xref: /illumos-gate/usr/src/tools/scripts/cstyle.pl (revision 8119dad84d6416f13557b0ba8e2aaf9064cbcfd3)
1#!/usr/bin/perl -w
2#
3# CDDL HEADER START
4#
5# The contents of this file are subject to the terms of the
6# Common Development and Distribution License (the "License").
7# You may not use this file except in compliance with the License.
8#
9# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10# or http://www.opensolaris.org/os/licensing.
11# See the License for the specific language governing permissions
12# and limitations under the License.
13#
14# When distributing Covered Code, include this CDDL HEADER in each
15# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16# If applicable, add the following below this CDDL HEADER, with the
17# fields enclosed by brackets "[]" replaced with your own identifying
18# information: Portions Copyright [yyyy] [name of copyright owner]
19#
20# CDDL HEADER END
21#
22# Copyright 2015 Toomas Soome <tsoome@me.com>
23# Copyright 2016 Nexenta Systems, Inc.
24# Copyright 2023 Oxide Computer Company
25#
26# Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
27# Use is subject to license terms.
28#
29# Copyright (c) 2015 by Delphix. All rights reserved.
30#
31# @(#)cstyle 1.58 98/09/09 (from shannon)
32#
33# cstyle - check for some common stylistic errors.
34#
35#	cstyle is a sort of "lint" for C coding style.
36#	It attempts to check for the style used in the
37#	kernel, sometimes known as "Bill Joy Normal Form".
38#
39#	There's a lot this can't check for, like proper indentation
40#	of code blocks.  There's also a lot more this could check for.
41#
42#	A note to the non perl literate:
43#
44#		perl regular expressions are pretty much like egrep
45#		regular expressions, with the following special symbols
46#
47#		\s	any space character
48#		\S	any non-space character
49#		\w	any "word" character [a-zA-Z0-9_]
50#		\W	any non-word character
51#		\d	a digit [0-9]
52#		\D	a non-digit
53#		\b	word boundary (between \w and \W)
54#		\B	non-word boundary
55#
56
57require 5.0;
58use IO::File;
59use Getopt::Std;
60use strict;
61
62my $usage =
63"usage: cstyle [-chpvCP] [-o constructs] file ...
64	-c	check continuation indentation inside functions
65	-h	perform heuristic checks that are sometimes wrong
66	-p	perform some of the more picky checks
67	-v	verbose
68	-C	don't check anything in header block comments
69	-P	check for use of non-POSIX types
70	-o constructs
71		allow a comma-seperated list of optional constructs:
72		    doxygen	allow doxygen-style block comments (/** /*!)
73		    splint	allow splint-style lint comments (/*@ ... @*/)
74";
75
76my %opts;
77
78if (!getopts("cho:pvCP", \%opts)) {
79	print $usage;
80	exit 2;
81}
82
83my $check_continuation = $opts{'c'};
84my $heuristic = $opts{'h'};
85my $picky = $opts{'p'};
86my $verbose = $opts{'v'};
87my $ignore_hdr_comment = $opts{'C'};
88my $check_posix_types = $opts{'P'};
89
90my $doxygen_comments = 0;
91my $splint_comments = 0;
92
93if (defined($opts{'o'})) {
94	for my $x (split /,/, $opts{'o'}) {
95		if ($x eq "doxygen") {
96			$doxygen_comments = 1;
97		} elsif ($x eq "splint") {
98			$splint_comments = 1;
99		} else {
100			print "cstyle: unrecognized construct \"$x\"\n";
101			print $usage;
102			exit 2;
103		}
104	}
105}
106
107my ($filename, $line, $prev);		# shared globals
108
109my $fmt;
110my $hdr_comment_start;
111
112if ($verbose) {
113	$fmt = "%s: %d: %s\n%s\n";
114} else {
115	$fmt = "%s: %d: %s\n";
116}
117
118if ($doxygen_comments) {
119	# doxygen comments look like "/*!" or "/**"; allow them.
120	$hdr_comment_start = qr/^\s*\/\*[\!\*]?$/;
121} else {
122	$hdr_comment_start = qr/^\s*\/\*$/;
123}
124
125# FreeBSD uses comments styled as such for their license headers:
126# /*-
127#  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
128#  *
129#  ...
130#
131# In order to apply other cstyle checks to those files without stumbling over
132# the license header, tolerate such comment openings as well.
133my $fbsd_comment_start = qr/^\s*\/\*-$/;
134
135# Note, following must be in single quotes so that \s and \w work right.
136my $typename = '(int|char|short|long|unsigned|float|double' .
