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| 1 | +/* | |
| 2 | + * Copyright (c) 2000, 2006, Oracle and/or its affiliates. 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. Oracle designates this | |
| 8 | + * particular file as subject to the "Classpath" exception as provided | |
| 9 | + * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| 22 | + * or visit www.oracle.com if you need additional information or have any | |
| 23 | + * questions. | |
| 24 | + */ | |
| 25 | +package sun.security.provider.certpath; | |
| 26 | + | |
| 27 | + | |
| 28 | +import java.util.ArrayList; | |
| 29 | +import java.util.Collections; | |
| 30 | +import java.util.Iterator; | |
| 31 | +import java.util.List; | |
| 32 | + | |
| 33 | + | |
| 34 | +/** | |
| 35 | + * An AdjacencyList is used to store the history of certification paths | |
| 36 | + * attempted in constructing a path from an initiator to a target. The | |
| 37 | + * AdjacencyList is initialized with a <code>List</code> of | |
| 38 | + * <code>List</code>s, where each sub-<code>List</code> contains objects of | |
| 39 | + * type <code>Vertex</code>. A <code>Vertex</code> describes one possible or | |
| 40 | + * actual step in the chain building process, and the associated | |
| 41 | + * <code>Certificate</code>. Specifically, a <code>Vertex</code> object | |
| 42 | + * contains a <code>Certificate</code> and an index value referencing the | |
| 43 | + * next sub-list in the process. If the index value is -1 then this | |
| 44 | + * <code>Vertex</code> doesn't continue the attempted build path. | |
| 45 | + * <p> | |
| 46 | + * Example: | |
| 47 | + * <p> | |
| 48 | + * Attempted Paths:<ul> | |
| 49 | + * <li>C1->C2->C3 | |
| 50 | + * <li>C1->C4->C5 | |
| 51 | + * <li>C1->C4->C6 | |
| 52 | + * <li>C1->C4->C7 | |
| 53 | + * <li>C1->C8->C9 | |
| 54 | + * <li>C1->C10->C11 | |
| 55 | + * </ul> | |
| 56 | + * <p> | |
| 57 | + * AdjacencyList structure:<ul> | |
| 58 | + * <li>AL[0] = C1,1 | |
| 59 | + * <li>AL[1] = C2,2 =>C4,3 =>C8,4 =>C10,5 | |
| 60 | + * <li>AL[2] = C3,-1 | |
| 61 | + * <li>AL[3] = C5,-1 =>C6,-1 =>C7,-1 | |
| 62 | + * <li>AL[4] = C9,-1 | |
| 63 | + * <li>AL[5] = C11,-1 | |
| 64 | + * </ul> | |
| 65 | + * <p> | |
| 66 | + * The iterator method returns objects of type <code>BuildStep</code>, not | |
| 67 | + * objects of type <code>Vertex</code>. | |
| 68 | + * A <code>BuildStep</code> contains a <code>Vertex</code> and a result code, | |
| 69 | + * accessable via getResult method. There are five result values. | |
| 70 | + * <code>POSSIBLE</code> denotes that the current step represents a | |
| 71 | + * <code>Certificate</code> that the builder is considering at this point in | |
| 72 | + * the build. <code>FOLLOW</code> denotes a <code>Certificate</code> (one of | |
| 73 | + * those noted as <code>POSSIBLE</code>) that the builder is using to try | |
| 74 | + * extending the chain. <code>BACK</code> represents that a | |
| 75 | + * <code>FOLLOW</code> was incorrect, and is being removed from the chain. | |
| 76 | + * There is exactly one <code>FOLLOW</code> for each <code>BACK</code>. The | |
| 77 | + * values <code>SUCCEED</code> and <code>FAIL</code> mean that we've come to | |
| 78 | + * the end of the build process, and there will not be any more entries in | |
| 79 | + * the list. | |
| 80 | + * <p> | |
| 81 | + * @see sun.security.provider.certpath.BuildStep | |
| 82 | + * @see sun.security.provider.certpath.Vertex | |
| 83 | + * <p> | |
| 84 | + * @author seth proctor | |
| 85 | + * @since 1.4 | |
| 86 | + */ | |
| 87 | +public class AdjacencyList { | |
| 88 | + | |
| 89 | + // the actual set of steps the AdjacencyList represents | |
| 90 | + private ArrayList<BuildStep> mStepList; | |
