fls.c File Reference

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

Include dependency graph for fls.c:

Go to the source code of this file.

Classes
struct	_FLS_CALLBACK_INFO

Macros
#define	NDEBUG

Typedefs
typedef struct _FLS_CALLBACK_INFO	FLS_CALLBACK_INFO
typedef struct _FLS_CALLBACK_INFO *	PFLS_CALLBACK_INFO

Functions
static VOID	RtlpAcquireFlsLock (VOID)
static VOID	RtlpReleaseFlsLock (VOID)
static NTSTATUS	RtlpAllocateFlsCallbackArray (VOID)
static NTSTATUS	RtlpAllocateThreadFlsData (VOID)
NTSTATUS NTAPI	RtlFlsAllocEx (_In_ PFLS_CALLBACK_FUNCTION Callback, _Out_opt_ PULONG Unknown, _Out_ PULONG FlsIndex)
NTSTATUS NTAPI	RtlFlsAlloc (_In_ PFLS_CALLBACK_FUNCTION Callback, _Out_ PULONG FlsIndex)
NTSTATUS NTAPI	RtlFlsFree (_In_ ULONG FlsIndex)
NTSTATUS NTAPI	RtlProcessFlsData (_In_ HANDLE ProcessHandle, _Out_ PVOID *FlsData)
NTSTATUS NTAPI	RtlFlsGetValue (_In_ ULONG FlsIndex, _Out_ PVOID *FlsData)
PVOID WINAPI	RtlFlsGetValue2 (_In_ ULONG FlsIndex)
NTSTATUS NTAPI	RtlFlsSetValue (_In_ ULONG FlsIndex, _In_ PVOID FlsData)

Macro Definition Documentation

NDEBUG

#define NDEBUG

Definition at line 10 of file fls.c.

Typedef Documentation

FLS_CALLBACK_INFO

typedef struct _FLS_CALLBACK_INFO FLS_CALLBACK_INFO

PFLS_CALLBACK_INFO

typedef struct _FLS_CALLBACK_INFO * PFLS_CALLBACK_INFO

Function Documentation

RtlFlsAlloc()

NTSTATUS NTAPI RtlFlsAlloc	(	_In_ PFLS_CALLBACK_FUNCTION	Callback,
		_Out_ PULONG	FlsIndex
	)

Definition at line 174 of file fls.c.

{
    return RtlFlsAllocEx(Callback, NULL, FlsIndex);
}

RtlFlsAllocEx()

NTSTATUS NTAPI RtlFlsAllocEx	(	_In_ PFLS_CALLBACK_FUNCTION	Callback,
		_Out_opt_ PULONG	Unknown,
		_Out_ PULONG	FlsIndex
	)

Definition at line 116 of file fls.c.

{
    PPEB peb = NtCurrentPeb();
    PTEB teb = NtCurrentTeb();
    NTSTATUS status;
    ULONG index;
 
    /* Check if we have a thread FLS data structure */
    if (teb->FlsData == NULL)
    {
        /* Allocate a new thread FLS data structure */
        status = RtlpAllocateThreadFlsData();
        if (!NT_SUCCESS(status))
        {
            return status;
        }
    }
 
    /* Check if we need to allocate the callback array */
    if (peb->FlsCallback == NULL)
    {
        status = RtlpAllocateFlsCallbackArray();
        if (!NT_SUCCESS(status))
        {
            return status;
        }
    }
 
    RtlpAcquireFlsLock();
 
    /* Find a free index */
    index = RtlFindClearBitsAndSet(peb->FlsBitmap, 1, 0);
    if (index == -1)
    {
        RtlpReleaseFlsLock();
        return STATUS_NO_MEMORY;
    }
 
    /* Set the callback */
    PFLS_CALLBACK_INFO callbacks = (PFLS_CALLBACK_INFO)peb->FlsCallback;
    callbacks[index].Callback = Callback;
 
    /* Update high index */
    peb->FlsHighIndex = max(peb->FlsHighIndex, index);
 
    RtlpReleaseFlsLock();
 
    /* Return the index */
    *FlsIndex = index;
 
    return STATUS_SUCCESS;
}

Referenced by InitFunctionPtrs(), and RtlFlsAlloc().

RtlFlsFree()

NTSTATUS NTAPI RtlFlsFree

(

_In_ ULONG

FlsIndex

)

Definition at line 183 of file fls.c.

