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 # Hash to store the currently monitored files and their configured
  94 # parsers.
  95 my %monitored_files = ();
  96
  97 # Shared hash between the main process and all threads. It will store the
  98 # monitored files and their current file position.
  99 my %file_positions :shared = ();
 100
 101 # Create the main queue. It is used to store and process all events which are
 102 # reported and enqueued by the worker threads.
 103 my $queue :shared = new Thread::Queue or die "Could not create new, empty queue. $!";;
 104
 105 # Array to store all currently running worker objects.
 106 # (Does not include the socket thread)
 107 my @running_workers;
 108
 109 # Check if guardian should be daemonized or keep in the foreground.
 110 unless (defined($cmdargs{"foreground"})) {
 111         # Fork into background.
 112         &Guardian::Daemon::Daemonize();
 113 } else {
 114         # Write PID (process-id).
 115         &Guardian::Daemon::WritePID();
 116 }
 117
 118 # Call Init function to initzialize guardian.
 119 &Init();
 120
 121 # Infinite main loop, which processes all queued events.
 122 while(1) {
 123         # Get the amount of elements in our queue.
 124         # "undef" will be returned if it is empty.
 125         my $current_events = $queue->pending();
 126
 127         # If there is at least one element enqued
 128         if($current_events > 0) {
 129                 # Grab the data of the top enqueued event.
 130                 my $event = $queue->peek();
 131
 132                 # Log processed event.
 133                 $logger->Log("debug", "QUEUE - Processed event: $event");
 134
 135                 # Send event data to the events parser to determine
 136                 # if any action is required.
 137                 $events->CheckAction($event);
 138
 139                 # Drop processed event from queue.
 140                 $queue->dequeue();
 141         }
 142
 143         # Call RemoveBlocks routine from the Events module to check
 144         # if items from the block list can be dropped.
 145         $events->RemoveBlocks();
 146
 147         # Sleep 10ms to reduce the load of the main process.
 148         sleep(0.01);
 149 }
 150
 151 #
 152 ## Init function.
 153 #
 154 ## This function contains code which has to be executed while guardian
 155 ## is starting.
 156 #
 157 sub Init () {
 158         # Setup signal handler.
 159         &SignalHandler();
 160
 161         # Setup IPC mechanism via Socket in an own thread.
 162         threads->create(\&Socket);
 163
 164         # Generate hash of monitored files.
 165         %monitored_files = &Guardian::Base::GenerateMonitoredFiles(\%mainsettings, \%monitored_files);
 166
 167         # Start worker threads.
 168         &StartWorkers();
 169 }
 170
 171 #
 172 ## Worker function.
 173 #
 174 ## This function is responsible for monitoring modifications of the given logfile,
 175 ## read them and pass them to the message parser.
 176 #
 177 ## To get file modifications the inotify subsystem of the linux kernel is used.
 178 #
 179 ## In order to prevent from permanently read and keep files opened, or dealing
 180 ## with huge logfiles, at initialization time of the worker process, the file will
 181 ## be opened once and the cursor position of the end of file (EOF) get stored. When
 182 ## reading any newly added lines from the file, we directly can jump to the last
 183 ## known position and get these lines. Afterwards, we store the current curser position
 184 ## again, so we can do it in this way over and over again.
 185 #
 186 ## All read lines get stored in an array, which will be passed to the Parser.
 187 #
 188 ## If any response (action) from the parser get recieved, it will be put into the
 189 ## shared event queue.
 190 #
 191 sub Worker ($) {
 192         my $file = $_[0];
 193
 194         # Obtain the parser name which should be used to parser any
 195         # messages of this file.
 196         my $parser = $monitored_files{$file};
 197
 198         # Signal handler to kill worker.
 199         $SIG{'KILL'} = sub { threads->exit(); };
 200
 201         # Create inotify watcher.
 202         my $watcher = new Linux::Inotify2 or die "Could not use inotify. $!";
 203
 204         # Monitor the specified file.
 205         $watcher->watch("$file", IN_MODIFY) or die "Could not monitor $file. $!";
 206
 207         # Switch watcher into non-blocking mode.
 208         $watcher->blocking(0);
 209
 210         # Log successfully spawned worker.
 211         $logger->Log("debug", "Spawned worker thread for: $file");
 212
 213         # Infinite loop.
 214         while(1) {
 215                 # Check for any events and perform them, if there
 216                 # is a least one.
 217                 if ($watcher->read) {
 218                         my @message = ();
 219
 220                         # Obtain fileposition from hash.
 221                         my $fileposition = $file_positions{$file};
 222
 223                         # Open the file.
 224                         open (FILE, $file) or die "Could not open $file. $!";
 225
 226                         # Seek to the last known position.
 227                         seek (FILE, $fileposition, 0);
 228
 229                         # Get the log message.
 230                         while (my $line = <FILE>) {
 231                                 # Remove any newlines.
 232                                 chomp $line;
 233
 234                                 # Add all lines to the message array.
 235                                 push (@message, $line);
 236                         }
 237
 238                         {
 239                                 # Lock shared hash.
 240                                 lock(%file_positions);
 241
 242                                 # Update fileposition.
 243                                 $file_positions{$file} = tell(FILE);
 244                         }
 245
 246                         # Close file.
 247                         close(FILE);
 248
 249                         # Send filename and message to the parser,
 250                         # which will return if an action has to be performed.
 251                         my @action = &Guardian::Parser::Parser("$parser", @message);
 252
 253                         # Send the action to the main process and put it into
 254                         # the queue.
 255                         if (@action) {
 256                                 # Lock the queue.
 257                                 lock($queue);
 258
 259                                 # Put the required action into the queue.
