1 /* 2 * Copyright (c) 2016, 2020, 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_CLASSFILE_MODULEENTRY_HPP 26 #define SHARE_CLASSFILE_MODULEENTRY_HPP 27 28 #include "jni.h" 29 #include "classfile/classLoaderData.hpp" 30 #include "classfile/vmSymbols.hpp" 31 #include "oops/oopHandle.hpp" 32 #include "oops/symbol.hpp" 33 #include "runtime/jniHandles.hpp" 34 #include "runtime/mutexLocker.hpp" 35 #include "utilities/growableArray.hpp" 36 #include "utilities/hashtable.hpp" 37 #include "utilities/macros.hpp" 38 #include "utilities/ostream.hpp" 39 #if INCLUDE_JFR 40 #include "jfr/support/jfrTraceIdExtension.hpp" 41 #endif 42 43 #define UNNAMED_MODULE "unnamed module" 44 #define UNNAMED_MODULE_LEN 14 45 #define JAVAPKG "java" 46 #define JAVAPKG_LEN 4 47 #define JAVA_BASE_NAME "java.base" 48 #define JAVA_BASE_NAME_LEN 9 49 50 template <class T> class Array; 51 class ModuleClosure; 52 53 // A ModuleEntry describes a module that has been defined by a call to JVM_DefineModule. 54 // It contains: 55 // - Symbol* containing the module's name. 56 // - pointer to the java.lang.Module for this module. 57 // - pointer to the java.security.ProtectionDomain shared by classes defined to this module. 58 // - ClassLoaderData*, class loader of this module. 59 // - a growable array containg other module entries that this module can read. 60 // - a flag indicating if this module can read all unnamed modules. 61 // 62 // The Mutex Module_lock is shared between ModuleEntry and PackageEntry, to lock either 63 // data structure. 64 class ModuleEntry : public HashtableEntry<Symbol*, mtModule> { 65 private: 66 OopHandle _module; // java.lang.Module 67 OopHandle _shared_pd; // java.security.ProtectionDomain, cached 68 // for shared classes from this module 69 ClassLoaderData* _loader_data; 70 GrowableArray<ModuleEntry*>* _reads; // list of modules that are readable by this module 71 Symbol* _version; // module version number 72 Symbol* _location; // module location 73 CDS_ONLY(int _shared_path_index;) // >=0 if classes in this module are in CDS archive 74 bool _can_read_all_unnamed; 75 bool _has_default_read_edges; // JVMTI redefine/retransform support 76 bool _must_walk_reads; // walk module's reads list at GC safepoints to purge out dead modules 77 bool _is_open; // whether the packages in the module are all unqualifiedly exported 78 bool _is_patched; // whether the module is patched via --patch-module 79 CDS_JAVA_HEAP_ONLY(narrowOop _archived_module_narrow_oop;) 80 81 JFR_ONLY(DEFINE_TRACE_ID_FIELD;) 82 enum {MODULE_READS_SIZE = 101}; // Initial size of list of modules that the module can read. 83 84 public: 85 void init() { 86 _module = OopHandle(); 87 _shared_pd = OopHandle(); 88 _loader_data = NULL; 89 _reads = NULL; 90 _version = NULL; 91 _location = NULL; 92 _can_read_all_unnamed = false; 93 _has_default_read_edges = false; 94 _must_walk_reads = false; 95 _is_patched = false; 96 _is_open = false; 97 CDS_ONLY(_shared_path_index = -1); 98 } 99 100 Symbol* name() const { return literal(); } 101 void set_name(Symbol* n) { set_literal(n); } 102 103 oop module() const; 104 OopHandle module_handle() const { return _module; } 105 void set_module(OopHandle j) { _module = j; } 106 107 // The shared ProtectionDomain reference is set once the VM loads a shared class 108 // originated from the current Module. The referenced ProtectionDomain object is 109 // created by the ClassLoader when loading a class (shared or non-shared) from the 110 // Module for the first time. This ProtectionDomain object is used for all 111 // classes from the Module loaded by the same ClassLoader. 