Enable and use the warnings core module.
[people/stevee/guardian.git] / guardian
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1#!/usr/bin/perl
2###############################################################################
3# #
4# IPFire.org - A linux based firewall #
5# Copyright (C) 2015 IPFire Development Team #
6# #
7# This program is free software: you can redistribute it and/or modify #
8# it under the terms of the GNU General Public License as published by #
9# the Free Software Foundation, either version 3 of the License, or #
10# (at your option) any later version. #
11# #
12# This program is distributed in the hope that it will be useful, #
13# but WITHOUT ANY WARRANTY; without even the implied warranty of #
14# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the #
15# GNU General Public License for more details. #
16# #
17# You should have received a copy of the GNU General Public License #
18# along with this program. If not, see <http://www.gnu.org/licenses/>. #
19# #
20###############################################################################
21
22use strict;
23use threads;
24use threads::shared;
45bf2a03 25use Getopt::Long;
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26use Thread::Queue;
27use Linux::Inotify2;
01147a7e 28use Time::HiRes qw[ time sleep ];
88d9af2c 29
45bf2a03 30require Guardian::Config;
88d9af2c 31require Guardian::Parser;
6abac3d4 32require Guardian::Socket;
88d9af2c 33
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34use warnings;
35
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36# Define version.
37my $version ="2.0";
38
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39# Array to store the monitored logfiles.
40my @monitored_files = (
41 "/var/log/snort/alert",
42);
43
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44# Get and store the given command line arguments in a hash.
45my %cmdargs = ();
46
47&GetOptions (\%cmdargs,
48 'foreground|f',
49 'config|c=s',
50 'help|h',
51 'version|v',
52);
53
54# Show help / version information.
55if (defined($cmdargs{"help"})) {
56 print "Guardian $version \n";
57 print "Usage: guardian <optional arguments>\n";
58 print " -c, --config\t\tspecifiy a configuration file other than the default (/etc/guardian/guardian.conf)\n";
59 print " -f, --foreground\trun in the foreground (doesn't fork, any output goes to STDOUT)\n";
60 print " -h, --help\t\tshows this help\n";
61 print " -v, --version\t\tdisplay programm version and exit.\n";
62 exit;
63} elsif (defined($cmdargs{"version"})) {
64 print "Guardian $version \n";
65 exit;
66}
67
68# Read-in the configuration file and store the settings.
69# Push the may be given config file argument.
70my %mainsettings = &Guardian::Config::UseConfig($cmdargs{"config"});
71
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72# Create the main queue. It is used to store and process all events which are
73# reported and enqueued by the worker threads.
74my $queue :shared = new Thread::Queue or die "Could not create new, empty queue. $!\n";;
75
76# Call Init function to initzialize guardian.
77&Init();
78
79# Infinite main loop, which processes all queued events.
80while(1) {
81 # Get the amount of elements in our queue.
82 # "undef" will be returned if it is empty.
83 my $current_events = $queue->pending();
84
85 # If there is at least one element enqued
86 if($current_events > 0) {
87 # Grab the data of the top enqueued event.
88 my $event = $queue->peek();
89
90 print "Got event: $event\n";
91
92 # Drop processed event from queue.
93 $queue->dequeue();
94 }
95
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96 # Sleep 10ms to reduce the load of the main process.
97 sleep(0.01);
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98}
99
100#
101## Init function.
102#
103## This function contains code which has to be executed while guardian
104## is starting.
105#
106sub Init () {
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107 # Setup signal handler.
108 &SignalHandler();
109
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110 # Setup IPC mechanism via Socket in an own thread.
111 threads->create(\&Socket);
112
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113 # Loop through the array of which files should be monitored and
114 # create a worker thread for each single one.
115 foreach my $monitored_file (@monitored_files) {
116 # Check if the file exists and is readable.
117 if (-r "$monitored_file") {
118 # Create worker thread for the file.
119 threads->create(\&Worker,$monitored_file);
120 }
121 }
122}
123
124#
125## Worker function.
126#
127## This function is responsible for monitoring modifications of the given logfile,
128## read them and pass them to the message parser.
129#
130## To get file modifications the inotify subsystem of the linux kernel is used.
131#
132## In order to prevent from permanently read and keep files opened, or dealing
133## with huge logfiles, at initialization time of the worker process, the file will
134## be opened once and the cursor position of the end of file (EOF) get stored. When
135## reading any newly added lines from the file, we directly can jump to the last
136## known position and get these lines. Afterwards, we store the current curser position
137## again, so we can do it in this way over and over again.
