1 /*
2 * Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package sun.jvmstat.perfdata.monitor.protocol.local;
27
28 import java.io.File;
29 import java.io.FilenameFilter;
30
31 /**
32 * Class to provide translations from the local Vm Identifier
33 * name space into the file system name space and vice-versa.
34 * <p>
35 * Provides a factory for creating a File object to the backing
36 * store file for instrumentation shared memory region for a JVM
37 * identified by its Local Java Virtual Machine Identifier, or
38 * <em>lvmid</em>.
39 *
40 * @author Brian Doherty
41 * @since 1.5
42 * @see java.io.File
43 */
44 public class PerfDataFile {
45 private PerfDataFile() { };
46
47 /**
48 * The name of the of the system dependent temporary directory
49 */
50 public static final String tmpDirName;
51
52 /**
53 * The file name prefix for PerfData shared memory files.
54 * <p>
55 * This prefix must be kept in sync with the prefix used by the JVM.
56 */
57 public static final String dirNamePrefix = "hsperfdata_";
58
59 /**
60 * The directory name pattern for the user directories.
61 */
62 public static final String userDirNamePattern = "hsperfdata_\\S*";
63
64 /**
65 * The file name pattern for PerfData shared memory files.
66 * <p>
67 * This pattern must be kept in synch with the file name pattern
68 * used by the 1.4.2 and later HotSpot JVM.
69 */
70 public static final String fileNamePattern = "^[0-9]+$";
71
72 /**
73 * The file name pattern for 1.4.1 PerfData shared memory files.
74 * <p>
75 * This pattern must be kept in synch with the file name pattern
76 * used by the 1.4.1 HotSpot JVM.
77 */
78 public static final String tmpFileNamePattern =
79 "^hsperfdata_[0-9]+(_[1-2]+)?$";
80
81
82 /**
83 * Get a File object for the instrumentation backing store file
84 * for the JVM identified by the given local Vm Identifier.
85 * <p>
86 * This method looks for the most up to date backing store file for
87 * the given <tt>lvmid</tt>. It will search all the user specific
88 * directories in the temporary directory for the host operating
89 * system, which may be influenced by platform specific environment
90 * variables.
91 *
92 * @param lvmid the local Java Virtual Machine Identifier for the target
93 * @return File - a File object to the backing store file for the named
94 * shared memory region of the target JVM.
95 * @see java.io.File
96 * @see #getTempDirectory()
97 */
98 public static File getFile(int lvmid) {
99 if (lvmid == 0) {
100 /*
101 * lvmid == 0 is used to indicate the current Java Virtual Machine.
102 * If the SDK provided an API to get a unique Java Virtual Machine
103 * identifier, then a filename could be constructed with that
104 * identifier. In absence of such an api, return null.
105 */
106 return null;
107 }
108
109 /*
110 * iterate over all files in all directories in tmpDirName that
111 * match the file name patterns.
112 */
113 File tmpDir = new File(tmpDirName);
114 String[] files = tmpDir.list(new FilenameFilter() {
115 public boolean accept(File dir, String name) {
116 if (!name.startsWith(dirNamePrefix)) {
117 return false;
118 }
119 File candidate = new File(dir, name);
120 return ((candidate.isDirectory() || candidate.isFile())
121 && candidate.canRead());
122 }
123 });
124
125 long newestTime = 0;
126 File newest = null;
127
128 for (int i = 0; i < files.length; i++) {
129 File f = new File(tmpDirName + files[i]);
130 File candidate = null;
131
132 if (f.exists() && f.isDirectory()) {
133 /*
134 * found a directory matching the name patterns. This
135 * is a 1.4.2 hsperfdata_<user> directory. Check for
136 * file named <lvmid> in that directory
137 */
138 String name = Integer.toString(lvmid);
139 candidate = new File(f.getName(), name);
140
141 } else if (f.exists() && f.isFile()) {
142 /*
143 * found a file matching the name patterns. This
144 * is a 1.4.1 hsperfdata_<lvmid> file.
145 */
146 candidate = f;
147
148 } else {
149 // unexpected - let conditional below filter this one out
150 candidate = f;
151 }
152
153 if (candidate.exists() && candidate.isFile()
154 && candidate.canRead()) {
155 long modTime = candidate.lastModified();
156 if (modTime >= newestTime) {
157 newestTime = modTime;
158 newest = candidate;
159 }
160 }
161 }
162 return newest;
163 }
164
165 /**
166 * Return the File object for the backing store file for the specified Java
167 * Virtual Machine.
168 * <p>
169 * This method looks for the most up to date backing store file for
170 * the JVM identified by the given user name and lvmid. The directory
171 * searched is the temporary directory for the host operating system,
172 * which may be influenced by environment variables.
173 *
174 * @param user the user name
175 * @param lvmid the local Java Virtual Machine Identifier for the target
176 * @return File - a File object to the backing store file for the named
177 * shared memory region of the target JVM.
