#include <ntoskrnl.h>
#include <debug.h>

Include dependency graph for time.c:

Macros
#define	NDEBUG

#define	TICKSPERMINUTE 600000000

Functions
static BOOLEAN	ExpGetTimeZoneId (_In_ PLARGE_INTEGER TimeNow, _Out_ PULONG TimeZoneId, _Out_ PLARGE_INTEGER NewTimeZoneBias)

BOOLEAN NTAPI	ExAcquireTimeRefreshLock (IN BOOLEAN Wait)

VOID NTAPI	ExReleaseTimeRefreshLock (VOID)

ULONG NTAPI	ExSetTimerResolution (IN ULONG DesiredTime, IN BOOLEAN SetResolution)

VOID NTAPI	ExUpdateSystemTimeFromCmos (IN BOOLEAN UpdateInterruptTime, IN ULONG MaxSepInSeconds)

BOOLEAN NTAPI	ExRefreshTimeZoneInformation (IN PLARGE_INTEGER CurrentBootTime)

NTSTATUS	ExpSetTimeZoneInformation (PRTL_TIME_ZONE_INFORMATION TimeZoneInformation)

NTSTATUS NTAPI	NtSetSystemTime (IN PLARGE_INTEGER SystemTime, OUT PLARGE_INTEGER PreviousTime OPTIONAL)

NTSTATUS NTAPI	NtQuerySystemTime (OUT PLARGE_INTEGER SystemTime)

VOID NTAPI	ExLocalTimeToSystemTime (PLARGE_INTEGER LocalTime, PLARGE_INTEGER SystemTime)

VOID NTAPI	ExSystemTimeToLocalTime (PLARGE_INTEGER SystemTime, PLARGE_INTEGER LocalTime)

NTSTATUS NTAPI	NtQueryTimerResolution (OUT PULONG MinimumResolution, OUT PULONG MaximumResolution, OUT PULONG ActualResolution)

NTSTATUS NTAPI	NtSetTimerResolution (IN ULONG DesiredResolution, IN BOOLEAN SetResolution, OUT PULONG CurrentResolution)

Variables
RTL_TIME_ZONE_INFORMATION	ExpTimeZoneInfo

ULONG	ExpLastTimeZoneBias = -1

LARGE_INTEGER	ExpTimeZoneBias

ULONG	ExpAltTimeZoneBias

ULONG	ExpTimeZoneId

ULONG	ExpTickCountMultiplier

ERESOURCE	ExpTimeRefreshLock

ULONG	ExpKernelResolutionCount = 0

ULONG	ExpTimerResolutionCount = 0

Macro Definition Documentation

◆ NDEBUG

#define NDEBUG

Definition at line 13 of file time.c.

◆ TICKSPERMINUTE

#define TICKSPERMINUTE 600000000

Definition at line 16 of file time.c.

Function Documentation

◆ ExAcquireTimeRefreshLock()

BOOLEAN NTAPI ExAcquireTimeRefreshLock ( IN BOOLEAN Wait )

Definition at line 145 of file time.c.

{
    /* Block APCs */
    KeEnterCriticalRegion();
 
    /* Attempt lock acquisition */
    if (!(ExAcquireResourceExclusiveLite(&ExpTimeRefreshLock, Wait)))
    {
        /* Lock was not acquired, enable APCs and fail */
        KeLeaveCriticalRegion();
        return FALSE;
    }
 
    /* Lock has been acquired */
    return TRUE;
}

Referenced by ExSetTimerResolution(), and KdpTimeSlipWork().

◆ ExLocalTimeToSystemTime()

VOID NTAPI ExLocalTimeToSystemTime	(	PLARGE_INTEGER	LocalTime,
		PLARGE_INTEGER	SystemTime
	)

Definition at line 605 of file time.c.

{
    SystemTime->QuadPart = LocalTime->QuadPart + ExpTimeZoneBias.QuadPart;
}

◆ ExpGetTimeZoneId()

static BOOLEAN ExpGetTimeZoneId	(	_In_ PLARGE_INTEGER	TimeNow,
		_Out_ PULONG	TimeZoneId,
		_Out_ PLARGE_INTEGER	NewTimeZoneBias
	)

static

Definition at line 39 of file time.c.

