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/* * Copyright (C) 2006 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package android.os; import static android.system.OsConstants.AF_UNIX; import static android.system.OsConstants.O_APPEND; import static android.system.OsConstants.O_CREAT; import static android.system.OsConstants.O_RDONLY; import static android.system.OsConstants.O_RDWR; import static android.system.OsConstants.O_TRUNC; import static android.system.OsConstants.O_WRONLY; import static android.system.OsConstants.SEEK_SET; import static android.system.OsConstants.SOCK_SEQPACKET; import static android.system.OsConstants.SOCK_STREAM; import static android.system.OsConstants.S_IROTH; import static android.system.OsConstants.S_IRWXG; import static android.system.OsConstants.S_IRWXU; import static android.system.OsConstants.S_ISLNK; import static android.system.OsConstants.S_ISREG; import static android.system.OsConstants.S_IWOTH; import android.annotation.UnsupportedAppUsage; import android.content.BroadcastReceiver; import android.content.ContentProvider; import android.os.MessageQueue.OnFileDescriptorEventListener; import android.system.ErrnoException; import android.system.Os; import android.system.OsConstants; import android.system.StructStat; import android.util.Log; import dalvik.system.CloseGuard; import libcore.io.IoUtils; import libcore.io.Memory; import java.io.Closeable; import java.io.File; import java.io.FileDescriptor; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InterruptedIOException; import java.io.UncheckedIOException; import java.net.DatagramSocket; import java.net.Socket; import java.nio.ByteOrder; /** * The FileDescriptor returned by {@link Parcel#readFileDescriptor}, allowing * you to close it when done with it. */ public class ParcelFileDescriptor implements Parcelable, Closeable { private static final String TAG = "ParcelFileDescriptor"; private final FileDescriptor mFd; /** * Optional socket used to communicate close events, status at close, and * detect remote process crashes. */ private FileDescriptor mCommFd; /** * Wrapped {@link ParcelFileDescriptor}, if any. Used to avoid * double-closing {@link #mFd}. */ private final ParcelFileDescriptor mWrapped; /** * Maximum {@link #mStatusBuf} size; longer status messages will be * truncated. */ private static final int MAX_STATUS = 1024; /** * Temporary buffer used by {@link #readCommStatus(FileDescriptor, byte[])}, * allocated on-demand. */ private byte[] mStatusBuf; /** * Status read by {@link #checkError()}, or null if not read yet. */ private Status mStatus; private volatile boolean mClosed; private final CloseGuard mGuard = CloseGuard.get(); /** * For use with {@link #open}: if {@link #MODE_CREATE} has been supplied and * this file doesn't already exist, then create the file with permissions * such that any application can read it. * * @deprecated Creating world-readable files is very dangerous, and likely * to cause security holes in applications. It is strongly * discouraged; instead, applications should use more formal * mechanism for interactions such as {@link ContentProvider}, * {@link BroadcastReceiver}, and {@link android.app.Service}. * There are no guarantees that this access mode will remain on * a file, such as when it goes through a backup and restore. */ @Deprecated public static final int MODE_WORLD_READABLE = 0x00000001; /** * For use with {@link #open}: if {@link #MODE_CREATE} has been supplied and * this file doesn't already exist, then create the file with permissions * such that any application can write it. * * @deprecated Creating world-writable files is very dangerous, and likely * to cause security holes in applications. It is strongly * discouraged; instead, applications should use more formal * mechanism for interactions such as {@link ContentProvider}, * {@link BroadcastReceiver}, and {@link android.app.Service}. * There are no guarantees that this access mode will remain on * a file, such as when it goes through a backup and restore. */ @Deprecated public static final int MODE_WORLD_WRITEABLE = 0x00000002; /** * For use with {@link #open}: open the file with read-only access. */ public static final int MODE_READ_ONLY = 