| /* |
| * Copyright (c) 2016, 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/classLoaderData.hpp" |
| #include "classfile/javaClasses.hpp" |
| #include "classfile/moduleEntry.hpp" |
| #include "logging/log.hpp" |
| #include "memory/resourceArea.hpp" |
| #include "oops/symbol.hpp" |
| #include "prims/jni.h" |
| #include "runtime/handles.inline.hpp" |
| #include "runtime/safepoint.hpp" |
| #include "trace/traceMacros.hpp" |
| #include "utilities/events.hpp" |
| #include "utilities/growableArray.hpp" |
| #include "utilities/hashtable.inline.hpp" |
| #include "utilities/ostream.hpp" |
| |
| ModuleEntry* ModuleEntryTable::_javabase_module = NULL; |
| |
| void ModuleEntry::set_location(Symbol* location) { |
| if (_location != NULL) { |
| // _location symbol's refcounts are managed by ModuleEntry, |
| // must decrement the old one before updating. |
| _location->decrement_refcount(); |
| } |
| |
| _location = location; |
| |
| if (location != NULL) { |
| location->increment_refcount(); |
| } |
| } |
| |
| bool ModuleEntry::is_non_jdk_module() { |
| ResourceMark rm; |
| if (location() != NULL) { |
| const char* loc = location()->as_C_string(); |
| if (strncmp(loc, "jrt:/java.", 10) != 0 && strncmp(loc, "jrt:/jdk.", 9) != 0) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| void ModuleEntry::set_version(Symbol* version) { |
| if (_version != NULL) { |
| // _version symbol's refcounts are managed by ModuleEntry, |
| // must decrement the old one before updating. |
| _version->decrement_refcount(); |
| } |
| |
| _version = version; |
| |
| if (version != NULL) { |
| version->increment_refcount(); |
| } |
| } |
| |
| // Returns the shared ProtectionDomain |
| oop ModuleEntry::shared_protection_domain() { |
| return _pd.resolve(); |
| } |
| |
| // Set the shared ProtectionDomain atomically |
| void ModuleEntry::set_shared_protection_domain(ClassLoaderData *loader_data, |
| Handle pd_h) { |
| // Create a handle for the shared ProtectionDomain and save it atomically. |
| // init_handle_locked checks if someone beats us setting the _pd cache. |
| loader_data->init_handle_locked(_pd, pd_h); |
| } |
| |
| // Returns true if this module can read module m |
| bool ModuleEntry::can_read(ModuleEntry* m) const { |
| assert(m != NULL, "No module to lookup in this module's reads list"); |
| |
| // Unnamed modules read everyone and all modules |
| // read java.base. If either of these conditions |
| // hold, readability has been established. |
| if (!this->is_named() || |
| (m == ModuleEntryTable::javabase_moduleEntry())) { |
| return true; |
| } |
| |
| MutexLocker m1(Module_lock); |
| // This is a guard against possible race between agent threads that redefine |
| // or retransform classes in this module. Only one of them is adding the |
| // default read edges to the unnamed modules of the boot and app class loaders |
| // with an upcall to jdk.internal.module.Modules.transformedByAgent. |
| // At the same time, another thread can instrument the module classes by |
| // injecting dependencies that require the default read edges for resolution. |
| if (this->has_default_read_edges() && !m->is_named()) { |
| ClassLoaderData* cld = m->loader_data(); |
| if (cld->is_the_null_class_loader_data() || cld->is_system_class_loader_data()) { |
| return true; // default read edge |
| } |
| } |
| if (!has_reads_list()) { |
| return false; |
| } else { |
| return _reads->contains(m); |
| } |
| } |
| |
| // Add a new module to this module's reads list |
| void ModuleEntry::add_read(ModuleEntry* m) { |
| // Unnamed module is special cased and can read all modules |
