Library import 16 (#2433)

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1 files changed, 790 insertions, 0 deletions

diff --git a/contrib/tools/python3/Modules/_multiprocessing/semaphore.c b/contrib/tools/python3/Modules/_multiprocessing/semaphore.c
new file mode 100644
index 0000000000..c7df82dfe2
--- /dev/null
+++ b/contrib/tools/python3/Modules/_multiprocessing/semaphore.c
@@ -0,0 +1,790 @@
+/*
+ * A type which wraps a semaphore
+ *
+ * semaphore.c
+ *
+ * Copyright (c) 2006-2008, R Oudkerk
+ * Licensed to PSF under a Contributor Agreement.
+ */
+
+#include "multiprocessing.h"
+
+#ifdef HAVE_MP_SEMAPHORE
+
+enum { RECURSIVE_MUTEX, SEMAPHORE };
+
+typedef struct {
+    PyObject_HEAD
+    SEM_HANDLE handle;
+    unsigned long last_tid;
+    int count;
+    int maxvalue;
+    int kind;
+    char *name;
+} SemLockObject;
+
+/*[python input]
+class SEM_HANDLE_converter(CConverter):
+    type = "SEM_HANDLE"
+    format_unit = '"F_SEM_HANDLE"'
+
+[python start generated code]*/
+/*[python end generated code: output=da39a3ee5e6b4b0d input=3e0ad43e482d8716]*/
+
+/*[clinic input]
+module _multiprocessing
+class _multiprocessing.SemLock "SemLockObject *" "&_PyMp_SemLockType"
+[clinic start generated code]*/
+/*[clinic end generated code: output=da39a3ee5e6b4b0d input=935fb41b7d032599]*/
+
+#include "clinic/semaphore.c.h"
+
+#define ISMINE(o) (o->count > 0 && PyThread_get_thread_ident() == o->last_tid)
+
+
+#ifdef MS_WINDOWS
+
+/*
+ * Windows definitions
+ */
+
+#define SEM_FAILED NULL
+
+#define SEM_CLEAR_ERROR() SetLastError(0)
+#define SEM_GET_LAST_ERROR() GetLastError()
+#define SEM_CREATE(name, val, max) CreateSemaphore(NULL, val, max, NULL)
+#define SEM_CLOSE(sem) (CloseHandle(sem) ? 0 : -1)
+#define SEM_GETVALUE(sem, pval) _GetSemaphoreValue(sem, pval)
+#define SEM_UNLINK(name) 0
+
+static int
+_GetSemaphoreValue(HANDLE handle, long *value)
+{
+    long previous;
+
+    switch (WaitForSingleObjectEx(handle, 0, FALSE)) {
+    case WAIT_OBJECT_0:
+        if (!ReleaseSemaphore(handle, 1, &previous))
+            return MP_STANDARD_ERROR;
+        *value = previous + 1;
+        return 0;
+    case WAIT_TIMEOUT:
+        *value = 0;
+        return 0;
+    default:
+        return MP_STANDARD_ERROR;
+    }
+}
+
+/*[clinic input]
+_multiprocessing.SemLock.acquire
+
+    block as blocking: bool = True
+    timeout as timeout_obj: object = None
+
+Acquire the semaphore/lock.
