HDFS-6570. add api that enables checking if a user has certain permissions on a file. Contributed by Jitendra Pandey.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1614723 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/AbstractFileSystem.java

@@ -43,6 +43,7 @@
 import org.apache.hadoop.fs.Options.Rename;
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclStatus;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.fs.InvalidPathException;
 import org.apache.hadoop.security.AccessControlException;
@@ -803,6 +804,18 @@ public abstract FileStatus getFileStatus(final Path f)
       throws AccessControlException, FileNotFoundException,
       UnresolvedLinkException, IOException;
 
+  /**
+   * The specification of this method matches that of
+   * {@link FileContext#access(Path, FsAction)}
+   * except that an UnresolvedLinkException may be thrown if a symlink is
+   * encountered in the path.
+   */
+  @InterfaceAudience.LimitedPrivate({"HDFS", "Hive"})
+  public void access(Path path, FsAction mode) throws AccessControlException,
+      FileNotFoundException, UnresolvedLinkException, IOException {
+    FileSystem.checkAccessPermissions(this.getFileStatus(path), mode);
+  }
+
   /**
    * The specification of this method matches that of
    * {@link FileContext#getFileLinkStatus(Path)}

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileContext.java

@@ -44,6 +44,7 @@
 import org.apache.hadoop.fs.Options.CreateOpts;
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclStatus;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
 import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.FS_DEFAULT_NAME_KEY;
 import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.FS_DEFAULT_NAME_DEFAULT;
@@ -1108,6 +1109,55 @@ public FileStatus next(final AbstractFileSystem fs, final Path p)
     }.resolve(this, absF);
   }
 
+  /**
+   * Checks if the user can access a path.  The mode specifies which access
+   * checks to perform.  If the requested permissions are granted, then the
+   * method returns normally.  If access is denied, then the method throws an
+   * {@link AccessControlException}.
+   * <p/>
+   * The default implementation of this method calls {@link #getFileStatus(Path)}
+   * and checks the returned permissions against the requested permissions.
+   * Note that the getFileStatus call will be subject to authorization checks.
+   * Typically, this requires search (execute) permissions on each directory in
+   * the path's prefix, but this is implementation-defined.  Any file system
+   * that provides a richer authorization model (such as ACLs) may override the
+   * default implementation so that it checks against that model instead.
+   * <p>
+   * In general, applications should avoid using this method, due to the risk of
+   * time-of-check/time-of-use race conditions.  The permissions on a file may
+   * change immediately after the access call returns.  Most applications should
+   * prefer running specific file system actions as the desired user represented
+   * by a {@link UserGroupInformation}.
+   *
+   * @param path Path to check
+   * @param mode type of access to check
+   * @throws AccessControlException if access is denied
+   * @throws FileNotFoundException if the path does not exist
+   * @throws UnsupportedFileSystemException if file system for <code>path</code>
+   *   is not supported
+   * @throws IOException see specific implementation
+   * 
+   * Exceptions applicable to file systems accessed over RPC:
+   * @throws RpcClientException If an exception occurred in the RPC client
+   * @throws RpcServerException If an exception occurred in the RPC server
+   * @throws UnexpectedServerException If server implementation throws 
+   *           undeclared exception to RPC server
+   */
+  @InterfaceAudience.LimitedPrivate({"HDFS", "Hive"})
+  public void access(final Path path, final FsAction mode)
+      throws AccessControlException, FileNotFoundException,
+      UnsupportedFileSystemException, IOException {
+    final Path absPath = fixRelativePart(path);
+    new FSLinkResolver<Void>() {
+      @Override
+      public Void next(AbstractFileSystem fs, Path p) throws IOException,
+          UnresolvedLinkException {
+        fs.access(p, mode);
+        return null;
+      }
+    }.resolve(this, absPath);
+  }
+
   /**
    * Return a file status object that represents the path. If the path 
    * refers to a symlink then the FileStatus of the symlink is returned.

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileSystem.java

@@ -25,6 +25,7 @@
 import java.net.URISyntaxException;
 import java.security.PrivilegedExceptionAction;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -50,6 +51,7 @@
 import org.apache.hadoop.fs.Options.Rename;
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclStatus;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.io.MultipleIOException;
 import org.apache.hadoop.io.Text;
@@ -2072,6 +2074,71 @@ public short getDefaultReplication(Path path) {
    */
   public abstract FileStatus getFileStatus(Path f) throws IOException;
 
+  /**
+   * Checks if the user can access a path.  The mode specifies which access
+   * checks to perform.  If the requested permissions are granted, then the
+   * method returns normally.  If access is denied, then the method throws an
+   * {@link AccessControlException}.
+   * <p/>
+   * The default implementation of this method calls {@link #getFileStatus(Path)}
+   * and checks the returned permissions against the requested permissions.
+   * Note that the getFileStatus call will be subject to authorization checks.
+   * Typically, this requires search (execute) permissions on each directory in
+   * the path's prefix, but this is implementation-defined.  Any file system
+   * that provides a richer authorization model (such as ACLs) may override the
+   * default implementation so that it checks against that model instead.
+   * <p>
+   * In general, applications should avoid using this method, due to the risk of
+   * time-of-check/time-of-use race conditions.  The permissions on a file may
+   * change immediately after the access call returns.  Most applications should
+   * prefer running specific file system actions as the desired user represented
+   * by a {@link UserGroupInformation}.
+   *
+   * @param path Path to check
+   * @param mode type of access to check
+   * @throws AccessControlException if access is denied
+   * @throws FileNotFoundException if the path does not exist
+   * @throws IOException see specific implementation
+   */
+  @InterfaceAudience.LimitedPrivate({"HDFS", "Hive"})
+  public void access(Path path, FsAction mode) throws AccessControlException,
+      FileNotFoundException, IOException {
+    checkAccessPermissions(this.getFileStatus(path), mode);
+  }
+
+  /**
+   * This method provides the default implementation of
+   * {@link #access(Path, FsAction)}.
+   *
+   * @param stat FileStatus to check
+   * @param mode type of access to check
+   * @throws IOException for any error
+   */
+  @InterfaceAudience.Private
+  static void checkAccessPermissions(FileStatus stat, FsAction mode)
+      throws IOException {
+    FsPermission perm = stat.getPermission();
+    UserGroupInformation ugi = UserGroupInformation.getCurrentUser();
+    String user = ugi.getShortUserName();
+    List<String> groups = Arrays.asList(ugi.getGroupNames());
+    if (user.equals(stat.getOwner())) {
+      if (perm.getUserAction().implies(mode)) {
+        return;
+      }
+    } else if (groups.contains(stat.getGroup())) {
+      if (perm.getGroupAction().implies(mode)) {
+        return;
+      }
+    } else {
+      if (perm.getOtherAction().implies(mode)) {
+        return;
+      }
+    }
+    throw new AccessControlException(String.format(
+      "Permission denied: user=%s, path=\"%s\":%s:%s:%s%s", user, stat.getPath(),
+      stat.getOwner(), stat.getGroup(), stat.isDirectory() ? "d" : "-", perm));
+  }
+
   /**
    * See {@link FileContext#fixRelativePart}
    */

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FilterFileSystem.java

@@ -30,6 +30,7 @@
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclStatus;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.fs.Options.ChecksumOpt;
 import org.apache.hadoop.security.AccessControlException;
@@ -397,6 +398,12 @@ public FileStatus getFileStatus(Path f) throws IOException {
     return fs.getFileStatus(f);
   }
 
+  @Override
+  public void access(Path path, FsAction mode) throws AccessControlException,
+      FileNotFoundException, IOException {
+    fs.access(path, mode);
+  }
+
   public void createSymlink(final Path target, final Path link,
       final boolean createParent) throws AccessControlException,
       FileAlreadyExistsException, FileNotFoundException,

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FilterFs.java

@@ -29,6 +29,7 @@
 import org.apache.hadoop.fs.FileSystem.Statistics;
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclStatus;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.fs.Options.ChecksumOpt;
 import org.apache.hadoop.security.AccessControlException;
@@ -119,6 +120,13 @@ public FileStatus getFileStatus(Path f)
     return myFs.getFileStatus(f);
   }
 
+  @Override
+  public void access(Path path, FsAction mode) throws AccessControlException,
+      FileNotFoundException, UnresolvedLinkException, IOException {
+    checkPath(path);
+    myFs.access(path, mode);
+  }
+
   @Override
   public FileStatus getFileLinkStatus(final Path f) 
     throws IOException, UnresolvedLinkException {

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/viewfs/ChRootedFileSystem.java

@@ -41,7 +41,9 @@
 import org.apache.hadoop.fs.XAttrSetFlag;
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclStatus;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.security.AccessControlException;
 import org.apache.hadoop.util.Progressable;
 
 /**
@@ -222,6 +224,12 @@ public FileStatus getFileStatus(final Path f)
     return super.getFileStatus(fullPath(f));
   }
 
+  @Override
+  public void access(Path path, FsAction mode) throws AccessControlException,
+      FileNotFoundException, IOException {
+    super.access(fullPath(path), mode);
+  }
+
   @Override
   public FsStatus getStatus(Path p) throws IOException {
     return super.getStatus(fullPath(p));

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/viewfs/ChRootedFs.java

@@ -41,7 +41,9 @@
 import org.apache.hadoop.fs.XAttrSetFlag;
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclStatus;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.security.AccessControlException;
 import org.apache.hadoop.security.token.Token;
 import org.apache.hadoop.util.Progressable;
 
@@ -200,6 +202,11 @@ public FileStatus getFileStatus(final Path f)
     return myFs.getFileStatus(fullPath(f));
   }
 
+  public void access(Path path, FsAction mode) throws AccessControlException,
+      FileNotFoundException, UnresolvedLinkException, IOException {
+    myFs.access(fullPath(path), mode);
+  }
+
   @Override
   public FileStatus getFileLinkStatus(final Path f) 
     throws IOException, UnresolvedLinkException {

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/viewfs/ViewFileSystem.java

@@ -51,6 +51,7 @@
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclStatus;
 import org.apache.hadoop.fs.permission.AclUtil;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.fs.viewfs.InodeTree.INode;
 import org.apache.hadoop.fs.viewfs.InodeTree.INodeLink;
@@ -359,7 +360,14 @@ public FileStatus getFileStatus(final Path f) throws AccessControlException,
     return new ViewFsFileStatus(status, this.makeQualified(f));
   }
   
-  
+  @Override
+  public void access(Path path, FsAction mode) throws AccessControlException,
+      FileNotFoundException, IOException {
+    InodeTree.ResolveResult<FileSystem> res =
+      fsState.resolve(getUriPath(path), true);
+    res.targetFileSystem.access(res.remainingPath, mode);
+  }
+
   @Override
   public FileStatus[] listStatus(final Path f) throws AccessControlException,
       FileNotFoundException, IOException {

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/viewfs/ViewFs.java

@@ -54,6 +54,7 @@
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclUtil;
 import org.apache.hadoop.fs.permission.AclStatus;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.fs.viewfs.InodeTree.INode;
 import org.apache.hadoop.fs.viewfs.InodeTree.INodeLink;
@@ -352,6 +353,14 @@ public FileStatus getFileStatus(final Path f) throws AccessControlException,
     return new ViewFsFileStatus(status, this.makeQualified(f));
   }
 
+  @Override
+  public void access(Path path, FsAction mode) throws AccessControlException,
+      FileNotFoundException, UnresolvedLinkException, IOException {
+    InodeTree.ResolveResult<AbstractFileSystem> res =
+      fsState.resolve(getUriPath(path), true);
+    res.targetFileSystem.access(res.remainingPath, mode);
+  }
+
   @Override
   public FileStatus getFileLinkStatus(final Path f)
      throws AccessControlException, FileNotFoundException,

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestHarFileSystem.java

@@ -23,6 +23,7 @@
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclStatus;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.security.Credentials;
 import org.apache.hadoop.security.token.Token;
@@ -201,6 +202,8 @@ public Map<String, byte[]> getXAttrs(Path path, List<String> names)
     public void removeXAttr(Path path, String name) throws IOException;
 
     public AclStatus getAclStatus(Path path) throws IOException;
+
+    public void access(Path path, FsAction mode) throws IOException;
   }
 
   @Test

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -332,6 +332,9 @@ Release 2.6.0 - UNRELEASED
     HDFS-6778. The extended attributes javadoc should simply refer to the
     user docs. (clamb via wang)
 
+    HDFS-6570. add api that enables checking if a user has certain permissions on
+    a file. (Jitendra Pandey via cnauroth)
+
   OPTIMIZATIONS
 
     HDFS-6690. Deduplicate xattr names in memory. (wang)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/fs/Hdfs.java

@@ -33,6 +33,7 @@
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclStatus;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.fs.Options.ChecksumOpt;
 import org.apache.hadoop.hdfs.CorruptFileBlockIterator;
@@ -448,6 +449,11 @@ public void removeXAttr(Path path, String name) throws IOException {
     dfs.removeXAttr(getUriPath(path), name);
   }
 
+  @Override
+  public void access(Path path, final FsAction mode) throws IOException {
+    dfs.checkAccess(getUriPath(path), mode);
+  }
+
   /**
    * Renew an existing delegation token.
    * 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSClient.java

@@ -122,6 +122,7 @@
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclStatus;
 import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.hdfs.client.HdfsDataInputStream;
 import org.apache.hadoop.hdfs.client.HdfsDataOutputStream;
 import org.apache.hadoop.hdfs.net.Peer;
@@ -2832,6 +2833,17 @@ public void removeXAttr(String src, String name) throws IOException {
     }
   }
 
+  public void checkAccess(String src, FsAction mode) throws IOException {
+    checkOpen();
+    try {
+      namenode.checkAccess(src, mode);
+    } catch (RemoteException re) {
+      throw re.unwrapRemoteException(AccessControlException.class,
+          FileNotFoundException.class,
+          UnresolvedPathException.class);
+    }
+  }
+
   @Override // RemotePeerFactory
   public Peer newConnectedPeer(InetSocketAddress addr,
       Token<BlockTokenIdentifier> blockToken, DatanodeID datanodeId)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DistributedFileSystem.java

@@ -59,6 +59,7 @@
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclStatus;
 import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.hdfs.client.HdfsAdmin;
 import org.apache.hadoop.hdfs.client.HdfsDataInputStream;
 import org.apache.hadoop.hdfs.client.HdfsDataOutputStream;
@@ -1898,4 +1899,23 @@ public Void next(final FileSystem fs, final Path p) throws IOException {
       }
     }.resolve(this, absF);
   }
+
+  @Override
+  public void access(Path path, final FsAction mode) throws IOException {
+    final Path absF = fixRelativePart(path);
+    new FileSystemLinkResolver<Void>() {
+      @Override
+      public Void doCall(final Path p) throws IOException {
+        dfs.checkAccess(getPathName(p), mode);
+        return null;
+      }
+
+      @Override
+      public Void next(final FileSystem fs, final Path p)
+          throws IOException {
+        fs.access(p, mode);
+        return null;
+      }
+    }.resolve(this, absF);
+  }
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/ClientProtocol.java

@@ -39,6 +39,7 @@
 import org.apache.hadoop.fs.XAttrSetFlag;
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclStatus;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.RollingUpgradeAction;
@@ -1327,4 +1328,22 @@ public List<XAttr> listXAttrs(String src)
    */
   @AtMostOnce
   public void removeXAttr(String src, XAttr xAttr) throws IOException;
+
+  /**
+   * Checks if the user can access a path.  The mode specifies which access
+   * checks to perform.  If the requested permissions are granted, then the
+   * method returns normally.  If access is denied, then the method throws an
+   * {@link AccessControlException}.
+   * In general, applications should avoid using this method, due to the risk of
+   * time-of-check/time-of-use race conditions.  The permissions on a file may
+   * change immediately after the access call returns.
+   *
+   * @param path Path to check
+   * @param mode type of access to check
+   * @throws AccessControlException if access is denied
+   * @throws FileNotFoundException if the path does not exist
+   * @throws IOException see specific implementation
+   */
+  @Idempotent
+  public void checkAccess(String path, FsAction mode) throws IOException;
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/ClientNamenodeProtocolServerSideTranslatorPB.java

@@ -174,6 +174,8 @@
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.UpdateBlockForPipelineResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.UpdatePipelineRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.UpdatePipelineResponseProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CheckAccessRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CheckAccessResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.DatanodeIDProto;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.DatanodeInfoProto;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.LocatedBlockProto;
@@ -320,6 +322,9 @@ public class ClientNamenodeProtocolServerSideTranslatorPB implements
   private static final RemoveXAttrResponseProto
     VOID_REMOVEXATTR_RESPONSE = RemoveXAttrResponseProto.getDefaultInstance();
 
+  private static final CheckAccessResponseProto
+    VOID_CHECKACCESS_RESPONSE = CheckAccessResponseProto.getDefaultInstance();
+
   /**
    * Constructor
    * 
@@ -1338,4 +1343,15 @@ public RemoveXAttrResponseProto removeXAttr(RpcController controller,
     }
     return VOID_REMOVEXATTR_RESPONSE;
   }
+
+  @Override
+  public CheckAccessResponseProto checkAccess(RpcController controller,
+     CheckAccessRequestProto req) throws ServiceException {
+    try {
+      server.checkAccess(req.getPath(), PBHelper.convert(req.getMode()));
+    } catch (IOException e) {
+      throw new ServiceException(e);
+    }
+    return VOID_CHECKACCESS_RESPONSE;
+  }
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/ClientNamenodeProtocolTranslatorPB.java

@@ -39,6 +39,7 @@
 import org.apache.hadoop.fs.XAttrSetFlag;
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclStatus;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.hdfs.protocol.AlreadyBeingCreatedException;
 import org.apache.hadoop.hdfs.protocol.CacheDirectiveEntry;
@@ -144,6 +145,7 @@
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.SetTimesRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.UpdateBlockForPipelineRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.UpdatePipelineRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CheckAccessRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.XAttrProtos.GetXAttrsRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.XAttrProtos.ListXAttrsRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.XAttrProtos.RemoveXAttrRequestProto;
@@ -1346,4 +1348,15 @@ public void removeXAttr(String src, XAttr xAttr) throws IOException {
       throw ProtobufHelper.getRemoteException(e);
     }
   }
+
+  @Override
+  public void checkAccess(String path, FsAction mode) throws IOException {
+    CheckAccessRequestProto req = CheckAccessRequestProto.newBuilder()
+        .setPath(path).setMode(PBHelper.convert(mode)).build();
+    try {
+      rpcProxy.checkAccess(null, req);
+    } catch (ServiceException e) {
+      throw ProtobufHelper.getRemoteException(e);
+    }
+  }
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/PBHelper.java

@@ -2107,11 +2107,11 @@ private static XAttr.NameSpace convert(XAttrNamespaceProto v) {
     return castEnum(v, XATTR_NAMESPACE_VALUES);
   }
 
-  private static FsActionProto convert(FsAction v) {
+  public static FsActionProto convert(FsAction v) {
     return FsActionProto.valueOf(v != null ? v.ordinal() : 0);
   }
 
-  private static FsAction convert(FsActionProto v) {
+  public static FsAction convert(FsActionProto v) {
     return castEnum(v, FSACTION_VALUES);
   }
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java

@@ -8458,6 +8458,29 @@ private void checkXAttrChangeAccess(String src, XAttr xAttr,
     }
   }
 
+  void checkAccess(String src, FsAction mode) throws AccessControlException,
+      FileNotFoundException, UnresolvedLinkException, IOException {
+    checkOperation(OperationCategory.READ);
+    byte[][] pathComponents = FSDirectory.getPathComponentsForReservedPath(src);
+    readLock();
+    try {
+      checkOperation(OperationCategory.READ);
+      src = FSDirectory.resolvePath(src, pathComponents, dir);
+      if (dir.getINode(src) == null) {
+        throw new FileNotFoundException("Path not found");
+      }
+      if (isPermissionEnabled) {
+        FSPermissionChecker pc = getPermissionChecker();
+        checkPathAccess(pc, src, mode);
+      }
+    } catch (AccessControlException e) {
+      logAuditEvent(false, "checkAccess", src);
+      throw e;
+    } finally {
+      readUnlock();
+    }
+  }
+
   /**
    * Default AuditLogger implementation; used when no access logger is
    * defined in the config file. It can also be explicitly listed in the

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NameNodeRpcServer.java

@@ -54,6 +54,7 @@
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclStatus;
 import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.PermissionStatus;
 import org.apache.hadoop.ha.HAServiceStatus;
 import org.apache.hadoop.ha.HealthCheckFailedException;
@@ -1443,5 +1444,10 @@ public List<XAttr> listXAttrs(String src) throws IOException {
   public void removeXAttr(String src, XAttr xAttr) throws IOException {
     namesystem.removeXAttr(src, xAttr);
   }
+
+  @Override
+  public void checkAccess(String path, FsAction mode) throws IOException {
+    namesystem.checkAccess(path, mode);
+  }
 }
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/web/resources/NamenodeWebHdfsMethods.java

@@ -57,6 +57,7 @@
 import org.apache.hadoop.fs.Options;
 import org.apache.hadoop.fs.XAttr;
 import org.apache.hadoop.fs.permission.AclStatus;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.hdfs.StorageType;
 import org.apache.hadoop.hdfs.XAttrHelper;
 import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
@@ -112,6 +113,7 @@
 import org.apache.hadoop.hdfs.web.resources.XAttrNameParam;
 import org.apache.hadoop.hdfs.web.resources.XAttrSetFlagParam;
 import org.apache.hadoop.hdfs.web.resources.XAttrValueParam;
+import org.apache.hadoop.hdfs.web.resources.FsActionParam;
 import org.apache.hadoop.io.Text;
 import org.apache.hadoop.ipc.RetriableException;
 import org.apache.hadoop.ipc.Server;
@@ -755,10 +757,12 @@ public Response getRoot(
       @QueryParam(XAttrEncodingParam.NAME) @DefaultValue(XAttrEncodingParam.DEFAULT) 
           final XAttrEncodingParam xattrEncoding,
       @QueryParam(ExcludeDatanodesParam.NAME) @DefaultValue(ExcludeDatanodesParam.DEFAULT)
-          final ExcludeDatanodesParam excludeDatanodes          
+          final ExcludeDatanodesParam excludeDatanodes,
+      @QueryParam(FsActionParam.NAME) @DefaultValue(FsActionParam.DEFAULT)
+          final FsActionParam fsAction
       ) throws IOException, InterruptedException {
     return get(ugi, delegation, username, doAsUser, ROOT, op, offset, length,
-        renewer, bufferSize, xattrNames, xattrEncoding, excludeDatanodes);
+        renewer, bufferSize, xattrNames, xattrEncoding, excludeDatanodes, fsAction);
   }
 