137    '|\w+_t|struct\s+\w+|union\s+\w+|FILE)';
138
139# mapping of old types to POSIX compatible types
140my %old2posix = (
141	'unchar' => 'uchar_t',
142	'ushort' => 'ushort_t',
143	'uint' => 'uint_t',
144	'ulong' => 'ulong_t',
145	'u_int' => 'uint_t',
146	'u_short' => 'ushort_t',
147	'u_long' => 'ulong_t',
148	'u_char' => 'uchar_t',
149	'u_int8_t' => 'uint8_t',
150	'u_int16_t' => 'uint16_t',
151	'u_int32_t' => 'uint32_t',
152	'u_int64_t' => 'uint64_t',
153	'u_quad_t' => 'uint64_t',
154	'quad' => 'quad_t'
155);
156
157my $lint_re = qr/\/\*(?:
158	ARGSUSED[0-9]*|NOTREACHED|LINTLIBRARY|VARARGS[0-9]*|
159	CONSTCOND|CONSTANTCOND|CONSTANTCONDITION|EMPTY|
160	FALLTHRU|FALLTHROUGH|LINTED.*?|PRINTFLIKE[0-9]*|
161	PROTOLIB[0-9]*|SCANFLIKE[0-9]*|CSTYLED.*?
162    )\*\//x;
163
164my $splint_re = qr/\/\*@.*?@\*\//x;
165
166my $warlock_re = qr/\/\*\s*(?:
167	VARIABLES\ PROTECTED\ BY|
168	MEMBERS\ PROTECTED\ BY|
169	ALL\ MEMBERS\ PROTECTED\ BY|
170	READ-ONLY\ VARIABLES:|
171	READ-ONLY\ MEMBERS:|
172	VARIABLES\ READABLE\ WITHOUT\ LOCK:|
173	MEMBERS\ READABLE\ WITHOUT\ LOCK:|
174	LOCKS\ COVERED\ BY|
175	LOCK\ UNNEEDED\ BECAUSE|
176	LOCK\ NEEDED:|
177	LOCK\ HELD\ ON\ ENTRY:|
178	READ\ LOCK\ HELD\ ON\ ENTRY:|
179	WRITE\ LOCK\ HELD\ ON\ ENTRY:|
180	LOCK\ ACQUIRED\ AS\ SIDE\ EFFECT:|
181	READ\ LOCK\ ACQUIRED\ AS\ SIDE\ EFFECT:|
182	WRITE\ LOCK\ ACQUIRED\ AS\ SIDE\ EFFECT:|
183	LOCK\ RELEASED\ AS\ SIDE\ EFFECT:|
184	LOCK\ UPGRADED\ AS\ SIDE\ EFFECT:|
185	LOCK\ DOWNGRADED\ AS\ SIDE\ EFFECT:|
186	FUNCTIONS\ CALLED\ THROUGH\ POINTER|
187	FUNCTIONS\ CALLED\ THROUGH\ MEMBER|
188	LOCK\ ORDER:
189    )/x;
190
191my $err_stat = 0;		# exit status
192
193if ($#ARGV >= 0) {
194	foreach my $arg (@ARGV) {
195		my $fh = new IO::File $arg, "r";
196		if (!defined($fh)) {
197			printf "%s: can not open\n", $arg;
198		} else {
199			&cstyle($arg, $fh);
200			close $fh;
201		}
202	}
203} else {
204	&cstyle("<stdin>", *STDIN);
205}
206exit $err_stat;
207
208my $no_errs = 0;		# set for CSTYLED-protected lines
209
210sub err($) {
211	my ($error) = @_;
212	unless ($no_errs) {
213		if ($verbose) {
214			printf $fmt, $filename, $., $error, $line;
215		} else {
216			printf $fmt, $filename, $., $error;
217		}
218		$err_stat = 1;
219	}
220}
221
222sub err_prefix($$) {
223	my ($prevline, $error) = @_;
224	my $out = $prevline."\n".$line;
225	unless ($no_errs) {
226		if ($verbose) {
227			printf $fmt, $filename, $., $error, $out;
228		} else {
229			printf $fmt, $filename, $., $error;
230		}
231		$err_stat = 1;
232	}
233}
234
235sub err_prev($) {
236	my ($error) = @_;
237	unless ($no_errs) {
238		if ($verbose) {
239			printf $fmt, $filename, $. - 1, $error, $prev;
240		} else {
241			printf $fmt, $filename, $. - 1, $error;
242		}
243		$err_stat = 1;
244	}
245}
246
247sub cstyle($$) {
248
249my ($fn, $filehandle) = @_;
250$filename = $fn;			# share it globally
251
252my $in_cpp = 0;
253my $next_in_cpp = 0;
254
255my $in_comment = 0;
256my $in_header_comment = 0;
257my $comment_done = 0;
258my $in_warlock_comment = 0;
259my $in_function = 0;
260my $in_function_header = 0;
261my $function_header_full_indent = 0;
262my $in_declaration = 0;
263my $note_level = 0;
264my $nextok = 0;
265my $nocheck = 0;
266
267my $in_string = 0;
268
269my ($okmsg, $comment_prefix);
270
271$line = '';
272$prev = '';
273reset_indent();
274
275line: while (<$filehandle>) {
276	s/\r?\n$//;	# strip return and newline
277
278	# save the original line, then remove all text from within
279	# double or single quotes, we do not want to check such text.
