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      1 /*
      2  * Copyright (C) 2009 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 package android.os.cts;
     17 
     18 import android.os.Environment;
     19 import android.system.Os;
     20 import android.system.StructStatVfs;
     21 
     22 import junit.framework.TestCase;
     23 
     24 import java.io.BufferedReader;
     25 import java.io.File;
     26 import java.io.FileReader;
     27 
     28 public class EnvironmentTest extends TestCase {
     29     public void testEnvironment() {
     30         new Environment();
     31         assertNotNull(Environment.getExternalStorageState());
     32         assertTrue(Environment.getExternalStorageDirectory().isDirectory());
     33         assertTrue(Environment.getRootDirectory().isDirectory());
     34         assertTrue(Environment.getDownloadCacheDirectory().isDirectory());
     35         assertTrue(Environment.getDataDirectory().isDirectory());
     36     }
     37 
     38     /**
     39      * TMPDIR being set prevents apps from asking to have temporary files
     40      * placed in their own storage, instead forcing their location to
     41      * something OS-defined. If TMPDIR points to a global shared directory,
     42      * this could compromise the security of the files.
     43      */
     44     public void testNoTmpDir() {
     45         assertNull("environment variable TMPDIR should not be set",
     46                 System.getenv("TMPDIR"));
     47     }
     48 
     49     /**
     50      * Verify that all writable block filesystems are mounted "noatime" to avoid
     51      * unnecessary flash churn.
     52      */
     53     public void testNoAtime() throws Exception {
     54         try (BufferedReader br = new BufferedReader(new FileReader("/proc/mounts"))) {
     55             String line;
     56             while ((line = br.readLine()) != null) {
     57                 final String[] fields = line.split(" ");
     58                 final String source = fields[0];
     59                 final String options = fields[3];
     60 
     61                 if (source.startsWith("/dev/block/") && !options.startsWith("ro,")
     62                         && !options.contains("noatime")) {
     63                     fail("Found device mounted at " + source + " without 'noatime' option, "
     64                             + "which can cause unnecessary flash churn; please update your fstab.");
     65                 }
     66             }
     67         }
     68     }
     69 
     70     /**
     71      * Verify that all writable block filesystems are mounted with "resgid" to
     72      * mitigate disk-full trouble.
     73      */
     74     public void testSaneInodes() throws Exception {
     75         final File file = Environment.getDataDirectory();
     76         final StructStatVfs stat = Os.statvfs(file.getAbsolutePath());
     77 
     78         // By default ext4 creates one inode per 16KiB; we're okay with a much
     79         // wider range, but we want to make sure the device isn't going totally
     80         // crazy; too few inodes can result in system instability, and too many
     81         // inodes can result in wasted space.
     82         final long maxsize = stat.f_blocks * stat.f_frsize;
     83         final long maxInodes = maxsize / 4096;
     84         final long minsize = stat.f_bavail * stat.f_frsize;
     85         final long minInodes = minsize / 32768;
     86 
     87         if (stat.f_ffree >= minInodes && stat.f_ffree <= maxInodes) {
     88             // Sweet, sounds great!
     89         } else {
     90             fail("Number of inodes " + stat.f_ffree + " not within sane range for partition of "
     91                     + minsize + "," + maxsize + " bytes; expected [" + minInodes + "," + maxInodes + "]");
     92         }
     93     }
     94 }
     95