semrw-posix.cpp@ 25723

Last change on this file since 25723 was 25723, checked in by vboxsync, 15 years ago
iprt/RTSemRW: A little cleanup.
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1	/* $Id: semrw-posix.cpp 25723 2010-01-11 14:28:57Z vboxsync $ */
2	/** @file
3	* IPRT - Read-Write 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 "internal/iprt.h"
36
37	#include <iprt/asm.h>
38	#include <iprt/assert.h>
39	#include <iprt/err.h>
40	#include <iprt/lockvalidator.h>
41	#include <iprt/mem.h>
42	#include <iprt/thread.h>
43
44	#include <errno.h>
45	#include <pthread.h>
46	#include <unistd.h>
47	#include <sys/time.h>
48
49	#include "internal/magics.h"
50	#include "internal/strict.h"
51
52
53	/*******************************************************************************
54	* Defined Constants And Macros *
55	*******************************************************************************/
56	/** @todo move this to r3/posix/something.h. */
57	#ifdef RT_OS_SOLARIS
58	# define ATOMIC_GET_PTHREAD_T(pvVar, pThread) ASMAtomicReadSize(pvVar, pThread)
59	# define ATOMIC_SET_PTHREAD_T(pvVar, pThread) ASMAtomicWriteSize(pvVar, pThread)
60	#else
61	AssertCompileSize(pthread_t, sizeof(void *));
62	# define ATOMIC_GET_PTHREAD_T(pvVar, pThread) do { (pThread) = (pthread_t)ASMAtomicReadPtr((void volatile *)pvVar); } while (0)
63	# define ATOMIC_SET_PTHREAD_T(pvVar, pThread) ASMAtomicWritePtr((void volatile )pvVar, (void *)pThread)
64	#endif
65
66
67	/*******************************************************************************
68	* Structures and Typedefs *
69	*******************************************************************************/
70	/** Posix internal representation of a read-write semaphore. */
71	struct RTSEMRWINTERNAL
72	{
73	/** The usual magic. (RTSEMRW_MAGIC) */
74	uint32_t u32Magic;
75	/** The number of readers.
76	* (For preventing screwing up the lock on linux). */
77	uint32_t volatile cReaders;
78	/** Number of write recursions. */
79	uint32_t cWrites;
80	/** Number of read recursions by the writer. */
81	uint32_t cWriterReads;
82	/** The write owner of the lock. */
83	volatile pthread_t Writer;
84	/** pthread rwlock. */
85	pthread_rwlock_t RWLock;
86	#ifdef RTSEMRW_STRICT
87	/** The validator record for the writer. */
88	RTLOCKVALRECEXCL ValidatorWrite;
89	/** The validator record for the readers. */
90	RTLOCKVALRECSHRD ValidatorRead;
91	#endif
92	};
93
94
95
96	#undef RTSemRWCreate
97	RTDECL(int) RTSemRWCreate(PRTSEMRW phRWSem)
98	{
99	return RTSemRWCreateEx(phRWSem, 0 /fFlags/, NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_NONE, "RTSemRW");
100	}
101
102
103	RTDECL(int) RTSemRWCreateEx(PRTSEMRW phRWSem, uint32_t fFlags,
104	RTLOCKVALCLASS hClass, uint32_t uSubClass, const char *pszNameFmt, ...)
105	{
106	AssertReturn(!(fFlags & ~RTSEMRW_FLAGS_NO_LOCK_VAL), VERR_INVALID_PARAMETER);
107
108	/*
109	* Allocate handle.
110	*/
111	int rc;
112	struct RTSEMRWINTERNAL pThis = (struct RTSEMRWINTERNAL )RTMemAlloc(sizeof(struct RTSEMRWINTERNAL));
113	if (pThis)
114	{
115	/*
116	* Create the rwlock.
