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git.ipfire.org Git - people/stevee/guardian.git/blob - guardian
af5caebf152c89b473a0b42fc476fc53b951a63e
2 ###############################################################################
4 # IPFire.org - A linux based firewall #
5 # Copyright (C) 2015 IPFire Development Team #
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. #
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. #
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/>. #
20 ###############################################################################
28 use Time
::HiRes qw
[ time sleep ];
30 require Guardian
::Config
;
31 require Guardian
::Parser
;
32 require Guardian
::Socket
;
37 # Array to store the monitored logfiles.
38 my @monitored_files = (
39 "/var/log/snort/alert",
42 # Get and store the given command line arguments in a hash.
45 &GetOptions
(\
%cmdargs,
52 # Show help / version information.
53 if (defined($cmdargs{"help"})) {
54 print "Guardian $version \n";
55 print "Usage: guardian <optional arguments>\n";
56 print " -c, --config\t\tspecifiy a configuration file other than the default (/etc/guardian/guardian.conf)\n";
57 print " -f, --foreground\trun in the foreground (doesn't fork, any output goes to STDOUT)\n";
58 print " -h, --help\t\tshows this help\n";
59 print " -v, --version\t\tdisplay programm version and exit.\n";
61 } elsif (defined($cmdargs{"version"})) {
62 print "Guardian $version \n";
66 # Read-in the configuration file and store the settings.
67 # Push the may be given config file argument.
68 my %mainsettings = &Guardian
::Config
::UseConfig
($cmdargs{"config"});
70 # Create the main queue. It is used to store and process all events which are
71 # reported and enqueued by the worker threads.
72 my $queue :shared
= new Thread
::Queue
or die "Could not create new, empty queue. $!\n";;
74 # Call Init function to initzialize guardian.
77 # Infinite main loop, which processes all queued events.
79 # Get the amount of elements in our queue.
80 # "undef" will be returned if it is empty.
81 my $current_events = $queue->pending();
83 # If there is at least one element enqued
84 if($current_events > 0) {
85 # Grab the data of the top enqueued event.
86 my $event = $queue->peek();
88 print "Got event: $event\n";
90 # Drop processed event from queue.
94 # Sleep 10ms to reduce the load of the main process.
101 ## This function contains code which has to be executed while guardian
105 # Setup signal handler.
108 # Setup IPC mechanism via Socket in an own thread.
109 threads
->create(\
&Socket
);
111 # Loop through the array of which files should be monitored and
112 # create a worker thread for each single one.
113 foreach my $monitored_file (@monitored_files) {
114 # Check if the file exists and is readable.
115 if (-r
"$monitored_file") {
116 # Create worker thread for the file.
117 threads
->create(\
&Worker
,$monitored_file);
125 ## This function is responsible for monitoring modifications of the given logfile,
126 ## read them and pass them to the message parser.
128 ## To get file modifications the inotify subsystem of the linux kernel is used.
130 ## In order to prevent from permanently read and keep files opened, or dealing
131 ## with huge logfiles, at initialization time of the worker process, the file will
132 ## be opened once and the cursor position of the end of file (EOF) get stored. When
133 ## reading any newly added lines from the file, we directly can jump to the last
134 ## known position and get these lines. Afterwards, we store the current curser position
135 ## again, so we can do it in this way over and over again.
137 ## All read lines get stored in an array, which will be passed to the Parser.
139 ## If any response (action) from the parser get recieved, it will be put into the
140 ## shared event queue.
145 # Get the fileposition.
146 my $fileposition = &Init_fileposition
("$file");
148 # Create inotify watcher.
149 my $watcher = new Linux
::Inotify2
or die "Could not use inotify. $!\n";
151 # Monitor the specified file.
152 $watcher->watch("$file", IN_MODIFY
) or die "Could not monitor $file. $!\n";
154 # Get all notifications.
155 while ($watcher->read) {
159 open (FILE
, $file) or die "Could not open $file. $!\n";
161 # Seek to the last known position.
162 seek (FILE
, $fileposition, 0);
164 # Get the log message.
165 while (my $line = <FILE
>) {
166 # Remove any newlines.
169 # Add all lines to the message array.
170 push (@message, $line);
173 # Update fileposition.
174 $fileposition = tell(FILE
);
179 # Send filename and message to the parser,
180 # which will return if an action has to be performed.
181 my @action = &Guardian
::Parser
::Parser
("$file", @message);
183 # Send the action to the main process and put it into
189 # Put the required action into the queue.
190 $queue->enqueue(@action);
198 ## This function uses the Socket module to create and listen to an UNIX socket.
199 ## It automatically accepts all incomming connections and pass the recieved
200 ## data messages to the the Message_Parser function which is also part of the
203 ## If a valid command has been sent through the socket, the corresponding event
204 ## will be enqueued into the shared event queue.
207 # Create the Server socket by calling the responsible function.
208 my $server = &Guardian
::Socket
::Server
();
210 # Accept incomming connections from the socket.
211 while (my $connection = $server->accept()) {
212 # Autoflush the socket after the data
214 $connection->autoflush(1);
216 # Gather all data from the connection.
217 while (my $message = <$connection>) {
218 # Remove any newlines.
221 # Send the recieved data message to the
223 my $action = &Guardian
::Socket
::Message_Parser
($message);
225 # If the parser returns to perform an action,
226 # add it to the main event queue.
231 # Enqueue the returned action.
232 $queue->enqueue($action);
239 ## Function for fileposition initialization.
241 ## This function is used to get the cursor position of the end of file (EOF) of
244 ## In order to prevent from permanently read and keep files opened, or dealing
245 ## with huge logfiles, at initialization time of the worker processes, the file will
246 ## be opened once and the cursor position of the end of file (EOF) get stored.
248 sub Init_fileposition
($) {
252 open(FILE
, $file) or die "Could not open $file. $!\n";
254 # Just seek to the end of the file (EOF).
257 # Get and store the position.
258 my $position = tell(FILE
),
260 # Close the file again.
263 # Return the position.
268 ## Function for capturing process signals.
270 ## This function captures any sent process signals and will call various
271 ## actions, basend on the captured signal.
274 $SIG{INT
} = \
&Shutdown
;
275 $SIG{TERM
} = \
&Shutdown
;
276 $SIG{QUIT
} = \
&Shutdown
;
280 ## Shutdown function.
282 ## This function is used to do a clean shutdown of guardian. It will be called
283 ## by the signal handler when recieving INT (2), QUIT (3) and TERM (15) signals.
286 # Remove socket file on exit.
287 &Guardian
::Socket
::RemoveSocketFile
();