EventWaitHandle.SetAccessControl(EventWaitHandleSecurity) Methode

Definition

Legt die Zugriffssteuerungssicherheit für ein benanntes Systemereignis fest.Sets the access control security for a named system event.

public:
 void SetAccessControl(System::Security::AccessControl::EventWaitHandleSecurity ^ eventSecurity);
public void SetAccessControl (System.Security.AccessControl.EventWaitHandleSecurity eventSecurity);
member this.SetAccessControl : System.Security.AccessControl.EventWaitHandleSecurity -> unit
Public Sub SetAccessControl (eventSecurity As EventWaitHandleSecurity)

Parameter

eventSecurity
EventWaitHandleSecurity

Ein EventWaitHandleSecurity-Objekt, das die Zugriffssteuerungssicherheit darstellt, die auf das benannte Systemereignis angewendet werden soll.An EventWaitHandleSecurity object that represents the access control security to be applied to the named system event.

Ausnahmen

eventSecurity ist null.eventSecurity is null.

Der Benutzer verfügt nicht über ChangePermissions.The user does not have ChangePermissions.

- oder --or- Das Ereignis wurde nicht mit ChangePermissions geöffnet.The event was not opened with ChangePermissions.

Die aktuelle EventWaitHandle-Objekt stellt kein benanntes Systemereignis dar.The current EventWaitHandle object does not represent a named system event.

Die Close()-Methode wurde zuvor für diesen EventWaitHandle aufgerufen.The Close() method was previously called on this EventWaitHandle.

Beispiele

Im folgenden Codebeispiel wird das prozessübergreifende Verhalten eines benannten System Ereignisses mit Zugriffs Steuerungs Sicherheit veranschaulicht.The following code example demonstrates the cross-process behavior of a named system event with access control security. Im Beispiel wird die OpenExisting(String)-Methoden Überladung verwendet, um zu testen, ob ein benanntes Ereignis vorhanden ist.The example uses the OpenExisting(String) method overload to test for the existence of a named event.

Wenn das Ereignis nicht vorhanden ist, wird es mit dem anfänglichen Besitz und der Zugriffs Steuerungs Sicherheit erstellt, die dem aktuellen Benutzer das Recht verweigert, das Ereignis zu verwenden, gewährt jedoch das Recht, Lese-und Änderungs Berechtigungen für das Ereignis zu erteilen.If the event does not exist, it is created with initial ownership and access control security that denies the current user the right to use the event, but grants the right to read and change permissions on the event.

Wenn Sie das kompilierte Beispiel aus zwei Befehls Fenstern ausführen, löst die zweite Kopie beim Aufrufen von OpenExisting(String)eine Zugriffs Verletzungs Ausnahme aus.If you run the compiled example from two command windows, the second copy will throw an access violation exception on the call to OpenExisting(String). Die Ausnahme wird abgefangen, und das Beispiel verwendet die OpenExisting(String, EventWaitHandleRights)-Methoden Überladung, um auf das Ereignis mit den rechten zu warten, die zum Lesen und Ändern der Berechtigungen erforderlich sind.The exception is caught, and the example uses the OpenExisting(String, EventWaitHandleRights) method overload to wait on the event with the rights needed to read and change the permissions.

Nachdem die Berechtigungen mithilfe der SetAccessControl-Methode geändert wurden, wird das Ereignis mit den Rechten geöffnet, die erforderlich sind, um darauf zu warten und es zu signalisieren.After the permissions are changed, using the SetAccessControl method, the event is opened with the rights required to wait on it and signal it. Wenn Sie das kompilierte Beispiel aus einem dritten Befehlsfenster ausführen, wird das Beispiel mithilfe der neuen Berechtigungen ausgeführt.If you run the compiled example from a third command window, the example runs using the new permissions.

using namespace System;
using namespace System::Threading;
using namespace System::Security::AccessControl;
using namespace System::Security::Permissions;

public ref class Example
{
public:
   [SecurityPermissionAttribute(SecurityAction::Demand,Flags=SecurityPermissionFlag::UnmanagedCode)]
   static void Main()
   {
      String^ ewhName = L"EventWaitHandleExample5";

