J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2003-2005 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package sun.instrument; |
| 27 | |
| 28 | |
| 29 | import java.lang.instrument.Instrumentation; |
| 30 | import java.lang.instrument.ClassFileTransformer; |
| 31 | import java.security.ProtectionDomain; |
| 32 | |
| 33 | /* |
| 34 | * Copyright 2003 Wily Technology, Inc. |
| 35 | */ |
| 36 | |
| 37 | /** |
| 38 | * Support class for the InstrumentationImpl. Manages the list of registered transformers. |
| 39 | * Keeps everything in the right order, deals with sync of the list, |
| 40 | * and actually does the calling of the transformers. |
| 41 | */ |
| 42 | public class TransformerManager |
| 43 | { |
| 44 | private class TransformerInfo { |
| 45 | final ClassFileTransformer mTransformer; |
| 46 | String mPrefix; |
| 47 | |
| 48 | TransformerInfo(ClassFileTransformer transformer) { |
| 49 | mTransformer = transformer; |
| 50 | mPrefix = null; |
| 51 | } |
| 52 | |
| 53 | ClassFileTransformer transformer() { |
| 54 | return mTransformer; |
| 55 | } |
| 56 | |
| 57 | String getPrefix() { |
| 58 | return mPrefix; |
| 59 | } |
| 60 | |
| 61 | void setPrefix(String prefix) { |
| 62 | mPrefix = prefix; |
| 63 | } |
| 64 | } |
| 65 | |
| 66 | /** |
| 67 | * a given instance of this list is treated as immutable to simplify sync; |
| 68 | * we pay copying overhead whenever the list is changed rather than every time |
| 69 | * the list is referenced. |
| 70 | * The array is kept in the order the transformers are added via addTransformer |
| 71 | * (first added is 0, last added is length-1) |
| 72 | * Use an array, not a List or other Collection. This keeps the set of classes |
| 73 | * used by this code to a minimum. We want as few dependencies as possible in this |
| 74 | * code, since it is used inside the class definition system. Any class referenced here |
| 75 | * cannot be transformed by Java code. |
| 76 | */ |
| 77 | private TransformerInfo[] mTransformerList; |
| 78 | |
| 79 | /*** |
| 80 | * Is this TransformerManager for transformers capable of retransformation? |
| 81 | */ |
| 82 | private boolean mIsRetransformable; |
| 83 | |
| 84 | TransformerManager(boolean isRetransformable) { |
| 85 | mTransformerList = new TransformerInfo[0]; |
| 86 | mIsRetransformable = isRetransformable; |
| 87 | } |
| 88 | |
| 89 | boolean isRetransformable() { |
| 90 | return mIsRetransformable; |
| 91 | } |
| 92 | |
| 93 | public synchronized void |
| 94 | addTransformer( ClassFileTransformer transformer) { |
| 95 | TransformerInfo[] oldList = mTransformerList; |
| 96 | TransformerInfo[] newList = new TransformerInfo[oldList.length + 1]; |
| 97 | System.arraycopy( oldList, |
| 98 | 0, |
| 99 | newList, |
| 100 | 0, |
| 101 | oldList.length); |
| 102 | newList[oldList.length] = new TransformerInfo(transformer); |
| 103 | mTransformerList = newList; |
| 104 | } |
| 105 | |
| 106 | public synchronized boolean |
| 107 | removeTransformer(ClassFileTransformer transformer) { |
| 108 | boolean found = false; |
| 109 | TransformerInfo[] oldList = mTransformerList; |
| 110 | int oldLength = oldList.length; |
| 111 | int newLength = oldLength - 1; |
| 112 | |
| 113 | // look for it in the list, starting at the last added, and remember |
| 114 | // where it was if we found it |
| 115 | int matchingIndex = 0; |
| 116 | for ( int x = oldLength - 1; x >= 0; x-- ) { |
| 117 | if ( oldList[x].transformer() == transformer ) { |
| 118 | found = true; |
| 119 | matchingIndex = x; |
| 120 | break; |
| 121 | } |
| 122 | } |
| 123 | |
| 124 | // make a copy of the array without the matching element |
| 125 | if ( found ) { |
| 126 | TransformerInfo[] newList = new TransformerInfo[newLength]; |
| 127 | |
| 128 | // copy up to but not including the match |
| 129 | if ( matchingIndex > 0 ) { |
| 130 | System.arraycopy( oldList, |
| 131 | 0, |
| 132 | newList, |
| 133 | 0, |
| 134 | matchingIndex); |
| 135 | } |
| 136 | |
