1 /*
2 * Copyright (c) 2016, 2018, 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 "utilities/events.hpp"
33 #include "utilities/growableArray.hpp"
34 #include "utilities/hashtable.inline.hpp"
35 #include "utilities/ostream.hpp"
36
37 // Returns true if this package specifies m as a qualified export, including through an unnamed export
38 bool PackageEntry::is_qexported_to(ModuleEntry* m) const {
39 assert(Module_lock->owned_by_self(), "should have the Module_lock");
40 assert(m != NULL, "No module to lookup in this package's qualified exports list");
41 if (is_exported_allUnnamed() && !m->is_named()) {
42 return true;
43 } else if (!has_qual_exports_list()) {
44 return false;
45 } else {
46 return _qualified_exports->contains(m);
47 }
48 }
49
50 // Add a module to the package's qualified export list.
51 void PackageEntry::add_qexport(ModuleEntry* m) {
52 assert(Module_lock->owned_by_self(), "should have the Module_lock");
53 if (!has_qual_exports_list()) {
54 // Lazily create a package's qualified exports list.
55 // Initial size is small, do not anticipate export lists to be large.
56 _qualified_exports = new (ResourceObj::C_HEAP, mtModule) GrowableArray<ModuleEntry*>(QUAL_EXP_SIZE, true);
57 }
58
59 // Determine, based on this newly established export to module m,
60 // if this package's export list should be walked at a GC safepoint.
61 set_export_walk_required(m->loader_data());
62
63 // Establish exportability to module m
64 _qualified_exports->append_if_missing(m);
65 }
66
67 // If the module's loader, that an export is being established to, is
68 // not the same loader as this module's and is not one of the 3 builtin
69 // class loaders, then this package's export list must be walked at GC
70 // safepoint. Modules have the same life cycle as their defining class
71 // loaders and should be removed if dead.
72 void PackageEntry::set_export_walk_required(ClassLoaderData* m_loader_data) {
73 assert_locked_or_safepoint(Module_lock);
74 ModuleEntry* this_pkg_mod = module();
75 if (!_must_walk_exports &&
76 (this_pkg_mod == NULL || this_pkg_mod->loader_data() != m_loader_data) &&
77 !m_loader_data->is_builtin_class_loader_data()) {
78 _must_walk_exports = true;
79 if (log_is_enabled(Trace, module)) {
80 ResourceMark rm;
81 assert(name() != NULL, "PackageEntry without a valid name");
82 log_trace(module)("PackageEntry::set_export_walk_required(): package %s defined in module %s, exports list must be walked",
83 name()->as_C_string(),
84 (this_pkg_mod == NULL || this_pkg_mod->name() == NULL) ?
85 UNNAMED_MODULE : this_pkg_mod->name()->as_C_string());
86 }
87 }
88 }
89
90 // Set the package's exported states based on the value of the ModuleEntry.
91 void PackageEntry::set_exported(ModuleEntry* m) {
92 MutexLocker m1(Module_lock);
93 if (is_unqual_exported()) {
94 // An exception could be thrown, but choose to simply ignore.
95 // Illegal to convert an unqualified exported package to be qualifiedly exported
96 return;
97 }
98
99 if (m == NULL) {
100 // NULL indicates the package is being unqualifiedly exported. Clean up
101 // the qualified list at the next safepoint.
102 set_unqual_exported();
103 } else {
104 // Add the exported module
105 add_qexport(m);
106 }
107 }
108
109 // Set the package as exported to all unnamed modules unless the package is
110 // already unqualifiedly exported.
111 void PackageEntry::set_is_exported_allUnnamed() {
112 if (module()->is_open()) {
113 // No-op for open modules since all packages are unqualifiedly exported
114 return;
115 }
116
117 MutexLocker m1(Module_lock);
118 if (!is_unqual_exported()) {
119 _export_flags = PKG_EXP_ALLUNNAMED;
120 }
121 }
122
123 // Remove dead module entries within the package's exported list. Note that
124 // if all of the modules on the _qualified_exports get purged the list does not
125 // get deleted. This prevents the package from illegally transitioning from
126 // exported to non-exported.
127 void PackageEntry::purge_qualified_exports() {
128 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
129 if (_must_walk_exports &&
130 _qualified_exports != NULL &&
131 !_qualified_exports->is_empty()) {
132 ModuleEntry* pkg_module = module();
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 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
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 free_buckets();
196 }
197
198 PackageEntry* PackageEntryTable::new_entry(unsigned int hash, Symbol* name, ModuleEntry* module) {
199 assert(Module_lock->owned_by_self(), "should have the Module_lock");
200 PackageEntry* entry = (PackageEntry*)Hashtable<Symbol*, mtModule>::allocate_new_entry(hash, name);
201
202 JFR_ONLY(INIT_ID(entry);)
203
204 // Initialize fields specific to a PackageEntry
205 entry->init();
206 entry->name()->increment_refcount();
207 entry->set_module(module);
208 return entry;
209 }
210
211 void PackageEntryTable::add_entry(int index, PackageEntry* new_entry) {
212 assert(Module_lock->owned_by_self(), "should have the Module_lock");
213 Hashtable<Symbol*, mtModule>::add_entry(index, (HashtableEntry<Symbol*, mtModule>*)new_entry);
214 }
215
216 // Create package in loader's package entry table and return the entry.
