Issue #7282: Fix a memory leak when an RLock was used in a thread other
[python.git] / Python / thread_nt.h
blob633fe4018fcbfc8f46af6321fb6289aee511e310
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 */
6 #include <windows.h>
7 #include <limits.h>
8 #ifdef HAVE_PROCESS_H
9 #include <process.h>
10 #endif
12 typedef struct NRMUTEX {
13 LONG owned ;
14 DWORD thread_id ;
15 HANDLE hevent ;
16 } NRMUTEX, *PNRMUTEX ;
19 BOOL
20 InitializeNonRecursiveMutex(PNRMUTEX mutex)
22 mutex->owned = -1 ; /* No threads have entered NonRecursiveMutex */
23 mutex->thread_id = 0 ;
24 mutex->hevent = CreateEvent(NULL, FALSE, FALSE, NULL) ;
25 return mutex->hevent != NULL ; /* TRUE if the mutex is created */
28 VOID
29 DeleteNonRecursiveMutex(PNRMUTEX mutex)
31 /* No in-use check */
32 CloseHandle(mutex->hevent) ;
33 mutex->hevent = NULL ; /* Just in case */
36 DWORD
37 EnterNonRecursiveMutex(PNRMUTEX mutex, BOOL wait)
39 /* Assume that the thread waits successfully */
40 DWORD ret ;
42 /* InterlockedIncrement(&mutex->owned) == 0 means that no thread currently owns the mutex */
43 if (!wait)
45 if (InterlockedCompareExchange(&mutex->owned, 0, -1) != -1)
46 return WAIT_TIMEOUT ;
47 ret = WAIT_OBJECT_0 ;
49 else
50 ret = InterlockedIncrement(&mutex->owned) ?
51 /* Some thread owns the mutex, let's wait... */
52 WaitForSingleObject(mutex->hevent, INFINITE) : WAIT_OBJECT_0 ;
54 mutex->thread_id = GetCurrentThreadId() ; /* We own it */
55 return ret ;
58 BOOL
59 LeaveNonRecursiveMutex(PNRMUTEX mutex)
61 /* We don't own the mutex */
62 mutex->thread_id = 0 ;
63 return
64 InterlockedDecrement(&mutex->owned) < 0 ||
65 SetEvent(mutex->hevent) ; /* Other threads are waiting, wake one on them up */
68 PNRMUTEX
69 AllocNonRecursiveMutex(void)
71 PNRMUTEX mutex = (PNRMUTEX)malloc(sizeof(NRMUTEX)) ;
72 if (mutex && !InitializeNonRecursiveMutex(mutex))
74 free(mutex) ;
75 mutex = NULL ;
77 return mutex ;
80 void
81 FreeNonRecursiveMutex(PNRMUTEX mutex)
83 if (mutex)
85 DeleteNonRecursiveMutex(mutex) ;
86 free(mutex) ;
90 long PyThread_get_thread_ident(void);
93 * Initialization of the C package, should not be needed.
95 static void
96 PyThread__init_thread(void)
101 * Thread support.
104 typedef struct {
105 void (*func)(void*);
106 void *arg;
107 } callobj;
109 /* thunker to call adapt between the function type used by the system's
110 thread start function and the internally used one. */
111 #if defined(MS_WINCE)
112 static DWORD WINAPI
113 #else
114 static unsigned __stdcall
115 #endif
116 bootstrap(void *call)
118 callobj *obj = (callobj*)call;
119 void (*func)(void*) = obj->func;
120 void *arg = obj->arg;
121 HeapFree(GetProcessHeap(), 0, obj);
122 func(arg);
123 return 0;
126 long
127 PyThread_start_new_thread(void (*func)(void *), void *arg)
129 HANDLE hThread;
130 unsigned threadID;
131 callobj *obj;
133 dprintf(("%ld: PyThread_start_new_thread called\n",
134 PyThread_get_thread_ident()));
135 if (!initialized)
136 PyThread_init_thread();
138 obj = (callobj*)HeapAlloc(GetProcessHeap(), 0, sizeof(*obj));
139 if (!obj)
140 return -1;
141 obj->func = func;
142 obj->arg = arg;
143 #if defined(MS_WINCE)
144 hThread = CreateThread(NULL,
145 Py_SAFE_DOWNCAST(_pythread_stacksize, Py_ssize_t, SIZE_T),
146 bootstrap, obj, 0, &threadID);
147 #else
148 hThread = (HANDLE)_beginthreadex(0,
149 Py_SAFE_DOWNCAST(_pythread_stacksize,
150 Py_ssize_t, unsigned int),
151 bootstrap, obj,
152 0, &threadID);
153 #endif
154 if (hThread == 0) {
155 #if defined(MS_WINCE)
156 /* Save error in variable, to prevent PyThread_get_thread_ident
157 from clobbering it. */
158 unsigned e = GetLastError();
159 dprintf(("%ld: PyThread_start_new_thread failed, win32 error code %u\n",
160 PyThread_get_thread_ident(), e));
161 #else
162 /* I've seen errno == EAGAIN here, which means "there are
163 * too many threads".
