1 /*
2 * Copyright (c) 2008, 2009, 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.nio.file.*;
29 import static java.nio.file.StandardOpenOption.*;
30 import java.nio.ByteBuffer;
31 import java.nio.channels.FileChannel;
32 import java.io.IOException;
33 import java.util.*;
34 import sun.misc.Unsafe;
35
36 import static sun.nio.fs.WindowsNativeDispatcher.*;
37 import static sun.nio.fs.WindowsConstants.*;
38
39 /**
40 * Windows emulation of NamedAttributeView using Alternative Data Streams
41 */
42
43 class WindowsUserDefinedFileAttributeView
44 extends AbstractUserDefinedFileAttributeView
45 {
46 private static final Unsafe unsafe = Unsafe.getUnsafe();
47
48 // syntax to address named streams
49 private String join(String file, String name) {
50 if (name == null)
51 throw new NullPointerException("'name' is null");
52 return file + ":" + name;
53 }
54 private String join(WindowsPath file, String name) throws WindowsException {
55 return join(file.getPathForWin32Calls(), name);
56 }
57
58 private final WindowsPath file;
59 private final boolean followLinks;
60
61 WindowsUserDefinedFileAttributeView(WindowsPath file, boolean followLinks) {
62 this.file = file;
63 this.followLinks = followLinks;
64 }
65
66 // enumerates the file streams using FindFirstStream/FindNextStream APIs.
67 private List<String> listUsingStreamEnumeration() throws IOException {
68 List<String> list = new ArrayList<String>();
69 try {
70 FirstStream first = FindFirstStream(file.getPathForWin32Calls());
71 if (first != null) {
72 long handle = first.handle();
73 try {
74 // first stream is always ::$DATA for files
75 String name = first.name();
76 if (!name.equals("::$DATA")) {
77 String[] segs = name.split(":");
78 list.add(segs[1]);
79 }
80 while ((name = FindNextStream(handle)) != null) {
81 String[] segs = name.split(":");
82 list.add(segs[1]);
83 }
84 } finally {
85 FindClose(handle);
86 }
87 }
88 } catch (WindowsException x) {
89 x.rethrowAsIOException(file);
90 }
91 return Collections.unmodifiableList(list);
92 }
93
94 // enumerates the file streams by reading the stream headers using
95 // BackupRead
96 private List<String> listUsingBackupRead() throws IOException {
97 long handle = -1L;
98 try {
99 int flags = FILE_FLAG_BACKUP_SEMANTICS;
100 if (!followLinks && file.getFileSystem().supportsLinks())
101 flags |= FILE_FLAG_OPEN_REPARSE_POINT;
102
103 handle = CreateFile(file.getPathForWin32Calls(),
104 GENERIC_READ,
105 FILE_SHARE_READ, // no write as we depend on file size
106 OPEN_EXISTING,
107 flags);
108 } catch (WindowsException x) {
109 x.rethrowAsIOException(file);
110 }
111
112 // buffer to read stream header and stream name.
113 final int BUFFER_SIZE = 4096;
114 NativeBuffer buffer = null;
115
116 // result with names of alternative data streams
117 final List<String> list = new ArrayList<String>();
118
119 try {
120 buffer = NativeBuffers.getNativeBuffer(BUFFER_SIZE);
121 long address = buffer.address();
122
123 /**
124 * typedef struct _WIN32_STREAM_ID {
125 * DWORD dwStreamId;
126 * DWORD dwStreamAttributes;
127 * LARGE_INTEGER Size;
128 * DWORD dwStreamNameSize;
129 * WCHAR cStreamName[ANYSIZE_ARRAY];
130 * } WIN32_STREAM_ID;
131 */
132 final int SIZEOF_STREAM_HEADER = 20;
133 final int OFFSETOF_STREAM_ID = 0;
134 final int OFFSETOF_STREAM_SIZE = 8;
135 final int OFFSETOF_STREAM_NAME_SIZE = 16;
136
137 long context = 0L;
138 try {
139 for (;;) {
140 // read stream header
141 BackupResult result = BackupRead(handle, address,
142 SIZEOF_STREAM_HEADER, false, context);
143 context = result.context();
144 if (result.bytesTransferred() == 0)
145 break;
146
147 int streamId = unsafe.getInt(address + OFFSETOF_STREAM_ID);
148 long streamSize = unsafe.getLong(address + OFFSETOF_STREAM_SIZE);
149 int nameSize = unsafe.getInt(address + OFFSETOF_STREAM_NAME_SIZE);
150
151 // read stream name
152 if (nameSize > 0) {
153 result = BackupRead(handle, address, nameSize, false, context);
154 if (result.bytesTransferred() != nameSize)
155 break;
156 }
157
158 // check for alternative data stream
159 if (streamId == BACKUP_ALTERNATE_DATA) {
160 char[] nameAsArray = new char[nameSize/2];
161 unsafe.copyMemory(null, address, nameAsArray,
162 Unsafe.ARRAY_CHAR_BASE_OFFSET, nameSize);
163
164 String[] segs = new String(nameAsArray).split(":");
165 if (segs.length == 3)
166 list.add(segs[1]);
167 }
168
169 // sparse blocks not currently handled as documentation
170 // is not sufficient on how the spase block can be skipped.
