VBoxServiceTimeSync.cpp revision 9fc464631dc4a68fbb5eb6419d61fbe91b6b16bd
/* $Id$ */
/** @file
* VBoxService - Guest Additions TimeSync Service.
*/
/*
* Copyright (C) 2007 Oracle Corporation
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* you can redistribute it and/or modify it under the terms of the GNU
* General Public License (GPL) as published by the Free Software
* Foundation, in version 2 as it comes in the "COPYING" file of the
* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
*/
/** @page pg_vboxservice_timesync The Time Sync Service
*
* The time sync service plays along with the Time Manager (TM) in the VMM
* to keep the guest time accurate using the host machine as reference.
* TM will try its best to make sure all timer ticks gets delivered so that
* there isn't normally any need to adjust the guest time.
*
* There are three normal (= acceptable) cases:
* -# When the service starts up. This is because ticks and such might
* be lost during VM and OS startup. (Need to figure out exactly why!)
* -# When the TM is unable to deliver all the ticks and swallows a
* backlog of ticks. The threshold for this is configurable with
* a default of 60 seconds.
* -# The time is adjusted on the host. This can be caused manually by
* the user or by some time sync daemon (NTP, LAN server, etc.).
*
* There are a number of very odd case where adjusting is needed. Here
* are some of them:
* -# Timer device emulation inaccuracies (like rounding).
* -# Inaccuracies in time source VirtualBox uses.
* -# The Guest and/or Host OS doesn't perform proper time keeping. This
* come about as a result of OS and/or hardware issues.
*
* The TM is our source for the host time and will make adjustments for
* current timer delivery lag. The simplistic approach taken by TM is to
* adjust the host time by the current guest timer delivery lag, meaning that
* if the guest is behind 1 second with PIT/RTC/++ ticks this should be reflected
* in the guest wall time as well.
*
* Now, there is any amount of trouble we can cause by changing the time.
* Most applications probably uses the wall time when they need to measure
* things. A walltime that is being juggled about every so often, even if just
* a little bit, could occasionally upset these measurements by for instance
* yielding negative results.
*
* This bottom line here is that the time sync service isn't really supposed
* to do anything and will try avoid having to do anything when possible.
*
* The implementation uses the latency it takes to query host time as the
* absolute maximum precision to avoid messing up under timer tick catchup
* and/or heavy host/guest load. (Rational is that a *lot* of stuff may happen
* on our way back from ring-3 and TM/VMMDev since we're taking the route
* thru the inner EM loop with it's force action processing.)
*
* But this latency has to be measured from our perspective, which means it
* could just as easily come out as 0. (OS/2 and Windows guest only updates
* the current time when the timer ticks for instance.) The good thing is
* that this isn't really a problem since we won't ever do anything unless
* the drift is noticeable.
*
* It now boils down to these three (configuration) factors:
* -# g_TimesyncMinAdjust - The minimum drift we will ever bother with.
* -# g_TimesyncLatencyFactor - The factor we multiply the latency by to
* calculate the dynamic minimum adjust factor.
* -# g_TimesyncMaxLatency - When to start discarding the data as utterly
* useless and take a rest (someone is too busy to give us good data).
* -# g_TimeSyncSetThreshold - The threshold at which we will just set the time
* instead of trying to adjust it (milliseconds).
*/
/*******************************************************************************
* Header Files *
*******************************************************************************/
#ifdef RT_OS_WINDOWS
# include <Windows.h>
# include <winbase.h> /** @todo r=bird: Why is this here? Windows.h should include winbase.h... */
#else
# include <unistd.h>
# include <errno.h>
# include <time.h>
# include <sys/time.h>
#endif
#include <iprt/thread.h>
#include <iprt/string.h>
#include <iprt/semaphore.h>
#include <iprt/time.h>
#include <iprt/assert.h>
#include <VBox/VBoxGuestLib.h>
#include "VBoxServiceInternal.h"
#include "VBoxServiceUtils.h"
/*******************************************************************************
* Global Variables *
*******************************************************************************/
/** The timesync interval (milliseconds). */
uint32_t g_TimeSyncInterval = 0;
/**
* @see pg_vboxservice_timesync
*
* @remark OS/2: There is either a 1 second resolution on the DosSetDateTime
* API or a but in the settimeofday implementation. Thus, don't
* bother unless there is at least a 1 second drift.
