8212117: Class.forName may return a reference to a loaded but not linked Class
Reviewed-by: dholmes, mchung
--- a/make/hotspot/symbols/symbols-unix Mon Sep 09 18:23:39 2019 +0100
+++ b/make/hotspot/symbols/symbols-unix Mon Sep 09 11:04:04 2019 -0700
@@ -1,5 +1,5 @@
#
-# Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
# DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
#
# This code is free software; you can redistribute it and/or modify it
@@ -149,6 +149,7 @@
JVM_IsThreadAlive
JVM_IsVMGeneratedMethodIx
JVM_LatestUserDefinedLoader
+JVM_LinkClass
JVM_LoadLibrary
JVM_MaxMemory
JVM_MaxObjectInspectionAge
--- a/src/hotspot/share/include/jvm.h Mon Sep 09 18:23:39 2019 +0100
+++ b/src/hotspot/share/include/jvm.h Mon Sep 09 11:04:04 2019 -0700
@@ -345,6 +345,11 @@
JNIEXPORT jclass JNICALL
JVM_FindPrimitiveClass(JNIEnv *env, const char *utf);
+/*
+ * Link the 'arg' class
+ */
+JNIEXPORT void JNICALL
+JVM_LinkClass(JNIEnv *env, jclass classClass, jclass arg);
/*
* Find a class from a boot class loader. Returns NULL if class not found.
--- a/src/hotspot/share/prims/jni.cpp Mon Sep 09 18:23:39 2019 +0100
+++ b/src/hotspot/share/prims/jni.cpp Mon Sep 09 11:04:04 2019 -0700
@@ -417,7 +417,7 @@
}
TempNewSymbol sym = SymbolTable::new_symbol(name);
- result = find_class_from_class_loader(env, sym, true, loader,
+ result = find_class_from_class_loader(env, sym, true, true, loader,
protection_domain, true, thread);
if (log_is_enabled(Debug, class, resolve) && result != NULL) {
@@ -3289,7 +3289,7 @@
Handle protection_domain; // null protection domain
TempNewSymbol sym = SymbolTable::new_symbol(name);
- jclass result = find_class_from_class_loader(env, sym, true, loader, protection_domain, true, CHECK_NULL);
+ jclass result = find_class_from_class_loader(env, sym, true, true, loader, protection_domain, true, CHECK_NULL);
if (log_is_enabled(Debug, class, resolve) && result != NULL) {
trace_class_resolution(java_lang_Class::as_Klass(JNIHandles::resolve_non_null(result)));
--- a/src/hotspot/share/prims/jvm.cpp Mon Sep 09 18:23:39 2019 +0100
+++ b/src/hotspot/share/prims/jvm.cpp Mon Sep 09 11:04:04 2019 -0700
@@ -717,6 +717,17 @@
// Misc. class handling ///////////////////////////////////////////////////////////
+JVM_ENTRY(void, JVM_LinkClass(JNIEnv* env, jclass classClass, jclass arg))
+ JVMWrapper("JVM_LinkClass");
+
+ oop r = JNIHandles::resolve(arg);
+ Klass* klass = java_lang_Class::as_Klass(r);
+
+ if (!ClassForNameDeferLinking && klass->is_instance_klass()) {
+ InstanceKlass::cast(klass)->link_class(CHECK);
+ }
+JVM_END
+
JVM_ENTRY(jclass, JVM_GetCallerClass(JNIEnv* env))
JVMWrapper("JVM_GetCallerClass");
@@ -827,9 +838,10 @@
Handle h_loader(THREAD, loader_oop);
Handle h_prot(THREAD, protection_domain);
- jclass result = find_class_from_class_loader(env, h_name, init, h_loader,
+
+ jboolean link = !ClassForNameDeferLinking;
+ jclass result = find_class_from_class_loader(env, h_name, init, link, h_loader,
h_prot, false, THREAD);
-
if (log_is_enabled(Debug, class, resolve) && result != NULL) {
trace_class_resolution(java_lang_Class::as_Klass(JNIHandles::resolve_non_null(result)));
}
@@ -866,7 +878,7 @@
}
Handle h_loader(THREAD, class_loader);
Handle h_prot (THREAD, protection_domain);
- jclass result = find_class_from_class_loader(env, h_name, init, h_loader,
+ jclass result = find_class_from_class_loader(env, h_name, init, false, h_loader,
h_prot, true, thread);
if (log_is_enabled(Debug, class, resolve) && result != NULL) {
@@ -3424,9 +3436,12 @@
// Shared JNI/JVM entry points //////////////////////////////////////////////////////////////
-jclass find_class_from_class_loader(JNIEnv* env, Symbol* name, jboolean init,
+jclass find_class_from_class_loader(JNIEnv* env, Symbol* name, jboolean init, jboolean link,
Handle loader, Handle protection_domain,
jboolean throwError, TRAPS) {
+ // Initialization also implies linking - check for coherent args
+ assert((init && link) || !init, "incorrect use of init/link arguments");
+
// Security Note:
// The Java level wrapper will perform the necessary security check allowing
// us to pass the NULL as the initiating class loader. The VM is responsible for
@@ -3435,9 +3450,11 @@
// if there is no security manager in 3-arg Class.forName().
