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