[Bug] CAPTURE_BUFFER percentage value causes silent startup hang on macOS

[SamuelXingCheng]

Describe the bug
When setting CAPTURE_BUFFER 10% in maltrail.conf on macOS, the server hangs silently during startup — no error message is shown.

How To Reproduce
Steps to reproduce the behavior:

1. Clone the repository on macOS
2. Set CAPTURE_BUFFER 10% in maltrail.conf
3. Run the server: sudo python3 server.py --debug
4. Server outputs nothing after config load

Expected behavior
The server should either:

• successfully parse the percentage on macOS, or
• fail gracefully with an error message when unable to determine total physical memory.

Screenshots
Not applicable, but terminal log looks like this:
[!] unable to determine total physical memory. Please use absolute value for 'CAPTURE_BUFFER'

Environment

• Device: MacBook Pro (Intel)
• OS: macOS 10.15.7
• Type of Maltrail installation: git clone
• Problematic component: server
• Maltrail version: v0.84
• python-pcapy-ng version: 1.0.9
• Python version: 3.9.13 (inside virtualenv)

Workaround
Setting an absolute value in the config resolves the issue:
CAPTURE_BUFFER 134217728

Additional context
Interestingly, the error message only appears after interrupting the server (e.g. Ctrl+C).
Until then, the program appears to hang silently.

This may mislead users into thinking something else is wrong.

[stamparm]

@SamuelXingCheng please try it now with the latest revision

[MikhailKasimov]

@SamuelXingCheng ping!

[MikhailKasimov]

Hello! @SamuelXingCheng Could you, please, give an explicit feedback on problem status after proposed patches? Problem fixed or still need to be fixed? Thank you!