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protodec
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Various improvements 

including but not limited to:
- Move parsing logic to library project
- Expanding coverage of the proto3 spec
- Option to parse types from only a specified assembly
- More accurate field name translation
- Accept custom lookup functions for types and names
- Some resilience to obfuscation
- Fix infinite recursion bug causing stack overflow
This commit is contained in:
Xpl0itR 2023-10-31 02:30:03 +00:00
parent 253983430d
commit b1eed86d6c
Signed by: Xpl0itR
GPG Key ID: 91798184109676AD
16 changed files with 552 additions and 380 deletions
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62
AssemblyInspector.cs
View File

@ -1,62 +0,0 @@
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.InteropServices;
using CommunityToolkit.Diagnostics;
namespace protodec;
public sealed class AssemblyInspector : IDisposable
{
private const string DllPattern = "*.dll";
private readonly MetadataLoadContext _assemblyContext;
private readonly string[] _assemblyPaths;
private readonly Type _googleProtobufIMessage;
public AssemblyInspector(string assemblyPath, bool includeRuntimeAssemblies)
{
if (File.Exists(assemblyPath))
{
_assemblyPaths = new[] { assemblyPath };
}
else if (Directory.Exists(assemblyPath))
{
_assemblyPaths = Directory.EnumerateFiles(assemblyPath, DllPattern).ToArray();
}
else
{
ThrowHelper.ThrowArgumentOutOfRangeException(assemblyPath);
}
PathAssemblyResolver resolver = new(includeRuntimeAssemblies ? ConcatRuntimeAssemblyPaths(_assemblyPaths) : _assemblyPaths);
_assemblyContext = new MetadataLoadContext(resolver);
_googleProtobufIMessage = _assemblyContext.LoadFromAssemblyName("Google.Protobuf")
.GetType("Google.Protobuf.IMessage")!;
}
public IEnumerable<Type> GetProtobufMessageTypes() =>
from assemblyPath
in _assemblyPaths
from type
in _assemblyContext.LoadFromAssemblyPath(assemblyPath).GetTypes()
where type.IsSealed
&& type.Namespace != "Google.Protobuf.Reflection"
&& type.Namespace != "Google.Protobuf.WellKnownTypes"
&& type.IsAssignableTo(_googleProtobufIMessage)
select type;
public void Dispose() =>
_assemblyContext.Dispose();
private static IEnumerable<string> ConcatRuntimeAssemblyPaths(IEnumerable<string> paths)
{
string path = RuntimeEnvironment.GetRuntimeDirectory();
return Directory.EnumerateFiles(path, DllPattern)
.Concat(paths);
}
}

12
IWriteable.cs
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@ -1,12 +0,0 @@
using System.CodeDom.Compiler;
namespace protodec;
public interface IWritable
{
string Name { get; }
void WriteFileTo(IndentedTextWriter writer);
void WriteTo(IndentedTextWriter writer);
}

43
LibProtodec/AssemblyInspector.cs Normal file
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@ -0,0 +1,43 @@
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
namespace LibProtodec;
public sealed class AssemblyInspector : IDisposable
{
public readonly MetadataLoadContext AssemblyContext;
public readonly IReadOnlyList<Type> LoadedTypes;
public AssemblyInspector(string assemblyDir, string? assemblyName = null)
{
string[] assemblyPaths = Directory.EnumerateFiles(assemblyDir, searchPattern: "*.dll")
.ToArray();
AssemblyContext = new MetadataLoadContext(
new PathAssemblyResolver(assemblyPaths));
LoadedTypes = assemblyName is null
? assemblyPaths.SelectMany(path => AssemblyContext.LoadFromAssemblyPath(path).GetTypes()).ToList()
: AssemblyContext.LoadFromAssemblyName(assemblyName).GetTypes();
}
public IEnumerable<Type> GetProtobufMessageTypes()
{
Type googleProtobufIMessage = AssemblyContext.LoadFromAssemblyName("Google.Protobuf")
.GetType("Google.Protobuf.IMessage")!;
return from type
in LoadedTypes
where !type.IsNested
&& type.IsSealed
&& type.Namespace != "Google.Protobuf.Reflection"
&& type.Namespace != "Google.Protobuf.WellKnownTypes"
&& type.IsAssignableTo(googleProtobufIMessage)
select type;
}
public void Dispose() =>
AssemblyContext.Dispose();
}

