summaryrefslogtreecommitdiffstats
path: root/scripts/checkpatch.pl
blob: aea90d30d2292dc3427de4958a2e3b32ef374f85 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
#!/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 = '0.04';

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

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

my $exit = 0;

if ($#ARGV < 0) {
	print "usage: $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 (/^Files:\s+(.*\S)/) {
			for my $file (split(/[, ]+/, $1)) {
				if ($file =~ m@include/(.*)@) {
					push(@dep_includes, $1);
				}
			}

		} elsif (/^Funcs:\s+(.*\S)/) {
			for my $func (split(/[, ]+/, $1)) {
				push(@dep_functions, $func);
			}
		}
	}
}

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) = @_;
	my $line;
	my $start = $linenr - 1;
	my $blk = '';
	my @o;
	my @c;
	my @res = ();

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

		$blk .= $rawlines[$line];

		@o = ($blk =~ /\{/g);
		@c = ($blk =~ /\}/g);

		if (!$outer || (scalar(@o) - scalar(@c)) == 1) {
			push(@res, $rawlines[$line]);
		}

		last if (scalar(@o) == scalar(@c));
	}

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

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

	return ctx_block_get($linenr, $remain, 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;
}

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

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

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

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

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

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

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

			# 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);
		}
		$realcnt-- if ($realcnt != 0);

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

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

		} elsif ($line =~ /^\s*signed-off-by:/i) {
			# This is a signoff, if ugly, so do not double report.
			$signoff++;
			if (!($line =~ /^\s*Signed-off-by:/)) {
				print "use Signed-off-by:\n";
				print "$herecurr";
				$clean = 0;
			}
			if ($line =~ /^\s*signed-off-by:\S/i) {
				print "need space after Signed-off-by:\n";
				print "$herecurr";
				$clean = 0;
			}
		}

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

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

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

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

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

		# Remove comments from the line before processing.
		$line =~ s@/\*.*\*/@@g;
		$line =~ s@/\*.*@@;
		$line =~ 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 '') {
				print "switch and case should be at the same indent\n";
				print "$here\n$line\n$err\n";
				$clean = 0;
			}
		}

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

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

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

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

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

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

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

# * goes on variable not on type
		my $type = '(?:char|short|int|long|unsigned|float|double|' .
			   'struct\s+[A-Za-z\d_]+|' .
			   'union\s+[A-Za-z\d_]+)';

		if ($line =~ m{[A-Za-z\d_]+(\*+) [A-Za-z\d_]+}) {
			print "\"foo$1 bar\" should be \"foo $1bar\"\n";
			print "$herecurr";
			$clean = 0;
		}
		if ($line =~ m{$type (\*) [A-Za-z\d_]+} ||
		    $line =~ m{[A-Za-z\d_]+ (\*\*+) [A-Za-z\d_]+}) {
			print "\"foo $1 bar\" should be \"foo $1bar\"\n";
			print "$herecurr";
			$clean = 0;
		}
		if ($line =~ m{\([A-Za-z\d_\s]+[A-Za-z\d_](\*+)\)}) {
			print "\"(foo$1)\" should be \"(foo $1)\"\n";
			print "$herecurr";
			$clean = 0;
		}
		if ($line =~ m{\([A-Za-z\d_\s]+[A-Za-z\d_]\s+(\*+)\s+\)}) {
			print "\"(foo $1 )\" should be \"(foo $1)\"\n";
			print "$herecurr";
			$clean = 0;
		}

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

# printk should use KERN_* levels.  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_)/) {
			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) {
				print "printk() should include KERN_ facility level\n";
				print "$herecurr";
				$clean = 0;
			}
		}

#function brace can't be on same line, except for #defines of do while, or if closed on same line
		if (($line=~/[A-Za-z\d_]+\**\s+\**[A-Za-z\d_]+\(.*\).* {/) and
		    !($line=~/\#define.*do\s{/) and !($line=~/}/)) {
			print "braces following function declarations go on the next line\n";
			print "$herecurr";
			$clean = 0;
		}
		# 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/)) {
			# Check operator spacing.
			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, $off - 1, 1);
				my $cc = '';
				if (length($opline) > ($off + length($elements[$n]))) {
					$cc = substr($opline, $off + 1 + length($elements[$n]), 1);
				}

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

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

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

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

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

				# -> should have no spaces
				} elsif ($op eq '->') {
					if ($ctx =~ /Wx.|.xW/) {
						print "no spaces around that '$op' $at\n";
						print "$hereptr";
						$clean = 0;
					}