*/
#ifdef RT_OS_OS2
static uint32_t g_TimeSyncMinAdjust = 1000;
#else
static uint32_t g_TimeSyncMinAdjust = 100;
#endif
/** @see pg_vboxservice_timesync */
static uint32_t g_TimeSyncLatencyFactor = 8;
/** @see pg_vboxservice_timesync */
static uint32_t g_TimeSyncMaxLatency = 250;
/** @see pg_vboxservice_timesync */
static uint32_t g_TimeSyncSetThreshold = 20*60*1000;
/** Whether the next adjustment should just set the time instead of trying to
* adjust it. This is used to implement --timesync-set-start. */
static bool volatile g_fTimeSyncSetNext = false;
/** Whether to set the time when the VM was restored. */
static bool g_fTimeSyncSetOnRestore = true;
/** Current error count. Used to knowing when to bitch and when not to. */
static uint32_t g_cTimeSyncErrors = 0;
/** The semaphore we're blocking on. */
static RTSEMEVENTMULTI g_TimeSyncEvent = NIL_RTSEMEVENTMULTI;
/** The VM session ID. Changes whenever the VM is restored or reset. */
static uint64_t g_idTimeSyncSession;
#ifdef RT_OS_WINDOWS
/** Process token. */
static HANDLE g_hTokenProcess = NULL;
/** Old token privileges. */
static TOKEN_PRIVILEGES g_TkOldPrivileges;
/** Backup values for time adjustment. */
static DWORD g_dwWinTimeAdjustment;
static DWORD g_dwWinTimeIncrement;
static BOOL g_bWinTimeAdjustmentDisabled;
#endif
/** @copydoc VBOXSERVICE::pfnPreInit */
static DECLCALLBACK(int) VBoxServiceTimeSyncPreInit(void)
{
#ifdef VBOX_WITH_GUEST_PROPS
/** @todo Merge this function with VBoxServiceTimeSyncOption() to generalize
* the "command line args override guest property values" behavior. */
/*
* Read the service options from the VM's guest properties.
* Note that these options can be overridden by the command line options later.
*/
uint32_t uGuestPropSvcClientID;
int rc = VbglR3GuestPropConnect(&uGuestPropSvcClientID);
if (RT_FAILURE(rc))
{
if (rc == VERR_HGCM_SERVICE_NOT_FOUND) /* Host service is not available. */
{
VBoxServiceVerbose(0, "VMInfo: Guest property service is not available, skipping\n");
rc = VINF_SUCCESS;
}
else
VBoxServiceError("Failed to connect to the guest property service! Error: %Rrc\n", rc);
}
else
{
rc = VBoxServiceReadPropUInt32(uGuestPropSvcClientID, "/VirtualBox/GuestAdd/VBoxService/--timesync-interval",
&g_TimeSyncInterval, 50, UINT32_MAX - 1);
if ( RT_SUCCESS(rc)
|| rc == VERR_NOT_FOUND)
{
rc = VBoxServiceReadPropUInt32(uGuestPropSvcClientID, "/VirtualBox/GuestAdd/VBoxService/--timesync-min-adjust",
&g_TimeSyncMinAdjust, 0, 3600000);
}
if ( RT_SUCCESS(rc)
|| rc == VERR_NOT_FOUND)
{
rc = VBoxServiceReadPropUInt32(uGuestPropSvcClientID, "/VirtualBox/GuestAdd/VBoxService/--timesync-latency-factor",
&g_TimeSyncLatencyFactor, 1, 1024);
}
if ( RT_SUCCESS(rc)
|| rc == VERR_NOT_FOUND)
{
rc = VBoxServiceReadPropUInt32(uGuestPropSvcClientID, "/VirtualBox/GuestAdd/VBoxService/--timesync-max-latency",
&g_TimeSyncMaxLatency, 1, 3600000);
