Create a Web Service Method to Manage a NT Service

Introduction

Recently, I created a mobile application-Siccolo that allows me to manage SQL Servers by using web services hosted on public domain (see more information here about how to develop a mobile management tool).

Among other problems, I had to be able to restart SQL Server service on machine(s) other than web service host from within web method. And I wanted not just to stop and start MSSQLSERVER service, but also restart all the services that are dependent on MSSQLSERVER service, e.g. SQL Server Agent, Crystal Reports Engine, CRM Security Service, etc.

The code presented here allows to restart (or just stop, or start) NT Service.

Background (optional, but needed)

My "managing" web service is hosted under SSL with "Integrated Windows" authentication being set. Therefore, mobile application is required to pass network credentials. And this is needed to be able to remotely access SQL Server machine to control MSSQLSERVER service.

Using the Code

The components used are as follows:

• serviceprocessor.asmx.cs - Web service interface
• NTServiceInfo.cs - A small "wrapper" to control NT Service

Let's see how to restart SQL Server service. .NET provides just the tool for this task - System.ServiceProcess.ServiceController class. To create an instance of System.ServiceProcess.ServiceController:

// C# //
...
System.ServiceProcess.ServiceController <CODE>Service;
if (this.m_MachineName!="")
    {Service = new ServiceController(this.m_ServiceName, this.m_MachineName ) ;}
else
{Service = new ServiceController(this.m_ServiceName ) ;}
...

And the fact that authentication (Integrated Windows authentication or Basic) is in place on IIS, actually helps here. In order to be able to access service(s) on a different machine than web service host, web service needs to "assume" an identity of authenticated user. Normally, web service is running under ASP.NET user with minimum privileges and I needed to impersonate authenticated user with the web service.

On the server side, to retrieve authenticated user, we need to use System.Web.Services.WebService.User and then impersonate: and code does just that - "Impersonates the user represented by the WindowsIdentity object."

// C# //
...
    
System.Security.Principal.WindowsImpersonationContext <CODE>impersonationContext;
        impersonationContext = 
            ((System.Security.Principal.WindowsIdentity)User.Identity).Impersonate();
... 

To enumerate dependent services - System.ServiceProcess.ServiceController has DependentServices property:

// C# //
...
foreach (System.ServiceProcess.ServiceController <CODE>dependent_service 
                        in Service.DependentServices)
{    
    ...
}
...    

To handle recursive stopping and starting, I added small "wrapper" NTServiceInfo class:

// NTServiceInfo :
public bool RestartServervice(WindowsPrincipal User, 
                bool ToDebug, 
                out string ErrorInfo)
{
    try
    {
        ErrorInfo ="";
        
        if (this.StopService(User, ToDebug, out ErrorInfo))
        {
            if (this.StartService(User, ToDebug, out ErrorInfo))
            {return true;}
            else{return false;}
        }
        else
        {return false;}
    }
    catch (Exception ex_restart_service)
    {
        ErrorInfo = "Restart Service [" + this.m_ServiceName + "] 
			[" + ex_restart_service.Message + "]";
        return false;
    }
}

Where StopService() and StartService() methods are:

// NTServiceInfo :
public bool StopService(WindowsPrincipal User, 
                bool ToDebug, 
                out string ErrorInfo)
    {
        try
        {
            System.Security.Principal.WindowsImpersonationContext impersonationContext;
                impersonationContext = 
                    ((System.Security.Principal.WindowsIdentity)
				User.Identity).Impersonate();

            System.ServiceProcess.ServiceController Service;
            if (this.m_MachineName!="")
            {Service = new ServiceController(this.m_ServiceName, this.m_MachineName ) ;}
            else
            {Service = new ServiceController(this.m_ServiceName ) ;}

            //stop all the Dependent services...
            foreach (System.ServiceProcess.ServiceController dependent_service 
                            in Service.DependentServices)
            {                    
                switch ( dependent_service.Status)
                {
                    case ServiceControllerStatus.Stopped:
                        //already stopped...nothing to do
                        break;

                    case ServiceControllerStatus.StopPending:
                        dependent_service.WaitForStatus(ServiceControllerStatus.Stopped);
                        break;

                    default:
                        Service.Stop();
                        Service.WaitForStatus(ServiceControllerStatus.Stopped);
                        break;
                }
            }

            //stop main service...
            switch ( Service.Status)
            {
                case ServiceControllerStatus.Stopped:
                    //already stopped...nothing to do
                    break;

                case ServiceControllerStatus.StopPending:
                    Service.WaitForStatus(ServiceControllerStatus.Stopped);
                    break;

                default:
                    // *-****************************************************************
                    //check all dependent services?
                    foreach (System.ServiceProcess.ServiceController dependent_service 
                                        in Service.DependentServices)
                    {                    
                        switch ( dependent_service.Status)
                        {
                            case ServiceControllerStatus.Stopped:
                                //already stopped...nothing to do
                                break;

                            case ServiceControllerStatus.StopPending:
                            dependent_service.WaitForStatus
				(ServiceControllerStatus.Stopped);
                                break;

                            default:
                                Service.Stop();
                                Service.WaitForStatus(ServiceControllerStatus.Stopped);
                                break;
                        }                           

                        }

                        if ( !Service.CanStop )
                        {
                            throw new Exception ("Cannot stop service [" + 
                                    this.m_ServiceName + "]");
                        }
                        Service.Stop();
                        Service.WaitForStatus(ServiceControllerStatus.Stopped);
                        break;
                }

                Service.Close();

                impersonationContext.Undo();

