semrw-posix.cpp@ 18196

Last change on this file since 18196 was 8653, checked in by vboxsync, 17 years ago
Added RTSemRWIsWriteOwner, RTSemRWGetWriteRecursion and RTSemRWGetWriterReadRecursion.
Property svn:eol-style set to `native` Property svn:keywords set to `Id`
File size: 13.5 KB

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1	/* $Id: semrw-posix.cpp 8653 2008-05-07 12:31:30Z 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 <iprt/assert.h>
36	#include <iprt/alloc.h>
37	#include <iprt/thread.h>
38	#include <iprt/asm.h>
39	#include <iprt/err.h>
40
41	#include <errno.h>
42	#include <pthread.h>
43	#include <unistd.h>
44	#include <sys/time.h>
45
46	#include "internal/magics.h"
47	#include "internal/strict.h"
48
49
50	/*******************************************************************************
51	* Defined Constants And Macros *
52	*******************************************************************************/
53	/** @todo move this to r3/posix/something.h. */
54	#ifdef RT_OS_SOLARIS
55	# define ATOMIC_GET_PTHREAD_T(pvVar, pThread) ASMAtomicReadSize(pvVar, pThread)
56	# define ATOMIC_SET_PTHREAD_T(pvVar, pThread) ASMAtomicWriteSize(pvVar, pThread)
57	#else
58	AssertCompileSize(pthread_t, sizeof(void *));
59	# define ATOMIC_GET_PTHREAD_T(pvVar, pThread) do { (pThread) = (pthread_t)ASMAtomicReadPtr((void volatile *)pvVar); } while (0)
60	# define ATOMIC_SET_PTHREAD_T(pvVar, pThread) ASMAtomicWritePtr((void volatile )pvVar, (void *)pThread)
61	#endif
62
63
64	/*******************************************************************************
65	* Structures and Typedefs *
66	*******************************************************************************/
67	/** Posix internal representation of a read-write semaphore. */
68	struct RTSEMRWINTERNAL
69	{
70	/** The usual magic. (RTSEMRW_MAGIC) */
71	uint32_t u32Magic;
72	/* Alignment padding. */
73	uint32_t u32Padding;
74	/** Number of write recursions. */
75	uint32_t cWrites;
76	/** Number of read recursions by the writer. */
77	uint32_t cWriterReads;
78	/** The write owner of the lock. */
79	volatile pthread_t Writer;
80	/** pthread rwlock. */
81	pthread_rwlock_t RWLock;
82	};
83
84
85	RTDECL(int) RTSemRWCreate(PRTSEMRW pRWSem)
86	{
87	int rc;
88
89	/*
90	* Allocate handle.
91	*/
92	struct RTSEMRWINTERNAL pThis = (struct RTSEMRWINTERNAL )RTMemAlloc(sizeof(struct RTSEMRWINTERNAL));
93	if (pThis)
94	{
95	/*
96	* Create the rwlock.
97	*/
98	pthread_rwlockattr_t Attr;
99	rc = pthread_rwlockattr_init(&Attr);
100	if (!rc)
101	{
102	rc = pthread_rwlock_init(&pThis->RWLock, &Attr);
103	if (!rc)
104	{
105	pThis->u32Magic = RTSEMRW_MAGIC;
106	pThis->u32Padding = 0;
107	pThis->cWrites = 0;
108	pThis->cWriterReads = 0;
109	pThis->Writer = (pthread_t)-1;
110	*pRWSem = pThis;
111	return VINF_SUCCESS;
112	}
113	}
114
115	rc = RTErrConvertFromErrno(rc);
116	RTMemFree(pThis);
117	}
118	else
119	rc = VERR_NO_MEMORY;
120
121	return rc;
122	}
123
124
125	RTDECL(int) RTSemRWDestroy(RTSEMRW RWSem)
126	{
127	/*
128	* Validate input, nil handle is fine.
