1 /*
2 * Copyright (c) 2000, 2013, 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.APPEND;
29 import static java.nio.file.StandardOpenOption.CREATE_NEW;
30 import static java.nio.file.StandardOpenOption.WRITE;
31
32 import java.io.BufferedOutputStream;
33 import java.io.File;
34 import java.io.FileOutputStream;
35 import java.io.IOException;
36 import java.io.OutputStream;
37 import java.nio.channels.FileChannel;
38 import java.nio.channels.OverlappingFileLockException;
39 import java.nio.file.FileAlreadyExistsException;
40 import java.nio.file.Files;
41 import java.nio.file.LinkOption;
42 import java.nio.file.NoSuchFileException;
43 import java.nio.file.Path;
44 import java.nio.file.Paths;
45 import java.security.AccessController;
46 import java.security.PrivilegedAction;
47 import java.util.HashSet;
48 import java.util.Set;
49
50 /**
51 * Simple file logging <tt>Handler</tt>.
52 * <p>
53 * The <tt>FileHandler</tt> can either write to a specified file,
54 * or it can write to a rotating set of files.
55 * <p>
56 * For a rotating set of files, as each file reaches a given size
57 * limit, it is closed, rotated out, and a new file opened.
58 * Successively older files are named by adding "0", "1", "2",
59 * etc. into the base filename.
60 * <p>
61 * By default buffering is enabled in the IO libraries but each log
62 * record is flushed out when it is complete.
63 * <p>
64 * By default the <tt>XMLFormatter</tt> class is used for formatting.
65 * <p>
66 * <b>Configuration:</b>
67 * By default each <tt>FileHandler</tt> is initialized using the following
68 * <tt>LogManager</tt> configuration properties where <tt><handler-name></tt>
69 * refers to the fully-qualified class name of the handler.
70 * If properties are not defined
71 * (or have invalid values) then the specified default values are used.
72 * <ul>
73 * <li> <handler-name>.level
74 * specifies the default level for the <tt>Handler</tt>
75 * (defaults to <tt>Level.ALL</tt>). </li>
76 * <li> <handler-name>.filter
77 * specifies the name of a <tt>Filter</tt> class to use
78 * (defaults to no <tt>Filter</tt>). </li>
79 * <li> <handler-name>.formatter
80 * specifies the name of a <tt>Formatter</tt> class to use
81 * (defaults to <tt>java.util.logging.XMLFormatter</tt>) </li>
82 * <li> <handler-name>.encoding
83 * the name of the character set encoding to use (defaults to
84 * the default platform encoding). </li>
85 * <li> <handler-name>.limit
86 * specifies an approximate maximum amount to write (in bytes)
87 * to any one file. If this is zero, then there is no limit.
88 * (Defaults to no limit). </li>
89 * <li> <handler-name>.count
90 * specifies how many output files to cycle through (defaults to 1). </li>
91 * <li> <handler-name>.pattern
92 * specifies a pattern for generating the output file name. See
93 * below for details. (Defaults to "%h/java%u.log"). </li>
94 * <li> <handler-name>.append
95 * specifies whether the FileHandler should append onto
96 * any existing files (defaults to false). </li>
97 * </ul>
98 * <p>
99 * For example, the properties for {@code FileHandler} would be:
100 * <ul>
101 * <li> java.util.logging.FileHandler.level=INFO </li>
102 * <li> java.util.logging.FileHandler.formatter=java.util.logging.SimpleFormatter </li>
103 * </ul>
104 * <p>
105 * For a custom handler, e.g. com.foo.MyHandler, the properties would be:
106 * <ul>
107 * <li> com.foo.MyHandler.level=INFO </li>
108 * <li> com.foo.MyHandler.formatter=java.util.logging.SimpleFormatter </li>
109 * </ul>
110 * <p>
111 * A pattern consists of a string that includes the following special
112 * components that will be replaced at runtime:
113 * <ul>
114 * <li> "/" the local pathname separator </li>
115 * <li> "%t" the system temporary directory </li>
116 * <li> "%h" the value of the "user.home" system property </li>
117 * <li> "%g" the generation number to distinguish rotated logs </li>
118 * <li> "%u" a unique number to resolve conflicts </li>
119 * <li> "%%" translates to a single percent sign "%" </li>
120 * </ul>
121 * If no "%g" field has been specified and the file count is greater
122 * than one, then the generation number will be added to the end of
123 * the generated filename, after a dot.
