I need to monitor GPS Coordinates changes at every 15 min and take action based on that. as per bada developer guide report "only one application allowed to run at a time if another application try to run first one is closed" .so that how do i monitor GPS coordinates without interruption from other applications. how do i keep my application running at all times
UPDATE
bada agent applications
alt text http://www.freeimagehosting.net/uploads/1c8b9c134c.jpg
It appears that the Bada environment is neither designed nor suited for your application. QUoting Samsung: "According to one of the fundamentals of bada development, bada devices do not support daemon (agent) applications. "
I came to understand that Agent application functionality still not implemented for 3rd party applications, it is reserved for internal use only. And there is no daemon like application functionalities.
We can use multitasking inside user application but not multiple user applications due to single application policy.
Bada platform is not limited to single tasking, bada allows multitasking between base applications such as music player, calendar and so on.
So continuously monitoring GPS coordinates is difficult
Related
I have done a lot of searching to find a way to start a GUI application from a windows service on Windows 7. Most of what I have found is that with Windows 7 services now run in a separate user session and can not display any graphical interface to the current user. I'm wondering is there is any kind of workaround or different way of accomplishing something like this? Can the service start a process in a different user session?
This change was made for a reason and not simply to annoy developers. The correct approach is to put your UI in a different program and communicate with the session through a pipe, or some other IPC mechanism. The recommendation that services do not present UI is more than 10 years old now.
You should really try to follow these rules, even though it may seem inconvenient to begin with. On the plus side you will enjoy the benefit of keeping your service logic and UI logic separate
If your services runs under the LOCALSYSTEM account then you can check "Allow service to interact with desktop", for the benefit of legacy services that would fail if they could not show UI. But it won't help you anyway because the UI will show in session 0 where it is never seen!
I recommend you take a read of the official Microsoft document describing session 0 isolation.
There is a way to do this.
If you need to show a simple message box you can use the WTSSendMessage Routine.
If you need a complex UI elements you can put it in a separate program and you need to use CreateProcessAsUser Routine.
In this sample provided by microsoft you can see the process.
http://blogs.msdn.com/b/codefx/archive/2010/11/26/all-in-one-windows-service-code-samples.aspx
Windows 7 introduced what is called "Session 0 isolation" that in practice means that every service (except system services) run in a separate non-interactive session. For this reason you cannot directly create a GUI from within the service, except if you run in legacy mode by flagging the Interact With Destop option, which is not good if you plan to run your service for some years in the future.
As David Heffernan said, the best is to use a client-server architecture. WCF makes it easy to communicate with named pipes.
This page is a good starting point to read about Session 0 Isolation and this white paper is also very good.
I have a C++ Win32 application that was written as a Windows GUI project, and now I'm trying to figure out to make it into a Service / GUI hybrid. I understand that a Windows Service cannot / should not have a user interface. But allow me to explain what I have so far and what I'm shooting for.
WHAT I HAVE NOW is a windows application. When it is run it places an icon in the system tray that you can double-click on to open up the GUI. The purpose of this application is to process files located in a specified directory on a nightly schedule. The GUI consists of the following:
A button to start an unscheduled scan/process manually.
A button to open a dialog for modifying settings.
A List Box for displaying status messages sent from the processing thread.
A custom drawn window for displaying image data (the file processing includes the creation and saving of images).
A status bar - while a process is not running, it shows a countdown to the next scheduled scan. During a scan it also provides some status feedback, including a progress bar.
WHAT I'M SHOOTING FOR is a service that will run on boot-up and not require a user to login. This would consist of the scheduled file processing. However, when a user logs in I would still like the tray icon to be loaded and allow them to open up a GUI as I described above to monitor the current state of the service, change settings, start a scan manually, and monitor the progress of a scan.
I'm sure that I have seen applications like this - that function as a service even when I'm not logged in, but still give me a user interface to work with once I do log in.
I'm thinking that instead of having a single multi-threaded application that sends messages to the GUI thread from the processing thread, I need two applications - a Service to perform the processing and a GUI application to provide visual feedback from the Service and also send messages to the Service (for example, to start a scan manually). But I am new to Windows Services and have no idea how this is done.
It is also possible that I'm completely off base and a Service is not what I'm looking for at all.
Any help / ideas / suggestions would be greatly appreciated! Thank you.
You can't do this as a service.
You'll need to make your Windows Service as a normal service application. This will startup on system startup, and run the entire time the system is up.
You'd then make a completely separate GUI application, which "talks" to the service. This can be set to run when a user logs in, in the user's account.
