linux/scripts/checkpatch.pl

#!/usr/bin/perl -w
# (c) 2001, Dave Jones. <davej@codemonkey.org.uk> (the file handling bit)
# (c) 2005, Joel Schopp <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;
$P =~ s@.*/@@g;

my $V = '0.08';

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

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

my $exit = 0;

if ($#ARGV < 0) {
	print "usage: $P [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 @dep_includes = ();
my @dep_functions = ();
my $removal = 'Documentation/feature-removal-schedule.txt';
if ($tree && -f $removal) {
	open(REMOVE, "<$removal") || die "$P: $removal: open failed - $!\n";
	while (<REMOVE>) {
		if (/^Check:\s+(.*\S)/) {
			for my $entry (split(/[, ]+/, $1)) {
				if ($entry =~ m@include/(.*)@) {
					push(@dep_includes, $1);

				} elsif ($entry !~ m@/@) {
					push(@dep_functions, $entry);
				}
			}
		}
	}
}

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

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 line_stats {
	my ($line) = @_;

	# Drop the diff line leader and expand tabs
	$line =~ s/^.//;
	$line = expand_tabs($line);

	# Pick the indent from the front of the line.
	my ($white) = ($line =~ /^(\s*)/);

	return (length($line), length($white));
}

sub sanitise_line {
	my ($line) = @_;

	my $res = '';
	my $l = '';

	my $quote = '';

	foreach my $c (split(//, $line)) {
		if ($l ne "\\" && ($c eq "'" || $c eq '"')) {
			if ($quote eq '') {
				$quote = $c;
				$res .= $c;
				$l = $c;
				next;
			} elsif ($quote eq $c) {
				$quote = '';
			}
		}
		if ($quote && $c ne "\t") {
			$res .= "X";
		} else {
			$res .= $c;
		}

		$l = $c;
	}

	return $res;
}

sub ctx_block_get {
	my ($linenr, $remain, $outer, $open, $close, $off) = @_;
	my $line;
	my $start = $linenr - 1;
	my $blk = '';
	my @o;
	my @c;
	my @res = ();

	my $level = 0;
	for ($line = $start; $remain > 0; $line++) {
		next if ($rawlines[$line] =~ /^-/);
		$remain--;

		$blk .= $rawlines[$line];
		foreach my $c (split(//, $rawlines[$line])) {
			##print "C<$c>L<$level><$open$close>O<$off>\n";
			if ($off > 0) {
				$off--;
				next;
			}

			if ($c eq $close && $level > 0) {
				$level--;
				last if ($level == 0);
			} elsif ($c eq $open) {
				$level++;
			}
		}

		if (!$outer || $level <= 1) {
			push(@res, $rawlines[$line]);
		}

		last if ($level == 0);
	}

	return ($level, @res);
}
sub ctx_block_outer {
	my ($linenr, $remain) = @_;

	my ($level, @r) = ctx_block_get($linenr, $remain, 1, '{', '}', 0);
	return @r;
}
sub ctx_block {
	my ($linenr, $remain) = @_;

	my ($level, @r) = ctx_block_get($linenr, $remain, 0, '{', '}', 0);
	return @r;
}
sub ctx_statement {
	my ($linenr, $remain, $off) = @_;

	my ($level, @r) = ctx_block_get($linenr, $remain, 0, '(', ')', $off);
	return @r;
}
sub ctx_block_level {
	my ($linenr, $remain) = @_;

	return ctx_block_get($linenr, $remain, 0, '{', '}', 0);
}

sub ctx_locate_comment {
	my ($first_line, $end_line) = @_;

	# Catch a comment on the end of the line itself.
	my ($current_comment) = ($rawlines[$end_line - 1] =~ m@.*(/\*.*\*/)\s*$@);
	return $current_comment if (defined $current_comment);

	# Look through the context and try and figure out if there is a
	# comment.
	my $in_comment = 0;
	$current_comment = '';
	for (my $linenr = $first_line; $linenr < $end_line; $linenr++) {
		my $line = $rawlines[$linenr - 1];
		#warn "           $line\n";
		if ($linenr == $first_line and $line =~ m@^.\s*\*@) {
			$in_comment = 1;
		}
		if ($line =~ m@/\*@) {
			$in_comment = 1;
		}
		if (!$in_comment && $current_comment ne '') {
			$current_comment = '';
		}
		$current_comment .= $line . "\n" if ($in_comment);
		if ($line =~ m@\*/@) {
			$in_comment = 0;
		}
	}

	chomp($current_comment);
	return($current_comment);
}
sub ctx_has_comment {
	my ($first_line, $end_line) = @_;
	my $cmt = ctx_locate_comment($first_line, $end_line);

	##print "LINE: $rawlines[$end_line - 1 ]\n";
	##print "CMMT: $cmt\n";

	return ($cmt ne '');
}

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

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

	return $vet;
}

my @report = ();
sub report {
	push(@report, $_[0]);
}
sub report_dump {
	@report;
}
sub ERROR {
	report("ERROR: $_[0]\n");
	our $clean = 0;
}
sub WARN {
	report("WARNING: $_[0]\n");
	our $clean = 0;
}
sub CHK {
	report("CHECK: $_[0]\n");
	our $clean = 0;
}

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

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

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

	our $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;

	my $Ident	= qr{[A-Za-z\d_]+};
	my $Storage	= qr{extern|static};
	my $Sparse	= qr{__user|__kernel|__force|__iomem};
	my $NonptrType	= qr{
				\b
				(?:const\s+)?
				(?:unsigned\s+)?
				(?:
					void|
					char|
					short|
					int|
					long|
					unsigned|
					float|
					double|
					long\s+int|
					long\s+long|
					long\s+long\s+int|
					u8|u16|u32|u64|
					s8|s16|s32|s64|
					struct\s+$Ident|
					union\s+$Ident|
					enum\s+$Ident|
					${Ident}_t
				)
				(?:\s+$Sparse)*
				\b
			  }x;
	my $Type	= qr{
				\b$NonptrType\b
				(?:\s*\*+\s*const|\s*\*+)?
			  }x;
	my $Declare	= qr{(?:$Storage\s+)?$Type};
	my $Attribute	= qr{const|__read_mostly|__init|__initdata|__meminit};

	my $Member	= qr{->$Ident|\.$Ident|\[[^]]*\]};
	my $Lval	= qr{$Ident(?:$Member)*};

	# Pre-scan the patch looking for any __setup documentation.
	my @setup_docs = ();
	my $setup_docs = 0;
	foreach my $line (@lines) {
		if ($line=~/^\+\+\+\s+(\S+)/) {
			$setup_docs = 0;
			if ($1 =~ m@Documentation/kernel-parameters.txt$@) {
				$setup_docs = 1;
			}
			next;
		}

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

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

		my $rawline = $line;

#extract the filename as it passes
		if ($line=~/^\+\+\+\s+(\S+)/) {
			$realfile=$1;
			$realfile =~ s@^[^/]*/@@;
			$in_comment = 0;
			next;
		}
#extract the line range in the file after the patch is applied
		if ($line=~/^\@\@ -\d+,\d+ \+(\d+)(,(\d+))? \@\@/) {
			$is_patch = 1;
			$first_line = $linenr + 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, note that
# new versions of GNU diff omit the leading space on completely
# blank context lines so we need to count that too.
		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 ($linenr == $first_line and $line =~ m@^.\s*\*@) {
				$in_comment = 1;
			}
			if ($line =~ m@/\*@) {
				$in_comment = 1;
			}
			if ($line =~ m@\*/@) {
				$in_comment = 0;
			}

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

			# Track the previous line.
			($prevline, $stashline) = ($stashline, $line);
			($previndent, $stashindent) = ($stashindent, $indent);
		} elsif ($realcnt == 1) {
			$realcnt--;
		}

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

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

#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("need space after Signed-off-by:\n" .
					$herecurr);
			}
		}

# Check for wrappage within a valid hunk of the file
		if ($realcnt != 0 && $line !~ m{^(?:\+|-| |$)}) {
			ERROR("patch seems to be corrupt (line wrapped?)\n" .
				$herecurr);
		}

# UTF-8 regex found at http://www.w3.org/International/questions/qa-forms-utf-8.en.php
		if (($realfile =~ /^$/ || $line =~ /^\+/) &&
		     !($line =~ m/^(
				[\x09\x0A\x0D\x20-\x7E]              # ASCII
				| [\xC2-\xDF][\x80-\xBF]             # non-overlong 2-byte
				|  \xE0[\xA0-\xBF][\x80-\xBF]        # excluding overlongs
				| [\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}  # straight 3-byte
				|  \xED[\x80-\x9F][\x80-\xBF]        # excluding surrogates
				|  \xF0[\x90-\xBF][\x80-\xBF]{2}     # planes 1-3
				| [\xF1-\xF3][\x80-\xBF]{3}          # planes 4-15
				|  \xF4[\x80-\x8F][\x80-\xBF]{2}     # plane 16
				)*$/x )) {
			ERROR("Invalid UTF-8\n" . $herecurr);
		}

#ignore lines being removed
		if ($line=~/^-/) {next;}

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

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

# 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";
			ERROR("use tabs not spaces\n" . $herevet);
		}

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

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

# Standardise the strings and chars within the input to simplify matching.
		$line = sanitise_line($line);

#
# 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$hereline\n$err\n");
			}
		}

# 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)/ && $line !~ /^.#/) {
			my @ctx = ctx_statement($linenr, $realcnt, 0);
			my $ctx_ln = $linenr + $#ctx + 1;
			my $ctx_cnt = $realcnt - $#ctx - 1;
			my $ctx = join("\n", @ctx);

			while ($ctx_cnt > 0 && $lines[$ctx_ln - 1] =~ /^-/) {
				$ctx_ln++;
				$ctx_cnt--;
			}
			##warn "line<$line>\nctx<$ctx>\nnext<$lines[$ctx_ln - 1]>";

			if ($ctx !~ /{\s*/ && $ctx_cnt > 0 && $lines[$ctx_ln - 1] =~ /^\+\s*{/) {
				ERROR("That open brace { should be on the previous line\n" .
					"$here\n$ctx\n$lines[$ctx_ln - 1]");
			}
		}

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

# TEST: allow direct testing of the type matcher.
		if ($tst_type && $line =~ /^.$Declare$/) {
			ERROR("TEST: is type $Declare\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*include\s+[<"](.*)[">]}) {
			my $path = $1;
			if ($path =~ m{//}) {
				ERROR("malformed #include filename\n" .
					$herecurr);
			}
			# Sanitise this special form of string.
			$path = 'X' x length($path);
			$line =~ s{\<.*\>}{<$path>};
		}

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

#EXPORT_SYMBOL should immediately follow its function closing }.
		if (($line =~ /EXPORT_SYMBOL.*\((.*)\)/) ||
		    ($line =~ /EXPORT_UNUSED_SYMBOL.*\((.*)\)/)) {
			my $name = $1;
			if (($prevline !~ /^}/) &&
			   ($prevline !~ /^\+}/) &&
			   ($prevline !~ /^ }/) &&
			   ($prevline !~ /\s$name(?:\s+$Attribute)?\s*(?:;|=)/)) {
				WARN("EXPORT_SYMBOL(foo); should immediately follow its function/variable\n" . $herecurr);
			}
		}

# check for external initialisers.
		if ($line =~ /^.$Type\s*$Ident\s*=\s*(0|NULL);/) {
			ERROR("do not initialise externals to 0 or NULL\n" .
				$herecurr);
		}
# check for static initialisers.
		if ($line =~ /\s*static\s.*=\s*(0|NULL);/) {
			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 !~ /\b__bitwise(?:__|)\b/) {
			WARN("do not add new typedefs\n" . $herecurr);
		}

# * goes on variable not on type
		if ($line =~ m{\($NonptrType(\*+)(?:\s+const)?\)}) {
			ERROR("\"(foo$1)\" should be \"(foo $1)\"\n" .
				$herecurr);

		} elsif ($line =~ m{\($NonptrType\s+(\*+)(?!\s+const)\s+\)}) {
			ERROR("\"(foo $1 )\" should be \"(foo $1)\"\n" .
				$herecurr);

		} elsif ($line =~ m{$NonptrType(\*+)(?:\s+$Attribute)?\s+[A-Za-z\d_]+}) {
			ERROR("\"foo$1 bar\" should be \"foo $1bar\"\n" .
				$herecurr);

		} elsif ($line =~ m{$NonptrType\s+(\*+)(?!\s+$Attribute)\s+[A-Za-z\d_]+}) {
			ERROR("\"foo $1 bar\" should be \"foo $1bar\"\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;
# 		}

# 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*[A-Za-z\d_]+\(.*\).* {/) and
		    !($line=~/\#define.*do\s{/) and !($line=~/}/)) {
			ERROR("open brace '{' following function declarations go on the next line\n" . $herecurr);
		}

# check for spaces between functions and their parentheses.
		if ($line =~ /($Ident)\s+\(/ &&
		    $1 !~ /^(?:if|for|while|switch|return|volatile)$/ &&
		    $line !~ /$Type\s+\(/ && $line !~ /^.\#\s*define\b/) {
			ERROR("no space between function name and open parenthesis '('\n" . $herecurr);
		}
# Check operator spacing.
		# Note we expand the line with the leading + as the real
		# line will be displayed with the leading + and the tabs
		# will therefore also expand that way.
		my $opline = $line;
		$opline = expand_tabs($opline);
		$opline =~ s/^./ /;
		if (!($line=~/\#\s*include/)) {
			my @elements = split(/(<<=|>>=|<=|>=|==|!=|\+=|-=|\*=|\/=|%=|\^=|\|=|&=|=>|->|<<|>>|<|>|=|!|~|&&|\|\||,|\^|\+\+|--|;|&|\||\+|-|\*|\/\/|\/)/, $opline);
			my $off = 0;
			for (my $n = 0; $n < $#elements; $n += 2) {
				$off += length($elements[$n]);

				my $a = '';
				$a = 'V' if ($elements[$n] ne '');
				$a = 'W' if ($elements[$n] =~ /\s$/);
				$a = 'B' if ($elements[$n] =~ /(\[|\()$/);
				$a = 'O' if ($elements[$n] eq '');
				$a = 'E' if ($elements[$n] eq '' && $n == 0);

				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/);
					$c = 'B' if ($elements[$n + 2] =~ /^(\)|\]|;)/);
					$c = 'O' if ($elements[$n + 2] eq '');
				} else {
					$c = 'E';
				}

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

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

				my $ptr = (" " x $off) . "^";
				my $hereptr = "$hereline$ptr\n";

				##print "<$s1:$op:$s2> <$elements[$n]:$elements[$n + 1]:$elements[$n + 2]>\n";

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

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

				# -> should have no spaces
				} elsif ($op eq '->') {
					if ($ctx =~ /Wx.|.xW/) {
						ERROR("no spaces around that '$op' $at\n" . $hereptr);
					}

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

				# unary ! and unary ~ are allowed no space on the right
				} elsif ($op eq '!' or $op eq '~') {
					if ($ctx !~ /[WOEB]x./) {
						ERROR("need space before that '$op' $at\n" . $hereptr);
					}
					if ($ctx =~ /.xW/) {
						ERROR("no space after that '$op' $at\n" . $hereptr);
					}

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

				# & 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
				#
				} elsif ($op eq '&' or $op eq '-') {
					if ($ctx !~ /VxV|[EW]x[WE]|[EWB]x[VO]/) {
						ERROR("need space before that '$op' $at\n" . $hereptr);
					}

				# * is the same as & only adding:
				# type:
				# 	(foo *)
				#	(foo **)
				#
				} elsif ($op eq '*') {
					if ($ca !~ /$Type$/ && $cb !~ /(\*$;|$;\*)/ &&
					    $ctx !~ /VxV|[EW]x[WE]|[EWB]x[VO]|OxV|WxB|BxB/) {
						ERROR("need space before that '$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 $op eq '|')
				{
					if ($ctx !~ /VxV|WxW|VxE|WxE/) {
						ERROR("need consistent spacing around '$op' $at\n" .
							$hereptr);
					}