| 91 | + | |
| 92 | + // the original list, just for the toString method | |
| 93 | + private List<List<Vertex>> mOrigList; | |
| 94 | + | |
| 95 | + /** | |
| 96 | + * Constructs a new <code>AdjacencyList</code> based on the specified | |
| 97 | + * <code>List</code>. See the example above. | |
| 98 | + * | |
| 99 | + * @param list a <code>List</code> of <code>List</code>s of | |
| 100 | + * <code>Vertex</code> objects | |
| 101 | + */ | |
| 102 | + public AdjacencyList(List<List<Vertex>> list) { | |
| 103 | + mStepList = new ArrayList<BuildStep>(); | |
| 104 | + mOrigList = list; | |
| 105 | + buildList(list, 0, null); | |
| 106 | + } | |
| 107 | + | |
| 108 | + /** | |
| 109 | + * Gets an <code>Iterator</code> to iterate over the set of | |
| 110 | + * <code>BuildStep</code>s in build-order. Any attempts to change | |
| 111 | + * the list through the remove method will fail. | |
| 112 | + * | |
| 113 | + * @return an <code>Iterator</code> over the <code>BuildStep</code>s | |
| 114 | + */ | |
| 115 | + public Iterator<BuildStep> iterator() { | |
| 116 | + return Collections.unmodifiableList(mStepList).iterator(); | |
| 117 | + } | |
| 118 | + | |
| 119 | + /** | |
| 120 | + * Recursive, private method which actually builds the step list from | |
| 121 | + * the given adjacency list. <code>Follow</code> is the parent BuildStep | |
| 122 | + * that we followed to get here, and if it's null, it means that we're | |
| 123 | + * at the start. | |
| 124 | + */ | |
| 125 | + private boolean buildList(List<List<Vertex>> theList, int index, | |
| 126 | + BuildStep follow) { | |
| 127 | + | |
| 128 | + // Each time this method is called, we're examining a new list | |
| 129 | + // from the global list. So, we have to start by getting the list | |
| 130 | + // that contains the set of Vertexes we're considering. | |
| 131 | + List<Vertex> l = theList.get(index); | |
| 132 | + | |
| 133 | + try { | |
| 134 | + // we're interested in the case where all indexes are -1... | |
| 135 | + boolean allNegOne = true; | |
| 136 | + // ...and in the case where every entry has a Throwable | |
| 137 | + boolean allXcps = true; | |
| 138 | + | |
| 139 | + for (Vertex v : l) { | |
| 140 | + if (v.getIndex() != -1) { | |
| 141 | + // count an empty list the same as an index of -1...this | |
| 142 | + // is to patch a bug somewhere in the builder | |
| 143 | + if (theList.get(v.getIndex()).size() != 0) | |
| 144 | + allNegOne = false; | |
| 145 | + } | |
| 146 | + else | |
| 147 | + if (v.getThrowable() == null) | |
| 148 | + allXcps = false; | |
| 149 | + | |
| 150 | + // every entry, regardless of the final use for it, is always | |
| 151 | + // entered as a possible step before we take any actions | |
| 152 | + mStepList.add(new BuildStep(v, BuildStep.POSSIBLE)); | |
| 153 | + } | |
| 154 | + | |
| 155 | + if (allNegOne) { | |
| 156 | + // There are two cases that we could be looking at here. We | |
| 157 | + // may need to back up, or the build may have succeeded at | |
| 158 | + // this point. This is based on whether or not any | |
| 159 | + // exceptions were found in the list. | |
| 160 | + if (allXcps) { | |
| 161 | + // we need to go back...see if this is the last one | |
| 162 | + if (follow == null) | |
| 163 | + mStepList.add(new BuildStep(null, BuildStep.FAIL)); | |
| 164 | + else | |
| 165 | + mStepList.add(new BuildStep(follow.getVertex(), | |
| 166 | + BuildStep.BACK)); | |
| 167 | + | |
| 168 | + return false; | |
| 169 | + } else { | |
| 170 | + // we succeeded...now the only question is which is the | |
| 171 | + // successful step? If there's only one entry without | |
| 172 | + // a throwable, then that's the successful step. Otherwise, | |
