scripts/checkpatch.pl

#!/usr/bin/perl -w
# (c) 2001, Dave Jones. <davej@codemonkey.org.uk> (the file handling bit)
# (c) 2005, Joel Scohpp <jschopp@austin.ibm.com> (the ugly bit)
# (c) 2007, Andy Whitcroft <apw@uk.ibm.com> (new conditions, test suite, etc)
# Licensed under the terms of the GNU GPL License version 2

use strict;

my $P = $0;

my $V = '0.01';

use Getopt::Long qw(:config no_auto_abbrev);

my $quiet = 0;
my $tree = 1;
my $chk_signoff = 1;
my $chk_patch = 1;
GetOptions(
	'q|quiet'	=> \$quiet,
	'tree!'		=> \$tree,
	'signoff!'	=> \$chk_signoff,
	'patch!'	=> \$chk_patch,
) or exit;

my $exit = 0;

if ($#ARGV < 0) {
	print "usage: patchstylecheckemail.pl [options] patchfile\n";
	print "version: $V\n";
	print "options: -q           => quiet\n";
	print "         --no-tree    => run without a kernel tree\n";
	exit(1);
}

if ($tree && !top_of_kernel_tree()) {
	print "Must be run from the top-level dir. of a kernel tree\n";
	exit(2);
}

my @deprecated = ();
my $removal = 'Documentation/feature-removal-schedule.txt';
if ($tree && -f $removal) {
	open(REMOVE, "<$removal") || die "$P: $removal: open failed - $!\n";
	while (<REMOVE>) {
		if (/^Files:\s+(.*\S)/) {
			for my $file (split(/[, ]+/, $1)) {
				if ($file =~ m@include/(.*)@) {
					push(@deprecated, $1);
				}
			}
		}
	}
}

my @lines = ();
while (<>) {
	chomp;
	push(@lines, $_);
	if (eof(ARGV)) {
		if (!process($ARGV, @lines)) {
			$exit = 1;
		}
		@lines = ();
	}
}

exit($exit);

sub top_of_kernel_tree {
	if ((-f "COPYING") && (-f "CREDITS") && (-f "Kbuild") &&
	    (-f "MAINTAINERS") && (-f "Makefile") && (-f "README") &&
	    (-d "Documentation") && (-d "arch") && (-d "include") &&
	    (-d "drivers") && (-d "fs") && (-d "init") && (-d "ipc") &&
	    (-d "kernel") && (-d "lib") && (-d "scripts")) {
		return 1;
	}
	return 0;
}

sub expand_tabs {
	my ($str) = @_;

	my $res = '';
	my $n = 0;
	for my $c (split(//, $str)) {
		if ($c eq "\t") {
			$res .= ' ';
			$n++;
			for (; ($n % 8) != 0; $n++) {
				$res .= ' ';
			}
			next;
		}
		$res .= $c;
		$n++;
	}

	return $res;
}

sub cat_vet {
	my ($vet) = @_;

	$vet =~ s/\t/^I/;
	$vet =~ s/$/\$/;

	return $vet;
}

sub process {
	my $filename = shift;
	my @lines = @_;

	my $linenr=0;
	my $prevline="";
	my $stashline="";

	my $lineforcounting='';
	my $indent;
	my $previndent=0;
	my $stashindent=0;

	my $clean = 1;
	my $signoff = 0;
	my $is_patch = 0;

	# Trace the real file/line as we go.
	my $realfile = '';
	my $realline = 0;
	my $realcnt = 0;
	my $here = '';
	my $in_comment = 0;
	my $first_line = 0;

	foreach my $line (@lines) {
		$linenr++;

