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/symbol.hpp" 31 #include "prims/jni.h" 32 #include "runtime/jniHandles.hpp" 33 #include "runtime/mutexLocker.hpp" 34 #include "trace/traceMacros.hpp" 35 #include "utilities/growableArray.hpp" 36 #include "utilities/hashtable.hpp" 37 #include "utilities/ostream.hpp" 38 39 #define UNNAMED_MODULE "Unnamed Module" 40 #define JAVAPKG "java" 41 #define JAVAPKG_LEN 4 42 #define JAVA_BASE_NAME "java.base" 43 44 class ModuleClosure; 45 46 // A ModuleEntry describes a module that has been defined by a call to JVM_DefineModule. 47 // It contains: 48 // - Symbol* containing the module's name. 49 // - pointer to the java.lang.Module for this module. 50 // - pointer to the java.security.ProtectionDomain shared by classes defined to this module. 51 // - ClassLoaderData*, class loader of this module. 52 // - a growable array containg other module entries that this module can read. 53 // - a flag indicating if this module can read all unnamed modules. 54 // 55 // The Mutex Module_lock is shared between ModuleEntry and PackageEntry, to lock either 56 // data structure. 57 class ModuleEntry : public HashtableEntry<Symbol*, mtModule> { 58 private: 59 jobject _module; // java.lang.Module 60 jobject _pd; // java.security.ProtectionDomain, cached 61 // for shared classes from this module 62 ClassLoaderData* _loader_data; 63 GrowableArray<ModuleEntry*>* _reads; // list of modules that are readable by this module 64 Symbol* _version; // module version number 65 Symbol* _location; // module location 66 bool _can_read_all_unnamed; 67 bool _has_default_read_edges; // JVMTI redefine/retransform support 68 bool _must_walk_reads; // walk module's reads list at GC safepoints to purge out dead modules 69 bool _is_open; // whether the packages in the module are all unqualifiedly exported 70 bool _is_patched; // whether the module is patched via --patch-module 71 TRACE_DEFINE_TRACE_ID_FIELD; 72 enum {MODULE_READS_SIZE = 101}; // Initial size of list of modules that the module can read. 73 74 public: 75 void init() { 76 _module = NULL; 77 _loader_data = NULL; 78 _pd = NULL; 79 _reads = NULL; 80 _version = NULL; 81 _location = NULL; 82 _can_read_all_unnamed = false; 83 _has_default_read_edges = false; 84 _must_walk_reads = false; 85 _is_patched = false; 86 _is_open = false; 87 } 88 89 Symbol* name() const { return literal(); } 90 void set_name(Symbol* n) { set_literal(n); } 91 92 oop module() const { return JNIHandles::resolve(_module); } 93 jobject module_handle() const { return _module; } 94 void set_module(jobject j) { _module = j; } 95 96 // The shared ProtectionDomain reference is set once the VM loads a shared class 97 // originated from the current Module. The referenced ProtectionDomain object is 98 // created by the ClassLoader when loading a class (shared or non-shared) from the 99 // Module for the first time. This ProtectionDomain object is used for all 100 // classes from the Module loaded by the same ClassLoader. 101 Handle shared_protection_domain(); 102 void set_shared_protection_domain(ClassLoaderData *loader_data, Handle pd); 103 104 ClassLoaderData* loader_data() const { return _loader_data; } 105 void set_loader_data(ClassLoaderData* l) { _loader_data = l; } 106 107 Symbol* version() const { return _version; } 108 void set_version(Symbol* version); 109 110 Symbol* location() const { return _location; } 111 void set_location(Symbol* location); 112 bool is_non_jdk_module(); 113 114 bool can_read(ModuleEntry* m) const; 115 bool has_reads_list() const; 116 void add_read(ModuleEntry* m); 117 void set_read_walk_required(ClassLoaderData* m_loader_data); 118 119 bool is_open() const { return _is_open; } 120 void set_is_open(bool is_open); 121 122 bool is_named() const { return (name() != NULL); } 123 124 bool can_read_all_unnamed() const { 125 assert(is_named() || _can_read_all_unnamed == true, 126 "unnamed modules can always read all unnamed modules"); 127 return _can_read_all_unnamed; 128 } 129 130 // Modules can only go from strict to loose. 131 void set_can_read_all_unnamed() { _can_read_all_unnamed = true; } 132 133 bool has_default_read_edges() const { 134 return _has_default_read_edges; 135 } 136 137 // Sets true and returns the previous value. 