1 /*
2 * Copyright (c) 1997, 2017, 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 "classfile/jimage.hpp"
29 #include "runtime/orderAccess.hpp"
30 #include "runtime/perfData.hpp"
31 #include "utilities/exceptions.hpp"
32 #include "utilities/macros.hpp"
33
34 // The VM class loader.
35 #include <sys/stat.h>
36
37 // Name of boot "modules" image
38 #define MODULES_IMAGE_NAME "modules"
39
40 // Class path entry (directory or zip file)
41
42 class JImageFile;
43 class ClassFileStream;
44 class PackageEntry;
45
46 class ClassPathEntry : public CHeapObj<mtClass> {
47 private:
48 ClassPathEntry* volatile _next;
49 public:
50 // Next entry in class path
51 ClassPathEntry* next() const {
52 return (ClassPathEntry*) OrderAccess::load_ptr_acquire(&_next);
53 }
54 virtual ~ClassPathEntry() {}
55 void set_next(ClassPathEntry* next) {
56 // may have unlocked readers, so ensure visibility.
57 OrderAccess::release_store_ptr(&_next, next);
58 }
59 virtual bool is_jrt() = 0;
60 virtual bool is_jar_file() const = 0;
61 virtual const char* name() const = 0;
62 virtual JImageFile* jimage() const = 0;
63 // Constructor
64 ClassPathEntry() : _next(NULL) {}
65 // Attempt to locate file_name through this class path entry.
66 // Returns a class file parsing stream if successfull.
67 virtual ClassFileStream* open_stream(const char* name, TRAPS) = 0;
68 // Debugging
69 NOT_PRODUCT(virtual void compile_the_world(Handle loader, TRAPS) = 0;)
70 };
71
72 class ClassPathDirEntry: public ClassPathEntry {
73 private:
74 const char* _dir; // Name of directory
75 public:
76 bool is_jrt() { return false; }
77 bool is_jar_file() const { return false; }
78 const char* name() const { return _dir; }
79 JImageFile* jimage() const { return NULL; }
80 ClassPathDirEntry(const char* dir);
81 virtual ~ClassPathDirEntry() {}
82 ClassFileStream* open_stream(const char* name, TRAPS);
83 // Debugging
84 NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);)
85 };
86
87
88 // Type definitions for zip file and zip file entry
89 typedef void* jzfile;
90 typedef struct {
91 char *name; /* entry name */
92 jlong time; /* modification time */
93 jlong size; /* size of uncompressed data */
94 jlong csize; /* size of compressed data (zero if uncompressed) */
95 jint crc; /* crc of uncompressed data */
96 char *comment; /* optional zip file comment */
97 jbyte *extra; /* optional extra data */
98 jlong pos; /* position of LOC header (if negative) or data */
99 } jzentry;
100
101 class ClassPathZipEntry: public ClassPathEntry {
102 enum {
103 _unknown = 0,
104 _yes = 1,
105 _no = 2
106 };
107 private:
108 jzfile* _zip; // The zip archive
109 const char* _zip_name; // Name of zip archive
110 bool _is_boot_append; // entry coming from -Xbootclasspath/a
111 u1 _multi_versioned; // indicates if the jar file has multi-versioned entries.
112 // It can have value of "_unknown", "_yes", or "_no"
113 public:
114 bool is_jrt() { return false; }
115 bool is_jar_file() const { return true; }
116 const char* name() const { return _zip_name; }
117 JImageFile* jimage() const { return NULL; }
118 ClassPathZipEntry(jzfile* zip, const char* zip_name, bool is_boot_append);
119 virtual ~ClassPathZipEntry();
120 u1* open_entry(const char* name, jint* filesize, bool nul_terminate, TRAPS);
121 u1* open_versioned_entry(const char* name, jint* filesize, TRAPS) NOT_CDS_RETURN_(NULL);
122 ClassFileStream* open_stream(const char* name, TRAPS);
123 void contents_do(void f(const char* name, void* context), void* context);
124 bool is_multiple_versioned(TRAPS) NOT_CDS_RETURN_(false);
125 // Debugging
126 NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);)
127 };
128
129
130 // For java image files
131 class ClassPathImageEntry: public ClassPathEntry {
132 private:
133 JImageFile* _jimage;
134 const char* _name;
135 public:
136 bool is_jrt();
137 bool is_jar_file() const { return false; }
138 bool is_open() const { return _jimage != NULL; }
139 const char* name() const { return _name == NULL ? "" : _name; }
140 JImageFile* jimage() const { return _jimage; }
141 ClassPathImageEntry(JImageFile* jimage, const char* name);
142 virtual ~ClassPathImageEntry();
143 ClassFileStream* open_stream(const char* name, TRAPS);
144
145 // Debugging
146 NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);)
147 };
148
149 // ModuleClassPathList contains a linked list of ClassPathEntry's
150 // that have been specified for a specific module. Currently,
151 // the only way to specify a module/path pair is via the --patch-module
152 // command line option.
