Re: How to troubleshoot extcap applications?

[Roland Knall <rknall () gmail com>]

Could we additionally add a note to README.extcap? Just in case, some
external extcap tools sumble across this as well?

Also, one more thing, have you tested with tshark only or also using qt? Qt
in general redirects all std... pipes, which should not matter as we are
started through dumpcap.

Also, please test on Windows, as it behaves a little different from
Linux/mac in the case of pipes/standard pipes

Change is fine by me

regards
Roland

Am Mi., 1. Dez. 2021 um 14:36 Uhr schrieb Dario Lombardo <lomato () gmail com>:

> I'm ok with this change. I can give you direct support for the extcaps I
> wrote (sshdump/ciscodump, udpdump, randpktdump), and do my best with the
> others.
>
> On Wed, Dec 1, 2021 at 2:18 PM Jirka Novak <j.novak () netsystem cz> wrote:
>
> > Hi,
> >
> >   I noticed issue below and I propose a solution for it. Can I ask for
> > comments?
> >
> >   Every extcap tool has --debug and --debug-file options, but when they
> > are used, it do "nothing". File is created, but it is empty.
> >   Later I found that it must be used with --log-level=debug to really
> > log messages.
> >   The issue is that when you increase --log-level, it logs to console
> > (STDERR). So when extcap is started from Wireshark, it mixes log output
> > with packet data and wireshark gets confused and I found no way how to
> > make it operational.
> >   In other words you can't use debug of extcap from Wireshark.
> >
> >   In code I found that the reason is that wsutils/wscode.c writes every
> > message to STDERR. If application registers additional file, it is
> > copied to it too, but output to STDERR is made in every case.
> >   Applications can replace default writer to STDERR, but no extcap do it.
> >
> >   My proposal is to modify extcap/extcap-base.c:
> > 1) When --debug is used, set log level to debug so you don't have to add
> > --log-level
> > 2) If --log-file used, register custom log writer with
> > ws_log_init_with_writer() which will discard all messages so just write
> > to file will be made.
> > 3) Update log init in every extcap
> >
> >   Change is quite simple, but involves all extcaps. I already tested it
> > and it works. I'm just not sure every extcap.
> >   I'm ready to prepare patch.
> >
> >                                         Best regards,
> >
> >                                                 Jirka
> >
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>
> --
>
> Naima is online.
>
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