/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.sentry.binding.hive;

import org.apache.hadoop.hive.conf.HiveConf;
import org.apache.hadoop.hive.conf.HiveConf.ConfVars;
import org.apache.hive.service.cli.HiveSQLException;
import org.apache.hive.service.cli.session.HiveSessionHookContext;
import org.apache.sentry.binding.hive.conf.HiveAuthzConf;

public class HiveAuthzBindingSessionHook
    implements org.apache.hive.service.cli.session.HiveSessionHook {

  public static final String SEMANTIC_HOOK =
    "org.apache.sentry.binding.hive.HiveAuthzBindingHook";
  public static final String PRE_EXEC_HOOK =
    "org.apache.sentry.binding.hive.HiveAuthzBindingPreExecHook";
  public static final String FILTER_HOOK =
    "org.apache.sentry.binding.hive.HiveAuthzBindingHook";
  public static final String SCRATCH_DIR_PERMISSIONS = "700";
  public static final String ACCESS_RESTRICT_LIST =
    ConfVars.SEMANTIC_ANALYZER_HOOK.varname + "," +
    ConfVars.PREEXECHOOKS.varname + "," +
    ConfVars.HIVE_EXEC_FILTER_HOOK.varname + "," +
    ConfVars.HIVE_EXTENDED_ENITITY_CAPTURE.varname + "," +
    ConfVars.SCRATCHDIR.varname + "," +
    ConfVars.LOCALSCRATCHDIR.varname + "," +
    ConfVars.HIVE_SERVER2_AUTHZ_EXTERNAL_EXEC.varname + "," +
    ConfVars.METASTOREURIS.varname + "," +
    ConfVars.METASTORECONNECTURLKEY.varname + "," +
    ConfVars.HADOOPBIN.varname + "," +
    ConfVars.HIVESESSIONID.varname + "," +
    ConfVars.HIVEAUXJARS.varname + "," +
    ConfVars.HIVESTATSDBCONNECTIONSTRING.varname + "," +
    ConfVars.SCRATCHDIRPERMISSION.varname + "," +
    HiveAuthzConf.HIVE_ACCESS_CONF_URL + "," +
    HiveAuthzConf.HIVE_SENTRY_CONF_URL + "," +
    HiveAuthzConf.HIVE_ACCESS_SUBJECT_NAME + "," +
    HiveAuthzConf.HIVE_SENTRY_SUBJECT_NAME;

  /**
   * The session hook for sentry authorization that sets the required session level configuration
   * 1. Setup the sentry hooks -
   *    semantic, exec and filter hooks
   * 2. Set additional config properties required for auth
   *      set HIVE_EXTENDED_ENITITY_CAPTURE = true
   *      set HIVE_SERVER2_AUTHZ_EXTERNAL_EXEC = false
   *      set SCRATCHDIRPERMISSION = 700
   * 3. Add sensetive config parameters to the config restrict list so that they can't be overridden by users
   */
  @Override
  public void run(HiveSessionHookContext sessionHookContext) throws HiveSQLException {
    // Add sentry hooks to the session configuration
    HiveConf sessionConf = sessionHookContext.getSessionConf();

    appendConfVar(sessionConf, ConfVars.SEMANTIC_ANALYZER_HOOK, SEMANTIC_HOOK);
    appendConfVar(sessionConf, ConfVars.PREEXECHOOKS, PRE_EXEC_HOOK);
    appendConfVar(sessionConf, ConfVars.HIVE_EXEC_FILTER_HOOK, FILTER_HOOK);

    // setup config
    sessionConf.setBoolVar(ConfVars.HIVE_EXTENDED_ENITITY_CAPTURE, true);
    sessionConf.setBoolVar(ConfVars.HIVE_SERVER2_AUTHZ_EXTERNAL_EXEC, false);
    sessionConf.setVar(ConfVars.SCRATCHDIRPERMISSION, SCRATCH_DIR_PERMISSIONS);

    // set user name
    sessionConf.set(HiveAuthzConf.HIVE_ACCESS_SUBJECT_NAME, sessionHookContext.getSessionUser());
    sessionConf.set(HiveAuthzConf.HIVE_SENTRY_SUBJECT_NAME, sessionHookContext.getSessionUser());

    // setup restrict list
    sessionConf.addToRestrictList(ACCESS_RESTRICT_LIST);
  }

  // Setup given sentry hooks
  private void appendConfVar(HiveConf sessionConf, ConfVars confVar, String sentryConfVal) {
    String currentValue = sessionConf.getVar(confVar);
    if ((currentValue == null) || currentValue.isEmpty()) {
      currentValue = sentryConfVal;
    } else {
      currentValue = sentryConfVal + "," + currentValue;
    }
    sessionConf.setVar(confVar, currentValue);
  }
}