124 * <p>
125 * Thus for example a pattern of "%t/java%g.log" with a count of 2
126 * would typically cause log files to be written on Solaris to
127 * /var/tmp/java0.log and /var/tmp/java1.log whereas on Windows 95 they
128 * would be typically written to C:\TEMP\java0.log and C:\TEMP\java1.log
129 * <p>
130 * Generation numbers follow the sequence 0, 1, 2, etc.
131 * <p>
132 * Normally the "%u" unique field is set to 0. However, if the <tt>FileHandler</tt>
133 * tries to open the filename and finds the file is currently in use by
134 * another process it will increment the unique number field and try
135 * again. This will be repeated until <tt>FileHandler</tt> finds a file name that
136 * is not currently in use. If there is a conflict and no "%u" field has
137 * been specified, it will be added at the end of the filename after a dot.
138 * (This will be after any automatically added generation number.)
139 * <p>
140 * Thus if three processes were all trying to log to fred%u.%g.txt then
141 * they might end up using fred0.0.txt, fred1.0.txt, fred2.0.txt as
142 * the first file in their rotating sequences.
143 * <p>
144 * Note that the use of unique ids to avoid conflicts is only guaranteed
145 * to work reliably when using a local disk file system.
146 *
147 * @since 1.4
148 */
149
150 public class FileHandler extends StreamHandler {
151 private MeteredStream meter;
152 private boolean append;
153 private int limit; // zero => no limit.
154 private int count;
155 private String pattern;
156 private String lockFileName;
157 private FileChannel lockFileChannel;
158 private File files[];
159 private static final int MAX_LOCKS = 100;
160 private static final Set<String> locks = new HashSet<>();
161
162 /**
163 * A metered stream is a subclass of OutputStream that
164 * (a) forwards all its output to a target stream
165 * (b) keeps track of how many bytes have been written
166 */
167 private class MeteredStream extends OutputStream {
168 final OutputStream out;
169 int written;
170
171 MeteredStream(OutputStream out, int written) {
172 this.out = out;
173 this.written = written;
174 }
175
176 @Override
177 public void write(int b) throws IOException {
178 out.write(b);
179 written++;
180 }
181
182 @Override
183 public void write(byte buff[]) throws IOException {
184 out.write(buff);
185 written += buff.length;
186 }
187
188 @Override
189 public void write(byte buff[], int off, int len) throws IOException {
190 out.write(buff,off,len);
191 written += len;
192 }
193
194 @Override
195 public void flush() throws IOException {
196 out.flush();
197 }
198
199 @Override
200 public void close() throws IOException {
201 out.close();
202 }
203 }
204
205 private void open(File fname, boolean append) throws IOException {
206 int len = 0;
207 if (append) {
208 len = (int)fname.length();
209 }
210 FileOutputStream fout = new FileOutputStream(fname.toString(), append);
211 BufferedOutputStream bout = new BufferedOutputStream(fout);
212 meter = new MeteredStream(bout, len);
213 setOutputStream(meter);
214 }
215
216 /**
217 * Configure a FileHandler from LogManager properties and/or default values
218 * as specified in the class javadoc.
219 */
220 private void configure() {
221 LogManager manager = LogManager.getLogManager();
222
223 String cname = getClass().getName();
224
225 pattern = manager.getStringProperty(cname + ".pattern", "%h/java%u.log");
226 limit = manager.getIntProperty(cname + ".limit", 0);
227 if (limit < 0) {
228 limit = 0;
229 }
230 count = manager.getIntProperty(cname + ".count", 1);
231 if (count <= 0) {
232 count = 1;
233 }
234 append = manager.getBooleanProperty(cname + ".append", false);
235 setLevel(manager.getLevelProperty(cname + ".level", Level.ALL));
236 setFilter(manager.getFilterProperty(cname + ".filter", null));
237 setFormatter(manager.getFormatterProperty(cname + ".formatter", new XMLFormatter()));
238 try {
239 setEncoding(manager.getStringProperty(cname +".encoding", null));
240 } catch (Exception ex) {
241 try {
242 setEncoding(null);
243 } catch (Exception ex2) {
244 // doing a setEncoding with null should always work.
245 // assert false;
246 }
247 }
248 }
249
250
251 /**
252 * Construct a default <tt>FileHandler</tt>. This will be configured
253 * entirely from <tt>LogManager</tt> properties (or their default values).
254 *
255 * @exception IOException if there are IO problems opening the files.
256 * @exception SecurityException if a security manager exists and if
257 * the caller does not have <tt>LoggingPermission("control"))</tt>.
258 * @exception NullPointerException if pattern property is an empty String.
259 */
260 public FileHandler() throws IOException, SecurityException {
261 checkPermission();
262 configure();
263 openFiles();
264 }
265
266 /**
267 * Initialize a <tt>FileHandler</tt> to write to the given filename.
268 * <p>
269 * The <tt>FileHandler</tt> is configured based on <tt>LogManager</tt>
270 * properties (or their default values) except that the given pattern
271 * argument is used as the filename pattern, the file limit is
272 * set to no limit, and the file count is set to one.
273 * <p>
274 * There is no limit on the amount of data that may be written,
275 * so use this with care.
276 *
277 * @param pattern the name of the output file
278 * @exception IOException if there are IO problems opening the files.
279 * @exception SecurityException if a security manager exists and if
280 * the caller does not have <tt>LoggingPermission("control")</tt>.
281 * @exception IllegalArgumentException if pattern is an empty string
282 */
283 public FileHandler(String pattern) throws IOException, SecurityException {
284 if (pattern.length() < 1 ) {
285 throw new IllegalArgumentException();
286 }
287 checkPermission();
288 configure();
289 this.pattern = pattern;
290 this.limit = 0;
291 this.count = 1;
292 openFiles();
293 }
294
295 /**
296 * Initialize a <tt>FileHandler</tt> to write to the given filename,
297 * with optional append.
298 * <p>
299 * The <tt>FileHandler</tt> is configured based on <tt>LogManager</tt>
300 * properties (or their default values) except that the given pattern
301 * argument is used as the filename pattern, the file limit is
302 * set to no limit, the file count is set to one, and the append
303 * mode is set to the given <tt>append</tt> argument.
304 * <p>
305 * There is no limit on the amount of data that may be written,
306 * so use this with care.
307 *
308 * @param pattern the name of the output file
309 * @param append specifies append mode
310 * @exception IOException if there are IO problems opening the files.
311 * @exception SecurityException if a security manager exists and if
312 * the caller does not have <tt>LoggingPermission("control")</tt>.
313 * @exception IllegalArgumentException if pattern is an empty string
314 */
315 public FileHandler(String pattern, boolean append) throws IOException,
316 SecurityException {
317 if (pattern.length() < 1 ) {
318 throw new IllegalArgumentException();
319 }
320 checkPermission();
321 configure();
322 this.pattern = pattern;
323 this.limit = 0;
324 this.count = 1;
325 this.append = append;
326 openFiles();
327 }
328
329 /**
330 * Initialize a <tt>FileHandler</tt> to write to a set of files. When
331 * (approximately) the given limit has been written to one file,
332 * another file will be opened. The output will cycle through a set
333 * of count files.
334 * <p>
335 * The <tt>FileHandler</tt> is configured based on <tt>LogManager</tt>
336 * properties (or their default values) except that the given pattern
337 * argument is used as the filename pattern, the file limit is
338 * set to the limit argument, and the file count is set to the
339 * given count argument.
340 * <p>
341 * The count must be at least 1.
