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 {@code Handler}.
  52  * <p>
  53  * The {@code FileHandler} 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 {@code XMLFormatter} class is used for formatting.
  65  * <p>
  66  * <b>Configuration:</b>
  67  * By default each {@code FileHandler} is initialized using the following
  68  * {@code LogManager} configuration properties where {@code <handler-name>}
  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>   &lt;handler-name&gt;.level
  74  *        specifies the default level for the {@code Handler}
  75  *        (defaults to {@code Level.ALL}). </li>
  76  * <li>   &lt;handler-name&gt;.filter
  77  *        specifies the name of a {@code Filter} class to use
  78  *        (defaults to no {@code Filter}). </li>
  79  * <li>   &lt;handler-name&gt;.formatter
  80  *        specifies the name of a {@code Formatter} class to use
  81  *        (defaults to {@code java.util.logging.XMLFormatter}) </li>
  82  * <li>   &lt;handler-name&gt;.encoding
  83  *        the name of the character set encoding to use (defaults to
  84  *        the default platform encoding). </li>
  85  * <li>   &lt;handler-name&gt;.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>   &lt;handler-name&gt;.count
  90  *        specifies how many output files to cycle through (defaults to 1). </li>
  91  * <li>   &lt;handler-name&gt;.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>   &lt;handler-name&gt;.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 {@code FileHandler}
 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 {@code FileHandler} 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 long 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 static final class MeteredStream extends OutputStream {
 168         final OutputStream out;
 169         long written;
 170 
 171         MeteredStream(OutputStream out, long 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         long len = 0;
 207         if (append) {
 208             len = 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.getLongProperty(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 {@code FileHandler}.  This will be configured
 253      * entirely from {@code LogManager} 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 {@code LoggingPermission("control"))}.
 258      * @exception  NullPointerException if pattern property is an empty String.
 259      */
 260     public FileHandler() throws IOException, SecurityException {
 261         checkPermission();
 262         configure();
 263         // pattern will have been set by configure. check that it's not
 264         // empty.
 265         if (pattern.isEmpty()) {
 266             throw new NullPointerException();
 267         }
 268         openFiles();
 269     }
 270 
 271     /**
 272      * Initialize a {@code FileHandler} to write to the given filename.
 273      * <p>
 274      * The {@code FileHandler} is configured based on {@code LogManager}
 275      * properties (or their default values) except that the given pattern
 276      * argument is used as the filename pattern, the file limit is
 277      * set to no limit, and the file count is set to one.
 278      * <p>
 279      * There is no limit on the amount of data that may be written,
 280      * so use this with care.
 281      *
 282      * @param pattern  the name of the output file
 283      * @exception  IOException if there are IO problems opening the files.
 284      * @exception  SecurityException  if a security manager exists and if
 285      *             the caller does not have {@code LoggingPermission("control")}.
 286      * @exception  IllegalArgumentException if pattern is an empty string
 287      */
 288     public FileHandler(String pattern) throws IOException, SecurityException {
 289         if (pattern.length() < 1 ) {
 290             throw new IllegalArgumentException();
 291         }
 292         checkPermission();
 293         configure();
 294         this.pattern = pattern;
 295         this.limit = 0;
 296         this.count = 1;
 297         openFiles();
 298     }
 299 
 300     /**
 301      * Initialize a {@code FileHandler} to write to the given filename,
 302      * with optional append.
 303      * <p>
 304      * The {@code FileHandler} is configured based on {@code LogManager}
 305      * properties (or their default values) except that the given pattern
 306      * argument is used as the filename pattern, the file limit is
 307      * set to no limit, the file count is set to one, and the append
 308      * mode is set to the given {@code append} argument.
 309      * <p>
 310      * There is no limit on the amount of data that may be written,
 311      * so use this with care.
 312      *
 313      * @param pattern  the name of the output file
 314      * @param append  specifies append mode
 315      * @exception  IOException if there are IO problems opening the files.
 316      * @exception  SecurityException  if a security manager exists and if
 317      *             the caller does not have {@code LoggingPermission("control")}.
 318      * @exception  IllegalArgumentException if pattern is an empty string
 319      */
 320     public FileHandler(String pattern, boolean append) throws IOException,
 321             SecurityException {
 322         if (pattern.length() < 1 ) {
 323             throw new IllegalArgumentException();
 324         }
 325         checkPermission();
 326         configure();
 327         this.pattern = pattern;
 328         this.limit = 0;
 329         this.count = 1;
 330         this.append = append;
 331         openFiles();
 332     }
 333 
 334     /**
 335      * Initialize a {@code FileHandler} to write to a set of files.  When
 336      * (approximately) the given limit has been written to one file,
 337      * another file will be opened.  The output will cycle through a set
 338      * of count files.
 339      * <p>
 340      * The {@code FileHandler} is configured based on {@code LogManager}
 341      * properties (or their default values) except that the given pattern
 342      * argument is used as the filename pattern, the file limit is
 343      * set to the limit argument, and the file count is set to the
 344      * given count argument.
 345      * <p>
 346      * The count must be at least 1.
 347      *
 348      * @param pattern  the pattern for naming the output file
 349      * @param limit  the maximum number of bytes to write to any one file
 350      * @param count  the number of files to use
 351      * @exception  IOException if there are IO problems opening the files.
 352      * @exception  SecurityException  if a security manager exists and if
 353      *             the caller does not have {@code LoggingPermission("control")}.
 354      * @exception  IllegalArgumentException if {@code limit < 0}, or {@code count < 1}.
 355      * @exception  IllegalArgumentException if pattern is an empty string
 356      */
 357     public FileHandler(String pattern, int limit, int count)
 358                                         throws IOException, SecurityException {
 359         if (limit < 0 || count < 1 || pattern.length() < 1) {
 360             throw new IllegalArgumentException();
 361         }
 362         checkPermission();
 363         configure();
 364         this.pattern = pattern;
 365         this.limit = limit;
 366         this.count = count;
 367         openFiles();
 368     }
 369 
 370     /**
 371      * Initialize a {@code FileHandler} to write to a set of files
 372      * with optional append.  When (approximately) the given limit has
 373      * been written to one file, another file will be opened.  The
 374      * output will cycle through a set of count files.
 375      * <p>
 376      * The {@code FileHandler} is configured based on {@code LogManager}
 377      * properties (or their default values) except that the given pattern
 378      * argument is used as the filename pattern, the file limit is
 379      * set to the limit argument, and the file count is set to the
 380      * given count argument, and the append mode is set to the given
 381      * {@code append} argument.
 382      * <p>
 383      * The count must be at least 1.
 384      *
 385      * @param pattern  the pattern for naming the output file
 386      * @param limit  the maximum number of bytes to write to any one file
 387      * @param count  the number of files to use
 388      * @param append  specifies append mode
 389      * @exception  IOException if there are IO problems opening the files.
 390      * @exception  SecurityException  if a security manager exists and if
 391      *             the caller does not have {@code LoggingPermission("control")}.
 392      * @exception  IllegalArgumentException if {@code limit < 0}, or {@code count < 1}.
 393      * @exception  IllegalArgumentException if pattern is an empty string
 394      *
 395      */
 396     public FileHandler(String pattern, int limit, int count, boolean append)
 397                                         throws IOException, SecurityException {
 398         this(pattern, (long)limit, count, append);
 399     }
 400 
 401     /**
 402      * Initialize a {@code FileHandler} to write to a set of files
 403      * with optional append.  When (approximately) the given limit has
 404      * been written to one file, another file will be opened.  The
 405      * output will cycle through a set of count files.
 406      * <p>
 407      * The {@code FileHandler} is configured based on {@code LogManager}
 408      * properties (or their default values) except that the given pattern
 409      * argument is used as the filename pattern, the file limit is
 410      * set to the limit argument, and the file count is set to the
 411      * given count argument, and the append mode is set to the given
 412      * {@code append} argument.
 413      * <p>
 414      * The count must be at least 1.