In order to make them "talk" to each other, you'll need to use some form of IPC. Since these run on the same system (but in different accounts, typically), named pipes or sockets both work quite well.
There is a simple way of doing it.
You can’t have the service access any user’s session (session 1,2,3..) since services are isolated and can access session 0 only. This is a change from 2011.
You should write a win32 program to be launched by your service per each user who logs in using https://msdn.microsoft.com/en-us/library/windows/desktop/ms682429(v=vs.85).aspx
The service can continue performing any task that isn’t user specific.
What would be the simplest way for an application I'm writing to block all Internet access on a Windows machine?
More details:
Windows: XP or higher
Application: A basic Win32 app written in C/C++.
Blocking: It needs to be able to block and unblock at will, ideally in a way that the user can't easily reverse. (By, say, right clicking on a network connection icon in the system tray.) Also, ideally, I'd like the method it uses to allow access to be restored should the user restart Windows or reset the machine, though I'd also be willing to have the app auto launch with Windows and unblock access upon startup if the machine was reset while in a blocked state.
Internet access: Primarily, I'd like to block conventional browsers from hitting conventional http/https sites. Secondarily, it would be nice to block IM clients and client-side social networking apps. It would also be nice, but not required, to still allow local networking for file sharing, etc. (Note that only the first requirement is absolute.)
Final notes: This is not meant to be a security utility, nor will its relationship to the user be adversarial (as, for example, with a parental control utility) so it's not important for it to use a scheme that can't be worked around by a determined user. (Consider that I intend for a reboot or reset to clear the blocking. This means that any workaround a user might discover that would take more effort than this is okay.)
Thanks!
p.s. I suspect that the Windows Firewall API won't work for me because this needs to work for users that haven't enabled the firewall or don't have admin privileges, but I'll be thrilled if I'm corrected on this.
It sounds like you're intending to run applications that you don't want to access the internet. Perhaps you could run them inside a virtual machine such as VirtualBox with networking disabled.
You could do it with a Winsock SPI. The Windows SDK has a sample (under Samples\netds\winsock\lsp) which implements what is called a layered service provider which allows you to hook all the user mode functions provided by Winsock and reject/modify the calls to block network access or redirect traffic to different locations. All installed winsock applications will be affected, so in your code you could have policys for what applications can go out and the like and disabled/enable on the fly. Now a determined person could find ways around this but it would be a pain.
That said this isn't trivial to do but the sample should get you most of the way there.
You cannot effectively or practically write your tool with only a user mode application.
What you need to write is a network I/O stack filter driver. This done by writing a Windows Driver. This is different from a Windows Win32 application. Drivers run in kernel mode and applications run in user mode.
On Windows Vista and later, the kernel mode Network Programming Interface (NPI) is designed for this. This is the same API that Windows Firewalls use. These are sometimes called the Winsock kernel (WSK) APIs.
In effect, you are writing a network firewall (more or less)
here are some links
Introduction to Winsock Kernel (WSK)
Windows Core Networking Blog
The Network Programming Interface Docs on MSDN
Note, your will likely need at least two components
Your driver
A Graphical application that a person can use to control your tool
If you want to do any monitoring, you will likely need a user mode service that collects data from your driver. This works better than trying to do this in the driver. In general, you should do the minimal amount of work in the driver.
A few notes:
You need to be very conscious of security when writing this kind of software. This is very much non trivial. Software that is network facing has the highest security requirements.
Be cognizant of performance.
Your driver and/or service must be aware of the context of a calling application. This is also a security boundary. For example, an application not running as administrator should not be able to control your driver.
take a look at firewall sourcecodes
How are Massively Multiplayer Online RPG games built?
What server infrastructure are they built on? especially with so many clients connected and communicating in real time.
Do they manage with scripts that execute on page requests? or installed services that run in the background and manage communication with connected clients?
Do they use other protocols? because HTTP does not allow servers to push data to clients.
How do the "engines" work, to centrally process hundreds of conflicting gameplay events?
Thanks for your time.
Many roads lead to Rome, and many architectures lead to MMORPG's.
Here are some general thoughts to your bullet points:
The server infrastructure needs to support the ability to scale out... add additional servers as load increases. This is well-suited to Cloud Computing by the way. I'm currently running a large financial services app that needs to scale up and down depending on time of day and time of year. We use Amazon AWS to almost instantly add and remove virtual servers.
MMORPG's that I'm familiar with probably don't use web services for communication (since they are stateless) but rather a custom server-side program (e.g. a service that listens for TCP and/or UDP messages).
