duke@435: /*
trims@1907:  * Copyright (c) 2003, 2006, Oracle and/or its affiliates. All rights reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
duke@435:  *
duke@435:  */
duke@435: 
duke@435: # include "incls/_precompiled.incl"
duke@435: # include "incls/_loaderConstraints.cpp.incl"
duke@435: 
duke@435: LoaderConstraintTable::LoaderConstraintTable(int nof_buckets)
duke@435:   : Hashtable(nof_buckets, sizeof(LoaderConstraintEntry)) {};
duke@435: 
duke@435: 
duke@435: LoaderConstraintEntry* LoaderConstraintTable::new_entry(
duke@435:                                  unsigned int hash, symbolOop name,
duke@435:                                  klassOop klass, int num_loaders,
duke@435:                                  int max_loaders) {
duke@435:   LoaderConstraintEntry* entry;
duke@435:   entry = (LoaderConstraintEntry*)Hashtable::new_entry(hash, klass);
duke@435:   entry->set_name(name);
duke@435:   entry->set_num_loaders(num_loaders);
duke@435:   entry->set_max_loaders(max_loaders);
duke@435:   return entry;
duke@435: }
duke@435: 
duke@435: 
duke@435: void LoaderConstraintTable::oops_do(OopClosure* f) {
duke@435:   for (int index = 0; index < table_size(); index++) {
duke@435:     for (LoaderConstraintEntry* probe = bucket(index);
duke@435:                                 probe != NULL;
duke@435:                                 probe = probe->next()) {
duke@435:       f->do_oop((oop*)(probe->name_addr()));
duke@435:       if (probe->klass() != NULL) {
duke@435:         f->do_oop((oop*)probe->klass_addr());
duke@435:       }
duke@435:       for (int n = 0; n < probe->num_loaders(); n++) {
duke@435:         if (probe->loader(n) != NULL) {
duke@435:           f->do_oop(probe->loader_addr(n));
duke@435:         }
duke@435:       }
duke@435:     }
duke@435:   }
duke@435: }
duke@435: 
duke@435: // We must keep the symbolOop used in the name alive.  We'll use the
duke@435: // loaders to decide if a particular entry can be purged.
duke@435: void LoaderConstraintTable::always_strong_classes_do(OopClosure* blk) {
duke@435:   // We must keep the symbolOop used in the name alive.
duke@435:   for (int cindex = 0; cindex < table_size(); cindex++) {
duke@435:     for (LoaderConstraintEntry* lc_probe = bucket(cindex);
duke@435:                                 lc_probe != NULL;
duke@435:                                 lc_probe = lc_probe->next()) {
duke@435:       assert (lc_probe->name() != NULL,  "corrupted loader constraint table");
duke@435:       blk->do_oop((oop*)lc_probe->name_addr());
duke@435:     }
duke@435:   }
duke@435: }
duke@435: 
duke@435: 
duke@435: // The loaderConstraintTable must always be accessed with the
duke@435: // SystemDictionary lock held. This is true even for readers as
duke@435: // entries in the table could be being dynamically resized.
