semevent-linux.cpp@ 62584

Last change on this file since 62584 was 62477, checked in by vboxsync, 8 years ago
(C) 2016
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1	/* $Id: semevent-linux.cpp 62477 2016-07-22 18:27:37Z vboxsync $ */
2	/** @file
3	* IPRT - Event Semaphore, Linux (2.6.x+).
4	*/
5
6	/*
7	* Copyright (C) 2006-2016 Oracle Corporation
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
27	#include <features.h>
28	#if __GLIBC_PREREQ(2,6) && !defined(IPRT_WITH_FUTEX_BASED_SEMS)
29
30	/*
31	* glibc 2.6 fixed a serious bug in the mutex implementation. We wrote this
32	* linux specific event semaphores code in order to work around the bug. We
33	* will fall back on the pthread-based implementation if glibc is known to
34	* contain the bug fix.
35	*
36	* The external reference to epoll_pwait is a hack which prevents that we link
37	* against glibc < 2.6.
38	*/
39	#include "../posix/semevent-posix.cpp"
40	asm volatile (".global epoll_pwait");
41
42	#else /* glibc < 2.6 */
43
44
45	/*********************************************************************************************************************************
46	* Header Files *
47	*********************************************************************************************************************************/
48	#include <iprt/semaphore.h>
49	#include "internal/iprt.h"
50
51	#include <iprt/asm.h>
52	#include <iprt/assert.h>
53	#include <iprt/err.h>
54	#include <iprt/lockvalidator.h>
55	#include <iprt/mem.h>
56	#include <iprt/time.h>
57	#include "internal/magics.h"
58	#include "internal/mem.h"
59	#include "internal/strict.h"
60
61	#include <errno.h>
62	#include <limits.h>
63	#include <pthread.h>
64	#include <unistd.h>
65	#include <sys/time.h>
66	#include <sys/syscall.h>
67	#if 0 /* With 2.6.17 futex.h has become C++ unfriendly. */
68	# include <linux/futex.h>
69	#else
70	# define FUTEX_WAIT 0
71	# define FUTEX_WAKE 1
72	#endif
73
74
75	/*********************************************************************************************************************************
76	* Structures and Typedefs *
77	*********************************************************************************************************************************/
78	/**
79	* Linux (single wakup) event semaphore.
80	*/
81	struct RTSEMEVENTINTERNAL
82	{
83	/** Magic value. */
84	intptr_t volatile iMagic;
85	/** The futex state variable.
86	* 0 means not signalled.
87	1 means signalled. */
88	uint32_t volatile fSignalled;
89	/** The number of waiting threads */
90	int32_t volatile cWaiters;
91	#ifdef RTSEMEVENT_STRICT
92	/** Signallers. */
93	RTLOCKVALRECSHRD Signallers;
94	/** Indicates that lock validation should be performed. */
95	bool volatile fEverHadSignallers;
96	#endif
97	/** The creation flags. */
98	uint32_t fFlags;
99	};
100
101
102	/**
103	* Wrapper for the futex syscall.
104	*/
105	static long sys_futex(uint32_t volatile uaddr, int op, int val, struct timespec utime, int32_t *uaddr2, int val3)
106	{
107	errno = 0;
108	long rc = syscall(__NR_futex, uaddr, op, val, utime, uaddr2, val3);
109	if (rc < 0)
110	{
111	Assert(rc == -1);
112	rc = -errno;
113	}
114	return rc;
115	}
116
117
118
119	RTDECL(int) RTSemEventCreate(PRTSEMEVENT phEventSem)
120	{
121	return RTSemEventCreateEx(phEventSem, 0 /fFlags/, NIL_RTLOCKVALCLASS, NULL);
122	}
123
124
125	RTDECL(int) RTSemEventCreateEx(PRTSEMEVENT phEventSem, uint32_t fFlags, RTLOCKVALCLASS hClass, const char *pszNameFmt, ...)
