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 IS_DUMPING_HEAP = 1 << 5;
56 private static final int IS_LOGGING_DYNAMIC_PROXIES = 1 << 6;
57 private static final int IS_DUMPING_PACKAGES = 1 << 7;
58 private static final int IS_DUMPING_PROTECTION_DOMAINS = 1 << 8;
59 private static final int configStatus = getCDSConfigStatus();
60
61 /**
62 * Should we log the use of lambda form invokers?
63 */
64 public static boolean isLoggingLambdaFormInvokers() {
65 return (configStatus & IS_LOGGING_LAMBDA_FORM_INVOKERS) != 0;
66 }
67
68 /**
69 * Is the VM writing to a (static or dynamic) CDS archive.
70 */
71 public static boolean isDumpingArchive() {
72 return (configStatus & IS_DUMPING_ARCHIVE) != 0;
73 }
74
75 /**
76 * Is the VM using at least one CDS archive?
77 */
78 public static boolean isUsingArchive() {
79 return (configStatus & IS_USING_ARCHIVE) != 0;
80 }
81
82 /**
83 * Is dumping static archive.
84 */
85 public static boolean isDumpingStaticArchive() {
86 return (configStatus & IS_DUMPING_STATIC_ARCHIVE) != 0;
87 }
88
89 public static boolean isDumpingHeap() {
90 return (configStatus & IS_DUMPING_HEAP) != 0;
91 }
92
93 public static boolean isLoggingDynamicProxies() {
94 return (configStatus & IS_LOGGING_DYNAMIC_PROXIES) != 0;
95 }
96
97 public static boolean isDumpingPackages() {
98 return (configStatus & IS_DUMPING_PACKAGES) != 0;
99 }
100
101 public static boolean isDumpingProtectionDomains() {
102 return (configStatus & IS_DUMPING_PROTECTION_DOMAINS) != 0;
103 }
104
105 public static boolean isSingleThreadVM() {
106 return isDumpingStaticArchive();
107 }
108
109 private static native int getCDSConfigStatus();
110 private static native void logLambdaFormInvoker(String line);
111
112
113 // Used only when dumping static archive to keep weak references alive to
114 // ensure that Soft/Weak Reference objects can be reliably archived.
115 private static ArrayList<Object> keepAliveList;
116
117 public static void keepAlive(Object s) {
118 assert isSingleThreadVM(); // no need for synchronization
119 assert isDumpingStaticArchive();
120 if (keepAliveList == null) {
121 keepAliveList = new ArrayList<>();
122 }
123 keepAliveList.add(s);
124 }
125
126 // This is called by native JVM code at the very end of Java execution before
127 // dumping the static archive.
128 // It collects the objects from keepAliveList so that they can be easily processed
129 // by the native JVM code to check that any Reference objects that need special
130 // clean up must have been registed with keepAlive()
131 private static Object[] getKeepAliveObjects() {
132 return keepAliveList.toArray();
133 }
134
135 /**
136 * Initialize archived static fields in the given Class using archived
137 * values from CDS dump time. Also initialize the classes of objects in
138 * the archived graph referenced by those fields.
139 *
140 * Those static fields remain as uninitialized if there is no mapped CDS
141 * java heap data or there is any error during initialization of the
142 * object class in the archived graph.
143 */
144 public static native void initializeFromArchive(Class<?> c);
145
146 /**
147 * Ensure that the native representation of all archived java.lang.Module objects
148 * are properly restored.
149 */
150 public static native void defineArchivedModules(ClassLoader platformLoader, ClassLoader systemLoader);
151
152 /**
153 * Returns a predictable "random" seed derived from the VM's build ID and version,
154 * to be used by java.util.ImmutableCollections to ensure that archived
155 * ImmutableCollections are always sorted the same order for the same VM build.
