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 import jdk.internal.vm.VMSupport;
31
32 /**
33 * Class to provide translations from the local Vm Identifier
34 * name space into the file system name space and vice-versa.
35 * <p>
36 * Provides a factory for creating a File object to the backing
37 * store file for instrumentation shared memory region for a JVM
38 * identified by its Local Java Virtual Machine Identifier, or
39 * <em>lvmid</em>.
40 *
41 * @author Brian Doherty
42 * @since 1.5
43 * @see java.io.File
44 */
45 public class PerfDataFile {
46 private PerfDataFile() { };
47
48 /**
49 * The name of the of the system dependent temporary directory
50 */
51 public static final String tmpDirName;
52
53 /**
54 * The file name prefix for PerfData shared memory files.
55 * <p>
56 * This prefix must be kept in sync with the prefix used by the JVM.
57 */
58 public static final String dirNamePrefix = "hsperfdata_";
59
60 /**
61 * The directory name pattern for the user directories.
62 */
63 public static final String userDirNamePattern = "hsperfdata_\\S*";
64
65 /**
66 * The file name pattern for PerfData shared memory files.
67 * <p>
68 * This pattern must be kept in synch with the file name pattern
69 * used by the 1.4.2 and later HotSpot JVM.
70 */
71 public static final String fileNamePattern = "^[0-9]+$";
72
73 /**
74 * The file name pattern for 1.4.1 PerfData shared memory files.
75 * <p>
76 * This pattern must be kept in synch with the file name pattern
77 * used by the 1.4.1 HotSpot JVM.
78 */
79 public static final String tmpFileNamePattern =
80 "^hsperfdata_[0-9]+(_[1-2]+)?$";
81
82
83 /**
84 * Get a File object for the instrumentation backing store file
85 * for the JVM identified by the given local Vm Identifier.
86 * <p>
87 * This method looks for the most up to date backing store file for
88 * the given {@code lvmid}. It will search all the user specific
89 * directories in the temporary directory for the host operating
90 * system, which may be influenced by platform specific environment
91 * variables.
92 *
93 * @param lvmid the local Java Virtual Machine Identifier for the target
94 * @return File - a File object to the backing store file for the named
95 * shared memory region of the target JVM.
96 * @see java.io.File
97 * @see #getTempDirectory()
98 */
99 public static File getFile(int lvmid) {
100 if (lvmid == 0) {
101 /*
102 * lvmid == 0 is used to indicate the current Java Virtual Machine.
103 * If the SDK provided an API to get a unique Java Virtual Machine
104 * identifier, then a filename could be constructed with that
105 * identifier. In absence of such an api, return null.
106 */
107 return null;
108 }
109
110 /*
111 * iterate over all files in all directories in tmpDirName that
112 * match the file name patterns.
113 */
114 File tmpDir = new File(tmpDirName);
115 String[] files = tmpDir.list(new FilenameFilter() {
116 public boolean accept(File dir, String name) {
117 if (!name.startsWith(dirNamePrefix)) {
118 return false;
119 }
120 File candidate = new File(dir, name);
121 return ((candidate.isDirectory() || candidate.isFile())
122 && candidate.canRead());
123 }
124 });
125
126 long newestTime = 0;
127 File newest = null;
128
129 for (int i = 0; i < files.length; i++) {
130 File f = new File(tmpDirName + files[i]);
131 File candidate = null;
132
133 if (f.exists() && f.isDirectory()) {
134 /*
135 * found a directory matching the name patterns. This
136 * is a 1.4.2 hsperfdata_<user> directory. Check for
137 * file named <lvmid> in that directory
138 */
139 String name = Integer.toString(lvmid);
140 candidate = new File(f.getName(), name);
141
142 } else if (f.exists() && f.isFile()) {
143 /*
144 * found a file matching the name patterns. This
145 * is a 1.4.1 hsperfdata_<lvmid> file.
146 */
147 candidate = f;
148
149 } else {
150 // unexpected - let conditional below filter this one out
151 candidate = f;
152 }
153
154 if (candidate.exists() && candidate.isFile()
155 && candidate.canRead()) {
156 long modTime = candidate.lastModified();
157 if (modTime >= newestTime) {
158 newestTime = modTime;
159 newest = candidate;
160 }
161 }
162 }
163 return newest;
164 }
165
166 /**
167 * Return the File object for the backing store file for the specified Java
168 * Virtual Machine.
169 * <p>
170 * This method looks for the most up to date backing store file for
171 * the JVM identified by the given user name and lvmid. The directory
172 * searched is the temporary directory for the host operating system,
173 * which may be influenced by environment variables.
174 *
175 * @param user the user name
176 * @param lvmid the local Java Virtual Machine Identifier for the target
177 * @return File - a File object to the backing store file for the named
178 * shared memory region of the target JVM.
179 * @see java.io.File
180 * @see #getTempDirectory()
181 */
182 public static File getFile(String user, int lvmid) {
183 if (lvmid == 0) {
184 /*
185 * lvmid == 0 is used to indicate the current Java Virtual Machine.
186 * If the SDK provided an API to get a unique Java Virtual Machine
187 * identifier, then a filename could be constructed with that
188 * identifier. In absence of such an api, return null.
189 */
190 return null;
191 }
192
193 // first try for 1.4.2 and later JVMs
194 String basename = getTempDirectory(user) + Integer.toString(lvmid);
195 File f = new File(basename);
196
197 if (f.exists() && f.isFile() && f.canRead()) {
198 return f;
199 }
200
201 // No hit on 1.4.2 JVMs, try 1.4.1 files
202 long newestTime = 0;
203 File newest = null;
204 for (int i = 0; i < 2; i++) {
205 if (i == 0) {
206 basename = getTempDirectory() + Integer.toString(lvmid);
207 } else {
208 basename = getTempDirectory() + Integer.toString(lvmid)
209 + Integer.toString(i);
210 }
211
212 f = new File(basename);
213
214 if (f.exists() && f.isFile() && f.canRead()) {
215 long modTime = f.lastModified();
216 if (modTime >= newestTime) {
217 newestTime = modTime;
218 newest = f;
219 }
220 }
221 }
222 return newest;
223 }
224
225 /**
226 * Method to extract a local Java Virtual Machine Identifier from the
227 * file name of the given File object.
228 *
229 * @param file A File object representing the name of a
230 * shared memory region for a target JVM
231 * @return int - the local Java Virtual Machine Identifier for the target
232 * associated with the file
233 * @throws java.lang.IllegalArgumentException Thrown if the file name
234 * does not conform to the expected pattern
235 */
236 public static int getLocalVmId(File file) {
237 try {
238 // try 1.4.2 and later format first
239 return Integer.parseInt(file.getName());
240 } catch (NumberFormatException e) { }
241
242 // now try the 1.4.1 format
243 String name = file.getName();
244 if (name.startsWith(dirNamePrefix)) {
245 int first = name.indexOf('_');
246 int last = name.lastIndexOf('_');
247 try {
248 if (first == last) {
249 return Integer.parseInt(name.substring(first + 1));
250 } else {
251 return Integer.parseInt(name.substring(first + 1, last));
252 }
253 } catch (NumberFormatException e) { }
254 }
255 throw new IllegalArgumentException("file name does not match pattern");
256 }
257
258 /**
259 * Return the name of the temporary directory being searched for
260 * HotSpot PerfData backing store files.
261 * <p>
262 * This method generally returns the value of the java.io.tmpdir
263 * property. However, on some platforms it may return a different
264 * directory, as the JVM implementation may store the PerfData backing
265 * store files in a different directory for performance reasons.
266 *
267 * @return String - the name of the temporary directory.
268 */
269 public static String getTempDirectory() {
270 return tmpDirName;
271 }
272
273 /**
274 * Return the name of the temporary directory to be searched
275 * for HotSpot PerfData backing store files for a given user.
276 * <p>
277 * This method generally returns the name of a subdirectory of
278 * the directory indicated in the java.io.tmpdir property. However,
279 * on some platforms it may return a different directory, as the
280 * JVM implementation may store the PerfData backing store files
281 * in a different directory for performance reasons.
282 *
283 * @return String - the name of the temporary directory.
284 */
285 public static String getTempDirectory(String user) {
286 return tmpDirName + dirNamePrefix + user + File.separator;
287 }
288
289 static {
290 /*
291 * For this to work, the target VM and this code need to use
292 * the same directory. Instead of guessing which directory the
293 * VM is using, we will ask.
294 */
295 String tmpdir = VMSupport.getVMTemporaryDirectory();
296
297 /*
298 * Assure that the string returned has a trailing File.separator
299 * character. This check was added because the Linux implementation
300 * changed such that the java.io.tmpdir string no longer terminates
301 * with a File.separator character.
302 */
303 if (tmpdir.lastIndexOf(File.separator) != (tmpdir.length()-1)) {
304 tmpdir = tmpdir + File.separator;
305 }
306 tmpDirName = tmpdir;
307 }
308 }