19
ProtobufEnum.cs → LibProtodec/Enum.cs
View File

@ -1,25 +1,30 @@
using System.CodeDom.Compiler; using System.CodeDom.Compiler;
using System.Collections.Generic; using System.Collections.Generic;
namespace protodec; namespace LibProtodec;
public sealed record ProtobufEnum(string Name) : IWritable public sealed class Enum : Protobuf
{ {
public readonly Dictionary<int, string> Fields = new(); public readonly List<KeyValuePair<int, string>> Fields = new();
public void WriteFileTo(IndentedTextWriter writer) public override void WriteFileTo(IndentedTextWriter writer)
{ {
Protodec.WritePreambleTo(writer); this.WritePreambleTo(writer);
WriteTo(writer); WriteTo(writer);
} }
public void WriteTo(IndentedTextWriter writer) public override void WriteTo(IndentedTextWriter writer)
{ {
writer.Write("enum "); writer.Write("enum ");
writer.Write(Name); writer.Write(this.Name);
writer.WriteLine(" {"); writer.WriteLine(" {");
writer.Indent++; writer.Indent++;
if (Fields.ContainsDuplicateKey())
{
writer.WriteLine("""option allow_alias = true;""");
}
foreach ((int id, string name) in Fields) foreach ((int id, string name) in Fields)
{ {
writer.Write(name); writer.Write(name);

57
StringExtensions.cs → LibProtodec/Extensions.cs
View File

@ -1,25 +1,35 @@
using System.Runtime.CompilerServices; using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
namespace protodec; namespace LibProtodec;
public static class StringExtensions public static class Extensions
{ {
[MethodImpl(MethodImplOptions.AggressiveInlining)] public static void Add<TKey, TValue>(this ICollection<KeyValuePair<TKey, TValue>> keyValuePairs, TKey key, TValue value) =>
public static int CountUpper(this string str, int i = 0) keyValuePairs.Add(new KeyValuePair<TKey, TValue>(key, value));
public static bool ContainsDuplicateKey<TKey, TValue>(
this IEnumerable<KeyValuePair<TKey, TValue>> keyValuePairs,
IEqualityComparer<TKey>? comparer = null)
{ {
int upper = 0; HashSet<TKey> set = new(5, comparer);
for (; i < str.Length; i++) foreach (KeyValuePair<TKey, TValue> kvp in keyValuePairs)
if (char.IsAsciiLetterUpper(str[i])) {
upper++; if (!set.Add(kvp.Key))
{
return upper; return true;
}
} }
[MethodImpl(MethodImplOptions.AggressiveInlining)] return false;
// ReSharper disable once IdentifierTypo }
public static bool IsBeebyted(this string name) =>
name.Length == 11 && CountUpper(name) == 11; public static string TrimEnd(this string @string, string trimStr) =>
@string.EndsWith(trimStr, StringComparison.Ordinal)
? @string[..^trimStr.Length]
: @string;
public static string ToSnakeCaseLower(this string str) => public static string ToSnakeCaseLower(this string str) =>
string.Create(str.Length + CountUpper(str, 1), str, (newString, oldString) => string.Create(str.Length + CountUpper(str, 1), str, (newString, oldString) =>
@ -64,4 +74,21 @@ public static class StringExtensions
} }
} }
}); });
[MethodImpl(MethodImplOptions.AggressiveInlining)]
// ReSharper disable once IdentifierTypo
public static bool IsBeebyted(this string name) =>
name.Length == 11 && CountUpper(name) == 11;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static int CountUpper(this string str, int i = 0)
{
int upper = 0;
for (; i < str.Length; i++)
if (char.IsAsciiLetterUpper(str[i]))
upper++;
return upper;
}
} }

25
LibProtodec/LibProtodec.csproj Normal file
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@ -0,0 +1,25 @@
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<Authors>Xpl0itR</Authors>
<Copyright>Copyright © 2023 Xpl0itR</Copyright>
<Description>A library to decompile protobuf parser/serializer classes compiled by protoc, from dotnet assemblies back into .proto definitions</Description>
<IncludeSymbols>true</IncludeSymbols>
<IsPackable>true</IsPackable>
<LangVersion>11</LangVersion>
<Nullable>enable</Nullable>
<OutputType>Library</OutputType>
<PackageLicenseExpression>MPL-2.0</PackageLicenseExpression>
<PackageRequireLicenseAcceptance>true</PackageRequireLicenseAcceptance>
<PublishRepositoryUrl>true</PublishRepositoryUrl>
<SymbolPackageFormat>snupkg</SymbolPackageFormat>
<TargetFramework>net7.0</TargetFramework>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="CommunityToolkit.Diagnostics" Version="8.2.2" />
<PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.1.1" PrivateAssets="All" />
<PackageReference Include="System.Reflection.MetadataLoadContext" Version="7.0.0" />
</ItemGroup>
</Project>

