Is it possible to send ctrl-C (SIGINT) to an application on Windows?

Question

I have (in the past) written cross-platform (Windows / Unix) applications that, when launched from the command line, processed the user-typed combination Ctrl - C in the same way (that is, the application is clean to complete).

Is it possible that Windows will send the Ctrl - C / SIGINT / equivalent to the process from another (unrelated) process to request its termination (giving it the ability to remove resources, etc.)?

Answer 1

The closest I came to a solution is a third-party SendSignal application. The author lists the source code and executable file. I checked that it works under 64-bit windows (it works like a 32-bit program, killing another 32-bit program), but I did not understand how to embed code in a Windows program (either 32-bit or 64-bit).

How it works:

After searching the debugger many times, I found that the entry point, which actually performs the behavior associated with a ctrl-break signal, is kernel32! CtrlRoutine The function had the same prototype as ThreadProc, so it can be used directly with CreateRemoteThread, without the need to enter code. However, this is not an exported character! It is on different addresses (and even has different names) on different versions of Windows. What to do?

Here is the solution I finally came up with. I install the ctrl console handler for my application and then generate the ctrl-break signal for my application. When my handler is called, I look at the top of the stack to find out the parameters passed to kernel32! BaseThreadStart. I take the first parameter, which is the desired starting address of the thread, which is the kernel32 address! CtrlRoutine Then I return from my handler, indicating that I have processed the signal, and my application should not be terminated. Returning to the main thread, I wait until the kernel address is found32! CtrlRoutine Once I succeed, I create a remote thread in the target process with an open start address. This causes the ctrl handlers in the target process to evaluate as if ctrl-break were pressed!

It is nice that only the target process is affected, and any process (even the window process) can be targeted. One drawback is that my small application cannot be used in a batch file, since it will kill it when it fires a ctrl-break event to detect the kernel32 address! CtrlRoutine

(Assume it with start if it is running in a batch file.)

Answer 2

I did some research on this topic, which turned out to be more popular than I expected. KindDragon's answer was one of the key points.

I wrote a longer blog post on this topic and created a working demo program that demonstrates using this type of system to close a command-line application in a couple of nice mods. This post also lists the external links that I used in my research.

In short, these demos do the following:

• Run the program with a visible window using .Net, hide with pinvoke, start for 6 seconds, show with pinvoke, stop with .Net.
• Run the program without a window using .Net, start for 6 seconds, stop by connecting the console and running ConsoleCtrlEvent

Edit: A fixed solution from KindDragon for those interested in the code here and now. If you plan to start other programs after stopping the first one, you need to enable Ctrl-C processing again, otherwise the next process will inherit the parent disabled state and will not respond to Ctrl-C.

 [DllImport("kernel32.dll", SetLastError = true)] static extern bool AttachConsole(uint dwProcessId); [DllImport("kernel32.dll", SetLastError = true, ExactSpelling = true)] static extern bool FreeConsole(); [DllImport("kernel32.dll")] static extern bool SetConsoleCtrlHandler(ConsoleCtrlDelegate HandlerRoutine, bool Add); delegate bool ConsoleCtrlDelegate(CtrlTypes CtrlType); // Enumerated type for the control messages sent to the handler routine enum CtrlTypes : uint { CTRL_C_EVENT = 0, CTRL_BREAK_EVENT, CTRL_CLOSE_EVENT, CTRL_LOGOFF_EVENT = 5, CTRL_SHUTDOWN_EVENT } [DllImport("kernel32.dll")] [return: MarshalAs(UnmanagedType.Bool)] private static extern bool GenerateConsoleCtrlEvent(CtrlTypes dwCtrlEvent, uint dwProcessGroupId); public void StopProgram(Process proc) { //This does not require the console window to be visible. if (AttachConsole((uint)proc.Id)) { // Disable Ctrl-C handling for our program SetConsoleCtrlHandler(null, true); GenerateConsoleCtrlEvent(CtrlTypes.CTRL_C_EVENT, 0); //Moved this command up on suggestion from Timothy Jannace (see comments below) FreeConsole(); // Must wait here. If we don't and re-enable Ctrl-C // handling below too fast, we might terminate ourselves. proc.WaitForExit(2000); //Re-enable Ctrl-C handling or any subsequently started //programs will inherit the disabled state. SetConsoleCtrlHandler(null, false); } } 

Also, plan your solution in case of unforeseen circumstances if AttachConsole() or the sent signal will not work, for example, sleep mode, and then:

 if (!proc.HasExited) { try { proc.Kill(); } catch (InvalidOperationException e){} } 

Answer 3

I think I'm a little late for this question, but I will write something anyway for those who have the same problem. This is the same answer as I gave this question.

