1 /*
2 * Copyright (c) 2016, 2017, 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/resourceArea.hpp"
30 #include "oops/symbol.hpp"
31 #include "runtime/handles.inline.hpp"
32 #include "trace/traceMacros.hpp"
33 #include "utilities/events.hpp"
34 #include "utilities/growableArray.hpp"
35 #include "utilities/hashtable.inline.hpp"
36 #include "utilities/ostream.hpp"
37
38 // Returns true if this package specifies m as a qualified export, including through an unnamed export
39 bool PackageEntry::is_qexported_to(ModuleEntry* m) const {
40 assert(Module_lock->owned_by_self(), "should have the Module_lock");
41 assert(m != NULL, "No module to lookup in this package's qualified exports list");
42 if (is_exported_allUnnamed() && !m->is_named()) {
43 return true;
44 } else if (!has_qual_exports_list()) {
45 return false;
46 } else {
47 return _qualified_exports->contains(m);
48 }
49 }
50
51 // Add a module to the package's qualified export list.
52 void PackageEntry::add_qexport(ModuleEntry* m) {
53 assert(Module_lock->owned_by_self(), "should have the Module_lock");
54 if (!has_qual_exports_list()) {
55 // Lazily create a package's qualified exports list.
56 // Initial size is small, do not anticipate export lists to be large.
57 _qualified_exports = new (ResourceObj::C_HEAP, mtModule) GrowableArray<ModuleEntry*>(QUAL_EXP_SIZE, true);
58 }
59
60 // Determine, based on this newly established export to module m,
61 // if this package's export list should be walked at a GC safepoint.
62 set_export_walk_required(m->loader_data());
63
64 // Establish exportability to module m
65 _qualified_exports->append_if_missing(m);
66 }
67
68 // If the module's loader, that an export is being established to, is
69 // not the same loader as this module's and is not one of the 3 builtin
70 // class loaders, then this package's export list must be walked at GC
71 // safepoint. Modules have the same life cycle as their defining class
72 // loaders and should be removed if dead.
73 void PackageEntry::set_export_walk_required(ClassLoaderData* m_loader_data) {
74 assert_locked_or_safepoint(Module_lock);
75 ModuleEntry* this_pkg_mod = module();
76 if (!_must_walk_exports &&
77 (this_pkg_mod == NULL || this_pkg_mod->loader_data() != m_loader_data) &&
78 !m_loader_data->is_builtin_class_loader_data()) {
79 _must_walk_exports = true;
80 if (log_is_enabled(Trace, module)) {
81 ResourceMark rm;
82 assert(name() != NULL, "PackageEntry without a valid name");
83 log_trace(module)("PackageEntry::set_export_walk_required(): package %s defined in module %s, exports list must be walked",
84 name()->as_C_string(),
85 (this_pkg_mod == NULL || this_pkg_mod->name() == NULL) ?
86 UNNAMED_MODULE : this_pkg_mod->name()->as_C_string());
87 }
88 }
89 }
90
91 // Set the package's exported states based on the value of the ModuleEntry.
92 void PackageEntry::set_exported(ModuleEntry* m) {
93 MutexLocker m1(Module_lock);
94 if (is_unqual_exported()) {
95 // An exception could be thrown, but choose to simply ignore.
96 // Illegal to convert an unqualified exported package to be qualifiedly exported
97 return;
98 }
99
100 if (m == NULL) {
101 // NULL indicates the package is being unqualifiedly exported. Clean up
102 // the qualified list at the next safepoint.
103 set_unqual_exported();
104 } else {
105 // Add the exported module
106 add_qexport(m);
107 }
108 }
109
110 // Set the package as exported to all unnamed modules unless the package is
111 // already unqualifiedly exported.
112 void PackageEntry::set_is_exported_allUnnamed() {
113 if (module()->is_open()) {
114 // No-op for open modules since all packages are unqualifiedly exported
115 return;
116 }
117
118 MutexLocker m1(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(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
130 if (_must_walk_exports &&
131 _qualified_exports != NULL &&
132 !_qualified_exports->is_empty()) {
133 ModuleEntry* pkg_module = module();
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 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
165 if (_qualified_exports != NULL) {
166 delete _qualified_exports;
167 }
168 _qualified_exports = NULL;
169 }
170
171 PackageEntryTable::PackageEntryTable(int table_size)
172 : Hashtable<Symbol*, mtModule>(table_size, sizeof(PackageEntry))
173 {
174 }
175
176 PackageEntryTable::~PackageEntryTable() {
177 // Walk through all buckets and all entries in each bucket,
178 // freeing each entry.
179 for (int i = 0; i < table_size(); ++i) {
180 for (PackageEntry* p = bucket(i); p != NULL;) {
181 PackageEntry* to_remove = p;
182 // read next before freeing.
183 p = p->next();
184
185 // Clean out the C heap allocated qualified exports list first before freeing the entry
186 to_remove->delete_qualified_exports();
187 to_remove->name()->decrement_refcount();
188
189 // Unlink from the Hashtable prior to freeing
190 unlink_entry(to_remove);
191 FREE_C_HEAP_ARRAY(char, to_remove);
192 }
193 }
194 assert(number_of_entries() == 0, "should have removed all entries");
195 assert(new_entry_free_list() == NULL, "entry present on PackageEntryTable's free list");
196 free_buckets();
197 }
198
199 PackageEntry* PackageEntryTable::new_entry(unsigned int hash, Symbol* name, ModuleEntry* module) {
200 assert(Module_lock->owned_by_self(), "should have the Module_lock");
201 PackageEntry* entry = (PackageEntry*) NEW_C_HEAP_ARRAY(char, entry_size(), mtModule);
202
203 // Initialize everything BasicHashtable would
204 entry->set_next(NULL);
205 entry->set_hash(hash);
206 entry->set_literal(name);
207
208 TRACE_INIT_ID(entry);
209
210 // Initialize fields specific to a PackageEntry
211 entry->init();
212 entry->name()->increment_refcount();
213 entry->set_module(module);
214 return entry;
215 }
216
217 void PackageEntryTable::add_entry(int index, PackageEntry* new_entry) {
218 assert(Module_lock->owned_by_self(), "should have the Module_lock");
219 Hashtable<Symbol*, mtModule>::add_entry(index, (HashtableEntry<Symbol*, mtModule>*)new_entry);
220 }
221
222 // Create package in loader's package entry table and return the entry.
223 // If entry already exists, return null. Assume Module lock was taken by caller.
224 PackageEntry* PackageEntryTable::locked_create_entry_or_null(Symbol* name, ModuleEntry* module) {
225 assert(Module_lock->owned_by_self(), "should have the Module_lock");
226 // Check if package already exists. Return NULL if it does.
227 if (lookup_only(name) != NULL) {
228 return NULL;
229 } else {
230 PackageEntry* entry = new_entry(compute_hash(name), name, module);
231 add_entry(index_for(name), entry);
232 return entry;
233 }
234 }
235
236 PackageEntry* PackageEntryTable::lookup(Symbol* name, ModuleEntry* module) {
237 PackageEntry* p = lookup_only(name);
238 if (p != NULL) {
239 return p;
240 } else {
241 // If not found, add to table. Grab the PackageEntryTable lock first.
242 MutexLocker ml(Module_lock);
243
244 // Since look-up was done lock-free, we need to check if another thread beat
245 // us in the race to insert the package.
246 PackageEntry* test = lookup_only(name);
247 if (test != NULL) {
248 // A race occurred and another thread introduced the package.