				# , must have a space on the right.
				} elsif ($op eq ',') {
					if ($ctx !~ /.xW|.xE/) {
						print "need space after that '$op' $at\n";
						print "$hereptr";
						$clean = 0;
					}

				# unary ! and unary ~ are allowed no space on the right
				} elsif ($op eq '!' or $op eq '~') {
					if ($ctx !~ /[WOEB]x./) {
						print "need space before that '$op' $at\n";
						print "$hereptr";
						$clean = 0;
					}
					if ($ctx =~ /.xW/) {
						print "no space after that '$op' $at\n";
						print "$hereptr";
						$clean = 0;
					}

				# unary ++ and unary -- are allowed no space on one side.
				} elsif ($op eq '++' or $op eq '--') {
					if ($ctx !~ /[WOB]x[^W]|[^W]x[WOB]/) {
						print "need space one side of that '$op' $at\n";
						print "$hereptr";
						$clean = 0;
					}

				# & is both unary and binary
				# unary:
				# 	a &b
				# binary (consistent spacing):
				#	a&b		OK
				#	a & b		OK
				#
				# boiling down to: if there is a space on the right then there
				# should be one on the left.
				#
				# - is the same
				#
				} elsif ($op eq '&' or $op eq '-') {
					if ($ctx !~ /VxV|[EW]x[WE]|[EWB]x[VO]/) {
						print "need space before that '$op' $at\n";
						print "$hereptr";
						$clean = 0;
					}

				# * is the same as & only adding:
				# type:
				# 	(foo *)
				#	(foo **)
				#
				} elsif ($op eq '*') {
					if ($ca eq '*') {
						if ($cc =~ /\s/) {
							print "no space after that '$op' $at\n";
							print "$hereptr";
							$clean = 0;
						}
					} elsif ($ctx !~ /VxV|[EW]x[WE]|[EWB]x[VO]|OxV|WxB/) {
						print "need space before that '$op' $at\n";
						print "$hereptr";
						$clean = 0;
					}

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

				# All the others need spaces both sides.
				} elsif ($ctx !~ /[EW]x[WE]/) {
					print "need spaces around that '$op' $at\n";
					print "$hereptr";
					$clean = 0;
				}
				$off += length($elements[$n + 1]);
			}
		}

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

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

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

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

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

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

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

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

#if/while/etc brace do not go on next line, unless #defining a do while loop, or if that brace on the next line is for something else
		if ($prevline=~/\b(if|while|for|switch)\s*\(/) {
			my @opened = $prevline=~/\(/g;
			my @closed = $prevline=~/\)/g;
			my $nr_line = $linenr;
			my $remaining = $realcnt - 1;
			my $next_line = $line;
			my $extra_lines = 0;
			my $display_segment = $prevline;

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

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

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

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

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

# don't use deprecated functions
		for my $func (@dep_functions) {
			if ($line =~ /\b$func\b/) {
				print "Don't use $func(): see Documentation/feature-removal-schedule.txt\n";
				print "$herecurr";
				$clean = 0;
			}
		}

# no volatiles please
		if ($line =~ /\bvolatile\b/ && $line !~ /\basm\s+volatile\b/) {
			print "Use of volatile is usually wrong: see Documentation/volatile-considered-harmful.txt\n";
			print "$herecurr";
			$clean = 0;
		}

# warn about #if 0
		if ($line =~ /^.#\s*if\s+0\b/) {
			print "#if 0 -- if this code redundant remove it\n";
			print "$herecurr";
			$clean = 0;
		}

# 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)) {
				print "$1 definition without comment\n";
				print "$herecurr";
				$clean = 0;
			}
		}
# check for memory barriers without a comment.
		if ($line =~ /\b(mb|rmb|wmb|read_barrier_depends|smp_mb|smp_rmb|smp_wmb|smp_read_barrier_depends)\(/) {
			if (!ctx_has_comment($first_line, $linenr)) {
				print "memory barrier without comment\n";
				print "$herecurr";
				$clean = 0;
			}
		}
# check of hardware specific defines
		if ($line =~ m@^.#\s*if.*\b(__i386__|__powerpc64__|__sun__|__s390x__)\b@) {
			print "architecture specific defines should be avoided\n";
			print "$herecurr";
			$clean = 0;
		}
	}

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

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