--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/classfile/loaderConstraints.cpp Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,489 @@
+/*
+ * Copyright (c) 2003, 2017, 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 "precompiled.hpp"
+#include "classfile/dictionary.hpp"
+#include "classfile/classLoaderData.inline.hpp"
+#include "classfile/loaderConstraints.hpp"
+#include "logging/log.hpp"
+#include "memory/resourceArea.hpp"
+#include "oops/oop.inline.hpp"
+#include "runtime/handles.inline.hpp"
+#include "runtime/safepoint.hpp"
+#include "utilities/hashtable.inline.hpp"
+
+void LoaderConstraintEntry::set_loader(int i, oop p) {
+ set_loader_data(i, ClassLoaderData::class_loader_data(p));
+}
+
+LoaderConstraintTable::LoaderConstraintTable(int table_size)
+ : Hashtable<InstanceKlass*, mtClass>(table_size, sizeof(LoaderConstraintEntry)) {};
+
+
+LoaderConstraintEntry* LoaderConstraintTable::new_entry(
+ unsigned int hash, Symbol* name,
+ InstanceKlass* klass, int num_loaders,
+ int max_loaders) {
+ LoaderConstraintEntry* entry;
+ entry = (LoaderConstraintEntry*)Hashtable<InstanceKlass*, mtClass>::new_entry(hash, klass);
+ entry->set_name(name);
+ entry->set_num_loaders(num_loaders);
+ entry->set_max_loaders(max_loaders);
+ return entry;
+}
+
+void LoaderConstraintTable::free_entry(LoaderConstraintEntry *entry) {
+ // decrement name refcount before freeing
+ entry->name()->decrement_refcount();
+ Hashtable<InstanceKlass*, mtClass>::free_entry(entry);
+}
+
+// The loaderConstraintTable must always be accessed with the
+// SystemDictionary lock held. This is true even for readers as
+// entries in the table could be being dynamically resized.
+
+LoaderConstraintEntry** LoaderConstraintTable::find_loader_constraint(
+ Symbol* name, Handle loader) {
+
+ unsigned int hash = compute_hash(name);
+ int index = hash_to_index(hash);
+ LoaderConstraintEntry** pp = bucket_addr(index);
+ ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(loader());
+
+ while (*pp) {
+ LoaderConstraintEntry* p = *pp;
+ if (p->hash() == hash) {
+ if (p->name() == name) {
+ for (int i = p->num_loaders() - 1; i >= 0; i--) {
+ if (p->loader_data(i) == loader_data) {
+ return pp;
+ }
+ }
+ }
+ }
+ pp = p->next_addr();
+ }
+ return pp;
+}
+
+
+void LoaderConstraintTable::purge_loader_constraints() {
+ assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
+ LogTarget(Info, class, loader, constraints) lt;
+ // Remove unloaded entries from constraint table
+ for (int index = 0; index < table_size(); index++) {
+ LoaderConstraintEntry** p = bucket_addr(index);
+ while(*p) {
+ LoaderConstraintEntry* probe = *p;
+ InstanceKlass* klass = probe->klass();
+ // Remove klass that is no longer alive
+ if (klass != NULL &&
+ klass->class_loader_data()->is_unloading()) {
+ probe->set_klass(NULL);
+ if (lt.is_enabled()) {
+ ResourceMark rm;
+ lt.print("purging class object from constraint for name %s,"
+ " loader list:",
+ probe->name()->as_C_string());
+ for (int i = 0; i < probe->num_loaders(); i++) {
+ lt.print(" [%d]: %s", i,
+ probe->loader_data(i)->loader_name());
+ }
+ }
+ }
+ // Remove entries no longer alive from loader array
+ int n = 0;
+ while (n < probe->num_loaders()) {
+ if (probe->loader_data(n)->is_unloading()) {
+ if (lt.is_enabled()) {
+ ResourceMark rm;
+ lt.print("purging loader %s from constraint for name %s",
+ probe->loader_data(n)->loader_name(),
+ probe->name()->as_C_string()
+ );
+ }
+
+ // Compact array
+ int num = probe->num_loaders() - 1;
+ probe->set_num_loaders(num);
+ probe->set_loader_data(n, probe->loader_data(num));
+ probe->set_loader_data(num, NULL);
+
+ if (lt.is_enabled()) {
+ ResourceMark rm;
+ lt.print("new loader list:");
+ for (int i = 0; i < probe->num_loaders(); i++) {
+ lt.print(" [%d]: %s", i,
+ probe->loader_data(i)->loader_name());
+ }
+ }
+
+ continue; // current element replaced, so restart without
+ // incrementing n
+ }