duke@435: 
duke@435: LoaderConstraintEntry** LoaderConstraintTable::find_loader_constraint(
duke@435:                                     symbolHandle name, Handle loader) {
duke@435: 
duke@435:   unsigned int hash = compute_hash(name);
duke@435:   int index = hash_to_index(hash);
duke@435:   LoaderConstraintEntry** pp = bucket_addr(index);
duke@435:   while (*pp) {
duke@435:     LoaderConstraintEntry* p = *pp;
duke@435:     if (p->hash() == hash) {
duke@435:       if (p->name() == name()) {
duke@435:         for (int i = p->num_loaders() - 1; i >= 0; i--) {
duke@435:           if (p->loader(i) == loader()) {
duke@435:             return pp;
duke@435:           }
duke@435:         }
duke@435:       }
duke@435:     }
duke@435:     pp = p->next_addr();
duke@435:   }
duke@435:   return pp;
duke@435: }
duke@435: 
duke@435: 
duke@435: void LoaderConstraintTable::purge_loader_constraints(BoolObjectClosure* is_alive) {
jcoomes@1844:   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
duke@435:   // Remove unloaded entries from constraint table
duke@435:   for (int index = 0; index < table_size(); index++) {
duke@435:     LoaderConstraintEntry** p = bucket_addr(index);
duke@435:     while(*p) {
duke@435:       LoaderConstraintEntry* probe = *p;
duke@435:       klassOop klass = probe->klass();
duke@435:       // Remove klass that is no longer alive
duke@435:       if (klass != NULL && !is_alive->do_object_b(klass)) {
duke@435:         probe->set_klass(NULL);
duke@435:         if (TraceLoaderConstraints) {
duke@435:           ResourceMark rm;
duke@435:           tty->print_cr("[Purging class object from constraint for name %s,"
duke@435:                      " loader list:",
duke@435:                      probe->name()->as_C_string());
duke@435:           for (int i = 0; i < probe->num_loaders(); i++) {
duke@435:             tty->print_cr("[   [%d]: %s", i,
duke@435:                           SystemDictionary::loader_name(probe->loader(i)));
duke@435:           }
duke@435:         }
duke@435:       }
duke@435:       // Remove entries no longer alive from loader array
duke@435:       int n = 0;
duke@435:       while (n < probe->num_loaders()) {
duke@435:         if (probe->loader(n) != NULL) {
duke@435:           if (!is_alive->do_object_b(probe->loader(n))) {
duke@435:             if (TraceLoaderConstraints) {
duke@435:               ResourceMark rm;
duke@435:               tty->print_cr("[Purging loader %s from constraint for name %s",
duke@435:                             SystemDictionary::loader_name(probe->loader(n)),
duke@435:                             probe->name()->as_C_string()
duke@435:                             );
duke@435:             }
duke@435: 
duke@435:             // Compact array
duke@435:             int num = probe->num_loaders() - 1;
duke@435:             probe->set_num_loaders(num);
duke@435:             probe->set_loader(n, probe->loader(num));
duke@435:             probe->set_loader(num, NULL);
duke@435: 
duke@435:             if (TraceLoaderConstraints) {
duke@435:               ResourceMark rm;
duke@435:               tty->print_cr("[New loader list:");
duke@435:               for (int i = 0; i < probe->num_loaders(); i++) {
duke@435:                 tty->print_cr("[   [%d]: %s", i,
duke@435:                               SystemDictionary::loader_name(probe->loader(i)));
duke@435:               }
duke@435:             }
duke@435: 
duke@435:             continue;  // current element replaced, so restart without
duke@435:                        // incrementing n
duke@435:           }
duke@435:         }
duke@435:         n++;
duke@435:       }
duke@435:       // Check whether entry should be purged
duke@435:       if (probe->num_loaders() < 2) {
duke@435:             if (TraceLoaderConstraints) {
duke@435:               ResourceMark rm;
duke@435:               tty->print("[Purging complete constraint for name %s\n",
duke@435:                          probe->name()->as_C_string());
duke@435:             }
duke@435: 
duke@435:         // Purge entry
duke@435:         *p = probe->next();
duke@435:         FREE_C_HEAP_ARRAY(oop, probe->loaders());
duke@435:         free_entry(probe);
duke@435:       } else {
duke@435: #ifdef ASSERT
duke@435:         assert(is_alive->do_object_b(probe->name()), "name should be live");
duke@435:         if (probe->klass() != NULL) {
duke@435:           assert(is_alive->do_object_b(probe->klass()), "klass should be live");
duke@435:         }
duke@435:         for (n = 0; n < probe->num_loaders(); n++) {
duke@435:           if (probe->loader(n) != NULL) {
duke@435:             assert(is_alive->do_object_b(probe->loader(n)), "loader should be live");
duke@435:           }
duke@435:         }
duke@435: #endif
duke@435:         // Go to next entry
duke@435:         p = probe->next_addr();
duke@435:       }
duke@435:     }
duke@435:   }
duke@435: }
duke@435: 
duke@435: bool LoaderConstraintTable::add_entry(symbolHandle class_name,
duke@435:                                       klassOop klass1, Handle class_loader1,
duke@435:                                       klassOop klass2, Handle class_loader2) {
duke@435:   int failure_code = 0; // encode different reasons for failing
duke@435: 
duke@435:   if (klass1 != NULL && klass2 != NULL && klass1 != klass2) {
duke@435:     failure_code = 1;
duke@435:   } else {
duke@435:     klassOop klass = klass1 != NULL ? klass1 : klass2;
duke@435: 
duke@435:     LoaderConstraintEntry** pp1 = find_loader_constraint(class_name,
duke@435:                                                          class_loader1);
duke@435:     if (*pp1 != NULL && (*pp1)->klass() != NULL) {
duke@435:       if (klass != NULL) {
duke@435:         if (klass != (*pp1)->klass()) {
duke@435:           failure_code = 2;
duke@435:         }
duke@435:       } else {
duke@435:         klass = (*pp1)->klass();
duke@435:       }
duke@435:     }
duke@435: 
duke@435:     LoaderConstraintEntry** pp2 = find_loader_constraint(class_name,
duke@435:                                                          class_loader2);
duke@435:     if (*pp2 != NULL && (*pp2)->klass() != NULL) {
duke@435:       if (klass != NULL) {
duke@435:         if (klass != (*pp2)->klass()) {
duke@435:           failure_code = 3;
duke@435:         }
duke@435:       } else {
duke@435:         klass = (*pp2)->klass();
duke@435:       }
duke@435:     }
duke@435: 
duke@435:     if (failure_code == 0) {
duke@435:       if (*pp1 == NULL && *pp2 == NULL) {
duke@435:         unsigned int hash = compute_hash(class_name);
duke@435:         int index = hash_to_index(hash);
duke@435:         LoaderConstraintEntry* p;
duke@435:         p = new_entry(hash, class_name(), klass, 2, 2);
duke@435:         p->set_loaders(NEW_C_HEAP_ARRAY(oop, 2));
duke@435:         p->set_loader(0, class_loader1());
duke@435:         p->set_loader(1, class_loader2());
duke@435:         p->set_klass(klass);
duke@435:         p->set_next(bucket(index));
duke@435:         set_entry(index, p);
duke@435:         if (TraceLoaderConstraints) {
duke@435:           ResourceMark rm;
duke@435:           tty->print("[Adding new constraint for name: %s, loader[0]: %s,"
duke@435:                      " loader[1]: %s ]\n",
duke@435:                      class_name()->as_C_string(),
duke@435:                      SystemDictionary::loader_name(class_loader1()),
duke@435:                      SystemDictionary::loader_name(class_loader2())
duke@435:                      );
duke@435:         }
duke@435:       } else if (*pp1 == *pp2) {
duke@435:         /* constraint already imposed */
duke@435:         if ((*pp1)->klass() == NULL) {
duke@435:           (*pp1)->set_klass(klass);
duke@435:           if (TraceLoaderConstraints) {
duke@435:             ResourceMark rm;
