| /* |
| * Copyright (c) 2003, 2012, 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/classLoaderData.inline.hpp" |
| #include "classfile/loaderConstraints.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 nof_buckets) |
| : Hashtable<Klass*, mtClass>(nof_buckets, sizeof(LoaderConstraintEntry)) {}; |
| |
| |
| LoaderConstraintEntry* LoaderConstraintTable::new_entry( |
| unsigned int hash, Symbol* name, |
| Klass* klass, int num_loaders, |
| int max_loaders) { |
| LoaderConstraintEntry* entry; |
| entry = (LoaderConstraintEntry*)Hashtable<Klass*, 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<Klass*, mtClass>::free_entry(entry); |
| } |
| |
| // Enhanced Class Redefinition support |
| void LoaderConstraintTable::classes_do(KlassClosure* f) { |
| for (int index = 0; index < table_size(); index++) { |
| for (LoaderConstraintEntry* probe = bucket(index); |
| probe != NULL; |
| probe = probe->next()) { |
| if (probe->klass() != NULL) { |
| f->do_klass(probe->klass()); |
| } |
| } |
| } |
| } |
| |
| // 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"); |
| // Remove unloaded entries from constraint table |
| for (int index = 0; index < table_size(); index++) { |
| LoaderConstraintEntry** p = bucket_addr(index); |
| while(*p) { |
| LoaderConstraintEntry* probe = *p; |
| Klass* klass = probe->klass(); |
| // Remove klass that is no longer alive |
| if (klass != NULL && |
| klass->class_loader_data()->is_unloading()) { |
| probe->set_klass(NULL); |
| if (TraceLoaderConstraints) { |
| ResourceMark rm; |
| tty->print_cr("[Purging class object from constraint for name %s," |
| " loader list:", |
| probe->name()->as_C_string()); |
| for (int i = 0; i < probe->num_loaders(); i++) { |
| tty->print_cr("[ [%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 (TraceLoaderConstraints) { |
| ResourceMark rm; |
| tty->print_cr("[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 (TraceLoaderConstraints) { |
| ResourceMark rm; |
| tty->print_cr("[New loader list:"); |
| for (int i = 0; i < probe->num_loaders(); i++) { |
| tty->print_cr("[ [%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 (TraceLoaderConstraints) { |
| ResourceMark rm; |
| tty->print("[Purging complete constraint for name %s\n", |
| probe->name()->as_C_string()); |
| } |
| |
| // Purge entry |
| *p = probe->next(); |
| FREE_C_HEAP_ARRAY(oop, probe->loaders(), mtClass); |
| 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(); |
| } |
| } |
| } |
| } |
| |
| bool LoaderConstraintTable::add_entry(Symbol* class_name, |
| Klass* klass1, Handle class_loader1, |
| Klass* klass2, Handle class_loader2) { |
| int failure_code = 0; // encode different reasons for failing |
| |
| if (klass1 != NULL && klass2 != NULL && klass1 != klass2) { |
| failure_code = 1; |
| } else { |
| Klass* 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()) { |
| failure_code = 2; |
| } |
| } 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()) { |
| failure_code = 3; |
| } |
| } else { |
| klass = (*pp2)->klass(); |
| } |
| } |
| |
| if (failure_code == 0) { |
| 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 (TraceLoaderConstraints) { |
| ResourceMark rm; |
| tty->print("[Adding new constraint for name: %s, loader[0]: %s," |
| " loader[1]: %s ]\n", |
| 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 (TraceLoaderConstraints) { |
| ResourceMark rm; |
| tty->print("[Setting class object in existing constraint for" |
| " name: %s and loader %s ]\n", |
| 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); |
| } |
| } |
| } |
| |
| if (failure_code != 0 && TraceLoaderConstraints) { |
| ResourceMark rm; |
| const char* reason = ""; |
| switch(failure_code) { |
| case 1: reason = "the class objects presented by loader[0] and loader[1]" |
| " are different"; break; |
| case 2: reason = "the class object presented by loader[0] does not match" |
| " the stored class object in the constraint"; break; |
| case 3: reason = "the class object presented by loader[1] does not match" |
| " the stored class object in the constraint"; break; |
| default: reason = "unknown reason code"; |
| } |
| tty->print("[Failed to add constraint for name: %s, loader[0]: %s," |
| " loader[1]: %s, Reason: %s ]\n", |
| class_name->as_C_string(), |
| SystemDictionary::loader_name(class_loader1()), |