+[clinic start generated code]*/
+
+static PyObject *
+_multiprocessing_SemLock_acquire_impl(SemLockObject *self, int blocking,
+                                      PyObject *timeout_obj)
+/*[clinic end generated code: output=f9998f0b6b0b0872 input=e5b45f5cbb775166]*/
+{
+    double timeout;
+    DWORD res, full_msecs, nhandles;
+    HANDLE handles[2], sigint_event;
+
+    /* calculate timeout */
+    if (!blocking) {
+        full_msecs = 0;
+    } else if (timeout_obj == Py_None) {
+        full_msecs = INFINITE;
+    } else {
+        timeout = PyFloat_AsDouble(timeout_obj);
+        if (PyErr_Occurred())
+            return NULL;
+        timeout *= 1000.0;      /* convert to millisecs */
+        if (timeout < 0.0) {
+            timeout = 0.0;
+        } else if (timeout >= 0.5 * INFINITE) { /* 25 days */
+            PyErr_SetString(PyExc_OverflowError,
+                            "timeout is too large");
+            return NULL;
+        }
+        full_msecs = (DWORD)(timeout + 0.5);
+    }
+
+    /* check whether we already own the lock */
+    if (self->kind == RECURSIVE_MUTEX && ISMINE(self)) {
+        ++self->count;
+        Py_RETURN_TRUE;
+    }
+
+    /* check whether we can acquire without releasing the GIL and blocking */
+    if (WaitForSingleObjectEx(self->handle, 0, FALSE) == WAIT_OBJECT_0) {
+        self->last_tid = GetCurrentThreadId();
+        ++self->count;
+        Py_RETURN_TRUE;
+    }
+
+    /* prepare list of handles */
+    nhandles = 0;
+    handles[nhandles++] = self->handle;
+    if (_PyOS_IsMainThread()) {
+        sigint_event = _PyOS_SigintEvent();
+        assert(sigint_event != NULL);
+        handles[nhandles++] = sigint_event;
+    }
+    else {
+        sigint_event = NULL;
+    }
+
+    /* do the wait */
+    Py_BEGIN_ALLOW_THREADS
+    if (sigint_event != NULL)
+        ResetEvent(sigint_event);
+    res = WaitForMultipleObjectsEx(nhandles, handles, FALSE, full_msecs, FALSE);
+    Py_END_ALLOW_THREADS
+
+    /* handle result */
+    switch (res) {
+    case WAIT_TIMEOUT:
+        Py_RETURN_FALSE;
+    case WAIT_OBJECT_0 + 0:
+        self->last_tid = GetCurrentThreadId();
+        ++self->count;
+        Py_RETURN_TRUE;
+    case WAIT_OBJECT_0 + 1:
+        errno = EINTR;
+        return PyErr_SetFromErrno(PyExc_OSError);
+    case WAIT_FAILED:
+        return PyErr_SetFromWindowsErr(0);
+    default:
+        PyErr_Format(PyExc_RuntimeError, "WaitForSingleObject() or "
+                     "WaitForMultipleObjects() gave unrecognized "
+                     "value %u", res);
+        return NULL;
+    }
+}
+
+/*[clinic input]
+_multiprocessing.SemLock.release
+
+Release the semaphore/lock.
+[clinic start generated code]*/
+
+static PyObject *
+_multiprocessing_SemLock_release_impl(SemLockObject *self)
+/*[clinic end generated code: output=b22f53ba96b0d1db input=ba7e63a961885d3d]*/
+{
+    if (self->kind == RECURSIVE_MUTEX) {
+        if (!ISMINE(self)) {
+            PyErr_SetString(PyExc_AssertionError, "attempt to "
+                            "release recursive lock not owned "
+                            "by thread");
+            return NULL;
+        }
