checkpatch.pl

sub check_absolute_file {
	my ($absolute, $herecurr) = @_;
	my $file = $absolute;

	##print "absolute<$absolute>\n";

	# See if any suffix of this path is a path within the tree.
	while ($file =~ s@^[^/]*/@@) {
		if (-f "$root/$file") {
			##print "file<$file>\n";
			last;
		}
	}
	if (! -f _)  {
		return 0;
	}

	# It is, so see if the prefix is acceptable.
	my $prefix = $absolute;
	substr($prefix, -length($file)) = '';

	##print "prefix<$prefix>\n";
	if ($prefix ne ".../") {
		WARN("use relative pathname instead of absolute in changelog text\n" . $herecurr);
	}
}

sub process {
	my $filename = shift;

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

	my $length;
	my $indent;
	my $previndent=0;
	my $stashindent=0;

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

	our @report = ();
	our $cnt_lines = 0;
	our $cnt_error = 0;
	our $cnt_warn = 0;
	our $cnt_chk = 0;

	# Trace the real file/line as we go.
	my $realfile = '';
	my $realline = 0;
	my $realcnt = 0;
	my $here = '';
	my $in_comment = 0;
	my $comment_edge = 0;
	my $first_line = 0;
	my $p1_prefix = '';

	my $prev_values = 'E';

	# suppression flags
	my %suppress_ifbraces;
	my %suppress_whiletrailers;

	# Pre-scan the patch sanitizing the lines.
	# Pre-scan the patch looking for any __setup documentation.
	#
	my @setup_docs = ();
	my $setup_docs = 0;

	sanitise_line_reset();
	my $line;
	foreach my $rawline (@rawlines) {
		$linenr++;
		$line = $rawline;

		if ($rawline=~/^\+\+\+\s+(\S+)/) {
			$setup_docs = 0;
			if ($1 =~ m@Documentation/kernel-parameters.txt$@) {
				$setup_docs = 1;
			}
			#next;
		}
		if ($rawline=~/^\@\@ -\d+(?:,\d+)? \+(\d+)(,(\d+))? \@\@/) {
			$realline=$1-1;
			if (defined $2) {
				$realcnt=$3+1;
			} else {
				$realcnt=1+1;
			}
			$in_comment = 0;

			# Guestimate if this is a continuing comment.  Run
			# the context looking for a comment "edge".  If this
			# edge is a close comment then we must be in a comment
			# at context start.
			my $edge;
			my $cnt = $realcnt;
			for (my $ln = $linenr + 1; $cnt > 0; $ln++) {
				next if (defined $rawlines[$ln - 1] &&
					 $rawlines[$ln - 1] =~ /^-/);
				$cnt--;
				#print "RAW<$rawlines[$ln - 1]>\n";
				last if (!defined $rawlines[$ln - 1]);
				if ($rawlines[$ln - 1] =~ m@(/\*|\*/)@ &&
				    $rawlines[$ln - 1] !~ m@"[^"]*(?:/\*|\*/)[^"]*"@) {
					($edge) = $1;
					last;
				}
			}
			if (defined $edge && $edge eq '*/') {
				$in_comment = 1;
			}

			# 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 (!defined $edge &&
			    $rawlines[$linenr] =~ m@^.\s*(?:\*\*+| \*)(?:\s|$)@)
			{
				$in_comment = 1;
			}

			##print "COMMENT:$in_comment edge<$edge> $rawline\n";
			sanitise_line_reset($in_comment);

		} elsif ($realcnt && $rawline =~ /^(?:\+| |$)/) {
			# Standardise the strings and chars within the input to
			# simplify matching -- only bother with positive lines.
			$line = sanitise_line($rawline);
		}
		push(@lines, $line);

		if ($realcnt > 1) {
			$realcnt-- if ($line =~ /^(?:\+| |$)/);
		} else {
			$realcnt = 0;
		}

		#print "==>$rawline\n";
		#print "-->$line\n";

		if ($setup_docs && $line =~ /^\+/) {
			push(@setup_docs, $line);
		}
	}

	$prefix = '';

	$realcnt = 0;
	$linenr = 0;
	foreach my $line (@lines) {
		$linenr++;

		my $rawline = $rawlines[$linenr - 1];
		my $hunk_line = ($realcnt != 0);

#extract the line range in the file after the patch is applied
		if ($line=~/^\@\@ -\d+(?:,\d+)? \+(\d+)(,(\d+))? \@\@/) {
			$is_patch = 1;
			$first_line = $linenr + 1;
			$realline=$1-1;
			if (defined $2) {
				$realcnt=$3+1;
			} else {
				$realcnt=1+1;
			}
			annotate_reset();
			$prev_values = 'E';