129	*/
130	if (RWSem == NIL_RTSEMRW)
131	return VINF_SUCCESS;
132	struct RTSEMRWINTERNAL *pThis = RWSem;
133	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
134	AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
135	("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
136	VERR_INVALID_HANDLE);
137	Assert(pThis->Writer == (pthread_t)-1);
138	Assert(!pThis->cWrites);
139	Assert(!pThis->cWriterReads);
140
141	/*
142	* Try destroy it.
143	*/
144	int rc = pthread_rwlock_destroy(&pThis->RWLock);
145	if (!rc)
146	{
147	pThis->u32Magic++;
148	RTMemFree(pThis);
149	rc = VINF_SUCCESS;
150	}
151	else
152	{
153	AssertMsgFailed(("Failed to destroy read-write sem %p, rc=%d.\n", RWSem, rc));
154	rc = RTErrConvertFromErrno(rc);
155	}
156
157	return rc;
158	}
159
160
161	RTDECL(int) RTSemRWRequestRead(RTSEMRW RWSem, unsigned cMillies)
162	{
163	/*
164	* Validate input.
165	*/
166	struct RTSEMRWINTERNAL *pThis = RWSem;
167	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
168	AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
169	("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
170	VERR_INVALID_HANDLE);
171
172	/*
173	* Check if it's the writer (implement write+read recursion).
174	*/
175	#ifdef RTSEMRW_STRICT
176	RTTHREAD ThreadSelf = RTThreadSelf();
177	#endif
178	pthread_t Self = pthread_self();
179	pthread_t Writer;
180	ATOMIC_GET_PTHREAD_T(&pThis->Writer, &Writer);
181	if (Writer == Self)
182	{
183	Assert(pThis->cWriterReads < INT32_MAX);
184	pThis->cWriterReads++;
185	#ifdef RTSEMRW_STRICT
186	if (ThreadSelf != NIL_RTTHREAD)
187	RTThreadReadLockInc(ThreadSelf);
188	#endif
189	return VINF_SUCCESS;
190	}
191
192	/*
193	* Try lock it.
194	*/
195	if (cMillies == RT_INDEFINITE_WAIT)
196	{
197	/* take rwlock */
198	int rc = pthread_rwlock_rdlock(&pThis->RWLock);
199	if (rc)
200	{
201	AssertMsgFailed(("Failed read lock read-write sem %p, rc=%d.\n", RWSem, rc));
202	return RTErrConvertFromErrno(rc);
203	}
204	}
205	else
206	{
207	#ifdef RT_OS_DARWIN
208	AssertMsgFailed(("Not implemented on Darwin yet because of incomplete pthreads API."));
209	return VERR_NOT_IMPLEMENTED;
210
211	#else /* !RT_OS_DARWIN */
212	/*
213	* Get current time and calc end of wait time.
214	*/
215	struct timespec ts = {0,0};
216	clock_gettime(CLOCK_REALTIME, &ts);
217	if (cMillies != 0)
218	{
219	ts.tv_nsec += (cMillies % 1000) * 1000000;
220	ts.tv_sec += cMillies / 1000;
221	if (ts.tv_nsec >= 1000000000)
222	{
223	ts.tv_nsec -= 1000000000;
224	ts.tv_sec++;
225	}
226	}
227
228	/* take rwlock */
229	int rc = pthread_rwlock_timedrdlock(&pThis->RWLock, &ts);
230	if (rc)
231	{
232	AssertMsg(rc == ETIMEDOUT, ("Failed read lock read-write sem %p, rc=%d.\n", RWSem, rc));
233	return RTErrConvertFromErrno(rc);
234	}
235	#endif /* !RT_OS_DARWIN */
236	}
237
238	#ifdef RTSEMRW_STRICT
239	if (ThreadSelf != NIL_RTTHREAD)
240	RTThreadReadLockInc(ThreadSelf);
241	#endif
242	return VINF_SUCCESS;
243	}
244
245
246	RTDECL(int) RTSemRWRequestReadNoResume(RTSEMRW RWSem, unsigned cMillies)
247	{
248	/* EINTR isn't returned by the wait functions we're using. */
249	return RTSemRWRequestRead(RWSem, cMillies);
250	}
251
252
253	RTDECL(int) RTSemRWReleaseRead(RTSEMRW RWSem)
254	{
255	/*
256	* Validate input.
