/* PROJECT: Alcyone  Kernel
* LICENSE: BSD Clause 3 
* PURPOSE: Cache Controller:: LOG Handler   
* NT KERNEL: 5.11.9360 
* COPYRIGHT: 2023-2029 Dibymartanda Samanta <>
*/    


#include <ntoskrnl.h>
#define NTDEBUG
#include <debug.h>
#include "ccinternal.hpp"
#include "ccloghandler.hpp"

extern "C"

LARGE_INTEGER
NTAPI
CcGetDirtyPages(IN PVOID LogHandle,
                IN PDIRTY_PAGE_ROUTINE DirtyPageRoutine,
                IN PVOID Context1,
                IN PVOID Context2)
{
   __try
{
    KIRQL OldIrql = {0};
    PSHARED_CACHE_MAP SharedCacheMap = nullptr;
    PFILE_OBJECT *FileObject = nullptr;
    PCC_BCB  Bcb = nullptr, 
	PCC_BCB  BcbToUnpin = nullptr;
    PLIST_ENTRY Entry = &CcDirtyLoggedStreamLinks;
    LARGE_INTEGER OldestLsn = {0};
    LARGE_INTEGER Result = {0};
    BOOLEAN FirstIteration = TRUE;

    // Acquire Master Lock
    OldIrql = KeAcquireQueuedSpinLock(LockQueueMasterLock);

    // Iterate through all Dirty Shared Cache Maps
	for (auto it = ListEntryIterator::begin(Entry); it != ListEntryIterator::end(Entry); ++it)
    {
        SharedCacheMap = CONTAINING_RECORD(*it, SHARED_CACHE_MAP, LoggedStreamLinks);

        // Check flags and validate LogHandle
        if ((SharedCacheMap->Flags & 0x800) != 0) 
		    {   
              DBGPRINT("CcGetDirtyPages::Invalid Flag \n")
		      return;
            }

        if ((SharedCacheMap->Flags & 0x2000000) != 0 && SharedCacheMap->LogHandle == LogHandle)
		    {
            SharedCacheMap->OpenCount++;
            SharedCacheMap->DirtyPages++;
            KeReleaseQueuedSpinLock(LockQueueMasterLock, OldIrql);

            /* Reference the shared cache map file object*/
            FileObject = CcReferenceSharedCacheMapFileObject(SharedCacheMap);

            /* Acquire the BCB Lock */
             oldIrql = ExAcquireSpinLockShared (&SharedCacheMap->BcbSpinLock);

            /* Iterate over BCB List */
			      for (auto it = ListEntryIterator::begin(&SharedCacheMap->BcbList); it != ListEntryIterator::end(&SharedCacheMap->BcbList); ++it)
            {
			          Bcb = CONTAINING_RECORD(*it, CC_BCB, BcbLinks);

                /* Ensure the BCB is marked as dirty */
                if (Bcb->NodeTypeCode == NODE_TYPE_DIRTY_BCB && Bcb->NodeByteCode) 
                {   LocalFileOffset = Bcb->BaseData;
                    LocalOldestLsn = Bcb->OldestLsn;
                    LocalNewestLsn = Bcb->NewestLsn;

                    /*Increment the PinCount to keep the BCB pinned*/ 
                    Bcb->PinCount++;

                    /*Release the BCB lock temporarily for the callback*/
                    ExReleaseSpinLockShared (&SharedCacheMap->BcbSpinLock,oldIrql);

                    /*Unpin any previously pinned BCB*/
                    if (BcbToUnpin) 
                    {
                        CcUnpinFileDataEx(BcbToUnpin, 1, 0);
                        BcbToUnpin = NULL;
                    }

                    /* Invoke the provided dirty page routine*/
                    DirtyPageRoutine(FileObject,
                                         &LocalFileOffset,
                                         SharedCacheMap,
                                         &LocalOldestLsn,
                                         &LocalNewestLsn,
                                         Context1,
                                         Context2);
                    if (LocalOldestLsn.QuadPart && OldestLsn.QuadPart || LocalOldestLsn.QuadPart < OldestLsn.QuadPart) 
                        {
                            OldestLsn = LocalOldestLsn;
                        }
               }

                    // Reacquire the BCB lock
                    oldIrql = ExAcquireSpinLockShared (&SharedCacheMap->BcbSpinLock);
                    // Decrement the PinCount or mark for unpinning
                    if (Bcb->PinCount > 1)
                     {
                        Bcb->PinCount--;
                        BcbToUnpin = NULL;
                    } 
                    else 
                    {
                        BcbToUnpin = Bcb;
                    }
                }
            }

