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