0x10000000; /** * For use with {@link #open}: open the file with write-only access. */ public static final int MODE_WRITE_ONLY = 0x20000000; /** * For use with {@link #open}: open the file with read and write access. */ public static final int MODE_READ_WRITE = 0x30000000; /** * For use with {@link #open}: create the file if it doesn't already exist. */ public static final int MODE_CREATE = 0x08000000; /** * For use with {@link #open}: erase contents of file when opening. */ public static final int MODE_TRUNCATE = 0x04000000; /** * For use with {@link #open}: append to end of file while writing. */ public static final int MODE_APPEND = 0x02000000; /** * Create a new ParcelFileDescriptor wrapped around another descriptor. By * default all method calls are delegated to the wrapped descriptor. */ public ParcelFileDescriptor(ParcelFileDescriptor wrapped) { // We keep a strong reference to the wrapped PFD, and rely on its // finalizer to trigger CloseGuard. All calls are delegated to wrapper. mWrapped = wrapped; mFd = null; mCommFd = null; mClosed = true; } /** {@hide} */ @UnsupportedAppUsage public ParcelFileDescriptor(FileDescriptor fd) { this(fd, null); } /** {@hide} */ public ParcelFileDescriptor(FileDescriptor fd, FileDescriptor commChannel) { if (fd == null) { throw new NullPointerException("FileDescriptor must not be null"); } mWrapped = null; mFd = fd; IoUtils.setFdOwner(mFd, this); mCommFd = commChannel; if (mCommFd != null) { IoUtils.setFdOwner(mCommFd, this); } mGuard.open("close"); } /** * Create a new ParcelFileDescriptor accessing a given file. * * @param file The file to be opened. * @param mode The desired access mode, must be one of * {@link #MODE_READ_ONLY}, {@link #MODE_WRITE_ONLY}, or * {@link #MODE_READ_WRITE}; may also be any combination of * {@link #MODE_CREATE}, {@link #MODE_TRUNCATE}, * {@link #MODE_WORLD_READABLE}, and * {@link #MODE_WORLD_WRITEABLE}. * @return a new ParcelFileDescriptor pointing to the given file. * @throws FileNotFoundException if the given file does not exist or can not * be opened with the requested mode. * @see #parseMode(String) */ public static ParcelFileDescriptor open(File file, int mode) throws FileNotFoundException { final FileDescriptor fd = openInternal(file, mode); if (fd == null) return null; return new ParcelFileDescriptor(fd); } /** * Create a new ParcelFileDescriptor accessing a given file. * * @param file The file to be opened. * @param mode The desired access mode, must be one of * {@link #MODE_READ_ONLY}, {@link #MODE_WRITE_ONLY}, or * {@link #MODE_READ_WRITE}; may also be any combination of * {@link #MODE_CREATE}, {@link #MODE_TRUNCATE}, * {@link #MODE_WORLD_READABLE}, and * {@link #MODE_WORLD_WRITEABLE}. * @param handler to call listener from; must not be null. * @param listener to be invoked when the returned descriptor has been * closed; must not be null. * @return a new ParcelFileDescriptor pointing to the given file. * @throws FileNotFoundException if the given file does not exist or can not * be opened with the requested mode. * @see #parseMode(String) */ public static ParcelFileDescriptor open(File file, int mode, Handler handler, final OnCloseListener listener) throws IOException { if (handler == null) { throw new IllegalArgumentException("Handler must not be null"); } if (listener == null) { throw new IllegalArgumentException("Listener must not be null"); } final FileDescriptor fd = openInternal(file, mode); if (fd == null) return null; return fromFd(fd, handler, listener); } /** {@hide} */ public static ParcelFileDescriptor fromFd(FileDescriptor fd, Handler handler, final OnCloseListener listener) throws IOException { if (handler == null) { throw new IllegalArgumentException("Handler must not be null"); } if (listener == null) { throw new IllegalArgumentException("Listener must not be null"); } final FileDescriptor[] comm = createCommSocketPair(); final ParcelFileDescriptor pfd = new ParcelFileDescriptor(fd, comm[0]); final MessageQueue queue = handler.getLooper().getQueue(); queue.addOnFileDescriptorEventListener(comm[1], OnFileDescriptorEventListener.EVENT_INPUT, new OnFileDescriptorEventListener() { @Override public int onFileDescriptorEvents(FileDescriptor fd, int events) { Status