toolchain/gcc/libjava/java/lang/natClassLoader.cc

   1 // natClassLoader.cc - Implementation of java.lang.ClassLoader native methods.
   2
   3 /* Copyright (C) 1999, 2000, 2001, 2002, 2003  Free Software Foundation
   4
   5    This file is part of libgcj.
   6
   7 This software is copyrighted work licensed under the terms of the
   8 Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
   9 details.  */
  10
  11 /* Author: Kresten Krab Thorup <krab@gnu.org>  */
  12
  13 #include <config.h>
  14
  15 #include <stdlib.h>
  16 #include <string.h>
  17
  18 #include <gcj/cni.h>
  19 #include <jvm.h>
  20
  21 #include <java-threads.h>
  22 #include <java-interp.h>
  23
  24 #include <java/lang/Character.h>
  25 #include <java/lang/Thread.h>
  26 #include <java/lang/ClassLoader.h>
  27 #include <gnu/gcj/runtime/VMClassLoader.h>
  28 #include <java/lang/InternalError.h>
  29 #include <java/lang/IllegalAccessError.h>
  30 #include <java/lang/LinkageError.h>
  31 #include <java/lang/ClassFormatError.h>
  32 #include <java/lang/NoClassDefFoundError.h>
  33 #include <java/lang/ClassNotFoundException.h>
  34 #include <java/lang/ClassCircularityError.h>
  35 #include <java/lang/IncompatibleClassChangeError.h>
  36 #include <java/lang/VirtualMachineError.h>
  37 #include <java/lang/VMClassLoader.h>
  38 #include <java/lang/reflect/Modifier.h>
  39 #include <java/lang/Runtime.h>
  40 #include <java/lang/StringBuffer.h>
  41 #include <java/io/Serializable.h>
  42 #include <java/lang/Cloneable.h>
  43
  44 /////////// java.lang.ClassLoader native methods ////////////
  45
  46 java::lang::Class *
  47 java::lang::VMClassLoader::defineClass (java::lang::ClassLoader *loader,
  48                                         jstring name,
  49                                         jbyteArray data,
  50                                         jint offset,
  51                                         jint length,
  52                                         java::security::ProtectionDomain *pd)
  53 {
  54 #ifdef INTERPRETER
  55   jclass klass;
  56   klass = (jclass) JvAllocObject (&java::lang::Class::class$,
  57                                   sizeof (_Jv_InterpClass));
  58
  59   // Synchronize on the class, so that it is not attempted initialized
  60   // until we're done loading.
  61   JvSynchronize sync (klass);
  62
  63   // Record the defining loader.  For the system class loader, we
  64   // record NULL.
  65   if (loader != java::lang::ClassLoader::getSystemClassLoader())
  66     klass->loader = loader;
  67
  68   if (name != 0)
  69     {
  70       _Jv_Utf8Const *name2 = _Jv_makeUtf8Const (name);
  71
  72       if (! _Jv_VerifyClassName (name2))
  73         throw new java::lang::ClassFormatError
  74           (JvNewStringLatin1 ("erroneous class name"));
  75
  76       klass->name = name2;
  77     }
  78
  79   try
  80     {
  81       _Jv_DefineClass (klass, data, offset, length);
  82     }
  83   catch (java::lang::Throwable *ex)
  84     {
  85       klass->state = JV_STATE_ERROR;
  86       klass->notifyAll ();
  87
  88       _Jv_UnregisterClass (klass);
  89
  90       // If EX is not a ClassNotFoundException, that's ok, because we
  91       // account for the possibility in defineClass().
  92       throw ex;
  93     }
  94
  95   klass->protectionDomain = pd;
  96
  97   // if everything proceeded sucessfully, we're loaded.
  98   JvAssert (klass->state == JV_STATE_LOADED);
  99
 100   return klass;
 101
 102 #else // INTERPRETER
 103
 104   return 0;
 105 #endif
 106 }
 107
 108 // Finish linking a class.  Only called from ClassLoader::resolveClass.
