diff options
Diffstat (limited to 'src/StardewModdingAPI/Framework/ModLoading/AssemblyLoader.cs')
| -rw-r--r-- | src/StardewModdingAPI/Framework/ModLoading/AssemblyLoader.cs | 317 |
1 files changed, 317 insertions, 0 deletions
diff --git a/src/StardewModdingAPI/Framework/ModLoading/AssemblyLoader.cs b/src/StardewModdingAPI/Framework/ModLoading/AssemblyLoader.cs new file mode 100644 index 00000000..32988f97 --- /dev/null +++ b/src/StardewModdingAPI/Framework/ModLoading/AssemblyLoader.cs @@ -0,0 +1,317 @@ +using System; +using System.Collections.Generic; +using System.IO; +using System.Linq; +using System.Reflection; +using Mono.Cecil; +using Mono.Cecil.Cil; +using StardewModdingAPI.Framework.Exceptions; +using StardewModdingAPI.Metadata; + +namespace StardewModdingAPI.Framework.ModLoading +{ + /// <summary>Preprocesses and loads mod assemblies.</summary> + internal class AssemblyLoader + { + /********* + ** Properties + *********/ + /// <summary>Metadata for mapping assemblies to the current platform.</summary> + private readonly PlatformAssemblyMap AssemblyMap; + + /// <summary>A type => assembly lookup for types which should be rewritten.</summary> + private readonly IDictionary<string, Assembly> TypeAssemblies; + + /// <summary>Encapsulates monitoring and logging.</summary> + private readonly IMonitor Monitor; + + + /********* + ** Public methods + *********/ + /// <summary>Construct an instance.</summary> + /// <param name="targetPlatform">The current game platform.</param> + /// <param name="monitor">Encapsulates monitoring and logging.</param> + public AssemblyLoader(Platform targetPlatform, IMonitor monitor) + { + this.Monitor = monitor; + this.AssemblyMap = Constants.GetAssemblyMap(targetPlatform); + + // generate type => assembly lookup for types which should be rewritten + this.TypeAssemblies = new Dictionary<string, Assembly>(); + foreach (Assembly assembly in this.AssemblyMap.Targets) + { + ModuleDefinition module = this.AssemblyMap.TargetModules[assembly]; + foreach (TypeDefinition type in module.GetTypes()) + { + if (!type.IsPublic) + continue; // no need to rewrite + if (type.Namespace.Contains("<")) + continue; // ignore assembly metadata + this.TypeAssemblies[type.FullName] = assembly; + } + } + } + + /// <summary>Preprocess and load an assembly.</summary> + /// <param name="mod">The mod for which the assembly is being loaded.</param> + /// <param name="assemblyPath">The assembly file path.</param> + /// <param name="assumeCompatible">Assume the mod is compatible, even if incompatible code is detected.</param> + /// <returns>Returns the rewrite metadata for the preprocessed assembly.</returns> + /// <exception cref="IncompatibleInstructionException">An incompatible CIL instruction was found while rewriting the assembly.</exception> + public Assembly Load(IModMetadata mod, string assemblyPath, bool assumeCompatible) + { + // get referenced local assemblies + AssemblyParseResult[] assemblies; + { + AssemblyDefinitionResolver resolver = new AssemblyDefinitionResolver(); + HashSet<string> visitedAssemblyNames = new HashSet<string>(AppDomain.CurrentDomain.GetAssemblies().Select(p => p.GetName().Name)); // don't try loading assemblies that are already loaded + assemblies = this.GetReferencedLocalAssemblies(new FileInfo(assemblyPath), visitedAssemblyNames, resolver).ToArray(); + } + + // validate load + if (!assemblies.Any() || assemblies[0].Status == AssemblyLoadStatus.Failed) + { + throw new SAssemblyLoadFailedException(!File.Exists(assemblyPath) + ? $"Could not load '{assemblyPath}' because it doesn't exist." + : $"Could not load '{assemblyPath}'." + ); + } + if (assemblies.Last().Status == AssemblyLoadStatus.AlreadyLoaded) // mod assembly is last in dependency order + throw new SAssemblyLoadFailedException($"Could not load '{assemblyPath}' because it was already loaded. Do you have two copies of this mod?"); + + // rewrite & load assemblies in leaf-to-root order + bool oneAssembly = assemblies.Length == 1; + Assembly lastAssembly = null; + HashSet<string> loggedMessages = new HashSet<string>(); + foreach (AssemblyParseResult assembly in assemblies) + { + if (assembly.Status == AssemblyLoadStatus.AlreadyLoaded) + continue; + + bool changed = this.RewriteAssembly(mod, assembly.Definition, assumeCompatible, loggedMessages, logPrefix: " "); + if (changed) + { + if (!oneAssembly) + this.Monitor.Log($" Loading {assembly.File.Name} (rewritten in memory)...", LogLevel.Trace); + using (MemoryStream outStream = new MemoryStream()) + { + assembly.Definition.Write(outStream); + byte[] bytes = outStream.ToArray(); + lastAssembly = Assembly.Load(bytes); + } + } + else + { + if (!oneAssembly) + this.Monitor.Log($" Loading {assembly.File.Name}...", LogLevel.Trace); + lastAssembly = Assembly.UnsafeLoadFrom(assembly.File.FullName); + } + } + + // last assembly loaded is the root + return lastAssembly; + } + + /// <summary>Resolve an assembly by its name.