ojluni/src/main/java/sun/nio/fs/LinuxUserDefinedFileAttributeView.java - platform/libcore - Git at Google

 /*
  * Copyright (c) 2008, 2012, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Oracle in the LICENSE file that accompanied this code.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */

 package sun.nio.fs;

 import java.nio.file.*;
 import java.nio.ByteBuffer;
 import java.io.IOException;
 import java.util.*;
 import sun.misc.Unsafe;

 import static sun.nio.fs.UnixConstants.*;
 import static sun.nio.fs.LinuxNativeDispatcher.*;

 /**
  * Linux implementation of UserDefinedFileAttributeView using extended attributes.
  */

 class LinuxUserDefinedFileAttributeView
     extends AbstractUserDefinedFileAttributeView
 {
     private static final Unsafe unsafe = Unsafe.getUnsafe();

     // namespace for extended user attributes
     private static final String USER_NAMESPACE = "user.";

     // maximum bytes in extended attribute name (includes namespace)
     private static final int XATTR_NAME_MAX = 255;

     private byte[] nameAsBytes(UnixPath file, String name) throws IOException {
         if (name == null)
             throw new NullPointerException("'name' is null");
         name = USER_NAMESPACE + name;
         byte[] bytes = name.getBytes();
         if (bytes.length > XATTR_NAME_MAX) {
             throw new FileSystemException(file.getPathForExceptionMessage(),
                 null, "'" + name + "' is too big");
         }
         return bytes;
     }

     // Parses buffer as array of NULL-terminated C strings.
     private List<String> asList(long address, int size) {
         List<String> list = new ArrayList<>();
         int start = 0;
         int pos = 0;
         while (pos < size) {
             if (unsafe.getByte(address + pos) == 0) {
                 int len = pos - start;
                 byte[] value = new byte[len];
                 unsafe.copyMemory(null, address+start, value,
                     Unsafe.ARRAY_BYTE_BASE_OFFSET, len);
                 String s = new String(value);
                 if (s.startsWith(USER_NAMESPACE)) {
                     s = s.substring(USER_NAMESPACE.length());
                     list.add(s);
                 }
                 start = pos + 1;
             }
             pos++;
         }
         return list;
     }

     private final UnixPath file;
     private final boolean followLinks;

     LinuxUserDefinedFileAttributeView(UnixPath file, boolean followLinks) {
         this.file = file;
         this.followLinks = followLinks;
     }

     @Override
     public List<String> list() throws IOException  {
         if (System.getSecurityManager() != null)
             checkAccess(file.getPathForPermissionCheck(), true, false);

         int fd = file.openForAttributeAccess(followLinks);
         NativeBuffer buffer = null;
         try {
             int size = 1024;
             buffer = NativeBuffers.getNativeBuffer(size);
             for (;;) {
                 try {
                     int n = flistxattr(fd, buffer.address(), size);
                     List<String> list = asList(buffer.address(), n);
                     return Collections.unmodifiableList(list);
                 } catch (UnixException x) {
                     // allocate larger buffer if required
                     if (x.errno() == ERANGE && size < 32*1024) {
                         buffer.release();
                         size *= 2;
                         buffer = null;
                         buffer = NativeBuffers.getNativeBuffer(size);
                         continue;
                     }
                     throw new FileSystemException(file.getPathForExceptionMessage(),
                         null, "Unable to get list of extended attributes: " +
                         x.getMessage());
                 }
             }
         } finally {
             if (buffer != null)
                 buffer.release();
             close(fd);
         }
     }

     @Override
     public int size(String name) throws IOException  {
         if (System.getSecurityManager() != null)
             checkAccess(file.getPathForPermissionCheck(), true, false);

         int fd = file.openForAttributeAccess(followLinks);
         try {
             // fgetxattr returns size if called with size==0
             return fgetxattr(fd, nameAsBytes(file,name), 0L, 0);
         } catch (UnixException x) {
             throw new FileSystemException(file.getPathForExceptionMessage(),
                 null, "Unable to get size of extended attribute '" + name +
                 "': " + x.getMessage());
         } finally {
             close(fd);
         }
     }

