private void _buildAsmArrays()
{
if (OriginalLocalCode == null)
{
OriginalLocalCode = RBytes(OriginalLocalCodeStartOffset.ToInt64(), OriginalLocalCodeLength);
}
using (var _customRemoteCodeMemoryStream = new MemoryStream(OriginalLocalCodeLength))
{
//Start building wrapped user code at the location immediately after the copy of the original
//code ends (unless OriginalCodeAtEnd is defined, in which case, it's at the beginning of CustomRemoteCodeHandle) :
var customRemoteCodeCodeBuilder = new X86Writer(_customRemoteCodeMemoryStream, (IntPtr)(CustomRemoteCodeHandle.GetHandle().ToInt64()));
//If OriginalCodeAtEnd is not defined, write the original code at the start of the custom remote code:
if (!OriginalCodeAtEnd)
{
_customRemoteCodeMemoryStream.Write(OriginalLocalCode, 0, OriginalLocalCodeLength);
}
BuildCustomRemoteCode(customRemoteCodeCodeBuilder, _customRemoteCodeMemoryStream);
//If OriginalCodeAtEnd is defined, write the original code at the end of the custom remote code:
if (OriginalCodeAtEnd)
{
_customRemoteCodeMemoryStream.Write(OriginalLocalCode, 0, OriginalLocalCodeLength);
}
//Jump to return offset at end of wrapped function:
customRemoteCodeCodeBuilder.Jmp(CustomRemoteCodeReturnDestinationOffset);
//Copy the bytes of the ASM to our array before exiting the "using" statement and disposing the MemoryStream:
CustomRemoteCode = _customRemoteCodeMemoryStream.ToArray();
}
using (var _customLocalCodeMemoryStream = new MemoryStream(OriginalLocalCodeLength))
{
var customLocalCodeCodeBuilder = new X86Writer(_customLocalCodeMemoryStream, OriginalLocalCodeStartOffset);
// Jump to our wrapped code instead of doing the original code:
customLocalCodeCodeBuilder.Jmp(CustomRemoteCodeHandle.GetHandle());
// Fill in the rest of the original instructions with NOP's:
while (_customLocalCodeMemoryStream.Position < OriginalLocalCodeLength)
{
customLocalCodeCodeBuilder.Nop();
}
CustomLocalCode = _customLocalCodeMemoryStream.ToArray();
}
}
public void PatchCode(bool force = false)
{
if (IsPatched && !force)
{
return;
}
//Write the wrapped code to the allocated memory region:
var wrappedCodeHandle = CustomRemoteCodeHandle.GetHandle();
WBytes((wrappedCodeHandle, wrappedCodeHandle), CustomRemoteCode);
//Flush instruction cache for wrapped code:
Kernel.FlushInstructionCache(DARKSOULS.GetHandle(), CustomRemoteCodeHandle.GetHandle(), (UIntPtr)CustomLocalCodeAllocSize);
/*
*
* >> The rest of this method: <<
*
* Patch original local code while Dark Souls is suspended so that there will be a 0.0% chance of the
* game trying to execute only-partially-overridden code instead of the usual 0.00000001% chance ;)
*
*/
//Suspend execution of Dark Souls process:
DARKSOULS.Suspend();
//Overwrite the original local code with the custom local code:
WBytes((OriginalLocalCodeStartOffset, OriginalLocalCodeStartOffset), CustomLocalCode);
//Flush the instruction cache over the span of the local code:
Kernel.FlushInstructionCache(DARKSOULS.GetHandle(), OriginalLocalCodeStartOffset, (UIntPtr)OriginalLocalCodeLength);
//Resume execution of Dark Souls process:
DARKSOULS.Resume();
IsPatched = true;
}