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 final 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 final OutputStream out;
161 int written;
162
163 MeteredStream(OutputStream out, int written) {
164 this.out = out;
165 this.written = written;
166 }
167
168 @Override
169 public void write(int b) throws IOException {
170 out.write(b);
171 written++;
172 }
173
174 @Override
175 public void write(byte buff[]) throws IOException {
176 out.write(buff);
177 written += buff.length;
178 }
179
180 @Override
181 public void write(byte buff[], int off, int len) throws IOException {
182 out.write(buff,off,len);
183 written += len;
184 }
185
186 @Override
187 public void flush() throws IOException {
188 out.flush();
189 }
190
191 @Override
192 public void close() throws IOException {
193 out.close();
194 }
195 }
196
197 private void open(File fname, boolean append) throws IOException {
198 int len = 0;
199 if (append) {
200 len = (int)fname.length();
201 }
202 FileOutputStream fout = new FileOutputStream(fname.toString(), append);
203 BufferedOutputStream bout = new BufferedOutputStream(fout);
204 meter = new MeteredStream(bout, len);
205 setOutputStream(meter);
206 }
207
208 /**
209 * Configure a FileHandler from LogManager properties and/or default values
210 * as specified in the class javadoc.
211 */
212 private void configure() {
213 LogManager manager = LogManager.getLogManager();
214
215 String cname = getClass().getName();
216
217 pattern = manager.getStringProperty(cname + ".pattern", "%h/java%u.log");
218 limit = manager.getIntProperty(cname + ".limit", 0);
219 if (limit < 0) {
220 limit = 0;
221 }
222 count = manager.getIntProperty(cname + ".count", 1);
223 if (count <= 0) {
224 count = 1;
225 }
226 append = manager.getBooleanProperty(cname + ".append", false);
227 setLevel(manager.getLevelProperty(cname + ".level", Level.ALL));
228 setFilter(manager.getFilterProperty(cname + ".filter", null));
229 setFormatter(manager.getFormatterProperty(cname + ".formatter", new XMLFormatter()));
230 try {
231 setEncoding(manager.getStringProperty(cname +".encoding", null));
232 } catch (Exception ex) {
233 try {
234 setEncoding(null);
235 } catch (Exception ex2) {
236 // doing a setEncoding with null should always work.
237 // assert false;
238 }
239 }
240 }
241
242
243 /**
244 * Construct a default <tt>FileHandler</tt>. This will be configured
245 * entirely from <tt>LogManager</tt> properties (or their default values).
246 * <p>
247 * @exception IOException if there are IO problems opening the files.
248 * @exception SecurityException if a security manager exists and if
249 * the caller does not have <tt>LoggingPermission("control"))</tt>.
250 * @exception NullPointerException if pattern property is an empty String.
251 */
252 public FileHandler() throws IOException, SecurityException {
253 checkPermission();
254 configure();
255 openFiles();
256 }
257
258 /**
259 * Initialize a <tt>FileHandler</tt> to write to the given filename.
260 * <p>
261 * The <tt>FileHandler</tt> is configured based on <tt>LogManager</tt>
262 * properties (or their default values) except that the given pattern
263 * argument is used as the filename pattern, the file limit is
264 * set to no limit, and the file count is set to one.
265 * <p>
266 * There is no limit on the amount of data that may be written,
267 * so use this with care.
268 *
269 * @param pattern the name of the output file
270 * @exception IOException if there are IO problems opening the files.
271 * @exception SecurityException if a security manager exists and if
272 * the caller does not have <tt>LoggingPermission("control")</tt>.
273 * @exception IllegalArgumentException if pattern is an empty string
274 */
275 public FileHandler(String pattern) throws IOException, SecurityException {
276 if (pattern.length() < 1 ) {
277 throw new IllegalArgumentException();
278 }
279 checkPermission();
280 configure();
281 this.pattern = pattern;
282 this.limit = 0;
283 this.count = 1;
284 openFiles();
285 }
286
287 /**
288 * Initialize a <tt>FileHandler</tt> to write to the given filename,
289 * with optional append.
