1 /*
2  * Copyright (C) 2016 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 com.android.internal.os;
18 
19 import android.os.Trace;
20 
21 import dalvik.system.DelegateLastClassLoader;
22 import dalvik.system.DexClassLoader;
23 import dalvik.system.PathClassLoader;
24 
25 /**
26  * Creates class loaders.
27  *
28  * @hide
29  */
30 public class ClassLoaderFactory {
31     // Unconstructable
ClassLoaderFactory()32     private ClassLoaderFactory() {}
33 
34     private static final String PATH_CLASS_LOADER_NAME = PathClassLoader.class.getName();
35     private static final String DEX_CLASS_LOADER_NAME = DexClassLoader.class.getName();
36     private static final String DELEGATE_LAST_CLASS_LOADER_NAME =
37             DelegateLastClassLoader.class.getName();
38 
39     /**
40      * Returns true if {@code name} is a supported classloader. {@code name} must be a
41      * binary name of a class, as defined by {@code Class.getName}.
42      */
isValidClassLoaderName(String name)43     public static boolean isValidClassLoaderName(String name) {
44         // This method is used to parse package data and does not accept null names.
45         return name != null && (isPathClassLoaderName(name) || isDelegateLastClassLoaderName(name));
46     }
47 
48     /**
49      * Returns true if {@code name} is the encoding for either PathClassLoader or DexClassLoader.
50      * The two class loaders are grouped together because they have the same behaviour.
51      */
isPathClassLoaderName(String name)52     public static boolean isPathClassLoaderName(String name) {
53         // For null values we default to PathClassLoader. This cover the case when packages
54         // don't specify any value for their class loaders.
55         return name == null || PATH_CLASS_LOADER_NAME.equals(name) ||
56                 DEX_CLASS_LOADER_NAME.equals(name);
57     }
58 
59     /**
60      * Returns true if {@code name} is the encoding for the DelegateLastClassLoader.
61      */
isDelegateLastClassLoaderName(String name)62     public static boolean isDelegateLastClassLoaderName(String name) {
63         return DELEGATE_LAST_CLASS_LOADER_NAME.equals(name);
64     }
65 
66     /**
67      * Same as {@code createClassLoader} below, except that no associated namespace
68      * is created.
69      */
createClassLoader(String dexPath, String librarySearchPath, ClassLoader parent, String classloaderName)70     public static ClassLoader createClassLoader(String dexPath,
71             String librarySearchPath, ClassLoader parent, String classloaderName) {
72         if (isPathClassLoaderName(classloaderName)) {
73             return new PathClassLoader(dexPath, librarySearchPath, parent);
74         } else if (isDelegateLastClassLoaderName(classloaderName)) {
75             return new DelegateLastClassLoader(dexPath, librarySearchPath, parent);
76         }
77 
78         throw new AssertionError("Invalid classLoaderName: " + classloaderName);
79     }
80 
81     /**
82      * Create a ClassLoader and initialize a linker-namespace for it.
83      */
createClassLoader(String dexPath, String librarySearchPath, String libraryPermittedPath, ClassLoader parent, int targetSdkVersion, boolean isNamespaceShared, String classloaderName)84     public static ClassLoader createClassLoader(String dexPath,
85             String librarySearchPath, String libraryPermittedPath, ClassLoader parent,
86             int targetSdkVersion, boolean isNamespaceShared, String classloaderName) {
87 
88         final ClassLoader classLoader = createClassLoader(dexPath, librarySearchPath, parent,
89                 classloaderName);
90 
91         boolean isForVendor = false;
92         for (String path : dexPath.split(":")) {
93             if (path.startsWith("/vendor/")) {
94                 isForVendor = true;
95                 break;
96             }
97         }
98         Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "createClassloaderNamespace");
99         String errorMessage = createClassloaderNamespace(classLoader,
100                                                          targetSdkVersion,
101                                                          librarySearchPath,
102                                                          libraryPermittedPath,
103                                                          isNamespaceShared,
104                                                          isForVendor);
105         Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
106 
107         if (errorMessage != null) {
108             throw new UnsatisfiedLinkError("Unable to create namespace for the classloader " +
109                                            classLoader + ": " + errorMessage);
110         }
111 
112         return classLoader;
113     }
114 
createClassloaderNamespace(ClassLoader classLoader, int targetSdkVersion, String librarySearchPath, String libraryPermittedPath, boolean isNamespaceShared, boolean isForVendor)115     private static native String createClassloaderNamespace(ClassLoader classLoader,
116                                                             int targetSdkVersion,
117                                                             String librarySearchPath,
118                                                             String libraryPermittedPath,
119                                                             boolean isNamespaceShared,
120                                                             boolean isForVendor);
121 }
122