Klass* klass = SystemDictionary::resolve_or_fail(name, loader, protection_domain, throwError != 0, CHECK_NULL);
- // Check if we should initialize the class
+ // Check if we should initialize the class (which implies linking), or just link it
if (init && klass->is_instance_klass()) {
klass->initialize(CHECK_NULL);
+ } else if (link && klass->is_instance_klass()) {
+ InstanceKlass::cast(klass)->link_class(CHECK_NULL);
}
return (jclass) JNIHandles::make_local(env, klass->java_mirror());
}
--- a/src/hotspot/share/prims/jvm_misc.hpp Mon Sep 09 18:23:39 2019 +0100
+++ b/src/hotspot/share/prims/jvm_misc.hpp Mon Sep 09 11:04:04 2019 -0700
@@ -31,7 +31,8 @@
// Useful entry points shared by JNI and JVM interface.
// We do not allow real JNI or JVM entry point to call each other.
-jclass find_class_from_class_loader(JNIEnv* env, Symbol* name, jboolean init, Handle loader, Handle protection_domain, jboolean throwError, TRAPS);
+jclass find_class_from_class_loader(JNIEnv* env, Symbol* name, jboolean init, jboolean link,
+ Handle loader, Handle protection_domain, jboolean throwError, TRAPS);
void trace_class_resolution(Klass* to_class);
--- a/src/hotspot/share/runtime/globals.hpp Mon Sep 09 18:23:39 2019 +0100
+++ b/src/hotspot/share/runtime/globals.hpp Mon Sep 09 11:04:04 2019 -0700
@@ -2164,6 +2164,9 @@
"Maximum total size of NIO direct-buffer allocations") \
range(0, max_jlong) \
\
+ product(bool, ClassForNameDeferLinking, false, \
+ "Revert to not linking in Class.forName()") \
+ \
/* Flags used for temporary code during development */ \
\
diagnostic(bool, UseNewCode, false, \
--- a/src/java.base/share/classes/java/lang/Class.java Mon Sep 09 18:23:39 2019 +0100
+++ b/src/java.base/share/classes/java/lang/Class.java Mon Sep 09 11:04:04 2019 -0700
@@ -392,6 +392,10 @@
*
* @see java.lang.Class#forName(String)
* @see java.lang.ClassLoader
+ *
+ * @jls 12.2 Loading of Classes and Interfaces
+ * @jls 12.3 Linking of Classes and Interfaces
+ * @jls 12.4 Initialization of Classes and Interfaces
* @since 1.2
*/
@CallerSensitive
@@ -438,6 +442,10 @@
* <p> This method does not check whether the requested class is
* accessible to its caller. </p>
*
+ * <p> Note that this method throws errors related to loading and linking as
+ * specified in Sections 12.2 and 12.3 of <em>The Java Language
+ * Specification</em>.
