1 /*
2 * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_CLASSFILE_CLASSLOADER_HPP
26 #define SHARE_CLASSFILE_CLASSLOADER_HPP
27
28 #include "jimage.hpp"
29 #include "runtime/arguments.hpp"
30 #include "runtime/handles.hpp"
31 #include "runtime/perfData.hpp"
32 #include "utilities/exceptions.hpp"
33 #include "utilities/macros.hpp"
34
35 // The VM class loader.
36 #include <sys/stat.h>
37
38 // Name of boot "modules" image
39 #define MODULES_IMAGE_NAME "modules"
40
41 // Class path entry (directory or zip file)
42
43 class JImageFile;
44 class ClassFileStream;
45 class PackageEntry;
46 template <typename T> class GrowableArray;
47
48 class ClassPathEntry : public CHeapObj<mtClass> {
49 private:
50 ClassPathEntry* volatile _next;
51 protected:
52 const char* copy_path(const char*path);
53 public:
54 ClassPathEntry* next() const;
55 virtual ~ClassPathEntry() {}
56 void set_next(ClassPathEntry* next);
57 virtual bool is_modules_image() const { return false; }
58 virtual bool is_jar_file() const { return false; }
59 // Is this entry created from the "Class-path" attribute from a JAR Manifest?
60 virtual bool from_class_path_attr() const { return false; }
61 virtual const char* name() const = 0;
62 virtual JImageFile* jimage() const { return NULL; }
63 virtual void close_jimage() {}
64 // Constructor
65 ClassPathEntry() : _next(NULL) {}
66 // Attempt to locate file_name through this class path entry.
67 // Returns a class file parsing stream if successfull.
68 virtual ClassFileStream* open_stream(const char* name, TRAPS) = 0;
69 // Open the stream for a specific class loader
70 virtual ClassFileStream* open_stream_for_loader(const char* name, ClassLoaderData* loader_data, TRAPS) {
71 return open_stream(name, THREAD);
72 }
73 };
74
75 class ClassPathDirEntry: public ClassPathEntry {
76 private:
77 const char* _dir; // Name of directory
78 public:
79 const char* name() const { return _dir; }
80 ClassPathDirEntry(const char* dir) {
81 _dir = copy_path(dir);
82 }
83 virtual ~ClassPathDirEntry() {}
84 ClassFileStream* open_stream(const char* name, TRAPS);
85 };
86
87 // Type definitions for zip file and zip file entry
88 typedef void* jzfile;
89 typedef struct {
90 char *name; /* entry name */
91 jlong time; /* modification time */
92 jlong size; /* size of uncompressed data */
93 jlong csize; /* size of compressed data (zero if uncompressed) */
94 jint crc; /* crc of uncompressed data */
95 char *comment; /* optional zip file comment */
96 jbyte *extra; /* optional extra data */
97 jlong pos; /* position of LOC header (if negative) or data */
98 } jzentry;
99
100 class ClassPathZipEntry: public ClassPathEntry {
101 private:
102 jzfile* _zip; // The zip archive
103 const char* _zip_name; // Name of zip archive
104 bool _from_class_path_attr; // From the "Class-path" attribute of a jar file
105 public:
106 bool is_jar_file() const { return true; }
107 bool from_class_path_attr() const { return _from_class_path_attr; }
108 const char* name() const { return _zip_name; }
109 ClassPathZipEntry(jzfile* zip, const char* zip_name, bool is_boot_append, bool from_class_path_attr);
110 virtual ~ClassPathZipEntry();
111 u1* open_entry(const char* name, jint* filesize, bool nul_terminate, TRAPS);
112 ClassFileStream* open_stream(const char* name, TRAPS);
113 void contents_do(void f(const char* name, void* context), void* context);
114 };
115
116
117 // For java image files
118 class ClassPathImageEntry: public ClassPathEntry {
119 private:
120 JImageFile* _jimage;
121 const char* _name;
122 DEBUG_ONLY(static ClassPathImageEntry* _singleton;)
123 public:
124 bool is_modules_image() const;
125 bool is_open() const { return _jimage != NULL; }
126 const char* name() const { return _name == NULL ? "" : _name; }
127 JImageFile* jimage() const { return _jimage; }
128 void close_jimage();
129 ClassPathImageEntry(JImageFile* jimage, const char* name);
130 virtual ~ClassPathImageEntry();
131 ClassFileStream* open_stream(const char* name, TRAPS);
132 ClassFileStream* open_stream_for_loader(const char* name, ClassLoaderData* loader_data, TRAPS);
133 };
134
135 // ModuleClassPathList contains a linked list of ClassPathEntry's
136 // that have been specified for a specific module. Currently,
137 // the only way to specify a module/path pair is via the --patch-module
138 // command line option.
