checksrc: taught to skip comments

... but output non-stripped version of the line, even if that then can
make the script identify the wrong position in the line at
times. Showing the line stripped (ie without comments) is just too
surprising.

lib/checksrc.pl

@@ -54,7 +54,8 @@ my %warnings = (
     'INDENTATION'      => 'wrong start column for code',
     'COPYRIGHT'        => 'file missing a copyright statement',
     'BADCOMMAND'       => 'bad !checksrc! instruction',
-    'UNUSEDIGNORE'     => 'a warning ignore was not used'
+    'UNUSEDIGNORE'     => 'a warning ignore was not used',
+    'OPENCOMMENT'      => 'file ended with a /* comment still "open"'
     );
 
 sub readwhitelist {
@@ -248,12 +249,14 @@ sub scanfile {
     my $l;
     open(R, "<$file") || die "failed to open $file";
 
+    my $incomment=0;
     my $copyright=0;
     checksrc_clear(); # for file based ignores
 
     while(<R>) {
         $windows_os ? $_ =~ s/\r?\n$// : chomp;
         my $l = $_;
+        my $ol = $l; # keep the unmodified line for error reporting
         my $column = 0;
 
         # check for !checksrc! commands
@@ -283,12 +286,47 @@ sub scanfile {
                       $line, length($1), $file, $l, "Trailing whitespace");
         }
 
+        # ------------------------------------------------------------
+        # Above this marker, the checks were done on lines *including*
+        # comments
+        # ------------------------------------------------------------
+
+        # strip off C89 comments
+
+      comment:
+        if(!$incomment) {
+            if($l =~ s/\/\*.*\*\// /g) {
+                # full /* comments */ were removed!
+            }
+            if($l =~ s/\/\*.*//) {
+                # start of /* comment was removed
+                $incomment = 1;
+            }
+        }
+        else {
+            if($l =~ s/.*\*\///) {
+                # end of comment */ was removed
+                $incomment = 0;
+                goto comment;
+            }
+            else {
+                # still within a comment
+                $l="";
+            }
+        }
+
+        # ------------------------------------------------------------
+        # Below this marker, the checks were done on lines *without*
+        # comments
+        # ------------------------------------------------------------
+
         # crude attempt to detect // comments without too many false
         # positives
         if($l =~ /^([^"\*]*)[^:"]\/\//) {
             checkwarn("CPPCOMMENTS",
                       $line, length($1), $file, $l, "\/\/ comment");
         }
+
         # check spaces after for/if/while
         if($l =~ /^(.*)(for|if|while) \(/) {
             if($1 =~ / *\#/) {
@@ -379,13 +417,13 @@ sub scanfile {
         # check for space before the semicolon last in a line
         if($l =~ /^(.*[^ ].*) ;$/) {
             checkwarn("SPACESEMILCOLON",
-                      $line, length($1), $file, $l, "space before last semicolon");
+                      $line, length($1), $file, $ol, "space before last semicolon");
         }
 
         # scan for use of banned functions
         if($l =~ /^(.*\W)(sprintf|vsprintf|strcat|strncat|gets)\s*\(/) {
             checkwarn("BANNEDFUNC",
-                      $line, length($1), $file, $l,
+                      $line, length($1), $file, $ol,
                       "use of $2 is banned");
         }
 
@@ -394,7 +432,7 @@ sub scanfile {
             my $mode = $2;
             if($mode !~ /b/) {
                 checkwarn("FOPENMODE",
-                          $line, length($1), $file, $l,
+                          $line, length($1), $file, $ol,
                           "use of non-binary fopen without FOPEN_* macro: $mode");
             }
         }
@@ -404,7 +442,7 @@ sub scanfile {
         # line
         if((($prevl =~ /\)\z/) && ($prevl !~ /^ *#/)) && ($l =~ /^( +)\{/)) {
             checkwarn("BRACEPOS",
-                      $line, length($1), $file, $l, "badly placed open brace");
+                      $line, length($1), $file, $ol, "badly placed open brace");
         }
 
         # if the previous line starts with if/while/for AND ends with an open
@@ -419,7 +457,7 @@ sub scanfile {
                 my $expect = $first+$indent;
                 if($expect != $second) {
                     my $diff = $second - $first;
-                    checkwarn("INDENTATION", $line, length($1), $file, $l,
+                    checkwarn("INDENTATION", $line, length($1), $file, $ol,
                               "not indented $indent steps, uses $diff)");
 
                 }
@@ -427,12 +465,15 @@ sub scanfile {
         }
 
         $line++;
-        $prevl = $l;
+        $prevl = $ol;
     }
 
     if(!$copyright) {
         checkwarn("COPYRIGHT", 1, 0, $file, "", "Missing copyright statement", 1);
     }
+    if($incomment) {
+        checkwarn("OPENCOMMENT", 1, 0, $file, "", "Missing closing comment", 1);
+    }
 
     checksrc_endoffile($file);