#include "fltmgr.h"
#include "fltmgrint.h"
#include <debug.h>

Include dependency graph for Object.c:

Macros
#define	NDEBUG

#define	ExpChangePushlock(x, y, z) InterlockedCompareExchangePointer((PVOID*)x, (PVOID)y, (PVOID)z)

#define	EX_PUSH_LOCK_LOCK_V ((ULONG_PTR)0x0)

#define	EX_PUSH_LOCK_LOCK ((ULONG_PTR)0x1)

#define	EX_PUSH_LOCK_WAITING ((ULONG_PTR)0x2)

#define	EX_PUSH_LOCK_WAKING ((ULONG_PTR)0x4)

#define	EX_PUSH_LOCK_MULTIPLE_SHARED ((ULONG_PTR)0x8)

#define	EX_PUSH_LOCK_SHARE_INC ((ULONG_PTR)0x10)

#define	EX_PUSH_LOCK_PTR_BITS ((ULONG_PTR)0xf)

Functions
NTSTATUS FLTAPI	FltObjectReference (_Inout_ PVOID Object)

VOID FLTAPI	FltObjectDereference (_Inout_ PVOID Object)

	_Acquires_lock_ (_Global_critical_region_)

	_Releases_lock_ (_Global_critical_region_)

	_IRQL_requires_max_ (PASSIVE_LEVEL)

VOID	FltpExInitializeRundownProtection (_Out_ PEX_RUNDOWN_REF RundownRef)

BOOLEAN	FltpExAcquireRundownProtection (_Inout_ PEX_RUNDOWN_REF RundownRef)

BOOLEAN	FltpExReleaseRundownProtection (_Inout_ PEX_RUNDOWN_REF RundownRef)

BOOLEAN	FltpExRundownCompleted (_Inout_ PEX_RUNDOWN_REF RundownRef)

NTSTATUS NTAPI	FltpObjectRundownWait (_Inout_ PEX_RUNDOWN_REF RundownRef)

NTSTATUS	FltpGetBaseDeviceObjectName (_In_ PDEVICE_OBJECT DeviceObject, _Inout_ PUNICODE_STRING ObjectName)

NTSTATUS	FltpGetObjectName (_In_ PVOID Object, _Inout_ PUNICODE_STRING ObjectName)

ULONG	FltpObjectPointerReference (_In_ PFLT_OBJECT Object)

VOID	FltpObjectPointerDereference (_In_ PFLT_OBJECT Object)

Macro Definition Documentation

◆ EX_PUSH_LOCK_LOCK

#define EX_PUSH_LOCK_LOCK ((ULONG_PTR)0x1)

Definition at line 29 of file Object.c.

◆ EX_PUSH_LOCK_LOCK_V

#define EX_PUSH_LOCK_LOCK_V ((ULONG_PTR)0x0)

Definition at line 28 of file Object.c.

◆ EX_PUSH_LOCK_MULTIPLE_SHARED

#define EX_PUSH_LOCK_MULTIPLE_SHARED ((ULONG_PTR)0x8)

Definition at line 32 of file Object.c.

◆ EX_PUSH_LOCK_PTR_BITS

#define EX_PUSH_LOCK_PTR_BITS ((ULONG_PTR)0xf)

Definition at line 34 of file Object.c.

◆ EX_PUSH_LOCK_SHARE_INC

#define EX_PUSH_LOCK_SHARE_INC ((ULONG_PTR)0x10)

Definition at line 33 of file Object.c.

◆ EX_PUSH_LOCK_WAITING

#define EX_PUSH_LOCK_WAITING ((ULONG_PTR)0x2)

Definition at line 30 of file Object.c.

◆ EX_PUSH_LOCK_WAKING

#define EX_PUSH_LOCK_WAKING ((ULONG_PTR)0x4)

Definition at line 31 of file Object.c.

◆ ExpChangePushlock

#define ExpChangePushlock	(	x,
		y,
		z
	)	InterlockedCompareExchangePointer((PVOID*)x, (PVOID)y, (PVOID)z)

Definition at line 23 of file Object.c.

◆ NDEBUG

#define NDEBUG

Definition at line 17 of file Object.c.

