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