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 #include "precompiled.hpp"
  26 #include "classfile/classFileParser.hpp"
  27 #include "classfile/classLoader.hpp"
  28 #include "classfile/classLoaderData.inline.hpp"
  29 #include "classfile/javaAssertions.hpp"
  30 #include "classfile/javaClasses.hpp"
  31 #include "classfile/javaClasses.inline.hpp"
  32 #include "classfile/moduleEntry.hpp"
  33 #include "classfile/modules.hpp"
  34 #include "classfile/packageEntry.hpp"
  35 #include "classfile/stringTable.hpp"
  36 #include "classfile/symbolTable.hpp"
  37 #include "classfile/systemDictionary.hpp"
  38 #include "classfile/vmSymbols.hpp"
  39 #include "logging/log.hpp"
  40 #include "logging/logStream.hpp"
  41 #include "memory/resourceArea.hpp"
  42 #include "oops/instanceKlass.hpp"
  43 #include "prims/jvm.h"
  44 #include "runtime/arguments.hpp"
  45 #include "runtime/handles.inline.hpp"
  46 #include "runtime/javaCalls.hpp"
  47 #include "runtime/reflection.hpp"
  48 #include "utilities/stringUtils.hpp"
  49 #include "utilities/utf8.hpp"
  50 
  51 static bool verify_module_name(const char *module_name) {
  52   if (module_name == NULL) return false;
  53   int len = (int)strlen(module_name);
  54   return (len > 0 && len <= Symbol::max_length());
  55 }
  56 
  57 bool Modules::verify_package_name(const char* package_name) {
  58   if (package_name == NULL) return false;
  59   int len = (int)strlen(package_name);
  60   return (len > 0 && len <= Symbol::max_length() &&
  61     UTF8::is_legal_utf8((const unsigned char *)package_name, len, false) &&
  62     ClassFileParser::verify_unqualified_name(package_name, len,
  63     ClassFileParser::LegalClass));
  64 }
  65 
  66 static char* get_module_name(oop module, TRAPS) {
  67   oop name_oop = java_lang_Module::name(module);
  68   if (name_oop == NULL) {
  69     THROW_MSG_NULL(vmSymbols::java_lang_NullPointerException(), "Null module name");
  70   }
  71   char* module_name = java_lang_String::as_utf8_string(name_oop);
  72   if (!verify_module_name(module_name)) {
  73     THROW_MSG_NULL(vmSymbols::java_lang_IllegalArgumentException(),
  74                    err_msg("Invalid module name: %s",
  75                            module_name != NULL ? module_name : "NULL"));
  76   }
  77   return module_name;
  78 }
  79 
  80 static const char* get_module_version(jstring version) {
  81   if (version == NULL) {
  82     return NULL;
  83   }
  84   return java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(version));
  85 }
  86 
  87 static ModuleEntryTable* get_module_entry_table(Handle h_loader, TRAPS) {
  88   // This code can be called during start-up, before the classLoader's classLoader data got
  89   // created.  So, call register_loader() to make sure the classLoader data gets created.
  90   ClassLoaderData *loader_cld = SystemDictionary::register_loader(h_loader, CHECK_NULL);
  91   return loader_cld->modules();
  92 }
  93 
  94 static PackageEntryTable* get_package_entry_table(Handle h_loader, TRAPS) {
  95   // This code can be called during start-up, before the classLoader's classLoader data got
  96   // created.  So, call register_loader() to make sure the classLoader data gets created.
