1 /*
2 * Copyright (c) 2016, 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 #include "precompiled.hpp"
26 #include "classfile/moduleEntry.hpp"
27 #include "classfile/packageEntry.hpp"
28 #include "logging/log.hpp"
29 #include "memory/archiveUtils.hpp"
30 #include "memory/metaspaceShared.hpp"
31 #include "memory/resourceArea.hpp"
32 #include "oops/array.hpp"
33 #include "oops/symbol.hpp"
34 #include "runtime/java.hpp"
35 #include "runtime/handles.inline.hpp"
36 #include "utilities/events.hpp"
37 #include "utilities/growableArray.hpp"
38 #include "utilities/hashtable.inline.hpp"
39 #include "utilities/ostream.hpp"
40 #include "utilities/quickSort.hpp"
41 #include "utilities/resourceHash.hpp"
42
43 // Returns true if this package specifies m as a qualified export, including through an unnamed export
44 bool PackageEntry::is_qexported_to(ModuleEntry* m) const {
45 assert(Module_lock->owned_by_self(), "should have the Module_lock");
46 assert(m != NULL, "No module to lookup in this package's qualified exports list");
47 if (is_exported_allUnnamed() && !m->is_named()) {
48 return true;
49 } else if (!has_qual_exports_list()) {
50 return false;
51 } else {
52 return _qualified_exports->contains(m);
53 }
54 }
55
56 // Add a module to the package's qualified export list.
57 void PackageEntry::add_qexport(ModuleEntry* m) {
58 assert(Module_lock->owned_by_self(), "should have the Module_lock");
59 if (!has_qual_exports_list()) {
60 // Lazily create a package's qualified exports list.
61 // Initial size is small, do not anticipate export lists to be large.
62 _qualified_exports = new (ResourceObj::C_HEAP, mtModule) GrowableArray<ModuleEntry*>(QUAL_EXP_SIZE, mtModule);
63 }
64
65 // Determine, based on this newly established export to module m,
66 // if this package's export list should be walked at a GC safepoint.
67 set_export_walk_required(m->loader_data());
68
69 // Establish exportability to module m
70 _qualified_exports->append_if_missing(m);
71 }
72
73 // If the module's loader, that an export is being established to, is
74 // not the same loader as this module's and is not one of the 3 builtin
75 // class loaders, then this package's export list must be walked at GC
76 // safepoint. Modules have the same life cycle as their defining class
77 // loaders and should be removed if dead.
78 void PackageEntry::set_export_walk_required(ClassLoaderData* m_loader_data) {
79 assert_locked_or_safepoint(Module_lock);
80 ModuleEntry* this_pkg_mod = module();
81 if (!_must_walk_exports &&
82 (this_pkg_mod == NULL || this_pkg_mod->loader_data() != m_loader_data) &&
83 !m_loader_data->is_builtin_class_loader_data()) {
84 _must_walk_exports = true;
85 if (log_is_enabled(Trace, module)) {
86 ResourceMark rm;
87 assert(name() != NULL, "PackageEntry without a valid name");
88 log_trace(module)("PackageEntry::set_export_walk_required(): package %s defined in module %s, exports list must be walked",
89 name()->as_C_string(),
90 (this_pkg_mod == NULL || this_pkg_mod->name() == NULL) ?
91 UNNAMED_MODULE : this_pkg_mod->name()->as_C_string());
92 }
93 }
94 }
95
96 // Set the package's exported states based on the value of the ModuleEntry.
97 void PackageEntry::set_exported(ModuleEntry* m) {
98 assert(Module_lock->owned_by_self(), "should have the Module_lock");
99 if (is_unqual_exported()) {
100 // An exception could be thrown, but choose to simply ignore.
101 // Illegal to convert an unqualified exported package to be qualifiedly exported
102 return;
103 }
104
105 if (m == NULL) {
106 // NULL indicates the package is being unqualifiedly exported. Clean up
107 // the qualified list at the next safepoint.
108 set_unqual_exported();
109 } else {
110 // Add the exported module
111 add_qexport(m);
112 }
113 }
114
115 // Set the package as exported to all unnamed modules unless the package is
116 // already unqualifiedly exported.
117 void PackageEntry::set_is_exported_allUnnamed() {
118 assert(!module()->is_open(), "should have been checked already");
119 assert(Module_lock->owned_by_self(), "should have the Module_lock");
120 if (!is_unqual_exported()) {
121 _export_flags = PKG_EXP_ALLUNNAMED;
122 }
123 }
124
125 // Remove dead module entries within the package's exported list. Note that
126 // if all of the modules on the _qualified_exports get purged the list does not
127 // get deleted. This prevents the package from illegally transitioning from
128 // exported to non-exported.
