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