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::Daemon;
  33 require Guardian::Events;
  34 require Guardian::Logger;
  35 require Guardian::Parser;
  36 require Guardian::Socket;
  37
  38 use warnings;
  39
  40 # Disable warnings of unjoinded threads when stopping guardian.
  41 no warnings 'threads';
  42
  43 # Define version.
  44 my $version ="2.0";
  45
  46 # Get and store the given command line arguments in a hash.
  47 my %cmdargs = ();
  48
  49 &GetOptions (\%cmdargs,
  50         'foreground|f',
  51         'config|c=s',
  52         'help|h',
  53         'version|v',
  54 );
  55
  56 # Show help / version information.
  57 if (defined($cmdargs{"help"})) {
  58         print "Guardian $version \n";
  59         print "Usage: guardian <optional arguments>\n";
  60         print " -c, --config\t\tspecifiy a configuration file other than the default (/etc/guardian/guardian.conf)\n";
  61         print " -f, --foreground\trun in the foreground (doesn't fork, any output goes to STDOUT)\n";
  62         print " -h, --help\t\tshows this help\n";
  63         print " -v, --version\t\tdisplay programm version and exit.\n";
  64         exit;
  65 } elsif (defined($cmdargs{"version"})) {
  66         print "Guardian $version \n";
  67         exit;
  68 }
  69
  70 # Check if another instance of guardian is allready running.
  71 if (&Guardian::Daemon::IsRunning()) {
  72         die "Another instance of Guardian is allready running...\n";
  73 }
  74
  75 # Read-in the configuration file and store the settings.
  76 # Push the may be given config file argument.
  77 my %mainsettings = &Guardian::Config::UseConfig($cmdargs{"config"});
  78
  79 # Initialize Logger.
  80 my $logger = Guardian::Logger->Init(%mainsettings);
  81 $logger->Log("debug", "Logger successfully initialized...");
  82
  83 # Add the logger object to the mainsettings for passing
  84 # it to the modules.
  85 $mainsettings{Logger} = $logger;
  86
  87 # Redirect perls "die" messages to the logger before exiting.
  88 $SIG{__DIE__} = sub { $logger->Log("err", "@_"); };
  89
  90 # Initialize the event handler.
  91 my $events = Guardian::Events->Init(%mainsettings);
  92
  93 # Shared hash between the main process and all threads. It will store all
  94 # monitored files and their current file position.
  95 my %monitored_files :shared = ();
  96
  97 # Create the main queue. It is used to store and process all events which are
  98 # reported and enqueued by the worker threads.
  99 my $queue :shared = new Thread::Queue or die "Could not create new, empty queue. $!";;
 100
 101 # Array to store all currently running worker objects.
 102 # (Does not include the socket thread)
 103 my @running_workers;
 104
 105 # Check if guardian should be daemonized or keep in the foreground.
 106 unless (defined($cmdargs{"foreground"})) {
 107         # Fork into background.
 108         &Guardian::Daemon::Daemonize();
 109 } else {
 110         # Write PID (process-id).
 111         &Guardian::Daemon::WritePID();
 112 }
 113
 114 # Call Init function to initzialize guardian.
 115 &Init();
 116
 117 # Infinite main loop, which processes all queued events.
 118 while(1) {
 119         # Get the amount of elements in our queue.
 120         # "undef" will be returned if it is empty.
 121         my $current_events = $queue->pending();
 122
 123         # If there is at least one element enqued
 124         if($current_events > 0) {
 125                 # Grab the data of the top enqueued event.
 126                 my $event = $queue->peek();
 127
 128                 # Log processed event.
 129                 $logger->Log("debug", "QUEUE - Processed event: $event");
 130
 131                 # Send event data to the events parser to determine
 132                 # if any action is required.
 133                 $events->CheckAction($event);
 134
 135                 # Drop processed event from queue.
 136                 $queue->dequeue();
 137         }
 138
 139         # Call RemoveBlocks routine from the Events module to check
 140         # if items from the block list can be dropped.
 141         $events->RemoveBlocks();
 142
 143         # Sleep 10ms to reduce the load of the main process.
 144         sleep(0.01);
 145 }
 146
 147 #
 148 ## Init function.
 149 #
 150 ## This function contains code which has to be executed while guardian
 151 ## is starting.
 152 #
 153 sub Init () {
 154         # Setup signal handler.
 155         &SignalHandler();
 156
 157         # Setup IPC mechanism via Socket in an own thread.