45
ProtobufMessage.cs → LibProtodec/Message.cs
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@ -3,18 +3,18 @@ using System.Collections.Generic;
using System.IO; using System.IO;
using System.Linq; using System.Linq;
namespace protodec; namespace LibProtodec;
public sealed record ProtobufMessage(string Name) : IWritable public sealed class Message : Protobuf
{ {
public readonly HashSet<string> Imports = new(); public readonly HashSet<string> Imports = new();
public readonly Dictionary<string, int[]> OneOfs = new(); public readonly Dictionary<string, int[]> OneOfs = new();
public readonly Dictionary<int, (string Type, string Name)> Fields = new(); public readonly Dictionary<int, (bool IsOptional, string Type, string Name)> Fields = new();
public readonly Dictionary<string, IWritable> Nested = new(); public readonly Dictionary<string, Protobuf> Nested = new();
public void WriteFileTo(IndentedTextWriter writer) public override void WriteFileTo(IndentedTextWriter writer)
{ {
Protodec.WritePreambleTo(writer); this.WritePreambleTo(writer);
if (Imports.Count > 0) if (Imports.Count > 0)
{ {
@ -31,13 +31,23 @@ public sealed record ProtobufMessage(string Name) : IWritable
WriteTo(writer); WriteTo(writer);
} }
public void WriteTo(IndentedTextWriter writer) public override void WriteTo(IndentedTextWriter writer)
{ {
writer.Write("message "); writer.Write("message ");
writer.Write(Name); writer.Write(this.Name);
writer.WriteLine(" {"); writer.WriteLine(" {");
writer.Indent++; writer.Indent++;
int[] oneOfs = OneOfs.SelectMany(oneOf => oneOf.Value).ToArray();
foreach ((int fieldId, (bool, string, string) field) in Fields)
{
if (oneOfs.Contains(fieldId))
continue;
WriteField(writer, fieldId, field);
}
foreach ((string name, int[] fieldIds) in OneOfs) foreach ((string name, int[] fieldIds) in OneOfs)
{ {
// ReSharper disable once StringLiteralTypo // ReSharper disable once StringLiteralTypo
@ -55,17 +65,7 @@ public sealed record ProtobufMessage(string Name) : IWritable
writer.WriteLine('}'); writer.WriteLine('}');
} }
int[] oneOfs = OneOfs.SelectMany(oneOf => oneOf.Value).ToArray(); foreach (Protobuf nested in Nested.Values)
foreach ((int fieldId, (string, string) field) in Fields)
{
if (oneOfs.Contains(fieldId))
continue;
WriteField(writer, fieldId, field);
}
foreach (IWritable nested in Nested.Values)
{ {
nested.WriteTo(writer); nested.WriteTo(writer);
writer.WriteLine(); writer.WriteLine();
@ -75,8 +75,13 @@ public sealed record ProtobufMessage(string Name) : IWritable
writer.Write('}'); writer.Write('}');
} }
private static void WriteField(TextWriter writer, int fieldId, (string Type, string Name) field) private static void WriteField(TextWriter writer, int fieldId, (bool IsOptional, string Type, string Name) field)
{ {
if (field.IsOptional)
{
writer.Write("optional ");
}
writer.Write(field.Type); writer.Write(field.Type);
writer.Write(' '); writer.Write(' ');
writer.Write(field.Name); writer.Write(field.Name);

41
LibProtodec/Protobuf.cs Normal file
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@ -0,0 +1,41 @@
using System.CodeDom.Compiler;
using System.IO;
namespace LibProtodec;
public abstract class Protobuf
{
public required string Name { get; init; }
public string? AssemblyName { get; init; }
public string? Namespace { get; init; }
public abstract void WriteFileTo(IndentedTextWriter writer);
public abstract void WriteTo(IndentedTextWriter writer);
protected void WritePreambleTo(TextWriter writer) =>
WritePreambleTo(writer, AssemblyName, Namespace);
// ReSharper disable once MethodOverloadWithOptionalParameter
public static void WritePreambleTo(TextWriter writer, string? assemblyName = null, string? @namespace = null)
{
writer.WriteLine("// Decompiled with protodec");
if (assemblyName is not null)
{
writer.Write("// Assembly: ");
writer.WriteLine(assemblyName);
}
writer.WriteLine();
writer.WriteLine("""syntax = "proto3";""");
writer.WriteLine();
if (@namespace is not null)
{
writer.WriteLine($"""option csharp_namespace = "{@namespace}";""");
writer.WriteLine();
}
}
}

