1 /*
   2  * Copyright (c) 2003, 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  *
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  24 
  25 #ifndef SHARE_VM_CLASSFILE_DICTIONARY_HPP
  26 #define SHARE_VM_CLASSFILE_DICTIONARY_HPP
  27 
  28 #include "classfile/protectionDomainCache.hpp"
  29 #include "classfile/systemDictionary.hpp"
  30 #include "oops/instanceKlass.hpp"
  31 #include "oops/oop.hpp"
  32 #include "runtime/orderAccess.hpp"
  33 #include "utilities/hashtable.hpp"
  34 #include "utilities/ostream.hpp"
  35 
  36 class DictionaryEntry;
  37 class BoolObjectClosure;
  38 
  39 //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  40 // The data structure for the class loader data dictionaries (and the shared system
  41 // dictionary).
  42 
  43 class Dictionary : public Hashtable<InstanceKlass*, mtClass> {
  44   friend class VMStructs;
  45 
  46   ClassLoaderData* _loader_data;  // backpointer to owning loader
  47   ClassLoaderData* loader_data() const { return _loader_data; }
  48 
  49   DictionaryEntry* get_entry(int index, unsigned int hash, Symbol* name);
  50 
  51 protected:
  52   DictionaryEntry* bucket(int i) const {
  53     return (DictionaryEntry*)Hashtable<InstanceKlass*, mtClass>::bucket(i);
  54   }
  55 
  56   // The following method is not MT-safe and must be done under lock.
  57   DictionaryEntry** bucket_addr(int i) {
  58     return (DictionaryEntry**)Hashtable<InstanceKlass*, mtClass>::bucket_addr(i);
  59   }
  60 
  61   void add_entry(int index, DictionaryEntry* new_entry) {
  62     Hashtable<InstanceKlass*, mtClass>::add_entry(index, (HashtableEntry<InstanceKlass*, mtClass>*)new_entry);
  63   }
  64 
  65   void free_entry(DictionaryEntry* entry);
  66 
  67   static size_t entry_size();
  68 public:
  69   Dictionary(ClassLoaderData* loader_data, int table_size);
  70   Dictionary(ClassLoaderData* loader_data, int table_size, HashtableBucket<mtClass>* t, int number_of_entries);
  71   ~Dictionary();
  72 
  73   DictionaryEntry* new_entry(unsigned int hash, InstanceKlass* klass);
  74 
  75   void add_klass(int index, unsigned int hash, Symbol* class_name, InstanceKlass* obj);
  76 
  77   InstanceKlass* find_class(int index, unsigned int hash, Symbol* name);
  78 
  79   InstanceKlass* find_shared_class(int index, unsigned int hash, Symbol* name);
  80 
  81   // GC support
  82   void oops_do(OopClosure* f);
  83   void roots_oops_do(OopClosure* strong, OopClosure* weak);
  84 
  85   void classes_do(void f(InstanceKlass*));
  86   void classes_do(void f(InstanceKlass*, TRAPS), TRAPS);
  87   void all_entries_do(void f(InstanceKlass*, ClassLoaderData*));
  88   void classes_do(MetaspaceClosure* it);
  89 
  90   void unlink(BoolObjectClosure* is_alive);
  91   void remove_classes_in_error_state();
  92 
  93   // Unload classes whose defining loaders are unloaded
  94   void do_unloading();
  95 
  96   // Protection domains
  97   InstanceKlass* find(int index, unsigned int hash, Symbol* name, Handle protection_domain);
  98   bool is_valid_protection_domain(int index, unsigned int hash,
  99                                   Symbol* name,
 100                                   Handle protection_domain);
 101   void add_protection_domain(int index, unsigned int hash,
 102                              InstanceKlass* klass,
 103                              Handle protection_domain, TRAPS);
 104 
 105   // Sharing support
 106   void reorder_dictionary_for_sharing();
 107 
 108   void print_on(outputStream* st) const;
 109   void verify();
 110 };
 111 
 112 // An entry in the class loader data dictionaries, this describes a class as
 113 // { InstanceKlass*, protection_domain }.
 114 
 115 class DictionaryEntry : public HashtableEntry<InstanceKlass*, mtClass> {
 116   friend class VMStructs;
 117  private:
 118   // Contains the set of approved protection domains that can access
 119   // this dictionary entry.