156 */
157 public static native long getRandomSeedForDumping();
158
159 /**
160 * log lambda form invoker holder, name and method type
161 */
162 public static void logLambdaFormInvoker(String prefix, String holder, String name, String type) {
163 if (isLoggingLambdaFormInvokers()) {
164 logLambdaFormInvoker(prefix + " " + holder + " " + name + " " + type);
165 }
166 }
167
168 /**
169 * log species
170 */
171 public static void logSpeciesType(String prefix, String cn) {
172 if (isLoggingLambdaFormInvokers()) {
173 logLambdaFormInvoker(prefix + " " + cn);
174 }
175 }
176
177 public static void logDynamicProxy(ClassLoader loader, String proxyName,
178 Class<?>[] interfaces, int accessFlags) {
179 Objects.requireNonNull(proxyName);
180 Objects.requireNonNull(interfaces);
181 logDynamicProxy0(loader, proxyName, interfaces, accessFlags);
182 }
183 private static native void logDynamicProxy0(ClassLoader loader, String proxyName,
184 Class<?>[] interfaces, int accessFlags);
185
186 static final String DIRECT_HOLDER_CLASS_NAME = "java.lang.invoke.DirectMethodHandle$Holder";
187 static final String DELEGATING_HOLDER_CLASS_NAME = "java.lang.invoke.DelegatingMethodHandle$Holder";
188 static final String BASIC_FORMS_HOLDER_CLASS_NAME = "java.lang.invoke.LambdaForm$Holder";
189 static final String INVOKERS_HOLDER_CLASS_NAME = "java.lang.invoke.Invokers$Holder";
190
191 private static boolean isValidHolderName(String name) {
192 return name.equals(DIRECT_HOLDER_CLASS_NAME) ||
193 name.equals(DELEGATING_HOLDER_CLASS_NAME) ||
194 name.equals(BASIC_FORMS_HOLDER_CLASS_NAME) ||
195 name.equals(INVOKERS_HOLDER_CLASS_NAME);
196 }
197
198 private static boolean isBasicTypeChar(char c) {
199 return "LIJFDV".indexOf(c) >= 0;
200 }
201
202 private static boolean isValidMethodType(String type) {
203 String[] typeParts = type.split("_");
204 // check return type (second part)
205 if (typeParts.length != 2 || typeParts[1].length() != 1
206 || !isBasicTypeChar(typeParts[1].charAt(0))) {
207 return false;
208 }
209 // first part
210 if (!isBasicTypeChar(typeParts[0].charAt(0))) {
211 return false;
212 }
213 for (int i = 1; i < typeParts[0].length(); i++) {
214 char c = typeParts[0].charAt(i);
215 if (!isBasicTypeChar(c)) {
216 if (!(c >= '0' && c <= '9')) {
217 return false;
218 }
219 }
220 }
221 return true;
222 }
223
224 // Throw exception on invalid input
225 private static void validateInputLines(String[] lines) {
226 for (String s: lines) {
227 if (!s.startsWith("[LF_RESOLVE]") && !s.startsWith("[SPECIES_RESOLVE]")) {
228 throw new IllegalArgumentException("Wrong prefix: " + s);
229 }
230
231 String[] parts = s.split(" ");
232 boolean isLF = s.startsWith("[LF_RESOLVE]");
233
234 if (isLF) {
235 if (parts.length != 4) {
236 throw new IllegalArgumentException("Incorrect number of items in the line: " + parts.length);
237 }
238 if (!isValidHolderName(parts[1])) {
239 throw new IllegalArgumentException("Invalid holder class name: " + parts[1]);
240 }
241 if (!isValidMethodType(parts[3])) {
242 throw new IllegalArgumentException("Invalid method type: " + parts[3]);
243 }
244 } else {
245 if (parts.length != 2) {
246 throw new IllegalArgumentException("Incorrect number of items in the line: " + parts.length);
247 }
248 }
249 }
250 }
251
252 /**
253 * called from vm to generate MethodHandle holder classes
254 * @return {@code Object[]} if holder classes can be generated.
