1 /*
   2  * Copyright (c) 1997, 2025, 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 "cds/aotClassLocation.hpp"
  26 #include "cds/cds_globals.hpp"
  27 #include "cds/cdsConfig.hpp"
  28 #include "cds/heapShared.hpp"
  29 #include "classfile/classFileStream.hpp"
  30 #include "classfile/classLoader.inline.hpp"
  31 #include "classfile/classLoaderData.inline.hpp"
  32 #include "classfile/classLoaderExt.hpp"
  33 #include "classfile/classLoadInfo.hpp"
  34 #include "classfile/javaClasses.hpp"
  35 #include "classfile/klassFactory.hpp"
  36 #include "classfile/moduleEntry.hpp"
  37 #include "classfile/modules.hpp"
  38 #include "classfile/packageEntry.hpp"
  39 #include "classfile/symbolTable.hpp"
  40 #include "classfile/systemDictionary.hpp"
  41 #include "classfile/systemDictionaryShared.hpp"
  42 #include "classfile/vmClasses.hpp"
  43 #include "classfile/vmSymbols.hpp"
  44 #include "compiler/compileBroker.hpp"
  45 #include "interpreter/bytecodeStream.hpp"
  46 #include "interpreter/oopMapCache.hpp"
  47 #include "jimage.hpp"
  48 #include "jvm.h"
  49 #include "logging/log.hpp"
  50 #include "logging/logStream.hpp"
  51 #include "logging/logTag.hpp"
  52 #include "memory/allocation.inline.hpp"
  53 #include "memory/oopFactory.hpp"
  54 #include "memory/resourceArea.hpp"
  55 #include "memory/universe.hpp"
  56 #include "oops/instanceKlass.hpp"
  57 #include "oops/instanceRefKlass.hpp"
  58 #include "oops/klass.inline.hpp"
  59 #include "oops/method.inline.hpp"
  60 #include "oops/objArrayOop.inline.hpp"
  61 #include "oops/oop.inline.hpp"
  62 #include "oops/symbol.hpp"
  63 #include "prims/jvm_misc.hpp"
  64 #include "runtime/arguments.hpp"
  65 #include "runtime/handles.inline.hpp"
  66 #include "runtime/init.hpp"
  67 #include "runtime/interfaceSupport.inline.hpp"
  68 #include "runtime/java.hpp"
  69 #include "runtime/javaCalls.hpp"
  70 #include "runtime/os.hpp"
  71 #include "runtime/perfData.hpp"
  72 #include "runtime/timer.hpp"
  73 #include "runtime/vm_version.hpp"
  74 #include "services/management.hpp"
  75 #include "services/threadService.hpp"
  76 #include "utilities/checkedCast.hpp"
  77 #include "utilities/classpathStream.hpp"
  78 #include "utilities/events.hpp"
  79 #include "utilities/macros.hpp"
  80 #include "utilities/ostream.hpp"
  81 #include "utilities/utf8.hpp"
  82 
  83 #include <stdlib.h>
  84 #include <ctype.h>
  85 
  86 // Entry point in java.dll for path canonicalization
  87 
  88 typedef int (*canonicalize_fn_t)(const char *orig, char *out, int len);
  89 
  90 static canonicalize_fn_t CanonicalizeEntry  = nullptr;
  91 
  92 // Entry points for jimage.dll for loading jimage file entries
  93 
  94 static JImageOpen_t                    JImageOpen             = nullptr;
  95 static JImageClose_t                   JImageClose            = nullptr;
  96 static JImageFindResource_t            JImageFindResource     = nullptr;
  97 static JImageGetResource_t             JImageGetResource      = nullptr;
  98 
  99 // JimageFile pointer, or null if exploded JDK build.
 100 static JImageFile*                     JImage_file            = nullptr;
 101 
 102 // Globals
 103 
 104 PerfCounter*    ClassLoader::_perf_accumulated_time = nullptr;
 105 PerfCounter*    ClassLoader::_perf_classes_inited = nullptr;
 106 PerfCounter*    ClassLoader::_perf_class_init_time = nullptr;
 107 PerfCounter*    ClassLoader::_perf_class_init_selftime = nullptr;
 108 PerfCounter*    ClassLoader::_perf_classes_verified = nullptr;
 109 PerfCounter*    ClassLoader::_perf_class_verify_time = nullptr;
 110 PerfCounter*    ClassLoader::_perf_class_verify_selftime = nullptr;
 111 PerfCounter*    ClassLoader::_perf_classes_linked = nullptr;
 112 PerfCounter*    ClassLoader::_perf_class_link_time = nullptr;
 113 PerfCounter*    ClassLoader::_perf_class_link_selftime = nullptr;
 114 PerfCounter*    ClassLoader::_perf_shared_classload_time = nullptr;
 115 PerfCounter*    ClassLoader::_perf_sys_classload_time = nullptr;
 116 PerfCounter*    ClassLoader::_perf_app_classload_time = nullptr;
 117 PerfCounter*    ClassLoader::_perf_app_classload_selftime = nullptr;
 118 PerfCounter*    ClassLoader::_perf_app_classload_count = nullptr;
 119 PerfCounter*    ClassLoader::_perf_define_appclasses = nullptr;
 120 PerfCounter*    ClassLoader::_perf_define_appclass_time = nullptr;
 121 PerfCounter*    ClassLoader::_perf_define_appclass_selftime = nullptr;
 122 PerfCounter*    ClassLoader::_perf_app_classfile_bytes_read = nullptr;
 123 PerfCounter*    ClassLoader::_perf_sys_classfile_bytes_read = nullptr;
 124 PerfCounter*    ClassLoader::_perf_ik_link_methods_time = nullptr;
 125 PerfCounter*    ClassLoader::_perf_method_adapters_time = nullptr;
 126 PerfCounter*    ClassLoader::_perf_ik_link_methods_count = nullptr;
 127 PerfCounter*    ClassLoader::_perf_method_adapters_count = nullptr;
 128 PerfCounter*    ClassLoader::_unsafe_defineClassCallCounter = nullptr;
 129 PerfCounter*    ClassLoader::_perf_secondary_hash_time = nullptr;
 130 
 131 PerfCounter*    ClassLoader::_perf_resolve_indy_time = nullptr;
 132 PerfCounter*    ClassLoader::_perf_resolve_invokehandle_time = nullptr;
 133 PerfCounter*    ClassLoader::_perf_resolve_mh_time = nullptr;
 134 PerfCounter*    ClassLoader::_perf_resolve_mt_time = nullptr;
 135 
 136 PerfCounter*    ClassLoader::_perf_resolve_indy_count = nullptr;
 137 PerfCounter*    ClassLoader::_perf_resolve_invokehandle_count = nullptr;
 138 PerfCounter*    ClassLoader::_perf_resolve_mh_count = nullptr;
 139 PerfCounter*    ClassLoader::_perf_resolve_mt_count = nullptr;
 140 
 141 void ClassLoader::print_counters(outputStream *st) {
 142   st->print_cr("ClassLoader:");
 143   st->print_cr("  clinit:               " JLONG_FORMAT "ms / " JLONG_FORMAT " events", ClassLoader::class_init_time_ms(), ClassLoader::class_init_count());
 144   st->print_cr("  link methods:         " JLONG_FORMAT "ms / " JLONG_FORMAT " events", Management::ticks_to_ms(_perf_ik_link_methods_time->get_value())   , _perf_ik_link_methods_count->get_value());
 145   st->print_cr("  method adapters:      " JLONG_FORMAT "ms / " JLONG_FORMAT " events", Management::ticks_to_ms(_perf_method_adapters_time->get_value())   , _perf_method_adapters_count->get_value());
 146   st->print_cr("  resolve...");
 147   st->print_cr("    invokedynamic:   " JLONG_FORMAT "ms / " JLONG_FORMAT " events", Management::ticks_to_ms(_perf_resolve_indy_time->get_value())         , _perf_resolve_indy_count->get_value());
 148   st->print_cr("    invokehandle:    " JLONG_FORMAT "ms / " JLONG_FORMAT " events", Management::ticks_to_ms(_perf_resolve_invokehandle_time->get_value()) , _perf_resolve_invokehandle_count->get_value());
 149   st->print_cr("    CP_MethodHandle: " JLONG_FORMAT "ms / " JLONG_FORMAT " events", Management::ticks_to_ms(_perf_resolve_mh_time->get_value())           , _perf_resolve_mh_count->get_value());
 150   st->print_cr("    CP_MethodType:   " JLONG_FORMAT "ms / " JLONG_FORMAT " events", Management::ticks_to_ms(_perf_resolve_mt_time->get_value())           , _perf_resolve_mt_count->get_value());
 151   st->cr();
 152 }
 153 
 154 GrowableArray<ModuleClassPathList*>* ClassLoader::_patch_mod_entries = nullptr;
 155 GrowableArray<ModuleClassPathList*>* ClassLoader::_exploded_entries = nullptr;
 156 ClassPathEntry* ClassLoader::_jrt_entry = nullptr;
 157 
 158 ClassPathEntry* volatile ClassLoader::_first_append_entry_list = nullptr;
 159 ClassPathEntry* volatile ClassLoader::_last_append_entry  = nullptr;
 160 
 161 // helper routines
 162 #if INCLUDE_CDS
 163 static bool string_starts_with(const char* str, const char* str_to_find) {
 164   size_t str_len = strlen(str);
 165   size_t str_to_find_len = strlen(str_to_find);
 166   if (str_to_find_len > str_len) {
 167     return false;
 168   }
 169   return (strncmp(str, str_to_find, str_to_find_len) == 0);
 170 }
 171 #endif
 172 
 173 static const char* get_jimage_version_string() {
 174   static char version_string[10] = "";
 175   if (version_string[0] == '\0') {
 176     jio_snprintf(version_string, sizeof(version_string), "%d.%d",
 177                  VM_Version::vm_major_version(), VM_Version::vm_minor_version());
 178   }
 179   return (const char*)version_string;
 180 }
 181 
 182 bool ClassLoader::string_ends_with(const char* str, const char* str_to_find) {
 183   size_t str_len = strlen(str);
 184   size_t str_to_find_len = strlen(str_to_find);
 185   if (str_to_find_len > str_len) {
 186     return false;
 187   }
 188   return (strncmp(str + (str_len - str_to_find_len), str_to_find, str_to_find_len) == 0);
 189 }
 190 
 191 // Used to obtain the package name from a fully qualified class name.