342 *
343 * @param pattern the pattern for naming the output file
344 * @param limit the maximum number of bytes to write to any one file
345 * @param count the number of files to use
346 * @exception IOException if there are IO problems opening the files.
347 * @exception SecurityException if a security manager exists and if
348 * the caller does not have <tt>LoggingPermission("control")</tt>.
349 * @exception IllegalArgumentException if {@code limit < 0}, or {@code count < 1}.
350 * @exception IllegalArgumentException if pattern is an empty string
351 */
352 public FileHandler(String pattern, int limit, int count)
353 throws IOException, SecurityException {
354 if (limit < 0 || count < 1 || pattern.length() < 1) {
355 throw new IllegalArgumentException();
356 }
357 checkPermission();
358 configure();
359 this.pattern = pattern;
360 this.limit = limit;
361 this.count = count;
362 openFiles();
363 }
364
365 /**
366 * Initialize a <tt>FileHandler</tt> to write to a set of files
367 * with optional append. When (approximately) the given limit has
368 * been written to one file, another file will be opened. The
369 * output will cycle through a set of count files.
370 * <p>
371 * The <tt>FileHandler</tt> is configured based on <tt>LogManager</tt>
372 * properties (or their default values) except that the given pattern
373 * argument is used as the filename pattern, the file limit is
374 * set to the limit argument, and the file count is set to the
375 * given count argument, and the append mode is set to the given
376 * <tt>append</tt> argument.
377 * <p>
378 * The count must be at least 1.
379 *
380 * @param pattern the pattern for naming the output file
381 * @param limit the maximum number of bytes to write to any one file
382 * @param count the number of files to use
383 * @param append specifies append mode
384 * @exception IOException if there are IO problems opening the files.
385 * @exception SecurityException if a security manager exists and if
386 * the caller does not have <tt>LoggingPermission("control")</tt>.
387 * @exception IllegalArgumentException if {@code limit < 0}, or {@code count < 1}.
388 * @exception IllegalArgumentException if pattern is an empty string
389 *
390 */
391 public FileHandler(String pattern, int limit, int count, boolean append)
392 throws IOException, SecurityException {
393 if (limit < 0 || count < 1 || pattern.length() < 1) {
394 throw new IllegalArgumentException();
395 }
396 checkPermission();
397 configure();
398 this.pattern = pattern;
399 this.limit = limit;
400 this.count = count;
401 this.append = append;
402 openFiles();
403 }
404
405 private boolean isParentWritable(Path path) {
406 Path parent = path.getParent();
407 if (parent == null) {
408 parent = path.toAbsolutePath().getParent();
409 }
410 return parent != null && Files.isWritable(parent);
411 }
412
413 /**
414 * Open the set of output files, based on the configured
415 * instance variables.
416 */
417 private void openFiles() throws IOException {
418 LogManager manager = LogManager.getLogManager();
419 manager.checkPermission();
420 if (count < 1) {
421 throw new IllegalArgumentException("file count = " + count);
422 }
423 if (limit < 0) {
424 limit = 0;
425 }
426
427 // We register our own ErrorManager during initialization
428 // so we can record exceptions.
429 InitializationErrorManager em = new InitializationErrorManager();
430 setErrorManager(em);
431
432 // Create a lock file. This grants us exclusive access
433 // to our set of output files, as long as we are alive.
434 int unique = -1;
435 for (;;) {
436 unique++;
437 if (unique > MAX_LOCKS) {
438 throw new IOException("Couldn't get lock for " + pattern);
439 }
440 // Generate a lock file name from the "unique" int.
441 lockFileName = generate(pattern, 0, unique).toString() + ".lck";
442 // Now try to lock that filename.
443 // Because some systems (e.g., Solaris) can only do file locks
444 // between processes (and not within a process), we first check
445 // if we ourself already have the file locked.
446 synchronized(locks) {
447 if (locks.contains(lockFileName)) {
448 // We already own this lock, for a different FileHandler
449 // object. Try again.