+        if (self->count > 1) {
+            --self->count;
+            Py_RETURN_NONE;
+        }
+        assert(self->count == 1);
+    }
+
+    if (!ReleaseSemaphore(self->handle, 1, NULL)) {
+        if (GetLastError() == ERROR_TOO_MANY_POSTS) {
+            PyErr_SetString(PyExc_ValueError, "semaphore or lock "
+                            "released too many times");
+            return NULL;
+        } else {
+            return PyErr_SetFromWindowsErr(0);
+        }
+    }
+
+    --self->count;
+    Py_RETURN_NONE;
+}
+
+#else /* !MS_WINDOWS */
+
+/*
+ * Unix definitions
+ */
+
+#define SEM_CLEAR_ERROR()
+#define SEM_GET_LAST_ERROR() 0
+#define SEM_CREATE(name, val, max) sem_open(name, O_CREAT | O_EXCL, 0600, val)
+#define SEM_CLOSE(sem) sem_close(sem)
+#define SEM_GETVALUE(sem, pval) sem_getvalue(sem, pval)
+#define SEM_UNLINK(name) sem_unlink(name)
+
+/* OS X 10.4 defines SEM_FAILED as -1 instead of (sem_t *)-1;  this gives
+   compiler warnings, and (potentially) undefined behaviour. */
+#ifdef __APPLE__
+#  undef SEM_FAILED
+#  define SEM_FAILED ((sem_t *)-1)
+#endif
+
+#ifndef HAVE_SEM_UNLINK
+#  define sem_unlink(name) 0
+#endif
+
+#ifndef HAVE_SEM_TIMEDWAIT
+#  define sem_timedwait(sem,deadline) sem_timedwait_save(sem,deadline,_save)
+
+static int
+sem_timedwait_save(sem_t *sem, struct timespec *deadline, PyThreadState *_save)
+{
+    int res;
+    unsigned long delay, difference;
+    struct timeval now, tvdeadline, tvdelay;
+
+    errno = 0;
+    tvdeadline.tv_sec = deadline->tv_sec;
+    tvdeadline.tv_usec = deadline->tv_nsec / 1000;
+
+    for (delay = 0 ; ; delay += 1000) {
+        /* poll */
+        if (sem_trywait(sem) == 0)
+            return 0;
+        else if (errno != EAGAIN)
+            return MP_STANDARD_ERROR;
+
+        /* get current time */
+        if (gettimeofday(&now, NULL) < 0)
+            return MP_STANDARD_ERROR;
+
+        /* check for timeout */
+        if (tvdeadline.tv_sec < now.tv_sec ||
+            (tvdeadline.tv_sec == now.tv_sec &&
+             tvdeadline.tv_usec <= now.tv_usec)) {
+            errno = ETIMEDOUT;
+            return MP_STANDARD_ERROR;
+        }
+
+        /* calculate how much time is left */
+        difference = (tvdeadline.tv_sec - now.tv_sec) * 1000000 +
+            (tvdeadline.tv_usec - now.tv_usec);
+
+        /* check delay not too long -- maximum is 20 msecs */
+        if (delay > 20000)
+            delay = 20000;
+        if (delay > difference)
+            delay = difference;
+
+        /* sleep */
+        tvdelay.tv_sec = delay / 1000000;
+        tvdelay.tv_usec = delay % 1000000;
+        if (select(0, NULL, NULL, NULL, &tvdelay) < 0)
+            return MP_STANDARD_ERROR;
+
+        /* check for signals */
+        Py_BLOCK_THREADS
+        res = PyErr_CheckSignals();
+        Py_UNBLOCK_THREADS
+
+        if (res) {
+            errno = EINTR;
+            return MP_EXCEPTION_HAS_BEEN_SET;
+        }
+    }
+}
+
+#endif /* !HAVE_SEM_TIMEDWAIT */
+
+/*[clinic input]
+_multiprocessing.SemLock.acquire
+
+    block as blocking: bool = True
+    timeout as timeout_obj: object = None
+
+Acquire the semaphore/lock.