280
281	$line = $_;
282
283	#
284	# C allows strings to be continued with a backslash at the end of
285	# the line.  We translate that into a quoted string on the previous
286	# line followed by an initial quote on the next line.
287	#
288	# (we assume that no-one will use backslash-continuation with character
289	# constants)
290	#
291	$_ = '"' . $_		if ($in_string && !$nocheck && !$in_comment);
292
293	#
294	# normal strings and characters
295	#
296	s/'([^\\']|\\[^xX0]|\\0[0-9]*|\\[xX][0-9a-fA-F]*)'/''/g;
297	s/"([^\\"]|\\.)*"/\"\"/g;
298
299	#
300	# detect string continuation
301	#
302	if ($nocheck || $in_comment) {
303		$in_string = 0;
304	} else {
305		#
306		# Now that all full strings are replaced with "", we check
307		# for unfinished strings continuing onto the next line.
308		#
309		$in_string =
310		    (s/([^"](?:"")*)"([^\\"]|\\.)*\\$/$1""/ ||
311		    s/^("")*"([^\\"]|\\.)*\\$/""/);
312	}
313
314	#
315	# figure out if we are in a cpp directive
316	#
317	$in_cpp = $next_in_cpp || /^\s*#/;	# continued or started
318	$next_in_cpp = $in_cpp && /\\$/;	# only if continued
319
320	# strip off trailing backslashes, which appear in long macros
321	s/\s*\\$//;
322
323	# an /* END CSTYLED */ comment ends a no-check block.
324	if ($nocheck) {
325		if (/\/\* *END *CSTYLED *\*\//) {
326			$nocheck = 0;
327		} else {
328			reset_indent();
329			next line;
330		}
331	}
332
333	# a /*CSTYLED*/ comment indicates that the next line is ok.
334	if ($nextok) {
335		if ($okmsg) {
336			err($okmsg);
337		}
338		$nextok = 0;
339		$okmsg = 0;
340		if (/\/\* *CSTYLED.*\*\//) {
341			/^.*\/\* *CSTYLED *(.*) *\*\/.*$/;
342			$okmsg = $1;
343			$nextok = 1;
344		}
345		$no_errs = 1;
346	} elsif ($no_errs) {
347		$no_errs = 0;
348	}
349
350	# check length of line.
351	# first, a quick check to see if there is any chance of being too long.
352	if (($line =~ tr/\t/\t/) * 7 + length($line) > 80) {
353		# yes, there is a chance.
354		# replace tabs with spaces and check again.
355		my $eline = $line;
356		1 while $eline =~
357		    s/\t+/' ' x (length($&) * 8 - length($`) % 8)/e;
358		if (length($eline) > 80) {
359			err("line > 80 characters");
360		}
361	}
362
363	# ignore NOTE(...) annotations (assumes NOTE is on lines by itself).
364	if ($note_level || /\b_?NOTE\s*\(/) { # if in NOTE or this is NOTE
365		s/[^()]//g;			  # eliminate all non-parens
366		$note_level += s/\(//g - length;  # update paren nest level
367		next;
368	}
369
370	# a /* BEGIN CSTYLED */ comment starts a no-check block.
371	if (/\/\* *BEGIN *CSTYLED *\*\//) {
372		$nocheck = 1;
373	}
374
375	# a /*CSTYLED*/ comment indicates that the next line is ok.
376	if (/\/\* *CSTYLED.*\*\//) {
377		/^.*\/\* *CSTYLED *(.*) *\*\/.*$/;
378		$okmsg = $1;
379		$nextok = 1;
380	}
381	if (/\/\/ *CSTYLED/) {
382		/^.*\/\/ *CSTYLED *(.*)$/;
383		$okmsg = $1;
384		$nextok = 1;
385	}
386
387	# universal checks; apply to everything
388	if (/\t +\t/) {
389		err("spaces between tabs");
390	}
391	if (/ \t+ /) {
392		err("tabs between spaces");
393	}
394	if (/\s$/) {
395		err("space or tab at end of line");
396	}
397	if (/[^ \t(]\/\*/ && !/\w\(\/\*.*\*\/\);/) {
398		err("comment preceded by non-blank");
399	}
400
401	# is this the beginning or ending of a function?