 158         threads->create(\&Socket);
 159
 160         # Generate hash of monitored files.
 161         %monitored_files = &Guardian::Base::GenerateMonitoredFiles(\%mainsettings, \%monitored_files);
 162
 163         # Start worker threads.
 164         &StartWorkers();
 165 }
 166
 167 #
 168 ## Worker function.
 169 #
 170 ## This function is responsible for monitoring modifications of the given logfile,
 171 ## read them and pass them to the message parser.
 172 #
 173 ## To get file modifications the inotify subsystem of the linux kernel is used.
 174 #
 175 ## In order to prevent from permanently read and keep files opened, or dealing
 176 ## with huge logfiles, at initialization time of the worker process, the file will
 177 ## be opened once and the cursor position of the end of file (EOF) get stored. When
 178 ## reading any newly added lines from the file, we directly can jump to the last
 179 ## known position and get these lines. Afterwards, we store the current curser position
 180 ## again, so we can do it in this way over and over again.
 181 #
 182 ## All read lines get stored in an array, which will be passed to the Parser.
 183 #
 184 ## If any response (action) from the parser get recieved, it will be put into the
 185 ## shared event queue.
 186 #
 187 sub Worker ($) {
 188         my $file = $_[0];
 189
 190         # Signal handler to kill worker.
 191         $SIG{'KILL'} = sub { threads->exit(); };
 192
 193         # Create inotify watcher.
 194         my $watcher = new Linux::Inotify2 or die "Could not use inotify. $!";
 195
 196         # Monitor the specified file.
 197         $watcher->watch("$file", IN_MODIFY) or die "Could not monitor $file. $!";
 198
 199         # Switch watcher into non-blocking mode.
 200         $watcher->blocking(0);
 201
 202         # Log successfully spawned worker.
 203         $logger->Log("debug", "Spawned worker thread for: $file");
 204
 205         # Infinite loop.
 206         while(1) {
 207                 # Check for any events and perform them, if there
 208                 # is a least one.
 209                 if ($watcher->read) {
 210                         my @message = ();
 211
 212                         # Obtain fileposition from hash.
 213                         my $fileposition = $monitored_files{$file};
 214
 215                         # Open the file.
 216                         open (FILE, $file) or die "Could not open $file. $!";
 217
 218                         # Seek to the last known position.
 219                         seek (FILE, $fileposition, 0);
 220
 221                         # Get the log message.
 222                         while (my $line = <FILE>) {
 223                                 # Remove any newlines.
 224                                 chomp $line;
 225
 226                                 # Add all lines to the message array.
 227                                 push (@message, $line);
 228                         }
 229
 230                         {
 231                                 # Lock shared hash.
 232                                 lock(%monitored_files);
 233
 234                                 # Update fileposition.
 235                                 $monitored_files{$file} = tell(FILE);
 236                         }
 237
 238                         # Close file.
 239                         close(FILE);
 240
 241                         # Send filename and message to the parser,
 242                         # which will return if an action has to be performed.
 243                         my @action = &Guardian::Parser::Parser("$file", @message);
 244
 245                         # Send the action to the main process and put it into
 246                         # the queue.
 247                         if (@action) {
 248                                 # Lock the queue.
 249                                 lock($queue);
 250
 251                                 # Put the required action into the queue.
 252                                 $queue->enqueue(@action);
 253                         }
 254                 } else {
 255                         # Sleep for 10ms until the next round of the loop will start.
 256                         sleep(0.01);
 257                 }
 258         }
 259 }
 260
 261 #
 262 ## Socket function.
 263 #
 264 ## This function uses the Socket module to create and listen to an UNIX socket.
 265 ## It automatically accepts all incomming connections and pass the recieved
 266 ## data messages to the the Message_Parser function which is also part of the
 267 ## socket module.
 268 #
 269 ## If a valid command has been sent through the socket, the corresponding event
 270 ## will be enqueued into the shared event queue.
 271 #
 272 sub Socket () {
 273         # Create the Server socket by calling the responsible function.
 274         my $server = &Guardian::Socket::Server();
 275
 276         # Log successfull creation of socket.
 277         $logger->Log("debug", "Listening to Socket...");
 278
 279         # Accept incomming connections from the socket.
 280         while (my $connection = $server->accept()) {
 281                 # Autoflush the socket after the data
 282                 # has been recieved.
