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 }