126	{
127	AssertReturn(!(fFlags & ~(RTSEMEVENT_FLAGS_NO_LOCK_VAL \| RTSEMEVENT_FLAGS_BOOTSTRAP_HACK)), VERR_INVALID_PARAMETER);
128	Assert(!(fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK) \|\| (fFlags & RTSEMEVENT_FLAGS_NO_LOCK_VAL));
129
130	/*
131	* Allocate semaphore handle.
132	*/
133	struct RTSEMEVENTINTERNAL *pThis;
134	if (!(fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK))
135	pThis = (struct RTSEMEVENTINTERNAL *)RTMemAlloc(sizeof(struct RTSEMEVENTINTERNAL));
136	else
137	pThis = (struct RTSEMEVENTINTERNAL *)rtMemBaseAlloc(sizeof(struct RTSEMEVENTINTERNAL));
138	if (pThis)
139	{
140	pThis->iMagic = RTSEMEVENT_MAGIC;
141	pThis->cWaiters = 0;
142	pThis->fSignalled = 0;
143	pThis->fFlags = fFlags;
144	#ifdef RTSEMEVENT_STRICT
145	if (!pszNameFmt)
146	{
147	static uint32_t volatile s_iSemEventAnon = 0;
148	RTLockValidatorRecSharedInit(&pThis->Signallers, hClass, RTLOCKVAL_SUB_CLASS_ANY, pThis,
149	true /fSignaller/, !(fFlags & RTSEMEVENT_FLAGS_NO_LOCK_VAL),
150	"RTSemEvent-%u", ASMAtomicIncU32(&s_iSemEventAnon) - 1);
151	}
152	else
153	{
154	va_list va;
155	va_start(va, pszNameFmt);
156	RTLockValidatorRecSharedInitV(&pThis->Signallers, hClass, RTLOCKVAL_SUB_CLASS_ANY, pThis,
157	true /fSignaller/, !(fFlags & RTSEMEVENT_FLAGS_NO_LOCK_VAL),
158	pszNameFmt, va);
159	va_end(va);
160	}
161	pThis->fEverHadSignallers = false;
162	#endif
163
164	*phEventSem = pThis;
165	return VINF_SUCCESS;
166	}
167	return VERR_NO_MEMORY;
168	}
169
170
171	RTDECL(int) RTSemEventDestroy(RTSEMEVENT hEventSem)
172	{
173	/*
174	* Validate input.
175	*/
176	struct RTSEMEVENTINTERNAL *pThis = hEventSem;
177	if (pThis == NIL_RTSEMEVENT)
178	return VINF_SUCCESS;
179	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
180	AssertReturn(pThis->iMagic == RTSEMEVENT_MAGIC, VERR_INVALID_HANDLE);
181
182	/*
183	* Invalidate the semaphore and wake up anyone waiting on it.
184	*/
185	ASMAtomicXchgSize(&pThis->iMagic, RTSEMEVENT_MAGIC \| UINT32_C(0x80000000));
186	if (ASMAtomicXchgS32(&pThis->cWaiters, INT32_MIN / 2) > 0)
187	{
188	sys_futex(&pThis->fSignalled, FUTEX_WAKE, INT_MAX, NULL, NULL, 0);
189	usleep(1000);
190	}
191
192	/*
193	* Free the semaphore memory and be gone.
194	*/
195	#ifdef RTSEMEVENT_STRICT
196	RTLockValidatorRecSharedDelete(&pThis->Signallers);
197	#endif
198	if (!(pThis->fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK))
199	RTMemFree(pThis);
200	else
201	rtMemBaseFree(pThis);
202	return VINF_SUCCESS;
203	}
204
205
206	RTDECL(int) RTSemEventSignal(RTSEMEVENT hEventSem)
207	{
208	/*
209	* Validate input.
