1
2 /* This code implemented by Dag.Gruneau@elsa.preseco.comm.se */
3 /* Fast NonRecursiveMutex support by Yakov Markovitch, markovitch@iso.ru */
4 /* Eliminated some memory leaks, gsw@agere.com */
5
6 #include <windows.h>
7 #include <limits.h>
8 #ifdef HAVE_PROCESS_H
9 #include <process.h>
10 #endif
11
12 /* options */
13 #ifndef _PY_USE_CV_LOCKS
14 #define _PY_USE_CV_LOCKS 1 /* use locks based on cond vars */
15 #endif
16
17 /* Now, define a non-recursive mutex using either condition variables
18 * and critical sections (fast) or using operating system mutexes
19 * (slow)
20 */
21
22 #if _PY_USE_CV_LOCKS
23
24 #include "condvar.h"
25
26 typedef struct _NRMUTEX
27 {
28 PyMUTEX_T cs;
29 PyCOND_T cv;
30 int locked;
31 } NRMUTEX;
32 typedef NRMUTEX *PNRMUTEX;
33
34 PNRMUTEX
AllocNonRecursiveMutex()35 AllocNonRecursiveMutex()
36 {
37 PNRMUTEX m = (PNRMUTEX)PyMem_RawMalloc(sizeof(NRMUTEX));
38 if (!m)
39 return NULL;
40 if (PyCOND_INIT(&m->cv))
41 goto fail;
42 if (PyMUTEX_INIT(&m->cs)) {
43 PyCOND_FINI(&m->cv);
44 goto fail;
45 }
46 m->locked = 0;
47 return m;
48 fail:
49 PyMem_RawFree(m);
50 return NULL;
51 }
52
53 VOID
FreeNonRecursiveMutex(PNRMUTEX mutex)54 FreeNonRecursiveMutex(PNRMUTEX mutex)
55 {
56 if (mutex) {
57 PyCOND_FINI(&mutex->cv);
58 PyMUTEX_FINI(&mutex->cs);
59 PyMem_RawFree(mutex);
60 }
61 }
62
63 DWORD
EnterNonRecursiveMutex(PNRMUTEX mutex,DWORD milliseconds)64 EnterNonRecursiveMutex(PNRMUTEX mutex, DWORD milliseconds)
65 {
66 DWORD result = WAIT_OBJECT_0;
67 if (PyMUTEX_LOCK(&mutex->cs))
68 return WAIT_FAILED;
69 if (milliseconds == INFINITE) {
70 while (mutex->locked) {
71 if (PyCOND_WAIT(&mutex->cv, &mutex->cs)) {
72 result = WAIT_FAILED;
73 break;
74 }
75 }
76 } else if (milliseconds != 0) {
77 /* wait at least until the target */
78 ULONGLONG now, target = GetTickCount64() + milliseconds;
79 while (mutex->locked) {
80 if (PyCOND_TIMEDWAIT(&mutex->cv, &mutex->cs, (long long)milliseconds*1000) < 0) {
81 result = WAIT_FAILED;
82 break;
83 }
84 now = GetTickCount64();
85 if (target <= now)
86 break;
87 milliseconds = (DWORD)(target-now);
88 }
89 }
90 if (!mutex->locked) {
91 mutex->locked = 1;
92 result = WAIT_OBJECT_0;
93 } else if (result == WAIT_OBJECT_0)
94 result = WAIT_TIMEOUT;
95 /* else, it is WAIT_FAILED */
96 PyMUTEX_UNLOCK(&mutex->cs); /* must ignore result here */
97 return result;
98 }
99
100 BOOL
LeaveNonRecursiveMutex(PNRMUTEX mutex)101 LeaveNonRecursiveMutex(PNRMUTEX mutex)
102 {
103 BOOL result;
104 if (PyMUTEX_LOCK(&mutex->cs))
105 return FALSE;
106 mutex->locked = 0;
107 /* condvar APIs return 0 on success. We need to return TRUE on success. */
108 result = !PyCOND_SIGNAL(&mutex->cv);
109 PyMUTEX_UNLOCK(&mutex->cs);
110 return result;
111 }
112
113 #else /* if ! _PY_USE_CV_LOCKS */
114
115 /* NR-locks based on a kernel mutex */
116 #define PNRMUTEX HANDLE
117
118 PNRMUTEX
AllocNonRecursiveMutex()119 AllocNonRecursiveMutex()
120 {
121 return CreateSemaphore(NULL, 1, 1, NULL);
122 }
123
124 VOID
FreeNonRecursiveMutex(PNRMUTEX mutex)125 FreeNonRecursiveMutex(PNRMUTEX mutex)
126 {
127 /* No in-use check */
128 CloseHandle(mutex);
129 }
130
131 DWORD
EnterNonRecursiveMutex(PNRMUTEX mutex,DWORD milliseconds)132 EnterNonRecursiveMutex(PNRMUTEX mutex, DWORD milliseconds)
133 {
134 return WaitForSingleObjectEx(mutex, milliseconds, FALSE);
135 }
136
137 BOOL
LeaveNonRecursiveMutex(PNRMUTEX mutex)138 LeaveNonRecursiveMutex(PNRMUTEX mutex)
139 {
140 return ReleaseSemaphore(mutex, 1, NULL);
141 }
142 #endif /* _PY_USE_CV_LOCKS */
143
144 unsigned long PyThread_get_thread_ident(void);
145
146 #ifdef PY_HAVE_THREAD_NATIVE_ID
147 unsigned long PyThread_get_thread_native_id(void);
148 #endif
149
150 /*
151 * Initialization of the C package, should not be needed.