257	*/
258	struct RTSEMRWINTERNAL *pThis = RWSem;
259	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
260	AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
261	("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
262	VERR_INVALID_HANDLE);
263
264	/*
265	* Check if it's the writer.
266	*/
267	#ifdef RTSEMRW_STRICT
268	RTTHREAD ThreadSelf = RTThreadSelf();
269	#endif
270	pthread_t Self = pthread_self();
271	pthread_t Writer;
272	ATOMIC_GET_PTHREAD_T(&pThis->Writer, &Writer);
273	if (Writer == Self)
274	{
275	AssertMsgReturn(pThis->cWriterReads > 0,
276	("pThis=%p\n", pThis), VERR_NOT_OWNER);
277	pThis->cWriterReads--;
278	#ifdef RTSEMRW_STRICT
279	if (ThreadSelf != NIL_RTTHREAD)
280	RTThreadReadLockDec(ThreadSelf);
281	#endif
282	return VINF_SUCCESS;
283	}
284
285	/*
286	* Try unlock it.
287	*/
288	int rc = pthread_rwlock_unlock(&pThis->RWLock);
289	if (rc)
290	{
291	AssertMsgFailed(("Failed read unlock read-write sem %p, rc=%d.\n", RWSem, rc));
292	return RTErrConvertFromErrno(rc);
293	}
294
295	#ifdef RTSEMRW_STRICT
296	if (ThreadSelf != NIL_RTTHREAD)
297	RTThreadReadLockDec(ThreadSelf);
298	#endif
299	return VINF_SUCCESS;
300	}
301
302
303	RTDECL(int) RTSemRWRequestWrite(RTSEMRW RWSem, unsigned cMillies)
304	{
305	/*
306	* Validate input.
307	*/
308	struct RTSEMRWINTERNAL *pThis = RWSem;
309	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
310	AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
311	("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
312	VERR_INVALID_HANDLE);
313
314	/*
315	* Recursion?
316	*/
317	pthread_t Self = pthread_self();
318	pthread_t Writer;
319	ATOMIC_GET_PTHREAD_T(&pThis->Writer, &Writer);
320	if (Writer == Self)
321	{
322	Assert(pThis->cWrites < INT32_MAX);
323	pThis->cWrites++;
324	return VINF_SUCCESS;
325	}
326
327	/*
328	* Try lock it.
329	*/
330	if (cMillies == RT_INDEFINITE_WAIT)
331	{
332	/* take rwlock */
333	int rc = pthread_rwlock_wrlock(&pThis->RWLock);
334	if (rc)
335	{
336	AssertMsgFailed(("Failed write lock read-write sem %p, rc=%d.\n", RWSem, rc));
337	return RTErrConvertFromErrno(rc);
338	}
339	}
340	else
341	{
342	#ifdef RT_OS_DARWIN
343	AssertMsgFailed(("Not implemented on Darwin yet because of incomplete pthreads API."));
344	return VERR_NOT_IMPLEMENTED;
345	#else /* !RT_OS_DARWIN */
346	/*
347	* Get current time and calc end of wait time.
