1 /*
2 * Copyright (c) 2000, 2012, 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 java.util.logging;
27
28 import static java.nio.file.StandardOpenOption.CREATE_NEW;
29 import static java.nio.file.StandardOpenOption.WRITE;
30
31 import java.io.BufferedOutputStream;
32 import java.io.File;
33 import java.io.FileOutputStream;
34 import java.io.IOException;
35 import java.io.OutputStream;
36 import java.nio.channels.FileChannel;
37 import java.nio.file.FileAlreadyExistsException;
38 import java.nio.file.Paths;
39 import java.security.AccessController;
40 import java.security.PrivilegedAction;
41
42 /**
43 * Simple file logging <tt>Handler</tt>.
44 * <p>
45 * The <tt>FileHandler</tt> can either write to a specified file,
46 * or it can write to a rotating set of files.
47 * <p>
48 * For a rotating set of files, as each file reaches a given size
49 * limit, it is closed, rotated out, and a new file opened.
50 * Successively older files are named by adding "0", "1", "2",
51 * etc. into the base filename.
52 * <p>
53 * By default buffering is enabled in the IO libraries but each log
54 * record is flushed out when it is complete.
55 * <p>
56 * By default the <tt>XMLFormatter</tt> class is used for formatting.
57 * <p>
58 * <b>Configuration:</b>
59 * By default each <tt>FileHandler</tt> is initialized using the following
60 * <tt>LogManager</tt> configuration properties where <tt><handler-name></tt>
61 * refers to the fully-qualified class name of the handler.
62 * If properties are not defined
63 * (or have invalid values) then the specified default values are used.
64 * <ul>
65 * <li> <handler-name>.level
66 * specifies the default level for the <tt>Handler</tt>
67 * (defaults to <tt>Level.ALL</tt>). </li>
68 * <li> <handler-name>.filter
69 * specifies the name of a <tt>Filter</tt> class to use
70 * (defaults to no <tt>Filter</tt>). </li>
71 * <li> <handler-name>.formatter
72 * specifies the name of a <tt>Formatter</tt> class to use
73 * (defaults to <tt>java.util.logging.XMLFormatter</tt>) </li>
74 * <li> <handler-name>.encoding
75 * the name of the character set encoding to use (defaults to
76 * the default platform encoding). </li>
77 * <li> <handler-name>.limit
78 * specifies an approximate maximum amount to write (in bytes)
79 * to any one file. If this is zero, then there is no limit.
80 * (Defaults to no limit). </li>
81 * <li> <handler-name>.count
82 * specifies how many output files to cycle through (defaults to 1). </li>
83 * <li> <handler-name>.pattern
84 * specifies a pattern for generating the output file name. See
85 * below for details. (Defaults to "%h/java%u.log"). </li>
86 * <li> <handler-name>.append
87 * specifies whether the FileHandler should append onto
88 * any existing files (defaults to false). </li>
89 * </ul>
90 * <p>
91 * For example, the properties for {@code FileHandler} would be:
92 * <ul>
93 * <li> java.util.logging.FileHandler.level=INFO </li>
94 * <li> java.util.logging.FileHandler.formatter=java.util.logging.SimpleFormatter </li>
95 * </ul>
96 * <p>
97 * For a custom handler, e.g. com.foo.MyHandler, the properties would be:
98 * <ul>
99 * <li> com.foo.MyHandler.level=INFO </li>
100 * <li> com.foo.MyHandler.formatter=java.util.logging.SimpleFormatter </li>
101 * </ul>
102 * <p>
103 * A pattern consists of a string that includes the following special
104 * components that will be replaced at runtime:
105 * <ul>
106 * <li> "/" the local pathname separator </li>
107 * <li> "%t" the system temporary directory </li>
108 * <li> "%h" the value of the "user.home" system property </li>
109 * <li> "%g" the generation number to distinguish rotated logs </li>
110 * <li> "%u" a unique number to resolve conflicts </li>
111 * <li> "%%" translates to a single percent sign "%" </li>
112 * </ul>
113 * If no "%g" field has been specified and the file count is greater
114 * than one, then the generation number will be added to the end of
115 * the generated filename, after a dot.
116 * <p>
117 * Thus for example a pattern of "%t/java%g.log" with a count of 2
118 * would typically cause log files to be written on Solaris to
119 * /var/tmp/java0.log and /var/tmp/java1.log whereas on Windows 95 they
120 * would be typically written to C:\TEMP\java0.log and C:\TEMP\java1.log
121 * <p>
122 * Generation numbers follow the sequence 0, 1, 2, etc.