290 * <p>
291 * The <tt>FileHandler</tt> is configured based on <tt>LogManager</tt>
292 * properties (or their default values) except that the given pattern
293 * argument is used as the filename pattern, the file limit is
294 * set to no limit, the file count is set to one, and the append
295 * mode is set to the given <tt>append</tt> argument.
296 * <p>
297 * There is no limit on the amount of data that may be written,
298 * so use this with care.
299 *
300 * @param pattern the name of the output file
301 * @param append specifies append mode
302 * @exception IOException if there are IO problems opening the files.
303 * @exception SecurityException if a security manager exists and if
304 * the caller does not have <tt>LoggingPermission("control")</tt>.
305 * @exception IllegalArgumentException if pattern is an empty string
306 */
307 public FileHandler(String pattern, boolean append) throws IOException,
308 SecurityException {
309 if (pattern.length() < 1 ) {
310 throw new IllegalArgumentException();
311 }
312 checkPermission();
313 configure();
314 this.pattern = pattern;
315 this.limit = 0;
316 this.count = 1;
317 this.append = append;
318 openFiles();
319 }
320
321 /**
322 * Initialize a <tt>FileHandler</tt> to write to a set of files. When
323 * (approximately) the given limit has been written to one file,
324 * another file will be opened. The output will cycle through a set
325 * of count files.
326 * <p>
327 * The <tt>FileHandler</tt> is configured based on <tt>LogManager</tt>
328 * properties (or their default values) except that the given pattern
329 * argument is used as the filename pattern, the file limit is
330 * set to the limit argument, and the file count is set to the
331 * given count argument.
332 * <p>
333 * The count must be at least 1.
334 *
335 * @param pattern the pattern for naming the output file
336 * @param limit the maximum number of bytes to write to any one file
337 * @param count the number of files to use
338 * @exception IOException if there are IO problems opening the files.
339 * @exception SecurityException if a security manager exists and if
340 * the caller does not have <tt>LoggingPermission("control")</tt>.
341 * @exception IllegalArgumentException if {@code limit < 0}, or {@code count < 1}.
342 * @exception IllegalArgumentException if pattern is an empty string
343 */
344 public FileHandler(String pattern, int limit, int count)
345 throws IOException, SecurityException {
346 if (limit < 0 || count < 1 || pattern.length() < 1) {
347 throw new IllegalArgumentException();
348 }
349 checkPermission();
350 configure();
351 this.pattern = pattern;
352 this.limit = limit;
353 this.count = count;
354 openFiles();
355 }
356
357 /**
358 * Initialize a <tt>FileHandler</tt> to write to a set of files
359 * with optional append. When (approximately) the given limit has
360 * been written to one file, another file will be opened. The
361 * output will cycle through a set of count files.
362 * <p>
363 * The <tt>FileHandler</tt> is configured based on <tt>LogManager</tt>
364 * properties (or their default values) except that the given pattern
365 * argument is used as the filename pattern, the file limit is
366 * set to the limit argument, and the file count is set to the
367 * given count argument, and the append mode is set to the given
368 * <tt>append</tt> argument.
369 * <p>
370 * The count must be at least 1.
371 *
372 * @param pattern the pattern for naming the output file
373 * @param limit the maximum number of bytes to write to any one file
374 * @param count the number of files to use
375 * @param append specifies append mode
376 * @exception IOException if there are IO problems opening the files.
377 * @exception SecurityException if a security manager exists and if
378 * the caller does not have <tt>LoggingPermission("control")</tt>.
379 * @exception IllegalArgumentException if {@code limit < 0}, or {@code count < 1}.
380 * @exception IllegalArgumentException if pattern is an empty string
381 *
382 */
383 public FileHandler(String pattern, int limit, int count, boolean append)
384 throws IOException, SecurityException {
385 if (limit < 0 || count < 1 || pattern.length() < 1) {
386 throw new IllegalArgumentException();
387 }
388 checkPermission();
389 configure();
390 this.pattern = pattern;
391 this.limit = limit;
392 this.count = count;
393 this.append = append;
394 openFiles();
395 }
396
397 /**
398 * Open the set of output files, based on the configured
399 * instance variables.
