1 /*
2 * Copyright (c) 1997, 2024, 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/perfDataTypes.hpp"
31 #include "utilities/exceptions.hpp"
32 #include "utilities/macros.hpp"
33 #include "utilities/zipLibrary.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
58 virtual bool is_modules_image() const { return false; }
59 virtual bool is_jar_file() const { return false; }
60 // Is this entry created from the "Class-path" attribute from a JAR Manifest?
61 virtual bool from_class_path_attr() const { return false; }
62 virtual const char* name() const = 0;
63 virtual JImageFile* jimage() const { return nullptr; }
64 virtual void close_jimage() {}
65 // Constructor
66 ClassPathEntry() : _next(nullptr) {}
67 // Attempt to locate file_name through this class path entry.
68 // Returns a class file parsing stream if successful.
69 virtual ClassFileStream* open_stream(JavaThread* current, const char* name) = 0;
70 // Open the stream for a specific class loader
71 virtual ClassFileStream* open_stream_for_loader(JavaThread* current, const char* name, ClassLoaderData* loader_data) {
72 return open_stream(current, name);
73 }
74 };
75
76 class ClassPathDirEntry: public ClassPathEntry {
77 private:
78 const char* _dir; // Name of directory
79 public:
80 const char* name() const { return _dir; }
81 ClassPathDirEntry(const char* dir) {
82 _dir = copy_path(dir);
83 }
84 virtual ~ClassPathDirEntry();
85 ClassFileStream* open_stream(JavaThread* current, const char* name);
86 };
87
88 class ClassPathZipEntry: public ClassPathEntry {
89 private:
90 jzfile* _zip; // The zip archive
91 const char* _zip_name; // Name of zip archive
92 bool _from_class_path_attr; // From the "Class-path" attribute of a jar file
93 public:
94 bool is_jar_file() const { return true; }
95 bool from_class_path_attr() const { return _from_class_path_attr; }
96 const char* name() const { return _zip_name; }
97 ClassPathZipEntry(jzfile* zip, const char* zip_name, bool is_boot_append, bool from_class_path_attr);
98 virtual ~ClassPathZipEntry();
99 u1* open_entry(JavaThread* current, const char* name, jint* filesize, bool nul_terminate);
100 ClassFileStream* open_stream(JavaThread* current, const char* name);
101 };
102
103
104 // For java image files
105 class ClassPathImageEntry: public ClassPathEntry {
106 private:
107 const char* _name;
108 DEBUG_ONLY(static ClassPathImageEntry* _singleton;)
109 public:
110 bool is_modules_image() const;
111 const char* name() const { return _name == nullptr ? "" : _name; }
112 JImageFile* jimage() const;
113 JImageFile* jimage_non_null() const;
114 void close_jimage();
115 ClassPathImageEntry(JImageFile* jimage, const char* name);
116 virtual ~ClassPathImageEntry() { ShouldNotReachHere(); }
117 ClassFileStream* open_stream(JavaThread* current, const char* name);
118 ClassFileStream* open_stream_for_loader(JavaThread* current, const char* name, ClassLoaderData* loader_data);
119 };
120
121 // ModuleClassPathList contains a linked list of ClassPathEntry's
122 // that have been specified for a specific module. Currently,
123 // the only way to specify a module/path pair is via the --patch-module
124 // command line option.
125 class ModuleClassPathList : public CHeapObj<mtClass> {
126 private:
127 Symbol* _module_name;
128 // First and last entries of class path entries for a specific module
129 ClassPathEntry* _module_first_entry;
130 ClassPathEntry* _module_last_entry;
131 public:
132 Symbol* module_name() const { return _module_name; }
133 ClassPathEntry* module_first_entry() const { return _module_first_entry; }
134 ModuleClassPathList(Symbol* module_name);
135 ~ModuleClassPathList();
136 void add_to_list(ClassPathEntry* new_entry);
137 };
138
139 class ClassLoader: AllStatic {
140 public:
141 enum ClassLoaderType {
142 BOOT_LOADER = 1, /* boot loader */
143 PLATFORM_LOADER = 2, /* PlatformClassLoader */
144 APP_LOADER = 3 /* AppClassLoader */
145 };
146 protected:
147
148 // Performance counters
149 static PerfCounter* _perf_accumulated_time;
150 static PerfCounter* _perf_classes_inited;
151 static PerfCounter* _perf_class_init_time;
152 static PerfCounter* _perf_class_init_selftime;
153 static PerfCounter* _perf_classes_verified;
154 static PerfCounter* _perf_class_verify_time;
155 static PerfCounter* _perf_class_verify_selftime;
156 static PerfCounter* _perf_classes_linked;
157 static PerfCounter* _perf_class_link_time;
158 static PerfCounter* _perf_class_link_selftime;
159 static PerfCounter* _perf_shared_classload_time;
160 static PerfCounter* _perf_sys_classload_time;
161 static PerfCounter* _perf_app_classload_time;
162 static PerfCounter* _perf_app_classload_selftime;
163 static PerfCounter* _perf_app_classload_count;
164 static PerfCounter* _perf_define_appclasses;
165 static PerfCounter* _perf_define_appclass_time;
166 static PerfCounter* _perf_define_appclass_selftime;
167 static PerfCounter* _perf_app_classfile_bytes_read;
168 static PerfCounter* _perf_sys_classfile_bytes_read;
169
170 static PerfCounter* _unsafe_defineClassCallCounter;
171
172 // Count the time taken to hash the scondary superclass arrays.
