001 /**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License. You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018 package org.apache.hadoop.fs;
019
020
021 import java.io.FileNotFoundException;
022 import java.io.IOException;
023 import java.lang.reflect.Constructor;
024 import java.net.URI;
025 import java.net.URISyntaxException;
026 import java.util.ArrayList;
027 import java.util.EnumSet;
028 import java.util.HashMap;
029 import java.util.List;
030 import java.util.Map;
031 import java.util.NoSuchElementException;
032 import java.util.StringTokenizer;
033 import java.util.concurrent.ConcurrentHashMap;
034
035 import org.apache.commons.logging.Log;
036 import org.apache.commons.logging.LogFactory;
037 import org.apache.hadoop.HadoopIllegalArgumentException;
038 import org.apache.hadoop.classification.InterfaceAudience;
039 import org.apache.hadoop.classification.InterfaceStability;
040 import org.apache.hadoop.conf.Configuration;
041 import org.apache.hadoop.fs.FileSystem.Statistics;
042 import org.apache.hadoop.fs.Options.ChecksumOpt;
043 import org.apache.hadoop.fs.Options.CreateOpts;
044 import org.apache.hadoop.fs.Options.Rename;
045 import org.apache.hadoop.fs.permission.AclEntry;
046 import org.apache.hadoop.fs.permission.AclStatus;
047 import org.apache.hadoop.fs.permission.FsPermission;
048 import org.apache.hadoop.fs.InvalidPathException;
049 import org.apache.hadoop.security.AccessControlException;
050 import org.apache.hadoop.security.SecurityUtil;
051 import org.apache.hadoop.security.token.Token;
052 import org.apache.hadoop.util.Progressable;
053
054 /**
055 * This class provides an interface for implementors of a Hadoop file system
056 * (analogous to the VFS of Unix). Applications do not access this class;
057 * instead they access files across all file systems using {@link FileContext}.
058 *
059 * Pathnames passed to AbstractFileSystem can be fully qualified URI that
060 * matches the "this" file system (ie same scheme and authority)
061 * or a Slash-relative name that is assumed to be relative
062 * to the root of the "this" file system .
063 */
064 @InterfaceAudience.Public
065 @InterfaceStability.Evolving /*Evolving for a release,to be changed to Stable */
066 public abstract class AbstractFileSystem {
067 static final Log LOG = LogFactory.getLog(AbstractFileSystem.class);
068
069 /** Recording statistics per a file system class. */
070 private static final Map<URI, Statistics>
071 STATISTICS_TABLE = new HashMap<URI, Statistics>();
072
073 /** Cache of constructors for each file system class. */
074 private static final Map<Class<?>, Constructor<?>> CONSTRUCTOR_CACHE =
075 new ConcurrentHashMap<Class<?>, Constructor<?>>();
076
077 private static final Class<?>[] URI_CONFIG_ARGS =
078 new Class[]{URI.class, Configuration.class};
079
080 /** The statistics for this file system. */
081 protected Statistics statistics;
082
083 private final URI myUri;
084
085 public Statistics getStatistics() {
086 return statistics;
087 }
088
089 /**
090 * Returns true if the specified string is considered valid in the path part
091 * of a URI by this file system. The default implementation enforces the rules
092 * of HDFS, but subclasses may override this method to implement specific
093 * validation rules for specific file systems.
094 *
095 * @param src String source filename to check, path part of the URI
096 * @return boolean true if the specified string is considered valid
097 */
098 public boolean isValidName(String src) {
099 // Prohibit ".." "." and anything containing ":"
100 StringTokenizer tokens = new StringTokenizer(src, Path.SEPARATOR);
101 while(tokens.hasMoreTokens()) {
102 String element = tokens.nextToken();
103 if (element.equals("..") ||
104 element.equals(".") ||
105 (element.indexOf(":") >= 0)) {
106 return false;
107 }
108 }
109 return true;
110 }
111
112 /**
113 * Create an object for the given class and initialize it from conf.
114 * @param theClass class of which an object is created
115 * @param conf Configuration
116 * @return a new object
117 */
118 @SuppressWarnings("unchecked")
119 static <T> T newInstance(Class<T> theClass,
120 URI uri, Configuration conf) {
121 T result;
122 try {
123 Constructor<T> meth = (Constructor<T>) CONSTRUCTOR_CACHE.get(theClass);
124 if (meth == null) {
125 meth = theClass.getDeclaredConstructor(URI_CONFIG_ARGS);
126 meth.setAccessible(true);
127 CONSTRUCTOR_CACHE.put(theClass, meth);
128 }
129 result = meth.newInstance(uri, conf);
130 } catch (Exception e) {
131 throw new RuntimeException(e);
132 }
133 return result;
134 }
135
136 /**
137 * Create a file system instance for the specified uri using the conf. The
138 * conf is used to find the class name that implements the file system. The
139 * conf is also passed to the file system for its configuration.