 109 void
 110 java::lang::VMClassLoader::linkClass0 (java::lang::Class *klass)
 111 {
 112   _Jv_WaitForState (klass, JV_STATE_LINKED);
 113 }
 114
 115 void
 116 java::lang::VMClassLoader::markClassErrorState0 (java::lang::Class *klass)
 117 {
 118   klass->state = JV_STATE_ERROR;
 119   klass->notifyAll ();
 120 }
 121
 122 java::lang::ClassLoader *
 123 java::lang::VMClassLoader::getSystemClassLoaderInternal()
 124 {
 125   _Jv_InitClass (&gnu::gcj::runtime::VMClassLoader::class$);
 126   return gnu::gcj::runtime::VMClassLoader::instance;
 127 }
 128
 129 jclass
 130 java::lang::VMClassLoader::getPrimitiveClass (jchar type)
 131 {
 132   char sig[2];
 133   sig[0] = (char) type;
 134   sig[1] = '\0';
 135   return _Jv_FindClassFromSignature (sig, NULL);
 136 }
 137
 138 jclass
 139 java::lang::VMClassLoader::loadClass(jstring name, jboolean resolve)
 140 {
 141   _Jv_Utf8Const *utf = _Jv_makeUtf8Const (name);
 142   // FIXME: we culd make _Jv_FindClassFromSignature a template.
 143   jclass klass = _Jv_FindClassInCache (utf, NULL);
 144   if (klass && resolve)
 145     _Jv_InitClass (klass);
 146   return klass;
 147 }
 148
 149 void
 150 _Jv_WaitForState (jclass klass, int state)
 151 {
 152   if (klass->state >= state)
 153     return;
 154
 155   _Jv_MonitorEnter (klass) ;
 156
 157   if (state == JV_STATE_LINKED)
 158     {
 159       // Must call _Jv_PrepareCompiledClass while holding the class
 160       // mutex.
 161 #ifdef INTERPRETER
 162       if (_Jv_IsInterpretedClass (klass))
 163         _Jv_PrepareClass (klass);
 164 #endif
 165       _Jv_PrepareCompiledClass (klass);
 166       _Jv_MonitorExit (klass);
 167       return;
 168     }
 169
 170   java::lang::Thread *self = java::lang::Thread::currentThread();
 171
 172   // this is similar to the strategy for class initialization.
 173   // if we already hold the lock, just leave.
 174   while (klass->state <= state
 175          && klass->thread
 176          && klass->thread != self)
 177     klass->wait ();
 178
 179   _Jv_MonitorExit (klass);
 180
 181   if (klass->state == JV_STATE_ERROR)
 182     throw new java::lang::LinkageError;
 183 }
 184
 185 typedef unsigned int uaddr __attribute__ ((mode (pointer)));
 186
 187 /** This function does class-preparation for compiled classes.
 188     NOTE: It contains replicated functionality from
 189     _Jv_ResolvePoolEntry, and this is intentional, since that function
 190     lives in resolve.cc which is entirely conditionally compiled.
 191  */
 192 void
 193 _Jv_PrepareCompiledClass (jclass klass)
 194 {
 195   if (klass->state >= JV_STATE_LINKED)
 196     return;
 197
 198   // Short-circuit, so that mutually dependent classes are ok.
 199   klass->state = JV_STATE_LINKED;
 200
 201   _Jv_Constants *pool = &klass->constants;
 202
 203   // Resolve class constants first, since other constant pool
 204   // entries may rely on these.
 205   for (int index = 1; index < pool->size; ++index)
 206     {
 207       if (pool->tags[index] == JV_CONSTANT_Class)
 208         {
 209           _Jv_Utf8Const *name = pool->data[index].utf8;
 210
 211           jclass found;
 212           if (name->data[0] == '[')
 213             found = _Jv_FindClassFromSignature (&name->data[0],
 214                                                 klass->loader);
 215           else
 216             found = _Jv_FindClass (name, klass->loader);
 217
 218           if (! found)
 219             {
 220               jstring str = _Jv_NewStringUTF (name->data);
 221               throw new java::lang::NoClassDefFoundError (str);
 222             }
 223
 224           pool->data[index].clazz = found;
 225           pool->tags[index] |= JV_CONSTANT_ResolvedFlag;
 226         }
 227     }
 228
 229   // If superclass looks like a constant pool entry,
 230   // resolve it now.