153 class ModuleClassPathList : public CHeapObj<mtClass> {
154 private:
155 Symbol* _module_name;
156 // First and last entries of class path entries for a specific module
157 ClassPathEntry* _module_first_entry;
158 ClassPathEntry* _module_last_entry;
159 public:
160 Symbol* module_name() const { return _module_name; }
161 ClassPathEntry* module_first_entry() const { return _module_first_entry; }
162 ModuleClassPathList(Symbol* module_name);
163 ~ModuleClassPathList();
164 void add_to_list(ClassPathEntry* new_entry);
165 };
166
167 class SharedPathsMiscInfo;
168
169 class ClassLoader: AllStatic {
170 public:
171 enum ClassLoaderType {
172 BOOT_LOADER = 1, /* boot loader */
173 PLATFORM_LOADER = 2, /* PlatformClassLoader */
174 APP_LOADER = 3 /* AppClassLoader */
175 };
176 protected:
177
178 // Performance counters
179 static PerfCounter* _perf_accumulated_time;
180 static PerfCounter* _perf_classes_inited;
181 static PerfCounter* _perf_class_init_time;
182 static PerfCounter* _perf_class_init_selftime;
183 static PerfCounter* _perf_classes_verified;
184 static PerfCounter* _perf_class_verify_time;
185 static PerfCounter* _perf_class_verify_selftime;
186 static PerfCounter* _perf_classes_linked;
187 static PerfCounter* _perf_class_link_time;
188 static PerfCounter* _perf_class_link_selftime;
189 static PerfCounter* _perf_class_parse_time;
190 static PerfCounter* _perf_class_parse_selftime;
191 static PerfCounter* _perf_sys_class_lookup_time;
192 static PerfCounter* _perf_shared_classload_time;
193 static PerfCounter* _perf_sys_classload_time;
194 static PerfCounter* _perf_app_classload_time;
195 static PerfCounter* _perf_app_classload_selftime;
196 static PerfCounter* _perf_app_classload_count;
197 static PerfCounter* _perf_define_appclasses;
198 static PerfCounter* _perf_define_appclass_time;
199 static PerfCounter* _perf_define_appclass_selftime;
200 static PerfCounter* _perf_app_classfile_bytes_read;
201 static PerfCounter* _perf_sys_classfile_bytes_read;
202
203 static PerfCounter* _sync_systemLoaderLockContentionRate;
204 static PerfCounter* _sync_nonSystemLoaderLockContentionRate;
205 static PerfCounter* _sync_JVMFindLoadedClassLockFreeCounter;
206 static PerfCounter* _sync_JVMDefineClassLockFreeCounter;
207 static PerfCounter* _sync_JNIDefineClassLockFreeCounter;
208
209 static PerfCounter* _unsafe_defineClassCallCounter;
210 static PerfCounter* _isUnsyncloadClass;
211 static PerfCounter* _load_instance_class_failCounter;
212
213 // The boot class path consists of 3 ordered pieces:
214 // 1. the module/path pairs specified to --patch-module
215 // --patch-module=<module>=<file>(<pathsep><file>)*
216 // 2. the base piece
217 // [jimage | build with exploded modules]
218 // 3. boot loader append path
219 // [-Xbootclasspath/a]; [jvmti appended entries]
220 //
221 // The boot loader must obey this order when attempting
222 // to load a class.
223
224 // 1. Contains the module/path pairs specified to --patch-module
225 static GrowableArray<ModuleClassPathList*>* _patch_mod_entries;
226
227 // 2. the base piece
228 // Contains the ClassPathEntry of the modular java runtime image.