139 class ModuleClassPathList : public CHeapObj<mtClass> {
140 private:
141 Symbol* _module_name;
142 // First and last entries of class path entries for a specific module
143 ClassPathEntry* _module_first_entry;
144 ClassPathEntry* _module_last_entry;
145 public:
146 Symbol* module_name() const { return _module_name; }
147 ClassPathEntry* module_first_entry() const { return _module_first_entry; }
148 ModuleClassPathList(Symbol* module_name);
149 ~ModuleClassPathList();
150 void add_to_list(ClassPathEntry* new_entry);
151 };
152
153 class ClassLoader: AllStatic {
154 public:
155 enum ClassLoaderType {
156 BOOT_LOADER = 1, /* boot loader */
157 PLATFORM_LOADER = 2, /* PlatformClassLoader */
158 APP_LOADER = 3 /* AppClassLoader */
159 };
160 protected:
161
162 // Performance counters
163 static PerfCounter* _perf_accumulated_time;
164 static PerfCounter* _perf_classes_inited;
165 static PerfCounter* _perf_class_init_time;
166 static PerfCounter* _perf_class_init_selftime;
167 static PerfCounter* _perf_classes_verified;
168 static PerfCounter* _perf_class_verify_time;
169 static PerfCounter* _perf_class_verify_selftime;
170 static PerfCounter* _perf_classes_linked;
171 static PerfCounter* _perf_class_link_time;
172 static PerfCounter* _perf_class_link_selftime;
173 static PerfCounter* _perf_class_parse_time;
174 static PerfCounter* _perf_class_parse_selftime;
175 static PerfCounter* _perf_sys_class_lookup_time;
176 static PerfCounter* _perf_shared_classload_time;
177 static PerfCounter* _perf_sys_classload_time;
178 static PerfCounter* _perf_app_classload_time;
179 static PerfCounter* _perf_app_classload_selftime;
180 static PerfCounter* _perf_app_classload_count;
181 static PerfCounter* _perf_define_appclasses;
182 static PerfCounter* _perf_define_appclass_time;
183 static PerfCounter* _perf_define_appclass_selftime;
184 static PerfCounter* _perf_app_classfile_bytes_read;
185 static PerfCounter* _perf_sys_classfile_bytes_read;
186
187 static PerfCounter* _sync_systemLoaderLockContentionRate;
188 static PerfCounter* _sync_nonSystemLoaderLockContentionRate;
189 static PerfCounter* _sync_JVMFindLoadedClassLockFreeCounter;
190 static PerfCounter* _sync_JVMDefineClassLockFreeCounter;
191 static PerfCounter* _sync_JNIDefineClassLockFreeCounter;
192
193 static PerfCounter* _unsafe_defineClassCallCounter;
194
195 // The boot class path consists of 3 ordered pieces:
196 // 1. the module/path pairs specified to --patch-module
197 // --patch-module=<module>=<file>(<pathsep><file>)*
198 // 2. the base piece
199 // [jimage | build with exploded modules]
200 // 3. boot loader append path
201 // [-Xbootclasspath/a]; [jvmti appended entries]
202 //
203 // The boot loader must obey this order when attempting
204 // to load a class.
205
206 // 1. Contains the module/path pairs specified to --patch-module
207 static GrowableArray<ModuleClassPathList*>* _patch_mod_entries;
208
209 // 2. the base piece
210 // Contains the ClassPathEntry of the modular java runtime image.
211 // If no java runtime image is present, this indicates a
212 // build with exploded modules is being used instead.
213 static ClassPathEntry* _jrt_entry;
214 static GrowableArray<ModuleClassPathList*>* _exploded_entries;
215 enum { EXPLODED_ENTRY_SIZE = 80 }; // Initial number of exploded modules
216
217 // 3. the boot loader's append path
218 // [-Xbootclasspath/a]; [jvmti appended entries]
219 // Note: boot loader append path does not support named modules.
