checkpatch: validate signature styles and To: and Cc: lines

Signatures have many forms and can sometimes cause problems if not in the
correct format when using git send-email or quilt.

Try to verify the signature tags and email addresses to use the generally
accepted "Signed-off-by: Full Name <email@domain.tld>" form.

Original idea by Anish Kumar <anish198519851985@gmail.com>

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Anish Kumar <anish198519851985@gmail.com>
Cc: Nick Bowler <nbowler@elliptictech.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 115 insertions, 8 deletions

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 63cca81b1105..b14f830cb0fa 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -217,6 +217,16 @@ our $logFunctions = qr{(?x:
         MODULE_[A-Z_]+
 )};
 
+our $signature_tags = qr{(?xi:
+        Signed-off-by:|
+        Acked-by:|
+        Tested-by:|
+        Reviewed-by:|
+        Reported-by:|
+        To:|
+        Cc:
+)};
+
 our @typeList = (
         qr{void},
         qr{(?:unsigned\s+)?char},
@@ -356,6 +366,76 @@ sub top_of_kernel_tree {
         return 1;
 }
 
+sub parse_email {
+        my ($formatted_email) = @_;
+
+        my $name = "";
+        my $address = "";
+        my $comment = "";
+
+        if ($formatted_email =~ /^(.*)<(\S+\@\S+)>(.*)$/) {
+                $name = $1;
+                $address = $2;
+                $comment = $3 if defined $3;
+        } elsif ($formatted_email =~ /^\s*<(\S+\@\S+)>(.*)$/) {
+                $address = $1;
+                $comment = $2 if defined $2;
+        } elsif ($formatted_email =~ /(\S+\@\S+)(.*)$/) {
+                $address = $1;
+                $comment = $2 if defined $2;
+                $formatted_email =~ s/$address.*$//;
+                $name = $formatted_email;
+                $name =~ s/^\s+|\s+$//g;
+                $name =~ s/^\"|\"$//g;
+                # If there's a name left after stripping spaces and
+                # leading quotes, and the address doesn't have both
+                # leading and trailing angle brackets, the address
+                # is invalid. ie:
+                #   "joe smith joe@smith.com" bad
+                #   "joe smith <joe@smith.com" bad
+                if ($name ne "" && $address !~ /^<[^>]+>$/) {
+                        $name = "";
+                        $address = "";
+                        $comment = "";
+                }
+        }
+
+        $name =~ s/^\s+|\s+$//g;
+        $name =~ s/^\"|\"$//g;
+        $address =~ s/^\s+|\s+$//g;
+        $address =~ s/^\<|\>$//g;
+
+        if ($name =~ /[^\w \-]/i) { ##has "must quote" chars
+                $name =~ s/(?<!\\)"/\\"/g; ##escape quotes
+                $name = "\"$name\"";
+        }
+
+        return ($name, $address, $comment);
+}
+
+sub format_email {
+        my ($name, $address) = @_;
+
+        my $formatted_email;
+
+        $name =~ s/^\s+|\s+$//g;
+        $name =~ s/^\"|\"$//g;
+        $address =~ s/^\s+|\s+$//g;
+
+        if ($name =~ /[^\w \-]/i) { ##has "must quote" chars
+                $name =~ s/(?<!\\)"/\\"/g; ##escape quotes
+                $name = "\"$name\"";
+        }
+
+        if ("$name" eq "") {
+                $formatted_email = "$address";
+        } else {
+                $formatted_email = "$name <$address>";
+        }
+
+        return $formatted_email;
+}
+
 sub expand_tabs {
         my ($str) = @_;
 
@@ -1380,17 +1460,44 @@ sub process {
                         }
                 }
 
-#check the patch for a signoff:
+# Check the patch for a signoff:
                 if ($line =~ /^\s*signed-off-by:/i) {
-                        # This is a signoff, if ugly, so do not double report.
                         $signoff++;
-                        if (!($line =~ /^\s*Signed-off-by:/)) {
-                                WARN("Signed-off-by: is the preferred form\n" .
-                                        $herecurr);
+                }
+
+# Check signature styles
+                if ($line =~ /^(\s*)($signature_tags)(\s*)(.*)/) {
+                        my $space_before = $1;
+                        my $sign_off = $2;
+                        my $space_after = $3;
+                        my $email = $4;
+                        my $ucfirst_sign_off = ucfirst(lc($sign_off));
+
+                        if (defined $space_before && $space_before ne "") {
+                                WARN("Do not use whitespace before $ucfirst_sign_off\n" . $herecurr);
                         }
-                        if ($line =~ /^\s*signed-off-by:\S/i) {
-                                WARN("space required after Signed-off-by:\n" .
-                                        $herecurr);
+                        if ($sign_off =~ /-by:$/i && $sign_off ne $ucfirst_sign_off) {
+                                WARN("'$ucfirst_sign_off' is the preferred signature form\n" . $herecurr);
+                        }
+                        if (!defined $space_after || $space_after ne " ") {
+                                WARN("Use a single space after $ucfirst_sign_off\n" . $herecurr);
+                        }
+
+                        my ($email_name, $email_address, $comment) = parse_email($email);
+                        my $suggested_email = format_email(($email_name, $email_address));
+                        if ($suggested_email eq "") {
+                                ERROR("Unrecognized email address: '$email'\n" . $herecurr);
+                        } else {
+                                my $dequoted = $suggested_email;
+                                $dequoted =~ s/^"//;
+                                $dequoted =~ s/" </ </;
+                                # Don't force email to have quotes
+                                # Allow just an angle bracketed address
+                                if ("$dequoted$comment" ne $email &&
+                                    "<$email_address>$comment" ne $email &&
+                                    "$suggested_email$comment" ne $email) {
+                                        WARN("email address '$email' might be better as '$suggested_email$comment'\n" . $herecurr);
+                                }
                         }
                 }