status = null; if ((events & OnFileDescriptorEventListener.EVENT_INPUT) != 0) { final byte[] buf = new byte[MAX_STATUS]; status = readCommStatus(fd, buf); } else if ((events & OnFileDescriptorEventListener.EVENT_ERROR) != 0) { status = new Status(Status.DEAD); } if (status != null) { queue.removeOnFileDescriptorEventListener(fd); IoUtils.closeQuietly(fd); listener.onClose(status.asIOException()); return 0; } return EVENT_INPUT; } }); return pfd; } private static FileDescriptor openInternal(File file, int mode) throws FileNotFoundException { if ((mode & MODE_READ_WRITE) == 0) { throw new IllegalArgumentException("Must specify MODE_READ_ONLY, MODE_WRITE_ONLY, or MODE_READ_WRITE"); } int flags = 0; switch (mode & MODE_READ_WRITE) { case 0: case MODE_READ_ONLY: flags = O_RDONLY; break; case MODE_WRITE_ONLY: flags = O_WRONLY; break; case MODE_READ_WRITE: flags = O_RDWR; break; } if ((mode & MODE_CREATE) != 0) flags |= O_CREAT; if ((mode & MODE_TRUNCATE) != 0) flags |= O_TRUNC; if ((mode & MODE_APPEND) != 0) flags |= O_APPEND; int realMode = S_IRWXU | S_IRWXG; if ((mode & MODE_WORLD_READABLE) != 0) realMode |= S_IROTH; if ((mode & MODE_WORLD_WRITEABLE) != 0) realMode |= S_IWOTH; final String path = file.getPath(); try { return Os.open(path, flags, realMode); } catch (ErrnoException e) { throw new FileNotFoundException(e.getMessage()); } } /** * Create a new ParcelFileDescriptor that is a dup of an existing * FileDescriptor. This obeys standard POSIX semantics, where the * new file descriptor shared state such as file position with the * original file descriptor. */ public static ParcelFileDescriptor dup(FileDescriptor orig) throws IOException { try { final FileDescriptor fd = Os.dup(orig); return new ParcelFileDescriptor(fd); } catch (ErrnoException e) { throw e.rethrowAsIOException(); } } /** * Create a new ParcelFileDescriptor that is a dup of the existing * FileDescriptor. This obeys standard POSIX semantics, where the * new file descriptor shared state such as file position with the * original file descriptor. */ public ParcelFileDescriptor dup() throws IOException { if (mWrapped != null) { return mWrapped.dup(); } else { return dup(getFileDescriptor()); } } /** * Create a new ParcelFileDescriptor from a raw native fd. The new * ParcelFileDescriptor holds a dup of the original fd passed in here, * so you must still close that fd as well as the new ParcelFileDescriptor. * * @param fd The native fd that the ParcelFileDescriptor should dup. * * @return Returns a new ParcelFileDescriptor holding a FileDescriptor * for a dup of the given fd. */ public static ParcelFileDescriptor fromFd(int fd) throws IOException { final FileDescriptor original = new FileDescriptor(); original.setInt$(fd); try { final FileDescriptor dup = Os.dup(original); return new ParcelFileDescriptor(dup); } catch (ErrnoException e) { throw e.rethrowAsIOException(); } } /** * Take ownership of a raw native fd in to a new ParcelFileDescriptor. * The returned ParcelFileDescriptor now owns the given fd, and will be * responsible for closing it. * <p> * <strong>WARNING:</strong> You must not close the fd yourself after * this call, and ownership of the file descriptor must have been * released prior to the call to this function. * * @param fd The native fd that the ParcelFileDescriptor should adopt. * * @return Returns a new ParcelFileDescriptor holding a FileDescriptor * for the given fd. */ public static ParcelFileDescriptor adoptFd(int fd) { final FileDescriptor fdesc = new FileDescriptor(); fdesc.setInt$(fd); return new ParcelFileDescriptor(fdesc); } /** * Create a new ParcelFileDescriptor from the specified Socket. The new * ParcelFileDescriptor holds a dup of the original FileDescriptor in * the Socket, so you must still close the Socket as well as the new * ParcelFileDescriptor. * <p> * <strong>WARNING:</strong> Prior to API level 29, this function would not * actually dup the Socket's FileDescriptor, and would take a * reference to the its internal FileDescriptor instead. If the Socket * gets garbage collected before the ParcelFileDescriptor, this may * lead to the ParcelFileDescriptor being unexpectedly closed. To avoid * this, the following pattern can be used: * <pre>{@code * ParcelFileDescriptor pfd = ParcelFileDescriptor.fromSocket(socket).dup(); * }</pre> * * @param socket The Socket whose FileDescriptor is used to create * a new ParcelFileDescriptor. * * @return A new ParcelFileDescriptor with a duped copy of the * FileDescriptor of the specified Socket. * * @throws UncheckedIOException if {@link #dup(FileDescriptor)} throws IOException. */ public static ParcelFileDescriptor fromSocket(Socket socket) { FileDescriptor fd = socket.getFileDescriptor$(); try { return fd != null ? ParcelFileDescriptor.dup(fd) : null; } catch (IOException e) { throw new UncheckedIOException(e); } } /** * Create a new ParcelFileDescriptor from the specified DatagramSocket. The * new ParcelFileDescriptor holds a dup of the original FileDescriptor in * the DatagramSocket, so you must still close the DatagramSocket as well * as the new ParcelFileDescriptor. * <p> * <strong>WARNING:</strong> Prior to API level 29, this function would not * actually dup the DatagramSocket's FileDescriptor, and would take a * reference to the its internal FileDescriptor instead. If the DatagramSocket * gets garbage collected before the ParcelFileDescriptor, this may * lead to the ParcelFileDescriptor being unexpectedly closed. To avoid * this, the following pattern can be used: * <pre>{@code * ParcelFileDescriptor pfd = ParcelFileDescriptor.fromDatagramSocket(socket).dup(); * }</pre> * * @param datagramSocket The DatagramSocket whose FileDescriptor is used * to create a new ParcelFileDescriptor. * * @return A new ParcelFileDescriptor with a duped copy of the * FileDescriptor of the specified Socket. * * @throws UncheckedIOException if {@link #dup(FileDescriptor)} throws IOException. */ public static ParcelFileDescriptor fromDatagramSocket(DatagramSocket datagramSocket) { FileDescriptor fd = datagramSocket.getFileDescriptor$(); try { return fd != null ? ParcelFileDescriptor.dup(fd) : null; } catch (IOException e) { throw new UncheckedIOException(e); } } /** * Create two ParcelFileDescriptors structured as a data pipe. The first * ParcelFileDescriptor in the returned array is the read side; the second * is the write side. */ public static ParcelFileDescriptor[] createPipe() throws IOException { try { final FileDescriptor[] fds = Os.pipe(); return new ParcelFileDescriptor[] { new ParcelFileDescriptor(fds[0]), new ParcelFileDescriptor(fds[1]) }; } catch (ErrnoException e) { throw e.rethrowAsIOException(); } } /** * Create two ParcelFileDescriptors structured as a data pipe. The first * ParcelFileDescriptor in the returned array is the read side; the second * is the write side. * <p> * The write end has the ability to deliver an error message through * {@link #closeWithError(String)} which can be handled by the read end * calling {@link #checkError()}, usually after detecting an EOF. * This can also be used to detect remote crashes. */ public static ParcelFileDescriptor[] createReliablePipe() throws IOException { try { final FileDescriptor[] comm = createCommSocketPair(); final FileDescriptor[] fds = Os.pipe(); return new ParcelFileDescriptor[] { new ParcelFileDescriptor(fds[0], comm[0]), new ParcelFileDescriptor(fds[1], comm[1]) }; } catch (ErrnoException e) { throw e.rethrowAsIOException(); } } /** * Create two ParcelFileDescriptors structured as a pair of sockets * connected to each other. The two sockets are indistinguishable. */ public static ParcelFileDescriptor[] createSocketPair() throws IOException { return createSocketPair(SOCK_STREAM); } /** * @hide */ public static ParcelFileDescriptor[] createSocketPair(int type) throws IOException { try { final FileDescriptor fd0 = new FileDescriptor(); final FileDescriptor fd1 = new FileDescriptor(); Os.socketpair(AF_UNIX, type, 0, fd0, fd1); return new ParcelFileDescriptor[] { new ParcelFileDescriptor(fd0), new ParcelFileDescriptor(fd1) }; } catch (ErrnoException e) { throw e.rethrowAsIOException(); } } /** * Create two ParcelFileDescriptors structured as a pair of sockets * connected to each other. The two sockets are indistinguishable. * <p> * Both ends have the ability to deliver an error message through * {@link #closeWithError(String)} which can be detected by the other end * calling {@link #checkError()}, usually