229 // If no java runtime image is present, this indicates a
230 // build with exploded modules is being used instead.
231 static ClassPathEntry* _jrt_entry;
232 static GrowableArray<ModuleClassPathList*>* _exploded_entries;
233 enum { EXPLODED_ENTRY_SIZE = 80 }; // Initial number of exploded modules
234
235 // 3. the boot loader's append path
236 // [-Xbootclasspath/a]; [jvmti appended entries]
237 // Note: boot loader append path does not support named modules.
238 static ClassPathEntry* _first_append_entry;
239 // Last entry in linked list of appended ClassPathEntry instances
240 static ClassPathEntry* _last_append_entry;
241
242 // Note: _num_entries includes the java runtime image and all
243 // the entries on the _first_append_entry linked list.
244 static int _num_entries;
245
246 // number of entries in the boot class path including the
247 // java runtime image
248 static int _num_boot_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 static PackageEntry* get_package_entry(const char* class_name, ClassLoaderData* loader_data, TRAPS);
291
292 public:
293 static jboolean decompress(void *in, u8 inSize, void *out, u8 outSize, char **pmsg);
294 static int crc32(int crc, const char* buf, int len);
295 static bool update_class_path_entry_list(const char *path,
296 bool check_for_duplicates,
297 bool is_boot_append,
298 bool throw_exception=true);
299 static void print_bootclasspath();
300
301 // Timing
302 static PerfCounter* perf_accumulated_time() { return _perf_accumulated_time; }
303 static PerfCounter* perf_classes_inited() { return _perf_classes_inited; }
304 static PerfCounter* perf_class_init_time() { return _perf_class_init_time; }
305 static PerfCounter* perf_class_init_selftime() { return _perf_class_init_selftime; }
306 static PerfCounter* perf_classes_verified() { return _perf_classes_verified; }
307 static PerfCounter* perf_class_verify_time() { return _perf_class_verify_time; }
308 static PerfCounter* perf_class_verify_selftime() { return _perf_class_verify_selftime; }
309 static PerfCounter* perf_classes_linked() { return _perf_classes_linked; }
310 static PerfCounter* perf_class_link_time() { return _perf_class_link_time; }
311 static PerfCounter* perf_class_link_selftime() { return _perf_class_link_selftime; }
312 static PerfCounter* perf_class_parse_time() { return _perf_class_parse_time; }
313 static PerfCounter* perf_class_parse_selftime() { return _perf_class_parse_selftime; }
314 static PerfCounter* perf_sys_class_lookup_time() { return _perf_sys_class_lookup_time; }
315 static PerfCounter* perf_shared_classload_time() { return _perf_shared_classload_time; }
316 static PerfCounter* perf_sys_classload_time() { return _perf_sys_classload_time; }
317 static PerfCounter* perf_app_classload_time() { return _perf_app_classload_time; }
318 static PerfCounter* perf_app_classload_selftime() { return _perf_app_classload_selftime; }
319 static PerfCounter* perf_app_classload_count() { return _perf_app_classload_count; }
320 static PerfCounter* perf_define_appclasses() { return _perf_define_appclasses; }
321 static PerfCounter* perf_define_appclass_time() { return _perf_define_appclass_time; }
322 static PerfCounter* perf_define_appclass_selftime() { return _perf_define_appclass_selftime; }
323 static PerfCounter* perf_app_classfile_bytes_read() { return _perf_app_classfile_bytes_read; }
324 static PerfCounter* perf_sys_classfile_bytes_read() { return _perf_sys_classfile_bytes_read; }
325
326 // Record how often system loader lock object is contended
327 static PerfCounter* sync_systemLoaderLockContentionRate() {
328 return _sync_systemLoaderLockContentionRate;
329 }
330
331 // Record how often non system loader lock object is contended
332 static PerfCounter* sync_nonSystemLoaderLockContentionRate() {
333 return _sync_nonSystemLoaderLockContentionRate;
334 }
335
336 // Record how many calls to JVM_FindLoadedClass w/o holding a lock
337 static PerfCounter* sync_JVMFindLoadedClassLockFreeCounter() {
338 return _sync_JVMFindLoadedClassLockFreeCounter;
339 }
340
341 // Record how many calls to JVM_DefineClass w/o holding a lock
342 static PerfCounter* sync_JVMDefineClassLockFreeCounter() {
343 return _sync_JVMDefineClassLockFreeCounter;
344 }
345
346 // Record how many calls to jni_DefineClass w/o holding a lock
347 static PerfCounter* sync_JNIDefineClassLockFreeCounter() {
348 return _sync_JNIDefineClassLockFreeCounter;
349 }
350
351 // Record how many calls to Unsafe_DefineClass
352 static PerfCounter* unsafe_defineClassCallCounter() {
353 return _unsafe_defineClassCallCounter;
354 }
355
356 // Record how many times SystemDictionary::load_instance_class call
357 // fails with linkageError when Unsyncloadclass flag is set.