                ErrorInfo="";
                return true;
            }

        catch (Exception ex_stop_service)
        {
            ErrorInfo = ex_stop_service.Message;
            return false;
        }
    }

    public bool StartService(WindowsPrincipal User, 
                bool ToDebug, 
                out string ErrorInfo)
    {
        try
        {
            System.Security.Principal.WindowsImpersonationContext impersonationContext;
            impersonationContext = 
                ((System.Security.Principal.WindowsIdentity)User.Identity).Impersonate();

            System.ServiceProcess.ServiceController Service;
            if (this.m_MachineName!="")
            {Service = new ServiceController(this.m_ServiceName, this.m_MachineName ) ;}
            else
            {Service = new ServiceController(this.m_ServiceName ) ;}
            
            switch ( Service.Status)
            {
                case ServiceControllerStatus.Stopped:
                    Service.Start();
                    Service.WaitForStatus(ServiceControllerStatus.Running);
                    break;

                case ServiceControllerStatus.StopPending:
                    //wait for it to stop
                    Service.WaitForStatus(ServiceControllerStatus.Stopped);
                    //... and then start
                    Service.Start();
                    Service.WaitForStatus(ServiceControllerStatus.Running);
                    break;

                case ServiceControllerStatus.StartPending:
                    //nothing to do...just wait
                    Service.WaitForStatus(ServiceControllerStatus.Running);
                    break;

                case ServiceControllerStatus.Running:
                    //nothing to do.already running...
                    break;
                
                default:
                    Service.Start();
                    Service.WaitForStatus(ServiceControllerStatus.Running);
                    break;
            }

            //start all the Dependent services...
            foreach (System.ServiceProcess.ServiceController dependent_service 
                            in Service.DependentServices)
            {
                
                switch (dependent_service.Status )
                {
                    case ServiceControllerStatus.StartPending:
                        //just wait for it to start
                        dependent_service.WaitForStatus (ServiceControllerStatus.Running);
                        break;

                    case ServiceControllerStatus.Running:
                        //already running.nothing to do
                        break;

                    default:
                        NTServiceInfo si = 
                                new NTServiceInfo( dependent_service.ServiceName, 
					this.m_MachineName);
                        if ( !si.StartService(User, ToDebug, out ErrorInfo))
                        {
                            throw new Exception ("Failed to start Dependent Service [" +  
                                            dependent_service.ServiceName + 
                                            "] - Error [" + ErrorInfo + "]") ;
                        }
                        break;
                }
            }
            
            Service.Close();

            impersonationContext.Undo();

            ErrorInfo="";
            return true;
        }
        catch (Exception ex_start_service)
        {
            ErrorInfo = ex_start_service.Message;
            return false;
        }
    }

So, after all, web method looks like this:

[WebMethod]
    public bool RestartSQLServerService(string RemoteServerAddress,
                    out string NewServiceStatus, 
                    out string ErrorInfo )
    {
        try
        {
            string ToDebugSetting = 
                System.Configuration.ConfigurationSettings.AppSettings.Get("DebugMode");
            bool ToDebug = (ToDebugSetting!="");

            string NTServiceName = "MSSQLSERVER";

            ErrorInfo="";
            NewServiceStatus ="";

            System.Security.Principal.WindowsImpersonationContext impersonationContext;
                impersonationContext = 
                    ((System.Security.Principal.WindowsIdentity)
					User.Identity).Impersonate();
            
            NTServiceInfo si = new NTServiceInfo(NTServiceName, RemoteServerAddress);

            if ( ! si.RestartServervice ((WindowsPrincipal) 
				this.User,ToDebug,  out ErrorInfo))
            {return false;}

            NewServiceStatus =  si.ServiceStatus();

            impersonationContext.Undo();
                
            ErrorInfo = "";
            return true;
        }
        catch (Exception ex_get_service_info)
        {
            NewServiceStatus ="";
            ErrorInfo = ex_get_service_info.Message;
            return false;
        }
    }

Or, to make functionality more generic:

[WebMethod]
        public bool RestartNTService(string RemoteServerAddress , 
                                    string NTServiceName, 
                                    out string NewServiceStatus  , 
                                    out bool CanStop, 
                                    out bool CanPauseAndContinue,
                                    out string ErrorInfo )
        {    
            try
            {
        
                string ToDebugSetting = 
                 System.Configuration.ConfigurationSettings.AppSettings.Get("DebugMode");
                bool ToDebug = (ToDebugSetting!="");

                ErrorInfo="";
                NewServiceStatus ="";
                CanStop = false;
                CanPauseAndContinue = false;

                System.Security.Principal.WindowsImpersonationContext 
						impersonationContext;
                impersonationContext = 
                    ((System.Security.Principal.WindowsIdentity)
					User.Identity).Impersonate();
            
                NTServiceInfo si = new NTServiceInfo(NTServiceName, RemoteServerAddress);

                if ( ! si.RestartServervice ((WindowsPrincipal) 
				this.User,ToDebug,  out ErrorInfo))
                {return false;}

                NewServiceStatus =  si.ServiceStatus();
                CanStop = si.CanStop();
                CanPauseAndContinue = si.CanPauseAndContinue();

                impersonationContext.Undo();

                ErrorInfo = "";
                return true;
            }
            catch (Exception ex_get_service_info)
            {
                NewServiceStatus ="";
                CanStop = false;
                CanPauseAndContinue = false;
                ErrorInfo = ex_get_service_info.Message;
                return false;
            }
        }

Points of Interest

If you would like to read more on this store - please take a look at Siccolo - Free Mobile Management Tool For SQL Server and the full article at How to Develop Mobile Management Tool.

History

No improvements so far. Nearly perfect.