272
LibProtodec/Protodec.cs Normal file
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@ -0,0 +1,272 @@
using System;
using System.CodeDom.Compiler;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Reflection;
using CommunityToolkit.Diagnostics;
namespace LibProtodec;
public sealed class Protodec
{
public delegate bool LookupFunc(string key, [MaybeNullWhen(false)] out string value);
private readonly Dictionary<string, Protobuf> _protobufs;
private readonly HashSet<string> _currentDescent;
public Protodec()
{
_protobufs = new Dictionary<string, Protobuf>();
_currentDescent = new HashSet<string>();
}
public LookupFunc? CustomTypeLookup { get; init; }
public LookupFunc? CustomNameLookup { get; init; }
public IReadOnlyDictionary<string, Protobuf> Protobufs =>
_protobufs;
public void WriteAllTo(IndentedTextWriter writer)
{
Protobuf.WritePreambleTo(writer);
foreach (Protobuf proto in _protobufs.Values)
{
proto.WriteTo(writer);
writer.WriteLine();
writer.WriteLine();
}
}
public void ParseMessage(Type type, bool skipEnums = false)
{
Guard.IsTrue(type.IsClass);
ParseMessageInternal(type, skipEnums, null);
_currentDescent.Clear();
}
public void ParseEnum(Type type)
{
Guard.IsTrue(type.IsEnum);
ParseEnumInternal(type, null);
_currentDescent.Clear();
}
private bool IsParsed(Type type, Message? parentMessage, out Dictionary<string, Protobuf> protobufs)
{
protobufs = parentMessage is not null && type.IsNested
? parentMessage.Nested
: _protobufs;
return protobufs.ContainsKey(type.Name)
|| !_currentDescent.Add(type.Name);
}
private void ParseMessageInternal(Type messageClass, bool skipEnums, Message? parentMessage)
{
if (IsParsed(messageClass, parentMessage, out Dictionary<string, Protobuf> protobufs))
{
return;
}
Message message = new()
{
Name = TranslateProtobufName(messageClass.Name),
AssemblyName = messageClass.Assembly.FullName,
Namespace = messageClass.Namespace
};
FieldInfo[] idFields = messageClass.GetFields(BindingFlags.Public | BindingFlags.Static);
PropertyInfo[] properties = messageClass.GetProperties(BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly);
for (int pi = 0, fi = 0; pi < properties.Length; pi++, fi++)
{
PropertyInfo property = properties[pi];
if (property.GetMethod is null || property.GetMethod.IsVirtual)
{
fi--;
continue;
}
Type propertyType = property.PropertyType;
// only OneOf enums are defined nested directly in the message class
if (propertyType.IsEnum && propertyType.DeclaringType?.Name == message.Name)
{
string oneOfName = TranslateOneOfName(property.Name);
int[] oneOfProtoFieldIds = propertyType.GetFields(BindingFlags.Public | BindingFlags.Static)
.Select(field => (int)field.GetRawConstantValue()!)
.Where(id => id > 0)
.ToArray();
message.OneOfs.Add(oneOfName, oneOfProtoFieldIds);
fi--;
continue;
}
FieldInfo idField = idFields[fi];
Guard.IsTrue(idField.IsLiteral);
Guard.IsEqualTo(idField.FieldType.Name, nameof(Int32));
int msgFieldId = (int)idField.GetRawConstantValue()!;
bool msgFieldIsOptional = false;
string msgFieldType = ParseFieldType(propertyType, skipEnums, message);
string msgFieldName = TranslateMessageFieldName(property.Name);
// optional protobuf fields will generate an additional "Has" get-only boolean property immediately after the real property
if (properties.Length > pi + 1 && properties[pi + 1].PropertyType.Name == nameof(Boolean) && !properties[pi + 1].CanWrite)
{
msgFieldIsOptional = true;
pi++;
}
message.Fields.Add(msgFieldId, (msgFieldIsOptional, msgFieldType, msgFieldName));
}
protobufs.Add(message.Name, message);
}
private void ParseEnumInternal(Type enumEnum, Message? parentMessage)
{
if (IsParsed(enumEnum, parentMessage, out Dictionary<string, Protobuf> protobufs))
{
return;
}
Enum @enum = new()
{
Name = TranslateProtobufName(enumEnum.Name),
AssemblyName = enumEnum.Assembly.FullName,
Namespace = enumEnum.Namespace
};
foreach (FieldInfo field in enumEnum.GetFields(BindingFlags.Public | BindingFlags.Static))
{
int enumFieldId = (int)field.GetRawConstantValue()!;
string enumFieldName = TranslateEnumFieldName(field, @enum.Name);
@enum.Fields.Add(enumFieldId, enumFieldName);
}
protobufs.Add(@enum.Name, @enum);
}
private string ParseFieldType(Type type, bool skipEnums, Message message)
{
switch (type.Name)
{
case "ByteString":
return "bytes";
case nameof(String):
return "string";
case nameof(Boolean):
return "bool";
case nameof(Double):
return "double";
case nameof(UInt32):
return "uint32";
case nameof(UInt64):
return "uint64";
case nameof(Int32):
return "int32";
case nameof(Int64):
return "int64";
case nameof(Single):
return "float";
}
switch (type.GenericTypeArguments.Length)
{
case 1:
string t = ParseFieldType(type.GenericTypeArguments[0], skipEnums, message);
return "repeated " + t;
case 2:
string t1 = ParseFieldType(type.GenericTypeArguments[0], skipEnums, message);
string t2 = ParseFieldType(type.GenericTypeArguments[1], skipEnums, message);
return $"map<{t1}, {t2}>";
}
if (CustomTypeLookup?.Invoke(type.Name, out string? fieldType) == true)
{
return fieldType;
}
if (type.IsEnum)
{
if (skipEnums)
{
return "int32";
}
ParseEnumInternal(type, message);
}
else
{
ParseMessageInternal(type, skipEnums, message);
}
if (!type.IsNested)
{
message.Imports.Add(type.Name);
}
return type.Name;
}
private string TranslateProtobufName(string name) =>
CustomNameLookup?.Invoke(name, out string? translatedName) == true
? translatedName
: name;
private string TranslateOneOfName(string oneOfEnumName) =>
TranslateName(oneOfEnumName, out string translatedName)
? translatedName.TrimEnd("Case")
: oneOfEnumName.TrimEnd("Case")
.ToSnakeCaseLower();
private string TranslateMessageFieldName(string fieldName) =>
TranslateName(fieldName, out string translatedName)
? translatedName
: fieldName.ToSnakeCaseLower();
private string TranslateEnumFieldName(FieldInfo field, string enumName)
{
if (field.GetCustomAttributesData()
.SingleOrDefault(attr => attr.AttributeType.Name == "OriginalNameAttribute")
?.ConstructorArguments[0]
.Value
is string originalName)
{
return originalName;
}
if (TranslateName(field.Name, out string translatedName))
{
return translatedName;
}
if (!enumName.IsBeebyted())
{
enumName = enumName.ToSnakeCaseUpper();
}
return enumName + '_' + field.Name.ToSnakeCaseUpper();
}
private bool TranslateName(string name, out string translatedName)
{
if (CustomNameLookup?.Invoke(name, out translatedName!) == true)
{
return true;
}
translatedName = name;
return name.IsBeebyted();
}
}

