1 /*
2 * Copyright (c) 2020, 2025, 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
26 package jdk.internal.misc;
27
28 import java.io.BufferedReader;
29 import java.io.File;
30 import java.io.InputStreamReader;
31 import java.io.InputStream;
32 import java.io.IOException;
33 import java.io.PrintStream;
34 import java.net.URL;
35 import java.net.URLClassLoader;
36 import java.nio.file.InvalidPathException;
37 import java.nio.file.Path;
38 import java.util.Arrays;
39 import java.util.ArrayList;
40 import java.util.List;
41 import java.util.Map;
42 import java.util.Objects;
43 import java.util.stream.Stream;
44
45 import jdk.internal.access.SharedSecrets;
46 import jdk.internal.util.StaticProperty;
47
48 public class CDS {
49 // Must be in sync with cdsConfig.hpp
50 private static final int IS_DUMPING_ARCHIVE = 1 << 0;
51 private static final int IS_DUMPING_METHOD_HANDLES = 1 << 1;
52 private static final int IS_DUMPING_STATIC_ARCHIVE = 1 << 2;
53 private static final int IS_LOGGING_LAMBDA_FORM_INVOKERS = 1 << 3;
54 private static final int IS_USING_ARCHIVE = 1 << 4;
55 private static final int configStatus = getCDSConfigStatus();
56
57 /**
58 * Should we log the use of lambda form invokers?
59 */
60 public static boolean isLoggingLambdaFormInvokers() {
61 return (configStatus & IS_LOGGING_LAMBDA_FORM_INVOKERS) != 0;
62 }
63
64 /**
65 * Is the VM writing to a (static or dynamic) CDS archive.
66 */
67 public static boolean isDumpingArchive() {
68 return (configStatus & IS_DUMPING_ARCHIVE) != 0;
69 }
70
71 /**
72 * Is the VM using at least one CDS archive?
73 */
74 public static boolean isUsingArchive() {
75 return (configStatus & IS_USING_ARCHIVE) != 0;
76 }
77
78 /**
79 * Is dumping static archive.
80 */
81 public static boolean isDumpingStaticArchive() {
82 return (configStatus & IS_DUMPING_STATIC_ARCHIVE) != 0;
83 }
84
85 private static native int getCDSConfigStatus();
86 private static native void logLambdaFormInvoker(String line);
87
88 /**
89 * Initialize archived static fields in the given Class using archived
90 * values from CDS dump time. Also initialize the classes of objects in
91 * the archived graph referenced by those fields.
92 *
93 * Those static fields remain as uninitialized if there is no mapped CDS
94 * java heap data or there is any error during initialization of the
95 * object class in the archived graph.
96 */
97 public static native void initializeFromArchive(Class<?> c);
98
99 /**
100 * Ensure that the native representation of all archived java.lang.Module objects
101 * are properly restored.
102 */
103 public static native void defineArchivedModules(ClassLoader platformLoader, ClassLoader systemLoader);
104
105 /**
106 * Returns a predictable "random" seed derived from the VM's build ID and version,
107 * to be used by java.util.ImmutableCollections to ensure that archived
108 * ImmutableCollections are always sorted the same order for the same VM build.