 415      *
 416      * @param pattern  the pattern for naming the output file
 417      * @param limit  the maximum number of bytes to write to any one file
 418      * @param count  the number of files to use
 419      * @param append  specifies append mode
 420      * @exception  IOException if there are IO problems opening the files.
 421      * @exception  SecurityException  if a security manager exists and if
 422      *             the caller does not have {@code LoggingPermission("control")}.
 423      * @exception  IllegalArgumentException if {@code limit < 0}, or {@code count < 1}.
 424      * @exception  IllegalArgumentException if pattern is an empty string
 425      *
 426      * @since 1.9
 427      *
 428      */
 429     public FileHandler(String pattern, long limit, int count, boolean append)
 430                                         throws IOException {
 431         if (limit < 0 || count < 1 || pattern.length() < 1) {
 432             throw new IllegalArgumentException();
 433         }
 434         checkPermission();
 435         configure();
 436         this.pattern = pattern;
 437         this.limit = limit;
 438         this.count = count;
 439         this.append = append;
 440         openFiles();
 441     }
 442 
 443     private  boolean isParentWritable(Path path) {
 444         Path parent = path.getParent();
 445         if (parent == null) {
 446             parent = path.toAbsolutePath().getParent();
 447         }
 448         return parent != null && Files.isWritable(parent);
 449     }
 450 
 451     /**
 452      * Open the set of output files, based on the configured
 453      * instance variables.
 454      */
 455     private void openFiles() throws IOException {
 456         LogManager manager = LogManager.getLogManager();
 457         manager.checkPermission();
 458         if (count < 1) {
 459            throw new IllegalArgumentException("file count = " + count);
 460         }
 461         if (limit < 0) {
 462             limit = 0;
 463         }
 464 
 465         // All constructors check that pattern is neither null nor empty.
 466         assert pattern != null : "pattern should not be null";
 467         assert !pattern.isEmpty() : "pattern should not be empty";
 468 
 469         // We register our own ErrorManager during initialization
 470         // so we can record exceptions.
 471         InitializationErrorManager em = new InitializationErrorManager();
 472         setErrorManager(em);
 473 
 474         // Create a lock file.  This grants us exclusive access
 475         // to our set of output files, as long as we are alive.
 476         int unique = -1;
 477         for (;;) {
 478             unique++;
 479             if (unique > MAX_LOCKS) {
 480                 throw new IOException("Couldn't get lock for " + pattern);
 481             }
 482             // Generate a lock file name from the "unique" int.
 483             lockFileName = generate(pattern, 0, unique).toString() + ".lck";
 484             // Now try to lock that filename.
 485             // Because some systems (e.g., Solaris) can only do file locks
 486             // between processes (and not within a process), we first check
 487             // if we ourself already have the file locked.
 488             synchronized(locks) {
 489                 if (locks.contains(lockFileName)) {
 490                     // We already own this lock, for a different FileHandler
 491                     // object.  Try again.
 492                     continue;
 493                 }
 494 
 495                 final Path lockFilePath = Paths.get(lockFileName);
 496                 FileChannel channel = null;
 497                 int retries = -1;
 498                 boolean fileCreated = false;
 499                 while (channel == null && retries++ < 1) {
 500                     try {
 501                         channel = FileChannel.open(lockFilePath,
 502                                 CREATE_NEW, WRITE);
 503                         fileCreated = true;
 504                     } catch (FileAlreadyExistsException ix) {
 505                         // This may be a zombie file left over by a previous
 506                         // execution. Reuse it - but only if we can actually
 507                         // write to its directory.
 508                         // Note that this is a situation that may happen,
 509                         // but not too frequently.
 510                         if (Files.isRegularFile(lockFilePath, LinkOption.NOFOLLOW_LINKS)
 511                             && isParentWritable(lockFilePath)) {
 512                             try {
 513                                 channel = FileChannel.open(lockFilePath,
 514                                     WRITE, APPEND);
 515                             } catch (NoSuchFileException x) {
 516                                 // Race condition - retry once, and if that
 517                                 // fails again just try the next name in
 518                                 // the sequence.
