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 #
  23 # Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24 # Use is subject to license terms.
  25 # Copyright 2015 Nexenta Systems, Inc.  All rights reserved.
  26 #
  27 # cstyle - check for some common stylistic errors.
  28 #
  29 #       cstyle is a sort of "lint" for C coding style.
  30 #       It attempts to check for the style used in the
  31 #       kernel, sometimes known as "Bill Joy Normal Form".
  32 #
  33 #       There's a lot this can't check for, like proper indentation
  34 #       of code blocks.  There's also a lot more this could check for.
  35 #
  36 #       A note to the non perl literate:
  37 #
  38 #               perl regular expressions are pretty much like egrep
  39 #               regular expressions, with the following special symbols
  40 #
  41 #               \s      any space character
  42 #               \S      any non-space character
  43 #               \w      any "word" character [a-zA-Z0-9_]
  44 #               \W      any non-word character
  45 #               \d      a digit [0-9]
  46 #               \D      a non-digit
  47 #               \b      word boundary (between \w and \W)
  48 #               \B      non-word boundary
  49 #
  50 
  51 require 5.0;
  52 use IO::File;
  53 use Getopt::Std;
  54 use strict;
  55 
  56 my $usage =
  57 "usage: cstyle [-chpvCP] [-o constructs] file ...
  58         -c      check continuation indentation inside functions
  59         -h      perform heuristic checks that are sometimes wrong
  60         -p      perform some of the more picky checks
  61         -v      verbose
  62         -C      don't check anything in header block comments
  63         -P      check for use of non-POSIX types
  64         -o constructs
  65                 allow a comma-seperated list of optional constructs:
  66                     doxygen     allow doxygen-style block comments (/** /*!)
  67                     splint      allow splint-style lint comments (/*@ ... @*/)
  68 ";
  69 
  70 my %opts;
  71 
  72 if (!getopts("cho:pvCP", \%opts)) {
  73         print $usage;
  74         exit 2;
  75 }
  76 
  77 my $check_continuation = $opts{'c'};
  78 my $heuristic = $opts{'h'};
  79 my $picky = $opts{'p'};
  80 my $verbose = $opts{'v'};
  81 my $ignore_hdr_comment = $opts{'C'};
  82 my $check_posix_types = $opts{'P'};
  83 
  84 my $doxygen_comments = 0;
  85 my $splint_comments = 0;
  86 
  87 if (defined($opts{'o'})) {
  88         for my $x (split /,/, $opts{'o'}) {
  89                 if ($x eq "doxygen") {
  90                         $doxygen_comments = 1;
  91                 } elsif ($x eq "splint") {
  92                         $splint_comments = 1;
  93                 } else {
  94                         print "cstyle: unrecognized construct \"$x\"\n";
  95                         print $usage;
  96                         exit 2;
  97                 }
  98         }
  99 }
 100 
 101 my ($filename, $line, $prev);           # shared globals
 102 
 103 my $fmt;
 104 my $hdr_comment_start;
 105 
 106 if ($verbose) {
 107         $fmt = "%s: %d: %s\n%s\n";
 108 } else {
 109         $fmt = "%s: %d: %s\n";
 110 }
 111 
 112 if ($doxygen_comments) {
 113         # doxygen comments look like "/*!" or "/**"; allow them.
 114         $hdr_comment_start = qr/^\s*\/\*[\!\*]?$/;
 115 } else {
 116         $hdr_comment_start = qr/^\s*\/\*$/;
 117 }
 118 
 119 # Note, following must be in single quotes so that \s and \w work right.
 120 my $typename = '(int|char|short|long|unsigned|float|double' .
 121     '|\w+_t|struct\s+\w+|union\s+\w+|FILE)';
 122 
 123 # mapping of old types to POSIX compatible types
 124 my %old2posix = (
 125         'unchar' => 'uchar_t',
 126         'ushort' => 'ushort_t',
 127         'uint' => 'uint_t',
 128         'ulong' => 'ulong_t',
 129         'u_int' => 'uint_t',
 130         'u_short' => 'ushort_t',
 131         'u_long' => 'ulong_t',
 132         'u_char' => 'uchar_t',
 133         'quad' => 'quad_t'
 134 );
 135 
 136 my $lint_re = qr/\/\*(?:
 137         ARGSUSED[0-9]*|NOTREACHED|LINTLIBRARY|VARARGS[0-9]*|
 138         CONSTCOND|CONSTANTCOND|CONSTANTCONDITION|EMPTY|
 139         FALLTHRU|FALLTHROUGH|LINTED.*?|PRINTFLIKE[0-9]*|
 140         PROTOLIB[0-9]*|SCANFLIKE[0-9]*|CSTYLED.*?
 141     )\*\//x;
 142 
 143 my $splint_re = qr/\/\*@.*?@\*\//x;
 144 
 145 my $warlock_re = qr/\/\*\s*(?:
 146         VARIABLES\ PROTECTED\ BY|
 147         MEMBERS\ PROTECTED\ BY|
 148         ALL\ MEMBERS\ PROTECTED\ BY|
 149         READ-ONLY\ VARIABLES:|
 150         READ-ONLY\ MEMBERS:|
 151         VARIABLES\ READABLE\ WITHOUT\ LOCK:|
 152         MEMBERS\ READABLE\ WITHOUT\ LOCK:|
 153         LOCKS\ COVERED\ BY|
 154         LOCK\ UNNEEDED\ BECAUSE|
 155         LOCK\ NEEDED:|
 156         LOCK\ HELD\ ON\ ENTRY:|
 157         READ\ LOCK\ HELD\ ON\ ENTRY:|
 158         WRITE\ LOCK\ HELD\ ON\ ENTRY:|
 159         LOCK\ ACQUIRED\ AS\ SIDE\ EFFECT:|
 160         READ\ LOCK\ ACQUIRED\ AS\ SIDE\ EFFECT:|
 161         WRITE\ LOCK\ ACQUIRED\ AS\ SIDE\ EFFECT:|
 162         LOCK\ RELEASED\ AS\ SIDE\ EFFECT:|
 163         LOCK\ UPGRADED\ AS\ SIDE\ EFFECT:|
 164         LOCK\ DOWNGRADED\ AS\ SIDE\ EFFECT:|
 165         FUNCTIONS\ CALLED\ THROUGH\ POINTER|
 166         FUNCTIONS\ CALLED\ THROUGH\ MEMBER|
 167         LOCK\ ORDER:
 168     )/x;
 169 
 170 my $err_stat = 0;               # exit status
 171 
 172 if ($#ARGV >= 0) {
 173         foreach my $arg (@ARGV) {
 174                 my $fh = new IO::File $arg, "r";
 175                 if (!defined($fh)) {
 176                         printf "%s: can not open\n", $arg;
 177                 } else {
 178                         &cstyle($arg, $fh);
 179                         close $fh;
 180                 }
 181         }
 182 } else {
 183         &cstyle("<stdin>", *STDIN);
 184 }
 185 exit $err_stat;
 186 
 187 my $no_errs = 0;                # set for CSTYLED-protected lines
 188 
 189 sub err($) {
 190         my ($error) = @_;
 191         unless ($no_errs) {
 192                 printf $fmt, $filename, $., $error, $line;
 193                 $err_stat = 1;
 194         }
 195 }
 196 
 197 sub err_prefix($$) {
 198         my ($prevline, $error) = @_;
 199         my $out = $prevline."\n".$line;
 200         unless ($no_errs) {
 201                 printf $fmt, $filename, $., $error, $out;
 202                 $err_stat = 1;
 203         }
 204 }
 205 
 206 sub err_prev($) {
 207         my ($error) = @_;
 208         unless ($no_errs) {
 209                 printf $fmt, $filename, $. - 1, $error, $prev;
 210                 $err_stat = 1;
 211         }
 212 }
 213 
 214 sub cstyle($$) {
 215 
 216 my ($fn, $filehandle) = @_;
 217 $filename = $fn;                        # share it globally
 218 
 219 my $in_cpp = 0;
 220 my $next_in_cpp = 0;
 221 
 222 my $in_comment = 0;
 223 my $in_header_comment = 0;
 224 my $comment_done = 0;
 225 my $in_warlock_comment = 0;
 226 my $in_function = 0;
 227 my $in_function_header = 0;
 228 my $in_declaration = 0;
 229 my $note_level = 0;
 230 my $nextok = 0;
 231 my $nocheck = 0;
 232 
 233 my $in_string = 0;
 234 
 235 my ($okmsg, $comment_prefix);
 236 
 237 $line = '';
 238 $prev = '';
 239 reset_indent();
 240 
 241 line: while (<$filehandle>) {
 242         s/\r?\n$//;     # strip return and newline
 243 
 244         # save the original line, then remove all text from within
 245         # double or single quotes, we do not want to check such text.
 246 
 247         $line = $_;
 248 
 249         #
 250         # C allows strings to be continued with a backslash at the end of
 251         # the line.  We translate that into a quoted string on the previous
 252         # line followed by an initial quote on the next line.
 253         #
 254         # (we assume that no-one will use backslash-continuation with character
 255         # constants)
 256         #
 257         $_ = '"' . $_           if ($in_string && !$nocheck && !$in_comment);
 258 
 259         #
 260         # normal strings and characters
 261         #
 262         s/'([^\\']|\\[^xX0]|\\0[0-9]*|\\[xX][0-9a-fA-F]*)'/''/g;
 263         s/"([^\\"]|\\.)*"/\"\"/g;
 264 
 265         #
 266         # detect string continuation
 267         #
 268         if ($nocheck || $in_comment) {
 269                 $in_string = 0;
 270         } else {
 271                 #
 272                 # Now that all full strings are replaced with "", we check
 273                 # for unfinished strings continuing onto the next line.
