Merge pull request #23 from AnimatedSwine37/file-size-bug

Fix original file being read when it is bigger than the emulated version

Emulator/PAK.Stream.Emulator/ModConfig.json

@@ -2,7 +2,7 @@
   "ModId": "reloaded.universal.fileemulationframework.pak",
   "ModName": "PAK Emulator for File Emulation Framework",
   "ModAuthor": "ltsophia & friends",
-  "ModVersion": "1.1.0",
+  "ModVersion": "1.1.1",
   "ModDescription": "Simulates Atlus PAK files. Allows mods to add or replace existing files using files on disk.",
   "ModDll": "PAK.Stream.Emulator.dll",
   "ModIcon": "Preview.png",

Emulator/PAK.Stream.Emulator/Pak/PakBuilder.cs

@@ -140,13 +140,8 @@ private unsafe MultiStream BuildV1(IEntry[] entries, IntPtr handle, string filep
                 pairs.Add(new(new FileSliceStreamW32(overwrittenFile, logger), OffsetRange.FromStartAndLength(currentOffset + sizeofentry, overwrittenFile.Length)));
                 if (length > overwrittenFile.Length)
                 {
-                    var overstream = new MemoryStream();
                     byte[] buffer = new byte[length - overwrittenFile.Length];
-                    for (int f = 0; i < buffer.Length; i++)
-                    {
-                        buffer[f] = 0x00;
-                    }
-                    overstream.Write(buffer, 0, buffer.Length);
+                    var overstream = new MemoryStream(buffer);
                     pairs.Add(new(overstream, OffsetRange.FromStartAndLength(currentOffset + sizeofentry + overwrittenFile.Length, buffer.Length)));
                 }
             }
@@ -179,10 +174,6 @@ private unsafe MultiStream BuildV1(IEntry[] entries, IntPtr handle, string filep
                     {
                         entryStream.Seek((int)entryStream.Length, SeekOrigin.Begin);
                         byte[] buffer = new byte[length - (int)entryStream.Length];
-                        for (int f = 0; i < buffer.Length; i++)
-                        {
-                            buffer[f] = 0x00;
-                        }
                         entryStream.Write(buffer, 0, buffer.Length);
                     }
                     pairs.Add(new(entryStream, OffsetRange.FromStartAndLength(currentOffset + sizeofentry, length)));
@@ -212,6 +203,12 @@ private unsafe MultiStream BuildV1(IEntry[] entries, IntPtr handle, string filep
         // Merge the slices and add.
         foreach (var merged in FileSliceStreamExtensions.MergeStreams(mergeAbleStreams))
             pairs.Add(merged);
+
+        // Add an extra empty entry header (the game might try to read it)
+        byte[] dummyBuffer = new byte[sizeof(V1FileEntry)];
+        MemoryStream dummyHeader = new MemoryStream(dummyBuffer);
+        pairs.Add(new(dummyHeader, OffsetRange.FromStartAndLength(currentOffset, sizeof(V1FileEntry))));
+
         // Return MultiStream
         return new MultiStream(pairs, logger);
     }
@@ -294,13 +291,8 @@ private unsafe MultiStream BuildV2(IEntry[] entries, IntPtr handle, string filep
                 pairs.Add(new(new FileSliceStreamW32(overwrittenFile, logger), OffsetRange.FromStartAndLength(currentOffset + sizeofentry, overwrittenFile.Length)));
                 if (length > overwrittenFile.Length)
                 {
-                    var overstream = new MemoryStream();
                     byte[] buffer = new byte[length - overwrittenFile.Length];
-                    for (int f = 0; i < buffer.Length; i++)
-                    {
-                        buffer[f] = 0x00;
-                    }
-                    overstream.Write(buffer, 0, buffer.Length);
+                    var overstream = new MemoryStream(buffer);
                     pairs.Add(new(overstream, OffsetRange.FromStartAndLength(currentOffset + sizeofentry + overwrittenFile.Length, buffer.Length)));