117	*/
118	pthread_rwlockattr_t Attr;
119	rc = pthread_rwlockattr_init(&Attr);
120	if (!rc)
121	{
122	rc = pthread_rwlock_init(&pThis->RWLock, &Attr);
123	if (!rc)
124	{
125	pThis->u32Magic = RTSEMRW_MAGIC;
126	pThis->cReaders = 0;
127	pThis->cWrites = 0;
128	pThis->cWriterReads = 0;
129	pThis->Writer = (pthread_t)-1;
130	#ifdef RTSEMRW_STRICT
131	bool const fLVEnabled = !(fFlags & RTSEMRW_FLAGS_NO_LOCK_VAL);
132	va_list va;
133	va_start(va, pszNameFmt);
134	RTLockValidatorRecExclInitV(&pThis->ValidatorWrite, hClass, uSubClass, pThis, fLVEnabled, pszNameFmt, va);
135	va_end(va);
136	va_start(va, pszNameFmt);
137	RTLockValidatorRecSharedInitV(&pThis->ValidatorRead, hClass, uSubClass, pThis, false /fSignaller/,
138	fLVEnabled, pszNameFmt, va);
139	va_end(va);
140	RTLockValidatorRecMakeSiblings(&pThis->ValidatorWrite.Core, &pThis->ValidatorRead.Core);
141	#endif
142	*phRWSem = pThis;
143	return VINF_SUCCESS;
144	}
145	}
146
147	rc = RTErrConvertFromErrno(rc);
148	RTMemFree(pThis);
149	}
150	else
151	rc = VERR_NO_MEMORY;
152
153	return rc;
154	}
155
156
157	RTDECL(int) RTSemRWDestroy(RTSEMRW hRWSem)
158	{
159	/*
160	* Validate input, nil handle is fine.
161	*/
162	struct RTSEMRWINTERNAL *pThis = hRWSem;
163	if (pThis == NIL_RTSEMRW)
164	return VINF_SUCCESS;
165	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
166	AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
167	("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
168	VERR_INVALID_HANDLE);
169	Assert(pThis->Writer == (pthread_t)-1);
170	Assert(!pThis->cReaders);
171	Assert(!pThis->cWrites);
172	Assert(!pThis->cWriterReads);
173
174	/*
175	* Try destroy it.
176	*/
177	AssertReturn(ASMAtomicCmpXchgU32(&pThis->u32Magic, ~RTSEMRW_MAGIC, RTSEMRW_MAGIC), VERR_INVALID_HANDLE);
178	int rc = pthread_rwlock_destroy(&pThis->RWLock);
179	if (!rc)
180	{
181	#ifdef RTSEMRW_STRICT
182	RTLockValidatorRecSharedDelete(&pThis->ValidatorRead);
183	RTLockValidatorRecExclDelete(&pThis->ValidatorWrite);
184	#endif
185	RTMemFree(pThis);
186	rc = VINF_SUCCESS;
187	}
188	else
189	{
190	ASMAtomicWriteU32(&pThis->u32Magic, RTSEMRW_MAGIC);
191	AssertMsgFailed(("Failed to destroy read-write sem %p, rc=%d.\n", hRWSem, rc));
192	rc = RTErrConvertFromErrno(rc);
193	}
194
195	return rc;
196	}
197
198
199	RTDECL(uint32_t) RTSemRWSetSubClass(RTSEMRW hRWSem, uint32_t uSubClass)
200	{
201	#ifdef RTSEMRW_STRICT
202	/*
203	* Validate handle.
204	*/
205	struct RTSEMRWINTERNAL *pThis = hRWSem;
206	AssertPtrReturn(pThis, RTLOCKVAL_SUB_CLASS_INVALID);
207	AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, RTLOCKVAL_SUB_CLASS_INVALID);
208
209	RTLockValidatorRecSharedSetSubClass(&pThis->ValidatorRead, uSubClass);
210	return RTLockValidatorRecExclSetSubClass(&pThis->ValidatorWrite, uSubClass);
211	#else
212	return RTLOCKVAL_SUB_CLASS_INVALID;
213	#endif
214	}
215
216
217	DECL_FORCE_INLINE(int) rtSemRWRequestRead(RTSEMRW hRWSem, RTMSINTERVAL cMillies, PCRTLOCKVALSRCPOS pSrcPos)
218	{
219	/*
220	* Validate input.