  97   ClassLoaderData *loader_cld = SystemDictionary::register_loader(h_loader, CHECK_NULL);
  98   return loader_cld->packages();
  99 }
 100 
 101 static ModuleEntry* get_module_entry(jobject module, TRAPS) {
 102   Handle module_h(THREAD, JNIHandles::resolve(module));
 103   if (!java_lang_Module::is_instance(module_h())) {
 104     THROW_MSG_NULL(vmSymbols::java_lang_IllegalArgumentException(),
 105                    "module is not an instance of type java.lang.Module");
 106   }
 107   return java_lang_Module::module_entry(module_h(), CHECK_NULL);
 108 }
 109 
 110 static PackageEntry* get_package_entry(ModuleEntry* module_entry, const char* package_name, TRAPS) {
 111   ResourceMark rm(THREAD);
 112   if (package_name == NULL) return NULL;
 113   TempNewSymbol pkg_symbol = SymbolTable::new_symbol(package_name, CHECK_NULL);
 114   PackageEntryTable* package_entry_table = module_entry->loader_data()->packages();
 115   assert(package_entry_table != NULL, "Unexpected null package entry table");
 116   return package_entry_table->lookup_only(pkg_symbol);
 117 }
 118 
 119 static PackageEntry* get_package_entry_by_name(Symbol* package,
 120                                                Handle h_loader,
 121                                                TRAPS) {
 122   if (package != NULL) {
 123     ResourceMark rm(THREAD);
 124     if (Modules::verify_package_name(package->as_C_string())) {
 125       PackageEntryTable* const package_entry_table =
 126         get_package_entry_table(h_loader, CHECK_NULL);
 127       assert(package_entry_table != NULL, "Unexpected null package entry table");
 128       return package_entry_table->lookup_only(package);
 129     }
 130   }
 131   return NULL;
 132 }
 133 
 134 bool Modules::is_package_defined(Symbol* package, Handle h_loader, TRAPS) {
 135   PackageEntry* res = get_package_entry_by_name(package, h_loader, CHECK_false);
 136   return res != NULL;
 137 }
 138 
 139 static void define_javabase_module(jobject module, jstring version,
 140                                    jstring location, const char* const* packages,
 141                                    jsize num_packages, TRAPS) {
 142   ResourceMark rm(THREAD);
 143 
 144   Handle module_handle(THREAD, JNIHandles::resolve(module));
 145 
 146   // Obtain java.base's module version
 147   const char* module_version = get_module_version(version);
 148   TempNewSymbol version_symbol;
 149   if (module_version != NULL) {
 150     version_symbol = SymbolTable::new_symbol(module_version, CHECK);
 151   } else {
 152     version_symbol = NULL;
 153   }
 154 
 155   // Obtain java.base's location
 156   const char* module_location = NULL;
 157   TempNewSymbol location_symbol = NULL;
 158   if (location != NULL) {
 159     module_location =
 160       java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(location));
 161     if (module_location != NULL) {
 162       location_symbol = SymbolTable::new_symbol(module_location, CHECK);
 163     }
 164   }
 165 
 166 
 167   // Check that the packages are syntactically ok.
 168   GrowableArray<Symbol*>* pkg_list = new GrowableArray<Symbol*>(num_packages);
 169   for (int x = 0; x < num_packages; x++) {
 170     const char *package_name = packages[x];
 171     if (!Modules::verify_package_name(package_name)) {
 172       THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 173                 err_msg("Invalid package name: %s for module: " JAVA_BASE_NAME, package_name));
 174     }
 175     Symbol* pkg_symbol = SymbolTable::new_symbol(package_name, CHECK);
 176     pkg_list->append(pkg_symbol);
 177   }
 178 
 179   // Validate java_base's loader is the boot loader.
 180   oop loader = java_lang_Module::loader(module_handle());
 181   if (loader != NULL) {
 182     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 183               "Class loader must be the boot class loader");
 184   }
 185   Handle h_loader(THREAD, loader);
 186 
 187   // Ensure the boot loader's PackageEntryTable has been created
 188   PackageEntryTable* package_table = get_package_entry_table(h_loader, CHECK);
 189   assert(pkg_list->length() == 0 || package_table != NULL, "Bad package_table");
 190 
 191   // Ensure java.base's ModuleEntry has been created
 192   assert(ModuleEntryTable::javabase_moduleEntry() != NULL, "No ModuleEntry for " JAVA_BASE_NAME);
 193 
 194   bool duplicate_javabase = false;
 195   {
 196     MutexLocker m1(Module_lock, THREAD);
 197 
 198     if (ModuleEntryTable::javabase_defined()) {
 199       duplicate_javabase = true;
 200     } else {
 201 
 202       // Verify that all java.base packages created during bootstrapping are in
 203       // pkg_list.  If any are not in pkg_list, than a non-java.base class was
 204       // loaded erroneously pre java.base module definition.
 205       package_table->verify_javabase_packages(pkg_list);
 206 
 207       // loop through and add any new packages for java.base
 208       PackageEntry* pkg;
 209       for (int x = 0; x < pkg_list->length(); x++) {
 210         // Some of java.base's packages were added early in bootstrapping, ignore duplicates.