129 void PackageEntry::purge_qualified_exports() {
130 assert_locked_or_safepoint(Module_lock);
131 if (_must_walk_exports &&
132 _qualified_exports != NULL &&
133 !_qualified_exports->is_empty()) {
134
135 // This package's _must_walk_exports flag will be reset based
136 // on the remaining live modules on the exports list.
137 _must_walk_exports = false;
138
139 if (log_is_enabled(Trace, module)) {
140 ResourceMark rm;
141 assert(name() != NULL, "PackageEntry without a valid name");
142 ModuleEntry* pkg_mod = module();
143 log_trace(module)("PackageEntry::purge_qualified_exports(): package %s defined in module %s, exports list being walked",
144 name()->as_C_string(),
145 (pkg_mod == NULL || pkg_mod->name() == NULL) ? UNNAMED_MODULE : pkg_mod->name()->as_C_string());
146 }
147
148 // Go backwards because this removes entries that are dead.
149 int len = _qualified_exports->length();
150 for (int idx = len - 1; idx >= 0; idx--) {
151 ModuleEntry* module_idx = _qualified_exports->at(idx);
152 ClassLoaderData* cld_idx = module_idx->loader_data();
153 if (cld_idx->is_unloading()) {
154 _qualified_exports->delete_at(idx);
155 } else {
156 // Update the need to walk this package's exports based on live modules
157 set_export_walk_required(cld_idx);
158 }
159 }
160 }
161 }
162
163 void PackageEntry::delete_qualified_exports() {
164 if (_qualified_exports != NULL) {
165 delete _qualified_exports;
166 }
167 _qualified_exports = NULL;
168 }
169
170 PackageEntryTable::PackageEntryTable(int table_size)
171 : Hashtable<Symbol*, mtModule>(table_size, sizeof(PackageEntry))
172 {
173 }
174
175 PackageEntryTable::~PackageEntryTable() {
176 // Walk through all buckets and all entries in each bucket,
177 // freeing each entry.
178 for (int i = 0; i < table_size(); ++i) {
179 for (PackageEntry* p = bucket(i); p != NULL;) {
180 PackageEntry* to_remove = p;
181 // read next before freeing.
182 p = p->next();
183
184 // Clean out the C heap allocated qualified exports list first before freeing the entry
185 to_remove->delete_qualified_exports();
186 to_remove->name()->decrement_refcount();
187
188 // Unlink from the Hashtable prior to freeing
189 unlink_entry(to_remove);
190 FREE_C_HEAP_ARRAY(char, to_remove);
191 }
192 }
193 assert(number_of_entries() == 0, "should have removed all entries");
194 assert(new_entry_free_list() == NULL, "entry present on PackageEntryTable's free list");
195 }
196
197 #if INCLUDE_CDS_JAVA_HEAP
198 typedef ResourceHashtable<
199 const PackageEntry*,
200 PackageEntry*,
201 primitive_hash<const PackageEntry*>,
202 primitive_equals<const PackageEntry*>,
203 557, // prime number
204 ResourceObj::C_HEAP> ArchivedPackageEntries;
205 static ArchivedPackageEntries* _archived_packages_entries = NULL;
206
207 PackageEntry* PackageEntry::allocate_archived_entry() const {
208 assert(!in_unnamed_module(), "unnamed packages/modules are not archived");
209 PackageEntry* archived_entry = (PackageEntry*)MetaspaceShared::read_write_space_alloc(sizeof(PackageEntry));
210 memcpy((void*)archived_entry, (void*)this, sizeof(PackageEntry));
211
212 if (_archived_packages_entries == NULL) {
213 _archived_packages_entries = new (ResourceObj::C_HEAP, mtClass)ArchivedPackageEntries();
214 }
215 assert(_archived_packages_entries->get(this) == NULL, "Each PackageEntry must not be shared across PackageEntryTables");
216 _archived_packages_entries->put(this, archived_entry);
217
218 return archived_entry;
219 }
220
221 PackageEntry* PackageEntry::get_archived_entry(PackageEntry* orig_entry) {
222 PackageEntry** ptr = _archived_packages_entries->get(orig_entry);
223 assert(ptr != NULL && *ptr != NULL, "must have been allocated");
224 return *ptr;
225 }
226
227 void PackageEntry::init_as_archived_entry() {
228 Array<ModuleEntry*>* archived_qualified_exports = ModuleEntry::write_archived_entry_array(_qualified_exports);
229
230 set_next(NULL);
231 set_literal(MetaspaceShared::get_relocated_symbol(literal()));
232 set_hash(0x0); // re-init at runtime
233 _module = ModuleEntry::get_archived_entry(_module);
234 _qualified_exports = (GrowableArray<ModuleEntry*>*)archived_qualified_exports;
