Avoid infinite recursion if (broken) class loader triggers a load of a class currently being finished.

3 files changed, 61 insertions, 38 deletions

diff --git a/runtime/ClassFile.cs b/runtime/ClassFile.cs
index 11f4c723..1bccbbbe 100644
--- a/runtime/ClassFile.cs
+++ b/runtime/ClassFile.cs
@@ -959,7 +959,7 @@ namespace IKVM.Internal
 			}
 		}
 
-		internal void Link(TypeWrapper thisType)
+		internal void Link(TypeWrapper thisType, LoadMode mode)
 		{
 			// this is not just an optimization, it's required for anonymous classes to be able to refer to themselves
 			((ConstantPoolItemClass)constantpool[this_class]).LinkSelf(thisType);
@@ -967,7 +967,7 @@ namespace IKVM.Internal
 			{
 				if(constantpool[i] != null)
 				{
-					constantpool[i].Link(thisType);
+					constantpool[i].Link(thisType, mode);
 				}
 			}
 		}
@@ -1424,7 +1424,7 @@ namespace IKVM.Internal
 			{
 			}
 
-			internal virtual void Link(TypeWrapper thisType)
+			internal virtual void Link(TypeWrapper thisType, LoadMode mode)
 			{
 			}
 
@@ -1562,11 +1562,11 @@ namespace IKVM.Internal
 				this.typeWrapper = thisType;
 			}
 
-			internal override void Link(TypeWrapper thisType)
+			internal override void Link(TypeWrapper thisType, LoadMode mode)
 			{
 				if(typeWrapper == VerifierTypeWrapper.Null)
 				{
-					TypeWrapper tw = thisType.GetClassLoader().LoadClass(name, LoadMode.Link | LoadMode.WarnClassNotFound);
+					TypeWrapper tw = thisType.GetClassLoader().LoadClass(name, mode | LoadMode.WarnClassNotFound);
 #if !STATIC_COMPILER && !FIRST_PASS
 					if(!tw.IsUnloadable)
 					{
@@ -1677,9 +1677,9 @@ namespace IKVM.Internal
 				clazz.MarkLinkRequired();
 			}
 
-			internal override void Link(TypeWrapper thisType)
+			internal override void Link(TypeWrapper thisType, LoadMode mode)
 			{
-				clazz.Link(thisType);
+				clazz.Link(thisType, mode);
 			}
 
 			internal string Name
@@ -1740,9 +1740,9 @@ namespace IKVM.Internal
 				return fieldTypeWrapper;
 			}
 
-			internal override void Link(TypeWrapper thisType)
+			internal override void Link(TypeWrapper thisType, LoadMode mode)
 			{
-				base.Link(thisType);
+				base.Link(thisType, mode);
 				lock(this)
 				{
 					if(fieldTypeWrapper != null)
@@ -1761,11 +1761,11 @@ namespace IKVM.Internal
 					fw = wrapper.GetFieldWrapper(Name, Signature);
 					if(fw != null)
 					{
-						fw.Link();
+						fw.Link(mode);
 					}
 				}
 				ClassLoaderWrapper classLoader = thisType.GetClassLoader();
-				TypeWrapper fld = classLoader.FieldTypeWrapperFromSigNoThrow(this.Signature);
+				TypeWrapper fld = classLoader.FieldTypeWrapperFromSig(this.Signature, mode);
 				lock(this)
 				{
 					if(fieldTypeWrapper == null)
@@ -1817,9 +1817,9 @@ namespace IKVM.Internal
 				}
 			}
 
-			internal override void Link(TypeWrapper thisType)
+			internal override void Link(TypeWrapper thisType, LoadMode mode)
 			{
-				base.Link(thisType);
+				base.Link(thisType, mode);
 				lock(this)
 				{
 					if(argTypeWrappers != null)
@@ -1828,8 +1828,8 @@ namespace IKVM.Internal
 					}
 				}
 				ClassLoaderWrapper classLoader = thisType.GetClassLoader();
-				TypeWrapper[] args = classLoader.ArgTypeWrapperListFromSigNoThrow(this.Signature);
-				TypeWrapper ret = classLoader.RetTypeWrapperFromSigNoThrow(this.Signature);
+				TypeWrapper[] args = classLoader.ArgTypeWrapperListFromSig(this.Signature, mode);
+				TypeWrapper ret = classLoader.RetTypeWrapperFromSig(this.Signature, mode);
 				lock(this)
 				{
 					if(argTypeWrappers == null)
@@ -1872,16 +1872,16 @@ namespace IKVM.Internal
 			{
 			}
 