#extract the filename as it passes
		if ($line=~/^\+\+\+\s+(\S+)/) {
			$realfile=$1;
			$in_comment = 0;
			next;
		}
#extract the line range in the file after the patch is applied
		if ($line=~/^\@\@ -\d+,\d+ \+(\d+)(,(\d+))? \@\@/) {
			$is_patch = 1;
			$first_line = 1;
			$in_comment = 0;
			$realline=$1-1;
			if (defined $2) {
				$realcnt=$3+1;
			} else {
				$realcnt=1+1;
			}
			next;
		}

#track the line number as we move through the hunk
		if ($line=~/^[ \+]/) {
			$realline++;
			$realcnt-- if ($realcnt != 0);

			# track any sort of multi-line comment.  Obviously if
			# the added text or context do not include the whole
			# comment we will not see it. Such is life.
			#
			# Guestimate if this is a continuing comment.  If this
			# is the start of a diff block and this line starts
			# ' *' then it is very likely a comment.
			if ($first_line and $line =~ m@^.\s*\*@) {
				$in_comment = 1;
			}
			if ($line =~ m@/\*@) {
				$in_comment = 1;
			}
			if ($line =~ m@\*/@) {
				$in_comment = 0;
			}

			$lineforcounting = $line;
			$lineforcounting =~ s/^\+//;
			$lineforcounting = expand_tabs($lineforcounting);

			my ($white) = ($lineforcounting =~ /^(\s*)/);
			$indent = length($white);

			# Track the previous line.
			($prevline, $stashline) = ($stashline, $line);
			($previndent, $stashindent) = ($stashindent, $indent);
			$first_line = 0;
		}

#make up the handle for any error we report on this line
		$here = "PATCH: $ARGV:$linenr:";
		$here .= "\nFILE: $realfile:$realline:" if ($realcnt != 0);

		my $herecurr = "$here\n$line\n\n";
		my $hereprev = "$here\n$prevline\n$line\n\n";

#check the patch for a signoff:
		if ($line =~ /^\s*Signed-off-by:\s/) {
			$signoff++;

		} elsif ($line =~ /^\s*signed-off-by:/i) {
			if (!($line =~ /^\s*Signed-off-by:/)) {
				print "use Signed-off-by:\n";
				print "$herecurr";
				$clean = 0;
			}
			if ($line =~ /^\s*signed-off-by:\S/i) {
				print "need space after Signed-off-by:\n";
				print "$herecurr";
				$clean = 0;
			}
		}

#ignore lines not being added
		if ($line=~/^[^\+]/) {next;}

# check we are in a valid source file *.[hcsS] if not then ignore this hunk
		next if ($realfile !~ /\.[hcsS]$/);

#trailing whitespace
		if ($line=~/\S\s+$/) {
			my $herevet = "$here\n" . cat_vet($line) . "\n\n";
			print "trailing whitespace\n";
			print "$herevet";
			$clean = 0;
		}
#80 column limit
		if (!($prevline=~/\/\*\*/) && length($lineforcounting) > 80) {
			print "line over 80 characters\n";
			print "$herecurr";
			$clean = 0;
		}

# check we are in a valid source file *.[hc] if not then ignore this hunk
		next if ($realfile !~ /\.[hc]$/);

# at the beginning of a line any tabs must come first and anything
# more than 8 must use tabs.
		if ($line=~/^\+\s* \t\s*\S/ or $line=~/^\+\s*        \s*/) {
			my $herevet = "$here\n" . cat_vet($line) . "\n\n";
			print "use tabs not spaces\n";
			print "$herevet";
			$clean = 0;
		}

		#
		# The rest of our checks refer specifically to C style
		# only apply those _outside_ comments.
		#
		next if ($in_comment);

# no C99 // comments
		if ($line =~ m@//@ and !($line =~ m@\".*//.*\"@)) {
			print "do not use C99 // comments\n";
			print "$herecurr";
			$clean = 0;
		}

		# Remove comments from the line before processing.
		$line =~ s@/\*.*\*/@@g;
		$line =~ s@/\*.*@@;
		$line =~ s@.*\*/@@;
		$line =~ s@//.*@@;