after detecting an EOF. * This can also be used to detect remote crashes. */ public static ParcelFileDescriptor[] createReliableSocketPair() throws IOException { return createReliableSocketPair(SOCK_STREAM); } /** * @hide */ public static ParcelFileDescriptor[] createReliableSocketPair(int type) throws IOException { try { final FileDescriptor[] comm = createCommSocketPair(); final FileDescriptor fd0 = new FileDescriptor(); final FileDescriptor fd1 = new FileDescriptor(); Os.socketpair(AF_UNIX, type, 0, fd0, fd1); return new ParcelFileDescriptor[] { new ParcelFileDescriptor(fd0, comm[0]), new ParcelFileDescriptor(fd1, comm[1]) }; } catch (ErrnoException e) { throw e.rethrowAsIOException(); } } private static FileDescriptor[] createCommSocketPair() throws IOException { try { // Use SOCK_SEQPACKET so that we have a guarantee that the status // is written and read atomically as one unit and is not split // across multiple IO operations. final FileDescriptor comm1 = new FileDescriptor(); final FileDescriptor comm2 = new FileDescriptor(); Os.socketpair(AF_UNIX, SOCK_SEQPACKET, 0, comm1, comm2); IoUtils.setBlocking(comm1, false); IoUtils.setBlocking(comm2, false); return new FileDescriptor[] { comm1, comm2 }; } catch (ErrnoException e) { throw e.rethrowAsIOException(); } } /** * @hide Please use createPipe() or ContentProvider.openPipeHelper(). * Gets a file descriptor for a read-only copy of the given data. * * @param data Data to copy. * @param name Name for the shared memory area that may back the file descriptor. * This is purely informative and may be {@code null}. * @return A ParcelFileDescriptor. * @throws IOException if there is an error while creating the shared memory area. */ @UnsupportedAppUsage @Deprecated public static ParcelFileDescriptor fromData(byte[] data, String name) throws IOException { if (data == null) return null; MemoryFile file = new MemoryFile(name, data.length); if (data.length > 0) { file.writeBytes(data, 0, 0, data.length); } file.deactivate(); FileDescriptor fd = file.getFileDescriptor(); return fd != null ? ParcelFileDescriptor.dup(fd) : null; } /** * Converts a string representing a file mode, such as "rw", into a bitmask suitable for use * with {@link #open}. * <p> * @param mode The string representation of the file mode. Can be "r", "w", "wt", "wa", "rw" * or "rwt". * @return A bitmask representing the given file mode. * @throws IllegalArgumentException if the given string does not match a known file mode. */ public static int parseMode(String mode) { final int modeBits; if ("r".equals(mode)) { modeBits = ParcelFileDescriptor.MODE_READ_ONLY; } else if ("w".equals(mode) || "wt".equals(mode)) { modeBits = ParcelFileDescriptor.MODE_WRITE_ONLY | ParcelFileDescriptor.MODE_CREATE | ParcelFileDescriptor.MODE_TRUNCATE; } else if ("wa".equals(mode)) { modeBits = ParcelFileDescriptor.MODE_WRITE_ONLY | ParcelFileDescriptor.MODE_CREATE | ParcelFileDescriptor.MODE_APPEND; } else if ("rw".equals(mode)) { modeBits = ParcelFileDescriptor.MODE_READ_WRITE | ParcelFileDescriptor.MODE_CREATE; } else if ("rwt".equals(mode)) { modeBits = ParcelFileDescriptor.MODE_READ_WRITE | ParcelFileDescriptor.MODE_CREATE | ParcelFileDescriptor.MODE_TRUNCATE; } else { throw new IllegalArgumentException("Bad mode '" + mode + "'"); } return modeBits; } /** * Return the filesystem path of the real file on disk that is represented * by the given {@link FileDescriptor}. * * @hide */ @UnsupportedAppUsage public static File getFile(FileDescriptor fd) throws IOException { try { final String path = Os.readlink("/proc/self/fd/" + fd.getInt$()); if (OsConstants.S_ISREG(Os.stat(path).st_mode)) { return new File(path); } else { throw new IOException("Not a regular file: " + path); } } catch (ErrnoException e) { throw e.rethrowAsIOException(); } } /** * Retrieve the actual FileDescriptor associated with this object. * * @return Returns the FileDescriptor associated with this object. */ public FileDescriptor getFileDescriptor() { if (mWrapped != null) { return mWrapped.getFileDescriptor(); } else { return mFd; } } /** * Return the total size of the file representing this fd, as determined by * {@code stat()}. Returns -1 if the fd is not a file. */ public long