FileHandler.java revision 2c87ad3a45cecf9e344487cad1abfdebe79f2c7c
1/* 2 * Copyright (C) 2014 The Android Open Source Project 3 * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved. 4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 5 * 6 * This code is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License version 2 only, as 8 * published by the Free Software Foundation. Oracle designates this 9 * particular file as subject to the "Classpath" exception as provided 10 * by Oracle in the LICENSE file that accompanied this code. 11 * 12 * This code is distributed in the hope that it will be useful, but WITHOUT 13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 15 * version 2 for more details (a copy is included in the LICENSE file that 16 * accompanied this code). 17 * 18 * You should have received a copy of the GNU General Public License version 19 * 2 along with this work; if not, write to the Free Software Foundation, 20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 21 * 22 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 23 * or visit www.oracle.com if you need additional information or have any 24 * questions. 25 */ 26 27package java.util.logging; 28 29import java.io.*; 30import java.nio.channels.FileChannel; 31import java.nio.channels.FileLock; 32import java.security.*; 33 34/** 35 * Simple file logging <tt>Handler</tt>. 36 * <p> 37 * The <tt>FileHandler</tt> can either write to a specified file, 38 * or it can write to a rotating set of files. 39 * <p> 40 * For a rotating set of files, as each file reaches a given size 41 * limit, it is closed, rotated out, and a new file opened. 42 * Successively older files are named by adding "0", "1", "2", 43 * etc. into the base filename. 44 * <p> 45 * By default buffering is enabled in the IO libraries but each log 46 * record is flushed out when it is complete. 47 * <p> 48 * By default the <tt>XMLFormatter</tt> class is used for formatting. 49 * <p> 50 * <b>Configuration:</b> 51 * By default each <tt>FileHandler</tt> is initialized using the following 52 * <tt>LogManager</tt> configuration properties. If properties are not defined 53 * (or have invalid values) then the specified default values are used. 54 * <ul> 55 * <li> java.util.logging.FileHandler.level 56 * specifies the default level for the <tt>Handler</tt> 57 * (defaults to <tt>Level.ALL</tt>). 58 * <li> java.util.logging.FileHandler.filter 59 * specifies the name of a <tt>Filter</tt> class to use 60 * (defaults to no <tt>Filter</tt>). 61 * <li> java.util.logging.FileHandler.formatter 62 * specifies the name of a <tt>Formatter</tt> class to use 63 * (defaults to <tt>java.util.logging.XMLFormatter</tt>) 64 * <li> java.util.logging.FileHandler.encoding 65 * the name of the character set encoding to use (defaults to 66 * the default platform encoding). 67 * <li> java.util.logging.FileHandler.limit 68 * specifies an approximate maximum amount to write (in bytes) 69 * to any one file. If this is zero, then there is no limit. 70 * (Defaults to no limit). 71 * <li> java.util.logging.FileHandler.count 72 * specifies how many output files to cycle through (defaults to 1). 73 * <li> java.util.logging.FileHandler.pattern 74 * specifies a pattern for generating the output file name. See 75 * below for details. (Defaults to "%h/java%u.log"). 76 * <li> java.util.logging.FileHandler.append 77 * specifies whether the FileHandler should append onto 78 * any existing files (defaults to false). 79 * </ul> 80 * <p> 81 * <p> 82 * A pattern consists of a string that includes the following special 83 * components that will be replaced at runtime: 84 * <ul> 85 * <li> "/" the local pathname separator 86 * <li> "%t" the system temporary directory 87 * <li> "%h" the value of the "user.home" system property 88 * <li> "%g" the generation number to distinguish rotated logs 89 * <li> "%u" a unique number to resolve conflicts 90 * <li> "%%" translates to a single percent sign "%" 91 * </ul> 92 * If no "%g" field has been specified and the file count is greater 93 * than one, then the generation number will be added to the end of 94 * the generated filename, after a dot. 95 * <p> 96 * Thus for example a pattern of "%t/java%g.log" with a count of 2 97 * would typically cause log files to be written on Solaris to 98 * /var/tmp/java0.log