221	*/
222	struct RTSEMRWINTERNAL *pThis = hRWSem;
223	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
224	AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
225	("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
226	VERR_INVALID_HANDLE);
227
228	/*
229	* Check if it's the writer (implement write+read recursion).
230	*/
231	pthread_t Self = pthread_self();
232	pthread_t Writer;
233	ATOMIC_GET_PTHREAD_T(&pThis->Writer, &Writer);
234	if (Writer == Self)
235	{
236	#ifdef RTSEMRW_STRICT
237	int rc9 = RTLockValidatorRecExclRecursionMixed(&pThis->ValidatorWrite, &pThis->ValidatorRead.Core, pSrcPos);
238	if (RT_FAILURE(rc9))
239	return rc9;
240	#endif
241	Assert(pThis->cWriterReads < INT32_MAX);
242	pThis->cWriterReads++;
243	return VINF_SUCCESS;
244	}
245
246	/*
247	* Try lock it.
248	*/
249	RTTHREAD hThreadSelf = NIL_RTTHREAD;
250	if (cMillies > 0)
251	{
252	#ifdef RTSEMRW_STRICT
253	hThreadSelf = RTThreadSelfAutoAdopt();
254	int rc9 = RTLockValidatorRecSharedCheckOrderAndBlocking(&pThis->ValidatorRead, hThreadSelf, pSrcPos, true,
255	cMillies, RTTHREADSTATE_RW_READ, true);
256	if (RT_FAILURE(rc9))
257	return rc9;
258	#else
259	hThreadSelf = RTThreadSelf();
260	RTThreadBlocking(hThreadSelf, RTTHREADSTATE_RW_READ, true);
261	#endif
262	}
263
264	if (cMillies == RT_INDEFINITE_WAIT)
265	{
266	/* take rwlock */
267	int rc = pthread_rwlock_rdlock(&pThis->RWLock);
268	RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_READ);
269	if (rc)
270	{
271	AssertMsgFailed(("Failed read lock read-write sem %p, rc=%d.\n", hRWSem, rc));
272	return RTErrConvertFromErrno(rc);
273	}
274	}
275	else
276	{
277	#ifdef RT_OS_DARWIN
278	AssertMsgFailed(("Not implemented on Darwin yet because of incomplete pthreads API."));
279	return VERR_NOT_IMPLEMENTED;
280
281	#else /* !RT_OS_DARWIN */
282	/*
283	* Get current time and calc end of wait time.
284	*/
285	struct timespec ts = {0,0};
286	clock_gettime(CLOCK_REALTIME, &ts);
287	if (cMillies != 0)
288	{
289	ts.tv_nsec += (cMillies % 1000) * 1000000;
290	ts.tv_sec += cMillies / 1000;
291	if (ts.tv_nsec >= 1000000000)
292	{
293	ts.tv_nsec -= 1000000000;
294	ts.tv_sec++;
295	}
296	}
297
298	/* take rwlock */
299	int rc = pthread_rwlock_timedrdlock(&pThis->RWLock, &ts);
300	RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_READ);
301	if (rc)
302	{
303	AssertMsg(rc == ETIMEDOUT, ("Failed read lock read-write sem %p, rc=%d.\n", hRWSem, rc));
304	return RTErrConvertFromErrno(rc);
305	}
306	#endif /* !RT_OS_DARWIN */
307	}
308
309	ASMAtomicIncU32(&pThis->cReaders);
310	#ifdef RTSEMRW_STRICT
311	RTLockValidatorRecSharedAddOwner(&pThis->ValidatorRead, hThreadSelf, pSrcPos);
312	#endif
313	return VINF_SUCCESS;
314	}
315
316
317	#undef RTSemRWRequestRead
318	RTDECL(int) RTSemRWRequestRead(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
319	{
320	#ifndef RTSEMRW_STRICT
321	return rtSemRWRequestRead(hRWSem, cMillies, NULL);
322	#else
323	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
324	return rtSemRWRequestRead(hRWSem, cMillies, &SrcPos);
325	#endif
326	}
327
328
329	RTDECL(int) RTSemRWRequestReadDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
330	{
331	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
332	return rtSemRWRequestRead(hRWSem, cMillies, &SrcPos);
333	}
334
335
336	#undef RTSemRWRequestReadNoResume
337	RTDECL(int) RTSemRWRequestReadNoResume(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
338	{
339	/* EINTR isn't returned by the wait functions we're using. */
340	#ifndef RTSEMRW_STRICT
341	return rtSemRWRequestRead(hRWSem, cMillies, NULL);
342	#else
343	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
344	return rtSemRWRequestRead(hRWSem, cMillies, &SrcPos);
345	#endif
346	}
347
348
349	RTDECL(int) RTSemRWRequestReadNoResumeDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
350	{
351	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
352	return rtSemRWRequestRead(hRWSem, cMillies, &SrcPos);
353	}
354
355
356	RTDECL(int) RTSemRWReleaseRead(RTSEMRW hRWSem)
357	{
358	/*
359	* Validate input.