210	*/
211	struct RTSEMEVENTINTERNAL *pThis = hEventSem;
212	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
213	AssertReturn(pThis->iMagic == RTSEMEVENT_MAGIC, VERR_INVALID_HANDLE);
214
215	#ifdef RTSEMEVENT_STRICT
216	if (pThis->fEverHadSignallers)
217	{
218	int rc9 = RTLockValidatorRecSharedCheckSignaller(&pThis->Signallers, NIL_RTTHREAD);
219	if (RT_FAILURE(rc9))
220	return rc9;
221	}
222	#endif
223
224	ASMAtomicWriteU32(&pThis->fSignalled, 1);
225	if (ASMAtomicReadS32(&pThis->cWaiters) < 1)
226	return VINF_SUCCESS;
227
228	/* somebody is waiting, try wake up one of them. */
229	long cWoken = sys_futex(&pThis->fSignalled, FUTEX_WAKE, 1, NULL, NULL, 0);
230	if (RT_LIKELY(cWoken >= 0))
231	return VINF_SUCCESS;
232
233	if (RT_UNLIKELY(pThis->iMagic != RTSEMEVENT_MAGIC))
234	return VERR_SEM_DESTROYED;
235
236	return VERR_INVALID_PARAMETER;
237	}
238
239
240	static int rtSemEventWait(RTSEMEVENT hEventSem, RTMSINTERVAL cMillies, bool fAutoResume)
241	{
242	PCRTLOCKVALSRCPOS pSrcPos = NULL;
243
244	/*
245	* Validate input.
246	*/
247	struct RTSEMEVENTINTERNAL *pThis = hEventSem;
248	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
249	AssertReturn(pThis->iMagic == RTSEMEVENT_MAGIC, VERR_INVALID_HANDLE);
250
251	/*
252	* Quickly check whether it's signaled.
253	*/
254	/** @todo this isn't fair if someone is already waiting on it. They should
255	* have the first go at it!
256	* (ASMAtomicReadS32(&pThis->cWaiters) == 0 \|\| !cMillies) && ... */
257	if (ASMAtomicCmpXchgU32(&pThis->fSignalled, 0, 1))
258	return VINF_SUCCESS;
259
260	/*
261	* Convert the timeout value.
262	*/
263	struct timespec ts;
264	struct timespec *pTimeout = NULL;
265	uint64_t u64End = 0; /* shut up gcc */
266	if (cMillies != RT_INDEFINITE_WAIT)
267	{
268	if (!cMillies)
269	return VERR_TIMEOUT;
270	ts.tv_sec = cMillies / 1000;
271	ts.tv_nsec = (cMillies % 1000) * UINT32_C(1000000);
272	u64End = RTTimeSystemNanoTS() + cMillies * UINT64_C(1000000);
273	pTimeout = &ts;
274	}
275
276	ASMAtomicIncS32(&pThis->cWaiters);
277
278	/*
279	* The wait loop.
280	*/
281	#ifdef RTSEMEVENT_STRICT
282	RTTHREAD hThreadSelf = !(pThis->fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK)
283	? RTThreadSelfAutoAdopt()
284	: RTThreadSelf();
285	#else
286	RTTHREAD hThreadSelf = RTThreadSelf();
287	#endif
288	int rc = VINF_SUCCESS;
289	for (;;)
290	{
291	#ifdef RTSEMEVENT_STRICT
292	if (pThis->fEverHadSignallers)
293	{
294	rc = RTLockValidatorRecSharedCheckBlocking(&pThis->Signallers, hThreadSelf, pSrcPos, false,
295	cMillies, RTTHREADSTATE_EVENT, true);
296	if (RT_FAILURE(rc))
297	break;
298	}
299	#endif
300	RTThreadBlocking(hThreadSelf, RTTHREADSTATE_EVENT, true);
301	long lrc = sys_futex(&pThis->fSignalled, FUTEX_WAIT, 0, pTimeout, NULL, 0);
302	RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_EVENT);
303	if (RT_UNLIKELY(pThis->iMagic != RTSEMEVENT_MAGIC))