}
if ( RT_SUCCESS(rc)
|| rc == VERR_NOT_FOUND)
{
rc = VBoxServiceReadPropUInt32(uGuestPropSvcClientID, "/VirtualBox/GuestAdd/VBoxService/--timesync-set-threshold",
&g_TimeSyncSetThreshold, 0, 7*24*60*60*1000 /* a week */);
}
if ( RT_SUCCESS(rc)
|| rc == VERR_NOT_FOUND)
{
char *pszValue;
rc = VBoxServiceReadProp(uGuestPropSvcClientID, "/VirtualBox/GuestAdd/VBoxService/--timesync-set-start",
&pszValue, NULL /* ppszFlags */, NULL /* puTimestamp */);
if (RT_SUCCESS(rc))
{
g_fTimeSyncSetNext = true;
RTStrFree(pszValue);
}
}
if ( RT_SUCCESS(rc)
|| rc == VERR_NOT_FOUND)
{
uint32_t value;
rc = VBoxServiceReadPropUInt32(uGuestPropSvcClientID, "/VirtualBox/GuestAdd/VBoxService/--timesync-set-on-restore",
&value, 1, 1);
if (RT_SUCCESS(rc))
g_fTimeSyncSetOnRestore = !!value;
}
VbglR3GuestPropDisconnect(uGuestPropSvcClientID);
}
if (rc == VERR_NOT_FOUND) /* If a value is not found, don't be sad! */
rc = VINF_SUCCESS;
return rc;
#else
/* Nothing to do here yet. */
return VINF_SUCCESS;
#endif
}
/** @copydoc VBOXSERVICE::pfnOption */
static DECLCALLBACK(int) VBoxServiceTimeSyncOption(const char **ppszShort, int argc, char **argv, int *pi)
{
int rc = -1;
uint32_t value;
if (ppszShort)
/* no short options */;
else if (!strcmp(argv[*pi], "--timesync-interval"))
rc = VBoxServiceArgUInt32(argc, argv, "", pi,
&g_TimeSyncInterval, 50, UINT32_MAX - 1);
else if (!strcmp(argv[*pi], "--timesync-min-adjust"))
rc = VBoxServiceArgUInt32(argc, argv, "", pi,
&g_TimeSyncMinAdjust, 0, 3600000);
else if (!strcmp(argv[*pi], "--timesync-latency-factor"))
rc = VBoxServiceArgUInt32(argc, argv, "", pi,
&g_TimeSyncLatencyFactor, 1, 1024);
else if (!strcmp(argv[*pi], "--timesync-max-latency"))
rc = VBoxServiceArgUInt32(argc, argv, "", pi,
&g_TimeSyncMaxLatency, 1, 3600000);
else if (!strcmp(argv[*pi], "--timesync-set-threshold"))
rc = VBoxServiceArgUInt32(argc, argv, "", pi,
&g_TimeSyncSetThreshold, 0, 7*24*60*60*1000); /* a week */
else if (!strcmp(argv[*pi], "--timesync-set-start"))
{
g_fTimeSyncSetNext = true;
rc = VINF_SUCCESS;
}
else if (!strcmp(argv[*pi], "--timesync-set-on-restore"))
{
rc = VBoxServiceArgUInt32(argc, argv, "", pi, &value, 1, 1);
if (RT_SUCCESS(rc))
g_fTimeSyncSetOnRestore = !!value;
}
return rc;
}
/** @copydoc VBOXSERVICE::pfnInit */
static DECLCALLBACK(int) VBoxServiceTimeSyncInit(void)
{
/*
* If not specified, find the right interval default.
* Then create the event sem to block on.
*/
if (!g_TimeSyncInterval)
g_TimeSyncInterval = g_DefaultInterval * 1000;
if (!g_TimeSyncInterval)
g_TimeSyncInterval = 10 * 1000;
VbglR3GetSessionId(&g_idTimeSyncSession);
/* The status code is ignored as this information is not available with VBox < 3.2.10. */
int rc = RTSemEventMultiCreate(&g_TimeSyncEvent);
AssertRC(rc);
#ifdef RT_OS_WINDOWS
if (RT_SUCCESS(rc))
{
/*
* Adjust privileges of this process so we can make system time adjustments.
