1 /*
2 * Copyright (c) 1997, 2024, 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 bool is_multi_release_jar() const { return false; }
62 virtual void set_multi_release_jar() {}
63 // Is this entry created from the "Class-path" attribute from a JAR Manifest?
64 virtual bool from_class_path_attr() const { return false; }
65 virtual const char* name() const = 0;
66 virtual JImageFile* jimage() const { return nullptr; }
67 virtual void close_jimage() {}
68 // Constructor
69 ClassPathEntry() : _next(nullptr) {}
70 // Attempt to locate file_name through this class path entry.
71 // Returns a class file parsing stream if successful.
72 virtual ClassFileStream* open_stream(JavaThread* current, const char* name) = 0;
73 // Open the stream for a specific class loader
74 virtual ClassFileStream* open_stream_for_loader(JavaThread* current, const char* name, ClassLoaderData* loader_data) {
75 return open_stream(current, name);
76 }
77 };
78
79 class ClassPathDirEntry: public ClassPathEntry {
80 private:
81 const char* _dir; // Name of directory
82 public:
83 const char* name() const { return _dir; }
84 ClassPathDirEntry(const char* dir) {
85 _dir = copy_path(dir);
86 }
87 virtual ~ClassPathDirEntry();
88 ClassFileStream* open_stream(JavaThread* current, const char* name);
89 };
90
91 class ClassPathZipEntry: public ClassPathEntry {
92 private:
93 jzfile* _zip; // The zip archive
94 const char* _zip_name; // Name of zip archive
95 bool _from_class_path_attr; // From the "Class-path" attribute of a jar file
96 bool _multi_release; // multi-release jar
97 public:
98 bool is_jar_file() const { return true; }
99 bool is_multi_release_jar() const { return _multi_release; }
100 void set_multi_release_jar() { _multi_release = true; }
101 bool from_class_path_attr() const { return _from_class_path_attr; }
102 const char* name() const { return _zip_name; }
103 ClassPathZipEntry(jzfile* zip, const char* zip_name, bool from_class_path_attr, bool multi_release);
104 virtual ~ClassPathZipEntry();
105 bool has_entry(JavaThread* current, const char* name);
106 u1* open_entry(JavaThread* current, const char* name, jint* filesize, bool nul_terminate);
107 ClassFileStream* open_stream(JavaThread* current, const char* name);
108 };
109
110
111 // For java image files
112 class ClassPathImageEntry: public ClassPathEntry {
113 private:
114 const char* _name;
115 DEBUG_ONLY(static ClassPathImageEntry* _singleton;)
116 public:
117 bool is_modules_image() const;
118 const char* name() const { return _name == nullptr ? "" : _name; }
119 JImageFile* jimage() const;
120 JImageFile* jimage_non_null() const;
121 void close_jimage();
122 ClassPathImageEntry(JImageFile* jimage, const char* name);
123 virtual ~ClassPathImageEntry() { ShouldNotReachHere(); }
124 ClassFileStream* open_stream(JavaThread* current, const char* name);
125 ClassFileStream* open_stream_for_loader(JavaThread* current, const char* name, ClassLoaderData* loader_data);
126 };
127
128 // ModuleClassPathList contains a linked list of ClassPathEntry's
129 // that have been specified for a specific module. Currently,
130 // the only way to specify a module/path pair is via the --patch-module
131 // command line option.