152 */
153 static void
PyThread__init_thread(void)154 PyThread__init_thread(void)
155 {
156 }
157
158 /*
159 * Thread support.
160 */
161
162 typedef struct {
163 void (*func)(void*);
164 void *arg;
165 } callobj;
166
167 /* thunker to call adapt between the function type used by the system's
168 thread start function and the internally used one. */
169 static unsigned __stdcall
bootstrap(void * call)170 bootstrap(void *call)
171 {
172 callobj *obj = (callobj*)call;
173 void (*func)(void*) = obj->func;
174 void *arg = obj->arg;
175 HeapFree(GetProcessHeap(), 0, obj);
176 func(arg);
177 return 0;
178 }
179
180 unsigned long
PyThread_start_new_thread(void (* func)(void *),void * arg)181 PyThread_start_new_thread(void (*func)(void *), void *arg)
182 {
183 HANDLE hThread;
184 unsigned threadID;
185 callobj *obj;
186
187 dprintf(("%lu: PyThread_start_new_thread called\n",
188 PyThread_get_thread_ident()));
189 if (!initialized)
190 PyThread_init_thread();
191
192 obj = (callobj*)HeapAlloc(GetProcessHeap(), 0, sizeof(*obj));
193 if (!obj)
194 return PYTHREAD_INVALID_THREAD_ID;
195 obj->func = func;
196 obj->arg = arg;
197 PyThreadState *tstate = _PyThreadState_GET();
198 size_t stacksize = tstate ? tstate->interp->pythread_stacksize : 0;
199 hThread = (HANDLE)_beginthreadex(0,
200 Py_SAFE_DOWNCAST(stacksize, Py_ssize_t, unsigned int),
201 bootstrap, obj,
202 0, &threadID);
203 if (hThread == 0) {
204 /* I've seen errno == EAGAIN here, which means "there are
205 * too many threads".
206 */
207 int e = errno;
208 dprintf(("%lu: PyThread_start_new_thread failed, errno %d\n",
209 PyThread_get_thread_ident(), e));
210 threadID = (unsigned)-1;
211 HeapFree(GetProcessHeap(), 0, obj);
212 }
213 else {
214 dprintf(("%lu: PyThread_start_new_thread succeeded: %p\n",
215 PyThread_get_thread_ident(), (void*)hThread));
216 CloseHandle(hThread);
217 }
218 return threadID;
219 }
220
221 /*
222 * Return the thread Id instead of a handle. The Id is said to uniquely identify the
223 * thread in the system
224 */
225 unsigned long
PyThread_get_thread_ident(void)226 PyThread_get_thread_ident(void)
227 {
228 if (!initialized)
229 PyThread_init_thread();
230
231 return GetCurrentThreadId();
232 }
233
234 #ifdef PY_HAVE_THREAD_NATIVE_ID
235 /*
236 * Return the native Thread ID (TID) of the calling thread.
237 * The native ID of a thread is valid and guaranteed to be unique system-wide
238 * from the time the thread is created until the thread has been terminated.
