semeventmulti-posix.cpp@ 16522

Last change on this file since 16522 was 14318, checked in by vboxsync, 16 years ago
Fix a couple of words doubled in comments. No code changes.
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1	/* $Id: semeventmulti-posix.cpp 14318 2008-11-18 16:56:53Z vboxsync $ */
2	/** @file
3	* IPRT - Multiple Release Event Semaphore, POSIX.
4	*/
5
6	/*
7	* Copyright (C) 2006-2007 Sun Microsystems, Inc.
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*
17	* The contents of this file may alternatively be used under the terms
18	* of the Common Development and Distribution License Version 1.0
19	* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20	* VirtualBox OSE distribution, in which case the provisions of the
21	* CDDL are applicable instead of those of the GPL.
22	*
23	* You may elect to license modified versions of this file under the
24	* terms and conditions of either the GPL or the CDDL or both.
25	*
26	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
27	* Clara, CA 95054 USA or visit http://www.sun.com if you need
28	* additional information or have any questions.
29	*/
30
31	/*******************************************************************************
32	* Header Files *
33	*******************************************************************************/
34	#include <iprt/semaphore.h>
35	#include <iprt/assert.h>
36	#include <iprt/alloc.h>
37	#include <iprt/asm.h>
38	#include <iprt/err.h>
39
40	#include <errno.h>
41	#include <pthread.h>
42	#include <unistd.h>
43	#include <sys/time.h>
44
45
46	/*******************************************************************************
47	* Structures and Typedefs *
48	*******************************************************************************/
49	/** Posix internal representation of a Mutex Multi semaphore.
50	* The POSIX implementation uses a mutex and a condition variable to implement
51	* the automatic reset event semaphore semantics. */
52	struct RTSEMEVENTMULTIINTERNAL
53	{
54	/** pthread condition. */
55	pthread_cond_t Cond;
56	/** pthread mutex which protects the condition and the event state. */
57	pthread_mutex_t Mutex;
58	/** The state of the semaphore.
59	* This is operated while owning mutex and using atomic updating. */
60	volatile uint32_t u32State;
61	/** Number of waiters. */
62	volatile uint32_t cWaiters;
63	};
64
65	/** The valus of the u32State variable in RTSEMEVENTMULTIINTERNAL.
66	* @{ */
67	/** The object isn't initialized. */
68	#define EVENTMULTI_STATE_UNINITIALIZED 0
69	/** The semaphore is signaled. */
70	#define EVENTMULTI_STATE_SIGNALED 0xff00ff00
71	/** The semaphore is not signaled. */
72	#define EVENTMULTI_STATE_NOT_SIGNALED 0x00ff00ff
73	/** @} */
74
75
76
77	/**
78	* Validate an event multi semaphore handle passed to one of the interface.
79	*
80	* @returns true if valid.
81	* @returns false if invalid.
82	* @param pThis Pointer to the event semaphore to validate.
83	*/
84	inline bool rtsemEventMultiValid(struct RTSEMEVENTMULTIINTERNAL *pThis)
85	{
86	if ((uintptr_t)pThis < 0x10000)
87	return false;
88
89	uint32_t u32 = pThis->u32State; /* this is volatile, so a explicit read like this is needed. */
90	if ( u32 != EVENTMULTI_STATE_NOT_SIGNALED
91	&& u32 != EVENTMULTI_STATE_SIGNALED)
92	return false;
93
94	return true;
95	}
96
97
98	RTDECL(int) RTSemEventMultiCreate(PRTSEMEVENTMULTI pEventMultiSem)
99	{
100	int rc;
101
102	/*
103	* Allocate semaphore handle.
104	*/
105	struct RTSEMEVENTMULTIINTERNAL pThis = (struct RTSEMEVENTMULTIINTERNAL )RTMemAlloc(sizeof(struct RTSEMEVENTMULTIINTERNAL));
106	if (pThis)
107	{
108	/*
109	* Create the condition variable.
110	*/
111	pthread_condattr_t CondAttr;
112	rc = pthread_condattr_init(&CondAttr);
113	if (!rc)
114	{
115	rc = pthread_cond_init(&pThis->Cond, &CondAttr);
116	if (!rc)
117	{
118	/*
119	* Create the semaphore.