132 class ModuleClassPathList : public CHeapObj<mtClass> {
133 private:
134 Symbol* _module_name;
135 // First and last entries of class path entries for a specific module
136 ClassPathEntry* _module_first_entry;
137 ClassPathEntry* _module_last_entry;
138 public:
139 Symbol* module_name() const { return _module_name; }
140 ClassPathEntry* module_first_entry() const { return _module_first_entry; }
141 ModuleClassPathList(Symbol* module_name);
142 ~ModuleClassPathList();
143 void add_to_list(ClassPathEntry* new_entry);
144 };
145
146 class ClassLoader: AllStatic {
147 public:
148 enum ClassLoaderType {
149 OTHER = 0,
150 BOOT_LOADER = 1, /* boot loader */
151 PLATFORM_LOADER = 2, /* PlatformClassLoader */
152 APP_LOADER = 3 /* AppClassLoader */
153 };
154 protected:
155
156 // Performance counters
157 static PerfCounter* _perf_accumulated_time;
158 static PerfCounter* _perf_classes_inited;
159 static PerfCounter* _perf_class_init_time;
160 static PerfCounter* _perf_class_init_selftime;
161 static PerfCounter* _perf_class_init_bytecodes_count;
162 static PerfCounter* _perf_classes_verified;
163 static PerfCounter* _perf_class_verify_time;
164 static PerfCounter* _perf_class_verify_selftime;
165 static PerfCounter* _perf_classes_linked;
166 static PerfCounter* _perf_class_link_time;
167 static PerfCounter* _perf_class_link_selftime;
168 static PerfCounter* _perf_shared_classload_time;
169 static PerfCounter* _perf_sys_classload_time;
170 static PerfCounter* _perf_app_classload_time;
171 static PerfCounter* _perf_app_classload_selftime;
172 static PerfCounter* _perf_app_classload_count;
173 static PerfCounter* _perf_define_appclasses;
174 static PerfCounter* _perf_define_appclass_time;
175 static PerfCounter* _perf_define_appclass_selftime;
176 static PerfCounter* _perf_app_classfile_bytes_read;
177 static PerfCounter* _perf_sys_classfile_bytes_read;
178 static PerfCounter* _perf_preload_total_time;
179 static PerfCounter* _perf_preload_time;
180 static PerfCounter* _perf_prelink_time;
181 static PerfCounter* _perf_preinit_time;
182 static PerfCounter* _perf_preresolve_time;
183 static PerfCounter* _perf_ik_link_methods_time;
184 static PerfCounter* _perf_method_adapters_time;
185 static PerfCounter* _perf_ik_link_methods_count;
186 static PerfCounter* _perf_method_adapters_count;
187
188 static PerfTickCounters* _perf_resolve_indy_time;
189 static PerfTickCounters* _perf_resolve_invokehandle_time;
190 static PerfTickCounters* _perf_resolve_mh_time;
191 static PerfTickCounters* _perf_resolve_mt_time;
192
193 static PerfCounter* _perf_resolve_indy_count;
194 static PerfCounter* _perf_resolve_invokehandle_count;
195 static PerfCounter* _perf_resolve_mh_count;
196 static PerfCounter* _perf_resolve_mt_count;
197
198 static PerfCounter* _unsafe_defineClassCallCounter;
199
200 // Count the time taken to hash the scondary superclass arrays.
201 static PerfCounter* _perf_secondary_hash_time;
202
203 // The boot class path consists of 3 ordered pieces:
204 // 1. the module/path pairs specified to --patch-module
205 // --patch-module=<module>=<file>(<pathsep><file>)*
206 // 2. the base piece
207 // [jimage | build with exploded modules]
208 // 3. boot loader append path
209 // [-Xbootclasspath/a]; [jvmti appended entries]
210 //
211 // The boot loader must obey this order when attempting
212 // to load a class.
213
214 // 1. Contains the module/path pairs specified to --patch-module
215 static GrowableArray<ModuleClassPathList*>* _patch_mod_entries;
216
217 // 2. the base piece
218 // Contains the ClassPathEntry of the modular java runtime image.
219 // If no java runtime image is present, this indicates a
220 // build with exploded modules is being used instead.
221 static ClassPathEntry* _jrt_entry;
222 static GrowableArray<ModuleClassPathList*>* _exploded_entries;
223 enum { EXPLODED_ENTRY_SIZE = 80 }; // Initial number of exploded modules
224
225 // 3. the boot loader's append path
226 // [-Xbootclasspath/a]; [jvmti appended entries]
227 // Note: boot loader append path does not support named modules.
