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From:   Justin Stitt <justinstitt@google.com>
Date:   Thu, 26 Oct 2023 15:24:54 -0700
Message-ID: <CAFhGd8r-u193pBk2+WWF+sHWEo5ixxEiT=fcSYiuy5W+aWDsbg@mail.gmail.com>
Subject: Re: [PATCH next v2 2/3] checkpatch: add ethtool_sprintf rules
To:     Vladimir Oltean <olteanv@gmail.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
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On Thu, Oct 26, 2023 at 3:12=E2=80=AFPM Vladimir Oltean <olteanv@gmail.com>=
 wrote:
>
> On Thu, Oct 26, 2023 at 09:56:08PM +0000, Justin Stitt wrote:
> > Add some warnings for using ethtool_sprintf() where a simple
> > ethtool_puts() would suffice.
> >
> > The two cases are:
> >
> > 1) Use ethtool_sprintf() with just two arguments:
> > |       ethtool_sprintf(&data, driver[i].name);
> > or
> > 2) Use ethtool_sprintf() with a standalone "%s" fmt string:
> > |       ethtool_sprintf(&data, "%s", driver[i].name);
> >
> > The former may cause -Wformat-security warnings while the latter is jus=
t
> > not preferred. Both are safely in the category of warnings, not errors.
> >
> > Signed-off-by: Justin Stitt <justinstitt@google.com>
> > ---
> >  scripts/checkpatch.pl | 19 +++++++++++++++++++
> >  1 file changed, 19 insertions(+)
> >
> > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> > index 25fdb7fda112..22f007131337 100755
> > --- a/scripts/checkpatch.pl
> > +++ b/scripts/checkpatch.pl
> > @@ -7011,6 +7011,25 @@ sub process {
> >                            "Prefer strscpy, strscpy_pad, or __nonstring=
 over strncpy - see: https://github.com/KSPP/linux/issues/90\n" . $herecurr=
);
> >               }
> >
> > +# ethtool_sprintf uses that should likely be ethtool_puts
> > +             if ($line =3D~ /\bethtool_sprintf\s*\(\s*$FuncArg\s*,\s*$=
FuncArg\s*\)/) {
> > +                     if(WARN("ETHTOOL_SPRINTF",
> > +                        "Prefer ethtool_puts over ethtool_sprintf with=
 only two arguments\n" . $herecurr) &&
> > +         $fix) {
> > +         $fixed[$fixlinenr] =3D~ s/ethtool_sprintf\s*\(/ethtool_puts\(=
/;
> > +       }
> > +             }
> > +
> > +             # use $rawline because $line loses %s via sanitization an=
d thus we can't match against it.
> > +             if ($rawline =3D~ /\bethtool_sprintf\s*\(\s*$FuncArg\s*,\=
s*\"\%s\"\s*,\s*$FuncArg\s*\)/) {
> > +                     if(WARN("ETHTOOL_SPRINTF",
> > +                        "Prefer ethtool_puts over ethtool_sprintf with=
 standalone \"%s\" specifier\n" . $herecurr) &&
> > +         $fix) {
> > +         $fixed[$fixlinenr] =3D~ s/ethtool_sprintf\s*\(\s*(.*?),.*?,(.=
*?)\)/ethtool_puts\($1,$2)/;
> > +       }
> > +             }
> > +
> > +
> >  # typecasts on min/max could be min_t/max_t
> >               if ($perl_version_ok &&
> >                   defined $stat &&
> >
> > --
> > 2.42.0.820.g83a721a137-goog
> >
>
> I don't really know Perl, but does the indentation and coding style here
> conform to any rules, or is it just free-form? The rest of the script
> looks almost as you'd expect from C. This is unreadable to me.

There was some discussion here [1] but AFAICT I need to use EMACS
or configure my vim in a very particular way to get the same formatting

But yeah, look around line 7000 -- lots of this pattern matching code is
pretty hard to read. Not sure there's much to be done as far as readability
is concerned.

[1]: https://lore.kernel.org/all/137a309b313cc8a295f3affc704f0da049f233aa.c=
amel@perches.com/

Thanks
Justin