netdev - Re: [PATCH net-next v2 3/8] net: netconsole: move newline trimming to function

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Date: Wed, 31 Jan 2024 20:45:56 -0800
From: Packet Geek <thepacketgeek@...il.com>
To: Breno Leitao <leitao@...ian.org>
Cc: "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, netdev@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next v2 3/8] net: netconsole: move newline trimming to function

On Tue, Jan 30, 2024 at 1:16 AM Breno Leitao <leitao@...ian.org> wrote:
>
> On Fri, Jan 26, 2024 at 03:13:38PM -0800, Matthew Wood wrote:
> > Move newline trimming logic from `dev_name_store()` to a new function
> > (trim_newline()) for shared use in netconsole.c
> >
> > Signed-off-by: Matthew Wood <thepacketgeek@...il.com>
> > ---
> >  drivers/net/netconsole.c | 17 +++++++++++------
> >  1 file changed, 11 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
> > index 085350beca87..b280d06bf152 100644
> > --- a/drivers/net/netconsole.c
> > +++ b/drivers/net/netconsole.c
> > @@ -230,6 +230,16 @@ static struct netconsole_target *to_target(struct config_item *item)
> >                           struct netconsole_target, group);
> >  }
> >
> > +/* Get rid of possible trailing newline, returning the new length */
> > +static void trim_newline(char *s, size_t maxlen)
> > +{
> > +     size_t len;
> > +
> > +     len = strnlen(s, maxlen);
> > +     if (s[len - 1] == '\n')
> > +             s[len - 1] = '\0';
> > +}
>
> I am thinking about this one. Should we replace the first `\n` in the
> file by `\0` no matter where it is? This will probably make it easier to
> implement the netconsd, where we know it will be impossible to have `\n`
> in the userdata.
>
> Maybe something as:
>
>         static inline void trim_newline(char *str)
>         {
>                 char *pos = strchr(str, '\n');
>
>                 if (pos)
>                         *pos = '\0';
>         }
>
>
> All in all, this is a good clean up, which make the code easier to read.
> Thanks!

I like this idea, I agree that only accepting userdata values upto the
first newline clears up the expectations for log output and parsing on
the receiving side. I would prefer that to the case where multiple
values (delimited by newlines) are somehow attempted with a single
key, seems like just using additional key/value pairs would be
cleaner.