[bug-inetutils] Re: [PATCH] Make `logger' IPv6-capable.

[Simon Josefsson]

Mats Erik Andersson <address@hidden> writes:

> onsdag den 19 januari 2011 klockan 08:24 skrev Simon Josefsson detta:
>> Mats Erik Andersson <address@hidden> writes:
>> 
>> > Now both are implemented, but '--ipv6' prints a warning message to
>> > STDOUT and falls back to IPv4 if the system is not compiled with IPv6
>> > support.
>
> One correction: The warning goes to STDERR, since it is generated
> by a call
>
>    error(EXIT_SUCCESS, 0, "Warning: Falling back to IPv4, ...").
>
>> Would an error be more appropriate?  I'm thinking scripted use.  OTOH,
>> for logger you would probably prefer to get the log delivered than not
>> to.  Could it log an error message? ;)
>
> I do not understand acronyms like "OTOH", which influences this comment.
> Is my understanding correct in observing these two features?
>
> a) Do you like the call "logger --ipv6 ..." to print the warning to stderr,
>    attempt the requested logging message via IPv4, and also exit execution
>    with a non-zero exit code? Presently the exit code is zero, but the
>    other two parts are included in my suggestion.
>
> b) Do you desire the IPv6 failure to log a local message about the
>    inability to use that transport, thus producing two log messages:
>    the intended text which is possibly non-local and the additional
>    failure report which remains on the local workstation/server?

I haven't made up my mind, but wanted to bring this aspect up for
discussion.

Other InetUtils tools fails when passed a -6 and IPv6 is not working,
for example:

address@hidden:~$ telnet gnu.org
Trying 140.186.70.148...
^C
address@hidden:~$ telnet -6 gnu.org
gnu.org/telnet: lookup failure: No address associated with hostname
address@hidden:~$ 

Generally, it feels more natural for a tool to fail when it cannot do
what it is asked to, rather than give a warning and do something else.

Typically users won't use --ipv4 or --ipv6 but rather use a hostname,
and let the getaddrinfo() do its magic of selecting ipv4 vs ipv6, right?

/Simon