在window form程序中, 获取当前用户的信息是很容易的一件事情。然而,在window service中, 如何获取当前活动的(登陆的)用户的信息,.NET 并没有给出一种很容易的方法。多数情况下,用户需要调用底层API以达到此目的。如果想在services中启动一个线程并且运行在当前活动的用户UI界面上,获取当前活动的用户,更是必须的操作。
在windows底层的api中,提供了以下的方法来满足需求:
WTSGetActiveConsoleSessionId: 获取当前active User的 session ID。
CreateProcessAsUser:用当前用户创建一个新的进程。
下面的程序提供了两个方法,一是获取当前活动的用户包括域名和用户名,二是用当前用户创建一个新的进程。
using System;
using System.Security;
using System.Diagnostics;
using System.Runtime.InteropServices;
namespace NS_UserTest
{
/// <summary>
/// Class that allows running applications with full admin rights. In
/// addition the application launched will bypass the Vista UAC prompt.
/// </summary>
public class ApplicationLoader
{
#region Structures
[StructLayout(LayoutKind.Sequential)]
public struct SECURITY_ATTRIBUTES
{
public int Length;
public IntPtr lpSecurityDescriptor;
public bool bInheritHandle;
}
[StructLayout(LayoutKind.Sequential)]
public 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;
}
[StructLayout(LayoutKind.Sequential)]
public struct PROCESS_INFORMATION
{
public IntPtr hProcess;
public IntPtr hThread;
public uint dwProcessId;
public uint dwThreadId;
}
#endregion
#region Enumerations
enum TOKEN_TYPE : int
{
TokenPrimary = 1,
TokenImpersonation = 2
}
enum SECURITY_IMPERSONATION_LEVEL : int
{
SecurityAnonymous = 0,
SecurityIdentification = 1,
SecurityImpersonation = 2,
SecurityDelegation = 3,
}
enum WTSInfoClass
{
InitialProgram,
ApplicationName,
WorkingDirectory,
OEMId,
SessionId,
UserName,
WinStationName,
DomainName,
ConnectState,
ClientBuildNumber,
ClientName,
ClientDirectory,
ClientProductId,
ClientHardwareId,
ClientAddress,
ClientDisplay,
ClientProtocolType
}
#endregion
#region Constants
public const int TOKEN_DUPLICATE = 0x0002;
public const uint MAXIMUM_ALLOWED = 0x2000000;
public const int CREATE_NEW_CONSOLE = 0x00000010;
public const int IDLE_PRIORITY_CLASS = 0x40;
public const int NORMAL_PRIORITY_CLASS = 0x20;
public const int HIGH_PRIORITY_CLASS = 0x80;
public const int REALTIME_PRIORITY_CLASS = 0x100;
#endregion
#region Win32 API Imports
[DllImport("kernel32.dll", SetLastError = true)]
private static extern bool CloseHandle(IntPtr hSnapshot);
[DllImport("kernel32.dll")]
static extern uint WTSGetActiveConsoleSessionId();
[DllImport("wtsapi32.dll", CharSet = CharSet.Unicode, SetLastError = true), SuppressUnmanagedCodeSecurityAttribute]
static extern bool WTSQuerySessionInformation(System.IntPtr hServer, int sessionId, WTSInfoClass wtsInfoClass, out System.IntPtr ppBuffer, out uint pBytesReturned);
[DllImport("advapi32.dll", EntryPoint = "CreateProcessAsUser", SetLastError = true, CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)]
public extern static bool CreateProcessAsUser(IntPtr hToken, String lpApplicationName, String lpCommandLine, ref SECURITY_ATTRIBUTES lpProcessAttributes,
ref SECURITY_ATTRIBUTES lpThreadAttributes, bool bInheritHandle, int dwCreationFlags, IntPtr lpEnvironment,
String lpCurrentDirectory, ref STARTUPINFO lpStartupInfo, out PROCESS_INFORMATION lpProcessInformation);
[DllImport("kernel32.dll")]
static extern bool ProcessIdToSessionId(uint dwProcessId, ref uint pSessionId);
[DllImport("advapi32.dll", EntryPoint = "DuplicateTokenEx")]
public extern static bool DuplicateTokenEx(IntPtr ExistingTokenHandle, uint dwDesiredAccess,
ref SECURITY_ATTRIBUTES lpThreadAttributes, int TokenType,
int ImpersonationLevel, ref IntPtr DuplicateTokenHandle);
[DllImport("kernel32.dll")]
static extern IntPtr OpenProcess(uint dwDesiredAccess, bool bInheritHandle, uint dwProcessId);
[DllImport("advapi32", SetLastError = true), SuppressUnmanagedCodeSecurityAttribute]
static extern bool OpenProcessToken(IntPtr ProcessHandle, int DesiredAccess, ref IntPtr TokenHandle);
#endregion
public static string GetCurrentActiveUser()
{
IntPtr hServer = IntPtr.Zero, state = IntPtr.Zero;
uint bCount = 0;
// obtain the currently active session id; every logged on user in the system has a unique session id
uint dwSessionId = WTSGetActiveConsoleSessionId();
string domain = string.Empty, userName = string.Empty;
if (WTSQuerySessionInformation(hServer, (int)dwSessionId, WTSInfoClass.DomainName, out state, out bCount))
{
domain = Marshal.PtrToStringAuto(state);
}
if (WTSQuerySessionInformation(hServer, (int)dwSessionId, WTSInfoClass.UserName, out state, out bCount))