{
    LARGE_INTEGER StandardTime;
    LARGE_INTEGER DaylightTime;
    LARGE_INTEGER LocalTimeNow = *TimeNow;
    NTSTATUS Status;
 
    DPRINT("ExpGetTimeZoneId\n");
 
    /* Read time zone information from the registry */
    Status = RtlQueryTimeZoneInformation(&ExpTimeZoneInfo);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("RtlQueryTimeZoneInformation failed (Status 0x%08lx)\n", Status);
        return FALSE;
    }
 
    /* Get the default bias */
    NewTimeZoneBias->QuadPart = (LONGLONG)ExpTimeZoneInfo.Bias * TICKSPERMINUTE;
 
    if (ExpTimeZoneInfo.StandardDate.Month != 0 &&
        ExpTimeZoneInfo.DaylightDate.Month != 0)
    {
        /* Get this year's standard start time */
        if (!RtlCutoverTimeToSystemTime(&ExpTimeZoneInfo.StandardDate,
                                        &StandardTime,
                                        &LocalTimeNow,
                                        TRUE))
        {
            DPRINT1("RtlCutoverTimeToSystemTime for StandardDate failed\n");
            return FALSE;
        }
 
        /* Get this year's daylight start time */
        if (!RtlCutoverTimeToSystemTime(&ExpTimeZoneInfo.DaylightDate,
                                        &DaylightTime,
                                        &LocalTimeNow,
                                        TRUE))
        {
            DPRINT1("RtlCutoverTimeToSystemTime for DaylightDate failed\n");
            return FALSE;
        }
 
        /* Determine the time zone id and update the time zone bias */
        if (DaylightTime.QuadPart < StandardTime.QuadPart)
        {
            if ((LocalTimeNow.QuadPart >= DaylightTime.QuadPart) &&
                (LocalTimeNow.QuadPart < StandardTime.QuadPart))
            {
                DPRINT("Daylight time\n");
                *TimeZoneId = TIME_ZONE_ID_DAYLIGHT;
                NewTimeZoneBias->QuadPart += (LONGLONG)ExpTimeZoneInfo.DaylightBias * TICKSPERMINUTE;
            }
            else
            {
                DPRINT("Standard time\n");
                *TimeZoneId = TIME_ZONE_ID_STANDARD;
                NewTimeZoneBias->QuadPart += (LONGLONG)ExpTimeZoneInfo.StandardBias * TICKSPERMINUTE;
            }
        }
        else
        {
            if ((LocalTimeNow.QuadPart >= StandardTime.QuadPart) &&
                (LocalTimeNow.QuadPart < DaylightTime.QuadPart))
            {
                DPRINT("Standard time\n");
                *TimeZoneId = TIME_ZONE_ID_STANDARD;
                NewTimeZoneBias->QuadPart += (LONGLONG)ExpTimeZoneInfo.StandardBias * TICKSPERMINUTE;
            }
            else
            {
                DPRINT("Daylight time\n");
                *TimeZoneId = TIME_ZONE_ID_DAYLIGHT;
                NewTimeZoneBias->QuadPart += (LONGLONG)ExpTimeZoneInfo.DaylightBias * TICKSPERMINUTE;
            }
        }
    }
    else
    {
        *TimeZoneId = TIME_ZONE_ID_UNKNOWN;
    }
 
    return TRUE;
}

Referenced by ExpSetTimeZoneInformation(), and ExRefreshTimeZoneInformation().

◆ ExpSetTimeZoneInformation()

NTSTATUS ExpSetTimeZoneInformation ( PRTL_TIME_ZONE_INFORMATION TimeZoneInformation )

Definition at line 357 of file time.c.

{
    LARGE_INTEGER LocalTime, SystemTime, OldTime, NewTimeZoneBias;
    TIME_FIELDS TimeFields;
    BOOLEAN Success;
    NTSTATUS Status;
    LARGE_INTEGER LocalTimeNow;
 
    DPRINT("ExpSetTimeZoneInformation called\n");
 
    /* Read time zone information from the registry */
    Status = RtlQueryTimeZoneInformation(&ExpTimeZoneInfo);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("RtlQueryTimeZoneInformation failed (Status 0x%08lx)\n", Status);
        return FALSE;
    }
 
    /* Get the default bias */
    NewTimeZoneBias.QuadPart = (LONGLONG)ExpTimeZoneInfo.Bias * TICKSPERMINUTE;
 
    /* Get the Shared User Data System Time into the local SystemTime */
    KeQuerySystemTime(&SystemTime);
 
    LocalTimeNow = SystemTime;
 
    /* Adjust LocalTimeNow for Time Zone Bias to use UTC for comparisons */
    LocalTimeNow.QuadPart -= NewTimeZoneBias.QuadPart;
 
