Add support to reload the service.
[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
3111df62 30require Guardian::Base;
45bf2a03 31require Guardian::Config;
88d9af2c 32require Guardian::Parser;
6abac3d4 33require Guardian::Socket;
88d9af2c 34
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35use warnings;
36
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37# Define version.
38my $version ="2.0";
39
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40# Get and store the given command line arguments in a hash.
41my %cmdargs = ();
42
43&GetOptions (\%cmdargs,
44 'foreground|f',
45 'config|c=s',
46 'help|h',
47 'version|v',
48);
49
50# Show help / version information.
51if (defined($cmdargs{"help"})) {
52 print "Guardian $version \n";
53 print "Usage: guardian <optional arguments>\n";
54 print " -c, --config\t\tspecifiy a configuration file other than the default (/etc/guardian/guardian.conf)\n";
55 print " -f, --foreground\trun in the foreground (doesn't fork, any output goes to STDOUT)\n";
56 print " -h, --help\t\tshows this help\n";
57 print " -v, --version\t\tdisplay programm version and exit.\n";
58 exit;
59} elsif (defined($cmdargs{"version"})) {
60 print "Guardian $version \n";
61 exit;
62}
63
64# Read-in the configuration file and store the settings.
65# Push the may be given config file argument.
66my %mainsettings = &Guardian::Config::UseConfig($cmdargs{"config"});
67
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68# Shared hash between the main process and all threads. It will store all
69# monitored files and their current file position.
70my %monitored_files :shared = ();
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
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76# Array to store all currently running worker objects.
77# (Does not include the socket thread)
78my @running_workers;
79
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80# Call Init function to initzialize guardian.
81&Init();
82
83# Infinite main loop, which processes all queued events.
84while(1) {
85 # Get the amount of elements in our queue.
86 # "undef" will be returned if it is empty.
87 my $current_events = $queue->pending();
88
89 # If there is at least one element enqued
90 if($current_events > 0) {
91 # Grab the data of the top enqueued event.
92 my $event = $queue->peek();
93
94 print "Got event: $event\n";
95
96 # Drop processed event from queue.
97 $queue->dequeue();
98 }
99
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100 # Sleep 10ms to reduce the load of the main process.
101 sleep(0.01);
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102}
103
104#
105## Init function.
106#
107## This function contains code which has to be executed while guardian
108## is starting.
109#
110sub Init () {
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111 # Setup signal handler.
112 &SignalHandler();
113
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114 # Setup IPC mechanism via Socket in an own thread.
115 threads->create(\&Socket);
116
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117 # Generate hash of monitored files.
118 %monitored_files = &Guardian::Base::GenerateMonitoredFiles(\%mainsettings, \%monitored_files);
119
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120 # Start worker threads.
121 &StartWorkers();
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122}
123
124#
125## Worker function.
126#
127## This function is responsible for monitoring modifications of the given logfile,
128## read them and pass them to the message parser.
129#
130## To get file modifications the inotify subsystem of the linux kernel is used.
131#
132## In order to prevent from permanently read and keep files opened, or dealing
133## with huge logfiles, at initialization time of the worker process, the file will
134## be opened once and the cursor position of the end of file (EOF) get stored. When
135## reading any newly added lines from the file, we directly can jump to the last
136## known position and get these lines. Afterwards, we store the current curser position
137## again, so we can do it in this way over and over again.
138#
139## All read lines get stored in an array, which will be passed to the Parser.
140#
141## If any response (action) from the parser get recieved, it will be put into the
142## shared event queue.
143#
144sub Worker ($) {
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145 my $file = $_[0];
146
147 # Signal handler to kill worker.
148 $SIG{'KILL'} = sub { threads->exit(); };
88d9af2c 149
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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
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156 # Switch watcher into non-blocking mode.
157 $watcher->blocking(0);
88d9af2c 158
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159 # Infinite loop.
160 while(1) {
161 # Check for any events and perform them, if there
162 # is a least one.
163 if ($watcher->read) {
164 my @message = ();
88d9af2c 165
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166 # Obtain fileposition from hash.
167 my $fileposition = $monitored_files{$file};
168
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169 # Open the file.
170 open (FILE, $file) or die "Could not open $file. $!\n";
88d9af2c 171
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172 # Seek to the last known position.
173 seek (FILE, $fileposition, 0);
88d9af2c 174
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175 # Get the log message.
176 while (my $line = <FILE>) {
177 # Remove any newlines.
178 chomp $line;
88d9af2c 179
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180 # Add all lines to the message array.
181 push (@message, $line);
182 }
88d9af2c 183
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184 {
185 # Lock shared hash.