360	*/
361	struct RTSEMRWINTERNAL *pThis = hRWSem;
362	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
363	AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
364	("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
365	VERR_INVALID_HANDLE);
366
367	/*
368	* Check if it's the writer.
369	*/
370	pthread_t Self = pthread_self();
371	pthread_t Writer;
372	ATOMIC_GET_PTHREAD_T(&pThis->Writer, &Writer);
373	if (Writer == Self)
374	{
375	AssertMsgReturn(pThis->cWriterReads > 0, ("pThis=%p\n", pThis), VERR_NOT_OWNER);
376	#ifdef RTSEMRW_STRICT
377	int rc9 = RTLockValidatorRecExclUnwindMixed(&pThis->ValidatorWrite, &pThis->ValidatorRead.Core);
378	if (RT_FAILURE(rc9))
379	return rc9;
380	#endif
381	pThis->cWriterReads--;
382	return VINF_SUCCESS;
383	}
384
385	/*
386	* Try unlock it.
387	*/
388	#ifdef RTSEMRW_STRICT
389	int rc9 = RTLockValidatorRecSharedCheckAndRelease(&pThis->ValidatorRead, RTThreadSelf());
390	if (RT_FAILURE(rc9))
391	return rc9;
392	#endif
393	#ifdef RT_OS_LINUX /* glibc (at least 2.8) may screw up when unlocking a lock we don't own. */
394	if (ASMAtomicReadU32(&pThis->cReaders) == 0)
395	{
396	AssertMsgFailed(("Not owner of %p\n", pThis));
397	return VERR_NOT_OWNER;
398	}
399	#endif
400	ASMAtomicDecU32(&pThis->cReaders);
401	int rc = pthread_rwlock_unlock(&pThis->RWLock);
402	if (rc)
403	{
404	ASMAtomicIncU32(&pThis->cReaders);
405	AssertMsgFailed(("Failed read unlock read-write sem %p, rc=%d.\n", hRWSem, rc));
406	return RTErrConvertFromErrno(rc);
407	}
408	return VINF_SUCCESS;
409	}
410
411
412	DECL_FORCE_INLINE(int) rtSemRWRequestWrite(RTSEMRW hRWSem, RTMSINTERVAL cMillies, PCRTLOCKVALSRCPOS pSrcPos)
413	{
414	/*
415	* Validate input.
416	*/
417	struct RTSEMRWINTERNAL *pThis = hRWSem;
418	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
419	AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
420	("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
421	VERR_INVALID_HANDLE);
422
423	/*
424	* Recursion?
425	*/
426	pthread_t Self = pthread_self();
427	pthread_t Writer;
428	ATOMIC_GET_PTHREAD_T(&pThis->Writer, &Writer);
429	if (Writer == Self)
430	{
431	#ifdef RTSEMRW_STRICT
432	int rc9 = RTLockValidatorRecExclRecursion(&pThis->ValidatorWrite, pSrcPos);
433	if (RT_FAILURE(rc9))
434	return rc9;
435	#endif
436	Assert(pThis->cWrites < INT32_MAX);
437	pThis->cWrites++;
438	return VINF_SUCCESS;
439	}
440
441	/*
442	* Try lock it.