-			internal override void Link(TypeWrapper thisType)
+			internal override void Link(TypeWrapper thisType, LoadMode mode)
 			{
-				base.Link(thisType);
+				base.Link(thisType, mode);
 				TypeWrapper wrapper = GetClassType();
 				if(wrapper != null && !wrapper.IsUnloadable)
 				{
 					method = wrapper.GetMethodWrapper(Name, Signature, !ReferenceEquals(Name, StringConstants.INIT));
 					if(method != null)
 					{
-						method.Link();
+						method.Link(mode);
 					}
 					if(Name != StringConstants.INIT
 						&& !thisType.IsInterface
@@ -1892,7 +1892,7 @@ namespace IKVM.Internal
 						invokespecialMethod = thisType.BaseTypeWrapper.GetMethodWrapper(Name, Signature, true);
 						if(invokespecialMethod != null)
 						{
-							invokespecialMethod.Link();
+							invokespecialMethod.Link(mode);
 						}
 					}
 				}
@@ -1905,9 +1905,9 @@ namespace IKVM.Internal
 			{
 			}
 
-			internal override void Link(TypeWrapper thisType)
+			internal override void Link(TypeWrapper thisType, LoadMode mode)
 			{
-				base.Link(thisType);
+				base.Link(thisType, mode);
 				TypeWrapper wrapper = GetClassType();
 				if(wrapper != null)
 				{
@@ -1922,7 +1922,7 @@ namespace IKVM.Internal
 					}
 					if(method != null)
 					{
-						method.Link();
+						method.Link(mode);
 					}
 				}
 			}
@@ -2117,9 +2117,9 @@ namespace IKVM.Internal
 				return cpi.GetClassType();
 			}
 
-			internal override void Link(TypeWrapper thisType)
+			internal override void Link(TypeWrapper thisType, LoadMode mode)
 			{
-				cpi.Link(thisType);
+				cpi.Link(thisType, mode);
 			}
 
 			internal override ConstantType GetConstantType()
@@ -2150,7 +2150,7 @@ namespace IKVM.Internal
 				this.descriptor = String.Intern(descriptor.Replace('/', '.'));
 			}
 
-			internal override void Link(TypeWrapper thisType)
+			internal override void Link(TypeWrapper thisType, LoadMode mode)
 			{
 				lock (this)
 				{
@@ -2160,8 +2160,8 @@ namespace IKVM.Internal
 					}
 				}
 				ClassLoaderWrapper classLoader = thisType.GetClassLoader();
-				TypeWrapper[] args = classLoader.ArgTypeWrapperListFromSigNoThrow(descriptor);
-				TypeWrapper ret = classLoader.RetTypeWrapperFromSigNoThrow(descriptor);
+				TypeWrapper[] args = classLoader.ArgTypeWrapperListFromSig(descriptor, mode);
+				TypeWrapper ret = classLoader.RetTypeWrapperFromSig(descriptor, mode);
 				lock (this)
 				{
 					if (argTypeWrappers == null)
@@ -2220,7 +2220,7 @@ namespace IKVM.Internal
 				descriptor = String.Intern(classFile.GetConstantPoolUtf8String(utf8_cp, name_and_type.descriptor_index).Replace('/', '.'));
 			}
 