{
userName = Marshal.PtrToStringAuto(state);
}
return string.Format("{0}\\{1}", domain, userName);
}
/// <summary>
/// Launches the given application with full admin rights, and in addition bypasses the Vista UAC prompt
/// </summary>
/// <param name="applicationName">The name of the application to launch</param>
/// <param name="procInfo">Process information regarding the launched application that gets returned to the caller</param>
/// <returns></returns>
public static bool StartProcessAndBypassUAC(String applicationName, String command, out PROCESS_INFORMATION procInfo)
{
uint winlogonPid = 0;
IntPtr hUserTokenDup = IntPtr.Zero, hPToken = IntPtr.Zero, hProcess = IntPtr.Zero;
procInfo = new PROCESS_INFORMATION();
// obtain the currently active session id; every logged on user in the system has a unique session id
uint dwSessionId = WTSGetActiveConsoleSessionId();
// obtain the process id of the winlogon process that is running within the currently active session
Process[] processes = Process.GetProcessesByName("winlogon");
foreach (Process p in processes)
{
if ((uint)p.SessionId == dwSessionId)
{
winlogonPid = (uint)p.Id;
}
}
// obtain a handle to the winlogon process
hProcess = OpenProcess(MAXIMUM_ALLOWED, false, winlogonPid);
// obtain a handle to the access token of the winlogon process
if (!OpenProcessToken(hProcess, TOKEN_DUPLICATE, ref hPToken))
{
CloseHandle(hProcess);
return false;
}
// Security attibute structure used in DuplicateTokenEx and CreateProcessAsUser
// I would prefer to not have to use a security attribute variable and to just
// simply pass null and inherit (by default) the security attributes
// of the existing token. However, in C# structures are value types and therefore
// cannot be assigned the null value.
SECURITY_ATTRIBUTES sa = new SECURITY_ATTRIBUTES();
sa.Length = Marshal.SizeOf(sa);
// copy the access token of the winlogon process; the newly created token will be a primary token
if (!DuplicateTokenEx(hPToken, MAXIMUM_ALLOWED, ref sa, (int)SECURITY_IMPERSONATION_LEVEL.SecurityIdentification, (int)TOKEN_TYPE.TokenPrimary, ref hUserTokenDup))
{
CloseHandle(hProcess);
CloseHandle(hPToken);
return false;
}
// By default CreateProcessAsUser creates a process on a non-interactive window station, meaning
// the window station has a desktop that is invisible and the process is incapable of receiving
// user input. To remedy this we set the lpDesktop parameter to indicate we want to enable user
// interaction with the new process.
STARTUPINFO si = new STARTUPINFO();
si.cb = (int)Marshal.SizeOf(si);
si.lpDesktop = @"winsta0\default"; // interactive window station parameter; basically this indicates that the process created can display a GUI on the desktop
// flags that specify the priority and creation method of the process
int dwCreationFlags = NORMAL_PRIORITY_CLASS | CREATE_NEW_CONSOLE;
// create a new process in the current user's logon session
bool result = CreateProcessAsUser(hUserTokenDup, // client's access token
applicationName, // file to execute
command, // command line
ref sa, // pointer to process SECURITY_ATTRIBUTES
ref sa, // pointer to thread SECURITY_ATTRIBUTES
false, // handles are not inheritable
dwCreationFlags, // creation flags
IntPtr.Zero, // pointer to new environment block
null, // name of current directory
ref si, // pointer to STARTUPINFO structure
out procInfo // receives information about new process
);
// invalidate the handles
CloseHandle(hProcess);
CloseHandle(hPToken);
CloseHandle(hUserTokenDup);
return result; // return the result
}
}
}
下面给出使用此静态方法的事例:
private void RunCommand(object state)
{
try
{
var cmdBatch = state as string;
if (string.IsNullOrEmpty(cmdBatch))
return;
string applicationName = null;
if (Path.GetExtension(cmdBatch).Equals(".BAT"))
applicationName = "cmd.exe";
// launch the application
ApplicationLoader.PROCESS_INFORMATION procInfo;
ApplicationLoader.StartProcessAndBypassUAC(applicationName, "\"" + cmdBatch + "\"", out procInfo);
// check the process and get the complete or not.
var process = Process.GetProcessById((int)procInfo.dwProcessId);
if(process != null)
process.WaitForExit();
}
catch (Exception ex)
{
EventLog.WriteEntry(ex.Message, System.Diagnostics.EventLogEntryType.Error);
}
}
通过以上的方法,可以看到,当前启动的进程运行在活动用户的界面。