450 continue;
451 }
452
453 final Path lockFilePath = Paths.get(lockFileName);
454 FileChannel channel = null;
455 int retries = -1;
456 boolean fileCreated = false;
457 while (channel == null && retries++ < 1) {
458 try {
459 channel = FileChannel.open(lockFilePath,
460 CREATE_NEW, WRITE);
461 fileCreated = true;
462 } catch (FileAlreadyExistsException ix) {
463 // This may be a zombie file left over by a previous
464 // execution. Reuse it - but only if we can actually
465 // write to its directory.
466 // Note that this is a situation that may happen,
467 // but not too frequently.
468 if (Files.isRegularFile(lockFilePath, LinkOption.NOFOLLOW_LINKS)
469 && isParentWritable(lockFilePath)) {
470 try {
471 channel = FileChannel.open(lockFilePath,
472 WRITE, APPEND);
473 } catch (NoSuchFileException x) {
474 // Race condition - retry once, and if that
475 // fails again just try the next name in
476 // the sequence.
477 continue;
478 } catch(IOException x) {
479 // the file may not be writable for us.
480 // try the next name in the sequence
481 break;
482 }
483 } else {
484 // at this point channel should still be null.
485 // break and try the next name in the sequence.
486 break;
487 }
488 }
489 }
490
491 if (channel == null) continue; // try the next name;
492 lockFileChannel = channel;
493
494 boolean available;
495 try {
496 available = lockFileChannel.tryLock() != null;
497 // We got the lock OK.
498 // At this point we could call File.deleteOnExit().
499 // However, this could have undesirable side effects
500 // as indicated by JDK-4872014. So we will instead
501 // rely on the fact that close() will remove the lock
502 // file and that whoever is creating FileHandlers should
503 // be responsible for closing them.
504 } catch (IOException ix) {
505 // We got an IOException while trying to get the lock.
506 // This normally indicates that locking is not supported
507 // on the target directory. We have to proceed without
508 // getting a lock. Drop through, but only if we did
509 // create the file...
510 available = fileCreated;
511 } catch (OverlappingFileLockException x) {
512 // someone already locked this file in this VM, through
513 // some other channel - that is - using something else
514 // than new FileHandler(...);
515 // continue searching for an available lock.
516 available = false;
517 }
518 if (available) {
519 // We got the lock. Remember it.
520 locks.add(lockFileName);
521 break;
522 }
523
524 // We failed to get the lock. Try next file.
525 lockFileChannel.close();
526 }
527 }
528
529 files = new File[count];
530 for (int i = 0; i < count; i++) {
531 files[i] = generate(pattern, i, unique);
532 }
533
534 // Create the initial log file.
535 if (append) {
536 open(files[0], true);
537 } else {
538 rotate();
539 }
540
541 // Did we detect any exceptions during initialization?
542 Exception ex = em.lastException;
543 if (ex != null) {
544 if (ex instanceof IOException) {
545 throw (IOException) ex;
546 } else if (ex instanceof SecurityException) {
547 throw (SecurityException) ex;
548 } else {
549 throw new IOException("Exception: " + ex);
550 }
551 }
552
553 // Install the normal default ErrorManager.
554 setErrorManager(new ErrorManager());
555 }
556
557 /**
558 * Generate a file based on a user-supplied pattern, generation number,
559 * and an integer uniqueness suffix
560 * @param pattern the pattern for naming the output file
561 * @param generation the generation number to distinguish rotated logs
562 * @param unique a unique number to resolve conflicts
563 * @return the generated File
564 * @throws IOException
565 */
566 private File generate(String pattern, int generation, int unique)
567 throws IOException {
568 File file = null;
569 String word = "";
570 int ix = 0;
571 boolean sawg = false;
572 boolean sawu = false;
573 while (ix < pattern.length()) {
574 char ch = pattern.charAt(ix);
575 ix++;
576 char ch2 = 0;
577 if (ix < pattern.length()) {
578 ch2 = Character.toLowerCase(pattern.charAt(ix));
579 }
580 if (ch == '/') {
581 if (file == null) {
582 file = new File(word);
583 } else {
584 file = new File(file, word);
585 }
586 word = "";
587 continue;
588 } else if (ch == '%') {
589 if (ch2 == 't') {
590 String tmpDir = System.getProperty("java.io.tmpdir");
591 if (tmpDir == null) {
592 tmpDir = System.getProperty("user.home");
593 }
594 file = new File(tmpDir);
595 ix++;
596 word = "";
597 continue;
598 } else if (ch2 == 'h') {
599 file = new File(System.getProperty("user.home"));
600 if (sun.misc.VM.isSetUID()) {
601 // Ok, we are in a set UID program. For safety's sake
602 // we disallow attempts to open files relative to %h.