{
    PPEB peb = NtCurrentPeb();
    PRTL_BITMAP flsBitmap = peb->FlsBitmap;
 
    /* Check if the FLS index is within the valid range */
    if ((FlsIndex == 0) || (FlsIndex >= FLS_MAXIMUM_AVAILABLE))
    {
        return STATUS_INVALID_PARAMETER;
    }
 
    RtlpAcquireFlsLock();
 
    /* Validate that the bit is set */
    if (!RtlCheckBit(flsBitmap, FlsIndex))
    {
        RtlpReleaseFlsLock();
        return STATUS_INVALID_PARAMETER;
    }
 
    /* Check if there is a callback */
    PFLS_CALLBACK_INFO callbackArray = (PFLS_CALLBACK_INFO)peb->FlsCallback;
    PFLS_CALLBACK_FUNCTION callbackFunction = callbackArray[FlsIndex].Callback;
 
    /* Clear the FLS index bit */
    RtlClearBit(peb->FlsBitmap, FlsIndex);
 
    /* Protect with SEH to guard against a broken callback.
       Note: Vista doesn't do that and will leak the FLS lock!
       Windows 10 protects the lock and still manages to clear the values as well.
       We replicate Windows 10 behavior. */
    _SEH2_VOLATILE PLIST_ENTRY listEntry;
    _SEH2_TRY
    {
        /* Loop all thread FLS data structures */
        for (listEntry = peb->FlsListHead.Flink;
             listEntry != &peb->FlsListHead;
             listEntry = listEntry->Flink)
        {
            /* Get the thread FLS data structure */
            PRTL_FLS_DATA flsData = CONTAINING_RECORD(listEntry, RTL_FLS_DATA, ListEntry);
 
            /* Check if the value is set (!= NULL) */
            if (flsData->Data[FlsIndex] != NULL)
            {
                if (callbackFunction != NULL)
                {
                    callbackFunction(flsData->Data[FlsIndex]);
                }
 
                flsData->Data[FlsIndex] = NULL;
            }
        }
 
        /* Clear the callback */
        callbackArray[FlsIndex].Callback = NULL;
    }
    _SEH2_FINALLY
    {
        /* Check if we got an exception */
        if (_SEH2_AbnormalTermination())
        {
            /* We need to finish clearing the values */
            for (/* the current entry */;
                 listEntry != &peb->FlsListHead;
                 listEntry = listEntry->Flink)
            {
                /* Get the thread FLS data structure and clear the value */
                PRTL_FLS_DATA flsData = CONTAINING_RECORD(listEntry, RTL_FLS_DATA, ListEntry);
                flsData->Data[FlsIndex] = NULL;
            }
 
            /* Clear the callback */
            callbackArray[FlsIndex].Callback = NULL;
        }
 
        RtlpReleaseFlsLock();
    }
    _SEH2_END;
 
    return STATUS_SUCCESS;
}

RtlFlsGetValue()

NTSTATUS NTAPI RtlFlsGetValue	(	_In_ ULONG	FlsIndex,
		_Out_ PVOID *	FlsData
	)

Definition at line 295 of file fls.c.

{
    /* Check if the FLS index is within the valid range */
    if ((FlsIndex == 0) || (FlsIndex >= FLS_MAXIMUM_AVAILABLE))
    {
        return STATUS_INVALID_PARAMETER;
    }
 
    /* Check if we have a thread FLS data structure */
    PTEB teb = NtCurrentTeb();
    if (teb->FlsData == NULL)
    {
        return ERROR_INVALID_PARAMETER;
    }
 
    /* Return the value (the function doesnt check the bitmap!) */
    PRTL_FLS_DATA flsData = teb->FlsData;
    *FlsData = flsData->Data[FlsIndex];
 
    return STATUS_SUCCESS;
}

Referenced by RtlFlsGetValue2().

RtlFlsGetValue2()

PVOID WINAPI RtlFlsGetValue2

(

_In_ ULONG

FlsIndex

)

Definition at line 322 of file fls.c.

{
    NTSTATUS status;
    PVOID flsData;
 
    status = RtlFlsGetValue(FlsIndex, &flsData);
    if (!NT_SUCCESS(status))
    {
        return NULL;
    }
 
    return flsData;
}

Referenced by InitFunctionPtrs().