402	# (not if "struct foo\n{\n")
403	if (/^\{$/ && $prev =~ /\)\s*(const\s*)?(\/\*.*\*\/\s*)?\\?$/) {
404		$in_function = 1;
405		$in_declaration = 1;
406		$in_function_header = 0;
407		$function_header_full_indent = 0;
408		$prev = $line;
409		next line;
410	}
411	if (/^\}\s*(\/\*.*\*\/\s*)*$/) {
412		if ($prev =~ /^\s*return\s*;/) {
413			err_prev("unneeded return at end of function");
414		}
415		$in_function = 0;
416		reset_indent();		# we don't check between functions
417		$prev = $line;
418		next line;
419	}
420	if ($in_function_header && ! /^    (\w|\.)/ ) {
421		if (/^\{\}$/) {
422			$in_function_header = 0;
423			$function_header_full_indent = 0;
424		} elsif ($picky && ! (/^\t/ && $function_header_full_indent != 0)) {
425			err("continuation line should be indented by 4 spaces");
426		}
427	}
428
429	#
430	# If this matches something of form "foo(", it's probably a function
431	# definition, unless it ends with ") bar;", in which case it's a declaration
432	# that uses a macro to generate the type.
433	#
434	if (/^\w+\(/ && !/\) \w+;$/) {
435		$in_function_header = 1;
436		if (/\($/) {
437			$function_header_full_indent = 1;
438		}
439	}
440	if ($in_function_header && /^\{$/) {
441		$in_function_header = 0;
442		$function_header_full_indent = 0;
443		$in_function = 1;
444	}
445	if ($in_function_header && /\);$/) {
446		$in_function_header = 0;
447		$function_header_full_indent = 0;
448	}
449	if ($in_function_header && /\{$/ ) {
450		if ($picky) {
451			err("opening brace on same line as function header");
452		}
453		$in_function_header = 0;
454		$function_header_full_indent = 0;
455		$in_function = 1;
456		next line;
457	}
458
459	if ($in_warlock_comment && /\*\//) {
460		$in_warlock_comment = 0;
461		$prev = $line;
462		next line;
463	}
464
465	# a blank line terminates the declarations within a function.
466	# XXX - but still a problem in sub-blocks.
467	if ($in_declaration && /^$/) {
468		$in_declaration = 0;
469	}
470
471	if ($comment_done) {
472		$in_comment = 0;
473		$in_header_comment = 0;
474		$comment_done = 0;
475	}
476	# does this looks like the start of a block comment?
477	if (/$hdr_comment_start/ || /$fbsd_comment_start/) {
478		if (!/^\t*\/\*/) {
479			err("block comment not indented by tabs");
480		}
481		$in_comment = 1;
482		/^(\s*)\//;
483		$comment_prefix = $1;
484		if ($comment_prefix eq "") {
485			$in_header_comment = 1;
486		}
487		$prev = $line;
488		next line;
489	}
490	# are we still in the block comment?
491	if ($in_comment) {
492		if (/^$comment_prefix \*\/$/) {
493			$comment_done = 1;
494		} elsif (/\*\//) {
495			$comment_done = 1;
496			err("improper block comment close")
497			    unless ($ignore_hdr_comment && $in_header_comment);
498		} elsif (!/^$comment_prefix \*[ \t]/ &&
499		    !/^$comment_prefix \*$/) {
500			err("improper block comment")
501			    unless ($ignore_hdr_comment && $in_header_comment);
502		}
503	}
504
505	if ($in_header_comment && $ignore_hdr_comment) {
506		$prev = $line;
507		next line;
508	}
509
510	# check for errors that might occur in comments and in code.
511
512	# allow spaces to be used to draw pictures in header comments.
513	if (/[^ ]     / && !/".*     .*"/ && !$in_header_comment) {
514		err("spaces instead of tabs");
515	}
516	if (/^ / && !/^ \*[ \t\/]/ && !/^ \*$/ &&
517	    (!/^    (\w|\.)/ || $in_function != 0)) {
518		err("indent by spaces instead of tabs");
519	}
520	if (/^\t+ [^ \t\*]/ || /^\t+  \S/ || /^\t+   \S/) {
521		err("continuation line not indented by 4 spaces");
522	}
523	if (/$warlock_re/ && !/\*\//) {
524		$in_warlock_comment = 1;
525		$prev = $line;
526		next line;
527	}
528	if (/^\s*\/\*./ && !/^\s*\/\*.*\*\// && !/$hdr_comment_start/) {
529		err("improper first line of block comment");
530	}
531
532	if ($in_comment) {	# still in comment, don't do further checks
533		$prev = $line;
534		next line;
535	}
536
537	if ((/[^(]\/\*\S/ || /^\/\*\S/) &&
538	    !(/$lint_re/ || ($splint_comments && /$splint_re/))) {
539		err("missing blank after open comment");
540	}
541	if (/\S\*\/[^)]|\S\*\/$/ &&
542	    !(/$lint_re/ || ($splint_comments && /$splint_re/))) {
543		err("missing blank before close comment");
544	}
545	if (/\/\/\S/) {		# C++ comments
546		err("missing blank after start comment");
547	}
548	# check for unterminated single line comments, but allow them when
549	# they are used to comment out the argument list of a function
550	# declaration.