120	*/
121	pthread_mutexattr_t MutexAttr;
122	rc = pthread_mutexattr_init(&MutexAttr);
123	if (!rc)
124	{
125	rc = pthread_mutex_init(&pThis->Mutex, &MutexAttr);
126	if (!rc)
127	{
128	pthread_mutexattr_destroy(&MutexAttr);
129	pthread_condattr_destroy(&CondAttr);
130
131	ASMAtomicXchgU32(&pThis->u32State, EVENTMULTI_STATE_NOT_SIGNALED);
132	ASMAtomicXchgU32(&pThis->cWaiters, 0);
133
134	*pEventMultiSem = pThis;
135	return VINF_SUCCESS;
136	}
137
138	pthread_mutexattr_destroy(&MutexAttr);
139	}
140	pthread_cond_destroy(&pThis->Cond);
141	}
142	pthread_condattr_destroy(&CondAttr);
143	}
144
145	rc = RTErrConvertFromErrno(rc);
146	RTMemFree(pThis);
147	}
148	else
149	rc = VERR_NO_MEMORY;
150
151	return rc;
152
153	}
154
155
156	RTDECL(int) RTSemEventMultiDestroy(RTSEMEVENTMULTI EventMultiSem)
157	{
158	/*
159	* Validate handle.
160	*/
161	if (!rtsemEventMultiValid(EventMultiSem))
162	{
163	AssertMsgFailed(("Invalid handle %p!\n", EventMultiSem));
164	return VERR_INVALID_HANDLE;
165	}
166
167	/*
168	* Abort all waiters forcing them to return failure.
169	*/
170	struct RTSEMEVENTMULTIINTERNAL *pThis = EventMultiSem;
171	int rc;
172	for (int i = 30; i > 0; i--)
173	{
174	ASMAtomicXchgU32(&pThis->u32State, EVENTMULTI_STATE_UNINITIALIZED);
175	rc = pthread_cond_destroy(&pThis->Cond);
176	if (rc != EBUSY)
177	break;
178	pthread_cond_broadcast(&pThis->Cond);
179	usleep(1000);
180	}
181	if (rc)
182	{
183	AssertMsgFailed(("Failed to destroy event sem %p, rc=%d.\n", EventMultiSem, rc));
184	return RTErrConvertFromErrno(rc);
185	}
186
187	/*
188	* Destroy the semaphore
189	* If it's busy we'll wait a bit to give the threads a chance to be scheduled.
190	*/
191	for (int i = 30; i > 0; i--)
192	{
193	rc = pthread_mutex_destroy(&pThis->Mutex);
194	if (rc != EBUSY)
195	break;
196	usleep(1000);
197	}
198	if (rc)
199	{
200	AssertMsgFailed(("Failed to destroy event sem %p, rc=%d. (mutex)\n", EventMultiSem, rc));
201	return RTErrConvertFromErrno(rc);
202	}
203
204	/*
205	* Free the semaphore memory and be gone.
206	*/
207	RTMemFree(pThis);
208	return VINF_SUCCESS;
209	}
210
211
212	RTDECL(int) RTSemEventMultiSignal(RTSEMEVENTMULTI EventMultiSem)
213	{
214	/*
215	* Validate input.
216	*/
217	if (!rtsemEventMultiValid(EventMultiSem))
218	{
219	AssertMsgFailed(("Invalid handle %p!\n", EventMultiSem));
220	return VERR_INVALID_HANDLE;
221	}
222
223	/*
224	* Lock the mutex semaphore.
225	*/
226	struct RTSEMEVENTMULTIINTERNAL *pThis = EventMultiSem;
227	int rc = pthread_mutex_lock(&pThis->Mutex);
228	if (rc)
229	{
230	AssertMsgFailed(("Failed to lock event sem %p, rc=%d.\n", EventMultiSem, rc));
231	return RTErrConvertFromErrno(rc);
232	}
233
234	/*
235	* Check the state.
236	*/
237	if (pThis->u32State == EVENTMULTI_STATE_NOT_SIGNALED)
238	{
239	ASMAtomicXchgU32(&pThis->u32State, EVENTMULTI_STATE_SIGNALED);
240	rc = pthread_cond_broadcast(&pThis->Cond);
241	AssertMsg(!rc, ("Failed to signal event sem %p, rc=%d.\n", EventMultiSem, rc));
242	}
243	else if (pThis->u32State == EVENTMULTI_STATE_SIGNALED)
244	{
245	rc = pthread_cond_broadcast(&pThis->Cond); /* give'm another kick... */
246	AssertMsg(!rc, ("Failed to signal event sem %p, rc=%d. (2)\n", EventMultiSem, rc));
247	}
248	else
249	rc = VERR_SEM_DESTROYED;
250
251	/*
252	* Release the mutex and return.