 274                 #
 275                 $in_string =
 276                     (s/([^"](?:"")*)"([^\\"]|\\.)*\\$/$1""/ ||
 277                     s/^("")*"([^\\"]|\\.)*\\$/""/);
 278         }
 279 
 280         #
 281         # figure out if we are in a cpp directive
 282         #
 283         $in_cpp = $next_in_cpp || /^\s*#/;      # continued or started
 284         $next_in_cpp = $in_cpp && /\\$/;        # only if continued
 285 
 286         # strip off trailing backslashes, which appear in long macros
 287         s/\s*\\$//;
 288 
 289         # an /* END CSTYLED */ comment ends a no-check block.
 290         if ($nocheck) {
 291                 if (/\/\* *END *CSTYLED *\*\//) {
 292                         $nocheck = 0;
 293                 } else {
 294                         reset_indent();
 295                         next line;
 296                 }
 297         }
 298 
 299         # a /*CSTYLED*/ comment indicates that the next line is ok.
 300         if ($nextok) {
 301                 if ($okmsg) {
 302                         err($okmsg);
 303                 }
 304                 $nextok = 0;
 305                 $okmsg = 0;
 306                 if (/\/\* *CSTYLED.*\*\//) {
 307                         /^.*\/\* *CSTYLED *(.*) *\*\/.*$/;
 308                         $okmsg = $1;
 309                         $nextok = 1;
 310                 }
 311                 $no_errs = 1;
 312         } elsif ($no_errs) {
 313                 $no_errs = 0;
 314         }
 315 
 316         # check length of line.
 317         # first, a quick check to see if there is any chance of being too long.
 318         if (($line =~ tr/\t/\t/) * 7 + length($line) > 80) {
 319                 # yes, there is a chance.
 320                 # replace tabs with spaces and check again.
 321                 my $eline = $line;
 322                 1 while $eline =~
 323                     s/\t+/' ' x (length($&) * 8 - length($`) % 8)/e;
 324                 if (length($eline) > 80) {
 325                         err("line > 80 characters");
 326                 }
 327         }
 328 
 329         # ignore NOTE(...) annotations (assumes NOTE is on lines by itself).
 330         if ($note_level || /\b_?NOTE\s*\(/) { # if in NOTE or this is NOTE
 331                 s/[^()]//g;                       # eliminate all non-parens
 332                 $note_level += s/\(//g - length;  # update paren nest level
 333                 next;
 334         }
 335 
 336         # a /* BEGIN CSTYLED */ comment starts a no-check block.
 337         if (/\/\* *BEGIN *CSTYLED *\*\//) {
 338                 $nocheck = 1;
 339         }
 340 
 341         # a /*CSTYLED*/ comment indicates that the next line is ok.
 342         if (/\/\* *CSTYLED.*\*\//) {
 343                 /^.*\/\* *CSTYLED *(.*) *\*\/.*$/;
 344                 $okmsg = $1;
 345                 $nextok = 1;
 346         }
 347         if (/\/\/ *CSTYLED/) {
 348                 /^.*\/\/ *CSTYLED *(.*)$/;
 349                 $okmsg = $1;
 350                 $nextok = 1;
 351         }
 352 
 353         # universal checks; apply to everything
 354         if (/\t +\t/) {
 355                 err("spaces between tabs");
 356         }
 357         if (/ \t+ /) {
 358                 err("tabs between spaces");
 359         }
 360         if (/\s$/) {
 361                 err("space or tab at end of line");
 362         }
 363         if (/[^ \t(]\/\*/ && !/\w\(\/\*.*\*\/\);/) {
 364                 err("comment preceded by non-blank");
 365         }
 366 
 367         # is this the beginning or ending of a function?
 368         # (not if "struct foo\n{\n")
 369         if (/^{$/ && $prev =~ /\)\s*(const\s*)?(\/\*.*\*\/\s*)?\\?$/) {
 370                 $in_function = 1;
 371                 $in_declaration = 1;
 372                 $in_function_header = 0;
 373                 $prev = $line;
 374                 next line;
 375         }
 376         if (/^}\s*(\/\*.*\*\/\s*)*$/) {
 377                 if ($prev =~ /^\s*return\s*;/) {
 378                         err_prev("unneeded return at end of function");
 379                 }
 380                 $in_function = 0;
 381                 reset_indent();         # we don't check between functions
 382                 $prev = $line;
 383                 next line;
 384         }
 385         if (/^\w*\($/) {
 386                 $in_function_header = 1;
 387         }
 388 
 389         if ($in_warlock_comment && /\*\//) {
 390                 $in_warlock_comment = 0;
 391                 $prev = $line;
 392                 next line;
 393         }
 394 
 395         # a blank line terminates the declarations within a function.
