Files
btcpayserver/BTCPayServer/Plugins/Dotnet/Loader/ManagedLoadContext.cs

411 lines
17 KiB
C#

#nullable enable
// Copyright (c) Nate McMaster.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.Loader;
using BTCPayServer.Plugins.Dotnet.Internal;
using BTCPayServer.Plugins.Dotnet.LibraryModel;
namespace BTCPayServer.Plugins.Dotnet.Loader
{
/// <summary>
/// An implementation of <see cref="AssemblyLoadContext" /> which attempts to load managed and native
/// binaries at runtime immitating some of the behaviors of corehost.
/// </summary>
[DebuggerDisplay("'{Name}' ({_mainAssemblyPath})")]
internal class ManagedLoadContext : AssemblyLoadContext
{
private readonly string _basePath;
private readonly string _mainAssemblyPath;
private readonly IReadOnlyDictionary<string, ManagedLibrary> _managedAssemblies;
private readonly IReadOnlyDictionary<string, NativeLibrary> _nativeLibraries;
private readonly IReadOnlyCollection<string> _privateAssemblies;
private readonly ICollection<string> _defaultAssemblies;
private readonly IReadOnlyCollection<string> _additionalProbingPaths;
private readonly bool _preferDefaultLoadContext;
private readonly string[] _resourceRoots;
private readonly bool _loadInMemory;
private readonly bool _lazyLoadReferences;
private readonly List<AssemblyLoadContext> _assemblyLoadContexts = new();
private readonly AssemblyDependencyResolver _dependencyResolver;
private readonly bool _shadowCopyNativeLibraries;
private readonly string _unmanagedDllShadowCopyDirectoryPath;
public ManagedLoadContext(string mainAssemblyPath,
IReadOnlyDictionary<string, ManagedLibrary> managedAssemblies,
IReadOnlyDictionary<string, NativeLibrary> nativeLibraries,
IReadOnlyCollection<string> privateAssemblies,
IReadOnlyCollection<string> defaultAssemblies,
IReadOnlyCollection<string> additionalProbingPaths,
IReadOnlyCollection<string> resourceProbingPaths,
AssemblyLoadContext defaultLoadContext,
bool preferDefaultLoadContext,
bool lazyLoadReferences,
bool isCollectible,
bool loadInMemory,
bool shadowCopyNativeLibraries)
: base(Path.GetFileNameWithoutExtension(mainAssemblyPath), isCollectible)
{
if (resourceProbingPaths == null)
{
throw new ArgumentNullException(nameof(resourceProbingPaths));
}
_mainAssemblyPath = mainAssemblyPath ?? throw new ArgumentNullException(nameof(mainAssemblyPath));
_dependencyResolver = new AssemblyDependencyResolver(mainAssemblyPath);
_basePath = Path.GetDirectoryName(mainAssemblyPath) ?? throw new ArgumentException(nameof(mainAssemblyPath));
_managedAssemblies = managedAssemblies ?? throw new ArgumentNullException(nameof(managedAssemblies));
_privateAssemblies = privateAssemblies ?? throw new ArgumentNullException(nameof(privateAssemblies));
_defaultAssemblies = defaultAssemblies != null ? defaultAssemblies.ToList() : throw new ArgumentNullException(nameof(defaultAssemblies));
_nativeLibraries = nativeLibraries ?? throw new ArgumentNullException(nameof(nativeLibraries));
_additionalProbingPaths = additionalProbingPaths ?? throw new ArgumentNullException(nameof(additionalProbingPaths));
_assemblyLoadContexts.Add(defaultLoadContext);
_preferDefaultLoadContext = preferDefaultLoadContext;
_loadInMemory = loadInMemory;
_lazyLoadReferences = lazyLoadReferences;
_resourceRoots = new[] { _basePath }
.Concat(resourceProbingPaths)
.ToArray();
_shadowCopyNativeLibraries = shadowCopyNativeLibraries;
_unmanagedDllShadowCopyDirectoryPath = Path.Combine(Path.GetTempPath(), Path.GetRandomFileName());
if (shadowCopyNativeLibraries)
{
Unloading += _ => OnUnloaded();
}
}
public void AddAssemblyLoadContexts(IEnumerable<AssemblyLoadContext> assemblyLoadContexts) => _assemblyLoadContexts.AddRange(assemblyLoadContexts);
/// <summary>
/// Load an assembly.