 211         if (package_table->lookup_only(pkg_list->at(x)) == NULL) {
 212           pkg = package_table->locked_create_entry_or_null(pkg_list->at(x), ModuleEntryTable::javabase_moduleEntry());
 213           assert(pkg != NULL, "Unable to create a " JAVA_BASE_NAME " package entry");
 214         }
 215         // Unable to have a GrowableArray of TempNewSymbol.  Must decrement the refcount of
 216         // the Symbol* that was created above for each package. The refcount was incremented
 217         // by SymbolTable::new_symbol and as well by the PackageEntry creation.
 218         pkg_list->at(x)->decrement_refcount();
 219       }
 220 
 221       // Finish defining java.base's ModuleEntry
 222       ModuleEntryTable::finalize_javabase(module_handle, version_symbol, location_symbol);
 223     }
 224   }
 225   if (duplicate_javabase) {
 226     THROW_MSG(vmSymbols::java_lang_InternalError(),
 227               "Module " JAVA_BASE_NAME " is already defined");
 228   }
 229 
 230   // Only the thread that actually defined the base module will get here,
 231   // so no locking is needed.
 232 
 233   // Patch any previously loaded class's module field with java.base's java.lang.Module.
 234   ModuleEntryTable::patch_javabase_entries(module_handle);
 235 
 236   log_info(module, load)(JAVA_BASE_NAME " location: %s",
 237                          module_location != NULL ? module_location : "NULL");
 238   log_debug(module)("define_javabase_module(): Definition of module: "
 239                     JAVA_BASE_NAME ", version: %s, location: %s, package #: %d",
 240                     module_version != NULL ? module_version : "NULL",
 241                     module_location != NULL ? module_location : "NULL",
 242                     pkg_list->length());
 243 
 244   // packages defined to java.base
 245   if (log_is_enabled(Trace, module)) {
 246     for (int x = 0; x < pkg_list->length(); x++) {
 247       log_trace(module)("define_javabase_module(): creation of package %s for module " JAVA_BASE_NAME,
 248                         (pkg_list->at(x))->as_C_string());
 249     }
 250   }
 251 }
 252 
 253 // Caller needs ResourceMark.
 254 void throw_dup_pkg_exception(const char* module_name, PackageEntry* package, TRAPS) {
 255   const char* package_name = package->name()->as_C_string();
 256   if (package->module()->is_named()) {
 257     THROW_MSG(vmSymbols::java_lang_IllegalStateException(),
 258       err_msg("Package %s for module %s is already in another module, %s, defined to the class loader",
 259               package_name, module_name, package->module()->name()->as_C_string()));
 260   } else {
 261     THROW_MSG(vmSymbols::java_lang_IllegalStateException(),
 262       err_msg("Package %s for module %s is already in the unnamed module defined to the class loader",
 263               package_name, module_name));
 264   }
 265 }
 266 
 267 void Modules::define_module(jobject module, jboolean is_open, jstring version,
 268                             jstring location, const char* const* packages,
 269                             jsize num_packages, TRAPS) {
 270   ResourceMark rm(THREAD);
 271 
 272   if (module == NULL) {
 273     THROW_MSG(vmSymbols::java_lang_NullPointerException(), "Null module object");
 274   }
 275 
 276   if (num_packages < 0) {
 277     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 278               "num_packages must be >= 0");
 279   }
 280 
 281   if (packages == NULL && num_packages > 0) {
 282     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 283               "num_packages should be zero if packages is null");
 284   }
 285 
 286   Handle module_handle(THREAD, JNIHandles::resolve(module));
 287   if (!java_lang_Module::is_instance(module_handle())) {
 288     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 289               "module is not an instance of type java.lang.Module");
 290   }
 291 
 292   char* module_name = get_module_name(module_handle(), CHECK);
 293   if (module_name == NULL) {
 294     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 295               "Module name cannot be null");
 296   }
 297 
 298   // Special handling of java.base definition
 299   if (strcmp(module_name, JAVA_BASE_NAME) == 0) {
 300     assert(is_open == JNI_FALSE, "java.base module cannot be open");
 301     define_javabase_module(module, version, location, packages, num_packages, CHECK);
 302     return;
 303   }
 304 
 305   const char* module_version = get_module_version(version);
 306 
 307   oop loader = java_lang_Module::loader(module_handle());
 308   // Make sure loader is not the jdk.internal.reflect.DelegatingClassLoader.
