1 /*
2 * Copyright (c) 1997, 2016, 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_VM_CLASSFILE_CLASSLOADER_HPP
26 #define SHARE_VM_CLASSFILE_CLASSLOADER_HPP
27
28 #include "runtime/orderAccess.hpp"
29 #include "runtime/perfData.hpp"
30 #include "utilities/exceptions.hpp"
31 #include "utilities/macros.hpp"
32
33 // The VM class loader.
34 #include <sys/stat.h>
35
36 // Name of boot "modules" image
37 #define MODULES_IMAGE_NAME "modules"
38
39 // Name of the resource containing mapping from module names to defining class loader type
40 #define MODULE_LOADER_MAP "jdk/internal/vm/cds/resources/ModuleLoaderMap.dat"
41
42 // Initial sizes of the following arrays are based on the generated ModuleLoaderMap.dat
43 #define INITIAL_BOOT_MODULES_ARRAY_SIZE 30
44 #define INITIAL_PLATFORM_MODULES_ARRAY_SIZE 15
45
46 // Class path entry (directory or zip file)
47
48 class JImageFile;
49 class ClassFileStream;
50
51 class ClassPathEntry : public CHeapObj<mtClass> {
52 private:
53 ClassPathEntry* volatile _next;
54 public:
55 // Next entry in class path
56 ClassPathEntry* next() const {
57 return (ClassPathEntry*) OrderAccess::load_ptr_acquire(&_next);
58 }
59 void set_next(ClassPathEntry* next) {
60 // may have unlocked readers, so ensure visibility.
61 OrderAccess::release_store_ptr(&_next, next);
62 }
63 virtual bool is_jrt() = 0;
64 virtual bool is_jar_file() const = 0;
65 virtual const char* name() const = 0;
66 virtual JImageFile* jimage() const = 0;
67 // Constructor
68 ClassPathEntry() : _next(NULL) {}
69 // Attempt to locate file_name through this class path entry.
70 // Returns a class file parsing stream if successfull.
71 virtual ClassFileStream* open_stream(const char* name, TRAPS) = 0;
72 virtual bool stream_exists(const char* name) = 0;
73 // Debugging
74 NOT_PRODUCT(virtual void compile_the_world(Handle loader, TRAPS) = 0;)
75 };
76
77 class ClassPathDirEntry: public ClassPathEntry {
78 private:
79 const char* _dir; // Name of directory
80 public:
81 bool is_jrt() { return false; }
82 bool is_jar_file() const { return false; }
83 const char* name() const { return _dir; }
84 JImageFile* jimage() const { return NULL; }
85 ClassPathDirEntry(const char* dir);
86 ClassFileStream* open_stream(const char* name, TRAPS);
87 bool stream_exists(const char* name) { return false; }
88 // Debugging
89 NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);)
90 };
91
92
93 // Type definitions for zip file and zip file entry
94 typedef void* jzfile;
95 typedef struct {
96 char *name; /* entry name */
97 jlong time; /* modification time */
98 jlong size; /* size of uncompressed data */
99 jlong csize; /* size of compressed data (zero if uncompressed) */
100 jint crc; /* crc of uncompressed data */
101 char *comment; /* optional zip file comment */
102 jbyte *extra; /* optional extra data */
103 jlong pos; /* position of LOC header (if negative) or data */
104 } jzentry;
105
106
107 class ClassPathZipEntry: public ClassPathEntry {
108 enum {
109 _unknown = 0,
110 _yes = 1,
111 _no = 2
112 };
113 private:
114 jzfile* _zip; // The zip archive
115 const char* _zip_name; // Name of zip archive
116 bool _is_boot_append; // entry coming from -Xbootclasspath/a
117 u1 _multi_versioned; // indicates if the jar file has multi-versioned entries.
