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 #ifndef SHARE_CLASSFILE_CLASSLOADER_HPP 26 #define SHARE_CLASSFILE_CLASSLOADER_HPP 27 28 #include "jimage.hpp" 29 #include "runtime/handles.hpp" 30 #include "runtime/perfDataTypes.hpp" 31 #include "utilities/exceptions.hpp" 32 #include "utilities/macros.hpp" 33 #include "utilities/ostream.hpp" 34 #include "utilities/zipLibrary.hpp" 35 36 // The VM class loader. 37 #include <sys/stat.h> 38 39 // Name of boot "modules" image 40 #define MODULES_IMAGE_NAME "modules" 41 42 // Class path entry (directory or zip file) 43 44 class JImageFile; 45 class ClassFileStream; 46 class PackageEntry; 47 template <typename T> class GrowableArray; 48 49 class ClassPathEntry : public CHeapObj<mtClass> { 50 private: 51 ClassPathEntry* volatile _next; 52 protected: 53 const char* copy_path(const char*path); 54 public: 55 ClassPathEntry* next() const; 56 virtual ~ClassPathEntry() {} 57 void set_next(ClassPathEntry* next); 58 59 virtual bool is_modules_image() const { return false; } 60 virtual bool is_jar_file() const { return false; } 61 virtual const char* name() const = 0; 62 virtual JImageFile* jimage() const { return nullptr; } 63 virtual void close_jimage() {} 64 // Constructor 65 ClassPathEntry() : _next(nullptr) {} 66 // Attempt to locate file_name through this class path entry. 67 // Returns a class file parsing stream if successful. 68 virtual ClassFileStream* open_stream(JavaThread* current, const char* name) = 0; 69 // Open the stream for a specific class loader 70 virtual ClassFileStream* open_stream_for_loader(JavaThread* current, const char* name, ClassLoaderData* loader_data) { 71 return open_stream(current, name); 72 } 73 }; 74 75 class ClassPathDirEntry: public ClassPathEntry { 76 private: 77 const char* _dir; // Name of directory 78 public: 79 const char* name() const { return _dir; } 80 ClassPathDirEntry(const char* dir) { 81 _dir = copy_path(dir); 82 } 83 virtual ~ClassPathDirEntry(); 84 ClassFileStream* open_stream(JavaThread* current, const char* name); 85 }; 86 87 class ClassPathZipEntry: public ClassPathEntry { 88 private: 89 jzfile* _zip; // The zip archive 90 const char* _zip_name; // Name of zip archive 91 public: 92 bool is_jar_file() const { return true; } 93 const char* name() const { return _zip_name; } 94 ClassPathZipEntry(jzfile* zip, const char* zip_name); 95 virtual ~ClassPathZipEntry(); 96 bool has_entry(JavaThread* current, const char* name); 97 u1* open_entry(JavaThread* current, const char* name, jint* filesize, bool nul_terminate); 98 ClassFileStream* open_stream(JavaThread* current, const char* name); 99 }; 100 101 102 // For java image files 103 class ClassPathImageEntry: public ClassPathEntry { 104 private: 105 const char* _name; 106 DEBUG_ONLY(static ClassPathImageEntry* _singleton;) 107 public: 108 bool is_modules_image() const; 109 const char* name() const { return _name == nullptr ? "" : _name; } 110 JImageFile* jimage() const; 111 JImageFile* jimage_non_null() const; 112 void close_jimage(); 113 ClassPathImageEntry(JImageFile* jimage, const char* name); 114 virtual ~ClassPathImageEntry() { ShouldNotReachHere(); } 115 ClassFileStream* open_stream(JavaThread* current, const char* name); 116 ClassFileStream* open_stream_for_loader(JavaThread* current, const char* name, ClassLoaderData* loader_data); 117 }; 118 119 // ModuleClassPathList contains a linked list of ClassPathEntry's 120 // that have been specified for a specific module. Currently, 121 // the only way to specify a module/path pair is via the --patch-module 122 // command line option. 