snort-dev, tracking of enabe disable rules after updates, add oinkmaster.pl, improve snorts performance, reduce snorts memory by 52 mb, more info in snort.xml and snort_advanced

1 files changed, 2754 insertions, 0 deletions

diff --git a/config/snort-dev/bin/oinkmaster_contrib/oinkmaster.pl b/config/snort-dev/bin/oinkmaster_contrib/oinkmaster.pl
new file mode 100644
index 00000000..f9c4d215
--- /dev/null
+++ b/config/snort-dev/bin/oinkmaster_contrib/oinkmaster.pl
@@ -0,0 +1,2754 @@
+#!/usr/bin/perl -w
+
+# $Id: oinkmaster.pl,v 1.406 2006/02/10 13:02:44 andreas_o Exp $ #
+
+# Copyright (c) 2001-2006 Andreas Östling <andreaso@it.su.se>
+# All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or
+#  without modification, are permitted provided that the following
+#  conditions are met:
+#
+#  1. Redistributions of source code must retain the above
+#     copyright notice, this list of conditions and the following
+#     disclaimer.
+#
+#  2. Redistributions in binary form must reproduce the above
+#     copyright notice, this list of conditions and the following
+#     disclaimer in the documentation and/or other materials
+#     provided with the distribution.
+#
+#  3. Neither the name of the author nor the names of its
+#     contributors may be used to endorse or promote products
+#     derived from this software without specific prior written
+#     permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+# CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+# OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+# EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+use 5.006001;
+
+use strict;
+use File::Basename;
+use File::Copy;
+use File::Path;
+use File::Spec;
+use Getopt::Long;
+use File::Temp qw(tempdir);
+
+sub show_usage();
+sub parse_cmdline($);
+sub read_config($ $);
+sub sanity_check();
+sub download_file($ $);
+sub unpack_rules_archive($ $ $);
+sub join_tmp_rules_dirs($ $ @);
+sub process_rules($ $ $ $ $ $);
+sub process_rule($ $ $ $ $ $ $ $);
+sub setup_rules_hash($ $);
+sub get_first_only($ $ $);
+sub print_changes($ $);
+sub print_changetype($ $ $ $);
+sub print_summary_change($ $);
+sub make_backup($ $);
+sub get_changes($ $ $);
+sub update_rules($ @);
+sub copy_rules($ $);
+sub is_in_path($);
+sub get_next_entry($ $ $ $ $ $);
+sub get_new_vars($ $ $ $);
+sub add_new_vars($ $);
+sub write_new_vars($ $);
+sub msdos_to_cygwin_path($);
+sub parse_mod_expr($ $ $ $);
+sub untaint_path($);
+sub approve_changes();
+sub parse_singleline_rule($ $ $);
+sub join_multilines($);
+sub minimize_diff($ $);
+sub catch_sigint();
+sub clean_exit($);
+
+
+my $VERSION            = 'Oinkmaster v2.0, Copyright (C) 2001-2006 '.
+                         'Andreas Östling <andreaso@it.su.se>';
+my $OUTFILE            = 'snortrules.tar.gz';
+my $RULES_DIR          = 'rules';
+
+my $PRINT_NEW          = 1;
+my $PRINT_OLD          = 2;
+my $PRINT_BOTH         = 3;
+
+my %config = (
+    careful            => 0,
+    check_removed      => 0,
+    config_test_mode   => 0,
+    enable_all         => 0,
+    interactive        => 0,
+    make_backup        => 0,
+    minimize_diff      => 0,
+    min_files          => 1,
+    min_rules          => 1,
+    quiet              => 0,
+    summary_output     => 0,
+    super_quiet        => 0,
+    update_vars        => 0,
+    use_external_bins  => 1,
+    verbose            => 0,
+    use_path_checks    => 1,
+    rule_actions       => "alert|drop|log|pass|reject|sdrop|activate|dynamic",
+    tmp_basedir        => $ENV{TMP} || $ENV{TMPDIR} || $ENV{TEMPDIR} || '/tmp',
+);
+
+
+# Regexp to match the start of a multi-line rule.
+# %ACTIONS% will be replaced with content of $config{actions} later.
+# sid and msg will then be looked for in parse_singleline_rule().
+my $MULTILINE_RULE_REGEXP  = '^\s*#*\s*(?:%ACTIONS%)'.
+                             '\s.*\\\\\s*\n$'; # ';
+
+# Regexp to match a single-line rule.
+# sid and msg will then be looked for in parse_singleline_rule().
+my $SINGLELINE_RULE_REGEXP = '^\s*#*\s*(?:%ACTIONS%)'.
+                             '\s.+;\s*\)\s*$'; # ';
+
+# Match var line where var name goes into $1.
+my $VAR_REGEXP = '^\s*var\s+(\S+)\s+(\S+)';
+
+# Allowed characters in misc paths/filenames, including the ones in the tarball.
+my $OK_PATH_CHARS = 'a-zA-Z\d\ _\(\)\[\]\.\-+:\\\/~@,=';
+
+# Default locations for configuration file.
+my @DEFAULT_CONFIG_FILES = qw(
+    /etc/oinkmaster.conf
+    /usr/local/etc/oinkmaster.conf
+);
+
+my @DEFAULT_DIST_VAR_FILES = qw(
+  snort.conf
+);
+
+my (%loaded, $tmpdir);
+
+
+
+#### MAIN ####
+
+# No buffering.
+select(STDERR);
+$| = 1;
+select(STDOUT);
+$| = 1;
+
+
+my $start_date = scalar(localtime);
+
+# Assume the required Perl modules are available if we're on Windows.
+$config{use_external_bins} = 0 if ($^O eq "MSWin32");
+
+# Parse command line arguments and add at least %config{output_dir}.
+parse_cmdline(\%config);
+
+# If no config was specified on command line, look for one in default locations.
+if ($#{$config{config_files}} == -1) {
+    foreach my $config (@DEFAULT_CONFIG_FILES) {
+        if (-e "$config") {
+            push(@{${config{config_files}}}, $config);
+            last;
+        }
+    }
+}
+
+# If no dist var file was specified on command line, set to default file(s).
+if ($#{$config{dist_var_files}} == -1) {
+    foreach my $var_file (@DEFAULT_DIST_VAR_FILES) {
+        push(@{${config{dist_var_files}}}, $var_file);
+    }
+}
+
+# If config is still not defined, we can't continue.
+if ($#{$config{config_files}} == -1) {
+    clean_exit("configuration file not found in default locations\n".
+               "(@DEFAULT_CONFIG_FILES)\n".
+               "Put it there or use the \"-C <file>\" argument.");
+}
+
+read_config($_, \%config) for @{$config{config_files}};
+
+# Now substitute "%ACTIONS%" with $config{rule_actions}, which may have
+# been modified after reading the config file.
+$SINGLELINE_RULE_REGEXP =~ s/%ACTIONS%/$config{rule_actions}/;
+$MULTILINE_RULE_REGEXP  =~ s/%ACTIONS%/$config{rule_actions}/;
+
+# If we're told not to use external binaries, load the Perl modules now.
+unless ($config{use_external_bins}) {
+    print STDERR "Loading Perl modules.\n" if ($config{verbose});
+
+    eval {
+        require IO::Zlib;
+        require Archive::Tar;
+        require LWP::UserAgent;
+    };
+
+    clean_exit("failed to load required Perl modules:\n\n$@\n".
+               "Install them or set use_external_bins to 1 ".
+               "if you want to use external binaries instead.")
+      if ($@);
+}
+
+
+# Do some basic sanity checking and exit if something fails.
+# A new PATH will be set.
+sanity_check();
+
+$SIG{INT} = \&catch_sigint;
+
+# Create temporary dir.
+$tmpdir = tempdir("oinkmaster.XXXXXXXXXX", DIR => File::Spec->rel2abs($config{tmp_basedir}))
+  or clean_exit("could not create temporary directory in $config{tmp_basedir}: $!");
+
+# If we're in config test mode and have come this far, we're done.
+if ($config{config_test_mode}) {
+    print "No fatal errors in configuration.\n";
+    clean_exit("");
+}
+
+umask($config{umask}) if exists($config{umask});
+
+# Download and unpack all the rules archives into separate tmp dirs.
+my @url_tmpdirs;
+foreach my $url (@{$config{url}}) {
+    my $url_tmpdir = tempdir("url.XXXXXXXXXX", DIR => $tmpdir)
+      or clean_exit("could not create temporary directory in $tmpdir: $!");
+    push(@url_tmpdirs, "$url_tmpdir/$RULES_DIR");
+    if ($url =~ /^dir:\/\/(.+)/) {
+        mkdir("$url_tmpdir/$RULES_DIR")
+          or clean_exit("Could not create $url_tmpdir/$RULES_DIR");
+        copy_rules($1, "$url_tmpdir/$RULES_DIR");
+    } else {
+        download_file($url, "$url_tmpdir/$OUTFILE");
+        unpack_rules_archive("$url", "$url_tmpdir/$OUTFILE", $RULES_DIR);
+    }
+}
+
+# Copy all rules files from the tmp dirs into $RULES_DIR in the tmp directory.
+# File matching 'skipfile' a directive will not be copied.
+# Filenames (with full path) will be stored as %new_files{filename}.
+# Will exit in case of duplicate filenames.
+my $num_files = join_tmp_rules_dirs("$tmpdir/$RULES_DIR", \my %new_files, @url_tmpdirs);
+
+# Make sure we have at least the minimum number of files.
+clean_exit("not enough rules files in downloaded rules archive(s).\n".
+           "Number of rules files is $num_files but minimum is set to $config{min_files}.")
+  if ($num_files < $config{min_files});
+
+# This is to read in possible 'localsid' rules.
+my %rh_tmp = setup_rules_hash(\%new_files, $config{output_dir});
+
+# Disable/modify/clean downloaded rules.
+my $num_rules = process_rules(\@{$config{sid_modify_list}},
+                              \%{$config{sid_disable_list}},
+                              \%{$config{sid_enable_list}},
+                              \%{$config{sid_local_list}},
+                              \%rh_tmp,
+                              \%new_files);
+
+# Make sure we have at least the minimum number of rules.
+clean_exit("not enough rules in downloaded archive(s).\n".
+           "Number of rules is $num_rules but minimum is set to $config{min_rules}.")
+  if ($num_rules < $config{min_rules});
+
+# Setup a hash containing the content of all processed rules files.
+my %rh = setup_rules_hash(\%new_files, $config{output_dir});
+
+# Compare the new rules to the old ones.
+my %changes = get_changes(\%rh, \%new_files, $RULES_DIR);
+
+# Check for variables that exist in dist snort.conf(s) but not in local snort.conf.
+get_new_vars(\%changes, \@{$config{dist_var_files}}, $config{varfile}, \@url_tmpdirs)
+  if ($config{update_vars});
+
+
+# Find out if something had changed.
+my $something_changed = 0;
+
+$something_changed = 1
+  if (keys(%{$changes{modified_files}}) ||
+      keys(%{$changes{added_files}})    ||
+      keys(%{$changes{removed_files}})  ||
+      $#{$changes{new_vars}} > -1);
+
+
+# Update files listed in %changes{modified_files} (copy the new files
+# from the temporary directory into our output directory) and add new
+# variables to the local snort.conf if requested, unless we're running in
+# careful mode. Create backup first if running with -b.
+my $printed = 0;
+if ($something_changed) {
+    if ($config{careful}) {
+        print STDERR "Skipping backup since we are running in careful mode.\n"
+          if ($config{make_backup} && (!$config{quiet}));
+    } else {
+        if ($config{interactive}) {
+            print_changes(\%changes, \%rh);
+            $printed = 1;
+        }
+
+        if (!$config{interactive} || ($config{interactive} && approve_changes)) {
+            make_backup($config{output_dir}, $config{backup_dir})
+              if ($config{make_backup});
+
+            add_new_vars(\%changes, $config{varfile})
+              if ($config{update_vars});
+
+            update_rules($config{output_dir}, keys(%{$changes{modified_files}}));
+        }
+    }
+} else {
+    print STDERR "No files modified - no need to backup old files, skipping.\n"
+      if ($config{make_backup} && !$config{quiet});
+}
+
+print "\nOinkmaster is running in careful mode - not updating anything.\n"
+  if ($something_changed && $config{careful});
+
+print_changes(\%changes, \%rh)
+  if (!$printed && ($something_changed || !$config{quiet}));
+
+
+# Everything worked. Do a clean exit without any error message.
+clean_exit("");
+
+
+# END OF MAIN #
+
+
+
+# Show usage information and exit.
+sub show_usage()
+{
+    my $progname = basename($0);
+
+    print STDERR << "RTFM";
+
+$VERSION
+
+Usage: $progname -o <outdir> [options]
+
+<outdir> is where to put the new files.
+This should be the directory where you store your Snort rules.