138 bool set_has_default_read_edges() { 139 MutexLocker ml(Module_lock); 140 bool prev = _has_default_read_edges; 141 _has_default_read_edges = true; 142 return prev; 143 } 144 145 void set_is_patched() { 146 _is_patched = true; 147 } 148 bool is_patched() { 149 return _is_patched; 150 } 151 152 ModuleEntry* next() const { 153 return (ModuleEntry*)HashtableEntry<Symbol*, mtModule>::next(); 154 } 155 ModuleEntry** next_addr() { 156 return (ModuleEntry**)HashtableEntry<Symbol*, mtModule>::next_addr(); 157 } 158 159 // iteration support for readability 160 void module_reads_do(ModuleClosure* const f); 161 162 TRACE_DEFINE_TRACE_ID_METHODS; 163 164 // Purge dead weak references out of reads list when any given class loader is unloaded. 165 void purge_reads(); 166 void delete_reads(); 167 168 // Special handling for unnamed module, one per class loader 169 static ModuleEntry* create_unnamed_module(ClassLoaderData* cld); 170 static ModuleEntry* create_boot_unnamed_module(ClassLoaderData* cld); 171 static ModuleEntry* new_unnamed_module_entry(Handle module_handle, ClassLoaderData* cld); 172 void delete_unnamed_module(); 173 174 void print(outputStream* st = tty); 175 void verify(); 176 }; 177 178 // Iterator interface 179 class ModuleClosure: public StackObj { 180 public: 181 virtual void do_module(ModuleEntry* const module) = 0; 182 }; 183 184 185 // The ModuleEntryTable is a Hashtable containing a list of all modules defined 186 // by a particular class loader. Each module is represented as a ModuleEntry node. 187 // 188 // Each ModuleEntryTable contains a _javabase_module field which allows for the 189 // creation of java.base's ModuleEntry very early in bootstrapping before the 190 // corresponding JVM_DefineModule call for java.base occurs during module system 191 // initialization. Setting up java.base's ModuleEntry early enables classes, 192 // loaded prior to the module system being initialized to be created with their 193 // PackageEntry node's correctly pointing at java.base's ModuleEntry. No class 194 // outside of java.base is allowed to be loaded pre-module system initialization. 195 // 196 // The ModuleEntryTable's lookup is lock free. 197 // 198 class ModuleEntryTable : public Hashtable<Symbol*, mtModule> { 199 friend class VMStructs; 200 public: 201 enum Constants { 202 _moduletable_entry_size = 109 // number of entries in module entry table 203 }; 204 205 private: 206 static ModuleEntry* _javabase_module; 207 208 ModuleEntry* new_entry(unsigned int hash, Handle module_handle, bool is_open, 209 Symbol* name, Symbol* version, Symbol* location, ClassLoaderData* loader_data); 210 void add_entry(int index, ModuleEntry* new_entry); 211 212 int entry_size() const { return BasicHashtable<mtModule>::entry_size(); } 213 214 ModuleEntry** bucket_addr(int i) { 215 return (ModuleEntry**)Hashtable<Symbol*, mtModule>::bucket_addr(i); 216 } 217 218 static unsigned int compute_hash(Symbol* name) { return ((name == NULL) ? 0 : (unsigned int)(name->identity_hash())); } 219 int index_for(Symbol* name) const { return hash_to_index(compute_hash(name)); } 220 221 public: 222 ModuleEntryTable(int table_size); 223 ~ModuleEntryTable(); 224 225 ModuleEntry* bucket(int i) { 226 return (ModuleEntry*)Hashtable<Symbol*, mtModule>::bucket(i); 227 } 228 229 // Create module in loader's module entry table, if already exists then 230 // return null. Assume Module_lock has been locked by caller. 231 ModuleEntry* locked_create_entry_or_null(Handle module_handle, 232 bool is_open, 233 Symbol* module_name, 234 Symbol* module_version, 235 Symbol* module_location, 236 ClassLoaderData* loader_data); 237 238 // Only lookup module within loader's module entry table. The table read is lock-free. 239 ModuleEntry* lookup_only(Symbol* name); 240 241 // purge dead weak references out of reads list 242 void purge_all_module_reads(); 243 244 // Special handling for java.base 245 static ModuleEntry* javabase_moduleEntry() { return _javabase_module; } 246 static void set_javabase_moduleEntry(ModuleEntry* java_base) { _javabase_module = java_base; } 247 248 static bool javabase_defined() { return ((_javabase_module != NULL) && 249 (_javabase_module->module_handle() != NULL)); } 250 static void finalize_javabase(Handle module_handle, Symbol* version, Symbol* location); 251 static void patch_javabase_entries(Handle module_handle); 252 253 void print(outputStream* st = tty); 254 void verify(); 255 }; 256 257 #endif // SHARE_VM_CLASSFILE_MODULEENTRY_HPP