1 /* 2 * Copyright (c) 2016, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_VM_CLASSFILE_MODULEENTRY_HPP 26 #define SHARE_VM_CLASSFILE_MODULEENTRY_HPP 27 28 #include "classfile/classLoaderData.hpp" 29 #include "classfile/vmSymbols.hpp" 30 #include "oops/oopHandle.hpp" 31 #include "oops/symbol.hpp" 32 #include "prims/jni.h" 33 #include "runtime/jniHandles.hpp" 34 #include "runtime/mutexLocker.hpp" 35 #include "trace/traceMacros.hpp" 36 #include "utilities/growableArray.hpp" 37 #include "utilities/hashtable.hpp" 38 #include "utilities/ostream.hpp" 39 40 #define UNNAMED_MODULE "Unnamed Module" 41 #define JAVAPKG "java" 42 #define JAVAPKG_LEN 4 43 #define JAVA_BASE_NAME "java.base" 44 45 class ModuleClosure; 46 47 // A ModuleEntry describes a module that has been defined by a call to JVM_DefineModule. 48 // It contains: 49 // - Symbol* containing the module's name. 50 // - pointer to the java.lang.Module for this module. 51 // - pointer to the java.security.ProtectionDomain shared by classes defined to this module. 52 // - ClassLoaderData*, class loader of this module. 53 // - a growable array containg other module entries that this module can read. 54 // - a flag indicating if this module can read all unnamed modules. 55 // 56 // The Mutex Module_lock is shared between ModuleEntry and PackageEntry, to lock either 57 // data structure. 58 class ModuleEntry : public HashtableEntry<Symbol*, mtModule> { 59 private: 60 OopHandle _module; // java.lang.Module 61 OopHandle _pd; // java.security.ProtectionDomain, cached 62 // for shared classes from this module 63 ClassLoaderData* _loader_data; 64 GrowableArray<ModuleEntry*>* _reads; // list of modules that are readable by this module 65 Symbol* _version; // module version number 66 Symbol* _location; // module location 67 bool _can_read_all_unnamed; 68 bool _has_default_read_edges; // JVMTI redefine/retransform support 69 bool _must_walk_reads; // walk module's reads list at GC safepoints to purge out dead modules 70 bool _is_open; // whether the packages in the module are all unqualifiedly exported 71 bool _is_patched; // whether the module is patched via --patch-module 72 TRACE_DEFINE_TRACE_ID_FIELD; 73 enum {MODULE_READS_SIZE = 101}; // Initial size of list of modules that the module can read. 74 75 public: 76 void init() { 77 _module = NULL; 78 _loader_data = NULL; 79 _pd = NULL; 80 _reads = NULL; 81 _version = NULL; 82 _location = NULL; 83 _can_read_all_unnamed = false; 84 _has_default_read_edges = false; 85 _must_walk_reads = false; 86 _is_patched = false; 87 _is_open = false; 88 } 89 90 Symbol* name() const { return literal(); } 91 void set_name(Symbol* n) { set_literal(n); } 92 93 oop module() const { return _module.resolve(); } 94 OopHandle module_handle() const { return _module; } 95 void set_module(OopHandle j) { _module = j; } 96 97 // The shared ProtectionDomain reference is set once the VM loads a shared class 98 // originated from the current Module. The referenced ProtectionDomain object is 99 // created by the ClassLoader when loading a class (shared or non-shared) from the 100 // Module for the first time. This ProtectionDomain object is used for all 101 // classes from the Module loaded by the same ClassLoader. 102 oop shared_protection_domain(); 103 void set_shared_protection_domain(ClassLoaderData *loader_data, Handle pd); 104 105 ClassLoaderData* loader_data() const { return _loader_data; } 106 void set_loader_data(ClassLoaderData* l) { _loader_data = l; } 107 108 Symbol* version() const { return _version; } 109 void set_version(Symbol* version); 110 111 Symbol* location() const { return _location; } 112 void set_location(Symbol* location); 113 bool is_non_jdk_module(); 114 115 bool can_read(ModuleEntry* m) const; 116 bool has_reads_list() const; 117 void add_read(ModuleEntry* m); 118 void set_read_walk_required(ClassLoaderData* m_loader_data); 119 120 bool is_open() const { return _is_open; } 121 void set_is_open(bool is_open); 122 123 bool is_named() const { return (name() != NULL); } 124 125 bool can_read_all_unnamed() const { 126 assert(is_named() || _can_read_all_unnamed == true, 127 "unnamed modules can always read all unnamed modules"); 128 return _can_read_all_unnamed; 129 } 130 131 // Modules can only go from strict to loose. 132 void set_can_read_all_unnamed() { _can_read_all_unnamed = true; } 133 134 bool has_default_read_edges() const { 135 return _has_default_read_edges; 136 } 137 138 // Sets true and returns the previous value. 