critical.c File Reference

#include <rtl.h>
#include <debug.h>

Include dependency graph for critical.c:

Go to the source code of this file.

Macros
#define	NDEBUG
#define	MAX_STATIC_CS_DEBUG_OBJECTS   64

Functions
	_At_ (CriticalSection->LockSemaphore, _Post_notnull_) VOID NTAPI RtlpCreateCriticalSectionSem(PRTL_CRITICAL_SECTION CriticalSection)
NTSTATUS NTAPI	RtlpWaitForCriticalSection (PRTL_CRITICAL_SECTION CriticalSection)
VOID NTAPI	RtlpUnWaitCriticalSection (PRTL_CRITICAL_SECTION CriticalSection)
VOID NTAPI	RtlpInitDeferedCriticalSection (VOID)
PRTL_CRITICAL_SECTION_DEBUG NTAPI	RtlpAllocateDebugInfo (VOID)
VOID NTAPI	RtlpFreeDebugInfo (PRTL_CRITICAL_SECTION_DEBUG DebugInfo)
NTSTATUS NTAPI	RtlDeleteCriticalSection (PRTL_CRITICAL_SECTION CriticalSection)
ULONG NTAPI	RtlSetCriticalSectionSpinCount (PRTL_CRITICAL_SECTION CriticalSection, ULONG SpinCount)
NTSTATUS NTAPI	RtlEnterCriticalSection (PRTL_CRITICAL_SECTION CriticalSection)
NTSTATUS NTAPI	RtlInitializeCriticalSection (PRTL_CRITICAL_SECTION CriticalSection)
NTSTATUS NTAPI	RtlInitializeCriticalSectionAndSpinCount (PRTL_CRITICAL_SECTION CriticalSection, ULONG SpinCount)
LONG NTAPI	RtlGetCriticalSectionRecursionCount (PRTL_CRITICAL_SECTION CriticalSection)
NTSTATUS NTAPI	RtlLeaveCriticalSection (PRTL_CRITICAL_SECTION CriticalSection)
BOOLEAN NTAPI	RtlTryEnterCriticalSection (PRTL_CRITICAL_SECTION CriticalSection)
VOID NTAPI	RtlCheckForOrphanedCriticalSections (HANDLE ThreadHandle)
ULONG NTAPI	RtlIsCriticalSectionLocked (PRTL_CRITICAL_SECTION CriticalSection)
ULONG NTAPI	RtlIsCriticalSectionLockedByThread (PRTL_CRITICAL_SECTION CriticalSection)

Variables
static RTL_CRITICAL_SECTION	RtlCriticalSectionLock
static LIST_ENTRY	RtlCriticalSectionList
static BOOLEAN	RtlpCritSectInitialized = FALSE
static RTL_CRITICAL_SECTION_DEBUG	RtlpStaticDebugInfo [MAX_STATIC_CS_DEBUG_OBJECTS]
static BOOLEAN	RtlpDebugInfoFreeList [MAX_STATIC_CS_DEBUG_OBJECTS]
LARGE_INTEGER	RtlpTimeout
BOOLEAN	LdrpShutdownInProgress
HANDLE	LdrpShutdownThreadId

Macro Definition Documentation

MAX_STATIC_CS_DEBUG_OBJECTS

#define MAX_STATIC_CS_DEBUG_OBJECTS   64

Definition at line 17 of file critical.c.

NDEBUG

#define NDEBUG

Definition at line 14 of file critical.c.

Function Documentation

_At_()

_At_	(	CriticalSection->	LockSemaphore,
		_Post_notnull_
	)

Definition at line 46 of file critical.c.

{
    HANDLE hEvent = CriticalSection->LockSemaphore;
    HANDLE hNewEvent;
    NTSTATUS Status;

    /* Check if we have an event */
    if (!hEvent)
    {
        /* No, so create it */
        Status = NtCreateEvent(&hNewEvent,
                               EVENT_ALL_ACCESS,
                               NULL,
                               SynchronizationEvent,
                               FALSE);
        if (!NT_SUCCESS(Status))
        {
            DPRINT1("Failed to Create Event!\n");

            /*
             * Use INVALID_HANDLE_VALUE (-1) to signal that
             * the global keyed event must be used.
             */
            hNewEvent = INVALID_HANDLE_VALUE;
        }