+ *
* @apiNote
* This method returns {@code null} on failure rather than
* throwing a {@link ClassNotFoundException}, as is done by
@@ -465,6 +473,8 @@
* in a module.</li>
* </ul>
*
+ * @jls 12.2 Loading of Classes and Interfaces
+ * @jls 12.3 Linking of Classes and Interfaces
* @since 9
* @spec JPMS
*/
@@ -488,13 +498,21 @@
cl = module.getClassLoader();
}
+ Class<?> ret;
if (cl != null) {
- return cl.loadClass(module, name);
+ ret = cl.loadClass(module, name);
} else {
- return BootLoader.loadClass(module, name);
+ ret = BootLoader.loadClass(module, name);
}
+ if (ret != null) {
+ // The loaded class should also be linked
+ linkClass(ret);
+ }
+ return ret;
}
+ private static native void linkClass(Class<?> c);
+
/**
* Creates a new instance of the class represented by this {@code Class}
* object. The class is instantiated as if by a {@code new}
--- a/src/java.base/share/classes/java/lang/invoke/MethodHandles.java Mon Sep 09 18:23:39 2019 +0100
+++ b/src/java.base/share/classes/java/lang/invoke/MethodHandles.java Mon Sep 09 11:04:04 2019 -0700
@@ -1927,12 +1927,17 @@
}
/**
- * Looks up a class by name from the lookup context defined by this {@code Lookup} object. The static
+ * Looks up a class by name from the lookup context defined by this {@code Lookup} object.
+ * This method attempts to locate, load, and link the class, and then determines whether
+ * the class is accessible to this {@code Lookup} object. The static
* initializer of the class is not run.
* <p>
* The lookup context here is determined by the {@linkplain #lookupClass() lookup class}, its class
- * loader, and the {@linkplain #lookupModes() lookup modes}. In particular, the method first attempts to
- * load the requested class, and then determines whether the class is accessible to this lookup object.
+ * loader, and the {@linkplain #lookupModes() lookup modes}.
+ * <p>
+ * Note that this method throws errors related to loading and linking as
+ * specified in Sections 12.2 and 12.3 of <em>The Java Language
+ * Specification</em>.
*
* @param targetName the fully qualified name of the class to be looked up.
* @return the requested class.
@@ -1944,6 +1949,9 @@
* modes.
* @exception SecurityException if a security manager is present and it
* <a href="MethodHandles.Lookup.html#secmgr">refuses access</a>
+ *
+ * @jls 12.2 Loading of Classes and Interfaces
+ * @jls 12.3 Linking of Classes and Interfaces
* @since 9
*/
public Class<?> findClass(String targetName) throws ClassNotFoundException, IllegalAccessException {
--- a/src/java.base/share/classes/sun/launcher/LauncherHelper.java Mon Sep 09 18:23:39 2019 +0100
+++ b/src/java.base/share/classes/sun/launcher/LauncherHelper.java Mon Sep 09 11:04:04 2019 -0700
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@@ -62,6 +62,7 @@
import java.nio.file.DirectoryStream;
import java.nio.file.Files;
import java.nio.file.Path;
+import java.security.AccessControlException;
import java.text.Normalizer;
import java.text.MessageFormat;
import java.util.ArrayList;
@@ -724,6 +725,9 @@
} catch (LinkageError le) {
abort(null, "java.launcher.module.error3", mainClass, m.getName(),
le.getClass().getName() + ": " + le.getLocalizedMessage());
+ } catch (AccessControlException ace) {
+ abort(ace, "java.launcher.module.error5", mainClass, m.getName(),
+ ace.getClass().getName(), ace.getLocalizedMessage());
}
if (c == null) {
abort(null, "java.launcher.module.error2", mainClass, mainModule);
@@ -780,6 +784,9 @@
} catch (LinkageError le) {
abort(le, "java.launcher.cls.error6", cn,
le.getClass().getName() + ": " + le.getLocalizedMessage());