duke@435:             tty->print("[Setting class object in existing constraint for"
duke@435:                        " name: %s and loader %s ]\n",
duke@435:                        class_name()->as_C_string(),
duke@435:                        SystemDictionary::loader_name(class_loader1())
duke@435:                        );
duke@435:           }
duke@435:         } else {
duke@435:           assert((*pp1)->klass() == klass, "loader constraints corrupted");
duke@435:         }
duke@435:       } else if (*pp1 == NULL) {
duke@435:         extend_loader_constraint(*pp2, class_loader1, klass);
duke@435:       } else if (*pp2 == NULL) {
duke@435:         extend_loader_constraint(*pp1, class_loader2, klass);
duke@435:       } else {
duke@435:         merge_loader_constraints(pp1, pp2, klass);
duke@435:       }
duke@435:     }
duke@435:   }
duke@435: 
duke@435:   if (failure_code != 0 && TraceLoaderConstraints) {
duke@435:     ResourceMark rm;
duke@435:     const char* reason = "";
duke@435:     switch(failure_code) {
duke@435:     case 1: reason = "the class objects presented by loader[0] and loader[1]"
duke@435:               " are different"; break;
duke@435:     case 2: reason = "the class object presented by loader[0] does not match"
duke@435:               " the stored class object in the constraint"; break;
duke@435:     case 3: reason = "the class object presented by loader[1] does not match"
duke@435:               " the stored class object in the constraint"; break;
duke@435:     default: reason = "unknown reason code";
duke@435:     }
duke@435:     tty->print("[Failed to add constraint for name: %s, loader[0]: %s,"
duke@435:                " loader[1]: %s, Reason: %s ]\n",
duke@435:                class_name()->as_C_string(),
duke@435:                SystemDictionary::loader_name(class_loader1()),
duke@435:                SystemDictionary::loader_name(class_loader2()),
duke@435:                reason
duke@435:                );
duke@435:   }
duke@435: 
duke@435:   return failure_code == 0;
duke@435: }
duke@435: 
duke@435: 
duke@435: // return true if the constraint was updated, false if the constraint is
duke@435: // violated
duke@435: bool LoaderConstraintTable::check_or_update(instanceKlassHandle k,
duke@435:                                                    Handle loader,
duke@435:                                                    symbolHandle name) {
duke@435:   LoaderConstraintEntry* p = *(find_loader_constraint(name, loader));
duke@435:   if (p && p->klass() != NULL && p->klass() != k()) {
duke@435:     if (TraceLoaderConstraints) {
duke@435:       ResourceMark rm;
duke@435:       tty->print("[Constraint check failed for name %s, loader %s: "
duke@435:                  "the presented class object differs from that stored ]\n",
duke@435:                  name()->as_C_string(),
duke@435:                  SystemDictionary::loader_name(loader()));
duke@435:     }
duke@435:     return false;
duke@435:   } else {
duke@435:     if (p && p->klass() == NULL) {
duke@435:       p->set_klass(k());
duke@435:       if (TraceLoaderConstraints) {
duke@435:         ResourceMark rm;
duke@435:         tty->print("[Updating constraint for name %s, loader %s, "
duke@435:                    "by setting class object ]\n",
duke@435:                    name()->as_C_string(),
duke@435:                    SystemDictionary::loader_name(loader()));
duke@435:       }
duke@435:     }
duke@435:     return true;
duke@435:   }
duke@435: }
duke@435: 
duke@435: klassOop LoaderConstraintTable::find_constrained_klass(symbolHandle name,
duke@435:                                                        Handle loader) {
duke@435:   LoaderConstraintEntry *p = *(find_loader_constraint(name, loader));
duke@435:   if (p != NULL && p->klass() != NULL)
duke@435:     return p->klass();
duke@435: 
duke@435:   // No constraints, or else no klass loaded yet.