118 // It can have value of "_unknown", "_yes", or "_no"
119 public:
120 bool is_jrt() { return false; }
121 bool is_jar_file() const { return true; }
122 const char* name() const { return _zip_name; }
123 JImageFile* jimage() const { return NULL; }
124 ClassPathZipEntry(jzfile* zip, const char* zip_name, bool is_boot_append);
125 ~ClassPathZipEntry();
126 u1* open_entry(const char* name, jint* filesize, bool nul_terminate, TRAPS);
127 u1* open_versioned_entry(const char* name, jint* filesize, TRAPS) NOT_CDS_RETURN_(NULL);
128 ClassFileStream* open_stream(const char* name, TRAPS);
129 void contents_do(void f(const char* name, void* context), void* context);
130 bool is_multiple_versioned(TRAPS) NOT_CDS_RETURN_(false);
131 bool stream_exists(const char* name);
132 // Debugging
133 NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);)
134 };
135
136
137 // For java image files
138 class ClassPathImageEntry: public ClassPathEntry {
139 private:
140 JImageFile* _jimage;
141 const char* _name;
142 public:
143 bool is_jrt();
144 bool is_jar_file() const { return false; }
145 bool is_open() const { return _jimage != NULL; }
146 const char* name() const { return _name == NULL ? "" : _name; }
147 JImageFile* jimage() const { return _jimage; }
148 ClassPathImageEntry(JImageFile* jimage, const char* name);
149 ~ClassPathImageEntry();
150 ClassFileStream* open_stream(const char* name, TRAPS);
151 bool stream_exists(const char* name) { return false; }
152
153 // Debugging
154 NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);)
155 };
156
157 // ModuleClassPathList contains a linked list of ClassPathEntry's
158 // that have been specified for a specific module. Currently,
159 // the only way to specify a module/path pair is via the --patch-module
160 // command line option.
161 class ModuleClassPathList : public CHeapObj<mtClass> {
162 private:
163 Symbol* _module_name;
164 // First and last entries of class path entries for a specific module
165 ClassPathEntry* _module_first_entry;
166 ClassPathEntry* _module_last_entry;
167 public:
168 Symbol* module_name() const { return _module_name; }
169 ClassPathEntry* module_first_entry() const { return _module_first_entry; }
170 ModuleClassPathList(Symbol* module_name);
171 ~ModuleClassPathList();
172 void add_to_list(ClassPathEntry* new_entry);
173 };
174
175 class SharedPathsMiscInfo;
176
177 class ClassLoader: AllStatic {
178 public:
179 enum ClassLoaderType {
180 BOOT_LOADER = 1, /* boot loader */
181 PLATFORM_LOADER = 2, /* PlatformClassLoader */
182 APP_LOADER = 3 /* AppClassLoader */
183 };
184 protected:
185
186 // Performance counters
187 static PerfCounter* _perf_accumulated_time;
188 static PerfCounter* _perf_classes_inited;
189 static PerfCounter* _perf_class_init_time;
190 static PerfCounter* _perf_class_init_selftime;
191 static PerfCounter* _perf_classes_verified;
192 static PerfCounter* _perf_class_verify_time;
193 static PerfCounter* _perf_class_verify_selftime;
194 static PerfCounter* _perf_classes_linked;
195 static PerfCounter* _perf_class_link_time;
196 static PerfCounter* _perf_class_link_selftime;
197 static PerfCounter* _perf_class_parse_time;
198 static PerfCounter* _perf_class_parse_selftime;
199 static PerfCounter* _perf_sys_class_lookup_time;
200 static PerfCounter* _perf_shared_classload_time;
201 static PerfCounter* _perf_sys_classload_time;
202 static PerfCounter* _perf_app_classload_time;
203 static PerfCounter* _perf_app_classload_selftime;
204 static PerfCounter* _perf_app_classload_count;
205 static PerfCounter* _perf_define_appclasses;
206 static PerfCounter* _perf_define_appclass_time;
207 static PerfCounter* _perf_define_appclass_selftime;
208 static PerfCounter* _perf_app_classfile_bytes_read;
209 static PerfCounter* _perf_sys_classfile_bytes_read;
210
211 static PerfCounter* _sync_systemLoaderLockContentionRate;
212 static PerfCounter* _sync_nonSystemLoaderLockContentionRate;
213 static PerfCounter* _sync_JVMFindLoadedClassLockFreeCounter;
214 static PerfCounter* _sync_JVMDefineClassLockFreeCounter;
215 static PerfCounter* _sync_JNIDefineClassLockFreeCounter;
216
217 static PerfCounter* _unsafe_defineClassCallCounter;
218 static PerfCounter* _isUnsyncloadClass;
219 static PerfCounter* _load_instance_class_failCounter;
220
221 // The boot class path consists of 3 ordered pieces:
222 // 1. the module/path pairs specified to --patch-module
223 // --patch-module=<module>=<file>(<pathsep><file>)*
224 // 2. the base piece
225 // [jimage | build with exploded modules]
226 // 3. boot loader append path
227 // [-Xbootclasspath/a]; [jvmti appended entries]
228 //
229 // The boot loader must obey this order when attempting
230 // to load a class.