 396         # XXX - but still a problem in sub-blocks.
 397         if ($in_declaration && /^$/) {
 398                 $in_declaration = 0;
 399         }
 400 
 401         if ($comment_done) {
 402                 $in_comment = 0;
 403                 $in_header_comment = 0;
 404                 $comment_done = 0;
 405         }
 406         # does this looks like the start of a block comment?
 407         if (/$hdr_comment_start/) {
 408                 if (!/^\t*\/\*/) {
 409                         err("block comment not indented by tabs");
 410                 }
 411                 $in_comment = 1;
 412                 /^(\s*)\//;
 413                 $comment_prefix = $1;
 414                 if ($comment_prefix eq "") {
 415                         $in_header_comment = 1;
 416                 }
 417                 $prev = $line;
 418                 next line;
 419         }
 420         # are we still in the block comment?
 421         if ($in_comment) {
 422                 if (/^$comment_prefix \*\/$/) {
 423                         $comment_done = 1;
 424                 } elsif (/\*\//) {
 425                         $comment_done = 1;
 426                         err("improper block comment close")
 427                             unless ($ignore_hdr_comment && $in_header_comment);
 428                 } elsif (!/^$comment_prefix \*[ \t]/ &&
 429                     !/^$comment_prefix \*$/) {
 430                         err("improper block comment")
 431                             unless ($ignore_hdr_comment && $in_header_comment);
 432                 }
 433         }
 434 
 435         if ($in_header_comment && $ignore_hdr_comment) {
 436                 $prev = $line;
 437                 next line;
 438         }
 439 
 440         # check for errors that might occur in comments and in code.
 441 
 442         # allow spaces to be used to draw pictures in header comments.
 443         if (/[^ ]     / && !/".*     .*"/ && !$in_header_comment) {
 444                 err("spaces instead of tabs");
 445         }
 446         if (/^ / && !/^ \*[ \t\/]/ && !/^ \*$/ &&
 447             (!/^    \w/ || $in_function != 0)) {
 448                 err("indent by spaces instead of tabs");
 449         }
 450         if (/^\t+ [^ \t\*]/ || /^\t+  \S/ || /^\t+   \S/) {
 451                 err("continuation line not indented by 4 spaces");
 452         }
 453         if (/$warlock_re/ && !/\*\//) {
 454                 $in_warlock_comment = 1;
 455                 $prev = $line;
 456                 next line;
 457         }
 458         if (/^\s*\/\*./ && !/^\s*\/\*.*\*\// && !/$hdr_comment_start/) {
 459                 err("improper first line of block comment");
 460         }
 461 
 462         if ($in_comment) {      # still in comment, don't do further checks
 463                 $prev = $line;
 464                 next line;
 465         }
 466 
 467         if ((/[^(]\/\*\S/ || /^\/\*\S/) &&
 468             !(/$lint_re/ || ($splint_comments && /$splint_re/))) {
 469                 err("missing blank after open comment");
 470         }
 471         if (/\S\*\/[^)]|\S\*\/$/ &&
 472             !(/$lint_re/ || ($splint_comments && /$splint_re/))) {
 473                 err("missing blank before close comment");
 474         }
 475         if (/\/\/\S/) {         # C++ comments
 476                 err("missing blank after start comment");
 477         }
 478         # check for unterminated single line comments, but allow them when
 479         # they are used to comment out the argument list of a function
 480         # declaration.
 481         if (/\S.*\/\*/ && !/\S.*\/\*.*\*\// && !/\(\/\*/) {
 482                 err("unterminated single line comment");
 483         }
 484 
 485         # check that #if and #elif don't enumerate ISA defines when there
 486         # are more concise ways of checking.  E.g., don't do:
 487         #     #if defined(__amd64) || defined(__i386)
 488         # when there is:
 489         #     #ifdef __x86
 490         if ((/^(#if|#elif)\sdefined\((.*)\)\s\|\|\sdefined\((.*)\)/) ||
 491             (/^(#if|#elif)\s!defined\((.*)\)\s&&\s!defined\((.*)\)/)) {
 492                 my $directive = $1;
 493                 my $first = $2;
 494                 my $second = $3;
 495                 ($first, $second) = ($second, $first) if ($first gt $second);
 496 
 497                 if (($first eq "__amd64") && ($second eq "__i386")) {
 498                         err("$directive checking for $first or $second " .
 499                             "instead of __x86");
 500                 }
 501         }
 502 
 503         if (/^(#else|#endif|#include)(.*)$/) {
 504                 $prev = $line;
 505                 if ($picky) {
 506                         my $directive = $1;
 507                         my $clause = $2;
 508                         # Enforce ANSI rules for #else and #endif: no noncomment
 509                         # identifiers are allowed after #endif or #else.  Allow
 510                         # C++ comments since they seem to be a fact of life.