      EventWaitHandle^ ewh = nullptr;
      bool doesNotExist = false;
      bool unauthorized = false;
      
      // The value of this variable is set by the event
      // constructor. It is true if the named system event was
      // created, and false if the named event already existed.
      //
      bool wasCreated;
      
      // Attempt to open the named event.
      try
      {
         // Open the event with (EventWaitHandleRights.Synchronize
         // | EventWaitHandleRights.Modify), to wait on and
         // signal the named event.
         //
         ewh = EventWaitHandle::OpenExisting( ewhName );
      }
      catch ( WaitHandleCannotBeOpenedException^ ) 
      {
         Console::WriteLine( L"Named event does not exist." );
         doesNotExist = true;
      }
      catch ( UnauthorizedAccessException^ ex ) 
      {
         Console::WriteLine( L"Unauthorized access: {0}", ex->Message );
         unauthorized = true;
      }

      // There are three cases: (1) The event does not exist.
      // (2) The event exists, but the current user doesn't
      // have access. (3) The event exists and the user has
      // access.
      //
      if ( doesNotExist )
      {
         // The event does not exist, so create it.

         // Create an access control list (ACL) that denies the
         // current user the right to wait on or signal the
         // event, but allows the right to read and change
         // security information for the event.
         //
         String^ user = String::Concat( Environment::UserDomainName, L"\\",
            Environment::UserName );
         EventWaitHandleSecurity^ ewhSec = gcnew EventWaitHandleSecurity;
         //following constructor fails
         EventWaitHandleAccessRule^ rule = gcnew EventWaitHandleAccessRule(
            user,
            static_cast<EventWaitHandleRights>(
               EventWaitHandleRights::Synchronize | 
               EventWaitHandleRights::Modify),
            AccessControlType::Deny );
         ewhSec->AddAccessRule( rule );

         rule = gcnew EventWaitHandleAccessRule( user,
            static_cast<EventWaitHandleRights>(
               EventWaitHandleRights::ReadPermissions | 
               EventWaitHandleRights::ChangePermissions),
            AccessControlType::Allow );
         ewhSec->AddAccessRule( rule );
         
         // Create an EventWaitHandle object that represents
         // the system event named by the constant 'ewhName',
         // initially signaled, with automatic reset, and with
         // the specified security access. The Boolean value that
         // indicates creation of the underlying system object
         // is placed in wasCreated.
         //
         ewh = gcnew EventWaitHandle( true,
            EventResetMode::AutoReset,
            ewhName,
            wasCreated,
            ewhSec );
         
         // If the named system event was created, it can be
         // used by the current instance of this program, even
         // though the current user is denied access. The current
         // program owns the event. Otherwise, exit the program.
         //
         if ( wasCreated )
         {
            Console::WriteLine( L"Created the named event." );
         }
         else
         {
            Console::WriteLine( L"Unable to create the event." );
            return;
         }
      }
      else if ( unauthorized )
      {
         // Open the event to read and change the access control
         // security. The access control security defined above
         // allows the current user to do this.
         //
         try
         {
            ewh = EventWaitHandle::OpenExisting( ewhName, 
               static_cast<EventWaitHandleRights>(
                  EventWaitHandleRights::ReadPermissions |
                  EventWaitHandleRights::ChangePermissions) );
            
            // Get the current ACL. This requires
            // EventWaitHandleRights.ReadPermissions.
            EventWaitHandleSecurity^ ewhSec = ewh->GetAccessControl();
            String^ user = String::Concat( Environment::UserDomainName, L"\\",
               Environment::UserName );
            
            // First, the rule that denied the current user
            // the right to enter and release the event must
            // be removed.
            EventWaitHandleAccessRule^ rule = gcnew EventWaitHandleAccessRule(
               user,
               static_cast<EventWaitHandleRights>(
                  EventWaitHandleRights::Synchronize |
                  EventWaitHandleRights::Modify),
               AccessControlType::Deny );
            ewhSec->RemoveAccessRule( rule );
            