        DPRINT("Created Event: %p \n", hNewEvent);

        /* Exchange the LockSemaphore field with the new handle, if it is still 0 */
        if (InterlockedCompareExchangePointer((PVOID*)&CriticalSection->LockSemaphore,
                                              (PVOID)hNewEvent,
                                               NULL) != NULL)
        {
            /* Someone else just created an event */
            if (hNewEvent != INVALID_HANDLE_VALUE)
            {
                DPRINT("Closing already created event: %p\n", hNewEvent);
                NtClose(hNewEvent);
            }
        }
    }

    return;
}

RtlCheckForOrphanedCriticalSections()

VOID NTAPI RtlCheckForOrphanedCriticalSections

(

HANDLE

ThreadHandle

)

Definition at line 784 of file critical.c.

{
    UNIMPLEMENTED;
}

RtlDeleteCriticalSection()

NTSTATUS NTAPI RtlDeleteCriticalSection

(

PRTL_CRITICAL_SECTION

CriticalSection

)

Definition at line 395 of file critical.c.

{
    NTSTATUS Status = STATUS_SUCCESS;

    DPRINT("Deleting Critical Section: %p\n", CriticalSection);

    /* Close the Event Object Handle if it exists */
    if (CriticalSection->LockSemaphore)
    {
        /* In case NtClose fails, return the status */
        Status = NtClose(CriticalSection->LockSemaphore);
    }

    /* Protect List */
    RtlEnterCriticalSection(&RtlCriticalSectionLock);

    if (CriticalSection->DebugInfo)
    {
        /* Remove it from the list */
        RemoveEntryList(&CriticalSection->DebugInfo->ProcessLocksList);
#if 0
        /* We need to preserve Flags for RtlpFreeDebugInfo */
        RtlZeroMemory(CriticalSection->DebugInfo, sizeof(RTL_CRITICAL_SECTION_DEBUG));
#endif
    }

    /* Unprotect */
    RtlLeaveCriticalSection(&RtlCriticalSectionLock);

    if (CriticalSection->DebugInfo)
    {
        /* Free it */
        RtlpFreeDebugInfo(CriticalSection->DebugInfo);
    }

    /* Wipe it out */
    RtlZeroMemory(CriticalSection, sizeof(RTL_CRITICAL_SECTION));

    /* Return */
    return Status;
}

RtlEnterCriticalSection()

NTSTATUS NTAPI RtlEnterCriticalSection

(

PRTL_CRITICAL_SECTION

CriticalSection

)

Definition at line 485 of file critical.c.

{
    HANDLE Thread = (HANDLE)NtCurrentTeb()->ClientId.UniqueThread;

    /* Try to lock it */
    if (InterlockedIncrement(&CriticalSection->LockCount) != 0)
    {
        /* We've failed to lock it! Does this thread actually own it? */
        if (Thread == CriticalSection->OwningThread)
        {
            /*
             * You own it, so you'll get it when you're done with it! No need to
             * use the interlocked functions as only the thread who already owns
             * the lock can modify this data.
             */
            CriticalSection->RecursionCount++;
            return STATUS_SUCCESS;
        }

        /* NOTE - CriticalSection->OwningThread can be NULL here because changing
                  this information is not serialized. This happens when thread a
                  acquires the lock (LockCount == 0) and thread b tries to
                  acquire it as well (LockCount == 1) but thread a hasn't had a
                  chance to set the OwningThread! So it's not an error when
                  OwningThread is NULL here! */

        /* We don't own it, so we must wait for it */
        RtlpWaitForCriticalSection(CriticalSection);
    }

    /*
     * Lock successful. Changing this information has not to be serialized
     * because only one thread at a time can actually change it (the one who
     * acquired the lock)!
     */
    CriticalSection->OwningThread = Thread;
    CriticalSection->RecursionCount = 1;
    return STATUS_SUCCESS;
}

Referenced by RtlDeleteCriticalSection(), and RtlInitializeCriticalSectionAndSpinCount().

RtlGetCriticalSectionRecursionCount()

LONG NTAPI RtlGetCriticalSectionRecursionCount

(

PRTL_CRITICAL_SECTION

CriticalSection

)

Definition at line 657 of file critical.c.