			%suppress_ifbraces = ();
			%suppress_whiletrailers = ();
			next;

# track the line number as we move through the hunk, note that
# new versions of GNU diff omit the leading space on completely
# blank context lines so we need to count that too.
		} elsif ($line =~ /^( |\+|$)/) {
			$realline++;
			$realcnt-- if ($realcnt != 0);

			# Measure the line length and indent.
			($length, $indent) = line_stats($rawline);

			# Track the previous line.
			($prevline, $stashline) = ($stashline, $line);
			($previndent, $stashindent) = ($stashindent, $indent);
			($prevrawline, $stashrawline) = ($stashrawline, $rawline);

			#warn "line<$line>\n";

		} elsif ($realcnt == 1) {
			$realcnt--;
		}

#make up the handle for any error we report on this line
		$prefix = "$filename:$realline: " if ($emacs && $file);
		$prefix = "$filename:$linenr: " if ($emacs && !$file);

		$here = "#$linenr: " if (!$file);
		$here = "#$realline: " if ($file);

		# extract the filename as it passes
		if ($line=~/^\+\+\+\s+(\S+)/) {
			$realfile = $1;
			$realfile =~ s@^([^/]*)/@@;

			$p1_prefix = $1;
			if ($tree && $p1_prefix ne '' && -e "$root/$p1_prefix") {
				WARN("patch prefix '$p1_prefix' exists, appears to be a -p0 patch\n");
			}

			if ($realfile =~ m@^include/asm/@) {
				ERROR("do not modify files in include/asm, change architecture specific files in include/asm-<architecture>\n" . "$here$rawline\n");
			}
			next;
		}

		$here .= "FILE: $realfile:$realline:" if ($realcnt != 0);

		my $hereline = "$here\n$rawline\n";
		my $herecurr = "$here\n$rawline\n";
		my $hereprev = "$here\n$prevrawline\n$rawline\n";

		$cnt_lines++ if ($realcnt != 0);

#check the patch for a signoff:
		if ($line =~ /^\s*signed-off-by:/i) {
			# This is a signoff, if ugly, so do not double report.
			$signoff++;
			if (!($line =~ /^\s*Signed-off-by:/)) {
				WARN("Signed-off-by: is the preferred form\n" .
					$herecurr);
			}
			if ($line =~ /^\s*signed-off-by:\S/i) {
				WARN("space required after Signed-off-by:\n" .
					$herecurr);
			}
		}

# Check for wrappage within a valid hunk of the file
		if ($realcnt != 0 && $line !~ m{^(?:\+|-| |\\ No newline|$)}) {
			ERROR("patch seems to be corrupt (line wrapped?)\n" .
				$herecurr) if (!$emitted_corrupt++);
		}

# Check for absolute kernel paths.
		if ($tree) {
			while ($line =~ m{(?:^|\s)(/\S*)}g) {
				my $file = $1;

				if ($file =~ m{^(.*?)(?::\d+)+:?$} &&
				    check_absolute_file($1, $herecurr)) {
					#
				} else {
					check_absolute_file($file, $herecurr);
				}
			}
		}

# UTF-8 regex found at http://www.w3.org/International/questions/qa-forms-utf-8.en.php
		if (($realfile =~ /^$/ || $line =~ /^\+/) &&
		    $rawline !~ m/^$UTF8*$/) {
			my ($utf8_prefix) = ($rawline =~ /^($UTF8*)/);

			my $blank = copy_spacing($rawline);
			my $ptr = substr($blank, 0, length($utf8_prefix)) . "^";
			my $hereptr = "$hereline$ptr\n";

			ERROR("Invalid UTF-8, patch and commit message should be encoded in UTF-8\n" . $hereptr);
		}

# ignore non-hunk lines and lines being removed
		next if (!$hunk_line || $line =~ /^-/);

#trailing whitespace
		if ($line =~ /^\+.*\015/) {
			my $herevet = "$here\n" . cat_vet($rawline) . "\n";
			ERROR("DOS line endings\n" . $herevet);

		} elsif ($rawline =~ /^\+.*\S\s+$/ || $rawline =~ /^\+\s+$/) {
			my $herevet = "$here\n" . cat_vet($rawline) . "\n";
			ERROR("trailing whitespace\n" . $herevet);
		}

# check we are in a valid source file if not then ignore this hunk
		next if ($realfile !~ /\.(h|c|s|S|pl|sh)$/);

#80 column limit
		if ($line =~ /^\+/ && $prevrawline !~ /\/\*\*/ &&
		    $rawline !~ /^.\s*\*\s*\@$Ident\s/ &&
		    $line !~ /^\+\s*printk\s*\(\s*(?:KERN_\S+\s*)?"[X\t]*"\s*(?:,|\)\s*;)\s*$/ &&
		    $length > 80)
		{
			WARN("line over 80 characters\n" . $herecurr);
		}

