1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 * Copyright (c) 1995, 2016, Oracle and/or its affiliates. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.  Oracle designates this
9 * particular file as subject to the "Classpath" exception as provided
10 * by Oracle in the LICENSE file that accompanied this code.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
23 * or visit www.oracle.com if you need additional information or have any
24 * questions.
25 */
26
27package java.net;
28
29import java.io.FileDescriptor;
30import java.io.FileInputStream;
31import java.io.IOException;
32import java.nio.channels.FileChannel;
33
34import dalvik.system.BlockGuard;
35import sun.net.ConnectionResetException;
36
37/**
38 * This stream extends FileInputStream to implement a
39 * SocketInputStream. Note that this class should <b>NOT</b> be
40 * public.
41 *
42 * @author      Jonathan Payne
43 * @author      Arthur van Hoff
44 */
45class SocketInputStream extends FileInputStream
46{
47    // Android-removed: Android doesn't need to call native init.
48    // static {
49    //    init();
50    //}
51
52    private boolean eof;
53    private AbstractPlainSocketImpl impl = null;
54    private byte temp[];
55    private Socket socket = null;
56
57    /**
58     * Creates a new SocketInputStream. Can only be called
59     * by a Socket. This method needs to hang on to the owner Socket so
60     * that the fd will not be closed.
61     * @param impl the implemented socket input stream
62     */
63    SocketInputStream(AbstractPlainSocketImpl impl) throws IOException {
64        super(impl.getFileDescriptor());
65        this.impl = impl;
66        socket = impl.getSocket();
67    }
68
69    /**
70     * Returns the unique {@link java.nio.channels.FileChannel FileChannel}
71     * object associated with this file input stream.</p>
72     *
73     * The {@code getChannel} method of {@code SocketInputStream}
74     * returns {@code null} since it is a socket based stream.</p>
75     *
76     * @return  the file channel associated with this file input stream
77     *
78     * @since 1.4
79     * @spec JSR-51
80     */
81    public final FileChannel getChannel() {
82        return null;
83    }
84
85    /**
86     * Reads into an array of bytes at the specified offset using
87     * the received socket primitive.
88     * @param fd the FileDescriptor
89     * @param b the buffer into which the data is read
90     * @param off the start offset of the data
91     * @param len the maximum number of bytes read
92     * @param timeout the read timeout in ms
93     * @return the actual number of bytes read, -1 is
94     *          returned when the end of the stream is reached.
95     * @exception IOException If an I/O error has occurred.
96     */
97    private native int socketRead0(FileDescriptor fd,
98                                   byte b[], int off, int len,
99                                   int timeout)
100        throws IOException;
101
102    // wrap native call to allow instrumentation
103    /**
104     * Reads into an array of bytes at the specified offset using
105     * the received socket primitive.
106     * @param fd the FileDescriptor
107     * @param b the buffer into which the data is read
108     * @param off the start offset of the data
109     * @param len the maximum number of bytes read
110     * @param timeout the read timeout in ms
111     * @return the actual number of bytes read, -1 is
112     *          returned when the end of the stream is reached.
113     * @exception IOException If an I/O error has occurred.
114     */
115    private int socketRead(FileDescriptor fd,
116                           byte b[], int off, int len,
117                           int timeout)
118        throws IOException {
119        return socketRead0(fd, b, off, len, timeout);
120    }
121
122    /**
123     * Reads into a byte array data from the socket.
124     * @param b the buffer into which the data is read
125     * @return the actual number of bytes read, -1 is
126     *          returned when the end of the stream is reached.
127     * @exception IOException If an I/O error has occurred.
128     */
129    public int read(byte b[]) throws IOException {
130        return read(b, 0, b.length);
131    }
132
133    /**
134     * Reads into a byte array <i>b</i> at offset <i>off</i>,
135     * <i>length</i> bytes of data.
136     * @param b the buffer into which the data is read
137     * @param off the start offset of the data
138     * @param length the maximum number of bytes read
139     * @return the actual number of bytes read, -1 is
140     *          returned when the end of the stream is reached.
141     * @exception IOException If an I/O error has occurred.