239 */
240 unsigned long
PyThread_get_thread_native_id(void)241 PyThread_get_thread_native_id(void)
242 {
243 if (!initialized) {
244 PyThread_init_thread();
245 }
246
247 DWORD native_id;
248 native_id = GetCurrentThreadId();
249 return (unsigned long) native_id;
250 }
251 #endif
252
253 void _Py_NO_RETURN
PyThread_exit_thread(void)254 PyThread_exit_thread(void)
255 {
256 dprintf(("%lu: PyThread_exit_thread called\n", PyThread_get_thread_ident()));
257 if (!initialized)
258 exit(0);
259 _endthreadex(0);
260 }
261
262 /*
263 * Lock support. It has to be implemented as semaphores.
264 * I [Dag] tried to implement it with mutex but I could find a way to
265 * tell whether a thread already own the lock or not.
266 */
267 PyThread_type_lock
PyThread_allocate_lock(void)268 PyThread_allocate_lock(void)
269 {
270 PNRMUTEX aLock;
271
272 dprintf(("PyThread_allocate_lock called\n"));
273 if (!initialized)
274 PyThread_init_thread();
275
276 aLock = AllocNonRecursiveMutex() ;
277
278 dprintf(("%lu: PyThread_allocate_lock() -> %p\n", PyThread_get_thread_ident(), aLock));
279
280 return (PyThread_type_lock) aLock;
281 }
282
283 void
PyThread_free_lock(PyThread_type_lock aLock)284 PyThread_free_lock(PyThread_type_lock aLock)
285 {
286 dprintf(("%lu: PyThread_free_lock(%p) called\n", PyThread_get_thread_ident(),aLock));
287
288 FreeNonRecursiveMutex(aLock) ;
289 }
290
291 /*
292 * Return 1 on success if the lock was acquired
293 *
294 * and 0 if the lock was not acquired. This means a 0 is returned
295 * if the lock has already been acquired by this thread!
296 */
297 PyLockStatus
PyThread_acquire_lock_timed(PyThread_type_lock aLock,PY_TIMEOUT_T microseconds,int intr_flag)298 PyThread_acquire_lock_timed(PyThread_type_lock aLock,
299 PY_TIMEOUT_T microseconds, int intr_flag)
300 {
301 /* Fow now, intr_flag does nothing on Windows, and lock acquires are
302 * uninterruptible. */
303 PyLockStatus success;
304 PY_TIMEOUT_T milliseconds;
305
306 if (microseconds >= 0) {
307 milliseconds = microseconds / 1000;
308 if (microseconds % 1000 > 0)
309 ++milliseconds;
310 if (milliseconds > PY_DWORD_MAX) {
311 Py_FatalError("Timeout larger than PY_TIMEOUT_MAX");
312 }
313 }
314 else {
315 milliseconds = INFINITE;
316 }
317
318 dprintf(("%lu: PyThread_acquire_lock_timed(%p, %lld) called\n",
319 PyThread_get_thread_ident(), aLock, microseconds));
320
321 if (aLock && EnterNonRecursiveMutex((PNRMUTEX)aLock,
322 (DWORD)milliseconds) == WAIT_OBJECT_0) {
323 success = PY_LOCK_ACQUIRED;
324 }
325 else {
326 success = PY_LOCK_FAILURE;
327 }
328
329 dprintf(("%lu: PyThread_acquire_lock(%p, %lld) -> %d\n",
330 PyThread_get_thread_ident(), aLock, microseconds, success));
331
332 return success;
333 }
334 int
PyThread_acquire_lock(PyThread_type_lock aLock,int waitflag)335 PyThread_acquire_lock(PyThread_type_lock aLock, int waitflag)
336 {
337 return PyThread_acquire_lock_timed(aLock, waitflag ? -1 : 0, 0);
338 }
339
340 void
PyThread_release_lock(PyThread_type_lock aLock)341 PyThread_release_lock(PyThread_type_lock aLock)
342 {
343 dprintf(("%lu: PyThread_release_lock(%p) called\n", PyThread_get_thread_ident(),aLock));
344
345 if (!(aLock && LeaveNonRecursiveMutex((PNRMUTEX) aLock)))
346 dprintf(("%lu: Could not PyThread_release_lock(%p) error: %ld\n", PyThread_get_thread_ident(), aLock, GetLastError()));
347 }
348
349 /* minimum/maximum thread stack sizes supported */
350 #define THREAD_MIN_STACKSIZE 0x8000 /* 32 KiB */
351 #define THREAD_MAX_STACKSIZE 0x10000000 /* 256 MiB */
352
353 /* set the thread stack size.
354 * Return 0 if size is valid, -1 otherwise.