603 throw new IOException("can't use %h in set UID program");
604 }
605 ix++;
606 word = "";
607 continue;
608 } else if (ch2 == 'g') {
609 word = word + generation;
610 sawg = true;
611 ix++;
612 continue;
613 } else if (ch2 == 'u') {
614 word = word + unique;
615 sawu = true;
616 ix++;
617 continue;
618 } else if (ch2 == '%') {
619 word = word + "%";
620 ix++;
621 continue;
622 }
623 }
624 word = word + ch;
625 }
626 if (count > 1 && !sawg) {
627 word = word + "." + generation;
628 }
629 if (unique > 0 && !sawu) {
630 word = word + "." + unique;
631 }
632 if (word.length() > 0) {
633 if (file == null) {
634 file = new File(word);
635 } else {
636 file = new File(file, word);
637 }
638 }
639 return file;
640 }
641
642 /**
643 * Rotate the set of output files
644 */
645 private synchronized void rotate() {
646 Level oldLevel = getLevel();
647 setLevel(Level.OFF);
648
649 super.close();
650 for (int i = count-2; i >= 0; i--) {
651 File f1 = files[i];
652 File f2 = files[i+1];
653 if (f1.exists()) {
654 if (f2.exists()) {
655 f2.delete();
656 }
657 f1.renameTo(f2);
658 }
659 }
660 try {
661 open(files[0], false);
662 } catch (IOException ix) {
663 // We don't want to throw an exception here, but we
664 // report the exception to any registered ErrorManager.
665 reportError(null, ix, ErrorManager.OPEN_FAILURE);
666
667 }
668 setLevel(oldLevel);
669 }
670
671 /**
672 * Format and publish a <tt>LogRecord</tt>.
673 *
674 * @param record description of the log event. A null record is
675 * silently ignored and is not published
676 */
677 @Override
678 public synchronized void publish(LogRecord record) {
679 if (!isLoggable(record)) {
680 return;
681 }
682 super.publish(record);
683 flush();
684 if (limit > 0 && meter.written >= limit) {
685 // We performed access checks in the "init" method to make sure
686 // we are only initialized from trusted code. So we assume
687 // it is OK to write the target files, even if we are
688 // currently being called from untrusted code.
689 // So it is safe to raise privilege here.
690 AccessController.doPrivileged(new PrivilegedAction<Object>() {
691 @Override
692 public Object run() {
693 rotate();
694 return null;
695 }
696 });
697 }
698 }
699
700 /**
701 * Close all the files.
702 *
703 * @exception SecurityException if a security manager exists and if
704 * the caller does not have <tt>LoggingPermission("control")</tt>.
705 */
706 @Override
707 public synchronized void close() throws SecurityException {
708 super.close();
709 // Unlock any lock file.
710 if (lockFileName == null) {
711 return;
712 }
713 try {
714 // Close the lock file channel (which also will free any locks)
715 lockFileChannel.close();
716 } catch (Exception ex) {
717 // Problems closing the stream. Punt.
718 }
719 synchronized(locks) {
720 locks.remove(lockFileName);
721 }
722 new File(lockFileName).delete();
723 lockFileName = null;
724 lockFileChannel = null;
725 }
726
727 private static class InitializationErrorManager extends ErrorManager {
728 Exception lastException;
729 @Override
730 public void error(String msg, Exception ex, int code) {
731 lastException = ex;
732 }
733 }
734 }