1 /*
2  * Copyright (C) 2019 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.providers.media;
18 
19 import static com.android.providers.media.DatabaseHelper.EXTERNAL_DATABASE_NAME;
20 import static com.android.providers.media.DatabaseHelper.INTERNAL_DATABASE_NAME;
21 
22 import android.content.ContentProvider;
23 import android.content.ContentProviderOperation;
24 import android.content.ContentProviderResult;
25 import android.content.ContentUris;
26 import android.content.ContentValues;
27 import android.content.Context;
28 import android.content.OperationApplicationException;
29 import android.content.pm.ProviderInfo;
30 import android.database.Cursor;
31 import android.net.Uri;
32 import android.os.Bundle;
33 import android.provider.MediaStore;
34 import android.provider.MediaStore.MediaColumns;
35 import android.util.ArraySet;
36 
37 import androidx.annotation.NonNull;
38 
39 import com.android.providers.media.util.Logging;
40 
41 import java.io.File;
42 import java.io.FileDescriptor;
43 import java.io.IOException;
44 import java.io.PrintWriter;
45 import java.util.ArrayList;
46 import java.util.Objects;
47 import java.util.Set;
48 
49 /**
50  * Very limited subset of {@link MediaProvider} which only surfaces
51  * {@link android.provider.MediaStore.Files} data.
52  */
53 public class LegacyMediaProvider extends ContentProvider {
54     private DatabaseHelper mInternalDatabase;
55     private DatabaseHelper mExternalDatabase;
56 
57     public static final String START_LEGACY_MIGRATION_CALL = "start_legacy_migration";
58     public static final String FINISH_LEGACY_MIGRATION_CALL = "finish_legacy_migration";
59 
60     @Override
attachInfo(Context context, ProviderInfo info)61     public void attachInfo(Context context, ProviderInfo info) {
62         // Sanity check our setup
63         if (!info.exported) {
64             throw new SecurityException("Provider must be exported");
65         }
66         if (!android.Manifest.permission.WRITE_MEDIA_STORAGE.equals(info.readPermission)
67                 || !android.Manifest.permission.WRITE_MEDIA_STORAGE.equals(info.writePermission)) {
68             throw new SecurityException("Provider must be protected by WRITE_MEDIA_STORAGE");
69         }
70 
71         super.attachInfo(context, info);
72     }
73 
74     @Override
onCreate()75     public boolean onCreate() {
76         final Context context = getContext();
77 
78         final File persistentDir = context.getDir("logs", Context.MODE_PRIVATE);
79         Logging.initPersistent(persistentDir);
80 
81         mInternalDatabase = new DatabaseHelper(context, INTERNAL_DATABASE_NAME,
82                 true, false, true, null, null, null, null, null);
83         mExternalDatabase = new DatabaseHelper(context, EXTERNAL_DATABASE_NAME,
84                 false, false, true, null, null, null, null, null);
85 
86         return true;
87     }
88 
getDatabaseForUri(Uri uri)89     private @NonNull DatabaseHelper getDatabaseForUri(Uri uri) {
90         final String volumeName = MediaStore.getVolumeName(uri);
91         switch (volumeName) {
92             case MediaStore.VOLUME_INTERNAL:
93                 return Objects.requireNonNull(mInternalDatabase, "Missing internal database");
94             default:
95                 return Objects.requireNonNull(mExternalDatabase, "Missing external database");
96         }
97     }
98 
99     @Override
query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)100     public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
101             String sortOrder) {
102         final DatabaseHelper helper = getDatabaseForUri(uri);
103         return helper.runWithoutTransaction((db) -> {
104             return db.query("files", projection, selection, selectionArgs,
105                     null, null, sortOrder);
106         });
107     }
108 
109     @Override
getType(Uri uri)110     public String getType(Uri uri) {
111         throw new UnsupportedOperationException();
112     }
113 
114     @Override
applyBatch(ArrayList<ContentProviderOperation> operations)115     public ContentProviderResult[] applyBatch(ArrayList<ContentProviderOperation> operations)
116                 throws OperationApplicationException {
117         // Open transactions on databases for requested volumes
118         final Set<DatabaseHelper> transactions = new ArraySet<>();
119         try {
120             for (ContentProviderOperation op : operations) {
121                 final DatabaseHelper helper = getDatabaseForUri(op.getUri());
122                 if (!transactions.contains(helper)) {
123                     helper.beginTransaction();
124                     transactions.add(helper);
125                 }
126             }
127 
128             final ContentProviderResult[] result = super.applyBatch(operations);
129             for (DatabaseHelper helper : transactions) {
130                 helper.setTransactionSuccessful();
131             }
132             return result;
133         } finally {
134             for (DatabaseHelper helper : transactions) {
135                 helper.endTransaction();
136             }
137         }
138     }
139 
140     @Override
insert(Uri uri, ContentValues values)141     public Uri insert(Uri uri, ContentValues values) {
142         if (!uri.getBooleanQueryParameter("silent", false)) {
143             try {
144                 final File file = new File(values.getAsString(MediaColumns.DATA));
145                 file.getParentFile().mkdirs();
146                 file.createNewFile();
147             } catch (IOException e) {
148                 throw new IllegalStateException(e);
149             }
150         }
151 
152         final DatabaseHelper helper = getDatabaseForUri(uri);
153         final long id = helper.runWithTransaction((db) -> {
154             return db.insert("files", null, values);
155         });
156         return ContentUris.withAppendedId(uri, id);
157     }
158 
159     @Override
delete(Uri uri, String selection, String[] selectionArgs)160     public int delete(Uri uri, String selection, String[] selectionArgs) {
161         throw new UnsupportedOperationException();
162     }
163 
164     @Override
update(Uri uri, ContentValues values, String selection, String[] selectionArgs)165     public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
166         throw new UnsupportedOperationException();
167     }
168 
169     @Override
call(String authority, String method, String arg, Bundle extras)170     public Bundle call(String authority, String method, String arg, Bundle extras) {
171         switch (method) {
172             case START_LEGACY_MIGRATION_CALL: {
173                 // Nice to know, but nothing actionable
174                 break;
175             }
176             case FINISH_LEGACY_MIGRATION_CALL: {
177                 // We're only going to hear this once, since we've either
178                 // successfully migrated legacy data, or we're never going to
179                 // try again, so it's time to clean things up
180                 final String volumeName = arg;
181                 switch (volumeName) {
182                     case MediaStore.VOLUME_INTERNAL: {
183                         mInternalDatabase.close();
184                         getContext().deleteDatabase(INTERNAL_DATABASE_NAME);
185                         break;
186                     }
187                     default: {
188                         mExternalDatabase.close();
189                         getContext().deleteDatabase(EXTERNAL_DATABASE_NAME);
190                         break;
191                     }
192                 }
193             }
194         }
195         return null;
196     }
197 
198     @Override
dump(FileDescriptor fd, PrintWriter writer, String[] args)199     public void dump(FileDescriptor fd, PrintWriter writer, String[] args) {
200         Logging.dumpPersistent(writer);
201     }
202 }
203