-			internal override void Link(TypeWrapper thisType)
+			internal override void Link(TypeWrapper thisType, LoadMode mode)
 			{
 				lock (this)
 				{
@@ -2230,8 +2230,8 @@ namespace IKVM.Internal
 					}
 				}
 				ClassLoaderWrapper classLoader = thisType.GetClassLoader();
-				TypeWrapper[] args = classLoader.ArgTypeWrapperListFromSigNoThrow(descriptor);
-				TypeWrapper ret = classLoader.RetTypeWrapperFromSigNoThrow(descriptor);
+				TypeWrapper[] args = classLoader.ArgTypeWrapperListFromSig(descriptor, mode);
+				TypeWrapper ret = classLoader.RetTypeWrapperFromSig(descriptor, mode);
 				lock (this)
 				{
 					if (argTypeWrappers == null)
diff --git a/runtime/DynamicTypeWrapper.cs b/runtime/DynamicTypeWrapper.cs
index be8a410f..1fe5bf8f 100644
--- a/runtime/DynamicTypeWrapper.cs
+++ b/runtime/DynamicTypeWrapper.cs
@@ -478,6 +478,7 @@ namespace IKVM.Internal
 			private bool finishInProgress;
 			private MethodBuilder clinitMethod;
 			private MethodBuilder finalizeMethod;
+			private int recursionCount;
 #if STATIC_COMPILER
 			private DynamicTypeWrapper enclosingClassWrapper;
 			private AnnotationBuilder annotationBuilder;
@@ -1711,14 +1712,26 @@ namespace IKVM.Internal
 				// make sure all classes are loaded, before we start finishing the type. During finishing, we
 				// may not run any Java code, because that might result in a request to finish the type that we
 				// are in the process of finishing, and this would be a problem.
-				classFile.Link(wrapper);
-				for (int i = 0; i < fields.Length; i++)
+				// Prevent infinity recursion for broken class loaders by keeping a recursion count and falling
+				// back to late binding if we recurse more than twice.
+				LoadMode mode = System.Threading.Interlocked.Increment(ref recursionCount) > 2
+					? LoadMode.ReturnUnloadable
+					: LoadMode.Link;
+				try
 				{
-					fields[i].Link();
+					classFile.Link(wrapper, mode);
+					for (int i = 0; i < fields.Length; i++)
+					{
+						fields[i].Link(mode);
+					}
+					for (int i = 0; i < methods.Length; i++)
+					{
+						methods[i].Link(mode);
+					}
 				}
-				for (int i = 0; i < methods.Length; i++)
+				finally
 				{
-					methods[i].Link();
+					System.Threading.Interlocked.Decrement(ref recursionCount);
 				}
 				// this is the correct lock, FinishCore doesn't call any user code and mutates global state,
 				// so it needs to be protected by a lock.
diff --git a/runtime/MemberWrapper.cs b/runtime/MemberWrapper.cs
index 420a2dcc..53c1d66a 100644
--- a/runtime/MemberWrapper.cs
+++ b/runtime/MemberWrapper.cs
@@ -589,6 +589,11 @@ namespace IKVM.Internal
 
 		internal void Link()
 		{
+			Link(LoadMode.Link);
+		}
+
+		internal void Link(LoadMode mode)
+		{
 			lock(this)
 			{
 				if(parameterTypeWrappers != null)
@@ -597,8 +602,8 @@ namespace IKVM.Internal
 				}
 			}
 			ClassLoaderWrapper loader = this.DeclaringType.GetClassLoader();
-			TypeWrapper ret = loader.RetTypeWrapperFromSigNoThrow(Signature);
-			TypeWrapper[] parameters = loader.ArgTypeWrapperListFromSigNoThrow(Signature);
+			TypeWrapper ret = loader.RetTypeWrapperFromSig(Signature, mode);
+			TypeWrapper[] parameters = loader.ArgTypeWrapperListFromSig(Signature, mode);
 			lock(this)
 			{
 				try
@@ -1462,6 +1467,11 @@ namespace IKVM.Internal
 
 		internal void Link()
 		{
+			Link(LoadMode.Link);
+		}
+
+		internal void Link(LoadMode mode)
+		{
 			lock(this)
 			{
 				if(fieldType != null)
@@ -1469,7 +1479,7 @@ namespace IKVM.Internal
 					return;
 				}
 			}
-			TypeWrapper fld = this.DeclaringType.GetClassLoader().FieldTypeWrapperFromSigNoThrow(Signature);
+			TypeWrapper fld = this.DeclaringType.GetClassLoader().FieldTypeWrapperFromSig(Signature, mode);
 			lock(this)
 			{
 				try