bpo-45847: Fix _multiprocessing on platforms without sem_open (GH-29833)

4 files changed, 84 insertions, 11 deletions

diff --git a/Modules/_multiprocessing/clinic/semaphore.c.h b/Modules/_multiprocessing/clinic/semaphore.c.h
index e1b9309e9f..018447ad13 100644
--- a/Modules/_multiprocessing/clinic/semaphore.c.h
+++ b/Modules/_multiprocessing/clinic/semaphore.c.h
@@ -2,7 +2,7 @@
 preserve
 [clinic start generated code]*/
 
-#if defined(MS_WINDOWS)
+#if defined(HAVE_MP_SEMAPHORE) && defined(MS_WINDOWS)
 
 PyDoc_STRVAR(_multiprocessing_SemLock_acquire__doc__,
 "acquire($self, /, block=True, timeout=None)\n"
@@ -52,9 +52,9 @@ exit:
     return return_value;
 }
 
-#endif /* defined(MS_WINDOWS) */
+#endif /* defined(HAVE_MP_SEMAPHORE) && defined(MS_WINDOWS) */
 
-#if defined(MS_WINDOWS)
+#if defined(HAVE_MP_SEMAPHORE) && defined(MS_WINDOWS)
 
 PyDoc_STRVAR(_multiprocessing_SemLock_release__doc__,
 "release($self, /)\n"
@@ -74,9 +74,9 @@ _multiprocessing_SemLock_release(SemLockObject *self, PyObject *Py_UNUSED(ignore
     return _multiprocessing_SemLock_release_impl(self);
 }
 
-#endif /* defined(MS_WINDOWS) */
+#endif /* defined(HAVE_MP_SEMAPHORE) && defined(MS_WINDOWS) */
 
-#if !defined(MS_WINDOWS)
+#if defined(HAVE_MP_SEMAPHORE) && !defined(MS_WINDOWS)
 
 PyDoc_STRVAR(_multiprocessing_SemLock_acquire__doc__,
 "acquire($self, /, block=True, timeout=None)\n"
@@ -126,9 +126,9 @@ exit:
     return return_value;
 }
 
-#endif /* !defined(MS_WINDOWS) */
+#endif /* defined(HAVE_MP_SEMAPHORE) && !defined(MS_WINDOWS) */
 
-#if !defined(MS_WINDOWS)
+#if defined(HAVE_MP_SEMAPHORE) && !defined(MS_WINDOWS)
 
 PyDoc_STRVAR(_multiprocessing_SemLock_release__doc__,
 "release($self, /)\n"
@@ -148,7 +148,9 @@ _multiprocessing_SemLock_release(SemLockObject *self, PyObject *Py_UNUSED(ignore
     return _multiprocessing_SemLock_release_impl(self);
 }
 
-#endif /* !defined(MS_WINDOWS) */
+#endif /* defined(HAVE_MP_SEMAPHORE) && !defined(MS_WINDOWS) */
+
+#if defined(HAVE_MP_SEMAPHORE)
 
 static PyObject *
 _multiprocessing_SemLock_impl(PyTypeObject *type, int kind, int value,
@@ -208,6 +210,10 @@ exit:
     return return_value;
 }
 
+#endif /* defined(HAVE_MP_SEMAPHORE) */
+
+#if defined(HAVE_MP_SEMAPHORE)
+
 PyDoc_STRVAR(_multiprocessing_SemLock__rebuild__doc__,
 "_rebuild($type, handle, kind, maxvalue, name, /)\n"
 "--\n"
@@ -240,6 +246,10 @@ exit:
     return return_value;
 }
 
+#endif /* defined(HAVE_MP_SEMAPHORE) */
+
+#if defined(HAVE_MP_SEMAPHORE)
+
 PyDoc_STRVAR(_multiprocessing_SemLock__count__doc__,
 "_count($self, /)\n"
 "--\n"
@@ -258,6 +268,10 @@ _multiprocessing_SemLock__count(SemLockObject *self, PyObject *Py_UNUSED(ignored
     return _multiprocessing_SemLock__count_impl(self);
 }
 