138#
139## All read lines get stored in an array, which will be passed to the Parser.
140#
141## If any response (action) from the parser get recieved, it will be put into the
142## shared event queue.
143#
144sub Worker ($) {
145 my $file = @_[0];
146
147 # Get the fileposition.
148 my $fileposition = &Init_fileposition("$file");
149
150 # Create inotify watcher.
151 my $watcher = new Linux::Inotify2 or die "Could not use inotify. $!\n";
152
153 # Monitor the specified file.
154 $watcher->watch("$file", IN_MODIFY) or die "Could not monitor $file. $!\n";
155
156 # Get all notifications.
157 while ($watcher->read) {
158 my @message = ();
159
160 # Open the file.
161 open (FILE, $file) or die "Could not open $file. $!\n";
162
163 # Seek to the last known position.
164 seek (FILE, $fileposition, 0);
165
166 # Get the log message.
167 while (my $line = <FILE>) {
168 # Remove any newlines.
169 chomp $line;
170
171 # Add all lines to the message array.
172 push (@message, $line);
173 }
174
175 # Update fileposition.
176 $fileposition = tell(FILE);
177
178 # Close file.
179 close(FILE);
180
181 # Send filename and message to the parser,
182 # which will return if an action has to be performed.
183 my @action = &Guardian::Parser::Parser("$file", @message);
184
185 # Send the action to the main process and put it into
186 # the queue.
187 if (@action) {
188 # Lock the queue.
189 lock($queue);
190
191 # Put the required action into the queue.
192 $queue->enqueue(@action);
193 }
194 }
195}
196
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197#
198## Socket function.
199#
200## This function uses the Socket module to create and listen to an UNIX socket.
201## It automatically accepts all incomming connections and pass the recieved
202## data messages to the the Message_Parser function which is also part of the
203## socket module.
204#
205## If a valid command has been sent through the socket, the corresponding event
206## will be enqueued into the shared event queue.
207#
208sub Socket () {
209 # Create the Server socket by calling the responsible function.
210 my $server = &Guardian::Socket::Server();
211
212 # Accept incomming connections from the socket.
213 while (my $connection = $server->accept()) {
214 # Autoflush the socket after the data
215 # has been recieved.
216 $connection->autoflush(1);
217
218 # Gather all data from the connection.
219 while (my $message = <$connection>) {
220 # Remove any newlines.
221 chomp($message);
222
223 # Send the recieved data message to the
224 # socket parser.
225 my $action = &Guardian::Socket::Message_Parser($message);
226
227 # If the parser returns to perform an action,
228 # add it to the main event queue.
229 if ($action) {
230 # Lock the queue.
231 lock($queue);
232
233 # Enqueue the returned action.
234 $queue->enqueue($action);
235 }
236 }
237 }
238}
239
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240#
241## Function for fileposition initialization.
242#
243## This function is used to get the cursor position of the end of file (EOF) of
244## a specified file.
245#
246## In order to prevent from permanently read and keep files opened, or dealing
247## with huge logfiles, at initialization time of the worker processes, the file will
248## be opened once and the cursor position of the end of file (EOF) get stored.
249#
250sub Init_fileposition ($) {
251 my $file = $_[0];
252
253 # Open the file.
254 open(FILE, $file) or die "Could not open $file. $!\n";
255
256 # Just seek to the end of the file (EOF).
257 seek(FILE, 0, 2);
258
259 # Get and store the position.
260 my $position = tell(FILE),
261
262 # Close the file again.
263 close(FILE);
264
265 # Return the position.
266 return $position;
267}
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268
269#
270## Function for capturing process signals.
271#
272## This function captures any sent process signals and will call various
273## actions, basend on the captured signal.
274#
275sub SignalHandler {
276 $SIG{INT} = \&Shutdown;
277 $SIG{TERM} = \&Shutdown;
278 $SIG{QUIT} = \&Shutdown;
279}
280
281#
282## Shutdown function.
283#
284## This function is used to do a clean shutdown of guardian. It will be called
285## by the signal handler when recieving INT (2), QUIT (3) and TERM (15) signals.
286#
287sub Shutdown () {
288 # Remove socket file on exit.
289 &Guardian::Socket::RemoveSocketFile();
290
291 # Exit guardian.
292 exit;
293}