     @Override
     public int read(String name, ByteBuffer dst) throws IOException {
         if (System.getSecurityManager() != null)
             checkAccess(file.getPathForPermissionCheck(), true, false);

         if (dst.isReadOnly())
             throw new IllegalArgumentException("Read-only buffer");
         int pos = dst.position();
         int lim = dst.limit();
         assert (pos <= lim);
         int rem = (pos <= lim ? lim - pos : 0);

         NativeBuffer nb;
         long address;
         if (dst instanceof sun.nio.ch.DirectBuffer) {
             nb = null;
             address = ((sun.nio.ch.DirectBuffer)dst).address() + pos;
         } else {
             // substitute with native buffer
             nb = NativeBuffers.getNativeBuffer(rem);
             address = nb.address();
         }

         int fd = file.openForAttributeAccess(followLinks);
         try {
             try {
                 int n = fgetxattr(fd, nameAsBytes(file,name), address, rem);

                 // if remaining is zero then fgetxattr returns the size
                 if (rem == 0) {
                     if (n > 0)
                         throw new UnixException(ERANGE);
                     return 0;
                 }

                 // copy from buffer into backing array if necessary
                 if (nb != null) {
                     int off = dst.arrayOffset() + pos + Unsafe.ARRAY_BYTE_BASE_OFFSET;
                     unsafe.copyMemory(null, address, dst.array(), off, n);
                 }
                 dst.position(pos + n);
                 return n;
             } catch (UnixException x) {
                 String msg = (x.errno() == ERANGE) ?
                     "Insufficient space in buffer" : x.getMessage();
                 throw new FileSystemException(file.getPathForExceptionMessage(),
                     null, "Error reading extended attribute '" + name + "': " + msg);
             } finally {
                 close(fd);
             }
         } finally {
             if (nb != null)
                 nb.release();
         }
     }

     @Override
     public int write(String name, ByteBuffer src) throws IOException {
         if (System.getSecurityManager() != null)
             checkAccess(file.getPathForPermissionCheck(), false, true);

         int pos = src.position();
         int lim = src.limit();
         assert (pos <= lim);
         int rem = (pos <= lim ? lim - pos : 0);

         NativeBuffer nb;
         long address;
         if (src instanceof sun.nio.ch.DirectBuffer) {
             nb = null;
             address = ((sun.nio.ch.DirectBuffer)src).address() + pos;
         } else {
             // substitute with native buffer
             nb = NativeBuffers.getNativeBuffer(rem);
             address = nb.address();

             if (src.hasArray()) {
                 // copy from backing array into buffer
                 int off = src.arrayOffset() + pos + Unsafe.ARRAY_BYTE_BASE_OFFSET;
                 unsafe.copyMemory(src.array(), off, null, address, rem);
             } else {
                 // backing array not accessible so transfer via temporary array
                 byte[] tmp = new byte[rem];
                 src.get(tmp);
                 src.position(pos);  // reset position as write may fail
                 unsafe.copyMemory(tmp, Unsafe.ARRAY_BYTE_BASE_OFFSET, null,
                     address, rem);
             }
         }

         int fd = file.openForAttributeAccess(followLinks);
         try {
             try {
                 fsetxattr(fd, nameAsBytes(file,name), address, rem);
                 src.position(pos + rem);
                 return rem;
             } catch (UnixException x) {
                 throw new FileSystemException(file.getPathForExceptionMessage(),
                     null, "Error writing extended attribute '" + name + "': " +
                     x.getMessage());
             } finally {
                 close(fd);
             }
         } finally {
             if (nb != null)
                 nb.release();
         }
     }

     @Override
     public void delete(String name) throws IOException {
         if (System.getSecurityManager() != null)
             checkAccess(file.getPathForPermissionCheck(), false, true);

         int fd = file.openForAttributeAccess(followLinks);
         try {
             fremovexattr(fd, nameAsBytes(file,name));
         } catch (UnixException x) {
             throw new FileSystemException(file.getPathForExceptionMessage(),
                 null, "Unable to delete extended attribute '" + name + "': " + x.getMessage());
         } finally {
             close(fd);
         }
     }

