C# 获取句柄列表，AcessViolationException

Question

信息:

• .Net 4.5

测试于:

• Win7 64 位

• Win10 64 位(虚拟盒子)

我正在尝试获取一个外部进程的句柄列表，并将它们的名称作为字符串返回，这样我就可以在之后关闭一个特定的进程。因此我使用 Win32API 编写了这个函数，它将检查句柄是否是我想要关闭的句柄:`

        const int CNST_SYSTEM_HANDLE_INFORMATION = 16;
        const uint STATUS_INFO_LENGTH_MISMATCH = 0xc0000004;

        public static string getObjectTypeName(Win32API.SYSTEM_HANDLE_INFORMATION shHandle, Process process)
        {
            IntPtr m_ipProcessHwnd = Win32API.OpenProcess(Win32API.ProcessAccessFlags.All, false, process.Id);
            IntPtr ipHandle = IntPtr.Zero;
            var objBasic = new Win32API.OBJECT_BASIC_INFORMATION();
            IntPtr ipBasic = IntPtr.Zero;
            var objObjectType = new Win32API.OBJECT_TYPE_INFORMATION();
            IntPtr ipObjectType = IntPtr.Zero;
            IntPtr ipObjectName = IntPtr.Zero;
            string strObjectTypeName = "";
            int nLength = 0;
            int nReturn = 0;
            IntPtr ipTemp = IntPtr.Zero;


            if (!Win32API.DuplicateHandle(m_ipProcessHwnd, shHandle.Handle,
                                          Win32API.GetCurrentProcess(), out ipHandle,
                                          0, false, Win32API.DUPLICATE_SAME_ACCESS))
                return null;



            ipBasic = Marshal.AllocHGlobal(Marshal.SizeOf(objBasic));
            Win32API.NtQueryObject(ipHandle, (int)Win32API.ObjectInformationClass.ObjectBasicInformation,
                                   ipBasic, Marshal.SizeOf(objBasic), ref nLength);
            objBasic = (Win32API.OBJECT_BASIC_INFORMATION)Marshal.PtrToStructure(ipBasic, objBasic.GetType());
            Marshal.FreeHGlobal(ipBasic);

            ipObjectType = Marshal.AllocHGlobal(objBasic.TypeInformationLength);
            nLength = objBasic.TypeInformationLength;
            while ((uint)(nReturn = Win32API.NtQueryObject(
                ipHandle, (int)Win32API.ObjectInformationClass.ObjectTypeInformation, ipObjectType,
                  nLength, ref nLength)) ==
                Win32API.STATUS_INFO_LENGTH_MISMATCH)
            {
                Marshal.FreeHGlobal(ipObjectType);
                ipObjectType = Marshal.AllocHGlobal(nLength);
            }

            objObjectType = (Win32API.OBJECT_TYPE_INFORMATION)Marshal.PtrToStructure(ipObjectType, objObjectType.GetType());
            if (Is64Bits())
            {
                ipTemp = new IntPtr(Convert.ToInt64(objObjectType.Name.Buffer.ToString(), 10) >> 32);
            }
            else
            {
                ipTemp = objObjectType.Name.Buffer;
            }

        strObjectTypeName = Marshal.PtrToStringUni(ipTemp, objObjectType.Name.Length >> 1);


        Marshal.FreeHGlobal(ipObjectType);
            Win32API.CloseHandle(ipHandle);
            return strObjectTypeName;
        }`

但问题是这段代码在 Win7 64 位中有效，在 Win10 中无效! --> 在 Win 10 中 strObjectTypeName = Marshal.PtrToStringUni(); 抛出一个 AcessViolationException(代码中的最后几行)

System.AccessViolationException Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

我是否遗漏了有关在 win10 中必须如何访问非托管内存的内容？

Answer 1

我刚遇到同样的问题。我没有尝试过 Win7，但是当您在 Win10(x64) 上以 32 位运行代码时(例如，设置应用程序的“首选 32 位标志”)它应该可以工作。当异常发生时，将变量“ipTemp”拖放到Visual Studio的“内存窗口”中，如果它只显示问号或错误消息则您没有有效的指针。据我所知，此 API 使用的结构的 64 位版本中有(更多)填充字节:OBJECT_TYPE_INFORMATION 包含一个 UNICODE_STRING 并且 UNICODE_STRING 在 64 位模式的缓冲区字段之前有 4 个填充字节。我的解决方法是:

[StructLayout(LayoutKind.Sequential, Pack = 1)]
public struct UNICODE_STRING
{
    private IntPtr _dummy; // the two ushorts seem to be padded with 4 bytes in 64bit mode only

    /// <summary>
    /// The length, in bytes, of the string stored in Buffer. If the string is null-terminated, Length does not include the trailing null character.
    /// </summary>
    public ushort Length
    {
        get { return (ushort)Marshal.ReadInt16(this, 0); }
    }

    /// <summary>
    /// The length, in bytes, of Buffer.
    /// </summary>
    public ushort MaximumLength
    {
        get { return (ushort)Marshal.ReadInt16(this, 2); }
    }

    public IntPtr Buffer;
}

在我的研究过程中，我发现了很多关于这个主题的问题，基本上有两种示例代码我正在考虑创建一个名为 WinKernelObjectsDotNet 的开源库。

更新:库现已可用here .它支持使用一行代码查找锁定文件或串行端口 (COM) 的进程。