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 
  57 require 5.0;
  58 use IO::File;
  59 use Getopt::Std;
  60 use strict;
  61 
  62 my $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 
  76 my %opts;
  77 
  78 if (!getopts("cho:pvCP", \%opts)) {
  79         print $usage;
  80         exit 2;
  81 }
  82 
  83 my $check_continuation = $opts{'c'};
  84 my $heuristic = $opts{'h'};
  85 my $picky = $opts{'p'};
  86 my $verbose = $opts{'v'};
  87 my $ignore_hdr_comment = $opts{'C'};
  88 my $check_posix_types = $opts{'P'};
  89 
  90 my $doxygen_comments = 0;
  91 my $splint_comments = 0;
  92 
  93 if (defined($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 $usage;
 102                         exit 2;
 103                 }
 104         }
 105 }
 106 
 107 my ($filename, $line, $prev);           # shared globals
 108 
 109 my $fmt;
 110 my $hdr_comment_start;
 111 
 112 if ($verbose) {
 113         $fmt = "%s: %d: %s\n%s\n";
 114 } else {
 115         $fmt = "%s: %d: %s\n";
 116 }
 117 
 118 if ($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.
 133 my $fbsd_comment_start = qr/^\s*\/\*-$/;
 134 
 135 # Note, following must be in single quotes so that \s and \w work right.
 136 my $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
 140 my %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 
 157 my $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 
 164 my $splint_re = qr/\/\*@.*?@\*\//x;
 165 
 166 my $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 
 191 my $err_stat = 0;               # exit status
 192 
 193 if ($#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 }
 206 exit $err_stat;
 207 
 208 my $no_errs = 0;                # set for CSTYLED-protected lines
 209 
 210 sub err($) {
 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 
 222 sub err_prefix($$) {
 223         my ($prevline, $error) = @_;
 224         my $out = $prevline."\n".$line;
 225         unless ($no_errs) {
 226                 if ($verbose) {
 227                         printf $fmt, $filename, $., $error, $out;
 228                 } else {
 229                         printf $fmt, $filename, $., $error;
 230                 }
 231                 $err_stat = 1;
 232         }
 233 }
 234 
 235 sub err_prev($) {
 236         my ($error) = @_;
 237         unless ($no_errs) {
 238                 if ($verbose) {
 239                         printf $fmt, $filename, $. - 1, $error, $prev;
 240                 } else {
 241                         printf $fmt, $filename, $. - 1, $error;
 242                 }
 243                 $err_stat = 1;
 244         }
 245 }
 246 
 247 sub cstyle($$) {
 248 
 249 my ($fn, $filehandle) = @_;
 250 $filename = $fn;                        # share it globally
 251 
 252 my $in_cpp = 0;
 253 my $next_in_cpp = 0;
 254 
 255 my $in_comment = 0;
 256 my $in_header_comment = 0;
 257 my $comment_done = 0;
 258 my $in_warlock_comment = 0;
 259 my $in_function = 0;
 260 my $in_function_header = 0;
 261 my $function_header_full_indent = 0;
 262 my $in_declaration = 0;
 263 my $note_level = 0;
 264 my $nextok = 0;
 265 my $nocheck = 0;
 266 
 267 my $in_string = 0;
 268 
 269 my ($okmsg, $comment_prefix);
 270 
 271 $line = '';
 272 $prev = '';
 273 reset_indent();
 274 
 275 line: while (<$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 = $line;
 759 }
 760 
 761 if ($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 
 779 my $cont_in;            # currently inside of a continuation
 780 my $cont_off;           # skipping an initializer or definition
 781 my $cont_noerr;         # suppress cascading errors
 782 my $cont_start;         # the line being continued
 783 my $cont_base;          # the base indentation
 784 my $cont_first;         # this is the first line of a statement
 785 my $cont_multiseg;      # this continuation has multiple segments
 786 
 787 my $cont_special;       # this is a C statement (if, for, etc.)
 788 my $cont_macro;         # this is a macro
 789 my $cont_case;          # this is a multi-line case
 790 
 791 my @cont_paren;         # the stack of unmatched ( and [s we've seen
 792 
 793 sub
 794 reset_indent()
 795 {
 796         $cont_in = 0;
 797         $cont_off = 0;
 798 }
 799 
 800 sub
 801 delabel($)
 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 
 821 sub
 822 process_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;
1012 section_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 }