public static DOSHeader Parse(BinaryReader reader)
{
var signature = reader.ReadUInt16();
if (DOSSignature != signature)
{
throw new Exception("Invalid DOS header signature");
}
var header = new DOSHeader
{
BytesOnLastPage = reader.ReadUInt16(),
PageCount = reader.ReadUInt16(),
RelocationCount = reader.ReadUInt16(),
HeaderSize = reader.ReadUInt16(),
MinExtraParagraphs = reader.ReadUInt16(),
MaxExtraParagraphs = reader.ReadUInt16(),
InitialSS = reader.ReadUInt16(),
InitialSP = reader.ReadUInt16(),
Checksum = reader.ReadUInt16(),
InitialIP = reader.ReadUInt16(),
InitialCS = reader.ReadUInt16(),
RelocationTableOffset = reader.ReadUInt16(),
OverlayNumber = reader.ReadUInt16()
};
// reserved words
for (var i = 0; i < 4; i++)
{
reader.ReadUInt16();
}
header.OemID = reader.ReadUInt16();
header.OemInfo = reader.ReadUInt16();
// reserved words
for (var i = 0; i < 10; i++)
{
reader.ReadUInt16();
}
header.CoffHeaderOffset = reader.ReadUInt32();
return(header);
}
public void WritePortableExecutable(BinaryWriter writer)
{
writer.BaseStream.Seek(0, SeekOrigin.Begin);
DOSHeader.Write(writer);
writer.Write(_dosStubBytes);
COFFHeader.Write(writer);
PEHeaderOffset = (uint)writer.BaseStream.Position;
PEHeader.Write(writer);
for (var i = 0; i < COFFHeader.NumberOfSections; i++)
{
SectionHeaders[i].Write(writer);
}
writer.Write(_filler);
for (var i = 0; i < COFFHeader.NumberOfSections; i++)
{
writer.Write(Sections[i]);
}
writer.Write(_remainingBytes);
// Write Import Directory:
var importDirectoryEntry = PEHeader.DataDirectories[(int)DataDirectoryName.Import];
if (importDirectoryEntry.VirtualAddress > 0)
{
var importDirectoryFileOffset = GetOffsetFromRVA(importDirectoryEntry.VirtualAddress);
writer.Seek((int)importDirectoryFileOffset, SeekOrigin.Begin);
ImportDirectory.Write(writer);
}
// Update PE checksum:
writer.Seek(0, SeekOrigin.Begin);
var fileBytes = new byte[writer.BaseStream.Length];
writer.BaseStream.Read(fileBytes, 0, (int)writer.BaseStream.Length);
var checksumOffset = PEHeaderOffset + PEHeader.ChecksumRelativeAddress;
var checksum = PortableExecutableUtils.CalculcateChecksum(fileBytes, checksumOffset);
writer.Seek((int)checksumOffset, SeekOrigin.Begin);
writer.Write(checksum);
writer.Flush();
}
public void Parse(BinaryReader reader)
{
DOSHeader = DOSHeader.Parse(reader);
var dosStubSize = (int)(DOSHeader.CoffHeaderOffset - reader.BaseStream.Position);
_dosStubBytes = reader.ReadBytes(dosStubSize);
COFFHeader = COFFHeader.Parse(reader);
PEHeaderOffset = (uint)reader.BaseStream.Position;
PEHeader = PEHeader.Parse(reader);
for (var i = 0; i < COFFHeader.NumberOfSections; i++)
{
SectionHeaders.Add(PESectionHeader.Parse(reader));
}
var fillerSize = (int)(SectionHeaders[0].PointerToRawData - reader.BaseStream.Position);
_filler = reader.ReadBytes(fillerSize);
for (var i = 0; i < COFFHeader.NumberOfSections; i++)
{
var sectionBytes = reader.ReadBytes((int)SectionHeaders[i].SizeOfRawData);
Sections.Add(sectionBytes);
}
var remainingByteCount = (int)(reader.BaseStream.Length - reader.BaseStream.Position);
_remainingBytes = reader.ReadBytes(remainingByteCount);
// file ends here
// Parse Import Directory:
var importDirectoryEntry = PEHeader.DataDirectories[(int)DataDirectoryName.Import];
if (importDirectoryEntry.VirtualAddress > 0)
{
var importDirectoryFileOffset = GetOffsetFromRVA(importDirectoryEntry.VirtualAddress);
reader.BaseStream.Seek(importDirectoryFileOffset, SeekOrigin.Begin);
ImportDirectory = ImportDirectory.Parse(reader);
}
}
