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1 /*
2  * A type which wraps a semaphore
3  *
4  * semaphore.c
5  *
6  * Copyright (c) 2006-2008, R Oudkerk
7  * Licensed to PSF under a Contributor Agreement.
8  */
9 
10 #include "multiprocessing.h"
11 
12 enum { RECURSIVE_MUTEX, SEMAPHORE };
13 
14 typedef struct {
15     PyObject_HEAD
16     SEM_HANDLE handle;
17     unsigned long last_tid;
18     int count;
19     int maxvalue;
20     int kind;
21     char *name;
22 } SemLockObject;
23 
24 /*[python input]
25 class SEM_HANDLE_converter(CConverter):
26     type = "SEM_HANDLE"
27     format_unit = '"F_SEM_HANDLE"'
28 
29 [python start generated code]*/
30 /*[python end generated code: output=da39a3ee5e6b4b0d input=3e0ad43e482d8716]*/
31 
32 /*[clinic input]
33 module _multiprocessing
34 class _multiprocessing.SemLock "SemLockObject *" "&_PyMp_SemLockType"
35 [clinic start generated code]*/
36 /*[clinic end generated code: output=da39a3ee5e6b4b0d input=935fb41b7d032599]*/
37 
38 #include "clinic/semaphore.c.h"
39 
40 #define ISMINE(o) (o->count > 0 && PyThread_get_thread_ident() == o->last_tid)
41 
42 
43 #ifdef MS_WINDOWS
44 
45 /*
46  * Windows definitions
47  */
48 
49 #define SEM_FAILED NULL
50 
51 #define SEM_CLEAR_ERROR() SetLastError(0)
52 #define SEM_GET_LAST_ERROR() GetLastError()
53 #define SEM_CREATE(name, val, max) CreateSemaphore(NULL, val, max, NULL)
54 #define SEM_CLOSE(sem) (CloseHandle(sem) ? 0 : -1)
55 #define SEM_GETVALUE(sem, pval) _GetSemaphoreValue(sem, pval)
56 #define SEM_UNLINK(name) 0
57 
58 static int
_GetSemaphoreValue(HANDLE handle,long * value)59 _GetSemaphoreValue(HANDLE handle, long *value)
60 {
61     long previous;
62 
63     switch (WaitForSingleObjectEx(handle, 0, FALSE)) {
64     case WAIT_OBJECT_0:
65         if (!ReleaseSemaphore(handle, 1, &previous))
66             return MP_STANDARD_ERROR;
67         *value = previous + 1;
68         return 0;
69     case WAIT_TIMEOUT:
70         *value = 0;
71         return 0;
72     default:
73         return MP_STANDARD_ERROR;
74     }
75 }
76 
77 /*[clinic input]
78 _multiprocessing.SemLock.acquire
79 
80     block as blocking: bool(accept={int}) = True
81     timeout as timeout_obj: object = None
82 
83 Acquire the semaphore/lock.
84 [clinic start generated code]*/
85 
86 static PyObject *
_multiprocessing_SemLock_acquire_impl(SemLockObject * self,int blocking,PyObject * timeout_obj)87 _multiprocessing_SemLock_acquire_impl(SemLockObject *self, int blocking,
88                                       PyObject *timeout_obj)
89 /*[clinic end generated code: output=f9998f0b6b0b0872 input=86f05662cf753eb4]*/
90 {
91     double timeout;
92     DWORD res, full_msecs, nhandles;
93     HANDLE handles[2], sigint_event;
94 
95     /* calculate timeout */
96     if (!blocking) {
97         full_msecs = 0;
98     } else if (timeout_obj == Py_None) {
99         full_msecs = INFINITE;
100     } else {
101         timeout = PyFloat_AsDouble(timeout_obj);
102         if (PyErr_Occurred())
103             return NULL;
104         timeout *= 1000.0;      /* convert to millisecs */
105         if (timeout < 0.0) {
106             timeout = 0.0;
107         } else if (timeout >= 0.5 * INFINITE) { /* 25 days */
108             PyErr_SetString(PyExc_OverflowError,
109                             "timeout is too large");
110             return NULL;
111         }
112         full_msecs = (DWORD)(timeout + 0.5);
113     }
114 
115     /* check whether we already own the lock */
116     if (self->kind == RECURSIVE_MUTEX && ISMINE(self)) {
117         ++self->count;
118         Py_RETURN_TRUE;
119     }
120 
121     /* check whether we can acquire without releasing the GIL and blocking */
122     if (WaitForSingleObjectEx(self->handle, 0, FALSE) == WAIT_OBJECT_0) {
123         self->last_tid = GetCurrentThreadId();
124         ++self->count;
125         Py_RETURN_TRUE;
126     }
127 
128     /* prepare list of handles */
129     nhandles = 0;
130     handles[nhandles++] = self->handle;
131     if (_PyOS_IsMainThread()) {
