From 62ebdde712d17f619e69eaf73fd97fceedc84676 Mon Sep 17 00:00:00 2001
From: Dibyamartanda Samanta <dibyaxp@noreply.codingworkshop.git>
Date: Wed, 7 Aug 2024 16:09:29 +0200
Subject: [PATCH] [NTOSKRNL:CC]  Cache Controller Pinsupport :: CcPinRead and
 CcPinMappedData

Completely implemented CcPinRead and CcPinMappedData

In future Refactor with BCB Iterator with bounds checking.
---
 NTOSKRNL/CC/ccpinsupport.cpp | 135 ++++++++++++++++++++++++++++++++++-
 1 file changed, 133 insertions(+), 2 deletions(-)

diff --git a/NTOSKRNL/CC/ccpinsupport.cpp b/NTOSKRNL/CC/ccpinsupport.cpp
index da6aea3..898edd5 100644
--- a/NTOSKRNL/CC/ccpinsupport.cpp
+++ b/NTOSKRNL/CC/ccpinsupport.cpp
@@ -727,7 +727,77 @@ CcPinMappedData(
     IN ULONG Flags,
     IN OUT PCC_BCB Bcb)
 {
-    //Unimplemented
+    PSHARED_CACHE_MAP SharedCacheMap = nullptr;
+    LARGE_INTEGER LocalFileOffset = {0};
+    LARGE_INTEGER BeyondLastByte ={0};
+    PVOID Buffer = nullptr;
+    POBCB localbcb = nullptr;
+    PCC_BCB *localbcbptr = nullptr;
+    PCC_BCB *Bcbs = nullptr;
+    bool Result = false;
+
+
+    LocalFileOffset = *FileOffset;
+
+   if (!(reinterpret_cast<PULONG>(Bcb) & 1))
+    return true;
+
+    *Bcb = reinterpret_cast<PVOID>(reinterpret_cast<ULONG_PTR>(*Bcb) - 1);
+
+    SharedCacheMap = reinterpret_cast<PSHARED_CACHE_MAP>(FileObject->SectionObjectPointer->SharedCacheMap);
+    InterlockedIncrement(&SharedCacheMap->PinCount);
+
+     if (ExAcquireSharedStarveExclusive(&((PCC_BCB)*Bcb)->BcbResource, ((Flags & 1) == 1)))
+	 {
+            Result = true;
+	  }
+    else
+    {
+        LARGE_INTEGER localoffset = LocalFileOffset;
+        ULONG RemainingLength = Length;
+
+        while (true)
+        {
+            if (localbcb)
+            {
+                if (localbcbptr == reinterpret_cast<PCC_BCB*>(&localbcb))
+                {
+                    localbcb = CcAllocateObcb(FileOffset, Length, reinterpret_cast<PCC_BCB>(localbcb));
+                    Bcbs = localbcb->Bcbs;
+                    localbcbptr = localbcb->Bcbs;
+                }
+                RemainingLength += localoffset.LowPart - BeyondLastByte.LowPart;
+                localoffset = BeyondLastByte;
+                LocalFileOffset = BeyondLastByte;
+                localbcbptr = ++Bcbs;
+            }
+
+            if (!CcPinFileData(FileObject,&LocalFileOffset,RemainingLength,!(SharedCacheMap->Flags & 0x200),false,Flags,localbcbptr,&Buffer,&BeyondLastByte))
+            {
+                Result = false;
+                break;
+            }
+
+            if ((BeyondLastByte.QuadPart - localoffset.QuadPart) >= RemainingLength)
+            {
+                CcFreeVirtualAddress(reinterpret_cast<PVACB>(*Bcb));
+                *Bcb = localbcb;
+                Result = true;
+                break;
+            }
+        }
+    }
+
+    if (!Result)
+    {
+        *Bcb = reinterpret_cast<PVOID>(reinterpret_cast<ULONG_PTR>(*Bcb) + 1);
+        if (localbcb)
+        {
+            CcUnpinData(localbcb);
+        }
+    }
+
+    return Result;
 }
 
 BOOLEAN
@@ -740,7 +810,68 @@ CcPinRead(
     OUT PVOID *Bcb,
     OUT PVOID *Buffer)
 {
-    //Unimplemented
+    PSHARED_CACHE_MAP SharedCacheMap = nullptr;
+    LARGE_INTEGER LocalFileOffset ={0};
+    LARGE_INTEGER BeyondLastByte ={0};
+    PVOID LocalBuffer = nullptr;
+    POBCB localbcb = nullptr;
+    PCC_BCB *localBcbPtr = nullptr;
+    bool Result = false;
+    ULONG RemainingLength = Length;
+
+    
+
+    LocalFileOffset = *FileOffset;
+
+    if (Flags & 1) // 1 Signifies Pin is waiting 
+        CcPinReadWait++;
+    else
+        CcPinReadNoWait++;
+
+   
+    SharedCacheMap = reinterpret_cast<PSHARED_CACHE_MAP>(FileObject->SectionObjectPointer->SharedCacheMap);
+   /* Main Pinning Loop*/
+    while (true)
+    {
+        if (localbcb)
+        {
+            if (localBcbPtr == reinterpret_cast<PCC_BCB*>(&localbcb))
+            {
+                localbcb = CcAllocateObcb(FileOffset, RemainingLength, reinterpret_cast<PCC_BCB>(localbcb));
+                localBcbPtr = localbcb->Bcbs;
+                *Buffer = LocalBuffer;
+            }
+            RemainingLength += LocalFileOffset.LowPart - BeyondLastByte.LowPart;
+            LocalFileOffset = BeyondLastByte;
+            ++localBcbPtr;
+        }
+
+        if (!CcPinFileData(FileObject,&LocalFileOffset,RemainingLength,(SharedCacheMap->Flags & 0x200) == 0,false,Flags,localBcbPtr,&LocalBuffer,&BeyondLastByte))
+        {
+            Result = false;
+            break;
+        }
+
+        if (BeyondLastByte.QuadPart - LocalFileOffset.QuadPart >= RemainingLength)
+        {
+            *Bcb = localbcb;
+            if (localBcbPtr == reinterpret_cast<PCC_BCB*>(&localbcb))
+            {
+                *Buffer = LocalBuffer;
+            }
+            Result = true;
+            break;
+        }
+    }
+
+    
+
+    if (!Result && localbcb)
+    {
+        CcUnpinData(localbcb);
+    }
+
+    return Result;
 }
 
 BOOLEAN