 309   if (loader != java_lang_ClassLoader::non_reflection_class_loader(loader)) {
 310     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 311               "Class loader is an invalid delegating class loader");
 312   }
 313   Handle h_loader = Handle(THREAD, loader);
 314 
 315   // Check that the list of packages has no duplicates and that the
 316   // packages are syntactically ok.
 317   GrowableArray<Symbol*>* pkg_list = new GrowableArray<Symbol*>(num_packages);
 318   for (int x = 0; x < num_packages; x++) {
 319     const char* package_name = packages[x];
 320     if (!verify_package_name(package_name)) {
 321       THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 322                 err_msg("Invalid package name: %s for module: %s",
 323                         package_name, module_name));
 324     }
 325 
 326     // Only modules defined to either the boot or platform class loader, can define a "java/" package.
 327     if (!h_loader.is_null() &&
 328         !SystemDictionary::is_platform_class_loader(h_loader()) &&
 329         (strncmp(package_name, JAVAPKG, JAVAPKG_LEN) == 0 &&
 330           (package_name[JAVAPKG_LEN] == '/' || package_name[JAVAPKG_LEN] == '\0'))) {
 331       const char* class_loader_name = SystemDictionary::loader_name(h_loader());
 332       size_t pkg_len = strlen(package_name);
 333       char* pkg_name = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, pkg_len);
 334       strncpy(pkg_name, package_name, pkg_len);
 335       StringUtils::replace_no_expand(pkg_name, "/", ".");
 336       const char* msg_text1 = "Class loader (instance of): ";
 337       const char* msg_text2 = " tried to define prohibited package name: ";
 338       size_t len = strlen(msg_text1) + strlen(class_loader_name) + strlen(msg_text2) + pkg_len + 1;
 339       char* message = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, len);
 340       jio_snprintf(message, len, "%s%s%s%s", msg_text1, class_loader_name, msg_text2, pkg_name);
 341       THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), message);
 342     }
 343 
 344     Symbol* pkg_symbol = SymbolTable::new_symbol(package_name, CHECK);
 345     pkg_list->append(pkg_symbol);
 346   }
 347 
 348   ModuleEntryTable* module_table = get_module_entry_table(h_loader, CHECK);
 349   assert(module_table != NULL, "module entry table shouldn't be null");
 350 
 351   // Create symbol* entry for module name.
 352   TempNewSymbol module_symbol = SymbolTable::new_symbol(module_name, CHECK);
 353 
 354   bool dupl_modules = false;
 355 
 356   // Create symbol* entry for module version.
 357   TempNewSymbol version_symbol;
 358   if (module_version != NULL) {
 359     version_symbol = SymbolTable::new_symbol(module_version, CHECK);
 360   } else {
 361     version_symbol = NULL;
 362   }
 363 
 364   // Create symbol* entry for module location.
 365   const char* module_location = NULL;
 366   TempNewSymbol location_symbol = NULL;
 367   if (location != NULL) {
 368     module_location =
 369       java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(location));
 370     if (module_location != NULL) {
 371       location_symbol = SymbolTable::new_symbol(module_location, CHECK);
 372     }
 373   }
 374 
 375   ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(h_loader());
 376   assert(loader_data != NULL, "class loader data shouldn't be null");
 377 
 378   PackageEntryTable* package_table = NULL;
 379   PackageEntry* existing_pkg = NULL;
 380   {
 381     MutexLocker ml(Module_lock, THREAD);
 382 
 383     if (num_packages > 0) {
 384       package_table = get_package_entry_table(h_loader, CHECK);
 385       assert(package_table != NULL, "Missing package_table");
 386 
 387       // Check that none of the packages exist in the class loader's package table.
 388       for (int x = 0; x < pkg_list->length(); x++) {
 389         existing_pkg = package_table->lookup_only(pkg_list->at(x));
 390         if (existing_pkg != NULL) {
 391           // This could be because the module was already defined.  If so,
 392           // report that error instead of the package error.
 393           if (module_table->lookup_only(module_symbol) != NULL) {
 394             dupl_modules = true;
 395           }
 396           break;
 397         }
 398       }
 399     }  // if (num_packages > 0)...
 400 
 401     // Add the module and its packages.
 402     if (!dupl_modules && existing_pkg == NULL) {
 403       // Create the entry for this module in the class loader's module entry table.