+ } catch (AccessControlException ace) {
+ abort(ace, "java.launcher.cls.error7", cn,
+ ace.getClass().getName(), ace.getLocalizedMessage());
}
return mainClass;
}
--- a/src/java.base/share/native/libjava/Class.c Mon Sep 09 18:23:39 2019 +0100
+++ b/src/java.base/share/native/libjava/Class.c Mon Sep 09 11:04:04 2019 -0700
@@ -76,6 +76,7 @@
{"getRawTypeAnnotations", "()" BA, (void *)&JVM_GetClassTypeAnnotations},
{"getNestHost0", "()" CLS, (void *)&JVM_GetNestHost},
{"getNestMembers0", "()[" CLS, (void *)&JVM_GetNestMembers},
+ {"linkClass", "(" CLS ")V", (void *)&JVM_LinkClass},
};
#undef OBJ
--- a/test/hotspot/jtreg/gc/logging/TestMetaSpaceLog.java Mon Sep 09 18:23:39 2019 +0100
+++ b/test/hotspot/jtreg/gc/logging/TestMetaSpaceLog.java Mon Sep 09 11:04:04 2019 -0700
@@ -130,7 +130,7 @@
public static void loadClass(WhiteBox wb) {
try {
URLClassLoader ucl = new URLClassLoader(urls);
- Class.forName("case00", false, ucl);
+ ucl.loadClass("case00");
} catch (Exception e) {
e.printStackTrace();
}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/serviceability/jvmti/ClassStatus/ClassStatus.java Mon Sep 09 11:04:04 2019 -0700
@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * 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.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8212117
+ * @summary Verify JVMTI GetClassStatus returns CLASS_PREPARE after call to Class.forName()
+ * @run main/othervm/native -agentlib:ClassStatus ClassStatus
+ */
+
+
+public class ClassStatus {
+ static {
+ try {
+ System.out.println("ClassStatus static block");
+ System.loadLibrary("ClassStatus");
+ } catch (UnsatisfiedLinkError ule) {
+ System.err.println("Could not load ClassStatus library");
+ System.err.println("java.library.path: "
+ + System.getProperty("java.library.path"));
+ throw ule;
+ }
+ }
+
+ static native int check(Class klass);
+
+ public static void main(String[] args) throws ClassNotFoundException {
+ ClassLoader loader = ClassStatus.class.getClassLoader();
+ Module module = loader.getUnnamedModule();
+
+ // Load class, but don't initialize it
+ Class foo2 = Class.forName(module, "Foo2");
+ Class foo3 = Class.forName("Foo3", false, loader);
+
+ System.out.println("Loaded: " + foo2);
+ System.out.println("Loaded: " + foo3);
+
+ int status2 = check(foo2);
+ int status3 = check(foo3);
+
+ new Foo2().bar();
+ new Foo3().bar();
+
+ if (status2 != 0) {
+ System.out.println("The agent returned non-zero exit status for Foo2: " + status2);
+ }
+ if (status3 != 0) {
+ System.out.println("The agent returned non-zero exit status for Foo3: " + status3);
+ }
+ if (status2 != 0 || status3 != 0) {
+ throw new RuntimeException("Non-zero status returned from the agent");
+ }
+ }
+}
+
+class Foo2 {
+ static {
+ System.out.println("Foo2 is initialized");
+ }
+ void bar() {
+ System.out.println("Foo2.bar() is called");
+ }
+}
+
+class Foo3 {
+ static {
+ System.out.println("Foo3 is initialized");
+ }
+ void bar() {
+ System.out.println("Foo3.bar() is called");
+ }
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/serviceability/jvmti/ClassStatus/libClassStatus.c Mon Sep 09 11:04:04 2019 -0700
@@ -0,0 +1,173 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * 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.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "jvmti.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef JNI_ENV_ARG
+
+#ifdef __cplusplus
+#define JNI_ENV_ARG(x, y) y
+#define JNI_ENV_PTR(x) x
+#else
+#define JNI_ENV_ARG(x,y) x, y
+#define JNI_ENV_PTR(x) (*x)
+#endif
+
+#endif
+
+#define PASSED 0