255 * @param lines in format of LF_RESOLVE or SPECIES_RESOLVE output
256 */
257 private static Object[] generateLambdaFormHolderClasses(String[] lines) {
258 Objects.requireNonNull(lines);
259 validateInputLines(lines);
260 Stream<String> lineStream = Arrays.stream(lines);
261 Map<String, byte[]> result = SharedSecrets.getJavaLangInvokeAccess().generateHolderClasses(lineStream);
262 int size = result.size();
263 Object[] retArray = new Object[size * 2];
264 int index = 0;
265 for (Map.Entry<String, byte[]> entry : result.entrySet()) {
266 retArray[index++] = entry.getKey();
267 retArray[index++] = entry.getValue();
268 };
269 return retArray;
270 }
271
272 private static native void dumpClassList(String listFileName);
273 private static native void dumpDynamicArchive(String archiveFileName);
274
275 private static String drainOutput(InputStream stream, long pid, String tail, List<String> cmds) {
276 String fileName = "java_pid" + pid + "_" + tail;
277 new Thread( ()-> {
278 try (InputStreamReader isr = new InputStreamReader(stream);
279 BufferedReader rdr = new BufferedReader(isr);
280 PrintStream prt = new PrintStream(fileName)) {
281 prt.println("Command:");
282 for (String s : cmds) {
283 prt.print(s + " ");
284 }
285 prt.println("");
286 String line;
287 while((line = rdr.readLine()) != null) {
288 prt.println(line);
289 }
290 } catch (IOException e) {
291 throw new RuntimeException("IOException happens during drain stream to file " +
292 fileName + ": " + e.getMessage());
293 }}).start();
294 return fileName;
295 }
296
297 private static String[] excludeFlags = {
298 "-XX:DumpLoadedClassList=",
299 "-XX:+RecordDynamicDumpInfo",
300 "-Xshare:",
301 "-XX:SharedClassListFile=",
302 "-XX:SharedArchiveFile=",
303 "-XX:ArchiveClassesAtExit="};
304 private static boolean containsExcludedFlags(String testStr) {
305 for (String e : excludeFlags) {
306 if (testStr.contains(e)) {
307 return true;
308 }
309 }
310 return false;
311 }
312
313 /**
314 * called from jcmd VM.cds to dump static or dynamic shared archive
315 * @param isStatic true for dump static archive or false for dynnamic archive.
316 * @param fileName user input archive name, can be null.
317 * @return The archive name if successfully dumped.
318 */
319 private static String dumpSharedArchive(boolean isStatic, String fileName) throws Exception {
320 String cwd = new File("").getAbsolutePath(); // current dir used for printing message.
321 String currentPid = String.valueOf(ProcessHandle.current().pid());
322 String archiveFileName = fileName != null ? fileName :
323 "java_pid" + currentPid + (isStatic ? "_static.jsa" : "_dynamic.jsa");
324
325 String tempArchiveFileName = archiveFileName + ".temp";
326 File tempArchiveFile = new File(tempArchiveFileName);
327 // The operation below may cause exception if the file or its dir is protected.
328 if (!tempArchiveFile.exists()) {
329 tempArchiveFile.createNewFile();
330 }
331 tempArchiveFile.delete();
332
333 if (isStatic) {
334 String listFileName = archiveFileName + ".classlist";
335 File listFile = new File(listFileName);
336 if (listFile.exists()) {
337 listFile.delete();
338 }
339 dumpClassList(listFileName);
340 String jdkHome = StaticProperty.javaHome();
341 String classPath = System.getProperty("java.class.path");
342 List<String> cmds = new ArrayList<String>();
343 cmds.add(jdkHome + File.separator + "bin" + File.separator + "java"); // java
344 cmds.add("-cp");
345 cmds.add(classPath);
346 cmds.add("-Xlog:cds");
347 cmds.add("-Xshare:dump");
348 cmds.add("-XX:SharedClassListFile=" + listFileName);
349 cmds.add("-XX:SharedArchiveFile=" + tempArchiveFileName);
350
351 // All runtime args.
352 String[] vmArgs = VM.getRuntimeArguments();
353 if (vmArgs != null) {
354 for (String arg : vmArgs) {
355 if (arg != null && !containsExcludedFlags(arg)) {
356 cmds.add(arg);
357 }
358 }
359 }
360
361 Process proc = Runtime.getRuntime().exec(cmds.toArray(new String[0]));
362
363 // Drain stdout/stderr to files in new threads.
