Source for java.security.ProtectionDomain

   1: /* ProtectionDomain.java -- A security domain
   2:    Copyright (C) 1998, 2003, 2004  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., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 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: package java.security;
  39: 
  40: /**
  41:  * <p>This <code>ProtectionDomain</code> class encapsulates the characteristics
  42:  * of a domain, which encloses a set of classes whose instances are granted a
  43:  * set of permissions when being executed on behalf of a given set of
  44:  * <i>Principals</i>.
  45:  *
  46:  * <p>A static set of permissions can be bound to a <code>ProtectionDomain</code>
  47:  * when it is constructed; such permissions are granted to the domain regardless
  48:  * of the {@link Policy} in force. However, to support dynamic security
  49:  * policies, a <code>ProtectionDomain</code> can also be constructed such that
  50:  * it is dynamically mapped to a set of permissions by the current {@link
  51:  * Policy} whenever a permission is checked.</p>
  52:  *
  53:  * @author Aaron M. Renn (arenn@urbanophile.com)
  54:  * @version 0.0
  55:  */
  56: public class ProtectionDomain
  57: {
  58:   /** This is the <code>CodeSource</code> for this protection domain. */
  59:   private CodeSource code_source;
  60: 
  61:   /** This is the set of permissions granted to this domain. */
  62:   private PermissionCollection perms;
  63: 
  64:   /** The {@link ClassLoader} associated with this domain. */
  65:   private ClassLoader classloader;
  66: 
  67:   /** The array of Principals associated with this domain.. */
  68:   private Principal[] principals;
  69: 
  70:   /** Post 1.4 the policy may be refreshed! use false for pre 1.4. */
  71:   private boolean staticBinding;
  72: 
  73:   /**
  74:    * Creates a new <code>ProtectionDomain</code> with the given {@link
  75:    * CodeSource} and {@link Permissions}. If the permissions object is not
  76:    * <code>null</code>, then <code>setReadOnly()</code> will be called on the
  77:    * passed in {@link Permissions} object. The only permissions granted to this
  78:    * domain are the ones specified; the current {@link Policy} will not be
  79:    * consulted.
  80:    *
  81:    * @param codesource the codesource associated with this domain.
  82:    * @param permissions the permissions granted to this domain
  83:    */
  84:   public ProtectionDomain(CodeSource codesource, PermissionCollection permissions)
  85:   {
  86:     this(codesource, permissions, null, null, true);
  87:   }
  88: 
  89:   /**
  90:    * <p>Creates a new ProtectionDomain qualified by the given CodeSource,
  91:    * Permissions, ClassLoader and array of Principals. If the permissions
  92:    * object is not null, then <code>setReadOnly()</code> will be called on the
  93:    * passed in Permissions object. The permissions granted to this domain are
  94:    * dynamic; they include both the static permissions passed to this
  95:    * constructor, and any permissions granted to this domain by the current
  96:    * Policy at the time a permission is checked.</p>
  97:    *
  98:    * <p>This constructor is typically used by {@link ClassLoader}s and {@link
  99:    * DomainCombiner}s which delegate to <code>Policy</code> to actively
 100:    * associate the permissions granted to this domain. This constructor affords
 101:    * the Policy provider the opportunity to augment the supplied
 102:    * PermissionCollection to reflect policy changes.</p>
 103:    *
 104:    * @param codesource the CodeSource associated with this domain.
 105:    * @param permissions the permissions granted to this domain.
 106:    * @param classloader the ClassLoader associated with this domain.
 107:    * @param principals the array of Principals associated with this domain.
 108:    * @since 1.4
 109:    * @see Policy#refresh()
 110:    * @see Policy#getPermissions(ProtectionDomain)
 111:   */
 112:   public ProtectionDomain(CodeSource codesource,
 113:                           PermissionCollection permissions,
 114:                           ClassLoader classloader, Principal[] principals)
 115:   {
 116:     this(codesource, permissions, classloader, principals, false);
 117:   }
 118: 
 119:   private ProtectionDomain(CodeSource codesource,
 120:                            PermissionCollection permissions,
 121:                            ClassLoader classloader, Principal[] principals,
 122:                            boolean staticBinding)
 123:   {
 124:     super();
 125: 
 126:     code_source = codesource;
 127:     if (permissions != null)
 128:       {
 129:         perms = permissions;
 130:         perms.setReadOnly();
 131:       }
 132: 
 133:     this.classloader = classloader;
 134:     this.principals =
 135:         (principals != null ? (Principal[]) principals.clone() : new Principal[0]);
 136:     this.staticBinding = staticBinding;
 137:   }
 138: 
 139:   /**
 140:    * Returns the {@link CodeSource} of this domain.