 404       ModuleEntry* module_entry = module_table->locked_create_entry_or_null(module_handle,
 405                                     (is_open == JNI_TRUE), module_symbol,
 406                                     version_symbol, location_symbol, loader_data);
 407 
 408       if (module_entry == NULL) {
 409         dupl_modules = true;
 410       } else {
 411         // Add the packages.
 412         assert(pkg_list->length() == 0 || package_table != NULL, "Bad package table");
 413         PackageEntry* pkg;
 414         for (int y = 0; y < pkg_list->length(); y++) {
 415           pkg = package_table->locked_create_entry_or_null(pkg_list->at(y), module_entry);
 416           assert(pkg != NULL, "Unable to create a module's package entry");
 417 
 418           // Unable to have a GrowableArray of TempNewSymbol.  Must decrement the refcount of
 419           // the Symbol* that was created above for each package. The refcount was incremented
 420           // by SymbolTable::new_symbol and as well by the PackageEntry creation.
 421           pkg_list->at(y)->decrement_refcount();
 422         }
 423 
 424         // Store pointer to ModuleEntry record in java.lang.Module object.
 425         java_lang_Module::set_module_entry(module_handle(), module_entry);
 426       }
 427     }
 428   }  // Release the lock
 429 
 430   // any errors ?
 431   if (dupl_modules) {
 432      THROW_MSG(vmSymbols::java_lang_IllegalStateException(),
 433                err_msg("Module %s is already defined", module_name));
 434   } else if (existing_pkg != NULL) {
 435       throw_dup_pkg_exception(module_name, existing_pkg, CHECK);
 436   }
 437 
 438   log_info(module, load)("%s location: %s", module_name,
 439                          module_location != NULL ? module_location : "NULL");
 440   LogTarget(Debug, module) lt;
 441   if (lt.is_enabled()) {
 442     LogStream ls(lt);
 443     ls.print("define_module(): creation of module: %s, version: %s, location: %s, ",
 444                  module_name, module_version != NULL ? module_version : "NULL",
 445                  module_location != NULL ? module_location : "NULL");
 446     loader_data->print_value_on(&ls);
 447     ls.print_cr(", package #: %d", pkg_list->length());
 448     for (int y = 0; y < pkg_list->length(); y++) {
 449       log_trace(module)("define_module(): creation of package %s for module %s",
 450                         (pkg_list->at(y))->as_C_string(), module_name);
 451     }
 452   }
 453 
 454   // If the module is defined to the boot loader and an exploded build is being
 455   // used, prepend <java.home>/modules/modules_name to the system boot class path.
 456   if (loader == NULL && !ClassLoader::has_jrt_entry()) {
 457     ClassLoader::add_to_exploded_build_list(module_symbol, CHECK);
 458   }
 459 }
 460 
 461 void Modules::set_bootloader_unnamed_module(jobject module, TRAPS) {
 462   ResourceMark rm(THREAD);
 463 
 464   if (module == NULL) {
 465     THROW_MSG(vmSymbols::java_lang_NullPointerException(), "Null module object");
 466   }
 467   Handle module_handle(THREAD, JNIHandles::resolve(module));
 468   if (!java_lang_Module::is_instance(module_handle())) {
 469     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 470               "module is not an instance of type java.lang.Module");
 471   }
 472 
 473   // Ensure that this is an unnamed module
 474   oop name = java_lang_Module::name(module_handle());
 475   if (name != NULL) {
 476     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 477               "boot loader's unnamed module's java.lang.Module has a name");
 478   }
 479 
 480   // Validate java_base's loader is the boot loader.
 481   oop loader = java_lang_Module::loader(module_handle());
 482   if (loader != NULL) {
 483     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 484               "Class loader must be the boot class loader");
 485   }
 486   Handle h_loader(THREAD, loader);
 487 
 488   log_debug(module)("set_bootloader_unnamed_module(): recording unnamed module for boot loader");
 489 
 490   // Set java.lang.Module for the boot loader's unnamed module
 491   ClassLoaderData* boot_loader_data = ClassLoaderData::the_null_class_loader_data();
 492   ModuleEntry* unnamed_module = boot_loader_data->unnamed_module();
 493   assert(unnamed_module != NULL, "boot loader's unnamed ModuleEntry not defined");
 494   unnamed_module->set_module(boot_loader_data->add_handle(module_handle));
 495   // Store pointer to the ModuleEntry in the unnamed module's java.lang.Module object.
 496   java_lang_Module::set_module_entry(module_handle(), unnamed_module);
 497 }
 498 
 499 void Modules::add_module_exports(jobject from_module, const char* package_name, jobject to_module, TRAPS) {
 500   if (package_name == NULL) {
 501     THROW_MSG(vmSymbols::java_lang_NullPointerException(),
 502               "package is null");
 503   }
 504   if (from_module == NULL) {
 505     THROW_MSG(vmSymbols::java_lang_NullPointerException(),
 506               "from_module is null");
 507   }
 508   ModuleEntry* from_module_entry = get_module_entry(from_module, CHECK);
 509   if (from_module_entry == NULL) {
 510     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 511               "from_module cannot be found");
 512   }
 513 
 514   // All packages in unnamed and open modules are exported by default.
 515   if (!from_module_entry->is_named() || from_module_entry->is_open()) return;
 516 
 517   ModuleEntry* to_module_entry;
 518   if (to_module == NULL) {
 519     to_module_entry = NULL;  // It's an unqualified export.
 520   } else {
 521     to_module_entry = get_module_entry(to_module, CHECK);
 522     if (to_module_entry == NULL) {
 523       THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 524                 "to_module is invalid");
 525     }
 526   }
 527 
 528   PackageEntry *package_entry = get_package_entry(from_module_entry, package_name, CHECK);
 529   ResourceMark rm(THREAD);
 530   if (package_entry == NULL) {
 531     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 532               err_msg("Package %s not found in from_module %s",
 533                       package_name != NULL ? package_name : "",
 534                       from_module_entry->name()->as_C_string()));
 535   }
 536   if (package_entry->module() != from_module_entry) {
 537     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 538               err_msg("Package: %s found in module %s, not in from_module: %s",
 539                       package_entry->name()->as_C_string(),
 540                       package_entry->module()->name()->as_C_string(),
 541                       from_module_entry->name()->as_C_string()));
 542   }
 543 
 544   log_debug(module)("add_module_exports(): package %s in module %s is exported to module %s",
 545                     package_entry->name()->as_C_string(),
 546                     from_module_entry->name()->as_C_string(),
 547                     to_module_entry == NULL ? "NULL" :
 548                       to_module_entry->is_named() ?
 549                         to_module_entry->name()->as_C_string() : UNNAMED_MODULE);
 550 
 551   // Do nothing if modules are the same.
 552   if (from_module_entry != to_module_entry) {
 553     package_entry->set_exported(to_module_entry);
 554   }
 555 }
 556 
 557 
 558 void Modules::add_module_exports_qualified(jobject from_module, const char* package,
 559                                            jobject to_module, TRAPS) {
 560   if (to_module == NULL) {
 561     THROW_MSG(vmSymbols::java_lang_NullPointerException(),
 562               "to_module is null");
 563   }
 564   add_module_exports(from_module, package, to_module, CHECK);
 565 }
 566 
 567 void Modules::add_reads_module(jobject from_module, jobject to_module, TRAPS) {
 568   if (from_module == NULL) {
 569     THROW_MSG(vmSymbols::java_lang_NullPointerException(),
 570               "from_module is null");
 571   }
 572 
 573   ModuleEntry* from_module_entry = get_module_entry(from_module, CHECK);
 574   if (from_module_entry == NULL) {
 575     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 576               "from_module is not valid");
 577   }
 578 
 579   ModuleEntry* to_module_entry;
 580   if (to_module != NULL) {
 581     to_module_entry = get_module_entry(to_module, CHECK);
 582     if (to_module_entry == NULL) {
 583       THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 584                 "to_module is invalid");
 585     }
 586   } else {
 587     to_module_entry = NULL;
 588   }
 589 
 590   ResourceMark rm(THREAD);
 591   log_debug(module)("add_reads_module(): Adding read from module %s to module %s",
 592                     from_module_entry->is_named() ?
 593                     from_module_entry->name()->as_C_string() : UNNAMED_MODULE,
 594                     to_module_entry == NULL ? "all unnamed" :
 595                       (to_module_entry->is_named() ?
 596                        to_module_entry->name()->as_C_string() : UNNAMED_MODULE));
 597 
 598   // if modules are the same or if from_module is unnamed then no need to add the read.
 599   if (from_module_entry != to_module_entry && from_module_entry->is_named()) {
 600     from_module_entry->add_read(to_module_entry);
 601   }
 602 }
 603 
 604 // This method is called by JFR and JNI.
 605 jobject Modules::get_module(jclass clazz, TRAPS) {
 606   assert(ModuleEntryTable::javabase_defined(),
 607          "Attempt to call get_module before " JAVA_BASE_NAME " is defined");
 608 
 609   if (clazz == NULL) {
 610     THROW_MSG_(vmSymbols::java_lang_NullPointerException(),
 611                "class is null", JNI_FALSE);
 612   }
 613   oop mirror = JNIHandles::resolve_non_null(clazz);
 614   if (mirror == NULL) {
 615     log_debug(module)("get_module(): no mirror, returning NULL");
 616     return NULL;
 617   }
 618   if (!java_lang_Class::is_instance(mirror)) {
 619     THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),
 620                "Invalid class", JNI_FALSE);
 621   }
 622 
 623   oop module = java_lang_Class::module(mirror);
 624 
 625   assert(module != NULL, "java.lang.Class module field not set");
 626   assert(java_lang_Module::is_instance(module), "module is not an instance of type java.lang.Module");
 627 
 628   LogTarget(Debug,module) lt;
 629   if (lt.is_enabled()) {
 630     ResourceMark rm(THREAD);
 631     LogStream ls(lt);
 632     Klass* klass = java_lang_Class::as_Klass(mirror);
 633     oop module_name = java_lang_Module::name(module);
 634     if (module_name != NULL) {
 635       ls.print("get_module(): module ");
 636       java_lang_String::print(module_name, tty);
 637     } else {
 638       ls.print("get_module(): Unamed Module");
 639     }
 640     if (klass != NULL) {
 641       ls.print_cr(" for class %s", klass->external_name());
 642     } else {
 643       ls.print_cr(" for primitive class");
 644     }
 645   }
 646 
 647   return JNIHandles::make_local(THREAD, module);
 648 }
 649 
 650 jobject Modules::get_named_module(Handle h_loader, const char* package_name, TRAPS) {
 651   assert(ModuleEntryTable::javabase_defined(),
 652          "Attempt to call get_named_module before " JAVA_BASE_NAME " is defined");
 653   assert(h_loader.is_null() || java_lang_ClassLoader::is_subclass(h_loader->klass()),
 654          "Class loader is not a subclass of java.lang.ClassLoader");
 655   assert(package_name != NULL, "the package_name should not be NULL");
 656 
 657   if (strlen(package_name) == 0) {
 658     return NULL;
 659   }
 660   TempNewSymbol package_sym = SymbolTable::new_symbol(package_name, CHECK_NULL);
 661   const PackageEntry* const pkg_entry =
 662     get_package_entry_by_name(package_sym, h_loader, THREAD);
 663   const ModuleEntry* const module_entry = (pkg_entry != NULL ? pkg_entry->module() : NULL);
 664 
 665   if (module_entry != NULL && module_entry->module() != NULL && module_entry->is_named()) {
 666     return JNIHandles::make_local(THREAD, JNIHandles::resolve(module_entry->module()));
 667   }
 668   return NULL;
 669 }
 670 
 671 
 672 // This method is called by JFR and by the above method.
 673 jobject Modules::get_module(Symbol* package_name, Handle h_loader, TRAPS) {
 674   const PackageEntry* const pkg_entry =
 675     get_package_entry_by_name(package_name, h_loader, THREAD);
 676   const ModuleEntry* const module_entry = (pkg_entry != NULL ? pkg_entry->module() : NULL);
 677 
 678   if (module_entry != NULL &&
 679       module_entry->module() != NULL) {
 680     return JNIHandles::make_local(THREAD, JNIHandles::resolve(module_entry->module()));
 681   }
 682 
 683   return NULL;
 684 }
 685 
 686 void Modules::add_module_package(jobject module, const char* package_name, TRAPS) {
 687   ResourceMark rm(THREAD);
 688 
 689   if (module == NULL) {
 690     THROW_MSG(vmSymbols::java_lang_NullPointerException(),
 691               "module is null");
 692   }
 693   if (package_name == NULL) {
 694     THROW_MSG(vmSymbols::java_lang_NullPointerException(),
 695               "package is null");
 696   }
 697   ModuleEntry* module_entry = get_module_entry(module, CHECK);
 698   if (module_entry == NULL) {
 699     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 700               "module is invalid");
 701   }
 702   if (!module_entry->is_named()) {
 703     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 704               "module cannot be an unnamed module");
 705   }
 706   if (!verify_package_name(package_name)) {
 707     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 708               err_msg("Invalid package name: %s", package_name));
 709   }
 710 
 711   ClassLoaderData *loader_data = module_entry->loader_data();
 712 
 713   // Only modules defined to either the boot or platform class loader, can define a "java/" package.