140 *
141 * @param uri URI of the file system
142 * @param conf Configuration for the file system
143 *
144 * @return Returns the file system for the given URI
145 *
146 * @throws UnsupportedFileSystemException file system for <code>uri</code> is
147 * not found
148 */
149 public static AbstractFileSystem createFileSystem(URI uri, Configuration conf)
150 throws UnsupportedFileSystemException {
151 Class<?> clazz = conf.getClass("fs.AbstractFileSystem." +
152 uri.getScheme() + ".impl", null);
153 if (clazz == null) {
154 throw new UnsupportedFileSystemException(
155 "No AbstractFileSystem for scheme: " + uri.getScheme());
156 }
157 return (AbstractFileSystem) newInstance(clazz, uri, conf);
158 }
159
160 /**
161 * Get the statistics for a particular file system.
162 *
163 * @param uri
164 * used as key to lookup STATISTICS_TABLE. Only scheme and authority
165 * part of the uri are used.
166 * @return a statistics object
167 */
168 protected static synchronized Statistics getStatistics(URI uri) {
169 String scheme = uri.getScheme();
170 if (scheme == null) {
171 throw new IllegalArgumentException("Scheme not defined in the uri: "
172 + uri);
173 }
174 URI baseUri = getBaseUri(uri);
175 Statistics result = STATISTICS_TABLE.get(baseUri);
176 if (result == null) {
177 result = new Statistics(scheme);
178 STATISTICS_TABLE.put(baseUri, result);
179 }
180 return result;
181 }
182
183 private static URI getBaseUri(URI uri) {
184 String scheme = uri.getScheme();
185 String authority = uri.getAuthority();
186 String baseUriString = scheme + "://";
187 if (authority != null) {
188 baseUriString = baseUriString + authority;
189 } else {
190 baseUriString = baseUriString + "/";
191 }
192 return URI.create(baseUriString);
193 }
194
195 public static synchronized void clearStatistics() {
196 for(Statistics stat: STATISTICS_TABLE.values()) {
197 stat.reset();
198 }
199 }
200
201 /**
202 * Prints statistics for all file systems.
203 */
204 public static synchronized void printStatistics() {
205 for (Map.Entry<URI, Statistics> pair : STATISTICS_TABLE.entrySet()) {
206 System.out.println(" FileSystem " + pair.getKey().getScheme() + "://"
207 + pair.getKey().getAuthority() + ": " + pair.getValue());
208 }
209 }
210
211 protected static synchronized Map<URI, Statistics> getAllStatistics() {
212 Map<URI, Statistics> statsMap = new HashMap<URI, Statistics>(
213 STATISTICS_TABLE.size());
214 for (Map.Entry<URI, Statistics> pair : STATISTICS_TABLE.entrySet()) {
215 URI key = pair.getKey();
216 Statistics value = pair.getValue();
217 Statistics newStatsObj = new Statistics(value);
218 statsMap.put(URI.create(key.toString()), newStatsObj);
219 }
220 return statsMap;
221 }
222
223 /**
224 * The main factory method for creating a file system. Get a file system for
225 * the URI's scheme and authority. The scheme of the <code>uri</code>
226 * determines a configuration property name,
227 * <tt>fs.AbstractFileSystem.<i>scheme</i>.impl</tt> whose value names the
228 * AbstractFileSystem class.
229 *
230 * The entire URI and conf is passed to the AbstractFileSystem factory method.
231 *
232 * @param uri for the file system to be created.
233 * @param conf which is passed to the file system impl.
234 *
235 * @return file system for the given URI.
236 *
237 * @throws UnsupportedFileSystemException if the file system for
238 * <code>uri</code> is not supported.
239 */
240 public static AbstractFileSystem get(final URI uri, final Configuration conf)
241 throws UnsupportedFileSystemException {
242 return createFileSystem(uri, conf);
243 }
244
245 /**
246 * Constructor to be called by subclasses.
247 *
248 * @param uri for this file system.
249 * @param supportedScheme the scheme supported by the implementor
250 * @param authorityNeeded if true then theURI must have authority, if false
251 * then the URI must have null authority.
252 *
253 * @throws URISyntaxException <code>uri</code> has syntax error
254 */
255 public AbstractFileSystem(final URI uri, final String supportedScheme,
256 final boolean authorityNeeded, final int defaultPort)
257 throws URISyntaxException {
258 myUri = getUri(uri, supportedScheme, authorityNeeded, defaultPort);
259 statistics = getStatistics(uri);
260 }
261
262 /**
263 * Check that the Uri's scheme matches
264 * @param uri
265 * @param supportedScheme
266 */
267 public void checkScheme(URI uri, String supportedScheme) {
268 String scheme = uri.getScheme();
269 if (scheme == null) {
270 throw new HadoopIllegalArgumentException("Uri without scheme: " + uri);
271 }
272 if (!scheme.equals(supportedScheme)) {
273 throw new HadoopIllegalArgumentException("Uri scheme " + uri
274 + " does not match the scheme " + supportedScheme);
275 }
276 }
277
278 /**
279 * Get the URI for the file system based on the given URI. The path, query
280 * part of the given URI is stripped out and default file system port is used
281 * to form the URI.
