/*
* Copyright (c) 2008, 2010, 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.attribute.*;
import java.util.*;
import java.io.IOException;
/**
* Linux implementation of FileStore
*/
class LinuxFileStore
extends UnixFileStore
{
// used when checking if extended attributes are enabled or not
private volatile boolean xattrChecked;
private volatile boolean xattrEnabled;
LinuxFileStore(UnixPath file) throws IOException {
super(file);
}
LinuxFileStore(UnixFileSystem fs, UnixMountEntry entry) throws IOException {
super(fs, entry);
}
/**
* Finds, and returns, the mount entry for the file system where the file
* resides.
*/
@Override
UnixMountEntry findMountEntry() throws IOException {
LinuxFileSystem fs = (LinuxFileSystem)file().getFileSystem();
// step 1: get realpath
UnixPath path = null;
try {
byte[] rp = UnixNativeDispatcher.realpath(file());
path = new UnixPath(fs, rp);
} catch (UnixException x) {
x.rethrowAsIOException(file());
}
// step 2: find mount point
UnixPath parent = path.getParent();
while (parent != null) {
UnixFileAttributes attrs = null;
try {
attrs = UnixFileAttributes.get(parent, true);
} catch (UnixException x) {
x.rethrowAsIOException(parent);
}
if (attrs.dev() != dev())
break;
path = parent;
parent = parent.getParent();
}
// step 3: lookup mounted file systems (use /proc/mounts to ensure we
// find the file system even when not in /etc/mtab)
byte[] dir = path.asByteArray();
for (UnixMountEntry entry: fs.getMountEntries("/proc/mounts")) {
if (Arrays.equals(dir, entry.dir()))
return entry;
}
throw new IOException("Mount point not found");
}
// returns true if extended attributes enabled on file system where given
// file resides, returns false if disabled or unable to determine.
private boolean isExtendedAttributesEnabled(UnixPath path) {
try {
int fd = path.openForAttributeAccess(false);
try {
// fgetxattr returns size if called with size==0
LinuxNativeDispatcher.fgetxattr(fd, "user.java".getBytes(), 0L, 0);
return true;
} catch (UnixException e) {
// attribute does not exist
if (e.errno() == UnixConstants.ENODATA)
return true;
} finally {
UnixNativeDispatcher.close(fd);
}
} catch (IOException ignore) {
// nothing we can do
}
return false;
}
@Override
public boolean supportsFileAttributeView(Class<? extends FileAttributeView> type) {
// support DosFileAttributeView and UserDefinedAttributeView if extended
// attributes enabled
if (type == DosFileAttributeView.class ||
type == UserDefinedFileAttributeView.class)
{
// lookup fstypes.properties
FeatureStatus status = checkIfFeaturePresent("user_xattr");
if (status == FeatureStatus.PRESENT)
return true;
if (status == FeatureStatus.NOT_PRESENT)
return false;
// if file system is mounted with user_xattr option then assume
// extended attributes are enabled
if ((entry().hasOption("user_xattr")))
return true;
// user_xattr option not present but we special-case ext3/4 as we
// know that extended attributes are not enabled by default.
if (entry().fstype().equals("ext3") || entry().fstype().equals("ext4"))
return false;
// not ext3/4 so probe mount point
if (!xattrChecked) {
UnixPath dir = new UnixPath(file().getFileSystem(), entry().dir());
xattrEnabled = isExtendedAttributesEnabled(dir);
xattrChecked = true;
}
return xattrEnabled;
}
return super.supportsFileAttributeView(type);
}
@Override
public boolean supportsFileAttributeView(String name) {
if (name.equals("dos"))
return supportsFileAttributeView(DosFileAttributeView.class);
if (name.equals("user"))
return supportsFileAttributeView(UserDefinedFileAttributeView.class);
return super.supportsFileAttributeView(name);
}
}