duke@435:   return NULL;
duke@435: }
duke@435: 
duke@435: void LoaderConstraintTable::ensure_loader_constraint_capacity(
duke@435:                                                      LoaderConstraintEntry *p,
duke@435:                                                     int nfree) {
duke@435:     if (p->max_loaders() - p->num_loaders() < nfree) {
duke@435:         int n = nfree + p->num_loaders();
duke@435:         oop* new_loaders = NEW_C_HEAP_ARRAY(oop, n);
duke@435:         memcpy(new_loaders, p->loaders(), sizeof(oop) * p->num_loaders());
duke@435:         p->set_max_loaders(n);
duke@435:         FREE_C_HEAP_ARRAY(oop, p->loaders());
duke@435:         p->set_loaders(new_loaders);
duke@435:     }
duke@435: }
duke@435: 
duke@435: 
duke@435: void LoaderConstraintTable::extend_loader_constraint(LoaderConstraintEntry* p,
duke@435:                                                      Handle loader,
duke@435:                                                      klassOop klass) {
duke@435:   ensure_loader_constraint_capacity(p, 1);
duke@435:   int num = p->num_loaders();
duke@435:   p->set_loader(num, loader());
duke@435:   p->set_num_loaders(num + 1);
duke@435:   if (TraceLoaderConstraints) {
duke@435:     ResourceMark rm;
duke@435:     tty->print("[Extending constraint for name %s by adding loader[%d]: %s %s",
duke@435:                p->name()->as_C_string(),
duke@435:                num,
duke@435:                SystemDictionary::loader_name(loader()),
duke@435:                (p->klass() == NULL ? " and setting class object ]\n" : " ]\n")
duke@435:                );
duke@435:   }
duke@435:   if (p->klass() == NULL) {
duke@435:     p->set_klass(klass);
duke@435:   } else {
duke@435:     assert(klass == NULL || p->klass() == klass, "constraints corrupted");
duke@435:   }
duke@435: }
duke@435: 
duke@435: 
duke@435: void LoaderConstraintTable::merge_loader_constraints(
duke@435:                                                    LoaderConstraintEntry** pp1,
duke@435:                                                    LoaderConstraintEntry** pp2,
duke@435:                                                    klassOop klass) {
duke@435:   // make sure *pp1 has higher capacity
duke@435:   if ((*pp1)->max_loaders() < (*pp2)->max_loaders()) {
duke@435:     LoaderConstraintEntry** tmp = pp2;
duke@435:     pp2 = pp1;
duke@435:     pp1 = tmp;
duke@435:   }
duke@435: 
duke@435:   LoaderConstraintEntry* p1 = *pp1;
duke@435:   LoaderConstraintEntry* p2 = *pp2;
duke@435: 
duke@435:   ensure_loader_constraint_capacity(p1, p2->num_loaders());
duke@435: 
duke@435:   for (int i = 0; i < p2->num_loaders(); i++) {
duke@435:     int num = p1->num_loaders();
duke@435:     p1->set_loader(num, p2->loader(i));
duke@435:     p1->set_num_loaders(num + 1);
duke@435:   }
duke@435: 
duke@435:   if (TraceLoaderConstraints) {
duke@435:     ResourceMark rm;
duke@435:     tty->print_cr("[Merged constraints for name %s, new loader list:",
duke@435:                   p1->name()->as_C_string()
duke@435:                   );
duke@435: 
duke@435:     for (int i = 0; i < p1->num_loaders(); i++) {
duke@435:       tty->print_cr("[   [%d]: %s", i,
duke@435:                     SystemDictionary::loader_name(p1->loader(i)));
duke@435:     }
duke@435:     if (p1->klass() == NULL) {
duke@435:       tty->print_cr("[... and setting class object]");
duke@435:     }
duke@435:   }
duke@435: 
duke@435:   // p1->klass() will hold NULL if klass, p2->klass(), and old
duke@435:   // p1->klass() are all NULL.  In addition, all three must have
duke@435:   // matching non-NULL values, otherwise either the constraints would
duke@435:   // have been violated, or the constraints had been corrupted (and an
duke@435:   // assertion would fail).