355 */
356 static int
_pythread_nt_set_stacksize(size_t size)357 _pythread_nt_set_stacksize(size_t size)
358 {
359 /* set to default */
360 if (size == 0) {
361 _PyInterpreterState_GET_UNSAFE()->pythread_stacksize = 0;
362 return 0;
363 }
364
365 /* valid range? */
366 if (size >= THREAD_MIN_STACKSIZE && size < THREAD_MAX_STACKSIZE) {
367 _PyInterpreterState_GET_UNSAFE()->pythread_stacksize = size;
368 return 0;
369 }
370
371 return -1;
372 }
373
374 #define THREAD_SET_STACKSIZE(x) _pythread_nt_set_stacksize(x)
375
376
377 /* Thread Local Storage (TLS) API
378
379 This API is DEPRECATED since Python 3.7. See PEP 539 for details.
380 */
381
382 int
PyThread_create_key(void)383 PyThread_create_key(void)
384 {
385 DWORD result = TlsAlloc();
386 if (result == TLS_OUT_OF_INDEXES)
387 return -1;
388 return (int)result;
389 }
390
391 void
PyThread_delete_key(int key)392 PyThread_delete_key(int key)
393 {
394 TlsFree(key);
395 }
396
397 int
PyThread_set_key_value(int key,void * value)398 PyThread_set_key_value(int key, void *value)
399 {
400 BOOL ok = TlsSetValue(key, value);
401 return ok ? 0 : -1;
402 }
403
404 void *
PyThread_get_key_value(int key)405 PyThread_get_key_value(int key)
406 {
407 /* because TLS is used in the Py_END_ALLOW_THREAD macro,
408 * it is necessary to preserve the windows error state, because
409 * it is assumed to be preserved across the call to the macro.
410 * Ideally, the macro should be fixed, but it is simpler to
411 * do it here.
412 */
413 DWORD error = GetLastError();
414 void *result = TlsGetValue(key);
415 SetLastError(error);
416 return result;
417 }
418
419 void
PyThread_delete_key_value(int key)420 PyThread_delete_key_value(int key)
421 {
422 /* NULL is used as "key missing", and it is also the default
423 * given by TlsGetValue() if nothing has been set yet.
424 */
425 TlsSetValue(key, NULL);
426 }
427
428
429 /* reinitialization of TLS is not necessary after fork when using
430 * the native TLS functions. And forking isn't supported on Windows either.
431 */
432 void
PyThread_ReInitTLS(void)433 PyThread_ReInitTLS(void)
434 {
435 }
436
437
438 /* Thread Specific Storage (TSS) API
439
440 Platform-specific components of TSS API implementation.
441 */
442
443 int
PyThread_tss_create(Py_tss_t * key)444 PyThread_tss_create(Py_tss_t *key)
445 {
446 assert(key != NULL);
447 /* If the key has been created, function is silently skipped. */
448 if (key->_is_initialized) {
449 return 0;
450 }
451
452 DWORD result = TlsAlloc();
453 if (result == TLS_OUT_OF_INDEXES) {
454 return -1;
455 }
456 /* In Windows, platform-specific key type is DWORD. */
457 key->_key = result;
458 key->_is_initialized = 1;
459 return 0;
460 }
461
462 void
PyThread_tss_delete(Py_tss_t * key)463 PyThread_tss_delete(Py_tss_t *key)
464 {
465 assert(key != NULL);
466 /* If the key has not been created, function is silently skipped. */
467 if (!key->_is_initialized) {
468 return;
469 }
470
471 TlsFree(key->_key);
472 key->_key = TLS_OUT_OF_INDEXES;
473 key->_is_initialized = 0;
474 }
475
476 int
PyThread_tss_set(Py_tss_t * key,void * value)477 PyThread_tss_set(Py_tss_t *key, void *value)
478 {
479 assert(key != NULL);
480 BOOL ok = TlsSetValue(key->_key, value);
481 return ok ? 0 : -1;
482 }
483
484 void *
PyThread_tss_get(Py_tss_t * key)485 PyThread_tss_get(Py_tss_t *key)
486 {
487 assert(key != NULL);
488 /* because TSS is used in the Py_END_ALLOW_THREAD macro,
489 * it is necessary to preserve the windows error state, because
490 * it is assumed to be preserved across the call to the macro.
491 * Ideally, the macro should be fixed, but it is simpler to
492 * do it here.
493 */
494 DWORD error = GetLastError();
495 void *result = TlsGetValue(key->_key);
496 SetLastError(error);
497 return result;
498 }
499