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      1 /*
      2  * Copyright (C) 2007 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 android.net;
     18 
     19 import java.io.Closeable;
     20 import java.io.FileDescriptor;
     21 import java.io.IOException;
     22 
     23 /**
     24  * Non-standard class for creating an inbound UNIX-domain socket
     25  * in the Linux abstract namespace.
     26  */
     27 public class LocalServerSocket implements Closeable {
     28     private final LocalSocketImpl impl;
     29     private final LocalSocketAddress localAddress;
     30 
     31     /** 50 seems a bit much, but it's what was here */
     32     private static final int LISTEN_BACKLOG = 50;
     33 
     34     /**
     35      * Creates a new server socket listening at specified name.
     36      * On the Android platform, the name is created in the Linux
     37      * abstract namespace (instead of on the filesystem).
     38      *
     39      * @param name address for socket
     40      * @throws IOException
     41      */
     42     public LocalServerSocket(String name) throws IOException
     43     {
     44         impl = new LocalSocketImpl();
     45 
     46         impl.create(LocalSocket.SOCKET_STREAM);
     47 
     48         localAddress = new LocalSocketAddress(name);
     49         impl.bind(localAddress);
     50 
     51         impl.listen(LISTEN_BACKLOG);
     52     }
     53 
     54     /**
     55      * Create a LocalServerSocket from a file descriptor that's already
     56      * been created and bound. listen() will be called immediately on it.
     57      * Used for cases where file descriptors are passed in via environment
     58      * variables
     59      *
     60      * @param fd bound file descriptor
     61      * @throws IOException
     62      */
     63     public LocalServerSocket(FileDescriptor fd) throws IOException
     64     {
     65         impl = new LocalSocketImpl(fd);
     66         impl.listen(LISTEN_BACKLOG);
     67         localAddress = impl.getSockAddress();
     68     }
     69 
     70     /**
     71      * Obtains the socket's local address
     72      *
     73      * @return local address
     74      */
     75     public LocalSocketAddress getLocalSocketAddress()
     76     {
     77         return localAddress;
     78     }
     79 
     80     /**
     81      * Accepts a new connection to the socket. Blocks until a new
     82      * connection arrives.
     83      *
     84      * @return a socket representing the new connection.
     85      * @throws IOException
     86      */
     87     public LocalSocket accept() throws IOException
     88     {
     89         LocalSocketImpl acceptedImpl = new LocalSocketImpl();
     90 
     91         impl.accept(acceptedImpl);
     92 
     93         return LocalSocket.createLocalSocketForAccept(acceptedImpl);
     94     }
     95 
     96     /**
     97      * Returns file descriptor or null if not yet open/already closed
     98      *
     99      * @return fd or null
    100      */
    101     public FileDescriptor getFileDescriptor() {
    102         return impl.getFileDescriptor();
    103     }
    104 
    105     /**
    106      * Closes server socket.
    107      *
    108      * @throws IOException
    109      */
    110     @Override public void close() throws IOException
    111     {
    112         impl.close();
    113     }
    114 }
    115