364 String stdOutFileName = drainOutput(proc.getInputStream(), proc.pid(), "stdout", cmds);
365 String stdErrFileName = drainOutput(proc.getErrorStream(), proc.pid(), "stderr", cmds);
366
367 proc.waitFor();
368 // done, delete classlist file.
369 listFile.delete();
370
371 // Check if archive has been successfully dumped. We won't reach here if exception happens.
372 // Throw exception if file is not created.
373 if (!tempArchiveFile.exists()) {
374 throw new RuntimeException("Archive file " + tempArchiveFileName +
375 " is not created, please check stdout file " +
376 cwd + File.separator + stdOutFileName + " or stderr file " +
377 cwd + File.separator + stdErrFileName + " for more detail");
378 }
379 } else {
380 dumpDynamicArchive(tempArchiveFileName);
381 if (!tempArchiveFile.exists()) {
382 throw new RuntimeException("Archive file " + tempArchiveFileName +
383 " is not created, please check current working directory " +
384 cwd + " for process " +
385 currentPid + " output for more detail");
386 }
387 }
388 // Override the existing archive file
389 File archiveFile = new File(archiveFileName);
390 if (archiveFile.exists()) {
391 archiveFile.delete();
392 }
393 if (!tempArchiveFile.renameTo(archiveFile)) {
394 throw new RuntimeException("Cannot rename temp file " + tempArchiveFileName + " to archive file" + archiveFileName);
395 }
396 // Everything goes well, print out the file name.
397 String archiveFilePath = new File(archiveFileName).getAbsolutePath();
398 System.out.println("The process was attached by jcmd and dumped a " + (isStatic ? "static" : "dynamic") + " archive " + archiveFilePath);
399 return archiveFilePath;
400 }
401
402 /**
403 * Detects if we need to emit explicit class initialization checks in
404 * AOT-cached MethodHandles and VarHandles before accessing static fields
405 * and methods.
406 * @see jdk.internal.misc.Unsafe::shouldBeInitialized
407 *
408 * @return false only if a call to {@code ensureClassInitialized} would have
409 * no effect during the application's production run.
410 */
411 public static boolean needsClassInitBarrier(Class<?> c) {
412 if (c == null) {
413 throw new NullPointerException();
414 }
415
416 if ((configStatus & IS_DUMPING_METHOD_HANDLES) == 0) {
417 return false;
418 } else {
419 return needsClassInitBarrier0(c);
420 }
421 }
422
423 private static native boolean needsClassInitBarrier0(Class<?> c);
424
425 /**
426 * This class is used only by native JVM code at CDS dump time for loading
427 * "unregistered classes", which are archived classes that are intended to
428 * be loaded by custom class loaders during runtime.
429 * See src/hotspot/share/cds/unregisteredClasses.cpp.
430 */
431 private static class UnregisteredClassLoader extends URLClassLoader {
432 private String currentClassName;
433 private Class<?> currentSuperClass;
434 private Class<?>[] currentInterfaces;
435
436 /**
437 * Used only by native code. Construct an UnregisteredClassLoader for loading
438 * unregistered classes from the specified file. If the file doesn't exist,
439 * the exception will be caughted by native code which will print a warning message and continue.
440 *
441 * @param fileName path of the the JAR file to load unregistered classes from.
442 */
443 private UnregisteredClassLoader(String fileName) throws InvalidPathException, IOException {
444 super(toURLArray(fileName), /*parent*/null);
445 currentClassName = null;
446 currentSuperClass = null;
447 currentInterfaces = null;
448 }
449
450 private static URL[] toURLArray(String fileName) throws InvalidPathException, IOException {
451 if (!((new File(fileName)).exists())) {
452 throw new IOException("No such file: " + fileName);
453 }
454 return new URL[] {
455 // Use an intermediate File object to construct a URI/URL without
456 // authority component as URLClassPath can't handle URLs with a UNC
457 // server name in the authority component.