54
Program.cs
View File

@ -1,54 +0,0 @@
using System;
using System.CodeDom.Compiler;
using System.IO;
using System.Linq;
using protodec;
const string indent = " ";
const string help = """
Usage: protodec(.exe) <target_assembly_path> <out_path> [options]
Arguments:
target_assembly_path Either a single assembly or a directory of assemblies to be parsed.
out_path An existing directory to output into individual files, otherwise output to a single file.
Options:
--skip_enums Skip parsing enums and replace references to then with int32.
--include_runtime_assemblies Add the assemblies of the current runtime to the search path.
""";
if (args.Length < 2)
{
Console.WriteLine(help);
return;
}
string assembly = args[0];
string outPath = args[1];
bool runtime = args.Contains("--include_runtime_assemblies");
bool skipEnums = args.Contains("--skip_enums");
using AssemblyInspector inspector = new(assembly, runtime);
Protodec protodec = new();
foreach (Type message in inspector.GetProtobufMessageTypes())
{
protodec.ParseMessage(message, skipEnums);
}
outPath = Path.GetFullPath(outPath);
if (Directory.Exists(outPath))
{
foreach (IWritable proto in protodec.Messages.Values.Concat<IWritable>(protodec.Enums.Values))
{
using StreamWriter streamWriter = new(Path.Join(outPath, proto.Name + ".proto"));
using IndentedTextWriter indentWriter = new(streamWriter, indent);
proto.WriteFileTo(indentWriter);
}
}
else
{
using StreamWriter streamWriter = new(outPath);
using IndentedTextWriter indentWriter = new(streamWriter, indent);
protodec.WriteAllTo(indentWriter);
}