220 static ClassPathEntry* _first_append_entry;
221 // Last entry in linked list of appended ClassPathEntry instances
222 static ClassPathEntry* _last_append_entry;
223
224 // Info used by CDS
225 CDS_ONLY(static ClassPathEntry* _app_classpath_entries;)
226 CDS_ONLY(static ClassPathEntry* _last_app_classpath_entry;)
227 CDS_ONLY(static ClassPathEntry* _module_path_entries;)
228 CDS_ONLY(static ClassPathEntry* _last_module_path_entry;)
229 CDS_ONLY(static void setup_app_search_path(const char* class_path);)
230 CDS_ONLY(static void setup_module_search_path(const char* path, TRAPS);)
231 static void add_to_app_classpath_entries(const char* path,
232 ClassPathEntry* entry,
233 bool check_for_duplicates);
234 CDS_ONLY(static void add_to_module_path_entries(const char* path,
235 ClassPathEntry* entry);)
236 public:
237 CDS_ONLY(static ClassPathEntry* app_classpath_entries() {return _app_classpath_entries;})
238 CDS_ONLY(static ClassPathEntry* module_path_entries() {return _module_path_entries;})
239
240 protected:
241 // Initialization:
242 // - setup the boot loader's system class path
243 // - setup the boot loader's patch mod entries, if present
244 // - create the ModuleEntry for java.base
245 static void setup_bootstrap_search_path();
246 static void setup_boot_search_path(const char *class_path);
247 static void setup_patch_mod_entries();
248 static void create_javabase();
249
250 static void load_zip_library();
251 static void load_jimage_library();
252
253 public:
254 static ClassPathEntry* create_class_path_entry(const char *path, const struct stat* st,
255 bool throw_exception,
256 bool is_boot_append,
257 bool from_class_path_attr, TRAPS);
258
259 // If the package for the fully qualified class name is in the boot
260 // loader's package entry table then add_package() sets the classpath_index
261 // field so that get_system_package() will know to return a non-null value
262 // for the package's location. And, so that the package will be added to
263 // the list of packages returned by get_system_packages().
264 // For packages whose classes are loaded from the boot loader class path, the
265 // classpath_index indicates which entry on the boot loader class path.
266 static bool add_package(const char *fullq_class_name, s2 classpath_index, TRAPS);
267
268 // Canonicalizes path names, so strcmp will work properly. This is mainly
269 // to avoid confusing the zip library
270 static bool get_canonical_path(const char* orig, char* out, int len);
271 static const char* file_name_for_class_name(const char* class_name,
272 int class_name_len);
273 static PackageEntry* get_package_entry(const char* class_name, ClassLoaderData* loader_data, TRAPS);
274
275 public:
276 static jboolean decompress(void *in, u8 inSize, void *out, u8 outSize, char **pmsg);
277 static int crc32(int crc, const char* buf, int len);
278 static bool update_class_path_entry_list(const char *path,
279 bool check_for_duplicates,
280 bool is_boot_append,
281 bool from_class_path_attr,
282 bool throw_exception=true);
283 CDS_ONLY(static void update_module_path_entry_list(const char *path, TRAPS);)
284 static void print_bootclasspath();
285
286 // Timing
287 static PerfCounter* perf_accumulated_time() { return _perf_accumulated_time; }
288 static PerfCounter* perf_classes_inited() { return _perf_classes_inited; }
289 static PerfCounter* perf_class_init_time() { return _perf_class_init_time; }
290 static PerfCounter* perf_class_init_selftime() { return _perf_class_init_selftime; }
291 static PerfCounter* perf_classes_verified() { return _perf_classes_verified; }
292 static PerfCounter* perf_class_verify_time() { return _perf_class_verify_time; }
293 static PerfCounter* perf_class_verify_selftime() { return _perf_class_verify_selftime; }
294 static PerfCounter* perf_classes_linked() { return _perf_classes_linked; }
295 static PerfCounter* perf_class_link_time() { return _perf_class_link_time; }
296 static PerfCounter* perf_class_link_selftime() { return _perf_class_link_selftime; }
297 static PerfCounter* perf_class_parse_time() { return _perf_class_parse_time; }
298 static PerfCounter* perf_class_parse_selftime() { return _perf_class_parse_selftime; }
299 static PerfCounter* perf_sys_class_lookup_time() { return _perf_sys_class_lookup_time; }
300 static PerfCounter* perf_shared_classload_time() { return _perf_shared_classload_time; }
301 static PerfCounter* perf_sys_classload_time() { return _perf_sys_classload_time; }