142     */
143    public int read(byte b[], int off, int length) throws IOException {
144        return read(b, off, length, impl.getTimeout());
145    }
146
147    int read(byte b[], int off, int length, int timeout) throws IOException {
148        int n;
149
150        // EOF already encountered
151        if (eof) {
152            return -1;
153        }
154
155        // connection reset
156        if (impl.isConnectionReset()) {
157            throw new SocketException("Connection reset");
158        }
159
160        // bounds check
161        if (length <= 0 || off < 0 || length > b.length - off) {
162            if (length == 0) {
163                return 0;
164            }
165            throw new ArrayIndexOutOfBoundsException("length == " + length
166                    + " off == " + off + " buffer length == " + b.length);
167        }
168
169        boolean gotReset = false;
170
171        // acquire file descriptor and do the read
172        FileDescriptor fd = impl.acquireFD();
173        try {
174            // Android-added: Check BlockGuard policy in read().
175            BlockGuard.getThreadPolicy().onNetwork();
176            n = socketRead(fd, b, off, length, timeout);
177            if (n > 0) {
178                return n;
179            }
180        } catch (ConnectionResetException rstExc) {
181            gotReset = true;
182        } finally {
183            impl.releaseFD();
184        }
185
186        /*
187         * We receive a "connection reset" but there may be bytes still
188         * buffered on the socket
189         */
190        if (gotReset) {
191            impl.setConnectionResetPending();
192            impl.acquireFD();
193            try {
194                n = socketRead(fd, b, off, length, timeout);
195                if (n > 0) {
196                    return n;
197                }
198            } catch (ConnectionResetException rstExc) {
199            } finally {
200                impl.releaseFD();
201            }
202        }
203
204        /*
205         * If we get here we are at EOF, the socket has been closed,
206         * or the connection has been reset.
207         */
208        if (impl.isClosedOrPending()) {
209            throw new SocketException("Socket closed");
210        }
211        if (impl.isConnectionResetPending()) {
212            impl.setConnectionReset();
213        }
214        if (impl.isConnectionReset()) {
215            throw new SocketException("Connection reset");
216        }
217        eof = true;
218        return -1;
219    }
220
221    /**
222     * Reads a single byte from the socket.
223     */
224    public int read() throws IOException {
225        if (eof) {
226            return -1;
227        }
228        temp = new byte[1];
229        int n = read(temp, 0, 1);
230        if (n <= 0) {
231            return -1;
232        }
233        return temp[0] & 0xff;
234    }
235
236    /**
237     * Skips n bytes of input.
238     * @param numbytes the number of bytes to skip
239     * @return  the actual number of bytes skipped.
240     * @exception IOException If an I/O error has occurred.
241     */
242    public long skip(long numbytes) throws IOException {
243        if (numbytes <= 0) {
244            return 0;
245        }
246        long n = numbytes;
247        int buflen = (int) Math.min(1024, n);
248        byte data[] = new byte[buflen];
249        while (n > 0) {
250            int r = read(data, 0, (int) Math.min((long) buflen, n));
251            if (r < 0) {
252                break;
253            }
254            n -= r;
255        }
256        return numbytes - n;
257    }
258
259    /**
260     * Returns the number of bytes that can be read without blocking.
261     * @return the number of immediately available bytes
262     */
263    public int available() throws IOException {
264        // Android-changed: Bug fix, if eof == true, we must indicate that we
265        // have 0 bytes available.
266        if (eof) {
267            return 0;
268        } else {
269            return impl.available();
270        }
271    }
272
273    /**
274     * Closes the stream.
275     */
276    private boolean closing = false;
277    public void close() throws IOException {
278        // Prevent recursion. See BugId 4484411
279        if (closing)
280            return;
281        closing = true;
282        if (socket != null) {
283            if (!socket.isClosed())
284                socket.close();
285        } else
286            impl.close();
287        closing = false;
288    }
289
290    void setEOF(boolean eof) {
291        this.eof = eof;
292    }
293
294    /**
295     * Overrides finalize, the fd is closed by the Socket.
296     */
297    protected void finalize() {}
298
299    // Android-removed: Android doesn't need native init.
300    /*
301     * Perform class load-time initializations.
302     *
303    private native static void init();
304    */
305}
306