    /* Set the Global Data for ExpTimeZoneBias and ExpTimeZoneId */
    Success = ExpGetTimeZoneId(&LocalTimeNow, &ExpTimeZoneId, &NewTimeZoneBias);
    if (!Success)
    {
        DPRINT1("ExpGetTimeZoneId failed\n");
        return STATUS_UNSUCCESSFUL;
    }
    DPRINT("ExpTimeZoneId is %lu\n", ExpTimeZoneId);
 
    ExpTimeZoneBias = NewTimeZoneBias;
 
    DPRINT("Old time zone bias: %d minutes\n", ExpTimeZoneInfo.Bias);
    DPRINT("Old time zone standard bias: %d minutes\n",
            ExpTimeZoneInfo.StandardBias);
    DPRINT("New time zone bias: %d minutes\n", TimeZoneInformation->Bias);
    DPRINT("New time zone standard bias: %d minutes\n",
            TimeZoneInformation->StandardBias);
 
    /* Get the local time */
    HalQueryRealTimeClock(&TimeFields);
    RtlTimeFieldsToTime(&TimeFields, &LocalTime);
 
    /* Calculate the bias */
    ExpTimeZoneBias.QuadPart = ((LONGLONG)(TimeZoneInformation->Bias +
                                           TimeZoneInformation->StandardBias)) *
                                           TICKSPERMINUTE;
 
    /* If Daylight Savings Time then add the DayLightBias to the Time Zone Bias */
    if (ExpTimeZoneId == TIME_ZONE_ID_DAYLIGHT)
        ExpTimeZoneBias.QuadPart += (LONGLONG)ExpTimeZoneInfo.DaylightBias * TICKSPERMINUTE;
 
    /* Copy the timezone information */
    RtlCopyMemory(&ExpTimeZoneInfo,
                  TimeZoneInformation,
                  sizeof(RTL_TIME_ZONE_INFORMATION));
 
    /* Set the new time zone information */
    KiWriteSystemTime(&SharedUserData->TimeZoneBias, ExpTimeZoneBias);
    SharedUserData->TimeZoneId = ExpTimeZoneId;
 
    DPRINT("New time zone bias: %I64d minutes\n",
            ExpTimeZoneBias.QuadPart / TICKSPERMINUTE);
 
    /* Calculate the new system time */
    ExLocalTimeToSystemTime(&LocalTime, &SystemTime);
 
    /* Set the new system time and notify the system */
    KeSetSystemTime(&SystemTime, &OldTime, FALSE, NULL);
    PoNotifySystemTimeSet();
 
    /* Return success */
    DPRINT("ExpSetTimeZoneInformation done\n");
    return STATUS_SUCCESS;
}

Referenced by NtSetSystemTime(), and SSI_DEF().

◆ ExRefreshTimeZoneInformation()

BOOLEAN NTAPI ExRefreshTimeZoneInformation ( IN PLARGE_INTEGER CurrentBootTime )

Definition at line 320 of file time.c.

{
    LARGE_INTEGER CurrentTime, NewTimeZoneBias;
    BOOLEAN Success;
 
    DPRINT("ExRefreshTimeZoneInformation\n");
 
    /* Set the global data for ExpTimeZoneBias and the Time Zone ID */
    Success = ExpGetTimeZoneId(CurrentBootTime, &ExpTimeZoneId, &NewTimeZoneBias);
    if (!Success)
    {
        DPRINT1("ExpGetTimeZoneId failed\n");
        return FALSE;
    }
    DPRINT("ExpTimeZoneId is %lu\n", ExpTimeZoneId);
 
    ExpTimeZoneBias = NewTimeZoneBias;
 
    /* Change SharedUserData->TimeZoneBias for user-mode applications */
    KiWriteSystemTime(&SharedUserData->TimeZoneBias, ExpTimeZoneBias);
    SharedUserData->TimeZoneId = ExpTimeZoneId;
 
    /* Convert boot time from local time to UTC */
    KeBootTime.QuadPart += ExpTimeZoneBias.QuadPart;
 
    /* Convert system time from local time to UTC */
    KeQuerySystemTime(&CurrentTime);;
 
    /* Change it for user-mode applications */
    CurrentTime.QuadPart += ExpTimeZoneBias.QuadPart;
    KiWriteSystemTime(&SharedUserData->SystemTime, CurrentTime);
 
    /* Return success */
    return TRUE;
}

Referenced by Phase1InitializationDiscard().