 192 Symbol* ClassLoader::package_from_class_name(const Symbol* name, bool* bad_class_name) {
 193   if (name == nullptr) {
 194     if (bad_class_name != nullptr) {
 195       *bad_class_name = true;
 196     }
 197     return nullptr;
 198   }
 199 
 200   int utf_len = name->utf8_length();
 201   const jbyte* base = (const jbyte*)name->base();
 202   const jbyte* start = base;
 203   const jbyte* end = UTF8::strrchr(start, utf_len, JVM_SIGNATURE_SLASH);
 204   if (end == nullptr) {
 205     return nullptr;
 206   }
 207   // Skip over '['s
 208   if (*start == JVM_SIGNATURE_ARRAY) {
 209     do {
 210       start++;
 211     } while (start < end && *start == JVM_SIGNATURE_ARRAY);
 212 
 213     // Fully qualified class names should not contain a 'L'.
 214     // Set bad_class_name to true to indicate that the package name
 215     // could not be obtained due to an error condition.
 216     // In this situation, is_same_class_package returns false.
 217     if (*start == JVM_SIGNATURE_CLASS) {
 218       if (bad_class_name != nullptr) {
 219         *bad_class_name = true;
 220       }
 221       return nullptr;
 222     }
 223   }
 224   // A class name could have just the slash character in the name,
 225   // in which case start > end
 226   if (start >= end) {
 227     // No package name
 228     if (bad_class_name != nullptr) {
 229       *bad_class_name = true;
 230     }
 231     return nullptr;
 232   }
 233   return SymbolTable::new_symbol(name, pointer_delta_as_int(start, base), pointer_delta_as_int(end, base));
 234 }
 235 
 236 // Given a fully qualified package name, find its defining package in the class loader's
 237 // package entry table.
 238 PackageEntry* ClassLoader::get_package_entry(Symbol* pkg_name, ClassLoaderData* loader_data) {
 239   if (pkg_name == nullptr) {
 240     return nullptr;
 241   }
 242   PackageEntryTable* pkgEntryTable = loader_data->packages();
 243   return pkgEntryTable->lookup_only(pkg_name);
 244 }
 245 
 246 const char* ClassPathEntry::copy_path(const char* path) {
 247   char* copy = NEW_C_HEAP_ARRAY(char, strlen(path)+1, mtClass);
 248   strcpy(copy, path);
 249   return copy;
 250 }
 251 
 252 ClassPathDirEntry::~ClassPathDirEntry() {
 253   FREE_C_HEAP_ARRAY(char, _dir);
 254 }
 255 
 256 ClassFileStream* ClassPathDirEntry::open_stream(JavaThread* current, const char* name) {
 257   // construct full path name
 258   assert((_dir != nullptr) && (name != nullptr), "sanity");
 259   size_t path_len = strlen(_dir) + strlen(name) + strlen(os::file_separator()) + 1;
 260   char* path = NEW_RESOURCE_ARRAY_IN_THREAD(current, char, path_len);
 261   int len = jio_snprintf(path, path_len, "%s%s%s", _dir, os::file_separator(), name);
 262   assert(len == (int)(path_len - 1), "sanity");
 263   // check if file exists
 264   struct stat st;
 265   if (os::stat(path, &st) == 0) {
 266     // found file, open it
 267     int file_handle = os::open(path, 0, 0);
 268     if (file_handle != -1) {
 269       // read contents into resource array
 270       u1* buffer = NEW_RESOURCE_ARRAY_IN_THREAD(current, u1, st.st_size);
 271       size_t num_read = ::read(file_handle, (char*) buffer, st.st_size);
 272       // close file
 273       ::close(file_handle);
 274       // construct ClassFileStream
 275       if (num_read == (size_t)st.st_size) {
 276         if (UsePerfData) {
 277           ClassLoader::perf_sys_classfile_bytes_read()->inc(num_read);
 278         }
 279 #ifdef ASSERT
 280         // Freeing path is a no-op here as buffer prevents it from being reclaimed. But we keep it for
 281         // debug builds so that we guard against use-after-free bugs.
 282         FREE_RESOURCE_ARRAY_IN_THREAD(current, char, path, path_len);
 283 #endif
 284         // We don't verify the length of the classfile stream fits in an int, but this is the
 285         // bootloader so we have control of this.
 286         // Resource allocated
 287         return new ClassFileStream(buffer,
 288                                    checked_cast<int>(st.st_size),
 289                                    _dir);
 290       }
 291     }
 292   }
 293   FREE_RESOURCE_ARRAY_IN_THREAD(current, char, path, path_len);
 294   return nullptr;
 295 }
 296 
 297 ClassPathZipEntry::ClassPathZipEntry(jzfile* zip, const char* zip_name) : ClassPathEntry() {
 298   _zip = zip;
 299   _zip_name = copy_path(zip_name);
 300 }
 301 
 302 ClassPathZipEntry::~ClassPathZipEntry() {
 303   ZipLibrary::close(_zip);
 304   FREE_C_HEAP_ARRAY(char, _zip_name);
 305 }
 306 
 307 bool ClassPathZipEntry::has_entry(JavaThread* current, const char* name) {
 308   ThreadToNativeFromVM ttn(current);
 309   // check whether zip archive contains name
 310   jint name_len;
 311   jint filesize;
 312   jzentry* entry = ZipLibrary::find_entry(_zip, name, &filesize, &name_len);
 313   if (entry == nullptr) {
 314     return false;
 315   } else {
 316      ZipLibrary::free_entry(_zip, entry);
 317     return true;
 318   }
 319 }
 320 
 321 u1* ClassPathZipEntry::open_entry(JavaThread* current, const char* name, jint* filesize, bool nul_terminate) {
 322   // enable call to C land
 323   ThreadToNativeFromVM ttn(current);
 324   // check whether zip archive contains name
 325   jint name_len;
 326   jzentry* entry = ZipLibrary::find_entry(_zip, name, filesize, &name_len);
 327   if (entry == nullptr) return nullptr;
 328   u1* buffer;
 329   char name_buf[128];
 330   char* filename;
 331   if (name_len < 128) {
 332     filename = name_buf;
 333   } else {
 334     filename = NEW_RESOURCE_ARRAY(char, name_len + 1);
 335   }
 336 
 337   // read contents into resource array
 338   size_t size = (uint32_t)(*filesize);
 339   if (nul_terminate) {
 340     if (sizeof(size) == sizeof(uint32_t) && size == UINT_MAX) {
 341       return nullptr; // 32-bit integer overflow will occur.
 342     }
 343     size++;
 344   }
 345   buffer = NEW_RESOURCE_ARRAY(u1, size);
 346   if (!ZipLibrary::read_entry(_zip, entry, buffer, filename)) {
 347     return nullptr;
 348   }
 349 
 350   // return result
 351   if (nul_terminate) {
 352     buffer[size - 1] = 0;
 353   }
 354   return buffer;
 355 }
 356 
 357 ClassFileStream* ClassPathZipEntry::open_stream(JavaThread* current, const char* name) {
 358   jint filesize;
 359   u1* buffer = open_entry(current, name, &filesize, false);
 360   if (buffer == nullptr) {
 361     return nullptr;
 362   }
 363   if (UsePerfData) {
 364     ClassLoader::perf_sys_classfile_bytes_read()->inc(filesize);
 365   }
 366   // Resource allocated
 367   return new ClassFileStream(buffer,
 368                              filesize,
 369                              _zip_name);
 370 }
 371 
 372 DEBUG_ONLY(ClassPathImageEntry* ClassPathImageEntry::_singleton = nullptr;)
 373 
 374 JImageFile* ClassPathImageEntry::jimage() const {
 375   return JImage_file;
 376 }
 377 
 378 JImageFile* ClassPathImageEntry::jimage_non_null() const {
 379   assert(ClassLoader::has_jrt_entry(), "must be");
 380   assert(jimage() != nullptr, "should have been opened by ClassLoader::lookup_vm_options "
 381                            "and remained throughout normal JVM lifetime");
 382   return jimage();
 383 }
 384 
 385 void ClassPathImageEntry::close_jimage() {
 386   if (jimage() != nullptr) {
 387     (*JImageClose)(jimage());
 388     JImage_file = nullptr;
 389   }
 390 }
 391 
 392 ClassPathImageEntry::ClassPathImageEntry(JImageFile* jimage, const char* name) :
 393   ClassPathEntry() {
 394   guarantee(jimage != nullptr, "jimage file is null");
 395   guarantee(name != nullptr, "jimage file name is null");
 396   assert(_singleton == nullptr, "VM supports only one jimage");
 397   DEBUG_ONLY(_singleton = this);
 398   size_t len = strlen(name) + 1;
 399   _name = copy_path(name);
 400 }
 401 
 402 ClassFileStream* ClassPathImageEntry::open_stream(JavaThread* current, const char* name) {
 403   return open_stream_for_loader(current, name, ClassLoaderData::the_null_class_loader_data());
 404 }
 405 
 406 // For a class in a named module, look it up in the jimage file using this syntax:
 407 //    /<module-name>/<package-name>/<base-class>
 408 //
 409 // Assumptions:
 410 //     1. There are no unnamed modules in the jimage file.
