001/* PropertyPermission.java -- permission to get and set System properties 002 Copyright (C) 1999, 2000, 2002, 2004, 2005 Free Software Foundation, Inc. 003 004This file is part of GNU Classpath. 005 006GNU Classpath is free software; you can redistribute it and/or modify 007it under the terms of the GNU General Public License as published by 008the Free Software Foundation; either version 2, or (at your option) 009any later version. 010 011GNU Classpath is distributed in the hope that it will be useful, but 012WITHOUT ANY WARRANTY; without even the implied warranty of 013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014General Public License for more details. 015 016You should have received a copy of the GNU General Public License 017along with GNU Classpath; see the file COPYING. If not, write to the 018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 01902110-1301 USA. 020 021Linking this library statically or dynamically with other modules is 022making a combined work based on this library. Thus, the terms and 023conditions of the GNU General Public License cover the whole 024combination. 025 026As a special exception, the copyright holders of this library give you 027permission to link this library with independent modules to produce an 028executable, regardless of the license terms of these independent 029modules, and to copy and distribute the resulting executable under 030terms of your choice, provided that you also meet, for each linked 031independent module, the terms and conditions of the license of that 032module. An independent module is a module which is not derived from 033or based on this library. If you modify this library, you may extend 034this exception to your version of the library, but you are not 035obligated to do so. If you do not wish to do so, delete this 036exception statement from your version. */ 037 038 039package java.util; 040 041import java.io.IOException; 042import java.io.ObjectInputStream; 043import java.io.ObjectOutputStream; 044import java.io.ObjectStreamField; 045import java.security.BasicPermission; 046import java.security.Permission; 047import java.security.PermissionCollection; 048 049/** 050 * This class represents the permission to access and modify a property.<br> 051 * 052 * The name is the name of the property, e.g. xxx. You can also 053 * use an asterisk "*" as described in BasicPermission.<br> 054 * 055 * The action string is a comma-separated list of keywords. There are 056 * two possible actions: 057 * <dl> 058 * <dt>read</dt> 059 * <dd>Allows to read the property via <code>System.getProperty</code>.</dd> 060 * <dt>write</dt> 061 * <dd>Allows to write the property via <code>System.setProperty</code>.</dd> 062 * </dl> 063 * 064 * The action string is case insensitive (it is converted to lower case). 065 * 066 * @see Permission 067 * @see BasicPermission 068 * @see SecurityManager 069 * @author Jochen Hoenicke 070 * @since 1.2 071 * @status updated to 1.4 072 */ 073public final class PropertyPermission extends BasicPermission 074{ 075 /** 076 * PropertyPermission uses a more efficient representation than the 077 * serialized form; this documents the difference. 078 * 079 * @serialField action String the action string 080 */ 081 private static final ObjectStreamField[] serialPersistentFields = 082 { 083 new ObjectStreamField("action", String.class) 084 }; 085 086 /** 087 * Compatible with JDK 1.2+. 088 */ 089 private static final long serialVersionUID = 885438825399942851L; 090 091 /** Permission to read. */ 092 private static final int READ = 1; 093 /** Permission to write. */ 094 private static final int WRITE = 2; 095 096 /** The set of actions permitted. */ 097 // Package visible for use by PropertyPermissionCollection. 098 transient int actions; 099 100 /** 101 * The String forms of the actions permitted. 102 */ 103 private static final String actionStrings[] = 104 { 105 "", "read", "write", "read,write" 106 }; 107 108 /** 109 * Constructs a PropertyPermission with the specified property. Possible 110 * actions are read and write, comma-separated and case-insensitive. 111 * 112 * @param name the name of the property 113 * @param actions the action string 114 * @throws NullPointerException if name is null 115 * @throws IllegalArgumentException if name string contains an 116 * illegal wildcard or actions string contains an illegal action 117 * (this includes a null actions string) 118 */ 119 public PropertyPermission(String name, String actions) 120 { 121 super(name); 122 if (actions == null) 123 throw new IllegalArgumentException(); 124 setActions(actions); 125 } 126 127 /** 128 * Parse the action string and convert actions from external to internal 129 * form. This will set the internal actions field. 