DECL_FORCE_INLINE(int) rtSemRWRequestRead(RTSEMRW hRWSem, RTMSINTERVAL cMillies, PCRTLOCKVALSRCPOS pSrcPos) { /* * Validate input. */ struct RTSEMRWINTERNAL *pThis = hRWSem; AssertPtrReturn(pThis, VERR_INVALID_HANDLE); AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC, ("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic), VERR_INVALID_HANDLE); /* * Check if it's the writer (implement write+read recursion). */ pthread_t Self = pthread_self(); pthread_t Writer; ATOMIC_GET_PTHREAD_T(&pThis->Writer, &Writer); if (Writer == Self) { #ifdef RTSEMRW_STRICT int rc9 = RTLockValidatorRecExclRecursionMixed(&pThis->ValidatorWrite, &pThis->ValidatorRead.Core, pSrcPos); if (RT_FAILURE(rc9)) return rc9; #endif Assert(pThis->cWriterReads < INT32_MAX); pThis->cWriterReads++; return VINF_SUCCESS; } /* * Try lock it. */ RTTHREAD hThreadSelf = NIL_RTTHREAD; if (cMillies > 0) { #ifdef RTSEMRW_STRICT hThreadSelf = RTThreadSelfAutoAdopt(); int rc9 = RTLockValidatorRecSharedCheckOrderAndBlocking(&pThis->ValidatorRead, hThreadSelf, pSrcPos, true, cMillies, RTTHREADSTATE_RW_READ, true); if (RT_FAILURE(rc9)) return rc9; #else hThreadSelf = RTThreadSelf(); RTThreadBlocking(hThreadSelf, RTTHREADSTATE_RW_READ, true); #endif } if (cMillies == RT_INDEFINITE_WAIT) { /* take rwlock */ int rc = pthread_rwlock_rdlock(&pThis->RWLock); RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_READ); if (rc) { AssertMsgFailed(("Failed read lock read-write sem %p, rc=%d.\n", hRWSem, rc)); return RTErrConvertFromErrno(rc); } } else { #ifdef RT_OS_DARWIN AssertMsgFailed(("Not implemented on Darwin yet because of incomplete pthreads API.")); return VERR_NOT_IMPLEMENTED; #else /* !RT_OS_DARWIN */ /* * Get current time and calc end of wait time. */ struct timespec ts = {0,0}; clock_gettime(CLOCK_REALTIME, &ts); if (cMillies != 0) { ts.tv_nsec += (cMillies % 1000) * 1000000; ts.tv_sec += cMillies / 1000; if (ts.tv_nsec >= 1000000000) { ts.tv_nsec -= 1000000000; ts.tv_sec++; } } /* take rwlock */ int rc = pthread_rwlock_timedrdlock(&pThis->RWLock, &ts); RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_READ); if (rc) { AssertMsg(rc == ETIMEDOUT, ("Failed read lock read-write sem %p, rc=%d.\n", hRWSem, rc)); return RTErrConvertFromErrno(rc); } #endif /* !RT_OS_DARWIN */ } ASMAtomicIncU32(&pThis->cReaders); #ifdef RTSEMRW_STRICT RTLockValidatorRecSharedAddOwner(&pThis->ValidatorRead, hThreadSelf, pSrcPos); #endif return VINF_SUCCESS; }
DECL_FORCE_INLINE(int) rtSemRWRequestRead(RTSEMRW hRWSem, RTMSINTERVAL cMillies, bool fInterruptible, PCRTLOCKVALSRCPOS pSrcPos) { /* * Validate handle. */ struct RTSEMRWINTERNAL *pThis = hRWSem; AssertPtrReturn(pThis, VERR_INVALID_HANDLE); AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE); RTMSINTERVAL cMilliesInitial = cMillies; uint64_t tsStart = 0; if (cMillies != RT_INDEFINITE_WAIT && cMillies != 0) tsStart = RTTimeNanoTS(); #ifdef RTSEMRW_STRICT RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt(); if (cMillies > 0) { int rc9; if (pThis->hWriter != NIL_RTTHREAD && pThis->hWriter == RTThreadNativeSelf()) rc9 = RTLockValidatorRecExclCheckOrder(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, cMillies); else