1 /*
2 * Copyright (c) 1997, 2020, 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_sys_class_lookup_time;
174 static PerfCounter* _perf_shared_classload_time;
175 static PerfCounter* _perf_sys_classload_time;
176 static PerfCounter* _perf_app_classload_time;
177 static PerfCounter* _perf_app_classload_selftime;
178 static PerfCounter* _perf_app_classload_count;
179 static PerfCounter* _perf_define_appclasses;
180 static PerfCounter* _perf_define_appclass_time;
181 static PerfCounter* _perf_define_appclass_selftime;
182 static PerfCounter* _perf_app_classfile_bytes_read;
183 static PerfCounter* _perf_sys_classfile_bytes_read;
184
185 static PerfCounter* _sync_systemLoaderLockContentionRate;
186 static PerfCounter* _sync_nonSystemLoaderLockContentionRate;
187 static PerfCounter* _sync_JVMFindLoadedClassLockFreeCounter;
188 static PerfCounter* _sync_JVMDefineClassLockFreeCounter;
189 static PerfCounter* _sync_JNIDefineClassLockFreeCounter;
190
191 static PerfCounter* _unsafe_defineClassCallCounter;
192
193 // The boot class path consists of 3 ordered pieces:
194 // 1. the module/path pairs specified to --patch-module
195 // --patch-module=<module>=<file>(<pathsep><file>)*
196 // 2. the base piece
197 // [jimage | build with exploded modules]
198 // 3. boot loader append path
199 // [-Xbootclasspath/a]; [jvmti appended entries]
200 //
201 // The boot loader must obey this order when attempting
202 // to load a class.
203
204 // 1. Contains the module/path pairs specified to --patch-module
205 static GrowableArray<ModuleClassPathList*>* _patch_mod_entries;
206
207 // 2. the base piece
208 // Contains the ClassPathEntry of the modular java runtime image.
209 // If no java runtime image is present, this indicates a
210 // build with exploded modules is being used instead.
211 static ClassPathEntry* _jrt_entry;
212 static GrowableArray<ModuleClassPathList*>* _exploded_entries;
213 enum { EXPLODED_ENTRY_SIZE = 80 }; // Initial number of exploded modules
214
215 // 3. the boot loader's append path
216 // [-Xbootclasspath/a]; [jvmti appended entries]
217 // Note: boot loader append path does not support named modules.
218 static ClassPathEntry* _first_append_entry;
219 // Last entry in linked list of appended ClassPathEntry instances
220 static ClassPathEntry* _last_append_entry;
221
222 // Info used by CDS
223 CDS_ONLY(static ClassPathEntry* _app_classpath_entries;)
224 CDS_ONLY(static ClassPathEntry* _last_app_classpath_entry;)
225 CDS_ONLY(static ClassPathEntry* _module_path_entries;)
226 CDS_ONLY(static ClassPathEntry* _last_module_path_entry;)
227 CDS_ONLY(static void setup_app_search_path(const char* class_path);)
228 CDS_ONLY(static void setup_module_search_path(const char* path, TRAPS);)
229 static void add_to_app_classpath_entries(const char* path,
230 ClassPathEntry* entry,
231 bool check_for_duplicates);
232 CDS_ONLY(static void add_to_module_path_entries(const char* path,
233 ClassPathEntry* entry);)
234 public:
235 CDS_ONLY(static ClassPathEntry* app_classpath_entries() {return _app_classpath_entries;})
236 CDS_ONLY(static ClassPathEntry* module_path_entries() {return _module_path_entries;})
237
238 static bool has_bootclasspath_append() { return _first_append_entry != NULL; }
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* dll_lookup(void* lib, const char* name, const char* path);
251 static void load_java_library();
252 static void load_zip_library();
253 static void load_jimage_library();
254
255 private:
256 static int _libzip_loaded; // used to sync loading zip.