/// </summary>
/// <param name="assemblyName"></param>
/// <returns></returns>
protected override Assembly? Load(AssemblyName assemblyName)
{
if (assemblyName.Name == null)
{
// not sure how to handle this case. It's technically possible.
return null;
}
if ((_preferDefaultLoadContext || _defaultAssemblies.Contains(assemblyName.Name)) && !_privateAssemblies.Contains(assemblyName.Name))
{
var name = new AssemblyName(assemblyName.Name);
var assembly = _assemblyLoadContexts.Select(p => TryLoadFromAssemblyName(p, name)).FirstOrDefault(a => a is not null);
if (assembly is not null)
return assembly;
}
var resolvedPath = _dependencyResolver.ResolveAssemblyToPath(assemblyName);
if (!string.IsNullOrEmpty(resolvedPath) && File.Exists(resolvedPath))
{
return LoadAssemblyFromFilePath(resolvedPath);
}
// Resource assembly binding does not use the TPA. Instead, it probes PLATFORM_RESOURCE_ROOTS (a list of folders)
// for $folder/$culture/$assemblyName.dll
// See https://github.com/dotnet/coreclr/blob/3fca50a36e62a7433d7601d805d38de6baee7951/src/binder/assemblybinder.cpp#L1232-L1290
if (!string.IsNullOrEmpty(assemblyName.CultureName) && !string.Equals("neutral", assemblyName.CultureName))
{
foreach (var resourceRoot in _resourceRoots)
{
var resourcePath = Path.Combine(resourceRoot, assemblyName.CultureName, assemblyName.Name + ".dll");
if (File.Exists(resourcePath))
{
return LoadAssemblyFromFilePath(resourcePath);
}
}
return null;
}
if (_managedAssemblies.TryGetValue(assemblyName.Name, out var library) && library != null)
{
if (SearchForLibrary(library, out var path) && path != null)
{
return LoadAssemblyFromFilePath(path);
}
}
else
{
// if an assembly was not listed in the list of known assemblies,
// fallback to the load context base directory
var dllName = assemblyName.Name + ".dll";
foreach (var probingPath in _additionalProbingPaths.Prepend(_basePath))
{
var localFile = Path.Combine(probingPath, dllName);
if (File.Exists(localFile))
{
return LoadAssemblyFromFilePath(localFile);
}
}
}
return null;
}
private Assembly? TryLoadFromAssemblyName(AssemblyLoadContext context, AssemblyName name)
{
// If default context is preferred, check first for types in the default context unless the dependency has been declared as private
try
{
var defaultAssembly = context.LoadFromAssemblyName(name);
if (defaultAssembly != null)
{
// Add referenced assemblies to the list of default assemblies.
// This is basically lazy loading
if (_lazyLoadReferences)
{
foreach (var reference in defaultAssembly.GetReferencedAssemblies())
{
if (reference.Name != null && !_defaultAssemblies.Contains(reference.Name))
{
_defaultAssemblies.Add(reference.Name);
}
}
}
// Older versions used to return null here such that returned assembly would be resolved from the default ALC.
// However, with the addition of custom default ALCs, the Default ALC may not be the user's chosen ALC when
// this context was built. As such, we simply return the Assembly from the user's chosen default load context.
return defaultAssembly;
}
}
catch
{
// Swallow errors in loading from the default context
}
return null;
}
public Assembly LoadAssemblyFromFilePath(string path)
{
if (!_loadInMemory)
{
return LoadFromAssemblyPath(path);
}
using var file = File.Open(path, FileMode.Open, FileAccess.Read, FileShare.Read);
var pdbPath = Path.ChangeExtension(path, ".pdb");
if (File.Exists(pdbPath))
{
using var pdbFile = File.Open(pdbPath, FileMode.Open, FileAccess.Read, FileShare.Read);
return LoadFromStream(file, pdbFile);
}
return LoadFromStream(file);
}
/// <summary>
/// Loads the unmanaged binary using configured list of native libraries.
/// </summary>
/// <param name="unmanagedDllName"></param>
/// <returns></returns>
protected override IntPtr LoadUnmanagedDll(string unmanagedDllName)
{
var resolvedPath = _dependencyResolver.ResolveUnmanagedDllToPath(unmanagedDllName);
if (!string.IsNullOrEmpty(resolvedPath) && File.Exists(resolvedPath))
{
return LoadUnmanagedDllFromResolvedPath(resolvedPath, normalizePath: false);
}
foreach (var prefix in PlatformInformation.NativeLibraryPrefixes)
{
if (_nativeLibraries.TryGetValue(prefix + unmanagedDllName, out var library))
{
if (SearchForLibrary(library, prefix, out var path) && path != null)
{
return LoadUnmanagedDllFromResolvedPath(path);
}
}
else
{
// coreclr allows code to use [DllImport("sni")] or [DllImport("sni.dll")]
// This library treats the file name without the extension as the lookup name,
// so this loop is necessary to check if the unmanaged name matches a library
// when the file extension has been trimmed.
