Re: [PATCH v2] checkpatch: Detect '%#' or '%0#' in printf-style format strings

[Paolo Bonzini]

On 14/09/20 19:26, Dov Murik wrote:
> According to the coding style document, we should use literal '0x' prefix
> instead of printf's '#' flag (which appears as '%#' or '%0#' in the format
> string).  Add a checkpatch rule to enforce that.
> 
> Note that checkpatch already had a similar rule for trace-events files.
> 
> Example usage:
> 
>   $ scripts/checkpatch.pl --file chardev/baum.c
>   ...
>   ERROR: Don't use '#' flag of printf format ('%#') in format strings, use 
> '0x' prefix instead
>   #366: FILE: chardev/baum.c:366:
>   +            DPRINTF("Broken packet %#2x, tossing\n", req); \
>   ...
>   ERROR: Don't use '#' flag of printf format ('%#') in format strings, use 
> '0x' prefix instead
>   #472: FILE: chardev/baum.c:472:
>   +        DPRINTF("unrecognized request %0#2x\n", req);
>   ...
> 
> Signed-off-by: Dov Murik <dovmurik@linux.vnet.ibm.com>
> ---
> 
> Since v1:
> - consolidate format string checks to avoid code duplication
> 
> ---
>  scripts/checkpatch.pl | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index bd3faa154c..f8dac953b2 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -2880,14 +2880,20 @@ sub process {
>                               $herecurr);
>               }
>  
> -# check for %L{u,d,i} in strings
> +# format strings checks
>               my $string;
>               while ($line =~ /(?:^|")([X\t]*)(?:"|$)/g) {
>                       $string = substr($rawline, $-[1], $+[1] - $-[1]);
>                       $string =~ s/%%/__/g;
> +                     # check for %L{u,d,i} in strings
>                       if ($string =~ /(?<!%)%L[udi]/) {
>                               ERROR("\%Ld/%Lu are not-standard C, use 
> %lld/%llu\n" . $herecurr);
> -                             last;
> +                     }
> +                     # check for %# or %0# in printf-style format strings
> +                     if ($string =~ /(?<!%)%0?#/) {
> +                             ERROR("Don't use '#' flag of printf format " .
> +                                   "('%#') in format strings, use '0x' " .
> +                                   "prefix instead\n" . $herecurr);
>                       }
>               }
>  
> 

Queued, thanks.

Paolo