282 *
283 * @param uri FileSystem URI.
284 * @param authorityNeeded if true authority cannot be null in the URI. If
285 * false authority must be null.
286 * @param defaultPort default port to use if port is not specified in the URI.
287 *
288 * @return URI of the file system
289 *
290 * @throws URISyntaxException <code>uri</code> has syntax error
291 */
292 private URI getUri(URI uri, String supportedScheme,
293 boolean authorityNeeded, int defaultPort) throws URISyntaxException {
294 checkScheme(uri, supportedScheme);
295 // A file system implementation that requires authority must always
296 // specify default port
297 if (defaultPort < 0 && authorityNeeded) {
298 throw new HadoopIllegalArgumentException(
299 "FileSystem implementation error - default port " + defaultPort
300 + " is not valid");
301 }
302 String authority = uri.getAuthority();
303 if (authority == null) {
304 if (authorityNeeded) {
305 throw new HadoopIllegalArgumentException("Uri without authority: " + uri);
306 } else {
307 return new URI(supportedScheme + ":///");
308 }
309 }
310 // authority is non null - AuthorityNeeded may be true or false.
311 int port = uri.getPort();
312 port = (port == -1 ? defaultPort : port);
313 if (port == -1) { // no port supplied and default port is not specified
314 return new URI(supportedScheme, authority, "/", null);
315 }
316 return new URI(supportedScheme + "://" + uri.getHost() + ":" + port);
317 }
318
319 /**
320 * The default port of this file system.
321 *
322 * @return default port of this file system's Uri scheme
323 * A uri with a port of -1 => default port;
324 */
325 public abstract int getUriDefaultPort();
326
327 /**
328 * Returns a URI whose scheme and authority identify this FileSystem.
329 *
330 * @return the uri of this file system.
331 */
332 public URI getUri() {
333 return myUri;
334 }
335
336 /**
337 * Check that a Path belongs to this FileSystem.
338 *
339 * If the path is fully qualified URI, then its scheme and authority
340 * matches that of this file system. Otherwise the path must be
341 * slash-relative name.
342 *
343 * @throws InvalidPathException if the path is invalid
344 */
345 public void checkPath(Path path) {
346 URI uri = path.toUri();
347 String thatScheme = uri.getScheme();
348 String thatAuthority = uri.getAuthority();
349 if (thatScheme == null) {
350 if (thatAuthority == null) {
351 if (path.isUriPathAbsolute()) {
352 return;
353 }
354 throw new InvalidPathException("relative paths not allowed:" +
355 path);
356 } else {
357 throw new InvalidPathException(
358 "Path without scheme with non-null authority:" + path);
359 }
360 }
361 String thisScheme = this.getUri().getScheme();
362 String thisHost = this.getUri().getHost();
363 String thatHost = uri.getHost();
364
365 // Schemes and hosts must match.
366 // Allow for null Authority for file:///
367 if (!thisScheme.equalsIgnoreCase(thatScheme) ||
368 (thisHost != null &&
369 !thisHost.equalsIgnoreCase(thatHost)) ||
370 (thisHost == null && thatHost != null)) {
371 throw new InvalidPathException("Wrong FS: " + path + ", expected: "
372 + this.getUri());
373 }
374
375 // Ports must match, unless this FS instance is using the default port, in
376 // which case the port may be omitted from the given URI
377 int thisPort = this.getUri().getPort();
378 int thatPort = uri.getPort();
379 if (thatPort == -1) { // -1 => defaultPort of Uri scheme
380 thatPort = this.getUriDefaultPort();
381 }
382 if (thisPort != thatPort) {
383 throw new InvalidPathException("Wrong FS: " + path + ", expected: "
384 + this.getUri());
385 }
386 }
387
388 /**
389 * Get the path-part of a pathname. Checks that URI matches this file system
390 * and that the path-part is a valid name.
391 *
392 * @param p path
393 *
394 * @return path-part of the Path p
395 */
396 public String getUriPath(final Path p) {
397 checkPath(p);
398 String s = p.toUri().getPath();
399 if (!isValidName(s)) {
400 throw new InvalidPathException("Path part " + s + " from URI " + p
401 + " is not a valid filename.");
402 }
403 return s;
404 }
405
406 /**
407 * Make the path fully qualified to this file system
408 * @param path
409 * @return the qualified path
410 */
411 public Path makeQualified(Path path) {
412 checkPath(path);
413 return path.makeQualified(this.getUri(), null);
414 }
415
416 /**
417 * Some file systems like LocalFileSystem have an initial workingDir
418 * that is used as the starting workingDir. For other file systems
419 * like HDFS there is no built in notion of an initial workingDir.