◆ ExReleaseTimeRefreshLock()

VOID NTAPI ExReleaseTimeRefreshLock ( VOID )

Definition at line 177 of file time.c.

{
    /* Release the lock and re-enable APCs */
    ExReleaseResourceLite(&ExpTimeRefreshLock);
    KeLeaveCriticalRegion();
}

Referenced by ExSetTimerResolution(), and KdpTimeSlipWork().

◆ ExSetTimerResolution()

ULONG NTAPI ExSetTimerResolution	(	IN ULONG	DesiredTime,
		IN BOOLEAN	SetResolution
	)

Definition at line 225 of file time.c.

{
    ULONG CurrentIncrement;
 
    /* Wait for clock interrupt frequency and power requests to synchronize */
    ExAcquireTimeRefreshLock(TRUE);
 
    /* Obey remark 2*/
    CurrentIncrement = KeTimeIncrement;
 
    /* Check the type of operation this is */
    if (SetResolution)
    {
        /*
         * If this is the first kernel change, bump the timer resolution change
         * count, then bump the kernel change count as well.
         *
         * These two variables are tracked differently since user-mode processes
         * can also change the timer resolution through the NtSetTimerResolution
         * system call. A per-process flag in the EPROCESS then stores the per-
         * process change state.
         *
         */
        if (!ExpKernelResolutionCount++) ExpTimerResolutionCount++;
 
        /* Obey remark 3 */
        if (DesiredTime < KeMinimumIncrement) DesiredTime = KeMinimumIncrement;
 
        /* Obey remark 1 */
        if (DesiredTime < KeTimeIncrement)
        {
            /* Force this thread on CPU zero, since we don't want it to drift */
            KeSetSystemAffinityThread(1);
 
            /* Now call the platform driver (HAL) to make the change */
            CurrentIncrement = HalSetTimeIncrement(DesiredTime);
 
            /* Put the thread back to its original affinity */
            KeRevertToUserAffinityThread();
 
            /* Finally, keep track of the new value in the kernel */
            KeTimeIncrement = CurrentIncrement;
        }
    }
    else
    {
        /* First, make sure that a driver has actually changed the resolution */
        if (ExpKernelResolutionCount)
        {
            /* Obey remark 4 */
            if (--ExpKernelResolutionCount)
            {
                /*
                 * All kernel drivers have requested the original frequency to
                 * be restored, but there might still be user processes with an
                 * ongoing clock interrupt frequency change, so make sure that
                 * this isn't the case.
                 */
                if (--ExpTimerResolutionCount)
                {
                    /* Force this thread on one CPU so that it doesn't drift */
                    KeSetSystemAffinityThread(1);
 
                    /* Call the HAL to restore the frequency to its default */
                    CurrentIncrement = HalSetTimeIncrement(KeMaximumIncrement);
 
                    /* Put the thread back to its original affinity */
                    KeRevertToUserAffinityThread();
 
                    /* Finally, keep track of the new value in the kernel */
                    KeTimeIncrement = CurrentIncrement;
                }
            }
        }
    }
 
    /* Release the clock interrupt frequency lock since changes are done */
    ExReleaseTimeRefreshLock();
 
    /* And return the current value -- which could reflect the new frequency */
    return CurrentIncrement;
}

Referenced by NtSetTimerResolution().

◆ ExSystemTimeToLocalTime()

VOID NTAPI ExSystemTimeToLocalTime	(	PLARGE_INTEGER	SystemTime,
		PLARGE_INTEGER	LocalTime
	)

Definition at line 616 of file time.c.

{
    LocalTime->QuadPart = SystemTime->QuadPart - ExpTimeZoneBias.QuadPart;
}

◆ ExUpdateSystemTimeFromCmos()

VOID NTAPI ExUpdateSystemTimeFromCmos	(	IN BOOLEAN	UpdateInterruptTime,
		IN ULONG	MaxSepInSeconds
	)

Definition at line 311 of file time.c.

{
    /* FIXME: TODO */
    return;
}

Referenced by KdpTimeSlipWork().

◆ NtQuerySystemTime()

NTSTATUS NTAPI NtQuerySystemTime ( OUT PLARGE_INTEGER SystemTime )

Definition at line 563 of file time.c.