                 }
             }
@@ -334,10 +326,6 @@ private unsafe MultiStream BuildV2(IEntry[] entries, IntPtr handle, string filep
                     {
                         entryStream.Seek((int)entryStream.Length, SeekOrigin.Begin);
                         byte[] buffer = new byte[length - (int)entryStream.Length];
-                        for (int f = 0; i < buffer.Length; i++)
-                        {
-                            buffer[f] = 0x00;
-                        }
                         entryStream.Write(buffer, 0, buffer.Length);
                     }
                     pairs.Add(new(entryStream, OffsetRange.FromStartAndLength(currentOffset + sizeofentry, length)));
@@ -368,6 +356,13 @@ private unsafe MultiStream BuildV2(IEntry[] entries, IntPtr handle, string filep
         // Merge the slices and add.
         foreach (var merged in FileSliceStreamExtensions.MergeStreams(mergeAbleStreams))
             pairs.Add(merged);
+
+        // Add an extra empty entry header (the game might try to read it)
+        byte[] dummyBuffer = new byte[sizeof(V2FileEntry)];
+        MemoryStream dummyHeader = new MemoryStream(dummyBuffer);
+        dummyHeader.Write(dummyBuffer, 0, dummyBuffer.Length);
+        pairs.Add(new(dummyHeader, OffsetRange.FromStartAndLength(currentOffset, sizeof(V2FileEntry))));
+
         // Return MultiStream
         return new MultiStream(pairs, logger);
     }
@@ -450,13 +445,8 @@ private unsafe MultiStream BuildV3(IEntry[] entries, IntPtr handle, string filep
                 pairs.Add(new(new FileSliceStreamW32(overwrittenFile, logger), OffsetRange.FromStartAndLength(currentOffset + sizeofentry, overwrittenFile.Length)));
                 if (length > overwrittenFile.Length)
                 {
-                    var overstream = new MemoryStream();
                     byte[] buffer = new byte[length - overwrittenFile.Length];
-                    for (int f = 0; i < buffer.Length; i++)
-                    {
-                        buffer[f] = 0x00;
-                    }
-                    overstream.Write(buffer, 0, buffer.Length);
+                    var overstream = new MemoryStream(buffer);
                     pairs.Add(new(overstream, OffsetRange.FromStartAndLength(currentOffset + sizeofentry + overwrittenFile.Length, buffer.Length)));
                 }
             }
@@ -489,10 +479,6 @@ private unsafe MultiStream BuildV3(IEntry[] entries, IntPtr handle, string filep
                     {
                         entryStream.Seek((int)entryStream.Length, SeekOrigin.Begin);
                         byte[] buffer = new byte[length - (int)entryStream.Length];
-                        for (int f = 0; i < buffer.Length; i++)
-                        {
-                            buffer[f] = 0x00;
-                        }
                         entryStream.Write(buffer, 0, buffer.Length);
                     }
                     pairs.Add(new(entryStream, OffsetRange.FromStartAndLength(currentOffset + sizeofentry, length)));
@@ -520,6 +506,13 @@ private unsafe MultiStream BuildV3(IEntry[] entries, IntPtr handle, string filep
         // Merge the slices and add.
         foreach (var merged in FileSliceStreamExtensions.MergeStreams(mergeAbleStreams))
             pairs.Add(merged);
+
+        // Add an extra empty entry header (the game might try to read it)
+        byte[] dummyBuffer = new byte[sizeof(V3FileEntry)];
+        MemoryStream dummyHeader = new MemoryStream(dummyBuffer);
+        dummyHeader.Write(dummyBuffer, 0, dummyBuffer.Length);
+        pairs.Add(new(dummyHeader, OffsetRange.FromStartAndLength(currentOffset, sizeof(V3FileEntry))));
+
         // Return MultiStream
         return new MultiStream(pairs, logger);
     }