# check for adding lines without a newline.
		if ($line =~ /^\+/ && defined $lines[$linenr] && $lines[$linenr] =~ /^\\ No newline at end of file/) {
			WARN("adding a line without newline at end of file\n" . $herecurr);
		}

# check we are in a valid source file C or perl if not then ignore this hunk
		next if ($realfile !~ /\.(h|c|pl)$/);

# at the beginning of a line any tabs must come first and anything
# more than 8 must use tabs.
		if ($rawline =~ /^\+\s* \t\s*\S/ ||
		    $rawline =~ /^\+\s*        \s*/) {
			my $herevet = "$here\n" . cat_vet($rawline) . "\n";
			ERROR("code indent should use tabs where possible\n" . $herevet);
		}

# check we are in a valid C source file if not then ignore this hunk
		next if ($realfile !~ /\.(h|c)$/);

# check for RCS/CVS revision markers
		if ($rawline =~ /^\+.*\$(Revision|Log|Id)(?:\$|)/) {
			WARN("CVS style keyword markers, these will _not_ be updated\n". $herecurr);
		}

# Check for potential 'bare' types
		my ($stat, $cond, $line_nr_next, $remain_next, $off_next);
		if ($realcnt && $line =~ /.\s*\S/) {
			($stat, $cond, $line_nr_next, $remain_next, $off_next) =
				ctx_statement_block($linenr, $realcnt, 0);
			$stat =~ s/\n./\n /g;
			$cond =~ s/\n./\n /g;

			my $s = $stat;
			$s =~ s/{.*$//s;

			# Ignore goto labels.
			if ($s =~ /$Ident:\*$/s) {

			# Ignore functions being called
			} elsif ($s =~ /^.\s*$Ident\s*\(/s) {

			# declarations always start with types
			} elsif ($prev_values eq 'E' && $s =~ /^.\s*(?:$Storage\s+)?(?:$Inline\s+)?(?:const\s+)?((?:\s*$Ident)+?)\b(?:\s+$Sparse)?\s*\**\s*(?:$Ident|\(\*[^\)]*\))(?:\s*$Modifier)?\s*(?:;|=|,|\()/s) {
				my $type = $1;
				$type =~ s/\s+/ /g;
				possible($type, "A:" . $s);

			# definitions in global scope can only start with types
			} elsif ($s =~ /^.(?:$Storage\s+)?(?:$Inline\s+)?(?:const\s+)?($Ident)\b\s*(?!:)/s) {
				possible($1, "B:" . $s);
			}

			# any (foo ... *) is a pointer cast, and foo is a type
			while ($s =~ /\(($Ident)(?:\s+$Sparse)*[\s\*]+\s*\)/sg) {
				possible($1, "C:" . $s);
			}

			# Check for any sort of function declaration.
			# int foo(something bar, other baz);
			# void (*store_gdt)(x86_descr_ptr *);
			if ($prev_values eq 'E' && $s =~ /^(.(?:typedef\s*)?(?:(?:$Storage|$Inline)\s*)*\s*$Type\s*(?:\b$Ident|\(\*\s*$Ident\))\s*)\(/s) {
				my ($name_len) = length($1);

				my $ctx = $s;
				substr($ctx, 0, $name_len + 1, '');
				$ctx =~ s/\)[^\)]*$//;

				for my $arg (split(/\s*,\s*/, $ctx)) {
					if ($arg =~ /^(?:const\s+)?($Ident)(?:\s+$Sparse)*\s*\**\s*(:?\b$Ident)?$/s || $arg =~ /^($Ident)$/s) {

						possible($1, "D:" . $s);
					}
				}
			}

		}

#
# Checks which may be anchored in the context.
#

# Check for switch () and associated case and default
# statements should be at the same indent.
		if ($line=~/\bswitch\s*\(.*\)/) {
			my $err = '';
			my $sep = '';
			my @ctx = ctx_block_outer($linenr, $realcnt);
			shift(@ctx);
			for my $ctx (@ctx) {
				my ($clen, $cindent) = line_stats($ctx);
				if ($ctx =~ /^\+\s*(case\s+|default:)/ &&
							$indent != $cindent) {
					$err .= "$sep$ctx\n";
					$sep = '';
				} else {
					$sep = "[...]\n";
				}
			}
			if ($err ne '') {
				ERROR("switch and case should be at the same indent\n$hereline$err");
			}
		}