132         sigint_event = _PyOS_SigintEvent();
133         assert(sigint_event != NULL);
134         handles[nhandles++] = sigint_event;
135     }
136     else {
137         sigint_event = NULL;
138     }
139 
140     /* do the wait */
141     Py_BEGIN_ALLOW_THREADS
142     if (sigint_event != NULL)
143         ResetEvent(sigint_event);
144     res = WaitForMultipleObjectsEx(nhandles, handles, FALSE, full_msecs, FALSE);
145     Py_END_ALLOW_THREADS
146 
147     /* handle result */
148     switch (res) {
149     case WAIT_TIMEOUT:
150         Py_RETURN_FALSE;
151     case WAIT_OBJECT_0 + 0:
152         self->last_tid = GetCurrentThreadId();
153         ++self->count;
154         Py_RETURN_TRUE;
155     case WAIT_OBJECT_0 + 1:
156         errno = EINTR;
157         return PyErr_SetFromErrno(PyExc_OSError);
158     case WAIT_FAILED:
159         return PyErr_SetFromWindowsErr(0);
160     default:
161         PyErr_Format(PyExc_RuntimeError, "WaitForSingleObject() or "
162                      "WaitForMultipleObjects() gave unrecognized "
163                      "value %u", res);
164         return NULL;
165     }
166 }
167 
168 /*[clinic input]
169 _multiprocessing.SemLock.release
170 
171 Release the semaphore/lock.
172 [clinic start generated code]*/
173 
174 static PyObject *
_multiprocessing_SemLock_release_impl(SemLockObject * self)175 _multiprocessing_SemLock_release_impl(SemLockObject *self)
176 /*[clinic end generated code: output=b22f53ba96b0d1db input=ba7e63a961885d3d]*/
177 {
178     if (self->kind == RECURSIVE_MUTEX) {
179         if (!ISMINE(self)) {
180             PyErr_SetString(PyExc_AssertionError, "attempt to "
181                             "release recursive lock not owned "
182                             "by thread");
183             return NULL;
184         }
185         if (self->count > 1) {
186             --self->count;
187             Py_RETURN_NONE;
188         }
189         assert(self->count == 1);
190     }
191 
192     if (!ReleaseSemaphore(self->handle, 1, NULL)) {
193         if (GetLastError() == ERROR_TOO_MANY_POSTS) {
194             PyErr_SetString(PyExc_ValueError, "semaphore or lock "
195                             "released too many times");
196             return NULL;
197         } else {
198             return PyErr_SetFromWindowsErr(0);
199         }
200     }
201 
202     --self->count;
203     Py_RETURN_NONE;
204 }
205 
206 #else /* !MS_WINDOWS */
207 
208 /*
209  * Unix definitions
210  */
211 
212 #define SEM_CLEAR_ERROR()
213 #define SEM_GET_LAST_ERROR() 0
214 #define SEM_CREATE(name, val, max) sem_open(name, O_CREAT | O_EXCL, 0600, val)
215 #define SEM_CLOSE(sem) sem_close(sem)
216 #define SEM_GETVALUE(sem, pval) sem_getvalue(sem, pval)
217 #define SEM_UNLINK(name) sem_unlink(name)
218 
219 /* OS X 10.4 defines SEM_FAILED as -1 instead of (sem_t *)-1;  this gives
220    compiler warnings, and (potentially) undefined behaviour. */
221 #ifdef __APPLE__
222 #  undef SEM_FAILED
223 #  define SEM_FAILED ((sem_t *)-1)
224 #endif
225 
226 #ifndef HAVE_SEM_UNLINK
227 #  define sem_unlink(name) 0
228 #endif
229 
230 #ifndef HAVE_SEM_TIMEDWAIT
231 #  define sem_timedwait(sem,deadline) sem_timedwait_save(sem,deadline,_save)
232 
233 static int
sem_timedwait_save(sem_t * sem,struct timespec * deadline,PyThreadState * _save)234 sem_timedwait_save(sem_t *sem, struct timespec *deadline, PyThreadState *_save)
235 {
236     int res;
237     unsigned long delay, difference;
238     struct timeval now, tvdeadline, tvdelay;
239 
240     errno = 0;
241     tvdeadline.tv_sec = deadline->tv_sec;
242     tvdeadline.tv_usec = deadline->tv_nsec / 1000;
243 
244     for (delay = 0 ; ; delay += 1000) {
245         /* poll */
246         if (sem_trywait(sem) == 0)
247             return 0;
248         else if (errno != EAGAIN)
249             return MP_STANDARD_ERROR;
250 
251         /* get current time */
252         if (gettimeofday(&now, NULL) < 0)
253             return MP_STANDARD_ERROR;
254 
255         /* check for timeout */
256         if (tvdeadline.tv_sec < now.tv_sec ||
