add a trivial patch style checker

We are seeing increasing levels of minor patch style violations in submissions
to the mailing lists as well as making it into the tree.  These detract from
the quality of the submission and cause unnessary work for reviewers.

As a first step package up the current state of the patch style checker and
include it in the kernel tree.  Add instructions suggesting running it on
submissions.  This adds version v0.01 of the checkpatch.pl script.

Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Joel Schopp <jschopp@austin.ibm.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 595 insertions, 0 deletions

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
new file mode 100644
index 000000000000..e216d49624b7
--- /dev/null
+++ b/scripts/checkpatch.pl
@@ -0,0 +1,595 @@
+#!/usr/bin/perl -w
+# (c) 2001, Dave Jones. <davej@codemonkey.org.uk> (the file handling bit)
+# (c) 2005, Joel Scohpp <jschopp@austin.ibm.com> (the ugly bit)
+# (c) 2007, Andy Whitcroft <apw@uk.ibm.com> (new conditions, test suite, etc)
+# Licensed under the terms of the GNU GPL License version 2
+
+use strict;
+
+my $P = $0;
+
+my $V = '0.01';
+
+use Getopt::Long qw(:config no_auto_abbrev);
+
+my $quiet = 0;
+my $tree = 1;
+my $chk_signoff = 1;
+my $chk_patch = 1;
+GetOptions(
+	'q|quiet'	=> \$quiet,
+	'tree!'		=> \$tree,
+	'signoff!'	=> \$chk_signoff,
+	'patch!'	=> \$chk_patch,
+) or exit;
+
+my $exit = 0;
+
+if ($#ARGV < 0) {
+	print "usage: patchstylecheckemail.pl [options] patchfile\n";
+	print "version: $V\n";
+	print "options: -q           => quiet\n";
+	print "         --no-tree    => run without a kernel tree\n";
+	exit(1);
+}
+
+if ($tree && !top_of_kernel_tree()) {
+	print "Must be run from the top-level dir. of a kernel tree\n";
+	exit(2);
+}
+
+my @deprecated = ();
+my $removal = 'Documentation/feature-removal-schedule.txt';
+if ($tree && -f $removal) {
+	open(REMOVE, "<$removal") || die "$P: $removal: open failed - $!\n";
+	while (<REMOVE>) {
+		if (/^Files:\s+(.*\S)/) {
+			for my $file (split(/[, ]+/, $1)) {
+				if ($file =~ m@include/(.*)@) {
+					push(@deprecated, $1);
+				}
+			}
+		}
+	}
+}
+
+my @lines = ();
+while (<>) {
+	chomp;
+	push(@lines, $_);
+	if (eof(ARGV)) {
+		if (!process($ARGV, @lines)) {
+			$exit = 1;
+		}
+		@lines = ();
+	}
+}
+
+exit($exit);
+
+sub top_of_kernel_tree {
+	if ((-f "COPYING") && (-f "CREDITS") && (-f "Kbuild") &&
+	    (-f "MAINTAINERS") && (-f "Makefile") && (-f "README") &&
+	    (-d "Documentation") && (-d "arch") && (-d "include") &&
+	    (-d "drivers") && (-d "fs") && (-d "init") && (-d "ipc") &&
+	    (-d "kernel") && (-d "lib") && (-d "scripts")) {
+		return 1;
+	}
+	return 0;
+}
+
+sub expand_tabs {
+	my ($str) = @_;
+
+	my $res = '';
+	my $n = 0;
+	for my $c (split(//, $str)) {
+		if ($c eq "\t") {
+			$res .= ' ';
+			$n++;
+			for (; ($n % 8) != 0; $n++) {
+				$res .= ' ';
+			}
+			next;
+		}
+		$res .= $c;
+		$n++;
+	}
+
+	return $res;
+}
+
+sub cat_vet {
+	my ($vet) = @_;
+
+	$vet =~ s/\t/^I/;
+	$vet =~ s/$/\$/;
+
+	return $vet;
+}
+
+sub process {
+	my $filename = shift;
+	my @lines = @_;
+
+	my $linenr=0;
+	my $prevline="";
+	my $stashline="";
+
+	my $lineforcounting='';
+	my $indent;
+	my $previndent=0;
+	my $stashindent=0;
+
+	my $clean = 1;
+	my $signoff = 0;
+	my $is_patch = 0;
+
+	# Trace the real file/line as we go.