551	if (/\S.*\/\*/ && !/\S.*\/\*.*\*\// && !/\(\/\*/) {
552		err("unterminated single line comment");
553	}
554
555	if (/^(#else|#endif|#include)(.*)$/) {
556		$prev = $line;
557		if ($picky) {
558			my $directive = $1;
559			my $clause = $2;
560			# Enforce ANSI rules for #else and #endif: no noncomment
561			# identifiers are allowed after #endif or #else.  Allow
562			# C++ comments since they seem to be a fact of life.
563			if ((($1 eq "#endif") || ($1 eq "#else")) &&
564			    ($clause ne "") &&
565			    (!($clause =~ /^\s+\/\*.*\*\/$/)) &&
566			    (!($clause =~ /^\s+\/\/.*$/))) {
567				err("non-comment text following " .
568				    "$directive (or malformed $directive " .
569				    "directive)");
570			}
571		}
572		next line;
573	}
574
575	#
576	# delete any comments and check everything else.  Note that
577	# ".*?" is a non-greedy match, so that we don't get confused by
578	# multiple comments on the same line.
579	#
580	s/\/\*.*?\*\///g;
581	s/\/\/.*$//;		# C++ comments
582
583	# delete any trailing whitespace; we have already checked for that.
584	s/\s*$//;
585
586	# following checks do not apply to text in comments.
587
588	if (/[^<>\s][!<>=]=/ || /[^<>][!<>=]=[^\s,]/ ||
589	    (/[^->]>[^,=>\s]/ && !/[^->]>$/) ||
590	    (/[^<]<[^,=<\s]/ && !/[^<]<$/) ||
591	    /[^<\s]<[^<]/ || /[^->\s]>[^>]/) {
592		err("missing space around relational operator");
593	}
594	if (/\S>>=/ || /\S<<=/ || />>=\S/ || /<<=\S/ || /\S[-+*\/&|^%]=/ ||
595	    (/[^-+*\/&|^%!<>=\s]=[^=]/ && !/[^-+*\/&|^%!<>=\s]=$/) ||
596	    (/[^!<>=]=[^=\s]/ && !/[^!<>=]=$/)) {
597		# XXX - should only check this for C++ code
598		# XXX - there are probably other forms that should be allowed
599		if (!/\soperator=/) {
600			err("missing space around assignment operator");
601		}
602	}
603	if (/[,;]\S/ && !/\bfor \(;;\)/) {
604		err("comma or semicolon followed by non-blank");
605	}
606	# allow "for" statements to have empty "while" clauses
607	if (/\s[,;]/ && !/^[\t]+;$/ && !/^\s*for \([^;]*; ;[^;]*\)/) {
608		err("comma or semicolon preceded by blank");
609	}
610	if (/^\s*(&&|\|\|)/) {
611		err("improper boolean continuation");
612	}
613	if (/\S   *(&&|\|\|)/ || /(&&|\|\|)   *\S/) {
614		err("more than one space around boolean operator");
615	}
616	if (/\b(for|if|while|switch|sizeof|alignof|return|case)\(/) {
617		err("missing space between keyword and paren");
618	}
619	if (/(\b(for|if|while|switch|return)\b.*){2,}/ && !/^#define/) {
620		# multiple "case" and "sizeof" allowed
621		err("more than one keyword on line");
622	}
623	if (/\b(for|if|while|switch|sizeof|alignof|return|case)\s\s+\(/ &&
624	    !/^#if\s+\(/) {
625		err("extra space between keyword and paren");
626	}
627	# try to detect "func (x)" but not "if (x)" or
628	# "#define foo (x)" or "int (*func)();"
629	if (/\w\s\(/) {
630		my $s = $_;
631		# strip off all keywords on the line
632		s/\b(for|if|while|switch|return|case|alignof|sizeof)\s\(/XXX(/g;
633		s/#elif\s\(/XXX(/g;
634		s/^#define\s+\w+\s+\(/XXX(/;
635		# do not match things like "void (*f)();"
636		# or "typedef void (func_t)();"
637		s/\w\s\(+\*/XXX(*/g;
638		s/\b($typename|void)\s+\(+/XXX(/og;
639		if (/\w\s\(/) {
640			err("extra space between function name and left paren");
641		}
642		$_ = $s;
643	}
644	# try to detect "int foo(x)", but not "extern int foo(x);"
645	# XXX - this still trips over too many legitimate things,
646	# like "int foo(x,\n\ty);"
647#		if (/^(\w+(\s|\*)+)+\w+\(/ && !/\)[;,](\s|)*$/ &&
648#		    !/^(extern|static)\b/) {
649#			err("return type of function not on separate line");
650#		}
651	# this is a close approximation
652	if (/^(\w+(\s|\*)+)+\w+\(.*\)(\s|)*$/ &&