217 // If entry already exists, return null. Assume Module lock was taken by caller.
218 PackageEntry* PackageEntryTable::locked_create_entry_or_null(Symbol* name, ModuleEntry* module) {
219 assert(Module_lock->owned_by_self(), "should have the Module_lock");
220 // Check if package already exists. Return NULL if it does.
221 if (lookup_only(name) != NULL) {
222 return NULL;
223 } else {
224 PackageEntry* entry = new_entry(compute_hash(name), name, module);
225 add_entry(index_for(name), entry);
226 return entry;
227 }
228 }
229
230 PackageEntry* PackageEntryTable::lookup(Symbol* name, ModuleEntry* module) {
231 PackageEntry* p = lookup_only(name);
232 if (p != NULL) {
233 return p;
234 } else {
235 // If not found, add to table. Grab the PackageEntryTable lock first.
236 MutexLocker ml(Module_lock);
237
238 // Since look-up was done lock-free, we need to check if another thread beat
239 // us in the race to insert the package.
240 PackageEntry* test = lookup_only(name);
241 if (test != NULL) {
242 // A race occurred and another thread introduced the package.
243 return test;
244 } else {
245 assert(module != NULL, "module should never be null");
246 PackageEntry* entry = new_entry(compute_hash(name), name, module);
247 add_entry(index_for(name), entry);
248 return entry;
249 }
250 }
251 }
252
253 PackageEntry* PackageEntryTable::lookup_only(Symbol* name) {
254 int index = index_for(name);
255 for (PackageEntry* p = bucket(index); p != NULL; p = p->next()) {
256 if (p->name()->fast_compare(name) == 0) {
257 return p;
258 }
259 }
260 return NULL;
261 }
262
263 // Called when a define module for java.base is being processed.
264 // Verify the packages loaded thus far are in java.base's package list.
265 void PackageEntryTable::verify_javabase_packages(GrowableArray<Symbol*> *pkg_list) {
266 assert_lock_strong(Module_lock);
267 for (int i = 0; i < table_size(); i++) {
268 for (PackageEntry* entry = bucket(i);
269 entry != NULL;
270 entry = entry->next()) {
271 ModuleEntry* m = entry->module();
272 Symbol* module_name = (m == NULL ? NULL : m->name());
273 if (module_name != NULL &&
274 (module_name->fast_compare(vmSymbols::java_base()) == 0) &&
275 !pkg_list->contains(entry->name())) {
276 ResourceMark rm;
277 vm_exit_during_initialization("A non-" JAVA_BASE_NAME " package was loaded prior to module system initialization", entry->name()->as_C_string());
278 }
279 }
280 }
281
282 }
283
284 // iteration of qualified exports
285 void PackageEntry::package_exports_do(ModuleClosure* f) {
286 assert_locked_or_safepoint(Module_lock);
287 assert(f != NULL, "invariant");
288
289 if (has_qual_exports_list()) {
290 int qe_len = _qualified_exports->length();
291
292 for (int i = 0; i < qe_len; ++i) {
293 f->do_module(_qualified_exports->at(i));
294 }
295 }
296 }
297
298 bool PackageEntry::exported_pending_delete() const {
299 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
300 return (is_unqual_exported() && _qualified_exports != NULL);
301 }
302
303 // Remove dead entries from all packages' exported list
304 void PackageEntryTable::purge_all_package_exports() {
305 assert_locked_or_safepoint(Module_lock);
306 for (int i = 0; i < table_size(); i++) {
307 for (PackageEntry* entry = bucket(i);
308 entry != NULL;
309 entry = entry->next()) {
310 if (entry->exported_pending_delete()) {
311 // exported list is pending deletion due to a transition
312 // from qualified to unqualified
313 entry->delete_qualified_exports();
314 } else if (entry->is_qual_exported()) {
315 entry->purge_qualified_exports();
316 }
317 }
318 }
319 }
320
321 void PackageEntryTable::print(outputStream* st) {
322 st->print_cr("Package Entry Table (table_size=%d, entries=%d)",
323 table_size(), number_of_entries());
324 for (int i = 0; i < table_size(); i++) {
325 for (PackageEntry* probe = bucket(i);
326 probe != NULL;
327 probe = probe->next()) {
328 probe->print(st);
329 }
330 }
331 }
332
333 // This function may be called from debuggers so access private fields directly
334 // to prevent triggering locking-related asserts that could result from calling
335 // getter methods.
336 void PackageEntry::print(outputStream* st) {
337 ResourceMark rm;
338 st->print_cr("package entry " PTR_FORMAT " name %s module %s classpath_index "
339 INT32_FORMAT " is_exported_unqualified %d is_exported_allUnnamed %d " "next " PTR_FORMAT,
340 p2i(this), name()->as_C_string(),
341 (module()->is_named() ? module()->name()->as_C_string() : UNNAMED_MODULE),
342 _classpath_index, _export_flags == PKG_EXP_UNQUALIFIED,
343 _export_flags == PKG_EXP_ALLUNNAMED, p2i(next()));
344 }
345
346 void PackageEntryTable::verify() {
347 verify_table<PackageEntry>("Package Entry Table");
348 }
349
350 void PackageEntry::verify() {
351 guarantee(name() != NULL, "A package entry must have a corresponding symbol name.");
352 }