302 static PerfCounter* perf_app_classload_time() { return _perf_app_classload_time; }
303 static PerfCounter* perf_app_classload_selftime() { return _perf_app_classload_selftime; }
304 static PerfCounter* perf_app_classload_count() { return _perf_app_classload_count; }
305 static PerfCounter* perf_define_appclasses() { return _perf_define_appclasses; }
306 static PerfCounter* perf_define_appclass_time() { return _perf_define_appclass_time; }
307 static PerfCounter* perf_define_appclass_selftime() { return _perf_define_appclass_selftime; }
308 static PerfCounter* perf_app_classfile_bytes_read() { return _perf_app_classfile_bytes_read; }
309 static PerfCounter* perf_sys_classfile_bytes_read() { return _perf_sys_classfile_bytes_read; }
310
311 // Record how often system loader lock object is contended
312 static PerfCounter* sync_systemLoaderLockContentionRate() {
313 return _sync_systemLoaderLockContentionRate;
314 }
315
316 // Record how often non system loader lock object is contended
317 static PerfCounter* sync_nonSystemLoaderLockContentionRate() {
318 return _sync_nonSystemLoaderLockContentionRate;
319 }
320
321 // Record how many calls to JVM_FindLoadedClass w/o holding a lock
322 static PerfCounter* sync_JVMFindLoadedClassLockFreeCounter() {
323 return _sync_JVMFindLoadedClassLockFreeCounter;
324 }
325
326 // Record how many calls to JVM_DefineClass w/o holding a lock
327 static PerfCounter* sync_JVMDefineClassLockFreeCounter() {
328 return _sync_JVMDefineClassLockFreeCounter;
329 }
330
331 // Record how many calls to jni_DefineClass w/o holding a lock
332 static PerfCounter* sync_JNIDefineClassLockFreeCounter() {
333 return _sync_JNIDefineClassLockFreeCounter;
334 }
335
336 // Record how many calls to Unsafe_DefineClass
337 static PerfCounter* unsafe_defineClassCallCounter() {
338 return _unsafe_defineClassCallCounter;
339 }
340
341 // Modular java runtime image is present vs. a build with exploded modules
342 static bool has_jrt_entry() { return (_jrt_entry != NULL); }
343 static ClassPathEntry* get_jrt_entry() { return _jrt_entry; }
344 static void close_jrt_image();
345
346 // Add a module's exploded directory to the boot loader's exploded module build list
347 static void add_to_exploded_build_list(Symbol* module_name, TRAPS);
348
349 // Attempt load of individual class from either the patched or exploded modules build lists
350 static ClassFileStream* search_module_entries(const GrowableArray<ModuleClassPathList*>* const module_list,
351 const char* const class_name,
352 const char* const file_name, TRAPS);
353
354 // Load individual .class file
355 static InstanceKlass* load_class(Symbol* class_name, bool search_append_only, TRAPS);
356
357 // If the specified package has been loaded by the system, then returns
358 // the name of the directory or ZIP file that the package was loaded from.
359 // Returns null if the package was not loaded.
360 // Note: The specified name can either be the name of a class or package.
361 // If a package name is specified, then it must be "/"-separator and also
362 // end with a trailing "/".
363 static oop get_system_package(const char* name, TRAPS);
364
365 // Returns an array of Java strings representing all of the currently
366 // loaded system packages.
367 // Note: The package names returned are "/"-separated and end with a
368 // trailing "/".
369 static objArrayOop get_system_packages(TRAPS);
370
371 // Initialization
372 static void initialize();
373 static void classLoader_init2(TRAPS);
374 CDS_ONLY(static void initialize_shared_path();)
375 CDS_ONLY(static void initialize_module_path(TRAPS);)
376
377 static int compute_Object_vtable();
378
379 static ClassPathEntry* classpath_entry(int n);
380
381 static bool is_in_patch_mod_entries(Symbol* module_name);
382
383 #if INCLUDE_CDS
384 // Sharing dump and restore
385
386 // Helper function used by CDS code to get the number of boot classpath
387 // entries during shared classpath setup time.
388 static int num_boot_classpath_entries();
389
390 static ClassPathEntry* get_next_boot_classpath_entry(ClassPathEntry* e);
391
392 // Helper function used by CDS code to get the number of app classpath
393 // entries during shared classpath setup time.
394 static int num_app_classpath_entries();
395
396 // Helper function used by CDS code to get the number of module path
397 // entries during shared classpath setup time.