123 class ModuleClassPathList : public CHeapObj<mtClass> { 124 private: 125 Symbol* _module_name; 126 // First and last entries of class path entries for a specific module 127 ClassPathEntry* _module_first_entry; 128 ClassPathEntry* _module_last_entry; 129 public: 130 Symbol* module_name() const { return _module_name; } 131 ClassPathEntry* module_first_entry() const { return _module_first_entry; } 132 ModuleClassPathList(Symbol* module_name); 133 ~ModuleClassPathList(); 134 void add_to_list(ClassPathEntry* new_entry); 135 }; 136 137 class ClassLoader: AllStatic { 138 public: 139 enum ClassLoaderType { 140 OTHER = 0, 141 BOOT_LOADER = 1, /* boot loader */ 142 PLATFORM_LOADER = 2, /* PlatformClassLoader */ 143 APP_LOADER = 3 /* AppClassLoader */ 144 }; 145 protected: 146 147 // Performance counters 148 static PerfCounter* _perf_accumulated_time; 149 static PerfCounter* _perf_classes_inited; 150 static PerfCounter* _perf_class_init_time; 151 static PerfCounter* _perf_class_init_selftime; 152 static PerfCounter* _perf_classes_verified; 153 static PerfCounter* _perf_class_verify_time; 154 static PerfCounter* _perf_class_verify_selftime; 155 static PerfCounter* _perf_classes_linked; 156 static PerfCounter* _perf_class_link_time; 157 static PerfCounter* _perf_class_link_selftime; 158 static PerfCounter* _perf_shared_classload_time; 159 static PerfCounter* _perf_sys_classload_time; 160 static PerfCounter* _perf_app_classload_time; 161 static PerfCounter* _perf_app_classload_selftime; 162 static PerfCounter* _perf_app_classload_count; 163 static PerfCounter* _perf_define_appclasses; 164 static PerfCounter* _perf_define_appclass_time; 165 static PerfCounter* _perf_define_appclass_selftime; 166 static PerfCounter* _perf_app_classfile_bytes_read; 167 static PerfCounter* _perf_sys_classfile_bytes_read; 168 static PerfCounter* _perf_ik_link_methods_time; 169 static PerfCounter* _perf_method_adapters_time; 170 static PerfCounter* _perf_ik_link_methods_count; 171 static PerfCounter* _perf_method_adapters_count; 172 173 static PerfCounter* _perf_resolve_indy_time; 174 static PerfCounter* _perf_resolve_invokehandle_time; 175 static PerfCounter* _perf_resolve_mh_time; 176 static PerfCounter* _perf_resolve_mt_time; 177 178 static PerfCounter* _perf_resolve_indy_count; 179 static PerfCounter* _perf_resolve_invokehandle_count; 180 static PerfCounter* _perf_resolve_mh_count; 181 static PerfCounter* _perf_resolve_mt_count; 182 183 static PerfCounter* _unsafe_defineClassCallCounter; 184 185 // Count the time taken to hash the scondary superclass arrays. 186 static PerfCounter* _perf_secondary_hash_time; 187 188 // The boot class path consists of 3 ordered pieces: 189 // 1. the module/path pairs specified to --patch-module 190 // --patch-module=<module>=<file>(<pathsep><file>)* 191 // 2. the base piece 192 // [jimage | build with exploded modules] 193 // 3. boot loader append path 194 // [-Xbootclasspath/a]; [jvmti appended entries] 195 // 196 // The boot loader must obey this order when attempting 197 // to load a class. 198 199 // 1. Contains the module/path pairs specified to --patch-module 200 static GrowableArray<ModuleClassPathList*>* _patch_mod_entries; 201 202 // 2. the base piece 203 // Contains the ClassPathEntry of the modular java runtime image. 204 // If no java runtime image is present, this indicates a 205 // build with exploded modules is being used instead. 206 static ClassPathEntry* _jrt_entry; 207 static GrowableArray<ModuleClassPathList*>* _exploded_entries; 208 enum { EXPLODED_ENTRY_SIZE = 80 }; // Initial number of exploded modules 209 210 // 3. the boot loader's append path 211 // [-Xbootclasspath/a]; [jvmti appended entries] 212 // Note: boot loader append path does not support named modules. 