420 *
421 * @return the initial workingDir if the file system has such a notion
422 * otherwise return a null.
423 */
424 public Path getInitialWorkingDirectory() {
425 return null;
426 }
427
428 /**
429 * Return the current user's home directory in this file system.
430 * The default implementation returns "/user/$USER/".
431 *
432 * @return current user's home directory.
433 */
434 public Path getHomeDirectory() {
435 return new Path("/user/"+System.getProperty("user.name")).makeQualified(
436 getUri(), null);
437 }
438
439 /**
440 * Return a set of server default configuration values.
441 *
442 * @return server default configuration values
443 *
444 * @throws IOException an I/O error occurred
445 */
446 public abstract FsServerDefaults getServerDefaults() throws IOException;
447
448 /**
449 * Return the fully-qualified path of path f resolving the path
450 * through any internal symlinks or mount point
451 * @param p path to be resolved
452 * @return fully qualified path
453 * @throws FileNotFoundException, AccessControlException, IOException
454 * UnresolvedLinkException if symbolic link on path cannot be resolved
455 * internally
456 */
457 public Path resolvePath(final Path p) throws FileNotFoundException,
458 UnresolvedLinkException, AccessControlException, IOException {
459 checkPath(p);
460 return getFileStatus(p).getPath(); // default impl is to return the path
461 }
462
463 /**
464 * The specification of this method matches that of
465 * {@link FileContext#create(Path, EnumSet, Options.CreateOpts...)} except
466 * that the Path f must be fully qualified and the permission is absolute
467 * (i.e. umask has been applied).
468 */
469 public final FSDataOutputStream create(final Path f,
470 final EnumSet<CreateFlag> createFlag, Options.CreateOpts... opts)
471 throws AccessControlException, FileAlreadyExistsException,
472 FileNotFoundException, ParentNotDirectoryException,
473 UnsupportedFileSystemException, UnresolvedLinkException, IOException {
474 checkPath(f);
475 int bufferSize = -1;
476 short replication = -1;
477 long blockSize = -1;
478 int bytesPerChecksum = -1;
479 ChecksumOpt checksumOpt = null;
480 FsPermission permission = null;
481 Progressable progress = null;
482 Boolean createParent = null;
483
484 for (CreateOpts iOpt : opts) {
485 if (CreateOpts.BlockSize.class.isInstance(iOpt)) {
486 if (blockSize != -1) {
487 throw new HadoopIllegalArgumentException(
488 "BlockSize option is set multiple times");
489 }
490 blockSize = ((CreateOpts.BlockSize) iOpt).getValue();
491 } else if (CreateOpts.BufferSize.class.isInstance(iOpt)) {
492 if (bufferSize != -1) {
493 throw new HadoopIllegalArgumentException(
494 "BufferSize option is set multiple times");
495 }
496 bufferSize = ((CreateOpts.BufferSize) iOpt).getValue();
497 } else if (CreateOpts.ReplicationFactor.class.isInstance(iOpt)) {
498 if (replication != -1) {
499 throw new HadoopIllegalArgumentException(
500 "ReplicationFactor option is set multiple times");
501 }
502 replication = ((CreateOpts.ReplicationFactor) iOpt).getValue();
503 } else if (CreateOpts.BytesPerChecksum.class.isInstance(iOpt)) {
504 if (bytesPerChecksum != -1) {
505 throw new HadoopIllegalArgumentException(
506 "BytesPerChecksum option is set multiple times");
507 }
508 bytesPerChecksum = ((CreateOpts.BytesPerChecksum) iOpt).getValue();
509 } else if (CreateOpts.ChecksumParam.class.isInstance(iOpt)) {
510 if (checksumOpt != null) {
511 throw new HadoopIllegalArgumentException(
512 "CreateChecksumType option is set multiple times");
513 }
514 checksumOpt = ((CreateOpts.ChecksumParam) iOpt).getValue();
515 } else if (CreateOpts.Perms.class.isInstance(iOpt)) {
516 if (permission != null) {
517 throw new HadoopIllegalArgumentException(
518 "Perms option is set multiple times");
519 }
520 permission = ((CreateOpts.Perms) iOpt).getValue();
521 } else if (CreateOpts.Progress.class.isInstance(iOpt)) {
522 if (progress != null) {
523 throw new HadoopIllegalArgumentException(
524 "Progress option is set multiple times");
525 }
526 progress = ((CreateOpts.Progress) iOpt).getValue();
527 } else if (CreateOpts.CreateParent.class.isInstance(iOpt)) {
528 if (createParent != null) {
529 throw new HadoopIllegalArgumentException(
530 "CreateParent option is set multiple times");
531 }
532 createParent = ((CreateOpts.CreateParent) iOpt).getValue();
533 } else {
534 throw new HadoopIllegalArgumentException("Unkown CreateOpts of type " +
535 iOpt.getClass().getName());
536 }
537 }
538 if (permission == null) {
539 throw new HadoopIllegalArgumentException("no permission supplied");
540 }
541
542
543 FsServerDefaults ssDef = getServerDefaults();
544 if (ssDef.getBlockSize() % ssDef.getBytesPerChecksum() != 0) {
545 throw new IOException("Internal error: default blockSize is" +
546 " not a multiple of default bytesPerChecksum ");
547 }
548
549 if (blockSize == -1) {
550 blockSize = ssDef.getBlockSize();
551 }
552
553 // Create a checksum option honoring user input as much as possible.
