How to implement a kill switch in a native windows program

Question

We've got issues with our program potentially hanging in certain situations, is there a way to search and destroy your own program with windows calls without using task manager. It probably wouldn't make sense to include this in the program itself, but as a bundled thing no one would see.

What's the best way to go about doing this, how deep do I need to dig to stop my program and how shallow should I keep to make sure I don't crash the OS?

Answer 1

Although you should probably fix the situation in which it hangs, one way you could have the program kill itself is to spawn a new thread when you launch the app, and have that thread poll the application and kill it if necessary.

Killing a thread in windows.

Answer 2

One option would be to write a Windows Service that serves as a Watchdog. You could find your program by it's .exename and then you need some way to determine if it hangs (for example some simple Inter-Process-Communication or even a Client/Server thing) and restart it if necessary.

That is hardly "no one would see" though.

Answer 3

What about implementing something from the pstools of sysinternals ?

Answer 4

You can terminate a process using TerminateProcess. You'll need to determine the target process id using EnumProcesses and then call OpenProcess to obtain a handle to the process in order to terminate it.

Answer 5

You could create a .bat file and put a Taskkill command in it to forcefully terminate your application. The command would look something like this:

taskkill /f /im notepad.exe

Answer 6

You can enumerate running processes using the EnumProcesses() function. This will let you search for the process name, and get the PID. With the PID, you can open a HANDLE to the process which you need in order to call TerminateProcess() to kill the hung process.

There's an example of how to use EnumProcesses on MSDN.

Some pseudo-code might look something like:

EnumProcesses(pidArray, sizeofArray, &bytesReturned);
for(int i=0; i < bytesReturned/sizeof(DWORD); i++) {
  if(getProcessName(pidArray[i]) == "ourProcess"){
    HANDLE hProc = OpenProcess(PROCESS_TERMINATE, FALSE, pidArray[i]);
    TerminateProcess(hProc, 0);
  }
}