304	{
305	rc = VERR_SEM_DESTROYED;
306	break;
307	}
308
309	if (RT_LIKELY(lrc == 0 \|\| lrc == -EWOULDBLOCK))
310	{
311	/* successful wakeup or fSignalled > 0 in the meantime */
312	if (ASMAtomicCmpXchgU32(&pThis->fSignalled, 0, 1))
313	break;
314	}
315	else if (lrc == -ETIMEDOUT)
316	{
317	rc = VERR_TIMEOUT;
318	break;
319	}
320	else if (lrc == -EINTR)
321	{
322	if (!fAutoResume)
323	{
324	rc = VERR_INTERRUPTED;
325	break;
326	}
327	}
328	else
329	{
330	/* this shouldn't happen! */
331	AssertMsgFailed(("rc=%ld errno=%d\n", lrc, errno));
332	rc = RTErrConvertFromErrno(lrc);
333	break;
334	}
335	/* adjust the relative timeout */
336	if (pTimeout)
337	{
338	int64_t i64Diff = u64End - RTTimeSystemNanoTS();
339	if (i64Diff < 1000)
340	{
341	rc = VERR_TIMEOUT;
342	break;
343	}
344	ts.tv_sec = (uint64_t)i64Diff / UINT32_C(1000000000);
345	ts.tv_nsec = (uint64_t)i64Diff % UINT32_C(1000000000);
346	}
347	}
348
349	ASMAtomicDecS32(&pThis->cWaiters);
350	return rc;
351	}
352
353
354	RTDECL(int) RTSemEventWait(RTSEMEVENT hEventSem, RTMSINTERVAL cMillies)
355	{
356	int rc = rtSemEventWait(hEventSem, cMillies, true);
357	Assert(rc != VERR_INTERRUPTED);
358	Assert(rc != VERR_TIMEOUT \|\| cMillies != RT_INDEFINITE_WAIT);
359	return rc;
360	}
361
362
363	RTDECL(int) RTSemEventWaitNoResume(RTSEMEVENT hEventSem, RTMSINTERVAL cMillies)
364	{
365	return rtSemEventWait(hEventSem, cMillies, false);
366	}
367
368
369	RTDECL(void) RTSemEventSetSignaller(RTSEMEVENT hEventSem, RTTHREAD hThread)
370	{
371	#ifdef RTSEMEVENT_STRICT
372	struct RTSEMEVENTINTERNAL *pThis = hEventSem;
373	AssertPtrReturnVoid(pThis);
374	AssertReturnVoid(pThis->iMagic == RTSEMEVENT_MAGIC);
375
376	ASMAtomicWriteBool(&pThis->fEverHadSignallers, true);
377	RTLockValidatorRecSharedResetOwner(&pThis->Signallers, hThread, NULL);
378	#endif
379	}
380
381
382	RTDECL(void) RTSemEventAddSignaller(RTSEMEVENT hEventSem, RTTHREAD hThread)
383	{
384	#ifdef RTSEMEVENT_STRICT
385	struct RTSEMEVENTINTERNAL *pThis = hEventSem;
386	AssertPtrReturnVoid(pThis);
387	AssertReturnVoid(pThis->iMagic == RTSEMEVENT_MAGIC);
388
389	ASMAtomicWriteBool(&pThis->fEverHadSignallers, true);
390	RTLockValidatorRecSharedAddOwner(&pThis->Signallers, hThread, NULL);
391	#endif
392	}
393
394
395	RTDECL(void) RTSemEventRemoveSignaller(RTSEMEVENT hEventSem, RTTHREAD hThread)
396	{
397	#ifdef RTSEMEVENT_STRICT
398	struct RTSEMEVENTINTERNAL *pThis = hEventSem;
399	AssertPtrReturnVoid(pThis);
400	AssertReturnVoid(pThis->iMagic == RTSEMEVENT_MAGIC);
401
402	RTLockValidatorRecSharedRemoveOwner(&pThis->Signallers, hThread);
403	#endif
404	}
405
406	#endif /* glibc < 2.6 \|\| IPRT_WITH_FUTEX_BASED_SEMS */
407

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source: vbox/trunk/src/VBox/Runtime/r3/linux/semevent-linux.cpp@ 62584

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