Question

在.NET 4.6的AppDomain中抛出AccessViolationException（或其他损坏的状态异常）时，如何防止整个应用程序（进程）崩溃？我的目标是在其AppDomain中包装一个第三方库（GdPicture.NET条形码读取器），该库根据IIS故障转储间歇性地使IIS工作进程崩溃。换句话说，我想在自己的应用程序域中隔离第3方库调用，以使它在自身内部失败而无需关闭整个网站。

在下面的示例代码中，如果我不使用HandleProcessCorruptedStateExceptions属性，则无法捕获被抛出在另一个AppDomain（在ClassLibrary1.dll中）中的AccessViolationException（包装在TargetInvocationException中）。如果我装饰了HandleProcessCorruptedStateExceptions（仅适用于第二个AppDomain调用），那么主进程继续运行是否安全还是会变得不稳定？

具有两个项目（控制台应用程序和类库）的Visual Studio解决方案。

using System;
using System.Reflection;
using System.Runtime.ExceptionServices;
using System.Security;

namespace StackOverflowQuestion
{
    class Program
    {
        static void Main(string[] args)
        {
            new Tester().RunTest();
        }
    }

    class Tester
    {
        public void RunTest()
        {
            var myTestAppDomain = AppDomain.CreateDomain("My Test AppDomain");
            var loader = (Loader)myTestAppDomain.CreateInstanceAndUnwrap(typeof(Loader).Assembly.FullName, typeof(Loader).FullName);
            TestHandleProcessCorruptedStateExceptions(loader, myTestAppDomain);

            // how can I make sure process doesn't crash when AppDomain "My Test AppDomain" crashes
            Console.WriteLine("This won't be written to console unless [HandleProcessCorruptedStateExceptions] attribute is present...");

            // keep console window open
            Console.ReadKey();
        }

        // [HandleProcessCorruptedStateExceptions, SecurityCritical]
        private void TestHandleProcessCorruptedStateExceptions(Loader loader, AppDomain appDomain)
        {
            Console.WriteLine("Loading 3rd party lib ClassLibrary1.dll...");
            loader.LoadAssembly(@"..\..\..\ClassLibrary1\bin\debug\ClassLibrary1.dll");
            try
            {
                // executing static method in dummy 3rd party dll in a different app domain (named "My Test AppDomain")
                loader.ExecuteStaticMethod("ClassLibrary1.Class1", "DoStuff", DateTime.Now.ToShortDateString() + " " + DateTime.Now.ToLongTimeString());
            }
            catch (TargetInvocationException)
            {
                AppDomain.Unload(appDomain);
                Console.WriteLine("DoStuff failed. This won't be written to console  unless [HandleProcessCorruptedStateExceptions] attribute is present...");
            }
        }
    }

    class Loader : MarshalByRefObject
    {
        private Assembly _assembly;

        public void LoadAssembly(string path)
        {
            _assembly = Assembly.Load(AssemblyName.GetAssemblyName(path));
        }

        public object ExecuteStaticMethod(string typeName, string methodName, params object[] parameters)
        {
            var type = _assembly.GetType(typeName);
            // assume there is no overloads for simplicity
            var method = type.GetMethod(methodName, BindingFlags.Static | BindingFlags.Public);

            return method.Invoke(null, parameters);
        }
    }
}

这是ClassLibrary1项目中Class1.cs中的代码：

using System;
using System.Runtime.InteropServices;

namespace ClassLibrary1
{
    public class Class1
    {
        public static void DoStuff(string msg)
        {
            Console.WriteLine("Throwing AccessViolationException now...");

            // throw an AccessViolationException which cannot be caught in a try/catch block
            FakeAccessViolationException();

            Console.WriteLine("Class1.DoStuff: " + msg);
        }

        private static void FakeAccessViolationException()
        {
            var ptr = new IntPtr(42);
            Marshal.StructureToPtr(42, ptr, true);
        }
    }
}

不同的AppDomain损坏状态异常（AccessViolationException）应用程序池工作进程

0 个答案: