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