/*
* PROJECT: Alcyone  Kernel
* LICENSE: BSD Clause 3 
* PURPOSE: Cache Controller:: MDL Handler   
* NT KERNEL: 5.11.9360 
* COPYRIGHT: 2023-2029 Dibymartanda Samanta <>
*             
*/
#include <ntoskrnl.h>
#define NTDEBUG
#include <debug.h>
#include "ccinternal.hpp"
#include "ccmdl.hpp"


extern "C"

/*Internal Function*/

VOID
NTAPI
CcMdlReadComplete2 (
    IN PFILE_OBJECT FileObject,
    IN PMDL MdlChain
)
{
	 /* Check if MDL Chain is Valid */
	if (MdlChain)
	{    
        /*Iterate Through the MDL CHain*/
        for( auto it = begin(MdlChain); it != end(MdlChain);++it)
		{    
	        /*Unlock the memory pages associated with the MDL*/
			MmUnlockPages(*it);
		    /*Free The MDL */
           IoFreeMdl(*it); 
		}
	}
}
CcMdlWriteComplete2(IN PFILE_OBJECT FileObject,
                    IN PLARGE_INTEGER FileOffset,
                    IN PMDL MdlChain)
{

PLARGE_INTEGER FOffset = nullptr;
KIRQL CurrentIrql = NULL;
NTSTATUS Exception = NULL;
PIO_STATUS_BLOCK IoStatus = nullptr;


for( auto it = begin(MdlChain); it != end(MdlChain);++it)
{

    if (!(MdlChain->MdlFlags & 2) == 0) )
    {
      MmUnlockPages(*it);
     
    }
    if ( (FileObject->Flags & 16) != 0 )
    {
      MmFlushSection((*it)->ByteCount, SharedCacheMap, &IoStatus, 1);
      if ( !NTSTATUS(IoStatus.Status) )
        Exception = IoStatus.Status;
    }
    else
    {
      CcSetDirtyInMask(SharedCacheMap, &FOffset, (*it)->ByteCount);
    }
    FOffset.QuadPart += (*it)->ByteCount;
}
  
  if (!(MdlChain->MdlFlags & 2) == 0))
  {
    CurrentIrql = KeAcquireQueuedSpinLock(LockQueueMasterLock);
    CcDecrementOpenCount(SharedCacheMap);
    KeReleaseQueuedSpinLock(LockQueueMasterLock,CurrentIrql);
  }
  if (!NT_SUCCESS(Exception))                          
  {
    RtlRaiseStatus(FsRtlNormalizeNtstatus(Exception, WRITE_EXCEPTION));
  }
  /* Write Operation is COmplete, Now Free the MDL Chain*/
for( auto it = begin(MdlChain); it != end(MdlChain);++it)
  {    
		    /*Free The MDL */
           IoFreeMdl(*it); 
  }
}

/* External Function */ 
VOID
NTAPI
CcMdlRead (
    IN PFILE_OBJECT FileObject,
    IN PLARGE_INTEGER FileOffset,
    IN ULONG Length,
    OUT PMDL * MdlChain,
    OUT PIO_STATUS_BLOCK IoStatus)
{
		
	ULONG LENGTH_FINAL = Length;
	PVOID VirtualAddress = nullptr;
	PVACB VACB  = nullptr;
	ULONG ReceivedLength = NULL;
	ULONG Information = NULL;
	PMDL Allocated = NULL;
	LARGE_INTEGER FOffset = FileOffset;
	PSHARED_CACHE_MAP sharedcachmap = FileObject->SectionObjectPointer->SharedCacheMap; 
	PRIVATE_CACHE_MAP PrivateCacheMap = FileObject->PrivateCacheMap;
	PVOID VirtualAddress = nullptr;
	LARGE_INTEGER Offset_Lenghth = NULL;


_try
{

/* Iterate until it is final length is null*/ 	
	while(Length != NULL)
	{
		
		VirtualAddress = static_cast<void*>(CcGetVirtualAddress(sharedcachmap, &VACB, FOffset,(LARGE_INTEGER)&ReceivedLength, 0));
		INT PagePriority = static_cast<int>(((&sharedcachmap->NodeTypeCode >> 18) & 7));
		
		if ((sharedcachmap->Flags & 8)== null )
		{
			/* Our Memory Manager doesn't support prefetching yet, will be added in 2025*/
		//CcFetchDataForRead(FileObject,&FOffset,Length,Wait_Type_MDL_Read,&FaultedData,&VACB,PagePriority,MDL_READTYPE_DiskIoAttribution); // Return
		}
		
		if ( ReceivedLength > Length )
		{   
			ReceivedLength = Length;
		}
	
	  
	  Offset_Lenghth =  FOffset.QuadPart +  static_cast<LONGLONG>(ReceivedLength);
		
	
		/* Allocate the MDL ,it is not associated with Specific IRP*/
		Allocated = IoAllocateMdl(VirtualAddress,ReceivedLength , false, false, optional_irp);
		
		/* Assign the MDL to MmProbeAndLockPages to prevent Page Fault/ Data Corruption */
		MmProbeAndLockPages(Allocated, KernelMode, IoReadAccess);
		/* Free the VACB */
		CcFreeVirtualAddress(VACB);
		