253	*/
254	int rc2 = pthread_mutex_unlock(&pThis->Mutex);
255	AssertMsg(!rc2, ("Failed to unlock event sem %p, rc=%d.\n", EventMultiSem, rc));
256	if (rc)
257	return RTErrConvertFromErrno(rc);
258	if (rc2)
259	return RTErrConvertFromErrno(rc2);
260
261	return VINF_SUCCESS;
262	}
263
264
265	RTDECL(int) RTSemEventMultiReset(RTSEMEVENTMULTI EventMultiSem)
266	{
267	/*
268	* Validate input.
269	*/
270	if (!rtsemEventMultiValid(EventMultiSem))
271	{
272	AssertMsgFailed(("Invalid handle %p!\n", EventMultiSem));
273	return VERR_INVALID_HANDLE;
274	}
275
276	/*
277	* Lock the mutex semaphore.
278	*/
279	struct RTSEMEVENTMULTIINTERNAL *pThis = EventMultiSem;
280	int rc = pthread_mutex_lock(&pThis->Mutex);
281	if (rc)
282	{
283	AssertMsgFailed(("Failed to lock event multi sem %p, rc=%d.\n", EventMultiSem, rc));
284	return RTErrConvertFromErrno(rc);
285	}
286
287	/*
288	* Check the state.
289	*/
290	if (pThis->u32State == EVENTMULTI_STATE_SIGNALED)
291	ASMAtomicXchgU32(&pThis->u32State, EVENTMULTI_STATE_NOT_SIGNALED);
292	else if (pThis->u32State != EVENTMULTI_STATE_NOT_SIGNALED)
293	rc = VERR_SEM_DESTROYED;
294
295	/*
296	* Release the mutex and return.
297	*/
298	rc = pthread_mutex_unlock(&pThis->Mutex);
299	if (rc)
300	{
301	AssertMsgFailed(("Failed to unlock event multi sem %p, rc=%d.\n", EventMultiSem, rc));
302	return RTErrConvertFromErrno(rc);
303	}
304
305	return VINF_SUCCESS;
306
307	}
308
309
310	static int rtSemEventMultiWait(RTSEMEVENTMULTI EventMultiSem, unsigned cMillies, bool fAutoResume)
311	{
312	/*
313	* Validate input.
314	*/
315	if (!rtsemEventMultiValid(EventMultiSem))
316	{
317	AssertMsgFailed(("Invalid handle %p!\n", EventMultiSem));
318	return VERR_INVALID_HANDLE;
319	}
320
321	/*
322	* Timed or indefinite wait?
323	*/
324	struct RTSEMEVENTMULTIINTERNAL *pThis = EventMultiSem;
325	if (cMillies == RT_INDEFINITE_WAIT)
326	{
327	/* take mutex */
328	int rc = pthread_mutex_lock(&pThis->Mutex);
329	if (rc)
330	{
331	AssertMsgFailed(("Failed to lock event multi sem %p, rc=%d.\n", EventMultiSem, rc));
332	return RTErrConvertFromErrno(rc);
333	}
334	ASMAtomicIncU32(&pThis->cWaiters);
335
336	for (;;)
337	{
338	/* check state. */
339	if (pThis->u32State == EVENTMULTI_STATE_SIGNALED)
340	{
341	ASMAtomicDecU32(&pThis->cWaiters);
342	rc = pthread_mutex_unlock(&pThis->Mutex);
343	AssertMsg(!rc, ("Failed to unlock event multi sem %p, rc=%d.\n", EventMultiSem, rc)); NOREF(rc);
344	return VINF_SUCCESS;
345	}
346	if (pThis->u32State == EVENTMULTI_STATE_UNINITIALIZED)
347	{
348	rc = pthread_mutex_unlock(&pThis->Mutex);
349	AssertMsg(!rc, ("Failed to unlock event multi sem %p, rc=%d.\n", EventMultiSem, rc)); NOREF(rc);
350	return VERR_SEM_DESTROYED;
351	}
352
353	/* wait */
354	rc = pthread_cond_wait(&pThis->Cond, &pThis->Mutex);
355	if (rc)
356	{
357	AssertMsgFailed(("Failed to wait on event multi sem %p, rc=%d.\n", EventMultiSem, rc));
358	ASMAtomicDecU32(&pThis->cWaiters);
359	int rc2 = pthread_mutex_unlock(&pThis->Mutex);
360	AssertMsg(!rc2, ("Failed to unlock event multi sem %p, rc=%d.\n", EventMultiSem, rc2)); NOREF(rc2);
361	return RTErrConvertFromErrno(rc);
362	}
363	}
364	}
365	else
366	{
367	/*
368	* Get current time and calc end of wait time.
