1 /*

     2  * Copyright 2003-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  *

    23  */

    24 

    25 class DictionaryEntry;

    26 

    27 //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    28 // The data structure for the system dictionary (and the shared system

    29 // dictionary).

    30 

    31 class Dictionary : public TwoOopHashtable {

    32   friend class VMStructs;

    33 private:

    34   // current iteration index.

    35   static int                    _current_class_index;

    36   // pointer to the current hash table entry.

    37   static DictionaryEntry*       _current_class_entry;

    38 

    39   DictionaryEntry* get_entry(int index, unsigned int hash,

    40                              symbolHandle name, Handle loader);

    41 

    42   DictionaryEntry* bucket(int i) {

    43     return (DictionaryEntry*)Hashtable::bucket(i);

    44   }

    45 

    46   // The following method is not MT-safe and must be done under lock.

    47   DictionaryEntry** bucket_addr(int i) {

    48     return (DictionaryEntry**)Hashtable::bucket_addr(i);

    49   }

    50 

    51   void add_entry(int index, DictionaryEntry* new_entry) {

    52     Hashtable::add_entry(index, (HashtableEntry*)new_entry);

    53   }

    54 

    55 

    56 public:

    57   Dictionary(int table_size);

    58   Dictionary(int table_size, HashtableBucket* t, int number_of_entries);

    59 

    60   DictionaryEntry* new_entry(unsigned int hash, klassOop klass, oop loader);

    61 

    62   DictionaryEntry* new_entry();

    63 

    64   void free_entry(DictionaryEntry* entry);

    65 

    66   void add_klass(symbolHandle class_name, Handle class_loader,KlassHandle obj);

    67 

    68   klassOop find_class(int index, unsigned int hash,

    69                       symbolHandle name, Handle loader);

    70 

    71   klassOop find_shared_class(int index, unsigned int hash, symbolHandle name);

    72 

    73   // Compiler support

    74   klassOop try_get_next_class();

    75 

    76   // GC support

    77 

    78   void oops_do(OopClosure* f);

    79   void always_strong_classes_do(OopClosure* blk);

    80   void classes_do(void f(klassOop));

    81   void classes_do(void f(klassOop, TRAPS), TRAPS);

    82   void classes_do(void f(klassOop, oop));

    83   void classes_do(void f(klassOop, oop, TRAPS), TRAPS);

    84 

    85   void methods_do(void f(methodOop));

    86 

    87 

    88   // Classes loaded by the bootstrap loader are always strongly reachable.

    89   // If we're not doing class unloading, all classes are strongly reachable.

    90   static bool is_strongly_reachable(oop class_loader, oop klass) {

    91     assert (klass != NULL, "should have non-null klass");

    92     return (class_loader == NULL || !ClassUnloading);

    93   }

    94 

    95   // Unload (that is, break root links to) all unmarked classes and

    96   // loaders.  Returns "true" iff something was unloaded.

    97   bool do_unloading(BoolObjectClosure* is_alive);

    98 

    99   // Protection domains

   100   klassOop find(int index, unsigned int hash, symbolHandle name,

   101                 Handle loader, Handle protection_domain, TRAPS);

   102   bool is_valid_protection_domain(int index, unsigned int hash,

   103                                   symbolHandle name, Handle class_loader,

   104                                   Handle protection_domain);

   105   void add_protection_domain(int index, unsigned int hash,

   106                              instanceKlassHandle klass, Handle loader,

   107                              Handle protection_domain, TRAPS);

   108 

   109   // Sharing support

   110   void dump(SerializeOopClosure* soc);

   111   void restore(SerializeOopClosure* soc);

   112   void reorder_dictionary();

   113 

   114 

   115 #ifndef PRODUCT

   116   void print();

   117 #endif

   118   void verify();

   119 };

   120 

   121 // The following classes can be in dictionary.cpp, but we need these

   122 // to be in header file so that SA's vmStructs can access.

   123 

   124 class ProtectionDomainEntry :public CHeapObj {

   125   friend class VMStructs;

   126  public:

   127   ProtectionDomainEntry* _next;

   128   oop                    _protection_domain;

   129 

   130   ProtectionDomainEntry(oop protection_domain, ProtectionDomainEntry* next) {

   131     _protection_domain = protection_domain;

   132     _next              = next;

   133   }

   134 

   135   ProtectionDomainEntry* next() { return _next; }

   136   oop protection_domain() { return _protection_domain; }

   137 };

   138 

   139 // An entry in the system dictionary, this describes a class as

   140 // { klassOop, loader, protection_domain }.

   141 

   142 class DictionaryEntry : public HashtableEntry {

   143   friend class VMStructs;

   144  private:

   145   // Contains the set of approved protection domains that can access

   146   // this system dictionary entry.

   147   ProtectionDomainEntry* _pd_set;

   148   oop                    _loader;

   149 

   150 

   151  public:

   152   // Tells whether a protection is in the approved set.

   153   bool contains_protection_domain(oop protection_domain) const;

   154   // Adds a protection domain to the approved set.

   155   void add_protection_domain(oop protection_domain);

   156 

   157   klassOop klass() const { return (klassOop)literal(); }

   158   klassOop* klass_addr() { return (klassOop*)literal_addr(); }

   159 

   160   DictionaryEntry* next() const {

   161     return (DictionaryEntry*)HashtableEntry::next();

   162   }

   163 

   164   DictionaryEntry** next_addr() {

   165     return (DictionaryEntry**)HashtableEntry::next_addr();

   166   }

   167 

   168   oop loader() const { return _loader; }

   169   void set_loader(oop loader) { _loader = loader; }

   170   oop* loader_addr() { return &_loader; }

   171 

   172   ProtectionDomainEntry* pd_set() const { return _pd_set; }

   173   void set_pd_set(ProtectionDomainEntry* pd_set) { _pd_set = pd_set; }

   174 

   175   bool has_protection_domain() { return _pd_set != NULL; }

   176 

   177   // Tells whether the initiating class' protection can access the this _klass

   178   bool is_valid_protection_domain(Handle protection_domain) {

   179     if (!ProtectionDomainVerification) return true;

   180     if (!SystemDictionary::has_checkPackageAccess()) return true;

   181 

   182     return protection_domain() == NULL

   183          ? true

   184          : contains_protection_domain(protection_domain());

   185   }

   186 

   187 

   188   void protection_domain_set_oops_do(OopClosure* f) {

   189     for (ProtectionDomainEntry* current = _pd_set;

   190                                 current != NULL;

   191                                 current = current->_next) {

   192       f->do_oop(&(current->_protection_domain));

   193     }

   194   }

   195 

   196   void verify_protection_domain_set() {

   197     for (ProtectionDomainEntry* current = _pd_set;

   198                                 current != NULL;

   199                                 current = current->_next) {

   200       current->_protection_domain->verify();

   201     }

   202   }

   203 

   204   bool equals(symbolOop class_name, oop class_loader) const {

   205     klassOop klass = (klassOop)literal();

   206     return (instanceKlass::cast(klass)->name() == class_name &&

   207             _loader == class_loader);

   208   }

   209 

   210   void print() {

   211     int count = 0;

   212     for (ProtectionDomainEntry* current = _pd_set;

   213                                 current != NULL;

   214                                 current = current->_next) {

   215       count++;

   216     }

   217     tty->print_cr("pd set = #%d", count);

   218   }

   219 };