400 */
401 private void openFiles() throws IOException {
402 LogManager manager = LogManager.getLogManager();
403 manager.checkPermission();
404 if (count < 1) {
405 throw new IllegalArgumentException("file count = " + count);
406 }
407 if (limit < 0) {
408 limit = 0;
409 }
410
411 // We register our own ErrorManager during initialization
412 // so we can record exceptions.
413 InitializationErrorManager em = new InitializationErrorManager();
414 setErrorManager(em);
415
416 // Create a lock file. This grants us exclusive access
417 // to our set of output files, as long as we are alive.
418 int unique = -1;
419 for (;;) {
420 unique++;
421 if (unique > MAX_LOCKS) {
422 throw new IOException("Couldn't get lock for " + pattern);
423 }
424 // Generate a lock file name from the "unique" int.
425 lockFileName = generate(pattern, 0, unique).toString() + ".lck";
426 // Now try to lock that filename.
427 // Because some systems (e.g., Solaris) can only do file locks
428 // between processes (and not within a process), we first check
429 // if we ourself already have the file locked.
430 synchronized(locks) {
431 if (locks.get(lockFileName) != null) {
432 // We already own this lock, for a different FileHandler
433 // object. Try again.
434 continue;
435 }
436
437 try {
438 lockFileChannel = FileChannel.open(Paths.get(lockFileName),
439 CREATE_NEW, WRITE);
440 } catch (FileAlreadyExistsException ix) {
441 // try the next lock file name in the sequence
442 continue;
443 }
444
445 boolean available;
446 try {
447 available = lockFileChannel.tryLock() != null;
448 // We got the lock OK.
449 } catch (IOException ix) {
450 // We got an IOException while trying to get the lock.
451 // This normally indicates that locking is not supported
452 // on the target directory. We have to proceed without
453 // getting a lock. Drop through.
454 available = true;
455 }
456 if (available) {
457 // We got the lock. Remember it.
458 locks.put(lockFileName, lockFileName);
459 break;
460 }
461
462 // We failed to get the lock. Try next file.
463 lockFileChannel.close();
464 }
465 }
466
467 files = new File[count];
468 for (int i = 0; i < count; i++) {
469 files[i] = generate(pattern, i, unique);
470 }
471
472 // Create the initial log file.
473 if (append) {
474 open(files[0], true);
475 } else {
476 rotate();
477 }
478
479 // Did we detect any exceptions during initialization?
480 Exception ex = em.lastException;
481 if (ex != null) {
482 if (ex instanceof IOException) {
483 throw (IOException) ex;
484 } else if (ex instanceof SecurityException) {
485 throw (SecurityException) ex;
486 } else {
487 throw new IOException("Exception: " + ex);
488 }
489 }
490
491 // Install the normal default ErrorManager.
492 setErrorManager(new ErrorManager());
493 }
494
495 /**
496 * Generate a file based on a user-supplied pattern, generation number,
497 * and an integer uniqueness suffix
498 * @param pattern the pattern for naming the output file
499 * @param generation the generation number to distinguish rotated logs
500 * @param unique a unique number to resolve conflicts
501 * @return the generated File
502 * @throws IOException
503 */
504 private File generate(String pattern, int generation, int unique)
505 throws IOException {
506 File file = null;
507 String word = "";
508 int ix = 0;
509 boolean sawg = false;
510 boolean sawu = false;
511 while (ix < pattern.length()) {
512 char ch = pattern.charAt(ix);
513 ix++;
514 char ch2 = 0;
515 if (ix < pattern.length()) {
516 ch2 = Character.toLowerCase(pattern.charAt(ix));
517 }
518 if (ch == '/') {
519 if (file == null) {
520 file = new File(word);
521 } else {
522 file = new File(file, word);
523 }
524 word = "";
525 continue;
526 } else if (ch == '%') {
527 if (ch2 == 't') {
528 String tmpDir = System.getProperty("java.io.tmpdir");
529 if (tmpDir == null) {
530 tmpDir = System.getProperty("user.home");
531 }
532 file = new File(tmpDir);
533 ix++;
534 word = "";
535 continue;
536 } else if (ch2 == 'h') {
537 file = new File(System.getProperty("user.home"));
538 if (isSetUID()) {
539 // Ok, we are in a set UID program. For safety's sake
540 // we disallow attempts to open files relative to %h.
