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Some cleanup of PeSigScanner.

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This commit is contained in:
Ottermandias 2024-07-21 22:58:03 +02:00
parent 8351b74b21
commit 0db70c89b1
2 changed files with 57 additions and 65 deletions
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4
Penumbra/Interop/Hooks/ResourceLoading/PapHandler.cs
View file

@ -17,7 +17,5 @@ public sealed class PapHandler(PapRewriter.PapResourceHandlerPrototype papResour
}
public void Dispose()
{
_papRewriter.Dispose();
}
=> _papRewriter.Dispose();
}

118
Penumbra/Interop/Hooks/ResourceLoading/PeSigScanner.cs
View file

@ -5,65 +5,56 @@ using Decoder = Iced.Intel.Decoder;
namespace Penumbra.Interop.Hooks.ResourceLoading;
// A good chunk of this was blatantly stolen from Dalamud's SigScanner 'cause I could not be faffed, maybe I'll rewrite it later
public class PeSigScanner : IDisposable
// A good chunk of this was blatantly stolen from Dalamud's SigScanner 'cause Winter could not be faffed, Winter will definitely not rewrite it later
public unsafe class PeSigScanner : IDisposable
{
private MemoryMappedFile File { get; }
private readonly MemoryMappedFile _file;
private readonly MemoryMappedViewAccessor _textSection;
private readonly nint _moduleBaseAddress;
private readonly uint _textSectionVirtualAddress;
private uint TextSectionStart { get; }
private uint TextSectionSize { get; }
private IntPtr ModuleBaseAddress { get; }
private uint TextSectionVirtualAddress { get; }
private MemoryMappedViewAccessor TextSection { get; }
public PeSigScanner()
{
var mainModule = Process.GetCurrentProcess().MainModule!;
var fileName = mainModule.FileName;
ModuleBaseAddress = mainModule.BaseAddress;
var fileName = mainModule.FileName;
_moduleBaseAddress = mainModule.BaseAddress;
if (fileName == null)
{
throw new Exception("Can't get main module path, the fuck is going on?");
}
File = MemoryMappedFile.CreateFromFile(fileName, FileMode.Open, null, 0, MemoryMappedFileAccess.Read);
throw new Exception("Unable to obtain main module path. This should not happen.");
using var fileStream = File.CreateViewStream(0, 0, MemoryMappedFileAccess.Read);
_file = MemoryMappedFile.CreateFromFile(fileName, FileMode.Open, null, 0, MemoryMappedFileAccess.Read);
using var fileStream = _file.CreateViewStream(0, 0, MemoryMappedFileAccess.Read);
var pe = new PeFile(fileStream);
var textSection = pe.ImageSectionHeaders!.First(header => header.Name == ".text");
TextSectionStart = textSection.PointerToRawData;
TextSectionSize = textSection.SizeOfRawData;
TextSectionVirtualAddress = textSection.VirtualAddress;
var textSectionStart = textSection.PointerToRawData;
var textSectionSize = textSection.SizeOfRawData;
_textSectionVirtualAddress = textSection.VirtualAddress;
TextSection = File.CreateViewAccessor(TextSectionStart, TextSectionSize, MemoryMappedFileAccess.Read);
_textSection = _file.CreateViewAccessor(textSectionStart, textSectionSize, MemoryMappedFileAccess.Read);
}
private IntPtr ScanText(string signature)
private nint ScanText(string signature)
{
var scanRet = Scan(TextSection, signature);
var instrByte = Marshal.ReadByte(scanRet);
if (instrByte is 0xE8 or 0xE9)
var scanRet = Scan(_textSection, signature);
if (*(byte*)scanRet is 0xE8 or 0xE9)
scanRet = ReadJmpCallSig(scanRet);
return scanRet;
}
private static IntPtr ReadJmpCallSig(IntPtr sigLocation)