443	*/
444	RTTHREAD hThreadSelf = NIL_RTTHREAD;
445	if (cMillies)
446	{
447	#ifdef RTSEMRW_STRICT
448	hThreadSelf = RTThreadSelfAutoAdopt();
449	int rc9 = RTLockValidatorRecExclCheckOrderAndBlocking(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, true,
450	cMillies, RTTHREADSTATE_RW_WRITE, true);
451	if (RT_FAILURE(rc9))
452	return rc9;
453	#else
454	hThreadSelf = RTThreadSelf();
455	RTThreadBlocking(hThreadSelf, RTTHREADSTATE_RW_WRITE, true);
456	#endif
457	}
458
459	if (cMillies == RT_INDEFINITE_WAIT)
460	{
461	/* take rwlock */
462	int rc = pthread_rwlock_wrlock(&pThis->RWLock);
463	RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_WRITE);
464	if (rc)
465	{
466	AssertMsgFailed(("Failed write lock read-write sem %p, rc=%d.\n", hRWSem, rc));
467	return RTErrConvertFromErrno(rc);
468	}
469	}
470	else
471	{
472	#ifdef RT_OS_DARWIN
473	AssertMsgFailed(("Not implemented on Darwin yet because of incomplete pthreads API."));
474	return VERR_NOT_IMPLEMENTED;
475	#else /* !RT_OS_DARWIN */
476	/*
477	* Get current time and calc end of wait time.
478	*/
479	struct timespec ts = {0,0};
480	clock_gettime(CLOCK_REALTIME, &ts);
481	if (cMillies != 0)
482	{
483	ts.tv_nsec += (cMillies % 1000) * 1000000;
484	ts.tv_sec += cMillies / 1000;
485	if (ts.tv_nsec >= 1000000000)
486	{
487	ts.tv_nsec -= 1000000000;
488	ts.tv_sec++;
489	}
490	}
491
492	/* take rwlock */
493	int rc = pthread_rwlock_timedwrlock(&pThis->RWLock, &ts);
494	RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_WRITE);
495	if (rc)
496	{
497	AssertMsg(rc == ETIMEDOUT, ("Failed read lock read-write sem %p, rc=%d.\n", hRWSem, rc));
498	return RTErrConvertFromErrno(rc);
499	}
500	#endif /* !RT_OS_DARWIN */
501	}
502
503	ATOMIC_SET_PTHREAD_T(&pThis->Writer, Self);
504	pThis->cWrites = 1;
505	Assert(!pThis->cReaders);
506	#ifdef RTSEMRW_STRICT
507	RTLockValidatorRecExclSetOwner(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, true);
508	#endif
509	return VINF_SUCCESS;
510	}
511
512
513	#undef RTSemRWRequestWrite
514	RTDECL(int) RTSemRWRequestWrite(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
515	{
516	#ifndef RTSEMRW_STRICT
517	return rtSemRWRequestWrite(hRWSem, cMillies, NULL);
518	#else
519	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
520	return rtSemRWRequestWrite(hRWSem, cMillies, &SrcPos);
521	#endif
522	}
523
524
525	RTDECL(int) RTSemRWRequestWriteDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
526	{
527	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
528	return rtSemRWRequestWrite(hRWSem, cMillies, &SrcPos);
529	}
530
531
532	#undef RTSemRWRequestWriteNoResume
533	RTDECL(int) RTSemRWRequestWriteNoResume(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
534	{
535	/* EINTR isn't returned by the wait functions we're using. */
536	#ifndef RTSEMRW_STRICT
537	return rtSemRWRequestWrite(hRWSem, cMillies, NULL);
538	#else
539	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
540	return rtSemRWRequestWrite(hRWSem, cMillies, &SrcPos);
541	#endif
542	}
543
544
545	RTDECL(int) RTSemRWRequestWriteNoResumeDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
546	{
547	/* EINTR isn't returned by the wait functions we're using. */
548	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
549	return rtSemRWRequestWrite(hRWSem, cMillies, &SrcPos);
550	}
551
552
553	RTDECL(int) RTSemRWReleaseWrite(RTSEMRW hRWSem)
554	{
555	/*
556	* Validate input.