173 static PerfCounter* _perf_secondary_hash_time;
174
175 // The boot class path consists of 3 ordered pieces:
176 // 1. the module/path pairs specified to --patch-module
177 // --patch-module=<module>=<file>(<pathsep><file>)*
178 // 2. the base piece
179 // [jimage | build with exploded modules]
180 // 3. boot loader append path
181 // [-Xbootclasspath/a]; [jvmti appended entries]
182 //
183 // The boot loader must obey this order when attempting
184 // to load a class.
185
186 // 1. Contains the module/path pairs specified to --patch-module
187 static GrowableArray<ModuleClassPathList*>* _patch_mod_entries;
188
189 // 2. the base piece
190 // Contains the ClassPathEntry of the modular java runtime image.
191 // If no java runtime image is present, this indicates a
192 // build with exploded modules is being used instead.
193 static ClassPathEntry* _jrt_entry;
194 static GrowableArray<ModuleClassPathList*>* _exploded_entries;
195 enum { EXPLODED_ENTRY_SIZE = 80 }; // Initial number of exploded modules
196
197 // 3. the boot loader's append path
198 // [-Xbootclasspath/a]; [jvmti appended entries]
199 // Note: boot loader append path does not support named modules.
200 static ClassPathEntry* volatile _first_append_entry_list;
201 static ClassPathEntry* first_append_entry() {
202 return Atomic::load_acquire(&_first_append_entry_list);
203 }
204
205 // Last entry in linked list of appended ClassPathEntry instances
206 static ClassPathEntry* volatile _last_append_entry;
207
208 // Info used by CDS
209 CDS_ONLY(static ClassPathEntry* _app_classpath_entries;)
210 CDS_ONLY(static ClassPathEntry* _last_app_classpath_entry;)
211 CDS_ONLY(static ClassPathEntry* _module_path_entries;)
212 CDS_ONLY(static ClassPathEntry* _last_module_path_entry;)
213 CDS_ONLY(static void setup_app_search_path(JavaThread* current, const char* class_path);)
214 CDS_ONLY(static void setup_module_search_path(JavaThread* current, const char* path);)
215 static bool add_to_app_classpath_entries(JavaThread* current,
216 ClassPathEntry* entry,
217 bool check_for_duplicates);
218 CDS_ONLY(static void add_to_module_path_entries(const char* path,
219 ClassPathEntry* entry);)
220
221 public:
222 CDS_ONLY(static ClassPathEntry* app_classpath_entries() {return _app_classpath_entries;})
223 CDS_ONLY(static ClassPathEntry* module_path_entries() {return _module_path_entries;})
224
225 static bool has_bootclasspath_append() { return first_append_entry() != nullptr; }
226
227 protected:
228 // Initialization:
229 // - setup the boot loader's system class path
230 // - setup the boot loader's patch mod entries, if present
231 // - create the ModuleEntry for java.base
232 static void setup_bootstrap_search_path(JavaThread* current);
233 static void setup_bootstrap_search_path_impl(JavaThread* current, const char *class_path);
234 static void setup_patch_mod_entries();
235 static void create_javabase();
236
237 static void* dll_lookup(void* lib, const char* name, const char* path);
238 static void load_java_library();
239 static void load_jimage_library();
240
241 public:
242 static void* zip_library_handle();
243 static jzfile* open_zip_file(const char* canonical_path, char** error_msg, JavaThread* thread);
244 static ClassPathEntry* create_class_path_entry(JavaThread* current,
245 const char *path, const struct stat* st,
246 bool is_boot_append,
247 bool from_class_path_attr);
248
249 // Canonicalizes path names, so strcmp will work properly. This is mainly
250 // to avoid confusing the zip library
251 static char* get_canonical_path(const char* orig, Thread* thread);
252 static const char* file_name_for_class_name(const char* class_name,
253 int class_name_len);
254 static PackageEntry* get_package_entry(Symbol* pkg_name, ClassLoaderData* loader_data);
255 static int crc32(int crc, const char* buf, int len);
256 static bool update_class_path_entry_list(JavaThread* current,
257 const char *path,
258 bool check_for_duplicates,
259 bool is_boot_append,
260 bool from_class_path_attr);
261 static void print_bootclasspath();
262
263 // Timing
264 static PerfCounter* perf_accumulated_time() { return _perf_accumulated_time; }
