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13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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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 
checkName(String name)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      */
LinkPermission(String name)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      */
LinkPermission(String name, String actions)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 }
108