+	my $realfile = '';
+	my $realline = 0;
+	my $realcnt = 0;
+	my $here = '';
+	my $in_comment = 0;
+	my $first_line = 0;
+
+	foreach my $line (@lines) {
+		$linenr++;
+
+#extract the filename as it passes
+		if ($line=~/^\+\+\+\s+(\S+)/) {
+			$realfile=$1;
+			$in_comment = 0;
+			next;
+		}
+#extract the line range in the file after the patch is applied
+		if ($line=~/^\@\@ -\d+,\d+ \+(\d+)(,(\d+))? \@\@/) {
+			$is_patch = 1;
+			$first_line = 1;
+			$in_comment = 0;
+			$realline=$1-1;
+			if (defined $2) {
+				$realcnt=$3+1;
+			} else {
+				$realcnt=1+1;
+			}
+			next;
+		}
+
+#track the line number as we move through the hunk
+		if ($line=~/^[ \+]/) {
+			$realline++;
+			$realcnt-- if ($realcnt != 0);
+
+			# track any sort of multi-line comment.  Obviously if
+			# the added text or context do not include the whole
+			# comment we will not see it. Such is life.
+			#
+			# Guestimate if this is a continuing comment.  If this
+			# is the start of a diff block and this line starts
+			# ' *' then it is very likely a comment.
+			if ($first_line and $line =~ m@^.\s*\*@) {
+				$in_comment = 1;
+			}
+			if ($line =~ m@/\*@) {
+				$in_comment = 1;
+			}
+			if ($line =~ m@\*/@) {
+				$in_comment = 0;
+			}
+
+			$lineforcounting = $line;
+			$lineforcounting =~ s/^\+//;
+			$lineforcounting = expand_tabs($lineforcounting);
+
+			my ($white) = ($lineforcounting =~ /^(\s*)/);
+			$indent = length($white);
+
+			# Track the previous line.
+			($prevline, $stashline) = ($stashline, $line);
+			($previndent, $stashindent) = ($stashindent, $indent);
+			$first_line = 0;
+		}
+
+#make up the handle for any error we report on this line
+		$here = "PATCH: $ARGV:$linenr:";
+		$here .= "\nFILE: $realfile:$realline:" if ($realcnt != 0);
+
+		my $herecurr = "$here\n$line\n\n";
+		my $hereprev = "$here\n$prevline\n$line\n\n";
+
+#check the patch for a signoff:
+		if ($line =~ /^\s*Signed-off-by:\s/) {
+			$signoff++;
+
+		} elsif ($line =~ /^\s*signed-off-by:/i) {
+			if (!($line =~ /^\s*Signed-off-by:/)) {
+				print "use Signed-off-by:\n";
+				print "$herecurr";
+				$clean = 0;
+			}
+			if ($line =~ /^\s*signed-off-by:\S/i) {
+				print "need space after Signed-off-by:\n";
+				print "$herecurr";
+				$clean = 0;
+			}
+		}
+
+#ignore lines not being added
+		if ($line=~/^[^\+]/) {next;}
+
+# check we are in a valid source file *.[hcsS] if not then ignore this hunk
+		next if ($realfile !~ /\.[hcsS]$/);
+
+#trailing whitespace
+		if ($line=~/\S\s+$/) {
+			my $herevet = "$here\n" . cat_vet($line) . "\n\n";
+			print "trailing whitespace\n";
+			print "$herevet";
+			$clean = 0;
+		}
+#80 column limit
+		if (!($prevline=~/\/\*\*/) && length($lineforcounting) > 80) {
+			print "line over 80 characters\n";
+			print "$herecurr";
+			$clean = 0;
+		}
+
+# check we are in a valid source file *.[hc] if not then ignore this hunk
+		next if ($realfile !~ /\.[hc]$/);
+
+# at the beginning of a line any tabs must come first and anything
+# more than 8 must use tabs.
+		if ($line=~/^\+\s* \t\s*\S/ or $line=~/^\+\s*        \s*/) {
+			my $herevet = "$here\n" . cat_vet($line) . "\n\n";
+			print "use tabs not spaces\n";
+			print "$herevet";
+			$clean = 0;
+		}
+
+		#
+		# The rest of our checks refer specifically to C style
+		# only apply those _outside_ comments.
