FirmwareRegionAnalyzer.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Diagnostics;

namespace ProcessorEmulator
{
    /// <summary>
    /// Firmware region detection and analysis system that identifies firmware components
    /// (bootloader, kernel, rootfs, assets) and provides emulation boot logic recommendations.
    /// </summary>
    public class FirmwareRegionAnalyzer
    {
        private static readonly Dictionary<string, RegionSignature> RegionSignatures = new()
        {
            // Bootloader region signatures
            ["BOOTLOADER"] = new RegionSignature
            {
                Name = "Bootloader",
                Type = FirmwareRegionType.Bootloader,
                Priority = 1,
                LoadAddress = 0x00000000,
                Description = "Primary bootloader (U-Boot, VxWorks boot, etc.)",
                Signatures = new[] { "U-Boot", "VxWorks", "bootrom", "loader", "boot" },
                BinaryPatterns = new[]
                {
                    new byte[] { 0x27, 0x05, 0x19, 0x56 }, // U-Boot magic
                    new byte[] { 0x02, 0x00, 0x00, 0x00 }, // VxWorks magic
                    new byte[] { 0x7F, 0x45, 0x4C, 0x46 }  // ELF header
                },
                RequiredEmulatorSetup = new[] { "InitializeBootEnvironment", "LoadBootloaderImage" }
            },

            // Linux kernel signatures
            ["KERNEL"] = new RegionSignature
            {
                Name = "Kernel",
                Type = FirmwareRegionType.Kernel,
                Priority = 2,
                LoadAddress = 0x80000000,
                Description = "Linux kernel image or VxWorks kernel",
                Signatures = new[] { "Linux version", "kernel", "vmlinux", "zImage", "uImage" },
                BinaryPatterns = new[]
                {
                    new byte[] { 0x1F, 0x8B, 0x08 },      // gzip header
                    new byte[] { 0x27, 0x05, 0x19, 0x56 }, // U-Boot wrapper
                    new byte[] { 0x00, 0x00, 0xA0, 0xE1 }  // ARM NOP instruction
                },
                RequiredEmulatorSetup = new[] { "LoadKernelImage", "SetupKernelEnvironment", "InitializeMMU" }
            },

            // Root filesystem signatures
            ["ROOTFS"] = new RegionSignature
            {
                Name = "Root Filesystem",
                Type = FirmwareRegionType.RootFs,
                Priority = 3,
                LoadAddress = 0x40000000,
                Description = "Root filesystem (SquashFS, CramFS, JFFS2, etc.)",
                Signatures = new[] { "bin/", "sbin/", "usr/", "etc/", "var/", "dev/" },
                BinaryPatterns = new[]
                {
                    new byte[] { 0x68, 0x73, 0x71, 0x73 }, // SquashFS magic
                    new byte[] { 0x45, 0x3D, 0xCD, 0x28 }, // CramFS magic
                    new byte[] { 0x19, 0x85 },             // JFFS2 magic
                    new byte[] { 0x55, 0x42, 0x49, 0x23 }  // UBIFS magic
                },
                RequiredEmulatorSetup = new[] { "MountRootFilesystem", "InitializeVFS", "SetupDeviceNodes" }
            },

            // Application/asset region
            ["ASSETS"] = new RegionSignature
            {
                Name = "Assets/Applications",
                Type = FirmwareRegionType.Assets,
                Priority = 4,
                LoadAddress = 0x20000000,
                Description = "Application binaries, configuration files, media assets",
                Signatures = new[] { ".so", ".conf", ".xml", ".png", ".jpg", "app/", "opt/" },
                BinaryPatterns = new[]
                {
                    new byte[] { 0x7F, 0x45, 0x4C, 0x46 }, // ELF library
                    new byte[] { 0x89, 0x50, 0x4E, 0x47 }, // PNG header
                    new byte[] { 0xFF, 0xD8, 0xFF }        // JPEG header
                },
                RequiredEmulatorSetup = new[] { "LoadApplications", "SetupLibraryPaths" }
            },

            // NVRAM/Config region
            ["NVRAM"] = new RegionSignature
            {
                Name = "NVRAM/Config",
                Type = FirmwareRegionType.Config,
                Priority = 5,
                LoadAddress = 0x10000000,
                Description = "Non-volatile configuration data",
                Signatures = new[] { "nvram", "config", "settings", "persistent" },
                BinaryPatterns = new[]
                {
                    new byte[] { 0x4E, 0x56, 0x52, 0x4D }, // "NVRM" header
                    new byte[] { 0x43, 0x46, 0x47, 0x00 }  // "CFG" header
                },
                RequiredEmulatorSetup = new[] { "InitializeNVRAM", "LoadConfiguration" }
            }
        };

        public static FirmwareRegionAnalysisResult AnalyzeFirmware(string firmwarePath)
        {
            var result = new FirmwareRegionAnalysisResult
            {
                FirmwarePath = firmwarePath,
                Success = false
            };

            try
            {
                if (!File.Exists(firmwarePath))
                {
                    result.Error = "Firmware file not found";
                    return result;
                }