+[clinic start generated code]*/
+
+static PyObject *
+_multiprocessing_SemLock_acquire_impl(SemLockObject *self, int blocking,
+                                      PyObject *timeout_obj)
+/*[clinic end generated code: output=f9998f0b6b0b0872 input=e5b45f5cbb775166]*/
+{
+    int res, err = 0;
+    struct timespec deadline = {0};
+
+    if (self->kind == RECURSIVE_MUTEX && ISMINE(self)) {
+        ++self->count;
+        Py_RETURN_TRUE;
+    }
+
+    int use_deadline = (timeout_obj != Py_None);
+    if (use_deadline) {
+        double timeout = PyFloat_AsDouble(timeout_obj);
+        if (PyErr_Occurred()) {
+            return NULL;
+        }
+        if (timeout < 0.0) {
+            timeout = 0.0;
+        }
+
+        struct timeval now;
+        if (gettimeofday(&now, NULL) < 0) {
+            PyErr_SetFromErrno(PyExc_OSError);
+            return NULL;
+        }
+        long sec = (long) timeout;
+        long nsec = (long) (1e9 * (timeout - sec) + 0.5);
+        deadline.tv_sec = now.tv_sec + sec;
+        deadline.tv_nsec = now.tv_usec * 1000 + nsec;
+        deadline.tv_sec += (deadline.tv_nsec / 1000000000);
+        deadline.tv_nsec %= 1000000000;
+    }
+
+    /* Check whether we can acquire without releasing the GIL and blocking */
+    do {
+        res = sem_trywait(self->handle);
+        err = errno;
+    } while (res < 0 && errno == EINTR && !PyErr_CheckSignals());
+    errno = err;
+
+    if (res < 0 && errno == EAGAIN && blocking) {
+        /* Couldn't acquire immediately, need to block */
+        do {
+            Py_BEGIN_ALLOW_THREADS
+            if (!use_deadline) {
+                res = sem_wait(self->handle);
+            }
+            else {
+                res = sem_timedwait(self->handle, &deadline);
+            }
+            Py_END_ALLOW_THREADS
+            err = errno;
+            if (res == MP_EXCEPTION_HAS_BEEN_SET)
+                break;
+        } while (res < 0 && errno == EINTR && !PyErr_CheckSignals());
+    }
+
+    if (res < 0) {
+        errno = err;
+        if (errno == EAGAIN || errno == ETIMEDOUT)
+            Py_RETURN_FALSE;
+        else if (errno == EINTR)
+            return NULL;
+        else
+            return PyErr_SetFromErrno(PyExc_OSError);
+    }
+
+    ++self->count;
+    self->last_tid = PyThread_get_thread_ident();
+
+    Py_RETURN_TRUE;
+}
+
+/*[clinic input]
+_multiprocessing.SemLock.release
+
+Release the semaphore/lock.
+[clinic start generated code]*/
+
+static PyObject *
+_multiprocessing_SemLock_release_impl(SemLockObject *self)
+/*[clinic end generated code: output=b22f53ba96b0d1db input=ba7e63a961885d3d]*/
+{
+    if (self->kind == RECURSIVE_MUTEX) {
+        if (!ISMINE(self)) {
+            PyErr_SetString(PyExc_AssertionError, "attempt to "
+                            "release recursive lock not owned "
+                            "by thread");
+            return NULL;
+        }
+        if (self->count > 1) {
+            --self->count;
+            Py_RETURN_NONE;
+        }
+        assert(self->count == 1);
+    } else {
+#ifdef HAVE_BROKEN_SEM_GETVALUE
+        /* We will only check properly the maxvalue == 1 case */
+        if (self->maxvalue == 1) {
+            /* make sure that already locked */
+            if (sem_trywait(self->handle) < 0) {
+                if (errno != EAGAIN) {
+                    PyErr_SetFromErrno(PyExc_OSError);
+                    return NULL;
+                }
+                /* it is already locked as expected */
+            } else {
+                /* it was not locked so undo wait and raise  */
+                if (sem_post(self->handle) < 0) {
+                    PyErr_SetFromErrno(PyExc_OSError);
+                    return NULL;
+                }
+                PyErr_SetString(PyExc_ValueError, "semaphore "
+                                "or lock released too many "
+                                "times");
+                return NULL;
+            }
+        }
+#else
+        int sval;
+