257             (tvdeadline.tv_sec == now.tv_sec &&
258              tvdeadline.tv_usec <= now.tv_usec)) {
259             errno = ETIMEDOUT;
260             return MP_STANDARD_ERROR;
261         }
262 
263         /* calculate how much time is left */
264         difference = (tvdeadline.tv_sec - now.tv_sec) * 1000000 +
265             (tvdeadline.tv_usec - now.tv_usec);
266 
267         /* check delay not too long -- maximum is 20 msecs */
268         if (delay > 20000)
269             delay = 20000;
270         if (delay > difference)
271             delay = difference;
272 
273         /* sleep */
274         tvdelay.tv_sec = delay / 1000000;
275         tvdelay.tv_usec = delay % 1000000;
276         if (select(0, NULL, NULL, NULL, &tvdelay) < 0)
277             return MP_STANDARD_ERROR;
278 
279         /* check for signals */
280         Py_BLOCK_THREADS
281         res = PyErr_CheckSignals();
282         Py_UNBLOCK_THREADS
283 
284         if (res) {
285             errno = EINTR;
286             return MP_EXCEPTION_HAS_BEEN_SET;
287         }
288     }
289 }
290 
291 #endif /* !HAVE_SEM_TIMEDWAIT */
292 
293 /*[clinic input]
294 _multiprocessing.SemLock.acquire
295 
296     block as blocking: bool(accept={int}) = True
297     timeout as timeout_obj: object = None
298 
299 Acquire the semaphore/lock.
300 [clinic start generated code]*/
301 
302 static PyObject *
_multiprocessing_SemLock_acquire_impl(SemLockObject * self,int blocking,PyObject * timeout_obj)303 _multiprocessing_SemLock_acquire_impl(SemLockObject *self, int blocking,
304                                       PyObject *timeout_obj)
305 /*[clinic end generated code: output=f9998f0b6b0b0872 input=86f05662cf753eb4]*/
306 {
307     int res, err = 0;
308     struct timespec deadline = {0};
309 
310     if (self->kind == RECURSIVE_MUTEX && ISMINE(self)) {
311         ++self->count;
312         Py_RETURN_TRUE;
313     }
314 
315     int use_deadline = (timeout_obj != Py_None);
316     if (use_deadline) {
317         double timeout = PyFloat_AsDouble(timeout_obj);
318         if (PyErr_Occurred()) {
319             return NULL;
320         }
321         if (timeout < 0.0) {
322             timeout = 0.0;
323         }
324 
325         struct timeval now;
326         if (gettimeofday(&now, NULL) < 0) {
327             PyErr_SetFromErrno(PyExc_OSError);
328             return NULL;
329         }
330         long sec = (long) timeout;
331         long nsec = (long) (1e9 * (timeout - sec) + 0.5);
332         deadline.tv_sec = now.tv_sec + sec;
333         deadline.tv_nsec = now.tv_usec * 1000 + nsec;
334         deadline.tv_sec += (deadline.tv_nsec / 1000000000);
335         deadline.tv_nsec %= 1000000000;
336     }
337 
338     /* Check whether we can acquire without releasing the GIL and blocking */
339     do {
340         res = sem_trywait(self->handle);
341         err = errno;
342     } while (res < 0 && errno == EINTR && !PyErr_CheckSignals());
343     errno = err;
344 
345     if (res < 0 && errno == EAGAIN && blocking) {
346         /* Couldn't acquire immediately, need to block */
347         do {
348             Py_BEGIN_ALLOW_THREADS
349             if (!use_deadline) {
350                 res = sem_wait(self->handle);
351             }
352             else {
353                 res = sem_timedwait(self->handle, &deadline);
354             }
355             Py_END_ALLOW_THREADS
356             err = errno;
357             if (res == MP_EXCEPTION_HAS_BEEN_SET)
358                 break;
359         } while (res < 0 && errno == EINTR && !PyErr_CheckSignals());
360     }
361 
362     if (res < 0) {
363         errno = err;
364         if (errno == EAGAIN || errno == ETIMEDOUT)
365             Py_RETURN_FALSE;
366         else if (errno == EINTR)
367             return NULL;
368         else
369             return PyErr_SetFromErrno(PyExc_OSError);
370     }
371 
372     ++self->count;
373     self->last_tid = PyThread_get_thread_ident();
374 
375     Py_RETURN_TRUE;
376 }
377 
378 /*[clinic input]