   /** Handle HTTP GET request. */
@@ -789,11 +793,13 @@ public Response get(
       @QueryParam(XAttrEncodingParam.NAME) @DefaultValue(XAttrEncodingParam.DEFAULT) 
           final XAttrEncodingParam xattrEncoding,
       @QueryParam(ExcludeDatanodesParam.NAME) @DefaultValue(ExcludeDatanodesParam.DEFAULT)
-          final ExcludeDatanodesParam excludeDatanodes
+          final ExcludeDatanodesParam excludeDatanodes,
+      @QueryParam(FsActionParam.NAME) @DefaultValue(FsActionParam.DEFAULT)
+          final FsActionParam fsAction
       ) throws IOException, InterruptedException {
 
     init(ugi, delegation, username, doAsUser, path, op, offset, length,
-        renewer, bufferSize, xattrEncoding, excludeDatanodes);
+        renewer, bufferSize, xattrEncoding, excludeDatanodes, fsAction);
 
     return ugi.doAs(new PrivilegedExceptionAction<Response>() {
       @Override
@@ -801,7 +807,7 @@ public Response run() throws IOException, URISyntaxException {
         try {
           return get(ugi, delegation, username, doAsUser,
               path.getAbsolutePath(), op, offset, length, renewer, bufferSize,
-              xattrNames, xattrEncoding, excludeDatanodes);
+              xattrNames, xattrEncoding, excludeDatanodes, fsAction);
         } finally {
           reset();
         }
@@ -822,7 +828,8 @@ private Response get(
       final BufferSizeParam bufferSize,
       final List<XAttrNameParam> xattrNames,
       final XAttrEncodingParam xattrEncoding,
-      final ExcludeDatanodesParam excludeDatanodes
+      final ExcludeDatanodesParam excludeDatanodes,
+      final FsActionParam fsAction
       ) throws IOException, URISyntaxException {
     final NameNode namenode = (NameNode)context.getAttribute("name.node");
     final NamenodeProtocols np = getRPCServer(namenode);
@@ -919,6 +926,10 @@ private Response get(
       final String js = JsonUtil.toJsonString(xAttrs);
       return Response.ok(js).type(MediaType.APPLICATION_JSON).build();
     }
+    case CHECKACCESS: {
+      np.checkAccess(fullpath, FsAction.getFsAction(fsAction.getValue()));
+      return Response.ok().build();
+    }
     default:
       throw new UnsupportedOperationException(op + " is not supported");
     }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/web/WebHdfsFileSystem.java

@@ -54,6 +54,7 @@
 import org.apache.hadoop.fs.XAttrSetFlag;
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclStatus;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DFSUtil;
@@ -1356,6 +1357,12 @@ BlockLocation[] decodeResponse(Map<?,?> json) throws IOException {
     }.run();
   }
 
+  @Override
+  public void access(final Path path, final FsAction mode) throws IOException {
+    final HttpOpParam.Op op = GetOpParam.Op.CHECKACCESS;
+    new FsPathRunner(op, path, new FsActionParam(mode)).run();
+  }
+
   @Override
   public ContentSummary getContentSummary(final Path p) throws IOException {
     statistics.incrementReadOps(1);

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/web/resources/FsActionParam.java

@@ -0,0 +1,58 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.web.resources;
+
+import org.apache.hadoop.fs.permission.FsAction;
+
+import java.util.regex.Pattern;
+
+/** {@link FsAction} Parameter */
+public class FsActionParam extends StringParam {
+
+  /** Parameter name. */
+  public static final String NAME = "fsaction";
+
+  /** Default parameter value. */
+  public static final String DEFAULT = NULL;
+
+  private static String FS_ACTION_PATTERN = "[rwx-]{3}";
+
+  private static final Domain DOMAIN = new Domain(NAME,
+      Pattern.compile(FS_ACTION_PATTERN));
+
+  /**
+   * Constructor.
+   * @param str a string representation of the parameter value.
+   */
+  public FsActionParam(final String str) {
+    super(DOMAIN, str == null || str.equals(DEFAULT)? null: str);
+  }
+
+  /**
+   * Constructor.
+   * @param value the parameter value.
+   */
+  public FsActionParam(final FsAction value) {
+    super(DOMAIN, value == null? null: value.SYMBOL);
+  }
+
+  @Override
+  public String getName() {
+    return NAME;
+  }
+}

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/web/resources/GetOpParam.java

@@ -39,7 +39,9 @@ public static enum Op implements HttpOpParam.Op {
     GETXATTRS(false, HttpURLConnection.HTTP_OK),
     LISTXATTRS(false, HttpURLConnection.HTTP_OK),
 
-    NULL(false, HttpURLConnection.HTTP_NOT_IMPLEMENTED);
+    NULL(false, HttpURLConnection.HTTP_NOT_IMPLEMENTED),
+
+    CHECKACCESS(false, HttpURLConnection.HTTP_OK);
 
     final boolean redirect;
     final int expectedHttpResponseCode;

hadoop-hdfs-project/hadoop-hdfs/src/main/proto/ClientNamenodeProtocol.proto

@@ -654,6 +654,14 @@ message DeleteSnapshotRequestProto {
 message DeleteSnapshotResponseProto { // void response
 }
 