{
    if (CriticalSection->OwningThread == NtCurrentTeb()->ClientId.UniqueThread)
    {
        /*
         * The critical section is owned by the current thread,
         * therefore retrieve its actual recursion count.
         */
        return CriticalSection->RecursionCount;
    }
    else
    {
        /*
         * It is not owned by the current thread, so
         * for this thread there is no recursion.
         */
        return 0;
    }
}

RtlInitializeCriticalSection()

NTSTATUS NTAPI RtlInitializeCriticalSection

(

PRTL_CRITICAL_SECTION

CriticalSection

)

Definition at line 543 of file critical.c.

{
    /* Call the Main Function */
    return RtlInitializeCriticalSectionAndSpinCount(CriticalSection, 0);
}

Referenced by RtlpInitDeferedCriticalSection().

RtlInitializeCriticalSectionAndSpinCount()

NTSTATUS NTAPI RtlInitializeCriticalSectionAndSpinCount	(	PRTL_CRITICAL_SECTION	CriticalSection,
		ULONG	SpinCount
	)

Definition at line 569 of file critical.c.

{
    PRTL_CRITICAL_SECTION_DEBUG CritcalSectionDebugData;

    /* First things first, set up the Object */
    DPRINT("Initializing Critical Section: %p\n", CriticalSection);
    CriticalSection->LockCount = -1;
    CriticalSection->RecursionCount = 0;
    CriticalSection->OwningThread = 0;
    CriticalSection->SpinCount = (NtCurrentPeb()->NumberOfProcessors > 1) ? SpinCount : 0;
    CriticalSection->LockSemaphore = 0;

    /* Allocate the Debug Data */
    CritcalSectionDebugData = RtlpAllocateDebugInfo();
    DPRINT("Allocated Debug Data: %p inside Process: %p\n",
           CritcalSectionDebugData,
           NtCurrentTeb()->ClientId.UniqueProcess);

    if (!CritcalSectionDebugData)
    {
        /* This is bad! */
        DPRINT1("Couldn't allocate Debug Data for: %p\n", CriticalSection);
        return STATUS_NO_MEMORY;
    }

    /* Set it up */
    CritcalSectionDebugData->Type = RTL_CRITSECT_TYPE;
    CritcalSectionDebugData->ContentionCount = 0;
    CritcalSectionDebugData->EntryCount = 0;
    CritcalSectionDebugData->CriticalSection = CriticalSection;
    CritcalSectionDebugData->Flags = 0;
    CriticalSection->DebugInfo = CritcalSectionDebugData;

    /*
     * Add it to the List of Critical Sections owned by the process.
     * If we've initialized the Lock, then use it. If not, then probably
     * this is the lock initialization itself, so insert it directly.
     */
    if ((CriticalSection != &RtlCriticalSectionLock) && (RtlpCritSectInitialized))
    {
        DPRINT("Securely Inserting into ProcessLocks: %p, %p, %p\n",
               &CritcalSectionDebugData->ProcessLocksList,
               CriticalSection,
               &RtlCriticalSectionList);

        /* Protect List */
        RtlEnterCriticalSection(&RtlCriticalSectionLock);

        /* Add this one */
        InsertTailList(&RtlCriticalSectionList, &CritcalSectionDebugData->ProcessLocksList);

        /* Unprotect */
        RtlLeaveCriticalSection(&RtlCriticalSectionLock);
    }
    else
    {
        DPRINT("Inserting into ProcessLocks: %p, %p, %p\n",
               &CritcalSectionDebugData->ProcessLocksList,
               CriticalSection,
               &RtlCriticalSectionList);

        /* Add it directly */
        InsertTailList(&RtlCriticalSectionList, &CritcalSectionDebugData->ProcessLocksList);
    }

    return STATUS_SUCCESS;
}

Referenced by RtlInitializeCriticalSection().

RtlIsCriticalSectionLocked()

ULONG NTAPI RtlIsCriticalSectionLocked

(

PRTL_CRITICAL_SECTION

CriticalSection

)

Definition at line 791 of file critical.c.

{
    return CriticalSection->RecursionCount != 0;
}

RtlIsCriticalSectionLockedByThread()

ULONG NTAPI RtlIsCriticalSectionLockedByThread

(

PRTL_CRITICAL_SECTION

CriticalSection

)

Definition at line 798 of file critical.c.

