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43e5396b DG |
1 | /* |
2 | * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com> | |
3 | * | |
4 | * This library is free software; you can redistribute it and/or modify it | |
5 | * under the terms of the GNU Lesser General Public License, version 2.1 only, | |
6 | * as published by the Free Software Foundation. | |
7 | * | |
8 | * This library is distributed in the hope that it will be useful, but WITHOUT | |
9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License | |
11 | * for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU Lesser General Public License | |
14 | * along with this library; if not, write to the Free Software Foundation, | |
15 | * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
16 | */ | |
17 | ||
18 | package org.lttng.ust.jul; | |
19 | ||
20 | import java.io.IOException; | |
21 | import java.io.FileNotFoundException; | |
22 | import java.io.InputStream; | |
23 | import java.io.BufferedReader; | |
24 | import java.io.FileReader; | |
25 | import java.util.concurrent.Semaphore; | |
26 | import java.util.logging.FileHandler; | |
27 | import java.util.logging.Handler; | |
28 | import java.util.logging.Level; | |
29 | import java.util.logging.Logger; | |
30 | import java.util.logging.LogManager; | |
31 | import java.util.Enumeration; | |
32 | ||
33 | public class LTTngAgent { | |
34 | private static LTTngLogHandler lttngHandler; | |
35 | private static LogManager logManager; | |
36 | private static LTTngThread lttngThread; | |
37 | private static Thread sessiondTh; | |
38 | ||
39 | /* Singleton agent object. */ | |
40 | private static LTTngAgent curAgent = null; | |
41 | ||
42 | /* Indicate if this object has been initialized. */ | |
43 | private static boolean initialized = false; | |
44 | ||
45 | private static Semaphore registerSem; | |
46 | ||
47 | private static final String sessiondAddr = "127.0.0.1"; | |
48 | private static final int sessiondPort = 5345; | |
49 | ||
50 | private static final String rootPortFile = "/var/run/lttng/jul.port"; | |
51 | private static final String userPortFile = "/.lttng/jul.port"; | |
52 | ||
53 | /* | |
54 | * Constructor is private. This is a singleton and a reference should be | |
55 | * acquired using getLTTngAgent(). | |
56 | */ | |
57 | private LTTngAgent() throws IOException { | |
58 | this.logManager = LogManager.getLogManager(); | |
59 | this.lttngHandler = new LTTngLogHandler(this.logManager); | |
60 | this.registerSem = new Semaphore(0, true); | |
61 | } | |
62 | ||
63 | private void removeHandlers() throws SecurityException, IOException { | |
64 | String loggerName; | |
65 | Logger logger; | |
66 | ||
67 | Enumeration list = this.logManager.getLoggerNames(); | |
68 | while (list.hasMoreElements()) { | |
69 | loggerName = list.nextElement().toString(); | |
70 | /* Somehow there is always an empty string at the end. */ | |
71 | if (loggerName == "") { | |
72 | continue; | |
73 | } | |
74 | ||
75 | logger = this.logManager.getLogger(loggerName); | |
76 | logger.removeHandler(this.lttngHandler); | |
77 | } | |
78 | } | |
79 | ||
80 | private int getUID() throws IOException { | |
81 | int uid; | |
82 | byte b[] = new byte[4]; | |
83 | String userName = System.getProperty("user.name"); | |
84 | String command = "id -u " + userName; | |
85 | Process child = Runtime.getRuntime().exec(command); | |
86 | InputStream in = child.getInputStream(); | |
87 | ||
88 | in.read(b); | |
89 | uid = Integer.parseInt(new String(b).trim(), 10); | |
90 | in.close(); | |
91 | ||
92 | return uid; | |
93 | } | |
94 | ||
95 | private String getHomePath() { | |
96 | return System.getProperty("user.home"); | |
97 | } | |
98 | ||
99 | private int getPortFromFile() throws IOException { | |
100 | int port; | |
101 | int uid = getUID(); | |
102 | String path; | |
103 | BufferedReader br; | |
104 | ||
105 | /* Check if root or not, it tells where to get the port file. */ | |
106 | if (uid == 0) { | |
107 | path = rootPortFile; | |
108 | } else { | |
109 | path = new String(getHomePath() + userPortFile); | |
110 | } | |
111 | ||
112 | try { | |
113 | br = new BufferedReader(new FileReader(path)); | |
114 | String line = br.readLine(); | |
115 | port = Integer.parseInt(line, 10); | |
116 | if (port < 0 || port > 65535) { | |
117 | port = sessiondPort; | |
118 | } | |
119 | br.close(); | |
120 | } catch (FileNotFoundException e) { | |
121 | port = sessiondPort; | |
122 | } | |
123 | ||
124 | return port; | |
125 | } | |
126 | ||
127 | /* | |
128 | * Public getter to acquire a reference to this singleton object. | |
129 | */ | |
130 | public static synchronized LTTngAgent getLTTngAgent() throws IOException { | |
131 | if (curAgent == null) { | |
132 | curAgent = new LTTngAgent(); | |
133 | curAgent.init(); | |
134 | } | |
135 | ||
136 | return curAgent; | |
137 | } | |
138 | ||
139 | /* | |
140 | * Initialize LTTngAgent. This will attach the log handler to all Logger | |
141 | * returned by the logManager. | |
142 | */ | |
143 | private synchronized void init() throws SecurityException, IOException { | |
144 | if (this.initialized) { | |
145 | return; | |
146 | } | |
147 | ||
148 | this.lttngThread = new LTTngThread(this.sessiondAddr, | |
149 | getPortFromFile(), this.lttngHandler, this.registerSem); | |
150 | this.sessiondTh = new Thread(lttngThread); | |
151 | this.sessiondTh.start(); | |
152 | ||
153 | this.initialized = true; | |
154 | ||
155 | /* Wait for the registration to end. */ | |
156 | try { | |
157 | this.registerSem.acquire(); | |
158 | } catch (InterruptedException e) { | |
159 | e.printStackTrace(); | |
160 | } | |
161 | } | |
162 | ||
163 | public void dispose() throws IOException { | |
164 | this.lttngThread.dispose(); | |
165 | ||
166 | /* Make sure there is no more LTTng handler attach to logger(s). */ | |
167 | this.removeHandlers(); | |
168 | ||
169 | try { | |
170 | this.sessiondTh.join(); | |
171 | } catch (InterruptedException e) { | |
172 | e.printStackTrace(); | |
173 | } | |
174 | } | |
175 | } |