linux-kernel - Re: [PATCH] checkpatch: Look for symbolic permissions and suggest octal instead

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Date:	Mon, 15 Aug 2016 09:38:34 -0700
From:	Joe Perches <joe@...ches.com>
To:	Andrew Morton <akpm@...ux-foundation.org>,
	Andy Whitcroft <apw@...onical.com>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] checkpatch: Look for symbolic permissions and suggest
 octal instead

On Tue, 2016-08-02 at 16:39 -0700, Joe Perches wrote:
> S_ uses should be avoided where octal is more intelligible.

ping?

Should CodingStyle and Documentation/ﬁlesystems change too?

> Signed-off-by: Joe Perches <joe@...ches.com>
> ---
>  scripts/checkpatch.pl | 49 +++++++++++++++++++++++++++++++++++++++++++------
>  1 file changed, 43 insertions(+), 6 deletions(-)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 1d5b09d..1140940 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -541,6 +541,32 @@ our $mode_perms_world_writable = qr{
>  	0[0-7][0-7][2367]
>  }x;
>  
> +our %mode_permission_string_types = (
> +	"S_IRWXU" => 0700,
> +	"S_IRUSR" => 0400,
> +	"S_IWUSR" => 0200,
> +	"S_IXUSR" => 0100,
> +	"S_IRWXG" => 0070,
> +	"S_IRGRP" => 0040,
> +	"S_IWGRP" => 0020,
> +	"S_IXGRP" => 0010,
> +	"S_IRWXO" => 0007,
> +	"S_IROTH" => 0004,
> +	"S_IWOTH" => 0002,
> +	"S_IXOTH" => 0001,
> +	"S_IRWXUGO" => 0777,
> +	"S_IRUGO" => 0444,
> +	"S_IWUGO" => 0222,
> +	"S_IXUGO" => 0111,
> +);
> +
> +#Create a search pattern for all these strings to speed up a loop below
> +our $mode_perms_string_search = "";
> +foreach my $entry (keys %mode_permission_string_types) {
> +	$mode_perms_string_search .= '|' if ($mode_perms_string_search ne "");
> +	$mode_perms_string_search .= $entry;
> +}
> +
>  our $allowed_asm_includes = qr{(?x:
>  	irq|
>  	memory|
> @@ -5996,20 +6022,31 @@ sub process {
>  					$arg_pos--;
>  					$skip_args = "(?:\\s*$FuncArg\\s*,\\s*){$arg_pos,$arg_pos}";
>  				}
> -				my $test = "\\b$func\\s*\\(${skip_args}([\\d]+)\\s*[,\\)]";
> +				my $test = "\\b$func\\s*\\(${skip_args}($FuncArg(?:\\|\\s*$FuncArg)*)\\s*[,\\)]";
>  				if ($line =~ /$test/) {
>  					my $val = $1;
>  					$val = $6 if ($skip_args ne "");
> -
> -					if ($val !~ /^0$/ &&
> -					    (($val =~ /^$Int$/ && $val !~ /^$Octal$/) ||
> -					     length($val) ne 4)) {
> +					if (($val =~ /^$Int$/ && $val !~ /^$Octal$/) ||
> +					    ($val =~ /^$Octal$/ && length($val) ne 4)) {
>  						ERROR("NON_OCTAL_PERMISSIONS",
>  						      "Use 4 digit octal (0777) not decimal permissions\n" . $herecurr);
> -					} elsif ($val =~ /^$Octal$/ && (oct($val) & 02)) {
> +					}
> +					if ($val =~ /^$Octal$/ && (oct($val) & 02)) {
>  						ERROR("EXPORTED_WORLD_WRITABLE",
>  						      "Exporting writable files is usually an error. Consider more restrictive permissions.\n" . $herecurr);
>  					}
> +					if ($val =~ /\b$mode_perms_string_search\b/) {
> +						my $to = 0;
> +						while ($val =~ /\b($mode_perms_string_search)\b(?:\s*\|\s*)?\s*/g) {
> +							$to |=  $mode_permission_string_types{$1};
> +						}
> +						my $new = sprintf("%04o", $to);
> +						if (WARN("SYMBOLIC_PERMS",
> +							 "Symbolic permissions are not preferred. Consider using octal permissions $new.\n" . $herecurr) &&
> +						    $fix) {
> +							$fixed[$fixlinenr] =~ s/\Q$val\E/$new/;
> +						}
> +					}
>  				}
>  			}
>  		}