     /**
      * Used by copyTo/moveTo to copy extended attributes from source to target.
      *
      * @param   ofd
      *          file descriptor for source file
      * @param   nfd
      *          file descriptor for target file
      */
     static void copyExtendedAttributes(int ofd, int nfd) {
         NativeBuffer buffer = null;
         try {

             // call flistxattr to get list of extended attributes.
             int size = 1024;
             buffer = NativeBuffers.getNativeBuffer(size);
             for (;;) {
                 try {
                     size = flistxattr(ofd, buffer.address(), size);
                     break;
                 } catch (UnixException x) {
                     // allocate larger buffer if required
                     if (x.errno() == ERANGE && size < 32*1024) {
                         buffer.release();
                         size *= 2;
                         buffer = null;
                         buffer = NativeBuffers.getNativeBuffer(size);
                         continue;
                     }

                     // unable to get list of attributes
                     return;
                 }
             }

             // parse buffer as array of NULL-terminated C strings.
             long address = buffer.address();
             int start = 0;
             int pos = 0;
             while (pos < size) {
                 if (unsafe.getByte(address + pos) == 0) {
                     // extract attribute name and copy attribute to target.
                     // FIXME: We can avoid needless copying by using address+pos
                     // as the address of the name.
                     int len = pos - start;
                     byte[] name = new byte[len];
                     unsafe.copyMemory(null, address+start, name,
                         Unsafe.ARRAY_BYTE_BASE_OFFSET, len);
                     try {
                         copyExtendedAttribute(ofd, name, nfd);
                     } catch (UnixException ignore) {
                         // ignore
                     }
                     start = pos + 1;
                 }
                 pos++;
             }

         } finally {
             if (buffer != null)
                 buffer.release();
         }
     }

     private static void copyExtendedAttribute(int ofd, byte[] name, int nfd)
         throws UnixException
     {
         int size = fgetxattr(ofd, name, 0L, 0);
         NativeBuffer buffer = NativeBuffers.getNativeBuffer(size);
         try {
             long address = buffer.address();
             size = fgetxattr(ofd, name, address, size);
             fsetxattr(nfd, name, address, size);
         } finally {
             buffer.release();
         }
     }
 }
	/*
	* Copyright (c) 2008, 2012, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package sun.nio.fs;

	import java.nio.file.*;
	import java.nio.ByteBuffer;
	import java.io.IOException;
	import java.util.*;
	import sun.misc.Unsafe;

	import static sun.nio.fs.UnixConstants.*;
	import static sun.nio.fs.LinuxNativeDispatcher.*;

	/**
	* Linux implementation of UserDefinedFileAttributeView using extended attributes.
	*/

	class LinuxUserDefinedFileAttributeView
	extends AbstractUserDefinedFileAttributeView
	{
	private static final Unsafe unsafe = Unsafe.getUnsafe();

	// namespace for extended user attributes
	private static final String USER_NAMESPACE = "user.";

	// maximum bytes in extended attribute name (includes namespace)
	private static final int XATTR_NAME_MAX = 255;

	private byte[] nameAsBytes(UnixPath file, String name) throws IOException {
	if (name == null)
	throw new NullPointerException("'name' is null");
	name = USER_NAMESPACE + name;
	byte[] bytes = name.getBytes();
	if (bytes.length > XATTR_NAME_MAX) {
	throw new FileSystemException(file.getPathForExceptionMessage(),
	null, "'" + name + "' is too big");
	}
	return bytes;
	}

	// Parses buffer as array of NULL-terminated C strings.
	private List<String> asList(long address, int size) {
	List<String> list = new ArrayList<>();
	int start = 0;
	int pos = 0;
	while (pos < size) {
	if (unsafe.getByte(address + pos) == 0) {
	int len = pos - start;
	byte[] value = new byte[len];
	unsafe.copyMemory(null, address+start, value,
	Unsafe.ARRAY_BYTE_BASE_OFFSET, len);
	String s = new String(value);
	if (s.startsWith(USER_NAMESPACE)) {
	s = s.substring(USER_NAMESPACE.length());
	list.add(s);
	}
	start = pos + 1;
	}
	pos++;
	}
	return list;
	}

	private final UnixPath file;
	private final boolean followLinks;