They probably use a custom TCP and/or UDP based protocol (look into socket communication)
Most games are segmented into "worlds", limiting the number of players that are in the same virtual universe to the number of game events that one server (probably with lots of CPU's and lots of memory) can reasonably process. The exact event processing mechanism depends on the requirements of the game designer, but generally I expect that incoming events go into a priority queue (prioritized by time received and/or time sent and probably other criteria along the lines of "how bad is it if we ignore this event?").
This is a very large subject overall. I would suggest you check over on Amazon.com for books covering this topic.
What server infrastructure are they built on? especially with so many clients connected and communicating in real time.
I'd guess the servers will be running on Linux, BSD or Solaris almost 99% of the time.
Do they manage with scripts that execute on page requests? or installed services that run in the background and manage communication with connected clients?
The server your client talks to will be a server running a daemons or service that sits idle listening for connections. For instances (dungeons), usually a new process is launched for each group, which would mean there is a dispatcher service somewhere mananging this (analogous to a threadpool)
Do they use other protocols? because HTTP does not allow servers to push data to clients.
UDP is the protocol used. It's fast as it makes no guarantees the packet will be received. You don't care if a bit of latency causes the client to lose their world position.
How do the "engines" work, to centrally process hundreds of conflicting gameplay events?
Most MMOs have zones which limit this to a certain amount of people. For those that do have 100s of people in one area, there is usually high latency. The server is having to deal with 100s of spells being sent its way, which it must calculate damage amounts for each one. For the big five MMOs I imagine there are teams of 10-20 very intelligent, mathematically gifted developers working on this daily and there isn't a MMO out there that has got it right yet, most break after 100 players.
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Have a look for Wowemu (there's no official site and I don't want to link to a dodgy site). This is based on ApireCore which is an MMO simulator, or basically a reverse engineer of the WoW protocol. This is what the private WoW servers run off. From what I recall Wowemu is
mySQL
Python
However ApireCore is C++.
The backend for Wowemu is amazingly simple (I tried it in 2005 however) and probably a complete over simplification of the database schema. It does gives you a good idea of what's involved.
Because MMOs by and large require the resources of a business to develop and deploy, at which point they are valuable company IP, there isn't a ton of publicly available information about implementations.
One thing that is fairly certain is that since MMOs by and large use a custom client and 3D renderer they don't use HTTP because they aren't web browsers. Online games are going to have their own protocols built on top of TCP/IP or UDP.
The game simulations themselves will be built using the same techniques as any networked 3D game, so you can look towards resources for that problem domain to learn more.
For the big daddy, World of Warcraft, we can guess that their database is Oracle because Blizzard's job listings frequently cite Oracle experience as a requirement/plus. They use Lua for user interface scripting. C++ and OpenGL (for Mac) and Direct3D (for PC) can be assumed as the implementation languages for the game clients because that's what games are made with.
One company that is cool about discussing their implementation is CCP, creators of Eve online. They have published a number of presentations and articles about Eve's infrastructure, and it is a particularly interesting case because they use Stackless Python for a lot of Eve's implementation.
http://www.disinterest.org/resource/PyCon2006-StacklessInEve.wmv
http://us.pycon.org/2009/conference/schedule/event/91/
There was also a recent Game Developer Magazine article on Eve's architecture:
https://store.cmpgame.com/product/3359/Game-Developer-June%7B47%7DJuly-2009-Issue---Digital-Edition
The Software Engineering radio podcast had an episode with Jim Purbrick about Second Life which discusses servers, worlds, scaling and other MMORPG internals.
Traditionally MMOs have been based on C++ server applications running on Linux communicating with a database for back end storage and fat client applications using OpenGL or DirectX.
In many cases the client and server embed a scripting engine which allows behaviours to be defined in a higher level language. EVE is notable in that it is mostly implemented in Python and runs on top of Stackless rather than being mostly C++ with some high level scripts.
Generally the server sits in a loop reading requests from connected clients, processing them to enforce game mechanics and then sending out updates to the clients. UDP can be used to minimize latency and the retransmission of stale data, but as RPGs generally don't employ twitch gameplay TCP/IP is normally a better choice. Comet or BOSH can be used to allow bi-directional communications over HTTP for web based MMOs and web sockets will soon be a good option there.
If I were building a new MMO today I'd probably use XMPP, BOSH and build the client in JavaScript as that would allow it to work without a fat client download and interoperate with XMPP based IM and voice systems (like gchat). Once WebGL is widely supported this would even allow browser based 3D virtual worlds.
