--- loncom/Attic/lchtmldir	2004/10/18 10:56:50	1.9
+++ loncom/Attic/lchtmldir	2004/10/20 09:30:57	1.11
@@ -67,11 +67,15 @@
 #   horses and other fine issues:
 #
 use strict; 
+use Fcntl qw(:mode);
+use DirHandle;
+
 
 $ENV{'PATH'} = '/bin:/usr/bin:/usr/local/sbin:/home/httpd/perl';
 delete @ENV{qw{IFS CDPATH ENV BASH_ENV}};
 
 my $DEBUG = 0;                         # .nonzero -> Debug printing enabled.
+my $path_sep = "/";		# Unix like operating systems.
 
 
 # If the UID of the running process is not www exit with error.
@@ -228,6 +232,13 @@ if($authentication eq "unix:") {	# Unix
     # is that a file system user is being demoted to internal user...
 
     if($authentication eq "internal:") {
+	#  In case the user was a unix/filesystem authenticated user,
+	#  we'll take a bit of time here to write  a script in the
+	#  user's home directory that can reset ownerships and permissions
+	#  back the way the used to be.
+
+	&write_restore_script($homedir);
+
 	&System("/bin/chown -R root:root ".$homedir);
     }
     &System("/bin/chown -R www:www  ".$fulldir);
@@ -305,5 +316,136 @@ sub System {
 }
 
 
+
+
+
+#
+#   This file contains code to recursively process
+#   a Directory.  This is a bit more powerful
+#   than File::Find in that we pass the full
+#   stat info to the processing function.
+#     For each file in the specified directory subtree, 
+#   The user's Code reference is invoked for all files, regular and otherwise
+#   except:
+#      ., ..
+#
+#  Parameters:
+#     code_ref    - Code reference, invoked for each file in the tree.
+#                   as follows:  CodeRef(directory, name, statinfo)
+#                   directory the path to the directory holding the file.
+#                   name      the name of the file within Directory.
+#                   statinfo  a reference to the stat of the file.
+#     start_dir   - The starting point of the directory walk.
+#
+# NOTE:
+#   Yes, we could have just used File::Find, but since we have to get the
+#   stat anyway, this is actually simpler, as File::Find would have gotten
+#   the stat to figure out the file type and then we would have gotten it
+#   again.
+#
+
+sub process_tree {
+    my ($code_ref, $start_dir)  = @_;
+
+    my $dir = new DirHandle $start_dir; 
+    if (!defined($dir)) {
+        print "Failed to  open dirhandle: $start_dir\n";
+    }
+
+    # Now iterate through this level of the tree:
+
+    while (defined (my $name = $dir->read)) {
+	next if $name =~/^\.\.?$/;       # Skip ., .. (see cookbook pg 319)
+	
+	my $full_name   = $start_dir.$path_sep.$name; # Full filename path.
+	my @stat_info  = lstat($full_name);
+	my $mode       = $stat_info[2];
+	my $type       = $mode & 0170000; #  File type.
+
+	# Unless the file type is a symlink, call the user code:
+
+	unless ($type == S_IFLNK) {
+	    &$code_ref($start_dir, $name, \@stat_info);
+	}
+
+	# If the entry is a directory, we need to recurse:
+
+
+	if (($type ==  S_IFDIR) != 0) {
+	    &process_tree($code_ref, $full_name);
+	}
+    }
+
+}
+#
+#   Callback from process_tree to write the script lines
+#   requried to restore files to current ownership and permission.
+# Parameters:
+#    dir         - Name of the directory the file lives in.
+#    name        - Name of the file itself.
+#    statinfo    - Array from lstat called on the file.
+#
+#
+sub write_script {
+    my ($dir, $name, $statinfo) = @_;
+
+    my $fullname = $dir.$path_sep.$name;
+
+    #  We're going to '' the name, but we need to deal with embedded
+    #  ' characters.  Using " is much worse as we'd then have to
+    #  escape all the shell escapes too.  This way all we need
+    #  to do is replace ' with '\''
+
+    $fullname =~ s/\'/\'\\\'\'/g;
+
+    my $perms    = $statinfo->[2] & 0777; # Just permissions.
+    printf CHMODSCRIPT "chmod 0%o '%s'\n", $perms, $fullname;
+    printf CHMODSCRIPT "chown %d:%d '%s'\n", $statinfo->[4], $statinfo->[5], 
+                                         $fullname
+
+
+}
+# 
+#    Write a script in the user's home directory that can restore
+#    the permissions and ownerhips of all the files in the directory
+#    tree to their current ownerships and permissions.  This is done
+#    prior to making the user into an internally authenticated user
+#    in case they were previously file system authenticated and
+#    need to go back.
+#      The file we will create will be of the form
+#        restore_n.sh  Where n is a number that we will keep
+#   incrementing as needed until there isn't a file by that name.
+#   
+# Parameters:
+#    dir      - Path to the user's home directory.
+#
+sub write_restore_script {
+    my ($dir)   = @_;
+
+    #   Create a unique file:
+
+    my $version_number     = 0;
+    my $filename           = 'restore_'.$version_number.'.sh';
+    my $full_name           = $dir.$path_sep.$filename;
+
+    while(-e $full_name) {
+	$version_number++;
+	$filename         = 'restore_'.$version_number.'.sh';
+	$full_name        = $dir.$path_sep.$filename;
+    }
+    # $full_name is the full path of a file that does not yet exist
+    # of the form we want:
+
+    open(CHMODSCRIPT, "> $full_name");
+
+    &process_tree(\&write_script, $dir);
+
+    close(CHMODSCRIPT);
+
+    chmod(0750, $full_name);
+
+}
+
+