+#endif /* defined(HAVE_MP_SEMAPHORE) */
+
+#if defined(HAVE_MP_SEMAPHORE)
+
 PyDoc_STRVAR(_multiprocessing_SemLock__is_mine__doc__,
 "_is_mine($self, /)\n"
 "--\n"
@@ -276,6 +290,10 @@ _multiprocessing_SemLock__is_mine(SemLockObject *self, PyObject *Py_UNUSED(ignor
     return _multiprocessing_SemLock__is_mine_impl(self);
 }
 
+#endif /* defined(HAVE_MP_SEMAPHORE) */
+
+#if defined(HAVE_MP_SEMAPHORE)
+
 PyDoc_STRVAR(_multiprocessing_SemLock__get_value__doc__,
 "_get_value($self, /)\n"
 "--\n"
@@ -294,6 +312,10 @@ _multiprocessing_SemLock__get_value(SemLockObject *self, PyObject *Py_UNUSED(ign
     return _multiprocessing_SemLock__get_value_impl(self);
 }
 
+#endif /* defined(HAVE_MP_SEMAPHORE) */
+
+#if defined(HAVE_MP_SEMAPHORE)
+
 PyDoc_STRVAR(_multiprocessing_SemLock__is_zero__doc__,
 "_is_zero($self, /)\n"
 "--\n"
@@ -312,6 +334,10 @@ _multiprocessing_SemLock__is_zero(SemLockObject *self, PyObject *Py_UNUSED(ignor
     return _multiprocessing_SemLock__is_zero_impl(self);
 }
 
+#endif /* defined(HAVE_MP_SEMAPHORE) */
+
+#if defined(HAVE_MP_SEMAPHORE)
+
 PyDoc_STRVAR(_multiprocessing_SemLock__after_fork__doc__,
 "_after_fork($self, /)\n"
 "--\n"
@@ -330,6 +356,10 @@ _multiprocessing_SemLock__after_fork(SemLockObject *self, PyObject *Py_UNUSED(ig
     return _multiprocessing_SemLock__after_fork_impl(self);
 }
 
+#endif /* defined(HAVE_MP_SEMAPHORE) */
+
+#if defined(HAVE_MP_SEMAPHORE)
+
 PyDoc_STRVAR(_multiprocessing_SemLock___enter____doc__,
 "__enter__($self, /)\n"
 "--\n"
@@ -348,6 +378,10 @@ _multiprocessing_SemLock___enter__(SemLockObject *self, PyObject *Py_UNUSED(igno
     return _multiprocessing_SemLock___enter___impl(self);
 }
 
+#endif /* defined(HAVE_MP_SEMAPHORE) */
+
+#if defined(HAVE_MP_SEMAPHORE)
+
 PyDoc_STRVAR(_multiprocessing_SemLock___exit____doc__,
 "__exit__($self, exc_type=None, exc_value=None, exc_tb=None, /)\n"
 "--\n"
@@ -392,6 +426,8 @@ exit:
     return return_value;
 }
 