# 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 ($line =~ /(.*)\b((?:if|while|for|switch)\s*\(|do\b|else\b)/ && $line !~ /^.\s*\#/) {
			my $pre_ctx = "$1$2";

			my ($level, @ctx) = ctx_statement_level($linenr, $realcnt, 0);
			my $ctx_cnt = $realcnt - $#ctx - 1;
			my $ctx = join("\n", @ctx);

			my $ctx_ln = $linenr;
			my $ctx_skip = $realcnt;

			while ($ctx_skip > $ctx_cnt || ($ctx_skip == $ctx_cnt &&
					defined $lines[$ctx_ln - 1] &&
					$lines[$ctx_ln - 1] =~ /^-/)) {
				##print "SKIP<$ctx_skip> CNT<$ctx_cnt>\n";
				$ctx_skip-- if (!defined $lines[$ctx_ln - 1] || $lines[$ctx_ln - 1] !~ /^-/);
				$ctx_ln++;
			}

			#print "realcnt<$realcnt> ctx_cnt<$ctx_cnt>\n";
			#print "pre<$pre_ctx>\nline<$line>\nctx<$ctx>\nnext<$lines[$ctx_ln - 1]>\n";

			if ($ctx !~ /{\s*/ && defined($lines[$ctx_ln -1]) && $lines[$ctx_ln - 1] =~ /^\+\s*{/) {
				ERROR("that open brace { should be on the previous line\n" .
					"$here\n$ctx\n$lines[$ctx_ln - 1]\n");
			}
			if ($level == 0 && $pre_ctx !~ /}\s*while\s*\($/ &&
			    $ctx =~ /\)\s*\;\s*$/ &&
			    defined $lines[$ctx_ln - 1])
			{
				my ($nlength, $nindent) = line_stats($lines[$ctx_ln - 1]);
				if ($nindent > $indent) {
					WARN("trailing semicolon indicates no statements, indent implies otherwise\n" .
						"$here\n$ctx\n$lines[$ctx_ln - 1]\n");
				}
			}
		}

# Check relative indent for conditionals and blocks.
		if ($line =~ /\b(?:(?:if|while|for)\s*\(|do\b)/ && $line !~ /^.\s*#/ && $line !~ /\}\s*while\s*/) {
			my ($s, $c) = ($stat, $cond);

			substr($s, 0, length($c), '');

			# Make sure we remove the line prefixes as we have
			# none on the first line, and are going to readd them
			# where necessary.
			$s =~ s/\n./\n/gs;

			# Find out how long the conditional actually is.
			my @newlines = ($c =~ /\n/gs);
			my $cond_lines = 1 + $#newlines;

			# We want to check the first line inside the block
			# starting at the end of the conditional, so remove:
			#  1) any blank line termination
			#  2) any opening brace { on end of the line
			#  3) any do (...) {
			my $continuation = 0;
			my $check = 0;
			$s =~ s/^.*\bdo\b//;
			$s =~ s/^\s*{//;
			if ($s =~ s/^\s*\\//) {
				$continuation = 1;
			}
			if ($s =~ s/^\s*?\n//) {
				$check = 1;
				$cond_lines++;
			}

			# Also ignore a loop construct at the end of a
			# preprocessor statement.
			if (($prevline =~ /^.\s*#\s*define\s/ ||
			    $prevline =~ /\\\s*$/) && $continuation == 0) {
				$check = 0;
			}

			my $cond_ptr = -1;
			$continuation = 0;
			while ($cond_ptr != $cond_lines) {
				$cond_ptr = $cond_lines;

				# If we see an #else/#elif then the code
				# is not linear.
				if ($s =~ /^\s*\#\s*(?:else|elif)/) {
					$check = 0;
				}

				# Ignore:
				#  1) blank lines, they should be at 0,
				#  2) preprocessor lines, and
				#  3) labels.
				if ($continuation ||
				    $s =~ /^\s*?\n/ ||
				    $s =~ /^\s*#\s*?/ ||
				    $s =~ /^\s*$Ident\s*:/) {
					$continuation = ($s =~ /^.*?\\\n/) ? 1 : 0;
					$s =~ s/^.*?\n//;
					$cond_lines++;
				}
			}

			my (undef, $sindent) = line_stats("+" . $s);
			my $stat_real = raw_line($linenr, $cond_lines);

			# Check if either of these lines are modified, else
			# this is not this patch's fault.
			if (!defined($stat_real) ||
			    $stat !~ /^\+/ && $stat_real !~ /^\+/) {
				$check = 0;
			}
			if (defined($stat_real) && $cond_lines > 1) {
				$stat_real = "[...]\n$stat_real";
			}

			#print "line<$line> prevline<$prevline> indent<$indent> sindent<$sindent> check<$check> continuation<$continuation> s<$s> cond_lines<$cond_lines> stat_real<$stat_real> stat<$stat>\n";

			if ($check && (($sindent % 8) != 0 ||
			    ($sindent <= $indent && $s ne ''))) {
				WARN("suspect code indent for conditional statements ($indent, $sindent)\n" . $herecurr . "$stat_real\n");
			}
		}

