ServiceManager

This article applies to Windows only.

See also: Multiplatform Programming Guide

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ServiceManager

For Windows, the fcl-extra package contains a unit called ServiceManager.

The example below checks whether the SamSs (Security Accounts Manager; should always be running) service is running. (Command line equivalent sc query samss).

Service Name

Please note that if you develop your own service using the Lazdaemon package, the service name you must use is important. While the commands NET START and NET STOP use the service display name, the command SC and the code below use the service internal name. The display name is the one given to the property "DisplayName" of the item created in the DaemonDefs items. The service name is the property "Name" of the same item. The display name is the one currently displayed in the Name column by the MS services manager applet (services.msc) Let's use an example to clarify this. Assume you have written a service application called myService.exe in which there is one item in the DaemonDefs. The item has a name of "MyServ" and the associated "DisplayName" property has the value of "Internal build service". Using the command line as administrator you can:

Service management using console

You will need: Microsoft .NET Framework 4.5.2 (Web Installer) for Windows Vista SP2, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2008 SP2 Windows Server 2008 R2 SP1, Windows Server 2012 and Windows Server 2012 R2

You have to get the support of .NET SDK Command prompt for install the service into your local machine. 1. Call to SDK Command prompt, follow Start>All Programs>Microsoft .NET Framework SDK v2.0>SDK Command prompt

Install the service:

\your\path\to\application\myService.exe --install 
rem .... or /install, -install works too

Activate the service: In these commands, do not forget double quotes when multiple words are needed!

net start "Internal build service"
rem .... or alternatively:
sc start "MyServ"

To stop the service:

net stop '''"Internal build service"'''
rem ... or alternatively 
sc stop "'''MyServ'''"

Code example

Given the above, the code snippet to call the function below would be in our case:

if IsServiceRunning('MyServ') then

Example program:

program ServiceTest;
// Check if a certain process is running.
{$mode objfpc}{$H+}
uses
  Classes,
  SysUtils,
  ServiceManager,
  JwaWinSvc {for services declarations};

function IsServiceRunning(ServiceName: string): boolean;
  {description Checks if a Windows service is running}
var
  Services: TServiceManager;
  ServiceStatus: TServiceStatus;
begin
  //Check for existing services
  //equivalent to sc query <servicename>
  Services := TServiceManager.Create(nil);
  try
    try
      Services.Acces := SC_MANAGER_CONNECT; //Note typo in property.
      //We don't need more access permissions than this; by default
      //the servicemanager is trying to get all access
      Services.Connect; //Now connect with requested access level
      Services.GetServiceStatus(ServiceName, ServiceStatus);
      Result := (ServiceStatus.dwCurrentState = SERVICE_RUNNING);
      Services.Disconnect;
    except
      on E: EServiceManager do
      begin
        // A missing service might throw a missing handle exception? No?
        {LogOutput('Error getting service information for ' + ServiceName +
                   '. Technical details: ' + E.ClassName + '/' + E.Message); }
        Result := False;
        raise; //rethrow original exception
      end;
      on E: Exception do
      begin
       {LogOutput('Error getting service information for ' + ServiceName +
                  '. Technical details: ' + E.ClassName + '/' + E.Message); }
        Result := False;
        raise; //rethrow original exception
      end;
    end;
  finally
    Services.Free;
  end;
end;

const
  ServiceToTest = 'SamSs';

//Security Accounts Manager, should be running, at least on Vista
begin
  WriteLn('Starting test for ' + ServiceToTest + ' service.');
  if IsServiceRunning(ServiceToTest) then
    WriteLn('The ' + ServiceToTest + ' service is running')
  else
    WriteLn('The ' + ServiceToTest + ' service is not running');
end.

See also

• Daemons and Services
• TServiceManager