165 int e = errno;
166 dprintf(("%ld: PyThread_start_new_thread failed, errno %d\n",
167 PyThread_get_thread_ident(), e));
168 #endif
169 threadID = (unsigned)-1;
170 HeapFree(GetProcessHeap(), 0, obj);
172 else {
173 dprintf(("%ld: PyThread_start_new_thread succeeded: %p\n",
174 PyThread_get_thread_ident(), (void*)hThread));
175 CloseHandle(hThread);
177 return (long) threadID;
181 * Return the thread Id instead of an handle. The Id is said to uniquely identify the
182 * thread in the system
184 long
185 PyThread_get_thread_ident(void)
187 if (!initialized)
188 PyThread_init_thread();
190 return GetCurrentThreadId();
193 void
194 PyThread_exit_thread(void)
196 dprintf(("%ld: PyThread_exit_thread called\n", PyThread_get_thread_ident()));
197 if (!initialized)
198 exit(0);
199 #if defined(MS_WINCE)
200 ExitThread(0);
201 #else
202 _endthreadex(0);
203 #endif
206 #ifndef NO_EXIT_PROG
207 void
208 PyThread_exit_prog(int status)
210 dprintf(("PyThread_exit_prog(%d) called\n", status));
211 if (!initialized)
212 exit(status);
214 #endif /* NO_EXIT_PROG */
217 * Lock support. It has too be implemented as semaphores.
218 * I [Dag] tried to implement it with mutex but I could find a way to
219 * tell whether a thread already own the lock or not.
221 PyThread_type_lock
222 PyThread_allocate_lock(void)
224 PNRMUTEX aLock;
226 dprintf(("PyThread_allocate_lock called\n"));
227 if (!initialized)
228 PyThread_init_thread();
230 aLock = AllocNonRecursiveMutex() ;
232 dprintf(("%ld: PyThread_allocate_lock() -> %p\n", PyThread_get_thread_ident(), aLock));
234 return (PyThread_type_lock) aLock;
237 void
238 PyThread_free_lock(PyThread_type_lock aLock)
240 dprintf(("%ld: PyThread_free_lock(%p) called\n", PyThread_get_thread_ident(),aLock));
242 FreeNonRecursiveMutex(aLock) ;
246 * Return 1 on success if the lock was acquired
248 * and 0 if the lock was not acquired. This means a 0 is returned
249 * if the lock has already been acquired by this thread!
252 PyThread_acquire_lock(PyThread_type_lock aLock, int waitflag)
254 int success ;
256 dprintf(("%ld: PyThread_acquire_lock(%p, %d) called\n", PyThread_get_thread_ident(),aLock, waitflag));
258 success = aLock && EnterNonRecursiveMutex((PNRMUTEX) aLock, (waitflag ? INFINITE : 0)) == WAIT_OBJECT_0 ;
260 dprintf(("%ld: PyThread_acquire_lock(%p, %d) -> %d\n", PyThread_get_thread_ident(),aLock, waitflag, success));
262 return success;
265 void
266 PyThread_release_lock(PyThread_type_lock aLock)
268 dprintf(("%ld: PyThread_release_lock(%p) called\n", PyThread_get_thread_ident(),aLock));
270 if (!(aLock && LeaveNonRecursiveMutex((PNRMUTEX) aLock)))
271 dprintf(("%ld: Could not PyThread_release_lock(%p) error: %ld\n", PyThread_get_thread_ident(), aLock, GetLastError()));
274 /* minimum/maximum thread stack sizes supported */
275 #define THREAD_MIN_STACKSIZE 0x8000 /* 32kB */
276 #define THREAD_MAX_STACKSIZE 0x10000000 /* 256MB */
278 /* set the thread stack size.
279 * Return 0 if size is valid, -1 otherwise.
281 static int
282 _pythread_nt_set_stacksize(size_t size)
284 /* set to default */
285 if (size == 0) {
286 _pythread_stacksize = 0;
287 return 0;
290 /* valid range? */
291 if (size >= THREAD_MIN_STACKSIZE && size < THREAD_MAX_STACKSIZE) {
292 _pythread_stacksize = size;
293 return 0;
296 return -1;
299 #define THREAD_SET_STACKSIZE(x) _pythread_nt_set_stacksize(x)
302 /* use native Windows TLS functions */
303 #define Py_HAVE_NATIVE_TLS
305 #ifdef Py_HAVE_NATIVE_TLS
307 PyThread_create_key(void)
309 return (int) TlsAlloc();
312 void
313 PyThread_delete_key(int key)
315 TlsFree(key);
318 /* We must be careful to emulate the strange semantics implemented in thread.c,
319 * where the value is only set if it hasn't been set before.
322 PyThread_set_key_value(int key, void *value)
324 BOOL ok;
325 void *oldvalue;
327 assert(value != NULL);
328 oldvalue = TlsGetValue(key);
329 if (oldvalue != NULL)
330 /* ignore value if already set */
331 return 0;
332 ok = TlsSetValue(key, value);
333 if (!ok)
334 return -1;
335 return 0;
338 void *
339 PyThread_get_key_value(int key)
341 /* because TLS is used in the Py_END_ALLOW_THREAD macro,
342 * it is necessary to preserve the windows error state, because
343 * it is assumed to be preserved across the call to the macro.
344 * Ideally, the macro should be fixed, but it is simpler to
345 * do it here.
347 DWORD error = GetLastError();
348 void *result = TlsGetValue(key);
349 SetLastError(error);
350 return result;
353 void
354 PyThread_delete_key_value(int key)
356 /* NULL is used as "key missing", and it is also the default
357 * given by TlsGetValue() if nothing has been set yet.
359 TlsSetValue(key, NULL);
362 /* reinitialization of TLS is not necessary after fork when using
363 * the native TLS functions. And forking isn't supported on Windows either.
365 void
366 PyThread_ReInitTLS(void)
369 #endif