Lib/multiprocessing/popen_forkserver.py
@@ -51,9 +51,9 @@ def _launch(self, process_obj):
         self.sentinel, w = forkserver.connect_to_new_process(self._fds)
         # Keep a duplicate of the data pipe's write end as a sentinel of the
         # parent process used by the child process.
-        self._parent_w = os.dup(w)
-        self.finalizer = util.Finalize(self, os.close, (self.sentinel,))
-        self.finalizer = util.Finalize(self, os.close, (self._parent_w,))
+        _parent_w = os.dup(w)
+        self.finalizer = util.Finalize(self, util.close_fds,
+                                       (_parent_w, self.sentinel))
         with open(w, 'wb', closefd=True) as f:
             f.write(buf.getbuffer())
         self.pid = forkserver.read_signed(self.sentinel)
diff --git a/Lib/multiprocessing/popen_spawn_posix.py b/Lib/multiprocessing/popen_spawn_posix.py
index cbcd1c281bb7ca..24b8634523e5f2 100644
--- a/Lib/multiprocessing/popen_spawn_posix.py
+++ b/Lib/multiprocessing/popen_spawn_posix.py
@@ -61,10 +61,12 @@ def _launch(self, process_obj):
             with open(parent_w, 'wb', closefd=False) as f:
                 f.write(fp.getbuffer())
         finally:
-            if parent_r is not None:
-                self.finalizer = util.Finalize(self, os.close, (parent_r,))
-            if parent_w is not None:
-                self.finalizer = util.Finalize(self, os.close, (parent_w,))
+            fds_to_close = []
+            for fd in (parent_r, parent_w):
+                if fd is not None:
+                    fds_to_close.append(fd)
+            self.finalizer = util.Finalize(self, util.close_fds, fds_to_close)
+
             for fd in (child_r, child_w):
                 if fd is not None:
                     os.close(fd)
diff --git a/Lib/multiprocessing/util.py b/Lib/multiprocessing/util.py
index 0c4eb2473273b4..5674ad773f9764 100644
--- a/Lib/multiprocessing/util.py
+++ b/Lib/multiprocessing/util.py
@@ -421,3 +421,9 @@ def spawnv_passfds(path, args, passfds):
     finally:
         os.close(errpipe_read)
         os.close(errpipe_write)
+
+
+def close_fds(*fds):
+    """Close each file descriptor given as an argument"""
+    for fd in fds:
+        os.close(fd)
diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py
index ac4e7f518e0af8..ed5a9a18860e64 100644
--- a/Lib/test/_test_multiprocessing.py
+++ b/Lib/test/_test_multiprocessing.py
@@ -324,10 +324,7 @@ def _test_create_grandchild_process(cls, wconn):
     def _test_report_parent_status(cls, wconn):
         from multiprocessing.process import parent_process
         wconn.send("alive" if parent_process().is_alive() else "not alive")
-
-        start_time = time.monotonic()
         parent_process().join(timeout=5)
-
         wconn.send("alive" if parent_process().is_alive() else "not alive")
 
     def test_process(self):

From 32aa64063b48ec32063a7b1e1554c947c9392819 Mon Sep 17 00:00:00 2001
From: Pierre Glaser <pierreglaser@msn.com>
Date: Mon, 20 May 2019 20:56:24 +0200
Subject: [PATCH 25/25] CLN unnecessary attribute

---
 Lib/multiprocessing/popen_fork.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Lib/multiprocessing/popen_fork.py b/Lib/multiprocessing/popen_fork.py
index 36599d8be0bace..11e216072d0919 100644
--- a/Lib/multiprocessing/popen_fork.py
+++ b/Lib/multiprocessing/popen_fork.py
@@ -81,7 +81,6 @@ def _launch(self, process_obj):
             self.finalizer = util.Finalize(self, util.close_fds,
                                            (parent_r, parent_w,))
             self.sentinel = parent_r
-            self._parent_w = parent_w
 
     def close(self):
         if self.finalizer is not None: