xref: /linux/scripts/checkpatch.pl (revision 2b8232ce512105e28453f301d1510de8363bccd1)
1#!/usr/bin/perl -w
2# (c) 2001, Dave Jones. <davej@codemonkey.org.uk> (the file handling bit)
3# (c) 2005, Joel Schopp <jschopp@austin.ibm.com> (the ugly bit)
4# (c) 2007, Andy Whitcroft <apw@uk.ibm.com> (new conditions, test suite, etc)
5# Licensed under the terms of the GNU GPL License version 2
6
7use strict;
8
9my $P = $0;
10$P =~ s@.*/@@g;
11
12my $V = '0.09';
13
14use Getopt::Long qw(:config no_auto_abbrev);
15
16my $quiet = 0;
17my $tree = 1;
18my $chk_signoff = 1;
19my $chk_patch = 1;
20my $tst_type = 0;
21GetOptions(
22	'q|quiet'	=> \$quiet,
23	'tree!'		=> \$tree,
24	'signoff!'	=> \$chk_signoff,
25	'patch!'	=> \$chk_patch,
26	'test-type!'	=> \$tst_type,
27) or exit;
28
29my $exit = 0;
30
31if ($#ARGV < 0) {
32	print "usage: $P [options] patchfile\n";
33	print "version: $V\n";
34	print "options: -q           => quiet\n";
35	print "         --no-tree    => run without a kernel tree\n";
36	exit(1);
37}
38
39if ($tree && !top_of_kernel_tree()) {
40	print "Must be run from the top-level dir. of a kernel tree\n";
41	exit(2);
42}
43
44my @dep_includes = ();
45my @dep_functions = ();
46my $removal = 'Documentation/feature-removal-schedule.txt';
47if ($tree && -f $removal) {
48	open(REMOVE, "<$removal") || die "$P: $removal: open failed - $!\n";
49	while (<REMOVE>) {
50		if (/^Check:\s+(.*\S)/) {
51			for my $entry (split(/[, ]+/, $1)) {
52				if ($entry =~ m@include/(.*)@) {
53					push(@dep_includes, $1);
54
55				} elsif ($entry !~ m@/@) {
56					push(@dep_functions, $entry);
57				}
58			}
59		}
60	}
61}
62
63my @rawlines = ();
64while (<>) {
65	chomp;
66	push(@rawlines, $_);
67	if (eof(ARGV)) {
68		if (!process($ARGV, @rawlines)) {
69			$exit = 1;
70		}
71		@rawlines = ();
72	}
73}
74
75exit($exit);
76
77sub top_of_kernel_tree {
78	if ((-f "COPYING") && (-f "CREDITS") && (-f "Kbuild") &&
79	    (-f "MAINTAINERS") && (-f "Makefile") && (-f "README") &&
80	    (-d "Documentation") && (-d "arch") && (-d "include") &&
81	    (-d "drivers") && (-d "fs") && (-d "init") && (-d "ipc") &&
82	    (-d "kernel") && (-d "lib") && (-d "scripts")) {
83		return 1;
84	}
85	return 0;
86}
87
88sub expand_tabs {
89	my ($str) = @_;
90
91	my $res = '';
92	my $n = 0;
93	for my $c (split(//, $str)) {
94		if ($c eq "\t") {
95			$res .= ' ';
96			$n++;
97			for (; ($n % 8) != 0; $n++) {
98				$res .= ' ';
99			}
100			next;
101		}
102		$res .= $c;
103		$n++;
104	}
105
106	return $res;
107}
108
109sub line_stats {
110	my ($line) = @_;
111
112	# Drop the diff line leader and expand tabs
113	$line =~ s/^.//;
114	$line = expand_tabs($line);
115
116	# Pick the indent from the front of the line.
117	my ($white) = ($line =~ /^(\s*)/);
118
119	return (length($line), length($white));
120}
121
122sub sanitise_line {
123	my ($line) = @_;
124
125	my $res = '';
126	my $l = '';
127
128	my $quote = '';
129
130	foreach my $c (split(//, $line)) {
131		if ($l ne "\\" && ($c eq "'" || $c eq '"')) {
132			if ($quote eq '') {
133				$quote = $c;
134				$res .= $c;
135				$l = $c;
136				next;
137			} elsif ($quote eq $c) {
138				$quote = '';
139			}
140		}
141		if ($quote && $c ne "\t") {
142			$res .= "X";
143		} else {
144			$res .= $c;
145		}
146
147		$l = $c;
148	}
149
150	return $res;
151}
152
153sub ctx_block_get {
154	my ($linenr, $remain, $outer, $open, $close, $off) = @_;
155	my $line;
156	my $start = $linenr - 1;
157	my $blk = '';
158	my @o;
159	my @c;
160	my @res = ();
161
162	my $level = 0;
163	for ($line = $start; $remain > 0; $line++) {
164		next if ($rawlines[$line] =~ /^-/);
165		$remain--;
166
167		$blk .= $rawlines[$line];
168		foreach my $c (split(//, $rawlines[$line])) {
169			##print "C<$c>L<$level><$open$close>O<$off>\n";
170			if ($off > 0) {
171				$off--;
172				next;
173			}
174
175			if ($c eq $close && $level > 0) {
176				$level--;
177				last if ($level == 0);
178			} elsif ($c eq $open) {
179				$level++;
180			}
181		}
182
183		if (!$outer || $level <= 1) {
184			push(@res, $rawlines[$line]);
185		}
186
187		last if ($level == 0);
188	}
189
190	return ($level, @res);
191}
192sub ctx_block_outer {
193	my ($linenr, $remain) = @_;
194
195	my ($level, @r) = ctx_block_get($linenr, $remain, 1, '{', '}', 0);
196	return @r;
197}
198sub ctx_block {
199	my ($linenr, $remain) = @_;
200
201	my ($level, @r) = ctx_block_get($linenr, $remain, 0, '{', '}', 0);
202	return @r;
203}
204sub ctx_statement {
205	my ($linenr, $remain, $off) = @_;
206
207	my ($level, @r) = ctx_block_get($linenr, $remain, 0, '(', ')', $off);
208	return @r;
209}
210sub ctx_block_level {
211	my ($linenr, $remain) = @_;
212
213	return ctx_block_get($linenr, $remain, 0, '{', '}', 0);
214}
215
216sub ctx_locate_comment {
217	my ($first_line, $end_line) = @_;
218
219	# Catch a comment on the end of the line itself.
220	my ($current_comment) = ($rawlines[$end_line - 1] =~ m@.*(/\*.*\*/)\s*$@);
221	return $current_comment if (defined $current_comment);
222
223	# Look through the context and try and figure out if there is a
224	# comment.
225	my $in_comment = 0;
226	$current_comment = '';
227	for (my $linenr = $first_line; $linenr < $end_line; $linenr++) {
228		my $line = $rawlines[$linenr - 1];
229		#warn "           $line\n";
230		if ($linenr == $first_line and $line =~ m@^.\s*\*@) {
231			$in_comment = 1;
232		}
233		if ($line =~ m@/\*@) {
234			$in_comment = 1;
235		}
236		if (!$in_comment && $current_comment ne '') {
237			$current_comment = '';
238		}
239		$current_comment .= $line . "\n" if ($in_comment);
240		if ($line =~ m@\*/@) {
241			$in_comment = 0;
242		}
243	}
244
245	chomp($current_comment);
246	return($current_comment);
247}
248sub ctx_has_comment {
249	my ($first_line, $end_line) = @_;
250	my $cmt = ctx_locate_comment($first_line, $end_line);
251
252	##print "LINE: $rawlines[$end_line - 1 ]\n";
253	##print "CMMT: $cmt\n";
254
255	return ($cmt ne '');
256}
257
258sub cat_vet {
259	my ($vet) = @_;
260
261	$vet =~ s/\t/^I/;
262	$vet =~ s/$/\$/;
263
264	return $vet;
265}
266
267my @report = ();
268sub report {
269	push(@report, $_[0]);
270}
271sub report_dump {
272	@report;
273}
274sub ERROR {
275	report("ERROR: $_[0]\n");
276	our $clean = 0;
277}
278sub WARN {
279	report("WARNING: $_[0]\n");
280	our $clean = 0;
281}
282sub CHK {
283	report("CHECK: $_[0]\n");
284	our $clean = 0;
285}
286
287sub process {
288	my $filename = shift;
289	my @lines = @_;
290
291	my $linenr=0;
292	my $prevline="";
293	my $stashline="";
294
295	my $length;
296	my $indent;
297	my $previndent=0;
298	my $stashindent=0;
299
300	our $clean = 1;
301	my $signoff = 0;
302	my $is_patch = 0;
303
304	# Trace the real file/line as we go.
305	my $realfile = '';
306	my $realline = 0;
307	my $realcnt = 0;
308	my $here = '';
309	my $in_comment = 0;
310	my $first_line = 0;
311
312	my $Ident	= qr{[A-Za-z\d_]+};
313	my $Storage	= qr{extern|static};
314	my $Sparse	= qr{__user|__kernel|__force|__iomem|__must_check|__init_refok};
315	my $NonptrType	= qr{
316				\b
317				(?:const\s+)?
318				(?:unsigned\s+)?
319				(?:
320					void|
321					char|
322					short|
323					int|
324					long|
325					unsigned|
326					float|
327					double|
328					bool|
329					long\s+int|
330					long\s+long|
331					long\s+long\s+int|
332					u8|u16|u32|u64|
333					s8|s16|s32|s64|
334					struct\s+$Ident|
335					union\s+$Ident|
336					enum\s+$Ident|
337					${Ident}_t
338				)
339				(?:\s+$Sparse)*
340				\b
341			  }x;
342	my $Type	= qr{
343				\b$NonptrType\b
344				(?:\s*\*+\s*const|\s*\*+|(?:\s*\[\s*\])+)?
345				(?:\s+$Sparse)*
346			  }x;
347	my $Declare	= qr{(?:$Storage\s+)?$Type};
348	my $Attribute	= qr{const|__read_mostly|__init|__initdata|__meminit};
349
350	my $Member	= qr{->$Ident|\.$Ident|\[[^]]*\]};
351	my $Lval	= qr{$Ident(?:$Member)*};
352
353	# Pre-scan the patch looking for any __setup documentation.
354	my @setup_docs = ();
355	my $setup_docs = 0;
356	foreach my $line (@lines) {
357		if ($line=~/^\+\+\+\s+(\S+)/) {
358			$setup_docs = 0;
359			if ($1 =~ m@Documentation/kernel-parameters.txt$@) {
360				$setup_docs = 1;
361			}
362			next;
363		}
364
365		if ($setup_docs && $line =~ /^\+/) {
366			push(@setup_docs, $line);
367		}
368	}
369
370	foreach my $line (@lines) {
371		$linenr++;
372
373		my $rawline = $line;
374
375#extract the filename as it passes
376		if ($line=~/^\+\+\+\s+(\S+)/) {
377			$realfile=$1;
378			$realfile =~ s@^[^/]*/@@;
379			$in_comment = 0;
380			next;
381		}
382#extract the line range in the file after the patch is applied
383		if ($line=~/^\@\@ -\d+,\d+ \+(\d+)(,(\d+))? \@\@/) {
384			$is_patch = 1;
385			$first_line = $linenr + 1;
386			$in_comment = 0;
387			$realline=$1-1;
388			if (defined $2) {
389				$realcnt=$3+1;
390			} else {
391				$realcnt=1+1;
392			}
393			next;
394		}
395
396# track the line number as we move through the hunk, note that
397# new versions of GNU diff omit the leading space on completely
398# blank context lines so we need to count that too.
399		if ($line =~ /^( |\+|$)/) {
400			$realline++;
401			$realcnt-- if ($realcnt != 0);
402
403			# track any sort of multi-line comment.  Obviously if
404			# the added text or context do not include the whole
405			# comment we will not see it. Such is life.
406			#
407			# Guestimate if this is a continuing comment.  If this
408			# is the start of a diff block and this line starts
409			# ' *' then it is very likely a comment.
410			if ($linenr == $first_line and $line =~ m@^.\s*\*@) {
411				$in_comment = 1;
412			}
413			if ($line =~ m@/\*@) {
414				$in_comment = 1;
415			}
416			if ($line =~ m@\*/@) {
417				$in_comment = 0;
418			}
419
420			# Measure the line length and indent.
421			($length, $indent) = line_stats($line);
422
423			# Track the previous line.
424			($prevline, $stashline) = ($stashline, $line);
425			($previndent, $stashindent) = ($stashindent, $indent);
426		} elsif ($realcnt == 1) {
427			$realcnt--;
428		}
429
430#make up the handle for any error we report on this line
431		$here = "#$linenr: ";
432		$here .= "FILE: $realfile:$realline:" if ($realcnt != 0);
433
434		my $hereline = "$here\n$line\n";
435		my $herecurr = "$here\n$line\n";
436		my $hereprev = "$here\n$prevline\n$line\n";
437
438#check the patch for a signoff:
439		if ($line =~ /^\s*signed-off-by:/i) {
440			# This is a signoff, if ugly, so do not double report.
441			$signoff++;
442			if (!($line =~ /^\s*Signed-off-by:/)) {
443				WARN("Signed-off-by: is the preferred form\n" .
444					$herecurr);
445			}
446			if ($line =~ /^\s*signed-off-by:\S/i) {
447				WARN("need space after Signed-off-by:\n" .
448					$herecurr);
449			}
450		}
451
452# Check for wrappage within a valid hunk of the file
453		if ($realcnt != 0 && $line !~ m{^(?:\+|-| |$)}) {
454			ERROR("patch seems to be corrupt (line wrapped?)\n" .
455				$herecurr);
456		}
457
458# UTF-8 regex found at http://www.w3.org/International/questions/qa-forms-utf-8.en.php
459		if (($realfile =~ /^$/ || $line =~ /^\+/) &&
460		     !($line =~ m/^(
461				[\x09\x0A\x0D\x20-\x7E]              # ASCII
462				| [\xC2-\xDF][\x80-\xBF]             # non-overlong 2-byte
463				|  \xE0[\xA0-\xBF][\x80-\xBF]        # excluding overlongs
464				| [\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}  # straight 3-byte
465				|  \xED[\x80-\x9F][\x80-\xBF]        # excluding surrogates
466				|  \xF0[\x90-\xBF][\x80-\xBF]{2}     # planes 1-3
467				| [\xF1-\xF3][\x80-\xBF]{3}          # planes 4-15
468				|  \xF4[\x80-\x8F][\x80-\xBF]{2}     # plane 16
469				)*$/x )) {
470			ERROR("Invalid UTF-8\n" . $herecurr);
471		}
472
473#ignore lines being removed
474		if ($line=~/^-/) {next;}
475
476# check we are in a valid source file if not then ignore this hunk
477		next if ($realfile !~ /\.(h|c|s|S|pl|sh)$/);
478
479#trailing whitespace
480		if ($line =~ /^\+.*\S\s+$/ || $line =~ /^\+\s+$/) {
481			my $herevet = "$here\n" . cat_vet($line) . "\n";
482			ERROR("trailing whitespace\n" . $herevet);
483		}
484#80 column limit
485		if ($line =~ /^\+/ && !($prevline=~/\/\*\*/) && $length > 80) {
486			WARN("line over 80 characters\n" . $herecurr);
487		}
488
489# check we are in a valid source file *.[hc] if not then ignore this hunk
490		next if ($realfile !~ /\.[hc]$/);
491
492# at the beginning of a line any tabs must come first and anything
493# more than 8 must use tabs.
494		if ($line=~/^\+\s* \t\s*\S/ or $line=~/^\+\s*        \s*/) {
495			my $herevet = "$here\n" . cat_vet($line) . "\n";
496			ERROR("use tabs not spaces\n" . $herevet);
497		}
498
499# Remove comments from the line before processing.
500		my $comment_edge = ($line =~ s@/\*.*\*/@@g) +
501				   ($line =~ s@/\*.*@@) +
502				   ($line =~ s@^(.).*\*/@$1@);
503
504# The rest of our checks refer specifically to C style
505# only apply those _outside_ comments.  Only skip
506# lines in the middle of comments.
507		next if (!$comment_edge && $in_comment);
508
509# Standardise the strings and chars within the input to simplify matching.
510		$line = sanitise_line($line);
511
512#
513# Checks which may be anchored in the context.
514#
515
516# Check for switch () and associated case and default
517# statements should be at the same indent.
518		if ($line=~/\bswitch\s*\(.*\)/) {
519			my $err = '';
520			my $sep = '';
521			my @ctx = ctx_block_outer($linenr, $realcnt);
522			shift(@ctx);
523			for my $ctx (@ctx) {
524				my ($clen, $cindent) = line_stats($ctx);
525				if ($ctx =~ /^\+\s*(case\s+|default:)/ &&
526							$indent != $cindent) {
527					$err .= "$sep$ctx\n";
528					$sep = '';
529				} else {
530					$sep = "[...]\n";
531				}
532			}
533			if ($err ne '') {
534				ERROR("switch and case should be at the same indent\n$hereline\n$err\n");
535			}
536		}
537
538# if/while/etc brace do not go on next line, unless defining a do while loop,
539# or if that brace on the next line is for something else
540		if ($line =~ /\b(?:(if|while|for|switch)\s*\(|do\b|else\b)/ && $line !~ /^.#/) {
541			my @ctx = ctx_statement($linenr, $realcnt, 0);
542			my $ctx_ln = $linenr + $#ctx + 1;
543			my $ctx_cnt = $realcnt - $#ctx - 1;
544			my $ctx = join("\n", @ctx);
545
546			while ($ctx_cnt > 0 && $lines[$ctx_ln - 1] =~ /^-/) {
547				$ctx_ln++;
548				$ctx_cnt--;
549			}
550			##warn "line<$line>\nctx<$ctx>\nnext<$lines[$ctx_ln - 1]>";
551
552			if ($ctx !~ /{\s*/ && $ctx_cnt > 0 && $lines[$ctx_ln - 1] =~ /^\+\s*{/) {
553				ERROR("That open brace { should be on the previous line\n" .
554					"$here\n$ctx\n$lines[$ctx_ln - 1]");
555			}
556		}
557
558#ignore lines not being added
559		if ($line=~/^[^\+]/) {next;}
560
561# TEST: allow direct testing of the type matcher.
562		if ($tst_type && $line =~ /^.$Declare$/) {
563			ERROR("TEST: is type $Declare\n" . $herecurr);
564			next;
565		}
566
567# check for initialisation to aggregates open brace on the next line
568		if ($prevline =~ /$Declare\s*$Ident\s*=\s*$/ &&
569		    $line =~ /^.\s*{/) {
570			ERROR("That open brace { should be on the previous line\n" . $hereprev);
571		}
572
573#
574# Checks which are anchored on the added line.
575#
576
577# check for malformed paths in #include statements (uses RAW line)
578		if ($rawline =~ m{^.#\s*include\s+[<"](.*)[">]}) {
579			my $path = $1;
580			if ($path =~ m{//}) {
581				ERROR("malformed #include filename\n" .
582					$herecurr);
583			}
584			# Sanitise this special form of string.
585			$path = 'X' x length($path);
586			$line =~ s{\<.*\>}{<$path>};
587		}
588
589# no C99 // comments
590		if ($line =~ m{//}) {
591			ERROR("do not use C99 // comments\n" . $herecurr);
592		}
593		# Remove C99 comments.
594		$line =~ s@//.*@@;
595
596#EXPORT_SYMBOL should immediately follow its function closing }.
597		if (($line =~ /EXPORT_SYMBOL.*\((.*)\)/) ||
598		    ($line =~ /EXPORT_UNUSED_SYMBOL.*\((.*)\)/)) {
599			my $name = $1;
600			if (($prevline !~ /^}/) &&
601			   ($prevline !~ /^\+}/) &&
602			   ($prevline !~ /^ }/) &&
603			   ($prevline !~ /\b\Q$name\E(?:\s+$Attribute)?\s*(?:;|=)/)) {
604				WARN("EXPORT_SYMBOL(foo); should immediately follow its function/variable\n" . $herecurr);
605			}
606		}
607
608# check for external initialisers.
609		if ($line =~ /^.$Type\s*$Ident\s*=\s*(0|NULL);/) {
610			ERROR("do not initialise externals to 0 or NULL\n" .
611				$herecurr);
612		}
613# check for static initialisers.
614		if ($line =~ /\s*static\s.*=\s*(0|NULL);/) {
615			ERROR("do not initialise statics to 0 or NULL\n" .
616				$herecurr);
617		}
618
619# check for new typedefs, only function parameters and sparse annotations
620# make sense.
621		if ($line =~ /\btypedef\s/ &&
622		    $line !~ /\btypedef\s+$Type\s+\(\s*\*$Ident\s*\)\s*\(/ &&
623		    $line !~ /\b__bitwise(?:__|)\b/) {
624			WARN("do not add new typedefs\n" . $herecurr);
625		}
626
627# * goes on variable not on type
628		if ($line =~ m{\($NonptrType(\*+)(?:\s+const)?\)}) {
629			ERROR("\"(foo$1)\" should be \"(foo $1)\"\n" .
630				$herecurr);
631
632		} elsif ($line =~ m{\($NonptrType\s+(\*+)(?!\s+const)\s+\)}) {
633			ERROR("\"(foo $1 )\" should be \"(foo $1)\"\n" .
634				$herecurr);
635
636		} elsif ($line =~ m{$NonptrType(\*+)(?:\s+$Attribute)?\s+[A-Za-z\d_]+}) {
637			ERROR("\"foo$1 bar\" should be \"foo $1bar\"\n" .
638				$herecurr);
639
640		} elsif ($line =~ m{$NonptrType\s+(\*+)(?!\s+$Attribute)\s+[A-Za-z\d_]+}) {
641			ERROR("\"foo $1 bar\" should be \"foo $1bar\"\n" .
642				$herecurr);
643		}
644
645# # no BUG() or BUG_ON()
646# 		if ($line =~ /\b(BUG|BUG_ON)\b/) {
647# 			print "Try to use WARN_ON & Recovery code rather than BUG() or BUG_ON()\n";
648# 			print "$herecurr";
649# 			$clean = 0;
650# 		}
651
652# printk should use KERN_* levels.  Note that follow on printk's on the
653# same line do not need a level, so we use the current block context
654# to try and find and validate the current printk.  In summary the current
655# printk includes all preceeding printk's which have no newline on the end.
656# we assume the first bad printk is the one to report.
657		if ($line =~ /\bprintk\((?!KERN_)\s*"/) {
658			my $ok = 0;
659			for (my $ln = $linenr - 1; $ln >= $first_line; $ln--) {
660				#print "CHECK<$lines[$ln - 1]\n";
661				# we have a preceeding printk if it ends
662				# with "\n" ignore it, else it is to blame
663				if ($lines[$ln - 1] =~ m{\bprintk\(}) {
664					if ($rawlines[$ln - 1] !~ m{\\n"}) {
665						$ok = 1;
666					}
667					last;
668				}
669			}
670			if ($ok == 0) {
671				WARN("printk() should include KERN_ facility level\n" . $herecurr);
672			}
673		}
674
675# function brace can't be on same line, except for #defines of do while,
676# or if closed on same line
677		if (($line=~/$Type\s*[A-Za-z\d_]+\(.*\).* {/) and
678		    !($line=~/\#define.*do\s{/) and !($line=~/}/)) {
679			ERROR("open brace '{' following function declarations go on the next line\n" . $herecurr);
680		}
681
682# check for spaces between functions and their parentheses.
683		if ($line =~ /($Ident)\s+\(/ &&
684		    $1 !~ /^(?:if|for|while|switch|return|volatile|__volatile__|__attribute__|format|__extension__|Copyright)$/ &&
685		    $line !~ /$Type\s+\(/ && $line !~ /^.\#\s*define\b/) {
686			WARN("no space between function name and open parenthesis '('\n" . $herecurr);
687		}
688# Check operator spacing.
689		# Note we expand the line with the leading + as the real
690		# line will be displayed with the leading + and the tabs
691		# will therefore also expand that way.
692		my $opline = $line;
693		$opline = expand_tabs($opline);
694		$opline =~ s/^./ /;
695		if (!($line=~/\#\s*include/)) {
696			my @elements = split(/(<<=|>>=|<=|>=|==|!=|\+=|-=|\*=|\/=|%=|\^=|\|=|&=|=>|->|<<|>>|<|>|=|!|~|&&|\|\||,|\^|\+\+|--|;|&|\||\+|-|\*|\/\/|\/)/, $opline);
697			my $off = 0;
698			for (my $n = 0; $n < $#elements; $n += 2) {
699				$off += length($elements[$n]);
700
701				my $a = '';
702				$a = 'V' if ($elements[$n] ne '');
703				$a = 'W' if ($elements[$n] =~ /\s$/);
704				$a = 'B' if ($elements[$n] =~ /(\[|\()$/);
705				$a = 'O' if ($elements[$n] eq '');
706				$a = 'E' if ($elements[$n] eq '' && $n == 0);
707
708				my $op = $elements[$n + 1];
709
710				my $c = '';
711				if (defined $elements[$n + 2]) {
712					$c = 'V' if ($elements[$n + 2] ne '');
713					$c = 'W' if ($elements[$n + 2] =~ /^\s/);
714					$c = 'B' if ($elements[$n + 2] =~ /^(\)|\]|;)/);
715					$c = 'O' if ($elements[$n + 2] eq '');
716					$c = 'E' if ($elements[$n + 2] =~ /\s*\\$/);
717				} else {
718					$c = 'E';
719				}
720
721				# Pick up the preceeding and succeeding characters.
722				my $ca = substr($opline, 0, $off);
723				my $cc = '';
724				if (length($opline) >= ($off + length($elements[$n + 1]))) {
725					$cc = substr($opline, $off + length($elements[$n + 1]));
726				}
727				my $cb = "$ca$;$cc";
728
729				my $ctx = "${a}x${c}";
730
731				my $at = "(ctx:$ctx)";
732
733				my $ptr = (" " x $off) . "^";
734				my $hereptr = "$hereline$ptr\n";
735
736				##print "<$s1:$op:$s2> <$elements[$n]:$elements[$n + 1]:$elements[$n + 2]>\n";
737
738				# ; should have either the end of line or a space or \ after it
739				if ($op eq ';') {
740					if ($ctx !~ /.x[WEB]/ && $cc !~ /^\\/ &&
741					    $cc !~ /^;/) {
742						ERROR("need space after that '$op' $at\n" . $hereptr);
743					}
744
745				# // is a comment
746				} elsif ($op eq '//') {
747
748				# -> should have no spaces
749				} elsif ($op eq '->') {
750					if ($ctx =~ /Wx.|.xW/) {
751						ERROR("no spaces around that '$op' $at\n" . $hereptr);
752					}
753
754				# , must have a space on the right.
755				} elsif ($op eq ',') {
756					if ($ctx !~ /.xW|.xE/ && $cc !~ /^}/) {
757						ERROR("need space after that '$op' $at\n" . $hereptr);
758					}
759
760				# unary ! and unary ~ are allowed no space on the right
761				} elsif ($op eq '!' or $op eq '~') {
762					if ($ctx !~ /[WOEB]x./) {
763						ERROR("need space before that '$op' $at\n" . $hereptr);
764					}
765					if ($ctx =~ /.xW/) {
766						ERROR("no space after that '$op' $at\n" . $hereptr);
767					}
768
769				# unary ++ and unary -- are allowed no space on one side.
770				} elsif ($op eq '++' or $op eq '--') {
771					if ($ctx !~ /[WOB]x[^W]/ && $ctx !~ /[^W]x[WOBE]/) {
772						ERROR("need space one side of that '$op' $at\n" . $hereptr);
773					}
774					if ($ctx =~ /Wx./ && $cc =~ /^;/) {
775						ERROR("no space before that '$op' $at\n" . $hereptr);
776					}
777
778				# & is both unary and binary
779				# unary:
780				# 	a &b
781				# binary (consistent spacing):
782				#	a&b		OK
783				#	a & b		OK
784				#
785				# boiling down to: if there is a space on the right then there
786				# should be one on the left.
787				#
788				# - is the same
789				#
790				} elsif ($op eq '&' or $op eq '-') {
791					if ($ctx !~ /VxV|[EW]x[WE]|[EWB]x[VO]/) {
792						ERROR("need space before that '$op' $at\n" . $hereptr);
793					}
794
795				# * is the same as & only adding:
796				# type:
797				# 	(foo *)
798				#	(foo **)
799				#
800				} elsif ($op eq '*') {
801					if ($ca !~ /$Type$/ && $cb !~ /(\*$;|$;\*)/ &&
802					    $ctx !~ /VxV|[EW]x[WE]|[EWB]x[VO]|OxV|WxB|BxB/) {
803						ERROR("need space before that '$op' $at\n" . $hereptr);
804					}
805
806				# << and >> may either have or not have spaces both sides
807				} elsif ($op eq '<<' or $op eq '>>' or $op eq '+' or $op eq '/' or
808					 $op eq '^' or $op eq '|')
809				{
810					if ($ctx !~ /VxV|WxW|VxE|WxE/) {
811						ERROR("need consistent spacing around '$op' $at\n" .
812							$hereptr);
813					}
814
815				# All the others need spaces both sides.
816				} elsif ($ctx !~ /[EW]x[WE]/) {
817					# Ignore email addresses <foo@bar>
818					if (!($op eq '<' && $cb =~ /$;\S+\@\S+>/) &&
819					    !($op eq '>' && $cb =~ /<\S+\@\S+$;/)) {
820						ERROR("need spaces around that '$op' $at\n" . $hereptr);
821					}
822				}
823				$off += length($elements[$n + 1]);
824			}
825		}
826
827# check for multiple assignments
828		if ($line =~ /^.\s*$Lval\s*=\s*$Lval\s*=(?!=)/) {
829			WARN("multiple assignments should be avoided\n" . $herecurr);
830		}
831
832## # check for multiple declarations, allowing for a function declaration
833## # continuation.
834## 		if ($line =~ /^.\s*$Type\s+$Ident(?:\s*=[^,{]*)?\s*,\s*$Ident.*/ &&
835## 		    $line !~ /^.\s*$Type\s+$Ident(?:\s*=[^,{]*)?\s*,\s*$Type\s*$Ident.*/) {
836##
837## 			# Remove any bracketed sections to ensure we do not
838## 			# falsly report the parameters of functions.
839## 			my $ln = $line;
840## 			while ($ln =~ s/\([^\(\)]*\)//g) {
841## 			}
842## 			if ($ln =~ /,/) {
843## 				WARN("declaring multiple variables together should be avoided\n" . $herecurr);
844## 			}
845## 		}
846
847#need space before brace following if, while, etc
848		if (($line =~ /\(.*\){/ && $line !~ /\($Type\){/) ||
849		    $line =~ /do{/) {
850			ERROR("need a space before the open brace '{'\n" . $herecurr);
851		}
852
853# closing brace should have a space following it when it has anything
854# on the line
855		if ($line =~ /}(?!(?:,|;|\)))\S/) {
856			ERROR("need a space after that close brace '}'\n" . $herecurr);
857		}
858
859# check spacing on square brackets
860		if ($line =~ /\[\s/ && $line !~ /\[\s*$/) {
861			ERROR("no space after that open square bracket '['\n" . $herecurr);
862		}
863		if ($line =~ /\s\]/) {
864			ERROR("no space before that close square bracket ']'\n" . $herecurr);
865		}
866
867# check spacing on paretheses
868		if ($line =~ /\(\s/ && $line !~ /\(\s*$/) {
869			ERROR("no space after that open parenthesis '('\n" . $herecurr);
870		}
871		if ($line =~ /\s\)/) {
872			ERROR("no space before that close parenthesis ')'\n" . $herecurr);
873		}
874
875#goto labels aren't indented, allow a single space however
876		if ($line=~/^.\s+[A-Za-z\d_]+:(?![0-9]+)/ and
877		   !($line=~/^. [A-Za-z\d_]+:/) and !($line=~/^.\s+default:/)) {
878			WARN("labels should not be indented\n" . $herecurr);
879		}
880
881# Need a space before open parenthesis after if, while etc
882		if ($line=~/\b(if|while|for|switch)\(/) {
883			ERROR("need a space before the open parenthesis '('\n" . $herecurr);
884		}
885
886# Check for illegal assignment in if conditional.
887		if ($line=~/\bif\s*\(.*[^<>!=]=[^=].*\)/) {
888			#next if ($line=~/\".*\Q$op\E.*\"/ or $line=~/\'\Q$op\E\'/);
889			ERROR("do not use assignment in if condition\n" . $herecurr);
890		}
891
892		# Check for }<nl>else {, these must be at the same
893		# indent level to be relevant to each other.
894		if ($prevline=~/}\s*$/ and $line=~/^.\s*else\s*/ and
895						$previndent == $indent) {
896			ERROR("else should follow close brace '}'\n" . $hereprev);
897		}
898
899#studly caps, commented out until figure out how to distinguish between use of existing and adding new
900#		if (($line=~/[\w_][a-z\d]+[A-Z]/) and !($line=~/print/)) {
901#		    print "No studly caps, use _\n";
902#		    print "$herecurr";
903#		    $clean = 0;
904#		}
905
906#no spaces allowed after \ in define
907		if ($line=~/\#define.*\\\s$/) {
908			WARN("Whitepspace after \\ makes next lines useless\n" . $herecurr);
909		}
910
911#warn if <asm/foo.h> is #included and <linux/foo.h> is available (uses RAW line)
912		if ($tree && $rawline =~ m{^.\#\s*include\s*\<asm\/(.*)\.h\>}) {
913			my $checkfile = "include/linux/$1.h";
914			if (-f $checkfile) {
915				CHK("Use #include <linux/$1.h> instead of <asm/$1.h>\n" .
916					$herecurr);
917			}
918		}
919
920# if and else should not have general statements after it
921		if ($line =~ /^.\s*(?:}\s*)?else\b(.*)/ &&
922		    $1 !~ /^\s*(?:\sif|{|\\|$)/) {
923			ERROR("trailing statements should be on next line\n" . $herecurr);
924		}
925
926# multi-statement macros should be enclosed in a do while loop, grab the
927# first statement and ensure its the whole macro if its not enclosed
928# in a known goot container
929		if (($prevline=~/\#define.*\\/) and
930		   !($prevline=~/do\s+{/) and !($prevline=~/\(\{/) and
931		   !($line=~/do.*{/) and !($line=~/\(\{/) and
932		   !($line=~/^.\s*$Declare\s/)) {
933			# Grab the first statement, if that is the entire macro
934			# its ok.  This may start either on the #define line
935			# or the one below.
936			my $ln = $linenr;
937			my $cnt = $realcnt;
938			my $off = 0;
939
940			# If the macro starts on the define line start
941			# grabbing the statement after the identifier
942			$prevline =~ m{^(.#\s*define\s*$Ident(?:\([^\)]*\))?\s*)(.*)\\\s*$};
943			##print "1<$1> 2<$2>\n";
944			if (defined $2 && $2 ne '') {
945				$off = length($1);
946				$ln--;
947				$cnt++;
948			}
949			my @ctx = ctx_statement($ln, $cnt, $off);
950			my $ctx_ln = $ln + $#ctx + 1;
951			my $ctx = join("\n", @ctx);
952
953			# Pull in any empty extension lines.
954			while ($ctx =~ /\\$/ &&
955			       $lines[$ctx_ln - 1] =~ /^.\s*(?:\\)?$/) {
956				$ctx .= $lines[$ctx_ln - 1];
957				$ctx_ln++;
958			}
959
960			if ($ctx =~ /\\$/) {
961				if ($ctx =~ /;/) {
962					ERROR("Macros with multiple statements should be enclosed in a do - while loop\n" . "$here\n$ctx\n");
963				} else {
964					ERROR("Macros with complex values should be enclosed in parenthesis\n" . "$here\n$ctx\n");
965				}
966			}
967		}
968
969# check for redundant bracing round if etc
970		if ($line =~ /\b(if|while|for|else)\b/) {
971			# Locate the end of the opening statement.
972			my @control = ctx_statement($linenr, $realcnt, 0);
973			my $nr = $linenr + (scalar(@control) - 1);
974			my $cnt = $realcnt - (scalar(@control) - 1);
975
976			my $off = $realcnt - $cnt;
977			#print "$off: line<$line>end<" . $lines[$nr - 1] . ">\n";
978
979			# If this is is a braced statement group check it
980			if ($lines[$nr - 1] =~ /{\s*$/) {
981				my ($lvl, @block) = ctx_block_level($nr, $cnt);
982
983				my $stmt = join(' ', @block);
984				$stmt =~ s/(^[^{]*){//;
985				my $before = $1;
986				$stmt =~ s/}([^}]*$)//;
987				my $after = $1;
988
989				#print "block<" . join(' ', @block) . "><" . scalar(@block) . ">\n";
990				#print "stmt<$stmt>\n\n";
991
992				# Count the ;'s if there is fewer than two
993				# then there can only be one statement,
994				# if there is a brace inside we cannot
995				# trivially detect if its one statement.
996				# Also nested if's often require braces to
997				# disambiguate the else binding so shhh there.
998				my @semi = ($stmt =~ /;/g);
999				push(@semi, "/**/") if ($stmt =~ m@/\*@);
1000				##print "semi<" . scalar(@semi) . ">\n";
1001				if ($lvl == 0 && scalar(@semi) < 2 &&
1002				    $stmt !~ /{/ && $stmt !~ /\bif\b/ &&
1003				    $before !~ /}/ && $after !~ /{/) {
1004				    	my $herectx = "$here\n" . join("\n", @control, @block[1 .. $#block]) . "\n";
1005				    	shift(@block);
1006					WARN("braces {} are not necessary for single statement blocks\n" . $herectx);
1007				}
1008			}
1009		}
1010
1011# don't include deprecated include files (uses RAW line)
1012		for my $inc (@dep_includes) {
1013			if ($rawline =~ m@\#\s*include\s*\<$inc>@) {
1014				ERROR("Don't use <$inc>: see Documentation/feature-removal-schedule.txt\n" . $herecurr);
1015			}
1016		}
1017
1018# don't use deprecated functions
1019		for my $func (@dep_functions) {
1020			if ($line =~ /\b$func\b/) {
1021				ERROR("Don't use $func(): see Documentation/feature-removal-schedule.txt\n" . $herecurr);
1022			}
1023		}
1024
1025# no volatiles please
1026		if ($line =~ /\bvolatile\b/ && $line !~ /\basm\s+volatile\b/) {
1027			WARN("Use of volatile is usually wrong: see Documentation/volatile-considered-harmful.txt\n" . $herecurr);
1028		}
1029
1030# warn about #if 0
1031		if ($line =~ /^.#\s*if\s+0\b/) {
1032			CHK("if this code is redundant consider removing it\n" .
1033				$herecurr);
1034		}
1035
1036# check for needless kfree() checks
1037		if ($prevline =~ /\bif\s*\(([^\)]*)\)/) {
1038			my $expr = $1;
1039			if ($line =~ /\bkfree\(\Q$expr\E\);/) {
1040				WARN("kfree(NULL) is safe this check is probabally not required\n" . $hereprev);
1041			}
1042		}
1043
1044# warn about #ifdefs in C files
1045#		if ($line =~ /^.#\s*if(|n)def/ && ($realfile =~ /\.c$/)) {
1046#			print "#ifdef in C files should be avoided\n";
1047#			print "$herecurr";
1048#			$clean = 0;
1049#		}
1050
1051# warn about spacing in #ifdefs
1052		if ($line =~ /^.#\s*(ifdef|ifndef|elif)\s\s+/) {
1053			ERROR("exactly one space required after that #$1\n" . $herecurr);
1054		}
1055
1056# check for spinlock_t definitions without a comment.
1057		if ($line =~ /^.\s*(struct\s+mutex|spinlock_t)\s+\S+;/) {
1058			my $which = $1;
1059			if (!ctx_has_comment($first_line, $linenr)) {
1060				CHK("$1 definition without comment\n" . $herecurr);
1061			}
1062		}
1063# check for memory barriers without a comment.
1064		if ($line =~ /\b(mb|rmb|wmb|read_barrier_depends|smp_mb|smp_rmb|smp_wmb|smp_read_barrier_depends)\(/) {
1065			if (!ctx_has_comment($first_line, $linenr)) {
1066				CHK("memory barrier without comment\n" . $herecurr);
1067			}
1068		}
1069# check of hardware specific defines
1070		if ($line =~ m@^.#\s*if.*\b(__i386__|__powerpc64__|__sun__|__s390x__)\b@ && $realfile !~ m@include/asm-@) {
1071			CHK("architecture specific defines should be avoided\n" .  $herecurr);
1072		}
1073
1074# check the location of the inline attribute, that it is between
1075# storage class and type.
1076		if ($line =~ /$Type\s+(?:inline|__always_inline|noinline)\b/ ||
1077		    $line =~ /\b(?:inline|__always_inline|noinline)\s+$Storage/) {
1078			ERROR("inline keyword should sit between storage class and type\n" . $herecurr);
1079		}
1080
1081# check for new externs in .c files.
1082		if ($line =~ /^.\s*extern\s/ && ($realfile =~ /\.c$/)) {
1083			WARN("externs should be avoided in .c files\n" .  $herecurr);
1084		}
1085
1086# checks for new __setup's
1087		if ($rawline =~ /\b__setup\("([^"]*)"/) {
1088			my $name = $1;
1089
1090			if (!grep(/$name/, @setup_docs)) {
1091				CHK("__setup appears un-documented -- check Documentation/kernel-parameters.txt\n" . $herecurr);
1092			}
1093		}
1094	}
1095
1096	if ($chk_patch && !$is_patch) {
1097		ERROR("Does not appear to be a unified-diff format patch\n");
1098	}
1099	if ($is_patch && $chk_signoff && $signoff == 0) {
1100		ERROR("Missing Signed-off-by: line(s)\n");
1101	}
1102
1103	if ($clean == 0 && ($chk_patch || $is_patch)) {
1104		print report_dump();
1105	}
1106	if ($clean == 1 && $quiet == 0) {
1107		print "Your patch has no obvious style problems and is ready for submission.\n"
1108	}
1109	if ($clean == 0 && $quiet == 0) {
1110		print "Your patch has style problems, please review.  If any of these errors\n";
1111		print "are false positives report them to the maintainer, see\n";
1112		print "CHECKPATCH in MAINTAINERS.\n";
1113	}
1114	return $clean;
1115}
1116