Function Documentation

◆ _Acquires_lock_()

_Acquires_lock_ ( _Global_critical_region_ )

Definition at line 59 of file Object.c.

{
    KeEnterCriticalRegion();
 
    /* Try acquiring the lock */
    if (InterlockedBitTestAndSet((PLONG)PushLock, EX_PUSH_LOCK_LOCK_V))
    {
        /* Someone changed it, use the slow path */
        ExfAcquirePushLockExclusive(PushLock);
    }
 
    /* Sanity check */
    FLT_ASSERT(PushLock->Locked);
}

◆ _IRQL_requires_max_()

_IRQL_requires_max_ ( PASSIVE_LEVEL )

Definition at line 137 of file Object.c.

{
    PAGED_CODE();
 
    return ZwClose(FileHandle);
}

◆ _Releases_lock_()

_Releases_lock_ ( _Global_critical_region_ )

Definition at line 101 of file Object.c.

{
    EX_PUSH_LOCK OldValue = *PushLock;
    EX_PUSH_LOCK NewValue;
 
    /* Sanity checks */
    FLT_ASSERT(OldValue.Locked);
 
    /* Check if the pushlock is shared */
    if (OldValue.Shared > 1)
    {
        /* Decrease the share count */
        NewValue.Value = OldValue.Value - EX_PUSH_LOCK_SHARE_INC;
    }
    else
    {
        /* Clear the pushlock entirely */
        NewValue.Value = 0;
    }
 
    /* Check if nobody is waiting on us and try clearing the lock here */
    if ((OldValue.Waiting) ||
        (ExpChangePushlock(PushLock, NewValue.Ptr, OldValue.Ptr) !=
         OldValue.Ptr))
    {
        /* We have waiters, use the long path */
        ExfReleasePushLock(PushLock);
    }
 
    KeLeaveCriticalRegion();
}

◆ FltObjectDereference()

VOID FLTAPI FltObjectDereference ( _Inout_ PVOID Object )

Definition at line 53 of file Object.c.

{
    FltpExReleaseRundownProtection(&((PFLT_OBJECT)Object)->RundownRef);
}

Referenced by _IRQL_requires_max_(), CreateClientPort(), FltEnumerateVolumes(), FltpServerPortClose(), FltStartFiltering(), and FltUnregisterFilter().

◆ FltObjectReference()

NTSTATUS FLTAPI FltObjectReference ( _Inout_ PVOID Object )

Definition at line 41 of file Object.c.

{
    if (!FltpExAcquireRundownProtection(&((PFLT_OBJECT)Object)->RundownRef))
    {
        return STATUS_FLT_DELETING_OBJECT;
    }
 
    return STATUS_SUCCESS;
}

Referenced by _IRQL_requires_max_(), CreateClientPort(), FltEnumerateVolumes(), FltRegisterFilter(), and FltStartFiltering().

◆ FltpExAcquireRundownProtection()

BOOLEAN FltpExAcquireRundownProtection ( _Inout_ PEX_RUNDOWN_REF RundownRef )

Definition at line 218 of file Object.c.

{
    return ExAcquireRundownProtection(RundownRef);
}

Referenced by FltObjectReference().

◆ FltpExInitializeRundownProtection()

VOID FltpExInitializeRundownProtection ( _Out_ PEX_RUNDOWN_REF RundownRef )

Definition at line 212 of file Object.c.

{
    ExInitializeRundownProtection(RundownRef);
}

Referenced by FltRegisterFilter().

◆ FltpExReleaseRundownProtection()

BOOLEAN FltpExReleaseRundownProtection ( _Inout_ PEX_RUNDOWN_REF RundownRef )

Definition at line 224 of file Object.c.

{
    ExReleaseRundownProtection(RundownRef);
    return TRUE;
}

Referenced by FltObjectDereference().

◆ FltpExRundownCompleted()

BOOLEAN FltpExRundownCompleted ( _Inout_ PEX_RUNDOWN_REF RundownRef )

Definition at line 231 of file Object.c.

{
    return _InterlockedExchange((PLONG)RundownRef, 1);
}

Referenced by FltUnregisterFilter().

