/**
* Try adjust the time using adjtime or similar.
*
* @returns true on success, false on failure.
*
* @param pDrift The time adjustment.
*/
static void vgsvcTimeSyncSet(PCRTTIMESPEC pDrift)
{
/*
* Query the current time, adjust it by adding the drift and set it.
*/
RTTIMESPEC NewGuestTime;
int rc = RTTimeSet(RTTimeSpecAdd(RTTimeNow(&NewGuestTime), pDrift));
if (RT_SUCCESS(rc))
{
/* Succeeded - reset the error count and log the change. */
g_cTimeSyncErrors = 0;
if (g_cVerbosity >= 1)
{
char sz[64];
RTTIME Time;
VGSvcVerbose(1, "time set to %s\n", RTTimeToString(RTTimeExplode(&Time, &NewGuestTime), sz, sizeof(sz)));
#ifdef DEBUG
RTTIMESPEC Tmp;
if (g_cVerbosity >= 3)
VGSvcVerbose(3, " now %s\n", RTTimeToString(RTTimeExplode(&Time, RTTimeNow(&Tmp)), sz, sizeof(sz)));
#endif
}
}
else if (g_cTimeSyncErrors++ < 10)
VGSvcError("vgsvcTimeSyncSet: RTTimeSet(%RDtimespec) failed: %Rrc\n", &NewGuestTime, rc);
}
/**
* Converts a time spec to a ISO date string.
*
* @returns psz on success.
* @returns NULL on buffer underflow.
* @param pTime The time spec.
* @param psz Where to store the string.
* @param cb The size of the buffer.
*/
RTDECL(char *) RTTimeSpecToString(PCRTTIMESPEC pTime, char *psz, size_t cb)
{
RTTIME Time;
return RTTimeToString(RTTimeExplode(&Time, pTime), psz, cb);
}
/**
* @interface_method_impl{VBOXSERVICE,pfnWorker}
*/
DECLCALLBACK(int) vgsvcTimeSyncWorker(bool volatile *pfShutdown)
{
RTTIME Time;
char sz[64];
int rc = VINF_SUCCESS;
/*
* Tell the control thread that it can continue spawning services.
*/
RTThreadUserSignal(RTThreadSelf());
/*
* The Work Loop.
*/
for (;;)
{
/*
* Try get a reliable time reading.
*/
int cTries = 3;
do
{
/* query it. */
RTTIMESPEC GuestNow0, GuestNow, HostNow;
RTTimeNow(&GuestNow0);
int rc2 = VbglR3GetHostTime(&HostNow);
if (RT_FAILURE(rc2))
{
if (g_cTimeSyncErrors++ < 10)
VGSvcError("vgsvcTimeSyncWorker: VbglR3GetHostTime failed; rc2=%Rrc\n", rc2);
break;
}
RTTimeNow(&GuestNow);
/* calc latency and check if it's ok. */
RTTIMESPEC GuestElapsed = GuestNow;
RTTimeSpecSub(&GuestElapsed, &GuestNow0);
if ((uint32_t)RTTimeSpecGetMilli(&GuestElapsed) < g_TimeSyncMaxLatency)
{
/*
* Set the time once after we were restored.
* (Of course only if the drift is bigger than MinAdjust)
*/
uint32_t TimeSyncSetThreshold = g_TimeSyncSetThreshold;
if (g_fTimeSyncSetOnRestore)
{
uint64_t idNewSession = g_idTimeSyncSession;
VbglR3GetSessionId(&idNewSession);
if (idNewSession != g_idTimeSyncSession)
{
VGSvcVerbose(3, "vgsvcTimeSyncWorker: The VM session ID changed, forcing resync.\n");
TimeSyncSetThreshold = 0;
g_idTimeSyncSession = idNewSession;
}
}
/*
* Calculate the adjustment threshold and the current drift.
*/
uint32_t MinAdjust = RTTimeSpecGetMilli(&GuestElapsed) * g_TimeSyncLatencyFactor;
if (MinAdjust < g_TimeSyncMinAdjust)
MinAdjust = g_TimeSyncMinAdjust;
RTTIMESPEC Drift = HostNow;
RTTimeSpecSub(&Drift, &GuestNow);
if (RTTimeSpecGetMilli(&Drift) < 0)
MinAdjust += g_TimeSyncMinAdjust; /* extra buffer against moving time backwards. */
RTTIMESPEC AbsDrift = Drift;
RTTimeSpecAbsolute(&AbsDrift);
if (g_cVerbosity >= 3)
{
VGSvcVerbose(3, "vgsvcTimeSyncWorker: Host: %s (MinAdjust: %RU32 ms)\n",
RTTimeToString(RTTimeExplode(&Time, &HostNow), sz, sizeof(sz)), MinAdjust);
VGSvcVerbose(3, "vgsvcTimeSyncWorker: Guest: - %s => %RDtimespec drift\n",
RTTimeToString(RTTimeExplode(&Time, &GuestNow), sz, sizeof(sz)), &Drift);
}
uint32_t AbsDriftMilli = RTTimeSpecGetMilli(&AbsDrift);
if (AbsDriftMilli > MinAdjust)
{
/*
* Ok, the drift is above the threshold.
*
* Try a gradual adjustment first, if that fails or the drift is
* too big, fall back on just setting the time.
*/
if ( AbsDriftMilli > TimeSyncSetThreshold
|| g_fTimeSyncSetNext
|| !vgsvcTimeSyncAdjust(&Drift))
{
vgsvcTimeSyncCancelAdjust();
vgsvcTimeSyncSet(&Drift);
}
}
else
vgsvcTimeSyncCancelAdjust();
break;
}
VGSvcVerbose(3, "vgsvcTimeSyncWorker: %RDtimespec: latency too high (%RDtimespec) sleeping 1s\n", GuestElapsed);
RTThreadSleep(1000);
} while (--cTries > 0);
/* Clear the set-next/set-start flag. */
g_fTimeSyncSetNext = false;
/*
* Block for a while.
*
* The event semaphore takes care of ignoring interruptions and it
* allows us to implement service wakeup later.
*/
if (*pfShutdown)
break;
int rc2 = RTSemEventMultiWait(g_TimeSyncEvent, g_TimeSyncInterval);
if (*pfShutdown)
break;
if (rc2 != VERR_TIMEOUT && RT_FAILURE(rc2))
{
VGSvcError("vgsvcTimeSyncWorker: RTSemEventMultiWait failed; rc2=%Rrc\n", rc2);
rc = rc2;
break;
}
}
vgsvcTimeSyncCancelAdjust();
RTSemEventMultiDestroy(g_TimeSyncEvent);
g_TimeSyncEvent = NIL_RTSEMEVENTMULTI;
return rc;
}
