--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/classfile/loaderConstraints.cpp Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,507 @@
+/*
+ * 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;
+}
+
+
+klassOop LoaderConstraintTable::find_constrained_elem_klass(symbolHandle name,
+ symbolHandle elem_name,
+ Handle loader,
+ TRAPS) {
+ LoaderConstraintEntry *p = *(find_loader_constraint(name, loader));
+ if (p != NULL) {
+ assert(p->klass() == NULL, "Expecting null array klass");
+
+ // The array name has a constraint, but it will not have a class. Check
+ // each loader for an associated elem
+ for (int i = 0; i < p->num_loaders(); i++) {
+ Handle no_protection_domain;
+
+ klassOop k = SystemDictionary::find(elem_name, p->loader(i), no_protection_domain, THREAD);
+ if (k != NULL) {
+ // Return the first elem klass found.
+ return k;
+ }
+ }
+ }
+
+ // 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