 519                                 continue;
 520                             } catch(IOException x) {
 521                                 // the file may not be writable for us.
 522                                 // try the next name in the sequence
 523                                 break;
 524                             }
 525                         } else {
 526                             // at this point channel should still be null.
 527                             // break and try the next name in the sequence.
 528                             break;
 529                         }
 530                     }
 531                 }
 532 
 533                 if (channel == null) continue; // try the next name;
 534                 lockFileChannel = channel;
 535 
 536                 boolean available;
 537                 try {
 538                     available = lockFileChannel.tryLock() != null;
 539                     // We got the lock OK.
 540                     // At this point we could call File.deleteOnExit().
 541                     // However, this could have undesirable side effects
 542                     // as indicated by JDK-4872014. So we will instead
 543                     // rely on the fact that close() will remove the lock
 544                     // file and that whoever is creating FileHandlers should
 545                     // be responsible for closing them.
 546                 } catch (IOException ix) {
 547                     // We got an IOException while trying to get the lock.
 548                     // This normally indicates that locking is not supported
 549                     // on the target directory.  We have to proceed without
 550                     // getting a lock.   Drop through, but only if we did
 551                     // create the file...
 552                     available = fileCreated;
 553                 } catch (OverlappingFileLockException x) {
 554                     // someone already locked this file in this VM, through
 555                     // some other channel - that is - using something else
 556                     // than new FileHandler(...);
 557                     // continue searching for an available lock.
 558                     available = false;
 559                 }
 560                 if (available) {
 561                     // We got the lock.  Remember it.
 562                     locks.add(lockFileName);
 563                     break;
 564                 }
 565 
 566                 // We failed to get the lock.  Try next file.
 567                 lockFileChannel.close();
 568             }
 569         }
 570 
 571         files = new File[count];
 572         for (int i = 0; i < count; i++) {
 573             files[i] = generate(pattern, i, unique);
 574         }
 575 
 576         // Create the initial log file.
 577         if (append) {
 578             open(files[0], true);
 579         } else {
 580             rotate();
 581         }
 582 
 583         // Did we detect any exceptions during initialization?
 584         Exception ex = em.lastException;
 585         if (ex != null) {
 586             if (ex instanceof IOException) {
 587                 throw (IOException) ex;
 588             } else if (ex instanceof SecurityException) {
 589                 throw (SecurityException) ex;
 590             } else {
 591                 throw new IOException("Exception: " + ex);
 592             }
 593         }
 594 
 595         // Install the normal default ErrorManager.
 596         setErrorManager(new ErrorManager());
 597     }
 598 
 599     /**
 600      * Generate a file based on a user-supplied pattern, generation number,
 601      * and an integer uniqueness suffix
 602      * @param pattern the pattern for naming the output file
 603      * @param generation the generation number to distinguish rotated logs
 604      * @param unique a unique number to resolve conflicts
 605      * @return the generated File
 606      * @throws IOException
 607      */
 608     private File generate(String pattern, int generation, int unique)
 609             throws IOException {
 610         File file = null;
 611         String word = "";
 612         int ix = 0;
 613         boolean sawg = false;
 614         boolean sawu = false;
 615         while (ix < pattern.length()) {
 616             char ch = pattern.charAt(ix);
 617             ix++;
 618             char ch2 = 0;
 619             if (ix < pattern.length()) {
 620                 ch2 = Character.toLowerCase(pattern.charAt(ix));
 621             }
 622             if (ch == '/') {
 623                 if (file == null) {
 624                     file = new File(word);
 625                 } else {
 626                     file = new File(file, word);
 627                 }
 628                 word = "";
 629                 continue;
 630             } else  if (ch == '%') {
 631                 if (ch2 == 't') {
 632                     String tmpDir = System.getProperty("java.io.tmpdir");
 633                     if (tmpDir == null) {
 634                         tmpDir = System.getProperty("user.home");
 635                     }
 636                     file = new File(tmpDir);
 637                     ix++;
 638                     word = "";
 639                     continue;
 640                 } else if (ch2 == 'h') {
 641                     file = new File(System.getProperty("user.home"));
 642                     if (jdk.internal.misc.VM.isSetUID()) {
 643                         // Ok, we are in a set UID program.  For safety's sake
 644                         // we disallow attempts to open files relative to %h.