653	    !/^(extern|static)\b/) {
654		err("return type of function not on separate line");
655	}
656	if (/^#define /) {
657		err("#define followed by space instead of tab");
658	}
659	if (/^\s*return\W[^;]*;/ && !/^\s*return\s*\(.*\);/) {
660		err("unparenthesized return expression");
661	}
662	if (/\bsizeof\b/ && !/\bsizeof\s*\(.*\)/) {
663		err("unparenthesized sizeof expression");
664	}
665	if (/\balignof\b/ && !/\balignof\s*\(.*\)/) {
666		err("unparenthesized alignof expression");
667	}
668	if (/\(\s/) {
669		err("whitespace after left paren");
670	}
671	# allow "for" statements to have empty "continue" clauses
672	if (/\s\)/ && !/^\s*for \([^;]*;[^;]*; \)/) {
673		err("whitespace before right paren");
674	}
675	if (/^\s*\(void\)[^ ]/) {
676		err("missing space after (void) cast");
677	}
678	if (/\S\{/ && !/\{\{/) {
679		err("missing space before left brace");
680	}
681	if ($in_function && /^\s+\{/ &&
682	    ($prev =~ /\)\s*$/ || $prev =~ /\bstruct\s+\w+$/)) {
683		err("left brace starting a line");
684	}
685	if (/\}(else|while)/) {
686		err("missing space after right brace");
687	}
688	if (/\}\s\s+(else|while)/) {
689		err("extra space after right brace");
690	}
691	if (/\b_VOID\b|\bVOID\b|\bSTATIC\b/) {
692		err("obsolete use of VOID or STATIC");
693	}
694	if (/\b$typename\*/o) {
695		err("missing space between type name and *");
696	}
697	if (/^\s+#/) {
698		err("preprocessor statement not in column 1");
699	}
700	if (/^#\s/) {
701		err("blank after preprocessor #");
702	}
703	if (/!\s*(strcmp|strncmp|bcmp)\s*\(/) {
704		err("don't use boolean ! with comparison functions");
705	}
706
707	#
708	# We completely ignore, for purposes of indentation:
709	#  * lines outside of functions
710	#  * preprocessor lines
711	#
712	if ($check_continuation && $in_function && !$in_cpp) {
713		process_indent($_);
714	}
715	if ($picky) {
716		# try to detect spaces after casts, but allow (e.g.)
717		# "sizeof (int) + 1", "void (*funcptr)(int) = foo;", and
718		# "int foo(int) __NORETURN;"
719		if ((/^\($typename( \*+)?\)\s/o ||
720		    /\W\($typename( \*+)?\)\s/o) &&
721		    !/sizeof\s*\($typename( \*)?\)\s/o &&
722		    !/\($typename( \*+)?\)\s+=[^=]/o) {
723			err("space after cast");
724		}
725		if (/\b$typename\s*\*\s/o &&
726		    !/\b$typename\s*\*\s+const\b/o) {
727			err("unary * followed by space");
728		}
729	}
730	if ($check_posix_types) {
731		# try to detect old non-POSIX types.
732		# POSIX requires all non-standard typedefs to end in _t,
733		# but historically these have been used.
734		my $types = join '|', keys %old2posix;
735		if (/\b($types)\b/) {
736			err("non-POSIX typedef $1 used: use $old2posix{$1} instead");
737		}
738	}
739	if ($heuristic) {
740		# cannot check this everywhere due to "struct {\n...\n} foo;"
741		if ($in_function && !$in_declaration &&
742		    /\}./ && !/\}\s+=/ && !/\{.*\}[;,]$/ && !/\}(\s|)*$/ &&
743		    !/\} (else|while)/ && !/\}\}/) {
744			err("possible bad text following right brace");
745		}
746		# cannot check this because sub-blocks in
747		# the middle of code are ok
748		if ($in_function && /^\s+\{/) {
749			err("possible left brace starting a line");
750		}
751	}
752	if (/^\s*else\W/) {
753		if ($prev =~ /^\s*\}$/) {
754			err_prefix($prev,
755			    "else and right brace should be on same line");
756		}
757	}
758	$prev = $line;
759}
760
761if ($prev eq "") {
762	err("last line in file is blank");
763}
764
765}
766
767#
768# Continuation-line checking
769#
770# The rest of this file contains the code for the continuation checking
771# engine.  It's a pretty simple state machine which tracks the expression
772# depth (unmatched '('s and '['s).
