1 /*
2  * Copyright (C) 2015 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.system;
18 
19 import java.net.SocketAddress;
20 import java.nio.charset.StandardCharsets;
21 import java.util.Arrays;
22 
23 /**
24  * A UNIX-domain (AF_UNIX / AF_LOCAL) socket address.
25  *
26  * @hide
27  */
28 @libcore.api.CorePlatformApi
29 public final class UnixSocketAddress extends SocketAddress {
30 
31     private static final int NAMED_PATH_LENGTH = OsConstants.UNIX_PATH_MAX;
32     private static final byte[] UNNAMED_PATH = new byte[0];
33 
34     // See unix(7): Three types of UnixSocketAddress:
35     // 1) pathname: 0 < sun_path.length <= NAMED_PATH_LENGTH, sun_path[0] != 0.
36     // 2) unnamed: sun_path = [].
37     // 3) abstract: 0 < sun_path.length <= NAMED_PATH_LENGTH, sun_path[0] == 0.
38     private byte[] sun_path;
39 
40     /** This constructor is also used from JNI. */
UnixSocketAddress(byte[] sun_path)41     private UnixSocketAddress(byte[] sun_path) {
42         if (sun_path == null) {
43             throw new IllegalArgumentException("sun_path must not be null");
44         }
45         if (sun_path.length > NAMED_PATH_LENGTH) {
46             throw new IllegalArgumentException("sun_path exceeds the maximum length");
47         }
48 
49         if (sun_path.length == 0) {
50             this.sun_path = UNNAMED_PATH;
51         } else {
52             this.sun_path = new byte[sun_path.length];
53             System.arraycopy(sun_path, 0, this.sun_path, 0, sun_path.length);
54         }
55     }
56 
57     /**
58      * Creates a named, abstract AF_UNIX socket address.
59      */
createAbstract(String name)60     public static UnixSocketAddress createAbstract(String name) {
61         byte[] nameBytes = name.getBytes(StandardCharsets.UTF_8);
62         // Abstract sockets have a path that starts with (byte) 0.
63         byte[] path = new byte[nameBytes.length + 1];
64         System.arraycopy(nameBytes, 0, path, 1, nameBytes.length);
65         return new UnixSocketAddress(path);
66     }
67 
68     /**
69      * Creates a named, filesystem AF_UNIX socket address.
70      */
71     @libcore.api.CorePlatformApi
createFileSystem(String pathName)72     public static UnixSocketAddress createFileSystem(String pathName) {
73         byte[] pathNameBytes = pathName.getBytes(StandardCharsets.UTF_8);
74         // File system sockets have a path that ends with (byte) 0.
75         byte[] path = new byte[pathNameBytes.length + 1];
76         System.arraycopy(pathNameBytes, 0, path, 0, pathNameBytes.length);
77         return new UnixSocketAddress(path);
78     }
79 
80     /**
81      * Creates an unnamed, filesystem AF_UNIX socket address.
82      */
createUnnamed()83     public static UnixSocketAddress createUnnamed() {
84         return new UnixSocketAddress(UNNAMED_PATH);
85     }
86 
87     /** Used for testing. */
getSunPath()88     public byte[] getSunPath() {
89         if (sun_path.length == 0) {
90             return sun_path;
91         }
92         byte[] sunPathCopy = new byte[sun_path.length];
93         System.arraycopy(sun_path, 0, sunPathCopy, 0, sun_path.length);
94         return sunPathCopy;
95     }
96 
97     @Override
equals(Object o)98     public boolean equals(Object o) {
99         if (this == o) {
100             return true;
101         }
102         if (o == null || getClass() != o.getClass()) {
103             return false;
104         }
105 
106         UnixSocketAddress that = (UnixSocketAddress) o;
107         return Arrays.equals(sun_path, that.sun_path);
108     }
109 
110     @Override
hashCode()111     public int hashCode() {
112         return Arrays.hashCode(sun_path);
113     }
114 
115     @Override
toString()116     public String toString() {
117         return "UnixSocketAddress[" +
118                 "sun_path=" + Arrays.toString(sun_path) +
119                 ']';
120     }
121 }
122