 411 //     2. A package is in at most one module in the jimage file.
 412 //
 413 ClassFileStream* ClassPathImageEntry::open_stream_for_loader(JavaThread* current, const char* name, ClassLoaderData* loader_data) {
 414   jlong size;
 415   JImageLocationRef location = (*JImageFindResource)(jimage_non_null(), "", get_jimage_version_string(), name, &size);
 416 
 417   if (location == 0) {
 418     TempNewSymbol class_name = SymbolTable::new_symbol(name);
 419     TempNewSymbol pkg_name = ClassLoader::package_from_class_name(class_name);
 420 
 421     if (pkg_name != nullptr) {
 422       if (!Universe::is_module_initialized()) {
 423         location = (*JImageFindResource)(jimage_non_null(), JAVA_BASE_NAME, get_jimage_version_string(), name, &size);
 424       } else {
 425         PackageEntry* package_entry = ClassLoader::get_package_entry(pkg_name, loader_data);
 426         if (package_entry != nullptr) {
 427           ResourceMark rm(current);
 428           // Get the module name
 429           ModuleEntry* module = package_entry->module();
 430           assert(module != nullptr, "Boot classLoader package missing module");
 431           assert(module->is_named(), "Boot classLoader package is in unnamed module");
 432           const char* module_name = module->name()->as_C_string();
 433           if (module_name != nullptr) {
 434             location = (*JImageFindResource)(jimage_non_null(), module_name, get_jimage_version_string(), name, &size);
 435           }
 436         }
 437       }
 438     }
 439   }
 440   if (location != 0) {
 441     if (UsePerfData) {
 442       ClassLoader::perf_sys_classfile_bytes_read()->inc(size);
 443     }
 444     char* data = NEW_RESOURCE_ARRAY(char, size);
 445     (*JImageGetResource)(jimage_non_null(), location, data, size);
 446     // Resource allocated
 447     assert(this == (ClassPathImageEntry*)ClassLoader::get_jrt_entry(), "must be");
 448     return new ClassFileStream((u1*)data,
 449                                checked_cast<int>(size),
 450                                _name,
 451                                true); // from_boot_loader_modules_image
 452   }
 453 
 454   return nullptr;
 455 }
 456 
 457 JImageLocationRef ClassLoader::jimage_find_resource(JImageFile* jf,
 458                                                     const char* module_name,
 459                                                     const char* file_name,
 460                                                     jlong &size) {
 461   return ((*JImageFindResource)(jf, module_name, get_jimage_version_string(), file_name, &size));
 462 }
 463 
 464 bool ClassPathImageEntry::is_modules_image() const {
 465   assert(this == _singleton, "VM supports a single jimage");
 466   assert(this == (ClassPathImageEntry*)ClassLoader::get_jrt_entry(), "must be used for jrt entry");
 467   return true;
 468 }
 469 
 470 ModuleClassPathList::ModuleClassPathList(Symbol* module_name) {
 471   _module_name = module_name;
 472   _module_first_entry = nullptr;
 473   _module_last_entry = nullptr;
 474 }
 475 
 476 ModuleClassPathList::~ModuleClassPathList() {
 477   // Clean out each ClassPathEntry on list
 478   ClassPathEntry* e = _module_first_entry;
 479   while (e != nullptr) {
 480     ClassPathEntry* next_entry = e->next();
 481     delete e;
 482     e = next_entry;
 483   }
 484 }
 485 
 486 void ModuleClassPathList::add_to_list(ClassPathEntry* new_entry) {
 487   if (new_entry != nullptr) {
 488     if (_module_last_entry == nullptr) {
 489       _module_first_entry = _module_last_entry = new_entry;
 490     } else {
 491       _module_last_entry->set_next(new_entry);
 492       _module_last_entry = new_entry;
 493     }
 494   }
 495 }
 496 
 497 void ClassLoader::trace_class_path(const char* msg, const char* name) {
 498   LogTarget(Info, class, path) lt;
 499   if (lt.is_enabled()) {
 500     LogStream ls(lt);
 501     if (msg) {
 502       ls.print("%s", msg);
 503     }
 504     if (name) {
 505       if (strlen(name) < 256) {
 506         ls.print("%s", name);
 507       } else {
 508         // For very long paths, we need to print each character separately,
 509         // as print_cr() has a length limit
 510         while (name[0] != '\0') {
 511           ls.print("%c", name[0]);
 512           name++;
 513         }
 514       }
 515     }
 516     ls.cr();
 517   }
 518 }
 519 
 520 void ClassLoader::setup_bootstrap_search_path(JavaThread* current) {
 521   const char* bootcp = Arguments::get_boot_class_path();
 522   assert(bootcp != nullptr, "Boot class path must not be nullptr");
 523   if (PrintSharedArchiveAndExit) {
 524     // Don't print bootcp - this is the bootcp of this current VM process, not necessarily
 525     // the same as the boot classpath of the shared archive.
 526   } else {
 527     trace_class_path("bootstrap loader class path=", bootcp);
 528   }
 529   setup_bootstrap_search_path_impl(current, bootcp);
 530 }
 531 
 532 void ClassLoader::close_jrt_image() {
 533   // Not applicable for exploded builds
 534   if (!ClassLoader::has_jrt_entry()) return;
 535   _jrt_entry->close_jimage();
 536 }
 537 
 538 // Construct the array of module/path pairs as specified to --patch-module
 539 // for the boot loader to search ahead of the jimage, if the class being
 540 // loaded is defined to a module that has been specified to --patch-module.
 541 void ClassLoader::setup_patch_mod_entries() {
 542   JavaThread* current = JavaThread::current();
 543   GrowableArray<ModulePatchPath*>* patch_mod_args = Arguments::get_patch_mod_prefix();
 544   int num_of_entries = patch_mod_args->length();
 545 
 546   // Set up the boot loader's _patch_mod_entries list
 547   _patch_mod_entries = new (mtModule) GrowableArray<ModuleClassPathList*>(num_of_entries, mtModule);
 548 
 549   for (int i = 0; i < num_of_entries; i++) {
 550     const char* module_name = (patch_mod_args->at(i))->module_name();
 551     Symbol* const module_sym = SymbolTable::new_symbol(module_name);
 552     assert(module_sym != nullptr, "Failed to obtain Symbol for module name");
 553     ModuleClassPathList* module_cpl = new ModuleClassPathList(module_sym);
 554 
 555     char* class_path = (patch_mod_args->at(i))->path_string();
 556     ResourceMark rm(current);
 557     ClasspathStream cp_stream(class_path);
 558 
 559     while (cp_stream.has_next()) {
 560       const char* path = cp_stream.get_next();
 561       struct stat st;
 562       if (os::stat(path, &st) == 0) {
 563         // File or directory found
 564         ClassPathEntry* new_entry = create_class_path_entry(current, path, &st);
 565         // If the path specification is valid, enter it into this module's list
 566         if (new_entry != nullptr) {
 567           module_cpl->add_to_list(new_entry);
 568         }
 569       }
 570     }
 571 
 572     // Record the module into the list of --patch-module entries only if
 573     // valid ClassPathEntrys have been created
 574     if (module_cpl->module_first_entry() != nullptr) {
 575       _patch_mod_entries->push(module_cpl);
 576     }
 577   }
 578 }
 579 
 580 // Determine whether the module has been patched via the command-line
 581 // option --patch-module
 582 bool ClassLoader::is_in_patch_mod_entries(Symbol* module_name) {
 583   if (_patch_mod_entries != nullptr && _patch_mod_entries->is_nonempty()) {
 584     int table_len = _patch_mod_entries->length();
 585     for (int i = 0; i < table_len; i++) {
 586       ModuleClassPathList* patch_mod = _patch_mod_entries->at(i);
 587       if (module_name->fast_compare(patch_mod->module_name()) == 0) {
 588         return true;
 589       }
 590     }
 591   }
 592   return false;
 593 }
 594 
 595 // Set up the _jrt_entry if present and boot append path
 596 void ClassLoader::setup_bootstrap_search_path_impl(JavaThread* current, const char *class_path) {
 597   ResourceMark rm(current);
 598   ClasspathStream cp_stream(class_path);
 599   bool set_base_piece = true;
 600 
 601 #if INCLUDE_CDS
 602   if (CDSConfig::is_dumping_archive()) {
 603     if (!Arguments::has_jimage()) {
 604       vm_exit_during_initialization("CDS is not supported in exploded JDK build", nullptr);
 605     }
 606   }
 607 #endif
 608 
 609   while (cp_stream.has_next()) {
 610     const char* path = cp_stream.get_next();
 611 
 612     if (set_base_piece) {
 613       // The first time through the bootstrap_search setup, it must be determined
 614       // what the base or core piece of the boot loader search is.  Either a java runtime
 615       // image is present or this is an exploded module build situation.
