Windows Process Management using Python: Find PIDs and End Processes

Introduction

Interacting with Windows shell to end process is very common, there are many ways to do so, like through the traditional batch script

but to gain more flexibility, using python is probably a better idea.

• os.system is not the most elegant way to use, and it is meant to be replaced by subprocess
• subprocess comes with Python standard library and allows us to spawn new processes, connect to their input/output/error pipes, and obtain their return codes
• psutil (python system and process utilities) is a cross-platform library for retrieving information on running processes and system utilization. However, it is a third-party library

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Bare Minimum

the bare minimum command to kill process utilizes window’s taskkill; which doesn’t matter if we use os.system or subprocess

import os

PROCESS = 'notepad.exe'
STATUS = 'running'  # running or not responding
CMD = r'taskkill /fi "IMAGENAME eq {}" /fi "STATUS eq {}" '.format(PROCESS, STATUS)

os.system(CMD)

Using os.system

Now consider a more flexible case where we want to gather information about the processes like its PID, and then proceed on ending the process. One of the downside of window shell command is that the output can’t be passed on to other command, the output is just text. Therefore, we output the text to a csv file which we will later process.

import csv
import os
import signal
import subprocess

PROCESS = 'notepad.exe'
STATUS = 'running'  # running or not responding
TMP = r'{}/Desktop/tmp.txt'.format(os.environ['userprofile'])
CMD = r'tasklist /fi "IMAGENAME eq {}" /fi "STATUS eq {}" /fo "csv" > "{}"'.format(PROCESS, STATUS, TMP)

# output as csv format
os.system(CMD)

with open(TMP, 'r') as temp:
	reader = csv.reader(temp)
	header = next(reader)
	pids = [int(row[1]) for row in reader]

# kill process
for pid in pids:
	os.kill(pid, signal.SIGTERM) # or signal.SIGKILL 
	print('killed process with pid: {}'.format(pid))

if os.path.exists(TMP):
  os.remove(TMP)

Using subprocess

With subprocess, we no longer need to create a temp file to store the output.

Using psutil

import psutil

PROGRAM = r'maya.exe'

def findProcess(name):    
    procs = list()
    #Iterate over the all the running process
    for proc in psutil.process_iter():
        try:
            if proc.name() == name and proc.status() == psutil.STATUS_RUNNING:
            	pid = proc.pid            	
                procs.append(pid)
        except:
            pass      
    return procs

processes = findProcess(PROGRAM)

we can find process start time by using

import time
startTime = time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(proc.create_time()))

to kill process, either kill() or terminate() will work respectfully, SIGKILL or SIGTERM

p = psutil.Process(PID)
p.terminate()
p.kill()
p.wait

Bonus: Find Open Port (for socket connection)

process = psutil.Process(pid=PID)

connections = process.connections(kind='tcp4')
for c in [x for x in connections if x.status == psutil.CONN_LISTEN]:
    # gets the port number
    print('port opened: {}'.format(c.laddr[-1]))

Bonus: Find Main Window Title

ctypes is a foreign function library for python, resulting a not-pythonic function

Reference

Microsoft Doc - tasklist

ThisPointer - Python : Check if a process is running by name and find it’s Process ID (PID)

Johannes Sasongko - Win32 Python: Getting all window titles

Stack Overflow - Obtain Active window using Python

Microsoft Docs - winuser.h header