+ n++;
+ }
+ // Check whether entry should be purged
+ if (probe->num_loaders() < 2) {
+ if (lt.is_enabled()) {
+ ResourceMark rm;
+ lt.print("purging complete constraint for name %s",
+ probe->name()->as_C_string());
+ }
+
+ // Purge entry
+ *p = probe->next();
+ FREE_C_HEAP_ARRAY(oop, probe->loaders());
+ free_entry(probe);
+ } else {
+#ifdef ASSERT
+ if (probe->klass() != NULL) {
+ ClassLoaderData* loader_data =
+ probe->klass()->class_loader_data();
+ assert(!loader_data->is_unloading(), "klass should be live");
+ }
+#endif
+ // Go to next entry
+ p = probe->next_addr();
+ }
+ }
+ }
+}
+
+void log_ldr_constraint_msg(Symbol* class_name, const char* reason,
+ Handle class_loader1, Handle class_loader2) {
+ LogTarget(Info, class, loader, constraints) lt;
+ if (lt.is_enabled()) {
+ ResourceMark rm;
+ lt.print("Failed to add constraint for name: %s, loader[0]: %s,"
+ " loader[1]: %s, Reason: %s",
+ class_name->as_C_string(),
+ SystemDictionary::loader_name(class_loader1()),
+ SystemDictionary::loader_name(class_loader2()),
+ reason);
+ }
+}
+
+bool LoaderConstraintTable::add_entry(Symbol* class_name,
+ InstanceKlass* klass1, Handle class_loader1,
+ InstanceKlass* klass2, Handle class_loader2) {
+ LogTarget(Info, class, loader, constraints) lt;
+ if (klass1 != NULL && klass2 != NULL) {
+ if (klass1 == klass2) {
+ // Same type already loaded in both places. There is no need for any constraint.
+ return true;
+ } else {
+ log_ldr_constraint_msg(class_name,
+ "The class objects presented by loader[0] and loader[1] "
+ "are different",
+ class_loader1, class_loader2);
+ return false;
+ }
+ }
+
+ InstanceKlass* klass = klass1 != NULL ? klass1 : klass2;
+ LoaderConstraintEntry** pp1 = find_loader_constraint(class_name, class_loader1);
+ if (*pp1 != NULL && (*pp1)->klass() != NULL) {
+ if (klass != NULL) {
+ if (klass != (*pp1)->klass()) {
+ log_ldr_constraint_msg(class_name,
+ "The class object presented by loader[0] does not match "
+ "the stored class object in the constraint",
+ class_loader1, class_loader2);
+ return false;
+ }
+ } else {
+ klass = (*pp1)->klass();
+ }
+ }
+
+ LoaderConstraintEntry** pp2 = find_loader_constraint(class_name, class_loader2);
+ if (*pp2 != NULL && (*pp2)->klass() != NULL) {
+ if (klass != NULL) {
+ if (klass != (*pp2)->klass()) {
+ log_ldr_constraint_msg(class_name,
+ "The class object presented by loader[1] does not match "
+ "the stored class object in the constraint",
+ class_loader1, class_loader2);
+ return false;
+ }
+ } else {
+ klass = (*pp2)->klass();
+ }
+ }
+
+ if (*pp1 == NULL && *pp2 == NULL) {
+ unsigned int hash = compute_hash(class_name);
+ int index = hash_to_index(hash);
+ LoaderConstraintEntry* p;
+ p = new_entry(hash, class_name, klass, 2, 2);
+ p->set_loaders(NEW_C_HEAP_ARRAY(ClassLoaderData*, 2, mtClass));
+ p->set_loader(0, class_loader1());
+ p->set_loader(1, class_loader2());
+ p->set_klass(klass);
+ p->set_next(bucket(index));
+ set_entry(index, p);
+ if (lt.is_enabled()) {
+ ResourceMark rm;
+ lt.print("adding new constraint for name: %s, loader[0]: %s,"
+ " loader[1]: %s",
+ class_name->as_C_string(),
+ SystemDictionary::loader_name(class_loader1()),
+ SystemDictionary::loader_name(class_loader2())
+ );
+ }
+ } else if (*pp1 == *pp2) {
+ /* constraint already imposed */
+ if ((*pp1)->klass() == NULL) {
+ (*pp1)->set_klass(klass);
+ if (lt.is_enabled()) {
+ ResourceMark rm;
+ lt.print("setting class object in existing constraint for"
+ " name: %s and loader %s",
+ class_name->as_C_string(),
+ SystemDictionary::loader_name(class_loader1())
+ );
+ }
+ } else {
+ assert((*pp1)->klass() == klass, "loader constraints corrupted");
+ }
+ } else if (*pp1 == NULL) {
+ extend_loader_constraint(*pp2, class_loader1, klass);
+ } else if (*pp2 == NULL) {
+ extend_loader_constraint(*pp1, class_loader2, klass);
+ } else {
+ merge_loader_constraints(pp1, pp2, klass);
+ }
+
+ return true;
+}
+
+