 231   if ((uaddr) klass->superclass < pool->size)
 232     klass->superclass = pool->data[(int) klass->superclass].clazz;
 233
 234   // Likewise for interfaces.
 235   for (int i = 0; i < klass->interface_count; i++)
 236     if ((uaddr) klass->interfaces[i] < pool->size)
 237       klass->interfaces[i] = pool->data[(int) klass->interfaces[i]].clazz;
 238
 239   // Resolve the remaining constant pool entries.
 240   for (int index = 1; index < pool->size; ++index)
 241     {
 242       if (pool->tags[index] == JV_CONSTANT_String)
 243         {
 244           jstring str;
 245
 246           str = _Jv_NewStringUtf8Const (pool->data[index].utf8);
 247           pool->data[index].o = str;
 248           pool->tags[index] |= JV_CONSTANT_ResolvedFlag;
 249         }
 250     }
 251
 252 #ifdef INTERPRETER
 253   // FIXME: although the comment up top says that this function is
 254   // only called for compiled classes, it is actually called for every
 255   // class.
 256   if (! _Jv_IsInterpretedClass (klass))
 257     {
 258 #endif /* INTERPRETER */
 259       jfieldID f = JvGetFirstStaticField (klass);
 260       for (int n = JvNumStaticFields (klass); n > 0; --n)
 261         {
 262           int mod = f->getModifiers ();
 263           // If we have a static String field with a non-null initial
 264           // value, we know it points to a Utf8Const.
 265           _Jv_ResolveField(f, klass->loader);
 266           if (f->getClass () == &java::lang::String::class$
 267               && java::lang::reflect::Modifier::isStatic (mod))
 268             {
 269               jstring *strp = (jstring *) f->u.addr;
 270               if (*strp)
 271                 *strp = _Jv_NewStringUtf8Const ((_Jv_Utf8Const *) *strp);
 272             }
 273           f = f->getNextField ();
 274         }
 275 #ifdef INTERPRETER
 276     }
 277 #endif /* INTERPRETER */
 278
 279   klass->notifyAll ();
 280
 281   _Jv_PushClass (klass);
 282 }
 283
 284
 285 //
 286 //  A single class can have many "initiating" class loaders,
 287 //  and a single "defining" class loader.  The Defining
 288 //  class loader is what is returned from Class.getClassLoader()
 289 //  and is used when loading dependent classes during resolution.
 290 //  The set of initiating class loaders are used to ensure
 291 //  safety of linking, and is maintained in the hash table
 292 //  "initiated_classes".  A defining classloader is by definition also
 293 //  initiating, so we only store classes in this table if they have more
 294 //  than one class loader associated.
 295 //
 296
 297
 298 // Size of local hash table.
 299 #define HASH_LEN 1013
 300
 301 // Hash function for Utf8Consts.
 302 #define HASH_UTF(Utf) (((Utf)->hash) % HASH_LEN)
 303
 304 struct _Jv_LoaderInfo
 305 {
 306   _Jv_LoaderInfo          *next;
 307   java::lang::Class       *klass;
 308   java::lang::ClassLoader *loader;
 309 };
 310
 311 static _Jv_LoaderInfo *initiated_classes[HASH_LEN];
 312 static jclass loaded_classes[HASH_LEN];
 313
 314 // This is the root of a linked list of classes
 315
 316 \f
 317
 318 jclass
 319 _Jv_FindClassInCache (_Jv_Utf8Const *name, java::lang::ClassLoader *loader)
 320 {
 321   JvSynchronize sync (&java::lang::Class::class$);
 322   jint hash = HASH_UTF (name);
 323
 324   if (loader && loader == java::lang::ClassLoader::getSystemClassLoader())
 325     loader = NULL;
 326
 327   // first, if LOADER is a defining loader, then it is also initiating
 328   jclass klass;
 329   for (klass = loaded_classes[hash]; klass; klass = klass->next)
 330     {
 331       if (loader == klass->loader && _Jv_equalUtf8Consts (name, klass->name))
 332         break;
 333     }
 334
 335   // otherwise, it may be that the class in question was defined
 336   // by some other loader, but that the loading was initiated by
 337   // the loader in question.