RtlFlsSetValue()

NTSTATUS NTAPI RtlFlsSetValue	(	_In_ ULONG	FlsIndex,
		_In_ PVOID	FlsData
	)

Definition at line 340 of file fls.c.

{
    NTSTATUS status;
 
    /* Check if the FLS index is within the valid range */
    if ((FlsIndex == 0) || (FlsIndex >= FLS_MAXIMUM_AVAILABLE))
    {
        return STATUS_INVALID_PARAMETER;
    }
 
    /* Check if we have a thread FLS data structure */
    PTEB teb = NtCurrentTeb();
    if (teb->FlsData == NULL)
    {
        /* Allocate a new thread FLS data structure */
        status = RtlpAllocateThreadFlsData();
        if (!NT_SUCCESS(status))
        {
            return status;
        }
    }
 
    /* Set the value (the function doesnt check the bitmap!) */
    PRTL_FLS_DATA flsData = teb->FlsData;
    flsData->Data[FlsIndex] = FlsData;
 
    return STATUS_SUCCESS;
}

RtlpAcquireFlsLock()

static VOID RtlpAcquireFlsLock ( VOID  )

static

Definition at line 33 of file fls.c.

{
    /* Acquire the lock */
    //RtlAcquireSRWLockExclusive(&RtlpFlsLock);
    RtlAcquirePebLock();
}

Referenced by RtlFlsAllocEx(), RtlFlsFree(), RtlpAllocateFlsCallbackArray(), and RtlpAllocateThreadFlsData().

RtlpAllocateFlsCallbackArray()

static NTSTATUS RtlpAllocateFlsCallbackArray ( VOID  )

static

Definition at line 51 of file fls.c.

{
    PPEB peb = NtCurrentPeb();
    PVOID* newCallbacks;
 
    /* Allocate a new callback array */
    newCallbacks = RtlAllocateHeap(RtlGetProcessHeap(),
                                   HEAP_ZERO_MEMORY,
                                   RTL_FLS_MAXIMUM_AVAILABLE * sizeof(FLS_CALLBACK_INFO));
    if (newCallbacks == NULL)
    {
        return STATUS_NO_MEMORY;
    }
 
    RtlpAcquireFlsLock();
 
    if (peb->FlsCallback == NULL)
    {
        peb->FlsCallback = newCallbacks;
        newCallbacks = NULL;
    }
 
    RtlpReleaseFlsLock();
 
    /* Clean up, if needed */
    if (newCallbacks != NULL)
    {
        RtlFreeHeap(RtlGetProcessHeap(), 0, newCallbacks);
    }
 
    return STATUS_SUCCESS;
}

Referenced by RtlFlsAllocEx().

RtlpAllocateThreadFlsData()

static NTSTATUS RtlpAllocateThreadFlsData ( VOID  )

static

Definition at line 86 of file fls.c.

{
    PTEB teb = NtCurrentTeb();
    PRTL_FLS_DATA newFlsData;
 
    ASSERT(teb->FlsData == NULL);
 
    /* Allocate a new thread FLS data structure */
    newFlsData = RtlAllocateHeap(RtlGetProcessHeap(),
                                 HEAP_ZERO_MEMORY,
                                 sizeof(RTL_FLS_DATA));
    if (newFlsData == NULL)
    {
        return STATUS_NO_MEMORY;
    }
 
    PPEB peb = NtCurrentPeb();
 
    RtlpAcquireFlsLock();
    InsertTailList(&peb->FlsListHead, &newFlsData->ListEntry);
    RtlpReleaseFlsLock();
 
    teb->FlsData = newFlsData;
 
    return STATUS_SUCCESS;
}

Referenced by RtlFlsAllocEx(), and RtlFlsSetValue().

RtlpReleaseFlsLock()

static VOID RtlpReleaseFlsLock ( VOID  )

static

Definition at line 42 of file fls.c.

{
    /* Release the lock */
    //RtlReleaseSRWLockExclusive(&RtlpFlsLock);
    RtlReleasePebLock();
}

Referenced by RtlFlsAllocEx(), RtlFlsFree(), RtlpAllocateFlsCallbackArray(), and RtlpAllocateThreadFlsData().

RtlProcessFlsData()

NTSTATUS NTAPI RtlProcessFlsData	(	_In_ HANDLE	ProcessHandle,
		_Out_ PVOID *	FlsData
	)

Definition at line 282 of file fls.c.

{
    return STATUS_NOT_IMPLEMENTED;
}