| SystemDictionary::loader_name(class_loader2()), |
| reason |
| ); |
| } |
| |
| return failure_code == 0; |
| } |
| |
| |
| // return true if the constraint was updated, false if the constraint is |
| // violated |
| bool LoaderConstraintTable::check_or_update(instanceKlassHandle k, |
| Handle loader, |
| Symbol* name) { |
| LoaderConstraintEntry* p = *(find_loader_constraint(name, loader)); |
| if (p && p->klass() != NULL && p->klass() != k()) { |
| if (TraceLoaderConstraints) { |
| ResourceMark rm; |
| tty->print("[Constraint check failed for name %s, loader %s: " |
| "the presented class object differs from that stored ]\n", |
| name->as_C_string(), |
| SystemDictionary::loader_name(loader())); |
| } |
| return false; |
| } else { |
| if (p && p->klass() == NULL) { |
| p->set_klass(k()); |
| if (TraceLoaderConstraints) { |
| ResourceMark rm; |
| tty->print("[Updating constraint for name %s, loader %s, " |
| "by setting class object ]\n", |
| name->as_C_string(), |
| SystemDictionary::loader_name(loader())); |
| } |
| } |
| return true; |
| } |
| } |
| |
| Klass* LoaderConstraintTable::find_constrained_klass(Symbol* name, |
| Handle loader) { |
| LoaderConstraintEntry *p = *(find_loader_constraint(name, loader)); |
| if (p != NULL && p->klass() != NULL) { |
| if (p->klass()->oop_is_instance() && !InstanceKlass::cast(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(), mtClass); |
| p->set_loaders(new_loaders); |
| } |
| } |
| |
| |
| void LoaderConstraintTable::extend_loader_constraint(LoaderConstraintEntry* p, |
| Handle loader, |
| Klass* klass) { |
| ensure_loader_constraint_capacity(p, 1); |
| int num = p->num_loaders(); |
| p->set_loader(num, loader()); |
| p->set_num_loaders(num + 1); |
| if (TraceLoaderConstraints) { |
| ResourceMark rm; |
| tty->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 ]\n" : " ]\n") |
| ); |
| } |
| 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, |
| Klass* 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); |
| } |
| |
| if (TraceLoaderConstraints) { |
| ResourceMark rm; |
| tty->print_cr("[Merged constraints for name %s, new loader list:", |
| p1->name()->as_C_string() |
| ); |
| |
| for (int i = 0; i < p1->num_loaders(); i++) { |
| tty->print_cr("[ [%d]: %s", i, |
| p1->loader_data(i)->loader_name()); |
| } |
| if (p1->klass() == NULL) { |
| tty->print_cr("[... 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(), mtClass); |
| free_entry(p2); |
| return; |
| } |
| |
| |
| void LoaderConstraintTable::verify(Dictionary* dictionary, |
| PlaceholderTable* placeholders) { |
| Thread *thread = Thread::current(); |
| for (int cindex = 0; cindex < _loader_constraint_size; cindex++) { |
| for (LoaderConstraintEntry* probe = bucket(cindex); |
| probe != NULL; |
| probe = probe->next()) { |
| if (probe->klass() != NULL) { |
| InstanceKlass* ik = InstanceKlass::cast(probe->klass()); |
| guarantee(ik->name() == probe->name(), "name should match"); |
| Symbol* name = ik->name(); |
| ClassLoaderData* loader_data = ik->class_loader_data(); |
| unsigned int d_hash = dictionary->compute_hash(name, loader_data); |
| int d_index = dictionary->hash_to_index(d_hash); |
| Klass* k = dictionary->find_class(d_index, d_hash, name, loader_data); |
| if (k != NULL) { |
| // We found the class in the system 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 system dictionary, it |
| // has to be in the placeholders table. |
| unsigned int p_hash = placeholders->compute_hash(name, loader_data); |
| 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"); |
| } |
| } |
| } |
| } |
| |
| #ifndef PRODUCT |
| |
| // Called with the system dictionary lock held |
| void LoaderConstraintTable::print() { |
| ResourceMark rm; |
| |
| assert_locked_or_safepoint(SystemDictionary_lock); |
| tty->print_cr("Java loader constraints (entries=%d)", _loader_constraint_size); |
| for (int cindex = 0; cindex < _loader_constraint_size; cindex++) { |
| for (LoaderConstraintEntry* probe = bucket(cindex); |
| probe != NULL; |
| probe = probe->next()) { |
| tty->print("%4d: ", cindex); |
| probe->name()->print(); |
| tty->print(" , loaders:"); |
| for (int n = 0; n < probe->num_loaders(); n++) { |
| probe->loader_data(n)->print_value(); |
| tty->print(", "); |
| } |
| tty->cr(); |
| } |
| } |
| } |
| #endif |