228 static ClassPathEntry* volatile _first_append_entry_list;
229 static ClassPathEntry* first_append_entry() {
230 return Atomic::load_acquire(&_first_append_entry_list);
231 }
232
233 // Last entry in linked list of appended ClassPathEntry instances
234 static ClassPathEntry* volatile _last_append_entry;
235
236 // Info used by CDS
237 CDS_ONLY(static ClassPathEntry* _app_classpath_entries;)
238 CDS_ONLY(static ClassPathEntry* _last_app_classpath_entry;)
239 CDS_ONLY(static ClassPathEntry* _module_path_entries;)
240 CDS_ONLY(static ClassPathEntry* _last_module_path_entry;)
241 CDS_ONLY(static void setup_app_search_path(JavaThread* current, const char* class_path);)
242 CDS_ONLY(static void setup_module_search_path(JavaThread* current, const char* path);)
243 static bool add_to_app_classpath_entries(JavaThread* current,
244 ClassPathEntry* entry,
245 bool check_for_duplicates);
246 CDS_ONLY(static void add_to_module_path_entries(const char* path,
247 ClassPathEntry* entry);)
248
249 public:
250 CDS_ONLY(static ClassPathEntry* app_classpath_entries() {return _app_classpath_entries;})
251 CDS_ONLY(static ClassPathEntry* module_path_entries() {return _module_path_entries;})
252
253 static bool has_bootclasspath_append() { return first_append_entry() != nullptr; }
254
255 protected:
256 // Initialization:
257 // - setup the boot loader's system class path
258 // - setup the boot loader's patch mod entries, if present
259 // - create the ModuleEntry for java.base
260 static void setup_bootstrap_search_path(JavaThread* current);
261 static void setup_bootstrap_search_path_impl(JavaThread* current, const char *class_path);
262 static void setup_patch_mod_entries();
263 static void create_javabase();
264
265 static void* dll_lookup(void* lib, const char* name, const char* path);
266 static void load_java_library();
267 static void load_jimage_library();
268
269 public:
270 static void* zip_library_handle();
271 static jzfile* open_zip_file(const char* canonical_path, char** error_msg, JavaThread* thread);
272 static ClassPathEntry* create_class_path_entry(JavaThread* current,
273 const char *path, const struct stat* st,
274 bool is_boot_append,
275 bool from_class_path_attr,
276 bool is_multi_release = false);
277
278 // Canonicalizes path names, so strcmp will work properly. This is mainly
279 // to avoid confusing the zip library
280 static char* get_canonical_path(const char* orig, Thread* thread);
281 static const char* file_name_for_class_name(const char* class_name,
282 int class_name_len);
283 static PackageEntry* get_package_entry(Symbol* pkg_name, ClassLoaderData* loader_data);
284 static int crc32(int crc, const char* buf, int len);
285 static bool update_class_path_entry_list(JavaThread* current,
286 const char *path,
287 bool check_for_duplicates,
288 bool is_boot_append,
289 bool from_class_path_attr);
290 static void print_bootclasspath();
291
292 // Timing
293 static PerfCounter* perf_accumulated_time() { return _perf_accumulated_time; }
294 static PerfCounter* perf_classes_inited() { return _perf_classes_inited; }
295 static PerfCounter* perf_class_init_time() { return _perf_class_init_time; }
296 static PerfCounter* perf_class_init_selftime() { return _perf_class_init_selftime; }
297 static PerfCounter* perf_classes_verified() { return _perf_classes_verified; }
298 static PerfCounter* perf_class_verify_time() { return _perf_class_verify_time; }
299 static PerfCounter* perf_class_verify_selftime() { return _perf_class_verify_selftime; }
300 static PerfCounter* perf_classes_linked() { return _perf_classes_linked; }
301 static PerfCounter* perf_class_link_time() { return _perf_class_link_time; }
302 static PerfCounter* perf_class_link_selftime() { return _perf_class_link_selftime; }
303 static PerfCounter* perf_shared_classload_time() { return _perf_shared_classload_time; }
304 static PerfCounter* perf_secondary_hash_time() {
305 return _perf_secondary_hash_time;
306 }
307 static PerfCounter* perf_sys_classload_time() { return _perf_sys_classload_time; }
308 static PerfCounter* perf_app_classload_time() { return _perf_app_classload_time; }
309 static PerfCounter* perf_app_classload_selftime() { return _perf_app_classload_selftime; }
310 static PerfCounter* perf_app_classload_count() { return _perf_app_classload_count; }
311 static PerfCounter* perf_define_appclasses() { return _perf_define_appclasses; }
312 static PerfCounter* perf_define_appclass_time() { return _perf_define_appclass_time; }
313 static PerfCounter* perf_define_appclass_selftime() { return _perf_define_appclass_selftime; }
314 static PerfCounter* perf_app_classfile_bytes_read() { return _perf_app_classfile_bytes_read; }
