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