                Debug.WriteLine($"[RegionAnalyzer] Analyzing firmware regions in: {firmwarePath}");

                var fileInfo = new FileInfo(firmwarePath);
                result.TotalSize = fileInfo.Length;

                // Read firmware file for analysis
                using var fs = new FileStream(firmwarePath, FileMode.Open, FileAccess.Read);
                var buffer = new byte[Math.Min(2 * 1024 * 1024, fs.Length)]; // Max 2MB sample
                var bytesRead = fs.Read(buffer, 0, buffer.Length);

                // Analyze regions
                result.DetectedRegions = AnalyzeRegions(buffer, bytesRead);
                
                // Generate emulation recommendations
                result.EmulationRecommendations = GenerateEmulationRecommendations(result.DetectedRegions);
                
                // Determine boot sequence
                result.BootSequence = DetermineBootSequence(result.DetectedRegions);

                result.Success = true;
                Debug.WriteLine($"[RegionAnalyzer] Analysis complete: {result.DetectedRegions.Count} regions detected");

                return result;
            }
            catch (Exception ex)
            {
                result.Error = $"Analysis failed: {ex.Message}";
                Debug.WriteLine($"[RegionAnalyzer] Error: {ex.Message}");
                return result;
            }
        }

        private static List<DetectedRegion> AnalyzeRegions(byte[] buffer, int length)
        {
            var detectedRegions = new List<DetectedRegion>();

            // Convert buffer to string for text-based analysis
            var content = Encoding.ASCII.GetString(buffer, 0, length)
                .Where(c => c >= 32 && c <= 126) // Printable ASCII only
                .Aggregate(new StringBuilder(), (sb, c) => sb.Append(c))
                .ToString()
                .ToLowerInvariant();

            foreach (var signature in RegionSignatures.Values)
            {
                var region = AnalyzeRegionSignature(content, buffer, length, signature);
                if (region != null)
                {
                    detectedRegions.Add(region);
                }
            }

            // Sort by priority and confidence
            return detectedRegions
                .OrderBy(r => r.Priority)
                .ThenByDescending(r => r.Confidence)
                .ToList();
        }

        private static DetectedRegion AnalyzeRegionSignature(string content, byte[] buffer, int length, RegionSignature signature)
        {
            float confidence = 0.0f;
            var evidenceList = new List<string>();

            // Text-based signature matching
            foreach (var textSig in signature.Signatures)
            {
                if (content.Contains(textSig.ToLowerInvariant()))
                {
                    confidence += 0.2f;
                    evidenceList.Add($"Text signature: '{textSig}'");
                }
            }

            // Binary pattern matching
            foreach (var pattern in signature.BinaryPatterns)
            {
                if (SearchBinaryPattern(buffer, length, pattern))
                {
                    confidence += 0.3f;
                    evidenceList.Add($"Binary pattern: {BitConverter.ToString(pattern)}");
                }
            }

            // Minimum confidence threshold
            if (confidence < 0.15f)
                return null;

            // Estimate region offset and size (simplified heuristic)
            uint estimatedOffset = EstimateRegionOffset(buffer, length, signature);
            uint estimatedSize = EstimateRegionSize(buffer, length, signature, estimatedOffset);

            return new DetectedRegion
            {
                Name = signature.Name,
                Type = signature.Type,
                Priority = signature.Priority,
                Confidence = Math.Min(confidence, 1.0f),
                Description = signature.Description,
                EstimatedOffset = estimatedOffset,
                EstimatedSize = estimatedSize,
                LoadAddress = signature.LoadAddress,
                Evidence = evidenceList,
                RequiredEmulatorSetup = signature.RequiredEmulatorSetup.ToList()
            };
        }

        private static bool SearchBinaryPattern(byte[] haystack, int length, byte[] needle)
        {
            for (int i = 0; i <= length - needle.Length; i++)
            {
                bool found = true;
                for (int j = 0; j < needle.Length; j++)
                {
                    if (haystack[i + j] != needle[j])
                    {
                        found = false;
                        break;
                    }
                }
                if (found) return true;
            }
            return false;
        }

        private static uint EstimateRegionOffset(byte[] buffer, int length, RegionSignature signature)
        {
            // Simple heuristic: look for first signature match
            foreach (var pattern in signature.BinaryPatterns)
            {
                for (int i = 0; i <= length - pattern.Length; i++)
                {
                    bool found = true;
                    for (int j = 0; j < pattern.Length; j++)
                    {
                        if (buffer[i + j] != pattern[j])
                        {
                            found = false;
                            break;
                        }
                    }
                    if (found) return (uint)i;
                }
            }
            return 0;
        }

        private static uint EstimateRegionSize(byte[] buffer, int length, RegionSignature signature, uint offset)
        {
            // Simplified size estimation based on region type
            return signature.Type switch
            {
                FirmwareRegionType.Bootloader => 256 * 1024,   // 256KB typical
                FirmwareRegionType.Kernel => 4 * 1024 * 1024,  // 4MB typical
                FirmwareRegionType.RootFs => 32 * 1024 * 1024, // 32MB typical
                FirmwareRegionType.Assets => 8 * 1024 * 1024,  // 8MB typical
                FirmwareRegionType.Config => 64 * 1024,        // 64KB typical
                _ => 1024 * 1024 // 1MB default
            };
        }