773#
774# Keep in mind that the argument to process_indent() has already been heavily
775# processed; all comments have been replaced by control-A, and the contents of
776# strings and character constants have been elided.
777#
778
779my $cont_in;		# currently inside of a continuation
780my $cont_off;		# skipping an initializer or definition
781my $cont_noerr;		# suppress cascading errors
782my $cont_start;		# the line being continued
783my $cont_base;		# the base indentation
784my $cont_first;		# this is the first line of a statement
785my $cont_multiseg;	# this continuation has multiple segments
786
787my $cont_special;	# this is a C statement (if, for, etc.)
788my $cont_macro;		# this is a macro
789my $cont_case;		# this is a multi-line case
790
791my @cont_paren;		# the stack of unmatched ( and [s we've seen
792
793sub
794reset_indent()
795{
796	$cont_in = 0;
797	$cont_off = 0;
798}
799
800sub
801delabel($)
802{
803	#
804	# replace labels with tabs.  Note that there may be multiple
805	# labels on a line.
806	#
807	local $_ = $_[0];
808
809	while (/^(\t*)( *(?:(?:\w+\s*)|(?:case\b[^:]*)): *)(.*)$/) {
810		my ($pre_tabs, $label, $rest) = ($1, $2, $3);
811		$_ = $pre_tabs;
812		while ($label =~ s/^([^\t]*)(\t+)//) {
813			$_ .= "\t" x (length($2) + length($1) / 8);
814		}
815		$_ .= ("\t" x (length($label) / 8)).$rest;
816	}
817
818	return ($_);
819}
820
821sub
822process_indent($)
823{
824	require strict;
825	local $_ = $_[0];			# preserve the global $_
826
827	s///g;	# No comments
828	s/\s+$//;	# Strip trailing whitespace
829
830	return			if (/^$/);	# skip empty lines
831
832	# regexps used below; keywords taking (), macros, and continued cases
833	my $special = '(?:(?:\}\s*)?else\s+)?(?:if|for|while|switch)\b';
834	my $macro = '[A-Z_][A-Z_0-9]*\(';
835	my $case = 'case\b[^:]*$';
836
837	# skip over enumerations, array definitions, initializers, etc.
838	if ($cont_off <= 0 && !/^\s*$special/ &&
839	    (/(?:(?:\b(?:enum|struct|union)\s*[^\{]*)|(?:\s+=\s*))\{/ ||
840	    (/^\s*\{/ && $prev =~ /=\s*(?:\/\*.*\*\/\s*)*$/))) {
841		$cont_in = 0;
842		$cont_off = tr/{/{/ - tr/}/}/;
843		return;
844	}
845	if ($cont_off) {
846		$cont_off += tr/{/{/ - tr/}/}/;
847		return;
848	}
849
850	if (!$cont_in) {
851		$cont_start = $line;
852
853		if (/^\t* /) {
854			err("non-continuation indented 4 spaces");
855			$cont_noerr = 1;		# stop reporting
856		}
857		$_ = delabel($_);	# replace labels with tabs
858
859		# check if the statement is complete
860		return		if (/^\s*\}?$/);
861		return		if (/^\s*\}?\s*else\s*\{?$/);
862		return		if (/^\s*do\s*\{?$/);
863		return		if (/\{$/);
864		return		if (/\}[,;]?$/);
865
866		# Allow macros on their own lines
867		return		if (/^\s*[A-Z_][A-Z_0-9]*$/);
868
869		# cases we don't deal with, generally non-kosher
870		if (/\{/) {
871			err("stuff after {");
872			return;
873		}
874
875		# Get the base line, and set up the state machine
876		/^(\t*)/;
877		$cont_base = $1;
878		$cont_in = 1;
879		@cont_paren = ();
880		$cont_first = 1;
881		$cont_multiseg = 0;
882
883		# certain things need special processing
884		$cont_special = /^\s*$special/? 1 : 0;
885		$cont_macro = /^\s*$macro/? 1 : 0;
886		$cont_case = /^\s*$case/? 1 : 0;
887	} else {
888		$cont_first = 0;
889
890		# Strings may be pulled back to an earlier (half-)tabstop
891		unless ($cont_noerr || /^$cont_base    / ||
892		    (/^\t*(?:    )?(?:gettext\()?\"/ && !/^$cont_base\t/)) {
893			err_prefix($cont_start,
894			    "continuation should be indented 4 spaces");
895		}
896	}
897
898	my $rest = $_;			# keeps the remainder of the line
899
900	#
901	# The split matches 0 characters, so that each 'special' character
902	# is processed separately.  Parens and brackets are pushed and
903	# popped off the @cont_paren stack.  For normal processing, we wait
904	# until a ; or { terminates the statement.  "special" processing
905	# (if/for/while/switch) is allowed to stop when the stack empties,
906	# as is macro processing.  Case statements are terminated with a :
907	# and an empty paren stack.