+
+Options:
+-b <dir>  Backup your old rules into <dir> before overwriting them
+-c        Careful mode (dry run) - check for changes but do not update anything
+-C <file> Use this configuration file instead of the default
+          May be specified multiple times to load multiple files
+-e        Enable all rules that are disabled by default
+-h        Show this usage information
+-i        Interactive mode - you will be asked to approve the changes (if any)
+-m        Minimize diff when printing result by removing common parts in rules
+-q        Quiet mode - no output unless changes were found
+-Q        Super-quiet mode - like -q but even more quiet
+-r        Check for rules files that exist in the output directory
+          but not in the downloaded rules archive
+-s        Leave out details in rules results, just print SID, msg and filename
+-S <file> Look for new variables in this file in the downloaded archive instead
+          of the default (@DEFAULT_DIST_VAR_FILES). Used in conjunction with -U.
+          May be specified multiple times to search multiple files.
+-T        Config test - just check configuration file(s) for errors/warnings
+-u <url>  Download from this URL instead of URL(s) in the configuration file
+          (http|https|ftp|file|scp:// ... .tar.gz|.gz, or dir://<dir>)
+          May be specified multiple times to grab multiple rules archives
+-U <file> Merge new variables from downloaded snort.conf(s) into <file>
+-v        Verbose mode (debug)
+-V        Show version and exit
+
+RTFM
+    exit;
+}
+
+
+
+# Parse the command line arguments and exit if we don't like them.
+sub parse_cmdline($)
+{
+    my $cfg_ref = shift;
+
+    Getopt::Long::Configure("bundling");
+
+    my $cmdline_ok = GetOptions(
+        "b=s" => \$$cfg_ref{backup_dir},
+        "c"   => \$$cfg_ref{careful},
+        "C=s" => \@{$$cfg_ref{config_files}},
+        "e"   => \$$cfg_ref{enable_all},
+        "h"   => \&show_usage,
+        "i"   => \$$cfg_ref{interactive},
+        "m"   => \$$cfg_ref{minimize_diff},
+        "o=s" => \$$cfg_ref{output_dir},
+        "q"   => \$$cfg_ref{quiet},
+        "Q"   => \$$cfg_ref{super_quiet},
+         "r"   => \$$cfg_ref{check_removed},
+        "s"   => \$$cfg_ref{summary_output},
+        "S=s" => \@{$$cfg_ref{dist_var_files}},
+        "T"   => \$$cfg_ref{config_test_mode},
+        "u=s" => \@{$$cfg_ref{url}},
+        "U=s" => \$$cfg_ref{varfile},
+        "v"   => \$$cfg_ref{verbose},
+        "V"   => sub {
+                     print "$VERSION\n";
+                     exit(0);
+                 }
+    );
+
+
+    show_usage unless ($cmdline_ok && $#ARGV == -1);
+
+    $$cfg_ref{quiet}       = 1 if ($$cfg_ref{super_quiet});
+    $$cfg_ref{update_vars} = 1 if ($$cfg_ref{varfile});
+
+    if ($$cfg_ref{backup_dir}) {
+        $$cfg_ref{backup_dir} = File::Spec->canonpath($$cfg_ref{backup_dir});
+        $$cfg_ref{make_backup} = 1;
+    }
+
+  # Cannot specify dist var files without specifying var target file.
+    if (@{$$cfg_ref{dist_var_files}} && !$$cfg_ref{update_vars}) {
+        clean_exit("You can not specify distribution variable file(s) without ".
+                   "also specifying local file to merge into");
+    }
+
+  # -o <dir> is the only required option in normal usage.
+    if ($$cfg_ref{output_dir}) {
+        $$cfg_ref{output_dir} = File::Spec->canonpath($$cfg_ref{output_dir});
+    } else {
+        warn("Error: no output directory specified.\n");
+        show_usage();
+    }
+
+  # Mark that url was set on command line (so we don't override it later).
+    $$cfg_ref{cmdline_url} = 1 if ($#{$config{url}} > -1);
+}
+
+
+
+# Read in stuff from the configuration file.
+sub read_config($ $)
+{
+    my $config_file = shift;
+    my $cfg_ref     = shift;
+    my $linenum     = 0;
+    my $multi;
+    my %templates;
+
+    $config_file = File::Spec->canonpath(File::Spec->rel2abs($config_file));
+
+    clean_exit("configuration file \"$config_file\" does not exist.\n")
+      unless (-e "$config_file");
+
+    clean_exit("\"$config_file\" is not a file.\n")
+      unless (-f "$config_file");
+
+    print STDERR "Loading $config_file\n"
+      unless ($config{quiet});
+
+  # Avoid loading the same file multiple times to avoid infinite recursion etc.
+    if ($^O eq "MSWin32") {
+        clean_exit("attempt to load \"$config_file\" twice.")
+          if ($loaded{$config_file}++);
+    } else {
+        my ($dev, $ino) = (stat($config_file))[0,1]
+          or clean_exit("unable to stat $config_file: $!");
+        clean_exit("attempt to load \"$config_file\" twice.")
+          if ($loaded{$dev, $ino}++);
+    }
+
+    open(CONF, "<", "$config_file")
+      or clean_exit("could not open configuration file \"$config_file\": $!");
+    my @conf = <CONF>;
+    close(CONF);
+
+    LINE:while ($_ = shift(@conf)) {
+        $linenum++;
+
+        unless ($multi) {
+            s/^\s*//;
+            s/^#.*//;
+        }
+
+      # Multi-line start/continuation.
+        if (/\\\s*\n$/) {
+            s/\\\s*\n$//;
+            s/^\s*#.*//;
+
+          # Be strict about removing #comments in modifysid/define_template statements, as
+          # they may contain other '#' chars.
+            if (defined($multi) && ($multi =~ /^modifysid/i || $multi =~ /^define_template/i)) {
+                s/#.*// if (/^\s*\d+[,\s\d]+#/);
+            } else {
+                s/\s*\#.*// unless (/^modifysid/i || /^define_template/i);
+            }
+
+            $multi .= $_;
+            next LINE;
+        }
+
+      # Last line of multi-line directive.
+        if (defined($multi)) {
+            $multi .= $_;
+            $_ = $multi;
+            undef($multi);
+        }
+
+      # Remove traling whitespaces (*after* a possible multi-line is rebuilt).
+	s/\s*$//;
+
+      # Remove comments unless it's a modifysid/define_template line
+      # (the "#" may be part of the modifysid expression).
+        s/\s*\#.*// unless (/^modifysid/i || /^define_template/i);
+
+      # Skip blank lines.
+        next unless (/\S/);
+
+      # Use a template and make $_ a "modifysid" line.
+        if (/^use_template\s+(\S+)\s+(\S+[^"]*)\s*(".*")*(?:#.*)*/i) {
+            my ($template_name, $sid, $args) = ($1, $2, $3);
+
+            if (exists($templates{$template_name})) {
+               my $template = $templates{$template_name};  # so we don't substitute %ARGx% globally
+
+              # Evaluate each "%ARGx%" in the template to the corresponding value.
+                if (defined($args)) {
+                    my @args = split(/"\s+"/, $args);
+                    foreach my $i (1 .. @args) {
+                        $args[$i - 1] =~ s/^"//;
+                        $args[$i - 1] =~ s/"$//;
+                        $template =~ s/%ARG$i%/$args[$i - 1]/g;
+                    }
+                }
+
+              # There should be no %ARGx% stuff left now.
+                if ($template =~ /%ARG\d%/) {
+                    warn("WARNING: too few arguments for template \"$template_name\"\n");
+                    $_ = "error";  # so it will be reported as an invalid line later
+                }
+
+                unless ($_ eq "error") {
+                    $_ = "modifysid $sid $template\n";
+                    print STDERR "Template \"$template_name\" expanded to: $_"
+                      if ($config{verbose});
+                }
+
+            } else {
+                warn("WARNING: template \"$template_name\" has not been defined\n");
+            }
+        }
+
+      # new template definition.
+        if (/^define_template\s+(\S+)\s+(".+"\s+\|\s+".*")\s*(?:#.*)*$/i) {
+            my ($template_name, $template) = ($1, $2);
+
+            if (exists($templates{$template_name})) {
+                warn("WARNING: line $linenum in $config_file: ".
+                     "template \"$template_name\" already defined, keeping old\n");
+            } else {
+                $templates{$template_name} = $template;
+            }
+
+      # modifysid <SIDORFILE[,SIDORFILE, ...]> "substthis" | "withthis"
+        } elsif (/^modifysids*\s+(\S+.*)\s+"(.+)"\s+\|\s+"(.*)"\s*(?:#.*)*$/i) {
+            my ($sid_list, $subst, $repl) = ($1, $2, $3);
+            warn("WARNING: line $linenum in $config_file is invalid, ignoring\n")
+              unless(parse_mod_expr(\@{$$cfg_ref{sid_modify_list}},
+                                    $sid_list, $subst, $repl));
+
+      # disablesid <SID[,SID, ...]>
+        } elsif (/^disablesids*\s+(\d.*)/i) {
+	    my $sid_list = $1;
+	    foreach my $sid (split(/\s*,\s*/, $sid_list)) {
+  	        if ($sid =~ /^\d+$/) {
+                    $$cfg_ref{sid_disable_list}{$sid}++;
+	        } else {
+                    warn("WARNING: line $linenum in $config_file: ".
+                         "\"$sid\" is not a valid SID, ignoring\n");
+	        }
+	    }
+
+      # localsid <SID[,SID, ...]>
+        } elsif (/^localsids*\s+(\d.*)/i) {
+	    my $sid_list = $1;
+	    foreach my $sid (split(/\s*,\s*/, $sid_list)) {
+  	        if ($sid =~ /^\d+$/) {
+                    $$cfg_ref{sid_local_list}{$sid}++;
+	        } else {
+                    warn("WARNING: line $linenum in $config_file: ".
+                         "\"$sid\" is not a valid SID, ignoring\n");
+	        }
+	    }
+
+      # enablesid <SID[,SID, ...]>
+        } elsif (/^enablesids*\s+(\d.*)/i) {
+	    my $sid_list = $1;
+	    foreach my $sid (split(/\s*,\s*/, $sid_list)) {
+  	        if ($sid =~ /^\d+$/) {
+                    $$cfg_ref{sid_enable_list}{$sid}++;
+	        } else {
+                    warn("WARNING: line $linenum in $config_file: ".
+                         "\"$sid\" is not a valid SID, ignoring\n");
+	        }
+	    }
+
+      # skipfile <file[,file, ...]>
+        } elsif (/^skipfiles*\s+(.*)/i) {
+	    my $args = $1;
+	    foreach my $file (split(/\s*,\s*/, $args)) {
+	        if ($file =~ /^\S+$/) {
+                    $config{verbose} && print STDERR "Adding file to ignore list: $file.\n";
+                    $$cfg_ref{file_ignore_list}{$file}++;
+		} else {
+                    warn("WARNING: line $linenum in $config_file is invalid, ignoring\n");
+		}
+	    }
+
+	} elsif (/^url\s*=\s*(.*)/i) {
+            push(@{$$cfg_ref{url}}, $1)
+              unless ($$cfg_ref{cmdline_url});
+
+	} elsif (/^path\s*=\s*(.+)/i) {
+	    $$cfg_ref{path} = $1;
+
+	} elsif (/^update_files\s*=\s*(.+)/i) {
+	    $$cfg_ref{update_files} = $1;
+
+	} elsif (/^rule_actions\s*=\s*(.+)/i) {
+	    $$cfg_ref{rule_actions} = $1;
+
+        } elsif (/^umask\s*=\s*([0-7]{4})$/i) {
+	    $$cfg_ref{umask} = oct($1);
+
+        } elsif (/^min_files\s*=\s*(\d+)/i) {
+            $$cfg_ref{min_files} = $1;
+
+        } elsif (/^min_rules\s*=\s*(\d+)/i) {
+            $$cfg_ref{min_rules} = $1;
+
+        } elsif (/^tmpdir\s*=\s*(.+)/i) {
+            $$cfg_ref{tmp_basedir} = $1;
+
+        } elsif (/^use_external_bins\s*=\s*([01])/i) {
+            $$cfg_ref{use_external_bins} = $1;
+
+        } elsif (/^scp_key\s*=\s*(.+)/i) {
+            $$cfg_ref{scp_key} = $1;
+
+        } elsif (/^use_path_checks\s*=\s*([01])/i) {
+            $$cfg_ref{use_path_checks} = $1;
+
+        } elsif (/^user_agent\s*=\s*(.+)/i) {
+            $$cfg_ref{user_agent} = $1;
+
+        } elsif (/^include\s+(\S+.*)/i) {
+             my $include = $1;
+             read_config($include, $cfg_ref);
+        } else {
+            warn("WARNING: line $linenum in $config_file is invalid, ignoring\n");
+        }
+    }
+}
+
+
+
+# Make a few basic tests to make sure things look ok.
+# Will also set a new PATH as defined in the config file.
+sub sanity_check()
+{
+   my @req_params   = qw(path update_files);  # required parameters in conf
+   my @req_binaries = qw(gzip tar);           # required binaries (unless we use modules)
+
+  # Can't use both quiet mode and verbose mode.