123 * <p>
124 * Normally the "%u" unique field is set to 0. However, if the <tt>FileHandler</tt>
125 * tries to open the filename and finds the file is currently in use by
126 * another process it will increment the unique number field and try
127 * again. This will be repeated until <tt>FileHandler</tt> finds a file name that
128 * is not currently in use. If there is a conflict and no "%u" field has
129 * been specified, it will be added at the end of the filename after a dot.
130 * (This will be after any automatically added generation number.)
131 * <p>
132 * Thus if three processes were all trying to log to fred%u.%g.txt then
133 * they might end up using fred0.0.txt, fred1.0.txt, fred2.0.txt as
134 * the first file in their rotating sequences.
135 * <p>
136 * Note that the use of unique ids to avoid conflicts is only guaranteed
137 * to work reliably when using a local disk file system.
138 *
139 * @since 1.4
140 */
141
142 public class FileHandler extends StreamHandler {
143 private MeteredStream meter;
144 private boolean append;
145 private int limit; // zero => no limit.
146 private int count;
147 private String pattern;
148 private String lockFileName;
149 private FileChannel lockFileChannel;
150 private File files[];
151 private static final int MAX_LOCKS = 100;
152 private static java.util.HashMap<String, String> locks = new java.util.HashMap<>();
153
154 /**
155 * A metered stream is a subclass of OutputStream that
156 * (a) forwards all its output to a target stream
157 * (b) keeps track of how many bytes have been written
158 */
159 private class MeteredStream extends OutputStream {
160 OutputStream out;
161 int written;
162
163 MeteredStream(OutputStream out, int written) {
164 this.out = out;
165 this.written = written;
166 }
167
168 public void write(int b) throws IOException {
169 out.write(b);
170 written++;
171 }
172
173 public void write(byte buff[]) throws IOException {
174 out.write(buff);
175 written += buff.length;
176 }
177
178 public void write(byte buff[], int off, int len) throws IOException {
179 out.write(buff,off,len);
180 written += len;
181 }
182
183 public void flush() throws IOException {
184 out.flush();
185 }
186
187 public void close() throws IOException {
188 out.close();
189 }
190 }
191
192 private void open(File fname, boolean append) throws IOException {
193 int len = 0;
194 if (append) {
195 len = (int)fname.length();
196 }
197 FileOutputStream fout = new FileOutputStream(fname.toString(), append);
198 BufferedOutputStream bout = new BufferedOutputStream(fout);
199 meter = new MeteredStream(bout, len);
200 setOutputStream(meter);
201 }
202
203 /**
204 * Configure a FileHandler from LogManager properties and/or default values
205 * as specified in the class javadoc.
206 */
207 private void configure() {
208 LogManager manager = LogManager.getLogManager();
209
210 String cname = getClass().getName();
211
212 pattern = manager.getStringProperty(cname + ".pattern", "%h/java%u.log");
213 limit = manager.getIntProperty(cname + ".limit", 0);
214 if (limit < 0) {
215 limit = 0;
216 }
217 count = manager.getIntProperty(cname + ".count", 1);
218 if (count <= 0) {
219 count = 1;
220 }
221 append = manager.getBooleanProperty(cname + ".append", false);
222 setLevel(manager.getLevelProperty(cname + ".level", Level.ALL));
223 setFilter(manager.getFilterProperty(cname + ".filter", null));
224 setFormatter(manager.getFormatterProperty(cname + ".formatter", new XMLFormatter()));
225 try {
226 setEncoding(manager.getStringProperty(cname +".encoding", null));
227 } catch (Exception ex) {
228 try {
229 setEncoding(null);
230 } catch (Exception ex2) {
231 // doing a setEncoding with null should always work.
232 // assert false;
233 }
234 }
235 }
236
237
238 /**
239 * Construct a default <tt>FileHandler</tt>. This will be configured
240 * entirely from <tt>LogManager</tt> properties (or their default values).
241 * <p>
242 * @exception IOException if there are IO problems opening the files.
243 * @exception SecurityException if a security manager exists and if
244 * the caller does not have <tt>LoggingPermission("control"))</tt>.
245 * @exception NullPointerException if pattern property is an empty String.
246 */
247 public FileHandler() throws IOException, SecurityException {
248 checkPermission();
249 configure();
250 openFiles();
251 }
252
253 /**
254 * Initialize a <tt>FileHandler</tt> to write to the given filename.
255 * <p>
256 * The <tt>FileHandler</tt> is configured based on <tt>LogManager</tt>
257 * properties (or their default values) except that the given pattern
258 * argument is used as the filename pattern, the file limit is
259 * set to no limit, and the file count is set to one.
260 * <p>
261 * There is no limit on the amount of data that may be written,
262 * so use this with care.
263 *
264 * @param pattern the name of the output file
265 * @exception IOException if there are IO problems opening the files.
266 * @exception SecurityException if a security manager exists and if
267 * the caller does not have <tt>LoggingPermission("control")</tt>.
268 * @exception IllegalArgumentException if pattern is an empty string
269 */
270 public FileHandler(String pattern) throws IOException, SecurityException {
271 if (pattern.length() < 1 ) {
272 throw new IllegalArgumentException();
273 }
274 checkPermission();
275 configure();
276 this.pattern = pattern;
277 this.limit = 0;
278 this.count = 1;
279 openFiles();
280 }
281
282 /**
283 * Initialize a <tt>FileHandler</tt> to write to the given filename,
284 * with optional append.
285 * <p>
286 * The <tt>FileHandler</tt> is configured based on <tt>LogManager</tt>
287 * properties (or their default values) except that the given pattern
288 * argument is used as the filename pattern, the file limit is
289 * set to no limit, the file count is set to one, and the append
290 * mode is set to the given <tt>append</tt> argument.
291 * <p>
292 * There is no limit on the amount of data that may be written,
293 * so use this with care.
294 *
295 * @param pattern the name of the output file
296 * @param append specifies append mode
297 * @exception IOException if there are IO problems opening the files.
298 * @exception SecurityException if a security manager exists and if
299 * the caller does not have <tt>LoggingPermission("control")</tt>.
300 * @exception IllegalArgumentException if pattern is an empty string
301 */
302 public FileHandler(String pattern, boolean append) throws IOException,
303 SecurityException {
304 if (pattern.length() < 1 ) {
305 throw new IllegalArgumentException();
306 }
307 checkPermission();
308 configure();
309 this.pattern = pattern;
310 this.limit = 0;
311 this.count = 1;
312 this.append = append;
313 openFiles();
314 }
315
316 /**
317 * Initialize a <tt>FileHandler</tt> to write to a set of files. When
318 * (approximately) the given limit has been written to one file,
319 * another file will be opened. The output will cycle through a set
320 * of count files.
321 * <p>
322 * The <tt>FileHandler</tt> is configured based on <tt>LogManager</tt>
323 * properties (or their default values) except that the given pattern
324 * argument is used as the filename pattern, the file limit is
325 * set to the limit argument, and the file count is set to the
326 * given count argument.
327 * <p>
328 * The count must be at least 1.
329 *
330 * @param pattern the pattern for naming the output file
331 * @param limit the maximum number of bytes to write to any one file
332 * @param count the number of files to use
333 * @exception IOException if there are IO problems opening the files.
334 * @exception SecurityException if a security manager exists and if
335 * the caller does not have <tt>LoggingPermission("control")</tt>.
336 * @exception IllegalArgumentException if limit < 0, or count < 1.
337 * @exception IllegalArgumentException if pattern is an empty string
338 */
339 public FileHandler(String pattern, int limit, int count)
340 throws IOException, SecurityException {
341 if (limit < 0 || count < 1 || pattern.length() < 1) {
342 throw new IllegalArgumentException();
343 }
344 checkPermission();
345 configure();
346 this.pattern = pattern;
347 this.limit = limit;
348 this.count = count;
349 openFiles();
350 }
351
352 /**
353 * Initialize a <tt>FileHandler</tt> to write to a set of files
354 * with optional append. When (approximately) the given limit has
355 * been written to one file, another file will be opened. The
356 * output will cycle through a set of count files.
357 * <p>
358 * The <tt>FileHandler</tt> is configured based on <tt>LogManager</tt>
359 * properties (or their default values) except that the given pattern
360 * argument is used as the filename pattern, the file limit is
361 * set to the limit argument, and the file count is set to the
362 * given count argument, and the append mode is set to the given
363 * <tt>append</tt> argument.
364 * <p>
365 * The count must be at least 1.
366 *
367 * @param pattern the pattern for naming the output file
368 * @param limit the maximum number of bytes to write to any one file
369 * @param count the number of files to use
370 * @param append specifies append mode
371 * @exception IOException if there are IO problems opening the files.
372 * @exception SecurityException if a security manager exists and if
373 * the caller does not have <tt>LoggingPermission("control")</tt>.
374 * @exception IllegalArgumentException if limit < 0, or count < 1.
375 * @exception IllegalArgumentException if pattern is an empty string
376 *
377 */
378 public FileHandler(String pattern, int limit, int count, boolean append)
379 throws IOException, SecurityException {
380 if (limit < 0 || count < 1 || pattern.length() < 1) {
381 throw new IllegalArgumentException();
382 }
383 checkPermission();
384 configure();
385 this.pattern = pattern;
386 this.limit = limit;
387 this.count = count;
388 this.append = append;
389 openFiles();
390 }
391
392 /**
393 * Open the set of output files, based on the configured
394 * instance variables.
395 */
396 private void openFiles() throws IOException {
397 LogManager manager = LogManager.getLogManager();
398 manager.checkPermission();
399 if (count < 1) {
400 throw new IllegalArgumentException("file count = " + count);
401 }
402 if (limit < 0) {
403 limit = 0;
404 }
405
406 // We register our own ErrorManager during initialization
407 // so we can record exceptions.
408 InitializationErrorManager em = new InitializationErrorManager();
409 setErrorManager(em);
410
411 // Create a lock file. This grants us exclusive access
412 // to our set of output files, as long as we are alive.
413 int unique = -1;
414 for (;;) {
415 unique++;
416 if (unique > MAX_LOCKS) {
417 throw new IOException("Couldn't get lock for " + pattern);
418 }
419 // Generate a lock file name from the "unique" int.
420 lockFileName = generate(pattern, 0, unique).toString() + ".lck";
421 // Now try to lock that filename.
422 // Because some systems (e.g., Solaris) can only do file locks
423 // between processes (and not within a process), we first check
424 // if we ourself already have the file locked.
425 synchronized(locks) {
426 if (locks.get(lockFileName) != null) {
427 // We already own this lock, for a different FileHandler
428 // object. Try again.
429 continue;
430 }
431
432 try {
433 lockFileChannel = FileChannel.open(Paths.get(lockFileName),
434 CREATE_NEW, WRITE);
435 } catch (FileAlreadyExistsException ix) {
436 // try the next lock file name in the sequence
437 continue;
438 }
439
440 boolean available;
441 try {
442 available = lockFileChannel.tryLock() != null;
443 // We got the lock OK.
444 } catch (IOException ix) {
445 // We got an IOException while trying to get the lock.
446 // This normally indicates that locking is not supported
447 // on the target directory. We have to proceed without
448 // getting a lock. Drop through.
449 available = true;
450 }
451 if (available) {
452 // We got the lock. Remember it.
453 locks.put(lockFileName, lockFileName);
454 break;
455 }
456
457 // We failed to get the lock. Try next file.
458 lockFileChannel.close();
459 }
460 }
461
462 files = new File[count];
463 for (int i = 0; i < count; i++) {
464 files[i] = generate(pattern, i, unique);
465 }
466
467 // Create the initial log file.
468 if (append) {
469 open(files[0], true);
470 } else {
471 rotate();
472 }
473
474 // Did we detect any exceptions during initialization?
475 Exception ex = em.lastException;
476 if (ex != null) {
477 if (ex instanceof IOException) {
478 throw (IOException) ex;
479 } else if (ex instanceof SecurityException) {
480 throw (SecurityException) ex;
481 } else {
482 throw new IOException("Exception: " + ex);
483 }
484 }
485
486 // Install the normal default ErrorManager.
487 setErrorManager(new ErrorManager());
488 }
489
490 /**
491 * Generate a file based on a user-supplied pattern, generation number,
492 * and an integer uniqueness suffix
493 * @param pattern the pattern for naming the output file
494 * @param generation the generation number to distinguish rotated logs
495 * @param unique a unique number to resolve conflicts
496 * @return the generated File
497 * @throws IOException
498 */
499 private File generate(String pattern, int generation, int unique)
500 throws IOException {
501 File file = null;
502 String word = "";
503 int ix = 0;
504 boolean sawg = false;
505 boolean sawu = false;
506 while (ix < pattern.length()) {
507 char ch = pattern.charAt(ix);
508 ix++;
509 char ch2 = 0;
510 if (ix < pattern.length()) {
511 ch2 = Character.toLowerCase(pattern.charAt(ix));
512 }
513 if (ch == '/') {
514 if (file == null) {
515 file = new File(word);
516 } else {
517 file = new File(file, word);
518 }
519 word = "";
520 continue;
521 } else if (ch == '%') {
522 if (ch2 == 't') {
523 String tmpDir = System.getProperty("java.io.tmpdir");
524 if (tmpDir == null) {
525 tmpDir = System.getProperty("user.home");
526 }
527 file = new File(tmpDir);
528 ix++;
529 word = "";
530 continue;
531 } else if (ch2 == 'h') {
532 file = new File(System.getProperty("user.home"));
533 if (isSetUID()) {
534 // Ok, we are in a set UID program. For safety's sake
535 // we disallow attempts to open files relative to %h.
536 throw new IOException("can't use %h in set UID program");
537 }
538 ix++;
539 word = "";
540 continue;
541 } else if (ch2 == 'g') {
542 word = word + generation;
543 sawg = true;
544 ix++;
545 continue;
546 } else if (ch2 == 'u') {
547 word = word + unique;
548 sawu = true;
549 ix++;
550 continue;
551 } else if (ch2 == '%') {
552 word = word + "%";
553 ix++;
554 continue;
555 }
556 }
557 word = word + ch;
558 }
559 if (count > 1 && !sawg) {
560 word = word + "." + generation;
561 }
562 if (unique > 0 && !sawu) {
563 word = word + "." + unique;
564 }
565 if (word.length() > 0) {
566 if (file == null) {
567 file = new File(word);
568 } else {
569 file = new File(file, word);
570 }
571 }
572 return file;
573 }
574
575 /**
576 * Rotate the set of output files
577 */
578 private synchronized void rotate() {
579 Level oldLevel = getLevel();
580 setLevel(Level.OFF);
581
582 super.close();
583 for (int i = count-2; i >= 0; i--) {
584 File f1 = files[i];
585 File f2 = files[i+1];
586 if (f1.exists()) {
587 if (f2.exists()) {
588 f2.delete();
589 }
590 f1.renameTo(f2);
591 }
592 }
593 try {
594 open(files[0], false);
595 } catch (IOException ix) {
596 // We don't want to throw an exception here, but we
597 // report the exception to any registered ErrorManager.
598 reportError(null, ix, ErrorManager.OPEN_FAILURE);
599
600 }
601 setLevel(oldLevel);
602 }
603
604 /**
605 * Format and publish a <tt>LogRecord</tt>.
606 *
607 * @param record description of the log event. A null record is
608 * silently ignored and is not published
609 */
610 public synchronized void publish(LogRecord record) {
611 if (!isLoggable(record)) {
612 return;
613 }
614 super.publish(record);
615 flush();
616 if (limit > 0 && meter.written >= limit) {
617 // We performed access checks in the "init" method to make sure
618 // we are only initialized from trusted code. So we assume
619 // it is OK to write the target files, even if we are
620 // currently being called from untrusted code.
621 // So it is safe to raise privilege here.
622 AccessController.doPrivileged(new PrivilegedAction<Object>() {
623 public Object run() {
624 rotate();
625 return null;
626 }
627 });
628 }
629 }
630
631 /**
632 * Close all the files.
633 *
634 * @exception SecurityException if a security manager exists and if
635 * the caller does not have <tt>LoggingPermission("control")</tt>.
636 */
637 public synchronized void close() throws SecurityException {
638 super.close();
639 // Unlock any lock file.
640 if (lockFileName == null) {
641 return;
642 }
643 try {
644 // Close the lock file channel (which also will free any locks)
645 lockFileChannel.close();
646 } catch (Exception ex) {
647 // Problems closing the stream. Punt.
648 }
649 synchronized(locks) {
650 locks.remove(lockFileName);
651 }
652 new File(lockFileName).delete();
653 lockFileName = null;
654 lockFileChannel = null;
655 }
656
657 private static class InitializationErrorManager extends ErrorManager {
658 Exception lastException;
659 public void error(String msg, Exception ex, int code) {
660 lastException = ex;
661 }
662 }
663
664 /**
665 * check if we are in a set UID program.
666 */
667 private static native boolean isSetUID();
668 }