139 bool set_has_default_read_edges() { 140 MutexLocker ml(Module_lock); 141 bool prev = _has_default_read_edges; 142 _has_default_read_edges = true; 143 return prev; 144 } 145 146 void set_is_patched() { 147 _is_patched = true; 148 } 149 bool is_patched() { 150 return _is_patched; 151 } 152 153 ModuleEntry* next() const { 154 return (ModuleEntry*)HashtableEntry<Symbol*, mtModule>::next(); 155 } 156 ModuleEntry** next_addr() { 157 return (ModuleEntry**)HashtableEntry<Symbol*, mtModule>::next_addr(); 158 } 159 160 // iteration support for readability 161 void module_reads_do(ModuleClosure* const f); 162 163 TRACE_DEFINE_TRACE_ID_METHODS; 164 165 // Purge dead weak references out of reads list when any given class loader is unloaded. 166 void purge_reads(); 167 void delete_reads(); 168 169 // Special handling for unnamed module, one per class loader 170 static ModuleEntry* create_unnamed_module(ClassLoaderData* cld); 171 static ModuleEntry* create_boot_unnamed_module(ClassLoaderData* cld); 172 static ModuleEntry* new_unnamed_module_entry(Handle module_handle, ClassLoaderData* cld); 173 void delete_unnamed_module(); 174 175 void print(outputStream* st = tty); 176 void verify(); 177 }; 178 179 // Iterator interface 180 class ModuleClosure: public StackObj { 181 public: 182 virtual void do_module(ModuleEntry* const module) = 0; 183 }; 184 185 186 // The ModuleEntryTable is a Hashtable containing a list of all modules defined 187 // by a particular class loader. Each module is represented as a ModuleEntry node. 188 // 189 // Each ModuleEntryTable contains a _javabase_module field which allows for the 190 // creation of java.base's ModuleEntry very early in bootstrapping before the 191 // corresponding JVM_DefineModule call for java.base occurs during module system 192 // initialization. Setting up java.base's ModuleEntry early enables classes, 193 // loaded prior to the module system being initialized to be created with their 194 // PackageEntry node's correctly pointing at java.base's ModuleEntry. No class 195 // outside of java.base is allowed to be loaded pre-module system initialization. 196 // 197 // The ModuleEntryTable's lookup is lock free. 198 // 199 class ModuleEntryTable : public Hashtable<Symbol*, mtModule> { 200 friend class VMStructs; 201 public: 202 enum Constants { 203 _moduletable_entry_size = 109 // number of entries in module entry table 204 }; 205 206 private: 207 static ModuleEntry* _javabase_module; 208 209 ModuleEntry* new_entry(unsigned int hash, Handle module_handle, bool is_open, 210 Symbol* name, Symbol* version, Symbol* location, ClassLoaderData* loader_data); 211 void add_entry(int index, ModuleEntry* new_entry); 212 213 int entry_size() const { return BasicHashtable<mtModule>::entry_size(); } 214 215 ModuleEntry** bucket_addr(int i) { 216 return (ModuleEntry**)Hashtable<Symbol*, mtModule>::bucket_addr(i); 217 } 218 219 static unsigned int compute_hash(Symbol* name) { return ((name == NULL) ? 0 : (unsigned int)(name->identity_hash())); } 220 int index_for(Symbol* name) const { return hash_to_index(compute_hash(name)); } 221 222 public: 223 ModuleEntryTable(int table_size); 224 ~ModuleEntryTable(); 225 226 ModuleEntry* bucket(int i) { 227 return (ModuleEntry*)Hashtable<Symbol*, mtModule>::bucket(i); 228 } 229 230 // Create module in loader's module entry table, if already exists then 231 // return null. Assume Module_lock has been locked by caller. 232 ModuleEntry* locked_create_entry_or_null(Handle module_handle, 233 bool is_open, 234 Symbol* module_name, 235 Symbol* module_version, 236 Symbol* module_location, 237 ClassLoaderData* loader_data); 238 239 // Only lookup module within loader's module entry table. The table read is lock-free. 240 ModuleEntry* lookup_only(Symbol* name); 241 242 // purge dead weak references out of reads list 243 void purge_all_module_reads(); 244 245 // Special handling for java.base 246 static ModuleEntry* javabase_moduleEntry() { return _javabase_module; } 247 static void set_javabase_moduleEntry(ModuleEntry* java_base) { _javabase_module = java_base; } 248 249 static bool javabase_defined() { return ((_javabase_module != NULL) && 250 (_javabase_module->module() != NULL)); } 251 static void finalize_javabase(Handle module_handle, Symbol* version, Symbol* location); 252 static void patch_javabase_entries(Handle module_handle); 253 254 void print(outputStream* st = tty); 255 void verify(); 256 }; 257 258 #endif // SHARE_VM_CLASSFILE_MODULEENTRY_HPP