            // Now grant the user the correct rights.
            //
            rule = gcnew EventWaitHandleAccessRule( user,
               static_cast<EventWaitHandleRights>(
                  EventWaitHandleRights::Synchronize |
                  EventWaitHandleRights::Modify),
               AccessControlType::Allow );
            ewhSec->AddAccessRule( rule );
            
            // Update the ACL. This requires
            // EventWaitHandleRights.ChangePermissions.
            ewh->SetAccessControl( ewhSec );
            Console::WriteLine( L"Updated event security." );
            
            // Open the event with (EventWaitHandleRights.Synchronize
            // | EventWaitHandleRights.Modify), the rights required
            // to wait on and signal the event.
            //
            ewh = EventWaitHandle::OpenExisting( ewhName );
         }
         catch ( UnauthorizedAccessException^ ex ) 
         {
            Console::WriteLine( L"Unable to change permissions: {0}",
               ex->Message );
            return;
         }

      }
      
      // Wait on the event, and hold it until the program
      // exits.
      //
      try
      {
         Console::WriteLine( L"Wait on the event." );
         ewh->WaitOne();
         Console::WriteLine( L"Event was signaled." );
         Console::WriteLine( L"Press the Enter key to signal the event and exit." );
         Console::ReadLine();
      }
      catch ( UnauthorizedAccessException^ ex ) 
      {
         Console::WriteLine( L"Unauthorized access: {0}", ex->Message );
      }
      finally
      {
         ewh->Set();
      }
   }
};

int main()
{
   Example::Main();
}
using System;
using System.Threading;
using System.Security.AccessControl;

internal class Example
{
    internal static void Main()
    {
        const string ewhName = "EventWaitHandleExample5";

        EventWaitHandle ewh = null;
        bool doesNotExist = false;
        bool unauthorized = false;

        // The value of this variable is set by the event
        // constructor. It is true if the named system event was
        // created, and false if the named event already existed.
        //
        bool wasCreated;

        // Attempt to open the named event.
        try
        {
            // Open the event with (EventWaitHandleRights.Synchronize
            // | EventWaitHandleRights.Modify), to wait on and 
            // signal the named event.
            //
            ewh = EventWaitHandle.OpenExisting(ewhName);
        }
        catch (WaitHandleCannotBeOpenedException)
        {
            Console.WriteLine("Named event does not exist.");
            doesNotExist = true;
        }
        catch (UnauthorizedAccessException ex)
        {
            Console.WriteLine("Unauthorized access: {0}", ex.Message);
            unauthorized = true;
        }

        // There are three cases: (1) The event does not exist.
        // (2) The event exists, but the current user doesn't 
        // have access. (3) The event exists and the user has
        // access.
        //
        if (doesNotExist)
        {
            // The event does not exist, so create it.

            // Create an access control list (ACL) that denies the
            // current user the right to wait on or signal the 
            // event, but allows the right to read and change
            // security information for the event.
            //
            string user = Environment.UserDomainName + "\\"
                + Environment.UserName;
            EventWaitHandleSecurity ewhSec = 
                new EventWaitHandleSecurity();

            EventWaitHandleAccessRule rule = 
                new EventWaitHandleAccessRule(user, 
                    EventWaitHandleRights.Synchronize | 
                    EventWaitHandleRights.Modify, 
                    AccessControlType.Deny);
            ewhSec.AddAccessRule(rule);

            rule = new EventWaitHandleAccessRule(user, 
                EventWaitHandleRights.ReadPermissions | 
                EventWaitHandleRights.ChangePermissions, 
                AccessControlType.Allow);
            ewhSec.AddAccessRule(rule);

            // Create an EventWaitHandle object that represents
            // the system event named by the constant 'ewhName', 
            // initially signaled, with automatic reset, and with
            // the specified security access. The Boolean value that 
            // indicates creation of the underlying system object
            // is placed in wasCreated.
            //
            ewh = new EventWaitHandle(true, 
                EventResetMode.AutoReset, 
                ewhName, 
                out wasCreated, 
                ewhSec);