112 oop shared_protection_domain(); 113 void set_shared_protection_domain(ClassLoaderData *loader_data, Handle pd); 114 115 ClassLoaderData* loader_data() const { return _loader_data; } 116 117 void set_loader_data(ClassLoaderData* cld) { 118 assert(!cld->has_class_mirror_holder(), "Unexpected has_class_mirror_holder cld"); 119 _loader_data = cld; 120 } 121 122 Symbol* version() const { return _version; } 123 void set_version(Symbol* version); 124 125 Symbol* location() const { return _location; } 126 void set_location(Symbol* location); 127 bool should_show_version(); 128 129 bool can_read(ModuleEntry* m) const; 130 bool has_reads_list() const; 131 void add_read(ModuleEntry* m); 132 void set_read_walk_required(ClassLoaderData* m_loader_data); 133 134 bool is_open() const { return _is_open; } 135 void set_is_open(bool is_open); 136 137 bool is_named() const { return (name() != NULL); } 138 139 bool can_read_all_unnamed() const { 140 assert(is_named() || _can_read_all_unnamed == true, 141 "unnamed modules can always read all unnamed modules"); 142 return _can_read_all_unnamed; 143 } 144 145 // Modules can only go from strict to loose. 146 void set_can_read_all_unnamed() { _can_read_all_unnamed = true; } 147 148 bool has_default_read_edges() const { 149 return _has_default_read_edges; 150 } 151 152 // Sets true and returns the previous value. 153 bool set_has_default_read_edges() { 154 MutexLocker ml(Module_lock); 155 bool prev = _has_default_read_edges; 156 _has_default_read_edges = true; 157 return prev; 158 } 159 160 void set_is_patched() { 161 _is_patched = true; 162 CDS_ONLY(_shared_path_index = -1); // Mark all shared classes in this module invisible. 163 } 164 bool is_patched() { 165 return _is_patched; 166 } 167 168 ModuleEntry* next() const { 169 return (ModuleEntry*)HashtableEntry<Symbol*, mtModule>::next(); 170 } 171 ModuleEntry** next_addr() { 172 return (ModuleEntry**)HashtableEntry<Symbol*, mtModule>::next_addr(); 173 } 174 175 // iteration support for readability 176 void module_reads_do(ModuleClosure* const f); 177 178 // Purge dead weak references out of reads list when any given class loader is unloaded. 179 void purge_reads(); 180 void delete_reads(); 181 182 // Special handling for unnamed module, one per class loader 183 static ModuleEntry* create_unnamed_module(ClassLoaderData* cld); 184 static ModuleEntry* create_boot_unnamed_module(ClassLoaderData* cld); 185 static ModuleEntry* new_unnamed_module_entry(Handle module_handle, ClassLoaderData* cld); 186 void delete_unnamed_module(); 187 188 void print(outputStream* st = tty); 189 void verify(); 190 191 CDS_ONLY(int shared_path_index() { return _shared_path_index;}) 192 193 JFR_ONLY(DEFINE_TRACE_ID_METHODS;) 194 195 #if INCLUDE_CDS_JAVA_HEAP 196 ModuleEntry* allocate_archived_entry() const; 197 void init_as_archived_entry(); 198 void init_archived_oops(); 199 static ModuleEntry* get_archived_entry(ModuleEntry* orig_entry); 200 static Array<ModuleEntry*>* write_archived_entry_array(GrowableArray<ModuleEntry*>* array); 201 static GrowableArray<ModuleEntry*>* read_archived_entry_array(Array<ModuleEntry*>* archived_array); 202 void load_from_archive(ClassLoaderData* loader_data); 203 void restore_archive_oops(ClassLoaderData* loader_data); 204 #endif 205 }; 206 207 // Iterator interface 208 class ModuleClosure: public StackObj { 209 public: 210 virtual void do_module(ModuleEntry* module) = 0; 211 }; 212 213 214 // The ModuleEntryTable is a Hashtable containing a