 616       assert(string_ends_with(path, MODULES_IMAGE_NAME) || string_ends_with(path, JAVA_BASE_NAME),
 617              "Incorrect boot loader search path, no java runtime image or " JAVA_BASE_NAME " exploded build");
 618       struct stat st;
 619       if (os::stat(path, &st) == 0) {
 620         // Directory found
 621         if (JImage_file != nullptr) {
 622           assert(Arguments::has_jimage(), "sanity check");
 623           const char* canonical_path = get_canonical_path(path, current);
 624           assert(canonical_path != nullptr, "canonical_path issue");
 625 
 626           _jrt_entry = new ClassPathImageEntry(JImage_file, canonical_path);
 627           assert(_jrt_entry != nullptr && _jrt_entry->is_modules_image(), "No java runtime image present");
 628           assert(_jrt_entry->jimage() != nullptr, "No java runtime image");
 629         } // else it's an exploded build.
 630       } else {
 631         // If path does not exist, exit
 632         vm_exit_during_initialization("Unable to establish the boot loader search path", path);
 633       }
 634       set_base_piece = false;
 635     } else {
 636       // Every entry on the boot class path after the initial base piece,
 637       // which is set by os::set_boot_path(), is considered an appended entry.
 638       update_class_path_entry_list(current, path);
 639     }
 640   }
 641 }
 642 
 643 // Gets the exploded path for the named module. The memory for the path
 644 // is allocated on the C heap if `c_heap` is true otherwise in the resource area.
 645 static const char* get_exploded_module_path(const char* module_name, bool c_heap) {
 646   const char *home = Arguments::get_java_home();
 647   const char file_sep = os::file_separator()[0];
 648   // 10 represents the length of "modules" + 2 file separators + \0
 649   size_t len = strlen(home) + strlen(module_name) + 10;
 650   char *path = c_heap ? NEW_C_HEAP_ARRAY(char, len, mtModule) : NEW_RESOURCE_ARRAY(char, len);
 651   jio_snprintf(path, len, "%s%cmodules%c%s", home, file_sep, file_sep, module_name);
 652   return path;
 653 }
 654 
 655 // During an exploded modules build, each module defined to the boot loader
 656 // will be added to the ClassLoader::_exploded_entries array.
 657 void ClassLoader::add_to_exploded_build_list(JavaThread* current, Symbol* module_sym) {
 658   assert(!ClassLoader::has_jrt_entry(), "Exploded build not applicable");
 659   assert(_exploded_entries != nullptr, "_exploded_entries was not initialized");
 660 
 661   // Find the module's symbol
 662   ResourceMark rm(current);
 663   const char *module_name = module_sym->as_C_string();
 664   const char *path = get_exploded_module_path(module_name, false);
 665 
 666   struct stat st;
 667   if (os::stat(path, &st) == 0) {
 668     // Directory found
 669     ClassPathEntry* new_entry = create_class_path_entry(current, path, &st);
 670 
 671     // If the path specification is valid, enter it into this module's list.
 672     // There is no need to check for duplicate modules in the exploded entry list,
 673     // since no two modules with the same name can be defined to the boot loader.
 674     // This is checked at module definition time in Modules::define_module.
 675     if (new_entry != nullptr) {
 676       ModuleClassPathList* module_cpl = new ModuleClassPathList(module_sym);
 677       module_cpl->add_to_list(new_entry);
 678       {
 679         MutexLocker ml(current, Module_lock);
 680         _exploded_entries->push(module_cpl);
 681       }
 682       log_info(class, load)("path: %s", path);
 683     }
 684   }
 685 }
 686 
 687 jzfile* ClassLoader::open_zip_file(const char* canonical_path, char** error_msg, JavaThread* thread) {
 688   // enable call to C land
 689   ThreadToNativeFromVM ttn(thread);
 690   HandleMark hm(thread);
 691   return ZipLibrary::open(canonical_path, error_msg);
 692 }
 693 
 694 ClassPathEntry* ClassLoader::create_class_path_entry(JavaThread* current,
 695                                                      const char *path, const struct stat* st) {
 696   ClassPathEntry* new_entry = nullptr;
 697   if ((st->st_mode & S_IFMT) == S_IFREG) {
 698     ResourceMark rm(current);
 699     // Regular file, should be a zip file
 700     // Canonicalized filename
 701     const char* canonical_path = get_canonical_path(path, current);
 702     if (canonical_path == nullptr) {
 703       return nullptr;
 704     }
 705     char* error_msg = nullptr;
 706     jzfile* zip = open_zip_file(canonical_path, &error_msg, current);
 707     if (zip != nullptr && error_msg == nullptr) {
 708       new_entry = new ClassPathZipEntry(zip, path);
 709     } else {
 710       return nullptr;
 711     }
 712     log_info(class, path)("opened: %s", path);
 713     log_info(class, load)("opened: %s", path);
 714   } else {
 715     // Directory
 716     new_entry = new ClassPathDirEntry(path);
 717     log_info(class, load)("path: %s", path);
 718   }
 719   return new_entry;
 720 }
 721 
 722 
 723 // Create a class path zip entry for a given path (return null if not found
 724 // or zip/JAR file cannot be opened)
 725 ClassPathZipEntry* ClassLoader::create_class_path_zip_entry(const char *path) {
 726   // check for a regular file
 727   struct stat st;
 728   if (os::stat(path, &st) == 0) {
 729     if ((st.st_mode & S_IFMT) == S_IFREG) {
 730       JavaThread* thread = JavaThread::current();
 731       ResourceMark rm(thread);
 732       const char* canonical_path = get_canonical_path(path, thread);
 733       if (canonical_path != nullptr) {
 734         char* error_msg = nullptr;
 735         jzfile* zip = open_zip_file(canonical_path, &error_msg, thread);
 736         if (zip != nullptr && error_msg == nullptr) {
 737           // create using canonical path
 738           return new ClassPathZipEntry(zip, canonical_path);
 739         }
 740       }
 741     }
 742   }
 743   return nullptr;
 744 }
 745 
 746 // The boot append entries are added with a lock, and read lock free.
 747 void ClassLoader::add_to_boot_append_entries(ClassPathEntry *new_entry) {
 748   if (new_entry != nullptr) {
 749     MutexLocker ml(Bootclasspath_lock, Mutex::_no_safepoint_check_flag);
 750     if (_last_append_entry == nullptr) {
 751       _last_append_entry = new_entry;
 752       assert(first_append_entry() == nullptr, "boot loader's append class path entry list not empty");
 753       Atomic::release_store(&_first_append_entry_list, new_entry);
 754     } else {
 755       _last_append_entry->set_next(new_entry);
 756       _last_append_entry = new_entry;
 757     }
 758   }
 759 }
 760 
 761 // Returns true IFF the file/dir exists and the entry was successfully created.
 762 bool ClassLoader::update_class_path_entry_list(JavaThread* current, const char *path) {
 763   struct stat st;
 764   if (os::stat(path, &st) == 0) {
 765     // File or directory found
 766     ClassPathEntry* new_entry = nullptr;
 767     new_entry = create_class_path_entry(current, path, &st);
 768     if (new_entry == nullptr) {
 769       return false;
 770     }
 771 
 772     // Do not reorder the bootclasspath which would break get_system_package().