 511                         if ((($1 eq "#endif") || ($1 eq "#else")) &&
 512                             ($clause ne "") &&
 513                             (!($clause =~ /^\s+\/\*.*\*\/$/)) &&
 514                             (!($clause =~ /^\s+\/\/.*$/))) {
 515                                 err("non-comment text following " .
 516                                     "$directive (or malformed $directive " .
 517                                     "directive)");
 518                         }
 519                 }
 520                 next line;
 521         }
 522 
 523         #
 524         # delete any comments and check everything else.  Note that
 525         # ".*?" is a non-greedy match, so that we don't get confused by
 526         # multiple comments on the same line.
 527         #
 528         s/\/\*.*?\*\///g;
 529         s/\/\/.*$//;           # C++ comments
 530 
 531         # delete any trailing whitespace; we have already checked for that.
 532         s/\s*$//;
 533 
 534         # following checks do not apply to text in comments.
 535 
 536         if (/[^<>\s][!<>=]=/ || /[^<>][!<>=]=[^\s,]/ ||
 537             (/[^->]>[^,=>\s]/ && !/[^->]>$/) ||
 538             (/[^<]<[^,=<\s]/ && !/[^<]<$/) ||
 539             /[^<\s]<[^<]/ || /[^->\s]>[^>]/) {
 540                 err("missing space around relational operator");
 541         }
 542         if (/\S>>=/ || /\S<<=/ || />>=\S/ || /<<=\S/ || /\S[-+*\/&|^%]=/ ||
 543             (/[^-+*\/&|^%!<>=\s]=[^=]/ && !/[^-+*\/&|^%!<>=\s]=$/) ||
 544             (/[^!<>=]=[^=\s]/ && !/[^!<>=]=$/)) {
 545                 # XXX - should only check this for C++ code
 546                 # XXX - there are probably other forms that should be allowed
 547                 if (!/\soperator=/) {
 548                         err("missing space around assignment operator");
 549                 }
 550         }
 551         if (/[,;]\S/ && !/\bfor \(;;\)/) {
 552                 err("comma or semicolon followed by non-blank");
 553         }
 554         # allow "for" statements to have empty "while" clauses
 555         if (/\s[,;]/ && !/^[\t]+;$/ && !/^\s*for \([^;]*; ;[^;]*\)/) {
 556                 err("comma or semicolon preceded by blank");
 557         }
 558         if (/^\s*(&&|\|\|)/) {
 559                 err("improper boolean continuation");
 560         }
 561         if (/\S   *(&&|\|\|)/ || /(&&|\|\|)   *\S/) {
 562                 err("more than one space around boolean operator");
 563         }
 564         if (/\b(for|if|while|switch|sizeof|return|case)\(/) {
 565                 err("missing space between keyword and paren");
 566         }
 567         if (/(\b(for|if|while|switch|return)\b.*){2,}/ && !/^#define/) {
 568                 # multiple "case" and "sizeof" allowed
 569                 err("more than one keyword on line");
 570         }
 571         if (/\b(for|if|while|switch|sizeof|return|case)\s\s+\(/ &&
 572             !/^#if\s+\(/) {
 573                 err("extra space between keyword and paren");
 574         }
 575         # try to detect "func (x)" but not "if (x)" or
 576         # "#define foo (x)" or "int (*func)();"
 577         if (/\w\s\(/) {
 578                 my $s = $_;
 579                 # strip off all keywords on the line
 580                 s/\b(for|if|while|switch|return|case|sizeof)\s\(/XXX(/g;
 581                 s/#elif\s\(/XXX(/g;
 582                 s/^#define\s+\w+\s+\(/XXX(/;
 583                 # do not match things like "void (*f)();"
 584                 # or "typedef void (func_t)();"
 585                 s/\w\s\(+\*/XXX(*/g;
 586                 s/\b($typename|void)\s+\(+/XXX(/og;
 587                 if (/\w\s\(/) {
 588                         err("extra space between function name and left paren");
 589                 }
 590                 $_ = $s;
 591         }
 592         # try to detect "int foo(x)", but not "extern int foo(x);"
 593         # XXX - this still trips over too many legitimate things,
 594         # like "int foo(x,\n\ty);"
 595 #               if (/^(\w+(\s|\*)+)+\w+\(/ && !/\)[;,](\s|)*$/ &&
 596 #                   !/^(extern|static)\b/) {
 597 #                       err("return type of function not on separate line");
 598 #               }
 599         # this is a close approximation
 600         if (/^(\w+(\s|\*)+)+\w+\(.*\)(\s|)*$/ &&
 601             !/^(extern|static)\b/) {
 602                 err("return type of function not on separate line");
 603         }
 604         if (/^#define /) {
 605                 err("#define followed by space instead of tab");
 606         }
 607         if (/^\s*return\W[^;]*;/ && !/^\s*return\s*\(.*\);/) {
 608                 err("unparenthesized return expression");