109 */
110 public static native long getRandomSeedForDumping();
111
112 /**
113 * log lambda form invoker holder, name and method type
114 */
115 public static void logLambdaFormInvoker(String prefix, String holder, String name, String type) {
116 if (isLoggingLambdaFormInvokers()) {
117 logLambdaFormInvoker(prefix + " " + holder + " " + name + " " + type);
118 }
119 }
120
121 /**
122 * log species
123 */
124 public static void logSpeciesType(String prefix, String cn) {
125 if (isLoggingLambdaFormInvokers()) {
126 logLambdaFormInvoker(prefix + " " + cn);
127 }
128 }
129
130 static final String DIRECT_HOLDER_CLASS_NAME = "java.lang.invoke.DirectMethodHandle$Holder";
131 static final String DELEGATING_HOLDER_CLASS_NAME = "java.lang.invoke.DelegatingMethodHandle$Holder";
132 static final String BASIC_FORMS_HOLDER_CLASS_NAME = "java.lang.invoke.LambdaForm$Holder";
133 static final String INVOKERS_HOLDER_CLASS_NAME = "java.lang.invoke.Invokers$Holder";
134
135 private static boolean isValidHolderName(String name) {
136 return name.equals(DIRECT_HOLDER_CLASS_NAME) ||
137 name.equals(DELEGATING_HOLDER_CLASS_NAME) ||
138 name.equals(BASIC_FORMS_HOLDER_CLASS_NAME) ||
139 name.equals(INVOKERS_HOLDER_CLASS_NAME);
140 }
141
142 private static boolean isBasicTypeChar(char c) {
143 return "LIJFDV".indexOf(c) >= 0;
144 }
145
146 private static boolean isValidMethodType(String type) {
147 String[] typeParts = type.split("_");
148 // check return type (second part)
149 if (typeParts.length != 2 || typeParts[1].length() != 1
150 || !isBasicTypeChar(typeParts[1].charAt(0))) {
151 return false;
152 }
153 // first part
154 if (!isBasicTypeChar(typeParts[0].charAt(0))) {
155 return false;
156 }
157 for (int i = 1; i < typeParts[0].length(); i++) {
158 char c = typeParts[0].charAt(i);
159 if (!isBasicTypeChar(c)) {
160 if (!(c >= '0' && c <= '9')) {
161 return false;
162 }
163 }
164 }
165 return true;
166 }
167
168 // Throw exception on invalid input
169 private static void validateInputLines(String[] lines) {
170 for (String s: lines) {
171 if (!s.startsWith("[LF_RESOLVE]") && !s.startsWith("[SPECIES_RESOLVE]")) {
172 throw new IllegalArgumentException("Wrong prefix: " + s);
173 }
174
175 String[] parts = s.split(" ");
176 boolean isLF = s.startsWith("[LF_RESOLVE]");
177
178 if (isLF) {
179 if (parts.length != 4) {
180 throw new IllegalArgumentException("Incorrect number of items in the line: " + parts.length);
181 }
182 if (!isValidHolderName(parts[1])) {
183 throw new IllegalArgumentException("Invalid holder class name: " + parts[1]);
184 }
185 if (!isValidMethodType(parts[3])) {
186 throw new IllegalArgumentException("Invalid method type: " + parts[3]);
187 }
188 } else {
189 if (parts.length != 2) {
190 throw new IllegalArgumentException("Incorrect number of items in the line: " + parts.length);
191 }
192 }
193 }
194 }
195
196 /**
197 * called from vm to generate MethodHandle holder classes
198 * @return {@code Object[]} if holder classes can be generated.
199 * @param lines in format of LF_RESOLVE or SPECIES_RESOLVE output
200 */
201 private static Object[] generateLambdaFormHolderClasses(String[] lines) {
202 Objects.requireNonNull(lines);
203 validateInputLines(lines);
204 Stream<String> lineStream = Arrays.stream(lines);
205 Map<String, byte[]> result = SharedSecrets.getJavaLangInvokeAccess().generateHolderClasses(lineStream);
206 int size = result.size();
207 Object[] retArray = new Object[size * 2];
208 int index = 0;
209 for (Map.Entry<String, byte[]> entry : result.entrySet()) {
210 retArray[index++] = entry.getKey();
211 retArray[index++] = entry.getValue();
212 };
213 return retArray;
214 }
215
216 private static native void dumpClassList(String listFileName);
217 private static native void dumpDynamicArchive(String archiveFileName);
218
219 private static String drainOutput(InputStream stream, long pid, String tail, List<String> cmds) {
220 String fileName = "java_pid" + pid + "_" + tail;
221 new Thread( ()-> {
222 try (InputStreamReader isr = new InputStreamReader(stream);
223 BufferedReader rdr = new BufferedReader(isr);
224 PrintStream prt = new PrintStream(fileName)) {
225 prt.println("Command:");
226 for (String s : cmds) {
227 prt.print(s + " ");
228 }
229 prt.println("");
230 String line;
231 while((line = rdr.readLine()) != null) {
232 prt.println(line);
233 }
234 } catch (IOException e) {
235 throw new RuntimeException("IOException happens during drain stream to file " +
236 fileName + ": " + e.getMessage());
237 }}).start();
238 return fileName;
239 }
240
241 private static String[] excludeFlags = {
242 "-XX:DumpLoadedClassList=",
243 "-XX:+RecordDynamicDumpInfo",
244 "-Xshare:",
245 "-XX:SharedClassListFile=",
246 "-XX:SharedArchiveFile=",
247 "-XX:ArchiveClassesAtExit="};
248 private static boolean containsExcludedFlags(String testStr) {
249 for (String e : excludeFlags) {
250 if (testStr.contains(e)) {
251 return true;
252 }
253 }
254 return false;
255 }
256
257 /**
258 * called from jcmd VM.cds to dump static or dynamic shared archive
259 * @param isStatic true for dump static archive or false for dynnamic archive.