{
    KPROCESSOR_MODE PreviousMode = ExGetPreviousMode();
    PAGED_CODE();
 
    /* Check if we were called from user-mode */
    if (PreviousMode != KernelMode)
    {
        _SEH2_TRY
        {
            /* Verify the time pointer */
            ProbeForWriteLargeInteger(SystemTime);
 
            /*
             * It's safe to pass the pointer directly to KeQuerySystemTime
             * as it's just a basic copy to this pointer. If it raises an
             * exception nothing dangerous can happen!
             */
            KeQuerySystemTime(SystemTime);
        }
        _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
        {
            /* Return the exception code */
            _SEH2_YIELD(return _SEH2_GetExceptionCode());
        }
        _SEH2_END;
    }
    else
    {
        /* Query the time directly */
        KeQuerySystemTime(SystemTime);
    }
 
    /* Return success */
    return STATUS_SUCCESS;
}

Referenced by CalcVolumeSerialNumber(), clock(), create_bad_block_inode(), CreateSignature(), ElfReportEventA(), ElfReportEventW(), ext2_flush(), ext2_initialize_sb(), ext2_mkdir(), GetDynamicTimeZoneInformation(), GetLocalTime(), GetPasswordAge(), GetSystemTime(), GetSystemTimeAsFileTime(), HTTP_ProcessExpires(), LogfReportEvent(), LogfWriteRecord(), LsapCreateDatabaseObjects(), LsapCreateRandomDomainSid(), LsarCreateSecret(), LsarSetSecret(), LsarStorePrivateData(), msvcrt_init_clock(), NetrRemoteTOD(), NtProcessStartup(), RtlRunEncodeUnicodeString(), SampSetupCreateDomain(), SampSetUserAll(), SampSetUserInternal1(), SampSetUserInternal2(), SamrChangePasswordUser(), SamValidateNormalUser(), SetDiskSignature(), SetLogonTimestamp(), START_TEST(), test_GetSystemTimeAsFileTime(), test_perf_counters(), test_performance_keys(), Test_ProcessTimes(), test_tp_timer(), test_tp_wait(), test_tp_window_length(), test_user_shared_data_time(), timerqueue_thread_proc(), TpSetTimer(), TpSetWait(), and waitqueue_thread_proc().

◆ NtQueryTimerResolution()

NTSTATUS NTAPI NtQueryTimerResolution	(	OUT PULONG	MinimumResolution,
		OUT PULONG	MaximumResolution,
		OUT PULONG	ActualResolution
	)

Definition at line 627 of file time.c.

{
    KPROCESSOR_MODE PreviousMode = ExGetPreviousMode();
 
    /* Check if the call came from user-mode */
    if (PreviousMode != KernelMode)
    {
        _SEH2_TRY
        {
            /* Probe the parameters */
            ProbeForWriteUlong(MinimumResolution);
            ProbeForWriteUlong(MaximumResolution);
            ProbeForWriteUlong(ActualResolution);
 
            /*
             * Set the parameters to the actual values.
             *
             * NOTE:
             * MinimumResolution corresponds to the biggest time increment and
             * MaximumResolution corresponds to the smallest time increment.
             */
            *MinimumResolution = KeMaximumIncrement;
            *MaximumResolution = KeMinimumIncrement;
            *ActualResolution  = KeTimeIncrement;
        }
        _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
        {
            /* Return the exception code */
            _SEH2_YIELD(return _SEH2_GetExceptionCode());
        }
        _SEH2_END;
    }
    else
    {
        /* Set the parameters to the actual values */
        *MinimumResolution = KeMaximumIncrement;
        *MaximumResolution = KeMinimumIncrement;
        *ActualResolution  = KeTimeIncrement;
    }
 
    /* Return success */
    return STATUS_SUCCESS;
}

Referenced by START_TEST(), and test_TimerResolution().

◆ NtSetSystemTime()

NTSTATUS NTAPI NtSetSystemTime	(	IN PLARGE_INTEGER	SystemTime,
		OUT PLARGE_INTEGER PreviousTime	OPTIONAL
	)

Definition at line 452 of file time.c.

{
    LARGE_INTEGER OldSystemTime;
    LARGE_INTEGER NewSystemTime;
    LARGE_INTEGER LocalTime;
    TIME_FIELDS TimeFields;
    KPROCESSOR_MODE PreviousMode = ExGetPreviousMode();
    NTSTATUS Status = STATUS_SUCCESS;
    RTL_TIME_ZONE_INFORMATION TimeZoneInformation = { 0 };
    ULONG TimeZoneIdSave;
 
    PAGED_CODE();
 
    // TODO: Handle the case when SystemTime == NULL, which means:
    // "update system time using the current time-zone information".
    if (!SystemTime)
    {
        UNIMPLEMENTED;
        return STATUS_NOT_IMPLEMENTED;
    }
 
