BsdFileStore.java

/*
 * Copyright (c) 2008, 2019, 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
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package sun.nio.fs;

import java.nio.file.attribute.FileAttributeView;
import java.nio.file.attribute.UserDefinedFileAttributeView;
import java.io.IOException;
import java.util.Arrays;
import sun.security.action.GetPropertyAction;

/**
 * Bsd implementation of FileStore
 */

class BsdFileStore
    extends UnixFileStore
{
    BsdFileStore(UnixPath file) throws IOException {
        super(file);
    }

    BsdFileStore(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 {
        UnixFileSystem fs = 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
        byte[] dir = null;
        try {
            dir = BsdNativeDispatcher.getmntonname(path);
        } catch (UnixException x) {
            x.rethrowAsIOException(path);
        }

        // step 3: lookup mounted file systems
        for (UnixMountEntry entry: fs.getMountEntries()) {
            if (Arrays.equals(dir, entry.dir()))
                return entry;
        }

        throw new IOException("Mount point not found in fstab");
    }

    @Override
    public boolean supportsFileAttributeView(Class<? extends FileAttributeView> type) {
        // support UserDefinedAttributeView if extended attributes enabled
        if (type == UserDefinedFileAttributeView.class) {
            // lookup fstypes.properties
            FeatureStatus status = checkIfFeaturePresent("user_xattr");
            if (status == FeatureStatus.PRESENT)
                return true;
            if (status == FeatureStatus.NOT_PRESENT)
                return false;

            // typical macOS file system types that are known to support xattr
            String fstype = entry().fstype();
            if ("hfs".equals(fstype))
                return true;
            if ("apfs".equals(fstype)) {
                // fgetxattr broken on APFS prior to 10.14
                return isOsVersionGte(10, 14);
            }

            // probe file system capabilities
            UnixPath dir = new UnixPath(file().getFileSystem(), entry().dir());
            return isExtendedAttributesEnabled(dir);
        }
        return super.supportsFileAttributeView(type);
    }

    @Override
    public boolean supportsFileAttributeView(String name) {
        if (name.equals("user"))
            return supportsFileAttributeView(UserDefinedFileAttributeView.class);
        return super.supportsFileAttributeView(name);
    }

    /**
     * Returns true if the OS major/minor version is greater than, or equal, to the
     * given major/minor version.
     */
    private static boolean isOsVersionGte(int requiredMajor, int requiredMinor) {
        String osVersion = GetPropertyAction.privilegedGetProperty("os.version");
        String[] vers = Util.split(osVersion, '.');
        int majorVersion = Integer.parseInt(vers[0]);
        int minorVersion = Integer.parseInt(vers[1]);
        return (majorVersion > requiredMajor)
                || (majorVersion == requiredMajor && minorVersion >= requiredMinor);
    }
}