+message CheckAccessRequestProto {
+  required string path = 1;
+  required AclEntryProto.FsActionProto mode = 2;
+}
+
+message CheckAccessResponseProto { // void response
+}
+
 service ClientNamenodeProtocol {
   rpc getBlockLocations(GetBlockLocationsRequestProto)
       returns(GetBlockLocationsResponseProto);
@@ -783,4 +791,6 @@ service ClientNamenodeProtocol {
       returns(ListXAttrsResponseProto);
   rpc removeXAttr(RemoveXAttrRequestProto)
       returns(RemoveXAttrResponseProto);
+  rpc checkAccess(CheckAccessRequestProto)
+      returns(CheckAccessResponseProto);
 }

hadoop-hdfs-project/hadoop-hdfs/src/site/apt/WebHDFS.apt.vm

@@ -82,6 +82,9 @@ WebHDFS REST API
     * {{{List all XAttrs}<<<LISTXATTRS>>>}}
         (see  {{{../../api/org/apache/hadoop/fs/FileSystem.html}FileSystem}}.listXAttrs)
 
+    * {{{Check access}<<<CHECKACCESS>>>}}
+        (see  {{{../../api/org/apache/hadoop/fs/FileSystem.html}FileSystem}}.access)
+
   * HTTP PUT
 
     * {{{Create and Write to a File}<<<CREATE>>>}}
@@ -927,6 +930,28 @@ Transfer-Encoding: chunked
   {{{../../api/org/apache/hadoop/fs/FileSystem.html}FileSystem}}.getAclStatus
 
 
+** {Check access}
+
+  * Submit a HTTP GET request.
+  
++---------------------------------
+curl -i -X PUT "http://<HOST>:<PORT>/webhdfs/v1/<PATH>?op=CHECKACCESS
+                              &fsaction=<FSACTION>
++---------------------------------
+
+  The client receives a response with zero content length:
+
++---------------------------------
+HTTP/1.1 200 OK
+Content-Length: 0
++---------------------------------
+
+  []
+
+  See also:
+  {{{../../api/org/apache/hadoop/fs/FileSystem.html}FileSystem}}.access
+    
+
 * {Extended Attributes(XAttrs) Operations}
 
 ** {Set XAttr}
@@ -2166,6 +2191,25 @@ var tokenProperties =
   {{Proxy Users}}
 
 
+** {Fs Action}
+
+*----------------+-------------------------------------------------------------------+
+|| Name          | <<<fsaction>>> |
+*----------------+-------------------------------------------------------------------+
+|| Description   | File system operation read/write/execute |
+*----------------+-------------------------------------------------------------------+
+|| Type          | String |
+*----------------+-------------------------------------------------------------------+
+|| Default Value | null (an invalid value) |
+*----------------+-------------------------------------------------------------------+
+|| Valid Values  | Strings matching regex pattern \"[rwx-]\{3\}\" |
+*----------------+-------------------------------------------------------------------+
+|| Syntax        | \"[rwx-]\{3\}\" |
+*----------------+-------------------------------------------------------------------+
+
+  See also:
+  {{{Check access}<<<CHECKACCESS>>>}},
+
 ** {Group}
 
 *----------------+-------------------------------------------------------------------+

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSPermission.java

@@ -20,8 +20,11 @@
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
+import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.security.PrivilegedExceptionAction;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Random;
@@ -36,6 +39,7 @@
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.security.AccessControlException;
 import org.apache.hadoop.security.UserGroupInformation;
 import org.apache.hadoop.util.Time;
@@ -421,6 +425,79 @@ public void testPermissionChecking() throws Exception {
     }
   }
 
+  @Test
+  public void testAccessOwner() throws IOException, InterruptedException {
+    FileSystem rootFs = FileSystem.get(conf);
+    Path p1 = new Path("/p1");
+    rootFs.mkdirs(p1);
+    rootFs.setOwner(p1, USER1_NAME, GROUP1_NAME);
+    fs = USER1.doAs(new PrivilegedExceptionAction<FileSystem>() {
+      @Override
+      public FileSystem run() throws Exception {
+        return FileSystem.get(conf);
+      }
+    });
+    fs.setPermission(p1, new FsPermission((short) 0444));
+    fs.access(p1, FsAction.READ);
+    try {
+      fs.access(p1, FsAction.WRITE);
+      fail("The access call should have failed.");
+    } catch (AccessControlException e) {
+      // expected
+    }
+
+    Path badPath = new Path("/bad/bad");
+    try {
+      fs.access(badPath, FsAction.READ);
+      fail("The access call should have failed");
+    } catch (FileNotFoundException e) {
+      // expected
+    }
+  }
+
+  @Test
+  public void testAccessGroupMember() throws IOException, InterruptedException {
+    FileSystem rootFs = FileSystem.get(conf);
+    Path p2 = new Path("/p2");
+    rootFs.mkdirs(p2);
+    rootFs.setOwner(p2, UserGroupInformation.getCurrentUser().getShortUserName(), GROUP1_NAME);
+    rootFs.setPermission(p2, new FsPermission((short) 0740));
+    fs = USER1.doAs(new PrivilegedExceptionAction<FileSystem>() {
+      @Override
+      public FileSystem run() throws Exception {
+        return FileSystem.get(conf);
+      }
+    });
+    fs.access(p2, FsAction.READ);
+    try {
+      fs.access(p2, FsAction.EXECUTE);
+      fail("The access call should have failed.");
+    } catch (AccessControlException e) {
+      // expected
+    }
+  }
+
+  @Test
+  public void testAccessOthers() throws IOException, InterruptedException {
+    FileSystem rootFs = FileSystem.get(conf);
+    Path p3 = new Path("/p3");
+    rootFs.mkdirs(p3);
+    rootFs.setPermission(p3, new FsPermission((short) 0774));
+    fs = USER1.doAs(new PrivilegedExceptionAction<FileSystem>() {
+      @Override
+      public FileSystem run() throws Exception {
+        return FileSystem.get(conf);
+      }
+    });
+    fs.access(p3, FsAction.READ);
+    try {
+      fs.access(p3, FsAction.READ_WRITE);
+      fail("The access call should have failed.");
+    } catch (AccessControlException e) {
+      // expected
+    }
+  }
+
   /* Check if namenode performs permission checking correctly 
    * for the given user for operations mkdir, open, setReplication, 
    * getFileInfo, isDirectory, exists, getContentLength, list, rename,

