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From: Lawrence =?iso-8859-13?q?D=FFOliveiro?= <ldo@nz.invalid>
Newsgroups: comp.lang.python
Subject: Re: Python linuxfs Modules
Date: Tue, 17 Mar 2026 21:26:00 -0000 (UTC)
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On Tue, 17 Mar 2026 14:30:42 +0300, Oguz Kaan Ocal wrote:

> Regarding the linuxacl and linuxmount modules: how do you handle
> compatibility across different kernel versions? Since some of these
> APIs (like Landlock or newer mount features) are relatively recent,
> does the library provide graceful fallbacks or just raise
> NotImplementedError?

Landlock in particular has been through about 7 versions so far, with
signs of an eighth on the way. I deal with that by attach API version
info to the relevant enums.

For example, if you look at my Python version of the “sandboxer”
sample program in the Landlock documentation, I get the API version
from the current kernel with

    LL_VERSION = linuxpriv.get_landlock_version()

then I can collect sets of available access attributes with constructs
like:

* All read/write operations on both files and directories:

    access_file_dir_rw = set \
      (
        acc for acc in ACCESS_FS
        if acc.min_version <= LL_VERSION
      )

* Read-only operations on files:

    access_file_ro = set \
      (
        acc for acc in ACCESS_FS
        if acc.min_version <= LL_VERSION and acc.file_op and not acc.write_op
      )

etc.

As for libacl, I’m not aware of any API version changes -- not in the
man pages I’ve been reading so far. Similarly the mount API -- both go
so far back that I don’t think any kernels that don’t implement them
are still in any kind of support. Correct me if I’m wrong. ;)

> Using sets of enums instead of bitmasks is definitely 'The Pythonic
> Way'. It makes the code much more self-documenting.

More than that, I can attach extra attributes that can be used to ease
programming, as in the examples above.