FileEmulationFramework.Interfaces/IEmulatedFile.cs

@@ -22,7 +22,7 @@ public interface IEmulatedFile
     /// <param name="offset">Offset of the data to be received.</param>
     /// <param name="info">Additional information about the current file being processed.</param>
     /// <param name="numReadBytes">Number of bytes read by the function call.</param>
-    /// <returns>True if the operation succeeded, else false. Return true if at least 1 byte was read.</returns>
+    /// <returns>True if at least one byte was read, false otherwise (this indicates the EOF has been reached).</returns>
     public unsafe bool ReadData(IntPtr handle, byte* buffer, uint length, long offset, IFileInformation info, out int numReadBytes);
 
     /// <summary>

FileEmulationFramework/FileAccessServer.cs

@@ -103,7 +103,7 @@ private static void DequeueHandles()
     }
 
     [UnmanagedCallersOnly(CallConvs = new[] { typeof(CallConvStdcall) })]
-    private static int QueryInformationFileImpl(IntPtr hfile, IO_STATUS_BLOCK* ioStatusBlock, byte* fileInformation, uint length, FileInformationClass fileInformationClass)
+    private static NT_STATUS QueryInformationFileImpl(IntPtr hfile, IO_STATUS_BLOCK* ioStatusBlock, byte* fileInformation, uint length, FileInformationClass fileInformationClass)
     {
         var result = _getFileSizeHook.OriginalFunction.Value.Invoke(hfile, ioStatusBlock, fileInformation, length, fileInformationClass);
         if (fileInformationClass != FileInformationClass.FileStandardInformation || !HandleToInfoMap.TryGetValue(hfile, out var info))
@@ -139,12 +139,12 @@ private static int QueryAttributesFileImpl(OBJECT_ATTRIBUTES* attributes, FILE_N
     }
 
     [UnmanagedCallersOnly(CallConvs = new[] { typeof(CallConvStdcall) })]
-    private static int SetInformationFileHook(IntPtr hfile, IO_STATUS_BLOCK* ioStatusBlock, byte* fileInformation, uint length, FileInformationClass fileInformationClass)
+    private static NT_STATUS SetInformationFileHook(IntPtr hfile, IO_STATUS_BLOCK* ioStatusBlock, byte* fileInformation, uint length, FileInformationClass fileInformationClass)
     {
         return SetInformationFileImpl(hfile, ioStatusBlock, fileInformation, length, fileInformationClass);
     }
 
-    private static int SetInformationFileImpl(IntPtr hfile, IO_STATUS_BLOCK* ioStatusBlock, byte* fileInformation, uint length, FileInformationClass fileInformationClass)
+    private static NT_STATUS SetInformationFileImpl(IntPtr hfile, IO_STATUS_BLOCK* ioStatusBlock, byte* fileInformation, uint length, FileInformationClass fileInformationClass)
     {
         if (fileInformationClass != FileInformationClass.FilePositionInformation || !HandleToInfoMap.TryGetValue(hfile, out var info))
             return _setFilePointerHook.OriginalFunction.Value.Invoke(hfile, ioStatusBlock, fileInformation, length, fileInformationClass);
@@ -159,7 +159,7 @@ private static int SetInformationFileImpl(IntPtr hfile, IO_STATUS_BLOCK* ioStatu
     }
 
     [UnmanagedCallersOnly(CallConvs = new[] { typeof(CallConvStdcall) })]
-    private static int NtReadFileImpl(IntPtr handle, IntPtr hEvent, IntPtr* apcRoutine, IntPtr* apcContext,
+    private static NT_STATUS NtReadFileImpl(IntPtr handle, IntPtr hEvent, IntPtr* apcRoutine, IntPtr* apcContext,
         IO_STATUS_BLOCK* ioStatus, byte* buffer, uint length, long* byteOffset, IntPtr key)
     {
         // Check if this is one of our files.
@@ -184,18 +184,24 @@ private static int NtReadFileImpl(IntPtr handle, IntPtr hEvent, IntPtr* apcRouti
             requestedOffset += numReadBytes;
             SetInformationFileImpl(handle, ioStatus, (byte*)&requestedOffset, sizeof(long), FileInformationClass.FilePositionInformation);
 