            // If the named system event was created, it can be
            // used by the current instance of this program, even 
            // though the current user is denied access. The current
            // program owns the event. Otherwise, exit the program.
            // 
            if (wasCreated)
            {
                Console.WriteLine("Created the named event.");
            }
            else
            {
                Console.WriteLine("Unable to create the event.");
                return;
            }
        }
        else if (unauthorized)
        {
            // Open the event to read and change the access control
            // security. The access control security defined above
            // allows the current user to do this.
            //
            try
            {
                ewh = EventWaitHandle.OpenExisting(ewhName, 
                    EventWaitHandleRights.ReadPermissions | 
                    EventWaitHandleRights.ChangePermissions);

                // Get the current ACL. This requires 
                // EventWaitHandleRights.ReadPermissions.
                EventWaitHandleSecurity ewhSec = ewh.GetAccessControl();
                
                string user = Environment.UserDomainName + "\\"
                    + Environment.UserName;

                // First, the rule that denied the current user 
                // the right to enter and release the event must
                // be removed.
                EventWaitHandleAccessRule rule = 
                    new EventWaitHandleAccessRule(user, 
                        EventWaitHandleRights.Synchronize | 
                        EventWaitHandleRights.Modify, 
                        AccessControlType.Deny);
                ewhSec.RemoveAccessRule(rule);

                // Now grant the user the correct rights.
                // 
                rule = new EventWaitHandleAccessRule(user, 
                    EventWaitHandleRights.Synchronize | 
                    EventWaitHandleRights.Modify, 
                    AccessControlType.Allow);
                ewhSec.AddAccessRule(rule);

                // Update the ACL. This requires
                // EventWaitHandleRights.ChangePermissions.
                ewh.SetAccessControl(ewhSec);

                Console.WriteLine("Updated event security.");

                // Open the event with (EventWaitHandleRights.Synchronize 
                // | EventWaitHandleRights.Modify), the rights required
                // to wait on and signal the event.
                //
                ewh = EventWaitHandle.OpenExisting(ewhName);

            }
            catch (UnauthorizedAccessException ex)
            {
                Console.WriteLine("Unable to change permissions: {0}",
                    ex.Message);
                return;
            }

        }

        // Wait on the event, and hold it until the program
        // exits.
        //
        try
        {
            Console.WriteLine("Wait on the event.");
            ewh.WaitOne();
            Console.WriteLine("Event was signaled.");
            Console.WriteLine("Press the Enter key to signal the event and exit.");
            Console.ReadLine();
        }
        catch (UnauthorizedAccessException ex)
        {
            Console.WriteLine("Unauthorized access: {0}", ex.Message);
        }
        finally
        {
            ewh.Set();
        }
    }
}
Imports System.Threading
Imports System.Security.AccessControl

Friend Class Example

    <MTAThread> _
    Friend Shared Sub Main()
        Const ewhName As String = "EventWaitHandleExample5"

        Dim ewh As EventWaitHandle = Nothing
        Dim doesNotExist as Boolean = False
        Dim unauthorized As Boolean = False

        ' The value of this variable is set by the event
        ' constructor. It is True if the named system event was
        ' created, and False if the named event already existed.
        '
        Dim wasCreated As Boolean

        ' Attempt to open the named event.
        Try
            ' Open the event with (EventWaitHandleRights.Synchronize
            ' Or EventWaitHandleRights.Modify), to wait on and 
            ' signal the named event.
            '
            ewh = EventWaitHandle.OpenExisting(ewhName)
        Catch ex As WaitHandleCannotBeOpenedException
            Console.WriteLine("Named event does not exist.")
            doesNotExist = True
        Catch ex As UnauthorizedAccessException
            Console.WriteLine("Unauthorized access: {0}", ex.Message)
            unauthorized = True
        End Try

        ' There are three cases: (1) The event does not exist.
        ' (2) The event exists, but the current user doesn't 
        ' have access. (3) The event exists and the user has
        ' access.
        '
        If doesNotExist Then
            ' The event does not exist, so create it.

