I am using the service controller in C++ to manage a windows service.
I can use the StartService( ) and ControlService( ) functions to start and stop the service.
However, is there a standard way to wait for the service to actually start and stop?
I could obviously loop calling QueryServiceStatusEx( ) and wait until the status is Running or Stopped respectively.
Is there a neater way of achieving the same?
Thanks.
Afaik Service start and stop create windows event log events. Maybe you could install a handler for those and wait for the event from your application. If your application is also a service mark it as depending on the 3rd party service then you should not have to wait on it.
In C# you can do this using ServiceController.WaitForStatus. You could do it this way (one line of code) and wrap the C# within your C++ code.
Otherwise, you will likely be futzing around with WMI (Win32_Service class) or the Event Log.
Related
I need to listen for touch events from a specific app(in blackberry 10 os). I am planning to write another app which does this. Is this possible?
APP A- the app which exists
APP B- The app i am going to write
what sort of modification do i need to do for the APPA to make this possible.
In the Cascades environment touch events are passed as SIGNALS which are received by SLOTS. This message passing implementation is bound to the threading model and does not have a direct inter process counterpart. Theoretically you could implement something on top of the QNX message passing system, or on top of BlackBerry Platform Services (BPS). This might be necessary if you need the kind of performance available within a single application.
The other option is to use the invokation API that BlackBerry provides in Cascades. This is a very flexible inter-process communications protocol but is inherently synchronous. Normally UI focus moves from the invoking process to the invoked process, this does not sound like what you want. The invoked process can return immediately after receiving the invokation and before posting any UI elements, but there is still the overhead of launching the invoked process, at least in the first instance, and context switching in other instances.
It might be more fruitful to be more specific about what you are really trying to accomplish.
I would start looking at Starting a process if you haven't all-ready.
Probably NOT !
Your app can only listen to touch events in your app and cannot spy on other apps.
Not possible. This would be a major security flaw...
I want to make a tool that runs on win32 to monitor our online game servers. The servers actually are .exe files. I need to know whether they have crashed so I can restart them. Therefore, the tool will have 2 main features:
Frequently check a list of the server programs to see whether they are running or not
Reopen the executable of any server that has crashed
Does anyone have any idea or knows an API to start with?
If you're in Win32, you can start out with C# using System.Diagnostics
using System.Diagnostics;
Then get a process list:
Process[] processlist = Process.GetProcesses();
foreach(Process theprocess in processlist){
Console.WriteLine(“Process: {0} ID: {1}”, theprocess.ProcessName, theprocess.Id);
}
And from there it's up to you what you want to do with the info.
Game servers should produce logs. You should make a service / cron job to monitor the logs. Depends on the contents of logs, your service should act respective actions, e.g. restart service, trigger alarms, etc.
I realize that this is not exactly what you asked for, but what about doing the monitoring with a fully-fledged monitoring tool such as Nagios? You would of course have to "teach" the monitoring tool about the processes that shall be monitored but you would also profit from its more advanced functions. In the case of Nagios, for example, these would comprise automatic e-mail notifications, an online dashboard of process status, notifications via SMS etc.
You should start the game servers using CreateProcess or similar in the win32 api.
You will get back a process handle in the lpProcessInformation parameter.
You can use WaitForSingleObject to WaitForMultipleObjects to wait until that handle is notified which will happen when the process terminates for any reason.
I have a service which constantly checks some application and assures that it wasn't closed. If this app closed - service launches it again.
The problem starts when user decides to log off the session. During logoff all applications are closing including the mine one. But the service is still running and constantly trying to start it again.
The questions is how to notify the service that user is going to log off and the application doesn't need to be restarted anymore? I've tried to make it using SERVICE_CONTROL_SESSIONCHANGE notification. But in accordance to MSDN they come to services when all apps already closed and logging off procedure completed. It is too late for me. Is there any way to programmatically find out that current session is in process of logging off?
My service launched under LocalSystem account.
Thanks.
p.s. I don't have the access to application source code. The goal need to be achieved without modifying it.
Have your service run two applications: the one it is a watchdog for, and a second one which you implement yourself. This second one can then respond to the log-off event by sending a message to the service (a la David Heffernan's answer), and the service will then know not to restart the watched job.
Open a communication channel between your app and your service and arrange for the app to tell the service that it is closing because of a logoff event.
You may not have access to the source code of the executable, but that doesn't mean that you can't affect the process. For instance, you could inject a DLL. Using SetWindowsHookEx, you'd catch the WM_ENDSESSION sent to the apps main window.
Why don't you create your service under the user that is running the App and tell it to startup automatic? In this case you should get the SERVICE_CONTROL_SHUTDOWN message when your user is logging off since the service would also be terminated.
How Can I execute a function when Windows shutdown. Here is my scenario, I am mounting a drive using WNetAddConnection2 function in my application. Now I want user to set the option if the drive will be mounted on next system startup or not.
If he selects , not to mount on next startup , then I need to remove the drive using WNetCancelConnection2 , but this should only happen when user shutdown the system.
I can only think of only solution. Create a service which will check the user option and then decide whether to mount the drive or not.
Are there any other ways to go ahead with it?
If you have a main window (even an invisible one) that can process messages, you can handle the WM_ENDSESSION message.
See: http://msdn.microsoft.com/en-us/library/aa376889(v=VS.85).aspx
If you can make your app into a Windows service (or have your app communicate state with one that you provide) you can perform required actions on receipt of SERVICE_CONTROL_SHUTDOWN in your service control handler function. This would decouple your app that handles user interaction from the shutdown handling, which requires something to be running all the time (what if the user logs off?).
explorer.exe is the GUI process of windows which usually only gets shut down if Windows shuts down (exceptions have to be made for certain error conditions). You could listen on the WM_DESTROY window message for the process ID of explorer.exe and dismount then.
The way I can think of is to:
Register your program to auto Start up (when PC starts). Here's a tutorial on howto.
Store the user option (as mentioned above) in a repository or registry (if you know how). When your app would have started, you can read your registry and act accordingly.
For shutdown, your application will have to hook itself on a SystemEvent to detect shutdown (then you can act accordingly). Here's an example on howto (C#). For C++, you can listen to WM_ENDSESSION message.
I hope that my 2 cents can help you.
I am wanting to write some web services using WCF.
I would like to have a "thread pool" in my web service.
For example, I have nearly 6gb of data I need to manipulate.
I would like the client to call an operation on the webservice and have a new task or thread created. The client is able to call a ListRunningTasks(); and have the webservice return a list of tasks. The client should be able to forcefully kill a task if it is taking too long e.g. KillTask(int taskID); or something. I have previously done some threading, but not inside WCF or a service that doesn't have state. Is this possible? If so, how would one go about implementing such a thing? Any reading, links or suggestions would be great.
Thanks, Mike.
One possible solution:
Implement explicit queues for your outstanding tasks taking into consideration that they take that long (20-30mins as you wrote).
Build a custom component to manage those queues e.g. you might even want capabilities to persist them, resume work when you restart the service etc.
Have explicitly created worker threads that pickup work from those queues.
Implement a WCF service to make your queue manager available to external systems.
Thread pools are more designed to process a high volume of short-running tasks.
You should consider using Windows Workflow Foundation to create such services. A state machine workflow can be exposed as a service in such a way that when method A is called, it will start the workflow (task), after which methods can be called to stop, suspend, or query the running task. WF will handle the state transitions, preventing illegal state changes, and making sure that new tasks are only spun up as necessary.
Note that WF will handle the threading issues for you in an almost transparent manner.