+		#
+		next if ($in_comment);
+
+# no C99 // comments
+		if ($line =~ m@//@ and !($line =~ m@\".*//.*\"@)) {
+			print "do not use C99 // comments\n";
+			print "$herecurr";
+			$clean = 0;
+		}
+
+		# Remove comments from the line before processing.
+		$line =~ s@/\*.*\*/@@g;
+		$line =~ s@/\*.*@@;
+		$line =~ s@.*\*/@@;
+		$line =~ s@//.*@@;
+
+#EXPORT_SYMBOL should immediately follow its function closing }.
+		if (($line =~ /EXPORT_SYMBOL.*\(.*\)/) ||
+		    ($line =~ /EXPORT_UNUSED_SYMBOL.*\(.*\)/)) {
+			if (($prevline !~ /^}/) &&
+			   ($prevline !~ /^\+}/) &&
+			   ($prevline !~ /^ }/)) {
+				print "EXPORT_SYMBOL(func); should immediately follow its function\n";
+				print "$herecurr";
+				$clean = 0;
+			}
+		}
+
+		# check for static initialisers.
+		if ($line=~/\s*static\s.*=\s+(0|NULL);/) {
+			print "do not initialise statics to 0 or NULL\n";
+			print "$herecurr";
+			$clean = 0;
+		}
+
+		# check for new typedefs.
+		if ($line=~/\s*typedef\s/) {
+			print "do not add new typedefs\n";
+			print "$herecurr";
+			$clean = 0;
+		}
+
+# * goes on variable not on type
+		if ($line=~/[A-Za-z\d_]+\* [A-Za-z\d_]+/) {
+			print "\"foo* bar\" should be \"foo *bar\"\n";
+			print "$herecurr";
+			$clean = 0;
+		}
+
+# # no BUG() or BUG_ON()
+# 		if ($line =~ /\b(BUG|BUG_ON)\b/) {
+# 			print "Try to use WARN_ON & Recovery code rather than BUG() or BUG_ON()\n";
+# 			print "$herecurr";
+# 			$clean = 0;
+# 		}
+
+# printk should use KERN_* levels
+		if ($line =~ /\bprintk\((?!KERN_)/) {
+			print "printk() should include KERN_ facility level\n";
+			print "$herecurr";
+			$clean = 0;
+		}
+
+#function brace can't be on same line, except for #defines of do while, or if closed on same line
+		if (($line=~/[A-Za-z\d_]+\**\s+\**[A-Za-z\d_]+\(.*\).* {/) and
+		    !($line=~/\#define.*do\s{/) and !($line=~/}/)) {
+			print "braces following function declarations go on the next line\n";
+			print "$herecurr";
+			$clean = 0;
+		}
+		my $opline = $line;
+		$opline =~ s/^.//;
+		if (!($line=~/\#\s*include/)) {
+			# Check operator spacing.
+			my @elements = split(/(<<=|>>=|<=|>=|==|!=|\+=|-=|\*=|\/=|%=|\^=|\|=|&=|->|<<|>>|<|>|=|!|~|&&|\|\||,|\^|\+\+|--|;|&|\||\+|-|\*|\/\/|\/)/, $opline);
+			for (my $n = 0; $n < $#elements; $n += 2) {
+				# $wN says we have white-space before or after
+				# $sN says we have a separator before or after
+				# $oN says we have another operator before or after
+				my $w1 = $elements[$n] =~ /\s$/;
+				my $s1 = $elements[$n] =~ /(\[|\(|\s)$/;
+				my $o1 = $elements[$n] eq '';
+				my $op = $elements[$n + 1];
+				my $w2 = 1;
+				my $s2 = 1;
+				my $o2 = 0;
+				# If we have something after the operator handle it.
+				if (defined $elements[$n + 2]) {
+					$w2 = $elements[$n + 2] =~ /^\s/;
+					$s2 = $elements[$n + 2] =~ /^(\s|\)|\]|;)/;
+					$o2 = $elements[$n + 2] eq '';
+				}
+
+				# Generate the context.
+				my $at = "here: ";
+				for (my $m = $n; $m >= 0; $m--) {
+					if ($elements[$m] ne '') {
+						$at .= $elements[$m];
+						last;
+					}
+				}
+				$at .= $op;
+				for (my $m = $n + 2; defined $elements[$m]; $m++) {
+					if ($elements[$m] ne '') {
+						$at .= $elements[$m];
+						last;
+					}
+				}
+
+				##print "<$s1:$op:$s2> <$elements[$n]:$elements[$n + 1]:$elements[$n + 2]>\n";
+				# Skip things apparently in quotes.
