1 /*
2 * Copyright (c) 2016, 2019, 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, mtModule);
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 assert(Module_lock->owned_by_self(), "should have the 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 assert(!module()->is_open(), "should have been checked already");
113 assert(Module_lock->owned_by_self(), "should have the Module_lock");
114 if (!is_unqual_exported()) {
115 _export_flags = PKG_EXP_ALLUNNAMED;
116 }
117 }
118
119 // Remove dead module entries within the package's exported list. Note that
120 // if all of the modules on the _qualified_exports get purged the list does not
121 // get deleted. This prevents the package from illegally transitioning from
122 // exported to non-exported.
123 void PackageEntry::purge_qualified_exports() {
124 assert_locked_or_safepoint(Module_lock);
125 if (_must_walk_exports &&
126 _qualified_exports != NULL &&
127 !_qualified_exports->is_empty()) {
128
129 // This package's _must_walk_exports flag will be reset based
130 // on the remaining live modules on the exports list.
131 _must_walk_exports = false;
132
133 if (log_is_enabled(Trace, module)) {
134 ResourceMark rm;
135 assert(name() != NULL, "PackageEntry without a valid name");
136 ModuleEntry* pkg_mod = module();
137 log_trace(module)("PackageEntry::purge_qualified_exports(): package %s defined in module %s, exports list being walked",
138 name()->as_C_string(),
139 (pkg_mod == NULL || pkg_mod->name() == NULL) ? UNNAMED_MODULE : pkg_mod->name()->as_C_string());
140 }
141
142 // Go backwards because this removes entries that are dead.
143 int len = _qualified_exports->length();
144 for (int idx = len - 1; idx >= 0; idx--) {
145 ModuleEntry* module_idx = _qualified_exports->at(idx);
146 ClassLoaderData* cld_idx = module_idx->loader_data();
147 if (cld_idx->is_unloading()) {
148 _qualified_exports->delete_at(idx);
149 } else {
150 // Update the need to walk this package's exports based on live modules
151 set_export_walk_required(cld_idx);
152 }
153 }
154 }
155 }
156
157 void PackageEntry::delete_qualified_exports() {
158 if (_qualified_exports != NULL) {
159 delete _qualified_exports;
160 }
161 _qualified_exports = NULL;
162 }
163
164 PackageEntryTable::PackageEntryTable(int table_size)
165 : Hashtable<Symbol*, mtModule>(table_size, sizeof(PackageEntry))
166 {
167 }
168
169 PackageEntryTable::~PackageEntryTable() {
170 // Walk through all buckets and all entries in each bucket,
171 // freeing each entry.
172 for (int i = 0; i < table_size(); ++i) {
173 for (PackageEntry* p = bucket(i); p != NULL;) {
174 PackageEntry* to_remove = p;
175 // read next before freeing.
176 p = p->next();
177
178 // Clean out the C heap allocated qualified exports list first before freeing the entry
179 to_remove->delete_qualified_exports();
180 to_remove->name()->decrement_refcount();
181
182 // Unlink from the Hashtable prior to freeing
183 unlink_entry(to_remove);
184 FREE_C_HEAP_ARRAY(char, to_remove);
185 }
186 }
187 assert(number_of_entries() == 0, "should have removed all entries");
188 assert(new_entry_free_list() == NULL, "entry present on PackageEntryTable's free list");
189 }
190
191 PackageEntry* PackageEntryTable::new_entry(unsigned int hash, Symbol* name, ModuleEntry* module) {
192 assert(Module_lock->owned_by_self(), "should have the Module_lock");
193 PackageEntry* entry = (PackageEntry*)Hashtable<Symbol*, mtModule>::allocate_new_entry(hash, name);
194
195 JFR_ONLY(INIT_ID(entry);)
196
197 // Initialize fields specific to a PackageEntry
198 entry->init();
199 entry->name()->increment_refcount();
200 entry->set_module(module);
201 return entry;
202 }
203
204 void PackageEntryTable::add_entry(int index, PackageEntry* new_entry) {
205 assert(Module_lock->owned_by_self(), "should have the Module_lock");
206 Hashtable<Symbol*, mtModule>::add_entry(index, (HashtableEntry<Symbol*, mtModule>*)new_entry);
207 }
208
209 // Create package entry in loader's package entry table. Assume Module lock
210 // was taken by caller.
211 void PackageEntryTable::locked_create_entry(Symbol* name, ModuleEntry* module) {
212 assert(Module_lock->owned_by_self(), "should have the Module_lock");
213 assert(locked_lookup_only(name) == NULL, "Package entry already exists");
214 PackageEntry* entry = new_entry(compute_hash(name), name, module);
215 add_entry(index_for(name), entry);
216 }
217
218 // Create package entry in loader's package entry table if it does not already
219 // exist. Assume Module lock was taken by caller.
220 void PackageEntryTable::locked_create_entry_if_not_exist(Symbol* name, ModuleEntry* module) {
221 assert(Module_lock->owned_by_self(), "should have the Module_lock");
222 // Check if package entry already exists. If not, create it.
223 if (locked_lookup_only(name) == NULL) {
224 locked_create_entry(name, module);
225 }
226 }
227
228 PackageEntry* PackageEntryTable::lookup(Symbol* name, ModuleEntry* module) {
229 MutexLocker ml(Module_lock);
230 PackageEntry* p = locked_lookup_only(name);
231 if (p != NULL) {
232 return p;
233 } else {
234 assert(module != NULL, "module should never be null");
235 PackageEntry* entry = new_entry(compute_hash(name), name, module);
236 add_entry(index_for(name), entry);
237 return entry;
238 }
239 }
240
241 PackageEntry* PackageEntryTable::lookup_only(Symbol* name) {
242 assert(!Module_lock->owned_by_self(), "should not have the Module_lock - use locked_lookup_only");
243 MutexLocker ml(Module_lock);
244 return locked_lookup_only(name);
245 }
246
247 PackageEntry* PackageEntryTable::locked_lookup_only(Symbol* name) {
248 assert(Module_lock->owned_by_self(), "should have the Module_lock");
249 int index = index_for(name);
250 for (PackageEntry* p = bucket(index); p != NULL; p = p->next()) {
251 if (p->name()->fast_compare(name) == 0) {
252 return p;
253 }
254 }
255 return NULL;
256 }
257
258 // Called when a define module for java.base is being processed.
259 // Verify the packages loaded thus far are in java.base's package list.
260 void PackageEntryTable::verify_javabase_packages(GrowableArray<Symbol*> *pkg_list) {
261 assert_lock_strong(Module_lock);
262 for (int i = 0; i < table_size(); i++) {
263 for (PackageEntry* entry = bucket(i);
264 entry != NULL;
265 entry = entry->next()) {
266 ModuleEntry* m = entry->module();
267 Symbol* module_name = (m == NULL ? NULL : m->name());
268 if (module_name != NULL &&
269 (module_name->fast_compare(vmSymbols::java_base()) == 0) &&
270 !pkg_list->contains(entry->name())) {
271 ResourceMark rm;
272 vm_exit_during_initialization("A non-" JAVA_BASE_NAME " package was loaded prior to module system initialization", entry->name()->as_C_string());
273 }
274 }
275 }
276
277 }
278
279 // iteration of qualified exports
280 void PackageEntry::package_exports_do(ModuleClosure* f) {
281 assert_locked_or_safepoint(Module_lock);
282 assert(f != NULL, "invariant");
283
284 if (has_qual_exports_list()) {
285 int qe_len = _qualified_exports->length();
286
287 for (int i = 0; i < qe_len; ++i) {
288 f->do_module(_qualified_exports->at(i));
289 }
290 }
291 }
292
293 bool PackageEntry::exported_pending_delete() const {
294 assert_locked_or_safepoint(Module_lock);
295 return (is_unqual_exported() && _qualified_exports != NULL);
296 }
297
298 // Remove dead entries from all packages' exported list
299 void PackageEntryTable::purge_all_package_exports() {
300 assert_locked_or_safepoint(Module_lock);
301 for (int i = 0; i < table_size(); i++) {
302 for (PackageEntry* entry = bucket(i);
303 entry != NULL;
304 entry = entry->next()) {
305 if (entry->exported_pending_delete()) {
306 // exported list is pending deletion due to a transition
307 // from qualified to unqualified
308 entry->delete_qualified_exports();
309 } else if (entry->is_qual_exported()) {
310 entry->purge_qualified_exports();
311 }
312 }
313 }
314 }
315
316 void PackageEntryTable::print(outputStream* st) {
317 st->print_cr("Package Entry Table (table_size=%d, entries=%d)",
318 table_size(), number_of_entries());
319 for (int i = 0; i < table_size(); i++) {
320 for (PackageEntry* probe = bucket(i);
321 probe != NULL;
322 probe = probe->next()) {
323 probe->print(st);
324 }
325 }
326 }
327
328 // This function may be called from debuggers so access private fields directly
329 // to prevent triggering locking-related asserts that could result from calling
330 // getter methods.
331 void PackageEntry::print(outputStream* st) {
332 ResourceMark rm;
333 st->print_cr("package entry " PTR_FORMAT " name %s module %s classpath_index "
334 INT32_FORMAT " is_exported_unqualified %d is_exported_allUnnamed %d " "next " PTR_FORMAT,
335 p2i(this), name()->as_C_string(),
336 (module()->is_named() ? module()->name()->as_C_string() : UNNAMED_MODULE),
337 _classpath_index, _export_flags == PKG_EXP_UNQUALIFIED,
338 _export_flags == PKG_EXP_ALLUNNAMED, p2i(next()));
339 }
340
341 void PackageEntryTable::verify() {
342 verify_table<PackageEntry>("Package Entry Table");
343 }
344
345 void PackageEntry::verify() {
346 guarantee(name() != NULL, "A package entry must have a corresponding symbol name.");
347 }