◆ FltpGetBaseDeviceObjectName()

NTSTATUS FltpGetBaseDeviceObjectName	(	_In_ PDEVICE_OBJECT	DeviceObject,
		_Inout_ PUNICODE_STRING	ObjectName
	)

Definition at line 245 of file Object.c.

{
    PDEVICE_OBJECT BaseDeviceObject;
    NTSTATUS Status;
 
    /*
    * Get the lowest device object on the stack, which may be the
    * object we were passed, and lookup the name for that object
    */
    BaseDeviceObject = IoGetDeviceAttachmentBaseRef(DeviceObject);
    Status = FltpGetObjectName(BaseDeviceObject, ObjectName);
    ObDereferenceObject(BaseDeviceObject);
 
    return Status;
}

Referenced by FltpEnumerateFileSystemVolumes(), and FltpFsNotification().

◆ FltpGetObjectName()

NTSTATUS FltpGetObjectName	(	_In_ PVOID	Object,
		_Inout_ PUNICODE_STRING	ObjectName
	)

Definition at line 263 of file Object.c.

{
    OBJECT_NAME_INFORMATION LocalNameInfo;
    POBJECT_NAME_INFORMATION ObjectNameInfo = &LocalNameInfo;
    ULONG ReturnLength;
    NTSTATUS Status;
 
    if (ObjectName == NULL)
        return STATUS_INVALID_PARAMETER;
 
    /* Get the size of the buffer required to hold the nameinfo */
    Status = ObQueryNameString(Object,
                               &LocalNameInfo,
                               sizeof(LocalNameInfo),
                               &ReturnLength);
    if (Status == STATUS_INFO_LENGTH_MISMATCH)
    {
        ObjectNameInfo = ExAllocatePoolWithTag(PagedPool,
                                               ReturnLength,
                                               FM_TAG_UNICODE_STRING);
        if (ObjectNameInfo == NULL) return STATUS_INSUFFICIENT_RESOURCES;
 
        /* Get the actual name info now we have the buffer to hold it */
        Status = ObQueryNameString(Object,
                                   ObjectNameInfo,
                                   ReturnLength,
                                   &ReturnLength);
    }
 
 
    if (NT_SUCCESS(Status))
    {
        /* Make sure the buffer we were passed is large enough to hold the string */
        if (ObjectName->MaximumLength < ObjectNameInfo->Name.Length)
        {
            /* It wasn't, let's enlarge the buffer */
            Status = FltpReallocateUnicodeString(ObjectName,
                                                 ObjectNameInfo->Name.Length,
                                                 FALSE);
 
        }
 
        if (NT_SUCCESS(Status))
        {
            /* Copy the object name into the callers buffer */
            RtlCopyUnicodeString(ObjectName, &ObjectNameInfo->Name);
        }
    }
 
    if (ObjectNameInfo != &LocalNameInfo)
    {
        ExFreePoolWithTag(ObjectNameInfo, FM_TAG_UNICODE_STRING);
    }
 
    return Status;
}

Referenced by FltpAttachToFileSystemDevice(), FltpEnumerateFileSystemVolumes(), and FltpGetBaseDeviceObjectName().

◆ FltpObjectPointerDereference()

VOID FltpObjectPointerDereference ( _In_ PFLT_OBJECT Object )

Definition at line 335 of file Object.c.

{
    if (InterlockedDecrementSizeT(&Object->PointerCount) == 0)
    {
        // Cleanup
        FLT_ASSERT(FALSE);
    }
}

Referenced by FltpServerPortDelete().

◆ FltpObjectPointerReference()

ULONG FltpObjectPointerReference ( _In_ PFLT_OBJECT Object )

Definition at line 322 of file Object.c.

{
    PULONG Result;
 
    /* Store the old count and increment */
    Result = &Object->PointerCount;
    InterlockedIncrementSizeT(&Object->PointerCount);
 
    /* Return the initial value */
    return *Result;
}

Referenced by _IRQL_requires_max_().

◆ FltpObjectRundownWait()

NTSTATUS NTAPI FltpObjectRundownWait ( _Inout_ PEX_RUNDOWN_REF RundownRef )

Definition at line 238 of file Object.c.

{
    //return FltpExWaitForRundownProtectionRelease(RundownRef);
    return 0;
}