libjava/java/io/FilePermission.java

   1 /* java.lang.FilePermission
   2    Copyright (C) 1998, 2000 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package java.io;
  40
  41 import java.security.*;
  42
  43
  44 public final class FilePermission extends Permission implements Serializable
  45 {
  46   static final long serialVersionUID = 7930732926638008763L;
  47
  48   private static final String CURRENT_DIRECTORY = System.getProperty("user.dir");
  49   private boolean usingPerms = false;
  50   private boolean readPerm = false;
  51   private boolean writePerm = false;
  52   private boolean executePerm = false;
  53   private boolean deletePerm = false;
  54   private String actionsString;
  55
  56   private void cachePerms() {
  57     // While race conditions could occur, they don't matter at all.
  58
  59     String action;
  60     int i = actionsString.indexOf(',');
  61     int startI = 0;
  62     while(i != -1) {
  63       action = actionsString.substring(startI,i);
  64       if(action.equals("read"))
  65         readPerm = true;
  66       else if(action.equals("write"))
  67         writePerm = true;
  68       else if(action.equals("execute"))
  69         executePerm = true;
  70       else if(action.equals("delete"))
  71         deletePerm = true;
  72
  73       startI = i+1;
  74       i = actionsString.indexOf(',',startI);
  75     }
  76
  77     action = actionsString.substring(startI);
  78     if(action.equals("read"))
  79       readPerm = true;
  80     else if(action.equals("write"))
  81       writePerm = true;
  82     else if(action.equals("execute"))
  83       executePerm = true;
  84     else if(action.equals("delete"))
  85       deletePerm = true;
  86   }
  87
  88   /** Create a new FilePermission.
  89    ** @param pathExpression an expression specifying the paths this
  90    **        permission represents.
  91    ** @param actionsString a comma-separated list of the actions this
  92    **        permission represents.
  93    ** @XXX what to do when the file string is malformed?
  94    **/
  95   public FilePermission(String pathExpression, String actionsString)
  96     {
  97       super(pathExpression);
  98       this.actionsString = actionsString;
  99     }
 100
 101   /** Get the actions this FilePermission supports.
 102    ** @return the String representing the actions this FilePermission supports.
 103    **/
 104   public String getActions() {
 105     return actionsString;
 106   }
 107
 108   /** Get the hash code for this Object.<P>
 109    ** FilePermission's hash code is calculated as the exclusive or of the target
 110    ** String's hash code and the action String's hash code.
 111    ** @specnote Sun did not specify how to calculate the hash code; I made this up.
 112    ** @return the hash code for this Object.
 113    **/
 114   public int hashCode() {
 115     return getName().hashCode() ^ actionsString.hashCode();
 116   }
 117
 118   /** Check two FilePermissions for semantic equality.
 119    ** Two FilePermissions are exactly equivalent if they have identical path
 120    ** expressions and have exactly the same access permissions.
 121    ** @param o the Object to compare to.
 122    ** @return whether the Objects are semantically equivalent.
 123    **/
 124   public boolean equals(Object o) {
 125     if(!(o instanceof FilePermission))
 126       return false;
 127     FilePermission p = (FilePermission)o;
 128     if(!usingPerms)
 129       cachePerms();
 130     if(!p.usingPerms)
 131       p.cachePerms();
 132
 133     String f1 = getName();
 134     String f2 = p.getName();
 135
 136     /* Compare names, taking into account if they refer to a
 137      * directory and one has a separator and the other does not.
 138      */
 139     if(f1.charAt(f1.length()) == File.separatorChar) {
 140       if(f2.charAt(f2.length()) == File.separatorChar) {
 141         if(!f2.equals(f1))
 142           return false;
 143       } else {
 144         if(!f2.equals(f1.substring(0,f1.length()-1)))
 145           return false;
 146       }
 147     } else {
 148       if(f2.charAt(f2.length()) == File.separatorChar) {
 149         if(!f1.equals(f2.substring(0,f2.length()-1)))
 150           return false;
 151       } else {
 152         if(!f1.equals(f2))
 153           return false;
 154       }
 155     }
 156     return readPerm == p.readPerm && writePerm == p.writePerm && executePerm == p.executePerm && deletePerm == p.deletePerm;
 157   }
 158
 159   /** Check to see if this permission implies another.
