How to kill subprocess in gnome terminal

Question

I have three *.py scripts named as:

• terminal_starter,
• subprocess_in_terminal,
• ctrlc_sender

with the following code respectively:

terminal_starter.py

import subprocess
import os

p = subprocess.Popen(['gnome-terminal -e "python subprocess_in_terminal.py"'], shell=True)

gpid = os.getpgrp()
ppid = os.getpid()
p1 = subprocess.Popen(["python ctrlc_sender.py " + str(gpid) + " " + str(ppid)], shell=True)

while 1:
    pass

subprocess_in_terminal.py

import time

while 1:
    print "Subprocess in terminal."
    time.sleep(1)

ctrlc_sender.py

import signal
import os
import sys
import time

gpid = sys.argv[1]
ppid = sys.argv[2]

for i in range(10):
    print "Killer says: I will kill " + gpid + "and " + ppid
    time.sleep(1)

os.killpg(int(gpid), signal.SIGTERM)
os.kill(int(ppid), signal.SIGTERM)

I want to kill subprocess_in_terminal.py but I am not able.

I am running these scripts on Ubuntu 16.04 LTS and Python 2.7.

Any help would be appreciated.

Answer 1

It seems that gnome-terminal detach itself from current parent shell and "adopt" as a parent init process. Thus the parent-ancestor connections between processes is broken and finding the parents and children of our subprocess become a non trivial task.

However if gnome-terminal could be replaced with a "general" shell then I hope that some minimal changes in terminal_starter.py and ctrlc_sender.py could be helpful:

terminal_starter.py

  1 import subprocess
  2 import os
  3 
  4 p = subprocess.Popen(['python subprocess_in_terminal.py'],preexec_fn=os.setsid, shell=True)
  5 
  6 gpid = os.getpgrp()
  7 ppid = os.getpid()
  8 
  9 p1 = subprocess.Popen(["python ctrlc_sender.py " + str(gpid) + " " + str(ppid)], shell=True)
  10 
  11 while 1:
  12         
  13     pass

preexec_fn=os.setsid point our process as a group leader of processes

ctrlc_sender.py

  1 import signal
  2 import os
  3 import sys
  4 import time
  5     
  6 gpid = sys.argv[1]
  7 ppid = sys.argv[2]
  8     
  9 for i in range(10):
 10     print "Killer says: I will kill " + gpid + " and " + ppid
 11     time.sleep(1)
 12 
 13 
 14 import psutil
 15 
 16 paren_proc = psutil.Process(int(ppid))
 17 
 18 for child_proc in parent_proc.children(recursive=True):
 19     child_proc.kill()
 20 parent_proc.kill()

Trough psutil.Process we could recursively kill all children. And after that we could finally kill parent process.