#EXPORT_SYMBOL should immediately follow its function closing }.
		if (($line =~ /EXPORT_SYMBOL.*\(.*\)/) ||
		    ($line =~ /EXPORT_UNUSED_SYMBOL.*\(.*\)/)) {
			if (($prevline !~ /^}/) &&
			   ($prevline !~ /^\+}/) &&
			   ($prevline !~ /^ }/)) {
				print "EXPORT_SYMBOL(func); should immediately follow its function\n";
				print "$herecurr";
				$clean = 0;
			}
		}

		# check for static initialisers.
		if ($line=~/\s*static\s.*=\s+(0|NULL);/) {
			print "do not initialise statics to 0 or NULL\n";
			print "$herecurr";
			$clean = 0;
		}

		# check for new typedefs.
		if ($line=~/\s*typedef\s/) {
			print "do not add new typedefs\n";
			print "$herecurr";
			$clean = 0;
		}

# * goes on variable not on type
		if ($line=~/[A-Za-z\d_]+\* [A-Za-z\d_]+/) {
			print "\"foo* bar\" should be \"foo *bar\"\n";
			print "$herecurr";
			$clean = 0;
		}

# # no BUG() or BUG_ON()
# 		if ($line =~ /\b(BUG|BUG_ON)\b/) {
# 			print "Try to use WARN_ON & Recovery code rather than BUG() or BUG_ON()\n";
# 			print "$herecurr";
# 			$clean = 0;
# 		}

# printk should use KERN_* levels
		if ($line =~ /\bprintk\((?!KERN_)/) {
			print "printk() should include KERN_ facility level\n";
			print "$herecurr";
			$clean = 0;
		}

#function brace can't be on same line, except for #defines of do while, or if closed on same line
		if (($line=~/[A-Za-z\d_]+\**\s+\**[A-Za-z\d_]+\(.*\).* {/) and
		    !($line=~/\#define.*do\s{/) and !($line=~/}/)) {
			print "braces following function declarations go on the next line\n";
			print "$herecurr";
			$clean = 0;
		}
		my $opline = $line;
		$opline =~ s/^.//;
		if (!($line=~/\#\s*include/)) {
			# Check operator spacing.
			my @elements = split(/(<<=|>>=|<=|>=|==|!=|\+=|-=|\*=|\/=|%=|\^=|\|=|&=|->|<<|>>|<|>|=|!|~|&&|\|\||,|\^|\+\+|--|;|&|\||\+|-|\*|\/\/|\/)/, $opline);
			for (my $n = 0; $n < $#elements; $n += 2) {
				# $wN says we have white-space before or after
				# $sN says we have a separator before or after
				# $oN says we have another operator before or after
				my $w1 = $elements[$n] =~ /\s$/;
				my $s1 = $elements[$n] =~ /(\[|\(|\s)$/;
				my $o1 = $elements[$n] eq '';
				my $op = $elements[$n + 1];
				my $w2 = 1;
				my $s2 = 1;
				my $o2 = 0;
				# If we have something after the operator handle it.
				if (defined $elements[$n + 2]) {
					$w2 = $elements[$n + 2] =~ /^\s/;
					$s2 = $elements[$n + 2] =~ /^(\s|\)|\]|;)/;
					$o2 = $elements[$n + 2] eq '';
				}

				# Generate the context.
				my $at = "here: ";
				for (my $m = $n; $m >= 0; $m--) {
					if ($elements[$m] ne '') {
						$at .= $elements[$m];
						last;
					}
				}
				$at .= $op;
				for (my $m = $n + 2; defined $elements[$m]; $m++) {
					if ($elements[$m] ne '') {
						$at .= $elements[$m];
						last;
					}
				}

				##print "<$s1:$op:$s2> <$elements[$n]:$elements[$n + 1]:$elements[$n + 2]>\n";
				# Skip things apparently in quotes.
				next if ($line=~/\".*\Q$op\E.*\"/ or $line=~/\'\Q$op\E\'/);