getStatSize() { if (mWrapped != null) { return mWrapped.getStatSize(); } else { try { final StructStat st = Os.fstat(mFd); if (S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)) { return st.st_size; } else { return -1; } } catch (ErrnoException e) { Log.w(TAG, "fstat() failed: " + e); return -1; } } } /** * This is needed for implementing AssetFileDescriptor.AutoCloseOutputStream, * and I really don't think we want it to be public. * @hide */ @UnsupportedAppUsage public long seekTo(long pos) throws IOException { if (mWrapped != null) { return mWrapped.seekTo(pos); } else { try { return Os.lseek(mFd, pos, SEEK_SET); } catch (ErrnoException e) { throw e.rethrowAsIOException(); } } } /** * Return the native fd int for this ParcelFileDescriptor. The * ParcelFileDescriptor still owns the fd, and it still must be closed * through this API. * <p> * <strong>WARNING:</strong> Do not call close on the return value of this * function or pass it to a function that assumes ownership of the fd. */ public int getFd() { if (mWrapped != null) { return mWrapped.getFd(); } else { if (mClosed) { throw new IllegalStateException("Already closed"); } return mFd.getInt$(); } } /** * Return the native fd int for this ParcelFileDescriptor and detach it from * the object here. You are now responsible for closing the fd in native * code. * <p> * You should not detach when the original creator of the descriptor is * expecting a reliable signal through {@link #close()} or * {@link #closeWithError(String)}. * * @see #canDetectErrors() */ public int detachFd() { if (mWrapped != null) { return mWrapped.detachFd(); } else { if (mClosed) { throw new IllegalStateException("Already closed"); } int fd = IoUtils.acquireRawFd(mFd); writeCommStatusAndClose(Status.DETACHED, null); mClosed = true; mGuard.close(); releaseResources(); return fd; } } /** * Close the ParcelFileDescriptor. This implementation closes the underlying * OS resources allocated to represent this stream. * * @throws IOException * If an error occurs attempting to close this ParcelFileDescriptor. */ @Override public void close() throws IOException { if (mWrapped != null) { try { mWrapped.close(); } finally { releaseResources(); } } else { closeWithStatus(Status.OK, null); } } /** * Close the ParcelFileDescriptor, informing any peer that an error occurred * while processing. If the creator of this descriptor is not observing * errors, it will close normally. * * @param msg describing the error; must not be null. */ public void closeWithError(String msg) throws IOException { if (mWrapped != null) { try { mWrapped.closeWithError(msg); } finally { releaseResources(); } } else { if (msg == null) { throw new IllegalArgumentException("Message must not be null"); } closeWithStatus(Status.ERROR, msg); } } private void closeWithStatus(int status, String msg) { if (mClosed) return; mClosed = true; if (mGuard != null) { mGuard.close(); } // Status MUST be sent before closing actual descriptor writeCommStatusAndClose(status, msg); IoUtils.closeQuietly(mFd); releaseResources(); } /** * Called when the fd is being closed, for subclasses to release any other resources * associated with it, such as acquired providers. * @hide */ public void releaseResources() { } private byte[] getOrCreateStatusBuffer() { if (mStatusBuf == null) { mStatusBuf = new byte[MAX_STATUS]; } return mStatusBuf; } private void writeCommStatusAndClose(int status, String msg) { if (mCommFd == null) { // Not reliable, or someone already sent status if (msg != null) { Log.w(TAG, "Unable to inform peer: " + msg); } return; } if (status == Status.DETACHED) { Log.w(TAG, "Peer expected signal when closed; unable to deliver after detach"); } try { if (status == Status.SILENCE) return; // Since we're about to close, read off any remote status. It's // okay to remember missing here. mStatus = readCommStatus(mCommFd, getOrCreateStatusBuffer()); // Skip writing status when other end has already gone away. if (mStatus != null) return; try { final byte[] buf = getOrCreateStatusBuffer(); int writePtr = 0; Memory.pokeInt(buf, writePtr, status, ByteOrder.BIG_ENDIAN); writePtr += 4; if (msg != null) { final byte[] rawMsg = msg.getBytes(); final int len = Math.min(rawMsg.length, buf.length - writePtr); System.arraycopy(rawMsg, 0, buf, writePtr, len); writePtr += len; } // Must write the entire status as a single operation. Os.write(mCommFd, buf, 0, writePtr); } catch (ErrnoException e) { // Reporting status is best-effort Log.w(TAG, "Failed to report status: " + e); } catch (InterruptedIOException e) { // Reporting status is best-effort Log.w(TAG, "Failed to report status: " + e); } } finally { IoUtils.closeQuietly(mCommFd); mCommFd = null; } } private static Status readCommStatus(FileDescriptor comm, byte[] buf) { try { // Must read the entire status as a single operation. final int n = Os.read(comm, buf, 0, buf.length); if (n == 0) { // EOF means they're dead return new Status(Status.DEAD); } else { final int status = Memory.peekInt(buf, 0, ByteOrder.BIG_ENDIAN); if (status == Status.ERROR) { final String msg = new String(buf, 4, n - 4); return new Status(status, msg); } return new Status(status); } } catch (ErrnoException e) { if (e.errno == OsConstants.EAGAIN) { // Remote is still alive, but no status written yet return null; } else { Log.d(TAG, "Failed to read status; assuming dead: " + e); return new Status(Status.DEAD); } } catch (InterruptedIOException e) { Log.d(TAG, "Failed to read status; assuming dead: " + e); return new Status(Status.DEAD); } } /** * Indicates if this ParcelFileDescriptor can communicate and detect remote * errors/crashes. * * @see #checkError() */ public boolean canDetectErrors() { if (mWrapped != null) { return mWrapped.canDetectErrors(); } else { return mCommFd != null; } } /** * Detect and throw if the other end of a pipe or socket pair encountered an * error or crashed. This allows a reader to distinguish between a valid EOF * and an error/crash. * <p> * If this ParcelFileDescriptor is unable to detect remote errors, it will * return silently. * * @throws IOException for normal errors. * @throws FileDescriptorDetachedException * if the remote side called {@link #detachFd()}. Once detached, the remote * side is unable to communicate any errors through * {@link #closeWithError(String)}. * @see #canDetectErrors() */ public void checkError() throws IOException { if (mWrapped != null) { mWrapped.checkError(); } else { if (mStatus == null) { if (mCommFd == null) { Log.w(TAG, "Peer didn't provide a comm channel; unable to check for errors"); return; } // Try reading status; it might be null if nothing written yet. // Either way, we keep comm open to write our status later. mStatus = readCommStatus(mCommFd, getOrCreateStatusBuffer()); } if (mStatus == null || mStatus.status == Status.OK) { // No status yet, or everything is peachy! return; } else { throw mStatus.asIOException(); } } } /** * An InputStream you can create on a ParcelFileDescriptor, which will * take care of calling {@link ParcelFileDescriptor#close * ParcelFileDescriptor.close()} for you when the stream is closed. */ public static class AutoCloseInputStream extends FileInputStream { private final ParcelFileDescriptor mPfd; public AutoCloseInputStream(ParcelFileDescriptor pfd) { super(pfd.getFileDescriptor()); mPfd = pfd; } @Override public void close() throws IOException { try { super.close(); } finally { mPfd.close(); } } @Override public int read() throws IOException { final int result = super.read(); if (result == -1 && mPfd.canDetectErrors()) { // Check for errors only on EOF, to minimize overhead. mPfd.checkError(); } return result; } @Override public int read(byte[] b) throws IOException { final int result = super.read(b); if (result == -1 && mPfd.canDetectErrors()) { mPfd.checkError(); } return result; } @Override public int read(byte[] b, int off, int len) throws IOException { final int result = super.read(b, off, len); if (result == -1 && mPfd.canDetectErrors()) { mPfd.checkError(); } return result; } } /** * An OutputStream you can create on a ParcelFileDescriptor, which will * take care of calling {@link ParcelFileDescriptor#close * ParcelFileDescriptor.close()} for you when the stream is closed. */ public static class AutoCloseOutputStream extends FileOutputStream { private final ParcelFileDescriptor mPfd; public AutoCloseOutputStream(ParcelFileDescriptor pfd) { super(pfd.getFileDescriptor()); mPfd = pfd; } @Override