231
232 // 1. Contains the module/path pairs specified to --patch-module
233 static GrowableArray<ModuleClassPathList*>* _patch_mod_entries;
234
235 // 2. the base piece
236 // Contains the ClassPathEntry of the modular java runtime image.
237 // If no java runtime image is present, this indicates a
238 // build with exploded modules is being used instead.
239 static ClassPathEntry* _jrt_entry;
240 static GrowableArray<ModuleClassPathList*>* _exploded_entries;
241 enum { EXPLODED_ENTRY_SIZE = 80 }; // Initial number of exploded modules
242
243 // 3. the boot loader's append path
244 // [-Xbootclasspath/a]; [jvmti appended entries]
245 // Note: boot loader append path does not support named modules.
246 static ClassPathEntry* _first_append_entry;
247 // Last entry in linked list of appended ClassPathEntry instances
248 static ClassPathEntry* _last_append_entry;
249
250 // Note: _num_entries includes the java runtime image and all
251 // the entries on the _first_append_entry linked list.
252 static int _num_entries;
253
254 // Array of module names associated with the boot class loader
255 CDS_ONLY(static GrowableArray<char*>* _boot_modules_array;)
256
257 // Array of module names associated with the platform class loader
258 CDS_ONLY(static GrowableArray<char*>* _platform_modules_array;)
259
260 // Info used by CDS
261 CDS_ONLY(static SharedPathsMiscInfo * _shared_paths_misc_info;)
262 CDS_ONLY(static int _num_patch_mod_prefixes;)
263
264 // Initialization:
265 // - setup the boot loader's system class path
266 // - setup the boot loader's patch mod entries, if present
267 // - create the ModuleEntry for java.base
268 static void setup_bootstrap_search_path();
269 static void setup_search_path(const char *class_path, bool setting_bootstrap);
270 static void setup_patch_mod_entries();
271 static void create_javabase();
272
273 static void load_zip_library();
274 static void load_jimage_library();
275 static ClassPathEntry* create_class_path_entry(const char *path, const struct stat* st,
276 bool throw_exception,
277 bool is_boot_append, TRAPS);
278
279 public:
280
281 // If the package for the fully qualified class name is in the boot
282 // loader's package entry table then add_package() sets the classpath_index
283 // field so that get_system_package() will know to return a non-null value
284 // for the package's location. And, so that the package will be added to
285 // the list of packages returned by get_system_packages().
286 // For packages whose classes are loaded from the boot loader class path, the
287 // classpath_index indicates which entry on the boot loader class path.
