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