 609         }
 610         if (/\bsizeof\b/ && !/\bsizeof\s*\(.*\)/) {
 611                 err("unparenthesized sizeof expression");
 612         }
 613         if (/\(\s/) {
 614                 err("whitespace after left paren");
 615         }
 616         # allow "for" statements to have empty "continue" clauses
 617         if (/\s\)/ && !/^\s*for \([^;]*;[^;]*; \)/) {
 618                 err("whitespace before right paren");
 619         }
 620         if (/^\s*\(void\)[^ ]/) {
 621                 err("missing space after (void) cast");
 622         }
 623         if (/\S{/ && !/{{/) {
 624                 err("missing space before left brace");
 625         }
 626         if ($in_function && /^\s+{/ &&
 627             ($prev =~ /\)\s*$/ || $prev =~ /\bstruct\s+\w+$/)) {
 628                 err("left brace starting a line");
 629         }
 630         if (/}(else|while)/) {
 631                 err("missing space after right brace");
 632         }
 633         if (/}\s\s+(else|while)/) {
 634                 err("extra space after right brace");
 635         }
 636         if (/\b_VOID\b|\bVOID\b|\bSTATIC\b/) {
 637                 err("obsolete use of VOID or STATIC");
 638         }
 639         if (/\b$typename\*/o) {
 640                 err("missing space between type name and *");
 641         }
 642         if (/^\s+#/) {
 643                 err("preprocessor statement not in column 1");
 644         }
 645         if (/^#\s/) {
 646                 err("blank after preprocessor #");
 647         }
 648         if (/!\s*(strcmp|strncmp|bcmp)\s*\(/) {
 649                 err("don't use boolean ! with comparison functions");
 650         }
 651 
 652         #
 653         # We completely ignore, for purposes of indentation:
 654         #  * lines outside of functions
 655         #  * preprocessor lines
 656         #
 657         if ($check_continuation && $in_function && !$in_cpp) {
 658                 process_indent($_);
 659         }
 660         if ($picky) {
 661                 # try to detect spaces after casts, but allow (e.g.)
 662                 # "sizeof (int) + 1", "void (*funcptr)(int) = foo;", and
 663                 # "int foo(int) __NORETURN;"
 664                 if ((/^\($typename( \*+)?\)\s/o ||
 665                     /\W\($typename( \*+)?\)\s/o) &&
 666                     !/sizeof\s*\($typename( \*)?\)\s/o &&
 667                     !/\($typename( \*+)?\)\s+=[^=]/o) {
 668                         err("space after cast");
 669                 }
 670                 if (/\b$typename\s*\*\s/o &&
 671                     !/\b$typename\s*\*\s+const\b/o) {
 672                         err("unary * followed by space");
 673                 }
 674         }
 675         if ($check_posix_types) {
 676                 # try to detect old non-POSIX types.
 677                 # POSIX requires all non-standard typedefs to end in _t,
 678                 # but historically these have been used.
 679                 if (/\b(unchar|ushort|uint|ulong|u_int|u_short|u_long|u_char|quad)\b/) {
 680                         err("non-POSIX typedef $1 used: use $old2posix{$1} instead");
 681                 }
 682         }
 683         if ($heuristic) {
 684                 # cannot check this everywhere due to "struct {\n...\n} foo;"
 685                 if ($in_function && !$in_declaration &&
 686                     /}./ && !/}\s+=/ && !/{.*}[;,]$/ && !/}(\s|)*$/ &&
 687                     !/} (else|while)/ && !/}}/) {
 688                         err("possible bad text following right brace");
 689                 }
 690                 # cannot check this because sub-blocks in
 691                 # the middle of code are ok
 692                 if ($in_function && /^\s+{/) {
 693                         err("possible left brace starting a line");
 694                 }
 695         }
 696         if (/^\s*else\W/) {
 697                 if ($prev =~ /^\s*}$/) {
 698                         err_prefix($prev,
 699                             "else and right brace should be on same line");
 700                 }
 701         }
 702         $prev = $line;
 703 }
 704 
 705 if ($prev eq "") {
 706         err("last line in file is blank");
 707 }
 708 
 709 }
 710 
 711 #
 712 # Continuation-line checking
 713 #
 714 # The rest of this file contains the code for the continuation checking
 715 # engine.  It's a pretty simple state machine which tracks the expression
 716 # depth (unmatched '('s and '['s).
 717 #
 718 # Keep in mind that the argument to process_indent() has already been heavily
 719 # processed; all comments have been replaced by control-A, and the contents of
 720 # strings and character constants have been elided.
