Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2016 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package com.android.internal.os; |
| 18 | |
| 19 | import android.annotation.NonNull; |
| 20 | import android.annotation.Nullable; |
Daichi Hirono | 9fb0018 | 2016-11-08 14:12:17 +0900 | [diff] [blame] | 21 | import android.os.ProxyFileDescriptorCallback; |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 22 | import android.os.Handler; |
Daichi Hirono | 5c2688a | 2017-04-03 13:18:40 +0900 | [diff] [blame] | 23 | import android.os.Message; |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 24 | import android.os.ParcelFileDescriptor; |
| 25 | import android.system.ErrnoException; |
| 26 | import android.system.OsConstants; |
| 27 | import android.util.Log; |
| 28 | import android.util.SparseArray; |
| 29 | import com.android.internal.annotations.GuardedBy; |
| 30 | import com.android.internal.util.Preconditions; |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 31 | import java.util.HashMap; |
Daichi Hirono | 5c2688a | 2017-04-03 13:18:40 +0900 | [diff] [blame] | 32 | import java.util.LinkedList; |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 33 | import java.util.Map; |
Daichi Hirono | 9fb0018 | 2016-11-08 14:12:17 +0900 | [diff] [blame] | 34 | import java.util.concurrent.ThreadFactory; |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 35 | |
Daichi Hirono | 5c2688a | 2017-04-03 13:18:40 +0900 | [diff] [blame] | 36 | public class FuseAppLoop implements Handler.Callback { |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 37 | private static final String TAG = "FuseAppLoop"; |
| 38 | private static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG); |
| 39 | public static final int ROOT_INODE = 1; |
| 40 | private static final int MIN_INODE = 2; |
Daichi Hirono | 9fb0018 | 2016-11-08 14:12:17 +0900 | [diff] [blame] | 41 | private static final ThreadFactory sDefaultThreadFactory = new ThreadFactory() { |
| 42 | @Override |
| 43 | public Thread newThread(Runnable r) { |
| 44 | return new Thread(r, TAG); |
| 45 | } |
| 46 | }; |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 47 | private static final int FUSE_OK = 0; |
Daichi Hirono | 5c2688a | 2017-04-03 13:18:40 +0900 | [diff] [blame] | 48 | private static final int ARGS_POOL_SIZE = 50; |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 49 | |
| 50 | private final Object mLock = new Object(); |
Daichi Hirono | 9fb0018 | 2016-11-08 14:12:17 +0900 | [diff] [blame] | 51 | private final int mMountPointId; |
| 52 | private final Thread mThread; |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 53 | |
| 54 | @GuardedBy("mLock") |
| 55 | private final SparseArray<CallbackEntry> mCallbackMap = new SparseArray<>(); |
| 56 | |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 57 | @GuardedBy("mLock") |
| 58 | private final BytesMap mBytesMap = new BytesMap(); |
| 59 | |
Daichi Hirono | 5c2688a | 2017-04-03 13:18:40 +0900 | [diff] [blame] | 60 | @GuardedBy("mLock") |
| 61 | private final LinkedList<Args> mArgsPool = new LinkedList<>(); |
| 62 | |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 63 | /** |
| 64 | * Sequential number can be used as file name and inode in AppFuse. |
| 65 | * 0 is regarded as an error, 1 is mount point. So we start the number from 2. |
| 66 | */ |
| 67 | @GuardedBy("mLock") |
| 68 | private int mNextInode = MIN_INODE; |
| 69 | |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 70 | @GuardedBy("mLock") |
| 71 | private long mInstance; |
| 72 | |
| 73 | public FuseAppLoop( |
Daichi Hirono | 9fb0018 | 2016-11-08 14:12:17 +0900 | [diff] [blame] | 74 | int mountPointId, @NonNull ParcelFileDescriptor fd, @Nullable ThreadFactory factory) { |
| 75 | mMountPointId = mountPointId; |
Daichi Hirono | 9fb0018 | 2016-11-08 14:12:17 +0900 | [diff] [blame] | 76 | if (factory == null) { |
| 77 | factory = sDefaultThreadFactory; |
| 78 | } |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 79 | mInstance = native_new(fd.detachFd()); |
| 80 | mThread = factory.newThread(() -> { |
| 81 | native_start(mInstance); |
| 82 | synchronized (mLock) { |
| 83 | native_delete(mInstance); |
| 84 | mInstance = 0; |
| 85 | mBytesMap.clear(); |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 86 | } |