| if (!is_named()) { |
| return; |
| } |
| |
| MutexLocker m1(Module_lock); |
| if (m == NULL) { |
| set_can_read_all_unnamed(); |
| } else { |
| if (_reads == NULL) { |
| // Lazily create a module's reads list |
| _reads = new (ResourceObj::C_HEAP, mtModule)GrowableArray<ModuleEntry*>(MODULE_READS_SIZE, true); |
| } |
| |
| // Determine, based on this newly established read edge to module m, |
| // if this module's read list should be walked at a GC safepoint. |
| set_read_walk_required(m->loader_data()); |
| |
| // Establish readability to module m |
| _reads->append_if_missing(m); |
| } |
| } |
| |
| // If the module's loader, that a read edge is being established to, is |
| // not the same loader as this module's and is not one of the 3 builtin |
| // class loaders, then this module's reads list must be walked at GC |
| // safepoint. Modules have the same life cycle as their defining class |
| // loaders and should be removed if dead. |
| void ModuleEntry::set_read_walk_required(ClassLoaderData* m_loader_data) { |
| assert(is_named(), "Cannot call set_read_walk_required on unnamed module"); |
| assert_locked_or_safepoint(Module_lock); |
| if (!_must_walk_reads && |
| loader_data() != m_loader_data && |
| !m_loader_data->is_builtin_class_loader_data()) { |
| _must_walk_reads = true; |
| if (log_is_enabled(Trace, module)) { |
| ResourceMark rm; |
| log_trace(module)("ModuleEntry::set_read_walk_required(): module %s reads list must be walked", |
| (name() != NULL) ? name()->as_C_string() : UNNAMED_MODULE); |
| } |
| } |
| } |
| |
| // Set whether the module is open, i.e. all its packages are unqualifiedly exported |
| void ModuleEntry::set_is_open(bool is_open) { |
| assert_lock_strong(Module_lock); |
| _is_open = is_open; |
| } |
| |
| // Returns true if the module has a non-empty reads list. As such, the unnamed |
| // module will return false. |
| bool ModuleEntry::has_reads_list() const { |
| assert_locked_or_safepoint(Module_lock); |
| return ((_reads != NULL) && !_reads->is_empty()); |
| } |
| |
| // Purge dead module entries out of reads list. |
| void ModuleEntry::purge_reads() { |
| assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); |
| |
| if (_must_walk_reads && has_reads_list()) { |
| // This module's _must_walk_reads flag will be reset based |
| // on the remaining live modules on the reads list. |
| _must_walk_reads = false; |
| |
| if (log_is_enabled(Trace, module)) { |
| ResourceMark rm; |
| log_trace(module)("ModuleEntry::purge_reads(): module %s reads list being walked", |
| (name() != NULL) ? name()->as_C_string() : UNNAMED_MODULE); |
| } |
| |
| // Go backwards because this removes entries that are dead. |
| int len = _reads->length(); |
| for (int idx = len - 1; idx >= 0; idx--) { |
| ModuleEntry* module_idx = _reads->at(idx); |
| ClassLoaderData* cld_idx = module_idx->loader_data(); |
| if (cld_idx->is_unloading()) { |
| _reads->delete_at(idx); |
| } else { |
| // Update the need to walk this module's reads based on live modules |
| set_read_walk_required(cld_idx); |
| } |
| } |
| } |
| } |
| |
| void ModuleEntry::module_reads_do(ModuleClosure* const f) { |
| assert_locked_or_safepoint(Module_lock); |
| assert(f != NULL, "invariant"); |
| |
| if (has_reads_list()) { |
| int reads_len = _reads->length(); |
| for (int i = 0; i < reads_len; ++i) { |
| f->do_module(_reads->at(i)); |
| } |
| } |
| } |
| |
| void ModuleEntry::delete_reads() { |
| assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); |
| delete _reads; |
| _reads = NULL; |
| } |
| |
| ModuleEntry* ModuleEntry::create_unnamed_module(ClassLoaderData* cld) { |