 721 #
 722 
 723 my $cont_in;            # currently inside of a continuation
 724 my $cont_off;           # skipping an initializer or definition
 725 my $cont_noerr;         # suppress cascading errors
 726 my $cont_start;         # the line being continued
 727 my $cont_base;          # the base indentation
 728 my $cont_first;         # this is the first line of a statement
 729 my $cont_multiseg;      # this continuation has multiple segments
 730 
 731 my $cont_special;       # this is a C statement (if, for, etc.)
 732 my $cont_macro;         # this is a macro
 733 my $cont_case;          # this is a multi-line case
 734 
 735 my @cont_paren;         # the stack of unmatched ( and [s we've seen
 736 
 737 sub
 738 reset_indent()
 739 {
 740         $cont_in = 0;
 741         $cont_off = 0;
 742 }
 743 
 744 sub
 745 delabel($)
 746 {
 747         #
 748         # replace labels with tabs.  Note that there may be multiple
 749         # labels on a line.
 750         #
 751         local $_ = $_[0];
 752 
 753         while (/^(\t*)( *(?:(?:\w+\s*)|(?:case\b[^:]*)): *)(.*)$/) {
 754                 my ($pre_tabs, $label, $rest) = ($1, $2, $3);
 755                 $_ = $pre_tabs;
 756                 while ($label =~ s/^([^\t]*)(\t+)//) {
 757                         $_ .= "\t" x (length($2) + length($1) / 8);
 758                 }
 759                 $_ .= ("\t" x (length($label) / 8)).$rest;
 760         }
 761 
 762         return ($_);
 763 }
 764 
 765 sub
 766 process_indent($)
 767 {
 768         require strict;
 769         local $_ = $_[0];                       # preserve the global $_
 770 
 771         s///g; # No comments
 772         s/\s+$//;       # Strip trailing whitespace
 773 
 774         return                  if (/^$/);      # skip empty lines
 775 
 776         # regexps used below; keywords taking (), macros, and continued cases
 777         my $special = '(?:(?:\}\s*)?else\s+)?(?:if|for|while|switch)\b';
 778         my $macro = '[A-Z_][A-Z_0-9]*\(';
 779         my $case = 'case\b[^:]*$';
 780 
 781         # skip over enumerations, array definitions, initializers, etc.
 782         if ($cont_off <= 0 && !/^\s*$special/ &&
 783             (/(?:(?:\b(?:enum|struct|union)\s*[^\{]*)|(?:\s+=\s*)){/ ||
 784             (/^\s*{/ && $prev =~ /=\s*(?:\/\*.*\*\/\s*)*$/))) {
 785                 $cont_in = 0;
 786                 $cont_off = tr/{/{/ - tr/}/}/;
 787                 return;
 788         }
 789         if ($cont_off) {
 790                 $cont_off += tr/{/{/ - tr/}/}/;
 791                 return;
 792         }
 793 
 794         if (!$cont_in) {
 795                 $cont_start = $line;
 796 
 797                 if (/^\t* /) {
 798                         err("non-continuation indented 4 spaces");
 799                         $cont_noerr = 1;                # stop reporting
 800                 }
 801                 $_ = delabel($_);       # replace labels with tabs
 802 
 803                 # check if the statement is complete
 804                 return          if (/^\s*\}?$/);
 805                 return          if (/^\s*\}?\s*else\s*\{?$/);
 806                 return          if (/^\s*do\s*\{?$/);
 807                 return          if (/{$/);
 808                 return          if (/}[,;]?$/);
 809 
 810                 # Allow macros on their own lines
 811                 return          if (/^\s*[A-Z_][A-Z_0-9]*$/);
 812 
 813                 # cases we don't deal with, generally non-kosher
 814                 if (/{/) {
 815                         err("stuff after {");
 816                         return;
 817                 }
 818 
 819                 # Get the base line, and set up the state machine
 820                 /^(\t*)/;
 821                 $cont_base = $1;
 822                 $cont_in = 1;
 823                 @cont_paren = ();
 824                 $cont_first = 1;
 825                 $cont_multiseg = 0;
 826 
 827                 # certain things need special processing
 828                 $cont_special = /^\s*$special/? 1 : 0;
 829                 $cont_macro = /^\s*$macro/? 1 : 0;
 830                 $cont_case = /^\s*$case/? 1 : 0;
 831         } else {
 832                 $cont_first = 0;
 833 
 834                 # Strings may be pulled back to an earlier (half-)tabstop
 835                 unless ($cont_noerr || /^$cont_base    / ||
 836                     (/^\t*(?:    )?(?:gettext\()?\"/ && !/^$cont_base\t/)) {
 837                         err_prefix($cont_start,
 838                             "continuation should be indented 4 spaces");
 839                 }
 840         }
 841 
 842         my $rest = $_;                  # keeps the remainder of the line
 843 
 844         #
 845         # The split matches 0 characters, so that each 'special' character
 846         # is processed separately.  Parens and brackets are pushed and
 847         # popped off the @cont_paren stack.  For normal processing, we wait
 848         # until a ; or { terminates the statement.  "special" processing
 849         # (if/for/while/switch) is allowed to stop when the stack empties,
 850         # as is macro processing.  Case statements are terminated with a :
 851         # and an empty paren stack.
