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1 /*
2  * Copyright (C) 2021 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.server.uwb;
18 
19 import android.annotation.NonNull;
20 import android.content.Context;
21 import android.content.ContextWrapper;
22 import android.content.Intent;
23 import android.content.pm.PackageManager;
24 import android.content.pm.ResolveInfo;
25 import android.content.res.AssetManager;
26 import android.content.res.Resources;
27 import android.util.Log;
28 
29 import java.util.List;
30 import java.util.stream.Collectors;
31 
32 /**
33  * Wrapper for context to override getResources method. Resources for uwb mainline jar needs to be
34  * fetched from the resources APK.
35  */
36 public class UwbContext extends ContextWrapper {
37     private static final String TAG = "UwbContext";
38     /** Intent action that is used to identify ServiceUwbResources.apk */
39     private static final String ACTION_RESOURCES_APK =
40             "com.android.server.uwb.intent.action.SERVICE_UWB_RESOURCES_APK";
41 
42     /** Since service-uwb runs within system_server, its package name is "android". */
43     private static final String SERVICE_UWB_PACKAGE_NAME = "android";
44 
45     private String mUwbOverlayApkPkgName;
46 
47     // Cached resources from the resources APK.
48     private AssetManager mUwbAssetsFromApk;
49     private Resources mUwbResourcesFromApk;
50     private Resources.Theme mUwbThemeFromApk;
51 
UwbContext(@onNull Context contextBase)52     public UwbContext(@NonNull Context contextBase) {
53         super(contextBase);
54     }
55 
56     /** Get the package name of ServiceUwbResources.apk */
getUwbOverlayApkPkgName()57     public String getUwbOverlayApkPkgName() {
58         if (mUwbOverlayApkPkgName != null) {
59             return mUwbOverlayApkPkgName;
60         }
61 
62         List<ResolveInfo> resolveInfos = getPackageManager().queryIntentActivities(
63                 new Intent(ACTION_RESOURCES_APK),
64                 PackageManager.MATCH_SYSTEM_ONLY);
65 
66         // remove apps that don't live in the Uwb apex
67         resolveInfos.removeIf(info ->
68                 !UwbInjector.isAppInUwbApex(info.activityInfo.applicationInfo));
69 
70         if (resolveInfos.isEmpty()) {
71             // Resource APK not loaded yet, print a stack trace to see where this is called from
72             Log.e(TAG, "Attempted to fetch resources before Uwb Resources APK is loaded!",
73                     new IllegalStateException());
74             return null;
75         }
76 
77         if (resolveInfos.size() > 1) {
78             // multiple apps found, log a warning, but continue
79             Log.w(TAG, "Found > 1 APK that can resolve Uwb Resources APK intent: "
80                     + resolveInfos.stream()
81                             .map(info -> info.activityInfo.applicationInfo.packageName)
82                             .collect(Collectors.joining(", ")));
83         }
84 
85         // Assume the first ResolveInfo is the one we're looking for
86         ResolveInfo info = resolveInfos.get(0);
87         mUwbOverlayApkPkgName = info.activityInfo.applicationInfo.packageName;
88         Log.i(TAG, "Found Uwb Resources APK at: " + mUwbOverlayApkPkgName);
89         return mUwbOverlayApkPkgName;
90     }
91 
getResourcesApkContext()92     private Context getResourcesApkContext() {
93         try {
94             return createPackageContext(getUwbOverlayApkPkgName(), 0);
95         } catch (PackageManager.NameNotFoundException e) {
96             Log.wtf(TAG, "Failed to load resources", e);
97         }
98         return null;
99     }
100 
101     /**
102      * Retrieve assets held in the uwb resources APK.
103      */
104     @Override
getAssets()105     public AssetManager getAssets() {
106         if (mUwbAssetsFromApk == null) {
107             Context resourcesApkContext = getResourcesApkContext();
108             if (resourcesApkContext != null) {
109                 mUwbAssetsFromApk = resourcesApkContext.getAssets();
110             }
111         }
112         return mUwbAssetsFromApk;
113     }
114 
115     /**
116      * Retrieve resources held in the uwb resources APK.
117      */
118     @Override
getResources()119     public Resources getResources() {
120         if (mUwbResourcesFromApk == null) {
121             Context resourcesApkContext = getResourcesApkContext();
122             if (resourcesApkContext != null) {
123                 mUwbResourcesFromApk = resourcesApkContext.getResources();
124             }
125         }
126         return mUwbResourcesFromApk;
127     }
128 
129     /**
130      * Retrieve theme held in the uwb resources APK.
131      */
132     @Override
getTheme()133     public Resources.Theme getTheme() {
134         if (mUwbThemeFromApk == null) {
135             Context resourcesApkContext = getResourcesApkContext();
136             if (resourcesApkContext != null) {
137                 mUwbThemeFromApk = resourcesApkContext.getTheme();
138             }
139         }
140         return mUwbThemeFromApk;
141     }
142 
143     /** Get the package name that service-uwb runs under. */
getServiceUwbPackageName()144     public String getServiceUwbPackageName() {
145         return SERVICE_UWB_PACKAGE_NAME;
146     }
147 }
148