 120   //
 121   // This protection domain set is a set of tuples:
 122   //
 123   // (InstanceKlass C, initiating class loader ICL, Protection Domain PD)
 124   //
 125   // [Note that C.protection_domain(), which is stored in the java.lang.Class
 126   // mirror of C, is NOT the same as PD]
 127   //
 128   // If such an entry (C, ICL, PD) exists in the table, it means that
 129   // it is okay for a class Foo to reference C, where
 130   //
 131   //    Foo.protection_domain() == PD, and
 132   //    Foo's defining class loader == ICL
 133   //
 134   // The usage of the PD set can be seen in SystemDictionary::validate_protection_domain()
 135   // It is essentially a cache to avoid repeated Java up-calls to
 136   // ClassLoader.checkPackageAccess().
 137   //
 138   ProtectionDomainEntry* volatile _pd_set;
 139 
 140  public:
 141   // Tells whether a protection is in the approved set.
 142   bool contains_protection_domain(oop protection_domain) const;
 143   // Adds a protection domain to the approved set.
 144   void add_protection_domain(Dictionary* dict, Handle protection_domain);
 145 
 146   InstanceKlass* instance_klass() const { return literal(); }
 147   InstanceKlass** klass_addr() { return (InstanceKlass**)literal_addr(); }
 148 
 149   DictionaryEntry* next() const {
 150     return (DictionaryEntry*)HashtableEntry<InstanceKlass*, mtClass>::next();
 151   }
 152 
 153   DictionaryEntry** next_addr() {
 154     return (DictionaryEntry**)HashtableEntry<InstanceKlass*, mtClass>::next_addr();
 155   }
 156 
 157   ProtectionDomainEntry* pd_set() const            { return _pd_set; }
 158   void set_pd_set(ProtectionDomainEntry* new_head) {  _pd_set = new_head; }
 159 
 160   ProtectionDomainEntry* pd_set_acquire() const    {
 161     return (ProtectionDomainEntry*)OrderAccess::load_ptr_acquire(&_pd_set);
 162   }
 163   void release_set_pd_set(ProtectionDomainEntry* new_head) {
 164     OrderAccess::release_store_ptr(&_pd_set, new_head);
 165   }
 166 
 167   // Tells whether the initiating class' protection domain can access the klass in this entry
 168   bool is_valid_protection_domain(Handle protection_domain) {
 169     if (!ProtectionDomainVerification) return true;
 170     if (!SystemDictionary::has_checkPackageAccess()) return true;
 171 
 172     return protection_domain() == NULL
 173          ? true
 174          : contains_protection_domain(protection_domain());
 175   }
 176 
 177   void verify_protection_domain_set() {
 178     for (ProtectionDomainEntry* current = pd_set();
 179                                 current != NULL;
 180                                 current = current->_next) {
 181       current->_pd_cache->protection_domain()->verify();
 182     }
 183   }
 184 
 185   bool equals(const Symbol* class_name) const {
 186     InstanceKlass* klass = (InstanceKlass*)literal();
 187     return (klass->name() == class_name);
 188   }
 189 
 190   void print_count(outputStream *st) {
 191     int count = 0;
 192     for (ProtectionDomainEntry* current = pd_set();
 193                                 current != NULL;
 194                                 current = current->_next) {
 195       count++;
 196     }
 197     st->print_cr("pd set count = #%d", count);
 198   }
 199 
 200   void verify();
 201 };
 202 
 203 // Entry in a SymbolPropertyTable, mapping a single Symbol*
 204 // to a managed and an unmanaged pointer.