260 * @param fileName user input archive name, can be null.
261 * @return The archive name if successfully dumped.
262 */
263 private static String dumpSharedArchive(boolean isStatic, String fileName) throws Exception {
264 String cwd = new File("").getAbsolutePath(); // current dir used for printing message.
265 String currentPid = String.valueOf(ProcessHandle.current().pid());
266 String archiveFileName = fileName != null ? fileName :
267 "java_pid" + currentPid + (isStatic ? "_static.jsa" : "_dynamic.jsa");
268
269 String tempArchiveFileName = archiveFileName + ".temp";
270 File tempArchiveFile = new File(tempArchiveFileName);
271 // The operation below may cause exception if the file or its dir is protected.
272 if (!tempArchiveFile.exists()) {
273 tempArchiveFile.createNewFile();
274 }
275 tempArchiveFile.delete();
276
277 if (isStatic) {
278 String listFileName = archiveFileName + ".classlist";
279 File listFile = new File(listFileName);
280 if (listFile.exists()) {
281 listFile.delete();
282 }
283 dumpClassList(listFileName);
284 String jdkHome = StaticProperty.javaHome();
285 String classPath = System.getProperty("java.class.path");
286 List<String> cmds = new ArrayList<String>();
287 cmds.add(jdkHome + File.separator + "bin" + File.separator + "java"); // java
288 cmds.add("-cp");
289 cmds.add(classPath);
290 cmds.add("-Xlog:cds");
291 cmds.add("-Xshare:dump");
292 cmds.add("-XX:SharedClassListFile=" + listFileName);
293 cmds.add("-XX:SharedArchiveFile=" + tempArchiveFileName);
294
295 // All runtime args.
296 String[] vmArgs = VM.getRuntimeArguments();
297 if (vmArgs != null) {
298 for (String arg : vmArgs) {
299 if (arg != null && !containsExcludedFlags(arg)) {
300 cmds.add(arg);
301 }
302 }
303 }
304
305 Process proc = Runtime.getRuntime().exec(cmds.toArray(new String[0]));
306
307 // Drain stdout/stderr to files in new threads.
308 String stdOutFileName = drainOutput(proc.getInputStream(), proc.pid(), "stdout", cmds);
309 String stdErrFileName = drainOutput(proc.getErrorStream(), proc.pid(), "stderr", cmds);
310
311 proc.waitFor();
312 // done, delete classlist file.
313 listFile.delete();
314
315 // Check if archive has been successfully dumped. We won't reach here if exception happens.
316 // Throw exception if file is not created.
317 if (!tempArchiveFile.exists()) {
318 throw new RuntimeException("Archive file " + tempArchiveFileName +
319 " is not created, please check stdout file " +
320 cwd + File.separator + stdOutFileName + " or stderr file " +
321 cwd + File.separator + stdErrFileName + " for more detail");
322 }
323 } else {
324 dumpDynamicArchive(tempArchiveFileName);
325 if (!tempArchiveFile.exists()) {
326 throw new RuntimeException("Archive file " + tempArchiveFileName +
327 " is not created, please check current working directory " +
328 cwd + " for process " +
329 currentPid + " output for more detail");
330 }
331 }
332 // Override the existing archive file
333 File archiveFile = new File(archiveFileName);
334 if (archiveFile.exists()) {
335 archiveFile.delete();
336 }
337 if (!tempArchiveFile.renameTo(archiveFile)) {
338 throw new RuntimeException("Cannot rename temp file " + tempArchiveFileName + " to archive file" + archiveFileName);
339 }
340 // Everything goes well, print out the file name.
341 String archiveFilePath = new File(archiveFileName).getAbsolutePath();
342 System.out.println("The process was attached by jcmd and dumped a " + (isStatic ? "static" : "dynamic") + " archive " + archiveFilePath);
343 return archiveFilePath;
344 }
345
346 /**
347 * Detects if we need to emit explicit class initialization checks in
348 * AOT-cached MethodHandles and VarHandles before accessing static fields
349 * and methods.