            ' Create an access control list (ACL) that denies the
            ' current user the right to wait on or signal the 
            ' event, but allows the right to read and change
            ' security information for the event.
            '
            Dim user As String = Environment.UserDomainName _ 
                & "\" & Environment.UserName
            Dim ewhSec As New EventWaitHandleSecurity()

            Dim rule As New EventWaitHandleAccessRule(user, _
                EventWaitHandleRights.Synchronize Or _
                EventWaitHandleRights.Modify, _
                AccessControlType.Deny)
            ewhSec.AddAccessRule(rule)

            rule = New EventWaitHandleAccessRule(user, _
                EventWaitHandleRights.ReadPermissions Or _
                EventWaitHandleRights.ChangePermissions, _
                AccessControlType.Allow)
            ewhSec.AddAccessRule(rule)

            ' Create an EventWaitHandle object that represents
            ' the system event named by the constant 'ewhName', 
            ' initially signaled, with automatic reset, and with
            ' the specified security access. The Boolean value that 
            ' indicates creation of the underlying system object
            ' is placed in wasCreated.
            '
            ewh = New EventWaitHandle(True, _
                EventResetMode.AutoReset, ewhName, _
                wasCreated, ewhSec)

            ' If the named system event was created, it can be
            ' used by the current instance of this program, even 
            ' though the current user is denied access. The current
            ' program owns the event. Otherwise, exit the program.
            ' 
            If wasCreated Then
                Console.WriteLine("Created the named event.")
            Else
                Console.WriteLine("Unable to create the event.")
                Return
            End If

        ElseIf unauthorized Then

            ' Open the event to read and change the access control
            ' security. The access control security defined above
            ' allows the current user to do this.
            '
            Try
                ewh = EventWaitHandle.OpenExisting(ewhName, _
                    EventWaitHandleRights.ReadPermissions Or _
                    EventWaitHandleRights.ChangePermissions)

                ' Get the current ACL. This requires 
                ' EventWaitHandleRights.ReadPermissions.
                Dim ewhSec As EventWaitHandleSecurity = _
                    ewh.GetAccessControl()
                
                Dim user As String = Environment.UserDomainName _ 
                    & "\" & Environment.UserName

                ' First, the rule that denied the current user 
                ' the right to enter and release the event must
                ' be removed.
                Dim rule As New EventWaitHandleAccessRule(user, _
                    EventWaitHandleRights.Synchronize Or _
                    EventWaitHandleRights.Modify, _
                    AccessControlType.Deny)
                ewhSec.RemoveAccessRule(rule)

                ' Now grant the user the correct rights.
                ' 
                rule = New EventWaitHandleAccessRule(user, _
                    EventWaitHandleRights.Synchronize Or _
                    EventWaitHandleRights.Modify, _
                    AccessControlType.Allow)
                ewhSec.AddAccessRule(rule)

                ' Update the ACL. This requires
                ' EventWaitHandleRights.ChangePermissions.
                ewh.SetAccessControl(ewhSec)

                Console.WriteLine("Updated event security.")

                ' Open the event with (EventWaitHandleRights.Synchronize 
                ' Or EventWaitHandleRights.Modify), the rights required
                ' to wait on and signal the event.
                '
                ewh = EventWaitHandle.OpenExisting(ewhName)

            Catch ex As UnauthorizedAccessException
                Console.WriteLine("Unable to change permissions: {0}", _
                    ex.Message)
                Return
            End Try

        End If

        ' Wait on the event, and hold it until the program
        ' exits.
        '
        Try
            Console.WriteLine("Wait on the event.")
            ewh.WaitOne()
            Console.WriteLine("Event was signaled.")
            Console.WriteLine("Press the Enter key to signal the event and exit.")
            Console.ReadLine()
        Catch ex As UnauthorizedAccessException
            Console.WriteLine("Unauthorized access: {0}", _
                ex.Message)
        Finally
            ewh.Set()
        End Try
    End Sub 
End Class 

Hinweise

Der Benutzer muss über EventWaitHandleRights.ChangePermissions Rechte verfügen, um diese Methode aufzurufen, und das Ereignis muss mit dem EventWaitHandleRights.ChangePermissions-Flag geöffnet worden sein.The user must have EventWaitHandleRights.ChangePermissions rights to call this method, and the event must have been opened with the EventWaitHandleRights.ChangePermissions flag.

Gilt für:

Siehe auch