1 /*
2 * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package sun.nio.fs;
27
28 import java.io.IOException;
29 import java.nio.file.attribute.DosFileAttributeView;
30 import java.nio.file.attribute.FileAttributeView;
31 import java.nio.file.attribute.PosixFileAttributeView;
32 import java.nio.file.attribute.UserDefinedFileAttributeView;
33 import java.util.Arrays;
34 import java.util.List;
35 import java.util.regex.Pattern;
36
37 /**
38 * Linux implementation of FileStore
39 */
40
41 class LinuxFileStore
42 extends UnixFileStore
43 {
44 // used when checking if extended attributes are enabled or not
45 private volatile boolean xattrChecked;
46 private volatile boolean xattrEnabled;
47
48 LinuxFileStore(UnixPath file) throws IOException {
49 super(file);
50 }
51
52 LinuxFileStore(UnixFileSystem fs, UnixMountEntry entry) throws IOException {
53 super(fs, entry);
54 }
55
56 /**
57 * Finds, and returns, the mount entry for the file system where the file
58 * resides.
59 */
60 @Override
61 UnixMountEntry findMountEntry() throws IOException {
62 LinuxFileSystem fs = (LinuxFileSystem)file().getFileSystem();
63
64 // step 1: get realpath
65 UnixPath path = null;
66 try {
67 byte[] rp = UnixNativeDispatcher.realpath(file());
68 path = new UnixPath(fs, rp);
69 } catch (UnixException x) {
70 x.rethrowAsIOException(file());
71 }
72
73 // step 2: find mount point
74 List<UnixMountEntry> procMountsEntries =
75 fs.getMountEntries("/proc/mounts");
76 UnixPath parent = path.getParent();
77 while (parent != null) {
78 UnixFileAttributes attrs = null;
79 try {
80 attrs = UnixFileAttributes.get(parent, true);
81 } catch (UnixException x) {
82 x.rethrowAsIOException(parent);
83 }
84 if (attrs.dev() != dev()) {
85 // step 3: lookup mounted file systems (use /proc/mounts to
86 // ensure we find the file system even when not in /etc/mtab)
87 byte[] dir = path.asByteArray();
88 for (UnixMountEntry entry : procMountsEntries) {
89 if (Arrays.equals(dir, entry.dir()))
90 return entry;
91 }
92 }
93 path = parent;
94 parent = parent.getParent();
95 }
96
97 // step 3: lookup mounted file systems (use /proc/mounts to
98 // ensure we find the file system even when not in /etc/mtab)
99 byte[] dir = path.asByteArray();
100 for (UnixMountEntry entry : procMountsEntries) {
101 if (Arrays.equals(dir, entry.dir()))
102 return entry;
103 }
104
105 throw new IOException("Mount point not found");
106 }
107
108 // returns true if extended attributes enabled on file system where given
109 // file resides, returns false if disabled or unable to determine.
110 private boolean isExtendedAttributesEnabled(UnixPath path) {
111 int fd = -1;
112 try {
113 fd = path.openForAttributeAccess(false);
114
115 // fgetxattr returns size if called with size==0
116 byte[] name = Util.toBytes("user.java");
117 LinuxNativeDispatcher.fgetxattr(fd, name, 0L, 0);
118 return true;
119 } catch (UnixException e) {
120 // attribute does not exist
121 if (e.errno() == UnixConstants.ENODATA)
122 return true;
123 } finally {
124 UnixNativeDispatcher.close(fd);
125 }
126 return false;
127 }
128
129 // get kernel version as a three element array {major, minor, micro}
130 private static int[] getKernelVersion() {
131 Pattern pattern = Pattern.compile("\\D+");
132 String[] matches = pattern.split(System.getProperty("os.version"));
133 int[] majorMinorMicro = new int[3];
134 int length = Math.min(matches.length, majorMinorMicro.length);
135 for (int i = 0; i < length; i++) {
136 majorMinorMicro[i] = Integer.valueOf(matches[i]);
137 }
138 return majorMinorMicro;
139 }
140
141 @Override
142 public boolean supportsFileAttributeView(Class<? extends FileAttributeView> type) {
143 // support DosFileAttributeView and UserDefinedAttributeView if extended
144 // attributes enabled
145 if (type == DosFileAttributeView.class ||
146 type == UserDefinedFileAttributeView.class)
147 {
148 // lookup fstypes.properties
149 FeatureStatus status = checkIfFeaturePresent("user_xattr");
150 if (status == FeatureStatus.PRESENT)
151 return true;
152 if (status == FeatureStatus.NOT_PRESENT)
153 return false;
154
155 // if file system is mounted with user_xattr option then assume
156 // extended attributes are enabled
157 if ((entry().hasOption("user_xattr")))
158 return true;
159
160 // check for explicit disabling of extended attributes
161 if (entry().hasOption("nouser_xattr")) {
162 return false;
163 }
164
165 // user_{no}xattr options not present but we special-case ext3 as
166 // we know that extended attributes are not enabled by default.
167 if (entry().fstype().equals("ext3")) {
168 return false;
169 }
170
171 // user_xattr option not present but we special-case ext4 as we
172 // know that extended attributes are enabled by default for
173 // kernel version >= 2.6.39
174 if (entry().fstype().equals("ext4")) {
175 if (!xattrChecked) {
176 // check kernel version
177 int[] kernelVersion = getKernelVersion();
178 xattrEnabled = kernelVersion[0] > 2 ||
179 (kernelVersion[0] == 2 && kernelVersion[1] > 6) ||
180 (kernelVersion[0] == 2 && kernelVersion[1] == 6 &&
181 kernelVersion[2] >= 39);
182 xattrChecked = true;
183 }
184 return xattrEnabled;
185 }
186
187 // not ext3/4 so probe mount point
188 if (!xattrChecked) {
189 UnixPath dir = new UnixPath(file().getFileSystem(), entry().dir());
190 xattrEnabled = isExtendedAttributesEnabled(dir);
191 xattrChecked = true;
192 }
193 return xattrEnabled;
194 }
195 // POSIX attributes not supported on FAT
196 if (type == PosixFileAttributeView.class && entry().fstype().equals("vfat"))
197 return false;
198 return super.supportsFileAttributeView(type);
199 }
200
201 @Override
202 public boolean supportsFileAttributeView(String name) {
203 if (name.equals("dos"))
204 return supportsFileAttributeView(DosFileAttributeView.class);
205 if (name.equals("user"))
206 return supportsFileAttributeView(UserDefinedFileAttributeView.class);
207 return super.supportsFileAttributeView(name);
208 }
209 }