+    clean_exit("quiet mode and verbose mode at the same time doesn't make sense.")
+      if ($config{quiet} && $config{verbose});
+
+  # Can't use multiple output modes.
+    clean_exit("can't use multiple output modes at the same time.")
+      if ($config{minimize_diff} && $config{summary_output});
+
+  # Make sure all required variables are defined in the config file.
+    foreach my $param (@req_params) {
+        clean_exit("the required parameter \"$param\" is not defined in the configuration file.")
+          unless (exists($config{$param}));
+    }
+
+  # We now know a path was defined in the config, so set it.
+  # If we're under cygwin and path was specified as msdos style, convert
+  # it to cygwin style to avoid problems.
+    if ($^O eq "cygwin" && $config{path} =~ /^[a-zA-Z]:[\/\\]/) {
+        $ENV{PATH} = "";
+        foreach my $path (split(/;/, $config{path})) {
+	    $ENV{PATH} .= "$path:" if (msdos_to_cygwin_path(\$path));
+	}
+        chop($ENV{PATH});
+    } else {
+        $ENV{PATH} = $config{path};
+    }
+
+  # Reset environment variables that may cause trouble.
+    delete @ENV{'IFS', 'CDPATH', 'ENV', 'BASH_ENV'};
+
+  # Make sure $config{update_files} is a valid regexp.
+    eval {
+        "foo" =~ /$config{update_files}/;
+    };
+
+    clean_exit("update_files (\"$config{update_files}\") is not a valid regexp: $@")
+      if ($@);
+
+  # Make sure $config{rule_actions} is a valid regexp.
+    eval {
+        "foo" =~ /$config{rule_actions}/;
+    };
+
+    clean_exit("rule_actions (\"$config{rule_actions}\") is not a valid regexp: $@")
+      if ($@);
+
+  # If a variable file (probably local snort.conf) has been specified,
+  # it must exist. It must also be writable unless we're in careful mode.
+    if ($config{update_vars}) {
+	$config{varfile} = untaint_path($config{varfile});
+
+        clean_exit("variable file \"$config{varfile}\" does not exist.")
+          unless (-e "$config{varfile}");
+
+        clean_exit("variable file \"$config{varfile}\" is not a file.")
+          unless (-f "$config{varfile}");
+
+        clean_exit("variable file \"$config{varfile}\" is not writable by you.")
+          if (!$config{careful} && !-w "$config{varfile}");
+
+      # Make sure dist var files don't contain [back]slashes
+      # (probably means user confused it with local var file).
+        my %dist_var_files;
+        foreach my $dist_var_file (@{${config{dist_var_files}}}) {
+            clean_exit("variable file \"$dist_var_file\" specified multiple times")
+              if (exists($dist_var_files{$dist_var_file}));
+            $dist_var_files{$dist_var_file} = 1;
+            clean_exit("variable file \"$dist_var_file\" contains slashes or backslashes ".
+                       "but it must be specified as a filename (without path) ".
+                       "that exists in the downloaded rules, e.g. \"snort.conf\"")
+              if ($dist_var_file =~ /\// || $dist_var_file =~ /\\/);
+        }
+    }
+
+  # Make sure all required binaries can be found, unless
+  # we're used to use Perl modules instead.
+  # Wget is only required if url is http[s] or ftp.
+    if ($config{use_external_bins}) {
+        foreach my $binary (@req_binaries) {
+            clean_exit("$binary not found in PATH ($ENV{PATH}).")
+              unless (is_in_path($binary));
+        }
+    }
+
+  # Make sure $url is defined (either by -u <url> or url=... in the conf).
+    clean_exit("URL not specified. Specify at least one \"url=<url>\" in the \n".
+               "Oinkmaster configuration file or use the \"-u <url>\" argument")
+      if ($#{$config{url}} == -1);
+
+  # Make sure all urls look ok, and untaint them.
+    my @urls = @{$config{url}};
+    $#{$config{url}} = -1;
+    foreach my $url (@urls) {
+        clean_exit("incorrect URL: \"$url\"")
+          unless ($url =~ /^((?:https*|ftp|file|scp):\/\/.+\.(?:tar\.gz|tgz))$/
+            || $url =~ /^(dir:\/\/.+)/);
+        my $ok_url = $1;
+
+        if ($ok_url =~ /^dir:\/\/(.+)/) {
+            my $dir = untaint_path($1);
+            clean_exit("\"$dir\" does not exist or is not a directory")
+              unless (-d $dir);
+
+          # Simple check if the output dir is specified as url (probably a mistake).
+            if (File::Spec->canonpath(File::Spec->rel2abs($dir))
+              eq File::Spec->canonpath(File::Spec->rel2abs($config{output_dir}))) {
+                clean_exit("Download directory can not be same as output directory");
+            }
+        }
+        push(@{$config{url}}, $ok_url);
+    }
+
+  # Wget must be found if url is http[s]:// or ftp://.
+    if ($config{use_external_bins}) {
+        clean_exit("wget not found in PATH ($ENV{PATH}).")
+          if ($config{'url'} =~ /^(https*|ftp):/ && !is_in_path("wget"));
+    }
+
+  # scp must be found if scp://...
+    clean_exit("scp not found in PATH ($ENV{PATH}).")
+      if ($config{'url'} =~ /^scp:/ && !is_in_path("scp"));
+
+  # ssh key must exist if specified and url is scp://...
+    clean_exit("ssh key \"$config{scp_key}\" does not exist.")
+      if ($config{'url'} =~ /^scp:/ && exists($config{scp_key})
+        && !-e $config{scp_key});
+
+  # Untaint output directory string.
+    $config{output_dir} = untaint_path($config{output_dir});
+
+  # Make sure the output directory exists and is readable.
+    clean_exit("the output directory \"$config{output_dir}\" doesn't exist ".
+               "or isn't readable by you.")
+      if (!-d "$config{output_dir}" || !-x "$config{output_dir}");
+
+  # Make sure the output directory is writable unless running in careful mode.
+    clean_exit("the output directory \"$config{output_dir}\" isn't writable by you.")
+      if (!$config{careful} && !-w "$config{output_dir}");
+
+  # Make sure we have read permission on all rules files in the output dir,
+  # and also write permission unless we're in careful mode.
+  # This is to avoid bailing out in the middle of an execution if a copy
+  # fails because of permission problem.
+    opendir(OUTDIR, "$config{output_dir}")
+      or clean_exit("could not open directory $config{output_dir}: $!");
+
+    while ($_ = readdir(OUTDIR)) {
+        next if (/^\.\.?$/ || exists($config{file_ignore_list}{$_}));
+
+        if (/$config{update_files}/) {
+            unless (-r "$config{output_dir}/$_") {
+                closedir(OUTDIR);
+                clean_exit("no read permission on \"$config{output_dir}/$_\"\n".
+                           "Read permission is required on all rules files ".
+                           "inside the output directory.\n")
+            }
+
+            if (!$config{careful} && !-w "$config{output_dir}/$_") {
+                closedir(OUTDIR);
+                clean_exit("no write permission on \"$config{output_dir}/$_\"\n".
+                           "Write permission is required on all rules files ".
+                           "inside the output directory.\n")
+            }
+	}
+    }
+
+    closedir(OUTDIR);
+
+  # Make sure the backup directory exists and is writable if running with -b.
+    if ($config{make_backup}) {
+        $config{backup_dir} = untaint_path($config{backup_dir});
+        clean_exit("the backup directory \"$config{backup_dir}\" doesn't exist or ".
+                 "isn't writable by you.")
+          if (!-d "$config{backup_dir}" || !-w "$config{backup_dir}");
+    }
+
+  # Convert tmp_basedir to cygwin style if running cygwin and msdos style was specified.
+    if ($^O eq "cygwin" && $config{tmp_basedir} =~ /^[a-zA-Z]:[\/\\]/) {
+        msdos_to_cygwin_path(\$config{tmp_basedir})
+          or clean_exit("could not convert temporary dir to cygwin style");
+    }
+
+  # Make sure temporary directory exists.
+    clean_exit("the temporary directory \"$config{tmp_basedir}\" does not ".
+               "exist or isn't writable by you.")
+      if (!-d "$config{tmp_basedir}" || !-w "$config{tmp_basedir}");
+
+  # Also untaint it.
+    $config{tmp_basedir} = untaint_path($config{tmp_basedir});
+
+  # Make sure stdin and stdout are ttys if we're running in interactive mode.
+    clean_exit("you can not run in interactive mode when STDIN/STDOUT is not a TTY.")
+      if ($config{interactive} && !(-t STDIN && -t STDOUT));
+}
+
+
+
+# Download the rules archive.
+sub download_file($ $)
+{
+    my $url       = shift;
+    my $localfile = shift;
+    my $log       = "$tmpdir/wget.log";
+    my $ret;
+
+  # If there seems to be a password in the url, replace it with "*password*"
+  # and use new string when printing the url to screen.
+    my $obfuscated_url = $url;
+    $obfuscated_url = "$1:*password*\@$2"
+      if ($obfuscated_url =~ /^(\S+:\/\/.+?):.+?@(.+)/);
+
+  # Ofbuscate oinkcode as well.
+    $obfuscated_url = "$1*oinkcode*$2"
+      if ($obfuscated_url =~ /^(\S+:\/\/.+\.cgi\/)[0-9a-z]{32,64}(\/.+)/i);
+
+    my @user_agent_opt;
+    @user_agent_opt = ("-U", $config{user_agent}) if (exists($config{user_agent}));
+
+  # Use wget if URL starts with "http[s]" or "ftp" and we use external binaries.
+    if ($config{use_external_bins} && $url =~ /^(?:https*|ftp)/) {
+        print STDERR "Downloading file from $obfuscated_url... "
+          unless ($config{quiet});
+
+        if ($config{verbose}) {
+            print STDERR "\n";
+            my @wget_cmd = ("wget", "-v", "-O", $localfile, $url, @user_agent_opt);
+            clean_exit("could not download from $obfuscated_url")
+              if (system(@wget_cmd));
+
+        } else {
+            my @wget_cmd = ("wget", "-v", "-o", $log, "-O", $localfile, $url, @user_agent_opt);
+            if (system(@wget_cmd)) {
+                my $log_output;
+                open(LOG, "<", "$log")
+                  or clean_exit("could not open $log for reading: $!");
+                # Sanitize oinkcode in wget's log (password is automatically sanitized).
+                while (<LOG>) {
+                    $_ = "$1*oinkcode*$2"
+                      if (/(\S+:\/\/.+\.cgi\/)[0-9a-z]{32,64}(\/.+)/i);
+                    $log_output .= $_;
+                }
+                close(LOG);
+                clean_exit("could not download from $obfuscated_url. ".
+                           "Output from wget follows:\n\n $log_output");
+            }
+            print STDERR "done.\n" unless ($config{quiet});
+        }
+
+  # Use LWP if URL starts with "http[s]" or "ftp" and use_external_bins=0.
+    } elsif (!$config{use_external_bins} && $url =~ /^(?:https*|ftp)/) {
+        print STDERR "Downloading file from $obfuscated_url... "
+          unless ($config{quiet});
+
+        my %lwp_opt;
+        $lwp_opt{agent} = $config{user_agent} if (exists($config{user_agent}));
+
+        my $ua = LWP::UserAgent->new(%lwp_opt);
+        $ua->env_proxy;
+	my $request = HTTP::Request->new(GET => $url);
+	my $response = $ua->request($request, $localfile);
+
+        clean_exit("could not download from $obfuscated_url: " . $response->status_line)
+          unless $response->is_success;
+
+        print "done.\n" unless ($config{quiet});
+
+  # Grab file from local filesystem if file://...
+    } elsif ($url =~ /^file/) {
+        $url =~ s/^file:\/\///;
+
+	clean_exit("the file $url does not exist.")
+          unless (-e "$url");
+
+	clean_exit("the file $url is empty.")
+          unless (-s "$url");
+
+        print STDERR "Copying file from $url... "
+          unless ($config{quiet});
+
+        copy("$url", "$localfile")
+          or clean_exit("unable to copy $url to $localfile: $!");
+
+        print STDERR "done.\n"
+	  unless ($config{quiet});
+
+  # Grab file using scp if scp://...
+    } elsif ($url =~ /^scp/) {
+        $url =~ s/^scp:\/\///;
+
+        my @cmd;
+        push(@cmd, "scp");
+        push(@cmd, "-i", "$config{scp_key}") if (exists($config{scp_key}));
+        push(@cmd, "-q")                     if ($config{quiet});
+        push(@cmd, "-v")                     if ($config{verbose});
+        push(@cmd, "$url", "$localfile");
+
+        print STDERR "Copying file from $url using scp:\n"
+          unless ($config{quiet});
+
+        clean_exit("scp returned error when trying to copy $url")
+          if (system(@cmd));
+
+  # Unknown download method.