 714   if (!loader_data->is_the_null_class_loader_data() &&
 715       !loader_data->is_platform_class_loader_data() &&
 716       (strncmp(package_name, JAVAPKG, JAVAPKG_LEN) == 0 &&
 717         (package_name[JAVAPKG_LEN] == '/' || package_name[JAVAPKG_LEN] == '\0'))) {
 718     const char* class_loader_name = SystemDictionary::loader_name(loader_data);
 719     size_t pkg_len = strlen(package_name);
 720     char* pkg_name = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, pkg_len);
 721     strncpy(pkg_name, package_name, pkg_len);
 722     StringUtils::replace_no_expand(pkg_name, "/", ".");
 723     const char* msg_text1 = "Class loader (instance of): ";
 724     const char* msg_text2 = " tried to define prohibited package name: ";
 725     size_t len = strlen(msg_text1) + strlen(class_loader_name) + strlen(msg_text2) + pkg_len + 1;
 726     char* message = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, len);
 727     jio_snprintf(message, len, "%s%s%s%s", msg_text1, class_loader_name, msg_text2, pkg_name);
 728     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), message);
 729   }
 730 
 731   log_debug(module)("add_module_package(): Adding package %s to module %s",
 732                     package_name, module_entry->name()->as_C_string());
 733 
 734   TempNewSymbol pkg_symbol = SymbolTable::new_symbol(package_name, CHECK);
 735   PackageEntryTable* package_table = loader_data->packages();
 736   assert(package_table != NULL, "Missing package_table");
 737 
 738   PackageEntry* existing_pkg = NULL;
 739   {
 740     MutexLocker ml(Module_lock, THREAD);
 741 
 742     // Check that the package does not exist in the class loader's package table.
 743     existing_pkg = package_table->lookup_only(pkg_symbol);
 744     if (existing_pkg == NULL) {
 745       PackageEntry* pkg = package_table->locked_create_entry_or_null(pkg_symbol, module_entry);
 746       assert(pkg != NULL, "Unable to create a module's package entry");
 747     }
 748   }
 749   if (existing_pkg != NULL) {
 750     throw_dup_pkg_exception(module_entry->name()->as_C_string(), existing_pkg, CHECK);
 751   }
 752 }
 753 
 754 // Export package in module to all unnamed modules.
 755 void Modules::add_module_exports_to_all_unnamed(jobject module, const char* package_name, TRAPS) {
 756   if (module == NULL) {
 757     THROW_MSG(vmSymbols::java_lang_NullPointerException(),
 758               "module is null");
 759   }
 760   if (package_name == NULL) {
 761     THROW_MSG(vmSymbols::java_lang_NullPointerException(),
 762               "package is null");
 763   }
 764   ModuleEntry* module_entry = get_module_entry(module, CHECK);
 765   if (module_entry == NULL) {
 766     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 767               "module is invalid");
 768   }
 769 
 770   if (module_entry->is_named()) { // No-op for unnamed module.
 771     PackageEntry *package_entry = get_package_entry(module_entry, package_name, CHECK);
 772     ResourceMark rm(THREAD);
 773     if (package_entry == NULL) {
 774       THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 775                 err_msg("Package %s not found in module %s",
 776                         package_name != NULL ? package_name : "",
 777                         module_entry->name()->as_C_string()));
 778     }
 779     if (package_entry->module() != module_entry) {
 780       THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 781                 err_msg("Package: %s found in module %s, not in module: %s",
 782                         package_entry->name()->as_C_string(),
 783                         package_entry->module()->name()->as_C_string(),
 784                         module_entry->name()->as_C_string()));
 785     }
 786 
 787     log_debug(module)("add_module_exports_to_all_unnamed(): package %s in module"
 788                       " %s is exported to all unnamed modules",
 789                        package_entry->name()->as_C_string(),
 790                        module_entry->name()->as_C_string());
 791 
 792     // Mark package as exported to all unnamed modules.
 793     package_entry->set_is_exported_allUnnamed();
 794   }
 795 }