/* * Copyright 2003-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, * CA 95054 USA or visit www.sun.com if you need additional information or * have any questions. * */ # include "incls/_precompiled.incl" # include "incls/_loaderConstraints.cpp.incl" LoaderConstraintTable::LoaderConstraintTable(int nof_buckets) : Hashtable(nof_buckets, sizeof(LoaderConstraintEntry)) {}; LoaderConstraintEntry* LoaderConstraintTable::new_entry( unsigned int hash, symbolOop name, klassOop klass, int num_loaders, int max_loaders) { LoaderConstraintEntry* entry; entry = (LoaderConstraintEntry*)Hashtable::new_entry(hash, klass); entry->set_name(name); entry->set_num_loaders(num_loaders); entry->set_max_loaders(max_loaders); return entry; } void LoaderConstraintTable::oops_do(OopClosure* f) { for (int index = 0; index < table_size(); index++) { for (LoaderConstraintEntry* probe = bucket(index); probe != NULL; probe = probe->next()) { f->do_oop((oop*)(probe->name_addr())); if (probe->klass() != NULL) { f->do_oop((oop*)probe->klass_addr()); } for (int n = 0; n < probe->num_loaders(); n++) { if (probe->loader(n) != NULL) { f->do_oop(probe->loader_addr(n)); } } } } } // We must keep the symbolOop used in the name alive. We'll use the // loaders to decide if a particular entry can be purged. void LoaderConstraintTable::always_strong_classes_do(OopClosure* blk) { // We must keep the symbolOop used in the name alive. for (int cindex = 0; cindex < table_size(); cindex++) { for (LoaderConstraintEntry* lc_probe = bucket(cindex); lc_probe != NULL; lc_probe = lc_probe->next()) { assert (lc_probe->name() != NULL, "corrupted loader constraint table"); blk->do_oop((oop*)lc_probe->name_addr()); } } } // 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( symbolHandle name, Handle loader) { unsigned int hash = compute_hash(name); int index = hash_to_index(hash); LoaderConstraintEntry** pp = bucket_addr(index); 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(i) == loader()) { return pp; } } } } pp = p->next_addr(); } return pp; } void LoaderConstraintTable::purge_loader_constraints(BoolObjectClosure* is_alive) { 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; klassOop klass = probe->klass(); // Remove klass that is no longer alive if (klass != NULL && !is_alive->do_object_b(klass)) { 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, SystemDictionary::loader_name(probe->loader(i))); } } } // Remove entries no longer alive from loader array int n = 0; while (n < probe->num_loaders()) { if (probe->loader(n) != NULL) { if (!is_alive->do_object_b(probe->loader(n))) { if (TraceLoaderConstraints) { ResourceMark rm; tty->print_cr("[Purging loader %s from constraint for name %s", SystemDictionary::loader_name(probe->loader(n)), probe->name()->as_C_string() ); } // Compact array int num = probe->num_loaders() - 1; probe->set_num_loaders(num); probe->set_loader(n, probe->loader(num)); probe->set_loader(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, SystemDictionary::loader_name(probe->loader(i))); } } 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()); free_entry(probe); } else { #ifdef ASSERT assert(is_alive->do_object_b(probe->name()), "name should be live"); if (probe->klass() != NULL) { assert(is_alive->do_object_b(probe->klass()), "klass should be live"); } for (n = 0; n < probe->num_loaders(); n++) { if (probe->loader(n) != NULL) { assert(is_alive->do_object_b(probe->loader(n)), "loader should be live"); } } #endif // Go to next entry p = probe->next_addr(); } } } } bool LoaderConstraintTable::add_entry(symbolHandle class_name, klassOop klass1, Handle class_loader1, klassOop klass2, Handle class_loader2) { int failure_code = 0; // encode different reasons for failing if (klass1 != NULL && klass2 != NULL && klass1 != klass2) { failure_code = 1; } else { klassOop 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(oop, 2)); 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, symbolHandle 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; } } klassOop LoaderConstraintTable::find_constrained_klass(symbolHandle name, Handle loader) { LoaderConstraintEntry *p = *(find_loader_constraint(name, loader)); if (p != NULL && p->klass() != 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(); oop* new_loaders = NEW_C_HEAP_ARRAY(oop, n); memcpy(new_loaders, p->loaders(), sizeof(oop) * p->num_loaders()); p->set_max_loaders(n); FREE_C_HEAP_ARRAY(oop, p->loaders()); p->set_loaders(new_loaders); } } void LoaderConstraintTable::extend_loader_constraint(LoaderConstraintEntry* p, Handle loader, klassOop 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, klassOop 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(num, p2->loader(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, SystemDictionary::loader_name(p1->loader(i))); } 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()); free_entry(p2); return; } void LoaderConstraintTable::verify(Dictionary* dictionary) { Thread *thread = Thread::current(); for (int cindex = 0; cindex < _loader_constraint_size; cindex++) { for (LoaderConstraintEntry* probe = bucket(cindex); probe != NULL; probe = probe->next()) { guarantee(probe->name()->is_symbol(), "should be symbol"); if (probe->klass() != NULL) { instanceKlass* ik = instanceKlass::cast(probe->klass()); guarantee(ik->name() == probe->name(), "name should match"); symbolHandle name (thread, ik->name()); Handle loader(thread, ik->class_loader()); unsigned int d_hash = dictionary->compute_hash(name, loader); int d_index = dictionary->hash_to_index(d_hash); klassOop k = dictionary->find_class(d_index, d_hash, name, loader); guarantee(k == probe->klass(), "klass should be in dictionary"); } for (int n = 0; n< probe->num_loaders(); n++) { guarantee(probe->loader(n)->is_oop_or_null(), "should be oop"); } } } } #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(n)->print_value(); tty->print(", "); } tty->cr(); } } } #endif