257 static void release_load_zip_library();
258 static inline void load_zip_library_if_needed();
259
260 public:
261 static ClassPathEntry* create_class_path_entry(const char *path, const struct stat* st,
262 bool throw_exception,
263 bool is_boot_append,
264 bool from_class_path_attr, TRAPS);
265
266 // Canonicalizes path names, so strcmp will work properly. This is mainly
267 // to avoid confusing the zip library
268 static bool get_canonical_path(const char* orig, char* out, int len);
269 static const char* file_name_for_class_name(const char* class_name,
270 int class_name_len);
271 static PackageEntry* get_package_entry(Symbol* pkg_name, ClassLoaderData* loader_data);
272 static int crc32(int crc, const char* buf, int len);
273 static bool update_class_path_entry_list(const char *path,
274 bool check_for_duplicates,
275 bool is_boot_append,
276 bool from_class_path_attr,
277 bool throw_exception=true);
278 CDS_ONLY(static void update_module_path_entry_list(const char *path, TRAPS);)
279 static void print_bootclasspath();
280
281 // Timing
282 static PerfCounter* perf_accumulated_time() { return _perf_accumulated_time; }
283 static PerfCounter* perf_classes_inited() { return _perf_classes_inited; }
284 static PerfCounter* perf_class_init_time() { return _perf_class_init_time; }
285 static PerfCounter* perf_class_init_selftime() { return _perf_class_init_selftime; }
286 static PerfCounter* perf_classes_verified() { return _perf_classes_verified; }
287 static PerfCounter* perf_class_verify_time() { return _perf_class_verify_time; }
288 static PerfCounter* perf_class_verify_selftime() { return _perf_class_verify_selftime; }
289 static PerfCounter* perf_classes_linked() { return _perf_classes_linked; }
290 static PerfCounter* perf_class_link_time() { return _perf_class_link_time; }
291 static PerfCounter* perf_class_link_selftime() { return _perf_class_link_selftime; }
292 static PerfCounter* perf_sys_class_lookup_time() { return _perf_sys_class_lookup_time; }
293 static PerfCounter* perf_shared_classload_time() { return _perf_shared_classload_time; }
294 static PerfCounter* perf_sys_classload_time() { return _perf_sys_classload_time; }
295 static PerfCounter* perf_app_classload_time() { return _perf_app_classload_time; }
296 static PerfCounter* perf_app_classload_selftime() { return _perf_app_classload_selftime; }
297 static PerfCounter* perf_app_classload_count() { return _perf_app_classload_count; }
298 static PerfCounter* perf_define_appclasses() { return _perf_define_appclasses; }
299 static PerfCounter* perf_define_appclass_time() { return _perf_define_appclass_time; }
300 static PerfCounter* perf_define_appclass_selftime() { return _perf_define_appclass_selftime; }
301 static PerfCounter* perf_app_classfile_bytes_read() { return _perf_app_classfile_bytes_read; }
302 static PerfCounter* perf_sys_classfile_bytes_read() { return _perf_sys_classfile_bytes_read; }
303
304 // Record how often system loader lock object is contended
305 static PerfCounter* sync_systemLoaderLockContentionRate() {
306 return _sync_systemLoaderLockContentionRate;
307 }
308
309 // Record how often non system loader lock object is contended
310 static PerfCounter* sync_nonSystemLoaderLockContentionRate() {
311 return _sync_nonSystemLoaderLockContentionRate;
312 }
313
314 // Record how many calls to JVM_FindLoadedClass w/o holding a lock
315 static PerfCounter* sync_JVMFindLoadedClassLockFreeCounter() {
316 return _sync_JVMFindLoadedClassLockFreeCounter;
317 }
318
319 // Record how many calls to JVM_DefineClass w/o holding a lock
320 static PerfCounter* sync_JVMDefineClassLockFreeCounter() {
321 return _sync_JVMDefineClassLockFreeCounter;
322 }
323
324 // Record how many calls to jni_DefineClass w/o holding a lock
325 static PerfCounter* sync_JNIDefineClassLockFreeCounter() {
326 return _sync_JNIDefineClassLockFreeCounter;
327 }
328
329 // Record how many calls to Unsafe_DefineClass
330 static PerfCounter* unsafe_defineClassCallCounter() {
331 return _unsafe_defineClassCallCounter;
332 }
333
334 // Modular java runtime image is present vs. a build with exploded modules
335 static bool has_jrt_entry() { return (_jrt_entry != NULL); }
336 static ClassPathEntry* get_jrt_entry() { return _jrt_entry; }
337 static void close_jrt_image();
338
339 // Add a module's exploded directory to the boot loader's exploded module build list
340 static void add_to_exploded_build_list(Symbol* module_name, TRAPS);
341
342 // Attempt load of individual class from either the patched or exploded modules build lists
343 static ClassFileStream* search_module_entries(const GrowableArray<ModuleClassPathList*>* const module_list,
344 const char* const class_name,
345 const char* const file_name, TRAPS);
346
347 // Load individual .class file
348 static InstanceKlass* load_class(Symbol* class_name, bool search_append_only, TRAPS);
349
350 // If the specified package has been loaded by the system, then returns
351 // the name of the directory or ZIP file that the package was loaded from.
352 // Returns null if the package was not loaded.
353 // Note: The specified name can either be the name of a class or package.
354 // If a package name is specified, then it must be "/"-separator and also
355 // end with a trailing "/".
356 static oop get_system_package(const char* name, TRAPS);
357
358 // Returns an array of Java strings representing all of the currently
359 // loaded system packages.
360 // Note: The package names returned are "/"-separated and end with a
361 // trailing "/".
362 static objArrayOop get_system_packages(TRAPS);
363
364 // Initialization
365 static void initialize();
366 static void classLoader_init2(TRAPS);
367 CDS_ONLY(static void initialize_shared_path();)
368 CDS_ONLY(static void initialize_module_path(TRAPS);)
369
370 static int compute_Object_vtable();
371
372 static ClassPathEntry* classpath_entry(int n);
373
374 static bool is_in_patch_mod_entries(Symbol* module_name);
375
376 #if INCLUDE_CDS
377 // Sharing dump and restore
378
379 // Helper function used by CDS code to get the number of boot classpath
380 // entries during shared classpath setup time.