348	*/
349	struct timespec ts = {0,0};
350	clock_gettime(CLOCK_REALTIME, &ts);
351	if (cMillies != 0)
352	{
353	ts.tv_nsec += (cMillies % 1000) * 1000000;
354	ts.tv_sec += cMillies / 1000;
355	if (ts.tv_nsec >= 1000000000)
356	{
357	ts.tv_nsec -= 1000000000;
358	ts.tv_sec++;
359	}
360	}
361
362	/* take rwlock */
363	int rc = pthread_rwlock_timedwrlock(&pThis->RWLock, &ts);
364	if (rc)
365	{
366	AssertMsg(rc == ETIMEDOUT, ("Failed read lock read-write sem %p, rc=%d.\n", RWSem, rc));
367	return RTErrConvertFromErrno(rc);
368	}
369	#endif /* !RT_OS_DARWIN */
370	}
371
372	ATOMIC_SET_PTHREAD_T(&pThis->Writer, Self);
373	pThis->cWrites = 1;
374	#ifdef RTSEMRW_STRICT
375	RTTHREAD ThreadSelf = RTThreadSelf();
376	if (ThreadSelf != NIL_RTTHREAD)
377	RTThreadWriteLockInc(ThreadSelf);
378	#endif
379	return VINF_SUCCESS;
380	}
381
382
383	RTDECL(int) RTSemRWRequestWriteNoResume(RTSEMRW RWSem, unsigned cMillies)
384	{
385	/* EINTR isn't returned by the wait functions we're using. */
386	return RTSemRWRequestWrite(RWSem, cMillies);
387	}
388
389
390	RTDECL(int) RTSemRWReleaseWrite(RTSEMRW RWSem)
391	{
392	/*
393	* Validate input.
394	*/
395	struct RTSEMRWINTERNAL *pThis = RWSem;
396	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
397	AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
398	("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
399	VERR_INVALID_HANDLE);
400
401	/*
402	* Verify ownership and implement recursion.
403	*/
404	pthread_t Self = pthread_self();
405	pthread_t Writer;
406	ATOMIC_GET_PTHREAD_T(&pThis->Writer, &Writer);
407	AssertMsgReturn(Writer == Self, ("pThis=%p\n", pThis), VERR_NOT_OWNER);
408	pThis->cWrites--;
409	if (pThis->cWrites)
410	return VINF_SUCCESS;
411	AssertReturn(!pThis->cWriterReads, VERR_WRONG_ORDER);
412
413	/*
414	* Try unlock it.
415	*/
416	ATOMIC_SET_PTHREAD_T(&pThis->Writer, (pthread_t)-1);
417	int rc = pthread_rwlock_unlock(&pThis->RWLock);
418	if (rc)
419	{
420	AssertMsgFailed(("Failed write unlock read-write sem %p, rc=%d.\n", RWSem, rc));
421	return RTErrConvertFromErrno(rc);
422	}
423
424	#ifdef RTSEMRW_STRICT
425	RTTHREAD ThreadSelf = RTThreadSelf();
426	if (ThreadSelf != NIL_RTTHREAD)
427	RTThreadWriteLockDec(ThreadSelf);
428	#endif
429	return VINF_SUCCESS;
430	}
431
432
433	RTDECL(bool) RTSemRWIsWriteOwner(RTSEMRW RWSem)
434	{
435	/*
436	* Validate input.
437	*/
438	struct RTSEMRWINTERNAL *pThis = RWSem;
439	AssertPtrReturn(pThis, false);
440	AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
441	("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
442	false);
443
444	/*
445	* Check ownership.
446	*/
447	pthread_t Self = pthread_self();
448	pthread_t Writer;
449	ATOMIC_GET_PTHREAD_T(&pThis->Writer, &Writer);
450	return Writer == Self;
451	}
452
453
454	RTDECL(uint32_t) RTSemRWGetWriteRecursion(RTSEMRW RWSem)
455	{
456	/*
457	* Validate input.
458	*/
459	struct RTSEMRWINTERNAL *pThis = RWSem;
460	AssertPtrReturn(pThis, 0);
461	AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
462	("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
463	0);
464
465	/*
466	* Return the requested data.
467	*/
468	return pThis->cWrites;
469	}
470
471
472	RTDECL(uint32_t) RTSemRWGetWriterReadRecursion(RTSEMRW RWSem)
473	{
474	/*
475	* Validate input.
476	*/
477	struct RTSEMRWINTERNAL *pThis = RWSem;
478	AssertPtrReturn(pThis, 0);
479	AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
480	("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
481	0);
482
483	/*
484	* Return the requested data.
485	*/
486	return pThis->cWriterReads;
487	}

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source: vbox/trunk/src/VBox/Runtime/r3/posix/semrw-posix.cpp@ 18196

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