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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * version 2 for more details (a copy is included in the LICENSE file that

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 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

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/*

 * @test

 * @summary Tests how CDS works when critical library classes are replaced with JVMTI ClassFileLoadHook

 * @library /test/lib

 * @requires vm.cds

 * @build sun.hotspot.WhiteBox

 * @run driver ClassFileInstaller -jar whitebox.jar sun.hotspot.WhiteBox

 * @run main/othervm/native ReplaceCriticalClasses

 */

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import jdk.test.lib.cds.CDSTestUtils;

import jdk.test.lib.cds.CDSOptions;

import jdk.test.lib.process.OutputAnalyzer;

import sun.hotspot.WhiteBox;

public class ReplaceCriticalClasses {

    public static void main(String args[]) throws Throwable {

        if (args.length == 0) {

            launchChildProcesses();

        } else if (args.length == 3 && args[0].equals("child")) {

            Class klass = Class.forName(args[2].replace("/", "."));

            if (args[1].equals("-shared")) {

                testInChild(true, klass);

            } else if (args[1].equals("-notshared")) {

                testInChild(false, klass);

            } else {

                throw new RuntimeException("Unknown child exec option " + args[1]);

            }

            return;

        } else {

            throw new RuntimeException("Usage: @run main/othervm/native ReplaceCriticalClasses");

        }

    }

    static void launchChildProcesses() throws Throwable {

        String tests[] = {

            // CDS should be disabled -- these critical classes will be replaced

            // because JvmtiExport::early_class_hook_env() is true.

            "-early -notshared java/lang/Object",

            "-early -notshared java/lang/String",

            "-early -notshared java/lang/Cloneable",

            "-early -notshared java/io/Serializable",

            // CDS should not be disabled -- these critical classes cannot be replaced because

            // JvmtiExport::early_class_hook_env() is false.

            "java/lang/Object",

            "java/lang/String",

            "java/lang/Cloneable",

            "java/io/Serializable",

            // Try to replace classes that are used by the archived subgraph graphs.

            "-subgraph java/util/ArrayList",

            "-subgraph java/lang/module/ResolvedModule",

            // Replace classes that are loaded after JVMTI_PHASE_PRIMORDIAL. It's OK to replace such

            // classes even when CDS is enabled. Nothing bad should happen.

            "-notshared jdk/internal/vm/PostVMInitHook",

            "-notshared java/util/Locale",

            "-notshared sun/util/locale/BaseLocale",

            "-notshared java/lang/Readable",

        };

        int n = 0;

        for (String s : tests) {

            System.out.println("Test case[" + (n++) + "] = \"" + s + "\"");

            String args[] = s.split("\\s+"); // split by space character

            launchChild(args);

        }

    }

    static void launchChild(String args[]) throws Throwable {

        if (args.length < 1) {

            throw new RuntimeException("Invalid test case. Should be <-early> <-subgraph> <-notshared> klassName");

        }

        String klassName = null;

        String early = "";

        boolean subgraph = false;

        String shared = "-shared";

        for (int i=0; i<args.length-1; i++) {

            String opt = args[i];

            if (opt.equals("-early")) {

                early = "-early,";

            } else if (opt.equals("-subgraph")) {

                subgraph = true;

            } else if (opt.equals("-notshared")) {

                shared = opt;

            } else {

                throw new RuntimeException("Unknown option: " + opt);

            }

        }

        klassName = args[args.length-1];

        Class.forName(klassName.replace("/", ".")); // make sure it's a valid class

        // We will pass an option like "-agentlib:SimpleClassFileLoadHook=java/util/Locale,XXX,XXX".

        // The SimpleClassFileLoadHook agent would attempt to hook the java/util/Locale class

        // but leave the class file bytes unchanged (it replaces all bytes "XXX" with "XXX", i.e.,

        // a no-op). JVMTI doesn't check the class file bytes returned by the agent, so as long

        // as the agent returns a buffer, it will not load the class from CDS, and will instead

        // load the class by parsing the buffer.

