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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Collections;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Runtime.Serialization;
namespace System
{
public partial class Exception : ISerializable
{
partial void RestoreRemoteStackTrace(SerializationInfo info, StreamingContext context)
{
// Get the WatsonBuckets that were serialized - this is particularly
// done to support exceptions going across AD transitions.
//
// We use the no throw version since we could be deserializing a pre-V4
// exception object that may not have this entry. In such a case, we would
// get null.
_watsonBuckets = (byte[]?)info.GetValueNoThrow("WatsonBuckets", typeof(byte[])); // Do not rename (binary serialization)
// If we are constructing a new exception after a cross-appdomain call...
#pragma warning disable SYSLIB0050 // StreamingContextStates is obsolete
if (context.State == StreamingContextStates.CrossAppDomain)
#pragma warning restore SYSLIB0050
{
// ...this new exception may get thrown. It is logically a re-throw, but
// physically a brand-new exception. Since the stack trace is cleared
// on a new exception, the "_remoteStackTraceString" is provided to
// effectively import a stack trace from a "remote" exception. So,
// move the _stackTraceString into the _remoteStackTraceString. Note
// that if there is an existing _remoteStackTraceString, it will be
// preserved at the head of the new string, so everything works as
// expected.
// Even if this exception is NOT thrown, things will still work as expected
// because the StackTrace property returns the concatenation of the
// _remoteStackTraceString and the _stackTraceString.
_remoteStackTraceString += _stackTraceString;
_stackTraceString = null;
}
}
private IDictionary CreateDataContainer()
{
if (IsImmutableAgileException(this))
return new EmptyReadOnlyDictionaryInternal();
else
return new ListDictionaryInternal();
}
[MethodImpl(MethodImplOptions.InternalCall)]
private static extern bool IsImmutableAgileException(Exception e);
[MethodImpl(MethodImplOptions.InternalCall)]
private static extern IRuntimeMethodInfo GetMethodFromStackTrace(object stackTrace);
private MethodBase? GetExceptionMethodFromStackTrace()
{
Debug.Assert(_stackTrace != null, "_stackTrace shouldn't be null when this method is called");
IRuntimeMethodInfo method = GetMethodFromStackTrace(_stackTrace!);
// Under certain race conditions when exceptions are re-used, this can be null
if (method == null)
return null;
return RuntimeType.GetMethodBase(method);
}
public MethodBase? TargetSite
{
[RequiresUnreferencedCode("Metadata for the method might be incomplete or removed")]
get
{
if (_exceptionMethod != null)
{
return _exceptionMethod;
}
if (_stackTrace == null)
{
return null;
}
_exceptionMethod = GetExceptionMethodFromStackTrace();
return _exceptionMethod;
}
}
// This method will clear the _stackTrace of the exception object upon deserialization
// to ensure that references from another AD/Process dont get accidentally used.
[OnDeserialized]
private void OnDeserialized(StreamingContext context)
{
_stackTrace = null;
// We wont serialize or deserialize the IP for Watson bucketing since
// we dont know where the deserialized object will be used in.
// Using it across process or an AppDomain could be invalid and result
// in AV in the runtime.
//
// Hence, we set it to zero when deserialization takes place.
_ipForWatsonBuckets = UIntPtr.Zero;
}
// This is used by the runtime when re-throwing a managed exception. It will
// copy the stack trace to _remoteStackTraceString.
internal void InternalPreserveStackTrace()
{
// Make sure that the _source field is initialized if Source is not overridden.
// We want it to contain the original faulting point.
_ = Source;
string? tmpStackTraceString = StackTrace;
if (!string.IsNullOrEmpty(tmpStackTraceString))
{
_remoteStackTraceString = tmpStackTraceString + Environment.NewLineConst;
}
_stackTrace = null;
_stackTraceString = null;
}
[MethodImpl(MethodImplOptions.InternalCall)]
private static extern void PrepareForForeignExceptionRaise();
[MethodImpl(MethodImplOptions.InternalCall)]
private static extern void GetStackTracesDeepCopy(Exception exception, out byte[]? currentStackTrace, out object[]? dynamicMethodArray);
[MethodImpl(MethodImplOptions.InternalCall)]
internal static extern void SaveStackTracesFromDeepCopy(Exception exception, byte[]? currentStackTrace, object[]? dynamicMethodArray);
[MethodImpl(MethodImplOptions.InternalCall)]
internal static extern uint GetExceptionCount();
// This is invoked by ExceptionDispatchInfo.Throw to restore the exception stack trace, corresponding to the original throw of the
// exception, just before the exception is "rethrown".
internal void RestoreDispatchState(in DispatchState dispatchState)
{
// Restore only for non-preallocated exceptions
if (!IsImmutableAgileException(this))
{
// When restoring back the fields, we again create a copy and set reference to them
// in the exception object. This will ensure that when this exception is thrown and these
// fields are modified, then EDI's references remain intact.
//
byte[]? stackTraceCopy = (byte[]?)dispatchState.StackTrace?.Clone();
object[]? dynamicMethodsCopy = (object[]?)dispatchState.DynamicMethods?.Clone();
// Watson buckets and remoteStackTraceString fields are captured and restored without any locks. It is possible for them to
// get out of sync without violating overall integrity of the system.