Daichi Hirono | 9fb0018 | 2016-11-08 14:12:17 +0900 | [diff] [blame] | 87 | }); |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 88 | mThread.start(); |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 89 | } |
| 90 | |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 91 | public int registerCallback(@NonNull ProxyFileDescriptorCallback callback, |
| 92 | @NonNull Handler handler) throws FuseUnavailableMountException { |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 93 | synchronized (mLock) { |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 94 | Preconditions.checkNotNull(callback); |
| 95 | Preconditions.checkNotNull(handler); |
| 96 | Preconditions.checkState( |
| 97 | mCallbackMap.size() < Integer.MAX_VALUE - MIN_INODE, "Too many opened files."); |
| 98 | Preconditions.checkArgument( |
| 99 | Thread.currentThread().getId() != handler.getLooper().getThread().getId(), |
| 100 | "Handler must be different from the current thread"); |
| 101 | if (mInstance == 0) { |
| 102 | throw new FuseUnavailableMountException(mMountPointId); |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 103 | } |
Daichi Hirono | 9fb0018 | 2016-11-08 14:12:17 +0900 | [diff] [blame] | 104 | int id; |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 105 | while (true) { |
| 106 | id = mNextInode; |
| 107 | mNextInode++; |
| 108 | if (mNextInode < 0) { |
| 109 | mNextInode = MIN_INODE; |
| 110 | } |
| 111 | if (mCallbackMap.get(id) == null) { |
| 112 | break; |
| 113 | } |
| 114 | } |
Daichi Hirono | 5c2688a | 2017-04-03 13:18:40 +0900 | [diff] [blame] | 115 | mCallbackMap.put(id, new CallbackEntry( |
| 116 | callback, new Handler(handler.getLooper(), this))); |
Daichi Hirono | 9fb0018 | 2016-11-08 14:12:17 +0900 | [diff] [blame] | 117 | return id; |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 118 | } |
| 119 | } |
| 120 | |
Daichi Hirono | 9fb0018 | 2016-11-08 14:12:17 +0900 | [diff] [blame] | 121 | public void unregisterCallback(int id) { |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 122 | synchronized (mLock) { |
| 123 | mCallbackMap.remove(id); |
| 124 | } |
Daichi Hirono | 9fb0018 | 2016-11-08 14:12:17 +0900 | [diff] [blame] | 125 | } |
| 126 | |
| 127 | public int getMountPointId() { |
| 128 | return mMountPointId; |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 129 | } |
| 130 | |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 131 | // Defined in fuse.h |
| 132 | private static final int FUSE_LOOKUP = 1; |
| 133 | private static final int FUSE_GETATTR = 3; |
| 134 | private static final int FUSE_OPEN = 14; |
| 135 | private static final int FUSE_READ = 15; |
| 136 | private static final int FUSE_WRITE = 16; |
| 137 | private static final int FUSE_RELEASE = 18; |
| 138 | private static final int FUSE_FSYNC = 20; |
| 139 | |
| 140 | // Defined in FuseBuffer.h |
| 141 | private static final int FUSE_MAX_WRITE = 256 * 1024; |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 142 | |
Daichi Hirono | 5c2688a | 2017-04-03 13:18:40 +0900 | [diff] [blame] | 143 | @Override |
| 144 | public boolean handleMessage(Message msg) { |
| 145 | final Args args = (Args) msg.obj; |
| 146 | final CallbackEntry entry = args.entry; |
| 147 | final long inode = args.inode; |
| 148 | final long unique = args.unique; |
| 149 | final int size = args.size; |
| 150 | final long offset = args.offset; |
| 151 | final byte[] data = args.data; |
| 152 | |
| 153 | try { |
| 154 | switch (msg.what) { |
| 155 | case FUSE_LOOKUP: { |
| 156 | final long fileSize = entry.callback.onGetSize(); |
| 157 | synchronized (mLock) { |
| 158 | if (mInstance != 0) { |
| 159 | native_replyLookup(mInstance, unique, inode, fileSize); |
| 160 | } |
| 161 | recycleLocked(args); |
| 162 | } |
| 163 | break; |
| 164 | } |
| 165 | case FUSE_GETATTR: { |
| 166 | final long fileSize = entry.callback.onGetSize(); |
| 167 | synchronized (mLock) { |
| 168 | if (mInstance != 0) { |
| 169 | native_replyGetAttr(mInstance, unique, inode, fileSize); |
| 170 | } |
| 171 | recycleLocked(args); |
| 172 | } |
| 173 | break; |
| 174 | } |
| 175 | case FUSE_READ: |
| 176 | final int readSize = entry.callback.onRead( |
| 177 | offset, size, data); |
| 178 | synchronized (mLock) { |
| 179 | if (mInstance != 0) { |
| 180 | native_replyRead(mInstance, unique, readSize, data); |
| 181 | } |
| 182 | recycleLocked(args); |
| 183 | } |
| 184 | break; |
| 185 | case FUSE_WRITE: |
| 186 | final int writeSize = entry.callback.onWrite(offset, size, data); |