+#define FAILED 2
+
+static jvmtiEnv* jvmti = NULL;
+
+static jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved);
+
+JNIEXPORT jint JNICALL
+Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
+ return Agent_Initialize(jvm, options, reserved);
+}
+
+JNIEXPORT jint JNICALL
+Agent_OnAttach(JavaVM *jvm, char *options, void *reserved) {
+ return Agent_Initialize(jvm, options, reserved);
+}
+
+JNIEXPORT jint JNICALL
+JNI_OnLoad(JavaVM *jvm, void *reserved) {
+ return JNI_VERSION_9;
+}
+
+static void
+check_jvmti_error(jvmtiEnv *jvmti, char* fname, jvmtiError err) {
+ if (err != JVMTI_ERROR_NONE) {
+ printf(" ## %s error: %d\n", fname, err);
+ fflush(0);
+ exit(err);
+ }
+}
+
+static char*
+get_class_signature(jvmtiEnv *jvmti, jclass klass) {
+ char* sign = NULL;
+ jvmtiError err = (*jvmti)->GetClassSignature(jvmti, klass, &sign, NULL);
+
+ check_jvmti_error(jvmti, "GetClassSignature", err);
+ return sign;
+}
+
+static jboolean
+is_class_status_prepared(jvmtiEnv *jvmti, jclass klass) {
+ char* sign = get_class_signature(jvmti, klass);
+ jint status = 0;
+ jvmtiError err = (*jvmti)->GetClassStatus(jvmti, klass, &status);
+
+ check_jvmti_error(jvmti, "GetClassStatus", err);
+ printf(" Class %s status: 0x%08x\n", sign, status);
+ printf(" Class %s is prepared: %d\n", sign, (status & JVMTI_CLASS_STATUS_PREPARED) != 0);
+ fflush(0);
+
+ return (status & JVMTI_CLASS_STATUS_PREPARED) != 0;
+}
+
+static jboolean
+is_class_in_loaded_classes(JNIEnv *env, jclass klass) {
+ char* sign = get_class_signature(jvmti, klass);
+ jint class_count = 0;
+ jclass* classes = NULL;
+ jvmtiError err = (*jvmti)->GetLoadedClasses(jvmti, &class_count, &classes);
+
+ check_jvmti_error(jvmti, "GetLoadedClasses", err);
+
+ for (int i = 0; i < class_count; i++) {
+ jclass cls = classes[i];
+ jboolean same = (*env)->IsSameObject(env, cls, klass);
+ if (same) {
+ printf("Found class %s in the list of loaded classes\n", sign);
+ fflush(0);
+ return JNI_TRUE;
+ }
+ }
+ printf("Error: Have not found class %s in the list of loaded classes\n", sign);
+ fflush(0);
+ return JNI_FALSE;
+}
+
+static void JNICALL
+ClassPrepare(jvmtiEnv *jvmti, JNIEnv *env, jthread thread, jclass klass) {
+ char* sign = get_class_signature(jvmti, klass);
+
+ sign = (sign == NULL) ? "NULL" : sign;
+
+ if (strcmp(sign, "LFoo2;") == 0 || strcmp(sign, "LFoo3;") == 0) {
+ printf("ClassPrepare event for class: %s\n", sign);
+ fflush(0);
+ }
+}
+
+static jint
+Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
+ jvmtiError err;
+ jint size;
+ jint res;
+ jvmtiEventCallbacks callbacks;
+
+ printf("Agent_Initialize started\n");
+ fflush(0);
+ res = JNI_ENV_PTR(jvm)->GetEnv(JNI_ENV_ARG(jvm, (void **) &jvmti), JVMTI_VERSION_9);
+ if (res != JNI_OK || jvmti == NULL) {
+ printf("## Agent_Initialize: Error in GetEnv: res: %d, jvmti env: %p\n", res, jvmti);
+ return JNI_ERR;
+ }
+
+ size = (jint)sizeof(callbacks);
+ memset(&callbacks, 0, size);
+ callbacks.ClassPrepare = ClassPrepare;
+
+ err = (*jvmti)->SetEventCallbacks(jvmti, &callbacks, size);
+ check_jvmti_error(jvmti, "## Agent_Initialize: SetEventCallbacks", err);
+
+ err = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_CLASS_PREPARE, NULL);
+ check_jvmti_error(jvmti, "## Agent_Initialize: SetEventNotificationMode CLASS_PREPARE", err);
+ return JNI_OK;
+}
+
+JNIEXPORT jint JNICALL
+Java_ClassStatus_check(JNIEnv *env, jclass cls, jclass klass) {
+ if (is_class_in_loaded_classes(env, klass) != JNI_TRUE ||
+ is_class_status_prepared(jvmti, klass) != JNI_TRUE) {
+ return FAILED;
+ }
+ return PASSED;
+}
+
+#ifdef __cplusplus
+}
+#endif