+				next if ($line=~/\".*\Q$op\E.*\"/ or $line=~/\'\Q$op\E\'/);
+
+				# We need ; as an operator.  // is a comment.
+				if ($op eq ';' or $op eq '//') {
+
+				# -> should have no spaces
+				} elsif ($op eq '->') {
+					if ($s1 or $s2) {
+						print "no spaces around that '$op' $at\n";
+						print "$herecurr";
+						$clean = 0;
+					}
+
+				# , must have a space on the right.
+				} elsif ($op eq ',') {
+					if (!$s2) {
+						print "need space after that '$op' $at\n";
+						print "$herecurr";
+						$clean = 0;
+					}
+
+				# unary ! and unary ~ are allowed no space on the right
+				} elsif ($op eq '!' or $op eq '~') {
+					if (!$s1 && !$o1) {
+						print "need space before that '$op' $at\n";
+						print "$herecurr";
+						$clean = 0;
+					}
+					if ($s2) {
+						print "no space after that '$op' $at\n";
+						print "$herecurr";
+						$clean = 0;
+					}
+
+				# unary ++ and unary -- are allowed no space on one side.
+				} elsif ($op eq '++' or $op eq '--') {
+					if (($s1 && $s2) || ((!$s1 && !$o1) && (!$s2 && !$o2))) {
+						print "need space one side of that '$op' $at\n";
+						print "$herecurr";
+						$clean = 0;
+					}
+
+				# & is both unary and binary
+				# unary:
+				# 	a &b
+				# binary (consistent spacing):
+				#	a&b		OK
+				#	a & b		OK
+				#
+				# boiling down to: if there is a space on the right then there
+				# should be one on the left.
+				#
+				# - is the same
+				#
+				# * is the same only adding:
+				# type:
+				# 	(foo *)
+				#	(foo **)
+				#
+				} elsif ($op eq '&' or $op eq '-' or $op eq '*') {
+					if ($w2 and !$w1) {
+						print "need space before that '$op' $at\n";
+						print "$herecurr";
+						$clean = 0;
+					}
+
+				# << and >> may either have or not have spaces both sides
+				} elsif ($op eq '<<' or $op eq '>>' or $op eq '+' or $op eq '/' or
+					 $op eq '^' or $op eq '|')
+				{
+					if ($s1 != $s2) {
+						print "need consistent spacing around '$op' $at\n";
+						print "$herecurr";
+						$clean = 0;
+					}
+
+				# All the others need spaces both sides.
+				} elsif (!$s1 or !$s2) {
+					print "need spaces around that '$op' $at\n";
+					print "$herecurr";
+					$clean = 0;
+				}
+			}
+		}
+
+#need space before brace following if, while, etc
+		if ($line=~/\(.*\){/) {
+			print "need a space before the brace\n";
+			print "$herecurr";
+			$clean = 0;
+		}
+
+#goto labels aren't indented, allow a single space however
+		if ($line=~/^.\s+[A-Za-z\d_]+:/ and
+		   !($line=~/^. [A-Za-z\d_]+:/) and !($line=~/^.\s+default:/)) {
+			print "labels should not be indented\n";
+			print "$herecurr";
+			$clean = 0;
+		}
+
+# Need a space before open parenthesis after if, while etc
+		if ($line=~/(if|while|for|switch)\(/) {
+			print "need a space before the open parenthesis\n";
+			print "$herecurr";
+			$clean = 0;
+		}
+
+# Check for illegal assignment in if conditional.
+		if ($line=~/(if|while)\s*\(.*[^<>!=]=[^=].*\)/) {
+			print "do not use assignment in if condition\n";
+			print "$herecurr";
+			$clean = 0;
+		}
+
+		# Check for }<nl>else {, these must be at the same
+		# indent level to be relevant to each other.
+		if ($prevline=~/}\s*$/ and $line=~/^.\s*else\s*/ and
+						$previndent == $indent) {
+			print "else should follow close brace\n";
+			print "$hereprev";
+			$clean = 0;
+		}
+
+		# Check for switch () {<nl>case, these must be at the
+		# same indent.  We will only catch the first one, as our
+		# context is very small but people tend to be consistent
+		# so we will catch them out more often than not.