| 187 | synchronized (mLock) { |
| 188 | if (mInstance != 0) { |
| 189 | native_replyWrite(mInstance, unique, writeSize); |
| 190 | } |
| 191 | recycleLocked(args); |
| 192 | } |
| 193 | break; |
| 194 | case FUSE_FSYNC: |
| 195 | entry.callback.onFsync(); |
| 196 | synchronized (mLock) { |
| 197 | if (mInstance != 0) { |
| 198 | native_replySimple(mInstance, unique, FUSE_OK); |
| 199 | } |
| 200 | recycleLocked(args); |
| 201 | } |
| 202 | break; |
| 203 | case FUSE_RELEASE: |
| 204 | entry.callback.onRelease(); |
| 205 | synchronized (mLock) { |
| 206 | if (mInstance != 0) { |
| 207 | native_replySimple(mInstance, unique, FUSE_OK); |
| 208 | } |
| 209 | mBytesMap.stopUsing(entry.getThreadId()); |
| 210 | recycleLocked(args); |
| 211 | } |
| 212 | break; |
| 213 | default: |
| 214 | throw new IllegalArgumentException("Unknown FUSE command: " + msg.what); |
| 215 | } |
| 216 | } catch (Exception error) { |
| 217 | synchronized (mLock) { |
| 218 | Log.e(TAG, "", error); |
| 219 | replySimpleLocked(unique, getError(error)); |
| 220 | recycleLocked(args); |
| 221 | } |
| 222 | } |
| 223 | |
| 224 | return true; |
| 225 | } |
| 226 | |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 227 | // Called by JNI. |
| 228 | @SuppressWarnings("unused") |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 229 | private void onCommand(int command, long unique, long inode, long offset, int size, |
| 230 | byte[] data) { |
Daichi Hirono | 5c2688a | 2017-04-03 13:18:40 +0900 | [diff] [blame] | 231 | synchronized (mLock) { |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 232 | try { |
Daichi Hirono | 5c2688a | 2017-04-03 13:18:40 +0900 | [diff] [blame] | 233 | final Args args; |
| 234 | if (mArgsPool.size() == 0) { |
| 235 | args = new Args(); |
| 236 | } else { |
| 237 | args = mArgsPool.pop(); |
| 238 | } |
| 239 | args.unique = unique; |
| 240 | args.inode = inode; |
| 241 | args.offset = offset; |
| 242 | args.size = size; |
| 243 | args.data = data; |
| 244 | args.entry = getCallbackEntryOrThrowLocked(inode); |
| 245 | if (!args.entry.handler.sendMessage( |
| 246 | Message.obtain(args.entry.handler, command, 0, 0, args))) { |
| 247 | throw new ErrnoException("onCommand", OsConstants.EBADF); |
| 248 | } |
| 249 | } catch (Exception error) { |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 250 | replySimpleLocked(unique, getError(error)); |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 251 | } |
| 252 | } |
| 253 | } |
| 254 | |
| 255 | // Called by JNI. |
| 256 | @SuppressWarnings("unused") |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 257 | private byte[] onOpen(long unique, long inode) { |
| 258 | synchronized (mLock) { |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 259 | try { |
| 260 | final CallbackEntry entry = getCallbackEntryOrThrowLocked(inode); |
| 261 | if (entry.opened) { |
| 262 | throw new ErrnoException("onOpen", OsConstants.EMFILE); |
| 263 | } |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 264 | if (mInstance != 0) { |
| 265 | native_replyOpen(mInstance, unique, /* fh */ inode); |
| 266 | entry.opened = true; |
| 267 | return mBytesMap.startUsing(entry.getThreadId()); |
| 268 | } |
| 269 | } catch (ErrnoException error) { |
| 270 | replySimpleLocked(unique, getError(error)); |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 271 | } |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 272 | return null; |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 273 | } |
| 274 | } |
| 275 | |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 276 | private static int getError(@NonNull Exception error) { |
| 277 | if (error instanceof ErrnoException) { |
| 278 | final int errno = ((ErrnoException) error).errno; |
| 279 | if (errno != OsConstants.ENOSYS) { |
| 280 | return -errno; |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 281 | } |
| 282 | } |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 283 | return -OsConstants.EBADF; |
| 284 | } |
| 285 | |
Andreas Gampe | 3f24e69 | 2018-02-05 13:24:28 -0800 | [diff] [blame] | 286 | @GuardedBy("mLock") |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 287 | private CallbackEntry getCallbackEntryOrThrowLocked(long inode) throws ErrnoException { |
| 288 | final CallbackEntry entry = mCallbackMap.get(checkInode(inode)); |
| 289 | if (entry == null) { |
