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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.commons.net.examples.mail;
19  
20  import java.io.BufferedReader;
21  import java.io.Console;
22  import java.io.IOException;
23  import java.io.InputStreamReader;
24  import java.util.Locale;
25  
26  /**
27   * Utilities for mail examples
28   */
29  class Utils {
30  
31      private Utils() {
32          // not instantiable
33      }
34  
35      /**
36       * If the initial password is:
37       * '*' - replace it with a line read from the system console
38       * '-' - replace it with next line from STDIN
39       * 'ABCD' - if the input is all upper case, use the field as an environment variable name
40       *
41       * Note: there are no guarantees that the password cannot be snooped.
42       *
43       * Even using the console may be subject to memory snooping,
44       * however it should be safer than the other methods.
45       *
46       * STDIN may require creating a temporary file which could be read by others
47       * Environment variables may be visible by using PS
48       */
49      static String getPassword(final String username, String password) throws IOException {
50          if ("-".equals(password)) { // stdin
51              final BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
52              password = in.readLine();
53          } else if ("*".equals(password)) { // console
54              final Console con = System.console(); // Java 1.6
55              if (con != null) {
56                  final char[] pwd = con.readPassword("Password for " + username + ": ");
57                  password = new String(pwd);
58              } else {
59                  throw new IOException("Cannot access Console");
60              }
61          } else if (password.equals(password.toUpperCase(Locale.ROOT))) { // environment variable name
62              final String tmp = System.getenv(password);
63              if (tmp != null) { // don't overwrite if variable does not exist (just in case password is all uppers)
64                  password=tmp;
65              }
66          }
67          return password;
68      }
69  
70  }