Re: [PATCH v6] usertools: rewrite pmdinfo

[Bruce Richardson <bruce.richardson@intel.com>]

On Mon, Sep 26, 2022 at 03:44:38PM +0200, Robin Jarry wrote:
> dpdk-pmdinfo.py does not produce any parseable output. The -r/--raw flag
> merely prints multiple independent JSON lines which cannot be fed
> directly to any JSON parser. Moreover, the script complexity is rather
> high for such a simple task: extracting PMD_INFO_STRING from .rodata ELF
> sections. Rewrite it so that it can produce valid JSON.
> 
> Remove the PCI database parsing for PCI-ID to Vendor-Device names
> conversion. This should be done by external scripts (if really needed).
> 
> The script passes flake8, black, isort and pylint checks.
> 
> I have tested this with a matrix of python/pyelftools versions:
> 
>                                  pyelftools
>                0.22  0.23  0.24  0.25  0.26  0.27  0.28  0.29
>         3.6      ok    ok    ok    ok    ok    ok    ok    ok
>         3.7      ok    ok    ok    ok    ok    ok    ok    ok
>  Python 3.8      ok    ok    ok    ok    ok    ok    ok    ok
>         3.9      ok    ok    ok    ok    ok    ok    ok    ok
>         3.10   fail  fail  fail  fail    ok    ok    ok    ok
> 
> All failures with python 3.10 are related to the same issue:
> 
>   File "elftools/construct/lib/container.py", line 5, in <module>
>     from collections import MutableMapping
>   ImportError: cannot import name 'MutableMapping' from 'collections'
> 
> Python 3.10 support is only available since pyelftools 0.26. The script
> will only work with Python 3.6 and later. Update the minimal system
> requirements, docs and release notes.
> 
> Cc: Olivier Matz <olivier.matz@6wind.com>
> Cc: Ferruh Yigit <ferruh.yigit@xilinx.com>
> Cc: Bruce Richardson <bruce.richardson@intel.com>
> Signed-off-by: Robin Jarry <rjarry@redhat.com>
> ---
> v5 -> v6:
> 
> * fixed typo: /etc/ld.so.conf/*.conf -> /etc/ld.so.conf.d/*.conf

I am a little uncertain about doing this parsing, and worried it may be a
bit fragile. The main file for ld.so still is ld.so.conf, which, on my
system anyway, does indeed just have an include for *.conf in the .d
directory. However, is it possible that there are systems out there that
still have entries in ld.so.conf and possibly elsewhere?

I think my preference would still be to shell out to ldconfig and query its
database, or to shell out to ldd to get the dependencies of a .so from
there. I just think it may be more robust, but at the cost of running some
shell commands.

However, I don't feel strongly about this, so if others prefer the
pure-python ld.so.conf parsing approach better, I'm ok with that.

/Bruce