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