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestSafeMode.java

@@ -26,6 +26,7 @@
 import static org.junit.Assert.fail;
 
 import java.io.IOException;
+import java.security.PrivilegedExceptionAction;
 import java.util.List;
 
 import org.apache.commons.logging.Log;
@@ -36,6 +37,7 @@
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.fs.permission.AclEntry;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.hdfs.MiniDFSCluster.DataNodeProperties;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.SafeModeAction;
@@ -47,6 +49,8 @@
 import org.apache.hadoop.hdfs.server.namenode.SafeModeException;
 import org.apache.hadoop.io.IOUtils;
 import org.apache.hadoop.ipc.RemoteException;
+import org.apache.hadoop.security.AccessControlException;
+import org.apache.hadoop.security.UserGroupInformation;
 import org.apache.hadoop.test.GenericTestUtils;
 import org.junit.After;
 import org.junit.Before;
@@ -297,7 +301,8 @@ public void runFsFun(String msg, FSRun f) {
    * assert that they are either allowed or fail as expected.
    */
   @Test
-  public void testOperationsWhileInSafeMode() throws IOException {
+  public void testOperationsWhileInSafeMode() throws IOException,
+      InterruptedException {
     final Path file1 = new Path("/file1");
 
     assertFalse(dfs.setSafeMode(SafeModeAction.SAFEMODE_GET));
@@ -407,6 +412,22 @@ public void run(FileSystem fs) throws IOException {
       fail("getAclStatus failed while in SM");
     }
 
+    // Test access
+    UserGroupInformation ugiX = UserGroupInformation.createRemoteUser("userX");
+    FileSystem myfs = ugiX.doAs(new PrivilegedExceptionAction<FileSystem>() {
+      @Override
+      public FileSystem run() throws IOException {
+        return FileSystem.get(conf);
+      }
+    });
+    myfs.access(file1, FsAction.READ);
+    try {
+      myfs.access(file1, FsAction.WRITE);
+      fail("The access call should have failed.");
+    } catch (AccessControlException e) {
+      // expected
+    }
+
     assertFalse("Could not leave SM",
         dfs.setSafeMode(SafeModeAction.SAFEMODE_LEAVE));
   }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/FSAclBaseTest.java

@@ -34,6 +34,7 @@
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclStatus;
 import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DFSTestUtil;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
@@ -1256,6 +1257,33 @@ public void testGetAclStatusRequiresTraverseOrSuper() throws Exception {
     fsAsDiana.getAclStatus(bruceFile);
   }
 
+  @Test
+  public void testAccess() throws IOException, InterruptedException {
+    Path p1 = new Path("/p1");
+    fs.mkdirs(p1);
+    fs.setOwner(p1, BRUCE.getShortUserName(), "groupX");
+    fsAsBruce.setAcl(p1, Lists.newArrayList(
+        aclEntry(ACCESS, USER, READ),
+        aclEntry(ACCESS, USER, "bruce", READ),
+        aclEntry(ACCESS, GROUP, NONE),
+        aclEntry(ACCESS, OTHER, NONE)));
+    fsAsBruce.access(p1, FsAction.READ);
+    try {
+      fsAsBruce.access(p1, FsAction.WRITE);
+      fail("The access call should have failed.");
+    } catch (AccessControlException e) {
+      // expected
+    }
+
+    Path badPath = new Path("/bad/bad");
+    try {
+      fsAsBruce.access(badPath, FsAction.READ);
+      fail("The access call should have failed");
+    } catch (FileNotFoundException e) {
+      // expected
+    }
+  }
+
   /**
    * Creates a FileSystem for the super-user.
    *

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestINodeFile.java

@@ -45,6 +45,7 @@
 import org.apache.hadoop.fs.PathIsNotDirectoryException;
 import org.apache.hadoop.fs.RemoteIterator;
 import org.apache.hadoop.fs.XAttr;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.fs.permission.PermissionStatus;
 import org.apache.hadoop.hdfs.DFSClient;
@@ -581,6 +582,7 @@ public void testInodeIdBasedPaths() throws Exception {
         fs.getAclStatus(testFileInodePath);
         fs.getXAttrs(testFileInodePath);
         fs.listXAttrs(testFileInodePath);
+        fs.access(testFileInodePath, FsAction.READ_WRITE);
       }
       
       // symbolic link related tests

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/snapshot/TestAclWithSnapshot.java

@@ -30,6 +30,7 @@
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.AclStatus;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DFSTestUtil;
@@ -674,6 +675,13 @@ private static void assertDirPermissionDenied(FileSystem fs,
     } catch (AccessControlException e) {
       // expected
     }
+
+    try {
+      fs.access(pathToCheck, FsAction.READ);
+      fail("The access call should have failed for "+pathToCheck);
+    } catch (AccessControlException e) {
+      // expected
+    }
   }
 