	LinuxUserDefinedFileAttributeView(UnixPath file, boolean followLinks) {
	this.file = file;
	this.followLinks = followLinks;
	}

	@Override
	public List<String> list() throws IOException {
	if (System.getSecurityManager() != null)
	checkAccess(file.getPathForPermissionCheck(), true, false);

	int fd = file.openForAttributeAccess(followLinks);
	NativeBuffer buffer = null;
	try {
	int size = 1024;
	buffer = NativeBuffers.getNativeBuffer(size);
	for (;;) {
	try {
	int n = flistxattr(fd, buffer.address(), size);
	List<String> list = asList(buffer.address(), n);
	return Collections.unmodifiableList(list);
	} catch (UnixException x) {
	// allocate larger buffer if required
	if (x.errno() == ERANGE && size < 32*1024) {
	buffer.release();
	size *= 2;
	buffer = null;
	buffer = NativeBuffers.getNativeBuffer(size);
	continue;
	}
	throw new FileSystemException(file.getPathForExceptionMessage(),
	null, "Unable to get list of extended attributes: " +
	x.getMessage());
	}
	}
	} finally {
	if (buffer != null)
	buffer.release();
	close(fd);
	}
	}

	@Override
	public int size(String name) throws IOException {
	if (System.getSecurityManager() != null)
	checkAccess(file.getPathForPermissionCheck(), true, false);

	int fd = file.openForAttributeAccess(followLinks);
	try {
	// fgetxattr returns size if called with size==0
	return fgetxattr(fd, nameAsBytes(file,name), 0L, 0);
	} catch (UnixException x) {
	throw new FileSystemException(file.getPathForExceptionMessage(),
	null, "Unable to get size of extended attribute '" + name +
	"': " + x.getMessage());
	} finally {
	close(fd);
	}
	}

	@Override
	public int read(String name, ByteBuffer dst) throws IOException {
	if (System.getSecurityManager() != null)
	checkAccess(file.getPathForPermissionCheck(), true, false);

	if (dst.isReadOnly())
	throw new IllegalArgumentException("Read-only buffer");
	int pos = dst.position();
	int lim = dst.limit();
	assert (pos <= lim);
	int rem = (pos <= lim ? lim - pos : 0);

	NativeBuffer nb;
	long address;
	if (dst instanceof sun.nio.ch.DirectBuffer) {
	nb = null;
	address = ((sun.nio.ch.DirectBuffer)dst).address() + pos;
	} else {
	// substitute with native buffer
	nb = NativeBuffers.getNativeBuffer(rem);
	address = nb.address();
	}

	int fd = file.openForAttributeAccess(followLinks);
	try {
	try {
	int n = fgetxattr(fd, nameAsBytes(file,name), address, rem);

	// if remaining is zero then fgetxattr returns the size
	if (rem == 0) {
	if (n > 0)
	throw new UnixException(ERANGE);
	return 0;
	}

	// copy from buffer into backing array if necessary
	if (nb != null) {
	int off = dst.arrayOffset() + pos + Unsafe.ARRAY_BYTE_BASE_OFFSET;
	unsafe.copyMemory(null, address, dst.array(), off, n);
	}
	dst.position(pos + n);
	return n;
	} catch (UnixException x) {
	String msg = (x.errno() == ERANGE) ?
	"Insufficient space in buffer" : x.getMessage();
	throw new FileSystemException(file.getPathForExceptionMessage(),
	null, "Error reading extended attribute '" + name + "': " + msg);
	} finally {
	close(fd);
	}
	} finally {
	if (nb != null)
	nb.release();
	}
	}

	@Override
	public int write(String name, ByteBuffer src) throws IOException {
	if (System.getSecurityManager() != null)
	checkAccess(file.getPathForPermissionCheck(), false, true);

	int pos = src.position();
	int lim = src.limit();
	assert (pos <= lim);
	int rem = (pos <= lim ? lim - pos : 0);

