[PATCH 04/12] hwsim: Use pgrep instead of ps

[Jouni Malinen]

On Mon, Dec 25, 2023 at 12:21:01PM +0200, Andrei Otcheretianski wrote:
> The ps command as shipped by busybox does not support the "command"
> column. Change the code to use pgrep instead which will work fine in all
> environments.

Something strange happens with this in my test setup..

> diff --git a/tests/hwsim/test_ap_eap.py b/tests/hwsim/test_ap_eap.py
> @@ -7607,20 +7607,15 @@ def test_ap_wpa2_eap_psk_mac_addr_change(dev, apdev):
> -    cmd = subprocess.Popen(['ps', '-eo', 'pid,command'], stdout=subprocess.PIPE)
> -    res = cmd.stdout.read().decode()
> +    cmd = subprocess.Popen(['pgrep', '-nf', 'wpa_supplicant.*' + dev[0].ifname], stdout=subprocess.PIPE)

This call ends up printing "pgrep: uptime" in stderr and there is no
stdout response.

> +    res = cmd.stdout.read().decode().strip()
>      cmd.stdout.close()
>      pid = 0
> -    for p in res.splitlines():
> -        if "wpa_supplicant" not in p:
> -            continue
> -        if dev[0].ifname not in p:
> -            continue
> -        pid = int(p.strip().split(' ')[0])
> -    if pid == 0:
> -        logger.info("Could not find wpa_supplicant PID")
> -    else:
> +    if res:
> +        pid = int(res.strip())

That strip() part here seems unnecessary.

>          logger.info("wpa_supplicant PID %d" % pid)
> +    else:
> +        logger.info("Could not find wpa_supplicant PID")

That else case would leave pid == 0 and that is not going to go well in
the end of this test case with os.kill(pi, signal.SIGSTOP).. I
understand that this is mostly unrelated to the changes here, but since
these change broke determination of the PID, I noticed this as the VM
just getting completely stuck.

-- 
Jouni Malinen                                            PGP id EFC895FA