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