+    } else {
+        clean_exit("unknown or unsupported download method\n");
+    }
+
+  # Make sure the downloaded file actually exists.
+    clean_exit("failed to download $url: ".
+               "local target file $localfile doesn't exist after download.")
+      unless (-e "$localfile");
+
+  # Also make sure it's at least non-empty.
+    clean_exit("failed to download $url: local target file $localfile is empty ".
+               "after download (perhaps you're out of diskspace or file in url is empty?)")
+      unless (-s "$localfile");
+}
+
+
+
+# Copy all rules files from the tmp dirs (one for each url)
+# into a single directory inside the tmp dir, except for files
+# matching a 'skipfile' directive'.
+# Will exit in case of colliding filenames.
+sub join_tmp_rules_dirs($ $ @)
+{
+    my $rules_dir     = shift;
+    my $new_files_ref = shift;
+    my @url_tmpdirs   = @_;
+
+    my %rules_files;
+
+    clean_exit("failed to create directory \"$rules_dir\": $!")
+      unless (mkdir($rules_dir));
+
+    foreach my $url_tmpdir (@url_tmpdirs) {
+        opendir(URL_TMPDIR, "$url_tmpdir")
+          or clean_exit("could not open directory \"$url_tmpdir\": $!");
+
+        while ($_ = readdir(URL_TMPDIR)) {
+            next if (/^\.\.?$/ || exists($config{file_ignore_list}{$_}) || !/$config{update_files}/);
+
+            if (exists($rules_files{$_})) {
+                closedir(URL_TMPDIR);
+                clean_exit("a file called \"$_\" exists in multiple rules archives")
+            }
+
+          # Make sure it's a regular file.
+            unless (-f "$url_tmpdir/$_" && !-l "$url_tmpdir/$_") {
+                closedir(URL_TMPDIR);
+                clean_exit("downloaded \"$_\" is not a regular file.")
+            }
+
+            $rules_files{$_} = 1;
+            $$new_files_ref{"$rules_dir/$_"} = 1;
+
+            my $src_file = untaint_path("$url_tmpdir/$_");
+            unless (copy("$src_file", "$rules_dir")) {
+                closedir(URL_TMPDIR);
+                clean_exit("could not copy \"$src_file\" to \"$rules_dir\": $!");
+            }
+        }
+
+        closedir(URL_TMPDIR);
+    }
+
+    return (keys(%$new_files_ref));
+}
+
+
+
+# Make a few basic sanity checks on the rules archive and then
+# uncompress/untar it if everything looked ok.
+sub unpack_rules_archive($ $ $)
+{
+    my $url       = shift;  # only used when printing warnings/errors
+    my $archive   = shift;
+    my $rules_dir = shift;
+
+    my ($tar, @tar_content);
+
+    my $old_dir = untaint_path(File::Spec->rel2abs(File::Spec->curdir()));
+
+    my $dir = dirname($archive);
+    chdir("$dir") or clean_exit("$url: could not change directory to \"$dir\": $!");
+
+    if ($config{use_external_bins}) {
+
+      # Run integrity check on the gzip file.
+        clean_exit("$url: integrity check on gzip file failed (file transfer failed or ".
+                   "file in URL not in gzip format?).")
+          if (system("gzip", "-t", "$archive"));
+
+      # Decompress it.
+        system("gzip", "-d", "$archive")
+          and clean_exit("$url: unable to uncompress $archive.");
+
+      # Suffix has now changed from .tar.gz|.tgz to .tar.
+        $archive =~ s/\.gz$//;
+
+      # Make sure the .tar file now exists.
+      # (Gzip may not return an error if it was not a gzipped file...)
+        clean_exit("$url: failed to unpack gzip file (file transfer failed or ".
+                   "file in URL not in tar'ed gzip format?).")
+          unless (-e  "$archive");
+
+        my $stdout_file = "$tmpdir/tar_content.out";
+
+        open(OLDOUT, ">&STDOUT")      or clean_exit("could not dup STDOUT: $!");
+        open(STDOUT, ">$stdout_file") or clean_exit("could not redirect STDOUT: $!");
+
+        my $ret = system("tar", "tf", "$archive");
+
+        close(STDOUT);
+        open(STDOUT, ">&OLDOUT") or clean_exit("could not dup STDOUT: $!");
+        close(OLDOUT);
+
+        clean_exit("$url: could not list files in tar archive (is it broken?)")
+          if ($ret);
+
+        open(TAR, "$stdout_file") or clean_exit("failed to open $stdout_file: $!");
+        @tar_content = <TAR>;
+        close(TAR);
+
+ # use_external_bins=0
+    } else {
+        $tar = Archive::Tar->new($archive, 1);
+        clean_exit("$url: failed to read $archive (file transfer failed or ".
+                   "file in URL not in tar'ed gzip format?).")
+          unless (defined($tar));
+        @tar_content = $tar->list_files();
+    }
+
+  # Make sure we could grab some content from the tarball.
+    clean_exit("$url: could not list files in tar archive (is it broken?)")
+      if ($#tar_content < 0);
+
+  # For each filename in the archive, do some basic sanity checks.
+    foreach my $filename (@tar_content) {
+       chomp($filename);
+
+      # We don't want absolute filename.
+        clean_exit("$url: rules archive contains absolute filename. ".
+                   "Offending file/line:\n$filename")
+          if ($filename =~ /^\//);
+
+      # We don't want to have any weird characters anywhere in the filename.
+        clean_exit("$url: illegal character in filename in tar archive. Allowed are ".
+                   "$OK_PATH_CHARS\nOffending file/line:\n$filename")
+          if ($config{use_path_checks} && $filename =~ /[^$OK_PATH_CHARS]/);
+
+      # We don't want to unpack any "../../" junk (check is useless now though).
+        clean_exit("$url: filename in tar archive contains \"..\".\n".
+                   "Offending file/line:\n$filename")
+          if ($filename =~ /\.\./);
+    }
+
+ # Looks good. Now we can untar it.
+    print STDERR "Archive successfully downloaded, unpacking... "
+      unless ($config{quiet});
+
+    if ($config{use_external_bins}) {
+        clean_exit("failed to untar $archive.")
+          if system("tar", "xf", "$archive");
+    } else {
+        mkdir("$rules_dir") or clean_exit("could not create \"$rules_dir\" directory: $!\n");
+        foreach my $file ($tar->list_files) {
+            next unless ($file =~ /^$rules_dir\/[^\/]+$/);  # only ^rules/<file>$
+
+            my $content = $tar->get_content($file);
+
+          # Symlinks in the archive will make get_content return undef.
+            clean_exit("could not get content from file \"$file\" in downloaded archive, ".
+                       "make sure it is a regular file\n")
+              unless (defined($content));
+
+            open(RULEFILE, ">", "$file")
+              or clean_exit("could not open \"$file\" for writing: $!\n");
+            print RULEFILE $content;
+            close(RULEFILE);
+        }
+    }
+
+  # Make sure that non-empty rules directory existed in archive.
+  # We permit empty rules directory if min_files is set to 0 though.
+    clean_exit("$url: no \"$rules_dir\" directory found in tar file.")
+      unless (-d "$dir/$rules_dir");
+
+    my $num_files = 0;
+    opendir(RULESDIR, "$dir/$rules_dir")
+      or clean_exit("could not open directory \"$dir/$rules_dir\": $!");
+
+    while ($_ = readdir(RULESDIR)) {
+        next if (/^\.\.?$/);
+        $num_files++;
+    }
+
+    closedir(RULESDIR);
+
+    clean_exit("$url: directory \"$rules_dir\" in unpacked archive is empty")
+      if ($num_files == 0 && $config{min_files} != 0);
+
+    chdir($old_dir)
+      or clean_exit("could not change directory back to $old_dir: $!");
+
+    print STDERR "done.\n"
+      unless ($config{quiet});
+}
+
+
+
+# Open all rules files in the temporary directory and disable/modify all
+# rules/lines as requested in oinkmaster.conf, and then write back to the
+# same files. Also clean unwanted whitespaces and duplicate sids from them.
+sub process_rules($ $ $ $ $ $)
+{
+    my $modify_sid_ref  = shift;
+    my $disable_sid_ref = shift;
+    my $enable_sid_ref  = shift;
+    my $local_sid_ref   = shift;
+    my $rh_tmp_ref      = shift;
+    my $newfiles_ref    = shift;
+    my %sids;
+
+    my %stats = (
+        disabled => 0,
+        enabled  => 0,
+        modified => 0,
+        total    => 0,
+    );
+
+    warn("WARNING: all rules that are disabled by default will be enabled\n")
+      if ($config{enable_all} && !$config{quiet});
+
+    print STDERR "Processing downloaded rules... "
+      unless ($config{quiet});
+
+    print STDERR "\n"
+      if ($config{verbose});
+
+  # Phase #1 - process all active rules and store in temporary hash.
+  # In case of dups, we use the one with the highest rev.
+    foreach my $file (sort(keys(%$newfiles_ref))) {
+
+        open(INFILE, "<", "$file")
+          or clean_exit("could not open $file for reading: $!");
+	my @infile = <INFILE>;
+        close(INFILE);
+
+        my ($single, $multi, $nonrule, $msg, $sid);
+
+	RULELOOP:while (get_next_entry(\@infile, \$single, \$multi, \$nonrule, \$msg, \$sid)) {
+
+          # We don't care about non-rules in this phase.
+	    next RULELOOP if (defined($nonrule));
+
+          # Even if it was a single-line rule, we want a copy in $multi.
+	    $multi = $single unless (defined($multi));
+
+            my %rule = (
+                single => $single,
+                multi  => $multi,
+            );
+
+          # modify/disable/enable this rule as requested unless there is a matching
+          # localsid statement. Possible verbose messages and warnings will be printed.
+            unless (exists($$local_sid_ref{$sid})) {
+                process_rule($modify_sid_ref, $disable_sid_ref, $enable_sid_ref,
+                             \%rule, $sid, \%stats, 1, basename($file));
+            }
+
+            $stats{total}++;
+
+            $single = $rule{single};
+            $multi  = $rule{multi};
+
+          # Only care about active rules in this phase (the rule may have been
+          # disabled by a disablesid or a modifysid statement above, so we can't
+          # do this check earlier).
+	    next RULELOOP if ($multi =~ /^#/);
+
+          # Is it a dup? If so, see if this seems to be more recent (higher rev).
+            if (exists($sids{$sid})) {
+                warn("\nWARNING: duplicate SID in downloaded archive, SID=$sid, ".
+                     "only keeping rule with highest 'rev'\n")
+                  unless($config{super_quiet});
+
+                my ($old_rev) = ($sids{$sid}{single} =~ /\brev\s*:\s*(\d+)\s*;/);
+                my ($new_rev) = ($single             =~ /\brev\s*:\s*(\d+)\s*;/);
+
+              # This is so rules with a rev gets higher prio than
+              # rules without any rev.
+                $old_rev = -1 unless (defined($old_rev));
+                $new_rev = -1 unless (defined($new_rev));
+
+              # If this rev is higher than the one in the last stored rule with
+              # this sid, replace rule with this one. This is also done if the
+              # revs are equal because we assume the rule appearing last in the
+              # rules file is the more recent rule.
+                if ($new_rev >= $old_rev) {
+                    $sids{$sid}{single} = $single;
+                    $sids{$sid}{multi}  = $multi;
+                }
+
+          # No dup.
+            } else {
+                $sids{$sid}{single} = $single;
+                $sids{$sid}{multi}  = $multi;
+            }
+        }
+    }
+
+  # Phase #2 - read all rules files again, but when writing active rules
+  # back to the files, use the one stored in the sid hash (which is free of dups).
+    foreach my $file (sort(keys(%$newfiles_ref))) {
+
+        open(INFILE, "<", "$file")
+          or clean_exit("could not open $file for reading: $!");
+	my @infile = <INFILE>;
+        close(INFILE);
+
+      # Write back to the same file.
+	open(OUTFILE, ">", "$file")
+          or clean_exit("could not open $file for writing: $!");
+
+        my ($single, $multi, $nonrule, $msg, $sid);
+
+	RULELOOP:while (get_next_entry(\@infile, \$single, \$multi, \$nonrule, \$msg, \$sid)) {
+            if (defined($nonrule)) {
+                print OUTFILE "$nonrule";
+                next RULELOOP;
+            }
+
+          # Even if it was a single-line rule, we want a copy in $multi.
+            $multi = $single unless (defined($multi));
+
+          # If this rule is marked as localized and has not yet been written,
+          # write the old version to the new rules file.
+            if (exists($$local_sid_ref{$sid}) && !exists($sids{$sid}{printed})) {
+
+              # Just ignore the rule in the downloaded file if it doesn't
+              # exist in the same local file.
+                unless(exists($$rh_tmp_ref{old}{rules}{basename($file)}{$sid})) {
+                    warn("WARNING: SID $sid is marked as local and exists in ".
+                         "downloaded " . basename($file) . " but the SID does not ".
