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Java > Open Source Codes > org > apache > avalon > phoenix > components > classloader > AbstractPolicy


1 /*
2  * Copyright (C) The Apache Software Foundation. All rights reserved.
3  *
4  * This software is published under the terms of the Apache Software License
5  * version 1.1, a copy of which has been included with this distribution in
6  * the LICENSE.txt file.
7  */
8 package org.apache.avalon.phoenix.components.classloader;
9
10 import java.io.File;
11 import java.net.MalformedURLException;
12 import java.net.URL;
13 import java.security.CodeSource;
14 import java.security.Permission;
15 import java.security.PermissionCollection;
16 import java.security.Permissions;
17 import java.security.Policy;
18 import java.security.cert.Certificate;
19 import java.util.ArrayList;
20 import java.util.Enumeration;
21 import org.apache.avalon.excalibur.io.FileUtil;
22 import org.apache.avalon.framework.logger.LogEnabled;
23 import org.apache.avalon.framework.logger.Logger;
24
25 /**
26  * Abstract policy extended in avalon.
27  *
28  * @author <a HREF="mailto:peter at apache.org">Peter Donald</a>
29  */
30 abstract class AbstractPolicy
31     extends Policy
32     implements LogEnabled
33 {
34     private final ArrayList m_entries = new ArrayList();
35
36     private Logger m_logger;
37
38     public void enableLogging( final Logger logger )
39     {
40         m_logger = logger;
41     }
42
43     /**
44      * Overide so we can have a per-application security policy with
45      * no side-effects to other applications.
46      *
47      * @param codeSource the codeSource to get permissions for
48      * @return the PermissionCollection
49      */
50     public PermissionCollection getPermissions( CodeSource codeSource )
51     {
52         codeSource = normalize( codeSource );
53
54         if( getLogger().isDebugEnabled() )
55         {
56             getLogger().debug( "getPermissions(" + codeSource.getLocation() + ");" );
57         }
58
59         final Permissions permissions = new Permissions();
60         final int size = m_entries.size();
61
62         for( int i = 0; i < size; i++ )
63         {
64             final PolicyEntry entry = (PolicyEntry)m_entries.get( i );
65             if( entry.getCodeSource().implies( codeSource ) )
66             {
67                 copyPermissions( permissions, entry.getPermissions() );
68             }
69         }
70
71         return permissions;
72     }
73
74     /**
75      * Refresh policy. Ignored in this implementation.
76      */
77     public void refresh()
78     {
79     }
80
81     /**
82      * Create a permission set for a codeBase.
83      * These are read-write permissions and can be written till until the
84      * time in which they are applied to code.
85      *
86      * @param location the location of codes to apply permission set to.
87      * @param signers a comma seperated string of thos who signed codebase
88      * @return the new permission set
89      * @throws MalformedURLException if location string is malformed
90      */
91     protected Permissions createPermissionSetFor( final String location,
92                                                   final Certificate[] signers )
93         throws MalformedURLException
94     {
95         return createPermissionSetFor( new URL( location ), signers );
96     }
97
98     protected Permissions createPermissionSetFor( final URL url,
99                                                   final Certificate[] signers )
100     {
101         getLogger().debug( "createPermissionSetFor(" + url + ");" );
102
103         CodeSource codeSource = new CodeSource( url, signers );
104         codeSource = normalize( codeSource );
105         final PolicyEntry entry = new PolicyEntry( codeSource, new Permissions() );
106         m_entries.add( entry );
107         return entry.getPermissions();
108     }
109
110     protected final Logger getLogger()
111     {
112         return m_logger;
113     }
114
115     /**
116      * Normalizing CodeSource involves removing relative addressing
117      * (like .. and .) for file urls.
118      *
119      * @param codeSource the codeSource to be normalized
120      * @return the normalized codeSource
121      */
122     private CodeSource normalize( final CodeSource codeSource )
123     {
124         final URL initialLocation = codeSource.getLocation();
125
126         // This is a bit of a hack. I don't know why CodeSource should behave like this
127 // Fear not, this only seems to be a problem for home grown classloaders.
128 // - Paul Hammant, Nov 2000
129 if( null == initialLocation )
130         {
131             return codeSource;
132         }
133
134         String location = null;
135
136         if( !initialLocation.getProtocol().equalsIgnoreCase( "file" ) )
137         {
138             location = initialLocation.getFile();
139             location = FileUtil.normalize( location );
140         }
141         else
142         {
143             final File file = new File( initialLocation.getFile() );
144             location = file.getAbsoluteFile().toString().replace( File.separatorChar, '/' );
145             location = FileUtil.normalize( location );
146         }
147
148         URL finalLocation = null;
149
150         try
151         {
152             finalLocation = new URL( initialLocation.getProtocol(),
153                                      initialLocation.getHost(),
154                                      initialLocation.getPort(),
155                                      location );
156         }
157         catch( final MalformedURLException mue )
158         {
159             getLogger().warn( "Error building codeBase", mue );
160         }
161
162         return new CodeSource( finalLocation, codeSource.getCertificates() );
163     }
164
165     /**
166      * Utility method to cpoy permissions from specified source to specified destination.
167      *
168      * @param destination the destination of permissions
169      * @param source the source of permissions
170      */
171     private void copyPermissions( final Permissions destination,
172                                   final Permissions source )
173     {
174         final Enumeration enum = source.elements();
175         while( enum.hasMoreElements() )
176         {
177             destination.add( (Permission)enum.nextElement() );
178         }
179     }
180 }
181
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