content: /*
   * Copyright (C) 2016 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.android.server.pm;
  
  import android.app.admin.SecurityLog;
  import android.content.Intent;
  import android.os.Bundle;
  import android.os.Handler;
  import android.os.Message;
  
  import com.android.internal.os.BackgroundThread;
  
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.security.MessageDigest;
  import java.security.NoSuchAlgorithmException;
  import java.util.HashMap;
  import android.util.Slog;
  
  public final class ProcessLoggingHandler extends Handler {
  
      private static final String TAG = "ProcessLoggingHandler";
      static final int LOG_APP_PROCESS_START_MSG = 1;
      static final int INVALIDATE_BASE_APK_HASH_MSG = 2;
  
      private final HashMap<String, String> mProcessLoggingBaseApkHashes = new HashMap();
  
      ProcessLoggingHandler() {
          super(BackgroundThread.getHandler().getLooper());
      }
  
      @Override
      public void handleMessage(Message msg) {
          switch (msg.what) {
              case LOG_APP_PROCESS_START_MSG: {
                  Bundle bundle = msg.getData();
                  String processName = bundle.getString("processName");
                  int uid = bundle.getInt("uid");
                  String seinfo = bundle.getString("seinfo");
                  String apkFile = bundle.getString("apkFile");
                  int pid = bundle.getInt("pid");
                  long startTimestamp = bundle.getLong("startTimestamp");
                  String apkHash = computeStringHashOfApk(apkFile);
                  SecurityLog.writeEvent(SecurityLog.TAG_APP_PROCESS_START, processName,
                          startTimestamp, uid, pid, seinfo, apkHash);
                  break;
              }
              case INVALIDATE_BASE_APK_HASH_MSG: {
                  Bundle bundle = msg.getData();
                  mProcessLoggingBaseApkHashes.remove(bundle.getString("apkFile"));
                  break;
              }
          }
      }
  
      void invalidateProcessLoggingBaseApkHash(String apkPath) {
          Bundle data = new Bundle();
          data.putString("apkFile", apkPath);
          Message msg = obtainMessage(INVALIDATE_BASE_APK_HASH_MSG);
          msg.setData(data);
          sendMessage(msg);
      }
  
      private String computeStringHashOfApk(String apkFile) {
          if (apkFile == null) {
              return "No APK";
          }
          String apkHash = mProcessLoggingBaseApkHashes.get(apkFile);
          if (apkHash == null) {
              try {
                  byte[] hash = computeHashOfApkFile(apkFile);
                  StringBuilder sb = new StringBuilder();
                  for (int i = 0; i < hash.length; i++) {
                      sb.append(String.format("%02x", hash[i]));
                  }
                  apkHash = sb.toString();
                  mProcessLoggingBaseApkHashes.put(apkFile, apkHash);
              } catch (IOException | NoSuchAlgorithmException e) {
                  Slog.w(TAG, "computeStringHashOfApk() failed", e);
              }
          }
          return apkHash != null ? apkHash : "Failed to count APK hash";
      }
  
      private byte[] computeHashOfApkFile(String packageArchiveLocation)
              throws IOException, NoSuchAlgorithmException {
          MessageDigest md = MessageDigest.getInstance("SHA-256");
          FileInputStream input = new FileInputStream(new File(packageArchiveLocation));
          byte[] buffer = new byte[65536];
          int size;
          while ((size = input.read(buffer)) > 0) {
              md.update(buffer, 0, size);
          }
          input.close();
          return md.digest();
      }
  }
  