+                         "exist in the local file, ignoring rule\n")
+                      if ($config{verbose});
+
+                    next RULELOOP;
+                }
+
+                print OUTFILE $$rh_tmp_ref{old}{rules}{basename($file)}{$sid};
+                $sids{$sid}{printed} = 1;
+
+                warn("SID $sid is marked as local, keeping your version from ".
+                      basename($file) . ".\n".
+                     "Your version:       $$rh_tmp_ref{old}{rules}{basename($file)}{$sid}".
+                     "Downloaded version: $multi\n")
+                  if ($config{verbose});
+
+                next RULELOOP;
+            }
+
+            my %rule = (
+                single => $single,
+                multi  => $multi,
+            );
+
+          # modify/disable/enable this rule. Possible verbose messages and warnings
+          # will not be printed (again) as this was done in the first phase.
+          # We send the stats to a dummy var as this was collected on the
+          # first phase as well.
+            process_rule($modify_sid_ref, $disable_sid_ref, $enable_sid_ref,
+                         \%rule, $sid, \my %unused_stats, 0, basename($file));
+
+            $single = $rule{single};
+            $multi  = $rule{multi};
+
+          # Disabled rules are printed right back to the file, unless
+          # there also is an active rule with the same sid. Als o make
+          # sure we only print the sid once, even though it's disabled.
+            if ($multi =~ /^#/ && !exists($sids{$sid}) && !exists($sids{$sid}{printed})) {
+                print OUTFILE $multi;
+                $sids{$sid}{printed} = 1;
+                next RULELOOP;
+            }
+
+          # If this sid has not yet been printed and this is the place where
+          # the sid with the highest rev was, print the rule to the file.
+          # (There can be multiple totally different rules with the same sid
+          # and we don't want to put the wrong rule in the wrong place.
+            if (!exists($sids{$sid}{printed}) && $single eq $sids{$sid}{single}) {
+                print OUTFILE $multi;
+                $sids{$sid}{printed} = 1;
+            }
+        }
+
+        close(OUTFILE);
+    }
+
+    print STDERR "disabled $stats{disabled}, enabled $stats{enabled}, ".
+                 "modified $stats{modified}, total=$stats{total}\n"
+      unless ($config{quiet});
+
+  # Print warnings on attempt at enablesid/disablesid/localsid on non-existent
+  # rule if we're in verbose mode.
+    if ($config{verbose}) {
+        foreach my $sid (keys(%$enable_sid_ref)) {
+            warn("WARNING: attempt to use \"enablesid\" on non-existent SID $sid\n")
+              unless (exists($sids{$sid}));
+        }
+
+        foreach my $sid (keys(%$disable_sid_ref)) {
+            warn("WARNING: attempt to use \"disablesid\" on non-existent SID $sid\n")
+              unless (exists($sids{$sid}));
+        }
+
+        foreach my $sid (keys(%$local_sid_ref)) {
+            warn("WARNING: attempt to use \"localsid\" on non-existent SID $sid\n")
+              unless (exists($sids{$sid}));
+        }
+    }
+
+  # Print warnings on attempt at modifysid'ing non-existent stuff, unless quiet mode.
+    unless ($config{quiet}) {
+        my %new_files;
+        foreach my $file (sort(keys(%$newfiles_ref))) {
+            $new_files{basename($file)} = 1;
+        }
+
+        my %mod_tmp;
+        foreach my $mod_expr (@$modify_sid_ref) {
+            my ($type, $arg) = ($mod_expr->[2], $mod_expr->[3]);
+            $mod_tmp{$type}{$arg} = 1;
+        }
+
+        foreach my $sid (keys(%{$mod_tmp{sid}})) {
+            warn("WARNING: attempt to use \"modifysid\" on non-existent SID $sid\n")
+              unless (exists($sids{$sid}));
+        }
+
+        foreach my $file (keys(%{$mod_tmp{file}})) {
+            warn("WARNING: attempt to use \"modifysid\" on non-existent file $file\n")
+              unless(exists($new_files{$file}));
+        }
+    }
+
+  # Return total number of valid rules.
+    return ($stats{total});
+}
+
+
+
+# Process (modify/enable/disable) a rule as requested.
+sub process_rule($ $ $ $ $ $ $ $)
+{
+    my $modify_sid_ref  = shift;
+    my $disable_sid_ref = shift;
+    my $enable_sid_ref  = shift;
+    my $rule_ref        = shift;
+    my $sid             = shift;
+    my $stats_ref       = shift;
+    my $print_messages  = shift;
+    my $filename        = shift;
+
+  # Just for easier access.
+    my $single = $$rule_ref{single};
+    my $multi  = $$rule_ref{multi};
+
+  # Some rules may be commented out by default.
+  # Enable them if -e is specified (both single-line and multi-line,
+  # version, because we don't know which version one we're going to
+  # use below.
+  # Enable them if -e is specified.
+    if ($multi =~ /^#/ && $config{enable_all}) {
+        $multi  =~ s/^#*//;
+        $multi  =~ s/\n#*/\n/g;
+        $single =~ s/^#*//;
+        $$stats_ref{enabled}++;
+    }
+
+  # Modify rule if requested. For disablesid/enablesid we work
+  # on the multi-line version of the rule (if exists). For
+  # modifysid that's no good since we don't know where in the
+  # rule the trailing backslashes and newlines are going to be
+  # and we don't want them to affect the regexp.
+    MOD_EXP:foreach my $mod_expr (@$modify_sid_ref) {
+        my ($subst, $repl, $type, $arg) =
+          ($mod_expr->[0], $mod_expr->[1], $mod_expr->[2], $mod_expr->[3]);
+
+        my $print_modify_warnings = 0;
+        $print_modify_warnings = 1 if (!$config{super_quiet} && $print_messages && $type eq "sid");
+
+        if ($type eq "wildcard" || ($type eq "sid" && $sid eq $arg) ||
+          ($type eq "file" && $filename eq $arg)) {
+
+            if ($single =~ /$subst/si) {
+                print STDERR "Modifying rule, SID=$sid, filename=$filename, ".
+                             "match type=$type, subst=$subst, ".
+                             "repl=$repl\nBefore: $single"
+                  if ($print_messages && $config{verbose});
+
+
+              # If user specified a backreference but the regexp did not set $1 - don't modify rule.
+                if (!defined($1) && ($repl =~ /[^\\]\$\d+/ || $repl =~ /[^\\]\$\{\d+\}/
+                  || $repl =~ /^qq\/\$\d+/ || $repl =~ /^qq\/\$\{\d+\}/)) {
+                    warn("WARNING: SID $sid matches modifysid expression \"$subst\" but ".
+                         "backreference variable \$1 is undefined after match, ".
+                         "keeping original rule\n")
+                      if ($print_modify_warnings);
+                    next MOD_EXP;
+                }
+
+              # Do the substitution on the single-line version and put it
+              # back in $multi.
+                $single =~ s/$subst/$repl/eei;
+                $multi = $single;
+
+      	        print STDERR "After:  $single\n"
+                  if ($print_messages && $config{verbose});
+
+                $$stats_ref{modified}++;
+            } else {
+                if ($print_modify_warnings) {
+                    warn("WARNING: SID $sid does not match modifysid ".
+                         "expression \"$subst\", keeping original rule\n");
+                }
+            }
+        }
+    }
+
+  # Disable rule if requested and it's not already disabled.
+    if (exists($$disable_sid_ref{$sid}) && $multi !~ /^\s*#/) {
+        $multi = "#$multi";
+        $multi =~ s/\n([^#].+)/\n#$1/g;
+        $$stats_ref{disabled}++;
+    }
+
+  # Enable rule if requested and it's not already enabled.
+    if (exists($$enable_sid_ref{$sid}) && $multi =~ /^\s*#/) {
+        $multi =~ s/^#+//;
+        $multi =~ s/\n#+(.+)/\n$1/g;
+        $$stats_ref{enabled}++;
+    }
+
+    $$rule_ref{single} = $single;
+    $$rule_ref{multi}  = $multi;
+}
+
+
+
+# Setup rules hash.
+# Format for rules will be:     rh{old|new}{rules{filename}{sid} = single-line rule
+# Format for non-rules will be: rh{old|new}{other}{filename}     = array of lines
+# List of added files will be stored as rh{added_files}{filename}
+sub setup_rules_hash($ $)
+{
+    my $new_files_ref = shift;
+    my $output_dir    = shift;
+
+    my (%rh, %old_sids);
+
+    print STDERR "Setting up rules structures... "
+      unless ($config{quiet});
+
+    foreach my $file (sort(keys(%$new_files_ref))) {
+        warn("\nWARNING: downloaded rules file $file is empty\n")
+          if (!-s "$file" && $config{verbose});
+
+        open(NEWFILE, "<", "$file")
+          or clean_exit("could not open $file for reading: $!");
+        my @newfile = <NEWFILE>;
+        close(NEWFILE);
+
+      # From now on we don't care about the path, so remove it.
+	$file = basename($file);
+
+        my ($single, $multi, $nonrule, $msg, $sid);
+
+	while (get_next_entry(\@newfile, \$single, \$multi, \$nonrule, \$msg, \$sid)) {
+	    if (defined($single)) {
+  	        $rh{new}{rules}{"$file"}{"$sid"} = $single;
+	    } else {
+	        push(@{$rh{new}{other}{"$file"}}, $nonrule);
+	    }
+	}
+
+	# Also read in old (aka local) file if it exists.
+        # We do a sid dup check in these files.
+        if (-f "$output_dir/$file") {
+            open(OLDFILE, "<", "$output_dir/$file")
+              or clean_exit("could not open $output_dir/$file for reading: $!");
+	    my @oldfile = <OLDFILE>;
+            close(OLDFILE);
+
+	    while (get_next_entry(\@oldfile, \$single, \$multi, \$nonrule, undef, \$sid)) {
+	        if (defined($single)) {
+		    warn("\nWARNING: duplicate SID in your local rules, SID ".
+                         "$sid exists multiple times, you may need to fix this manually!\n")
+		      if (exists($old_sids{$sid}));
+
+	  	    $rh{old}{rules}{"$file"}{"$sid"} = $single;
+	  	    $old_sids{$sid}++;
+                } else {
+	            push(@{$rh{old}{other}{"$file"}}, $nonrule);
+                }
+            }
+        } else {
+	    $rh{added_files}{"$file"}++;
+        }
+    }
+
+    print STDERR "done.\n"
+      unless ($config{quiet});
+
+    return (%rh);
+}
+
+
+
+# Return lines that exist only in first array but not in second one.
+sub get_first_only($ $ $)
+{
+    my $first_only_ref = shift;
+    my $first_arr_ref  = shift;
+    my $second_arr_ref = shift;
+    my %arr_hash;
+
+    @arr_hash{@$second_arr_ref} = ();
+
+    foreach my $line (@$first_arr_ref) {
+
+      # Skip blank lines and CVS Id tags.
+        next unless ($line =~ /\S/);
+        next if     ($line =~ /^\s*#+\s*\$I\S:.+Exp\s*\$/);
+
+        push(@$first_only_ref, $line)
+          unless(exists($arr_hash{$line}));
+    }
+}
+
+
+
+# Backup files in output dir matching $config{update_files} into the backup dir.
+sub make_backup($ $)
+{
+    my $src_dir  = shift;    # dir with the rules to be backed up
+    my $dest_dir = shift;    # where to put the backup tarball
+
+    my ($sec, $min, $hour, $mday, $mon, $year) = (localtime)[0 .. 5];
+
+    my $date = sprintf("%4d%02d%02d-%02d%02d%02d",
+                       $year + 1900, $mon + 1, $mday, $hour, $min, $sec);
+
+    my $backup_tarball = "rules-backup-$date.tar";
+    my $backup_tmp_dir = File::Spec->catdir("$tmpdir", "rules-backup-$date");
+    my $dest_file      = File::Spec->catfile("$dest_dir", "$backup_tarball.gz");
+
+    print STDERR "Creating backup of old rules..."
+      unless ($config{quiet});
+
+    mkdir("$backup_tmp_dir", 0700)
+      or clean_exit("could not create temporary backup directory $backup_tmp_dir: $!");
+
+  # Copy all rules files from the rules dir to the temporary backup dir.
+    opendir(OLDRULES, "$src_dir")
+      or clean_exit("could not open directory $src_dir: $!");
+
+    while ($_ = readdir(OLDRULES)) {
+        next if (/^\.\.?$/);
+        if (/$config{update_files}/) {
+	    my $src_file = untaint_path("$src_dir/$_");
+            copy("$src_file", "$backup_tmp_dir/")
+              or warn("WARNING: could not copy $src_file to $backup_tmp_dir/: $!");
+	}
+    }
+
+    closedir(OLDRULES);
+
+  # Also backup the -U <file> (as "variable-file.conf") if specified.
+    if ($config{update_vars}) {
+        copy("$config{varfile}", "$backup_tmp_dir/variable-file.conf")
+          or warn("WARNING: could not copy $config{varfile} to $backup_tmp_dir: $!")