 338   if (!klass)
 339     {
 340       _Jv_LoaderInfo *info;
 341       for (info = initiated_classes[hash]; info; info = info->next)
 342         {
 343           if (loader == info->loader
 344               && _Jv_equalUtf8Consts (name, info->klass->name))
 345             {
 346               klass = info->klass;
 347               break;
 348             }
 349         }
 350     }
 351
 352   return klass;
 353 }
 354
 355 void
 356 _Jv_UnregisterClass (jclass the_class)
 357 {
 358   JvSynchronize sync (&java::lang::Class::class$);
 359   jint hash = HASH_UTF(the_class->name);
 360
 361   jclass *klass = &(loaded_classes[hash]);
 362   for ( ; *klass; klass = &((*klass)->next))
 363     {
 364       if (*klass == the_class)
 365         {
 366           *klass = (*klass)->next;
 367           break;
 368         }
 369     }
 370
 371   _Jv_LoaderInfo **info = &(initiated_classes[hash]);
 372   for ( ; ; info = &((*info)->next))
 373     {
 374       while (*info && (*info)->klass == the_class)
 375         {
 376           _Jv_LoaderInfo *old = *info;
 377           *info = (*info)->next;
 378           _Jv_Free (old);
 379         }
 380
 381       if (*info == NULL)
 382         break;
 383     }
 384 }
 385
 386 void
 387 _Jv_RegisterInitiatingLoader (jclass klass, java::lang::ClassLoader *loader)
 388 {
 389   if (loader && loader == java::lang::ClassLoader::getSystemClassLoader())
 390     loader = NULL;
 391
 392   // This information can't be visible to the GC.
 393   _Jv_LoaderInfo *info
 394     = (_Jv_LoaderInfo *) _Jv_Malloc (sizeof(_Jv_LoaderInfo));
 395   jint hash = HASH_UTF(klass->name);
 396
 397   JvSynchronize sync (&java::lang::Class::class$);
 398   info->loader = loader;
 399   info->klass  = klass;
 400   info->next   = initiated_classes[hash];
 401   initiated_classes[hash] = info;
 402 }
 403
 404 // This function is called many times during startup, before main() is
 405 // run.  At that point in time we know for certain we are running
 406 // single-threaded, so we don't need to lock when adding classes to the
 407 // class chain.  At all other times, the caller should synchronize on
 408 // Class::class$.
 409 void
 410 _Jv_RegisterClasses (jclass *classes)
 411 {
 412   for (; *classes; ++classes)
 413     {
 414       jclass klass = *classes;
 415
 416       (*_Jv_RegisterClassHook) (klass);
 417
 418       // registering a compiled class causes
 419       // it to be immediately "prepared".
 420       if (klass->state == JV_STATE_NOTHING)
 421         klass->state = JV_STATE_COMPILED;
 422     }
 423 }
 424
 425 void
 426 _Jv_RegisterClassHookDefault (jclass klass)
 427 {
 428   jint hash = HASH_UTF (klass->name);
 429
 430   jclass check_class = loaded_classes[hash];
 431
 432   // If the class is already registered, don't re-register it.
 433   while (check_class != NULL)
 434     {
 435       if (check_class == klass)
 436         {
 437           // If you get this, it means you have the same class in two
 438           // different libraries.
 439 #define TEXT "Duplicate class registration: "
 440           // We size-limit MESSAGE so that you can't trash the stack.
 441           char message[200];
 442           strcpy (message, TEXT);
 443           strncpy (message + sizeof (TEXT) - 1, klass->name->data,
 444                    sizeof (message) - sizeof (TEXT));
 445           message[sizeof (message) - 1] = '\0';
 446           if (! gcj::runtimeInitialized)
 447             JvFail (message);
 448           else
 449             {
 450               java::lang::String *str = JvNewStringLatin1 (message);
 451               throw new java::lang::VirtualMachineError (str);
 452             }
 453         }
 454
 455       check_class = check_class->next;
 456     }
 457
 458   klass->next = loaded_classes[hash];
 459   loaded_classes[hash] = klass;
 460 }
 461
 462 // A pointer to a function that actually registers a class.