350 * @see jdk.internal.misc.Unsafe::shouldBeInitialized
351 *
352 * @return false only if a call to {@code ensureClassInitialized} would have
353 * no effect during the application's production run.
354 */
355 public static boolean needsClassInitBarrier(Class<?> c) {
356 if (c == null) {
357 throw new NullPointerException();
358 }
359
360 if ((configStatus & IS_DUMPING_METHOD_HANDLES) == 0) {
361 return false;
362 } else {
363 return needsClassInitBarrier0(c);
364 }
365 }
366
367 private static native boolean needsClassInitBarrier0(Class<?> c);
368
369 /**
370 * This class is used only by native JVM code at CDS dump time for loading
371 * "unregistered classes", which are archived classes that are intended to
372 * be loaded by custom class loaders during runtime.
373 * See src/hotspot/share/cds/unregisteredClasses.cpp.
374 */
375 private static class UnregisteredClassLoader extends URLClassLoader {
376 private String currentClassName;
377 private Class<?> currentSuperClass;
378 private Class<?>[] currentInterfaces;
379
380 /**
381 * Used only by native code. Construct an UnregisteredClassLoader for loading
382 * unregistered classes from the specified file. If the file doesn't exist,
383 * the exception will be caughted by native code which will print a warning message and continue.
384 *
385 * @param fileName path of the the JAR file to load unregistered classes from.
386 */
387 private UnregisteredClassLoader(String fileName) throws InvalidPathException, IOException {
388 super(toURLArray(fileName), /*parent*/null);
389 currentClassName = null;
390 currentSuperClass = null;
391 currentInterfaces = null;
392 }
393
394 private static URL[] toURLArray(String fileName) throws InvalidPathException, IOException {
395 if (!((new File(fileName)).exists())) {
396 throw new IOException("No such file: " + fileName);
397 }
398 return new URL[] {
399 // Use an intermediate File object to construct a URI/URL without
400 // authority component as URLClassPath can't handle URLs with a UNC
401 // server name in the authority component.
402 Path.of(fileName).toRealPath().toFile().toURI().toURL()
403 };
404 }
405
406
407 /**
408 * Load the class of the given <code>/name<code> from the JAR file that was given to
409 * the constructor of the current UnregisteredClassLoader instance. This class must be
410 * a direct subclass of <code>superClass</code>. This class must be declared to implement
411 * the specified <code>interfaces</code>.
412 * <p>
413 * This method must be called in a single threaded context. It will never be recursed (thus
414 * the asserts)
415 *
416 * @param name the name of the class to be loaded.
417 * @param superClass must not be null. The named class must have a super class.
418 * @param interfaces could be null if the named class does not implement any interfaces.
419 */
420 private Class<?> load(String name, Class<?> superClass, Class<?>[] interfaces)
421 throws ClassNotFoundException
422 {
423 assert currentClassName == null;
424 assert currentSuperClass == null;
425 assert currentInterfaces == null;
426
427 try {
428 currentClassName = name;
429 currentSuperClass = superClass;
430 currentInterfaces = interfaces;
431
432 return findClass(name);
433 } finally {
434 currentClassName = null;
435 currentSuperClass = null;
436 currentInterfaces = null;
437 }
438 }
439
440 /**
441 * This method must be called from inside the <code>load()</code> method. The <code>/name<code>
442 * can be only:
443 * <ul>
444 * <li> the <code>name</code> parameter for <code>load()</code>
445 * <li> the name of the <code>superClass</code> parameter for <code>load()</code>
446 * <li> the name of one of the interfaces in <code>interfaces</code> parameter for <code>load()</code>
447 * <ul>
448 *
449 * For all other cases, a <code>ClassNotFoundException</code> will be thrown.
450 */
451 protected Class<?> findClass(final String name)
452 throws ClassNotFoundException
453 {
454 Objects.requireNonNull(currentClassName);
455 Objects.requireNonNull(currentSuperClass);
456
457 if (name.equals(currentClassName)) {
458 // Note: the following call will call back to <code>this.findClass(name)</code> to
459 // resolve the super types of the named class.
460 return super.findClass(name);
461 }
462 if (name.equals(currentSuperClass.getName())) {
463 return currentSuperClass;
464 }
465 if (currentInterfaces != null) {
466 for (Class<?> c : currentInterfaces) {
467 if (name.equals(c.getName())) {
468 return c;
469 }
470 }
471 }
472
473 throw new ClassNotFoundException(name);
474 }
475 }
476 }