+#endif /* defined(HAVE_MP_SEMAPHORE) */
+
 #ifndef _MULTIPROCESSING_SEMLOCK_ACQUIRE_METHODDEF
     #define _MULTIPROCESSING_SEMLOCK_ACQUIRE_METHODDEF
 #endif /* !defined(_MULTIPROCESSING_SEMLOCK_ACQUIRE_METHODDEF) */
@@ -399,4 +435,36 @@ exit:
 #ifndef _MULTIPROCESSING_SEMLOCK_RELEASE_METHODDEF
     #define _MULTIPROCESSING_SEMLOCK_RELEASE_METHODDEF
 #endif /* !defined(_MULTIPROCESSING_SEMLOCK_RELEASE_METHODDEF) */
-/*[clinic end generated code: output=e7fd938150601fe5 input=a9049054013a1b77]*/
+
+#ifndef _MULTIPROCESSING_SEMLOCK__REBUILD_METHODDEF
+    #define _MULTIPROCESSING_SEMLOCK__REBUILD_METHODDEF
+#endif /* !defined(_MULTIPROCESSING_SEMLOCK__REBUILD_METHODDEF) */
+
+#ifndef _MULTIPROCESSING_SEMLOCK__COUNT_METHODDEF
+    #define _MULTIPROCESSING_SEMLOCK__COUNT_METHODDEF
+#endif /* !defined(_MULTIPROCESSING_SEMLOCK__COUNT_METHODDEF) */
+
+#ifndef _MULTIPROCESSING_SEMLOCK__IS_MINE_METHODDEF
+    #define _MULTIPROCESSING_SEMLOCK__IS_MINE_METHODDEF
+#endif /* !defined(_MULTIPROCESSING_SEMLOCK__IS_MINE_METHODDEF) */
+
+#ifndef _MULTIPROCESSING_SEMLOCK__GET_VALUE_METHODDEF
+    #define _MULTIPROCESSING_SEMLOCK__GET_VALUE_METHODDEF
+#endif /* !defined(_MULTIPROCESSING_SEMLOCK__GET_VALUE_METHODDEF) */
+
+#ifndef _MULTIPROCESSING_SEMLOCK__IS_ZERO_METHODDEF
+    #define _MULTIPROCESSING_SEMLOCK__IS_ZERO_METHODDEF
+#endif /* !defined(_MULTIPROCESSING_SEMLOCK__IS_ZERO_METHODDEF) */
+
+#ifndef _MULTIPROCESSING_SEMLOCK__AFTER_FORK_METHODDEF
+    #define _MULTIPROCESSING_SEMLOCK__AFTER_FORK_METHODDEF
+#endif /* !defined(_MULTIPROCESSING_SEMLOCK__AFTER_FORK_METHODDEF) */
+
+#ifndef _MULTIPROCESSING_SEMLOCK___ENTER___METHODDEF
+    #define _MULTIPROCESSING_SEMLOCK___ENTER___METHODDEF
+#endif /* !defined(_MULTIPROCESSING_SEMLOCK___ENTER___METHODDEF) */
+
+#ifndef _MULTIPROCESSING_SEMLOCK___EXIT___METHODDEF
+    #define _MULTIPROCESSING_SEMLOCK___EXIT___METHODDEF
+#endif /* !defined(_MULTIPROCESSING_SEMLOCK___EXIT___METHODDEF) */
+/*[clinic end generated code: output=fde05a081b5bdba4 input=a9049054013a1b77]*/
diff --git a/Modules/_multiprocessing/multiprocessing.c b/Modules/_multiprocessing/multiprocessing.c
index bec23517fc..0809c2455d 100644
--- a/Modules/_multiprocessing/multiprocessing.c
+++ b/Modules/_multiprocessing/multiprocessing.c
@@ -186,8 +186,7 @@ static PyMethodDef module_methods[] = {
 static int
 multiprocessing_exec(PyObject *module)
 {
-#if defined(MS_WINDOWS) ||                                              \
-  (defined(HAVE_SEM_OPEN) && !defined(POSIX_SEMAPHORES_NOT_ENABLED))
+#ifdef HAVE_MP_SEMAPHORE
 
     /* Add _PyMp_SemLock type to module */
     if (PyModule_AddType(module, &_PyMp_SemLockType) < 0) {
diff --git a/Modules/_multiprocessing/multiprocessing.h b/Modules/_multiprocessing/multiprocessing.h
index 277963bc15..3a8314b1db 100644
--- a/Modules/_multiprocessing/multiprocessing.h
+++ b/Modules/_multiprocessing/multiprocessing.h
@@ -21,9 +21,11 @@
 #  endif
 #  define SEM_HANDLE HANDLE
 #  define SEM_VALUE_MAX LONG_MAX
+#  define HAVE_MP_SEMAPHORE
 #else
 #  include <fcntl.h>                 /* O_CREAT and O_EXCL */
 #  if defined(HAVE_SEM_OPEN) && !defined(POSIX_SEMAPHORES_NOT_ENABLED)
+#    define HAVE_MP_SEMAPHORE
 #    include <semaphore.h>
      typedef sem_t *SEM_HANDLE;
 #  endif
diff --git a/Modules/_multiprocessing/semaphore.c b/Modules/_multiprocessing/semaphore.c
index 9a2d1f85c9..8607476aff 100644
--- a/Modules/_multiprocessing/semaphore.c
+++ b/Modules/_multiprocessing/semaphore.c
@@ -9,6 +9,8 @@
 
 #include "multiprocessing.h"
 
+#ifdef HAVE_MP_SEMAPHORE
+
 enum { RECURSIVE_MUTEX, SEMAPHORE };
 
 typedef struct {
@@ -794,3 +796,5 @@ _PyMp_sem_unlink(const char *name)
 
     Py_RETURN_NONE;
 }
+
+#endif // HAVE_MP_SEMAPHORE