+		if ($prevline=~/\s*switch\s*\(.*\)/ and $line=~/\s*case\s+/
+						and $previndent != $indent) {
+			print "switch and case should be at the same indent\n";
+			print "$hereprev";
+			$clean = 0;
+		}
+
+#studly caps, commented out until figure out how to distinguish between use of existing and adding new
+#		if (($line=~/[\w_][a-z\d]+[A-Z]/) and !($line=~/print/)) {
+#		    print "No studly caps, use _\n";
+#		    print "$herecurr";
+#		    $clean = 0;
+#		}
+
+#no spaces allowed after \ in define
+		if ($line=~/\#define.*\\\s$/) {
+			print("Whitepspace after \\ makes next lines useless\n");
+			print "$herecurr";
+			$clean = 0;
+		}
+
+#warn if <asm/foo.h> is #included and <linux/foo.h> is available.
+		if ($tree && $line =~ qr|\s*\#\s*include\s*\<asm\/(.*)\.h\>|) {
+			my $checkfile = "include/linux/$1.h";
+			if (-f $checkfile) {
+				print "Use #include <linux/$1.h> instead of <asm/$1.h>\n";
+				print $herecurr;
+				$clean = 0;
+			}
+		}
+
+#if/while/etc brace do not go on next line, unless #defining a do while loop, or if that brace on the next line is for something else
+		if ($prevline=~/(if|while|for|switch)\s*\(/) {
+			my @opened = $prevline=~/\(/g;
+			my @closed = $prevline=~/\)/g;
+			my $nr_line = $linenr;
+			my $remaining = $realcnt;
+			my $next_line = $line;
+			my $extra_lines = 0;
+			my $display_segment = $prevline;
+
+			while ($remaining > 0 && scalar @opened > scalar @closed) {
+				$prevline .= $next_line;
+				$display_segment .= "\n" . $next_line;
+				$next_line = $lines[$nr_line];
+				$nr_line++;
+				$remaining--;
+
+				@opened = $prevline=~/\(/g;
+				@closed = $prevline=~/\)/g;
+			}
+
+			if (($prevline=~/(if|while|for|switch)\s*\(.*\)\s*$/) and ($next_line=~/{/) and
+			   !($next_line=~/(if|while|for)/) and !($next_line=~/\#define.*do.*while/)) {
+				print "That { should be on the previous line\n";
+				print "$display_segment\n$next_line\n\n";
+				$clean = 0;
+			}
+		}
+
+#multiline macros should be enclosed in a do while loop
+		if (($prevline=~/\#define.*\\/) and !($prevline=~/do\s+{/) and
+		   !($prevline=~/\(\{/) and ($line=~/;\s*\\/) and
+		   !($line=~/do.*{/) and !($line=~/\(\{/)) {
+			print "Macros with multiple statements should be enclosed in a do - while loop\n";
+			print "$hereprev";
+			$clean = 0;
+		}
+
+# don't include deprecated include files
+		for my $inc (@deprecated) {
+			if ($line =~ m@\#\s*include\s*\<$inc>@) {
+				print "Don't use <$inc>: see Documentation/feature-removal-schedule.txt\n";
+				print "$herecurr";
+				$clean = 0;
+			}
+		}
+
+# don't use kernel_thread()
+		if ($line =~ /\bkernel_thread\b/) {
+			print "Don't use kernel_thread(), use kthread(): see Documentation/feature-removal-schedule.txt\n";
+			print "$herecurr";
+			$clean = 0;
+		}
+	}
+
+	if ($chk_patch && !$is_patch) {
+		$clean = 0;
+		print "Does not appear to be a unified-diff format patch\n";
+	}
+	if ($is_patch && $chk_signoff && $signoff == 0) {
+		$clean = 0;
+		print "Missing Signed-off-by: line(s)\n";
+	}
+
+	if ($clean == 1 && $quiet == 0) {
+		print "Your patch has no obvious style problems and is ready for submission.\n"
+	}
+	if ($clean == 0 && $quiet == 0) {
+		print "Your patch has style problems, please review.  If any of these errors\n";
+		print "are false positives report them to the maintainer, see\n";
+		print "CHECKPATCH in MAINTAINERS.\n";
+	}
+	return $clean;
+}