398 static int num_module_path_entries() {
399 assert(Arguments::is_dumping_archive(),
400 "Should only be called at CDS dump time");
401 int num_entries = 0;
402 ClassPathEntry* e= ClassLoader::_module_path_entries;
403 while (e != NULL) {
404 num_entries ++;
405 e = e->next();
406 }
407 return num_entries;
408 }
409 static void exit_with_path_failure(const char* error, const char* message);
410 static char* skip_uri_protocol(char* source);
411 static void record_result(InstanceKlass* ik, const ClassFileStream* stream, TRAPS);
412 #endif
413 static JImageLocationRef jimage_find_resource(JImageFile* jf, const char* module_name,
414 const char* file_name, jlong &size);
415
416 static void trace_class_path(const char* msg, const char* name = NULL);
417
418 // VM monitoring and management support
419 static jlong classloader_time_ms();
420 static jlong class_method_total_size();
421 static jlong class_init_count();
422 static jlong class_init_time_ms();
423 static jlong class_verify_time_ms();
424 static jlong class_link_count();
425 static jlong class_link_time_ms();
426
427 // indicates if class path already contains a entry (exact match by name)
428 static bool contains_append_entry(const char* name);
429
430 // adds a class path to the boot append entries
431 static void add_to_boot_append_entries(ClassPathEntry* new_entry);
432
433 // creates a class path zip entry (returns NULL if JAR file cannot be opened)
434 static ClassPathZipEntry* create_class_path_zip_entry(const char *apath, bool is_boot_append);
435
436 static bool string_ends_with(const char* str, const char* str_to_find);
437
438 // obtain package name from a fully qualified class name
439 // *bad_class_name is set to true if there's a problem with parsing class_name, to
440 // distinguish from a class_name with no package name, as both cases have a NULL return value
441 static const char* package_from_name(const char* const class_name, bool* bad_class_name = NULL);
442
443 // Debugging
444 static void verify() PRODUCT_RETURN;
445 };
446
447 // PerfClassTraceTime is used to measure time for class loading related events.
448 // This class tracks cumulative time and exclusive time for specific event types.
449 // During the execution of one event, other event types (e.g. class loading and
450 // resolution) as well as recursive calls of the same event type could happen.
451 // Only one elapsed timer (cumulative) and one thread-local self timer (exclusive)
452 // (i.e. only one event type) are active at a time even multiple PerfClassTraceTime
453 // instances have been created as multiple events are happening.
454 class PerfClassTraceTime {
455 public:
456 enum {
457 CLASS_LOAD = 0,
458 PARSE_CLASS = 1,
459 CLASS_LINK = 2,
460 CLASS_VERIFY = 3,
461 CLASS_CLINIT = 4,
462 DEFINE_CLASS = 5,
463 EVENT_TYPE_COUNT = 6
464 };
465 protected:
466 // _t tracks time from initialization to destruction of this timer instance
467 // including time for all other event types, and recursive calls of this type.
468 // When a timer is called recursively, the elapsedTimer _t would not be used.
469 elapsedTimer _t;
470 PerfLongCounter* _timep;
471 PerfLongCounter* _selftimep;
472 PerfLongCounter* _eventp;
473 // pointer to thread-local recursion counter and timer array
474 // The thread_local timers track cumulative time for specific event types
475 // exclusive of time for other event types, but including recursive calls
476 // of the same type.
477 int* _recursion_counters;
478 elapsedTimer* _timers;
479 int _event_type;
480 int _prev_active_event;
481
482 public:
483
484 inline PerfClassTraceTime(PerfLongCounter* timep, /* counter incremented with inclusive time */
485 PerfLongCounter* selftimep, /* counter incremented with exclusive time */
486 PerfLongCounter* eventp, /* event counter */
487 int* recursion_counters, /* thread-local recursion counter array */
488 elapsedTimer* timers, /* thread-local timer array */
489 int type /* event type */ ) :
490 _timep(timep), _selftimep(selftimep), _eventp(eventp), _recursion_counters(recursion_counters), _timers(timers), _event_type(type) {
491 initialize();
492 }
493
494 inline PerfClassTraceTime(PerfLongCounter* timep, /* counter incremented with inclusive time */
495 elapsedTimer* timers, /* thread-local timer array */
496 int type /* event type */ ) :
497 _timep(timep), _selftimep(NULL), _eventp(NULL), _recursion_counters(NULL), _timers(timers), _event_type(type) {
498 initialize();
499 }
500
501 inline void suspend() { _t.stop(); _timers[_event_type].stop(); }
502 inline void resume() { _t.start(); _timers[_event_type].start(); }
503
504 ~PerfClassTraceTime();
505 void initialize();
506 };
507
508 #endif // SHARE_CLASSFILE_CLASSLOADER_HPP