 773     // Add new entry to linked list
 774     add_to_boot_append_entries(new_entry);
 775     return true;
 776   } else {
 777     return false;
 778   }
 779 }
 780 
 781 static void print_module_entry_table(const GrowableArray<ModuleClassPathList*>* const module_list) {
 782   ResourceMark rm;
 783   int num_of_entries = module_list->length();
 784   for (int i = 0; i < num_of_entries; i++) {
 785     ClassPathEntry* e;
 786     ModuleClassPathList* mpl = module_list->at(i);
 787     tty->print("%s=", mpl->module_name()->as_C_string());
 788     e = mpl->module_first_entry();
 789     while (e != nullptr) {
 790       tty->print("%s", e->name());
 791       e = e->next();
 792       if (e != nullptr) {
 793         tty->print("%s", os::path_separator());
 794       }
 795     }
 796     tty->print(" ;");
 797   }
 798 }
 799 
 800 void ClassLoader::print_bootclasspath() {
 801   ClassPathEntry* e;
 802   tty->print("[bootclasspath= ");
 803 
 804   // Print --patch-module module/path specifications first
 805   if (_patch_mod_entries != nullptr) {
 806     print_module_entry_table(_patch_mod_entries);
 807   }
 808 
 809   // [jimage | exploded modules build]
 810   if (has_jrt_entry()) {
 811     // Print the location of the java runtime image
 812     tty->print("%s ;", _jrt_entry->name());
 813   } else {
 814     // Print exploded module build path specifications
 815     if (_exploded_entries != nullptr) {
 816       print_module_entry_table(_exploded_entries);
 817     }
 818   }
 819 
 820   // appended entries
 821   e = first_append_entry();
 822   while (e != nullptr) {
 823     tty->print("%s ;", e->name());
 824     e = e->next();
 825   }
 826   tty->print_cr("]");
 827 }
 828 
 829 void* ClassLoader::dll_lookup(void* lib, const char* name, const char* path) {
 830   void* func = os::dll_lookup(lib, name);
 831   if (func == nullptr) {
 832     char msg[256] = "";
 833     jio_snprintf(msg, sizeof(msg), "Could not resolve \"%s\"", name);
 834     vm_exit_during_initialization(msg, path);
 835   }
 836   return func;
 837 }
 838 
 839 void ClassLoader::load_java_library() {
 840   assert(CanonicalizeEntry == nullptr, "should not load java library twice");
 841   if (is_vm_statically_linked()) {
 842     CanonicalizeEntry = CAST_TO_FN_PTR(canonicalize_fn_t, os::lookup_function("JDK_Canonicalize"));
 843     assert(CanonicalizeEntry != nullptr, "could not lookup JDK_Canonicalize");
 844     return;
 845   }
 846 
 847   void *javalib_handle = os::native_java_library();
 848   if (javalib_handle == nullptr) {
 849     vm_exit_during_initialization("Unable to load java library", nullptr);
 850   }
 851 
 852   CanonicalizeEntry = CAST_TO_FN_PTR(canonicalize_fn_t, dll_lookup(javalib_handle, "JDK_Canonicalize", nullptr));
 853   assert(CanonicalizeEntry != nullptr, "could not lookup JDK_Canonicalize in java library");
 854 }
 855 
 856 void ClassLoader::load_jimage_library() {
 857   assert(JImageOpen == nullptr, "should not load jimage library twice");
 858 
 859   if (is_vm_statically_linked()) {
 860       JImageOpen = CAST_TO_FN_PTR(JImageOpen_t, os::lookup_function("JIMAGE_Open"));
 861       JImageClose = CAST_TO_FN_PTR(JImageClose_t, os::lookup_function("JIMAGE_Close"));
 862       JImageFindResource = CAST_TO_FN_PTR(JImageFindResource_t, os::lookup_function("JIMAGE_FindResource"));
 863       JImageGetResource = CAST_TO_FN_PTR(JImageGetResource_t, os::lookup_function("JIMAGE_GetResource"));
 864       assert(JImageOpen != nullptr && JImageClose != nullptr &&
 865             JImageFindResource != nullptr && JImageGetResource != nullptr,
 866             "could not lookup all jimage library functions");
 867       return;
 868     }
 869 
 870   char path[JVM_MAXPATHLEN];
 871   char ebuf[1024];
 872   void* handle = nullptr;
 873   if (os::dll_locate_lib(path, sizeof(path), Arguments::get_dll_dir(), "jimage")) {
 874     handle = os::dll_load(path, ebuf, sizeof ebuf);
 875   }
 876   if (handle == nullptr) {
 877     vm_exit_during_initialization("Unable to load jimage library", path);
 878   }
 879 
 880   JImageOpen = CAST_TO_FN_PTR(JImageOpen_t, dll_lookup(handle, "JIMAGE_Open", path));
 881   JImageClose = CAST_TO_FN_PTR(JImageClose_t, dll_lookup(handle, "JIMAGE_Close", path));
 882   JImageFindResource = CAST_TO_FN_PTR(JImageFindResource_t, dll_lookup(handle, "JIMAGE_FindResource", path));
 883   JImageGetResource = CAST_TO_FN_PTR(JImageGetResource_t, dll_lookup(handle, "JIMAGE_GetResource", path));
 884   assert(JImageOpen != nullptr && JImageClose != nullptr &&
 885         JImageFindResource != nullptr && JImageGetResource != nullptr,
 886         "could not lookup all jimage library functions in jimage library");
 887 }
 888 
 889 int ClassLoader::crc32(int crc, const char* buf, int len) {
 890   return ZipLibrary::crc32(crc, (const jbyte*)buf, len);
 891 }
 892 
 893 oop ClassLoader::get_system_package(const char* name, TRAPS) {
 894   // Look up the name in the boot loader's package entry table.
 895   if (name != nullptr) {
 896     TempNewSymbol package_sym = SymbolTable::new_symbol(name);
 897     // Look for the package entry in the boot loader's package entry table.
 898     PackageEntry* package =
 899       ClassLoaderData::the_null_class_loader_data()->packages()->lookup_only(package_sym);
 900 
 901     // Return null if package does not exist or if no classes in that package
 902     // have been loaded.
 903     if (package != nullptr && package->has_loaded_class()) {
 904       ModuleEntry* module = package->module();
 905       if (module->location() != nullptr) {
 906         ResourceMark rm(THREAD);
 907         Handle ml = java_lang_String::create_from_str(
 908           module->location()->as_C_string(), THREAD);
 909         return ml();
 910       }
 911       // Return entry on boot loader class path.
 912       Handle cph = java_lang_String::create_from_str(
 913         ClassLoader::classpath_entry(package->classpath_index())->name(), THREAD);
 914       return cph();
 915     }
 916   }
 917   return nullptr;
 918 }
 919 
 920 objArrayOop ClassLoader::get_system_packages(TRAPS) {
 921   ResourceMark rm(THREAD);
 922   // List of pointers to PackageEntrys that have loaded classes.
 923   PackageEntryTable* pe_table =
 924       ClassLoaderData::the_null_class_loader_data()->packages();
 925   GrowableArray<PackageEntry*>* loaded_class_pkgs = pe_table->get_system_packages();
 926 
 927   // Allocate objArray and fill with java.lang.String
 928   objArrayOop r = oopFactory::new_objArray(vmClasses::String_klass(),
 929                                            loaded_class_pkgs->length(), CHECK_NULL);
 930   objArrayHandle result(THREAD, r);
 931   for (int x = 0; x < loaded_class_pkgs->length(); x++) {
 932     PackageEntry* package_entry = loaded_class_pkgs->at(x);
 933     Handle str = java_lang_String::create_from_symbol(package_entry->name(), CHECK_NULL);
 934     result->obj_at_put(x, str());
 935   }
 936   return result();
 937 }
 938 
 939 // caller needs ResourceMark
 940 const char* ClassLoader::file_name_for_class_name(const char* class_name,
 941                                                   int class_name_len) {
 942   assert(class_name != nullptr, "invariant");
 943   assert((int)strlen(class_name) == class_name_len, "invariant");
 944 
 945   static const char class_suffix[] = ".class";
 946   size_t class_suffix_len = sizeof(class_suffix);
 947 
 948   char* const file_name = NEW_RESOURCE_ARRAY(char,
 949                                              class_name_len +
 950                                              class_suffix_len); // includes term null
 951 
 952   strncpy(file_name, class_name, class_name_len);
 953   strncpy(&file_name[class_name_len], class_suffix, class_suffix_len);
 954 
 955   return file_name;
 956 }
 957 
 958 static ClassPathEntry* find_first_module_cpe(ModuleEntry* mod_entry,
 959                                              const GrowableArray<ModuleClassPathList*>* const module_list) {
 960   int num_of_entries = module_list->length();
 961   const Symbol* class_module_name = mod_entry->name();
 962 
 963   // Loop through all the modules in either the patch-module or exploded entries looking for module
 964   for (int i = 0; i < num_of_entries; i++) {
 965     ModuleClassPathList* module_cpl = module_list->at(i);
 966     Symbol* module_cpl_name = module_cpl->module_name();
 967 
 968     if (module_cpl_name->fast_compare(class_module_name) == 0) {
 969       // Class' module has been located.
 970       return module_cpl->module_first_entry();
 971     }
 972   }
 973   return nullptr;
 974 }
 975 
 976 
 977 // Search the module list for the class file stream based on the file name and java package
 978 ClassFileStream* ClassLoader::search_module_entries(JavaThread* current,
 979                                                     const GrowableArray<ModuleClassPathList*>* const module_list,
 980                                                     PackageEntry* pkg_entry, // Java package entry derived from the class name
 981                                                     const char* const file_name) {
 982   ClassFileStream* stream = nullptr;
 983 
 984   // Find the defining module in the boot loader's module entry table
 985   ModuleEntry* mod_entry = (pkg_entry != nullptr) ? pkg_entry->module() : nullptr;
 986 
 987   // If the module system has not defined java.base yet, then
 988   // classes loaded are assumed to be defined to java.base.
 989   // When java.base is eventually defined by the module system,
 990   // all packages of classes that have been previously loaded
 991   // are verified in ModuleEntryTable::verify_javabase_packages().