554 // If bytesPerChecksum is specified, it will override the one set in
555 // checksumOpt. Any missing value will be filled in using the default.
556 ChecksumOpt defaultOpt = new ChecksumOpt(
557 ssDef.getChecksumType(),
558 ssDef.getBytesPerChecksum());
559 checksumOpt = ChecksumOpt.processChecksumOpt(defaultOpt,
560 checksumOpt, bytesPerChecksum);
561
562 if (bufferSize == -1) {
563 bufferSize = ssDef.getFileBufferSize();
564 }
565 if (replication == -1) {
566 replication = ssDef.getReplication();
567 }
568 if (createParent == null) {
569 createParent = false;
570 }
571
572 if (blockSize % bytesPerChecksum != 0) {
573 throw new HadoopIllegalArgumentException(
574 "blockSize should be a multiple of checksumsize");
575 }
576
577 return this.createInternal(f, createFlag, permission, bufferSize,
578 replication, blockSize, progress, checksumOpt, createParent);
579 }
580
581 /**
582 * The specification of this method matches that of
583 * {@link #create(Path, EnumSet, Options.CreateOpts...)} except that the opts
584 * have been declared explicitly.
585 */
586 public abstract FSDataOutputStream createInternal(Path f,
587 EnumSet<CreateFlag> flag, FsPermission absolutePermission,
588 int bufferSize, short replication, long blockSize, Progressable progress,
589 ChecksumOpt checksumOpt, boolean createParent)
590 throws AccessControlException, FileAlreadyExistsException,
591 FileNotFoundException, ParentNotDirectoryException,
592 UnsupportedFileSystemException, UnresolvedLinkException, IOException;
593
594 /**
595 * The specification of this method matches that of
596 * {@link FileContext#mkdir(Path, FsPermission, boolean)} except that the Path
597 * f must be fully qualified and the permission is absolute (i.e.
598 * umask has been applied).
599 */
600 public abstract void mkdir(final Path dir, final FsPermission permission,
601 final boolean createParent) throws AccessControlException,
602 FileAlreadyExistsException, FileNotFoundException,
603 UnresolvedLinkException, IOException;
604
605 /**
606 * The specification of this method matches that of
607 * {@link FileContext#delete(Path, boolean)} except that Path f must be for
608 * this file system.
609 */
610 public abstract boolean delete(final Path f, final boolean recursive)
611 throws AccessControlException, FileNotFoundException,
612 UnresolvedLinkException, IOException;
613
614 /**
615 * The specification of this method matches that of
616 * {@link FileContext#open(Path)} except that Path f must be for this
617 * file system.
618 */
619 public FSDataInputStream open(final Path f) throws AccessControlException,
620 FileNotFoundException, UnresolvedLinkException, IOException {
621 return open(f, getServerDefaults().getFileBufferSize());
622 }
623
624 /**
625 * The specification of this method matches that of
626 * {@link FileContext#open(Path, int)} except that Path f must be for this
627 * file system.
628 */
629 public abstract FSDataInputStream open(final Path f, int bufferSize)
630 throws AccessControlException, FileNotFoundException,
631 UnresolvedLinkException, IOException;
632
633 /**
634 * The specification of this method matches that of
635 * {@link FileContext#setReplication(Path, short)} except that Path f must be
636 * for this file system.
637 */
638 public abstract boolean setReplication(final Path f,
639 final short replication) throws AccessControlException,
640 FileNotFoundException, UnresolvedLinkException, IOException;
641
642 /**
643 * The specification of this method matches that of
644 * {@link FileContext#rename(Path, Path, Options.Rename...)} except that Path
645 * f must be for this file system.