            /*Release the BCB lock*/ 
            ExReleaseSpinLockShared (&SharedCacheMap->BcbSpinLock,oldIrql);
			
            /* Dereference the shared cache map file object*/
            CcDereferenceSharedCacheMapFileObject(SharedCacheMap, FileObject);

            /*Unpin any remaining BCB*/
            if (BcbToUnpin) 
			      {
                CcUnpinFileDataEx(BcbToUnpin, 1,0);
                BcbToUnpin = NULL;
            }

            OldIrql = KeAcquireQueuedSpinLock(LockQueueMasterLock);

            /*Decrement the OpenCount and DirtyPages*/ 
            SharedCacheMap->OpenCount--;
            SharedCacheMap->DirtyPages--;
		    KeReleaseQueuedSpinLock(LockQueueMasterLock,OldIrql);
        }
}

}


LARGE_INTEGER
NTAPI
CcGetLsnForFileObject(IN PFILE_OBJECT FileObject,
                      OUT OPTIONAL PLARGE_INTEGER OldestLsn)
{    
     /* IMPLEMENTATION INCOMPLETE*/
}


Void NTAPI CcSetAdditionalCacheAttributes(
  In PFILE_OBJECT FileObject,
  In BOOLEAN      DisableReadAhead,
  In BOOLEAN      DisableWriteBehind
)
{

  PSHARED_CACHE_MAP SharedCacheMap = FileObject->SectionObjectPointer->SharedCacheMap;
  KIRQL oldlock = KeAcquireQueuedSpinLock(LockQueueMasterLock);
  if ( DisableReadAhead )
    SharedCacheMap->Flags |= READAHEAD_FLAG;
  else
    SharedCacheMap->Flags &= ~READAHEAD_FLAG;
  if ( DisableWriteBehind )
    SharedCacheMap->Flags |= DISABLE_WRITE_FLAG;
  else
    SharedCacheMap->Flags &= ~ENABLE_WRITE_FLAG;
  KeReleaseQueuedSpinLock(LockQueueMasterLock, oldlock);

}
VOID NTAPI CcSetAdditionalCacheAttributesEx(PFILE_OBJECT FileObject, 
                                            ULONG Flags)
{
    PSHARED_CACHE_MAP sharedCacheMap = FileObject->SectionObjectPointer->SharedCacheMap;
    KIRQL irqlDisableWriteBehind = {0};
    KLOCK_QUEUE_HANDLE lockQueueHandle = {0};
    BOOL disableReadAhead = (Flags & 2) != 0;
    if (sharedCacheMap == nullptr||!sharedCacheMap->OpenCount)
       DBGPRINT("Invalid Shared Cache Map or Open Count")
       return;

    
    if ((sharedCacheMap->Flags & 0x2000) == 0)
        CcSetAdditionalCacheAttributes(FileObject, disableReadAhead, (Flags & 4) != 0);

    
    KeAcquireInStackQueuedSpinLockAtDpcLevel(&sharedCacheMap->BcbLock, &lockQueueHandle);

    if ((Flags & 1) != 0)
        sharedCacheMap->Flags |= FLAG_DISABLE_WRITE_BEHIND;
    else
        sharedCacheMap->Flags &= ~FLAG_DISABLE_WRITE_BEHIND;

    if ((Flags & 8) != 0)
    {
        sharedCacheMap->Flags |= FLAG_DISABLE_LAZY_WRITER;
    }
    else
    {
        if ((sharedCacheMap->Flags & FLAG_DISABLE_LAZY_WRITER) != 0)
            sharedCacheMap->Flags |= FLAG_LAZY_WRITER_ACTIVE;
        sharedCacheMap->Flags &= ~FLAG_DISABLE_LAZY_WRITER;
    }

    if ((Flags & 0x10) != 0)
        sharedCacheMap->Flags |= FLAG_DISABLE_LAZY_WRITER_SCAN;
    else
        sharedCacheMap->Flags &= ~FLAG_DISABLE_LAZY_WRITER_SCAN;

    if ((Flags & 0x20) != 0)
        sharedCacheMap->Flags |= FLAG_DISABLE_METADATA_FLUSH;
    else
        sharedCacheMap->Flags &= ~FLAG_DISABLE_METADATA_FLUSH;