duke@435:   if (p2->klass() != NULL) {
duke@435:     assert(p2->klass() == klass, "constraints corrupted");
duke@435:   }
duke@435:   if (p1->klass() == NULL) {
duke@435:     p1->set_klass(klass);
duke@435:   } else {
duke@435:     assert(p1->klass() == klass, "constraints corrupted");
duke@435:   }
duke@435: 
duke@435:   *pp2 = p2->next();
duke@435:   FREE_C_HEAP_ARRAY(oop, p2->loaders());
duke@435:   free_entry(p2);
duke@435:   return;
duke@435: }
duke@435: 
duke@435: 
tonyp@1693: void LoaderConstraintTable::verify(Dictionary* dictionary,
tonyp@1693:                                    PlaceholderTable* placeholders) {
duke@435:   Thread *thread = Thread::current();
duke@435:   for (int cindex = 0; cindex < _loader_constraint_size; cindex++) {
duke@435:     for (LoaderConstraintEntry* probe = bucket(cindex);
duke@435:                                 probe != NULL;
duke@435:                                 probe = probe->next()) {
duke@435:       guarantee(probe->name()->is_symbol(), "should be symbol");
duke@435:       if (probe->klass() != NULL) {
duke@435:         instanceKlass* ik = instanceKlass::cast(probe->klass());
duke@435:         guarantee(ik->name() == probe->name(), "name should match");
duke@435:         symbolHandle name (thread, ik->name());
duke@435:         Handle loader(thread, ik->class_loader());
duke@435:         unsigned int d_hash = dictionary->compute_hash(name, loader);
duke@435:         int d_index = dictionary->hash_to_index(d_hash);
duke@435:         klassOop k = dictionary->find_class(d_index, d_hash, name, loader);
tonyp@1693:         if (k != NULL) {
tonyp@1693:           // We found the class in the system dictionary, so we should
tonyp@1693:           // make sure that the klassOop matches what we already have.
tonyp@1693:           guarantee(k == probe->klass(), "klass should be in dictionary");
tonyp@1693:         } else {
tonyp@1693:           // If we don't find the class in the system dictionary, it
tonyp@1693:           // has to be in the placeholders table.
tonyp@1693:           unsigned int p_hash = placeholders->compute_hash(name, loader);
tonyp@1693:           int p_index = placeholders->hash_to_index(p_hash);
tonyp@1693:           PlaceholderEntry* entry = placeholders->get_entry(p_index, p_hash,
tonyp@1693:                                                             name, loader);
tonyp@1693: 
tonyp@1693:           // The instanceKlass might not be on the entry, so the only
tonyp@1693:           // thing we can check here is whether we were successful in
tonyp@1693:           // finding the class in the placeholders table.
tonyp@1693:           guarantee(entry != NULL, "klass should be in the placeholders");
tonyp@1693:         }
duke@435:       }
duke@435:       for (int n = 0; n< probe->num_loaders(); n++) {
duke@435:         guarantee(probe->loader(n)->is_oop_or_null(), "should be oop");
duke@435:       }
duke@435:     }
duke@435:   }
duke@435: }
duke@435: 
duke@435: #ifndef PRODUCT
duke@435: 
duke@435: // Called with the system dictionary lock held
duke@435: void LoaderConstraintTable::print() {
duke@435:   ResourceMark rm;
duke@435: 
duke@435:   assert_locked_or_safepoint(SystemDictionary_lock);
duke@435:   tty->print_cr("Java loader constraints (entries=%d)", _loader_constraint_size);
duke@435:   for (int cindex = 0; cindex < _loader_constraint_size; cindex++) {
duke@435:     for (LoaderConstraintEntry* probe = bucket(cindex);
duke@435:                                 probe != NULL;
duke@435:                                 probe = probe->next()) {
duke@435:       tty->print("%4d: ", cindex);
duke@435:       probe->name()->print();
duke@435:       tty->print(" , loaders:");
duke@435:       for (int n = 0; n < probe->num_loaders(); n++) {
duke@435:         probe->loader(n)->print_value();
duke@435:         tty->print(", ");
duke@435:       }
duke@435:       tty->cr();
duke@435:     }
duke@435:   }
duke@435: }
duke@435: #endif