288 static bool add_package(const char *fullq_class_name, s2 classpath_index, TRAPS);
289
290 // Canonicalizes path names, so strcmp will work properly. This is mainly
291 // to avoid confusing the zip library
292 static bool get_canonical_path(const char* orig, char* out, int len);
293 static const char* file_name_for_class_name(const char* class_name,
294 int class_name_len);
295
296 public:
297 static jboolean decompress(void *in, u8 inSize, void *out, u8 outSize, char **pmsg);
298 static int crc32(int crc, const char* buf, int len);
299 static bool update_class_path_entry_list(const char *path,
300 bool check_for_duplicates,
301 bool is_boot_append,
302 bool throw_exception=true);
303 static void print_bootclasspath();
304
305 // Timing
306 static PerfCounter* perf_accumulated_time() { return _perf_accumulated_time; }
307 static PerfCounter* perf_classes_inited() { return _perf_classes_inited; }
308 static PerfCounter* perf_class_init_time() { return _perf_class_init_time; }
309 static PerfCounter* perf_class_init_selftime() { return _perf_class_init_selftime; }
310 static PerfCounter* perf_classes_verified() { return _perf_classes_verified; }
311 static PerfCounter* perf_class_verify_time() { return _perf_class_verify_time; }
312 static PerfCounter* perf_class_verify_selftime() { return _perf_class_verify_selftime; }
313 static PerfCounter* perf_classes_linked() { return _perf_classes_linked; }
314 static PerfCounter* perf_class_link_time() { return _perf_class_link_time; }
315 static PerfCounter* perf_class_link_selftime() { return _perf_class_link_selftime; }
316 static PerfCounter* perf_class_parse_time() { return _perf_class_parse_time; }
317 static PerfCounter* perf_class_parse_selftime() { return _perf_class_parse_selftime; }
318 static PerfCounter* perf_sys_class_lookup_time() { return _perf_sys_class_lookup_time; }
319 static PerfCounter* perf_shared_classload_time() { return _perf_shared_classload_time; }
320 static PerfCounter* perf_sys_classload_time() { return _perf_sys_classload_time; }
321 static PerfCounter* perf_app_classload_time() { return _perf_app_classload_time; }
322 static PerfCounter* perf_app_classload_selftime() { return _perf_app_classload_selftime; }
323 static PerfCounter* perf_app_classload_count() { return _perf_app_classload_count; }
324 static PerfCounter* perf_define_appclasses() { return _perf_define_appclasses; }
325 static PerfCounter* perf_define_appclass_time() { return _perf_define_appclass_time; }
326 static PerfCounter* perf_define_appclass_selftime() { return _perf_define_appclass_selftime; }
327 static PerfCounter* perf_app_classfile_bytes_read() { return _perf_app_classfile_bytes_read; }
328 static PerfCounter* perf_sys_classfile_bytes_read() { return _perf_sys_classfile_bytes_read; }
329
330 // Record how often system loader lock object is contended
331 static PerfCounter* sync_systemLoaderLockContentionRate() {
332 return _sync_systemLoaderLockContentionRate;
333 }
334
335 // Record how often non system loader lock object is contended
336 static PerfCounter* sync_nonSystemLoaderLockContentionRate() {
337 return _sync_nonSystemLoaderLockContentionRate;
338 }
339
340 // Record how many calls to JVM_FindLoadedClass w/o holding a lock
341 static PerfCounter* sync_JVMFindLoadedClassLockFreeCounter() {
342 return _sync_JVMFindLoadedClassLockFreeCounter;
343 }
344
345 // Record how many calls to JVM_DefineClass w/o holding a lock
346 static PerfCounter* sync_JVMDefineClassLockFreeCounter() {
347 return _sync_JVMDefineClassLockFreeCounter;
348 }
349
350 // Record how many calls to jni_DefineClass w/o holding a lock
351 static PerfCounter* sync_JNIDefineClassLockFreeCounter() {
352 return _sync_JNIDefineClassLockFreeCounter;
353 }
354
355 // Record how many calls to Unsafe_DefineClass
356 static PerfCounter* unsafe_defineClassCallCounter() {
357 return _unsafe_defineClassCallCounter;
358 }
359
360 // Record how many times SystemDictionary::load_instance_class call
361 // fails with linkageError when Unsyncloadclass flag is set.