foreach (var suffix in PlatformInformation.NativeLibraryExtensions)
{
if (!unmanagedDllName.EndsWith(suffix, StringComparison.OrdinalIgnoreCase))
{
continue;
}
// check to see if there is a library entry for the library without the file extension
var trimmedName = unmanagedDllName.Substring(0, unmanagedDllName.Length - suffix.Length);
if (_nativeLibraries.TryGetValue(prefix + trimmedName, out library))
{
if (SearchForLibrary(library, prefix, out var path) && path != null)
{
return LoadUnmanagedDllFromResolvedPath(path);
}
}
else
{
// fallback to native assets which match the file name in the plugin base directory
var prefixSuffixDllName = prefix + unmanagedDllName + suffix;
var prefixDllName = prefix + unmanagedDllName;
foreach (var probingPath in _additionalProbingPaths.Prepend(_basePath))
{
var localFile = Path.Combine(probingPath, prefixSuffixDllName);
if (File.Exists(localFile))
{
return LoadUnmanagedDllFromResolvedPath(localFile);
}
var localFileWithoutSuffix = Path.Combine(probingPath, prefixDllName);
if (File.Exists(localFileWithoutSuffix))
{
return LoadUnmanagedDllFromResolvedPath(localFileWithoutSuffix);
}
}
}
}
}
}
return base.LoadUnmanagedDll(unmanagedDllName);
}
private bool SearchForLibrary(ManagedLibrary library, out string? path)
{
// 1. Check for in _basePath + app local path
var localFile = Path.Combine(_basePath, library.AppLocalPath);
if (File.Exists(localFile))
{
path = localFile;
return true;
}
// 2. Search additional probing paths
foreach (var searchPath in _additionalProbingPaths)
{
var candidate = Path.Combine(searchPath, library.AdditionalProbingPath);
if (File.Exists(candidate))
{
path = candidate;
return true;
}
}
// 3. Search in base path
foreach (var ext in PlatformInformation.ManagedAssemblyExtensions)
{
var local = Path.Combine(_basePath, library.Name.Name + ext);
if (File.Exists(local))
{
path = local;
return true;
}
}
path = null;
return false;
}
private bool SearchForLibrary(NativeLibrary library, string prefix, out string? path)
{
// 1. Search in base path
foreach (var ext in PlatformInformation.NativeLibraryExtensions)
{
var candidate = Path.Combine(_basePath, $"{prefix}{library.Name}{ext}");
if (File.Exists(candidate))
{
path = candidate;
return true;
}
}
// 2. Search in base path + app local (for portable deployments of netcoreapp)
var local = Path.Combine(_basePath, library.AppLocalPath);
if (File.Exists(local))
{
path = local;
return true;
}
// 3. Search additional probing paths
foreach (var searchPath in _additionalProbingPaths)
{
var candidate = Path.Combine(searchPath, library.AdditionalProbingPath);
if (File.Exists(candidate))
{
path = candidate;
return true;
}
}
path = null;
return false;
}
private IntPtr LoadUnmanagedDllFromResolvedPath(string unmanagedDllPath, bool normalizePath = true)
{
if (normalizePath)
{
unmanagedDllPath = Path.GetFullPath(unmanagedDllPath);
}
return _shadowCopyNativeLibraries
? LoadUnmanagedDllFromShadowCopy(unmanagedDllPath)
: LoadUnmanagedDllFromPath(unmanagedDllPath);
}
private IntPtr LoadUnmanagedDllFromShadowCopy(string unmanagedDllPath)
{
var shadowCopyDllPath = CreateShadowCopy(unmanagedDllPath);
return LoadUnmanagedDllFromPath(shadowCopyDllPath);
}
private string CreateShadowCopy(string dllPath)
{
Directory.CreateDirectory(_unmanagedDllShadowCopyDirectoryPath);
var dllFileName = Path.GetFileName(dllPath);
var shadowCopyPath = Path.Combine(_unmanagedDllShadowCopyDirectoryPath, dllFileName);
if (!File.Exists(shadowCopyPath))
{
File.Copy(dllPath, shadowCopyPath);
}
return shadowCopyPath;
}
private void OnUnloaded()
{
if (!_shadowCopyNativeLibraries || !Directory.Exists(_unmanagedDllShadowCopyDirectoryPath))
{
return;
}
// Attempt to delete shadow copies
try
{
Directory.Delete(_unmanagedDllShadowCopyDirectoryPath, recursive: true);
}
catch (Exception)
{
// Files might be locked by host process. Nothing we can do about it, I guess.
}
}
}
}