        //

        // Note that for safety we don't change the contents of the class file bytes. If in the

        // future JVMTI starts checking the contents of the class file bytes, this test would need

        // to be updated. (You'd see the test case with java/util/Locale staring to fail).

        String agent = "-agentlib:SimpleClassFileLoadHook=" + early + klassName + ",XXX,XXX";

        CDSOptions opts = (new CDSOptions())

            .setXShareMode("auto")

            .setUseSystemArchive(true)

            .setUseVersion(false)

            .addSuffix("-showversion",

                       "-Xlog:cds",

                       "-XX:+UnlockDiagnosticVMOptions",

                       agent,

                       "-XX:+WhiteBoxAPI",

                       "-Xbootclasspath/a:" + ClassFileInstaller.getJarPath("whitebox.jar"));

        if (subgraph) {

            opts.addSuffix("-Xlog:cds+heap",

                           "-Xlog:class+load");

        }

        opts.addSuffix("ReplaceCriticalClasses",

                       "child",

                       shared,

                       klassName);

        final boolean expectDisable = !early.equals("");

        final boolean checkSubgraph = subgraph;

        CDSTestUtils.run(opts).assertNormalExit(out -> {

                if (expectDisable) {

                    out.shouldContain("UseSharedSpaces: CDS is disabled because early JVMTI ClassFileLoadHook is in use.");

                    System.out.println("CDS disabled as expected");

                }

                if (checkSubgraph) {

                    // As of 2018/10/21 the classes in the archived subgraphs won't be

                    // replaced because all archived subgraphs were loaded in JVMTI_PHASE_PRIMORDIAL.

                    //

                    // This is the first class to be loaded after JVMTI has exited JVMTI_PHASE_PRIMORDIAL.

                    // Make sure no subgraphs are loaded afterwards.

                    //

                    // Can't use out.shouldNotMatch() because that doesn't match across multiple lines.

                    String firstNonPrimordialClass = "jdk.jfr.internal.EventWriter";

                    String regexp = firstNonPrimordialClass + ".*initialize_from_archived_subgraph";

                    Pattern regex = Pattern.compile(regexp, Pattern.DOTALL);

                    Matcher matcher = regex.matcher(out.getStdout());

                    if (matcher.find()) {

                        out.reportDiagnosticSummary();

                        throw new RuntimeException("'" + regexp

                                                   + "' found in stdout: '" + matcher.group() + "' \n");

                    }

                }

            });

    }

    static void testInChild(boolean shouldBeShared, Class klass) {

        WhiteBox wb = WhiteBox.getWhiteBox();

        if (shouldBeShared && !wb.isSharedClass(klass)) {

            throw new RuntimeException(klass + " should be shared but but actually is not.");

        }

        if (!shouldBeShared && wb.isSharedClass(klass)) {

            throw new RuntimeException(klass + " should not be shared but actually is.");

        }

        System.out.println("wb.isSharedClass(klass): " + wb.isSharedClass(klass) + " == " + shouldBeShared);

        String strings[] = {

            // interned strings from j.l.Object

            "@",

            "nanosecond timeout value out of range",

            "timeoutMillis value is negative",

            // interned strings from j.l.Integer

            "0",

            "0X",

            "0x",

            "int"

        };

        // Make sure the interned string table is same

        for (String s : strings) {

            String i = s.intern();

            if (s != i) {

                throw new RuntimeException("Interned string mismatch: \"" + s + "\" @ " + System.identityHashCode(s) +

                                           " vs \"" + i + "\" @ " + System.identityHashCode(i));

            }

        }

        // We have tried to use ClassFileLoadHook to replace critical library classes (which may

        // may not have succeeded, depending on whether the agent has requested

        // can_generate_all_class_hook_events/can_generate_early_class_hook_events capabilities).

        //

        // In any case, the JVM should have started properly (perhaps with CDS disabled) and

        // the above operations should succeed.

        System.out.println("If I can come to here without crashing, things should be OK");

    }

}