	NativeBuffer nb;
	long address;
	if (src instanceof sun.nio.ch.DirectBuffer) {
	nb = null;
	address = ((sun.nio.ch.DirectBuffer)src).address() + pos;
	} else {
	// substitute with native buffer
	nb = NativeBuffers.getNativeBuffer(rem);
	address = nb.address();

	if (src.hasArray()) {
	// copy from backing array into buffer
	int off = src.arrayOffset() + pos + Unsafe.ARRAY_BYTE_BASE_OFFSET;
	unsafe.copyMemory(src.array(), off, null, address, rem);
	} else {
	// backing array not accessible so transfer via temporary array
	byte[] tmp = new byte[rem];
	src.get(tmp);
	src.position(pos); // reset position as write may fail
	unsafe.copyMemory(tmp, Unsafe.ARRAY_BYTE_BASE_OFFSET, null,
	address, rem);
	}
	}

	int fd = file.openForAttributeAccess(followLinks);
	try {
	try {
	fsetxattr(fd, nameAsBytes(file,name), address, rem);
	src.position(pos + rem);
	return rem;
	} catch (UnixException x) {
	throw new FileSystemException(file.getPathForExceptionMessage(),
	null, "Error writing extended attribute '" + name + "': " +
	x.getMessage());
	} finally {
	close(fd);
	}
	} finally {
	if (nb != null)
	nb.release();
	}
	}

	@Override
	public void delete(String name) throws IOException {
	if (System.getSecurityManager() != null)
	checkAccess(file.getPathForPermissionCheck(), false, true);

	int fd = file.openForAttributeAccess(followLinks);
	try {
	fremovexattr(fd, nameAsBytes(file,name));
	} catch (UnixException x) {
	throw new FileSystemException(file.getPathForExceptionMessage(),
	null, "Unable to delete extended attribute '" + name + "': " + x.getMessage());
	} finally {
	close(fd);
	}
	}

	/**
	* Used by copyTo/moveTo to copy extended attributes from source to target.
	*
	* @param ofd
	* file descriptor for source file
	* @param nfd
	* file descriptor for target file
	*/
	static void copyExtendedAttributes(int ofd, int nfd) {
	NativeBuffer buffer = null;
	try {

	// call flistxattr to get list of extended attributes.
	int size = 1024;
	buffer = NativeBuffers.getNativeBuffer(size);
	for (;;) {
	try {
	size = flistxattr(ofd, buffer.address(), size);
	break;
	} catch (UnixException x) {
	// allocate larger buffer if required
	if (x.errno() == ERANGE && size < 32*1024) {
	buffer.release();
	size *= 2;
	buffer = null;
	buffer = NativeBuffers.getNativeBuffer(size);
	continue;
	}

	// unable to get list of attributes
	return;
	}
	}

	// parse buffer as array of NULL-terminated C strings.
	long address = buffer.address();
	int start = 0;
	int pos = 0;
	while (pos < size) {
	if (unsafe.getByte(address + pos) == 0) {
	// extract attribute name and copy attribute to target.
	// FIXME: We can avoid needless copying by using address+pos
	// as the address of the name.
	int len = pos - start;
	byte[] name = new byte[len];
	unsafe.copyMemory(null, address+start, name,
	Unsafe.ARRAY_BYTE_BASE_OFFSET, len);
	try {
	copyExtendedAttribute(ofd, name, nfd);
	} catch (UnixException ignore) {
	// ignore
	}
	start = pos + 1;
	}
	pos++;
	}

	} finally {
	if (buffer != null)
	buffer.release();
	}
	}

	private static void copyExtendedAttribute(int ofd, byte[] name, int nfd)
	throws UnixException
	{
	int size = fgetxattr(ofd, name, 0L, 0);
	NativeBuffer buffer = NativeBuffers.getNativeBuffer(size);
	try {
	long address = buffer.address();
	size = fgetxattr(ofd, name, address, size);
	fsetxattr(nfd, name, address, size);
	} finally {
	buffer.release();
	}
	}
	}