171 if (streamId == BACKUP_SPARSE_BLOCK) {
172 throw new IOException("Spare blocks not handled");
173 }
174
175 // seek to end of stream
176 if (streamSize > 0L) {
177 BackupSeek(handle, streamSize, context);
178 }
179 }
180 } catch (WindowsException x) {
181 // failed to read or seek
182 throw new IOException(x.errorString());
183 } finally {
184 // release context
185 if (context != 0L) {
186 try {
187 BackupRead(handle, 0L, 0, true, context);
188 } catch (WindowsException ignore) { }
189 }
190 }
191 } finally {
192 if (buffer != null)
193 buffer.release();
194 CloseHandle(handle);
195 }
196 return Collections.unmodifiableList(list);
197 }
198
199 @Override
200 public List<String> list() throws IOException {
201 if (System.getSecurityManager() != null)
202 checkAccess(file.getPathForPermissionCheck(), true, false);
203 // use stream APIs on Windwos Server 2003 and newer
204 if (file.getFileSystem().supportsStreamEnumeration()) {
205 return listUsingStreamEnumeration();
206 } else {
207 return listUsingBackupRead();
208 }
209 }
210
211 @Override
212 public int size(String name) throws IOException {
213 if (System.getSecurityManager() != null)
214 checkAccess(file.getPathForPermissionCheck(), true, false);
215
216 // wrap with channel
217 FileChannel fc = null;
218 try {
219 Set<OpenOption> opts = new HashSet<OpenOption>();
220 opts.add(READ);
221 if (!followLinks)
222 opts.add(WindowsChannelFactory.OPEN_REPARSE_POINT);
223 fc = WindowsChannelFactory
224 .newFileChannel(join(file, name), null, opts, 0L);
225 } catch (WindowsException x) {
226 x.rethrowAsIOException(join(file.getPathForPermissionCheck(), name));
227 }
228 try {
229 long size = fc.size();
230 if (size > Integer.MAX_VALUE)
231 throw new ArithmeticException("Stream too large");
232 return (int)size;
233 } finally {
234 fc.close();
235 }
236 }
237
238 @Override
239 public int read(String name, ByteBuffer dst) throws IOException {
240 if (System.getSecurityManager() != null)
241 checkAccess(file.getPathForPermissionCheck(), true, false);
242
243 // wrap with channel
244 FileChannel fc = null;
245 try {
246 Set<OpenOption> opts = new HashSet<OpenOption>();
247 opts.add(READ);
248 if (!followLinks)
249 opts.add(WindowsChannelFactory.OPEN_REPARSE_POINT);
250 fc = WindowsChannelFactory
251 .newFileChannel(join(file, name), null, opts, 0L);
252 } catch (WindowsException x) {
253 x.rethrowAsIOException(join(file.getPathForPermissionCheck(), name));
254 }
255
256 // read to EOF (nothing we can do if I/O error occurs)
257 try {
258 if (fc.size() > dst.remaining())
259 throw new IOException("Stream too large");
260 int total = 0;
261 while (dst.hasRemaining()) {
262 int n = fc.read(dst);
263 if (n < 0)
264 break;
265 total += n;
266 }
267 return total;
268 } finally {
269 fc.close();
270 }
271 }
272
273 @Override
274 public int write(String name, ByteBuffer src) throws IOException {
275 if (System.getSecurityManager() != null)
276 checkAccess(file.getPathForPermissionCheck(), false, true);
277
278 /**
279 * Creating a named stream will cause the unnamed stream to be created
280 * if it doesn't already exist. To avoid this we open the unnamed stream
281 * for reading and hope it isn't deleted/moved while we create or
282 * replace the named stream. Opening the file without sharing options
283 * may cause sharing violations with other programs that are accessing
284 * the unnamed stream.
285 */
286 long handle = -1L;
287 try {
288 int flags = FILE_FLAG_BACKUP_SEMANTICS;
289 if (!followLinks)
290 flags |= FILE_FLAG_OPEN_REPARSE_POINT;
291
292 handle = CreateFile(file.getPathForWin32Calls(),
293 GENERIC_READ,
294 (FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE),
295 OPEN_EXISTING,
296 flags);
297 } catch (WindowsException x) {
298 x.rethrowAsIOException(file);
299 }
300 try {
301 Set<OpenOption> opts = new HashSet<OpenOption>();
302 if (!followLinks)
303 opts.add(WindowsChannelFactory.OPEN_REPARSE_POINT);
304 opts.add(CREATE);
305 opts.add(WRITE);
306 opts.add(StandardOpenOption.TRUNCATE_EXISTING);
307 FileChannel named = null;
308 try {
309 named = WindowsChannelFactory
310 .newFileChannel(join(file, name), null, opts, 0L);
311 } catch (WindowsException x) {
312 x.rethrowAsIOException(join(file.getPathForPermissionCheck(), name));
313 }
314 // write value (nothing we can do if I/O error occurs)
315 try {
316 int rem = src.remaining();
317 while (src.hasRemaining()) {
318 named.write(src);
319 }
320 return rem;
321 } finally {
322 named.close();
323 }
324 } finally {
325 CloseHandle(handle);
326 }
327 }
328
329 @Override
330 public void delete(String name) throws IOException {
331 if (System.getSecurityManager() != null)
332 checkAccess(file.getPathForPermissionCheck(), false, true);
333
334 String path = WindowsLinkSupport.getFinalPath(file, followLinks);
335 String toDelete = join(path, name);
336 try {
337 DeleteFile(toDelete);
338 } catch (WindowsException x) {
339 x.rethrowAsIOException(toDelete);
340 }
341 }
342 }