213 static ClassPathEntry* volatile _first_append_entry_list; 214 static ClassPathEntry* first_append_entry() { 215 return Atomic::load_acquire(&_first_append_entry_list); 216 } 217 218 // Last entry in linked list of appended ClassPathEntry instances 219 static ClassPathEntry* volatile _last_append_entry; 220 221 public: 222 223 static bool has_bootclasspath_append() { return first_append_entry() != nullptr; } 224 225 protected: 226 // Initialization: 227 // - setup the boot loader's system class path 228 // - setup the boot loader's patch mod entries, if present 229 // - create the ModuleEntry for java.base 230 static void setup_bootstrap_search_path(JavaThread* current); 231 static void setup_bootstrap_search_path_impl(JavaThread* current, const char *class_path); 232 static void setup_patch_mod_entries(); 233 static void create_javabase(); 234 235 static void* dll_lookup(void* lib, const char* name, const char* path); 236 static void load_java_library(); 237 static void load_jimage_library(); 238 239 public: 240 static void* zip_library_handle(); 241 static jzfile* open_zip_file(const char* canonical_path, char** error_msg, JavaThread* thread); 242 static ClassPathEntry* create_class_path_entry(JavaThread* current, 243 const char *path, const struct stat* st); 244 245 // Canonicalizes path names, so strcmp will work properly. This is mainly 246 // to avoid confusing the zip library 247 static char* get_canonical_path(const char* orig, Thread* thread); 248 static const char* file_name_for_class_name(const char* class_name, 249 int class_name_len); 250 static PackageEntry* get_package_entry(Symbol* pkg_name, ClassLoaderData* loader_data); 251 static int crc32(int crc, const char* buf, int len); 252 static bool update_class_path_entry_list(JavaThread* current, 253 const char *path); 254 static void print_bootclasspath(); 255 256 // Timing 257 static PerfCounter* perf_accumulated_time() { return _perf_accumulated_time; } 258 static PerfCounter* perf_classes_inited() { return _perf_classes_inited; } 259 static PerfCounter* perf_class_init_time() { return _perf_class_init_time; } 260 static PerfCounter* perf_class_init_selftime() { return _perf_class_init_selftime; } 261 static PerfCounter* perf_classes_verified() { return _perf_classes_verified; } 262 static PerfCounter* perf_class_verify_time() { return _perf_class_verify_time; } 263 static PerfCounter* perf_class_verify_selftime() { return _perf_class_verify_selftime; } 264 static PerfCounter* perf_classes_linked() { return _perf_classes_linked; } 265 static PerfCounter* perf_class_link_time() { return _perf_class_link_time; } 266 static PerfCounter* perf_class_link_selftime() { return _perf_class_link_selftime; } 267 static PerfCounter* perf_shared_classload_time() { return _perf_shared_classload_time; } 268 static PerfCounter* perf_secondary_hash_time() { 269 return _perf_secondary_hash_time; 270 } 271 static PerfCounter* perf_sys_classload_time() { return _perf_sys_classload_time; } 272 static PerfCounter* perf_app_classload_time() { return _perf_app_classload_time; } 273 static PerfCounter* perf_app_classload_selftime() { return _perf_app_classload_selftime; } 274 static PerfCounter* perf_app_classload_count() { return _perf_app_classload_count; } 275 static PerfCounter* perf_define_appclasses() { return _perf_define_appclasses; } 276 static PerfCounter* perf_define_appclass_time() { return _perf_define_appclass_time; } 277 static PerfCounter* perf_define_appclass_selftime() { return _perf_define_appclass_selftime; } 278 static PerfCounter* perf_app_classfile_bytes_read() { return _perf_app_classfile_bytes_read; } 279 static PerfCounter* perf_sys_classfile_bytes_read() { return _perf_sys_classfile_bytes_read; } 280 281 static PerfCounter* perf_ik_link_methods_time() { return _perf_ik_link_methods_time; } 282 static PerfCounter* perf_method_adapters_time() { return _perf_method_adapters_time; } 283 static PerfCounter* perf_ik_link_methods_count() { return _perf_ik_link_methods_count; } 284 static PerfCounter* perf_method_adapters_count() { return _perf_method_adapters_count; } 285 286 static PerfCounter* perf_resolve_invokedynamic_time() { return _perf_resolve_indy_time; } 287 static PerfCounter* perf_resolve_invokehandle_time() { return _perf_resolve_invokehandle_time; } 288 static PerfCounter* perf_resolve_method_handle_time() { return _perf_resolve_mh_time; } 289 static PerfCounter* perf_resolve_method_type_time() { return _perf_resolve_mt_time; } 290 291 static PerfCounter* perf_resolve_invokedynamic_count() { return _perf_resolve_indy_count; } 292 static PerfCounter* perf_resolve_invokehandle_count() { return _perf_resolve_invokehandle_count; } 293 static PerfCounter* perf_resolve_method_handle_count() { return _perf_resolve_mh_count; } 294 static PerfCounter* perf_resolve_method_type_count() { return _perf_resolve_mt_count; } 295 296 static void print_counters(outputStream *st); 297 298 // Record how many calls to Unsafe_DefineClass 299 static PerfCounter* unsafe_defineClassCallCounter() { 300 return _unsafe_defineClassCallCounter; 301 } 302 303 // Modular java runtime image is present vs. a build with exploded modules 304 static bool has_jrt_entry() { return (_jrt_entry != nullptr); } 305 static ClassPathEntry* get_jrt_entry() { return _jrt_entry; } 306 static void close_jrt_image(); 307 308 // Add a module's exploded directory to the boot loader's exploded module build list 309 static void add_to_exploded_build_list(JavaThread* current, Symbol* module_name); 310 311 // Search the module list for the class file stream based on the file name and java package 312 static ClassFileStream* search_module_entries(JavaThread* current, 313 const GrowableArray<ModuleClassPathList*>* const module_list, 314 PackageEntry* pkg_entry, // Java package entry derived from the class name 315 const char* const file_name); 316 317 // Load individual .class file 318 static InstanceKlass* load_class(Symbol* class_name, PackageEntry* pkg_entry, bool search_append_only, TRAPS); 319 320 // If the specified package has been loaded by the system, then returns 321 // the name of the directory or ZIP file that the package was loaded from. 322 // Returns null if the package was not loaded. 323 // Note: The specified name can either be the name of a class or package. 324 // If a package name is specified, then it must be "/"-separator and also 325 // end with a trailing "/". 326 static oop get_system_package(const char* name, TRAPS); 327 328 // Returns an array of Java strings representing all of the currently 329 // loaded system packages. 330 // Note: The package names returned are "/"-separated and end with a 331 // trailing "/". 332 static objArrayOop get_system_packages(TRAPS); 333 334 // Initialization 335 static void initialize(TRAPS); 336 static void classLoader_init2(JavaThread* current); 337 338 static int compute_Object_vtable(); 339 340 static ClassPathEntry* classpath_entry(int n); 341 342 static bool is_in_patch_mod_entries(Symbol* module_name); 343 344 #if INCLUDE_CDS 345 static char* uri_to_path(const char* uri); 346 static void record_result(JavaThread* current, InstanceKlass* ik, 347 const ClassFileStream* stream, bool redefined); 348 static void record_hidden_class(InstanceKlass* ik); 349 #endif 350 351 static char* lookup_vm_options(); 352 353 // Determines if the named module is present in the 354 // modules jimage file or in the exploded modules directory. 