 992   if (!Universe::is_module_initialized() &&
 993       !ModuleEntryTable::javabase_defined() &&
 994       mod_entry == nullptr) {
 995     mod_entry = ModuleEntryTable::javabase_moduleEntry();
 996   }
 997 
 998   // The module must be a named module
 999   ClassPathEntry* e = nullptr;
1000   if (mod_entry != nullptr && mod_entry->is_named()) {
1001     if (module_list == _exploded_entries) {
1002       // The exploded build entries can be added to at any time so a lock is
1003       // needed when searching them.
1004       assert(!ClassLoader::has_jrt_entry(), "Must be exploded build");
1005       MutexLocker ml(current, Module_lock);
1006       e = find_first_module_cpe(mod_entry, module_list);
1007     } else {
1008       e = find_first_module_cpe(mod_entry, module_list);
1009     }
1010   }
1011 
1012   // Try to load the class from the module's ClassPathEntry list.
1013   while (e != nullptr) {
1014     stream = e->open_stream(current, file_name);
1015     // No context.check is required since CDS is not supported
1016     // for an exploded modules build or if --patch-module is specified.
1017     if (nullptr != stream) {
1018       return stream;
1019     }
1020     e = e->next();
1021   }
1022   // If the module was located, break out even if the class was not
1023   // located successfully from that module's ClassPathEntry list.
1024   // There will not be another valid entry for that module.
1025   return nullptr;
1026 }
1027 
1028 // Called by the boot classloader to load classes
1029 InstanceKlass* ClassLoader::load_class(Symbol* name, PackageEntry* pkg_entry, bool search_append_only, TRAPS) {
1030   assert(name != nullptr, "invariant");
1031 
1032   ResourceMark rm(THREAD);
1033   HandleMark hm(THREAD);
1034 
1035   const char* const class_name = name->as_C_string();
1036 
1037   EventMarkClassLoading m("Loading class %s", class_name);
1038 
1039   const char* const file_name = file_name_for_class_name(class_name,
1040                                                          name->utf8_length());
1041   assert(file_name != nullptr, "invariant");
1042 
1043   // Lookup stream for parsing .class file
1044   ClassFileStream* stream = nullptr;
1045   s2 classpath_index = 0;
1046   ClassPathEntry* e = nullptr;
1047 
1048   // If search_append_only is true, boot loader visibility boundaries are
1049   // set to be _first_append_entry to the end. This includes:
1050   //   [-Xbootclasspath/a]; [jvmti appended entries]
1051   //
1052   // If search_append_only is false, boot loader visibility boundaries are
1053   // set to be the --patch-module entries plus the base piece. This includes:
1054   //   [--patch-module=<module>=<file>(<pathsep><file>)*]; [jimage | exploded module build]
1055   //
1056 
1057   // Load Attempt #1: --patch-module
1058   // Determine the class' defining module.  If it appears in the _patch_mod_entries,
1059   // attempt to load the class from those locations specific to the module.
1060   // Specifications to --patch-module can contain a partial number of classes
1061   // that are part of the overall module definition.  So if a particular class is not
1062   // found within its module specification, the search should continue to Load Attempt #2.
1063   // Note: The --patch-module entries are never searched if the boot loader's
1064   //       visibility boundary is limited to only searching the append entries.
1065   if (_patch_mod_entries != nullptr && !search_append_only) {
1066     assert(!CDSConfig::is_dumping_archive(), "CDS doesn't support --patch-module during dumping");
1067     stream = search_module_entries(THREAD, _patch_mod_entries, pkg_entry, file_name);
1068   }
1069 
1070   // Load Attempt #2: [jimage | exploded build]
1071   if (!search_append_only && (nullptr == stream)) {
1072     if (has_jrt_entry()) {
1073       e = _jrt_entry;
1074       stream = _jrt_entry->open_stream(THREAD, file_name);
1075     } else {
1076       // Exploded build - attempt to locate class in its defining module's location.
1077       assert(_exploded_entries != nullptr, "No exploded build entries present");
1078       assert(!CDSConfig::is_dumping_archive(), "CDS dumping doesn't support exploded build");
1079       stream = search_module_entries(THREAD, _exploded_entries, pkg_entry, file_name);
1080     }
1081   }
1082 
1083   // Load Attempt #3: [-Xbootclasspath/a]; [jvmti appended entries]
1084   if (search_append_only && (nullptr == stream)) {
1085     // For the boot loader append path search, the starting classpath_index
1086     // for the appended piece is always 1 to account for either the
1087     // _jrt_entry or the _exploded_entries.
1088     assert(classpath_index == 0, "The classpath_index has been incremented incorrectly");
1089     classpath_index = 1;
1090 
1091     e = first_append_entry();
1092     while (e != nullptr) {
1093       stream = e->open_stream(THREAD, file_name);
1094       if (nullptr != stream) {
1095         break;
1096       }
1097       e = e->next();
1098       ++classpath_index;
1099     }
1100   }
1101 
1102   if (nullptr == stream) {
1103     return nullptr;
1104   }
1105 
1106   ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data();
1107   Handle protection_domain;
1108   ClassLoadInfo cl_info(protection_domain);
1109 
1110   InstanceKlass* result = KlassFactory::create_from_stream(stream,
1111                                                            name,
1112                                                            loader_data,
1113                                                            cl_info,
1114                                                            CHECK_NULL);
1115   result->set_classpath_index(classpath_index);
1116   return result;
1117 }
1118 
1119 #if INCLUDE_CDS
1120 static const char* skip_uri_protocol(const char* source) {
1121   if (strncmp(source, "file:", 5) == 0) {
1122     // file: protocol path could start with file:/ or file:///
1123     // locate the char after all the forward slashes
1124     int offset = 5;
1125     while (*(source + offset) == '/') {
1126         offset++;
1127     }
1128     source += offset;
1129   // for non-windows platforms, move back one char as the path begins with a '/'
1130 #ifndef _WINDOWS
1131     source -= 1;
1132 #endif
1133   } else if (strncmp(source, "jrt:/", 5) == 0) {
1134     source += 5;
1135   }
1136   return source;
1137 }
1138 
1139 static char decode_percent_encoded(const char *str, size_t& index) {
1140   if (str[index] == '%'
1141       && isxdigit(str[index + 1])
1142       && isxdigit(str[index + 2])) {
1143     char hex[3];
1144     hex[0] = str[index + 1];
1145     hex[1] = str[index + 2];
1146     hex[2] = '\0';
1147     index += 2;
1148     return (char) strtol(hex, nullptr, 16);
1149   }
1150   return str[index];
1151 }
1152 
1153 char* ClassLoader::uri_to_path(const char* uri) {
1154   const size_t len = strlen(uri) + 1;
1155   char* path = NEW_RESOURCE_ARRAY(char, len);
1156 
1157   uri = skip_uri_protocol(uri);
1158 
1159   if (strncmp(uri, "//", 2) == 0) {
1160     // Skip the empty "authority" part
1161     uri += 2;
1162   }
1163 
1164 #ifdef _WINDOWS
1165   if (uri[0] == '/') {
1166     // Absolute path name on Windows does not begin with a slash
1167     uri += 1;
1168   }
1169 #endif
1170 
1171   size_t path_index = 0;
1172   for (size_t i = 0; i < strlen(uri); ++i) {
1173     char decoded = decode_percent_encoded(uri, i);
1174     path[path_index++] = decoded;
1175   }
1176   path[path_index] = '\0';
1177   return path;
1178 }
1179 
1180 // Record the shared classpath index and loader type for classes loaded
1181 // by the builtin loaders at dump time.
1182 void ClassLoader::record_result(JavaThread* current, InstanceKlass* ik,
1183                                 const ClassFileStream* stream, bool redefined) {
1184   assert(CDSConfig::is_dumping_archive(), "sanity");
1185   assert(stream != nullptr, "sanity");
1186 
1187   if (ik->is_hidden()) {
1188     record_hidden_class(ik);
1189     return;
1190   }
1191 
1192   oop loader = ik->class_loader();
1193   char* src = (char*)stream->source();
1194   if (src == nullptr) {
1195     if (loader == nullptr) {
1196       // JFR classes
1197       ik->set_shared_classpath_index(0);
1198     }
1199     return;
1200   }
1201 
1202   if (!SystemDictionaryShared::is_builtin_loader(ik->class_loader_data())) {
1203     // A class loaded by a user-defined classloader.
1204     assert(ik->shared_classpath_index() < 0, "not assigned yet");
1205     ik->set_shared_classpath_index(UNREGISTERED_INDEX);
1206     SystemDictionaryShared::set_shared_class_misc_info(ik, (ClassFileStream*)stream);
1207     return;
1208   }
1209 
1210   assert(has_jrt_entry(), "CDS dumping does not support exploded JDK build");
1211 
1212   ResourceMark rm(current);
1213   int classpath_index = -1;
1214   bool found_invalid = false;
1215 
1216   PackageEntry* pkg_entry = ik->package();
1217 
1218   if (!AOTClassLocationConfig::dumptime_is_ready()) {
1219     // The shared path table is set up after module system initialization.
1220     // The path table contains no entry before that. Any classes loaded prior
1221     // to the setup of the shared path table must be from the modules image.
1222     assert(stream->from_boot_loader_modules_image(), "stream must be loaded by boot loader from modules image");
1223     classpath_index = 0;
1224   } else {
1225     // Save the path from the file: protocol or the module name from the jrt: protocol
1226     // if no protocol prefix is found, path is the same as stream->source(). This path
1227     // must be valid since the class has been successfully parsed.