</summary> + /// <param name="name">The assembly name.</param> + /// <remarks> + /// This implementation returns the first loaded assembly which matches the short form of + /// the assembly name, to resolve assembly resolution issues when rewriting + /// assemblies (especially with Mono). Since this is meant to be called on <see cref="AppDomain.AssemblyResolve"/>, + /// the implicit assumption is that loading the exact assembly failed. + /// </remarks> + public Assembly ResolveAssembly(string name) + { + string shortName = name.Split(new[] { ',' }, 2).First(); // get simple name (without version and culture) + return AppDomain.CurrentDomain + .GetAssemblies() + .FirstOrDefault(p => p.GetName().Name == shortName); + } + + + /********* + ** Private methods + *********/ + /**** + ** Assembly parsing + ****/ + /// <summary>Get a list of referenced local assemblies starting from the mod assembly, ordered from leaf to root.</summary> + /// <param name="file">The assembly file to load.</param> + /// <param name="visitedAssemblyNames">The assembly names that should be skipped.</param> + /// <param name="assemblyResolver">A resolver which resolves references to known assemblies.</param> + /// <returns>Returns the rewrite metadata for the preprocessed assembly.</returns> + private IEnumerable<AssemblyParseResult> GetReferencedLocalAssemblies(FileInfo file, HashSet<string> visitedAssemblyNames, IAssemblyResolver assemblyResolver) + { + // validate + if (file.Directory == null) + throw new InvalidOperationException($"Could not get directory from file path '{file.FullName}'."); + if (!file.Exists) + yield break; // not a local assembly + + // read assembly + byte[] assemblyBytes = File.ReadAllBytes(file.FullName); + AssemblyDefinition assembly; + using (Stream readStream = new MemoryStream(assemblyBytes)) + assembly = AssemblyDefinition.ReadAssembly(readStream, new ReaderParameters(ReadingMode.Deferred) { AssemblyResolver = assemblyResolver }); + + // skip if already visited + if (visitedAssemblyNames.Contains(assembly.Name.Name)) + yield return new AssemblyParseResult(file, null, AssemblyLoadStatus.AlreadyLoaded); + visitedAssemblyNames.Add(assembly.Name.Name); + + // yield referenced assemblies + foreach (AssemblyNameReference dependency in assembly.MainModule.AssemblyReferences) + { + FileInfo dependencyFile = new FileInfo(Path.Combine(file.Directory.FullName, $"{dependency.Name}.dll")); + foreach (AssemblyParseResult result in this.GetReferencedLocalAssemblies(dependencyFile, visitedAssemblyNames, assemblyResolver)) + yield return result; + } + + // yield assembly + yield return new AssemblyParseResult(file, assembly, AssemblyLoadStatus.Okay); + } + + /**** + ** Assembly rewriting + ****/ + /// <summary>Rewrite the types referenced by an assembly.</summary> + /// <param name="mod">The mod for which the assembly is being loaded.</param> + /// <param name="assembly">The assembly to rewrite.</param> + /// <param name="assumeCompatible">Assume the mod is compatible, even if incompatible code is detected.</param> + /// <param name="loggedMessages">The messages that have already been logged for this mod.</param> + /// <param name="logPrefix">A string to prefix to log messages.</param> + /// <returns>Returns whether the assembly was modified.</returns> + /// <exception cref="IncompatibleInstructionException">An incompatible CIL instruction was found while rewriting the assembly.</exception> + private bool RewriteAssembly(IModMetadata mod, AssemblyDefinition assembly, bool assumeCompatible, HashSet<string> loggedMessages, string logPrefix) + { + ModuleDefinition module = assembly.MainModule; + string filename = $"{assembly.Name.Name}.dll"; + + // swap assembly references if needed (e.g. XNA => MonoGame) + bool platformChanged = false; + for (int i = 0; i < module.AssemblyReferences.Count; i++) + { + // remove old assembly reference + if (this.AssemblyMap.RemoveNames.Any(name => module.AssemblyReferences[i].Name == name)) + { + this.Monitor.LogOnce(loggedMessages, $"{logPrefix}Rewriting {filename} for OS..."); + platformChanged = true; + module.AssemblyReferences.RemoveAt(i); + i--; + } + } + if (platformChanged) + { + // add target assembly references + foreach (AssemblyNameReference target in this.AssemblyMap.TargetReferences.Values) + module.AssemblyReferences.Add(target); + + // rewrite type scopes to use target assemblies + IEnumerable<TypeReference> typeReferences = module.GetTypeReferences().OrderBy(p => p.FullName); + foreach (TypeReference type in typeReferences) + this.ChangeTypeScope(type); + } + + // find (and optionally rewrite) incompatible instructions + bool anyRewritten = false; + IInstructionHandler[] handlers = new InstructionMetadata().GetHandlers().ToArray(); + foreach (MethodDefinition method in this.GetMethods(module)) + { + // check method definition + foreach (IInstructionHandler handler in handlers) + { + InstructionHandleResult result = handler.Handle(module, method, this.AssemblyMap, platformChanged); + this.ProcessInstructionHandleResult(mod, handler, result, loggedMessages, logPrefix, assumeCompatible, filename); + if (result == InstructionHandleResult.Rewritten) + anyRewritten = true; + } + + // check CIL instructions + ILProcessor cil = method.Body.GetILProcessor(); + foreach (Instruction instruction in cil.Body.Instructions.ToArray()) + { + foreach (IInstructionHandler handler in handlers) + { + InstructionHandleResult result = handler.Handle(module, cil, instruction, this.AssemblyMap, platformChanged); + this.ProcessInstructionHandleResult(mod, handler, result, loggedMessages, logPrefix, assumeCompatible, filename); + if (result == InstructionHandleResult.Rewritten) + anyRewritten = true; + } + } + } + + return platformChanged || anyRewritten; + } + + /// <summary>Process the result from an instruction handler.</summary> + /// <param name="mod">The mod being analysed.</param> + /// <param name="handler">The instruction handler.</param> + /// <param name="result">The result returned by the handler.</param> + /// <param name="loggedMessages">The messages already logged for the current mod.</param> + /// <param name="assumeCompatible">Assume the mod is compatible, even if incompatible code is detected.</param> + /// <param name="logPrefix">A string to prefix to log messages.</param> + /// <param name="filename">The assembly filename for log messages.</param> + private void ProcessInstructionHandleResult(IModMetadata mod, IInstructionHandler handler, InstructionHandleResult result, HashSet<string> loggedMessages, string logPrefix, bool assumeCompatible, string filename) + { + switch (result) + { + case InstructionHandleResult.Rewritten: + this.Monitor.LogOnce(loggedMessages, $"{logPrefix}Rewrote {filename} to fix {handler.NounPhrase}..."); + break; + + case InstructionHandleResult.NotCompatible: + if (!assumeCompatible) + throw new IncompatibleInstructionException(handler.NounPhrase, $"Found an incompatible CIL instruction ({handler.NounPhrase}) while loading assembly {filename}."); + this.Monitor.LogOnce(loggedMessages, $"{logPrefix}Found an incompatible CIL instruction ({handler.NounPhrase}) while loading assembly {filename}, but SMAPI is configured to allow it anyway. The mod may crash or behave unexpectedly.", LogLevel.Warn); + break; + + case InstructionHandleResult.DetectedGamePatch: + this.Monitor.LogOnce(loggedMessages, $"{logPrefix}Detected game patcher ({handler.NounPhrase}) in assembly {filename}."); + this.Monitor.LogOnce(loggedMessages, $"{mod.DisplayName} patches the game, which may impact game stability. If you encounter problems, try removing this mod first.", LogLevel.Warn); + break; + + case InstructionHandleResult.DetectedSaveSerialiser: + this.Monitor.LogOnce(loggedMessages, $"{logPrefix}Detected possible save serialiser change ({handler.NounPhrase}) in assembly {filename}."); + this.Monitor.LogOnce(loggedMessages, $"{mod.DisplayName} seems to change the save serialiser. It may change your saves in such a way that they won't work without this mod in the future.", LogLevel.Warn); + break; + + case InstructionHandleResult.None: + break; + + default: + throw new NotSupportedException($"Unrecognised instruction handler result '{result}'."); + } + } + + /// <summary>Get the correct reference to use for compatibility with the current platform.</summary> + /// <param name="type">The type reference to rewrite.</param> + private void ChangeTypeScope(TypeReference type) + { + // check skip conditions + if (type == null || type.FullName.StartsWith("System.")) + return; + + // get assembly + if (!this.TypeAssemblies.TryGetValue(type.FullName, out Assembly assembly)) + return; + + // replace scope + AssemblyNameReference assemblyRef = this.AssemblyMap.TargetReferences[assembly]; + type.Scope = assemblyRef; + } + + /// <summary>Get all methods in a module.</summary> + /// <param name="module">The module to search.</param> + private IEnumerable<MethodDefinition> GetMethods(ModuleDefinition module) + { + return ( + from type in module.GetTypes() + where type.HasMethods + from method in type.Methods + where method.HasBody + select method + ); + } + } +} |