381 static int num_boot_classpath_entries();
382
383 static ClassPathEntry* get_next_boot_classpath_entry(ClassPathEntry* e);
384
385 // Helper function used by CDS code to get the number of app classpath
386 // entries during shared classpath setup time.
387 static int num_app_classpath_entries();
388
389 // Helper function used by CDS code to get the number of module path
390 // entries during shared classpath setup time.
391 static int num_module_path_entries() {
392 Arguments::assert_is_dumping_archive();
393 int num_entries = 0;
394 ClassPathEntry* e= ClassLoader::_module_path_entries;
395 while (e != NULL) {
396 num_entries ++;
397 e = e->next();
398 }
399 return num_entries;
400 }
401 static void exit_with_path_failure(const char* error, const char* message);
402 static char* skip_uri_protocol(char* source);
403 static void record_result(InstanceKlass* ik, const ClassFileStream* stream, TRAPS);
404 #endif
405
406 static char* lookup_vm_options();
407
408 static JImageLocationRef jimage_find_resource(JImageFile* jf, const char* module_name,
409 const char* file_name, jlong &size);
410
411 static void trace_class_path(const char* msg, const char* name = NULL);
412
413 // VM monitoring and management support
414 static jlong classloader_time_ms();
415 static jlong class_method_total_size();
416 static jlong class_init_count();
417 static jlong class_init_time_ms();
418 static jlong class_verify_time_ms();
419 static jlong class_link_count();
420 static jlong class_link_time_ms();
421
422 // indicates if class path already contains a entry (exact match by name)
423 static bool contains_append_entry(const char* name);
424
425 // adds a class path to the boot append entries
426 static void add_to_boot_append_entries(ClassPathEntry* new_entry);
427
428 // creates a class path zip entry (returns NULL if JAR file cannot be opened)
429 static ClassPathZipEntry* create_class_path_zip_entry(const char *apath, bool is_boot_append);
430
431 static bool string_ends_with(const char* str, const char* str_to_find);
432
433 // Extract package name from a fully qualified class name
434 // *bad_class_name is set to true if there's a problem with parsing class_name, to
435 // distinguish from a class_name with no package name, as both cases have a NULL return value
436 static Symbol* package_from_class_name(const Symbol* class_name, bool* bad_class_name = NULL);
437
438 // Debugging
439 static void verify() PRODUCT_RETURN;
440 };
441
442 // PerfClassTraceTime is used to measure time for class loading related events.
443 // This class tracks cumulative time and exclusive time for specific event types.
444 // During the execution of one event, other event types (e.g. class loading and
445 // resolution) as well as recursive calls of the same event type could happen.
446 // Only one elapsed timer (cumulative) and one thread-local self timer (exclusive)
447 // (i.e. only one event type) are active at a time even multiple PerfClassTraceTime
448 // instances have been created as multiple events are happening.
449 class PerfClassTraceTime {
450 public:
451 enum {
452 CLASS_LOAD = 0,
453 PARSE_CLASS = 1,
454 CLASS_LINK = 2,
455 CLASS_VERIFY = 3,
456 CLASS_CLINIT = 4,
457 DEFINE_CLASS = 5,
458 EVENT_TYPE_COUNT = 6
459 };
460 protected:
461 // _t tracks time from initialization to destruction of this timer instance
462 // including time for all other event types, and recursive calls of this type.
463 // When a timer is called recursively, the elapsedTimer _t would not be used.
464 elapsedTimer _t;
465 PerfLongCounter* _timep;
466 PerfLongCounter* _selftimep;
467 PerfLongCounter* _eventp;
468 // pointer to thread-local recursion counter and timer array
469 // The thread_local timers track cumulative time for specific event types
470 // exclusive of time for other event types, but including recursive calls
471 // of the same type.
472 int* _recursion_counters;
473 elapsedTimer* _timers;
474 int _event_type;
475 int _prev_active_event;
476
477 public:
478
479 inline PerfClassTraceTime(PerfLongCounter* timep, /* counter incremented with inclusive time */
480 PerfLongCounter* selftimep, /* counter incremented with exclusive time */
481 PerfLongCounter* eventp, /* event counter */
482 int* recursion_counters, /* thread-local recursion counter array */
483 elapsedTimer* timers, /* thread-local timer array */
484 int type /* event type */ ) :
485 _timep(timep), _selftimep(selftimep), _eventp(eventp), _recursion_counters(recursion_counters), _timers(timers), _event_type(type) {
486 initialize();
487 }
488
489 inline PerfClassTraceTime(PerfLongCounter* timep, /* counter incremented with inclusive time */
490 elapsedTimer* timers, /* thread-local timer array */
491 int type /* event type */ ) :
492 _timep(timep), _selftimep(NULL), _eventp(NULL), _recursion_counters(NULL), _timers(timers), _event_type(type) {
493 initialize();
494 }
495
496 inline void suspend() { _t.stop(); _timers[_event_type].stop(); }
497 inline void resume() { _t.start(); _timers[_event_type].start(); }
498
499 ~PerfClassTraceTime();
500 void initialize();
501 };
502
503 #endif // SHARE_CLASSFILE_CLASSLOADER_HPP