Adjust error messages in case of failure.
[people/stevee/guardian.git] / guardian
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
22 use strict;
23 use threads;
24 use threads::shared;
25 use Getopt::Long;
26 use Thread::Queue;
27 use Linux::Inotify2;
28 use Time::HiRes qw[ time sleep ];
29
30 require Guardian::Base;
31 require Guardian::Config;
32 require Guardian::Logger;
33 require Guardian::Parser;
34 require Guardian::Socket;
35
36 use warnings;
37
38 # Disable warnings of unjoinded threads when stopping guardian.
39 no warnings 'threads';
40
41 # Define version.
42 my $version ="2.0";
43
44 # Get and store the given command line arguments in a hash.
45 my %cmdargs = ();
46
47 &GetOptions (\%cmdargs,
48 'foreground|f',
49 'config|c=s',
50 'help|h',
51 'version|v',
52 );
53
54 # Show help / version information.
55 if (defined($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 $version \n";
65 exit;
66 }
67
68 # Read-in the configuration file and store the settings.
69 # Push the may be given config file argument.
70 my %mainsettings = &Guardian::Config::UseConfig($cmdargs{"config"});
71
72 # Initialize Logger.
73 my $logger = Guardian::Logger->New(%mainsettings);
74 $logger->Log("debug", "Logger successfully initialized...");
75
76 # Redirect perls "die" messages to the logger before exiting.
77 $SIG{__DIE__} = sub { $logger->Log("err", "@_"); };
78
79 # Shared hash between the main process and all threads. It will store all
80 # monitored files and their current file position.
81 my %monitored_files :shared = ();
82
83 # Create the main queue. It is used to store and process all events which are
84 # reported and enqueued by the worker threads.
85 my $queue :shared = new Thread::Queue or die "Could not create new, empty queue. $!";;
86
87 # Array to store all currently running worker objects.
88 # (Does not include the socket thread)
89 my @running_workers;
90
91 # Call Init function to initzialize guardian.
92 &Init();
93
94 # Infinite main loop, which processes all queued events.
95 while(1) {
96 # Get the amount of elements in our queue.
97 # "undef" will be returned if it is empty.
98 my $current_events = $queue->pending();
99
100 # If there is at least one element enqued
101 if($current_events > 0) {
102 # Grab the data of the top enqueued event.
103 my $event = $queue->peek();
104
105 # Log processed event.
106 $logger->Log("debug", "QUEUE - Processed event: $event");
107
108 # Drop processed event from queue.
109 $queue->dequeue();
110 }
111
112 # Sleep 10ms to reduce the load of the main process.
113 sleep(0.01);
114 }
115
116 #
117 ## Init function.
118 #
119 ## This function contains code which has to be executed while guardian
120 ## is starting.
121 #
122 sub Init () {
123 # Setup signal handler.
124 &SignalHandler();
125
126 # Setup IPC mechanism via Socket in an own thread.
127 threads->create(\&Socket);
128
129 # Generate hash of monitored files.
130 %monitored_files = &Guardian::Base::GenerateMonitoredFiles(\%mainsettings, \%monitored_files);
131
132 # Start worker threads.
133 &StartWorkers();
134 }
135
136 #
137 ## Worker function.
138 #
139 ## This function is responsible for monitoring modifications of the given logfile,
140 ## read them and pass them to the message parser.
141 #
142 ## To get file modifications the inotify subsystem of the linux kernel is used.
143 #
144 ## In order to prevent from permanently read and keep files opened, or dealing
145 ## with huge logfiles, at initialization time of the worker process, the file will
146 ## be opened once and the cursor position of the end of file (EOF) get stored. When
147 ## reading any newly added lines from the file, we directly can jump to the last
148 ## known position and get these lines. Afterwards, we store the current curser position
149 ## again, so we can do it in this way over and over again.
150 #
151 ## All read lines get stored in an array, which will be passed to the Parser.
152 #
153 ## If any response (action) from the parser get recieved, it will be put into the
154 ## shared event queue.
155 #
156 sub Worker ($) {
157 my $file = $_[0];
158
159 # Signal handler to kill worker.
160 $SIG{'KILL'} = sub { threads->exit(); };
161
162 # Create inotify watcher.
163 my $watcher = new Linux::Inotify2 or die "Could not use inotify. $!";
164
165 # Monitor the specified file.
166 $watcher->watch("$file", IN_MODIFY) or die "Could not monitor $file. $!";
167
168 # Switch watcher into non-blocking mode.
169 $watcher->blocking(0);
170
171 # Log successfully spawned worker.
172 $logger->Log("debug", "Spawned worker thread for: $file");
173
174 # Infinite loop.
175 while(1) {
176 # Check for any events and perform them, if there
177 # is a least one.
178 if ($watcher->read) {
179 my @message = ();
180
181 # Obtain fileposition from hash.
182 my $fileposition = $monitored_files{$file};
183
184 # Open the file.
185 open (FILE, $file) or die "Could not open $file. $!";
186
187 # Seek to the last known position.
188 seek (FILE, $fileposition, 0);
189
190 # Get the log message.
191 while (my $line = <FILE>) {
192 # Remove any newlines.
193 chomp $line;
194
195 # Add all lines to the message array.