315 static PerfCounter* perf_sys_classfile_bytes_read() { return _perf_sys_classfile_bytes_read; }
316
317 static PerfCounter* perf_preload_total_time() { return _perf_preload_total_time; }
318 static PerfCounter* perf_preload_time() { return _perf_preload_time; }
319 static PerfCounter* perf_prelink_time() { return _perf_prelink_time; }
320 static PerfCounter* perf_preinit_time() { return _perf_preinit_time; }
321 static PerfCounter* perf_preresolve_time() { return _perf_preresolve_time; }
322 static PerfCounter* perf_ik_link_methods_time() { return _perf_ik_link_methods_time; }
323 static PerfCounter* perf_method_adapters_time() { return _perf_method_adapters_time; }
324 static PerfCounter* perf_ik_link_methods_count() { return _perf_ik_link_methods_count; }
325 static PerfCounter* perf_method_adapters_count() { return _perf_method_adapters_count; }
326
327 static PerfTickCounters* perf_resolve_invokedynamic_time() { return _perf_resolve_indy_time; }
328 static PerfTickCounters* perf_resolve_invokehandle_time() { return _perf_resolve_invokehandle_time; }
329 static PerfTickCounters* perf_resolve_method_handle_time() { return _perf_resolve_mh_time; }
330 static PerfTickCounters* perf_resolve_method_type_time() { return _perf_resolve_mt_time; }
331
332 static PerfCounter* perf_resolve_invokedynamic_count() { return _perf_resolve_indy_count; }
333 static PerfCounter* perf_resolve_invokehandle_count() { return _perf_resolve_invokehandle_count; }
334 static PerfCounter* perf_resolve_method_handle_count() { return _perf_resolve_mh_count; }
335 static PerfCounter* perf_resolve_method_type_count() { return _perf_resolve_mt_count; }
336
337 static PerfCounter* perf_class_init_bytecodes_count() { return _perf_class_init_bytecodes_count; }
338
339 static void print_counters(outputStream *st);
340
341 // Record how many calls to Unsafe_DefineClass
342 static PerfCounter* unsafe_defineClassCallCounter() {
343 return _unsafe_defineClassCallCounter;
344 }
345
346 // Modular java runtime image is present vs. a build with exploded modules
347 static bool has_jrt_entry() { return (_jrt_entry != nullptr); }
348 static ClassPathEntry* get_jrt_entry() { return _jrt_entry; }
349 static void close_jrt_image();
350
351 // Add a module's exploded directory to the boot loader's exploded module build list
352 static void add_to_exploded_build_list(JavaThread* current, Symbol* module_name);
353
354 // Search the module list for the class file stream based on the file name and java package
355 static ClassFileStream* search_module_entries(JavaThread* current,
356 const GrowableArray<ModuleClassPathList*>* const module_list,
357 PackageEntry* pkg_entry, // Java package entry derived from the class name
358 const char* const file_name);
359
360 // Load individual .class file
361 static InstanceKlass* load_class(Symbol* class_name, PackageEntry* pkg_entry, bool search_append_only, TRAPS);
362
363 // If the specified package has been loaded by the system, then returns
364 // the name of the directory or ZIP file that the package was loaded from.
365 // Returns null if the package was not loaded.
366 // Note: The specified name can either be the name of a class or package.
367 // If a package name is specified, then it must be "/"-separator and also
368 // end with a trailing "/".
369 static oop get_system_package(const char* name, TRAPS);
370
371 // Returns an array of Java strings representing all of the currently
372 // loaded system packages.
373 // Note: The package names returned are "/"-separated and end with a
374 // trailing "/".
375 static objArrayOop get_system_packages(TRAPS);
376
377 // Initialization
378 static void initialize(TRAPS);
379 static void classLoader_init2(JavaThread* current);
380 CDS_ONLY(static void initialize_shared_path(JavaThread* current);)
381 CDS_ONLY(static void initialize_module_path(TRAPS);)
382
383 static int compute_Object_vtable();
384
385 static ClassPathEntry* classpath_entry(int n);
386
387 static bool is_in_patch_mod_entries(Symbol* module_name);
388
389 #if INCLUDE_CDS
390 // Sharing dump and restore
391
392 // Helper function used by CDS code to get the number of boot classpath
393 // entries during shared classpath setup time.
394 static int num_boot_classpath_entries();
395
396 static ClassPathEntry* get_next_boot_classpath_entry(ClassPathEntry* e);
397
398 // Helper function used by CDS code to get the number of app classpath
399 // entries during shared classpath setup time.
400 static int num_app_classpath_entries();
401
402 // Helper function used by CDS code to get the number of module path
403 // entries during shared classpath setup time.
