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