908	#
909	foreach $_ (split /[^\(\)\[\]\{\}\;\:]*/) {
910		next		if (length($_) == 0);
911
912		# rest contains the remainder of the line
913		my $rxp = "[^\Q$_\E]*\Q$_\E";
914		$rest =~ s/^$rxp//;
915
916		if (/\(/ || /\[/) {
917			push @cont_paren, $_;
918		} elsif (/\)/ || /\]/) {
919			my $cur = $_;
920			tr/\)\]/\(\[/;
921
922			my $old = (pop @cont_paren);
923			if (!defined($old)) {
924				err("unexpected '$cur'");
925				$cont_in = 0;
926				last;
927			} elsif ($old ne $_) {
928				err("'$cur' mismatched with '$old'");
929				$cont_in = 0;
930				last;
931			}
932
933			#
934			# If the stack is now empty, do special processing
935			# for if/for/while/switch and macro statements.
936			#
937			next		if (@cont_paren != 0);
938			if ($cont_special) {
939				if ($rest =~ /^\s*\{?$/) {
940					$cont_in = 0;
941					last;
942				}
943				if ($rest =~ /^\s*;$/) {
944					err("empty if/for/while body ".
945					    "not on its own line");
946					$cont_in = 0;
947					last;
948				}
949				if (!$cont_first && $cont_multiseg == 1) {
950					err_prefix($cont_start,
951					    "multiple statements continued ".
952					    "over multiple lines");
953					$cont_multiseg = 2;
954				} elsif ($cont_multiseg == 0) {
955					$cont_multiseg = 1;
956				}
957				# We've finished this section, start
958				# processing the next.
959				goto section_ended;
960			}
961			if ($cont_macro) {
962				if ($rest =~ /^$/) {
963					$cont_in = 0;
964					last;
965				}
966			}
967		} elsif (/\;/) {
968			if ($cont_case) {
969				err("unexpected ;");
970			} elsif (!$cont_special) {
971				err("unexpected ;")	if (@cont_paren != 0);
972				if (!$cont_first && $cont_multiseg == 1) {
973					err_prefix($cont_start,
974					    "multiple statements continued ".
975					    "over multiple lines");
976					$cont_multiseg = 2;
977				} elsif ($cont_multiseg == 0) {
978					$cont_multiseg = 1;
979				}
980				if ($rest =~ /^$/) {
981					$cont_in = 0;
982					last;
983				}
984				if ($rest =~ /^\s*special/) {
985					err("if/for/while/switch not started ".
986					    "on its own line");
987				}
988				goto section_ended;
989			}
990		} elsif (/\{/) {
991			err("{ while in parens/brackets") if (@cont_paren != 0);
992			err("stuff after {")		if ($rest =~ /[^\s}]/);
993			$cont_in = 0;
994			last;
995		} elsif (/\}/) {
996			err("} while in parens/brackets") if (@cont_paren != 0);
997			if (!$cont_special && $rest !~ /^\s*(while|else)\b/) {
998				if ($rest =~ /^$/) {
999					err("unexpected }");
1000				} else {
1001					err("stuff after }");
1002				}
1003				$cont_in = 0;
1004				last;
1005			}
1006		} elsif (/\:/ && $cont_case && @cont_paren == 0) {
1007			err("stuff after multi-line case") if ($rest !~ /$^/);
1008			$cont_in = 0;
1009			last;
1010		}
1011		next;
1012section_ended:
1013		# End of a statement or if/while/for loop.  Reset
1014		# cont_special and cont_macro based on the rest of the
1015		# line.
1016		$cont_special = ($rest =~ /^\s*$special/)? 1 : 0;
1017		$cont_macro = ($rest =~ /^\s*$macro/)? 1 : 0;
1018		$cont_case = 0;
1019		next;
1020	}
1021	$cont_noerr = 0			if (!$cont_in);
1022}
1023