130 * 131 * @param str the action string 132 * @throws IllegalArgumentException if actions string contains an 133 * illegal action 134 */ 135 private void setActions(String str) 136 { 137 // Initialising the class java.util.Locale ... 138 // tries to initialise the Locale.defaultLocale static 139 // which calls System.getProperty, 140 // which calls SecurityManager.checkPropertiesAccess, 141 // which creates a PropertyPermission with action "read,write", 142 // which calls setActions("read,write"). 143 // If we now were to call toLowerCase on 'str', 144 // this would call Locale.getDefault() which returns null 145 // because Locale.defaultLocale hasn't been set yet 146 // then toLowerCase will fail with a null pointer exception. 147 // 148 // The solution is to take a punt on 'str' being lower case, and 149 // test accordingly. If that fails, we convert 'str' to lower case 150 // and try the tests again. 151 if ("read".equals(str)) 152 actions = READ; 153 else if ("write".equals(str)) 154 actions = WRITE; 155 else if ("read,write".equals(str) || "write,read".equals(str)) 156 actions = READ | WRITE; 157 else 158 { 159 String lstr = str.toLowerCase(); 160 if ("read".equals(lstr)) 161 actions = READ; 162 else if ("write".equals(lstr)) 163 actions = WRITE; 164 else if ("read,write".equals(lstr) || "write,read".equals(lstr)) 165 actions = READ | WRITE; 166 else 167 throw new IllegalArgumentException("illegal action " + str); 168 } 169 } 170 171 /** 172 * Reads an object from the stream. This converts the external to the 173 * internal representation. 174 * 175 * @param s the stream to read from 176 * @throws IOException if the stream fails 177 * @throws ClassNotFoundException if reserialization fails 178 */ 179 private void readObject(ObjectInputStream s) 180 throws IOException, ClassNotFoundException 181 { 182 ObjectInputStream.GetField fields = s.readFields(); 183 setActions((String) fields.get("actions", null)); 184 } 185 186 /** 187 * Writes an object to the stream. This converts the internal to the 188 * external representation. 189 * 190 * @param s the stram to write to 191 * @throws IOException if the stream fails 192 */ 193 private void writeObject(ObjectOutputStream s) throws IOException 194 { 195 ObjectOutputStream.PutField fields = s.putFields(); 196 fields.put("actions", getActions()); 197 s.writeFields(); 198 } 199 200 /** 201 * Check if this permission implies p. This returns true iff all of 202 * the following conditions are true: 203 * <ul> 204 * <li> p is a PropertyPermission </li> 205 * <li> this.getName() implies p.getName(), 206 * e.g. <code>java.*</code> implies <code>java.home</code> </li> 207 * <li> this.getActions is a subset of p.getActions </li> 208 * </ul> 209 * 210 * @param p the permission to check 211 * @return true if this permission implies p 212 */ 213 public boolean implies(Permission p) 214 { 215 // BasicPermission checks for name and type. 216 if (super.implies(p)) 217 { 218 // We have to check the actions. 219 PropertyPermission pp = (PropertyPermission) p; 220 return (pp.actions & ~actions) == 0; 221 } 222 return false; 223 } 224 225 /** 226 * Check to see whether this object is the same as another 227 * PropertyPermission object; this is true if it has the same name and 228 * actions. 229 * 230 * @param obj the other object 231 * @return true if the two are equivalent 232 */ 233 public boolean equals(Object obj) 234 { 235 return super.equals(obj) && actions == ((PropertyPermission) obj).actions; 236 } 237 238 /** 239 * Returns the hash code for this permission. It is equivalent to 240 * <code>getName().hashCode()</code>. 241 * 242 * @return the hash code 243 */ 244 public int hashCode() 245 { 246 return super.hashCode(); 247 } 248 249 /** 250 * Returns the action string. Note that this may differ from the string 251 * given at the constructor: The actions are converted to lowercase and 252 * may be reordered. 253 * 254 * @return one of "read", "write", or "read,write" 255 */ 256 public String getActions() 257 { 258 return actionStrings[actions]; 259 } 260 261 /** 262 * Returns a permission collection suitable to take 263 * PropertyPermission objects. 264 * 265 * @return a new empty PermissionCollection 266 */ 267 public PermissionCollection newPermissionCollection() 268 { 269 return new PropertyPermissionCollection(); 270 } 271}