public unsafe void DeLocateBuff32(byte[] bytes, uint Delta, uint RVA, Reloc[] relocs)
{
// round down to page alignment
var xVA = RVA & ~4095u;
byte* basep;
if (relocs == null)
return;
fixed(byte* bp = bytes)
{
for (int i = 0; i < relocs.Length; i++)
{
if (relocs[i].PageRVA == xVA)
{
// ANY OVERHANG FROM (LAST-VA == VA-4096), use, otherwise ignore
if (OverHang != 0 && (xVA - 4096) == OverHang)
{
var _3bp = bp;
// have only written 1 byte in the previous page
switch (OvrOffset)
{
case 1:
if (CarryOne) b = (byte)(*_3bp - 1); else b = *_3bp;
CarryOne = b < ((Delta & 0x0000FF00) >> 8) ? true : false;
*_3bp = (byte)(b - ((Delta & 0xFF00) >> 8));
_3bp++;
if (CarryOne) b = (byte)(*_3bp - 1); else b = *_3bp;
CarryOne = b < ((Delta & 0x00FF0000) >> 16) ? true : false;
*_3bp = (byte)(b - ((Delta & 0x00FF0000) >> 16));
_3bp++;
if (CarryOne) b = (byte)(*_3bp - 1); else b = *_3bp;
CarryOne = b < ((Delta & 0xFF000000) >> 24) ? true : false;
*_3bp = (byte)(b - ((Delta & 0xFF000000) >> 24));
break;
case 2:
if (CarryOne) b = (byte)(*_3bp - 1); else b = *_3bp;
CarryOne = b < ((Delta & 0x00FF0000) >> 16) ? true : false;
*_3bp = (byte)(b - ((Delta & 0x00FF0000) >> 16));
_3bp++;
if (CarryOne) b = (byte)(*_3bp - 1); else b = *_3bp;
CarryOne = b < ((Delta & 0xFF000000) >> 24) ? true : false;
*_3bp = (byte)(b - ((Delta & 0xFF000000) >> 24));
break;
case 3:
if (CarryOne) b = (byte)(*_3bp - 1); else b = *_3bp;
CarryOne = b < ((Delta & 0xFF000000) >> 24) ? true : false;
*_3bp = (byte)(b - ((Delta & 0xFF000000) >> 24));
break;
default:
break;
}
// reset overhang
OverHang = 0;
CarryOne = false;
}
for (int j = 0; j < relocs[i].Area.Length; j++)
{
// their can be a trailing null entry sometimes
if (relocs[i].Area[j] == 0)
continue;
// 4KB max limit
var offset = (relocs[i].Area[j]) & 0xFFFu;
// trim offset if we are unaligned reading
if (RVA != xVA)
{
var Unaligned = RVA - xVA;
// this reloc entry is for an earlier/unaligned page
if (offset < Unaligned)
continue;
offset -= Unaligned;
}
// reset to base pointer every fixup
basep = bp;
// get byte offset
basep += offset;
// WRITE 4
if (offset < 4093)
{
// get int* to byte offset
var intp = (uint*)basep;
var curr = *intp;
// this has got to be an error
//if(curr == 0)
//Console::WriteLine("B00G");
*intp = curr - Delta;
OvrOffset = 0;
}
else {
var _3bp = basep;
OverHang = xVA;
OvrOffset = (int)(4096 - offset);
switch (offset)
{
// WRITE 3
case 4093:
{
b = *_3bp;
CarryOne = b < (Delta & 0x000000FF) ? true : false;
*_3bp = (byte)(b - (Delta & 0x000000FF));
_3bp++;
if (CarryOne) b = (byte)(*_3bp - 1); else b = *_3bp;
CarryOne = b < ((Delta & 0x0000FF00) >> 8) ? true : false;
*_3bp = (byte)(b - ((Delta & 0x0000FF00) >> 8));
_3bp++;
if (CarryOne) b = (byte)(*_3bp - 1); else b = *_3bp;
CarryOne = b < ((Delta & 0x00FF0000) >> 16) ? true : false;
*_3bp = (byte)(b - ((Delta & 0x00FF0000) >> 16));
break;
} // WRITE 2
case 4094:
{
b = *_3bp;
CarryOne = b < (Delta & 0x000000FF) ? true : false;
*_3bp = (byte)(b - (Delta & 0x000000FF));
_3bp++;
if (CarryOne) b = (byte)(*_3bp - 1); else b = *_3bp;
CarryOne = b < ((Delta & 0x0000FF00) >> 8) ? true : false;
*_3bp = (byte)(b - ((Delta & 0x0000FF00) >> 8));
_3bp++;
break;
} // WRITE 1
case 4095:
{
b = *_3bp;
CarryOne = b < (Delta & 0x000000FF) ? true : false;
*_3bp = (byte)(b - ((Delta & 0x000000FF)));
break;
}
default:
break;
}
}
}
}
}
}
}
/// <summary>
/// This routine takes a binary .reloc and emit's List of type Reloc
///
/// There are theoretically some .reloc entries we do not support, I've not seen too many for recent binaries.
///
/// If we wanted to support more, adding more translations here would be fine.
/// </summary>
/// <param name="FileBuff"></param>
/// <returns></returns>
public static List<Reloc> ProcessRelocs(byte[] FileBuff)
{
var rv = new List<Reloc>();
using (var ms = new MemoryStream(FileBuff))
using (var reReader = new BinaryReader(ms))
{
var pageRVA = reReader.ReadUInt32();
var blockSize = reReader.ReadInt32();
var BlockPos = ms.Position;
var Count = (blockSize - 8) / 2;
while (blockSize != 0)
{
var rl = new Reloc { PageRVA = pageRVA, BlockSize = blockSize, Area = new ushort[Count] };
for (int i = 0; i < Count; i++)
rl.Area[i] = reReader.ReadUInt16();
rv.Add(rl);
pageRVA = reReader.ReadUInt32();
if (pageRVA == 0)
break;
blockSize = reReader.ReadInt32();
if (blockSize == 0)
break;
Count = (blockSize - 8) / 2;
}
}
return rv;
}