358 static PerfCounter* load_instance_class_failCounter() {
359 return _load_instance_class_failCounter;
360 }
361
362 // Modular java runtime image is present vs. a build with exploded modules
363 static bool has_jrt_entry() { return (_jrt_entry != NULL); }
364 static ClassPathEntry* get_jrt_entry() { return _jrt_entry; }
365
366 // Add a module's exploded directory to the boot loader's exploded module build list
367 static void add_to_exploded_build_list(Symbol* module_name, TRAPS);
368
369 // Attempt load of individual class from either the patched or exploded modules build lists
370 static ClassFileStream* search_module_entries(const GrowableArray<ModuleClassPathList*>* const module_list,
371 const char* const class_name,
372 const char* const file_name, TRAPS);
373
374 // Load individual .class file
375 static InstanceKlass* load_class(Symbol* class_name, bool search_append_only, TRAPS);
376
377 // If the specified package has been loaded by the system, then returns
378 // the name of the directory or ZIP file that the package was loaded from.
379 // Returns null if the package was not loaded.
380 // Note: The specified name can either be the name of a class or package.
381 // If a package name is specified, then it must be "/"-separator and also
382 // end with a trailing "/".
383 static oop get_system_package(const char* name, TRAPS);
384
385 // Returns an array of Java strings representing all of the currently
386 // loaded system packages.
387 // Note: The package names returned are "/"-separated and end with a
388 // trailing "/".
389 static objArrayOop get_system_packages(TRAPS);
390
391 // Initialization
392 static void initialize();
393 static void classLoader_init2(TRAPS);
394 CDS_ONLY(static void initialize_shared_path();)
395
396 static int compute_Object_vtable();
397
398 static ClassPathEntry* classpath_entry(int n) {
399 assert(n >= 0, "sanity");
400 assert(!has_jrt_entry() || n < _num_entries, "sanity");
401 if (n == 0) {
402 assert(has_jrt_entry(), "No class path entry at 0 for exploded module builds");
403 return ClassLoader::_jrt_entry;
404 } else {
405 // The java runtime image is always the first entry
406 // in the FileMapInfo::_classpath_entry_table. Even though
407 // the _jrt_entry is not included in the _first_append_entry
408 // linked list, it must be accounted for when comparing the
409 // class path vs. the shared archive class path.
410 ClassPathEntry* e = ClassLoader::_first_append_entry;
411 while (--n >= 1) {
412 assert(e != NULL, "Not that many classpath entries.");
413 e = e->next();
414 }
415 return e;
416 }
417 }
418
419 static int number_of_classpath_entries() {
420 return _num_entries;
421 }
422
423 static bool is_in_patch_mod_entries(Symbol* module_name);
424
425 #if INCLUDE_CDS
426 // Sharing dump and restore
427
428 static void check_shared_classpath(const char *path);
429 static void finalize_shared_paths_misc_info();
430 static int get_shared_paths_misc_info_size();
431 static void* get_shared_paths_misc_info();
432 static bool check_shared_paths_misc_info(void* info, int size);
433 static void exit_with_path_failure(const char* error, const char* message);
434
435 static void record_shared_class_loader_type(InstanceKlass* ik, const ClassFileStream* stream);
436 #endif
437 static JImageLocationRef jimage_find_resource(JImageFile* jf, const char* module_name,
438 const char* file_name, jlong &size);
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_append_entry(const char* name);
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