nRF Sniffer Linux Lock File Permissions Problem

RE: nRF Sniffer Linux Lock File Permissions Problem

Positron — Wed, 18 Dec 2024 11:37:46 GMT

Thanks, that's very insightful!

On my Linux Mint I have no problem creating files in /var/lock, but the lockfile never gets removed by sniffer code, so it refuses to start a new capture (unless you restart wireshark). Your suggestion helps!

RE: nRF Sniffer Linux Lock File Permissions Problem

coppice — Tue, 07 Mar 2023 00:02:04 GMT

This thread is old, but I downloaded the sniffer software today, and the problem is still there. The code in Lockfile.py won't work on most modern Linux systems. I am use Fedora 37.

The code tries to use traditional lock files in /var/lock for the serial port, but messes them up. Root status is needed on modern Linux machines to create and write files in /var/lock (or /run/lock, depending on the system). So, they put the lock files for things like serial ports in a subdirectory called /var/lock/lockdev, which anyone can write to. I changed Lockfile.py to use /var/lock/lockdev , but it still gets things wrong. It never removes the locks it has created, even when you run the software as root. For the moment I have disabled the locking and unlocking code, by simply changing the tests in Filelock.py to look for the system be an "xlinux" one, instead of a "linux" one. Now I can capture OK.

RE: nRF Sniffer Linux Lock File Permissions Problem

glassthumb — Thu, 14 Oct 2021 17:35:47 GMT

Thanks for the reply. I just confirmed that the lock file doesn't exist, but it seems to be related to permissions on the /var/lock (symlinked to /run/lock) directory. Changing the permissions on that directory does seem to fix the problem, so appreciate the help!

RE: nRF Sniffer Linux Lock File Permissions Problem

Håkon Alseth — Thu, 14 Oct 2021 07:57:51 GMT

Hi,

[quote user=""](PermissionError: [Errno 13] Permission denied: '/var/lock/LCK..ttyUSB0').[/quote]

I think this is a stale lock file from a previous (root) session. Have you tried deleting it, and see if this then helps the scenario?

Kind regards,

Håkon

RE: nRF Sniffer Linux Lock File Permissions Problem

glassthumb — Wed, 13 Oct 2021 14:55:43 GMT

Initially this was an issue, but I installed nrf-udev which changes the permissions on the serial port when plugged in. Now it seems to be related to the lock file.

RE: nRF Sniffer Linux Lock File Permissions Problem

Håkon Alseth — Wed, 13 Oct 2021 07:40:47 GMT

Hi,

Could this be the reason for the user permission issue?

https://askubuntu.com/questions/133235/how-do-i-allow-non-root-access-to-ttyusb0

Kind regards,

Håkon