Dump system firmware tables.

SystemFirmwareTables.cs

using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Text;

namespace ConsoleApp1
{
    internal class Program
    {
        static void Main()
        {
            Console.WriteLine("ACPI");
            foreach (var name in FirmwareTable.EnumerateTables(FirmwareTableProviderSignature.ACPI))
            {
                Console.WriteLine(" " + name);
                FirmwareTable.GetTableBytes(FirmwareTableProviderSignature.ACPI, name);
            }

            Console.WriteLine("RSMB");
            foreach (var name in FirmwareTable.EnumerateTables(FirmwareTableProviderSignature.RSMB))
            {
                Console.WriteLine(" " + name);
                FirmwareTable.GetTableBytes(FirmwareTableProviderSignature.ACPI, name);
            }

            Console.WriteLine("FIRM");
            foreach (var name in FirmwareTable.EnumerateTables(FirmwareTableProviderSignature.FIRM))
            {
                Console.WriteLine(" " + name);
                FirmwareTable.GetTableBytes(FirmwareTableProviderSignature.ACPI, name);
            }
        }

        public static class FirmwareTable
        {
            public static byte[] GetTableBytes(FirmwareTableProviderSignature signature, string table) => GetTableBytes(signature, table[3] << 24 | table[2] << 16 | table[1] << 8 | table[0]);
            public static byte[] GetTableBytes(FirmwareTableProviderSignature signature, int table)
            {
                var size = GetSystemFirmwareTable(signature, table, IntPtr.Zero, 0);
                if (size <= 0)
                    return null;

                var ptr = Marshal.AllocHGlobal(size);
                try
                {
                    GetSystemFirmwareTable(signature, table, ptr, size);
                    if (Marshal.GetLastWin32Error() != 0)
                        return null;

                    var buffer = new byte[size];
                    Marshal.Copy(ptr, buffer, 0, size);
                    return buffer;
                }
                finally
                {
                    Marshal.FreeHGlobal(ptr);
                }
            }

            public static IReadOnlyList<string> EnumerateTables(FirmwareTableProviderSignature provider)
            {
                var size = EnumSystemFirmwareTables(provider, IntPtr.Zero, 0);
                if (size <= 0)
                    return Array.Empty<string>();

                var ptr = Marshal.AllocHGlobal(size);
                try
                {
                    EnumSystemFirmwareTables(provider, ptr, size);
                    var buffer = new byte[size];
                    Marshal.Copy(ptr, buffer, 0, size);

                    var list = new string[size / 4];
                    for (var i = 0; i < list.Length; i++)
                    {
                        list[i] = Encoding.ASCII.GetString(buffer, 4 * i, 4);
                    }
                    return list;
                }
                finally
                {
                    Marshal.FreeHGlobal(ptr);
                }
            }

            [DllImport("kernel32")]
            private static extern int GetSystemFirmwareTable(FirmwareTableProviderSignature FirmwareTableProviderSignature, int FirmwareTableID, IntPtr pFirmwareTableBuffer, int BufferSize);

            [DllImport("kernel32")]
            private static extern int EnumSystemFirmwareTables(FirmwareTableProviderSignature FirmwareTableProviderSignature, IntPtr pFirmwareTableEnumBuffer, int BufferSize);
        }

        public enum FirmwareTableProviderSignature : int
        {
            ACPI = (byte)'A' << 24 | (byte)'C' << 16 | (byte)'P' << 8 | (byte)'I',
            FIRM = (byte)'F' << 24 | (byte)'I' << 16 | (byte)'R' << 8 | (byte)'M',
            RSMB = (byte)'R' << 24 | (byte)'S' << 16 | (byte)'M' << 8 | (byte)'B'
        }
    }
}