 141:    *
 142:    * @return the {@link CodeSource} of this domain which may be <code>null</code>.
 143:    * @since 1.2
 144:    */
 145:   public final CodeSource getCodeSource()
 146:   {
 147:     return code_source;
 148:   }
 149: 
 150:   /**
 151:    * Returns the {@link ClassLoader} of this domain.
 152:    *
 153:    * @return the {@link ClassLoader} of this domain which may be
 154:    * <code>null</code>.
 155:    * @since 1.4
 156:    */
 157:   public final ClassLoader getClassLoader()
 158:   {
 159:     return this.classloader;
 160:   }
 161: 
 162:   /**
 163:    * Returns an array of principals for this domain.
 164:    *
 165:    * @return returns a non-null array of principals for this domain. Changes to
 166:    * this array will have no impact on the <code>ProtectionDomain</code>.
 167:    * @since 1.4
 168:    */
 169:   public final Principal[] getPrincipals()
 170:   {
 171:     return (Principal[]) principals.clone();
 172:   }
 173: 
 174:   /**
 175:    * Returns the static permissions granted to this domain.
 176:    *
 177:    * @return the static set of permissions for this domain which may be
 178:    * <code>null</code>.
 179:    * @see Policy#refresh()
 180:    * @see Policy#getPermissions(ProtectionDomain)
 181:    */
 182:   public final PermissionCollection getPermissions()
 183:   {
 184:     return perms;
 185:   }
 186: 
 187:   /**
 188:    * <p>Check and see if this <code>ProtectionDomain</code> implies the
 189:    * permissions expressed in the <code>Permission</code> object.</p>
 190:    *
 191:    * <p>The set of permissions evaluated is a function of whether the
 192:    * <code>ProtectionDomain</code> was constructed with a static set of
 193:    * permissions or it was bound to a dynamically mapped set of permissions.</p>
 194:    *
 195:    * <p>If the <code>ProtectionDomain</code> was constructed to a statically
 196:    * bound {@link PermissionCollection} then the permission will only be checked
 197:    * against the {@link PermissionCollection} supplied at construction.</p>
 198:    *
 199:    * <p>However, if the <code>ProtectionDomain</code> was constructed with the
 200:    * constructor variant which supports dynamically binding permissions, then
 201:    * the permission will be checked against the combination of the
 202:    * {@link PermissionCollection} supplied at construction and the current
 203:    * {@link Policy} binding.
 204:    *
 205:    * @param permission the {@link Permission} object to check.
 206:    * @return <code>true</code> if <code>permission</code> is implicit to this
 207:    * <code>ProtectionDomain</code>.
 208:    */
 209:   public boolean implies(Permission permission)
 210:   {
 211:     if (staticBinding)
 212:       return (perms == null ? false : perms.implies(permission));
 213:     // Else dynamically bound.  Do we have it?
 214:     // NOTE: this will force loading of Policy.currentPolicy
 215:     return Policy.getCurrentPolicy().implies(this, permission);
 216:   }
 217: 
 218:   /**
 219:    * Convert a <code>ProtectionDomain</code> to a String.
 220:    *
 221:    * @return a string representation of the object.
 222:    */
 223:   public String toString()
 224:   {
 225:     String linesep = System.getProperty("line.separator");
 226:     StringBuffer sb = new StringBuffer("ProtectionDomain (").append(linesep);
 227: 
 228:     if (code_source == null)
 229:       sb.append("CodeSource:null");
 230:     else
 231:       sb.append(code_source);
 232: 
 233:     sb.append(linesep);
 234:     if (classloader == null)
 235:       sb.append("ClassLoader:null");
 236:     else
 237:       sb.append(classloader);
 238: 
 239:     sb.append(linesep);
 240:     sb.append("Principals:");
 241:     if (principals != null && principals.length > 0)
 242:       {
 243:         sb.append("[");
 244:         Principal pal;
 245:         for (int i = 0; i < principals.length; i++)
 246:           {
 247:             pal = principals[i];
 248:             sb.append("'").append(pal.getName())
 249:                 .append("' of type ").append(pal.getClass().getName());
 250:             if (i < principals.length-1)
 251:               sb.append(", ");
 252:           }
 253:         sb.append("]");
 254:       }
 255:     else
 256:       sb.append("none");
 257: 
 258:     sb.append(linesep);
 259:     if (!staticBinding) // include all but dont force loading Policy.currentPolicy
 260:       if (Policy.isLoaded())
 261:         sb.append(Policy.getCurrentPolicy().getPermissions(this));
 262:       else // fallback on this one's permissions
 263:         sb.append(perms);
 264:     else
 265:       sb.append(perms);
 266: 
 267:     return sb.append(linesep).append(")").append(linesep).toString();
 268:   }
 269: }