 260                                 $queue->enqueue(@action);
 261                         }
 262                 } else {
 263                         # Sleep for 10ms until the next round of the loop will start.
 264                         sleep(0.01);
 265                 }
 266         }
 267 }
 268
 269 #
 270 ## Socket function.
 271 #
 272 ## This function uses the Socket module to create and listen to an UNIX socket.
 273 ## It automatically accepts all incomming connections and pass the recieved
 274 ## data messages to the the Message_Parser function which is also part of the
 275 ## socket module.
 276 #
 277 ## If a valid command has been sent through the socket, the corresponding event
 278 ## will be enqueued into the shared event queue.
 279 #
 280 sub Socket () {
 281         # Create the Server socket by calling the responsible function.
 282         my $server = &Guardian::Socket::Server();
 283
 284         # Log successfull creation of socket.
 285         $logger->Log("debug", "Listening to Socket...");
 286
 287         # Accept incomming connections from the socket.
 288         while (my $connection = $server->accept()) {
 289                 # Autoflush the socket after the data
 290                 # has been recieved.
 291                 $connection->autoflush(1);
 292
 293                 # Gather all data from the connection.
 294                 while (my $message = <$connection>) {
 295                         # Remove any newlines.
 296                         chomp($message);
 297
 298                         # Log recieved socket command.
 299                         $logger->Log("debug", "Socket - Recieved message: $message");
 300
 301                         # Send the recieved data message to the
 302                         # socket parser.
 303                         my $action = &Guardian::Socket::Message_Parser($message);
 304
 305                         # If the parser returns to perform an action,
 306                         # add it to the main event queue.
 307                         if ($action) {
 308                                 # Lock the queue.
 309                                 lock($queue);
 310
 311                                 # Enqueue the returned action.
 312                                 $queue->enqueue($action);
 313                         }
 314                 }
 315         }
 316 }
 317
 318 #
 319 ## Function for capturing process signals.
 320 #
 321 ## This function captures any sent process signals and will call various
 322 ## actions, basend on the captured signal.
 323 #
 324 sub SignalHandler {
 325         $SIG{INT} = \&Shutdown;
 326         $SIG{TERM} = \&Shutdown;
 327         $SIG{QUIT} = \&Shutdown;
 328         $SIG{HUP} = \&Reload;
 329 }
 330
 331 #
 332 ## Function to start the workers (threads) for all monitored files.
 333 #
 334 ## This function will loop through the hash of monitored files and will
 335 ## spawn an own thread based worker for each file. Every created worker will
 336 ## be added to the array of running workers.
 337 #
 338 sub StartWorkers () {
 339         # Init/Update hash which contains the cursor position of EOF.
 340         %file_positions = &Guardian::Base::FilePositions(\%monitored_files, \%file_positions);
 341
 342         # Loop through the hash which contains the monitored files and start
 343         # a worker thread for each single one.
 344         foreach my $file (keys %monitored_files) {
 345                 $logger->Log("debug", "Starting worker thread for $file");
 346                 # Create worker thread for the file.
 347                 push @running_workers, threads->create(\&Worker,$file);
 348         }
 349 }
 350
 351 #
 352 ## Function to stop all running workers.
 353 #
 354 ## This function is used to stop all currently running workers and will be
 355 ## called when reloading or shutting down guardian.
 356 #
 357 sub StopWorkers () {
 358         # Loop through all running workers.
 359         foreach my $worker (@running_workers) {
 360                 # Send the worker the "KILL" signal and detach the
 361                 # thread so perl can do an automatically clean-up.
 362                 $worker->kill('KILL');
 363         }
 364         $logger->Log("debug", "All workers are stopped now...");
 365 }
 366
 367 #
 368 ## Reload function.
 369 #
 370 ## This function will get called if the signal handler recieves a "SIGHUP" signal,
 371 ## or the reload command will be sent via socket connection. It is responsible for
 372 ## reloading all configure options and stopping/starting the worker threads.
 373 #
 374 sub Reload () {
 375         # Log reload.
 376         $logger->Log("info", "Reload configuration...");
 377
 378         # Stop all running workers.
 379         &StopWorkers();
 380
 381         # Re-read configuration file.
 382         %mainsettings = &Guardian::Config::UseConfig($cmdargs{"config"});
 383
 384         # Update Logger settings.
 385         $logger = Guardian::Logger->Init(%mainsettings);
 386
 387         # Update logger object in mainsettings hash.
 388         $mainsettings{Logger} = $logger;
 389
 390         # Re-generate hash of monitored files.
 391         %monitored_files = &Guardian::Base::GenerateMonitoredFiles(\%mainsettings, \%monitored_files);
 392
 393         # Restart the worker threads.
 394         &StartWorkers();
 395 }
 396
 397 #
 398 ## Shutdown function.
 399 #
 400 ## This function is used to do a clean shutdown of guardian. It will be called
 401 ## by the signal handler when recieving INT (2), QUIT (3) and TERM (15) signals.
 402 #
 403 sub Shutdown () {
 404         # Log shutdown.
 405         $logger->Log("info", "Shutting down...");
 406
 407         # Stop all workers.
 408         &StopWorkers();
 409
 410         # Remove socket file on exit.
 411         &Guardian::Socket::RemoveSocketFile();
 412
 413         # Remove pid file on exit.
 414         &Guardian::Daemon::RemovePIDFile();
 415
 416         # Sleep for one second to give perl some
 417         # time to proper clean up everything before
 418         # exiting.
 419         sleep(1);
 420
 421         # Log good bye message.
 422         $logger->Log("debug", "Good Bye!");
 423
 424         # Exit guardian.
 425         exit;
 426 }