249 return test;
250 } else {
251 assert(module != NULL, "module should never be null");
252 PackageEntry* entry = new_entry(compute_hash(name), name, module);
253 add_entry(index_for(name), entry);
254 return entry;
255 }
256 }
257 }
258
259 PackageEntry* PackageEntryTable::lookup_only(Symbol* name) {
260 int index = index_for(name);
261 for (PackageEntry* p = bucket(index); p != NULL; p = p->next()) {
262 if (p->name()->fast_compare(name) == 0) {
263 return p;
264 }
265 }
266 return NULL;
267 }
268
269 // Called when a define module for java.base is being processed.
270 // Verify the packages loaded thus far are in java.base's package list.
271 void PackageEntryTable::verify_javabase_packages(GrowableArray<Symbol*> *pkg_list) {
272 assert_lock_strong(Module_lock);
273 for (int i = 0; i < table_size(); i++) {
274 for (PackageEntry* entry = bucket(i);
275 entry != NULL;
276 entry = entry->next()) {
277 ModuleEntry* m = entry->module();
278 Symbol* module_name = (m == NULL ? NULL : m->name());
279 if (module_name != NULL &&
280 (module_name->fast_compare(vmSymbols::java_base()) == 0) &&
281 !pkg_list->contains(entry->name())) {
282 ResourceMark rm;
283 vm_exit_during_initialization("A non-" JAVA_BASE_NAME " package was loaded prior to module system initialization", entry->name()->as_C_string());
284 }
285 }
286 }
287
288 }
289
290 // iteration of qualified exports
291 void PackageEntry::package_exports_do(ModuleClosure* const f) {
292 assert_locked_or_safepoint(Module_lock);
293 assert(f != NULL, "invariant");
294
295 if (has_qual_exports_list()) {
296 int qe_len = _qualified_exports->length();
297
298 for (int i = 0; i < qe_len; ++i) {
299 f->do_module(_qualified_exports->at(i));
300 }
301 }
302 }
303
304 bool PackageEntry::exported_pending_delete() const {
305 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
306 return (is_unqual_exported() && _qualified_exports != NULL);
307 }
308
309 // Remove dead entries from all packages' exported list
310 void PackageEntryTable::purge_all_package_exports() {
311 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
312 for (int i = 0; i < table_size(); i++) {
313 for (PackageEntry* entry = bucket(i);
314 entry != NULL;
315 entry = entry->next()) {
316 if (entry->exported_pending_delete()) {
317 // exported list is pending deletion due to a transition
318 // from qualified to unqualified
319 entry->delete_qualified_exports();
320 } else if (entry->is_qual_exported()) {
321 entry->purge_qualified_exports();
322 }
323 }
324 }
325 }
326
327 void PackageEntryTable::print(outputStream* st) {
328 st->print_cr("Package Entry Table (table_size=%d, entries=%d)",
329 table_size(), number_of_entries());
330 for (int i = 0; i < table_size(); i++) {
331 for (PackageEntry* probe = bucket(i);
332 probe != NULL;
333 probe = probe->next()) {
334 probe->print(st);
335 }
336 }
337 }
338
339 // This function may be called from debuggers so access private fields directly
340 // to prevent triggering locking-related asserts that could result from calling
341 // getter methods.
342 void PackageEntry::print(outputStream* st) {
343 ResourceMark rm;
344 st->print_cr("package entry " PTR_FORMAT " name %s module %s classpath_index "
345 INT32_FORMAT " is_exported_unqualified %d is_exported_allUnnamed %d " "next " PTR_FORMAT,
346 p2i(this), name()->as_C_string(),
347 (module()->is_named() ? module()->name()->as_C_string() : UNNAMED_MODULE),
348 _classpath_index, _export_flags == PKG_EXP_UNQUALIFIED,
349 _export_flags == PKG_EXP_ALLUNNAMED, p2i(next()));
350 }
351
352 void PackageEntryTable::verify() {
353 verify_table<PackageEntry>("Package Entry Table");
354 }
355
356 void PackageEntry::verify() {
357 guarantee(name() != NULL, "A package entry must have a corresponding symbol name.");
358 }