*/
if (OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, &g_hTokenProcess))
{
TOKEN_PRIVILEGES tkPriv;
RT_ZERO(tkPriv);
tkPriv.PrivilegeCount = 1;
tkPriv.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
if (LookupPrivilegeValue(NULL, SE_SYSTEMTIME_NAME, &tkPriv.Privileges[0].Luid))
{
DWORD cbRet = sizeof(g_TkOldPrivileges);
if (AdjustTokenPrivileges(g_hTokenProcess, FALSE, &tkPriv, sizeof(TOKEN_PRIVILEGES), &g_TkOldPrivileges, &cbRet))
rc = VINF_SUCCESS;
else
{
DWORD dwErr = GetLastError();
rc = RTErrConvertFromWin32(dwErr);
VBoxServiceError("VBoxServiceTimeSyncInit: Adjusting token privileges (SE_SYSTEMTIME_NAME) failed with status code %u/%Rrc!\n", dwErr, rc);
}
}
else
{
DWORD dwErr = GetLastError();
rc = RTErrConvertFromWin32(dwErr);
VBoxServiceError("VBoxServiceTimeSyncInit: Looking up token privileges (SE_SYSTEMTIME_NAME) failed with status code %u/%Rrc!\n", dwErr, rc);
}
if (RT_FAILURE(rc))
{
CloseHandle(g_hTokenProcess);
g_hTokenProcess = NULL;
}
}
else
{
DWORD dwErr = GetLastError();
rc = RTErrConvertFromWin32(dwErr);
VBoxServiceError("VBoxServiceTimeSyncInit: Opening process token (SE_SYSTEMTIME_NAME) failed with status code %u/%Rrc!\n", dwErr, rc);
g_hTokenProcess = NULL;
}
}
if (GetSystemTimeAdjustment(&g_dwWinTimeAdjustment, &g_dwWinTimeIncrement, &g_bWinTimeAdjustmentDisabled))
VBoxServiceVerbose(3, "VBoxServiceTimeSyncInit: Initially %ld (100ns) units per %ld (100 ns) units interval, disabled=%d\n",
g_dwWinTimeAdjustment, g_dwWinTimeIncrement, g_bWinTimeAdjustmentDisabled ? 1 : 0);
else
{
DWORD dwErr = GetLastError();
rc = RTErrConvertFromWin32(dwErr);
VBoxServiceError("VBoxServiceTimeSyncInit: Could not get time adjustment values! Last error: %ld!\n", dwErr);
}
#endif /* RT_OS_WINDOWS */
return rc;
}
/**
* Try adjust the time using adjtime or similar.
*
* @returns true on success, false on failure.
*
* @param pDrift The time adjustment.
*/
static bool VBoxServiceTimeSyncAdjust(PCRTTIMESPEC pDrift)
{
#ifdef RT_OS_WINDOWS
/** @todo r=bird: NT4 doesn't have GetSystemTimeAdjustment according to MSDN. */
/** @todo r=bird: g_hTokenProcess cannot be NULL here.
* VBoxServiceTimeSyncInit will fail and the service will not be
* started with it being NULL. VBoxServiceTimeSyncInit OTOH will *NOT*
* be called until the service thread has terminated. If anything
* else is the case, there is buggy code somewhere.*/
if (g_hTokenProcess == NULL) /* Is the token already closed when shutting down? */
return false;
DWORD dwWinTimeAdjustment, dwWinNewTimeAdjustment, dwWinTimeIncrement;
BOOL fWinTimeAdjustmentDisabled;
if (GetSystemTimeAdjustment(&dwWinTimeAdjustment, &dwWinTimeIncrement, &fWinTimeAdjustmentDisabled))