646 */
647 public final void rename(final Path src, final Path dst,
648 final Options.Rename... options) throws AccessControlException,
649 FileAlreadyExistsException, FileNotFoundException,
650 ParentNotDirectoryException, UnresolvedLinkException, IOException {
651 boolean overwrite = false;
652 if (null != options) {
653 for (Rename option : options) {
654 if (option == Rename.OVERWRITE) {
655 overwrite = true;
656 }
657 }
658 }
659 renameInternal(src, dst, overwrite);
660 }
661
662 /**
663 * The specification of this method matches that of
664 * {@link FileContext#rename(Path, Path, Options.Rename...)} except that Path
665 * f must be for this file system and NO OVERWRITE is performed.
666 *
667 * File systems that do not have a built in overwrite need implement only this
668 * method and can take advantage of the default impl of the other
669 * {@link #renameInternal(Path, Path, boolean)}
670 */
671 public abstract void renameInternal(final Path src, final Path dst)
672 throws AccessControlException, FileAlreadyExistsException,
673 FileNotFoundException, ParentNotDirectoryException,
674 UnresolvedLinkException, IOException;
675
676 /**
677 * The specification of this method matches that of
678 * {@link FileContext#rename(Path, Path, Options.Rename...)} except that Path
679 * f must be for this file system.
680 */
681 public void renameInternal(final Path src, final Path dst,
682 boolean overwrite) throws AccessControlException,
683 FileAlreadyExistsException, FileNotFoundException,
684 ParentNotDirectoryException, UnresolvedLinkException, IOException {
685 // Default implementation deals with overwrite in a non-atomic way
686 final FileStatus srcStatus = getFileLinkStatus(src);
687
688 FileStatus dstStatus;
689 try {
690 dstStatus = getFileLinkStatus(dst);
691 } catch (IOException e) {
692 dstStatus = null;
693 }
694 if (dstStatus != null) {
695 if (dst.equals(src)) {
696 throw new FileAlreadyExistsException(
697 "The source "+src+" and destination "+dst+" are the same");
698 }
699 if (srcStatus.isSymlink() && dst.equals(srcStatus.getSymlink())) {
700 throw new FileAlreadyExistsException(
701 "Cannot rename symlink "+src+" to its target "+dst);
702 }
703 // It's OK to rename a file to a symlink and vice versa
704 if (srcStatus.isDirectory() != dstStatus.isDirectory()) {
705 throw new IOException("Source " + src + " and destination " + dst
706 + " must both be directories");
707 }
708 if (!overwrite) {
709 throw new FileAlreadyExistsException("Rename destination " + dst
710 + " already exists.");
711 }
712 // Delete the destination that is a file or an empty directory
713 if (dstStatus.isDirectory()) {
714 RemoteIterator<FileStatus> list = listStatusIterator(dst);
715 if (list != null && list.hasNext()) {
716 throw new IOException(
717 "Rename cannot overwrite non empty destination directory " + dst);
718 }
719 }
720 delete(dst, false);
721 } else {
722 final Path parent = dst.getParent();
723 final FileStatus parentStatus = getFileStatus(parent);
724 if (parentStatus.isFile()) {
725 throw new ParentNotDirectoryException("Rename destination parent "
726 + parent + " is a file.");
727 }
728 }
729 renameInternal(src, dst);
730 }
731
732 /**
733 * Returns true if the file system supports symlinks, false otherwise.
734 * @return true if filesystem supports symlinks
735 */
736 public boolean supportsSymlinks() {
737 return false;
738 }
739
740 /**
741 * The specification of this method matches that of
742 * {@link FileContext#createSymlink(Path, Path, boolean)};
743 */
744 public void createSymlink(final Path target, final Path link,
745 final boolean createParent) throws IOException, UnresolvedLinkException {
746 throw new IOException("File system does not support symlinks");
747 }
748
749 /**
750 * Partially resolves the path. This is used during symlink resolution in
751 * {@link FSLinkResolver}, and differs from the similarly named method
752 * {@link FileContext#getLinkTarget(Path)}.
753 */
754 public Path getLinkTarget(final Path f) throws IOException {
755 /* We should never get here. Any file system that threw an
756 * UnresolvedLinkException, causing this function to be called,
757 * needs to override this method.
758 */
759 throw new AssertionError();
760 }
761
762 /**
763 * The specification of this method matches that of
764 * {@link FileContext#setPermission(Path, FsPermission)} except that Path f
765 * must be for this file system.
766 */
767 public abstract void setPermission(final Path f,
768 final FsPermission permission) throws AccessControlException,
769 FileNotFoundException, UnresolvedLinkException, IOException;
770
771 /**
772 * The specification of this method matches that of
773 * {@link FileContext#setOwner(Path, String, String)} except that Path f must
774 * be for this file system.
775 */
776 public abstract void setOwner(final Path f, final String username,
777 final String groupname) throws AccessControlException,
778 FileNotFoundException, UnresolvedLinkException, IOException;
779
780 /**
781 * The specification of this method matches that of
782 * {@link FileContext#setTimes(Path, long, long)} except that Path f must be
783 * for this file system.
