public static unsafe void WritePEChecksum(string filePath, uint checkSum)
{
using (var accessor = new StreamAccessor(new FileStream(filePath, FileMode.Open, FileAccess.ReadWrite)))
{
// DOS
DOSHeader dosHeader;
fixed(byte *pBuff = accessor.ReadBytes(PEConstants.DosHeaderSize))
{
dosHeader = *(DOSHeader *)pBuff;
}
if (dosHeader.Signature != PEConstants.DosSignature)
{
throw new BadImageFormatException(SR.DOSHeaderSignatureNotValid);
}
accessor.Position = dosHeader.Lfanew;
// NT Signature
if (accessor.ReadUInt32() != PEConstants.NTSignature)
{
throw new BadImageFormatException(SR.PESignatureNotValid);
}
// COFF
accessor.ReadBytes(PEConstants.COFFHeaderSize);
// PE
ushort peMagic = accessor.ReadUInt16();
if (peMagic == PEConstants.PEMagic32)
{
accessor.ReadBytes(62);
}
else if (peMagic == 0x20b)
{
accessor.ReadBytes(62);
}
else
{
throw new BadImageFormatException(SR.PEHeaderSignatureNotValid);
}
accessor.Write((uint)checkSum);
}
}
private void ReadExtHeader(StreamAccessor accessor, out uint crc32, out int padding)
{
uint num = accessor.ReadUInt32(EncodingType.U4BE);
if ((num != 6) && (num != 10))
{
throw new FileFormatException("Extended Header Size は 6B 亦は 10B で在るべきです。");
}
ushort num2 = accessor.ReadUInt16(EncodingType.I2BE);
this.hascrc = (num2 & 0x8000) != 0;
if (num != (this.hascrc ? ((long)10) : ((long)6)))
{
throw new FileFormatException(string.Format("Extended Header Size の大きさが不正です。\r\nCRC Checkを{0}場合には{1}B であるべきです。", this.hascrc ? "行う" : "行わない", this.hascrc ? "10" : "6"));
}
padding = accessor.ReadInt32(EncodingType.U4BE);
crc32 = this.hascrc ? accessor.ReadUInt32(EncodingType.U4BE) : 0;
}
