C#/.NET基于Topshelf建立Windows服务的守护程序做为服务启动的客户端桌面程序不显示UI界面的问题分析和解决方案

本文首发于：码友网--一个专一.NET/.NET Core开发的编程爱好者社区。

文章目录

C#/.NET基于Topshelf建立Windows服务的系列文章目录：

1. C#/.NET基于Topshelf建立Windows服务程序及服务的安装和卸载 (1)
2. 在C#/.NET应用程序开发中建立一个基于Topshelf的应用程序守护进程(服务) (2)
3. C#/.NET基于Topshelf建立Windows服务的守护程序做为服务启动的客户端桌面程序不显示UI界面的问题分析和解决方案 (3)

前言

在上一篇文章《在C#/.NET应用程序开发中建立一个基于Topshelf的应用程序守护进程(服务)》的最后，我给你们抛出了一个遗留的问题--在将TopshelfDemoService程序做为Windows服务安装的状况下，由它守护并启动的客户端程序是没有UI界面的。到这里，咱们得分析为何会出现这个问题，为何在桌面应用程序模式下能够显示UI界面，而在服务模式下没有UI界面？

分析问题(Session 0 隔离)

经过查阅资料，这是因为Session 0 隔离做用的结果。那么什么又是Session 0 隔离呢？

在Windows XP、Windows Server 2003 或早期Windows 系统时代，当第一个用户登陆系统后服务和应用程序是在同一个Session 中运行的。这就是Session 0 以下图所示：

可是这种运行方式提升了系统安全风险，由于服务是经过提高了用户权限运行的，而应用程序每每是那些不具有管理员身份的普通用户运行的，其中的危险显而易见。

从Vista 开始Session 0 中只包含系统服务，其余应用程序则经过分离的Session 运行，将服务与应用程序隔离提升系统的安全性。以下图所示：

这样使得Session 0 与其余Session 之间没法进行交互，不能经过服务向桌面用户弹出信息窗口、UI 窗口等信息。这也就是为何刚才我说那个图已经不能经过当前桌面进行截图了。

潜在的问题

解决方案

在了解了Session 0 隔离以后，给出一些有关建立服务程序以及由服务托管的驱动程序的建议：

一、与应用程序通讯时，使用RPC、命名管道等C/S模式代替窗口消息
二、若是服务程序须要UI与用户交互的话，有两种方式：

①用WTSSendMessage来建立一个消息框与用户交互
②使用一个代理（agent）来完成跟用户的交互，服务程序经过CreateProcessAsUser建立代理。
    并用RPC或者命名管道等方式跟代理通讯，从而完成复杂的界面交互。

三、应该在用户的Session中查询显示属性，若是在Session 0中作这件事，将会获得不正确的结果。
四、明确地使用Local或者Global为命名对象命名，Local/为Session/<n>/BaseNamedObject/，Global/为BaseNamedObject/
五、将程序放在实际环境中测试是最好的方法，若是条件不容许，能够在XP的FUS下测试。在XP的FUS下能工做的服务程序将极可能能够在新版系统中工做，注意XP的FUS下的测试不能检测到在Session 0下跟视频驱动有关的问题

本文咱们的服务程序将经过CreateProcessAsUser建立代理来实现Session 0隔离的穿透。

在项目[TopshelfDemoService]中建立一个静态扩展帮助类ProcessExtensions.cs，代码以下：

using System;
using System.Runtime.InteropServices;

namespace TopshelfDemoService
{
    /// <summary>
    /// 进程静态扩展类
    /// </summary>
    public static class ProcessExtensions
    {
        #region Win32 Constants

        private const int CREATE_UNICODE_ENVIRONMENT = 0x00000400;
        private const int CREATE_NO_WINDOW = 0x08000000;

        private const int CREATE_NEW_CONSOLE = 0x00000010;

        private const uint INVALID_SESSION_ID = 0xFFFFFFFF;
        private static readonly IntPtr WTS_CURRENT_SERVER_HANDLE = IntPtr.Zero;

        #endregion

        #region DllImports

        [DllImport("advapi32.dll", EntryPoint = "CreateProcessAsUser", SetLastError = true, CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)]
        private static extern bool CreateProcessAsUser(
            IntPtr hToken,
            String lpApplicationName,
            String lpCommandLine,
            IntPtr lpProcessAttributes,
            IntPtr lpThreadAttributes,
            bool bInheritHandle,
            uint dwCreationFlags,
            IntPtr lpEnvironment,
            String lpCurrentDirectory,
            ref STARTUPINFO lpStartupInfo,
            out PROCESS_INFORMATION lpProcessInformation);