379 _multiprocessing.SemLock.release
380 
381 Release the semaphore/lock.
382 [clinic start generated code]*/
383 
384 static PyObject *
_multiprocessing_SemLock_release_impl(SemLockObject * self)385 _multiprocessing_SemLock_release_impl(SemLockObject *self)
386 /*[clinic end generated code: output=b22f53ba96b0d1db input=ba7e63a961885d3d]*/
387 {
388     if (self->kind == RECURSIVE_MUTEX) {
389         if (!ISMINE(self)) {
390             PyErr_SetString(PyExc_AssertionError, "attempt to "
391                             "release recursive lock not owned "
392                             "by thread");
393             return NULL;
394         }
395         if (self->count > 1) {
396             --self->count;
397             Py_RETURN_NONE;
398         }
399         assert(self->count == 1);
400     } else {
401 #ifdef HAVE_BROKEN_SEM_GETVALUE
402         /* We will only check properly the maxvalue == 1 case */
403         if (self->maxvalue == 1) {
404             /* make sure that already locked */
405             if (sem_trywait(self->handle) < 0) {
406                 if (errno != EAGAIN) {
407                     PyErr_SetFromErrno(PyExc_OSError);
408                     return NULL;
409                 }
410                 /* it is already locked as expected */
411             } else {
412                 /* it was not locked so undo wait and raise  */
413                 if (sem_post(self->handle) < 0) {
414                     PyErr_SetFromErrno(PyExc_OSError);
415                     return NULL;
416                 }
417                 PyErr_SetString(PyExc_ValueError, "semaphore "
418                                 "or lock released too many "
419                                 "times");
420                 return NULL;
421             }
422         }
423 #else
424         int sval;
425 
426         /* This check is not an absolute guarantee that the semaphore
427            does not rise above maxvalue. */
428         if (sem_getvalue(self->handle, &sval) < 0) {
429             return PyErr_SetFromErrno(PyExc_OSError);
430         } else if (sval >= self->maxvalue) {
431             PyErr_SetString(PyExc_ValueError, "semaphore or lock "
432                             "released too many times");
433             return NULL;
434         }
435 #endif
436     }
437 
438     if (sem_post(self->handle) < 0)
439         return PyErr_SetFromErrno(PyExc_OSError);
440 
441     --self->count;
442     Py_RETURN_NONE;
443 }
444 
445 #endif /* !MS_WINDOWS */
446 
447 /*
448  * All platforms
449  */
450 
451 static PyObject *
newsemlockobject(PyTypeObject * type,SEM_HANDLE handle,int kind,int maxvalue,char * name)452 newsemlockobject(PyTypeObject *type, SEM_HANDLE handle, int kind, int maxvalue,
453                  char *name)
454 {
455     SemLockObject *self;
456 
457     self = PyObject_New(SemLockObject, type);
458     if (!self)
459         return NULL;
460     self->handle = handle;
461     self->kind = kind;
462     self->count = 0;
463     self->last_tid = 0;
464     self->maxvalue = maxvalue;
465     self->name = name;
466     return (PyObject*)self;
467 }
468 
469 /*[clinic input]
470 @classmethod
471 _multiprocessing.SemLock.__new__
472 
473     kind: int
474     value: int
475     maxvalue: int
476     name: str
477     unlink: bool(accept={int})
478 
479 [clinic start generated code]*/
480 
481 static PyObject *
_multiprocessing_SemLock_impl(PyTypeObject * type,int kind,int value,int maxvalue,const char * name,int unlink)482 _multiprocessing_SemLock_impl(PyTypeObject *type, int kind, int value,