| // The java.lang.Module for this loader's |
| // corresponding unnamed module can be found in the java.lang.ClassLoader object. |
| oop module = java_lang_ClassLoader::unnamedModule(cld->class_loader()); |
| ModuleEntry* unnamed_module = new_unnamed_module_entry(Handle(Thread::current(), module), cld); |
| |
| // Store pointer to the ModuleEntry in the unnamed module's java.lang.Module |
| // object. |
| java_lang_Module::set_module_entry(module, unnamed_module); |
| |
| return unnamed_module; |
| } |
| |
| ModuleEntry* ModuleEntry::create_boot_unnamed_module(ClassLoaderData* cld) { |
| // For the boot loader, the java.lang.Module for the unnamed module |
| // is not known until a call to JVM_SetBootLoaderUnnamedModule is made. At |
| // this point initially create the ModuleEntry for the unnamed module. |
| ModuleEntry* unnamed_module = new_unnamed_module_entry(Handle(), cld); |
| assert(unnamed_module != NULL, "boot loader unnamed module should not be null"); |
| return unnamed_module; |
| } |
| |
| // When creating an unnamed module, this is called without holding the Module_lock. |
| // This is okay because the unnamed module gets created before the ClassLoaderData |
| // is available to other threads. |
| ModuleEntry* ModuleEntry::new_unnamed_module_entry(Handle module_handle, ClassLoaderData* cld) { |
| ModuleEntry* entry = (ModuleEntry*) NEW_C_HEAP_ARRAY(char, sizeof(ModuleEntry), mtModule); |
| |
| // Initialize everything BasicHashtable would |
| entry->set_next(NULL); |
| entry->set_hash(0); |
| entry->set_literal(NULL); |
| |
| // Initialize fields specific to a ModuleEntry |
| entry->init(); |
| |
| // Unnamed modules can read all other unnamed modules. |
| entry->set_can_read_all_unnamed(); |
| |
| if (!module_handle.is_null()) { |
| entry->set_module(cld->add_handle(module_handle)); |
| } |
| |
| entry->set_loader_data(cld); |
| entry->_is_open = true; |
| |
| TRACE_INIT_ID(entry); |
| |
| return entry; |
| } |
| |
| void ModuleEntry::delete_unnamed_module() { |
| // Do not need unlink_entry() since the unnamed module is not in the hashtable |
| FREE_C_HEAP_ARRAY(char, this); |
| } |
| |
| ModuleEntryTable::ModuleEntryTable(int table_size) |
| : Hashtable<Symbol*, mtModule>(table_size, sizeof(ModuleEntry)) |
| { |
| } |
| |
| ModuleEntryTable::~ModuleEntryTable() { |
| assert_locked_or_safepoint(Module_lock); |
| |
| // Walk through all buckets and all entries in each bucket, |
| // freeing each entry. |
| for (int i = 0; i < table_size(); ++i) { |
| for (ModuleEntry* m = bucket(i); m != NULL;) { |
| ModuleEntry* to_remove = m; |
| // read next before freeing. |
| m = m->next(); |
| |
| ResourceMark rm; |
| if (to_remove->name() != NULL) { |
| log_info(module, unload)("unloading module %s", to_remove->name()->as_C_string()); |
| } |
| log_debug(module)("ModuleEntryTable: deleting module: %s", to_remove->name() != NULL ? |
| to_remove->name()->as_C_string() : UNNAMED_MODULE); |
| |
| // Clean out the C heap allocated reads list first before freeing the entry |
| to_remove->delete_reads(); |
| if (to_remove->name() != NULL) { |
| to_remove->name()->decrement_refcount(); |
| } |
| if (to_remove->version() != NULL) { |
| to_remove->version()->decrement_refcount(); |
| } |
| if (to_remove->location() != NULL) { |
| to_remove->location()->decrement_refcount(); |
| } |
| |
| // Unlink from the Hashtable prior to freeing |
| unlink_entry(to_remove); |
| FREE_C_HEAP_ARRAY(char, to_remove); |
| } |
| } |
| assert(number_of_entries() == 0, "should have removed all entries"); |
| assert(new_entry_free_list() == NULL, "entry present on ModuleEntryTable's free list"); |