{
    return CriticalSection->OwningThread == NtCurrentTeb()->ClientId.UniqueThread &&
           CriticalSection->RecursionCount != 0;
}

RtlLeaveCriticalSection()

NTSTATUS NTAPI RtlLeaveCriticalSection

(

PRTL_CRITICAL_SECTION

CriticalSection

)

Definition at line 695 of file critical.c.

{
#if DBG
    HANDLE Thread = (HANDLE)NtCurrentTeb()->ClientId.UniqueThread;

    /*
     * In win this case isn't checked. However it's a valid check so it should
     * only be performed in debug builds!
     */
    if (Thread != CriticalSection->OwningThread)
    {
       DPRINT1("Releasing critical section not owned!\n");
       return STATUS_INVALID_PARAMETER;
    }
#endif

    /*
     * Decrease the Recursion Count. No need to do this atomically because only
     * the thread who holds the lock can call this function (unless the program
     * is totally screwed...
     */
    if (--CriticalSection->RecursionCount)
    {
        /* Someone still owns us, but we are free. This needs to be done atomically. */
        InterlockedDecrement(&CriticalSection->LockCount);

    }
    else
    {
        /*
         * Nobody owns us anymore. No need to do this atomically.
         * See comment above.
         */
        CriticalSection->OwningThread = 0;

        /* Was someone wanting us? This needs to be done atomically. */
        if (-1 != InterlockedDecrement(&CriticalSection->LockCount))
        {
            /* Let him have us */
            RtlpUnWaitCriticalSection(CriticalSection);
        }
    }

    /* Sucessful! */
    return STATUS_SUCCESS;
}

Referenced by RtlDeleteCriticalSection(), and RtlInitializeCriticalSectionAndSpinCount().

RtlpAllocateDebugInfo()

PRTL_CRITICAL_SECTION_DEBUG NTAPI RtlpAllocateDebugInfo

(

VOID

)

Definition at line 297 of file critical.c.

{
    ULONG i;

    /* Try to allocate from our buffer first */
    for (i = 0; i < MAX_STATIC_CS_DEBUG_OBJECTS; i++)
    {
        /* Check if Entry is free */
        if (!RtlpDebugInfoFreeList[i])
        {
            /* Mark entry in use */
            DPRINT("Using entry: %lu. Buffer: %p\n", i, &RtlpStaticDebugInfo[i]);
            RtlpDebugInfoFreeList[i] = TRUE;

            /* Use free entry found */
            return &RtlpStaticDebugInfo[i];
        }
    }

    /* We are out of static buffer, allocate dynamic */
    return RtlAllocateHeap(RtlGetProcessHeap(),
                           0,
                           sizeof(RTL_CRITICAL_SECTION_DEBUG));
}

Referenced by RtlInitializeCriticalSectionAndSpinCount().

RtlpFreeDebugInfo()

VOID NTAPI RtlpFreeDebugInfo

(

PRTL_CRITICAL_SECTION_DEBUG

DebugInfo

)

Definition at line 340 of file critical.c.

{
    SIZE_T EntryId;

    /* Is it part of our cached entries? */
    if ((DebugInfo >= RtlpStaticDebugInfo) &&
        (DebugInfo <= &RtlpStaticDebugInfo[MAX_STATIC_CS_DEBUG_OBJECTS-1]))
    {
        /* Yes. zero it out */
        RtlZeroMemory(DebugInfo, sizeof(RTL_CRITICAL_SECTION_DEBUG));

        /* Mark as free */
        EntryId = (DebugInfo - RtlpStaticDebugInfo);
        DPRINT("Freeing from Buffer: %p. Entry: %Iu inside Process: %p\n",
               DebugInfo,
               EntryId,
               NtCurrentTeb()->ClientId.UniqueProcess);
        RtlpDebugInfoFreeList[EntryId] = FALSE;

    }
    else if (!DebugInfo->Flags)
    {
        /* It's a dynamic one, so free from the heap */
        DPRINT("Freeing from Heap: %p inside Process: %p\n",
               DebugInfo,
               NtCurrentTeb()->ClientId.UniqueProcess);
        RtlFreeHeap(NtCurrentPeb()->ProcessHeap, 0, DebugInfo);
    }
    else
    {
        /* Wine stores a section name pointer in the Flags member */
        DPRINT("Assuming static: %p inside Process: %p\n",
               DebugInfo,
               NtCurrentTeb()->ClientId.UniqueProcess);
    }
}

Referenced by RtlDeleteCriticalSection().