265 static PerfCounter* perf_classes_inited() { return _perf_classes_inited; }
266 static PerfCounter* perf_class_init_time() { return _perf_class_init_time; }
267 static PerfCounter* perf_class_init_selftime() { return _perf_class_init_selftime; }
268 static PerfCounter* perf_classes_verified() { return _perf_classes_verified; }
269 static PerfCounter* perf_class_verify_time() { return _perf_class_verify_time; }
270 static PerfCounter* perf_class_verify_selftime() { return _perf_class_verify_selftime; }
271 static PerfCounter* perf_classes_linked() { return _perf_classes_linked; }
272 static PerfCounter* perf_class_link_time() { return _perf_class_link_time; }
273 static PerfCounter* perf_class_link_selftime() { return _perf_class_link_selftime; }
274 static PerfCounter* perf_shared_classload_time() { return _perf_shared_classload_time; }
275 static PerfCounter* perf_secondary_hash_time() {
276 return _perf_secondary_hash_time;
277 }
278 static PerfCounter* perf_sys_classload_time() { return _perf_sys_classload_time; }
279 static PerfCounter* perf_app_classload_time() { return _perf_app_classload_time; }
280 static PerfCounter* perf_app_classload_selftime() { return _perf_app_classload_selftime; }
281 static PerfCounter* perf_app_classload_count() { return _perf_app_classload_count; }
282 static PerfCounter* perf_define_appclasses() { return _perf_define_appclasses; }
283 static PerfCounter* perf_define_appclass_time() { return _perf_define_appclass_time; }
284 static PerfCounter* perf_define_appclass_selftime() { return _perf_define_appclass_selftime; }
285 static PerfCounter* perf_app_classfile_bytes_read() { return _perf_app_classfile_bytes_read; }
286 static PerfCounter* perf_sys_classfile_bytes_read() { return _perf_sys_classfile_bytes_read; }
287
288 // Record how many calls to Unsafe_DefineClass
289 static PerfCounter* unsafe_defineClassCallCounter() {
290 return _unsafe_defineClassCallCounter;
291 }
292
293 // Modular java runtime image is present vs. a build with exploded modules
294 static bool has_jrt_entry() { return (_jrt_entry != nullptr); }
295 static ClassPathEntry* get_jrt_entry() { return _jrt_entry; }
296 static void close_jrt_image();
297
298 // Add a module's exploded directory to the boot loader's exploded module build list
299 static void add_to_exploded_build_list(JavaThread* current, Symbol* module_name);
300
301 // Search the module list for the class file stream based on the file name and java package
302 static ClassFileStream* search_module_entries(JavaThread* current,
303 const GrowableArray<ModuleClassPathList*>* const module_list,
304 PackageEntry* pkg_entry, // Java package entry derived from the class name
305 const char* const file_name);
306
307 // Load individual .class file
308 static InstanceKlass* load_class(Symbol* class_name, PackageEntry* pkg_entry, bool search_append_only, TRAPS);
309
310 // If the specified package has been loaded by the system, then returns
311 // the name of the directory or ZIP file that the package was loaded from.
312 // Returns null if the package was not loaded.
313 // Note: The specified name can either be the name of a class or package.
314 // If a package name is specified, then it must be "/"-separator and also
315 // end with a trailing "/".
316 static oop get_system_package(const char* name, TRAPS);
317
318 // Returns an array of Java strings representing all of the currently
319 // loaded system packages.
320 // Note: The package names returned are "/"-separated and end with a
321 // trailing "/".
322 static objArrayOop get_system_packages(TRAPS);
323
324 // Initialization
325 static void initialize(TRAPS);
326 static void classLoader_init2(JavaThread* current);
327 CDS_ONLY(static void initialize_shared_path(JavaThread* current);)
328 CDS_ONLY(static void initialize_module_path(TRAPS);)
329
330 static int compute_Object_vtable();
331
332 static ClassPathEntry* classpath_entry(int n);
333
334 static bool is_in_patch_mod_entries(Symbol* module_name);
335
336 #if INCLUDE_CDS
337 // Sharing dump and restore
338
339 // Helper function used by CDS code to get the number of boot classpath
340 // entries during shared classpath setup time.