        [DllImport("advapi32.dll", EntryPoint = "DuplicateTokenEx")]
        private static extern bool DuplicateTokenEx(
            IntPtr ExistingTokenHandle,
            uint dwDesiredAccess,
            IntPtr lpThreadAttributes,
            int TokenType,
            int ImpersonationLevel,
            ref IntPtr DuplicateTokenHandle);

        [DllImport("userenv.dll", SetLastError = true)]
        private static extern bool CreateEnvironmentBlock(ref IntPtr lpEnvironment, IntPtr hToken, bool bInherit);

        [DllImport("userenv.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool DestroyEnvironmentBlock(IntPtr lpEnvironment);

        [DllImport("kernel32.dll", SetLastError = true)]
        private static extern bool CloseHandle(IntPtr hSnapshot);

        [DllImport("kernel32.dll")]
        private static extern uint WTSGetActiveConsoleSessionId();

        [DllImport("Wtsapi32.dll")]
        private static extern uint WTSQueryUserToken(uint SessionId, ref IntPtr phToken);

        [DllImport("wtsapi32.dll", SetLastError = true)]
        private static extern int WTSEnumerateSessions(
            IntPtr hServer,
            int Reserved,
            int Version,
            ref IntPtr ppSessionInfo,
            ref int pCount);

        #endregion

        #region Win32 Structs

        private enum SW
        {
            SW_HIDE = 0,
            SW_SHOWNORMAL = 1,
            SW_NORMAL = 1,
            SW_SHOWMINIMIZED = 2,
            SW_SHOWMAXIMIZED = 3,
            SW_MAXIMIZE = 3,
            SW_SHOWNOACTIVATE = 4,
            SW_SHOW = 5,
            SW_MINIMIZE = 6,
            SW_SHOWMINNOACTIVE = 7,
            SW_SHOWNA = 8,
            SW_RESTORE = 9,
            SW_SHOWDEFAULT = 10,
            SW_MAX = 10
        }

        private enum WTS_CONNECTSTATE_CLASS
        {
            WTSActive,
            WTSConnected,
            WTSConnectQuery,
            WTSShadow,
            WTSDisconnected,
            WTSIdle,
            WTSListen,
            WTSReset,
            WTSDown,
            WTSInit
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct PROCESS_INFORMATION
        {
            public IntPtr hProcess;
            public IntPtr hThread;
            public uint dwProcessId;
            public uint dwThreadId;
        }

        private enum SECURITY_IMPERSONATION_LEVEL
        {
            SecurityAnonymous = 0,
            SecurityIdentification = 1,
            SecurityImpersonation = 2,
            SecurityDelegation = 3,
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct STARTUPINFO
        {
            public int cb;
            public String lpReserved;
            public String lpDesktop;
            public String lpTitle;
            public uint dwX;
            public uint dwY;
            public uint dwXSize;
            public uint dwYSize;
            public uint dwXCountChars;
            public uint dwYCountChars;
            public uint dwFillAttribute;
            public uint dwFlags;
            public short wShowWindow;
            public short cbReserved2;
            public IntPtr lpReserved2;
            public IntPtr hStdInput;
            public IntPtr hStdOutput;
            public IntPtr hStdError;
        }

        private enum TOKEN_TYPE
        {
            TokenPrimary = 1,
            TokenImpersonation = 2
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct WTS_SESSION_INFO
        {
            public readonly UInt32 SessionID;

            [MarshalAs(UnmanagedType.LPStr)]
            public readonly String pWinStationName;

            public readonly WTS_CONNECTSTATE_CLASS State;
        }

        #endregion

        // Gets the user token from the currently active session
        private static bool GetSessionUserToken(ref IntPtr phUserToken)
        {
            var bResult = false;
            var hImpersonationToken = IntPtr.Zero;
            var activeSessionId = INVALID_SESSION_ID;
            var pSessionInfo = IntPtr.Zero;
            var sessionCount = 0;

            // Get a handle to the user access token for the current active session.
            if (WTSEnumerateSessions(WTS_CURRENT_SERVER_HANDLE, 0, 1, ref pSessionInfo, ref sessionCount) != 0)
            {
                var arrayElementSize = Marshal.SizeOf(typeof(WTS_SESSION_INFO));
                var current = pSessionInfo;

                for (var i = 0; i < sessionCount; i++)
                {
                    var si = (WTS_SESSION_INFO)Marshal.PtrToStructure(current, typeof(WTS_SESSION_INFO));
                    current += arrayElementSize;

                    if (si.State == WTS_CONNECTSTATE_CLASS.WTSActive)
                    {
                        activeSessionId = si.SessionID;
                    }
                }
            }