    KeReleaseInStackQueuedSpinLockFromDpcLevel(&lockQueueHandle);
    
}


VOID
NTAPI
CcSetLogHandleForFile(IN PFILE_OBJECT FileObject,
                      IN PVOID LogHandle,
                      IN PFLUSH_TO_LSN FlushToLsnRoutine)
{
  PSHARED_CACHE_MAP SharedCacheMap = FileObject->SectionObjectPointer->SharedCacheMap
  SharedCacheMap->LogHandle = LogHandle;
  SharedCacheMap->FlushToLsnRoutine = FlushToLsnRoutine;
}

VOID
NTAPI
CcSetLogHandleForFileEx(
    IN PFILE_OBJECT FileObject,
    IN PVOID LogHandle,
    IN PFLUSH_TO_LSN FlushToLsnRoutine
	IN PQUERY_LOG_USAGE QueryLogUsageRoutine
   _In_opt_ PFILE_OBJECT RelatedLogHandleFileObject
)
{
    PSHARED_CACHE_MAP SharedCacheMap;
    KIRQL OldIrql;
    LOG_HANDLE_CONTEXT LogHandleContext;
    PLOG_HANDLE_CONTEXT VolumeLogHandleContext;
    LIST_ENTRY *ListHead;
    LIST_ENTRY *PrevEntry;

    // Retrieve the Shared Cache Map
    SharedCacheMap = (PSHARED_CACHE_MAP)FileObject->SectionObjectPointer->SharedCacheMap;

    // Validate Shared Cache Map
    if (!SharedCacheMap || SharedCacheMap->OpenCount == 0) 
    {
        
		return;
    }
    if (SharedCacheMap->Flags & FLAG_LOGHANDLE_SET) 
    {
        return;
    }

    OldIrql = KeAcquireQueuedSpinLock(LockQueueMasterLock);

    /* Remove the existing log handle if present*/
    if (SharedCacheMap->LogHandle) 
	{
        RemoveEntryList(&SharedCacheMap->LoggedStreamLinks);
    }

    /*Handle the case when a new log handle is not provided*/
    if (!LogHandle) 
	{
        SharedCacheMap->Flags &= ~FLAG_LOGHANDLE_NOT_SET;
        SharedCacheMap->LogHandle = NULL;
        KeReleaseQueuedSpinLock(LockQueueMasterLock, OldIrql);
        return;
    }

    /* Determine the appropriate list based on whether there are dirty pages*/
    if (SharedCacheMap->DirtyPages) 
	{
        ListHead = &CcDirtyLoggedStreamLinks;
    } 
	else 
	{
        ListHead = &CcCleanLoggedStreamLinks;
    }

    PrevEntry = ListHead->Blink;
    InsertTailList(ListHead, &SharedCacheMap->LoggedStreamLinks);
	
	  /*Initialize the volume log handle context if not already present*/
    VolumeLogHandleContext = &SharedCacheMap->VolumeCacheMap->LogHandleContext;

    if (VolumeLogHandleContext->LogHandle == NULL) 
	{
        RtlZeroMemory(&LogHandleContext, sizeof(LOG_HANDLE_CONTEXT));
        LogHandleContext.LastLWTimeStamp.QuadPart = -1;
        LogHandleContext.LogHandle = LogHandle;
        LogHandleContext.FlushToLsnRoutine = FlushToLsnRoutine;
        LogHandleContext.QueryLogUsageRoutine = QueryLogUsageRoutine;

        if (RelatedLogHandleFileObject) 
		{
            ObfReferenceObjectWithTag(RelatedLogHandleFileObject, 'tlFD');
            LogHandleContext.RelatedFileObject = RelatedLogHandleFileObject;
        }

        RtlCopyMemory(VolumeLogHandleContext, &LogHandleContext, sizeof(LOG_HANDLE_CONTEXT));
    }

   
    SharedCacheMap->LogHandle = VolumeLogHandleContext;

    /*Update the flags and dirty page statistics*/
    if (!(SharedCacheMap->Flags & FLAG_LOGHANDLE_NOT_SET)) 
	{
        if (SharedCacheMap->DirtyPages) 
		{
            VolumeLogHandleContext->DirtyPageStatistics.DirtyPages += SharedCacheMap->DirtyPages;
        }
    }

    SharedCacheMap->Flags |= FLAG_LOGHANDLE_NOT_SET;

    KeReleaseQueuedSpinLock(LockQueueMasterLock, OldIrql);
}