404 static int num_module_path_entries();
405 static void exit_with_path_failure(const char* error, const char* message);
406 static char* uri_to_path(const char* uri);
407 static void record_result(JavaThread* current, InstanceKlass* ik,
408 const ClassFileStream* stream, bool redefined);
409 static void record_hidden_class(InstanceKlass* ik);
410 #endif
411
412 static char* lookup_vm_options();
413
414 // Determines if the named module is present in the
415 // modules jimage file or in the exploded modules directory.
416 static bool is_module_observable(const char* module_name);
417
418 static JImageLocationRef jimage_find_resource(JImageFile* jf, const char* module_name,
419 const char* file_name, jlong &size);
420
421 static void trace_class_path(const char* msg, const char* name = nullptr);
422
423 // VM monitoring and management support
424 static jlong classloader_time_ms();
425 static jlong class_method_total_size();
426 static jlong class_init_count();
427 static jlong class_init_time_ms();
428 static jlong class_verify_time_ms();
429 static jlong class_link_count();
430 static jlong class_link_time_ms();
431 static jlong class_init_bytecodes_count();
432
433 // adds a class path to the boot append entries
434 static void add_to_boot_append_entries(ClassPathEntry* new_entry);
435
436 // creates a class path zip entry (returns null if JAR file cannot be opened)
437 static ClassPathZipEntry* create_class_path_zip_entry(const char *apath);
438
439 static bool string_ends_with(const char* str, const char* str_to_find);
440
441 // Extract package name from a fully qualified class name
442 // *bad_class_name is set to true if there's a problem with parsing class_name, to
443 // distinguish from a class_name with no package name, as both cases have a null return value
444 static Symbol* package_from_class_name(const Symbol* class_name, bool* bad_class_name = nullptr);
445
446 // Debugging
447 static void verify() PRODUCT_RETURN;
448 };
449
450 // PerfClassTraceTime is used to measure time for class loading related events.
451 // This class tracks cumulative time and exclusive time for specific event types.
452 // During the execution of one event, other event types (e.g. class loading and
453 // resolution) as well as recursive calls of the same event type could happen.
454 // Only one elapsed timer (cumulative) and one thread-local self timer (exclusive)
455 // (i.e. only one event type) are active at a time even multiple PerfClassTraceTime
456 // instances have been created as multiple events are happening.
457 class PerfClassTraceTime {
458 public:
459 enum {
460 CLASS_LOAD = 0,
461 CLASS_LINK = 1,
462 CLASS_VERIFY = 2,
463 CLASS_CLINIT = 3,
464 DEFINE_CLASS = 4,
465 EVENT_TYPE_COUNT = 5
466 };
467 protected:
468 // _t tracks time from initialization to destruction of this timer instance
469 // including time for all other event types, and recursive calls of this type.
470 // When a timer is called recursively, the elapsedTimer _t would not be used.
471 elapsedTimer _t;
472 PerfLongCounter* _timep;
473 PerfLongCounter* _selftimep;
474 PerfLongCounter* _eventp;
475 // pointer to thread-local recursion counter and timer array
476 // The thread_local timers track cumulative time for specific event types
477 // exclusive of time for other event types, but including recursive calls
478 // of the same type.
479 int* _recursion_counters;
480 elapsedTimer* _timers;
481 int _event_type;
482 int _prev_active_event;
483
484 public:
485
486 inline PerfClassTraceTime(PerfLongCounter* timep, /* counter incremented with inclusive time */
487 PerfLongCounter* selftimep, /* counter incremented with exclusive time */
488 PerfLongCounter* eventp, /* event counter */
489 int* recursion_counters, /* thread-local recursion counter array */
490 elapsedTimer* timers, /* thread-local timer array */
491 int type /* event type */ ) :
492 _timep(timep), _selftimep(selftimep), _eventp(eventp), _recursion_counters(recursion_counters), _timers(timers), _event_type(type) {
493 initialize();
494 }
495
496 inline PerfClassTraceTime(PerfLongCounter* timep, /* counter incremented with inclusive time */
497 elapsedTimer* timers, /* thread-local timer array */
498 int type /* event type */ ) :
499 _timep(timep), _selftimep(nullptr), _eventp(nullptr), _recursion_counters(nullptr), _timers(timers), _event_type(type) {
500 initialize();
501 }
502
503 ~PerfClassTraceTime();
504 void initialize();
505 };
506
507 #endif // SHARE_CLASSFILE_CLASSLOADER_HPP