RTDECL(int) RTSemRWReleaseRead(RTSEMRW hRWSem)
{
/*
* 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.
*/
pthread_t Self = pthread_self();
pthread_t Writer;
ATOMIC_GET_PTHREAD_T(&pThis->Writer, &Writer);
if (Writer == Self)
{
AssertMsgReturn(pThis->cWriterReads > 0, ("pThis=%p\n", pThis), VERR_NOT_OWNER);
#ifdef RTSEMRW_STRICT
int rc9 = RTLockValidatorRecExclUnwindMixed(&pThis->ValidatorWrite, &pThis->ValidatorRead.Core);
if (RT_FAILURE(rc9))
return rc9;
#endif
pThis->cWriterReads--;
return VINF_SUCCESS;
}
/*
* Try unlock it.
*/
#ifdef RTSEMRW_STRICT
int rc9 = RTLockValidatorRecSharedCheckAndRelease(&pThis->ValidatorRead, RTThreadSelf());
if (RT_FAILURE(rc9))
return rc9;
#endif
#ifdef RT_OS_LINUX /* glibc (at least 2.8) may screw up when unlocking a lock we don't own. */
if (ASMAtomicReadU32(&pThis->cReaders) == 0)
{
AssertMsgFailed(("Not owner of %p\n", pThis));
return VERR_NOT_OWNER;
}
#endif
ASMAtomicDecU32(&pThis->cReaders);
int rc = pthread_rwlock_unlock(&pThis->RWLock);
if (rc)
{
ASMAtomicIncU32(&pThis->cReaders);
AssertMsgFailed(("Failed read unlock read-write sem %p, rc=%d.\n", hRWSem, rc));
return RTErrConvertFromErrno(rc);
}
return VINF_SUCCESS;
}
RTDECL(int) RTSemRWReleaseRead(RTSEMRW hRWSem)
{
struct RTSEMRWINTERNAL *pThis = hRWSem;
/*
* Validate handle.
*/
AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
/*
* Take critsect.
*/
int rc = RTCritSectEnter(&pThis->CritSect);
if (RT_SUCCESS(rc))
{
if (pThis->hWriter == NIL_RTNATIVETHREAD)
{
#ifdef RTSEMRW_STRICT
rc = RTLockValidatorRecSharedCheckAndRelease(&pThis->ValidatorRead, NIL_RTTHREAD);
if (RT_SUCCESS(rc))
#endif
{
if (RT_LIKELY(pThis->cReads > 0))
{
pThis->cReads--;
/* Kick off a writer if appropriate. */
if ( pThis->cWritesWaiting > 0
&& !pThis->cReads)
{
rc = RTSemEventSignal(pThis->WriteEvent);
AssertMsgRC(rc, ("Failed to signal writers on rwsem %p, rc=%Rrc\n", hRWSem, rc));
}
}
else
{
AssertFailed();
rc = VERR_NOT_OWNER;
}
}
}
else
{
RTNATIVETHREAD hNativeSelf = pThis->CritSect.NativeThreadOwner;
if (pThis->hWriter == hNativeSelf)
{
if (pThis->cWriterReads > 0)
{
#ifdef RTSEMRW_STRICT
rc = RTLockValidatorRecExclUnwindMixed(&pThis->ValidatorWrite, &pThis->ValidatorRead.Core);
if (RT_SUCCESS(rc))
#endif
{
pThis->cWriterReads--;
}
}
else
{
AssertFailed();
rc = VERR_NOT_OWNER;
}
}
else
{
AssertFailed();
rc = VERR_NOT_OWNER;
}
}
RTCritSectLeave(&pThis->CritSect);
}
else
AssertMsgFailed(("RTCritSectEnter failed on rwsem %p, rc=%Rrc\n", hRWSem, rc));
return rc;
}