+// return true if the constraint was updated, false if the constraint is
+// violated
+bool LoaderConstraintTable::check_or_update(InstanceKlass* k,
+ Handle loader,
+ Symbol* name) {
+ LogTarget(Info, class, loader, constraints) lt;
+ LoaderConstraintEntry* p = *(find_loader_constraint(name, loader));
+ if (p && p->klass() != NULL && p->klass() != k) {
+ if (lt.is_enabled()) {
+ ResourceMark rm;
+ lt.print("constraint check failed for name %s, loader %s: "
+ "the presented class object differs from that stored",
+ name->as_C_string(),
+ SystemDictionary::loader_name(loader()));
+ }
+ return false;
+ } else {
+ if (p && p->klass() == NULL) {
+ p->set_klass(k);
+ if (lt.is_enabled()) {
+ ResourceMark rm;
+ lt.print("updating constraint for name %s, loader %s, "
+ "by setting class object",
+ name->as_C_string(),
+ SystemDictionary::loader_name(loader()));
+ }
+ }
+ return true;
+ }
+}
+
+InstanceKlass* LoaderConstraintTable::find_constrained_klass(Symbol* name,
+ Handle loader) {
+ LoaderConstraintEntry *p = *(find_loader_constraint(name, loader));
+ if (p != NULL && p->klass() != NULL) {
+ assert(p->klass()->is_instance_klass(), "sanity");
+ if (!p->klass()->is_loaded()) {
+ // Only return fully loaded classes. Classes found through the
+ // constraints might still be in the process of loading.
+ return NULL;
+ }
+ return p->klass();
+ }
+
+ // No constraints, or else no klass loaded yet.
+ return NULL;
+}
+
+void LoaderConstraintTable::ensure_loader_constraint_capacity(
+ LoaderConstraintEntry *p,
+ int nfree) {
+ if (p->max_loaders() - p->num_loaders() < nfree) {
+ int n = nfree + p->num_loaders();
+ ClassLoaderData** new_loaders = NEW_C_HEAP_ARRAY(ClassLoaderData*, n, mtClass);
+ memcpy(new_loaders, p->loaders(), sizeof(ClassLoaderData*) * p->num_loaders());
+ p->set_max_loaders(n);
+ FREE_C_HEAP_ARRAY(ClassLoaderData*, p->loaders());
+ p->set_loaders(new_loaders);
+ }
+}
+
+
+void LoaderConstraintTable::extend_loader_constraint(LoaderConstraintEntry* p,
+ Handle loader,
+ InstanceKlass* klass) {
+ ensure_loader_constraint_capacity(p, 1);
+ int num = p->num_loaders();
+ p->set_loader(num, loader());
+ p->set_num_loaders(num + 1);
+ LogTarget(Info, class, loader, constraints) lt;
+ if (lt.is_enabled()) {
+ ResourceMark rm;
+ lt.print("extending constraint for name %s by adding loader[%d]: %s %s",
+ p->name()->as_C_string(),
+ num,
+ SystemDictionary::loader_name(loader()),
+ (p->klass() == NULL ? " and setting class object" : "")
+ );
+ }
+ if (p->klass() == NULL) {
+ p->set_klass(klass);
+ } else {
+ assert(klass == NULL || p->klass() == klass, "constraints corrupted");
+ }
+}
+
+
+void LoaderConstraintTable::merge_loader_constraints(
+ LoaderConstraintEntry** pp1,
+ LoaderConstraintEntry** pp2,
+ InstanceKlass* klass) {
+ // make sure *pp1 has higher capacity
+ if ((*pp1)->max_loaders() < (*pp2)->max_loaders()) {
+ LoaderConstraintEntry** tmp = pp2;
+ pp2 = pp1;
+ pp1 = tmp;
+ }
+
+ LoaderConstraintEntry* p1 = *pp1;
+ LoaderConstraintEntry* p2 = *pp2;
+
+ ensure_loader_constraint_capacity(p1, p2->num_loaders());
+
+ for (int i = 0; i < p2->num_loaders(); i++) {
+ int num = p1->num_loaders();
+ p1->set_loader_data(num, p2->loader_data(i));
+ p1->set_num_loaders(num + 1);
+ }
+
+ LogTarget(Info, class, loader, constraints) lt;
+ if (lt.is_enabled()) {
+ ResourceMark rm;
+ lt.print("merged constraints for name %s, new loader list:",
+ p1->name()->as_C_string()
+ );
+
+ for (int i = 0; i < p1->num_loaders(); i++) {
+ lt.print(" [%d]: %s", i,
+ p1->loader_data(i)->loader_name());
+ }
+ if (p1->klass() == NULL) {
+ lt.print("... and setting class object");
+ }
+ }
+
+ // p1->klass() will hold NULL if klass, p2->klass(), and old
+ // p1->klass() are all NULL. In addition, all three must have
+ // matching non-NULL values, otherwise either the constraints would
+ // have been violated, or the constraints had been corrupted (and an
+ // assertion would fail).