private static nint ReadJmpCallSig(nint sigLocation)
{
var jumpOffset = Marshal.ReadInt32(sigLocation, 1);
return IntPtr.Add(sigLocation, 5 + jumpOffset);
var jumpOffset = *(int*)(sigLocation + 1);
return sigLocation + 5 + jumpOffset;
}
public bool TryScanText(string signature, out IntPtr result)
public bool TryScanText(string signature, out nint result)
{
try
{
@ -72,21 +63,22 @@ public class PeSigScanner : IDisposable
}
catch (KeyNotFoundException)
{
result = IntPtr.Zero;
result = nint.Zero;
return false;
}
}
private IntPtr Scan(MemoryMappedViewAccessor section, string signature)
private nint Scan(MemoryMappedViewAccessor section, string signature)
{
var (needle, mask) = ParseSignature(signature);
var index = IndexOf(section, needle, mask);
var index = IndexOf(section, needle, mask);
if (index < 0)
throw new KeyNotFoundException($"Can't find a signature of {signature}");
return new IntPtr(ModuleBaseAddress + index - section.PointerOffset + TextSectionVirtualAddress);
return (nint)(_moduleBaseAddress + index - section.PointerOffset + _textSectionVirtualAddress);
}
private static (byte[] Needle, bool[] Mask) ParseSignature(string signature)
{
signature = signature.Replace(" ", string.Empty);
@ -99,7 +91,7 @@ public class PeSigScanner : IDisposable
for (var i = 0; i < needleLength; i++)
{
var hexString = signature.Substring(i * 2, 2);
if (hexString == "??" || hexString == "**")
if (hexString is "??" or "**")
{
needle[i] = 0;
mask[i] = true;
@ -112,10 +104,12 @@ public class PeSigScanner : IDisposable
return (needle, mask);
}
private static unsafe int IndexOf(MemoryMappedViewAccessor section, byte[] needle, bool[] mask)
private static int IndexOf(MemoryMappedViewAccessor section, byte[] needle, bool[] mask)
{
if (needle.Length > section.Capacity) return -1;
if (needle.Length > section.Capacity)
return -1;
var badShift = BuildBadCharTable(needle, mask);
var last = needle.Length - 1;
var offset = 0;
@ -144,19 +138,19 @@ public class PeSigScanner : IDisposable
return -1;
}
private static int[] BuildBadCharTable(byte[] needle, bool[] mask)
{
int idx;
var last = needle.Length - 1;
var badShift = new int[256];
for (idx = last; idx > 0 && !mask[idx]; --idx)
{
}
{ }
var diff = last - idx;
if (diff == 0) diff = 1;
var diff = last - idx;
if (diff == 0)
diff = 1;
for (idx = 0; idx <= 255; ++idx)
badShift[idx] = diff;
@ -164,16 +158,16 @@ public class PeSigScanner : IDisposable
badShift[needle[idx]] = last - idx;
return badShift;
}
// Detects function termination; this is done in a really stupid way that will possibly break if looked at wrong, but it'll work for now
// If this shits itself, go bother Winter to implement proper CFG + basic block detection
public IEnumerable<Instruction> GetFunctionInstructions(IntPtr addr)
public IEnumerable<Instruction> GetFunctionInstructions(nint address)
{
var fileOffset = addr - TextSectionVirtualAddress - ModuleBaseAddress;
var codeReader = new MappedCodeReader(TextSection, fileOffset);
var decoder = Decoder.Create(64, codeReader, (ulong)addr.ToInt64());
var fileOffset = address - _textSectionVirtualAddress - _moduleBaseAddress;
var codeReader = new MappedCodeReader(_textSection, fileOffset);
var decoder = Decoder.Create(64, codeReader, (ulong)address.ToInt64());
do
{
decoder.Decode(out var instr);
@ -188,7 +182,7 @@ public class PeSigScanner : IDisposable
public void Dispose()
{
TextSection.Dispose();
File.Dispose();
_textSection.Dispose();
_file.Dispose();
}
}