 463 // Normally _Jv_RegisterClassHookDefault, but could be some other function
 464 // that registers the class in e.g. a ClassLoader-local table.
 465 // Should synchronize on Class:class$ while setting/restore this variable.
 466
 467 void (*_Jv_RegisterClassHook) (jclass cl) = _Jv_RegisterClassHookDefault;
 468
 469 void
 470 _Jv_RegisterClass (jclass klass)
 471 {
 472   jclass classes[2];
 473   classes[0] = klass;
 474   classes[1] = NULL;
 475   _Jv_RegisterClasses (classes);
 476 }
 477
 478 jclass
 479 _Jv_FindClass (_Jv_Utf8Const *name, java::lang::ClassLoader *loader)
 480 {
 481   jclass klass = _Jv_FindClassInCache (name, loader);
 482
 483   if (! klass)
 484     {
 485       jstring sname = _Jv_NewStringUTF (name->data);
 486
 487       java::lang::ClassLoader *sys
 488         = java::lang::ClassLoader::getSystemClassLoader ();
 489
 490       if (loader)
 491         {
 492           // Load using a user-defined loader, jvmspec 5.3.2
 493           klass = loader->loadClass(sname, false);
 494
 495           // If "loader" delegated the loadClass operation to another
 496           // loader, explicitly register that it is also an initiating
 497           // loader of the given class.
 498           java::lang::ClassLoader *delegate = (loader == sys
 499                                                ? NULL
 500                                                : loader);
 501           if (klass && klass->getClassLoaderInternal () != delegate)
 502             _Jv_RegisterInitiatingLoader (klass, loader);
 503         }
 504       else
 505         {
 506           // Load using the bootstrap loader jvmspec 5.3.1.
 507           klass = sys->loadClass (sname, false);
 508
 509           // Register that we're an initiating loader.
 510           if (klass)
 511             _Jv_RegisterInitiatingLoader (klass, 0);
 512         }
 513     }
 514   else
 515     {
 516       // we need classes to be in the hash while
 517       // we're loading, so that they can refer to themselves.
 518       _Jv_WaitForState (klass, JV_STATE_LOADED);
 519     }
 520
 521   return klass;
 522 }
 523
 524 jclass
 525 _Jv_NewClass (_Jv_Utf8Const *name, jclass superclass,
 526               java::lang::ClassLoader *loader)
 527 {
 528   jclass ret = (jclass) JvAllocObject (&java::lang::Class::class$);
 529   ret->name = name;
 530   ret->superclass = superclass;
 531   ret->loader = loader;
 532
 533   _Jv_RegisterClass (ret);
 534
 535   return ret;
 536 }
 537
 538 static _Jv_IDispatchTable *array_idt = NULL;
 539 static jshort array_depth = 0;
 540 static jclass *array_ancestors = NULL;
 541
 542 // Create a class representing an array of ELEMENT and store a pointer to it
 543 // in element->arrayclass. LOADER is the ClassLoader which _initiated_ the
 544 // instantiation of this array. ARRAY_VTABLE is the vtable to use for the new
 545 // array class. This parameter is optional.
 546 void
 547 _Jv_NewArrayClass (jclass element, java::lang::ClassLoader *loader,
 548                    _Jv_VTable *array_vtable)
 549 {
 550   JvSynchronize sync (element);
 551
 552   _Jv_Utf8Const *array_name;
 553   int len;
 554
 555   if (element->arrayclass)
 556     return;
 557
 558   if (element->isPrimitive())
 559     {
 560       if (element == JvPrimClass (void))
 561         throw new java::lang::ClassNotFoundException ();
 562       len = 3;
 563     }
 564   else
 565     len = element->name->length + 5;
 566
 567   {
 568     char signature[len];
 569     int index = 0;
 570     signature[index++] = '[';
 571     // Compute name of array class.
 572     if (element->isPrimitive())
 573       {
 574         signature[index++] = (char) element->method_count;
 575       }
 576     else
 577       {
 578         size_t length = element->name->length;
 579         const char *const name = element->name->data;
 580         if (name[0] != '[')
 581           signature[index++] = 'L';
 582         memcpy (&signature[index], name, length);
 583         index += length;
 584         if (name[0] != '[')
 585           signature[index++] = ';';
 586       }
 587     array_name = _Jv_makeUtf8Const (signature, index);
 588   }
 589
 590   // Create new array class.