235 _defined_by_cds_in_class_path = 0;
236
237 ArchivePtrMarker::mark_pointer((address*)literal_addr());
238 ArchivePtrMarker::mark_pointer((address*)&_module);
239 ArchivePtrMarker::mark_pointer((address*)&_qualified_exports);
240 }
241
242 void PackageEntry::load_from_archive() {
243 _qualified_exports = ModuleEntry::read_archived_entry_array((Array<ModuleEntry*>*)_qualified_exports);
244 JFR_ONLY(INIT_ID(this);)
245 }
246
247 static int compare_package_by_name(PackageEntry* a, PackageEntry* b) {
248 return a->name()->fast_compare(b->name());
249 }
250
251 Array<PackageEntry*>* PackageEntryTable::allocate_archived_entries() {
252 // First count the packages in named modules
253 int n, i;
254 for (n = 0, i = 0; i < table_size(); ++i) {
255 for (PackageEntry* p = bucket(i); p != NULL; p = p->next()) {
256 if (p->module()->name() != NULL) {
257 n++;
258 }
259 }
260 }
261
262 Array<PackageEntry*>* archived_packages = MetaspaceShared::new_rw_array<PackageEntry*>(n);
263 for (n = 0, i = 0; i < table_size(); ++i) {
264 for (PackageEntry* p = bucket(i); p != NULL; p = p->next()) {
265 if (p->module()->name() != NULL) {
266 // We don't archive unnamed modules, or packages in unnamed modules. They will be
267 // created on-demand at runtime as classes in such packages are loaded.
268 archived_packages->at_put(n++, p);
269 }
270 }
271 }
272 if (n > 1) {
273 QuickSort::sort(archived_packages->data(), n, (_sort_Fn)compare_package_by_name, true);
274 }
275 for (i = 0; i < n; i++) {
276 archived_packages->at_put(i, archived_packages->at(i)->allocate_archived_entry());
277 ArchivePtrMarker::mark_pointer((address*)archived_packages->adr_at(i));
278 }
279 return archived_packages;
280 }
281
282 void PackageEntryTable::init_archived_entries(Array<PackageEntry*>* archived_packages) {
283 for (int i = 0; i < archived_packages->length(); i++) {
284 PackageEntry* archived_entry = archived_packages->at(i);
285 archived_entry->init_as_archived_entry();
286 }
287 }
288
289 void PackageEntryTable::load_archived_entries(Array<PackageEntry*>* archived_packages) {
290 assert(UseSharedSpaces, "runtime only");
291
292 for (int i = 0; i < archived_packages->length(); i++) {
293 PackageEntry* archived_entry = archived_packages->at(i);
294 archived_entry->load_from_archive();
295
296 unsigned int hash = compute_hash(archived_entry->name());
297 archived_entry->set_hash(hash);
298 add_entry(hash_to_index(hash), archived_entry);
299 }
300 }
301
302 #endif // INCLUDE_CDS_JAVA_HEAP
303
304 PackageEntry* PackageEntryTable::new_entry(unsigned int hash, Symbol* name, ModuleEntry* module) {
305 assert(Module_lock->owned_by_self(), "should have the Module_lock");
306 PackageEntry* entry = (PackageEntry*)Hashtable<Symbol*, mtModule>::allocate_new_entry(hash, name);
307
308 JFR_ONLY(INIT_ID(entry);)
309
310 // Initialize fields specific to a PackageEntry
311 entry->init();
312 entry->name()->increment_refcount();
313 entry->set_module(module);
314 return entry;
315 }
316
317 void PackageEntryTable::add_entry(int index, PackageEntry* new_entry) {
318 assert(Module_lock->owned_by_self(), "should have the Module_lock");
319 Hashtable<Symbol*, mtModule>::add_entry(index, (HashtableEntry<Symbol*, mtModule>*)new_entry);
320 }
321
322 // Create package entry in loader's package entry table. Assume Module lock
323 // was taken by caller.
324 void PackageEntryTable::locked_create_entry(Symbol* name, ModuleEntry* module) {
325 assert(Module_lock->owned_by_self(), "should have the Module_lock");
326 assert(locked_lookup_only(name) == NULL, "Package entry already exists");
327 PackageEntry* entry = new_entry(compute_hash(name), name, module);
328 add_entry(index_for(name), entry);
329 }
330
331 // Create package entry in loader's package entry table if it does not already
332 // exist. Assume Module lock was taken by caller.
333 void PackageEntryTable::locked_create_entry_if_not_exist(Symbol* name, ModuleEntry* module) {
334 assert(Module_lock->owned_by_self(), "should have the Module_lock");
335 // Check if package entry already exists. If not, create it.