RtlpInitDeferedCriticalSection()

VOID NTAPI RtlpInitDeferedCriticalSection

(

VOID

)

Definition at line 267 of file critical.c.

{
    /* Initialize the Process Critical Section List */
    InitializeListHead(&RtlCriticalSectionList);

    /* Initialize the CS Protecting the List */
    RtlInitializeCriticalSection(&RtlCriticalSectionLock);

    /* It's now safe to enter it */
    RtlpCritSectInitialized = TRUE;
}

Referenced by LdrpInitializeProcess().

RtlpUnWaitCriticalSection()

VOID NTAPI RtlpUnWaitCriticalSection

(

PRTL_CRITICAL_SECTION

CriticalSection

)

Definition at line 212 of file critical.c.

{
    NTSTATUS Status;

    /* Do we have an Event yet? */
    if (!CriticalSection->LockSemaphore)
    {
        RtlpCreateCriticalSectionSem(CriticalSection);
    }

    /* Signal the Event */
    DPRINT("Signaling Critical Section Event: %p, %p\n",
            CriticalSection,
            CriticalSection->LockSemaphore);

    /* Check if this critical section needs to use the keyed event */
    if (CriticalSection->LockSemaphore == INVALID_HANDLE_VALUE)
    {
        /* Release keyed event */
        Status = NtReleaseKeyedEvent(NULL, CriticalSection, FALSE, &RtlpTimeout);
    }
    else
    {
        /* Set the event */
        Status = NtSetEvent(CriticalSection->LockSemaphore, NULL);
    }

    if (!NT_SUCCESS(Status))
    {
        /* We've failed */
        DPRINT1("Signaling Failed for: %p, %p, 0x%08lx\n",
                CriticalSection,
                CriticalSection->LockSemaphore,
                Status);
        RtlRaiseStatus(Status);
    }
}

Referenced by RtlLeaveCriticalSection().

RtlpWaitForCriticalSection()

NTSTATUS NTAPI RtlpWaitForCriticalSection

(

PRTL_CRITICAL_SECTION

CriticalSection

)

Definition at line 111 of file critical.c.

{
    NTSTATUS Status;
    EXCEPTION_RECORD ExceptionRecord;
    BOOLEAN LastChance = FALSE;

    /* Do we have an Event yet? */
    if (!CriticalSection->LockSemaphore)
    {
        RtlpCreateCriticalSectionSem(CriticalSection);
    }

    /* Increase the Debug Entry count */
    DPRINT("Waiting on Critical Section Event: %p %p\n",
            CriticalSection,
            CriticalSection->LockSemaphore);

    if (CriticalSection->DebugInfo)
        CriticalSection->DebugInfo->EntryCount++;

    /*
     * If we're shutting down the process, we're allowed to acquire any
     * critical sections by force (the loader lock in particular)
     */
    if (LdrpShutdownInProgress &&
        LdrpShutdownThreadId == NtCurrentTeb()->RealClientId.UniqueThread)
    {
        DPRINT("Forcing ownership of critical section %p\n", CriticalSection);
        CriticalSection->LockCount = 0;
        return STATUS_SUCCESS;
    }

    for (;;)
    {
        /* Increase the number of times we've had contention */
        if (CriticalSection->DebugInfo)
            CriticalSection->DebugInfo->ContentionCount++;

        /* Check if allocating the event failed */
        if (CriticalSection->LockSemaphore == INVALID_HANDLE_VALUE)
        {
            /* Use the global keyed event (NULL as keyed event handle) */
            Status = NtWaitForKeyedEvent(NULL,
                                         CriticalSection,
                                         FALSE,
                                         &RtlpTimeout);
        }
        else
        {
            /* Wait on the Event */
            Status = NtWaitForSingleObject(CriticalSection->LockSemaphore,
                                           FALSE,
                                           &RtlpTimeout);
        }

        /* We have Timed out */
        if (Status == STATUS_TIMEOUT)
        {
            /* Is this the 2nd time we've timed out? */
            if (LastChance)
            {
                ERROR_DBGBREAK("Deadlock: 0x%p\n", CriticalSection);