+    }
+
+    my $old_dir = untaint_path(File::Spec->rel2abs(File::Spec->curdir()));
+
+  # Change directory to $tmpdir (so we'll be right below the directory where
+  # we have our rules to be backed up).
+    chdir("$tmpdir") or clean_exit("could not change directory to $tmpdir: $!");
+
+    if ($config{use_external_bins}) {
+        clean_exit("tar command returned error when archiving backup files.\n")
+          if (system("tar","cf","$backup_tarball","rules-backup-$date"));
+
+        clean_exit("gzip command returned error when compressing backup file.\n")
+          if (system("gzip","$backup_tarball"));
+
+        $backup_tarball .= ".gz";
+
+    } else {
+        my $tar = Archive::Tar->new;
+        opendir(RULES, "rules-backup-$date")
+          or clean_exit("unable to open directory \"rules-backup-$date\": $!");
+
+        while ($_ = readdir(RULES)) {
+            next if (/^\.\.?$/);
+            $tar->add_files("rules-backup-$date/$_");
+        }
+
+        closedir(RULES);
+
+        $backup_tarball .= ".gz";
+
+      # Write tarball. Print stupid error message if it fails as
+      # we can't use $tar->error or Tar::error on all platforms.
+        $tar->write("$backup_tarball", 1);
+
+        clean_exit("could not create backup archive: tarball empty after creation\n")
+          unless (-s "$backup_tarball");
+    }
+
+  # Change back to old directory (so it will work with -b <directory> as either
+  # an absolute or a relative path.
+    chdir("$old_dir")
+      or clean_exit("could not change directory back to $old_dir: $!");
+
+    copy("$tmpdir/$backup_tarball", "$dest_file")
+      or clean_exit("unable to copy $tmpdir/$backup_tarball to $dest_file/: $!\n");
+
+    print STDERR " saved as $dest_file.\n"
+      unless ($config{quiet});
+}
+
+
+
+# Print the results.
+sub print_changes($ $)
+{
+    my $ch_ref = shift;
+    my $rh_ref = shift;
+
+    my ($sec, $min, $hour, $mday, $mon, $year) = (localtime)[0 .. 5];
+
+    my $date = sprintf("%4d%02d%02d %02d:%02d:%02d",
+                       $year + 1900, $mon + 1, $mday, $hour, $min, $sec);
+
+    print "\n[***] Results from Oinkmaster started $date [***]\n";
+
+  # Print new variables.
+    if ($config{update_vars}) {
+       if ($#{$$ch_ref{new_vars}} > -1) {
+            print "\n[*] New variables: [*]\n";
+            foreach my $var (@{$$ch_ref{new_vars}}) {
+                print "    $var";
+            }
+        } else {
+            print "\n[*] New variables: [*]\n    None.\n"
+              unless ($config{super_quiet});
+        }
+    }
+
+
+  # Print rules modifications.
+    print "\n[*] Rules modifications: [*]\n    None.\n"
+      if (!keys(%{$$ch_ref{rules}}) && !$config{super_quiet});
+
+  # Print added rules.
+    if (exists($$ch_ref{rules}{added})) {
+        print "\n[+++]          Added rules:          [+++]\n";
+        if ($config{summary_output}) {
+            print_summary_change(\%{$$ch_ref{rules}{added}}, $rh_ref);
+        } else {
+            print_changetype($PRINT_NEW, "Added to",
+                             \%{$$ch_ref{rules}{added}}, $rh_ref);
+        }
+    }
+
+  # Print enabled rules.
+    if (exists($$ch_ref{rules}{ena})) {
+        print "\n[+++]         Enabled rules:         [+++]\n";
+        if ($config{summary_output}) {
+            print_summary_change(\%{$$ch_ref{rules}{ena}}, $rh_ref);
+        } else {
+            print_changetype($PRINT_NEW, "Enabled in",
+                             \%{$$ch_ref{rules}{ena}}, $rh_ref);
+        }
+    }
+
+  # Print enabled + modified rules.
+    if (exists($$ch_ref{rules}{ena_mod})) {
+        print "\n[+++]  Enabled and modified rules:   [+++]\n";
+        if ($config{summary_output}) {
+            print_summary_change(\%{$$ch_ref{rules}{ena_mod}}, $rh_ref);
+        } else {
+   	    print_changetype($PRINT_BOTH, "Enabled and modified in",
+                             \%{$$ch_ref{rules}{ena_mod}}, $rh_ref);
+        }
+    }
+
+  # Print modified active rules.
+    if (exists($$ch_ref{rules}{mod_act})) {
+        print "\n[///]     Modified active rules:     [///]\n";
+
+        if ($config{summary_output}) {
+            print_summary_change(\%{$$ch_ref{rules}{mod_act}}, $rh_ref);
+        } else {
+            print_changetype($PRINT_BOTH, "Modified active in",
+                             \%{$$ch_ref{rules}{mod_act}}, $rh_ref);
+        }
+    }
+
+  # Print modified inactive rules.
+    if (exists($$ch_ref{rules}{mod_ina})) {
+        print "\n[///]    Modified inactive rules:    [///]\n";
+        if ($config{summary_output}) {
+            print_summary_change(\%{$$ch_ref{rules}{mod_ina}}, $rh_ref);
+        } else {
+            print_changetype($PRINT_BOTH, "Modified inactive in",
+                             \%{$$ch_ref{rules}{mod_ina}}, $rh_ref);
+        }
+    }
+
+  # Print disabled + modified rules.
+    if (exists($$ch_ref{rules}{dis_mod})) {
+        print "\n[---]  Disabled and modified rules:  [---]\n";
+        if ($config{summary_output}) {
+            print_summary_change(\%{$$ch_ref{rules}{dis_mod}}, $rh_ref);
+        } else {
+            print_changetype($PRINT_BOTH, "Disabled and modified in",
+                             \%{$$ch_ref{rules}{dis_mod}}, $rh_ref);
+        }
+    }
+
+  # Print disabled rules.
+    if (exists($$ch_ref{rules}{dis})) {
+        print "\n[---]         Disabled rules:        [---]\n";
+        if ($config{summary_output}) {
+            print_summary_change(\%{$$ch_ref{rules}{dis}}, $rh_ref);
+        } else {
+            print_changetype($PRINT_NEW, "Disabled in",
+                             \%{$$ch_ref{rules}{dis}}, $rh_ref);
+        }
+    }
+
+  # Print removed rules.
+    if (exists($$ch_ref{rules}{removed})) {
+        print "\n[---]         Removed rules:         [---]\n";
+        if ($config{summary_output}) {
+            print_summary_change(\%{$$ch_ref{rules}{removed}}, $rh_ref);
+        } else {
+            print_changetype($PRINT_OLD, "Removed from",
+                             \%{$$ch_ref{rules}{removed}}, $rh_ref);
+        }
+    }
+
+
+  # Print non-rule modifications.
+    print "\n[*] Non-rule line modifications: [*]\n    None.\n"
+      if (!keys(%{$$ch_ref{other}}) && !$config{super_quiet});
+
+  # Print added non-rule lines.
+    if (exists($$ch_ref{other}{added})) {
+        print "\n[+++]      Added non-rule lines:     [+++]\n";
+        foreach my $file (sort({uc($a) cmp uc($b)} keys(%{$$ch_ref{other}{added}}))) {
+            my $num = $#{$$ch_ref{other}{added}{$file}} + 1;
+            print "\n     -> Added to $file ($num):\n";
+            foreach my $line (@{$$ch_ref{other}{added}{$file}}) {
+                print "        $line";
+            }
+        }
+    }
+
+  # Print removed non-rule lines.
+    if (keys(%{$$ch_ref{other}{removed}}) > 0) {
+        print "\n[---]     Removed non-rule lines:    [---]\n";
+        foreach my $file (sort({uc($a) cmp uc($b)} keys(%{$$ch_ref{other}{removed}}))) {
+            my $num = $#{$$ch_ref{other}{removed}{$file}} + 1;
+            print "\n     -> Removed from $file ($num):\n";
+            foreach my $other (@{$$ch_ref{other}{removed}{$file}}) {
+	        print "        $other";
+            }
+        }
+    }
+
+
+  # Print list of added files.
+    if (keys(%{$$ch_ref{added_files}})) {
+        print "\n[+] Added files (consider updating your snort.conf to include them if needed): [+]\n\n";
+        foreach my $added_file (sort({uc($a) cmp uc($b)} keys(%{$$ch_ref{added_files}}))) {
+            print "    -> $added_file\n";
+        }
+    } else {
+        print "\n[*] Added files: [*]\n    None.\n"
+          unless ($config{super_quiet} || $config{summary_output});
+    }
+
+  # Print list of possibly removed files if requested.
+    if ($config{check_removed}) {
+        if (keys(%{$$ch_ref{removed_files}})) {
+            print "\n[-] Files possibly removed from the archive ".
+                  "(consider removing them from your snort.conf if needed): [-]\n\n";
+            foreach my $removed_file (sort({uc($a) cmp uc($b)} keys(%{$$ch_ref{removed_files}}))) {
+                print "    -> $removed_file\n";
+	    }
+        } else {
+             print "\n[*] Files possibly removed from the archive: [*]\n    None.\n"
+               unless ($config{super_quiet} || $config{summary_output});
+        }
+    }
+
+    print "\n";
+}
+
+
+
+# Helper for print_changes().
+sub print_changetype($ $ $ $)
+{
+    my $type   = shift;   # $PRINT_OLD|$PRINT_NEW|$PRINT_BOTH
+    my $string = shift;   # string to print before filename
+    my $ch_ref = shift;   # reference to an entry in the rules changes hash
+    my $rh_ref = shift;   # reference to rules hash
+
+    foreach my $file (sort({uc($a) cmp uc($b)} keys(%$ch_ref))) {
+        my $num = keys(%{$$ch_ref{$file}});
+        print "\n     -> $string $file ($num):\n";
+        foreach my $sid (keys(%{$$ch_ref{$file}})) {
+	    if ($type == $PRINT_OLD) {
+                print "        $$rh_ref{old}{rules}{$file}{$sid}"
+            } elsif ($type == $PRINT_NEW) {
+                print "        $$rh_ref{new}{rules}{$file}{$sid}"
+	    } elsif ($type == $PRINT_BOTH) {
+
+                my $old = $$rh_ref{old}{rules}{$file}{$sid};
+                my $new = $$rh_ref{new}{rules}{$file}{$sid};
+
+                if ($config{minimize_diff}) {
+                    my ($old, $new) = minimize_diff($old, $new);
+                    print "\n        old SID $sid: $old";
+                    print "        new SID $sid: $new";
+                } else {
+                    print "\n        old: $old";
+                    print "        new: $new";
+                }
+	    }
+        }
+    }
+}
+
+
+
+# Print changes in bmc style, i.e. only sid and msg, no full details.
+sub print_summary_change($ $)
+{
+    my $ch_ref = shift;   # reference to an entry in the rules changes hash
+    my $rh_ref = shift;   # reference to rules hash
+
+    my (@sids, %sidmap);
+
+    print "\n";
+
+  # First get all the sids (may be spread across multiple files.
+    foreach my $file (keys(%$ch_ref)) {
+        foreach my $sid (keys(%{$$ch_ref{$file}})) {
+            push(@sids, $sid);
+            if (exists($$rh_ref{new}{rules}{$file}{$sid})) {
+                $sidmap{$sid}{rule} = $$rh_ref{new}{rules}{$file}{$sid};
+            } else {
+                $sidmap{$sid}{rule} = $$rh_ref{old}{rules}{$file}{$sid};
+            }
+            $sidmap{$sid}{file} = $file;
+        }
+    }
+
+  # Print rules, sorted by sid.
+    foreach my $sid (sort {$a <=> $b} (@sids)) {
+        my @rule = $sidmap{$sid}{rule};
+        my $file = $sidmap{$sid}{file};
+	get_next_entry(\@rule, undef, undef, undef, \(my $msg), undef);
+        printf("%8d - %s (%s)\n", $sid, $msg, $file);
+    }
+
+    print "\n";
+}
+
+
+
+# Compare the new rules to the old ones.
+sub get_changes($ $ $)
+{
+    my $rh_ref        = shift;
+    my $new_files_ref = shift;
+    my $rules_dir     = shift;
+    my %changes;
+
+    print STDERR "Comparing new files to the old ones... "
+      unless ($config{quiet});
+
+  # We have the list of added files (without full path) in $rh_ref{added_files}
+  # but we'd rather want to have it in $changes{added_files} now.
+    $changes{added_files} = $$rh_ref{added_files};
+
+  # New files are also regarded as modified since we want to update
+  # (i.e. add) those as well. Here we want them with full path.
+    foreach my $file (keys(%{$changes{added_files}})) {
+        $changes{modified_files}{"$tmpdir/$rules_dir/$file"}++;
+    }
+
+  # Add list of possibly removed files if requested.