196 push (@message, $line);
197 }
198
199 {
200 # Lock shared hash.
201 lock(%monitored_files);
202
203 # Update fileposition.
204 $monitored_files{$file} = tell(FILE);
205 }
206
207 # Close file.
208 close(FILE);
209
210 # Send filename and message to the parser,
211 # which will return if an action has to be performed.
212 my @action = &Guardian::Parser::Parser("$file", @message);
213
214 # Send the action to the main process and put it into
215 # the queue.
216 if (@action) {
217 # Lock the queue.
218 lock($queue);
219
220 # Put the required action into the queue.
221 $queue->enqueue(@action);
222 }
223 } else {
224 # Sleep for 10ms until the next round of the loop will start.
225 sleep(0.01);
226 }
227 }
228 }
229
230 #
231 ## Socket function.
232 #
233 ## This function uses the Socket module to create and listen to an UNIX socket.
234 ## It automatically accepts all incomming connections and pass the recieved
235 ## data messages to the the Message_Parser function which is also part of the
236 ## socket module.
237 #
238 ## If a valid command has been sent through the socket, the corresponding event
239 ## will be enqueued into the shared event queue.
240 #
241 sub Socket () {
242 # Create the Server socket by calling the responsible function.
243 my $server = &Guardian::Socket::Server();
244
245 # Log successfull creation of socket.
246 $logger->Log("debug", "Listening to Socket...");
247
248 # Accept incomming connections from the socket.
249 while (my $connection = $server->accept()) {
250 # Autoflush the socket after the data
251 # has been recieved.
252 $connection->autoflush(1);
253
254 # Gather all data from the connection.
255 while (my $message = <$connection>) {
256 # Remove any newlines.
257 chomp($message);
258
259 # Log recieved socket command.
260 $logger->Log("debug", "Socket - Recieved message: $message");
261
262 # Send the recieved data message to the
263 # socket parser.
264 my $action = &Guardian::Socket::Message_Parser($message);
265
266 # If the parser returns to perform an action,
267 # add it to the main event queue.
268 if ($action) {
269 # Lock the queue.
270 lock($queue);
271
272 # Enqueue the returned action.
273 $queue->enqueue($action);
274 }
275 }
276 }
277 }
278
279 #
280 ## Function for capturing process signals.
281 #
282 ## This function captures any sent process signals and will call various
283 ## actions, basend on the captured signal.
284 #
285 sub SignalHandler {
286 $SIG{INT} = \&Shutdown;
287 $SIG{TERM} = \&Shutdown;
288 $SIG{QUIT} = \&Shutdown;
289 $SIG{HUP} = \&Reload;
290 }
291
292 #
293 ## Function to start the workers (threads) for all monitored files.
294 #
295 ## This function will loop through the hash of monitored files and will
296 ## spawn an own thread based worker for each file. Every created worker will
297 ## be added to the array of running workers.
298 #
299 sub StartWorkers () {
300 # Loop through the hash which contains the monitored files and start
301 # a worker thread for each single one.
302 foreach my $file (keys %monitored_files) {
303 $logger->Log("debug", "Starting worker thread for $file");
304 # Create worker thread for the file.
305 push @running_workers, threads->create(\&Worker,$file);
306 }
307 }
308
309 #
310 ## Function to stop all running workers.
311 #
312 ## This function is used to stop all currently running workers and will be
313 ## called when reloading or shutting down guardian.
314 #
315 sub StopWorkers () {
316 # Loop through all running workers.
317 foreach my $worker (@running_workers) {
318 # Send the worker the "KILL" signal and detach the
319 # thread so perl can do an automatically clean-up.
320 $worker->kill('KILL');
321 }
322 $logger->Log("debug", "All workers are stopped now...");
323 }
324
325 #
326 ## Reload function.
327 #
328 ## This function will get called if the signal handler recieves a "SIGHUP" signal,
329 ## or the reload command will be sent via socket connection. It is responsible for
330 ## reloading all configure options and stopping/starting the worker threads.
331 #
332 sub Reload () {
333 # Log reload.
334 $logger->Log("info", "Reload configuration...");
335
336 # Stop all running workers.
337 &StopWorkers();
338
339 # Re-read configuration file.
340 %mainsettings = &Guardian::Config::UseConfig($cmdargs{"config"});
341
342 # Re-generate hash of monitored files.
343 %monitored_files = &Guardian::Base::GenerateMonitoredFiles(\%mainsettings, \%monitored_files);
344
345 # Restart the worker threads.
346 &StartWorkers();
347 }
348
349 #
350 ## Shutdown function.
351 #
352 ## This function is used to do a clean shutdown of guardian. It will be called
353 ## by the signal handler when recieving INT (2), QUIT (3) and TERM (15) signals.
354 #
355 sub Shutdown () {
356 # Log shutdown.
357 $logger->Log("info", "Shutting down...");
358
359 # Stop all workers.
360 &StopWorkers();
361
362 # Remove socket file on exit.
363 &Guardian::Socket::RemoveSocketFile();
364
365 # Sleep for one second to give perl some
366 # time to proper clean up everything before
367 # exiting.
368 sleep(1);
369
370 # Log good bye message.
371 $logger->Log("debug", "Good Bye!");
372
373 # Exit guardian.
374 exit;
375 }