		# Track the 'values' across context and added lines.
		my $opline = $line; $opline =~ s/^./ /;
		my ($curr_values, $curr_vars) =
				annotate_values($opline . "\n", $prev_values);
		$curr_values = $prev_values . $curr_values;
		if ($dbg_values) {
			my $outline = $opline; $outline =~ s/\t/ /g;
			print "$linenr > .$outline\n";
			print "$linenr > $curr_values\n";
			print "$linenr >  $curr_vars\n";
		}
		$prev_values = substr($curr_values, -1);

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

# TEST: allow direct testing of the type matcher.
		if ($dbg_type) {
			if ($line =~ /^.\s*$Declare\s*$/) {
				ERROR("TEST: is type\n" . $herecurr);
			} elsif ($dbg_type > 1 && $line =~ /^.+($Declare)/) {
				ERROR("TEST: is not type ($1 is)\n". $herecurr);
			}
			next;
		}
# TEST: allow direct testing of the attribute matcher.
		if ($dbg_attr) {
			if ($line =~ /^.\s*$Attribute\s*$/) {
				ERROR("TEST: is attr\n" . $herecurr);
			} elsif ($dbg_attr > 1 && $line =~ /^.+($Attribute)/) {
				ERROR("TEST: is not attr ($1 is)\n". $herecurr);
			}
			next;
		}

# check for initialisation to aggregates open brace on the next line
		if ($prevline =~ /$Declare\s*$Ident\s*=\s*$/ &&
		    $line =~ /^.\s*{/) {
			ERROR("that open brace { should be on the previous line\n" . $hereprev);
		}

#
# Checks which are anchored on the added line.
#

# check for malformed paths in #include statements (uses RAW line)
		if ($rawline =~ m{^.\s*\#\s*include\s+[<"](.*)[">]}) {
			my $path = $1;
			if ($path =~ m{//}) {
				ERROR("malformed #include filename\n" .
					$herecurr);
			}
		}

# no C99 // comments
		if ($line =~ m{//}) {
			ERROR("do not use C99 // comments\n" . $herecurr);
		}
		# Remove C99 comments.
		$line =~ s@//.*@@;
		$opline =~ s@//.*@@;

#EXPORT_SYMBOL should immediately follow its function closing }.
		if (($line =~ /EXPORT_SYMBOL.*\((.*)\)/) ||
		    ($line =~ /EXPORT_UNUSED_SYMBOL.*\((.*)\)/)) {
			my $name = $1;
			if ($prevline !~ /(?:
				^.}|
				^.DEFINE_$Ident\(\Q$name\E\)|
				^.DECLARE_$Ident\(\Q$name\E\)|
				^.LIST_HEAD\(\Q$name\E\)|
				^.$Type\s*\(\s*\*\s*\Q$name\E\s*\)\s*\(|
				\b\Q$name\E(?:\s+$Attribute)?\s*(?:;|=|\[)
			    )/x) {
				WARN("EXPORT_SYMBOL(foo); should immediately follow its function/variable\n" . $herecurr);
			}
		}

# check for external initialisers.
		if ($line =~ /^.$Type\s*$Ident\s*(?:\s+$Modifier)*\s*=\s*(0|NULL|false)\s*;/) {
			ERROR("do not initialise externals to 0 or NULL\n" .
				$herecurr);
		}
# check for static initialisers.
		if ($line =~ /\s*static\s.*=\s*(0|NULL|false)\s*;/) {
			ERROR("do not initialise statics to 0 or NULL\n" .
				$herecurr);
		}

# check for new typedefs, only function parameters and sparse annotations
# make sense.
		if ($line =~ /\btypedef\s/ &&
		    $line !~ /\btypedef\s+$Type\s+\(\s*\*?$Ident\s*\)\s*\(/ &&
		    $line !~ /\btypedef\s+$Type\s+$Ident\s*\(/ &&
		    $line !~ /\b$typeTypedefs\b/ &&
		    $line !~ /\b__bitwise(?:__|)\b/) {
			WARN("do not add new typedefs\n" . $herecurr);
		}

# * goes on variable not on type
		# (char*[ const])
		if ($line =~ m{\($NonptrType(\s*\*[\s\*]*(?:$Modifier\s*)*)\)}) {
			my ($from, $to) = ($1, $1);

			# Should start with a space.
			$to =~ s/^(\S)/ $1/;
			# Should not end with a space.
			$to =~ s/\s+$//;
			# '*'s should not have spaces between.
			while ($to =~ s/(.)\s\*/$1\*/) {
			}

