Re: [Linux-kernel-mentees] [RFC PATCH] checkpatch: add shebang check to EXECUTE_PERMISSIONS

[Lukas Bulwahn <lukas.bulwahn@gmail.com>]

On Mon, 12 Oct 2020, Ujjwal Kumar wrote:

> On 12/10/20 11:47 am, Joe Perches wrote:
> > On Mon, 2020-10-12 at 11:19 +0530, Ujjwal Kumar wrote:
> >> checkpatch.pl checks for invalid EXECUTE_PERMISSIONS on source
> >> files. The script leverages filename extensions and its path in
> >> the repository to decide whether to allow execute permissions on
> >> the file or not.
> >>
> >> Based on current check conditions, a perl script file having
> >> execute permissions, without '.pl' extension in its filename
> >> and not belonging to 'scripts/' directory is reported as ERROR
> >> which is a false-positive.
> >>
> >> Adding a shebang check along with current conditions will make
> >> the check more generalised and improve checkpatch reports.
> >> To do so, without breaking the core design decision of checkpatch,
> >> we can fetch the first line from the patch itself and match it for
> >> a shebang pattern.
> >>
> >> There can be cases where the first line is not part of the patch.
> > 
> > For instance: a patch that only changes permissions
> > without changing any of the file content.
> > 
> >>
> >> In that case there may be a false-positive report but in the end we
> >> will have less false-positives as we will be handling some of the
> >> unhandled cases.
> > 
> >> Signed-off-by: Ujjwal Kumar <ujjwalkumar0501@gmail.com>
> >> ---
> >> Apologies, I forgot to include linux-kernel@vger.kernel.org so I'm
> >> now resending.
> >>
> >>  scripts/checkpatch.pl | 19 +++++++++++++++++++
> >>  1 file changed, 19 insertions(+)
> >>
> >> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> > []
> >> @@ -1795,6 +1795,23 @@ sub get_stat_here {
> >>  	return $herectx;
> >>  }
> > 
> > First some style trivia:
> > 
> >> +sub get_shebang {
> >> +	my ($linenr, $realfile) = @_;
> >> +	my $rawline = "";
> >> +	my $shebang = "";
> >> +
> >> +	$rawline = raw_line($linenr, 3);
> >> +	if (defined $rawline &&
> >> +		$rawline =~ /^\@\@ -\d+(?:,\d+)? \+(\d+)(,(\d+))? \@\@/) {
> > 
> > alignment to open parenthesis please
> > 
> >> +		if (defined $1 && $1 == 1) {
> >> +			$shebang = raw_line($linenr, 4);
> >> +			$shebang = substr $shebang, 1;
> > 
> > parentheses around substr please.
> > 
> >> +		}
> >> +	}
> >> +
> >> +	return $shebang;
> >> +}
> > 
> > And some real notes:
> > 
> > $realfile isn't used in this function so there doesn't
> > seem to be a reason to have it as an function argument.
> > 
> >> +
> >>  sub cat_vet {
> >>  	my ($vet) = @_;
> >>  	my ($res, $coded);
> >> @@ -2680,7 +2697,9 @@ sub process {
> >>  # Check for incorrect file permissions
> >>  		if ($line =~ /^new (file )?mode.*[7531]\d{0,2}$/) {
> > 
> > probably better here to use a capture group for the permissions
> > 
> > 		if ($line =~ /^new (?:file )?mode (\d+)$/) {
> > 			my $mode = substr($1, -3);
> 
> This
> 
> > 
> >>  			my $permhere = $here . "FILE: $realfile\n";
> >> +			my $shebang = get_shebang($linenr, $realfile);
> >>  			if ($realfile !~ m@scripts/@ &&
> > 
> > Maybe remove the $realfile directory test as
> > there are many source files that are not scripts
> > in this directory and its subdirectories.
> 
> this
> 
> > 
> >> +			    $shebang !~ /^#!\s*(\/\w)+.*/ &&
> > 
> > unnecessary capture group
> > 
> > and add
> > 
> > 			   $mode =~ /[1357]/ &&
> 
> this
> 
> > 
> >>  			    $realfile !~ /\.(py|pl|awk|sh)$/) {
> > 
> > No need for a a capture group here either. (existing defect)
> 
> and this.
> 
> > 
> >>  				ERROR("EXECUTE_PERMISSIONS",
> >>  				      "do not set execute permissions for source files\n" . $permhere);
> > 
> > 
> > 
> 
> Should these new changes go as a separate patch or can they be
> included in the next iteration of this patch?
> 
>

Ujjwal, please consider the following 'strategy':

- Send one patch to clean up the existing implementation as Joe requested.

With those 'credit points' for cleaning up the implementation, you then:

- Send another clean patch for the additional functionality you propose

We can probably easily accept the first cleanup, and then dig into the 
review of the additional functionality.

Lukas
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