				# All the others need spaces both sides.
				} elsif ($ctx !~ /[EW]x[WE]/) {
					ERROR("need spaces around that '$op' $at\n" . $hereptr);
				}
				$off += length($elements[$n + 1]);
			}
		}

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

#need space before brace following if, while, etc
		if ($line =~ /\(.*\){/ || $line =~ /do{/) {
			ERROR("need a space 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("need a space after that close brace '}'\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);
		}

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

# Check for illegal assignment in if conditional.
		if ($line=~/\bif\s*\(.*[^<>!=]=[^=].*\)/) {
			#next if ($line=~/\".*\Q$op\E.*\"/ or $line=~/\'\Q$op\E\'/);
			ERROR("do not use assignment in if condition\n" . $herecurr);
		}

		# 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) {
			ERROR("else should follow close brace '}'\n" . $hereprev);
		}

#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 ($line=~/\#define.*\\\s$/) {
			WARN("Whitepspace after \\ makes next lines useless\n" . $herecurr);
		}

#warn if <asm/foo.h> is #included and <linux/foo.h> is available (uses RAW line)
		if ($tree && $rawline =~ m{^.\#\s*include\s*\<asm\/(.*)\.h\>}) {
			my $checkfile = "include/linux/$1.h";
			if (-f $checkfile) {
				CHK("Use #include <linux/$1.h> instead of <asm/$1.h>\n" .
					$herecurr);
			}
		}

# if and else should not have general statements after it
		if ($line =~ /^.\s*(?:}\s*)?else\b(.*)/ &&
		    $1 !~ /^\s*(?:\sif|{|\\|$)/) {
			ERROR("trailing statements should be on next line\n" . $herecurr);
		}

# multi-statement macros should be enclosed in a do while loop, grab the
# first statement and ensure its the whole macro if its not enclosed
# in a known goot container
		if (($prevline=~/\#define.*\\/) and
		   !($prevline=~/do\s+{/) and !($prevline=~/\(\{/) and
		   !($line=~/do.*{/) and !($line=~/\(\{/) and
		   !($line=~/^.\s*$Declare\s/)) {
			# Grab the first statement, if that is the entire macro
			# its ok.  This may start either on the #define line
			# or the one below.
			my $ln = $linenr;
			my $cnt = $realcnt;
			my $off = 0;

			# If the macro starts on the define line start
			# grabbing the statement after the identifier
			$prevline =~ m{^(.#\s*define\s*$Ident(?:\([^\)]*\))?\s*)(.*)\\\s*$};
			##print "1<$1> 2<$2>\n";
			if ($2 ne '') {
				$off = length($1);
				$ln--;
				$cnt++;
			}
			my @ctx = ctx_statement($ln, $cnt, $off);
			my $ctx_ln = $ln + $#ctx + 1;
			my $ctx = join("\n", @ctx);

			# Pull in any empty extension lines.
			while ($ctx =~ /\\$/ &&
			       $lines[$ctx_ln - 1] =~ /^.\s*(?:\\)?$/) {
				$ctx .= $lines[$ctx_ln - 1];
				$ctx_ln++;
			}

			if ($ctx =~ /\\$/) {
				if ($ctx =~ /;/) {
					ERROR("Macros with multiple statements should be enclosed in a do - while loop\n" . "$here\n$ctx\n");
				} else {
					ERROR("Macros with complex values should be enclosed in parenthesis\n" . "$here\n$ctx\n");
				}
			}
		}

# check for redundant bracing round if etc
		if ($line =~ /\b(if|while|for|else)\b/) {
			# Locate the end of the opening statement.
			my @control = ctx_statement($linenr, $realcnt, 0);
			my $nr = $linenr + (scalar(@control) - 1);
			my $cnt = $realcnt - (scalar(@control) - 1);

			my $off = $realcnt - $cnt;
			#print "$off: line<$line>end<" . $lines[$nr - 1] . ">\n";