 645                         throw new IOException("can't use %h in set UID program");
 646                     }
 647                     ix++;
 648                     word = "";
 649                     continue;
 650                 } else if (ch2 == 'g') {
 651                     word = word + generation;
 652                     sawg = true;
 653                     ix++;
 654                     continue;
 655                 } else if (ch2 == 'u') {
 656                     word = word + unique;
 657                     sawu = true;
 658                     ix++;
 659                     continue;
 660                 } else if (ch2 == '%') {
 661                     word = word + "%";
 662                     ix++;
 663                     continue;
 664                 }
 665             }
 666             word = word + ch;
 667         }
 668         if (count > 1 && !sawg) {
 669             word = word + "." + generation;
 670         }
 671         if (unique > 0 && !sawu) {
 672             word = word + "." + unique;
 673         }
 674         if (word.length() > 0) {
 675             if (file == null) {
 676                 file = new File(word);
 677             } else {
 678                 file = new File(file, word);
 679             }
 680         }
 681         return file;
 682     }
 683 
 684     /**
 685      * Rotate the set of output files
 686      */
 687     private synchronized void rotate() {
 688         Level oldLevel = getLevel();
 689         setLevel(Level.OFF);
 690 
 691         super.close();
 692         for (int i = count-2; i >= 0; i--) {
 693             File f1 = files[i];
 694             File f2 = files[i+1];
 695             if (f1.exists()) {
 696                 if (f2.exists()) {
 697                     f2.delete();
 698                 }
 699                 f1.renameTo(f2);
 700             }
 701         }
 702         try {
 703             open(files[0], false);
 704         } catch (IOException ix) {
 705             // We don't want to throw an exception here, but we
 706             // report the exception to any registered ErrorManager.
 707             reportError(null, ix, ErrorManager.OPEN_FAILURE);
 708 
 709         }
 710         setLevel(oldLevel);
 711     }
 712 
 713     /**
 714      * Format and publish a {@code LogRecord}.
 715      *
 716      * @param  record  description of the log event. A null record is
 717      *                 silently ignored and is not published
 718      */
 719     @Override
 720     public synchronized void publish(LogRecord record) {
 721         if (!isLoggable(record)) {
 722             return;
 723         }
 724         super.publish(record);
 725         flush();
 726         if (limit > 0 && (meter.written >= limit || meter.written < 0)) {
 727             // We performed access checks in the "init" method to make sure
 728             // we are only initialized from trusted code.  So we assume
 729             // it is OK to write the target files, even if we are
 730             // currently being called from untrusted code.
 731             // So it is safe to raise privilege here.
 732             AccessController.doPrivileged(new PrivilegedAction<Object>() {
 733                 @Override
 734                 public Object run() {
 735                     rotate();
 736                     return null;
 737                 }
 738             });
 739         }
 740     }
 741 
 742     /**
 743      * Close all the files.
 744      *
 745      * @exception  SecurityException  if a security manager exists and if
 746      *             the caller does not have {@code LoggingPermission("control")}.
 747      */
 748     @Override
 749     public synchronized void close() throws SecurityException {
 750         super.close();
 751         // Unlock any lock file.
 752         if (lockFileName == null) {
 753             return;
 754         }
 755         try {
 756             // Close the lock file channel (which also will free any locks)
 757             lockFileChannel.close();
 758         } catch (Exception ex) {
 759             // Problems closing the stream.  Punt.
 760         }
 761         synchronized(locks) {
 762             locks.remove(lockFileName);
 763         }
 764         new File(lockFileName).delete();
 765         lockFileName = null;
 766         lockFileChannel = null;
 767     }
 768 
 769     private static class InitializationErrorManager extends ErrorManager {
 770         Exception lastException;
 771         @Override
 772         public void error(String msg, Exception ex, int code) {
 773             lastException = ex;
 774         }
 775     }
 776 }