				# We need ; as an operator.  // is a comment.
				if ($op eq ';' or $op eq '//') {

				# -> should have no spaces
				} elsif ($op eq '->') {
					if ($s1 or $s2) {
						print "no spaces around that '$op' $at\n";
						print "$herecurr";
						$clean = 0;
					}

				# , must have a space on the right.
				} elsif ($op eq ',') {
					if (!$s2) {
						print "need space after that '$op' $at\n";
						print "$herecurr";
						$clean = 0;
					}

				# unary ! and unary ~ are allowed no space on the right
				} elsif ($op eq '!' or $op eq '~') {
					if (!$s1 && !$o1) {
						print "need space before that '$op' $at\n";
						print "$herecurr";
						$clean = 0;
					}
					if ($s2) {
						print "no space after that '$op' $at\n";
						print "$herecurr";
						$clean = 0;
					}

				# unary ++ and unary -- are allowed no space on one side.
				} elsif ($op eq '++' or $op eq '--') {
					if (($s1 && $s2) || ((!$s1 && !$o1) && (!$s2 && !$o2))) {
						print "need space one side of that '$op' $at\n";
						print "$herecurr";
						$clean = 0;
					}

				# & is both unary and binary
				# unary:
				# 	a &b
				# binary (consistent spacing):
				#	a&b		OK
				#	a & b		OK
				#
				# boiling down to: if there is a space on the right then there
				# should be one on the left.
				#
				# - is the same
				#
				# * is the same only adding:
				# type:
				# 	(foo *)
				#	(foo **)
				#
				} elsif ($op eq '&' or $op eq '-' or $op eq '*') {
					if ($w2 and !$w1) {
						print "need space before that '$op' $at\n";
						print "$herecurr";
						$clean = 0;
					}

				# << and >> may either have or not have spaces both sides
				} elsif ($op eq '<<' or $op eq '>>' or $op eq '+' or $op eq '/' or
					 $op eq '^' or $op eq '|')
				{
					if ($s1 != $s2) {
						print "need consistent spacing around '$op' $at\n";
						print "$herecurr";
						$clean = 0;
					}

				# All the others need spaces both sides.
				} elsif (!$s1 or !$s2) {
					print "need spaces around that '$op' $at\n";
					print "$herecurr";
					$clean = 0;
				}
			}
		}

#need space before brace following if, while, etc
		if ($line=~/\(.*\){/) {
			print "need a space before the brace\n";
			print "$herecurr";
			$clean = 0;
		}

#goto labels aren't indented, allow a single space however
		if ($line=~/^.\s+[A-Za-z\d_]+:/ and
		   !($line=~/^. [A-Za-z\d_]+:/) and !($line=~/^.\s+default:/)) {
			print "labels should not be indented\n";
			print "$herecurr";
			$clean = 0;
		}

# Need a space before open parenthesis after if, while etc
		if ($line=~/(if|while|for|switch)\(/) {
			print "need a space before the open parenthesis\n";
			print "$herecurr";
			$clean = 0;
		}

# Check for illegal assignment in if conditional.
		if ($line=~/(if|while)\s*\(.*[^<>!=]=[^=].*\)/) {
			print "do not use assignment in if condition\n";
			print "$herecurr";
			$clean = 0;
		}

		# Check for }<nl>else {, these must be at the same
		# indent level to be relevant to each other.
		if ($prevline=~/}\s*$/ and $line=~/^.\s*else\s*/ and
						$previndent == $indent) {
			print "else should follow close brace\n";
			print "$hereprev";
			$clean = 0;
		}

		# Check for switch () {<nl>case, these must be at the
		# same indent.  We will only catch the first one, as our
		# context is very small but people tend to be consistent
		# so we will catch them out more often than not.
		if ($prevline=~/\s*switch\s*\(.*\)/ and $line=~/\s*case\s+/
						and $previndent != $indent) {
			print "switch and case should be at the same indent\n";
			print "$hereprev";
			$clean = 0;
		}