541 throw new IOException("can't use %h in set UID program");
542 }
543 ix++;
544 word = "";
545 continue;
546 } else if (ch2 == 'g') {
547 word = word + generation;
548 sawg = true;
549 ix++;
550 continue;
551 } else if (ch2 == 'u') {
552 word = word + unique;
553 sawu = true;
554 ix++;
555 continue;
556 } else if (ch2 == '%') {
557 word = word + "%";
558 ix++;
559 continue;
560 }
561 }
562 word = word + ch;
563 }
564 if (count > 1 && !sawg) {
565 word = word + "." + generation;
566 }
567 if (unique > 0 && !sawu) {
568 word = word + "." + unique;
569 }
570 if (word.length() > 0) {
571 if (file == null) {
572 file = new File(word);
573 } else {
574 file = new File(file, word);
575 }
576 }
577 return file;
578 }
579
580 /**
581 * Rotate the set of output files
582 */
583 private synchronized void rotate() {
584 Level oldLevel = getLevel();
585 setLevel(Level.OFF);
586
587 super.close();
588 for (int i = count-2; i >= 0; i--) {
589 File f1 = files[i];
590 File f2 = files[i+1];
591 if (f1.exists()) {
592 if (f2.exists()) {
593 f2.delete();
594 }
595 f1.renameTo(f2);
596 }
597 }
598 try {
599 open(files[0], false);
600 } catch (IOException ix) {
601 // We don't want to throw an exception here, but we
602 // report the exception to any registered ErrorManager.
603 reportError(null, ix, ErrorManager.OPEN_FAILURE);
604
605 }
606 setLevel(oldLevel);
607 }
608
609 /**
610 * Format and publish a <tt>LogRecord</tt>.
611 *
612 * @param record description of the log event. A null record is
613 * silently ignored and is not published
614 */
615 @Override
616 public synchronized void publish(LogRecord record) {
617 if (!isLoggable(record)) {
618 return;
619 }
620 super.publish(record);
621 flush();
622 if (limit > 0 && meter.written >= limit) {
623 // We performed access checks in the "init" method to make sure
624 // we are only initialized from trusted code. So we assume
625 // it is OK to write the target files, even if we are
626 // currently being called from untrusted code.
627 // So it is safe to raise privilege here.
628 AccessController.doPrivileged(new PrivilegedAction<Object>() {
629 @Override
630 public Object run() {
631 rotate();
632 return null;
633 }
634 });
635 }
636 }
637
638 /**
639 * Close all the files.
640 *
641 * @exception SecurityException if a security manager exists and if
642 * the caller does not have <tt>LoggingPermission("control")</tt>.
643 */
644 @Override
645 public synchronized void close() throws SecurityException {
646 super.close();
647 // Unlock any lock file.
648 if (lockFileName == null) {
649 return;
650 }
651 try {
652 // Close the lock file channel (which also will free any locks)
653 lockFileChannel.close();
654 } catch (Exception ex) {
655 // Problems closing the stream. Punt.
656 }
657 synchronized(locks) {
658 locks.remove(lockFileName);
659 }
660 new File(lockFileName).delete();
661 lockFileName = null;
662 lockFileChannel = null;
663 }
664
665 private static class InitializationErrorManager extends ErrorManager {
666 Exception lastException;
667 @Override
668 public void error(String msg, Exception ex, int code) {
669 lastException = ex;
670 }
671 }
672
673 /**
674 * check if we are in a set UID program.
675 */
676 private static native boolean isSetUID();
677 }