| 173 | + // we'll have to make some guesses... | |
| 174 | + List<Vertex> possibles = new ArrayList<Vertex>(); | |
| 175 | + for (Vertex v : l) { | |
| 176 | + if (v.getThrowable() == null) | |
| 177 | + possibles.add(v); | |
| 178 | + } | |
| 179 | + | |
| 180 | + if (possibles.size() == 1) { | |
| 181 | + // real easy...we've found the final Vertex | |
| 182 | + mStepList.add(new BuildStep(possibles.get(0), | |
| 183 | + BuildStep.SUCCEED)); | |
| 184 | + } else { | |
| 185 | + // ok...at this point, there is more than one Cert | |
| 186 | + // which might be the succeed step...how do we know | |
| 187 | + // which it is? I'm going to assume that our builder | |
| 188 | + // algorithm is good enough to know which is the | |
| 189 | + // correct one, and put it first...but a FIXME goes | |
| 190 | + // here anyway, and we should be comparing to the | |
| 191 | + // target/initiator Cert... | |
| 192 | + mStepList.add(new BuildStep(possibles.get(0), | |
| 193 | + BuildStep.SUCCEED)); | |
| 194 | + } | |
| 195 | + | |
| 196 | + return true; | |
| 197 | + } | |
| 198 | + } else { | |
| 199 | + // There's at least one thing that we can try before we give | |
| 200 | + // up and go back. Run through the list now, and enter a new | |
| 201 | + // BuildStep for each path that we try to follow. If none of | |
| 202 | + // the paths we try produce a successful end, we're going to | |
| 203 | + // have to back out ourselves. | |
| 204 | + boolean success = false; | |
| 205 | + | |
| 206 | + for (Vertex v : l) { | |
| 207 | + | |
| 208 | + // Note that we'll only find a SUCCEED case when we're | |
| 209 | + // looking at the last possible path, so we don't need to | |
| 210 | + // consider success in the while loop | |
| 211 | + | |
| 212 | + if (v.getIndex() != -1) { | |
| 213 | + if (theList.get(v.getIndex()).size() != 0) { | |
| 214 | + // If the entry we're looking at doesn't have an | |
| 215 | + // index of -1, and doesn't lead to an empty list, | |
| 216 | + // then it's something we follow! | |
| 217 | + BuildStep bs = new BuildStep(v, BuildStep.FOLLOW); | |
| 218 | + mStepList.add(bs); | |
| 219 | + success = buildList(theList, v.getIndex(), bs); | |
| 220 | + } | |
| 221 | + } | |
| 222 | + } | |
| 223 | + | |
| 224 | + if (success) { | |
| 225 | + // We're already finished! | |
| 226 | + return true; | |
| 227 | + } else { | |
| 228 | + // We failed, and we've exhausted all the paths that we | |
| 229 | + // could take. The only choice is to back ourselves out. | |
| 230 | + if (follow == null) | |
| 231 | + mStepList.add(new BuildStep(null, BuildStep.FAIL)); | |
| 232 | + else | |
| 233 | + mStepList.add(new BuildStep(follow.getVertex(), | |
| 234 | + BuildStep.BACK)); | |
| 235 | + | |
| 236 | + return false; | |
| 237 | + } | |
| 238 | + } | |
| 239 | + } | |
| 240 | + catch (Exception e) {} | |
| 241 | + | |
| 242 | + // we'll never get here, but you know java... | |
| 243 | + return false; | |
| 244 | + } | |
| 245 | + | |
| 246 | + /** | |
| 247 | + * Prints out a string representation of this AdjacencyList. | |
| 248 | + * | |
| 249 | + * @return String representation | |
| 250 | + */ | |
| 251 | + public String toString() { | |
| 252 | + String out = "[\n"; | |
| 253 | + | |
| 254 | + int i = 0; | |
| 255 | + for (List<Vertex> l : mOrigList) { | |
| 256 | + out = out + "LinkedList[" + i++ + "]:\n"; | |
| 257 | + | |
| 258 | + for (Vertex step : l) { | |
| 259 | + try { | |
| 260 | + out = out + step.toString(); | |
| 261 | + out = out + "\n"; | |
| 262 | + } | |
| 263 | + catch (Exception e) { out = out + "No Such Element\n"; } | |
| 264 | + } | |
| 265 | + } | |
| 266 | + out = out + "]\n"; | |
| 267 | + | |
| 268 | + return out; | |
| 269 | + } | |
| 270 | +} | |