178 * @see java.io.File
179 * @see #getTempDirectory()
180 */
181 public static File getFile(String user, int lvmid) {
182 if (lvmid == 0) {
183 /*
184 * lvmid == 0 is used to indicate the current Java Virtual Machine.
185 * If the SDK provided an API to get a unique Java Virtual Machine
186 * identifier, then a filename could be constructed with that
187 * identifier. In absence of such an api, return null.
188 */
189 return null;
190 }
191
192 // first try for 1.4.2 and later JVMs
193 String basename = getTempDirectory(user) + Integer.toString(lvmid);
194 File f = new File(basename);
195
196 if (f.exists() && f.isFile() && f.canRead()) {
197 return f;
198 }
199
200 // No hit on 1.4.2 JVMs, try 1.4.1 files
201 long newestTime = 0;
202 File newest = null;
203 for (int i = 0; i < 2; i++) {
204 if (i == 0) {
205 basename = getTempDirectory() + Integer.toString(lvmid);
206 } else {
207 basename = getTempDirectory() + Integer.toString(lvmid)
208 + Integer.toString(i);
209 }
210
211 f = new File(basename);
212
213 if (f.exists() && f.isFile() && f.canRead()) {
214 long modTime = f.lastModified();
215 if (modTime >= newestTime) {
216 newestTime = modTime;
217 newest = f;
218 }
219 }
220 }
221 return newest;
222 }
223
224 /**
225 * Method to extract a local Java Virtual Machine Identifier from the
226 * file name of the given File object.
227 *
228 * @param file A File object representing the name of a
229 * shared memory region for a target JVM
230 * @return int - the local Java Virtual Machine Identifier for the target
231 * associated with the file
232 * @throws java.lang.IllegalArgumentException Thrown if the file name
233 * does not conform to the expected pattern
234 */
235 public static int getLocalVmId(File file) {
236 int lvmid = 0;
237
238 try {
239 // try 1.4.2 and later format first
240 return Integer.parseInt(file.getName());
241 } catch (NumberFormatException e) { }
242
243 // now try the 1.4.1 format
244 String name = file.getName();
245 if (name.startsWith(dirNamePrefix)) {
246 int first = name.indexOf('_');
247 int last = name.lastIndexOf('_');
248 try {
249 if (first == last) {
250 return Integer.parseInt(name.substring(first + 1));
251 } else {
252 return Integer.parseInt(name.substring(first + 1, last));
253 }
254 } catch (NumberFormatException e) { }
255 }
256 throw new IllegalArgumentException("file name does not match pattern");
257 }
258
259 /**
260 * Return the name of the temporary directory being searched for
261 * HotSpot PerfData backing store files.
262 * <p>
263 * This method generally returns the value of the java.io.tmpdir
264 * property. However, on some platforms it may return a different
265 * directory, as the JVM implementation may store the PerfData backing
266 * store files in a different directory for performance reasons.
267 *
268 * @return String - the name of the temporary directory.
269 */
270 public static String getTempDirectory() {
271 return tmpDirName;
272 }
273
274 /**
275 * Return the name of the temporary directory to be searched
276 * for HotSpot PerfData backing store files for a given user.
277 * <p>
278 * This method generally returns the name of a subdirectory of
279 * the directory indicated in the java.io.tmpdir property. However,
280 * on some platforms it may return a different directory, as the
281 * JVM implementation may store the PerfData backing store files
282 * in a different directory for performance reasons.
283 *
284 * @return String - the name of the temporary directory.
285 */
286 public static String getTempDirectory(String user) {
287 return tmpDirName + dirNamePrefix + user + File.separator;
288 }
289
290 /*
291 * this static initializer would not be necessary if the
292 * Solaris java.io.tmpdir property were set to /tmp by default
293 */
294 static {
295 /*
296 * Why is java.io.tmpdir on Solaris set to "/var/tmp/" when the
297 * HotSpot JVM os:get_temp_path() method returns "/tmp/"
298 *
299 * Why do Solaris and Windows return a string with a trailing
300 * file separator character where as Linix does not? (this change
301 * seems to have occurred sometime during hopper beta)
302 */
303 String tmpdir = System.getProperty("java.io.tmpdir");
304
305 if (tmpdir.compareTo("/var/tmp/") == 0) {
306 /*
307 * shared memory files are created in /tmp. Interestingly,
308 * java.io.tmpdir is set to "/var/tmp/" on Solaris and Linux,
309 * but os::get_temp_directory() is set to "/tmp/" on these
310 * platforms. the java.io.logging packages also makes reference
311 * to java.io.tmpdir.
312 */
313 tmpdir = "/tmp/";
314 }
315
316 /*
317 * Assure that the string returned has a trailing File.separator
318 * character. This check was added because the Linux implementation
319 * changed such that the java.io.tmpdir string no longer terminates
320 * with a File.separator character.
321 */
322 if (tmpdir.lastIndexOf(File.separator) != (tmpdir.length()-1)) {
323 tmpdir = tmpdir + File.separator;
324 }
325 tmpDirName = tmpdir;
326 }
327 }