784 */
785 public abstract void setTimes(final Path f, final long mtime,
786 final long atime) throws AccessControlException, FileNotFoundException,
787 UnresolvedLinkException, IOException;
788
789 /**
790 * The specification of this method matches that of
791 * {@link FileContext#getFileChecksum(Path)} except that Path f must be for
792 * this file system.
793 */
794 public abstract FileChecksum getFileChecksum(final Path f)
795 throws AccessControlException, FileNotFoundException,
796 UnresolvedLinkException, IOException;
797
798 /**
799 * The specification of this method matches that of
800 * {@link FileContext#getFileStatus(Path)}
801 * except that an UnresolvedLinkException may be thrown if a symlink is
802 * encountered in the path.
803 */
804 public abstract FileStatus getFileStatus(final Path f)
805 throws AccessControlException, FileNotFoundException,
806 UnresolvedLinkException, IOException;
807
808 /**
809 * The specification of this method matches that of
810 * {@link FileContext#getFileLinkStatus(Path)}
811 * except that an UnresolvedLinkException may be thrown if a symlink is
812 * encountered in the path leading up to the final path component.
813 * If the file system does not support symlinks then the behavior is
814 * equivalent to {@link AbstractFileSystem#getFileStatus(Path)}.
815 */
816 public FileStatus getFileLinkStatus(final Path f)
817 throws AccessControlException, FileNotFoundException,
818 UnsupportedFileSystemException, IOException {
819 return getFileStatus(f);
820 }
821
822 /**
823 * The specification of this method matches that of
824 * {@link FileContext#getFileBlockLocations(Path, long, long)} except that
825 * Path f must be for this file system.
826 */
827 public abstract BlockLocation[] getFileBlockLocations(final Path f,
828 final long start, final long len) throws AccessControlException,
829 FileNotFoundException, UnresolvedLinkException, IOException;
830
831 /**
832 * The specification of this method matches that of
833 * {@link FileContext#getFsStatus(Path)} except that Path f must be for this
834 * file system.
835 */
836 public FsStatus getFsStatus(final Path f) throws AccessControlException,
837 FileNotFoundException, UnresolvedLinkException, IOException {
838 // default impl gets FsStatus of root
839 return getFsStatus();
840 }
841
842 /**
843 * The specification of this method matches that of
844 * {@link FileContext#getFsStatus(Path)}.
845 */
846 public abstract FsStatus getFsStatus() throws AccessControlException,
847 FileNotFoundException, IOException;
848
849 /**
850 * The specification of this method matches that of
851 * {@link FileContext#listStatus(Path)} except that Path f must be for this
852 * file system.
853 */
854 public RemoteIterator<FileStatus> listStatusIterator(final Path f)
855 throws AccessControlException, FileNotFoundException,
856 UnresolvedLinkException, IOException {
857 return new RemoteIterator<FileStatus>() {
858 private int i = 0;
859 private FileStatus[] statusList = listStatus(f);
860
861 @Override
862 public boolean hasNext() {
863 return i < statusList.length;
864 }
865
866 @Override
867 public FileStatus next() {
868 if (!hasNext()) {
869 throw new NoSuchElementException();
870 }
871 return statusList[i++];
872 }
873 };
874 }
875
876 /**
877 * The specification of this method matches that of
878 * {@link FileContext#listLocatedStatus(Path)} except that Path f
879 * must be for this file system.
880 */
881 public RemoteIterator<LocatedFileStatus> listLocatedStatus(final Path f)
882 throws AccessControlException, FileNotFoundException,
883 UnresolvedLinkException, IOException {
884 return new RemoteIterator<LocatedFileStatus>() {
885 private RemoteIterator<FileStatus> itor = listStatusIterator(f);
886
887 @Override
888 public boolean hasNext() throws IOException {
889 return itor.hasNext();
890 }
891
892 @Override
893 public LocatedFileStatus next() throws IOException {
894 if (!hasNext()) {
895 throw new NoSuchElementException("No more entry in " + f);
896 }
897 FileStatus result = itor.next();
898 BlockLocation[] locs = null;
899 if (result.isFile()) {
900 locs = getFileBlockLocations(
901 result.getPath(), 0, result.getLen());
902 }
903 return new LocatedFileStatus(result, locs);
904 }
905 };
906 }
907
908 /**
909 * The specification of this method matches that of
910 * {@link FileContext.Util#listStatus(Path)} except that Path f must be
911 * for this file system.