    /* Check if we were called from user-mode */
    if (PreviousMode != KernelMode)
    {
        _SEH2_TRY
        {
            /* Verify the time pointers */
            NewSystemTime = ProbeForReadLargeInteger(SystemTime);
            if (PreviousTime) ProbeForWriteLargeInteger(PreviousTime);
        }
        _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
        {
            /* Return the exception code */
            _SEH2_YIELD(return _SEH2_GetExceptionCode());
        }
        _SEH2_END;
    }
    else
    {
        /* Reuse the pointer */
        NewSystemTime = *SystemTime;
    }
 
    /* Make sure we have permission to change the time */
    if (!SeSinglePrivilegeCheck(SeSystemtimePrivilege, PreviousMode))
    {
        DPRINT1("NtSetSystemTime: Caller requires the "
                "SeSystemtimePrivilege privilege!\n");
        return STATUS_PRIVILEGE_NOT_HELD;
    }
 
    /* Convert the time and set it in HAL */
    ExSystemTimeToLocalTime(&NewSystemTime, &LocalTime);
    RtlTimeToTimeFields(&LocalTime, &TimeFields);
    HalSetRealTimeClock(&TimeFields);
 
    /* Now set the system time and notify the system */
    KeSetSystemTime(&NewSystemTime, &OldSystemTime, FALSE, NULL);
    PoNotifySystemTimeSet();
 
    /* Check if caller wanted previous time */
    if (PreviousTime)
    {
        /* Enter SEH Block for return */
        _SEH2_TRY
        {
            /* Return the previous time */
            *PreviousTime = OldSystemTime;
        }
        _SEH2_EXCEPT(ExSystemExceptionFilter())
        {
            /* Get the exception code */
            Status = _SEH2_GetExceptionCode();
        }
        _SEH2_END;
    }
 
    /* Read time zone information from the registry and set the clock */
    Status = RtlQueryTimeZoneInformation(&TimeZoneInformation);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("RtlQueryTimeZoneInformation failed (Status 0x%08lx)\n", Status);
    }
 
    /* Test if we went from Daylight to Standard Time or vice versa */
    TimeZoneIdSave = ExpTimeZoneId;
    ExpSetTimeZoneInformation(&TimeZoneInformation);
 
    if (ExpTimeZoneId != TimeZoneIdSave)
    {
        /* Going from DT to ST or vice versa we need to repeat this */
        DPRINT("Daylight Time and Standard Time are switching\n");
 
        /* Set the system time and notify the system */
        KeSetSystemTime(&NewSystemTime, &OldSystemTime, FALSE, NULL);
        PoNotifySystemTimeSet();
    }
 
    /* Return status */
    return Status;
}

Referenced by SetLocalTime(), and SetSystemTime().

◆ NtSetTimerResolution()

NTSTATUS NTAPI NtSetTimerResolution	(	IN ULONG	DesiredResolution,
		IN BOOLEAN	SetResolution,
		OUT PULONG	CurrentResolution
	)

Definition at line 678 of file time.c.

{
    NTSTATUS Status;
    KPROCESSOR_MODE PreviousMode = ExGetPreviousMode();
    PEPROCESS Process = PsGetCurrentProcess();
    ULONG NewResolution;
 
    /* Check if the call came from user-mode */
    if (PreviousMode != KernelMode)
    {
        _SEH2_TRY
        {
            /* Probe the parameter */
            ProbeForWriteUlong(CurrentResolution);
        }
        _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
        {
            /* Return the exception code */
            _SEH2_YIELD(return _SEH2_GetExceptionCode());
        }
        _SEH2_END;
    }
 
    /* Set and return the new resolution */
    NewResolution = ExSetTimerResolution(DesiredResolution, SetResolution);
 
    if (PreviousMode != KernelMode)
    {
        _SEH2_TRY
        {
            *CurrentResolution = NewResolution;
        }
        _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
        {
            /* Return the exception code */
            _SEH2_YIELD(return _SEH2_GetExceptionCode());
        }
        _SEH2_END;
    }
    else
    {
        *CurrentResolution = NewResolution;
    }
 
    if (SetResolution || Process->SetTimerResolution)
    {
        /* The resolution has been changed now or in an earlier call */
        Status = STATUS_SUCCESS;
    }
    else
    {
        /* The resolution hasn't been changed */
        Status = STATUS_TIMER_RESOLUTION_NOT_SET;
    }
 
    /* Update the flag */
    Process->SetTimerResolution = SetResolution;
 
    return Status;
}