{
DWORD dwDiffMax = g_dwWinTimeAdjustment * 0.50;
DWORD dwDiffNew = dwWinTimeAdjustment * 0.10;
if (RTTimeSpecGetMilli(pDrift) > 0)
{
dwWinNewTimeAdjustment = dwWinTimeAdjustment + dwDiffNew;
if (dwWinNewTimeAdjustment > (g_dwWinTimeAdjustment + dwDiffMax))
{
dwWinNewTimeAdjustment = g_dwWinTimeAdjustment + dwDiffMax;
dwDiffNew = dwDiffMax;
}
}
else
{
dwWinNewTimeAdjustment = dwWinTimeAdjustment - dwDiffNew;
if (dwWinNewTimeAdjustment < (g_dwWinTimeAdjustment - dwDiffMax))
{
dwWinNewTimeAdjustment = g_dwWinTimeAdjustment - dwDiffMax;
dwDiffNew = dwDiffMax;
}
}
VBoxServiceVerbose(3, "VBoxServiceTimeSyncAdjust: Drift=%lldms\n", RTTimeSpecGetMilli(pDrift));
VBoxServiceVerbose(3, "VBoxServiceTimeSyncAdjust: OrgTA=%ld, CurTA=%ld, NewTA=%ld, DiffNew=%ld, DiffMax=%ld\n",
g_dwWinTimeAdjustment, dwWinTimeAdjustment, dwWinNewTimeAdjustment, dwDiffNew, dwDiffMax);
if (SetSystemTimeAdjustment(dwWinNewTimeAdjustment, FALSE /* Periodic adjustments enabled. */))
{
g_cTimeSyncErrors = 0;
return true;
}
if (g_cTimeSyncErrors++ < 10)
VBoxServiceError("VBoxServiceTimeSyncAdjust: SetSystemTimeAdjustment failed, error=%u\n", GetLastError());
}
else if (g_cTimeSyncErrors++ < 10)
VBoxServiceError("VBoxServiceTimeSyncAdjust: GetSystemTimeAdjustment failed, error=%ld\n", GetLastError());
#elif defined(RT_OS_OS2) || defined(RT_OS_HAIKU)
/* No API for doing gradual time adjustments. */
#else /* PORTME */
/*
* Try use adjtime(), most unix-like systems have this.
*/
struct timeval tv;
RTTimeSpecGetTimeval(pDrift, &tv);
if (adjtime(&tv, NULL) == 0)
{
if (g_cVerbosity >= 1)
VBoxServiceVerbose(1, "VBoxServiceTimeSyncAdjust: adjtime by %RDtimespec\n", pDrift);
g_cTimeSyncErrors = 0;
return true;
}
#endif
/* failed */
return false;
}
/**
* Cancels any pending time adjustment.
*
* Called when we've caught up and before calls to VBoxServiceTimeSyncSet.
*/
static void VBoxServiceTimeSyncCancelAdjust(void)
{
#ifdef RT_OS_WINDOWS
/** @todo r=bird: g_hTokenProcess cannot be NULL here. See argumentation in
* VBoxServiceTimeSyncAdjust. */
if (g_hTokenProcess == NULL) /* No process token (anymore)? */
return;
if (SetSystemTimeAdjustment(0, TRUE /* Periodic adjustments disabled. */))
VBoxServiceVerbose(3, "VBoxServiceTimeSyncCancelAdjust: Windows Time Adjustment is now disabled.\n");
else if (g_cTimeSyncErrors++ < 10)
VBoxServiceError("VBoxServiceTimeSyncCancelAdjust: SetSystemTimeAdjustment(,disable) failed, error=%u\n", GetLastError());
#endif /* !RT_OS_WINDOWS */
}
/**
* Try adjust the time using adjtime or similar.
*
* @returns true on success, false on failure.
*
* @param pDrift The time adjustment.