+    if ($config{check_removed}) {
+        opendir(OLDRULES, "$config{output_dir}")
+          or clean_exit("could not open directory $config{output_dir}: $!");
+
+        while ($_ = readdir(OLDRULES)) {
+            next if (/^\.\.?$/);
+            $changes{removed_files}{"$_"} = 1
+              if (/$config{update_files}/ && 
+                !exists($config{file_ignore_list}{$_}) &&
+                !-e "$tmpdir/$rules_dir/$_");
+        }
+
+        closedir(OLDRULES);
+    }
+
+  # For each new rules file...
+    FILELOOP:foreach my $file_w_path (sort(keys(%$new_files_ref))) {
+        my $file = basename($file_w_path);
+
+      # Skip comparison if it's an added file.
+        next FILELOOP if (exists($$rh_ref{added_files}{$file}));
+
+      # For each sid in the new file...
+        foreach my $sid (keys(%{$$rh_ref{new}{rules}{$file}})) {
+            my $new_rule = $$rh_ref{new}{rules}{$file}{$sid};
+
+              # Sid also exists in the old file?
+                if (exists($$rh_ref{old}{rules}{$file}{$sid})) {
+                    my $old_rule = $$rh_ref{old}{rules}{$file}{$sid};
+
+                  # Are they identical?
+		    unless ($new_rule eq $old_rule) {
+                        $changes{modified_files}{$file_w_path}++;
+
+                      # Find out in which way the rules are different.
+                        if ("#$old_rule" eq $new_rule) {
+ 	                    $changes{rules}{dis}{$file}{$sid}++;
+                        } elsif ($old_rule eq "#$new_rule") {
+ 	                    $changes{rules}{ena}{$file}{$sid}++;
+                        } elsif ($old_rule =~ /^\s*#/ && $new_rule !~ /^\s*#/) {
+ 	                    $changes{rules}{ena_mod}{$file}{$sid}++;
+                        } elsif ($old_rule !~ /^\s*#/ && $new_rule =~ /^\s*#/) {
+ 	                    $changes{rules}{dis_mod}{$file}{$sid}++;
+                        } elsif ($old_rule =~ /^\s*#/ && $new_rule =~ /^\s*#/) {
+ 	                    $changes{rules}{mod_ina}{$file}{$sid}++;
+                        } else {
+ 	                    $changes{rules}{mod_act}{$file}{$sid}++;
+	  	        }
+
+		    }
+	        } else {    # sid not found in old file, i.e. it's added
+                    $changes{modified_files}{$file_w_path}++;
+  	            $changes{rules}{added}{$file}{$sid}++;
+	        }
+        } # foreach sid
+
+      # Check for removed rules, i.e. sids that exist in the old file but
+      # not in the new one.
+        foreach my $sid (keys(%{$$rh_ref{old}{rules}{$file}})) {
+            unless (exists($$rh_ref{new}{rules}{$file}{$sid})) {
+                $changes{modified_files}{$file_w_path}++;
+	        $changes{rules}{removed}{$file}{$sid}++;
+            }
+        }
+
+      # Check for added non-rule lines.
+        get_first_only(\my @added,
+                       \@{$$rh_ref{new}{other}{$file}},
+                       \@{$$rh_ref{old}{other}{$file}});
+
+        if (scalar(@added)) {
+            @{$changes{other}{added}{$file}} = @added;
+            $changes{modified_files}{$file_w_path}++;
+        }
+
+      # Check for removed non-rule lines.
+        get_first_only(\my @removed,
+                       \@{$$rh_ref{old}{other}{$file}},
+                       \@{$$rh_ref{new}{other}{$file}});
+
+        if (scalar(@removed)) {
+            @{$changes{other}{removed}{$file}} = @removed;
+            $changes{modified_files}{$file_w_path}++;
+        }
+
+    } # foreach new file
+
+    print STDERR "done.\n" unless ($config{quiet});
+
+    return (%changes);
+}
+
+
+
+# Simply copy the modified rules files to the output directory.
+sub update_rules($ @)
+{
+    my $dst_dir        = shift;
+    my @modified_files = @_;
+
+    print STDERR "Updating local rules files... "
+      if (!$config{quiet} || $config{interactive});
+
+    foreach my $file_w_path (@modified_files) {
+        copy("$file_w_path", "$dst_dir")
+          or clean_exit("could not copy $file_w_path to $dst_dir: $!");
+    }
+
+    print STDERR "done.\n"
+      if (!$config{quiet} || $config{interactive});
+}
+
+
+# Simply copy rules files from one dir to another.
+# Links are not allowed.
+sub copy_rules($ $)
+{
+    my $src_dir = shift;
+    my $dst_dir = shift;
+
+    print STDERR "Copying rules from $src_dir... "
+      if (!$config{quiet} || $config{interactive});
+
+    opendir(SRC_DIR, $src_dir)
+      or clean_exit("could not open directory $src_dir: $!");
+
+    my $num_files = 0;
+    while ($_ = readdir(SRC_DIR)) {
+        next if (/^\.\.?$/ || exists($config{file_ignore_list}{$_})
+          || !/$config{update_files}/);
+
+      my $src_file = untaint_path("$src_dir/$_");
+
+      # Make sure it's a regular file.
+        unless (-f "$src_file" && !-l "$src_file") {
+            closedir(SRC_DIR);
+            clean_exit("\"$src_file\" is not a regular file.")
+        }
+
+        unless (copy($src_file, $dst_dir)) {
+            closedir(SRC_DIR);
+            clean_exit("could not copy \"$src_file\" to \"$dst_dir\"/: $!");
+        }
+        $num_files++;
+    }
+
+    closedir(SRC_DIR);
+
+    print STDERR "$num_files files copied.\n"
+      if (!$config{quiet} || $config{interactive});
+}
+
+
+
+# Return true if file is in PATH and is executable.
+sub is_in_path($)
+{
+    my $file = shift;
+
+    foreach my $dir (File::Spec->path()) {
+        if ((-f "$dir/$file" && -x "$dir/$file")
+          || (-f "$dir/$file.exe" && -x "$dir/$file.exe")) {
+            print STDERR "Found $file binary in $dir\n"
+              if ($config{verbose});
+            return (1);
+        }
+    }
+
+    return (0);
+}
+
+
+
+# get_next_entry() will parse the array referenced in the first arg
+# and return the next entry. The array should contain a rules file,
+# and the returned entry will be removed from the array.
+# An entry is one of:
+# - single-line rule (put in 2nd ref)
+# - multi-line rule (put in 3rd ref)
+# - non-rule line (put in 4th ref)
+# If the entry is a multi-line rule, its single-line version is also
+# returned (put in the 2nd ref).
+# If it's a rule, the msg string will be put in 4th ref and sid in 5th.
+sub get_next_entry($ $ $ $ $ $)
+{
+    my $arr_ref     = shift;
+    my $single_ref  = shift;
+    my $multi_ref   = shift;
+    my $nonrule_ref = shift;
+    my $msg_ref     = shift;
+    my $sid_ref     = shift;
+
+    undef($$single_ref);
+    undef($$multi_ref);
+    undef($$nonrule_ref);
+    undef($$msg_ref);
+    undef($$sid_ref);
+
+    my $line = shift(@$arr_ref) || return(0);
+    my $disabled = 0;
+    my $broken   = 0;
+
+    chomp($line);
+    $line .= "\n";
+
+  # Possible beginning of multi-line rule?
+    if ($line =~ /$MULTILINE_RULE_REGEXP/oi) {
+        $$single_ref = $line;
+        $$multi_ref  = $line;
+
+        $disabled = 1 if ($line =~ /^\s*#/);
+
+      # Keep on reading as long as line ends with "\".
+        while (!$broken && $line =~ /\\\s*\n$/) {
+
+          # Remove trailing "\" and newline for single-line version.
+            $$single_ref =~ s/\\\s*\n//;
+
+          # If there are no more lines, this can not be a valid multi-line rule.
+            if (!($line = shift(@$arr_ref))) {
+
+                warn("\nWARNING: got EOF while parsing multi-line rule: $$multi_ref\n")
+                  if ($config{verbose});
+
+                @_ = split(/\n/, $$multi_ref);
+
+                undef($$multi_ref);
+                undef($$single_ref);
+
+              # First line of broken multi-line rule will be returned as a non-rule line.
+                $$nonrule_ref = shift(@_) . "\n";
+                $$nonrule_ref =~ s/\s*\n$/\n/;    # remove trailing whitespaces
+
+              # The rest is put back to the array again.
+                foreach $_ (reverse((@_))) {
+                    unshift(@$arr_ref, "$_\n");
+                }
+
+                return (1);   # return non-rule
+            }
+
+          # Multi-line continuation.
+            $$multi_ref .= $line;
+
+          # If there are non-comment lines in the middle of a disabled rule,
+          # mark the rule as broken to return as non-rule lines.
+            if ($line !~ /^\s*#/ && $disabled) {
+                $broken = 1;
+            } elsif ($line =~ /^\s*#/ && !$disabled) {
+                # comment line (with trailing slash) in the middle of an active rule - ignore it
+            } else {
+                $line =~ s/^\s*#*\s*//;  # remove leading # in single-line version
+                $$single_ref .= $line;
+            }
+
+        } # while line ends with "\"
+
+      # Single-line version should now be a valid rule.
+      # If not, it wasn't a valid multi-line rule after all.
+        if (!$broken && parse_singleline_rule($$single_ref, $msg_ref, $sid_ref)) {
+
+            $$single_ref =~ s/^\s*//;     # remove leading whitespaces
+            $$single_ref =~ s/^#+\s*/#/;  # remove whitespaces next to leading #
+            $$single_ref =~ s/\s*\n$/\n/; # remove trailing whitespaces
+
+            $$multi_ref  =~ s/^\s*//;
+            $$multi_ref  =~ s/\s*\n$/\n/;
+            $$multi_ref  =~ s/^#+\s*/#/;
+
+            return (1);   # return multi
+
+      # Invalid multi-line rule.
+        } else {
+            warn("\nWARNING: invalid multi-line rule: $$single_ref\n")
+              if ($config{verbose} && $$multi_ref !~ /^\s*#/);
+
+            @_ = split(/\n/, $$multi_ref);
+
+            undef($$multi_ref);
+            undef($$single_ref);
+
+          # First line of broken multi-line rule will be returned as a non-rule line.
+            $$nonrule_ref = shift(@_) . "\n";
+            $$nonrule_ref =~ s/\s*\n$/\n/;   # remove trailing whitespaces
+
+          # The rest is put back to the array again.
+            foreach $_ (reverse((@_))) {
+                unshift(@$arr_ref, "$_\n");
+            }
+
+            return (1);   # return non-rule
+        }
+
+  # Check if it's a regular single-line rule.
+    } elsif (parse_singleline_rule($line, $msg_ref, $sid_ref)) {
+        $$single_ref = $line;
+        $$single_ref =~ s/^\s*//;
+        $$single_ref =~ s/^#+\s*/#/;
+        $$single_ref =~ s/\s*\n$/\n/;
+
+        return (1);   # return single
+
+  # Non-rule line.
+    } else {
+
+      # Do extra check and warn if it *might* be a rule anyway,
+      # but that we just couldn't parse for some reason.
+        warn("\nWARNING: line may be a rule but it could not be parsed ".
+             "(missing sid?): $line\n")
+          if ($config{verbose} && $line =~ /^\s*alert .+msg\s*:\s*".+"\s*;/);
+
+        $$nonrule_ref = $line;
+        $$nonrule_ref =~ s/\s*\n$/\n/;
+
+        return (1);   # return non-rule
+    }
+}
+
+
+
+# Look for variables that exist in dist var files but not in local var file.
+sub get_new_vars($ $ $ $)
+{
+    my $ch_ref             = shift;
+    my $dist_var_files_ref = shift;
+    my $local_var_file     = shift;
+    my $url_tmpdirs_ref    = shift;
+
+    my %new_vars;
+    my (%old_vars, %dist_var_files, %found_dist_var_files);
+    my $confs_found = 0;
+
+
+  # Warn in case we can't find a specified dist file.
+    foreach my $dir (@$url_tmpdirs_ref) {
+        foreach my $dist_var_file (@$dist_var_files_ref) {
+            if (-e "$dir/$dist_var_file") {
+                $found_dist_var_files{$dist_var_file} = 1;
+                $confs_found++;
+            }
+        }
+    }
+
+    foreach my $dist_var_file (@$dist_var_files_ref) {
+        unless (exists($found_dist_var_files{$dist_var_file})) {
+            warn("WARNING: did not find variable file \"$dist_var_file\" in ".
+                 "downloaded archive(s)\n")
+              unless($config{quiet});
+        }
+    }
+
+    unless ($confs_found) {
+        unless ($config{quiet}) {
+            warn("WARNING: no variable files found in downloaded archive(s), ".
+                 "aborting check for new variables\n");
+            return;
+        }
+    }
+
+  # Read in variable names from old (target) var file.