 852         #
 853         foreach $_ (split /[^\(\)\[\]\{\}\;\:]*/) {
 854                 next            if (length($_) == 0);
 855 
 856                 # rest contains the remainder of the line
 857                 my $rxp = "[^\Q$_\E]*\Q$_\E";
 858                 $rest =~ s/^$rxp//;
 859 
 860                 if (/\(/ || /\[/) {
 861                         push @cont_paren, $_;
 862                 } elsif (/\)/ || /\]/) {
 863                         my $cur = $_;
 864                         tr/\)\]/\(\[/;
 865 
 866                         my $old = (pop @cont_paren);
 867                         if (!defined($old)) {
 868                                 err("unexpected '$cur'");
 869                                 $cont_in = 0;
 870                                 last;
 871                         } elsif ($old ne $_) {
 872                                 err("'$cur' mismatched with '$old'");
 873                                 $cont_in = 0;
 874                                 last;
 875                         }
 876 
 877                         #
 878                         # If the stack is now empty, do special processing
 879                         # for if/for/while/switch and macro statements.
 880                         #
 881                         next            if (@cont_paren != 0);
 882                         if ($cont_special) {
 883                                 if ($rest =~ /^\s*{?$/) {
 884                                         $cont_in = 0;
 885                                         last;
 886                                 }
 887                                 if ($rest =~ /^\s*;$/) {
 888                                         err("empty if/for/while body ".
 889                                             "not on its own line");
 890                                         $cont_in = 0;
 891                                         last;
 892                                 }
 893                                 if (!$cont_first && $cont_multiseg == 1) {
 894                                         err_prefix($cont_start,
 895                                             "multiple statements continued ".
 896                                             "over multiple lines");
 897                                         $cont_multiseg = 2;
 898                                 } elsif ($cont_multiseg == 0) {
 899                                         $cont_multiseg = 1;
 900                                 }
 901                                 # We've finished this section, start
 902                                 # processing the next.
 903                                 goto section_ended;
 904                         }
 905                         if ($cont_macro) {
 906                                 if ($rest =~ /^$/) {
 907                                         $cont_in = 0;
 908                                         last;
 909                                 }
 910                         }
 911                 } elsif (/\;/) {
 912                         if ($cont_case) {
 913                                 err("unexpected ;");
 914                         } elsif (!$cont_special) {
 915                                 err("unexpected ;")     if (@cont_paren != 0);
 916                                 if (!$cont_first && $cont_multiseg == 1) {
 917                                         err_prefix($cont_start,
 918                                             "multiple statements continued ".
 919                                             "over multiple lines");
 920                                         $cont_multiseg = 2;
 921                                 } elsif ($cont_multiseg == 0) {
 922                                         $cont_multiseg = 1;
 923                                 }
 924                                 if ($rest =~ /^$/) {
 925                                         $cont_in = 0;
 926                                         last;
 927                                 }
 928                                 if ($rest =~ /^\s*special/) {
 929                                         err("if/for/while/switch not started ".
 930                                             "on its own line");
 931                                 }
 932                                 goto section_ended;
 933                         }
 934                 } elsif (/\{/) {
 935                         err("{ while in parens/brackets") if (@cont_paren != 0);
 936                         err("stuff after {")            if ($rest =~ /[^\s}]/);
 937                         $cont_in = 0;
 938                         last;
 939                 } elsif (/\}/) {
 940                         err("} while in parens/brackets") if (@cont_paren != 0);
 941                         if (!$cont_special && $rest !~ /^\s*(while|else)\b/) {
 942                                 if ($rest =~ /^$/) {
 943                                         err("unexpected }");
 944                                 } else {
 945                                         err("stuff after }");
 946                                 }
 947                                 $cont_in = 0;
 948                                 last;
 949                         }
 950                 } elsif (/\:/ && $cont_case && @cont_paren == 0) {
 951                         err("stuff after multi-line case") if ($rest !~ /$^/);
 952                         $cont_in = 0;
 953                         last;
 954                 }
 955                 next;
 956 section_ended:
 957                 # End of a statement or if/while/for loop.  Reset
 958                 # cont_special and cont_macro based on the rest of the
 959                 # line.
 960                 $cont_special = ($rest =~ /^\s*$special/)? 1 : 0;
 961                 $cont_macro = ($rest =~ /^\s*$macro/)? 1 : 0;
 962                 $cont_case = 0;
 963                 next;
 964         }
 965         $cont_noerr = 0                 if (!$cont_in);
 966 }