			# If this is is a braced statement group check it
			if ($lines[$nr - 1] =~ /{\s*$/) {
				my ($lvl, @block) = ctx_block_level($nr, $cnt);

				my $stmt = join(' ', @block);
				$stmt =~ s/^[^{]*{//;
				$stmt =~ s/}[^}]*$//;

				#print "block<" . join(' ', @block) . "><" . scalar(@block) . ">\n";
				#print "stmt<$stmt>\n\n";

				# Count the ;'s if there is fewer than two
				# then there can only be one statement,
				# if there is a brace inside we cannot
				# trivially detect if its one statement.
				# Also nested if's often require braces to
				# disambiguate the else binding so shhh there.
				my @semi = ($stmt =~ /;/g);
				##print "semi<" . scalar(@semi) . ">\n";
				if ($lvl == 0 && scalar(@semi) < 2 &&
				    $stmt !~ /{/ && $stmt !~ /\bif\b/) {
				    	my $herectx = "$here\n" . join("\n", @control, @block[1 .. $#block]) . "\n";
				    	shift(@block);
					ERROR("braces {} are not necessary for single statement blocks\n" . $herectx);
				}
			}
		}

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

# don't use deprecated functions
		for my $func (@dep_functions) {
			if ($line =~ /\b$func\b/) {
				ERROR("Don't use $func(): see Documentation/feature-removal-schedule.txt\n" . $herecurr);
			}
		}

# no volatiles please
		if ($line =~ /\bvolatile\b/ && $line !~ /\basm\s+volatile\b/) {
			WARN("Use of volatile is usually wrong: see Documentation/volatile-considered-harmful.txt\n" . $herecurr);
		}

# warn about #if 0
		if ($line =~ /^.#\s*if\s+0\b/) {
			CHK("if this code is redundant consider removing it\n" .
				$herecurr);
		}

# check for needless kfree() checks
		if ($prevline =~ /\bif\s*\(([^\)]*)\)/) {
			my $expr = $1;
			if ($line =~ /\bkfree\(\Q$expr\E\);/) {
				WARN("kfree(NULL) is safe this check is probabally not required\n" . $hereprev);
			}
		}

# warn about #ifdefs in C files
#		if ($line =~ /^.#\s*if(|n)def/ && ($realfile =~ /\.c$/)) {
#			print "#ifdef in C files should be avoided\n";
#			print "$herecurr";
#			$clean = 0;
#		}

# check for spinlock_t definitions without a comment.
		if ($line =~ /^.\s*(struct\s+mutex|spinlock_t)\s+\S+;/) {
			my $which = $1;
			if (!ctx_has_comment($first_line, $linenr)) {
				CHK("$1 definition without comment\n" . $herecurr);
			}
		}
# check for memory barriers without a comment.
		if ($line =~ /\b(mb|rmb|wmb|read_barrier_depends|smp_mb|smp_rmb|smp_wmb|smp_read_barrier_depends)\(/) {
			if (!ctx_has_comment($first_line, $linenr)) {
				CHK("memory barrier without comment\n" . $herecurr);
			}
		}
# check of hardware specific defines
		if ($line =~ m@^.#\s*if.*\b(__i386__|__powerpc64__|__sun__|__s390x__)\b@) {
			CHK("architecture specific defines should be avoided\n" .  $herecurr);
		}

# check the location of the inline attribute, that it is between
# storage class and type.
		if ($line =~ /$Type\s+(?:inline|__always_inline)\b/ ||
		    $line =~ /\b(?:inline|always_inline)\s+$Storage/) {
			ERROR("inline keyword should sit between storage class and type\n" . $herecurr);
		}

# check for new externs in .c files.
		if ($line =~ /^.\s*extern\s/ && ($realfile =~ /\.c$/)) {
			WARN("externs should be avoided in .c files\n" .  $herecurr);
		}

# checks for new __setup's
		if ($rawline =~ /\b__setup\("([^"]*)"/) {
			my $name = $1;

			if (!grep(/$name/, @setup_docs)) {
				CHK("__setup appears un-documented -- check Documentation/kernel-parameters.txt\n" . $herecurr);
			}
		}
	}

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

	if ($clean == 0 && ($chk_patch || $is_patch)) {
		print report_dump();
	}
	if ($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;
}