			#print "from<$from> to<$to>\n";
			if ($from ne $to) {
				ERROR("\"(foo$from)\" should be \"(foo$to)\"\n" .  $herecurr);
			}
		} elsif ($line =~ m{\b$NonptrType(\s*\*[\s\*]*(?:$Modifier\s*)?)($Ident)}) {
			my ($from, $to, $ident) = ($1, $1, $2);

			# Should start with a space.
			$to =~ s/^(\S)/ $1/;
			# Should not end with a space.
			$to =~ s/\s+$//;
			# '*'s should not have spaces between.
			while ($to =~ s/(.)\s\*/$1\*/) {
			}
			# Modifiers should have spaces.
			$to =~ s/(\b$Modifier$)/$1 /;

			#print "from<$from> to<$to>\n";
			if ($from ne $to) {
				ERROR("\"foo${from}bar\" should be \"foo${to}bar\"\n" .  $herecurr);
			}
		}

# # 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;
# 		}

		if ($line =~ /\bLINUX_VERSION_CODE\b/) {
			WARN("LINUX_VERSION_CODE should be avoided, code should be for the version to which it is merged\n" . $herecurr);
		}

# printk should use KERN_* levels.  Note that follow on printk's on the
# same line do not need a level, so we use the current block context
# to try and find and validate the current printk.  In summary the current
# printk includes all preceeding printk's which have no newline on the end.
# we assume the first bad printk is the one to report.
		if ($line =~ /\bprintk\((?!KERN_)\s*"/) {
			my $ok = 0;
			for (my $ln = $linenr - 1; $ln >= $first_line; $ln--) {
				#print "CHECK<$lines[$ln - 1]\n";
				# we have a preceeding printk if it ends
				# with "\n" ignore it, else it is to blame
				if ($lines[$ln - 1] =~ m{\bprintk\(}) {
					if ($rawlines[$ln - 1] !~ m{\\n"}) {
						$ok = 1;
					}
					last;
				}
			}
			if ($ok == 0) {
				WARN("printk() should include KERN_ facility level\n" . $herecurr);
			}
		}

# function brace can't be on same line, except for #defines of do while,
# or if closed on same line
		if (($line=~/$Type\s*$Ident\(.*\).*\s{/) and
		    !($line=~/\#\s*define.*do\s{/) and !($line=~/}/)) {
			ERROR("open brace '{' following function declarations go on the next line\n" . $herecurr);
		}

# open braces for enum, union and struct go on the same line.
		if ($line =~ /^.\s*{/ &&
		    $prevline =~ /^.\s*(?:typedef\s+)?(enum|union|struct)(?:\s+$Ident)?\s*$/) {
			ERROR("open brace '{' following $1 go on the same line\n" . $hereprev);
		}

# check for spacing round square brackets; allowed:
#  1. with a type on the left -- int [] a;
#  2. at the beginning of a line for slice initialisers -- [0...10] = 5,
#  3. inside a curly brace -- = { [0...10] = 5 }
		while ($line =~ /(.*?\s)\[/g) {
			my ($where, $prefix) = ($-[1], $1);
			if ($prefix !~ /$Type\s+$/ &&
			    ($where != 0 || $prefix !~ /^.\s+$/) &&
			    $prefix !~ /{\s+$/) {
				ERROR("space prohibited before open square bracket '['\n" . $herecurr);
			}
		}

# check for spaces between functions and their parentheses.
		while ($line =~ /($Ident)\s+\(/g) {
			my $name = $1;
			my $ctx_before = substr($line, 0, $-[1]);
			my $ctx = "$ctx_before$name";

			# Ignore those directives where spaces _are_ permitted.
			if ($name =~ /^(?:
				if|for|while|switch|return|case|
				volatile|__volatile__|
				__attribute__|format|__extension__|
				asm|__asm__)$/x)
			{

			# cpp #define statements have non-optional spaces, ie
			# if there is a space between the name and the open
			# parenthesis it is simply not a parameter group.
			} elsif ($ctx_before =~ /^.\s*\#\s*define\s*$/) {

			# cpp #elif statement condition may start with a (
			} elsif ($ctx =~ /^.\s*\#\s*elif\s*$/) {

			# If this whole things ends with a type its most
			# likely a typedef for a function.
			} elsif ($ctx =~ /$Type$/) {

			} else {
				WARN("space prohibited between function name and open parenthesis '('\n" . $herecurr);
			}
		}
# Check operator spacing.
		if (!($line=~/\#\s*include/)) {
			my $ops = qr{
				<<=|>>=|<=|>=|==|!=|
				\+=|-=|\*=|\/=|%=|\^=|\|=|&=|
				=>|->|<<|>>|<|>|=|!|~|
				&&|\|\||,|\^|\+\+|--|&|\||\+|-|\*|\/|%|
				\?|:
			}x;
			my @elements = split(/($ops|;)/, $opline);
			my $off = 0;

			my $blank = copy_spacing($opline);

			for (my $n = 0; $n < $#elements; $n += 2) {
				$off += length($elements[$n]);