rc9 = RTLockValidatorRecSharedCheckOrder(&pThis->ValidatorRead, hThreadSelf, pSrcPos, cMillies); if (RT_FAILURE(rc9)) return rc9; } #endif /* * Take critsect. */ int rc = RTCritSectEnter(&pThis->CritSect); if (RT_FAILURE(rc)) { AssertMsgFailed(("RTCritSectEnter failed on rwsem %p, rc=%Rrc\n", hRWSem, rc)); return rc; } /* * Check if the state of affairs allows read access. * Do not block further readers if there is a writer waiting, as * that will break/deadlock reader recursion. */ if ( pThis->hWriter == NIL_RTNATIVETHREAD #if 0 && ( !pThis->cWritesWaiting || pThis->cReads) #endif ) { pThis->cReads++; Assert(pThis->cReads > 0); #ifdef RTSEMRW_STRICT RTLockValidatorRecSharedAddOwner(&pThis->ValidatorRead, hThreadSelf, pSrcPos); #endif RTCritSectLeave(&pThis->CritSect); return VINF_SUCCESS; } RTNATIVETHREAD hNativeSelf = pThis->CritSect.NativeThreadOwner; if (pThis->hWriter == hNativeSelf) { #ifdef RTSEMRW_STRICT int rc9 = RTLockValidatorRecExclRecursionMixed(&pThis->ValidatorWrite, &pThis->ValidatorRead.Core, pSrcPos); if (RT_FAILURE(rc9)) { RTCritSectLeave(&pThis->CritSect); return rc9; } #endif pThis->cWriterReads++; Assert(pThis->cWriterReads > 0); RTCritSectLeave(&pThis->CritSect); return VINF_SUCCESS; } RTCritSectLeave(&pThis->CritSect); /* * Wait till it's ready for reading. */ if (cMillies == 0) return VERR_TIMEOUT; #ifndef RTSEMRW_STRICT RTTHREAD hThreadSelf = RTThreadSelf(); #endif for (;;) { if (cMillies != RT_INDEFINITE_WAIT) { int64_t tsDelta = RTTimeNanoTS() - tsStart; if (tsDelta >= 1000000) { tsDelta /= 1000000; if ((uint64_t)tsDelta < cMilliesInitial) cMilliesInitial = (RTMSINTERVAL)tsDelta; else cMilliesInitial = 1; } } #ifdef RTSEMRW_STRICT rc = RTLockValidatorRecSharedCheckBlocking(&pThis->ValidatorRead, hThreadSelf, pSrcPos, true, cMillies, RTTHREADSTATE_RW_READ, false); if (RT_FAILURE(rc)) break; #else RTThreadBlocking(hThreadSelf, RTTHREADSTATE_RW_READ, false); #endif int rcWait; if (fInterruptible) rcWait = rc = RTSemEventMultiWaitNoResume(pThis->ReadEvent, cMillies); else rcWait = rc = RTSemEventMultiWait(pThis->ReadEvent, cMillies); RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_READ); if (RT_FAILURE(rc) && rc != VERR_TIMEOUT) /* handle timeout below */ { AssertMsgRC(rc, ("RTSemEventMultiWait failed on rwsem %p, rc=%Rrc\n", hRWSem, rc)); break; } if (pThis->u32Magic != RTSEMRW_MAGIC) { rc = VERR_SEM_DESTROYED; break; } /* * Re-take critsect and repeat the check we did before the loop. */ rc = RTCritSectEnter(&pThis->CritSect); if (RT_FAILURE(rc)) { AssertMsgFailed(("RTCritSectEnter failed on rwsem %p, rc=%Rrc\n", hRWSem, rc)); break; } if ( pThis->hWriter == NIL_RTNATIVETHREAD #if 0 && ( !pThis->cWritesWaiting || pThis->cReads) #endif ) { pThis->cReads++; Assert(pThis->cReads > 0); #ifdef RTSEMRW_STRICT RTLockValidatorRecSharedAddOwner(&pThis->ValidatorRead, hThreadSelf, pSrcPos); #endif RTCritSectLeave(&pThis->CritSect); return VINF_SUCCESS; } RTCritSectLeave(&pThis->CritSect); /* * Quit if the wait already timed out. */ if (rcWait == VERR_TIMEOUT) { rc = VERR_TIMEOUT; break; } } /* failed */ return rc; }