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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 | ||
22 | use strict; | |
23 | use threads; | |
24 | use threads::shared; | |
25 | use Thread::Queue; | |
26 | use Linux::Inotify2; | |
27 | ||
28 | require Guardian::Parser; | |
6abac3d4 | 29 | require Guardian::Socket; |
88d9af2c SS |
30 | |
31 | # Array to store the monitored logfiles. | |
32 | my @monitored_files = ( | |
33 | "/var/log/snort/alert", | |
34 | ); | |
35 | ||
36 | # Create the main queue. It is used to store and process all events which are | |
37 | # reported and enqueued by the worker threads. | |
38 | my $queue :shared = new Thread::Queue or die "Could not create new, empty queue. $!\n";; | |
39 | ||
40 | # Call Init function to initzialize guardian. | |
41 | &Init(); | |
42 | ||
43 | # Infinite main loop, which processes all queued events. | |
44 | while(1) { | |
45 | # Get the amount of elements in our queue. | |
46 | # "undef" will be returned if it is empty. | |
47 | my $current_events = $queue->pending(); | |
48 | ||
49 | # If there is at least one element enqued | |
50 | if($current_events > 0) { | |
51 | # Grab the data of the top enqueued event. | |
52 | my $event = $queue->peek(); | |
53 | ||
54 | print "Got event: $event\n"; | |
55 | ||
56 | # Drop processed event from queue. | |
57 | $queue->dequeue(); | |
58 | } | |
59 | ||
60 | # XXX | |
61 | # Temporary workaround to reduce the load of the main process. | |
62 | sleep(1); | |
63 | } | |
64 | ||
65 | # | |
66 | ## Init function. | |
67 | # | |
68 | ## This function contains code which has to be executed while guardian | |
69 | ## is starting. | |
70 | # | |
71 | sub Init () { | |
6abac3d4 SS |
72 | # Setup IPC mechanism via Socket in an own thread. |
73 | threads->create(\&Socket); | |
74 | ||
88d9af2c SS |
75 | # Loop through the array of which files should be monitored and |
76 | # create a worker thread for each single one. | |
77 | foreach my $monitored_file (@monitored_files) { | |
78 | # Check if the file exists and is readable. | |
79 | if (-r "$monitored_file") { | |
80 | # Create worker thread for the file. | |
81 | threads->create(\&Worker,$monitored_file); | |
82 | } | |
83 | } | |
84 | } | |
85 | ||
86 | # | |
87 | ## Worker function. | |
88 | # | |
89 | ## This function is responsible for monitoring modifications of the given logfile, | |
90 | ## read them and pass them to the message parser. | |
91 | # | |
92 | ## To get file modifications the inotify subsystem of the linux kernel is used. | |
93 | # | |
94 | ## In order to prevent from permanently read and keep files opened, or dealing | |
95 | ## with huge logfiles, at initialization time of the worker process, the file will | |
96 | ## be opened once and the cursor position of the end of file (EOF) get stored. When | |
97 | ## reading any newly added lines from the file, we directly can jump to the last | |
98 | ## known position and get these lines. Afterwards, we store the current curser position | |
99 | ## again, so we can do it in this way over and over again. | |
100 | # | |
101 | ## All read lines get stored in an array, which will be passed to the Parser. | |
102 | # | |
103 | ## If any response (action) from the parser get recieved, it will be put into the | |
104 | ## shared event queue. | |
105 | # | |
106 | sub Worker ($) { | |
107 | my $file = @_[0]; | |
108 | ||
109 | # Get the fileposition. | |
110 | my $fileposition = &Init_fileposition("$file"); | |
111 | ||
112 | # Create inotify watcher. | |
113 | my $watcher = new Linux::Inotify2 or die "Could not use inotify. $!\n"; | |
114 | ||
115 | # Monitor the specified file. | |
116 | $watcher->watch("$file", IN_MODIFY) or die "Could not monitor $file. $!\n"; | |
117 | ||
118 | # Get all notifications. | |
119 | while ($watcher->read) { | |
120 | my @message = (); | |
121 | ||
122 | # Open the file. | |
123 | open (FILE, $file) or die "Could not open $file. $!\n"; | |
124 | ||
125 | # Seek to the last known position. | |
126 | seek (FILE, $fileposition, 0); | |
127 | ||
128 | # Get the log message. | |
129 | while (my $line = <FILE>) { | |
130 | # Remove any newlines. | |
131 | chomp $line; | |
132 | ||
133 | # Add all lines to the message array. | |
134 | push (@message, $line); | |
135 | } | |
136 | ||
137 | # Update fileposition. | |
138 | $fileposition = tell(FILE); | |
139 | ||
140 | # Close file. | |
141 | close(FILE); | |
142 | ||
143 | # Send filename and message to the parser, | |
144 | # which will return if an action has to be performed. | |
145 | my @action = &Guardian::Parser::Parser("$file", @message); | |
146 | ||
147 | # Send the action to the main process and put it into | |
148 | # the queue. | |
149 | if (@action) { | |
150 | # Lock the queue. | |
151 | lock($queue); | |
152 | ||
153 | # Put the required action into the queue. | |
154 | $queue->enqueue(@action); | |
155 | } | |
156 | } | |
157 | } | |
158 | ||
6abac3d4 SS |
159 | # |
160 | ## Socket function. | |
161 | # | |
162 | ## This function uses the Socket module to create and listen to an UNIX socket. | |
163 | ## It automatically accepts all incomming connections and pass the recieved | |
164 | ## data messages to the the Message_Parser function which is also part of the | |
165 | ## socket module. | |
166 | # | |
167 | ## If a valid command has been sent through the socket, the corresponding event | |
168 | ## will be enqueued into the shared event queue. | |
169 | # | |
170 | sub Socket () { | |
171 | # Create the Server socket by calling the responsible function. | |
172 | my $server = &Guardian::Socket::Server(); | |
173 | ||
174 | # Accept incomming connections from the socket. | |
175 | while (my $connection = $server->accept()) { | |
176 | # Autoflush the socket after the data | |
177 | # has been recieved. | |
178 | $connection->autoflush(1); | |
179 | ||
180 | # Gather all data from the connection. | |
181 | while (my $message = <$connection>) { | |
182 | # Remove any newlines. | |
183 | chomp($message); | |
184 | ||
185 | # Send the recieved data message to the | |
186 | # socket parser. | |
187 | my $action = &Guardian::Socket::Message_Parser($message); | |
188 | ||
189 | # If the parser returns to perform an action, | |
190 | # add it to the main event queue. | |
191 | if ($action) { | |
192 | # Lock the queue. | |
193 | lock($queue); | |
194 | ||
195 | # Enqueue the returned action. | |
196 | $queue->enqueue($action); | |
197 | } | |
198 | } | |
199 | } | |
200 | } | |
201 | ||
88d9af2c SS |
202 | # |
203 | ## Function for fileposition initialization. | |
204 | # | |
205 | ## This function is used to get the cursor position of the end of file (EOF) of | |
206 | ## a specified file. | |
207 | # | |
208 | ## In order to prevent from permanently read and keep files opened, or dealing | |
209 | ## with huge logfiles, at initialization time of the worker processes, the file will | |
210 | ## be opened once and the cursor position of the end of file (EOF) get stored. | |
211 | # | |
212 | sub Init_fileposition ($) { | |
213 | my $file = $_[0]; | |
214 | ||
215 | # Open the file. | |
216 | open(FILE, $file) or die "Could not open $file. $!\n"; | |
217 | ||
218 | # Just seek to the end of the file (EOF). | |
219 | seek(FILE, 0, 2); | |
220 | ||
221 | # Get and store the position. | |
222 | my $position = tell(FILE), | |
223 | ||
224 | # Close the file again. | |
225 | close(FILE); | |
226 | ||
227 | # Return the position. | |
228 | return $position; | |
229 | } |