 283                 $connection->autoflush(1);
 284
 285                 # Gather all data from the connection.
 286                 while (my $message = <$connection>) {
 287                         # Remove any newlines.
 288                         chomp($message);
 289
 290                         # Log recieved socket command.
 291                         $logger->Log("debug", "Socket - Recieved message: $message");
 292
 293                         # Send the recieved data message to the
 294                         # socket parser.
 295                         my $action = &Guardian::Socket::Message_Parser($message);
 296
 297                         # If the parser returns to perform an action,
 298                         # add it to the main event queue.
 299                         if ($action) {
 300                                 # Lock the queue.
 301                                 lock($queue);
 302
 303                                 # Enqueue the returned action.
 304                                 $queue->enqueue($action);
 305                         }
 306                 }
 307         }
 308 }
 309
 310 #
 311 ## Function for capturing process signals.
 312 #
 313 ## This function captures any sent process signals and will call various
 314 ## actions, basend on the captured signal.
 315 #
 316 sub SignalHandler {
 317         $SIG{INT} = \&Shutdown;
 318         $SIG{TERM} = \&Shutdown;
 319         $SIG{QUIT} = \&Shutdown;
 320         $SIG{HUP} = \&Reload;
 321 }
 322
 323 #
 324 ## Function to start the workers (threads) for all monitored files.
 325 #
 326 ## This function will loop through the hash of monitored files and will
 327 ## spawn an own thread based worker for each file. Every created worker will
 328 ## be added to the array of running workers.
 329 #
 330 sub StartWorkers () {
 331         # Loop through the hash which contains the monitored files and start
 332         # a worker thread for each single one.
 333         foreach my $file (keys %monitored_files) {
 334                 $logger->Log("debug", "Starting worker thread for $file");
 335                 # Create worker thread for the file.
 336                 push @running_workers, threads->create(\&Worker,$file);
 337         }
 338 }
 339
 340 #
 341 ## Function to stop all running workers.
 342 #
 343 ## This function is used to stop all currently running workers and will be
 344 ## called when reloading or shutting down guardian.
 345 #
 346 sub StopWorkers () {
 347         # Loop through all running workers.
 348         foreach my $worker (@running_workers) {
 349                 # Send the worker the "KILL" signal and detach the
 350                 # thread so perl can do an automatically clean-up.
 351                 $worker->kill('KILL');
 352         }
 353         $logger->Log("debug", "All workers are stopped now...");
 354 }
 355
 356 #
 357 ## Reload function.
 358 #
 359 ## This function will get called if the signal handler recieves a "SIGHUP" signal,
 360 ## or the reload command will be sent via socket connection. It is responsible for
 361 ## reloading all configure options and stopping/starting the worker threads.
 362 #
 363 sub Reload () {
 364         # Log reload.
 365         $logger->Log("info", "Reload configuration...");
 366
 367         # Stop all running workers.
 368         &StopWorkers();
 369
 370         # Re-read configuration file.
 371         %mainsettings = &Guardian::Config::UseConfig($cmdargs{"config"});
 372
 373         # Update Logger settings.
 374         $logger = Guardian::Logger->Init(%mainsettings);
 375
 376         # Update logger object in mainsettings hash.
 377         $mainsettings{Logger} = $logger;
 378
 379         # Re-generate hash of monitored files.
 380         %monitored_files = &Guardian::Base::GenerateMonitoredFiles(\%mainsettings, \%monitored_files);
 381
 382         # Restart the worker threads.
 383         &StartWorkers();
 384 }
 385
 386 #
 387 ## Shutdown function.
 388 #
 389 ## This function is used to do a clean shutdown of guardian. It will be called
 390 ## by the signal handler when recieving INT (2), QUIT (3) and TERM (15) signals.
 391 #
 392 sub Shutdown () {
 393         # Log shutdown.
 394         $logger->Log("info", "Shutting down...");
 395
 396         # Stop all workers.
 397         &StopWorkers();
 398
 399         # Remove socket file on exit.
 400         &Guardian::Socket::RemoveSocketFile();
 401
 402         # Remove pid file on exit.
 403         &Guardian::Daemon::RemovePIDFile();
 404
 405         # Sleep for one second to give perl some
 406         # time to proper clean up everything before
 407         # exiting.
 408         sleep(1);
 409
 410         # Log good bye message.
 411         $logger->Log("debug", "Good Bye!");
 412
 413         # Exit guardian.
 414         exit;
 415 }