336 if (locked_lookup_only(name) == NULL) {
337 locked_create_entry(name, module);
338 }
339 }
340
341 PackageEntry* PackageEntryTable::lookup(Symbol* name, ModuleEntry* module) {
342 MutexLocker ml(Module_lock);
343 PackageEntry* p = locked_lookup_only(name);
344 if (p != NULL) {
345 return p;
346 } else {
347 assert(module != NULL, "module should never be null");
348 PackageEntry* entry = new_entry(compute_hash(name), name, module);
349 add_entry(index_for(name), entry);
350 return entry;
351 }
352 }
353
354 PackageEntry* PackageEntryTable::lookup_only(Symbol* name) {
355 assert(!Module_lock->owned_by_self(), "should not have the Module_lock - use locked_lookup_only");
356 MutexLocker ml(Module_lock);
357 return locked_lookup_only(name);
358 }
359
360 PackageEntry* PackageEntryTable::locked_lookup_only(Symbol* name) {
361 assert(Module_lock->owned_by_self(), "should have the Module_lock");
362 int index = index_for(name);
363 for (PackageEntry* p = bucket(index); p != NULL; p = p->next()) {
364 if (p->name()->fast_compare(name) == 0) {
365 return p;
366 }
367 }
368 return NULL;
369 }
370
371 // Called when a define module for java.base is being processed.
372 // Verify the packages loaded thus far are in java.base's package list.
373 void PackageEntryTable::verify_javabase_packages(GrowableArray<Symbol*> *pkg_list) {
374 assert_lock_strong(Module_lock);
375 for (int i = 0; i < table_size(); i++) {
376 for (PackageEntry* entry = bucket(i);
377 entry != NULL;
378 entry = entry->next()) {
379 ModuleEntry* m = entry->module();
380 Symbol* module_name = (m == NULL ? NULL : m->name());
381 if (module_name != NULL &&
382 (module_name->fast_compare(vmSymbols::java_base()) == 0) &&
383 !pkg_list->contains(entry->name())) {
384 ResourceMark rm;
385 vm_exit_during_initialization("A non-" JAVA_BASE_NAME " package was loaded prior to module system initialization", entry->name()->as_C_string());
386 }
387 }
388 }
389 }
390
391 // iteration of qualified exports
392 void PackageEntry::package_exports_do(ModuleClosure* f) {
393 assert_locked_or_safepoint(Module_lock);
394 assert(f != NULL, "invariant");
395
396 if (has_qual_exports_list()) {
397 int qe_len = _qualified_exports->length();
398
399 for (int i = 0; i < qe_len; ++i) {
400 f->do_module(_qualified_exports->at(i));
401 }
402 }
403 }
404
405 bool PackageEntry::exported_pending_delete() const {
406 assert_locked_or_safepoint(Module_lock);
407 return (is_unqual_exported() && _qualified_exports != NULL);
408 }
409
410 // Remove dead entries from all packages' exported list
411 void PackageEntryTable::purge_all_package_exports() {
412 assert_locked_or_safepoint(Module_lock);
413 for (int i = 0; i < table_size(); i++) {
414 for (PackageEntry* entry = bucket(i);
415 entry != NULL;
416 entry = entry->next()) {
417 if (entry->exported_pending_delete()) {
418 // exported list is pending deletion due to a transition
419 // from qualified to unqualified
420 entry->delete_qualified_exports();
421 } else if (entry->is_qual_exported()) {
422 entry->purge_qualified_exports();
423 }
424 }
425 }
426 }
427
428 void PackageEntryTable::print(outputStream* st) {
429 st->print_cr("Package Entry Table (table_size=%d, entries=%d)",
430 table_size(), number_of_entries());
431 for (int i = 0; i < table_size(); i++) {
432 for (PackageEntry* probe = bucket(i);
433 probe != NULL;
434 probe = probe->next()) {
435 probe->print(st);
436 }
437 }
438 }
439
440 // This function may be called from debuggers so access private fields directly
441 // to prevent triggering locking-related asserts that could result from calling
442 // getter methods.
443 void PackageEntry::print(outputStream* st) {
444 ResourceMark rm;
445 st->print_cr("package entry " PTR_FORMAT " name %s module %s classpath_index "
446 INT32_FORMAT " is_exported_unqualified %d is_exported_allUnnamed %d " "next " PTR_FORMAT,
447 p2i(this), name()->as_C_string(),
448 (module()->is_named() ? module()->name()->as_C_string() : UNNAMED_MODULE),
449 _classpath_index, _export_flags == PKG_EXP_UNQUALIFIED,
450 _export_flags == PKG_EXP_ALLUNNAMED, p2i(next()));
451 }
452
453 void PackageEntryTable::verify() {
454 verify_table<PackageEntry>("Package Entry Table");
455 }
456
457 void PackageEntry::verify() {
458 guarantee(name() != NULL, "A package entry must have a corresponding symbol name.");
459 }