Search code examples
pythonsubprocesspopensigint

Sending a Ctrl+C SIGINT to sudoed C subprocess from python framework

I'm running a python subprocess using:

p = Popen(["sudo", "./a.out"])

where a.out is a C executable which runs continuously until a SIGINT or Ctrl+C signal is sent to it. I've had trouble with subprocess.Popen object functions such as send_signal() because Operation not permitted errors are raised due to the sudo nature of the executable. After this I tried to send a SIGINT to the subprocess via:

os.system(f"sudo kill -2 {p.pid}")

but this doesn't seem to target the process correctly. Running a quick sudo netstat -lpnt check shows the a.out process is still running on a pid which is different to the one which p.pid returned (usually by a few integers, i.e. p.pid returns 3031 but a.out is 3035). Anything that I've misunderstood?

Solution

  • You are actually getting pid of and killing sudo process (that forked your application process). Instead you should kill the whole process group with:

    import subprocess, os
p = Popen(["sudo", "./a.out"])
pgid = os.getpgid(p.pid)
subprocess.check_output("sudo kill {}".format(pgid))

    or with the help of pkill:

    import subprocess
p = Popen(["sudo", "./a.out"])
subprocess.call(f"sudo pkill -2 -P {p.pid})