		/* Now Update the MDL Chain with allocated one */

/* Check if Valid MDL Chain already exist, if so update it with allocated one else assign MDL Chain with one we allocated  */
   if ( *MdlChain != NULL)
    {   for( auto it = begin(MdlChain); it != end(MdlChain);++it)
		{
			*it = Allocated;
		}
    }
	else
    {
      *MdlChain = Allocated;
    }
		
	
	
	FOffset.QuadPart = Offset_Lenghth.QuadPart;
	
	/* Update the IOSTATUS Information FLag */
	Information += ReceivedLength;
	/* Adjust the length , else you will be in mess of a infinite nonsensical loop fighting with Exception Handler */ 
	Length -= ReceivedLength;
}
	
}

_finally{
	
 if ( (FileObject->Flags & 0x100000) = = 0 ||(&PrivateCacheMap->NodeType_UlongFlags & 0x20000 == 0) && FaultedData )
 {
    CcScheduleReadAheadEx(FileObject, FileOffset,Length,NULL);
	 _InterlockedOr(&PrivateCacheMap->NodeType_UlongFlags, FLAG_UPDATE_READAHEAD);
   
 }

  
/* No mater What , Catch History must be updated even if Aliens Invasion Happens that day*/
/* UPDATE CATCH HISTORY */
InterlockedExchange64(&PrivateCachemap->FileOffset1,PrivateCachemap->FileOffset2);
InterlockedExchange64(&PrivateCachemap->BeyondLastByte1,PrivateCachemap->BeyondLastByte2);
InterlockedExchange64(&PrivateCachemap->FileOffset2,*FileOffset);
LONG LONG FinalLength =FileOffset->QuadPart+ static_cast<LONGLONG>(Length);
InterlockedExchange64(&PrivateCachemap->BeyondLastByte2.Quadpart,FinalLength);

/* Update Shared Cachemap Flags */
if ( (SharedCacheMap->Flags & 8) != 0 )
{
	 KIRQL LAST_IRQL = KeAcquireQueuedSpinLock(LockQueueMasterLock);
    SharedCacheMap->Flags &= ~8;
    KeReleaseQueuedSpinLock(LockQueueMasterLock, LAST_IRQL);
}

/* Update IRP Bytes */ 
IoStatus->Status = Status_Sucess;
IoStatus->Information = Information;
}
}

VOID
NTAPI
CcMdlReadComplete(IN PFILE_OBJECT FileObject,
                  IN PMDL MdlChain)
{
    PDEVICE_OBJECT RelatedDeviceObject = IoGetRelatedDeviceObject(FileObject);
    FAST_IO_DISPATCH FastIoDispatch = RelatedDeviceObject->DriverObject->FastIoDispatch;
	/* Start Faster MDL Operator if Suceeds , don't execute slower CcMdlReadComplete2*/
	BOOL MdlReadComplete_FLag =  (*PFAST_IO_MDL_READ_COMPLETE) (  FileObject, MdlChain, RelatedDeviceObject);
    
	if ( !FastIoDispatch|| FastIoDispatch->SizeOfFastIoDispatch <= MAXIO_DISPATCH|| (MdlReadComplete_FLag = FastIoDispatch->MdlReadComplete) == 0|| !MdlReadComplete_FLag )
   {
    CcMdlReadComplete2(NULL,MdlChain);
   }
}

VOID
NTAPI
CcMdlWriteAbort(IN PFILE_OBJECT FileObject,
                IN PMDL MdlChain)
{
	
	
	
	KIRQL CurrentIrql = null;
  PSHARED_CACHE_MAP SharedCacheMap = FileObject->SectionObjectPointer->SharedCacheMap;


for( auto it = begin(MdlChain); it != end(MdlChain);++it)
{
    if ((MdlChain->MdlFlags & 2) != 0 )
   {
     MmUnlockPages(*it);
   }
   
    IoFreeMdl(*it);
    
}

  if ( (MdlChain->MdlFlags & 2) != 0 )
  {
     CurrentIrql = KeAcquireQueuedSpinLock(LockQueueMasterLock);
    CcDecrementOpenCount(SharedCacheMap);
    KeReleaseQueuedSpinLock(LockQueueMasterLock, CurrentIrql);
  }
}

VOID
NTAPI
CcMdlWriteComplete(IN PFILE_OBJECT FileObject,
                   IN PLARGE_INTEGER FileOffset,
                   IN PMDL MdlChain)
{
	
	DEVICE_OBJECT RelatedDeviceObject = IoGetRelatedDeviceObject(FileObject);
    FAST_IO_DISPATCH FastIoDispatch = RelatedDeviceObject->DriverObject->FastIoDispatch;
	
	BOOL MdlWriteComplete_FLag = (*PFAST_IO_MDL_WRITE_COMPLETE) ( FileObject, FileOffset, MdlChain, RelatedDeviceObject);
		/* Start Faster MDL Operator if Suceeds , don't execute slower CcMdlReadComplete2*/
		
		
	if (!FastIoDispatch|| FastIoDispatch->SizeOfFastIoDispatch <= MAXIO_DISPATCH|| (MdlWriteComplete_FLag = FastIoDispatch->MdlWriteComplete) == 0||  !MdlWriteComplete_FLag)
  {
     CcMdlWriteComplete2(FileObject,FileOffset,MdlChain);
  }
}