and /var/tmp/java1.log whereas on Windows 95 they 99 * would be typically written to C:\TEMP\java0.log and C:\TEMP\java1.log 100 * <p> 101 * Generation numbers follow the sequence 0, 1, 2, etc. 102 * <p> 103 * Normally the "%u" unique field is set to 0. However, if the <tt>FileHandler</tt> 104 * tries to open the filename and finds the file is currently in use by 105 * another process it will increment the unique number field and try 106 * again. This will be repeated until <tt>FileHandler</tt> finds a file name that 107 * is not currently in use. If there is a conflict and no "%u" field has 108 * been specified, it will be added at the end of the filename after a dot. 109 * (This will be after any automatically added generation number.) 110 * <p> 111 * Thus if three processes were all trying to log to fred%u.%g.txt then 112 * they might end up using fred0.0.txt, fred1.0.txt, fred2.0.txt as 113 * the first file in their rotating sequences. 114 * <p> 115 * Note that the use of unique ids to avoid conflicts is only guaranteed 116 * to work reliably when using a local disk file system. 117 * 118 * @since 1.4 119 */ 120 121public class FileHandler extends StreamHandler { 122 private MeteredStream meter; 123 private boolean append; 124 private int limit; // zero => no limit. 125 private int count; 126 private String pattern; 127 private String lockFileName; 128 private FileOutputStream lockStream; 129 private File files[]; 130 private static final int MAX_LOCKS = 100; 131 private static java.util.HashMap<String, String> locks = new java.util.HashMap<>(); 132 133 // A metered stream is a subclass of OutputStream that 134 // (a) forwards all its output to a target stream 135 // (b) keeps track of how many bytes have been written 136 private class MeteredStream extends OutputStream { 137 OutputStream out; 138 int written; 139 140 MeteredStream(OutputStream out, int written) { 141 this.out = out; 142 this.written = written; 143 } 144 145 public void write(int b) throws IOException { 146 out.write(b); 147 written++; 148 } 149 150 public void write(byte buff[]) throws IOException { 151 out.write(buff); 152 written += buff.length; 153 } 154 155 public void write(byte buff[], int off, int len) throws IOException { 156 out.write(buff,off,len); 157 written += len; 158 } 159 160 public void flush() throws IOException { 161 out.flush(); 162 } 163 164 public void close() throws IOException { 165 out.close(); 166 } 167 } 168 169 private void open(File fname, boolean append) throws IOException { 170 int len = 0; 171 if (append) { 172 len = (int)fname.length(); 173 } 174 FileOutputStream fout = new FileOutputStream(fname.toString(), append); 175 BufferedOutputStream bout = new BufferedOutputStream(fout); 176 meter = new MeteredStream(bout, len); 177 setOutputStream(meter); 178 } 179 180 // Private method to configure a FileHandler from LogManager 181 // properties and/or default values as specified in the class 182 // javadoc. 183 private void configure() { 184 LogManager manager = LogManager.getLogManager(); 185 186 String cname = getClass().getName(); 187 188 pattern = manager.getStringProperty(cname + ".pattern", "%h/java%u.log"); 189 limit = manager.getIntProperty(cname + ".limit", 0); 190 if (limit < 0) { 191 limit = 0; 192 } 193 count = manager.getIntProperty(cname + ".count", 1); 194 if (count <= 0) { 195 count = 1; 196 } 197 append = manager.getBooleanProperty(cname + ".append", false); 198 setLevel(manager.getLevelProperty(cname + ".level", Level.ALL)); 199 setFilter(manager.getFilterProperty(cname + ".filter", null)); 200 setFormatter(manager.getFormatterProperty(cname + ".formatter", new XMLFormatter())); 201 try { 202 setEncoding(manager.getStringProperty(cname +".encoding", null)); 203 } catch (Exception ex) { 204 try { 205 setEncoding(null); 206 } catch (Exception ex2) { 207 // doing a setEncoding with null should always work. 208 // assert false; 209 } 210 } 211 } 212 213 214 /** 215 * Construct a default <tt>FileHandler</tt>. This will be configured 216 * entirely from <tt>LogManager</tt> properties (or their default values). 217 * <p> 218 * @exception IOException if there are IO problems opening the files. 219 * @exception SecurityException if a security manager exists and if 220 * the caller does not have <tt>LoggingPermission("control"))</tt>. 221 * @exception NullPointerException if pattern property is an empty String. 222 */ 223 public FileHandler() throws IOException, SecurityException { 224 checkPermission(); 225 configure(); 226 openFiles(); 227 } 228 229 /** 230 * Initialize a <tt>FileHandler</tt> to write to the given filename. 231 * <p> 232 * The <tt>FileHandler</tt> is configured based on <tt>LogManager</tt> 233 * properties (or their default values) except that the given pattern 234 * argument is used as the filename pattern, the file limit is 235 * set to no limit, and the file count is set to one. 236 * <p> 237 * There is no limit on the amount of data that may be written, 238 * so use this with care. 239 * 240 * @param pattern the name of the output file 241 * @exception IOException if there are IO problems opening the files. 242 * @exception SecurityException if a security manager exists and if 243 * the caller does not have <tt>LoggingPermission("control")</tt>. 244 * @exception IllegalArgumentException if pattern is an empty string 245 */ 246 public FileHandler(String pattern) throws IOException, SecurityException { 247 if (pattern.length() < 1 ) { 248 throw new IllegalArgumentException(); 249 } 250 checkPermission(); 251 configure(); 252 this.pattern = pattern; 253 this.limit = 0; 254 this.count = 1; 255 openFiles(); 256 } 257 258 /** 259 * Initialize a <tt>FileHandler</tt> to write to the given filename, 260 * with optional append. 261 * <p> 262 * The <tt>FileHandler</tt> is configured based on <tt>LogManager</tt> 263 * properties (or their default values) except that the given pattern 264 * argument is used as the filename pattern, the file limit is 265 * set to no limit, the file count is set to one, and the append 266 * mode is set to the given <tt>append</tt> argument. 267 * <p> 268 * There is no limit on the amount of data that may be written, 269 * so use this with care. 270 * 271 * @param pattern the name of the output file 272 * @param append specifies append mode 273 * @exception IOException if there are IO problems opening the files. 274 * @exception SecurityException if a security manager exists and if 275 * the caller does not have <tt>LoggingPermission("control")</tt>. 276 * @exception IllegalArgumentException if pattern is an empty string 277 */ 278 public FileHandler(String pattern, boolean append) throws IOException, SecurityException { 279 if (pattern.length() < 1 ) { 280 throw new IllegalArgumentException(); 281 } 282 checkPermission(); 283 configure(); 284 this.pattern = pattern; 285 this.limit = 0; 286 this.count = 1; 287 this.append = append; 288 openFiles(); 289 } 290 291 /** 292 * Initialize a <tt>FileHandler</tt> to write to a set of files. When 293 * (approximately) the given limit has been written to one file, 294 * another file will be opened. The output will cycle through a set 295 * of count files. 296 * <p> 297 * The <tt>FileHandler</tt> is configured based on <tt>LogManager</tt> 298 * properties (or their default values) except that the given pattern 299 * argument is used as the filename pattern, the file limit is 300 * set to the limit argument, and the file count is set to the 301 * given count argument. 302 * <p> 303 * The count must be at least 1. 304 * 305 * @param pattern the pattern for naming the output file 306 * @param limit the maximum number of bytes to write to any one file 307 * @param count the number of files to use 308 * @exception IOException if there are IO problems opening the files. 309 * @exception SecurityException if a security manager exists and if 310 * the caller does not have <tt>LoggingPermission("control")</tt>. 311 * @exception IllegalArgumentException if limit < 0, or count < 1. 312 * @exception IllegalArgumentException if pattern is an empty string 313 */ 314 public FileHandler(String pattern, int limit, int count) 315 throws IOException, SecurityException { 316 if (limit < 0 || count < 1 || pattern.length() < 1) { 317 throw new IllegalArgumentException(); 318 } 319 checkPermission(); 320 configure(); 321 this.pattern = pattern; 322 this.limit = limit; 323 this.count = count; 324 openFiles(); 325 } 326 327 /** 328 * Initialize a <tt>FileHandler</tt> to write to a set of files 329 * with optional append. When (approximately) the given limit has 330 * been written to one file, another file will be opened. The 331 * output will cycle through a set of count files. 