| 290 | throw new ErrnoException("getCallbackEntryOrThrowLocked", OsConstants.ENOENT); |
| 291 | } |
| 292 | return entry; |
| 293 | } |
| 294 | |
Andreas Gampe | 3f24e69 | 2018-02-05 13:24:28 -0800 | [diff] [blame] | 295 | @GuardedBy("mLock") |
Daichi Hirono | 5c2688a | 2017-04-03 13:18:40 +0900 | [diff] [blame] | 296 | private void recycleLocked(Args args) { |
| 297 | if (mArgsPool.size() < ARGS_POOL_SIZE) { |
| 298 | mArgsPool.add(args); |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 299 | } |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 300 | } |
| 301 | |
Andreas Gampe | 3f24e69 | 2018-02-05 13:24:28 -0800 | [diff] [blame] | 302 | @GuardedBy("mLock") |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 303 | private void replySimpleLocked(long unique, int result) { |
| 304 | if (mInstance != 0) { |
| 305 | native_replySimple(mInstance, unique, result); |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 306 | } |
| 307 | } |
| 308 | |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 309 | native long native_new(int fd); |
| 310 | native void native_delete(long ptr); |
| 311 | native void native_start(long ptr); |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 312 | |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 313 | native void native_replySimple(long ptr, long unique, int result); |
| 314 | native void native_replyOpen(long ptr, long unique, long fh); |
| 315 | native void native_replyLookup(long ptr, long unique, long inode, long size); |
| 316 | native void native_replyGetAttr(long ptr, long unique, long inode, long size); |
| 317 | native void native_replyWrite(long ptr, long unique, int size); |
| 318 | native void native_replyRead(long ptr, long unique, int size, byte[] bytes); |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 319 | |
| 320 | private static int checkInode(long inode) { |
| 321 | Preconditions.checkArgumentInRange(inode, MIN_INODE, Integer.MAX_VALUE, "checkInode"); |
| 322 | return (int) inode; |
| 323 | } |
| 324 | |
| 325 | public static class UnmountedException extends Exception {} |
| 326 | |
| 327 | private static class CallbackEntry { |
Daichi Hirono | 9fb0018 | 2016-11-08 14:12:17 +0900 | [diff] [blame] | 328 | final ProxyFileDescriptorCallback callback; |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 329 | final Handler handler; |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 330 | boolean opened; |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 331 | |
| 332 | CallbackEntry(ProxyFileDescriptorCallback callback, Handler handler) { |
| 333 | this.callback = Preconditions.checkNotNull(callback); |
| 334 | this.handler = Preconditions.checkNotNull(handler); |
| 335 | } |
| 336 | |
| 337 | long getThreadId() { |
| 338 | return handler.getLooper().getThread().getId(); |
| 339 | } |
Daichi Hirono | 4f15606 | 2017-02-08 16:20:20 +0900 | [diff] [blame] | 340 | } |
| 341 | |
| 342 | /** |
| 343 | * Entry for bytes map. |
| 344 | */ |
| 345 | private static class BytesMapEntry { |
| 346 | int counter = 0; |
| 347 | byte[] bytes = new byte[FUSE_MAX_WRITE]; |
| 348 | } |
| 349 | |
| 350 | /** |
| 351 | * Map between Thread ID and byte buffer. |
| 352 | */ |
| 353 | private static class BytesMap { |
| 354 | final Map<Long, BytesMapEntry> mEntries = new HashMap<>(); |
| 355 | |
| 356 | byte[] startUsing(long threadId) { |
| 357 | BytesMapEntry entry = mEntries.get(threadId); |
| 358 | if (entry == null) { |
| 359 | entry = new BytesMapEntry(); |
| 360 | mEntries.put(threadId, entry); |
| 361 | } |
| 362 | entry.counter++; |
| 363 | return entry.bytes; |
| 364 | } |
| 365 | |
| 366 | void stopUsing(long threadId) { |
| 367 | final BytesMapEntry entry = mEntries.get(threadId); |
| 368 | Preconditions.checkNotNull(entry); |
| 369 | entry.counter--; |
| 370 | if (entry.counter <= 0) { |
| 371 | mEntries.remove(threadId); |
| 372 | } |
| 373 | } |
| 374 | |
| 375 | void clear() { |
| 376 | mEntries.clear(); |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 377 | } |
| 378 | } |
Daichi Hirono | 5c2688a | 2017-04-03 13:18:40 +0900 | [diff] [blame] | 379 | |
| 380 | private static class Args { |
| 381 | long unique; |
| 382 | long inode; |
| 383 | long offset; |
| 384 | int size; |
| 385 | byte[] data; |
| 386 | CallbackEntry entry; |
| 387 | } |
Daichi Hirono | 878e86f | 2016-10-31 09:33:30 +0900 | [diff] [blame] | 388 | } |