+        /* This check is not an absolute guarantee that the semaphore
+           does not rise above maxvalue. */
+        if (sem_getvalue(self->handle, &sval) < 0) {
+            return PyErr_SetFromErrno(PyExc_OSError);
+        } else if (sval >= self->maxvalue) {
+            PyErr_SetString(PyExc_ValueError, "semaphore or lock "
+                            "released too many times");
+            return NULL;
+        }
+#endif
+    }
+
+    if (sem_post(self->handle) < 0)
+        return PyErr_SetFromErrno(PyExc_OSError);
+
+    --self->count;
+    Py_RETURN_NONE;
+}
+
+#endif /* !MS_WINDOWS */
+
+/*
+ * All platforms
+ */
+
+static PyObject *
+newsemlockobject(PyTypeObject *type, SEM_HANDLE handle, int kind, int maxvalue,
+                 char *name)
+{
+    SemLockObject *self = (SemLockObject *)type->tp_alloc(type, 0);
+    if (!self)
+        return NULL;
+    self->handle = handle;
+    self->kind = kind;
+    self->count = 0;
+    self->last_tid = 0;
+    self->maxvalue = maxvalue;
+    self->name = name;
+    return (PyObject*)self;
+}
+
+/*[clinic input]
+@classmethod
+_multiprocessing.SemLock.__new__
+
+    kind: int
+    value: int
+    maxvalue: int
+    name: str
+    unlink: bool
+
+[clinic start generated code]*/
+
+static PyObject *
+_multiprocessing_SemLock_impl(PyTypeObject *type, int kind, int value,
+                              int maxvalue, const char *name, int unlink)
+/*[clinic end generated code: output=30727e38f5f7577a input=fdaeb69814471c5b]*/
+{
+    SEM_HANDLE handle = SEM_FAILED;
+    PyObject *result;
+    char *name_copy = NULL;
+
+    if (kind != RECURSIVE_MUTEX && kind != SEMAPHORE) {
+        PyErr_SetString(PyExc_ValueError, "unrecognized kind");
+        return NULL;
+    }
+
+    if (!unlink) {
+        name_copy = PyMem_Malloc(strlen(name) + 1);
+        if (name_copy == NULL) {
+            return PyErr_NoMemory();
+        }
+        strcpy(name_copy, name);
+    }
+
+    SEM_CLEAR_ERROR();
+    handle = SEM_CREATE(name, value, maxvalue);
+    /* On Windows we should fail if GetLastError()==ERROR_ALREADY_EXISTS */
+    if (handle == SEM_FAILED || SEM_GET_LAST_ERROR() != 0)
+        goto failure;
+
+    if (unlink && SEM_UNLINK(name) < 0)
+        goto failure;
+
+    result = newsemlockobject(type, handle, kind, maxvalue, name_copy);
+    if (!result)
+        goto failure;
+
+    return result;
+
+  failure:
+    if (!PyErr_Occurred()) {
+        _PyMp_SetError(NULL, MP_STANDARD_ERROR);
+    }
+    if (handle != SEM_FAILED)
+        SEM_CLOSE(handle);
+    PyMem_Free(name_copy);
+    return NULL;
+}
+
+/*[clinic input]
+@classmethod
+_multiprocessing.SemLock._rebuild
+
+    handle: SEM_HANDLE
+    kind: int
+    maxvalue: int
+    name: str(accept={str, NoneType})
+    /
+
+[clinic start generated code]*/
+
+static PyObject *
+_multiprocessing_SemLock__rebuild_impl(PyTypeObject *type, SEM_HANDLE handle,
+                                       int kind, int maxvalue,
+                                       const char *name)
+/*[clinic end generated code: output=2aaee14f063f3bd9 input=f7040492ac6d9962]*/
+{
+    char *name_copy = NULL;
+
+    if (name != NULL) {
+        name_copy = PyMem_Malloc(strlen(name) + 1);
+        if (name_copy == NULL)
+            return PyErr_NoMemory();
+        strcpy(name_copy, name);
+    }
+
+#ifndef MS_WINDOWS
+    if (name != NULL) {
+        handle = sem_open(name, 0);
+        if (handle == SEM_FAILED) {
+            PyErr_SetFromErrno(PyExc_OSError);
+            PyMem_Free(name_copy);
+            return NULL;
+        }
+    }
+#endif
+
+    return newsemlockobject(type, handle, kind, maxvalue, name_copy);
+}
+
+static void
+semlock_dealloc(SemLockObject* self)
+{
+    PyTypeObject *tp = Py_TYPE(self);
+    PyObject_GC_UnTrack(self);
+    if (self->handle != SEM_FAILED)
+        SEM_CLOSE(self->handle);
+    PyMem_Free(self->name);
+    tp->tp_free(self);
+    Py_DECREF(tp);
+}
+
+/*[clinic input]
+_multiprocessing.SemLock._count
+
+Num of `acquire()`s minus num of `release()`s for this process.
