[英]How to prevent WMI quotas from overflowing?
我正在使用C#应用程序监视从特定文件夹启动的进程,并且正在使用WMI进行监视。 我的WMI查询就像
SELECT * FROM __InstanceCreationEvent WITHIN 5 WHERE TargetInstance ISA 'Win32_Process' AND TargetInstance.ExecutablePath LIKE '{0}%'
在这里,我将参数替换为插入的文件夹的路径。 WMI查询工作正常,当来自特定文件夹的进程出现时,我正在订阅事件通知以进行一些其他处理。 监视工具可以正常运行数小时,之后我开始在我的应用程序中收到WMI QuotaViolation
异常。 一旦发生这种情况,我需要重新启动Windows Management Instrumentation
服务以使该设备正常工作。 我最初使用的是
`SELECT * FROM __InstanceCreationEvent WITHIN 5 WHERE TargetInstance ISA 'Win32_Process'`
查询,然后检查事件通知中的processs文件夹,查询中的修改已完成,希望它会减少结果集并因此防止违反配额。
有什么方法可以定期刷新WMI配额,或者可以防止QuotaViolation的其他任何方法? 处理QuotaViolation方案的最佳方法是什么?
编辑:这是我的流程观察者对象:
public class ProcessWatcher : ManagementEventWatcher
{
private string folder = "";
// Process Events
public event ProcessEventHandler ProcessCreated; //notifies process creation
//add any more event notifications required here
// WMI WQL process query strings
static readonly string WMI_OPER_EVENT_QUERY = @"SELECT * FROM __InstanceCreationEvent WITHIN 5 WHERE TargetInstance ISA 'Win32_Process'";
static readonly string WMI_OPER_EVENT_QUERY_WITH_PROC =
WMI_OPER_EVENT_QUERY + " and TargetInstance.Name = '{0}'";
public ProcessWatcher(string basepath)
{
folder = basepath;
Init(string.Empty);
}
public ProcessWatcher(string processName, string basepath)
{
folder = basepath;
Init(processName);
}
private void Init(string processName)
{
this.Query.QueryLanguage = "WQL";
if (string.IsNullOrEmpty(processName))
{
this.Query.QueryString = string.Format(WMI_OPER_EVENT_QUERY + @" AND TargetInstance.ExecutablePath LIKE '{0}%'", folder.Replace(@"\",@"\\")) ;
}
else
{
this.Query.QueryString =
string.Format(WMI_OPER_EVENT_QUERY_WITH_PROC, processName);
}
this.EventArrived += new EventArrivedEventHandler(watcher_EventArrived);
}
private void watcher_EventArrived(object sender, EventArrivedEventArgs e)
{
try
{
ManagementBaseObject mObj = e.NewEvent["TargetInstance"] as ManagementBaseObject;
if (mObj != null)
{
Win32_Process proc = new Win32_Process(mObj);
if (proc != null)
{
folder = folder.ToLower() ?? "";
string exepath = (string.IsNullOrEmpty(proc.ExecutablePath)) ? "" : proc.ExecutablePath.ToLower();
if (!string.IsNullOrEmpty(folder) && !string.IsNullOrEmpty(exepath) && exepath.Contains(folder))
{
if (ProcessCreated != null) ProcessCreated(proc);
}
}
proc.Dispose();
}
mObj.Dispose();
}
catch(Exception ex) { throw; }
finally
{
e.NewEvent.Dispose();
}
}
我在应用启动时在一个像这样的viewmodel构造函数中创建一个ProcessWatcher
对象:
watch = new ProcessWatcher(BasePath);
watch.ProcessCreated += new ProcessEventHandler(procWatcher_ProcessCreated);
watch.Start();
如果我尝试在不重新启动WMI的情况下第二次启动QuotaViolation
则会在start调用处引发该调用。 在应用程序出口处,我正在处理ProcessWatcher
对象,例如:
watch.Stop();
watch.Dispose();
相关堆栈跟踪为:
异常InnerException [System.Management.ManagementException:违反配额
在System.Management.ManagementException.ThrowWithExtendedInfo(ManagementStatus errorCode)
在System.Management.ManagementEventWatcher.Start()
在App.ProcessTabViewModel1..ctor()
System.Management.ManagementException:违反配额
是的,那会发生。 在添加缺失的部分之后,我根据您的代码片段编写了一个小测试程序:
static void Main(string[] args) {
for (int ix = 0; ix < 1000; ++ix) {
var obj = new ProcessWatcher("");
obj.ProcessCreated += obj_ProcessCreated;
obj.Start();
}
}
KABOOM! 与您引用的堆栈跟踪完全相同。 它以ix == 76表示。换句话说,此查询的WMI配额为75。在Windows 8.1中进行了测试。 感觉不错,这是一个非常昂贵的查询,也不是太快。
您将不得不从根本上进行此操作,仅创建一个查询。 一个就足够了,对许多文件夹执行此操作可能会遇到麻烦。 采取不同的攻击方式,在获得事件时进行自己的过滤。 一个粗略的例子(我没有完全得到想要的过滤):
public class ProcessWatcher2 : IDisposable {
public delegate void ProcessCreateEvent(string name, string path);
public event ProcessCreateEvent ProcessCreated;
public ProcessWatcher2(string folder) {
this.folder = folder;
lock (locker) {
listeners.Add(this);
if (watcher == null) Initialize();
}
}
public void Dispose() {
lock (locker) {
listeners.Remove(this);
if (listeners.Count == 0) {
watcher.Stop();
watcher.Dispose();
watcher = null;
}
}
}
private static void Initialize() {
var query = new WqlEventQuery(@"SELECT * FROM __InstanceCreationEvent WITHIN 5 WHERE TargetInstance ISA 'Win32_Process'");
watcher = new ManagementEventWatcher(query);
watcher.EventArrived += watcher_EventArrived;
watcher.Start();
}
private static void watcher_EventArrived(object sender, EventArrivedEventArgs e) {
using (var proc = (ManagementBaseObject)e.NewEvent["TargetInstance"]) {
string name = (string)proc.Properties["Name"].Value;
string path = (string)proc.Properties["ExecutablePath"].Value;
lock (locker) {
foreach (var listener in listeners) {
bool filtered = false;
// Todo: implement your filtering
//...
var handler = listener.ProcessCreated;
if (!filtered && handler != null) {
handler(name, path);
}
}
}
}
}
private static ManagementEventWatcher watcher;
private static List<ProcessWatcher2> listeners = new List<ProcessWatcher2>();
private static object locker = new object();
private string folder;
}
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