355 static bool is_module_observable(const char* module_name); 356 357 static JImageLocationRef jimage_find_resource(JImageFile* jf, const char* module_name, 358 const char* file_name, jlong &size); 359 360 static void trace_class_path(const char* msg, const char* name = nullptr); 361 362 // VM monitoring and management support 363 static jlong classloader_time_ms(); 364 static jlong class_method_total_size(); 365 static jlong class_init_count(); 366 static jlong class_init_time_ms(); 367 static jlong class_verify_time_ms(); 368 static jlong class_link_count(); 369 static jlong class_link_time_ms(); 370 371 // adds a class path to the boot append entries 372 static void add_to_boot_append_entries(ClassPathEntry* new_entry); 373 374 // creates a class path zip entry (returns null if JAR file cannot be opened) 375 static ClassPathZipEntry* create_class_path_zip_entry(const char *path); 376 377 static bool string_ends_with(const char* str, const char* str_to_find); 378 379 // Extract package name from a fully qualified class name 380 // *bad_class_name is set to true if there's a problem with parsing class_name, to 381 // distinguish from a class_name with no package name, as both cases have a null return value 382 static Symbol* package_from_class_name(const Symbol* class_name, bool* bad_class_name = nullptr); 383 384 // Debugging 385 static void verify() PRODUCT_RETURN; 386 }; 387 388 // PerfClassTraceTime is used to measure time for class loading related events. 389 // This class tracks cumulative time and exclusive time for specific event types. 390 // During the execution of one event, other event types (e.g. class loading and 391 // resolution) as well as recursive calls of the same event type could happen. 392 // Only one elapsed timer (cumulative) and one thread-local self timer (exclusive) 393 // (i.e. only one event type) are active at a time even multiple PerfClassTraceTime 394 // instances have been created as multiple events are happening. 395 class PerfClassTraceTime { 396 public: 397 enum { 398 CLASS_LOAD = 0, 399 CLASS_LINK = 1, 400 CLASS_VERIFY = 2, 401 CLASS_CLINIT = 3, 402 DEFINE_CLASS = 4, 403 EVENT_TYPE_COUNT = 5 404 }; 405 protected: 406 // _t tracks time from initialization to destruction of this timer instance 407 // including time for all other event types, and recursive calls of this type. 408 // When a timer is called recursively, the elapsedTimer _t would not be used. 409 elapsedTimer _t; 410 PerfLongCounter* _timep; 411 PerfLongCounter* _selftimep; 412 PerfLongCounter* _eventp; 413 // pointer to thread-local recursion counter and timer array 414 // The thread_local timers track cumulative time for specific event types 415 // exclusive of time for other event types, but including recursive calls 416 // of the same type. 417 int* _recursion_counters; 418 elapsedTimer* _timers; 419 int _event_type; 420 int _prev_active_event; 421 422 public: 423 424 inline PerfClassTraceTime(PerfLongCounter* timep, /* counter incremented with inclusive time */ 425 PerfLongCounter* selftimep, /* counter incremented with exclusive time */ 426 PerfLongCounter* eventp, /* event counter */ 427 int* recursion_counters, /* thread-local recursion counter array */ 428 elapsedTimer* timers, /* thread-local timer array */ 429 int type /* event type */ ) : 430 _timep(timep), _selftimep(selftimep), _eventp(eventp), _recursion_counters(recursion_counters), _timers(timers), _event_type(type) { 431 initialize(); 432 } 433 434 inline PerfClassTraceTime(PerfLongCounter* timep, /* counter incremented with inclusive time */ 435 elapsedTimer* timers, /* thread-local timer array */ 436 int type /* event type */ ) : 437 _timep(timep), _selftimep(nullptr), _eventp(nullptr), _recursion_counters(nullptr), _timers(timers), _event_type(type) { 438 initialize(); 439 } 440 441 ~PerfClassTraceTime(); 442 void initialize(); 443 }; 444 445 #endif // SHARE_CLASSFILE_CLASSLOADER_HPP