+[clinic start generated code]*/
+
+static PyObject *
+_multiprocessing_SemLock__count_impl(SemLockObject *self)
+/*[clinic end generated code: output=5ba8213900e517bb input=36fc59b1cd1025ab]*/
+{
+    return PyLong_FromLong((long)self->count);
+}
+
+/*[clinic input]
+_multiprocessing.SemLock._is_mine
+
+Whether the lock is owned by this thread.
+[clinic start generated code]*/
+
+static PyObject *
+_multiprocessing_SemLock__is_mine_impl(SemLockObject *self)
+/*[clinic end generated code: output=92dc98863f4303be input=a96664cb2f0093ba]*/
+{
+    /* only makes sense for a lock */
+    return PyBool_FromLong(ISMINE(self));
+}
+
+/*[clinic input]
+_multiprocessing.SemLock._get_value
+
+Get the value of the semaphore.
+[clinic start generated code]*/
+
+static PyObject *
+_multiprocessing_SemLock__get_value_impl(SemLockObject *self)
+/*[clinic end generated code: output=64bc1b89bda05e36 input=cb10f9a769836203]*/
+{
+#ifdef HAVE_BROKEN_SEM_GETVALUE
+    PyErr_SetNone(PyExc_NotImplementedError);
+    return NULL;
+#else
+    int sval;
+    if (SEM_GETVALUE(self->handle, &sval) < 0)
+        return _PyMp_SetError(NULL, MP_STANDARD_ERROR);
+    /* some posix implementations use negative numbers to indicate
+       the number of waiting threads */
+    if (sval < 0)
+        sval = 0;
+    return PyLong_FromLong((long)sval);
+#endif
+}
+
+/*[clinic input]
+_multiprocessing.SemLock._is_zero
+
+Return whether semaphore has value zero.
+[clinic start generated code]*/
+
+static PyObject *
+_multiprocessing_SemLock__is_zero_impl(SemLockObject *self)
+/*[clinic end generated code: output=815d4c878c806ed7 input=294a446418d31347]*/
+{
+#ifdef HAVE_BROKEN_SEM_GETVALUE
+    if (sem_trywait(self->handle) < 0) {
+        if (errno == EAGAIN)
+            Py_RETURN_TRUE;
+        return _PyMp_SetError(NULL, MP_STANDARD_ERROR);
+    } else {
+        if (sem_post(self->handle) < 0)
+            return _PyMp_SetError(NULL, MP_STANDARD_ERROR);
+        Py_RETURN_FALSE;
+    }
+#else
+    int sval;
+    if (SEM_GETVALUE(self->handle, &sval) < 0)
+        return _PyMp_SetError(NULL, MP_STANDARD_ERROR);
+    return PyBool_FromLong((long)sval == 0);
+#endif
+}
+
+/*[clinic input]
+_multiprocessing.SemLock._after_fork
+
+Rezero the net acquisition count after fork().
+[clinic start generated code]*/
+
+static PyObject *
+_multiprocessing_SemLock__after_fork_impl(SemLockObject *self)
+/*[clinic end generated code: output=718bb27914c6a6c1 input=190991008a76621e]*/
+{
+    self->count = 0;
+    Py_RETURN_NONE;
+}
+
+/*[clinic input]
+_multiprocessing.SemLock.__enter__
+
+Enter the semaphore/lock.
+[clinic start generated code]*/
+
+static PyObject *
+_multiprocessing_SemLock___enter___impl(SemLockObject *self)
+/*[clinic end generated code: output=beeb2f07c858511f input=c5e27d594284690b]*/
+{
+    return _multiprocessing_SemLock_acquire_impl(self, 1, Py_None);
+}
+
+/*[clinic input]
+_multiprocessing.SemLock.__exit__
+
+    exc_type: object = None
+    exc_value: object = None
+    exc_tb: object = None
+    /
+
+Exit the semaphore/lock.
