c# - 为什么在具有两个进程和输出重定向的代码中没有捕获到 ThreadAbortException？

Question

下面的代码仅用于说明问题。请忽略使用 CodeDom 编译源代码的部分。此外，如果您尝试它，它会使“其他进程”可执行文件继续运行并无益地消耗 CPU 时间。

真正的问题是我启动线程，然后中止线程并看到“Thread abort initiated”消息并且有

A first chance exception of type 'System.Threading.ThreadAbortException' occurred in mscorlib.dll

调试器输出中的消息，但 catch 和 finally block 均未被调用，并且这些 block 没有输出。

当然，因为为处理重定向输出而创建的额外线程没有中止，所以程序永远挂起，但是...

为什么 catch 和 finally 没有被调用？

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Threading;
using System.Diagnostics;
using Microsoft.CSharp;
using System.CodeDom.Compiler;

namespace ConsoleApplication
{
  class Program
  {
    static void Main(string[] args)
    {
      new Program().payload();
    }

    private void payload()
    {
      var otherExecutableName = "OtherProcess.exe";
      compileOtherProcessExecutable(otherExecutableName);
      var thread = new System.Threading.Thread(() => threadFunc(otherExecutableName));
      thread.Start();
      Thread.Sleep( 1000 );
      thread.Abort();
      Debug.WriteLine("Thread abort initiated");
    }

    private void threadFunc( String secondExecutableName )
    {
        Process process = null;
        try {
            process = new Process();
            {
                process.StartInfo.FileName = secondExecutableName;
                process.StartInfo.UseShellExecute = false;
                process.StartInfo.RedirectStandardOutput = true;
                process.StartInfo.RedirectStandardError = true;

                process.OutputDataReceived += new DataReceivedEventHandler(outputHandler);
                process.ErrorDataReceived += new DataReceivedEventHandler(outputHandler);

                process.Start();

                process.BeginOutputReadLine();
                process.BeginErrorReadLine();

                process.WaitForExit();
            }
        } catch( Exception e ) {
            Debug.WriteLine( "Catch block: " + e.Message );
        } finally {
            Debug.WriteLine( "Finally block" );
            if( process != null ) {
                process.Kill();
                Debug.WriteLine( "Process killed" );
            }
        }
    }

    static void compileOtherProcessExecutable(string filePath)
    {
        using (var compiler = new CSharpCodeProvider())
        {
            var parameters = new CompilerParameters(null, filePath, true);
            parameters.GenerateExecutable = true;
            var compResult = compiler.CompileAssemblyFromSource( parameters, otherProcessCode);
            var errs = compResult.Errors;
            if (errs.HasErrors)
            {
                var err = errs.Cast<CompilerError>().First();
                throw new InvalidOperationException(String.Format(
                    "Compilation failed. Line {0}: {1}", err.Line, err.ErrorText));
            }
        }
    }

    private void outputHandler(object process, DataReceivedEventArgs output)
    {
    }

    static readonly String otherProcessCode =
        @"class Program {
            public static void Main(string[] args)
            {
                while( true ) {
                }
            }
        }";
  }
}

Answer 1

问题是 WaitForExit 调用。此托管调用最终将在 native 框架中触底。当线程处于 native 代码中时发生 Abort 调用时，在线程返回到托管代码之前什么都不会发生。在这种情况下，线程正在等待进程完成，因此在您实际终止进程之前不会真正返回

注意:即使抛出异常，catch block 也不会真正捕获它。异常将在 block 的末尾重新抛出。您需要捕获它并调用 ResetAbort 方法