My problem was that I would like my application to be a graphical application, but running processes should run in the background without connecting an interactive console window. I think this solution should also work when the parent process is a console process. You may need to remove the CREATE_NO_WINDOW flag.

I was able to solve this problem using GenerateConsoleCtrlEvent () using a wrapper application. The difficult part is that the documentation is not entirely clear how it can be used, and the pitfalls with it.

My decision is based on what is described here . But in fact, this did not explain all the details with an error, so here is the detailed information on how to make it work.

Create a new helper application, Helper.exe. This application will be between your application (parent) and the child process that you want to close. He will also create the actual child process. You must have this process "average person", otherwise GenerateConsoleCtrlEvent () will fail.

Use some kind of IPC mechanism to communicate from the parent to the helper process, which the helper must close the child process. When the helper receives this event, it calls "GenerateConsoleCtrlEvent (CTRL_BREAK, 0)", which closes itself and the child process. I used the event object for this myself, which the parent terminates when he wants to cancel the child process.

To create your Helper.exe, create it using CREATE_NO_WINDOW and CREATE_NEW_PROCESS_GROUP. And when creating a child process, create it without the flags (0), i.e. it will output the console from its parent. Otherwise, it will ignore the event.

It is very important that each step is performed as follows. I tried all kinds of combinations, but this combination is the only one that works. You cannot send event CTRL_C. This will return success, but the process will be ignored. CTRL_BREAK is the only one that works. It doesn't matter much, because in the end they will call ExitProcess ().

You also cannot call GenerateConsoleCtrlEvent () with the process groupd identifier of the child process identifier, which directly allows the auxiliary process to continue to live. It will also fail.

I spent the whole day trying to get this to work. This solution works for me, but if anyone has something else, please add. I went on the net, finding many people with similar problems, but without a specific solution to the problem. How GenerateConsoleCtrlEvent () works, it's also a bit weird, so if anyone knows more details about this, share it.

Answer 4

Edit:

For a GUI application, the “normal” way to handle this when developing Windows is to send a WM_CLOSE message to the main process window.

For a console application, you need to use SetConsoleCtrlHandler to add CTRL_C_EVENT .

If the application does not comply with this, you can call TerminateProcess .

Answer 5

Somehow, GenerateConsoleCtrlEvent() return an error if you call it for another process, but you can connect to another console application and send an event to all child processes.

 void SendControlC(int pid) { AttachConsole(pid); // attach to process console SetConsoleCtrlHandler(NULL, TRUE); // disable Control+C handling for our app GenerateConsoleCtrlEvent(CTRL_C_EVENT, 0); // generate Control+C event } 

Answer 6

Here is the code that I use in my C ++ application.

Positive points:

• Works with console application
• Works from windows service
• No delay required
• Does not close the current application

Negative points:

• The main console is lost and a new one is created (see FreeConsole )
• Switching the console gives strange results ...

---

 // Inspired from http://stackoverflow.com/a/15281070/1529139 // and http://stackoverflow.com/q/40059902/1529139 bool signalCtrl(DWORD dwProcessId, DWORD dwCtrlEvent) { bool success = false; DWORD thisConsoleId = GetCurrentProcessId(); // Leave current console if it exists // (otherwise AttachConsole will return ERROR_ACCESS_DENIED) bool consoleDetached = (FreeConsole() != FALSE); if (AttachConsole(dwProcessId) != FALSE) { // Add a fake Ctrl-C handler for avoid instant kill is this console // WARNING: do not revert it or current program will be also killed SetConsoleCtrlHandler(nullptr, true); success = (GenerateConsoleCtrlEvent(dwCtrlEvent, 0) != FALSE); FreeConsole(); } if (consoleDetached) { // Create a new console if previous was deleted by OS if (AttachConsole(thisConsoleId) == FALSE) { int errorCode = GetLastError(); if (errorCode == 31) // 31=ERROR_GEN_FAILURE { AllocConsole(); } } } return success; } 