-            // Set number of read bytes.
-            ioStatus->Status = 0;
+            // Set status
+            ioStatus->Status = NT_STATUS.STATUS_SUCCESS;
             ioStatus->Information = new(numReadBytes);
-            return 0;
+            return NT_STATUS.STATUS_SUCCESS;
+        }
+        else
+        {
+            _logger.Debug("[FileAccessServer] Likely EOF, Length: {0}, Offset: {1}", numReadBytes, requestedOffset);
+
+            // Set status (note that we're assuming that if File.ReadData fails then we're at the end of the file)
+            ioStatus->Status = NT_STATUS.STATUS_END_OF_FILE;
+            ioStatus->Information = new(numReadBytes);
+            return NT_STATUS.STATUS_END_OF_FILE;
         }
-
-        return _readFileHook.OriginalFunction.Value.Invoke(handle, hEvent, apcRoutine, apcContext, ioStatus, buffer,
-            length, byteOffset, key);
     }
 
     [UnmanagedCallersOnly(CallConvs = new[] { typeof(CallConvStdcall) })]
-    private static int NtCreateFileImpl(IntPtr* handle, FileAccess access, OBJECT_ATTRIBUTES* objectAttributes, IO_STATUS_BLOCK* ioStatus, long* allocSize, uint fileAttributes, FileShare share, uint createDisposition, uint createOptions, IntPtr eaBuffer, uint eaLength)
+    private static NT_STATUS NtCreateFileImpl(IntPtr* handle, FileAccess access, OBJECT_ATTRIBUTES* objectAttributes, IO_STATUS_BLOCK* ioStatus, long* allocSize, uint fileAttributes, FileShare share, uint createDisposition, uint createOptions, IntPtr eaBuffer, uint eaLength)
     {
         lock (ThreadLock)
         {

FileEmulationFramework/Utilities/Native.cs

@@ -16,7 +16,7 @@ public struct CloseHandleFn
     {
         public FuncPtr<
             IntPtr, // handle 
-            int // status
+            NT_STATUS // status
         > Value;
     }
 
@@ -36,7 +36,7 @@ public FuncPtr<
             uint, // createOptions
             IntPtr, // eaBuffer
             uint, // eaLength
-            int // status
+            NT_STATUS // status
         > Value;
     }
 
@@ -54,7 +54,7 @@ public FuncPtr<
             uint, // length
             Ptr<long>, // byteOffset
             IntPtr, // key
-            int // status
+            NT_STATUS // status
         > Value;
     }
 
@@ -68,7 +68,7 @@ public FuncPtr<
             Ptr<byte>,   // fileInformation
             uint, // length
             FileInformationClass, // fileInformationClass
-            int // status
+            NT_STATUS // status
         > Value;
     }
 
@@ -82,7 +82,7 @@ public FuncPtr<
             Ptr<byte>,   // fileInformation
             uint, // length
             FileInformationClass, // fileInformationClass
-            int // status
+            NT_STATUS // status
         > Value;
     }
 
@@ -104,7 +104,7 @@ public FuncPtr<
     [StructLayout(LayoutKind.Sequential)]
     public struct IO_STATUS_BLOCK
     {
-        public UInt32 Status;
+        public NT_STATUS Status;
         public IntPtr Information;
     }
 
@@ -197,4 +197,17 @@ public enum FileInformationClass
         FileMaximumInformation,
 #pragma warning restore CS1591
     }
+
+    /// <summary>
+    /// An enumeration of Status values returned by functions.
+    /// There are a lot so only including ones that we actually need to use.
+    /// </summary>
+    public enum NT_STATUS : uint
+    {
+        #pragma warning disable CS1591
+        STATUS_SUCCESS = 0,
+        STATUS_END_OF_FILE = 0xC0000011,
+#pragma warning restore CS1591
+    }
+
 }