list of all modules defined 215 // by a particular class loader. Each module is represented as a ModuleEntry node. 216 // 217 // Each ModuleEntryTable contains a _javabase_module field which allows for the 218 // creation of java.base's ModuleEntry very early in bootstrapping before the 219 // corresponding JVM_DefineModule call for java.base occurs during module system 220 // initialization. Setting up java.base's ModuleEntry early enables classes, 221 // loaded prior to the module system being initialized to be created with their 222 // PackageEntry node's correctly pointing at java.base's ModuleEntry. No class 223 // outside of java.base is allowed to be loaded pre-module system initialization. 224 // 225 // The ModuleEntryTable's lookup is lock free. 226 // 227 class ModuleEntryTable : public Hashtable<Symbol*, mtModule> { 228 friend class VMStructs; 229 public: 230 enum Constants { 231 _moduletable_entry_size = 109 // number of entries in module entry table 232 }; 233 234 private: 235 static ModuleEntry* _javabase_module; 236 237 ModuleEntry* new_entry(unsigned int hash, Handle module_handle, bool is_open, 238 Symbol* name, Symbol* version, Symbol* location, ClassLoaderData* loader_data); 239 void add_entry(int index, ModuleEntry* new_entry); 240 241 int entry_size() const { return BasicHashtable<mtModule>::entry_size(); } 242 243 ModuleEntry** bucket_addr(int i) { 244 return (ModuleEntry**)Hashtable<Symbol*, mtModule>::bucket_addr(i); 245 } 246 247 static unsigned int compute_hash(Symbol* name) { return ((name == NULL) ? 0 : (unsigned int)(name->identity_hash())); } 248 int index_for(Symbol* name) const { return hash_to_index(compute_hash(name)); } 249 250 public: 251 ModuleEntryTable(int table_size); 252 ~ModuleEntryTable(); 253 254 ModuleEntry* bucket(int i) { 255 return (ModuleEntry*)Hashtable<Symbol*, mtModule>::bucket(i); 256 } 257 258 // Create module in loader's module entry table. Assume Module_lock 259 // has been locked by caller. 260 ModuleEntry* locked_create_entry(Handle module_handle, 261 bool is_open, 262 Symbol* module_name, 263 Symbol* module_version, 264 Symbol* module_location, 265 ClassLoaderData* loader_data); 266 267 // Only lookup module within loader's module entry table. The table read is lock-free. 268 ModuleEntry* lookup_only(Symbol* name); 269 270 // purge dead weak references out of reads list 271 void purge_all_module_reads(); 272 273 // Special handling for java.base 274 static ModuleEntry* javabase_moduleEntry() { return _javabase_module; } 275 static void set_javabase_moduleEntry(ModuleEntry* java_base) { 276 assert(_javabase_module == NULL, "_javabase_module is already defined"); 277 _javabase_module = java_base; 278 } 279 280 static bool javabase_defined() { return ((_javabase_module != NULL) && 281 (_javabase_module->module() != NULL)); } 282 static void finalize_javabase(Handle module_handle, Symbol* version, Symbol* location); 283 static void patch_javabase_entries(Handle module_handle); 284 285 void print(outputStream* st = tty); 286 void verify(); 287 288 #if INCLUDE_CDS_JAVA_HEAP 289 Array<ModuleEntry*>* allocate_archived_entries(); 290 void init_archived_entries(Array<ModuleEntry*>* archived_modules); 291 void init_archived_oops(Array<ModuleEntry*>* archived_modules); 292 void load_archived_entries(ClassLoaderData* loader_data, 293 Array<ModuleEntry*>* archived_modules); 294 void restore_archived_oops(ClassLoaderData* loader_data, 295 Array<ModuleEntry*>* archived_modules); 296 #endif 297 }; 298 299 #endif // SHARE_CLASSFILE_MODULEENTRY_HPP