483                               int maxvalue, const char *name, int unlink)
484 /*[clinic end generated code: output=30727e38f5f7577a input=b378c3ee27d3a0fa]*/
485 {
486     SEM_HANDLE handle = SEM_FAILED;
487     PyObject *result;
488     char *name_copy = NULL;
489 
490     if (kind != RECURSIVE_MUTEX && kind != SEMAPHORE) {
491         PyErr_SetString(PyExc_ValueError, "unrecognized kind");
492         return NULL;
493     }
494 
495     if (!unlink) {
496         name_copy = PyMem_Malloc(strlen(name) + 1);
497         if (name_copy == NULL) {
498             return PyErr_NoMemory();
499         }
500         strcpy(name_copy, name);
501     }
502 
503     SEM_CLEAR_ERROR();
504     handle = SEM_CREATE(name, value, maxvalue);
505     /* On Windows we should fail if GetLastError()==ERROR_ALREADY_EXISTS */
506     if (handle == SEM_FAILED || SEM_GET_LAST_ERROR() != 0)
507         goto failure;
508 
509     if (unlink && SEM_UNLINK(name) < 0)
510         goto failure;
511 
512     result = newsemlockobject(type, handle, kind, maxvalue, name_copy);
513     if (!result)
514         goto failure;
515 
516     return result;
517 
518   failure:
519     if (handle != SEM_FAILED)
520         SEM_CLOSE(handle);
521     PyMem_Free(name_copy);
522     if (!PyErr_Occurred()) {
523         _PyMp_SetError(NULL, MP_STANDARD_ERROR);
524     }
525     return NULL;
526 }
527 
528 /*[clinic input]
529 @classmethod
530 _multiprocessing.SemLock._rebuild
531 
532     handle: SEM_HANDLE
533     kind: int
534     maxvalue: int
535     name: str(accept={str, NoneType})
536     /
537 
538 [clinic start generated code]*/
539 
540 static PyObject *
_multiprocessing_SemLock__rebuild_impl(PyTypeObject * type,SEM_HANDLE handle,int kind,int maxvalue,const char * name)541 _multiprocessing_SemLock__rebuild_impl(PyTypeObject *type, SEM_HANDLE handle,
542                                        int kind, int maxvalue,
543                                        const char *name)
544 /*[clinic end generated code: output=2aaee14f063f3bd9 input=f7040492ac6d9962]*/
545 {
546     char *name_copy = NULL;
547 
548     if (name != NULL) {
549         name_copy = PyMem_Malloc(strlen(name) + 1);
550         if (name_copy == NULL)
551             return PyErr_NoMemory();
552         strcpy(name_copy, name);
553     }
554 
555 #ifndef MS_WINDOWS
556     if (name != NULL) {
557         handle = sem_open(name, 0);
558         if (handle == SEM_FAILED) {
559             PyMem_Free(name_copy);
560             return PyErr_SetFromErrno(PyExc_OSError);
561         }
562     }
563 #endif
564 
565     return newsemlockobject(type, handle, kind, maxvalue, name_copy);
566 }
567 
568 static void
semlock_dealloc(SemLockObject * self)569 semlock_dealloc(SemLockObject* self)
570 {
571     if (self->handle != SEM_FAILED)
572         SEM_CLOSE(self->handle);
573     PyMem_Free(self->name);
574     PyObject_Free(self);
575 }
576 
577 /*[clinic input]
578 _multiprocessing.SemLock._count
579 
580 Num of `acquire()`s minus num of `release()`s for this process.
581 [clinic start generated code]*/
582 
583 static PyObject *
_multiprocessing_SemLock__count_impl(SemLockObject * self)584 _multiprocessing_SemLock__count_impl(SemLockObject *self)
585 /*[clinic end generated code: output=5ba8213900e517bb input=36fc59b1cd1025ab]*/
586 {
587     return PyLong_FromLong((long)self->count);
588 }
589 
590 /*[clinic input]
