1 /*
2  * Copyright (C) 2024 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.settings.development;
18 
19 import android.content.Context;
20 import android.content.Intent;
21 import android.os.SystemProperties;
22 import android.os.UserHandle;
23 import android.os.UserManager;
24 import android.service.oemlock.OemLockManager;
25 import android.system.Os;
26 import android.system.OsConstants;
27 import android.util.Log;
28 
29 import androidx.annotation.NonNull;
30 import androidx.annotation.VisibleForTesting;
31 
32 import java.io.BufferedReader;
33 import java.io.FileReader;
34 import java.io.IOException;
35 
36 public class Enable16kUtils {
37     private static final long PAGE_SIZE = Os.sysconf(OsConstants._SC_PAGESIZE);
38     private static final int PAGE_SIZE_16KB = 16 * 1024;
39 
40     @VisibleForTesting
41     static final String DEV_OPTION_PROPERTY = "ro.product.build.16k_page.enabled";
42 
43     private static final String TAG = "Enable16kUtils";
44 
45     /**
46      * @param context uses context to retrieve OEM unlock info
47      * @return true if device is OEM unlocked and factory reset is allowed for user.
48      */
isDeviceOEMUnlocked(@onNull Context context)49     public static boolean isDeviceOEMUnlocked(@NonNull Context context) {
50         // OEM unlock is checked for bootloader, carrier and user. Check all three to ensure
51         // that device is unlocked and it is also allowed by user as well as carrier
52         final OemLockManager oemLockManager = context.getSystemService(OemLockManager.class);
53         final UserManager userManager = context.getSystemService(UserManager.class);
54         if (oemLockManager == null || userManager == null) {
55             Log.e(TAG, "Required services not found on device to check for OEM unlock state.");
56             return false;
57         }
58 
59         // If either of device or carrier is not allowed to unlock, return false
60         if (!oemLockManager.isDeviceOemUnlocked()) {
61             Log.e(TAG, "Device is not OEM unlocked");
62             return false;
63         }
64 
65         final UserHandle userHandle = UserHandle.of(UserHandle.myUserId());
66         if (userManager.hasBaseUserRestriction(UserManager.DISALLOW_FACTORY_RESET, userHandle)) {
67             Log.e(TAG, "Factory reset is not allowed for user.");
68             return false;
69         }
70 
71         return true;
72     }
73 
74     /**
75      * @return true if /data partition is ext4
76      */
isDataExt4()77     public static boolean isDataExt4() {
78         try (BufferedReader br = new BufferedReader(new FileReader("/proc/mounts"))) {
79             String line;
80             while ((line = br.readLine()) != null) {
81                 Log.i(TAG, line);
82                 final String[] fields = line.split(" ");
83                 final String partition = fields[1];
84                 final String fsType = fields[2];
85                 if (partition.equals("/data") && fsType.equals("ext4")) {
86                     return true;
87                 }
88             }
89         } catch (IOException e) {
90             Log.e(TAG, "Failed to read /proc/mounts");
91         }
92 
93         return false;
94     }
95 
96     /**
97      * @return returns true if 16KB developer option is available for the device.
98      */
is16KbToggleAvailable()99     public static boolean is16KbToggleAvailable() {
100         return SystemProperties.getBoolean(DEV_OPTION_PROPERTY, false);
101     }
102 
103     /**
104      * 16kB page-agnostic mode requires /data to be ext4, ro.product.build.16k_page.enabled for
105      * device and Device OEM unlocked.
106      *
107      * @param context is needed to query OEM unlock state
108      * @return true if device is in page-agnostic mode.
109      */
isPageAgnosticModeOn(@onNull Context context)110     public static boolean isPageAgnosticModeOn(@NonNull Context context) {
111         return is16KbToggleAvailable() && isDeviceOEMUnlocked(context) && isDataExt4();
112     }
113 
114     /**
115      * @return returns true if current page size is 16KB
116      */
isUsing16kbPages()117     public static boolean isUsing16kbPages() {
118         return PAGE_SIZE == PAGE_SIZE_16KB;
119     }
120 
121     /**
122      * show page-agnostic mode warning dialog to user
123      * @param context to start activity
124      */
showPageAgnosticWarning(@onNull Context context)125     public static void showPageAgnosticWarning(@NonNull Context context) {
126         Intent intent = new Intent(context, PageAgnosticWarningActivity.class);
127         context.startActivityAsUser(intent, UserHandle.SYSTEM);
128     }
129 }
130