Usage example:

 DWORD dwProcessId = ...; if (signalCtrl(dwProcessId, CTRL_C_EVENT)) { cout << "Signal sent" << endl; } 

Answer 7

  void SendSIGINT( HANDLE hProcess ) { DWORD pid = GetProcessId(hProcess); FreeConsole(); if (AttachConsole(pid)) { // Disable Ctrl-C handling for our program SetConsoleCtrlHandler(NULL, true); GenerateConsoleCtrlEvent(CTRL_C_EVENT, 0); // SIGINT //Re-enable Ctrl-C handling or any subsequently started //programs will inherit the disabled state. SetConsoleCtrlHandler(NULL, false); WaitForSingleObject(hProcess, 10000); } } 

Answer 8

This should be clear, because at the moment it is not. There is a modified and compiled version of SendSignal for sending Ctrl-C (by default, it sends only Ctrl + Break). Here are some binary files:

(2014-3-7): I built a 32-bit and 64-bit version with Ctrl-C, it is called SendSignalCtrlC.exe, and you can download it at: https://dl.dropboxusercontent.com/u/49065779 /sendsignalctrlc/x86/SendSignalCtrlC.exe https://dl.dropboxusercontent.com/u/49065779/sendsignalctrlc/x86_64/SendSignalCtrlC.exe - Yuray Mikhalak

I also flipped these files just in case:
32-bit version: https://www.dropbox.com/s/r96jxglhkm4sjz2/SendSignalCtrlC.exe?dl=0
64-bit version: https://www.dropbox.com/s/hhe0io7mcgcle1c/SendSignalCtrlC64.exe?dl=0

Disclaimer: I did not create these files. No changes to the source files. The only platform tested is 64-bit Windows 7. It is recommended that you adapt the source code available at http://www.latenighthacking.com/projects/2003/sendSignal/ and compile it yourself.

Answer 9

In Java, using JNA with the Kernel32.dll library is similar to a C ++ solution. Starts the main CtrlCSender method as a process, which simply receives the console of the process to dispatch the Ctrl + C event and generates an event. Since it runs separately without a console, the Ctrl + C event does not need to be turned off and on again.

CtrlCSender.java - based on Nemo1024 and KindDragon .

Given a well-known process identifier, this console application will attach the console of the target process and generate the CTRL + C event on it.

 import com.sun.jna.platform.win32.Kernel32; public class CtrlCSender { public static void main(String args[]) { int processId = Integer.parseInt(args[0]); Kernel32.INSTANCE.AttachConsole(processId); Kernel32.INSTANCE.GenerateConsoleCtrlEvent(Kernel32.CTRL_C_EVENT, 0); } } 

Main application - launches CtrlCSender as a separate consolation process

 ProcessBuilder pb = new ProcessBuilder(); pb.command("javaw", "-cp", System.getProperty("java.class.path", "."), CtrlCSender.class.getName(), processId); pb.redirectErrorStream(); pb.redirectOutput(ProcessBuilder.Redirect.INHERIT); pb.redirectError(ProcessBuilder.Redirect.INHERIT); Process ctrlCProcess = pb.start(); ctrlCProcess.waitFor(); 

Answer 10

Based on the process identifier, we can send a signal for processing to terminate forcibly or gracefully or any other signal.

List of all processes:

 C:\>tasklist 

To kill the process:

 C:\>Taskkill /IM firefox.exe /F or C:\>Taskkill /PID 26356 /F 

More details:

http://tweaks.com/windows/39559/kill-processes-from-command-prompt/

Answer 11

I found all this too complicated and used SendKeys to send the CTRL - C keypress to the command line window (e.g. cmd.exe window) as a workaround.

Answer 12

My friend suggested a completely different way to solve the problem, and it worked for me. Use vbscript as shown below. It starts and starts, starts within 7 seconds and closes it with ctrl + c .

'VBScript example

 Set WshShell = WScript.CreateObject("WScript.Shell") WshShell.Run "notepad.exe" WshShell.AppActivate "notepad" WScript.Sleep 7000 WshShell.SendKeys "^C"