*/
static void VBoxServiceTimeSyncSet(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;
VBoxServiceVerbose(1, "time set to %s\n",
RTTimeToString(RTTimeExplode(&Time, &NewGuestTime), sz, sizeof(sz)));
#ifdef DEBUG
RTTIMESPEC Tmp;
if (g_cVerbosity >= 3)
VBoxServiceVerbose(3, " now %s\n",
RTTimeToString(RTTimeExplode(&Time, RTTimeNow(&Tmp)), sz, sizeof(sz)));
#endif
}
}
else if (g_cTimeSyncErrors++ < 10)
VBoxServiceError("VBoxServiceTimeSyncSet: RTTimeSet(%RDtimespec) failed: %Rrc\n", &NewGuestTime, rc);
}
/** @copydoc VBOXSERVICE::pfnWorker */
DECLCALLBACK(int) VBoxServiceTimeSyncWorker(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)
VBoxServiceError("VBoxServiceTimeSyncWorker: 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)
{
VBoxServiceVerbose(3, "VBoxServiceTimeSyncWorker: 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)
{
VBoxServiceVerbose(3, "VBoxServiceTimeSyncWorker: Host: %s (MinAdjust: %RU32 ms)\n",
RTTimeToString(RTTimeExplode(&Time, &HostNow), sz, sizeof(sz)), MinAdjust);
VBoxServiceVerbose(3, "VBoxServiceTimeSyncWorker: 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
|| !VBoxServiceTimeSyncAdjust(&Drift))
{
VBoxServiceTimeSyncCancelAdjust();
VBoxServiceTimeSyncSet(&Drift);
}
}
else
VBoxServiceTimeSyncCancelAdjust();
break;
}
VBoxServiceVerbose(3, "VBoxServiceTimeSyncWorker: %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))
{
VBoxServiceError("VBoxServiceTimeSyncWorker: RTSemEventMultiWait failed; rc2=%Rrc\n", rc2);
rc = rc2;
break;
}
}
VBoxServiceTimeSyncCancelAdjust();
RTSemEventMultiDestroy(g_TimeSyncEvent);
g_TimeSyncEvent = NIL_RTSEMEVENTMULTI;
return rc;
}
/** @copydoc VBOXSERVICE::pfnStop */
static DECLCALLBACK(void) VBoxServiceTimeSyncStop(void)
{
RTSemEventMultiSignal(g_TimeSyncEvent);
}
/** @copydoc VBOXSERVICE::pfnTerm */
static DECLCALLBACK(void) VBoxServiceTimeSyncTerm(void)
{
#ifdef RT_OS_WINDOWS
/*
* Restore the SE_SYSTEMTIME_NAME token privileges (if init succeeded).
*/
if (g_hTokenProcess)
{
if (!AdjustTokenPrivileges(g_hTokenProcess, FALSE, &g_TkOldPrivileges, sizeof(TOKEN_PRIVILEGES), NULL, NULL))
{
DWORD dwErr = GetLastError();
VBoxServiceError("VBoxServiceTimeSyncTerm: Restoring token privileges (SE_SYSTEMTIME_NAME) failed with code %u!\n", dwErr);
}
CloseHandle(g_hTokenProcess);
g_hTokenProcess = NULL;
}
#endif /* !RT_OS_WINDOWS */
if (g_TimeSyncEvent != NIL_RTSEMEVENTMULTI)
{
RTSemEventMultiDestroy(g_TimeSyncEvent);
g_TimeSyncEvent = NIL_RTSEMEVENTMULTI;
}
}
/**
* The 'timesync' service description.
*/
VBOXSERVICE g_TimeSync =
{
/* pszName. */
"timesync",
/* pszDescription. */
"Time synchronization",
/* pszUsage. */
" [--timesync-interval <ms>] [--timesync-min-adjust <ms>]\n"
" [--timesync-latency-factor <x>] [--timesync-max-latency <ms>]\n"
" [--timesync-set-threshold <ms>] [--timesync-set-start]\n"
" [--timesync-set-on-restore 0|1]"
,
/* pszOptions. */
" --timesync-interval Specifies the interval at which to synchronize the\n"
" time with the host. The default is 10000 ms.\n"
" --timesync-min-adjust The minimum absolute drift value measured in\n"
" milliseconds to make adjustments for.\n"
" The default is 1000 ms on OS/2 and 100 ms elsewhere.\n"
" --timesync-latency-factor\n"
" The factor to multiply the time query latency with\n"
" to calculate the dynamic minimum adjust time.\n"
" The default is 8 times.\n"
" --timesync-max-latency The max host timer query latency to accept.\n"
" The default is 250 ms.\n"
" --timesync-set-threshold\n"
" The absolute drift threshold, given as milliseconds,\n"
" where to start setting the time instead of trying to\n"
" adjust it. The default is 20 min.\n"
" --timesync-set-start Set the time when starting the time sync service.\n"
" --timesync-set-on-restore 0|1\n"
" Immediately set the time when the VM was restored.\n"
" 1 = set (default), 0 = don't set.\n"
,
/* methods */
VBoxServiceTimeSyncPreInit,
VBoxServiceTimeSyncOption,
VBoxServiceTimeSyncInit,
VBoxServiceTimeSyncWorker,
VBoxServiceTimeSyncStop,
VBoxServiceTimeSyncTerm
};