369	*/
370	/** @todo Something is braindead here. we're getting occational timeouts after no time has
371	* elapsed on linux 2.6.23. (ata code typically)
372	*
373	* The general problem here is that we're using the realtime clock, i.e. the wall clock
374	* that is subject to ntp updates and user alteration, so we will have to compenstate
375	* for this by using RTTimeMilliTS together with the clock_gettime()/gettimeofday() call.
376	* Joy, oh joy. */
377	struct timespec ts = {0,0};
378	#ifdef RT_OS_DARWIN
379	struct timeval tv = {0,0};
380	gettimeofday(&tv, NULL);
381	ts.tv_sec = tv.tv_sec;
382	ts.tv_nsec = tv.tv_usec * 1000;
383	#else
384	clock_gettime(CLOCK_REALTIME, &ts);
385	#endif
386	if (cMillies != 0)
387	{
388	ts.tv_nsec += (cMillies % 1000) * 1000000;
389	ts.tv_sec += cMillies / 1000;
390	if (ts.tv_nsec >= 1000000000)
391	{
392	ts.tv_nsec -= 1000000000;
393	ts.tv_sec++;
394	}
395	}
396
397	/* take mutex */
398	#ifdef RT_OS_DARWIN
399	int rc = pthread_mutex_lock(&pThis->Mutex);
400	#else
401	int rc = pthread_mutex_timedlock(&pThis->Mutex, &ts);
402	#endif
403	if (rc)
404	{
405	AssertMsg(rc == ETIMEDOUT, ("Failed to lock event multi sem %p, rc=%d.\n", EventMultiSem, rc));
406	return RTErrConvertFromErrno(rc);
407	}
408	ASMAtomicIncU32(&pThis->cWaiters);
409
410	for (;;)
411	{
412	/* check state. */
413	if (pThis->u32State == EVENTMULTI_STATE_SIGNALED)
414	{
415	ASMAtomicXchgU32(&pThis->u32State, EVENTMULTI_STATE_NOT_SIGNALED);
416	ASMAtomicDecU32(&pThis->cWaiters);
417	rc = pthread_mutex_unlock(&pThis->Mutex);
418	AssertMsg(!rc, ("Failed to unlock event multi sem %p, rc=%d.\n", EventMultiSem, rc)); NOREF(rc);
419	return VINF_SUCCESS;
420	}
421	if (pThis->u32State == EVENTMULTI_STATE_UNINITIALIZED)
422	{
423	rc = pthread_mutex_unlock(&pThis->Mutex);
424	AssertMsg(!rc, ("Failed to unlock event multi sem %p, rc=%d.\n", EventMultiSem, rc)); NOREF(rc);
425	return VERR_SEM_DESTROYED;
426	}
427
428	/* wait */
429	rc = pthread_cond_timedwait(&pThis->Cond, &pThis->Mutex, &ts);
430	if (rc && (rc != EINTR \|\| !fAutoResume)) /* according to SuS this function shall not return EINTR, but linux man page says differently. */
431	{
432	AssertMsg(rc == ETIMEDOUT, ("Failed to wait on event multi sem %p, rc=%d.\n", EventMultiSem, rc));
433	ASMAtomicDecU32(&pThis->cWaiters);
434	int rc2 = pthread_mutex_unlock(&pThis->Mutex);
435	AssertMsg(!rc2, ("Failed to unlock event multi sem %p, rc=%d.\n", EventMultiSem, rc2)); NOREF(rc2);
436	return RTErrConvertFromErrno(rc);
437	}
438	}
439	}
440	}
441
442
443	RTDECL(int) RTSemEventMultiWait(RTSEMEVENTMULTI EventMultiSem, unsigned cMillies)
444	{
445	int rc = rtSemEventMultiWait(EventMultiSem, cMillies, true);
446	Assert(rc != VERR_INTERRUPTED);
447	return rc;
448	}
449
450
451	RTDECL(int) RTSemEventMultiWaitNoResume(RTSEMEVENTMULTI EventMultiSem, unsigned cMillies)
452	{
453	return rtSemEventMultiWait(EventMultiSem, cMillies, false);
454	}
455

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source: vbox/trunk/src/VBox/Runtime/r3/posix/semeventmulti-posix.cpp@ 16522

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