				# Pick up the preceeding and succeeding characters.
				my $ca = substr($opline, 0, $off);
				my $cc = '';
				if (length($opline) >= ($off + length($elements[$n + 1]))) {
					$cc = substr($opline, $off + length($elements[$n + 1]));
				}
				my $cb = "$ca$;$cc";

				my $a = '';
				$a = 'V' if ($elements[$n] ne '');
				$a = 'W' if ($elements[$n] =~ /\s$/);
				$a = 'C' if ($elements[$n] =~ /$;$/);
				$a = 'B' if ($elements[$n] =~ /(\[|\()$/);
				$a = 'O' if ($elements[$n] eq '');
				$a = 'E' if ($ca =~ /^\s*$/);

				my $op = $elements[$n + 1];

				my $c = '';
				if (defined $elements[$n + 2]) {
					$c = 'V' if ($elements[$n + 2] ne '');
					$c = 'W' if ($elements[$n + 2] =~ /^\s/);
					$c = 'C' if ($elements[$n + 2] =~ /^$;/);
					$c = 'B' if ($elements[$n + 2] =~ /^(\)|\]|;)/);
					$c = 'O' if ($elements[$n + 2] eq '');
					$c = 'E' if ($elements[$n + 2] =~ /\s*\\$/);
				} else {
					$c = 'E';
				}

				my $ctx = "${a}x${c}";

				my $at = "(ctx:$ctx)";

				my $ptr = substr($blank, 0, $off) . "^";
				my $hereptr = "$hereline$ptr\n";

				# Pull out the value of this operator.
				my $op_type = substr($curr_values, $off + 1, 1);

				# Get the full operator variant.
				my $opv = $op . substr($curr_vars, $off, 1);

				# Ignore operators passed as parameters.
				if ($op_type ne 'V' &&
				    $ca =~ /\s$/ && $cc =~ /^\s*,/) {

#				# Ignore comments
#				} elsif ($op =~ /^$;+$/) {

				# ; should have either the end of line or a space or \ after it
				} elsif ($op eq ';') {
					if ($ctx !~ /.x[WEBC]/ &&
					    $cc !~ /^\\/ && $cc !~ /^;/) {
						ERROR("space required after that '$op' $at\n" . $hereptr);
					}

				# // is a comment
				} elsif ($op eq '//') {

				# No spaces for:
				#   ->
				#   :   when part of a bitfield
				} elsif ($op eq '->' || $opv eq ':B') {
					if ($ctx =~ /Wx.|.xW/) {
						ERROR("spaces prohibited around that '$op' $at\n" . $hereptr);
					}

				# , must have a space on the right.
				} elsif ($op eq ',') {
					if ($ctx !~ /.x[WEC]/ && $cc !~ /^}/) {
						ERROR("space required after that '$op' $at\n" . $hereptr);
					}

				# '*' as part of a type definition -- reported already.
				} elsif ($opv eq '*_') {
					#warn "'*' is part of type\n";

				# unary operators should have a space before and
				# none after.  May be left adjacent to another
				# unary operator, or a cast
				} elsif ($op eq '!' || $op eq '~' ||
					 $opv eq '*U' || $opv eq '-U' ||
					 $opv eq '&U' || $opv eq '&&U') {
					if ($ctx !~ /[WEBC]x./ && $ca !~ /(?:\)|!|~|\*|-|\&|\||\+\+|\-\-|\{)$/) {
						ERROR("space required before that '$op' $at\n" . $hereptr);
					}
					if ($op eq '*' && $cc =~/\s*const\b/) {
						# A unary '*' may be const

					} elsif ($ctx =~ /.xW/) {
						ERROR("space prohibited after that '$op' $at\n" . $hereptr);
					}

				# unary ++ and unary -- are allowed no space on one side.
				} elsif ($op eq '++' or $op eq '--') {
					if ($ctx !~ /[WEOBC]x[^W]/ && $ctx !~ /[^W]x[WOBEC]/) {
						ERROR("space required one side of that '$op' $at\n" . $hereptr);
					}
					if ($ctx =~ /Wx[BE]/ ||
					    ($ctx =~ /Wx./ && $cc =~ /^;/)) {
						ERROR("space prohibited before that '$op' $at\n" . $hereptr);
					}
					if ($ctx =~ /ExW/) {
						ERROR("space prohibited after that '$op' $at\n" . $hereptr);
					}


