[PATCH next v2 2/3] checkpatch: add ethtool_sprintf rules

[Vladimir Oltean]

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 just
> not preferred. Both are safely in the category of warnings, not errors.
> 
> Signed-off-by: Justin Stitt <justinstitt at 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 =~ /\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] =~ s/ethtool_sprintf\s*\(/ethtool_puts\(/;
> +       }
> +		}
> +
> +		# use $rawline because $line loses %s via sanitization and thus we can't match against it.
> +		if ($rawline =~ /\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] =~ 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.