183
Protodec.cs
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@ -1,183 +0,0 @@
using System;
using System.CodeDom.Compiler;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.CompilerServices;
using CommunityToolkit.Diagnostics;
namespace protodec;
public sealed class Protodec
{
public readonly Dictionary<string, ProtobufMessage> Messages = new();
public readonly Dictionary<string, ProtobufEnum> Enums = new();
private const BindingFlags PublicStatic = BindingFlags.Public | BindingFlags.Static;
public void ParseMessage(Type messageClass, bool skipEnums = false)
{
Guard.IsTrue(messageClass.IsClass);
if (Messages.ContainsKey(messageClass.Name))
return;
ProtobufMessage message = new(messageClass.Name);
FieldInfo[] idFields = messageClass.GetFields(PublicStatic);
PropertyInfo[] properties = messageClass.GetProperties(BindingFlags.Public | BindingFlags.Instance);
for (int i = 0; i < properties.Length; i++)
{
Type propertyType = properties[i].PropertyType;
// only OneOf enums are defined nested directly in the message class
if (propertyType.IsEnum && propertyType.DeclaringType?.Name == messageClass.Name)
{
string oneOfName = TranslateMessageFieldName(properties[i].Name);
int[] oneOfProtoFieldIds = propertyType.GetFields(PublicStatic)
.Select(field => (int)field.GetRawConstantValue()!)
.Where(id => id > 0)
.ToArray();
message.OneOfs.Add(oneOfName, oneOfProtoFieldIds);
continue;
}
FieldInfo idField = idFields[i];
Guard.IsTrue(idField.IsLiteral);
Guard.IsEqualTo(idField.FieldType.Name, nameof(Int32));
int msgFieldId = (int)idField.GetRawConstantValue()!;
string msgFieldType = ParseType(propertyType, skipEnums, message);
string msgFieldName = TranslateMessageFieldName(properties[i].Name);
message.Fields.Add(msgFieldId, (msgFieldType, msgFieldName));
}
Messages.Add(message.Name, message);
}
private string ParseType(Type type, bool skipEnums, ProtobufMessage message)
{
switch (type.Name)
{
case "ByteString":
return "bytes";
case nameof(String):
return "string";
case nameof(Boolean):
return "bool";
case nameof(Double):
return "double";
case nameof(UInt32):
return "uint32";
case nameof(UInt64):
return "uint64";
case nameof(Int32):
return "int32";
case nameof(Int64):
return "int64";
case nameof(Single):
return "float";
case "RepeatedField`1":
string typeName = ParseType(type.GenericTypeArguments[0], skipEnums, message);
return "repeated " + typeName;
case "MapField`2":
string t1 = ParseType(type.GenericTypeArguments[0], skipEnums, message);
string t2 = ParseType(type.GenericTypeArguments[1], skipEnums, message);
return $"map<{t1}, {t2}>";
default:
{
if (type.IsEnum)
{
if (skipEnums)
return "int32";
ParseEnum(type, message);
}
else
{
ParseMessage(type, skipEnums);
}
message.Imports.Add(type.Name);
return type.Name;
}
}
}
private void ParseEnum(Type enumEnum, ProtobufMessage message)
{
if ((enumEnum.IsNested && message.Nested.ContainsKey(enumEnum.Name))
|| Enums.ContainsKey(enumEnum.Name))
return;
ProtobufEnum protoEnum = new(enumEnum.Name);
foreach (FieldInfo field in enumEnum.GetFields(PublicStatic))
{
int enumFieldId = (int)field.GetRawConstantValue()!;
string enumFieldName = field.GetCustomAttributesData()
.SingleOrDefault(attr => attr.AttributeType.Name == "OriginalNameAttribute")
?.ConstructorArguments[0]
.Value
as string
?? TranslateEnumFieldName(enumEnum.Name, field.Name);
protoEnum.Fields.Add(enumFieldId, enumFieldName);
}
if (enumEnum.IsNested)
{
message.Nested.Add(protoEnum.Name, protoEnum);
}
else
{
Enums.Add(protoEnum.Name, protoEnum);
}
}
public void WriteAllTo(IndentedTextWriter writer)
{
WritePreambleTo(writer);
foreach (IWritable proto in Messages.Values.Concat<IWritable>(Enums.Values))
{
proto.WriteTo(writer);
writer.WriteLine();
writer.WriteLine();
}
}
internal static void WritePreambleTo(TextWriter writer)
{
writer.WriteLine("// Decompiled with protodec");
writer.WriteLine();
writer.WriteLine("""syntax = "proto3";""");
writer.WriteLine();
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static string TranslateMessageFieldName(string name) =>
name.IsBeebyted() ? name : name.ToSnakeCaseLower();
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static string TranslateEnumFieldName(string enumName, string fieldName) =>
enumName.IsBeebyted()
? enumName + '_' + fieldName.ToSnakeCaseUpper()
: (enumName + fieldName).ToSnakeCaseUpper();
private bool TryParseWriteToMethod(Type targetClass)
{
//MethodInfo method = targetClass.GetInterface("Google.Protobuf.IBufferMessage")?.GetMethod("InternalWriteTo", BindingFlags.Public | BindingFlags.Instance)!;
byte[] cil = targetClass.GetMethod("WriteTo", BindingFlags.Public | BindingFlags.Instance)!
.GetMethodBody()!
.GetILAsByteArray()!;
if (cil[0] == 0x2A) // ret
{
return false;
}
throw new NotImplementedException();
}
}

