1/*
2 * Copyright (C) 2015 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 */
16package libcore.tzdata.update;
17
18import android.util.Slog;
19
20import java.io.File;
21import java.io.IOException;
22
23/**
24 * A bundle-validation / extraction class. Separate from the services code that uses it for easier
25 * testing.
26 */
27public final class TzDataBundleInstaller {
28
29    static final String CURRENT_TZ_DATA_DIR_NAME = "current";
30    static final String WORKING_DIR_NAME = "working";
31    static final String OLD_TZ_DATA_DIR_NAME = "old";
32
33    private final String logTag;
34    private final File installDir;
35
36    public TzDataBundleInstaller(String logTag, File installDir) {
37        this.logTag = logTag;
38        this.installDir = installDir;
39    }
40
41    /**
42     * Install the supplied content.
43     *
44     * <p>Errors during unpacking or installation will throw an {@link IOException}.
45     * If the content is invalid this method returns {@code false}.
46     * If the installation completed successfully this method returns {@code true}.
47     */
48    public boolean install(byte[] content) throws IOException {
49        File oldTzDataDir = new File(installDir, OLD_TZ_DATA_DIR_NAME);
50        if (oldTzDataDir.exists()) {
51            FileUtils.deleteRecursive(oldTzDataDir);
52        }
53
54        File currentTzDataDir = new File(installDir, CURRENT_TZ_DATA_DIR_NAME);
55        File workingDir = new File(installDir, WORKING_DIR_NAME);
56
57        Slog.i(logTag, "Applying time zone update");
58        File unpackedContentDir = unpackBundle(content, workingDir);
59        try {
60            if (!checkBundleFilesExist(unpackedContentDir)) {
61                Slog.i(logTag, "Update not applied: Bundle is missing files");
62                return false;
63            }
64
65            if (verifySystemChecksums(unpackedContentDir)) {
66                FileUtils.makeDirectoryWorldAccessible(unpackedContentDir);
67
68                if (currentTzDataDir.exists()) {
69                    Slog.i(logTag, "Moving " + currentTzDataDir + " to " + oldTzDataDir);
70                    FileUtils.rename(currentTzDataDir, oldTzDataDir);
71                }
72                Slog.i(logTag, "Moving " + unpackedContentDir + " to " + currentTzDataDir);
73                FileUtils.rename(unpackedContentDir, currentTzDataDir);
74                Slog.i(logTag, "Update applied: " + currentTzDataDir + " successfully created");
75                return true;
76            }
77            Slog.i(logTag, "Update not applied: System checksum did not match");
78            return false;
79        } finally {
80            deleteBestEffort(oldTzDataDir);
81            deleteBestEffort(unpackedContentDir);
82        }
83    }
84
85    private void deleteBestEffort(File dir) {
86        if (dir.exists()) {
87            try {
88                FileUtils.deleteRecursive(dir);
89            } catch (IOException e) {
90                // Logged but otherwise ignored.
91                Slog.w(logTag, "Unable to delete " + dir, e);
92            }
93        }
94    }
95
96    private File unpackBundle(byte[] content, File targetDir) throws IOException {
97        Slog.i(logTag, "Unpacking update content to: " + targetDir);
98        ConfigBundle bundle = new ConfigBundle(content);
99        bundle.extractTo(targetDir);
100        return targetDir;
101    }
102
103    private boolean checkBundleFilesExist(File unpackedContentDir) throws IOException {
104        Slog.i(logTag, "Verifying bundle contents");
105        return FileUtils.filesExist(unpackedContentDir,
106                ConfigBundle.TZ_DATA_VERSION_FILE_NAME,
107                ConfigBundle.CHECKSUMS_FILE_NAME,
108                ConfigBundle.ZONEINFO_FILE_NAME,
109                ConfigBundle.ICU_DATA_FILE_NAME);
110    }
111
112    private boolean verifySystemChecksums(File unpackedContentDir) throws IOException {
113        Slog.i(logTag, "Verifying system file checksums");
114        File checksumsFile = new File(unpackedContentDir, ConfigBundle.CHECKSUMS_FILE_NAME);
115        for (String line : FileUtils.readLines(checksumsFile)) {
116            int delimiterPos = line.indexOf(',');
117            if (delimiterPos <= 0 || delimiterPos == line.length() - 1) {
118                throw new IOException("Bad checksum entry: " + line);
119            }
120            long expectedChecksum;
121            try {
122                expectedChecksum = Long.parseLong(line.substring(0, delimiterPos));
123            } catch (NumberFormatException e) {
124                throw new IOException("Invalid checksum value: " + line);
125            }
126            String filePath = line.substring(delimiterPos + 1);
127            File file = new File(filePath);
128            if (!file.exists()) {
129                Slog.i(logTag, "Failed checksum test for file: " + file + ": file not found");
130                return false;
131            }
132            long actualChecksum = FileUtils.calculateChecksum(file);
133            if (actualChecksum != expectedChecksum) {
134                Slog.i(logTag, "Failed checksum test for file: " + file
135                        + ": required=" + expectedChecksum + ", actual=" + actualChecksum);
136                return false;
137            }
138        }
139        return true;
140    }
141}
142