        private static List<string> GenerateEmulationRecommendations(List<DetectedRegion> regions)
        {
            var recommendations = new List<string>();

            if (regions.Any())
            {
                recommendations.Add("📋 Emulation Configuration Recommendations:");
                recommendations.Add("");

                foreach (var region in regions.OrderBy(r => r.Priority))
                {
                    recommendations.Add($"🔸 {region.Name} (confidence: {region.Confidence:P1})");
                    recommendations.Add($"   Load Address: 0x{region.LoadAddress:X8}");
                    recommendations.Add($"   Estimated Size: {region.EstimatedSize / 1024}KB");
                    
                    if (region.RequiredEmulatorSetup.Any())
                    {
                        recommendations.Add($"   Required Setup: {string.Join(", ", region.RequiredEmulatorSetup)}");
                    }
                    recommendations.Add("");
                }
            }
            else
            {
                recommendations.Add("⚠️ No firmware regions detected with sufficient confidence");
                recommendations.Add("Consider manual configuration or use generic emulation settings");
            }

            return recommendations;
        }

        private static List<string> DetermineBootSequence(List<DetectedRegion> regions)
        {
            var bootSequence = new List<string>();

            // Standard embedded boot sequence
            var bootloader = regions.FirstOrDefault(r => r.Type == FirmwareRegionType.Bootloader);
            var kernel = regions.FirstOrDefault(r => r.Type == FirmwareRegionType.Kernel);
            var rootfs = regions.FirstOrDefault(r => r.Type == FirmwareRegionType.RootFs);
            var config = regions.FirstOrDefault(r => r.Type == FirmwareRegionType.Config);
            var assets = regions.FirstOrDefault(r => r.Type == FirmwareRegionType.Assets);

            bootSequence.Add("🚀 Recommended Boot Sequence:");
            bootSequence.Add("");

            if (bootloader != null)
            {
                bootSequence.Add($"1. Load Bootloader @ 0x{bootloader.LoadAddress:X8}");
                bootSequence.Add("   - Initialize hardware");
                bootSequence.Add("   - Setup memory controllers");
                bootSequence.Add("   - Initialize peripherals");
            }

            if (config != null)
            {
                bootSequence.Add($"2. Load Configuration @ 0x{config.LoadAddress:X8}");
                bootSequence.Add("   - Read NVRAM settings");
                bootSequence.Add("   - Apply hardware configuration");
            }

            if (kernel != null)
            {
                bootSequence.Add($"3. Load Kernel @ 0x{kernel.LoadAddress:X8}");
                bootSequence.Add("   - Initialize kernel subsystems");
                bootSequence.Add("   - Setup virtual memory");
                bootSequence.Add("   - Load device drivers");
            }

            if (rootfs != null)
            {
                bootSequence.Add($"4. Mount Root Filesystem @ 0x{rootfs.LoadAddress:X8}");
                bootSequence.Add("   - Mount filesystem");
                bootSequence.Add("   - Initialize system services");
            }

            if (assets != null)
            {
                bootSequence.Add($"5. Load Applications @ 0x{assets.LoadAddress:X8}");
                bootSequence.Add("   - Load application binaries");
                bootSequence.Add("   - Start system applications");
            }

            if (!regions.Any())
            {
                bootSequence.Add("⚠️ No clear boot sequence detected");
                bootSequence.Add("Consider using generic boot sequence");
            }

            return bootSequence;
        }
    }

    public enum FirmwareRegionType
    {
        Bootloader,
        Kernel,
        RootFs,
        Assets,
        Config,
        Unknown
    }

    public class RegionSignature
    {
        public string Name { get; set; } = "";
        public FirmwareRegionType Type { get; set; }
        public int Priority { get; set; }
        public uint LoadAddress { get; set; }
        public string Description { get; set; } = "";
        public string[] Signatures { get; set; } = Array.Empty<string>();
        public byte[][] BinaryPatterns { get; set; } = Array.Empty<byte[]>();
        public string[] RequiredEmulatorSetup { get; set; } = Array.Empty<string>();
    }

    public class DetectedRegion
    {
        public string Name { get; set; } = "";
        public FirmwareRegionType Type { get; set; }
        public int Priority { get; set; }
        public float Confidence { get; set; }
        public string Description { get; set; } = "";
        public uint EstimatedOffset { get; set; }
        public uint EstimatedSize { get; set; }
        public uint LoadAddress { get; set; }
        public List<string> Evidence { get; set; } = new();
        public List<string> RequiredEmulatorSetup { get; set; } = new();
    }

    public class FirmwareRegionAnalysisResult
    {
        public bool Success { get; set; }
        public string Error { get; set; } = "";
        public string FirmwarePath { get; set; } = "";
        public long TotalSize { get; set; }
        public List<DetectedRegion> DetectedRegions { get; set; } = new();
        public List<string> EmulationRecommendations { get; set; } = new();
        public List<string> BootSequence { get; set; } = new();
    }
}