1228     const char* path = ClassLoader::uri_to_path(src);
1229     assert(path != nullptr, "sanity");
1230     AOTClassLocationConfig::dumptime_iterate([&] (AOTClassLocation* cl) {
1231       int i = cl->index();
1232       // for index 0 and the stream->source() is the modules image or has the jrt: protocol.
1233       // The class must be from the runtime modules image.
1234       if (cl->is_modules_image() && (stream->from_boot_loader_modules_image() || string_starts_with(src, "jrt:"))) {
1235         classpath_index = i;
1236       } else if (os::same_files(cl->path(), path)) {
1237         // If the path (from the class stream source) is the same as the shared
1238         // class or module path, then we have a match.
1239         // src may come from the App/Platform class loaders, which would canonicalize
1240         // the file name. We cannot use strcmp to check for equality against cs->path().
1241         // We must use os::same_files (which is faster than canonicalizing cs->path()).
1242 
1243         // null pkg_entry and pkg_entry in an unnamed module implies the class
1244         // is from the -cp or boot loader append path which consists of -Xbootclasspath/a
1245         // and jvmti appended entries.
1246         if ((pkg_entry == nullptr) || (pkg_entry->in_unnamed_module())) {
1247           // Ensure the index is within the -cp range before assigning
1248           // to the classpath_index.
1249           if (SystemDictionary::is_system_class_loader(loader) && cl->from_app_classpath()) {
1250             classpath_index = i;
1251           } else {
1252             if (cl->from_boot_classpath()) {
1253               if (loader != nullptr) {
1254                 // Probably loaded by jdk/internal/loader/ClassLoaders$BootClassLoader. Don't archive
1255                 // such classes.
1256                 found_invalid = true;
1257               } else {
1258                 classpath_index = i;
1259               }
1260             }
1261           }
1262         } else {
1263           // A class from a named module from the --module-path. Ensure the index is
1264           // within the --module-path range before assigning to the classpath_index.
1265           if ((pkg_entry != nullptr) && !(pkg_entry->in_unnamed_module()) && cl->from_module_path()) {
1266             classpath_index = i;
1267           }
1268         }
1269       }
1270       if (classpath_index >= 0 || found_invalid) {
1271         return false; // Break the AOTClassLocationConfig::dumptime_iterate() loop.
1272       } else {
1273         return true; // Keep iterating
1274       }
1275     });
1276   }
1277 
1278   if (found_invalid) {
1279     assert(classpath_index == -1, "sanity");
1280   }
1281 
1282   const char* const class_name = ik->name()->as_C_string();
1283   const char* const file_name = file_name_for_class_name(class_name,
1284                                                          ik->name()->utf8_length());
1285   assert(file_name != nullptr, "invariant");
1286   ClassLoaderExt::record_result_for_builtin_loader(checked_cast<s2>(classpath_index), ik, redefined);
1287 }
1288 
1289 void ClassLoader::record_hidden_class(InstanceKlass* ik) {
1290   assert(ik->is_hidden(), "must be");
1291 
1292   if (ik->defined_by_other_loaders()) {
1293     // We don't archive hidden classes for non-builtin loaders.
1294     return;
1295   }
1296 
1297   if (HeapShared::is_lambda_proxy_klass(ik)) {
1298     InstanceKlass* nest_host = ik->nest_host_not_null();
1299     ik->set_shared_classpath_index(nest_host->shared_classpath_index());
1300   } else if (HeapShared::is_lambda_form_klass(ik)) {
1301     ik->set_shared_classpath_index(0);
1302   } else {
1303     // Generated invoker classes.
1304     if (ik->defined_by_app_loader()) {
1305       ik->set_shared_classpath_index(AOTClassLocationConfig::dumptime()->app_cp_start_index());
1306     } else {
1307       ik->set_shared_classpath_index(0);
1308     }
1309   }
1310 }
1311 #endif // INCLUDE_CDS
1312 
1313 // Initialize the class loader's access to methods in libzip.  Parse and
1314 // process the boot classpath into a list ClassPathEntry objects.  Once
1315 // this list has been created, it must not change order (see class PackageInfo)
1316 // it can be appended to and is by jvmti.
1317 
1318 void ClassLoader::initialize(TRAPS) {
1319   if (UsePerfData) {
1320     // jvmstat performance counters
1321     NEWPERFTICKCOUNTER(_perf_accumulated_time, SUN_CLS, "time");
1322     NEWPERFTICKCOUNTER(_perf_class_init_time, SUN_CLS, "classInitTime");
1323     NEWPERFTICKCOUNTER(_perf_class_init_selftime, SUN_CLS, "classInitTime.self");
1324     NEWPERFTICKCOUNTER(_perf_class_verify_time, SUN_CLS, "classVerifyTime");
1325     NEWPERFTICKCOUNTER(_perf_class_verify_selftime, SUN_CLS, "classVerifyTime.self");
1326     NEWPERFTICKCOUNTER(_perf_class_link_time, SUN_CLS, "classLinkedTime");
1327     NEWPERFTICKCOUNTER(_perf_class_link_selftime, SUN_CLS, "classLinkedTime.self");
1328     NEWPERFEVENTCOUNTER(_perf_classes_inited, SUN_CLS, "initializedClasses");
1329     NEWPERFEVENTCOUNTER(_perf_classes_linked, SUN_CLS, "linkedClasses");
1330     NEWPERFEVENTCOUNTER(_perf_classes_verified, SUN_CLS, "verifiedClasses");
1331 
1332     NEWPERFTICKCOUNTER(_perf_shared_classload_time, SUN_CLS, "sharedClassLoadTime");
1333     NEWPERFTICKCOUNTER(_perf_sys_classload_time, SUN_CLS, "sysClassLoadTime");
1334     NEWPERFTICKCOUNTER(_perf_app_classload_time, SUN_CLS, "appClassLoadTime");
1335     NEWPERFTICKCOUNTER(_perf_app_classload_selftime, SUN_CLS, "appClassLoadTime.self");
1336     NEWPERFEVENTCOUNTER(_perf_app_classload_count, SUN_CLS, "appClassLoadCount");
1337     NEWPERFTICKCOUNTER(_perf_define_appclasses, SUN_CLS, "defineAppClasses");
1338     NEWPERFTICKCOUNTER(_perf_define_appclass_time, SUN_CLS, "defineAppClassTime");
1339     NEWPERFTICKCOUNTER(_perf_define_appclass_selftime, SUN_CLS, "defineAppClassTime.self");
1340     NEWPERFBYTECOUNTER(_perf_app_classfile_bytes_read, SUN_CLS, "appClassBytes");
1341     NEWPERFBYTECOUNTER(_perf_sys_classfile_bytes_read, SUN_CLS, "sysClassBytes");
1342     NEWPERFEVENTCOUNTER(_unsafe_defineClassCallCounter, SUN_CLS, "unsafeDefineClassCalls");
1343     NEWPERFTICKCOUNTER(_perf_secondary_hash_time, SUN_CLS, "secondarySuperHashTime");
1344 
1345     if (log_is_enabled(Info, perf, class, link)) {
1346       NEWPERFTICKCOUNTER(_perf_ik_link_methods_time, SUN_CLS, "linkMethodsTime");
1347       NEWPERFTICKCOUNTER(_perf_method_adapters_time, SUN_CLS, "makeAdaptersTime");
1348       NEWPERFEVENTCOUNTER(_perf_ik_link_methods_count, SUN_CLS, "linkMethodsCount");
1349       NEWPERFEVENTCOUNTER(_perf_method_adapters_count, SUN_CLS, "makeAdaptersCount");
1350 
1351       NEWPERFTICKCOUNTER(_perf_resolve_indy_time, SUN_CLS, "resolve_invokedynamic_time");
1352       NEWPERFTICKCOUNTER(_perf_resolve_invokehandle_time, SUN_CLS, "resolve_invokehandle_time");
1353       NEWPERFTICKCOUNTER(_perf_resolve_mh_time, SUN_CLS, "resolve_MethodHandle_time");
1354       NEWPERFTICKCOUNTER(_perf_resolve_mt_time, SUN_CLS, "resolve_MethodType_time");
1355 
1356       NEWPERFEVENTCOUNTER(_perf_resolve_indy_count, SUN_CLS, "resolve_invokedynamic_count");
1357       NEWPERFEVENTCOUNTER(_perf_resolve_invokehandle_count, SUN_CLS, "resolve_invokehandle_count");
1358       NEWPERFEVENTCOUNTER(_perf_resolve_mh_count, SUN_CLS, "resolve_MethodHandle_count");
1359       NEWPERFEVENTCOUNTER(_perf_resolve_mt_count, SUN_CLS, "resolve_MethodType_count");
1360     }
1361   }
1362 
1363   // lookup java library entry points
1364   load_java_library();
1365   // jimage library entry points are loaded below, in lookup_vm_options
1366   setup_bootstrap_search_path(THREAD);
1367 }
1368 
1369 static char* lookup_vm_resource(JImageFile *jimage, const char *jimage_version, const char *path) {
1370   jlong size;
1371   JImageLocationRef location = (*JImageFindResource)(jimage, "java.base", jimage_version, path, &size);
1372   if (location == 0)
1373     return nullptr;
1374   char *val = NEW_C_HEAP_ARRAY(char, size+1, mtClass);
1375   (*JImageGetResource)(jimage, location, val, size);
1376   val[size] = '\0';
1377   return val;
1378 }
1379 
1380 // Lookup VM options embedded in the modules jimage file
1381 char* ClassLoader::lookup_vm_options() {
1382   jint error;
1383   char modules_path[JVM_MAXPATHLEN];
1384   const char* fileSep = os::file_separator();
1385 
1386   // Initialize jimage library entry points
1387   load_jimage_library();
1388 
1389   jio_snprintf(modules_path, JVM_MAXPATHLEN, "%s%slib%smodules", Arguments::get_java_home(), fileSep, fileSep);
1390   JImage_file =(*JImageOpen)(modules_path, &error);
1391   if (JImage_file == nullptr) {
1392     return nullptr;
1393   }
1394 
1395   const char *jimage_version = get_jimage_version_string();
1396   char *options = lookup_vm_resource(JImage_file, jimage_version, "jdk/internal/vm/options");
1397   return options;
1398 }
1399 
1400 bool ClassLoader::is_module_observable(const char* module_name) {
1401   assert(JImageOpen != nullptr, "jimage library should have been opened");
1402   if (JImage_file == nullptr) {
1403     struct stat st;
1404     const char *path = get_exploded_module_path(module_name, true);
1405     bool res = os::stat(path, &st) == 0;
1406     FREE_C_HEAP_ARRAY(char, path);
1407     return res;
1408   }
1409   jlong size;
1410   const char *jimage_version = get_jimage_version_string();
1411   return (*JImageFindResource)(JImage_file, module_name, jimage_version, "module-info.class", &size) != 0;
1412 }
1413 
1414 jlong ClassLoader::classloader_time_ms() {
1415   return UsePerfData ?