 205 class SymbolPropertyEntry : public HashtableEntry<Symbol*, mtSymbol> {
 206   friend class VMStructs;
 207  private:
 208   intptr_t _symbol_mode;  // secondary key
 209   Method*   _method;
 210   oop       _method_type;
 211 
 212  public:
 213   Symbol* symbol() const            { return literal(); }
 214 
 215   intptr_t symbol_mode() const      { return _symbol_mode; }
 216   void set_symbol_mode(intptr_t m)  { _symbol_mode = m; }
 217 
 218   Method*        method() const     { return _method; }
 219   void set_method(Method* p)        { _method = p; }
 220 
 221   oop      method_type() const      { return _method_type; }
 222   oop*     method_type_addr()       { return &_method_type; }
 223   void set_method_type(oop p)       { _method_type = p; }
 224 
 225   SymbolPropertyEntry* next() const {
 226     return (SymbolPropertyEntry*)HashtableEntry<Symbol*, mtSymbol>::next();
 227   }
 228 
 229   SymbolPropertyEntry** next_addr() {
 230     return (SymbolPropertyEntry**)HashtableEntry<Symbol*, mtSymbol>::next_addr();
 231   }
 232 
 233   void print_entry(outputStream* st) const {
 234     symbol()->print_value_on(st);
 235     st->print("/mode=" INTX_FORMAT, symbol_mode());
 236     st->print(" -> ");
 237     bool printed = false;
 238     if (method() != NULL) {
 239       method()->print_value_on(st);
 240       printed = true;
 241     }
 242     if (method_type() != NULL) {
 243       if (printed)  st->print(" and ");
 244       st->print(INTPTR_FORMAT, p2i((void *)method_type()));
 245       printed = true;
 246     }
 247     st->print_cr(printed ? "" : "(empty)");
 248   }
 249 };
 250 
 251 // A system-internal mapping of symbols to pointers, both managed
 252 // and unmanaged.  Used to record the auto-generation of each method
 253 // MethodHandle.invoke(S)T, for all signatures (S)T.
 254 class SymbolPropertyTable : public Hashtable<Symbol*, mtSymbol> {
 255   friend class VMStructs;
 256 private:
 257   SymbolPropertyEntry* bucket(int i) {
 258     return (SymbolPropertyEntry*) Hashtable<Symbol*, mtSymbol>::bucket(i);
 259   }
 260 
 261   // The following method is not MT-safe and must be done under lock.
 262   SymbolPropertyEntry** bucket_addr(int i) {
 263     return (SymbolPropertyEntry**) Hashtable<Symbol*, mtSymbol>::bucket_addr(i);
 264   }
 265 
 266   void add_entry(int index, SymbolPropertyEntry* new_entry) {
 267     ShouldNotReachHere();
 268   }
 269   void set_entry(int index, SymbolPropertyEntry* new_entry) {
 270     ShouldNotReachHere();
 271   }
 272 
 273   SymbolPropertyEntry* new_entry(unsigned int hash, Symbol* symbol, intptr_t symbol_mode) {
 274     SymbolPropertyEntry* entry = (SymbolPropertyEntry*) Hashtable<Symbol*, mtSymbol>::new_entry(hash, symbol);
 275     // Hashtable with Symbol* literal must increment and decrement refcount.
 276     symbol->increment_refcount();
 277     entry->set_symbol_mode(symbol_mode);
 278     entry->set_method(NULL);
 279     entry->set_method_type(NULL);
 280     return entry;
 281   }
 282 
 283 public:
 284   SymbolPropertyTable(int table_size);
 285   SymbolPropertyTable(int table_size, HashtableBucket<mtSymbol>* t, int number_of_entries);
 286 
 287   void free_entry(SymbolPropertyEntry* entry) {
 288     // decrement Symbol refcount here because hashtable doesn't.
 289     entry->literal()->decrement_refcount();
 290     Hashtable<Symbol*, mtSymbol>::free_entry(entry);
 291   }
 292 
 293   unsigned int compute_hash(Symbol* sym, intptr_t symbol_mode) {
 294     // Use the regular identity_hash.
 295     return Hashtable<Symbol*, mtSymbol>::compute_hash(sym) ^ symbol_mode;
 296   }
 297 
 298   int index_for(Symbol* name, intptr_t symbol_mode) {
 299     return hash_to_index(compute_hash(name, symbol_mode));
 300   }
 301 
 302   // need not be locked; no state change
 303   SymbolPropertyEntry* find_entry(int index, unsigned int hash, Symbol* name, intptr_t name_mode);
 304 
 305   // must be done under SystemDictionary_lock
 306   SymbolPropertyEntry* add_entry(int index, unsigned int hash, Symbol* name, intptr_t name_mode);
 307 
 308   // GC support
 309   void oops_do(OopClosure* f);
 310 
 311   void methods_do(void f(Method*));
 312 
 313   void verify();
 314 };
 315 #endif // SHARE_VM_CLASSFILE_DICTIONARY_HPP