                /* Yes it is, we are raising an exception */
                ExceptionRecord.ExceptionCode    = STATUS_POSSIBLE_DEADLOCK;
                ExceptionRecord.ExceptionFlags   = 0;
                ExceptionRecord.ExceptionRecord  = NULL;
                ExceptionRecord.ExceptionAddress = RtlRaiseException;
                ExceptionRecord.NumberParameters = 1;
                ExceptionRecord.ExceptionInformation[0] = (ULONG_PTR)CriticalSection;
                RtlRaiseException(&ExceptionRecord);
            }

            /* One more try */
            LastChance = TRUE;
        }
        else
        {
            /* If we are here, everything went fine */
            return STATUS_SUCCESS;
        }
    }
}

Referenced by RtlEnterCriticalSection().

RtlSetCriticalSectionSpinCount()

ULONG NTAPI RtlSetCriticalSectionSpinCount	(	PRTL_CRITICAL_SECTION	CriticalSection,
		ULONG	SpinCount
	)

Definition at line 457 of file critical.c.

{
    ULONG OldCount = (ULONG)CriticalSection->SpinCount;

    /* Set to parameter if MP, or to 0 if this is Uniprocessor */
    CriticalSection->SpinCount = (NtCurrentPeb()->NumberOfProcessors > 1) ? SpinCount : 0;
    return OldCount;
}

RtlTryEnterCriticalSection()

BOOLEAN NTAPI RtlTryEnterCriticalSection

(

PRTL_CRITICAL_SECTION

CriticalSection

)

Definition at line 760 of file critical.c.

{
    /* Try to take control */
    if (InterlockedCompareExchange(&CriticalSection->LockCount, 0, -1) == -1)
    {
        /* It's ours */
        CriticalSection->OwningThread =  NtCurrentTeb()->ClientId.UniqueThread;
        CriticalSection->RecursionCount = 1;
        return TRUE;
    }
    else if (CriticalSection->OwningThread == NtCurrentTeb()->ClientId.UniqueThread)
    {
        /* It's already ours */
        InterlockedIncrement(&CriticalSection->LockCount);
        CriticalSection->RecursionCount++;
        return TRUE;
    }

    /* It's not ours */
    return FALSE;
}

Variable Documentation

LdrpShutdownInProgress

BOOLEAN LdrpShutdownInProgress

Definition at line 34 of file ldrinit.c.

Referenced by LdrpInitializeThread(), LdrShutdownProcess(), LdrShutdownThread(), and RtlpWaitForCriticalSection().

LdrpShutdownThreadId

HANDLE LdrpShutdownThreadId

Definition at line 35 of file ldrinit.c.

Referenced by LdrShutdownProcess(), and RtlpWaitForCriticalSection().

RtlCriticalSectionList

LIST_ENTRY RtlCriticalSectionList

static

Definition at line 20 of file critical.c.

Referenced by RtlInitializeCriticalSectionAndSpinCount(), and RtlpInitDeferedCriticalSection().

RtlCriticalSectionLock

RTL_CRITICAL_SECTION RtlCriticalSectionLock

static

Definition at line 19 of file critical.c.

Referenced by RtlDeleteCriticalSection(), RtlInitializeCriticalSectionAndSpinCount(), and RtlpInitDeferedCriticalSection().

RtlpCritSectInitialized

BOOLEAN RtlpCritSectInitialized = FALSE

static

Definition at line 21 of file critical.c.

Referenced by RtlInitializeCriticalSectionAndSpinCount(), and RtlpInitDeferedCriticalSection().

RtlpDebugInfoFreeList

BOOLEAN RtlpDebugInfoFreeList[MAX_STATIC_CS_DEBUG_OBJECTS]

static

Definition at line 23 of file critical.c.

Referenced by RtlpAllocateDebugInfo(), and RtlpFreeDebugInfo().

RtlpStaticDebugInfo

RTL_CRITICAL_SECTION_DEBUG RtlpStaticDebugInfo[MAX_STATIC_CS_DEBUG_OBJECTS]

static

Definition at line 22 of file critical.c.

Referenced by RtlpAllocateDebugInfo(), and RtlpFreeDebugInfo().

RtlpTimeout

LARGE_INTEGER RtlpTimeout

Definition at line 24 of file critical.c.

Referenced by LdrpInitializeProcess(), RtlpUnWaitCriticalSection(), and RtlpWaitForCriticalSection().