1416     Management::ticks_to_ms(_perf_accumulated_time->get_value()) : -1;
1417 }
1418 
1419 jlong ClassLoader::class_init_count() {
1420   return UsePerfData ? _perf_classes_inited->get_value() : -1;
1421 }
1422 
1423 jlong ClassLoader::class_init_time_ms() {
1424   return UsePerfData ?
1425     Management::ticks_to_ms(_perf_class_init_time->get_value()) : -1;
1426 }
1427 
1428 jlong ClassLoader::class_verify_time_ms() {
1429   return UsePerfData ?
1430     Management::ticks_to_ms(_perf_class_verify_time->get_value()) : -1;
1431 }
1432 
1433 jlong ClassLoader::class_link_count() {
1434   return UsePerfData ? _perf_classes_linked->get_value() : -1;
1435 }
1436 
1437 jlong ClassLoader::class_link_time_ms() {
1438   return UsePerfData ?
1439     Management::ticks_to_ms(_perf_class_link_time->get_value()) : -1;
1440 }
1441 
1442 int ClassLoader::compute_Object_vtable() {
1443   // hardwired for JDK1.2 -- would need to duplicate class file parsing
1444   // code to determine actual value from file
1445   // Would be value '11' if finals were in vtable
1446   int JDK_1_2_Object_vtable_size = 5;
1447   return JDK_1_2_Object_vtable_size * vtableEntry::size();
1448 }
1449 
1450 
1451 void classLoader_init1() {
1452   EXCEPTION_MARK;
1453   ClassLoader::initialize(THREAD);
1454   if (HAS_PENDING_EXCEPTION) {
1455     vm_exit_during_initialization("ClassLoader::initialize() failed unexpectedly");
1456   }
1457 }
1458 
1459 // Complete the ClassPathEntry setup for the boot loader
1460 void ClassLoader::classLoader_init2(JavaThread* current) {
1461   // Setup the list of module/path pairs for --patch-module processing
1462   // This must be done after the SymbolTable is created in order
1463   // to use fast_compare on module names instead of a string compare.
1464   if (Arguments::get_patch_mod_prefix() != nullptr) {
1465     setup_patch_mod_entries();
1466   }
1467 
1468   // Create the ModuleEntry for java.base (must occur after setup_patch_mod_entries
1469   // to successfully determine if java.base has been patched)
1470   create_javabase();
1471 
1472   // Setup the initial java.base/path pair for the exploded build entries.
1473   // As more modules are defined during module system initialization, more
1474   // entries will be added to the exploded build array.
1475   if (!has_jrt_entry()) {
1476     assert(!CDSConfig::is_dumping_archive(), "not supported with exploded module builds");
1477     assert(!CDSConfig::is_using_archive(), "UsedSharedSpaces not supported with exploded module builds");
1478     // Set up the boot loader's _exploded_entries list.  Note that this gets
1479     // done before loading any classes, by the same thread that will
1480     // subsequently do the first class load. So, no lock is needed for this.
1481     assert(_exploded_entries == nullptr, "Should only get initialized once");
1482     _exploded_entries = new (mtModule)
1483       GrowableArray<ModuleClassPathList*>(EXPLODED_ENTRY_SIZE, mtModule);
1484     add_to_exploded_build_list(current, vmSymbols::java_base());
1485   }
1486 }
1487 
1488 char* ClassLoader::get_canonical_path(const char* orig, Thread* thread) {
1489   assert(orig != nullptr, "bad arguments");
1490   // caller needs to allocate ResourceMark for the following output buffer
1491   char* canonical_path = NEW_RESOURCE_ARRAY_IN_THREAD(thread, char, JVM_MAXPATHLEN);
1492   ResourceMark rm(thread);
1493   // os::native_path writes into orig_copy
1494   char* orig_copy = ResourceArea::strdup(thread, orig);
1495   if ((CanonicalizeEntry)(os::native_path(orig_copy), canonical_path, JVM_MAXPATHLEN) < 0) {
1496     return nullptr;
1497   }
1498   return canonical_path;
1499 }
1500 
1501 void ClassLoader::create_javabase() {
1502   JavaThread* current = JavaThread::current();
1503 
1504   // Create java.base's module entry for the boot
1505   // class loader prior to loading j.l.Object.
1506   ClassLoaderData* null_cld = ClassLoaderData::the_null_class_loader_data();
1507 
1508   // Get module entry table
1509   ModuleEntryTable* null_cld_modules = null_cld->modules();
1510   if (null_cld_modules == nullptr) {
1511     vm_exit_during_initialization("No ModuleEntryTable for the boot class loader");
1512   }
1513 
1514   {
1515     MutexLocker ml(current, Module_lock);
1516     if (ModuleEntryTable::javabase_moduleEntry() == nullptr) {  // may have been inited by CDS.
1517       ModuleEntry* jb_module = null_cld_modules->locked_create_entry(Handle(),
1518                                false, vmSymbols::java_base(), nullptr, nullptr, null_cld);
1519       if (jb_module == nullptr) {
1520         vm_exit_during_initialization("Unable to create ModuleEntry for " JAVA_BASE_NAME);
1521       }
1522       ModuleEntryTable::set_javabase_moduleEntry(jb_module);
1523     }
1524   }
1525 }
1526 
1527 // Please keep following two functions at end of this file. With them placed at top or in middle of the file,
1528 // they could get inlined by aggressive compiler, an unknown trick, see bug 6966589.
1529 void PerfClassTraceTime::initialize() {
1530   if (!UsePerfData) return;
1531 
1532   if (_eventp != nullptr) {
1533     // increment the event counter
1534     _eventp->inc();
1535   }
1536 
1537   // stop the current active thread-local timer to measure inclusive time
1538   _prev_active_event = -1;
1539   for (int i=0; i < EVENT_TYPE_COUNT; i++) {
1540      if (_timers[i].is_active()) {
1541        assert(_prev_active_event == -1, "should have only one active timer");
1542        _prev_active_event = i;
1543        _timers[i].stop();
1544      }
1545   }
1546 
1547   if (_recursion_counters == nullptr || (_recursion_counters[_event_type])++ == 0) {
1548     // start the inclusive timer if not recursively called
1549     _t.start();
1550   }
1551 
1552   // start thread-local timer of the given event type
1553    if (!_timers[_event_type].is_active()) {
1554     _timers[_event_type].start();
1555   }
1556 }
1557 
1558 PerfClassTraceTime::~PerfClassTraceTime() {
1559   if (!UsePerfData) return;
1560 
1561   // stop the thread-local timer as the event completes
1562   // and resume the thread-local timer of the event next on the stack
1563   _timers[_event_type].stop();
1564   jlong selftime = _timers[_event_type].ticks();
1565 
1566   if (_prev_active_event >= 0) {
1567     _timers[_prev_active_event].start();
1568   }
1569 
1570   if (_recursion_counters != nullptr && --(_recursion_counters[_event_type]) > 0) return;
1571 
1572   // increment the counters only on the leaf call
1573   _t.stop();
1574   _timep->inc(_t.ticks());
1575   if (_selftimep != nullptr) {
1576     _selftimep->inc(selftime);
1577   }
1578   // add all class loading related event selftime to the accumulated time counter
1579   ClassLoader::perf_accumulated_time()->inc(selftime);
1580 
1581   // reset the timer
1582   _timers[_event_type].reset();
1583 }