557	*/
558	struct RTSEMRWINTERNAL *pThis = hRWSem;
559	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
560	AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
561	("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
562	VERR_INVALID_HANDLE);
563
564	/*
565	* Verify ownership and implement recursion.
566	*/
567	pthread_t Self = pthread_self();
568	pthread_t Writer;
569	ATOMIC_GET_PTHREAD_T(&pThis->Writer, &Writer);
570	AssertMsgReturn(Writer == Self, ("pThis=%p\n", pThis), VERR_NOT_OWNER);
571	AssertReturn(pThis->cWriterReads == 0 \|\| pThis->cWrites > 1, VERR_WRONG_ORDER);
572
573	if (pThis->cWrites > 1)
574	{
575	#ifdef RTSEMRW_STRICT
576	int rc9 = RTLockValidatorRecExclUnwind(&pThis->ValidatorWrite);
577	if (RT_FAILURE(rc9))
578	return rc9;
579	#endif
580	pThis->cWrites--;
581	return VINF_SUCCESS;
582	}
583
584	/*
585	* Try unlock it.
586	*/
587	#ifdef RTSEMRW_STRICT
588	int rc9 = RTLockValidatorRecExclReleaseOwner(&pThis->ValidatorWrite, true);
589	if (RT_FAILURE(rc9))
590	return rc9;
591	#endif
592
593	pThis->cWrites--;
594	ATOMIC_SET_PTHREAD_T(&pThis->Writer, (pthread_t)-1);
595	int rc = pthread_rwlock_unlock(&pThis->RWLock);
596	if (rc)
597	{
598	AssertMsgFailed(("Failed write unlock read-write sem %p, rc=%d.\n", hRWSem, rc));
599	return RTErrConvertFromErrno(rc);
600	}
601
602	return VINF_SUCCESS;
603	}
604
605
606	RTDECL(bool) RTSemRWIsWriteOwner(RTSEMRW hRWSem)
607	{
608	/*
609	* Validate input.
610	*/
611	struct RTSEMRWINTERNAL *pThis = hRWSem;
612	AssertPtrReturn(pThis, false);
613	AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
614	("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
615	false);
616
617	/*
618	* Check ownership.
619	*/
620	pthread_t Self = pthread_self();
621	pthread_t Writer;
622	ATOMIC_GET_PTHREAD_T(&pThis->Writer, &Writer);
623	return Writer == Self;
624	}
625
626
627	RTDECL(uint32_t) RTSemRWGetWriteRecursion(RTSEMRW hRWSem)
628	{
629	/*
630	* Validate input.
631	*/
632	struct RTSEMRWINTERNAL *pThis = hRWSem;
633	AssertPtrReturn(pThis, 0);
634	AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
635	("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
636	0);
637
638	/*
639	* Return the requested data.
640	*/
641	return pThis->cWrites;
642	}
643
644
645	RTDECL(uint32_t) RTSemRWGetWriterReadRecursion(RTSEMRW hRWSem)
646	{
647	/*
648	* Validate input.
649	*/
650	struct RTSEMRWINTERNAL *pThis = hRWSem;
651	AssertPtrReturn(pThis, 0);
652	AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
653	("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
654	0);
655
656	/*
657	* Return the requested data.
658	*/
659	return pThis->cWriterReads;
660	}
661
662
663	RTDECL(uint32_t) RTSemRWGetReadCount(RTSEMRW hRWSem)
664	{
665	/*
666	* Validate input.
667	*/
668	struct RTSEMRWINTERNAL *pThis = hRWSem;
669	AssertPtrReturn(pThis, 0);
670	AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
671	("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
672	0);
673
674	/*
675	* Return the requested data.
676	*/
677	return pThis->cReaders;
678	}
679

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source: vbox/trunk/src/VBox/Runtime/r3/posix/semrw-posix.cpp@ 25723

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