Because the environments are too large to simulate in a single process, they are normally split up geographically between processes each of which simulates a small area of the world. Often there is an optimal population for a world, so multiple copies (shards) are run which different sets of people use.
There's a good presentation about the Second Life architecture by Ian Wilkes who was the Director of Operations here: http://www.infoq.com/presentations/Second-Life-Ian-Wilkes
Most of my talks on Second Life technology are linked to from my blog at: http://jimpurbrick.com
Take a look at Erlang. It's a concurrent programming language and runtime system, and was designed to support distributed, fault-tolerant, soft-real-time, non-stop applications.
I have written a Windows service that allows me to remotely run and stop applications. These applications are run using CreateProcess, and this works for me because most of them only perform backend processing. Recently, I need to run applications that present GUI to the current log in user. How do I code in C++ to allow my service to locate the currently active desktop and run the GUI on it?
Roger Lipscombe's answer, to use WTSEnumerateSessions to find the right desktop, then CreateProcessAsUser to start the application on that desktop (you pass it the handle of the desktop as part of the STARTUPINFO structure) is correct.
However, I would strongly recommend against doing this. In some environments, such as Terminal Server hosts with many active users, determining which desktop is the 'active' one isn't easy, and may not even be possible.
But most importantly, if an application will suddenly appear on a user's desktop, this may very well occur at a bad time (either because the user simply isn't expecting it, or because you're trying to launch the app when the session isn't quite initialized yet, in the process of shutting down, or whatever).
A more conventional approach would be to put a shortcut to a small client app for your service in the global startup group. This app will then launch along with every user session, and can be used start other apps (if so desired) without any juggling of user credentials, sessions and/or desktops.
Also, this shortcut can be moved/disabled by administrators as desired, which will make deployment of your application much easier, since it doesn't deviate from the standards used by other Windows apps...
The short answer is "You don't", as opening a GUI program running under another user context is a security vulnerability commonly known as a Shatter Attack.
Take a look at this MSDN article: Interactive Services. It gives some options for a service to interact with a user.
In short you have these options:
Display a dialog box in the user's session using the WTSSendMessage function.
Create a separate hidden GUI application and use the CreateProcessAsUser function to run the application within the context of the interactive user. Design the GUI application to communicate with the service through some method of interprocess communication (IPC), for example, named pipes. The service communicates with the GUI application to tell it when to display the GUI. The application communicates the results of the user interaction back to the service so that the service can take the appropriate action. Note that IPC can expose your service interfaces over the network unless you use an appropriate access control list (ACL).
If this service runs on a multiuser system, add the application to the following key so that it is run in each session: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run. If the application uses named pipes for IPC, the server can distinguish between multiple user processes by giving each pipe a unique name based on the session ID.
WTSEnumerateSessions and CreateProcessAsUser.
Several people suggested WTSEnumerateSessions and CreateProcessAsUser. I wonder why no one suggested WTSGetActiveConsoleSessionId, since you said you only want to target one logged in user.
Several people sure are right to suggest CreateProcessAsUser though. If you call plain old CreateProcess the way you said, then the application's GUI will run with your service's privileges instead of the user's privileges.
That problems Session 0 , Interactive Services ,
Windows Service Allow Service To Interact With Desktop
on Windows 7 or Windows Vista
You can read this article
http://www.codeproject.com/KB/vista-security/SubvertingVistaUAC.aspx
I try explained here it's working on Windows 7
On Win2K, XP and Win2K3 the console user is logged on in Session 0, the same session the services live in. If a service is configured as interactive, it'll be able to show the UI on the user's desktop.
However, on Vista, no user can be logged on in Session 0. Showing UI from a service there is a bit trickier. You need to enumerate the active sessions using WTSEnumerateSessions API, find the console session and create the process as that user. Of course, you need also a token or user credentials to be able to do that. You can read more details about this process here.
I think as long as you have only one user logged in, it will automatically display on that user's desktop.
Anyway, be very careful when having a service start an exe.
If the write access to the folder with the exe is not restricted, any user can replace that exe with any other program, which will then be run with sytem rights. Take for example cmd.exe (available on all windows sytems). The next time the service tries to start your exe, you get a command shell with system rights...
If you launch a GUI from your service it will show up on the currently active desktop.
But only if you adjusted the service permissions: You need to allow it to interact with the desktop.
Important Services cannot directly interact with a user as of Windows Vista. Therefore, the techniques mentioned in the section titled Using an Interactive Service should not be used in new code.
This is taken from : http://msdn.microsoft.com/en-us/library/ms683502(VS.85).aspx