            // If enumerating did not work, fall back to the old method
            if (activeSessionId == INVALID_SESSION_ID)
            {
                activeSessionId = WTSGetActiveConsoleSessionId();
            }

            if (WTSQueryUserToken(activeSessionId, ref hImpersonationToken) != 0)
            {
                // Convert the impersonation token to a primary token
                bResult = DuplicateTokenEx(hImpersonationToken, 0, IntPtr.Zero,
                    (int)SECURITY_IMPERSONATION_LEVEL.SecurityImpersonation, (int)TOKEN_TYPE.TokenPrimary,
                    ref phUserToken);

                CloseHandle(hImpersonationToken);
            }

            return bResult;
        }

        public static bool StartProcessAsCurrentUser(string appPath, string cmdLine = null, string workDir = null, bool visible = true)
        {
            var hUserToken = IntPtr.Zero;
            var startInfo = new STARTUPINFO();
            var procInfo = new PROCESS_INFORMATION();
            var pEnv = IntPtr.Zero;
            int iResultOfCreateProcessAsUser;

            startInfo.cb = Marshal.SizeOf(typeof(STARTUPINFO));

            try
            {
                if (!GetSessionUserToken(ref hUserToken))
                {
                    throw new Exception("StartProcessAsCurrentUser: GetSessionUserToken failed.");
                }

                uint dwCreationFlags = CREATE_UNICODE_ENVIRONMENT | (uint)(visible ? CREATE_NEW_CONSOLE : CREATE_NO_WINDOW);
                startInfo.wShowWindow = (short)(visible ? SW.SW_SHOW : SW.SW_HIDE);
                startInfo.lpDesktop = "winsta0\\default";

                if (!CreateEnvironmentBlock(ref pEnv, hUserToken, false))
                {
                    throw new Exception("StartProcessAsCurrentUser: CreateEnvironmentBlock failed.");
                }

                if (!CreateProcessAsUser(hUserToken,
                    appPath, // Application Name
                    cmdLine, // Command Line
                    IntPtr.Zero,
                    IntPtr.Zero,
                    false,
                    dwCreationFlags,
                    pEnv,
                    workDir, // Working directory
                    ref startInfo,
                    out procInfo))
                {
                    iResultOfCreateProcessAsUser = Marshal.GetLastWin32Error();
                    throw new Exception("StartProcessAsCurrentUser: CreateProcessAsUser failed.  Error Code -" + iResultOfCreateProcessAsUser);
                }

                iResultOfCreateProcessAsUser = Marshal.GetLastWin32Error();
            }
            finally
            {
                CloseHandle(hUserToken);
                if (pEnv != IntPtr.Zero)
                {
                    DestroyEnvironmentBlock(pEnv);
                }
                CloseHandle(procInfo.hThread);
                CloseHandle(procInfo.hProcess);
            }

            return true;
        }

    }
}

修改ProcessHelper.cs为以下代码：

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;

namespace TopshelfDemoService
{
    /// <summary>
    /// 进程处理帮助类
    /// </summary>
    internal class ProcessorHelper
    {
        /// <summary>
        /// 获取当前计算机全部的进程列表(集合)
        /// </summary>
        /// <returns></returns>
        public static List<Process> GetProcessList()
        {
            return GetProcesses().ToList();
        }

        /// <summary>
        /// 获取当前计算机全部的进程列表(数组)
        /// </summary>
        /// <returns></returns>
        public static Process[] GetProcesses()
        {
            var processList = Process.GetProcesses();
            return processList;
        }

        /// <summary>
        /// 判断指定的进程是否存在
        /// </summary>
        /// <param name="processName"></param>
        /// <returns></returns>
        public static bool IsProcessExists(string processName)
        {
            return Process.GetProcessesByName(processName).Length > 0;
        }

        /// <summary>
        /// 启动一个指定路径的应用程序
        /// </summary>
        /// <param name="applicationPath"></param>
        /// <param name="args"></param>
        public static void RunProcess(string applicationPath, string args = "")
        {
            try
            {
                ProcessExtensions.StartProcessAsCurrentUser(applicationPath, args);
            }
            catch (Exception e)
            {
                var psi = new ProcessStartInfo
                {
                    FileName = applicationPath,
                    WindowStyle = ProcessWindowStyle.Normal,
                    Arguments = args
                };
                Process.Start(psi);
            }
        }
    }
}

其中更改了方法 RunProcess()的调用方式。

从新编译服务程序项目[TopshelfDemoService]，并将它做为Windows服务安装，最后启动服务。守护进程服务将启动一个带UI界面的客户端程序。大功告成！！！

我是Rector，但愿本文的关于Topshelf服务和守护程序设计对须要的朋友有所帮助。

感谢花你宝贵的时间阅读！！！

参考资料

穿透Session 0 隔离（一）
Windows中Session 0隔离对服务程序和驱动程序的影响
CreateProcessAsUser

源代码下载

本示例代码托管地址能够在原出处找到：示例代码下载地址