   /**
@@ -689,6 +697,7 @@ private static void assertDirPermissionGranted(FileSystem fs,
       UserGroupInformation user, Path pathToCheck) throws Exception {
     try {
       fs.listStatus(pathToCheck);
+      fs.access(pathToCheck, FsAction.READ);
     } catch (AccessControlException e) {
       fail("expected permission granted for user " + user + ", path = " +
         pathToCheck);

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/web/TestWebHdfsFileSystemContract.java

@@ -39,6 +39,7 @@
 import org.apache.hadoop.fs.FileStatus;
 import org.apache.hadoop.fs.FileSystemContractBaseTest;
 import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.hdfs.AppendTestUtil;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
@@ -49,6 +50,7 @@
 import org.apache.hadoop.security.AccessControlException;
 import org.apache.hadoop.security.UserGroupInformation;
 import org.junit.Assert;
+import org.junit.Test;
 
 public class TestWebHdfsFileSystemContract extends FileSystemContractBaseTest {
   private static final Configuration conf = new Configuration();
@@ -530,4 +532,35 @@ public void testResponseCode() throws IOException {
       }
     }
   }
+
+  @Test
+  public void testAccess() throws IOException, InterruptedException {
+    Path p1 = new Path("/pathX");
+    try {
+      UserGroupInformation ugi = UserGroupInformation.createUserForTesting("alpha",
+          new String[]{"beta"});
+      WebHdfsFileSystem fs = WebHdfsTestUtil.getWebHdfsFileSystemAs(ugi, conf,
+          WebHdfsFileSystem.SCHEME);
+
+      fs.mkdirs(p1);
+      fs.setPermission(p1, new FsPermission((short) 0444));
+      fs.access(p1, FsAction.READ);
+      try {
+        fs.access(p1, FsAction.WRITE);
+        fail("The access call should have failed.");
+      } catch (AccessControlException e) {
+        // expected
+      }
+
+      Path badPath = new Path("/bad");
+      try {
+        fs.access(badPath, FsAction.READ);
+        fail("The access call should have failed");
+      } catch (FileNotFoundException e) {
+        // expected
+      }
+    } finally {
+      fs.delete(p1, true);
+    }
+  }
 }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/web/TestWebHdfsUrl.java

@@ -31,6 +31,7 @@
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenIdentifier;
 import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenSecretManager;
 import org.apache.hadoop.hdfs.server.namenode.FSNamesystem;
@@ -40,6 +41,7 @@
 import org.apache.hadoop.hdfs.web.resources.PutOpParam;
 import org.apache.hadoop.hdfs.web.resources.TokenArgumentParam;
 import org.apache.hadoop.hdfs.web.resources.UserParam;
+import org.apache.hadoop.hdfs.web.resources.FsActionParam;
 import org.apache.hadoop.io.Text;
 import org.apache.hadoop.net.NetUtils;
 import org.apache.hadoop.security.SecurityUtil;
@@ -283,6 +285,28 @@ public void testSecureProxyAuthParamsInUrl() throws IOException {
         },
         fileStatusUrl);    
   }
+
+  @Test(timeout=60000)
+  public void testCheckAccessUrl() throws IOException {
+    Configuration conf = new Configuration();
+
+    UserGroupInformation ugi =
+        UserGroupInformation.createRemoteUser("test-user");
+    UserGroupInformation.setLoginUser(ugi);
+
+    WebHdfsFileSystem webhdfs = getWebHdfsFileSystem(ugi, conf);
+    Path fsPath = new Path("/p1");
+
+    URL checkAccessUrl = webhdfs.toUrl(GetOpParam.Op.CHECKACCESS,
+        fsPath, new FsActionParam(FsAction.READ_WRITE));
+    checkQueryParams(
+        new String[]{
+            GetOpParam.Op.CHECKACCESS.toQueryString(),
+            new UserParam(ugi.getShortUserName()).toString(),
+            FsActionParam.NAME + "=" + FsAction.READ_WRITE.SYMBOL
+        },
+        checkAccessUrl);
+  }
   
   private void checkQueryParams(String[] expected, URL url) {
     Arrays.sort(expected);

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/security/TestPermissionSymlinks.java

@@ -27,6 +27,7 @@
 import static org.junit.Assert.fail;
 
 import java.io.IOException;
+import java.io.FileNotFoundException;
 import java.security.PrivilegedExceptionAction;
 import java.util.Arrays;
 
@@ -39,6 +40,7 @@
 import org.apache.hadoop.fs.FileSystemTestWrapper;
 import org.apache.hadoop.fs.Options.Rename;
 import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DFSTestUtil;
@@ -393,4 +395,37 @@ public Object run() throws IOException {
       GenericTestUtils.assertExceptionContains("Permission denied", e);
     }
   }
+
+  @Test
+  public void testAccess() throws Exception {
+    fs.setPermission(target, new FsPermission((short) 0002));
+    fs.setAcl(target, Arrays.asList(
+        aclEntry(ACCESS, USER, ALL),
+        aclEntry(ACCESS, GROUP, NONE),
+        aclEntry(ACCESS, USER, user.getShortUserName(), WRITE),
+        aclEntry(ACCESS, OTHER, WRITE)));
+    FileContext myfc = user.doAs(new PrivilegedExceptionAction<FileContext>() {
+      @Override
+      public FileContext run() throws IOException {
+        return FileContext.getFileContext(conf);
+      }
+    });
+
+    // Path to targetChild via symlink
+    myfc.access(link, FsAction.WRITE);
+    try {
+      myfc.access(link, FsAction.ALL);
+      fail("The access call should have failed.");
+    } catch (AccessControlException e) {
+      // expected
+    }
+
+    Path badPath = new Path(link, "bad");
+    try {
+      myfc.access(badPath, FsAction.READ);
+      fail("The access call should have failed");
+    } catch (FileNotFoundException e) {
+      // expected
+    }
+  }
 }