912 */
913 public abstract FileStatus[] listStatus(final Path f)
914 throws AccessControlException, FileNotFoundException,
915 UnresolvedLinkException, IOException;
916
917 /**
918 * @return an iterator over the corrupt files under the given path
919 * (may contain duplicates if a file has more than one corrupt block)
920 * @throws IOException
921 */
922 public RemoteIterator<Path> listCorruptFileBlocks(Path path)
923 throws IOException {
924 throw new UnsupportedOperationException(getClass().getCanonicalName() +
925 " does not support" +
926 " listCorruptFileBlocks");
927 }
928
929 /**
930 * The specification of this method matches that of
931 * {@link FileContext#setVerifyChecksum(boolean, Path)} except that Path f
932 * must be for this file system.
933 */
934 public abstract void setVerifyChecksum(final boolean verifyChecksum)
935 throws AccessControlException, IOException;
936
937 /**
938 * Get a canonical name for this file system.
939 * @return a URI string that uniquely identifies this file system
940 */
941 public String getCanonicalServiceName() {
942 return SecurityUtil.buildDTServiceName(getUri(), getUriDefaultPort());
943 }
944
945 /**
946 * Get one or more delegation tokens associated with the filesystem. Normally
947 * a file system returns a single delegation token. A file system that manages
948 * multiple file systems underneath, could return set of delegation tokens for
949 * all the file systems it manages
950 *
951 * @param renewer the account name that is allowed to renew the token.
952 * @return List of delegation tokens.
953 * If delegation tokens not supported then return a list of size zero.
954 * @throws IOException
955 */
956 @InterfaceAudience.LimitedPrivate( { "HDFS", "MapReduce" })
957 public List<Token<?>> getDelegationTokens(String renewer) throws IOException {
958 return new ArrayList<Token<?>>(0);
959 }
960
961 /**
962 * Modifies ACL entries of files and directories. This method can add new ACL
963 * entries or modify the permissions on existing ACL entries. All existing
964 * ACL entries that are not specified in this call are retained without
965 * changes. (Modifications are merged into the current ACL.)
966 *
967 * @param path Path to modify
968 * @param aclSpec List<AclEntry> describing modifications
969 * @throws IOException if an ACL could not be modified
970 */
971 public void modifyAclEntries(Path path, List<AclEntry> aclSpec)
972 throws IOException {
973 throw new UnsupportedOperationException(getClass().getSimpleName()
974 + " doesn't support modifyAclEntries");
975 }
976
977 /**
978 * Removes ACL entries from files and directories. Other ACL entries are
979 * retained.
980 *
981 * @param path Path to modify
982 * @param aclSpec List<AclEntry> describing entries to remove
983 * @throws IOException if an ACL could not be modified
984 */
985 public void removeAclEntries(Path path, List<AclEntry> aclSpec)
986 throws IOException {
987 throw new UnsupportedOperationException(getClass().getSimpleName()
988 + " doesn't support removeAclEntries");
989 }
990
991 /**
992 * Removes all default ACL entries from files and directories.
993 *
994 * @param path Path to modify
995 * @throws IOException if an ACL could not be modified
996 */
997 public void removeDefaultAcl(Path path)
998 throws IOException {
999 throw new UnsupportedOperationException(getClass().getSimpleName()
1000 + " doesn't support removeDefaultAcl");
1001 }
1002
1003 /**
1004 * Removes all but the base ACL entries of files and directories. The entries
1005 * for user, group, and others are retained for compatibility with permission
1006 * bits.
1007 *
1008 * @param path Path to modify
1009 * @throws IOException if an ACL could not be removed
1010 */
1011 public void removeAcl(Path path)
1012 throws IOException {
1013 throw new UnsupportedOperationException(getClass().getSimpleName()
1014 + " doesn't support removeAcl");
1015 }
1016
1017 /**
1018 * Fully replaces ACL of files and directories, discarding all existing
1019 * entries.
1020 *
1021 * @param path Path to modify
1022 * @param aclSpec List<AclEntry> describing modifications, must include entries
1023 * for user, group, and others for compatibility with permission bits.
1024 * @throws IOException if an ACL could not be modified
1025 */
1026 public void setAcl(Path path, List<AclEntry> aclSpec) throws IOException {
1027 throw new UnsupportedOperationException(getClass().getSimpleName()
1028 + " doesn't support setAcl");
1029 }
1030
1031 /**
1032 * Gets the ACLs of files and directories.
1033 *
1034 * @param path Path to get
1035 * @return RemoteIterator<AclStatus> which returns each AclStatus
1036 * @throws IOException if an ACL could not be read
1037 */
1038 public AclStatus getAclStatus(Path path) throws IOException {
1039 throw new UnsupportedOperationException(getClass().getSimpleName()
1040 + " doesn't support getAclStatus");
1041 }
1042
1043 @Override //Object
1044 public int hashCode() {
1045 return myUri.hashCode();
1046 }
1047
1048 @Override //Object
1049 public boolean equals(Object other) {
1050 if (other == null || !(other instanceof AbstractFileSystem)) {
1051 return false;
1052 }
1053 return myUri.equals(((AbstractFileSystem) other).myUri);
1054 }
1055 }