 591   jclass array_class = _Jv_NewClass (array_name, &java::lang::Object::class$,
 592                                      element->loader);
 593
 594   // Note that `vtable_method_count' doesn't include the initial
 595   // gc_descr slot.
 596   JvAssert (java::lang::Object::class$.vtable_method_count
 597             == NUM_OBJECT_METHODS);
 598   int dm_count = java::lang::Object::class$.vtable_method_count;
 599
 600   // Create a new vtable by copying Object's vtable.
 601   _Jv_VTable *vtable;
 602   if (array_vtable)
 603     vtable = array_vtable;
 604   else
 605     vtable = _Jv_VTable::new_vtable (dm_count);
 606   vtable->clas = array_class;
 607   vtable->gc_descr = java::lang::Object::class$.vtable->gc_descr;
 608   for (int i = 0; i < dm_count; ++i)
 609     vtable->set_method (i, java::lang::Object::class$.vtable->get_method (i));
 610
 611   array_class->vtable = vtable;
 612   array_class->vtable_method_count
 613     = java::lang::Object::class$.vtable_method_count;
 614
 615   // Stash the pointer to the element type.
 616   array_class->methods = (_Jv_Method *) element;
 617
 618   // Register our interfaces.
 619   static jclass interfaces[] =
 620     {
 621       &java::lang::Cloneable::class$,
 622       &java::io::Serializable::class$
 623     };
 624   array_class->interfaces = interfaces;
 625   array_class->interface_count = sizeof interfaces / sizeof interfaces[0];
 626
 627   // Since all array classes have the same interface dispatch table, we can
 628   // cache one and reuse it. It is not necessary to synchronize this.
 629   if (!array_idt)
 630     {
 631       _Jv_PrepareConstantTimeTables (array_class);
 632       array_idt = array_class->idt;
 633       array_depth = array_class->depth;
 634       array_ancestors = array_class->ancestors;
 635     }
 636   else
 637     {
 638       array_class->idt = array_idt;
 639       array_class->depth = array_depth;
 640       array_class->ancestors = array_ancestors;
 641     }
 642
 643   using namespace java::lang::reflect;
 644   {
 645     // Array classes are "abstract final"...
 646     _Jv_ushort accflags = Modifier::FINAL | Modifier::ABSTRACT;
 647     // ... and inherit accessibility from element type, per vmspec 5.3.3.2
 648     accflags |= (element->accflags & Modifier::PUBLIC);
 649     accflags |= (element->accflags & Modifier::PROTECTED);
 650     accflags |= (element->accflags & Modifier::PRIVATE);
 651     array_class->accflags = accflags;
 652   }
 653
 654   // An array class has no visible instance fields. "length" is invisible to
 655   // reflection.
 656
 657   // say this class is initialized and ready to go!
 658   array_class->state = JV_STATE_DONE;
 659
 660   // vmspec, section 5.3.3 describes this
 661   if (element->loader != loader)
 662     _Jv_RegisterInitiatingLoader (array_class, loader);
 663
 664   element->arrayclass = array_class;
 665 }
 666
 667 static jclass stack_head;
 668
 669 // These two functions form a stack of classes.   When a class is loaded
 670 // it is pushed onto the stack by the class loader; this is so that
 671 // StackTrace can quickly determine which classes have been loaded.
 672
 673 jclass
 674 _Jv_PopClass (void)
 675 {
 676   JvSynchronize sync (&java::lang::Class::class$);
 677   if (stack_head)
 678     {
 679       jclass tmp = stack_head;
 680       stack_head = tmp->chain;
 681       return tmp;
 682     }
 683   return NULL;
 684 }
 685
 686 void
 687 _Jv_PushClass (jclass k)
 688 {
 689   JvSynchronize sync (&java::lang::Class::class$);
 690   jclass tmp = stack_head;
 691   stack_head = k;
 692   k->chain = tmp;
 693 }