332 * <p> 333 * The <tt>FileHandler</tt> is configured based on <tt>LogManager</tt> 334 * properties (or their default values) except that the given pattern 335 * argument is used as the filename pattern, the file limit is 336 * set to the limit argument, and the file count is set to the 337 * given count argument, and the append mode is set to the given 338 * <tt>append</tt> argument. 339 * <p> 340 * The count must be at least 1. 341 * 342 * @param pattern the pattern for naming the output file 343 * @param limit the maximum number of bytes to write to any one file 344 * @param count the number of files to use 345 * @param append specifies append mode 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 limit < 0, or count < 1. 350 * @exception IllegalArgumentException if pattern is an empty string 351 * 352 */ 353 public FileHandler(String pattern, int limit, int count, boolean append) 354 throws IOException, SecurityException { 355 if (limit < 0 || count < 1 || pattern.length() < 1) { 356 throw new IllegalArgumentException(); 357 } 358 checkPermission(); 359 configure(); 360 this.pattern = pattern; 361 this.limit = limit; 362 this.count = count; 363 this.append = append; 364 openFiles(); 365 } 366 367 // Private method to open the set of output files, based on the 368 // configured instance variables. 369 private void openFiles() throws IOException { 370 LogManager manager = LogManager.getLogManager(); 371 manager.checkPermission(); 372 if (count < 1) { 373 throw new IllegalArgumentException("file count = " + count); 374 } 375 if (limit < 0) { 376 limit = 0; 377 } 378 379 // We register our own ErrorManager during initialization 380 // so we can record exceptions. 381 InitializationErrorManager em = new InitializationErrorManager(); 382 setErrorManager(em); 383 384 // Create a lock file. This grants us exclusive access 385 // to our set of output files, as long as we are alive. 386 int unique = -1; 387 for (;;) { 388 unique++; 389 if (unique > MAX_LOCKS) { 390 throw new IOException("Couldn't get lock for " + pattern); 391 } 392 // Generate a lock file name from the "unique" int. 393 lockFileName = generate(pattern, 0, unique).toString() + ".lck"; 394 // Now try to lock that filename. 395 // Because some systems (e.g., Solaris) can only do file locks 396 // between processes (and not within a process), we first check 397 // if we ourself already have the file locked. 398 synchronized(locks) { 399 if (locks.get(lockFileName) != null) { 400 // We already own this lock, for a different FileHandler 401 // object. Try again. 402 continue; 403 } 404 FileChannel fc; 405 try { 406 lockStream = new FileOutputStream(lockFileName); 407 fc = lockStream.getChannel(); 408 } catch (IOException ix) { 409 // We got an IOException while trying to open the file. 410 // Try the next file. 411 continue; 412 } 413 boolean available; 414 try { 415 available = fc.tryLock() != null; 416 // We got the lock OK. 417 } catch (IOException ix) { 418 // We got an IOException while trying to get the lock. 419 // This normally indicates that locking is not supported 420 // on the target directory. We have to proceed without 421 // getting a lock. Drop through. 422 available = true; 423 } 424 if (available) { 425 // We got the lock. Remember it. 426 locks.put(lockFileName, lockFileName); 427 break; 428 } 429 430 // We failed to get the lock. Try next file. 431 fc.close(); 432 } 433 } 434 435 files = new File[count]; 436 for (int i = 0; i < count; i++) { 437 files[i] = generate(pattern, i, unique); 438 } 439 440 // Create the initial log file. 441 if (append) { 442 open(files[0], true); 443 } else { 444 rotate(); 445 } 446 447 // Did we detect any exceptions during initialization? 448 Exception ex = em.lastException; 449 if (ex != null) { 450 if (ex instanceof IOException) { 451 throw (IOException) ex; 452 } else if (ex instanceof SecurityException) { 453 throw (SecurityException) ex; 454 } else { 455 throw new IOException("Exception: " + ex); 456 } 457 } 458 459 // Install the normal default ErrorManager. 460 setErrorManager(new ErrorManager()); 461 } 462 463 // Generate a filename from a pattern. 