591 _multiprocessing.SemLock._is_mine
592 
593 Whether the lock is owned by this thread.
594 [clinic start generated code]*/
595 
596 static PyObject *
_multiprocessing_SemLock__is_mine_impl(SemLockObject * self)597 _multiprocessing_SemLock__is_mine_impl(SemLockObject *self)
598 /*[clinic end generated code: output=92dc98863f4303be input=a96664cb2f0093ba]*/
599 {
600     /* only makes sense for a lock */
601     return PyBool_FromLong(ISMINE(self));
602 }
603 
604 /*[clinic input]
605 _multiprocessing.SemLock._get_value
606 
607 Get the value of the semaphore.
608 [clinic start generated code]*/
609 
610 static PyObject *
_multiprocessing_SemLock__get_value_impl(SemLockObject * self)611 _multiprocessing_SemLock__get_value_impl(SemLockObject *self)
612 /*[clinic end generated code: output=64bc1b89bda05e36 input=cb10f9a769836203]*/
613 {
614 #ifdef HAVE_BROKEN_SEM_GETVALUE
615     PyErr_SetNone(PyExc_NotImplementedError);
616     return NULL;
617 #else
618     int sval;
619     if (SEM_GETVALUE(self->handle, &sval) < 0)
620         return _PyMp_SetError(NULL, MP_STANDARD_ERROR);
621     /* some posix implementations use negative numbers to indicate
622        the number of waiting threads */
623     if (sval < 0)
624         sval = 0;
625     return PyLong_FromLong((long)sval);
626 #endif
627 }
628 
629 /*[clinic input]
630 _multiprocessing.SemLock._is_zero
631 
632 Return whether semaphore has value zero.
633 [clinic start generated code]*/
634 
635 static PyObject *
_multiprocessing_SemLock__is_zero_impl(SemLockObject * self)636 _multiprocessing_SemLock__is_zero_impl(SemLockObject *self)
637 /*[clinic end generated code: output=815d4c878c806ed7 input=294a446418d31347]*/
638 {
639 #ifdef HAVE_BROKEN_SEM_GETVALUE
640     if (sem_trywait(self->handle) < 0) {
641         if (errno == EAGAIN)
642             Py_RETURN_TRUE;
643         return _PyMp_SetError(NULL, MP_STANDARD_ERROR);
644     } else {
645         if (sem_post(self->handle) < 0)
646             return _PyMp_SetError(NULL, MP_STANDARD_ERROR);
647         Py_RETURN_FALSE;
648     }
649 #else
650     int sval;
651     if (SEM_GETVALUE(self->handle, &sval) < 0)
652         return _PyMp_SetError(NULL, MP_STANDARD_ERROR);
653     return PyBool_FromLong((long)sval == 0);
654 #endif
655 }
656 
657 /*[clinic input]
658 _multiprocessing.SemLock._after_fork
659 
660 Rezero the net acquisition count after fork().
661 [clinic start generated code]*/
662 
663 static PyObject *
_multiprocessing_SemLock__after_fork_impl(SemLockObject * self)664 _multiprocessing_SemLock__after_fork_impl(SemLockObject *self)
665 /*[clinic end generated code: output=718bb27914c6a6c1 input=190991008a76621e]*/
666 {
667     self->count = 0;
668     Py_RETURN_NONE;
669 }
670 
671 /*[clinic input]
672 _multiprocessing.SemLock.__enter__
673 
674 Enter the semaphore/lock.
675 [clinic start generated code]*/
676 
677 static PyObject *
_multiprocessing_SemLock___enter___impl(SemLockObject * self)678 _multiprocessing_SemLock___enter___impl(SemLockObject *self)
679 /*[clinic end generated code: output=beeb2f07c858511f input=c5e27d594284690b]*/
680 {
681     return _multiprocessing_SemLock_acquire_impl(self, 1, Py_None);
682 }
683 
684 /*[clinic input]