17
README.md
View File

@ -5,23 +5,24 @@ A tool to decompile protobuf parser/serializer classes compiled by [protoc](http
Usage Usage
----- -----
``` ```
Usage: protodec(.exe) <target_assembly_path> <out_path> [options] Usage: protodec(.exe) <target_assembly_dir> <out_path> [target_assembly_name] [options]
Arguments: Arguments:
target_assembly_path Either a single assembly or a directory of assemblies to be parsed. target_assembly_dir A directory of assemblies to be loaded.
out_path An existing directory to output into individual files, otherwise output to a single file. out_path An existing directory to output into individual files, otherwise output to a single file.
target_assembly_name The name of an assembly to parse. If omitted, all assemblies in the target_assembly_dir will be parsed.
Options: Options:
--skip_enums Skip parsing enums and replace references to then with int32. --skip_enums Skip parsing enums and replace references to them with int32.
--include_runtime_assemblies Add the assemblies of the current runtime to the search path.
``` ```
Limitations Limitations
----------- -----------
- Integers are assumed to be (u)int32/64 as C# doesn't differentiate between them and sint32/64 and (s)fixed32/64. - Integers are assumed to be (u)int32/64 as C# doesn't differentiate between them and sint32/64 and (s)fixed32/64.
This could be solved by parsing the writer methods, however this wouldn't work on hollow assemblies such as DummyDlls produced by Il2CppDumper ### Decompiling from [Il2CppDumper](https://github.com/Perfare/Il2CppDumper) DummyDLLs
### Il2CppDumper - The `Name` parameter of `OriginalNameAttribute` is not dumped. In this case the C# names are used after conforming them to protobuf conventions
- The Name parameter of OriginalNameAttribute is not dumped. In this case the C# names are used after conforming them to protobuf conventions
- Dumped assemblies depend on strong-named core libs, however the ones dumped are not strong-named. - Dumped assemblies depend on strong-named core libs, however the ones dumped are not strong-named.
This interferes with loading and can be bypassed by loading the strong-named libs from your runtime by passing the `--include_runtime_assemblies` flag This interferes with loading and can be mitigated by copying the assemblies from your runtime into the target assembly directory.
I recommend using [Cpp2IL](https://github.com/SamboyCoding/Cpp2IL) instead of Il2CppDumper.
License License
------- -------

17
protodec.csproj
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@ -1,17 +0,0 @@
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<LangVersion>11</LangVersion>
<Nullable>enable</Nullable>
<OutputType>Exe</OutputType>
<RuntimeIdentifiers>win-x64;linux-x64</RuntimeIdentifiers>
<TargetFramework>net7.0</TargetFramework>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="ClrHeapAllocationAnalyzer" Version="3.0.0" PrivateAssets="all" />
<PackageReference Include="CommunityToolkit.Diagnostics" Version="8.2.0-preview2" />
<PackageReference Include="System.Reflection.MetadataLoadContext" Version="8.0.0-preview.3.23174.8" />
</ItemGroup>
</Project>