+[clinic start generated code]*/
+
+static PyObject *
+_multiprocessing_SemLock___exit___impl(SemLockObject *self,
+                                       PyObject *exc_type,
+                                       PyObject *exc_value, PyObject *exc_tb)
+/*[clinic end generated code: output=3b37c1a9f8b91a03 input=7d644b64a89903f8]*/
+{
+    return _multiprocessing_SemLock_release_impl(self);
+}
+
+static int
+semlock_traverse(SemLockObject *s, visitproc visit, void *arg)
+{
+    Py_VISIT(Py_TYPE(s));
+    return 0;
+}
+
+/*
+ * Semaphore methods
+ */
+
+static PyMethodDef semlock_methods[] = {
+    _MULTIPROCESSING_SEMLOCK_ACQUIRE_METHODDEF
+    _MULTIPROCESSING_SEMLOCK_RELEASE_METHODDEF
+    _MULTIPROCESSING_SEMLOCK___ENTER___METHODDEF
+    _MULTIPROCESSING_SEMLOCK___EXIT___METHODDEF
+    _MULTIPROCESSING_SEMLOCK__COUNT_METHODDEF
+    _MULTIPROCESSING_SEMLOCK__IS_MINE_METHODDEF
+    _MULTIPROCESSING_SEMLOCK__GET_VALUE_METHODDEF
+    _MULTIPROCESSING_SEMLOCK__IS_ZERO_METHODDEF
+    _MULTIPROCESSING_SEMLOCK__REBUILD_METHODDEF
+    _MULTIPROCESSING_SEMLOCK__AFTER_FORK_METHODDEF
+    {NULL}
+};
+
+/*
+ * Member table
+ */
+
+static PyMemberDef semlock_members[] = {
+    {"handle", T_SEM_HANDLE, offsetof(SemLockObject, handle), READONLY,
+     ""},
+    {"kind", T_INT, offsetof(SemLockObject, kind), READONLY,
+     ""},
+    {"maxvalue", T_INT, offsetof(SemLockObject, maxvalue), READONLY,
+     ""},
+    {"name", T_STRING, offsetof(SemLockObject, name), READONLY,
+     ""},
+    {NULL}
+};
+
+/*
+ * Semaphore type
+ */
+
+static PyType_Slot _PyMp_SemLockType_slots[] = {
+    {Py_tp_dealloc, semlock_dealloc},
+    {Py_tp_getattro, PyObject_GenericGetAttr},
+    {Py_tp_setattro, PyObject_GenericSetAttr},
+    {Py_tp_methods, semlock_methods},
+    {Py_tp_members, semlock_members},
+    {Py_tp_alloc, PyType_GenericAlloc},
+    {Py_tp_new, _multiprocessing_SemLock},
+    {Py_tp_traverse, semlock_traverse},
+    {Py_tp_free, PyObject_GC_Del},
+    {Py_tp_doc, (void *)PyDoc_STR("Semaphore/Mutex type")},
+    {0, 0},
+};
+
+PyType_Spec _PyMp_SemLockType_spec = {
+    .name = "_multiprocessing.SemLock",
+    .basicsize = sizeof(SemLockObject),
+    .flags = (Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
+              Py_TPFLAGS_HAVE_GC | Py_TPFLAGS_IMMUTABLETYPE),
+    .slots = _PyMp_SemLockType_slots,
+};
+
+/*
+ * Function to unlink semaphore names
+ */
+
+PyObject *
+_PyMp_sem_unlink(const char *name)
+{
+    if (SEM_UNLINK(name) < 0) {
+        _PyMp_SetError(NULL, MP_STANDARD_ERROR);
+        return NULL;
+    }
+
+    Py_RETURN_NONE;
+}
+
+#endif // HAVE_MP_SEMAPHORE