458 Path.of(fileName).toRealPath().toFile().toURI().toURL()
459 };
460 }
461
462
463 /**
464 * Load the class of the given <code>/name<code> from the JAR file that was given to
465 * the constructor of the current UnregisteredClassLoader instance. This class must be
466 * a direct subclass of <code>superClass</code>. This class must be declared to implement
467 * the specified <code>interfaces</code>.
468 * <p>
469 * This method must be called in a single threaded context. It will never be recursed (thus
470 * the asserts)
471 *
472 * @param name the name of the class to be loaded.
473 * @param superClass must not be null. The named class must have a super class.
474 * @param interfaces could be null if the named class does not implement any interfaces.
475 */
476 private Class<?> load(String name, Class<?> superClass, Class<?>[] interfaces)
477 throws ClassNotFoundException
478 {
479 assert currentClassName == null;
480 assert currentSuperClass == null;
481 assert currentInterfaces == null;
482
483 try {
484 currentClassName = name;
485 currentSuperClass = superClass;
486 currentInterfaces = interfaces;
487
488 return findClass(name);
489 } finally {
490 currentClassName = null;
491 currentSuperClass = null;
492 currentInterfaces = null;
493 }
494 }
495
496 /**
497 * This method must be called from inside the <code>load()</code> method. The <code>/name<code>
498 * can be only:
499 * <ul>
500 * <li> the <code>name</code> parameter for <code>load()</code>
501 * <li> the name of the <code>superClass</code> parameter for <code>load()</code>
502 * <li> the name of one of the interfaces in <code>interfaces</code> parameter for <code>load()</code>
503 * <ul>
504 *
505 * For all other cases, a <code>ClassNotFoundException</code> will be thrown.
506 */
507 protected Class<?> findClass(final String name)
508 throws ClassNotFoundException
509 {
510 Objects.requireNonNull(currentClassName);
511 Objects.requireNonNull(currentSuperClass);
512
513 if (name.equals(currentClassName)) {
514 // Note: the following call will call back to <code>this.findClass(name)</code> to
515 // resolve the super types of the named class.
516 return super.findClass(name);
517 }
518 if (name.equals(currentSuperClass.getName())) {
519 return currentSuperClass;
520 }
521 if (currentInterfaces != null) {
522 for (Class<?> c : currentInterfaces) {
523 if (name.equals(c.getName())) {
524 return c;
525 }
526 }
527 }
528
529 throw new ClassNotFoundException(name);
530 }
531 }
532
533 /**
534 * This class is used only by native JVM code to spawn a child JVM process to assemble
535 * the AOT cache. <code>args[]</code> are passed in the <code>JAVA_TOOL_OPTIONS</code>
536 * environment variable as described in
537 * https://docs.oracle.com/en/java/javase/24/docs/specs/jvmti.html#tooloptions
538 */
539 private static class ProcessLauncher {
540 static int execWithJavaToolOptions(String javaLauncher, String args[]) throws IOException, InterruptedException {
541 ProcessBuilder pb = new ProcessBuilder().inheritIO().command(javaLauncher);
542 StringBuilder sb = new StringBuilder();
543 String prefix = "";
544 for (String arg : args) {
545 sb.append(prefix);
546
547 for (int i = 0; i < arg.length(); i++) {
548 char c = arg.charAt(i);
549 if (c == '"' || Character.isWhitespace(c)) {
550 sb.append('\'');
551 sb.append(c);
552 sb.append('\'');
553 } else if (c == '\'') {
554 sb.append('"');
555 sb.append(c);
556 sb.append('"');
557 } else {
558 sb.append(c);
559 }
560 }
561
562 prefix = " ";
563 }
564
565 Map<String, String> env = pb.environment();
566 env.put("JAVA_TOOL_OPTIONS", sb.toString());
567 env.remove("_JAVA_OPTIONS");
568 env.remove("CLASSPATH");
569 Process process = pb.start();
570 return process.waitFor();
571 }
572 }
573
574 /**
575 * This class is to ensure that the dynamic CDS archive contains at least one class, so we can avoid
576 * error handling for the degenerative case where the dynamic archive is completely empty (which doesn't
577 * happen for realistic applications).
578 */
579 private static class DummyForDynamicArchive {}
580 }