8
protodec.sln
View File

@ -3,7 +3,9 @@ Microsoft Visual Studio Solution File, Format Version 12.00
# Visual Studio Version 17 # Visual Studio Version 17
VisualStudioVersion = 17.6.33513.286 VisualStudioVersion = 17.6.33513.286
MinimumVisualStudioVersion = 10.0.40219.1 MinimumVisualStudioVersion = 10.0.40219.1
Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "protodec", "protodec.csproj", "{A5493BF4-F78C-4DCF-B449-D9A9A52FB5F0}" Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "protodec", "protodec\protodec.csproj", "{A5493BF4-F78C-4DCF-B449-D9A9A52FB5F0}"
EndProject
Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "LibProtodec", "LibProtodec\LibProtodec.csproj", "{5F6DAD82-D9AD-4CE5-86E6-D20C9F059A4D}"
EndProject EndProject
Global Global
GlobalSection(SolutionConfigurationPlatforms) = preSolution GlobalSection(SolutionConfigurationPlatforms) = preSolution
@ -15,6 +17,10 @@ Global
{A5493BF4-F78C-4DCF-B449-D9A9A52FB5F0}.Debug|Any CPU.Build.0 = Debug|Any CPU {A5493BF4-F78C-4DCF-B449-D9A9A52FB5F0}.Debug|Any CPU.Build.0 = Debug|Any CPU
{A5493BF4-F78C-4DCF-B449-D9A9A52FB5F0}.Release|Any CPU.ActiveCfg = Release|Any CPU {A5493BF4-F78C-4DCF-B449-D9A9A52FB5F0}.Release|Any CPU.ActiveCfg = Release|Any CPU
{A5493BF4-F78C-4DCF-B449-D9A9A52FB5F0}.Release|Any CPU.Build.0 = Release|Any CPU {A5493BF4-F78C-4DCF-B449-D9A9A52FB5F0}.Release|Any CPU.Build.0 = Release|Any CPU
{5F6DAD82-D9AD-4CE5-86E6-D20C9F059A4D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
{5F6DAD82-D9AD-4CE5-86E6-D20C9F059A4D}.Debug|Any CPU.Build.0 = Debug|Any CPU
{5F6DAD82-D9AD-4CE5-86E6-D20C9F059A4D}.Release|Any CPU.ActiveCfg = Release|Any CPU
{5F6DAD82-D9AD-4CE5-86E6-D20C9F059A4D}.Release|Any CPU.Build.0 = Release|Any CPU
EndGlobalSection EndGlobalSection
GlobalSection(SolutionProperties) = preSolution GlobalSection(SolutionProperties) = preSolution
HideSolutionNode = FALSE HideSolutionNode = FALSE

60
protodec/Program.cs Normal file
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@ -0,0 +1,60 @@
using System;
using System.CodeDom.Compiler;
using System.IO;
using System.Linq;
using LibProtodec;
const string indent = " ";
const string help = """
Usage: protodec(.exe) <target_assembly_dir> <out_path> [target_assembly_name] [options]
Arguments:
target_assembly_dir A directory of assemblies to be loaded.
out_path An existing directory to output into individual files, otherwise output to a single file.
target_assembly_name The name of an assembly to parse. If omitted, all assemblies in the target_assembly_dir will be parsed.
Options:
--skip_enums Skip parsing enums and replace references to them with int32.
""";
if (args.Length < 2)
{
Console.WriteLine(help);
return;
}
string? assemblyName = null;
if (args.Length > 2 && !args[2].StartsWith('-'))
{
assemblyName = args[2];
}
string assemblyDir = args[0];
string outPath = Path.GetFullPath(args[1]);
bool skipEnums = args.Contains("--skip_enums");
using AssemblyInspector inspector = new(assemblyDir, assemblyName);
Protodec protodec = new();
foreach (Type message in inspector.GetProtobufMessageTypes())
{
protodec.ParseMessage(message, skipEnums);
}
if (Directory.Exists(outPath))
{
foreach (Protobuf proto in protodec.Protobufs.Values)
{
string protoPath = Path.Join(outPath, proto.Name + ".proto");
using StreamWriter streamWriter = new(protoPath);
using IndentedTextWriter indentWriter = new(streamWriter, indent);
proto.WriteFileTo(indentWriter);
}
}
else
{
using StreamWriter streamWriter = new(outPath);
using IndentedTextWriter indentWriter = new(streamWriter, indent);
protodec.WriteAllTo(indentWriter);
}

15
protodec/protodec.csproj Normal file
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@ -0,0 +1,15 @@
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<LangVersion>11</LangVersion>
<Nullable>enable</Nullable>
<OutputType>Exe</OutputType>
<RuntimeIdentifiers>win-x64;linux-x64</RuntimeIdentifiers>
<TargetFramework>net7.0</TargetFramework>
</PropertyGroup>
<ItemGroup>
<ProjectReference Include="..\LibProtodec\LibProtodec.csproj" />
</ItemGroup>
</Project>