1 /*
   2  * Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.nio.file;
  27 
  28 import java.security.BasicPermission;
  29 
  30 /**
  31  * The {@code Permission} class for link creation operations.
  32  *
  33  * <p> The following table provides a summary description of what the permission
  34  * allows, and discusses the risks of granting code the permission.
  35  *
  36  * <table border=1 cellpadding=5
  37  *        summary="Table shows permission target name, what the permission allows, and associated risks">
  38  * <tr>
  39  * <th>Permission Target Name</th>
  40  * <th>What the Permission Allows</th>
  41  * <th>Risks of Allowing this Permission</th>
  42  * </tr>
  43  * <tr>
  44  *   <td>hard</td>
  45  *   <td> Ability to add an existing file to a directory. This is sometimes
  46  *   known as creating a link, or hard link. </td>
  47  *   <td> Extreme care should be taken when granting this permission. It allows
  48  *   linking to any file or directory in the file system thus allowing the
  49  *   attacker access to all files. </td>
  50  * </tr>
  51  * <tr>
  52  *   <td>symbolic</td>
  53  *   <td> Ability to create symbolic links. </td>
  54  *   <td> Extreme care should be taken when granting this permission. It allows
  55  *   linking to any file or directory in the file system thus allowing the
  56  *   attacker to access to all files. </td>
  57  * </tr>
  58  * </table>
  59  *
  60  * @since 1.7
  61  *
  62  * @see Files#createLink
  63  * @see Files#createSymbolicLink
  64  */
  65 public final class LinkPermission extends BasicPermission {
  66     static final long serialVersionUID = -1441492453772213220L;
  67 
  68     private void checkName(String name) {
  69         if (!name.equals("hard") && !name.equals("symbolic")) {
  70             throw new IllegalArgumentException("name: " + name);
  71         }
  72     }
  73 
  74     /**
  75      * Constructs a {@code LinkPermission} with the specified name.
  76      *
  77      * @param   name
  78      *          the name of the permission. It must be "hard" or "symbolic".
  79      *
  80      * @throws  IllegalArgumentException
  81      *          if name is empty or invalid
  82      */
  83     public LinkPermission(String name) {
  84         super(name);
  85         checkName(name);
  86     }
  87 
  88     /**
  89      * Constructs a {@code LinkPermission} with the specified name.
  90      *
  91      * @param   name
  92      *          the name of the permission; must be "hard" or "symbolic".
  93      * @param   actions
  94      *          the actions for the permission; must be the empty string or
  95      *          {@code null}
  96      *
  97      * @throws  IllegalArgumentException
  98      *          if name is empty or invalid, or actions is a non-empty string
  99      */
 100     public LinkPermission(String name, String actions) {
 101         super(name);
 102         checkName(name);
 103         if (actions != null && actions.length() > 0) {
 104             throw new IllegalArgumentException("actions: " + actions);
 105         }
 106     }
 107 }