362 static PerfCounter* load_instance_class_failCounter() {
363 return _load_instance_class_failCounter;
364 }
365
366 // Modular java runtime image is present vs. a build with exploded modules
367 static bool has_jrt_entry() { return (_jrt_entry != NULL); }
368 static ClassPathEntry* get_jrt_entry() { return _jrt_entry; }
369
370 // Add a module's exploded directory to the boot loader's exploded module build list
371 static void add_to_exploded_build_list(Symbol* module_name, TRAPS);
372
373 // Attempt load of individual class from either the patched or exploded modules build lists
374 static ClassFileStream* search_module_entries(const GrowableArray<ModuleClassPathList*>* const module_list,
375 const char* const class_name,
376 const char* const file_name, TRAPS);
377
378 // Load individual .class file
379 static instanceKlassHandle load_class(Symbol* class_name, bool search_append_only, TRAPS);
380
381 // If the specified package has been loaded by the system, then returns
382 // the name of the directory or ZIP file that the package was loaded from.
383 // Returns null if the package was not loaded.
384 // Note: The specified name can either be the name of a class or package.
385 // If a package name is specified, then it must be "/"-separator and also
386 // end with a trailing "/".
387 static oop get_system_package(const char* name, TRAPS);
388
389 // Returns an array of Java strings representing all of the currently
390 // loaded system packages.
391 // Note: The package names returned are "/"-separated and end with a
392 // trailing "/".
393 static objArrayOop get_system_packages(TRAPS);
394
395 // Initialization
396 static void initialize();
397 static void classLoader_init2(TRAPS);
398 CDS_ONLY(static void initialize_shared_path();)
399
400 static int compute_Object_vtable();
401
402 static ClassPathEntry* classpath_entry(int n) {
403 if (n == 0) {
404 assert(has_jrt_entry(), "No class path entry at 0 for exploded module builds");
405 return ClassLoader::_jrt_entry;
406 } else {
407 // The java runtime image is always the first entry
408 // in the FileMapInfo::_classpath_entry_table. Even though
409 // the _jrt_entry is not included in the _first_append_entry
410 // linked list, it must be accounted for when comparing the
411 // class path vs. the shared archive class path.
412 ClassPathEntry* e = ClassLoader::_first_append_entry;
413 while (--n >= 1) {
414 assert(e != NULL, "Not that many classpath entries.");
415 e = e->next();
416 }
417 return e;
418 }
419 }
420
421 #if INCLUDE_CDS
422 // Sharing dump and restore
423
424 static void check_shared_classpath(const char *path);
425 static void finalize_shared_paths_misc_info();
426 static int get_shared_paths_misc_info_size();
427 static void* get_shared_paths_misc_info();
428 static bool check_shared_paths_misc_info(void* info, int size);
429 static void exit_with_path_failure(const char* error, const char* message);
430
431 static s2 module_to_classloader(const char* module_name);
432 static void initialize_module_loader_map(JImageFile* jimage);
433 static s2 classloader_type(Symbol* class_name, ClassPathEntry* e,
434 int classpath_index, TRAPS);
435 static bool is_in_patch_module(const char* const file_name);
436 static void setup_patch_mod_path(); // Only when -Xshare:dump
437 static int num_patch_mod_prefixes() { return _num_patch_mod_prefixes; }
438 #endif
439
440 static void trace_class_path(const char* msg, const char* name = NULL);
441
442 // VM monitoring and management support
443 static jlong classloader_time_ms();
444 static jlong class_method_total_size();
445 static jlong class_init_count();
446 static jlong class_init_time_ms();
447 static jlong class_verify_time_ms();
448 static jlong class_link_count();
449 static jlong class_link_time_ms();
450
451 static void set_first_append_entry(ClassPathEntry* entry);
452
453 // indicates if class path already contains a entry (exact match by name)
454 static bool contains_entry(ClassPathEntry* entry);
455
456 // adds a class path list