| 137 | // if there is anything after the match, copy it as well |
| 138 | if ( matchingIndex < (newLength) ) { |
| 139 | System.arraycopy( oldList, |
| 140 | matchingIndex + 1, |
| 141 | newList, |
| 142 | matchingIndex, |
| 143 | (newLength) - matchingIndex); |
| 144 | } |
| 145 | mTransformerList = newList; |
| 146 | } |
| 147 | return found; |
| 148 | } |
| 149 | |
| 150 | synchronized boolean |
| 151 | includesTransformer(ClassFileTransformer transformer) { |
| 152 | for (TransformerInfo info : mTransformerList) { |
| 153 | if ( info.transformer() == transformer ) { |
| 154 | return true; |
| 155 | } |
| 156 | } |
| 157 | return false; |
| 158 | } |
| 159 | |
| 160 | // This function doesn't actually snapshot anything, but should be |
| 161 | // used to set a local variable, which will snapshot the transformer |
| 162 | // list because of the copying semantics of mTransformerList (see |
| 163 | // the comment for mTransformerList). |
| 164 | private TransformerInfo[] |
| 165 | getSnapshotTransformerList() { |
| 166 | return mTransformerList; |
| 167 | } |
| 168 | |
| 169 | public byte[] |
| 170 | transform( ClassLoader loader, |
| 171 | String classname, |
| 172 | Class classBeingRedefined, |
| 173 | ProtectionDomain protectionDomain, |
| 174 | byte[] classfileBuffer) { |
| 175 | boolean someoneTouchedTheBytecode = false; |
| 176 | |
| 177 | TransformerInfo[] transformerList = getSnapshotTransformerList(); |
| 178 | |
| 179 | byte[] bufferToUse = classfileBuffer; |
| 180 | |
| 181 | // order matters, gotta run 'em in the order they were added |
| 182 | for ( int x = 0; x < transformerList.length; x++ ) { |
| 183 | TransformerInfo transformerInfo = transformerList[x]; |
| 184 | ClassFileTransformer transformer = transformerInfo.transformer(); |
| 185 | byte[] transformedBytes = null; |
| 186 | |
| 187 | try { |
| 188 | transformedBytes = transformer.transform( loader, |
| 189 | classname, |
| 190 | classBeingRedefined, |
| 191 | protectionDomain, |
| 192 | bufferToUse); |
| 193 | } |
| 194 | catch (Throwable t) { |
| 195 | // don't let any one transformer mess it up for the others. |
| 196 | // This is where we need to put some logging. What should go here? FIXME |
| 197 | } |
| 198 | |
| 199 | if ( transformedBytes != null ) { |
| 200 | someoneTouchedTheBytecode = true; |
| 201 | bufferToUse = transformedBytes; |
| 202 | } |
| 203 | } |
| 204 | |
| 205 | // if someone modified it, return the modified buffer. |
| 206 | // otherwise return null to mean "no transforms occurred" |
| 207 | byte [] result; |
| 208 | if ( someoneTouchedTheBytecode ) { |
| 209 | result = bufferToUse; |
| 210 | } |
| 211 | else { |
| 212 | result = null; |
| 213 | } |
| 214 | |
| 215 | return result; |
| 216 | } |
| 217 | |
| 218 | |
| 219 | int |
| 220 | getTransformerCount() { |
| 221 | TransformerInfo[] transformerList = getSnapshotTransformerList(); |
| 222 | return transformerList.length; |
| 223 | } |
| 224 | |
| 225 | boolean |
| 226 | setNativeMethodPrefix(ClassFileTransformer transformer, String prefix) { |
| 227 | TransformerInfo[] transformerList = getSnapshotTransformerList(); |
| 228 | |
| 229 | for ( int x = 0; x < transformerList.length; x++ ) { |
| 230 | TransformerInfo transformerInfo = transformerList[x]; |
| 231 | ClassFileTransformer aTransformer = transformerInfo.transformer(); |
| 232 | |
| 233 | if ( aTransformer == transformer ) { |
| 234 | transformerInfo.setPrefix(prefix); |
| 235 | return true; |
| 236 | } |
| 237 | } |
| 238 | return false; |
| 239 | } |
| 240 | |
| 241 | |
| 242 | String[] |
| 243 | getNativeMethodPrefixes() { |
| 244 | TransformerInfo[] transformerList = getSnapshotTransformerList(); |
| 245 | String[] prefixes = new String[transformerList.length]; |
| 246 | |
| 247 | for ( int x = 0; x < transformerList.length; x++ ) { |
| 248 | TransformerInfo transformerInfo = transformerList[x]; |
| 249 | prefixes[x] = transformerInfo.getPrefix(); |
| 250 | } |
| 251 | return prefixes; |
| 252 | } |
| 253 | } |