#studly caps, commented out until figure out how to distinguish between use of existing and adding new
#		if (($line=~/[\w_][a-z\d]+[A-Z]/) and !($line=~/print/)) {
#		    print "No studly caps, use _\n";
#		    print "$herecurr";
#		    $clean = 0;
#		}

#no spaces allowed after \ in define
		if ($line=~/\#define.*\\\s$/) {
			print("Whitepspace after \\ makes next lines useless\n");
			print "$herecurr";
			$clean = 0;
		}

#warn if <asm/foo.h> is #included and <linux/foo.h> is available.
		if ($tree && $line =~ qr|\s*\#\s*include\s*\<asm\/(.*)\.h\>|) {
			my $checkfile = "include/linux/$1.h";
			if (-f $checkfile) {
				print "Use #include <linux/$1.h> instead of <asm/$1.h>\n";
				print $herecurr;
				$clean = 0;
			}
		}

#if/while/etc brace do not go on next line, unless #defining a do while loop, or if that brace on the next line is for something else
		if ($prevline=~/(if|while|for|switch)\s*\(/) {
			my @opened = $prevline=~/\(/g;
			my @closed = $prevline=~/\)/g;
			my $nr_line = $linenr;
			my $remaining = $realcnt;
			my $next_line = $line;
			my $extra_lines = 0;
			my $display_segment = $prevline;

			while ($remaining > 0 && scalar @opened > scalar @closed) {
				$prevline .= $next_line;
				$display_segment .= "\n" . $next_line;
				$next_line = $lines[$nr_line];
				$nr_line++;
				$remaining--;

				@opened = $prevline=~/\(/g;
				@closed = $prevline=~/\)/g;
			}

			if (($prevline=~/(if|while|for|switch)\s*\(.*\)\s*$/) and ($next_line=~/{/) and
			   !($next_line=~/(if|while|for)/) and !($next_line=~/\#define.*do.*while/)) {
				print "That { should be on the previous line\n";
				print "$display_segment\n$next_line\n\n";
				$clean = 0;
			}
		}

#multiline macros should be enclosed in a do while loop
		if (($prevline=~/\#define.*\\/) and !($prevline=~/do\s+{/) and
		   !($prevline=~/\(\{/) and ($line=~/;\s*\\/) and
		   !($line=~/do.*{/) and !($line=~/\(\{/)) {
			print "Macros with multiple statements should be enclosed in a do - while loop\n";
			print "$hereprev";
			$clean = 0;
		}

# don't include deprecated include files
		for my $inc (@deprecated) {
			if ($line =~ m@\#\s*include\s*\<$inc>@) {
				print "Don't use <$inc>: see Documentation/feature-removal-schedule.txt\n";
				print "$herecurr";
				$clean = 0;
			}
		}

# don't use kernel_thread()
		if ($line =~ /\bkernel_thread\b/) {
			print "Don't use kernel_thread(), use kthread(): see Documentation/feature-removal-schedule.txt\n";
			print "$herecurr";
			$clean = 0;
		}
	}

	if ($chk_patch && !$is_patch) {
		$clean = 0;
		print "Does not appear to be a unified-diff format patch\n";
	}
	if ($is_patch && $chk_signoff && $signoff == 0) {
		$clean = 0;
		print "Missing Signed-off-by: line(s)\n";
	}

	if ($clean == 1 && $quiet == 0) {
		print "Your patch has no obvious style problems and is ready for submission.\n"
	}
	if ($clean == 0 && $quiet == 0) {
		print "Your patch has style problems, please review.  If any of these errors\n";
		print "are false positives report them to the maintainer, see\n";
		print "CHECKPATCH in MAINTAINERS.\n";
	}
	return $clean;
}