457 static void add_to_list(ClassPathEntry* new_entry);
458
459 // creates a class path zip entry (returns NULL if JAR file cannot be opened)
460 static ClassPathZipEntry* create_class_path_zip_entry(const char *apath, bool is_boot_append);
461
462 // add a path to class path list
463 static void add_to_list(const char* apath);
464
465 static bool string_ends_with(const char* str, const char* str_to_find);
466
467 // obtain package name from a fully qualified class name
468 // *bad_class_name is set to true if there's a problem with parsing class_name, to
469 // distinguish from a class_name with no package name, as both cases have a NULL return value
470 static const char* package_from_name(const char* const class_name, bool* bad_class_name = NULL);
471
472 static bool is_jrt(const char* name) { return string_ends_with(name, MODULES_IMAGE_NAME); }
473
474 // Debugging
475 static void verify() PRODUCT_RETURN;
476
477 // Force compilation of all methods in all classes in bootstrap class path (stress test)
478 #ifndef PRODUCT
479 protected:
480 static int _compile_the_world_class_counter;
481 static int _compile_the_world_method_counter;
482 public:
483 static void compile_the_world();
484 static void compile_the_world_in(char* name, Handle loader, TRAPS);
485 static int compile_the_world_counter() { return _compile_the_world_class_counter; }
486 #endif //PRODUCT
487 };
488
489 // PerfClassTraceTime is used to measure time for class loading related events.
490 // This class tracks cumulative time and exclusive time for specific event types.
491 // During the execution of one event, other event types (e.g. class loading and
492 // resolution) as well as recursive calls of the same event type could happen.
493 // Only one elapsed timer (cumulative) and one thread-local self timer (exclusive)
494 // (i.e. only one event type) are active at a time even multiple PerfClassTraceTime
495 // instances have been created as multiple events are happening.
496 class PerfClassTraceTime {
497 public:
498 enum {
499 CLASS_LOAD = 0,
500 PARSE_CLASS = 1,
501 CLASS_LINK = 2,
502 CLASS_VERIFY = 3,
503 CLASS_CLINIT = 4,
504 DEFINE_CLASS = 5,
505 EVENT_TYPE_COUNT = 6
506 };
507 protected:
508 // _t tracks time from initialization to destruction of this timer instance
509 // including time for all other event types, and recursive calls of this type.
510 // When a timer is called recursively, the elapsedTimer _t would not be used.
511 elapsedTimer _t;
512 PerfLongCounter* _timep;
513 PerfLongCounter* _selftimep;
514 PerfLongCounter* _eventp;
515 // pointer to thread-local recursion counter and timer array
516 // The thread_local timers track cumulative time for specific event types
517 // exclusive of time for other event types, but including recursive calls
518 // of the same type.
519 int* _recursion_counters;
520 elapsedTimer* _timers;
521 int _event_type;
522 int _prev_active_event;
523
524 public:
525
526 inline PerfClassTraceTime(PerfLongCounter* timep, /* counter incremented with inclusive time */
527 PerfLongCounter* selftimep, /* counter incremented with exclusive time */
528 PerfLongCounter* eventp, /* event counter */
529 int* recursion_counters, /* thread-local recursion counter array */
530 elapsedTimer* timers, /* thread-local timer array */
531 int type /* event type */ ) :
532 _timep(timep), _selftimep(selftimep), _eventp(eventp), _recursion_counters(recursion_counters), _timers(timers), _event_type(type) {
533 initialize();
534 }
535
536 inline PerfClassTraceTime(PerfLongCounter* timep, /* counter incremented with inclusive time */
537 elapsedTimer* timers, /* thread-local timer array */
538 int type /* event type */ ) :
539 _timep(timep), _selftimep(NULL), _eventp(NULL), _recursion_counters(NULL), _timers(timers), _event_type(type) {
540 initialize();
541 }
542
543 inline void suspend() { _t.stop(); _timers[_event_type].stop(); }
544 inline void resume() { _t.start(); _timers[_event_type].start(); }
545
546 ~PerfClassTraceTime();
547 void initialize();
548 };
549
550 #endif // SHARE_VM_CLASSFILE_CLASSLOADER_HPP