using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using ELFSharp.ELF;
using ELFSharp.ELF.Sections;
using System.IO;

class Program
{
    static void Main(string[] args)
    {
        string path = @"gdeliveryd";
        var elf = ELFReader.Load(path);
        var function = ((ISymbolTable)elf.GetSection(".symtab")).Entries
            .FirstOrDefault(ent =>
                ent.Type == SymbolType.Function &&
                ent.Name == "_ZN4GNET11GetSavedMsg7ProcessEPNS_8Protocol7ManagerEj"
            );
        if (function == null)
            throw new Exception("Function does not exists.");
        int address = int.Parse(function.ToString().Split(new [] { ": 0x" }, StringSplitOptions.None)[1].Split(',')[0], System.Globalization.NumberStyles.HexNumber) - 0x8048000;
        elf.Dispose();
        using (var writer = File.OpenWrite(path))
        {
            writer.Seek(address, SeekOrigin.Begin);
            writer.WriteByte(0xC3);
        }
    }
}