public void close() throws IOException { try { super.close(); } finally { mPfd.close(); } } } @Override public String toString() { if (mWrapped != null) { return mWrapped.toString(); } else { return "{ParcelFileDescriptor: " + mFd + "}"; } } @Override protected void finalize() throws Throwable { if (mWrapped != null) { releaseResources(); } if (mGuard != null) { mGuard.warnIfOpen(); } try { if (!mClosed) { closeWithStatus(Status.LEAKED, null); } } finally { super.finalize(); } } @Override public int describeContents() { if (mWrapped != null) { return mWrapped.describeContents(); } else { return Parcelable.CONTENTS_FILE_DESCRIPTOR; } } /** * {@inheritDoc} * If {@link Parcelable#PARCELABLE_WRITE_RETURN_VALUE} is set in flags, * the file descriptor will be closed after a copy is written to the Parcel. */ @Override public void writeToParcel(Parcel out, int flags) { if (mWrapped != null) { try { mWrapped.writeToParcel(out, flags); } finally { releaseResources(); } } else { if (mCommFd != null) { out.writeInt(1); out.writeFileDescriptor(mFd); out.writeFileDescriptor(mCommFd); } else { out.writeInt(0); out.writeFileDescriptor(mFd); } if ((flags & PARCELABLE_WRITE_RETURN_VALUE) != 0 && !mClosed) { // Not a real close, so emit no status closeWithStatus(Status.SILENCE, null); } } } public static final Parcelable.Creator<ParcelFileDescriptor> CREATOR = new Parcelable.Creator<ParcelFileDescriptor>() { @Override public ParcelFileDescriptor createFromParcel(Parcel in) { int hasCommChannel = in.readInt(); final FileDescriptor fd = in.readRawFileDescriptor(); FileDescriptor commChannel = null; if (hasCommChannel != 0) { commChannel = in.readRawFileDescriptor(); } return new ParcelFileDescriptor(fd, commChannel); } @Override public ParcelFileDescriptor[] newArray(int size) { return new ParcelFileDescriptor[size]; } }; /** * Callback indicating that a ParcelFileDescriptor has been closed. */ public interface OnCloseListener { /** * Event indicating the ParcelFileDescriptor to which this listener was * attached has been closed. * * @param e error state, or {@code null} if closed cleanly. * If the close event was the result of * {@link ParcelFileDescriptor#detachFd()}, this will be a * {@link FileDescriptorDetachedException}. After detach the * remote side may continue reading/writing to the underlying * {@link FileDescriptor}, but they can no longer deliver * reliable close/error events. */ public void onClose(IOException e); } /** * Exception that indicates that the file descriptor was detached. */ public static class FileDescriptorDetachedException extends IOException { private static final long serialVersionUID = 0xDe7ac4edFdL; public FileDescriptorDetachedException() { super("Remote side is detached"); } } /** * Internal class representing a remote status read by * {@link ParcelFileDescriptor#readCommStatus(FileDescriptor, byte[])}. * * Warning: this must be kept in sync with ParcelFileDescriptorStatus at * frameworks/native/libs/binder/Parcel.cpp */ private static class Status { /** Special value indicating remote side died. */ public static final int DEAD = -2; /** Special value indicating no status should be written. */ public static final int SILENCE = -1; /** Remote reported that everything went better than expected. */ public static final int OK = 0; /** Remote reported error; length and message follow. */ public static final int ERROR = 1; /** Remote reported {@link #detachFd()} and went rogue. */ public static final int DETACHED = 2; /** Remote reported their object was finalized. */ public static final int LEAKED = 3; public final int status; public final String msg; public Status(int status) { this(status, null); } public Status(int status, String msg) { this.status = status; this.msg = msg; } public IOException asIOException() { switch (status) { case DEAD: return new IOException("Remote side is dead"); case OK: return null; case ERROR: return new IOException("Remote error: " + msg); case DETACHED: return new FileDescriptorDetachedException(); case LEAKED: return new IOException("Remote side was leaked"); default: return new IOException("Unknown status: " + status); } } @Override public String toString() { return "{" + status + ": " + msg + "}"; } } }