--- loncom/LONCAPA.pm	2008/11/20 15:19:33	1.27
+++ loncom/LONCAPA.pm	2011/05/14 16:12:53	1.31
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Base routines
 #
-# $Id: LONCAPA.pm,v 1.27 2008/11/20 15:19:33 jms Exp $
+# $Id: LONCAPA.pm,v 1.31 2011/05/14 16:12:53 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -44,6 +44,7 @@ my $loncapa_max_wait_time = 13;
 use vars qw($match_domain   $match_not_domain
 	    $match_username $match_not_username
 	    $match_courseid $match_not_courseid
+            $match_community
 	    $match_name
             $match_lonid
 	    $match_handle   $match_not_handle);
@@ -56,32 +57,20 @@ our @EXPORT = qw(&add_get_param    &esca
 our @EXPORT_OK = qw($match_domain   $match_not_domain
 		    $match_username $match_not_username
 		    $match_courseid $match_not_courseid
+                    $match_community
 		    $match_name
 		    $match_lonid
 		    $match_handle   $match_not_handle);
 our %EXPORT_TAGS = ( 'match' =>[qw($match_domain   $match_not_domain
 				   $match_username $match_not_username
 				   $match_courseid $match_not_courseid
+                                   $match_community
 				   $match_name
 				   $match_lonid
 				   $match_handle   $match_not_handle)],);
 my %perlvar;
 
 
-=pod
-
-=head2 NOTE:
-
-add_get_param()
-
-Inputs are a url, and a hash ref of
-form name => value pairs
-takes care of properly adding the form name elements and values to the 
-the url doing proper escaping of the values and joining with ? or & as 
-needed
-
-=cut
-
 sub add_get_param {
     my ($url,$form_data) = @_;
     my $needs_question_mark = ($url !~ /\?/);
@@ -114,8 +103,8 @@ sub unescape {
     return $str;
 }
 
-$match_domain     = $LONCAPA::domain_re     = qr{[\w\-.]+};
-$match_not_domain = $LONCAPA::not_domain_re = qr{[^\w\-.]+};
+$match_domain     = $LONCAPA::domain_re     = qr{[[:alnum:]\-.]+};
+$match_not_domain = $LONCAPA::not_domain_re = qr{[^[:alnum:]\-.]+};
 sub clean_domain {
     my ($domain) = @_;
     $domain =~ s/$match_not_domain//g;
@@ -133,6 +122,7 @@ sub clean_username {
 
 
 $match_courseid     = $LONCAPA::courseid_re     = qr{\d[\w\-.]+};
+$match_community    =$LONCAPA::community_re     = qr{0[\w\-.]+};
 $match_not_courseid = $LONCAPA::not_courseid_re = qr{[^\w\-.]+};
 sub clean_courseid {
     my ($courseid) = @_;
@@ -165,6 +155,47 @@ sub clean_handle {
     return $handle;
 }
 
+#
+# -- Ensure another process for same filesystem action is not running.
+#    lond uses for: apachereload; loncron uses for: lciptables
+#
+
+sub try_to_lock {
+    my ($lockfile)=@_;
+    my $currentpid;
+    my $lastpid;
+    # Do not manipulate lock file as root
+    if ($>==0) {
+        return 0;
+    }
+    # Try to generate lock file.
+    # Wait 3 seconds.  If same process id is in
+    # lock file, then assume lock file is stale, and
+    # go ahead.  If process id's fluctuate, try
+    # for a maximum of 10 times.
+    for (0..10) {
+        if (-e $lockfile) { 
+            open(LOCK,"<$lockfile");
+            $currentpid=<LOCK>;
+            close LOCK;
+            if ($currentpid==$lastpid) {
+                last;
+            }
+            sleep 3;
+            $lastpid=$currentpid;
+        } else {
+            last;
+        }
+        if ($_==10) {
+            return 0;
+        }
+    }
+    open(LOCK,">$lockfile");
+    print LOCK $$;
+    close LOCK;
+    return 1;
+}
+
 # -------------------------------------------- Return path to profile directory
 
 sub propath {
@@ -175,8 +206,7 @@ sub propath {
     $subdir =~ s/(.)(.)(.).*/$1\/$2\/$3/;
     my $proname="$perlvar{'lonUsersDir'}/$udom/$subdir/$uname";
     return $proname;
-} 
-
+}
 
 sub tie_domain_hash {
     my ($domain,$namespace,$how,$loghead,$logtail) = @_;
@@ -385,6 +415,7 @@ BEGIN {
 
 __END__
 
+=pod
 
 =head1 NAME
 
@@ -409,12 +440,14 @@ unpack non-word characters into CGI-comp
  pack CGI-compatible hex codes into actual non-word ASCII character
 
 =item  add_get_param()
+
+Append escaped form elements (name=value etc.) to a url.
  
  Inputs:  url (with or without exit GET from parameters), hash ref of
               form name => value pairs
 
- Return: url with properly added the form name elements and values to the 
-         the url doing proper escaping of the values and joining with ? or &
+ Return: url with form name elements and values appended to the 
+         the url, doing proper escaping of the values and joining with ? or &
          as needed
 
 =item clean_handle()