685 _multiprocessing.SemLock.__exit__
686 
687     exc_type: object = None
688     exc_value: object = None
689     exc_tb: object = None
690     /
691 
692 Exit the semaphore/lock.
693 [clinic start generated code]*/
694 
695 static PyObject *
_multiprocessing_SemLock___exit___impl(SemLockObject * self,PyObject * exc_type,PyObject * exc_value,PyObject * exc_tb)696 _multiprocessing_SemLock___exit___impl(SemLockObject *self,
697                                        PyObject *exc_type,
698                                        PyObject *exc_value, PyObject *exc_tb)
699 /*[clinic end generated code: output=3b37c1a9f8b91a03 input=7d644b64a89903f8]*/
700 {
701     return _multiprocessing_SemLock_release_impl(self);
702 }
703 
704 /*
705  * Semaphore methods
706  */
707 
708 static PyMethodDef semlock_methods[] = {
709     _MULTIPROCESSING_SEMLOCK_ACQUIRE_METHODDEF
710     _MULTIPROCESSING_SEMLOCK_RELEASE_METHODDEF
711     _MULTIPROCESSING_SEMLOCK___ENTER___METHODDEF
712     _MULTIPROCESSING_SEMLOCK___EXIT___METHODDEF
713     _MULTIPROCESSING_SEMLOCK__COUNT_METHODDEF
714     _MULTIPROCESSING_SEMLOCK__IS_MINE_METHODDEF
715     _MULTIPROCESSING_SEMLOCK__GET_VALUE_METHODDEF
716     _MULTIPROCESSING_SEMLOCK__IS_ZERO_METHODDEF
717     _MULTIPROCESSING_SEMLOCK__REBUILD_METHODDEF
718     _MULTIPROCESSING_SEMLOCK__AFTER_FORK_METHODDEF
719     {NULL}
720 };
721 
722 /*
723  * Member table
724  */
725 
726 static PyMemberDef semlock_members[] = {
727     {"handle", T_SEM_HANDLE, offsetof(SemLockObject, handle), READONLY,
728      ""},
729     {"kind", T_INT, offsetof(SemLockObject, kind), READONLY,
730      ""},
731     {"maxvalue", T_INT, offsetof(SemLockObject, maxvalue), READONLY,
732      ""},
733     {"name", T_STRING, offsetof(SemLockObject, name), READONLY,
734      ""},
735     {NULL}
736 };
737 
738 /*
739  * Semaphore type
740  */
741 
742 PyTypeObject _PyMp_SemLockType = {
743     PyVarObject_HEAD_INIT(NULL, 0)
744     /* tp_name           */ "_multiprocessing.SemLock",
745     /* tp_basicsize      */ sizeof(SemLockObject),
746     /* tp_itemsize       */ 0,
747     /* tp_dealloc        */ (destructor)semlock_dealloc,
748     /* tp_vectorcall_offset */ 0,
749     /* tp_getattr        */ 0,
750     /* tp_setattr        */ 0,
751     /* tp_as_async       */ 0,
752     /* tp_repr           */ 0,
753     /* tp_as_number      */ 0,
754     /* tp_as_sequence    */ 0,
755     /* tp_as_mapping     */ 0,
756     /* tp_hash           */ 0,
757     /* tp_call           */ 0,
758     /* tp_str            */ 0,
759     /* tp_getattro       */ 0,
760     /* tp_setattro       */ 0,
761     /* tp_as_buffer      */ 0,
762     /* tp_flags          */ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
763     /* tp_doc            */ "Semaphore/Mutex type",
764     /* tp_traverse       */ 0,
765     /* tp_clear          */ 0,
766     /* tp_richcompare    */ 0,
767     /* tp_weaklistoffset */ 0,
768     /* tp_iter           */ 0,
769     /* tp_iternext       */ 0,
770     /* tp_methods        */ semlock_methods,
771     /* tp_members        */ semlock_members,
772     /* tp_getset         */ 0,
773     /* tp_base           */ 0,
774     /* tp_dict           */ 0,
775     /* tp_descr_get      */ 0,
776     /* tp_descr_set      */ 0,
777     /* tp_dictoffset     */ 0,
778     /* tp_init           */ 0,
779     /* tp_alloc          */ 0,
780     /* tp_new            */ _multiprocessing_SemLock,
781 };
782 
783 /*
784  * Function to unlink semaphore names
785  */
786 
787 PyObject *
_PyMp_sem_unlink(const char * name)788 _PyMp_sem_unlink(const char *name)
789 {
790     if (SEM_UNLINK(name) < 0) {
791         _PyMp_SetError(NULL, MP_STANDARD_ERROR);
792         return NULL;
793     }
794 
795     Py_RETURN_NONE;
796 }
797