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