| free_buckets(); |
| } |
| |
| ModuleEntry* ModuleEntryTable::new_entry(unsigned int hash, Handle module_handle, |
| bool is_open, Symbol* name, |
| Symbol* version, Symbol* location, |
| ClassLoaderData* loader_data) { |
| assert(Module_lock->owned_by_self(), "should have the Module_lock"); |
| ModuleEntry* entry = (ModuleEntry*)Hashtable<Symbol*, mtModule>::allocate_new_entry(hash, name); |
| |
| // Initialize fields specific to a ModuleEntry |
| entry->init(); |
| if (name != NULL) { |
| name->increment_refcount(); |
| } else { |
| // Unnamed modules can read all other unnamed modules. |
| entry->set_can_read_all_unnamed(); |
| } |
| |
| if (!module_handle.is_null()) { |
| entry->set_module(loader_data->add_handle(module_handle)); |
| } |
| |
| entry->set_loader_data(loader_data); |
| entry->set_version(version); |
| entry->set_location(location); |
| entry->set_is_open(is_open); |
| |
| if (ClassLoader::is_in_patch_mod_entries(name)) { |
| entry->set_is_patched(); |
| if (log_is_enabled(Trace, module, patch)) { |
| ResourceMark rm; |
| log_trace(module, patch)("Marked module %s as patched from --patch-module", name->as_C_string()); |
| } |
| } |
| |
| TRACE_INIT_ID(entry); |
| |
| return entry; |
| } |
| |
| void ModuleEntryTable::add_entry(int index, ModuleEntry* new_entry) { |
| assert(Module_lock->owned_by_self(), "should have the Module_lock"); |
| Hashtable<Symbol*, mtModule>::add_entry(index, (HashtableEntry<Symbol*, mtModule>*)new_entry); |
| } |
| |
| ModuleEntry* ModuleEntryTable::locked_create_entry_or_null(Handle module_handle, |
| bool is_open, |
| Symbol* module_name, |
| Symbol* module_version, |
| Symbol* module_location, |
| ClassLoaderData* loader_data) { |
| assert(module_name != NULL, "ModuleEntryTable locked_create_entry_or_null should never be called for unnamed module."); |
| assert(Module_lock->owned_by_self(), "should have the Module_lock"); |
| // Check if module already exists. |
| if (lookup_only(module_name) != NULL) { |
| return NULL; |
| } else { |
| ModuleEntry* entry = new_entry(compute_hash(module_name), module_handle, is_open, module_name, |
| module_version, module_location, loader_data); |
| add_entry(index_for(module_name), entry); |
| return entry; |
| } |
| } |
| |
| // lookup_only by Symbol* to find a ModuleEntry. |
| ModuleEntry* ModuleEntryTable::lookup_only(Symbol* name) { |
| assert(name != NULL, "name cannot be NULL"); |
| int index = index_for(name); |
| for (ModuleEntry* m = bucket(index); m != NULL; m = m->next()) { |
| if (m->name()->fast_compare(name) == 0) { |
| return m; |
| } |
| } |
| return NULL; |
| } |
| |
| // Remove dead modules from all other alive modules' reads list. |
| // This should only occur at class unloading. |
| void ModuleEntryTable::purge_all_module_reads() { |
| assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); |
| for (int i = 0; i < table_size(); i++) { |
| for (ModuleEntry* entry = bucket(i); |
| entry != NULL; |
| entry = entry->next()) { |
| entry->purge_reads(); |
| } |
| } |
| } |
| |
| void ModuleEntryTable::finalize_javabase(Handle module_handle, Symbol* version, Symbol* location) { |
| assert(Module_lock->owned_by_self(), "should have the Module_lock"); |
| ClassLoaderData* boot_loader_data = ClassLoaderData::the_null_class_loader_data(); |
| ModuleEntryTable* module_table = boot_loader_data->modules(); |
| |
| assert(module_table != NULL, "boot loader's ModuleEntryTable not defined"); |
| |
| if (module_handle.is_null()) { |
| fatal("Unable to finalize module definition for " JAVA_BASE_NAME); |
| } |
| |