+ if (p2->klass() != NULL) {
+ assert(p2->klass() == klass, "constraints corrupted");
+ }
+ if (p1->klass() == NULL) {
+ p1->set_klass(klass);
+ } else {
+ assert(p1->klass() == klass, "constraints corrupted");
+ }
+
+ *pp2 = p2->next();
+ FREE_C_HEAP_ARRAY(oop, p2->loaders());
+ free_entry(p2);
+ return;
+}
+
+
+void LoaderConstraintTable::verify(PlaceholderTable* placeholders) {
+ Thread *thread = Thread::current();
+ for (int cindex = 0; cindex < table_size(); cindex++) {
+ for (LoaderConstraintEntry* probe = bucket(cindex);
+ probe != NULL;
+ probe = probe->next()) {
+ if (probe->klass() != NULL) {
+ InstanceKlass* ik = probe->klass();
+ guarantee(ik->name() == probe->name(), "name should match");
+ Symbol* name = ik->name();
+ ClassLoaderData* loader_data = ik->class_loader_data();
+ Dictionary* dictionary = loader_data->dictionary();
+ unsigned int d_hash = dictionary->compute_hash(name);
+ int d_index = dictionary->hash_to_index(d_hash);
+ InstanceKlass* k = dictionary->find_class(d_index, d_hash, name);
+ if (k != NULL) {
+ // We found the class in the dictionary, so we should
+ // make sure that the Klass* matches what we already have.
+ guarantee(k == probe->klass(), "klass should be in dictionary");
+ } else {
+ // If we don't find the class in the dictionary, it
+ // has to be in the placeholders table.
+ unsigned int p_hash = placeholders->compute_hash(name);
+ int p_index = placeholders->hash_to_index(p_hash);
+ PlaceholderEntry* entry = placeholders->get_entry(p_index, p_hash,
+ name, loader_data);
+
+ // The InstanceKlass might not be on the entry, so the only
+ // thing we can check here is whether we were successful in
+ // finding the class in the placeholders table.
+ guarantee(entry != NULL, "klass should be in the placeholders");
+ }
+ }
+ for (int n = 0; n< probe->num_loaders(); n++) {
+ assert(ClassLoaderDataGraph::contains_loader_data(probe->loader_data(n)), "The loader is missing");
+ }
+ }
+ }
+}
+
+// Called with the system dictionary lock held
+void LoaderConstraintTable::print_on(outputStream* st) const {
+ ResourceMark rm;
+ assert_locked_or_safepoint(SystemDictionary_lock);
+ st->print_cr("Java loader constraints (table_size=%d, constraints=%d)",
+ table_size(), number_of_entries());
+ for (int cindex = 0; cindex < table_size(); cindex++) {
+ for (LoaderConstraintEntry* probe = bucket(cindex);
+ probe != NULL;
+ probe = probe->next()) {
+ st->print("%4d: ", cindex);
+ probe->name()->print_on(st);
+ st->print(" , loaders:");
+ for (int n = 0; n < probe->num_loaders(); n++) {
+ probe->loader_data(n)->print_value_on(st);
+ st->print(", ");
+ }
+ st->cr();
+ }
+ }
+}