 160    ** Permission A implies permission B if these things are all true:
 161    ** <OL>
 162    ** <LI>A and B are both FilePermissions.</LI>
 163    ** <LI>All possible files in B are included in A (possibly more are in A).</LI>
 164    ** <LI>All actions B supports, A also supports.</LI>
 165    ** </OL>
 166    ** @param p the Permission to compare against.
 167    ** @return whether this Permission implies p
 168    **/
 169   public boolean implies(Permission p) {
 170     FilePermission fp;
 171     if(!(p instanceof FilePermission))
 172       return false;
 173     fp = (FilePermission)p;
 174
 175     String f1 = getName();
 176     String f2 = fp.getName();
 177     if(f1.charAt(0) != File.separatorChar) {
 178       f1 = CURRENT_DIRECTORY + f1;
 179     }
 180     if(f2.charAt(0) != File.separatorChar) {
 181       f2 = CURRENT_DIRECTORY + f2;
 182     }
 183
 184     String sub1, sub2a, sub2b;
 185     switch(f1.charAt(f1.length() - 1)) {
 186     case '*':
 187       sub1 = f1.substring(0,f1.length() - 1); // chop off "*"
 188       if(f2.length() <= sub1.length()) {
 189         /* If it's smaller, there is no way it could be part of this directory.
 190          * If it's the same (or length - 1), it could be the same directory but
 191          * specifies access to the directory rather than the files in it.
 192          */
 193         return false;
 194       } else if(f2.charAt(sub1.length() - 1) == File.separatorChar) {
 195         /* Make sure the part before the "/" is the same */
 196         if(!f2.substring(0,sub1.length()).equals(sub1))
 197           return false;
 198         /* Make sure there are no subdirectories specified underneath this one */
 199         String sub2 = f2.substring(sub1.length()+1);
 200         if(f2.substring(sub1.length()+1).indexOf(File.separatorChar) != -1)
 201           return false;
 202       } else {
 203         /* Obviously not equal: f2 is either not a directory or is not
 204          * the same directory (its name continues further than we want)
 205          */
 206         return false;
 207       }
 208       break;
 209     case '-':
 210       sub1 = f1.substring(0,f1.length() - 2); // chop off "/-"
 211       if(f2.length() < sub1.length()) {
 212         /* If it's smaller, there is no way it could be part of this directory. */
 213         return false;
 214       } else if(f2.length() > sub1.length() && f2.charAt(sub1.length()) != File.separatorChar) {
 215         return false;
 216       } else if(!f2.substring(0,sub1.length()).equals(sub1))
 217         return false;
 218       break;
 219 /* Looks redundant with default case and won't compile anyway - arenn
 220     case File.separatorChar:
 221       if(f2.charAt(f2.length()) == File.separatorChar) {
 222         if(!f2.equals(f1))
 223           return false;
 224       } else {
 225         if(!f2.equals(f1.substring(0,f1.length()-1)))
 226           return false;
 227       }
 228       break;
 229 */
 230     default:
 231       if(f2.charAt(f2.length()) == File.separatorChar) {
 232         if(!f1.equals(f2.substring(0,f2.length()-1)))
 233           return false;
 234       } else {
 235         if(!f1.equals(f2))
 236           return false;
 237       }
 238       break;
 239     }
 240
 241     if(!usingPerms)
 242       cachePerms();
 243     if(!fp.usingPerms)
 244       fp.cachePerms();
 245
 246     if(readPerm && !fp.readPerm)
 247       return false;
 248     if(writePerm && !fp.writePerm)
 249       return false;
 250     if(executePerm && !fp.executePerm)
 251       return false;
 252     if(deletePerm && !fp.deletePerm)
 253       return false;
 254
 255     return true;
 256   }
 257 }