| // Set java.lang.Module, version and location for java.base |
| ModuleEntry* jb_module = javabase_moduleEntry(); |
| assert(jb_module != NULL, JAVA_BASE_NAME " ModuleEntry not defined"); |
| jb_module->set_version(version); |
| jb_module->set_location(location); |
| // Once java.base's ModuleEntry _module field is set with the known |
| // java.lang.Module, java.base is considered "defined" to the VM. |
| jb_module->set_module(boot_loader_data->add_handle(module_handle)); |
| |
| // Store pointer to the ModuleEntry for java.base in the java.lang.Module object. |
| java_lang_Module::set_module_entry(module_handle(), jb_module); |
| } |
| |
| // Within java.lang.Class instances there is a java.lang.Module field that must |
| // be set with the defining module. During startup, prior to java.base's definition, |
| // classes needing their module field set are added to the fixup_module_list. |
| // Their module field is set once java.base's java.lang.Module is known to the VM. |
| void ModuleEntryTable::patch_javabase_entries(Handle module_handle) { |
| if (module_handle.is_null()) { |
| fatal("Unable to patch the module field of classes loaded prior to " |
| JAVA_BASE_NAME "'s definition, invalid java.lang.Module"); |
| } |
| |
| // Do the fixups for the basic primitive types |
| java_lang_Class::set_module(Universe::int_mirror(), module_handle()); |
| java_lang_Class::set_module(Universe::float_mirror(), module_handle()); |
| java_lang_Class::set_module(Universe::double_mirror(), module_handle()); |
| java_lang_Class::set_module(Universe::byte_mirror(), module_handle()); |
| java_lang_Class::set_module(Universe::bool_mirror(), module_handle()); |
| java_lang_Class::set_module(Universe::char_mirror(), module_handle()); |
| java_lang_Class::set_module(Universe::long_mirror(), module_handle()); |
| java_lang_Class::set_module(Universe::short_mirror(), module_handle()); |
| java_lang_Class::set_module(Universe::void_mirror(), module_handle()); |
| |
| // Do the fixups for classes that have already been created. |
| GrowableArray <Klass*>* list = java_lang_Class::fixup_module_field_list(); |
| int list_length = list->length(); |
| for (int i = 0; i < list_length; i++) { |
| Klass* k = list->at(i); |
| assert(k->is_klass(), "List should only hold classes"); |
| java_lang_Class::fixup_module_field(k, module_handle); |
| k->class_loader_data()->dec_keep_alive(); |
| } |
| |
| delete java_lang_Class::fixup_module_field_list(); |
| java_lang_Class::set_fixup_module_field_list(NULL); |
| } |
| |
| void ModuleEntryTable::print(outputStream* st) { |
| st->print_cr("Module Entry Table (table_size=%d, entries=%d)", |
| table_size(), number_of_entries()); |
| for (int i = 0; i < table_size(); i++) { |
| for (ModuleEntry* probe = bucket(i); |
| probe != NULL; |
| probe = probe->next()) { |
| probe->print(st); |
| } |
| } |
| } |
| |
| void ModuleEntry::print(outputStream* st) { |
| ResourceMark rm; |
| st->print_cr("entry " PTR_FORMAT " name %s module " PTR_FORMAT " loader %s version %s location %s strict %s next " PTR_FORMAT, |
| p2i(this), |
| name() == NULL ? UNNAMED_MODULE : name()->as_C_string(), |
| p2i(module()), |
| loader_data()->loader_name(), |
| version() != NULL ? version()->as_C_string() : "NULL", |
| location() != NULL ? location()->as_C_string() : "NULL", |
| BOOL_TO_STR(!can_read_all_unnamed()), p2i(next())); |
| } |
| |
| void ModuleEntryTable::verify() { |
| verify_table<ModuleEntry>("Module Entry Table"); |
| } |
| |
| void ModuleEntry::verify() { |
| guarantee(loader_data() != NULL, "A module entry must be associated with a loader."); |
| } |