+    open(LOCAL_VAR_FILE, "<", "$local_var_file")
+      or clean_exit("could not open $local_var_file for reading: $!");
+
+    my @local_var_conf = <LOCAL_VAR_FILE>;
+
+    foreach $_ (join_multilines(\@local_var_conf)) {
+        $old_vars{lc($1)}++ if (/$VAR_REGEXP/i);
+    }
+
+    close(LOCAL_VAR_FILE);
+
+  # Read in variables from new file(s).
+    foreach my $dir (@$url_tmpdirs_ref) {
+        foreach my $dist_var_file (@$dist_var_files_ref) {
+            my $conf = "$dir/$dist_var_file";
+            if (-e "$conf") {
+                my $num_new = 0;
+                print STDERR "Checking downloaded $dist_var_file for new variables... "
+                  unless ($config{quiet});
+
+                open(DIST_CONF, "<", "$conf")
+                  or clean_exit("could not open $conf for reading: $!");
+                my @dist_var_conf = <DIST_CONF>;
+                close(DIST_CONF);
+
+                foreach $_ (join_multilines(\@dist_var_conf)) {
+                    if (/$VAR_REGEXP/i && !exists($old_vars{lc($1)})) {
+                        my ($varname, $varval) = (lc($1), $2);
+                        if (exists($new_vars{$varname})) {
+                            warn("\nWARNING: new variable \"$varname\" is defined multiple ".
+                                 "times in downloaded files\n");
+                        }
+                        s/^\s*//;
+                        push(@{$$ch_ref{new_vars}}, "$_\n");
+                        $new_vars{$varname} = $varval;
+                        $num_new++;
+                    }
+                }
+
+                close(DIST_CONF);
+                print STDERR "$num_new new found.\n"
+                  unless ($config{quiet});
+            }
+        }
+    }
+}
+
+
+
+# Add new variables to local snort.conf.
+sub add_new_vars($ $)
+{
+    my $ch_ref      = shift;
+    my $varfile     = shift;
+    my $tmp_varfile = "$tmpdir/tmp_varfile.conf";
+    my $new_content;
+
+    return unless ($#{$changes{new_vars}} > -1);
+
+    print STDERR "Adding new variables to $varfile... "
+      unless ($config{quiet});
+
+    open(OLD_LOCAL_CONF, "<", "$varfile")
+      or clean_exit("could not open $varfile for reading: $!");
+    my @old_content = <OLD_LOCAL_CONF>;
+    close(OLD_LOCAL_CONF);
+
+    open(NEW_LOCAL_CONF, ">", "$tmp_varfile")
+      or clean_exit("could not open $tmp_varfile for writing: $!");
+
+    my @old_vars = grep(/$VAR_REGEXP/i, @old_content);
+
+
+  # If any vars exist in old file, put new vars right after them.
+    if ($#old_vars > -1) {
+        while ($_ = shift(@old_content)) {
+            print NEW_LOCAL_CONF $_;
+            last if ($_ eq $old_vars[$#old_vars]);
+        }
+    }
+
+    print NEW_LOCAL_CONF @{$changes{new_vars}};
+    print NEW_LOCAL_CONF @old_content;
+
+    close(NEW_LOCAL_CONF);
+
+    clean_exit("could not copy $tmp_varfile to $varfile: $!")
+      unless (copy("$tmp_varfile", "$varfile"));
+
+    print STDERR "done.\n"
+      unless ($config{quiet});
+}
+
+
+
+# Convert msdos style path to cygwin style, e.g.
+# c:\foo => /cygdrive/c/foo
+sub msdos_to_cygwin_path($)
+{
+    my $path_ref = shift;
+
+    if ($$path_ref =~ /^([a-zA-Z]):[\/\\](.*)/) {
+        my ($drive, $dir) = ($1, $2);
+	$dir =~ s/\\/\//g;
+	$$path_ref = "/cygdrive/$drive/$dir";
+        return (1);
+    }
+
+    return (0);
+}
+
+
+
+# Parse and process a modifysid expression.
+# Return 1 if valid, or otherwise 0.
+sub parse_mod_expr($ $ $ $)
+{
+    my $mod_list_ref = shift;  # where to store valid entries
+    my $sid_arg_list = shift;  # comma-separated list of SIDs/files or wildcard
+    my $subst        = shift;  # regexp to look for
+    my $repl         = shift;  # regexp to replace it with
+
+    my @tmp_mod_list;
+
+    $sid_arg_list =~ s/\s+$//;
+
+    foreach my $sid_arg (split(/\s*,\s*/, $sid_arg_list)) {
+        my $type = "";
+
+        $type = "sid"      if ($sid_arg =~ /^\d+$/);
+        $type = "file"     if ($sid_arg =~ /^\S+.*\.\S+$/);
+        $type = "wildcard" if ($sid_arg eq "*");
+
+        return (0) unless ($type);
+
+      # Sanity check to make sure user escaped at least all the "$" in $subst.
+        if ($subst =~ /[^\\]\$./ || $subst =~ /^\$/) {
+            warn("WARNING: unescaped \$ in expression \"$subst\", all special ".
+                 "characters must be escaped\n");
+            return (0);
+        }
+
+      # Only allow backreference variables. The check should at least catch some user typos.
+        if (($repl =~ /[^\\]\$(\D.)/ && $1 !~ /{\d/) || $repl =~ /[^\\]\$$/
+          || ($repl =~ /^\$(\D.)/ && $1 !~ /{\d/)) {
+            warn("WARNING: illegal replacement expression \"$repl\": unescaped \$ ".
+                 "that isn't a backreference\n");
+            return (0);
+        }
+
+      # Don't permit unescaped @.
+        if ($repl =~ /[^\\]\@/ || $repl =~ /^\@/) {
+            warn("WARNING: illegal replacement expression \"$repl\": unescaped \@\n");
+            return (0);
+        }
+
+      # Make sure the regexp is valid.
+        my $repl_qq = "qq/$repl/";
+        my $dummy   = "foo";
+
+        eval {
+            $dummy =~ s/$subst/$repl_qq/ee;
+        };
+
+      # We should probably check for warnings as well as errors...
+        if ($@) {
+            warn("Invalid regexp: $@");
+            return (0);
+        }
+
+        push(@tmp_mod_list, [$subst, $repl_qq, $type, $sid_arg]);
+    }
+
+  # If we come this far, all sids and the regexp were parsed successfully, so
+  # append them to real mod list array.
+    foreach my $mod_entry (@tmp_mod_list) {
+        push(@$mod_list_ref, $mod_entry);
+    }
+
+    return (1);
+}
+
+
+
+# Untaint a path. Die if it contains illegal chars.
+sub untaint_path($)
+{
+    my $path      = shift;
+    my $orig_path = $path;
+
+    return $path unless ($config{use_path_checks});
+
+    (($path) = $path =~ /^([$OK_PATH_CHARS]+)$/)
+      or clean_exit("illegal character in path/filename ".
+                    "\"$orig_path\", allowed are $OK_PATH_CHARS\n".
+                    "Fix this or set use_path_checks=0 in oinkmaster.conf ".
+                    "to disable this check completely if it is too strict.\n");
+
+    return ($path);
+}
+
+
+
+# Ask user to approve changes. Return 1 for yes, 0 for no.
+sub approve_changes()
+{
+    my $answer = "";
+
+    while ($answer !~ /^[yn]/i) {
+        print "Do you approve these changes? [Yn] ";
+        $answer = <STDIN>;
+        $answer = "y" unless ($answer =~ /\S/);
+    }
+
+    return ($answer =~ /^y/i);
+}
+
+
+
+# Remove common leading and trailing stuff from two rules.
+sub minimize_diff($ $)
+{
+    my $old_rule = shift;
+    my $new_rule = shift;
+
+    my $original_old = $old_rule;
+    my $original_new = $new_rule;
+
+  # Additional chars to print next to the diffing part.
+    my $additional_chars = 20;
+
+  # Remove the rev keyword from the rules, as it often
+  # makes the whole diff minimizing useless.
+    $old_rule =~ s/\s*\b(rev\s*:\s*\d+\s*;)\s*//;
+    my $old_rev = $1;
+
+    $new_rule =~ s/\s*\b(rev\s*:\s*\d+\s*;)\s*//;
+    my $new_rev = $1;
+
+  # If rev was the only thing that changed, we want to restore the rev
+  # before continuing so we don't remove common stuff from rules that
+  # are identical.
+    if ($old_rule eq $new_rule) {
+        $old_rule = $original_old;
+        $new_rule = $original_new;
+    }
+
+  # Temporarily remove possible leading # so it works nicely
+  # with modified rules that are also being either enabled or disabled.
+    my $old_is_disabled = 0;
+    my $new_is_disabled = 0;
+
+    $old_is_disabled = 1 if ($old_rule =~ s/^#//);
+    $new_is_disabled = 1 if ($new_rule =~ s/^#//);
+
+  # Go forward char by char until they aren't equeal.
+  # $i will bet set to the index where they diff.
+    my @old = split(//, $old_rule);
+    my @new = split(//, $new_rule);
+
+    my $i = 0;
+    while ($i <= $#old && $i <= $#new && $old[$i] eq $new[$i]) {
+        $i++;
+    }
+
+  # Now same thing but backwards.
+  # $j will bet set to the index where they diff.
+    @old = reverse(split(//, $old_rule));
+    @new = reverse(split(//, $new_rule));
+
+    my $j = 0;
+    while ($j <= $#old && $j <= $#new && $old[$j] eq $new[$j]) {
+        $j++;
+    }
+
+  # Print some additional chars on either side, if there is room for it.
+    $i -= $additional_chars;
+    $i = 0 if ($i < 0);
+
+    $j = -$j + $additional_chars;
+    $j = 0 if ($j > -1);
+
+    my ($old, $new);
+
+  # Print entire rules (i.e. they can not be shortened).
+    if (!$i && !$j) {
+        $old = $old_rule;
+        $new = $new_rule;
+
+  # Leading and trailing stuff can be removed.
+    } elsif ($i && $j) {
+        $old = "..." . substr($old_rule, $i, $j) . "...";
+        $new = "..." . substr($new_rule, $i, $j) . "...";
+
+  # Trailing stuff can be removed.
+    } elsif (!$i && $j) {
+        $old = substr($old_rule, $i, $j) . "...";
+        $new = substr($new_rule, $i, $j) . "...";
+
+  # Leading stuff can be removed.
+    } elsif ($i && !$j) {
+        $old = "..." . substr($old_rule, $i);
+        $new = "..." . substr($new_rule, $i);
+    }
+
+    chomp($old, $new);
+    $old .= "\n";
+    $new .= "\n";
+
+  # Restore possible leading # now.
+    $old = "#$old" if ($old_is_disabled);
+    $new = "#$new" if ($new_is_disabled);
+
+    return ($old, $new);
+}
+
+
+
+# Check a string and return 1 if it's a valid single-line snort rule.
+# Msg string is put in second arg, sid in third (those are the only
+# required keywords, besides the leading rule actions).
+sub parse_singleline_rule($ $ $)
+{
+    my $line    = shift;
+    my $msg_ref = shift;
+    my $sid_ref = shift;
+
+    undef($$msg_ref);
+    undef($$sid_ref);
+
+    if ($line =~ /$SINGLELINE_RULE_REGEXP/oi) {
+
+        if ($line =~ /\bmsg\s*:\s*"(.+?)"\s*;/i) {
+            $$msg_ref = $1;
+        } else {
+            return (0);
+        }
+
+        if ($line =~ /\bsid\s*:\s*(\d+)\s*;/i) {
+            $$sid_ref = $1;
+        } else {
+            return (0);
+        }
+
+        return (1);
+    }
+
+    return (0);
+}
+
+
+
+# Merge multiline directives in an array by simply removing traling backslashes.
+sub join_multilines($)
+{
+    my $multiline_conf_ref = shift;
+    my $joined_conf = "";
+
+    foreach $_ (@$multiline_conf_ref) {
+        s/\\\s*\n$//;
+        $joined_conf .= $_;
+    }
+
+    return (split/\n/, $joined_conf);
+}
+
+
+
+# Catch SIGINT.
+sub catch_sigint()
+{
+    $SIG{INT} = 'IGNORE';
+    print STDERR "\nInterrupted, cleaning up.\n";
+    sleep(1);
+    clean_exit("interrupted by signal");
+}
+
+
+
+# Remove temporary directory and exit.
+# If a non-empty string is given as argument, it will be regarded
+# as an error message and we will use die() with the message instead
+# of just exit(0).
+sub clean_exit($)
+{
+    my $err_msg = shift;
+
+    $SIG{INT} = 'DEFAULT';
+
+    if (defined($tmpdir) && -d "$tmpdir") {
+        chdir(File::Spec->rootdir());
+        rmtree("$tmpdir", 0, 1);
+        undef($tmpdir);
+    }
+
+    if (!defined($err_msg) || $err_msg eq "") {
+        exit(0);
+    } else {
+	chomp($err_msg);
+        die("\n$0: Error: $err_msg\n\nOink, oink. Exiting...\n");
+    }
+}
+
+
+
+#### EOF ####