341 static int num_boot_classpath_entries();
342
343 static ClassPathEntry* get_next_boot_classpath_entry(ClassPathEntry* e);
344
345 // Helper function used by CDS code to get the number of app classpath
346 // entries during shared classpath setup time.
347 static int num_app_classpath_entries();
348
349 // Helper function used by CDS code to get the number of module path
350 // entries during shared classpath setup time.
351 static int num_module_path_entries();
352 static void exit_with_path_failure(const char* error, const char* message);
353 static char* skip_uri_protocol(char* source);
354 static void record_result(JavaThread* current, InstanceKlass* ik,
355 const ClassFileStream* stream, bool redefined);
356 #endif
357
358 static char* lookup_vm_options();
359
360 // Determines if the named module is present in the
361 // modules jimage file or in the exploded modules directory.
362 static bool is_module_observable(const char* module_name);
363
364 static JImageLocationRef jimage_find_resource(JImageFile* jf, const char* module_name,
365 const char* file_name, jlong &size);
366
367 static void trace_class_path(const char* msg, const char* name = nullptr);
368
369 // VM monitoring and management support
370 static jlong classloader_time_ms();
371 static jlong class_method_total_size();
372 static jlong class_init_count();
373 static jlong class_init_time_ms();
374 static jlong class_verify_time_ms();
375 static jlong class_link_count();
376 static jlong class_link_time_ms();
377
378 // adds a class path to the boot append entries
379 static void add_to_boot_append_entries(ClassPathEntry* new_entry);
380
381 // creates a class path zip entry (returns null if JAR file cannot be opened)
382 static ClassPathZipEntry* create_class_path_zip_entry(const char *apath, bool is_boot_append);
383
384 static bool string_ends_with(const char* str, const char* str_to_find);
385
386 // Extract package name from a fully qualified class name
387 // *bad_class_name is set to true if there's a problem with parsing class_name, to
388 // distinguish from a class_name with no package name, as both cases have a null return value
389 static Symbol* package_from_class_name(const Symbol* class_name, bool* bad_class_name = nullptr);
390
391 // Debugging
392 static void verify() PRODUCT_RETURN;
393 };
394
395 // PerfClassTraceTime is used to measure time for class loading related events.
396 // This class tracks cumulative time and exclusive time for specific event types.
397 // During the execution of one event, other event types (e.g. class loading and
398 // resolution) as well as recursive calls of the same event type could happen.
399 // Only one elapsed timer (cumulative) and one thread-local self timer (exclusive)
400 // (i.e. only one event type) are active at a time even multiple PerfClassTraceTime
401 // instances have been created as multiple events are happening.
402 class PerfClassTraceTime {
403 public:
404 enum {
405 CLASS_LOAD = 0,
406 CLASS_LINK = 1,
407 CLASS_VERIFY = 2,
408 CLASS_CLINIT = 3,
409 DEFINE_CLASS = 4,
410 EVENT_TYPE_COUNT = 5
411 };
412 protected:
413 // _t tracks time from initialization to destruction of this timer instance
414 // including time for all other event types, and recursive calls of this type.
415 // When a timer is called recursively, the elapsedTimer _t would not be used.
416 elapsedTimer _t;
417 PerfLongCounter* _timep;
418 PerfLongCounter* _selftimep;
419 PerfLongCounter* _eventp;
420 // pointer to thread-local recursion counter and timer array
421 // The thread_local timers track cumulative time for specific event types
422 // exclusive of time for other event types, but including recursive calls
423 // of the same type.
424 int* _recursion_counters;
425 elapsedTimer* _timers;
426 int _event_type;
427 int _prev_active_event;
428
429 public:
430
431 inline PerfClassTraceTime(PerfLongCounter* timep, /* counter incremented with inclusive time */
432 PerfLongCounter* selftimep, /* counter incremented with exclusive time */
433 PerfLongCounter* eventp, /* event counter */
434 int* recursion_counters, /* thread-local recursion counter array */
435 elapsedTimer* timers, /* thread-local timer array */
436 int type /* event type */ ) :
437 _timep(timep), _selftimep(selftimep), _eventp(eventp), _recursion_counters(recursion_counters), _timers(timers), _event_type(type) {
438 initialize();
439 }
440
441 inline PerfClassTraceTime(PerfLongCounter* timep, /* counter incremented with inclusive time */
442 elapsedTimer* timers, /* thread-local timer array */
443 int type /* event type */ ) :
444 _timep(timep), _selftimep(nullptr), _eventp(nullptr), _recursion_counters(nullptr), _timers(timers), _event_type(type) {
445 initialize();
446 }
447
448 ~PerfClassTraceTime();
449 void initialize();
450 };
451
452 #endif // SHARE_CLASSFILE_CLASSLOADER_HPP