186 lock(%monitored_files);
187
188 # Update fileposition.
189 $monitored_files{$file} = tell(FILE);
190 }
88d9af2c 191
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192 # Close file.
193 close(FILE);
88d9af2c 194
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195 # Send filename and message to the parser,
196 # which will return if an action has to be performed.
197 my @action = &Guardian::Parser::Parser("$file", @message);
88d9af2c 198
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199 # Send the action to the main process and put it into
200 # the queue.
201 if (@action) {
202 # Lock the queue.
203 lock($queue);
204
205 # Put the required action into the queue.
206 $queue->enqueue(@action);
207 }
208 } else {
209 # Sleep for 10ms until the next round of the loop will start.
210 sleep(0.01);
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211 }
212 }
213}
214
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215#
216## Socket function.
217#
218## This function uses the Socket module to create and listen to an UNIX socket.
219## It automatically accepts all incomming connections and pass the recieved
220## data messages to the the Message_Parser function which is also part of the
221## socket module.
222#
223## If a valid command has been sent through the socket, the corresponding event
224## will be enqueued into the shared event queue.
225#
226sub Socket () {
227 # Create the Server socket by calling the responsible function.
228 my $server = &Guardian::Socket::Server();
229
230 # Accept incomming connections from the socket.
231 while (my $connection = $server->accept()) {
232 # Autoflush the socket after the data
233 # has been recieved.
234 $connection->autoflush(1);
235
236 # Gather all data from the connection.
237 while (my $message = <$connection>) {
238 # Remove any newlines.
239 chomp($message);
240
241 # Send the recieved data message to the
242 # socket parser.
243 my $action = &Guardian::Socket::Message_Parser($message);
244
245 # If the parser returns to perform an action,
246 # add it to the main event queue.
247 if ($action) {
248 # Lock the queue.
249 lock($queue);
250
251 # Enqueue the returned action.
252 $queue->enqueue($action);
253 }
254 }
255 }
256}
257
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258#
259## Function for capturing process signals.
260#
261## This function captures any sent process signals and will call various
262## actions, basend on the captured signal.
263#
264sub SignalHandler {
265 $SIG{INT} = \&Shutdown;
266 $SIG{TERM} = \&Shutdown;
267 $SIG{QUIT} = \&Shutdown;
ba734c53 268 $SIG{HUP} = \&Reload;
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269}
270
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271#
272## Function to start the workers (threads) for all monitored files.
273#
3111df62 274## This function will loop through the hash of monitored files and will
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275## spawn an own thread based worker for each file. Every created worker will
276## be added to the array of running workers.
277#
278sub StartWorkers () {
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279 # Loop through the hash which contains the monitored files and start
280 # a worker thread for each single one.
281 foreach my $file (keys %monitored_files) {
282 # Create worker thread for the file.
283 push @running_workers, threads->create(\&Worker,$file);
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284 }
285}
286
287#
288## Function to stop all running workers.
289#
290## This function is used to stop all currently running workers and will be
291## called when reloading or shutting down guardian.
292#
293sub StopWorkers () {
294 # Loop through all running workers.
295 foreach my $worker (@running_workers) {
296 # Send the worker the "KILL" signal and detach the
297 # thread so perl can do an automatically clean-up.
298 $worker->kill('KILL')->detach();
299 }
300}
301
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302#
303## Reload function.
304#
305## This function will get called if the signal handler recieves a "SIGHUP" signal,
306## or the reload command will be sent via socket connection. It is responsible for
307## reloading all configure options and stopping/starting the worker threads.
308#
309sub Reload () {
310 # Stop all running workers.
311 &StopWorkers();
312
313 # Re-read configuration file.
314 %mainsettings = &Guardian::Config::UseConfig($cmdargs{"config"});
315
316 # Re-generate hash of monitored files.
317 %monitored_files = &Guardian::Base::GenerateMonitoredFiles(\%mainsettings, \%monitored_files);
318
319 # Restart the worker threads.
320 &StartWorkers();
321}
322
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323#
324## Shutdown function.
325#
326## This function is used to do a clean shutdown of guardian. It will be called
327## by the signal handler when recieving INT (2), QUIT (3) and TERM (15) signals.
328#
329sub Shutdown () {
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330 # Stop all workers.
331 &StopWorkers();
332
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333 # Remove socket file on exit.
334 &Guardian::Socket::RemoveSocketFile();
335
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336 # Sleep for one second to give perl some
337 # time to proper clean up everything before
338 # exiting.
339 sleep(1);
340
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341 # Exit guardian.
342 exit;
343}