				# << 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 '+' or $op eq '-' or
					 $op eq '*' or $op eq '/' or
					 $op eq '%')
				{
					if ($ctx =~ /Wx[^WCE]|[^WCE]xW/) {
						ERROR("need consistent spacing around '$op' $at\n" .
							$hereptr);
					}

				# A colon needs no spaces before when it is
				# terminating a case value or a label.
				} elsif ($opv eq ':C' || $opv eq ':L') {
					if ($ctx =~ /Wx./) {
						ERROR("space prohibited before that '$op' $at\n" . $hereptr);
					}

				# All the others need spaces both sides.
				} elsif ($ctx !~ /[EWC]x[CWE]/) {
					my $ok = 0;

					# Ignore email addresses <foo@bar>
					if (($op eq '<' &&
					     $cc =~ /^\S+\@\S+>/) ||
					    ($op eq '>' &&
					     $ca =~ /<\S+\@\S+$/))
					{
					    	$ok = 1;
					}

					# Ignore ?:
					if (($opv eq ':O' && $ca =~ /\?$/) ||
					    ($op eq '?' && $cc =~ /^:/)) {
					    	$ok = 1;
					}

					if ($ok == 0) {
						ERROR("spaces required around that '$op' $at\n" . $hereptr);
					}
				}
				$off += length($elements[$n + 1]);
			}
		}

# check for multiple assignments
		if ($line =~ /^.\s*$Lval\s*=\s*$Lval\s*=(?!=)/) {
			CHK("multiple assignments should be avoided\n" . $herecurr);
		}

## # check for multiple declarations, allowing for a function declaration
## # continuation.
## 		if ($line =~ /^.\s*$Type\s+$Ident(?:\s*=[^,{]*)?\s*,\s*$Ident.*/ &&
## 		    $line !~ /^.\s*$Type\s+$Ident(?:\s*=[^,{]*)?\s*,\s*$Type\s*$Ident.*/) {
##
## 			# Remove any bracketed sections to ensure we do not
## 			# falsly report the parameters of functions.
## 			my $ln = $line;
## 			while ($ln =~ s/\([^\(\)]*\)//g) {
## 			}
## 			if ($ln =~ /,/) {
## 				WARN("declaring multiple variables together should be avoided\n" . $herecurr);
## 			}
## 		}

#need space before brace following if, while, etc
		if (($line =~ /\(.*\){/ && $line !~ /\($Type\){/) ||
		    $line =~ /do{/) {
			ERROR("space required before the open brace '{'\n" . $herecurr);
		}

# closing brace should have a space following it when it has anything
# on the line
		if ($line =~ /}(?!(?:,|;|\)))\S/) {
			ERROR("space required after that close brace '}'\n" . $herecurr);
		}

# check spacing on square brackets
		if ($line =~ /\[\s/ && $line !~ /\[\s*$/) {
			ERROR("space prohibited after that open square bracket '['\n" . $herecurr);
		}
		if ($line =~ /\s\]/) {
			ERROR("space prohibited before that close square bracket ']'\n" . $herecurr);
		}

# check spacing on parentheses
		if ($line =~ /\(\s/ && $line !~ /\(\s*(?:\\)?$/ &&
		    $line !~ /for\s*\(\s+;/) {
			ERROR("space prohibited after that open parenthesis '('\n" . $herecurr);
		}
		if ($line =~ /(\s+)\)/ && $line !~ /^.\s*\)/ &&
		    $line !~ /for\s*\(.*;\s+\)/ &&
		    $line !~ /:\s+\)/) {
			ERROR("space prohibited before that close parenthesis ')'\n" . $herecurr);
		}

#goto labels aren't indented, allow a single space however
		if ($line=~/^.\s+[A-Za-z\d_]+:(?![0-9]+)/ and
		   !($line=~/^. [A-Za-z\d_]+:/) and !($line=~/^.\s+default:/)) {
			WARN("labels should not be indented\n" . $herecurr);
		}

# Return is not a function.
		if (defined($stat) && $stat =~ /^.\s*return(\s*)(\(.*);/s) {
			my $spacing = $1;
			my $value = $2;

			# Flatten any parentheses and braces
			$value =~ s/\)\(/\) \(/g;
			while ($value =~ s/\([^\(\)]*\)/1/) {
			}

			if ($value =~ /^(?:$Ident|-?$Constant)$/) {
				ERROR("return is not a function, parentheses are not required\n" . $herecurr);

			} elsif ($spacing !~ /\s+/) {
				ERROR("space required before the open parenthesis '('\n" . $herecurr);
			}
		}

# Need a space before open parenthesis after if, while etc
		if ($line=~/\b(if|while|for|switch)\(/) {