_watsonBuckets = dispatchState.WatsonBuckets;
_ipForWatsonBuckets = dispatchState.IpForWatsonBuckets;
_remoteStackTraceString = dispatchState.RemoteStackTrace;
// The binary stack trace and references to dynamic methods have to be restored under a lock to guarantee integrity of the system.
SaveStackTracesFromDeepCopy(this, stackTraceCopy, dynamicMethodsCopy);
_stackTraceString = null;
// Marks the TES state to indicate we have restored foreign exception
// dispatch information.
PrepareForForeignExceptionRaise();
}
}
private MethodBase? _exceptionMethod; // Needed for serialization.
internal string? _message;
private IDictionary? _data;
private readonly Exception? _innerException;
private string? _helpURL;
private byte[]? _stackTrace;
private byte[]? _watsonBuckets;
private string? _stackTraceString; // Needed for serialization.
private string? _remoteStackTraceString;
#pragma warning disable CA1823, 414 // Fields are not used from managed.
// _dynamicMethods is an array of System.Resolver objects, used to keep
// DynamicMethodDescs alive for the lifetime of the exception. We do this because
// the _stackTrace field holds MethodDescs, and a DynamicMethodDesc can be destroyed
// unless a System.Resolver object roots it.
private readonly object[]? _dynamicMethods;
private string? _source; // Mainly used by VB.
private UIntPtr _ipForWatsonBuckets; // Used to persist the IP for Watson Bucketing
private readonly IntPtr _xptrs; // Internal EE stuff
private readonly int _xcode = _COMPlusExceptionCode; // Internal EE stuff
#pragma warning restore CA1823, 414
// @MANAGED: HResult is used from within the EE! Rename with care - check VM directory
private int _HResult; // HResult
// See src\inc\corexcep.h's EXCEPTION_COMPLUS definition:
private const int _COMPlusExceptionCode = unchecked((int)0xe0434352); // Win32 exception code for COM+ exceptions
private bool HasBeenThrown => _stackTrace != null;
private object? SerializationWatsonBuckets => _watsonBuckets;
// This piece of infrastructure exists to help avoid deadlocks
// between parts of CoreLib that might throw an exception while
// holding a lock that are also used by CoreLib's ResourceManager
// instance. As a special case of code that may throw while holding
// a lock, we also need to fix our asynchronous exceptions to use
// Win32 resources as well (assuming we ever call a managed
// constructor on instances of them). We should grow this set of
// exception messages as we discover problems, then move the resources
// involved to native code.
internal enum ExceptionMessageKind
{
ThreadAbort = 1,
ThreadInterrupted = 2,
OutOfMemory = 3
}
// See comment on ExceptionMessageKind
internal static string GetMessageFromNativeResources(ExceptionMessageKind kind)
{
string? retMesg = null;
GetMessageFromNativeResources(kind, new StringHandleOnStack(ref retMesg));
return retMesg!;
}
[LibraryImport(RuntimeHelpers.QCall, EntryPoint = "ExceptionNative_GetMessageFromNativeResources")]
private static partial void GetMessageFromNativeResources(ExceptionMessageKind kind, StringHandleOnStack retMesg);
internal readonly struct DispatchState
{
public readonly byte[]? StackTrace;
public readonly object[]? DynamicMethods;
public readonly string? RemoteStackTrace;
public readonly UIntPtr IpForWatsonBuckets;
public readonly byte[]? WatsonBuckets;
public DispatchState(
byte[]? stackTrace,
object[]? dynamicMethods,
string? remoteStackTrace,
UIntPtr ipForWatsonBuckets,
byte[]? watsonBuckets)
{
StackTrace = stackTrace;
DynamicMethods = dynamicMethods;
RemoteStackTrace = remoteStackTrace;
IpForWatsonBuckets = ipForWatsonBuckets;
WatsonBuckets = watsonBuckets;
}
}
internal DispatchState CaptureDispatchState()
{
GetStackTracesDeepCopy(this, out byte[]? stackTrace, out object[]? dynamicMethods);
return new DispatchState(stackTrace, dynamicMethods,
_remoteStackTraceString, _ipForWatsonBuckets, _watsonBuckets);
}
// Returns true if setting the _remoteStackTraceString field is legal, false if not (immutable exception).
// A false return value means the caller should early-exit the operation.
// Can also throw InvalidOperationException if a stack trace is already set or if object has been thrown.
private bool CanSetRemoteStackTrace()
{
// If this is a preallocated singleton exception, silently skip the operation,
// regardless of the value of throwIfHasExistingStack.
if (IsImmutableAgileException(this))
{
return false;
}
// Check to see if the exception already has a stack set in it.
if (_stackTrace != null || _stackTraceString != null || _remoteStackTraceString != null)
{
ThrowHelper.ThrowInvalidOperationException();
}
return true;
}
// used by vm
internal string? GetHelpContext(out uint helpContext)
{
helpContext = 0;
string? helpFile = HelpLink;
int poundPos, digitEnd;
if (helpFile is null || (poundPos = helpFile.LastIndexOf('#')) == -1)
{
return helpFile;
}
for (digitEnd = poundPos + 1; digitEnd < helpFile.Length; digitEnd++)
{
if (char.IsWhiteSpace(helpFile[digitEnd]))
break;
}
if (uint.TryParse(helpFile.AsSpan(poundPos + 1, digitEnd - poundPos - 1), out helpContext))
{
helpFile = helpFile.Substring(0, poundPos);
}
return helpFile;
}
}
}
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