464 private File generate(String pattern, int generation, int unique) throws IOException { 465 File file = null; 466 String word = ""; 467 int ix = 0; 468 boolean sawg = false; 469 boolean sawu = false; 470 while (ix < pattern.length()) { 471 char ch = pattern.charAt(ix); 472 ix++; 473 char ch2 = 0; 474 if (ix < pattern.length()) { 475 ch2 = Character.toLowerCase(pattern.charAt(ix)); 476 } 477 if (ch == '/') { 478 if (file == null) { 479 file = new File(word); 480 } else { 481 file = new File(file, word); 482 } 483 word = ""; 484 continue; 485 } else if (ch == '%') { 486 if (ch2 == 't') { 487 String tmpDir = System.getProperty("java.io.tmpdir"); 488 if (tmpDir == null) { 489 tmpDir = System.getProperty("user.home"); 490 } 491 file = new File(tmpDir); 492 ix++; 493 word = ""; 494 continue; 495 } else if (ch2 == 'h') { 496 file = new File(System.getProperty("user.home")); 497 // Android-changed: Don't make a special exemption for setuid programs. 498 // 499 // if (isSetUID()) { 500 // // Ok, we are in a set UID program. For safety's sake 501 // // we disallow attempts to open files relative to %h. 502 // throw new IOException("can't use %h in set UID program"); 503 // } 504 ix++; 505 word = ""; 506 continue; 507 } else if (ch2 == 'g') { 508 word = word + generation; 509 sawg = true; 510 ix++; 511 continue; 512 } else if (ch2 == 'u') { 513 word = word + unique; 514 sawu = true; 515 ix++; 516 continue; 517 } else if (ch2 == '%') { 518 word = word + "%"; 519 ix++; 520 continue; 521 } 522 } 523 word = word + ch; 524 } 525 if (count > 1 && !sawg) { 526 word = word + "." + generation; 527 } 528 if (unique > 0 && !sawu) { 529 word = word + "." + unique; 530 } 531 if (word.length() > 0) { 532 if (file == null) { 533 file = new File(word); 534 } else { 535 file = new File(file, word); 536 } 537 } 538 return file; 539 } 540 541 // Rotate the set of output files 542 private synchronized void rotate() { 543 Level oldLevel = getLevel(); 544 setLevel(Level.OFF); 545 546 super.close(); 547 for (int i = count-2; i >= 0; i--) { 548 File f1 = files[i]; 549 File f2 = files[i+1]; 550 if (f1.exists()) { 551 if (f2.exists()) { 552 f2.delete(); 553 } 554 f1.renameTo(f2); 555 } 556 } 557 try { 558 open(files[0], false); 559 } catch (IOException ix) { 560 // We don't want to throw an exception here, but we 561 // report the exception to any registered ErrorManager. 562 reportError(null, ix, ErrorManager.OPEN_FAILURE); 563 564 } 565 setLevel(oldLevel); 566 } 567 568 /** 569 * Format and publish a <tt>LogRecord</tt>. 570 * 571 * @param record description of the log event. A null record is 572 * silently ignored and is not published 573 */ 574 public synchronized void publish(LogRecord record) { 575 if (!isLoggable(record)) { 576 return; 577 } 578 super.publish(record); 579 flush(); 580 if (limit > 0 && meter.written >= limit) { 581 // We performed access checks in the "init" method to make sure 582 // we are only initialized from trusted code. So we assume 583 // it is OK to write the target files, even if we are 584 // currently being called from untrusted code. 585 // So it is safe to raise privilege here. 586 AccessController.doPrivileged(new PrivilegedAction<Object>() { 587 public Object run() { 588 rotate(); 589 return null; 590 } 591 }); 592 } 593 } 594 595 /** 596 * Close all the files. 597 * 598 * @exception SecurityException if a security manager exists and if 599 * the caller does not have <tt>LoggingPermission("control")</tt>. 600 */ 601 public synchronized void close() throws SecurityException { 602 super.close(); 603 // Unlock any lock file. 604 if (lockFileName == null) { 605 return; 606 } 607 try { 608 // Closing the lock file's FileOutputStream will close 609 // the underlying channel and free any locks. 610 lockStream.close(); 611 } catch (Exception ex) { 612 // Problems closing the stream. Punt. 613 } 614 synchronized(locks) { 615 locks.remove(lockFileName); 616 } 617 new File(lockFileName).delete(); 618 lockFileName = null; 619 lockStream = null; 620 } 621 622 private static class InitializationErrorManager extends ErrorManager { 623 Exception lastException; 624 public void error(String msg, Exception ex, int code) { 625 lastException = ex; 626 } 627 } 628 629 // Private native method to check if we are in a set UID program. 630 // Android-changed: Not required. 631 // private static native boolean isSetUID(); 632} 633