Python: kill subprocess does not work (wrong PID)

Question

I am trying to start a .exe from a Python program, let it run for a couple of seconds and then kill it. I'm using the subprocess library. Here's what I did (in short):

import subprocess

p = subprocess.Popen('start /b .\ssf.exe', shell=True)
time.sleep(5)
p.terminate()

I also tried p.kill(), but without any luck.

Also, when I print(p.pid), it's a different PID than the one I find in the processes list... Can someone tell me why this is not working?

score 4 · Answer 1 · answered Jul 05 '18 at 16:28

4

You didn't start ssf.exe in a subprocess. You started a subprocess that would start ssf.exe in yet another process. When you run p.terminate(), you're terminating the middleman, not ssf.exe.

answered Jul 05 '18 at 16:28

user2357112

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arunp9294 · Answer 2 · 2018-07-05T16:00:25.080

1

Try this:

import os
import signal
import subprocess

p = subprocess.Popen('start /b .\ssf.exe', shell=True, preexec_fn=os.setsid)
time.sleep(5)
os.killpg(os.getpgid(p.pid), signal.SIGTERM)

edited Jul 05 '18 at 16:00

answered Jul 05 '18 at 15:53

arunp9294

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I found that solution here on Stackoverflow as well but it does not work for me: `AttributeError: module 'os' has no attribute 'killpg'` – vdvaxel Jul 05 '18 at 15:55
https://stackoverflow.com/questions/4789837/how-to-terminate-a-python-subprocess-launched-with-shell-true – arunp9294 Jul 05 '18 at 15:57
I tried adding "exec" in front of my command but that doesn't start the exe at all: `exec start /b .\ssf.exe` – vdvaxel Jul 05 '18 at 16:00
How do you run it in the shell? python verision ? windows or linux? – arunp9294 Jul 05 '18 at 16:01
When I open command prompt in the same folder as the ssf.exe, I just type .\ssf.exe and it runs the program. The reason I added `start /b` is because I didn't want it to open a new command prompt. – vdvaxel Jul 05 '18 at 16:02
Remove start /b and try, and add preexec_fn=os.setsid to subprocess options – arunp9294 Jul 05 '18 at 16:05
Error: `AttributeError: module 'os' has no attribute 'setsid'` – vdvaxel Jul 05 '18 at 16:06
my bad. on windows os functionalities are not availble, https://stackoverflow.com/questions/47016723/windows-equivalent-for-spawning-and-killing-separate-process-group-in-python-3 – arunp9294 Jul 05 '18 at 16:08
So what should I try now? – vdvaxel Jul 05 '18 at 16:09
Your python version? – arunp9294 Jul 05 '18 at 16:10
Python version 3.6 – vdvaxel Jul 05 '18 at 16:10
I tried the solution in the link you sent but I get this error: `SystemError: returned a result with an error set` – vdvaxel Jul 05 '18 at 16:12
Is it possible to just kill a process based on its name? The process is called ssf.exe and there's no other process called like that. – vdvaxel Jul 05 '18 at 16:16
1

Found it: `os.system("taskkill /f /im ssf.exe")` – vdvaxel Jul 05 '18 at 16:23
import psutil PROCNAME = "ssf.exe" for proc in psutil.process_iter(): # check whether the process name matches if proc.name() == PROCNAME: proc.kill() – arunp9294 Jul 05 '18 at 16:24

score 1 · Answer 3 · answered Jul 05 '18 at 16:24

1

I figured that killing the process was the easiest:

os.system("taskkill /f /im ssf.exe")

answered Jul 05 '18 at 16:24

vdvaxel

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Python: kill subprocess does not work (wrong PID)

3 Answers3