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_locked_or_safepoint(Module_lock);
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 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 free_buckets();
195 }
196
197 PackageEntry* PackageEntryTable::new_entry(unsigned int hash, Symbol* name, ModuleEntry* module) {
198 assert(Module_lock->owned_by_self(), "should have the Module_lock");
199 PackageEntry* entry = (PackageEntry*)Hashtable<Symbol*, mtModule>::allocate_new_entry(hash, name);
200
201 JFR_ONLY(INIT_ID(entry);)
202
203 // Initialize fields specific to a PackageEntry
204 entry->init();
205 entry->name()->increment_refcount();
206 entry->set_module(module);
207 return entry;
208 }
209
210 void PackageEntryTable::add_entry(int index, PackageEntry* new_entry) {
211 assert(Module_lock->owned_by_self(), "should have the Module_lock");
212 Hashtable<Symbol*, mtModule>::add_entry(index, (HashtableEntry<Symbol*, mtModule>*)new_entry);
213 }
214
215 // Create package in loader's package entry table and return the entry.
216 // If entry already exists, return null. Assume Module lock was taken by caller.
217 PackageEntry* PackageEntryTable::locked_create_entry_or_null(Symbol* name, ModuleEntry* module) {
218 assert(Module_lock->owned_by_self(), "should have the Module_lock");
219 // Check if package already exists. Return NULL if it does.
220 if (lookup_only(name) != NULL) {
221 return NULL;
222 } else {
223 PackageEntry* entry = new_entry(compute_hash(name), name, module);
224 add_entry(index_for(name), entry);
225 return entry;
226 }
227 }
228
229 PackageEntry* PackageEntryTable::lookup(Symbol* name, ModuleEntry* module) {
230 MutexLocker ml(Module_lock);
231 PackageEntry* p = lookup_only(name);
232 if (p != NULL) {
233 return p;
234 } else {
235 assert(module != NULL, "module should never be null");
236 PackageEntry* entry = new_entry(compute_hash(name), name, module);
237 add_entry(index_for(name), entry);
238 return entry;
239 }
240 }
241
242 PackageEntry* PackageEntryTable::lookup_only(Symbol* name) {
243 MutexLockerEx ml(Module_lock->owned_by_self() ? NULL : Module_lock);
244 int index = index_for(name);
245 for (PackageEntry* p = bucket(index); p != NULL; p = p->next()) {
246 if (p->name()->fast_compare(name) == 0) {
247 return p;
248 }
249 }
250 return NULL;
251 }
252
253 // Called when a define module for java.base is being processed.
254 // Verify the packages loaded thus far are in java.base's package list.
255 void PackageEntryTable::verify_javabase_packages(GrowableArray<Symbol*> *pkg_list) {
256 assert_lock_strong(Module_lock);
257 for (int i = 0; i < table_size(); i++) {
258 for (PackageEntry* entry = bucket(i);
259 entry != NULL;
260 entry = entry->next()) {
261 ModuleEntry* m = entry->module();
262 Symbol* module_name = (m == NULL ? NULL : m->name());
263 if (module_name != NULL &&
264 (module_name->fast_compare(vmSymbols::java_base()) == 0) &&
265 !pkg_list->contains(entry->name())) {
266 ResourceMark rm;
267 vm_exit_during_initialization("A non-" JAVA_BASE_NAME " package was loaded prior to module system initialization", entry->name()->as_C_string());
268 }
269 }
270 }
271
272 }
273
274 // iteration of qualified exports
275 void PackageEntry::package_exports_do(ModuleClosure* f) {
276 assert_locked_or_safepoint(Module_lock);
277 assert(f != NULL, "invariant");
278
279 if (has_qual_exports_list()) {
280 int qe_len = _qualified_exports->length();
281
282 for (int i = 0; i < qe_len; ++i) {
283 f->do_module(_qualified_exports->at(i));
284 }
285 }
286 }
287
288 bool PackageEntry::exported_pending_delete() const {
289 assert_locked_or_safepoint(Module_lock);
290 return (is_unqual_exported() && _qualified_exports != NULL);
291 }
292
293 // Remove dead entries from all packages' exported list
294 void PackageEntryTable::purge_all_package_exports() {
295 assert_locked_or_safepoint(Module_lock);
296 for (int i = 0; i < table_size(); i++) {
297 for (PackageEntry* entry = bucket(i);
298 entry != NULL;
299 entry = entry->next()) {
300 if (entry->exported_pending_delete()) {
301 // exported list is pending deletion due to a transition
302 // from qualified to unqualified
303 entry->delete_qualified_exports();
304 } else if (entry->is_qual_exported()) {
305 entry->purge_qualified_exports();
306 }
307 }
308 }
309 }
310
311 void PackageEntryTable::print(outputStream* st) {
312 st->print_cr("Package Entry Table (table_size=%d, entries=%d)",
313 table_size(), number_of_entries());
314 for (int i = 0; i < table_size(); i++) {
315 for (PackageEntry* probe = bucket(i);
316 probe != NULL;
317 probe = probe->next()) {
318 probe->print(st);
319 }
320 }
321 }
322
323 // This function may be called from debuggers so access private fields directly
324 // to prevent triggering locking-related asserts that could result from calling
325 // getter methods.
326 void PackageEntry::print(outputStream* st) {
327 ResourceMark rm;
328 st->print_cr("package entry " PTR_FORMAT " name %s module %s classpath_index "
329 INT32_FORMAT " is_exported_unqualified %d is_exported_allUnnamed %d " "next " PTR_FORMAT,
330 p2i(this), name()->as_C_string(),
331 (module()->is_named() ? module()->name()->as_C_string() : UNNAMED_MODULE),
332 _classpath_index, _export_flags == PKG_EXP_UNQUALIFIED,
333 _export_flags == PKG_EXP_ALLUNNAMED, p2i(next()));
334 }
335
336 void PackageEntryTable::verify() {
337 verify_table<PackageEntry>("Package Entry Table");
338 }
339
340 void PackageEntry::verify() {
341 guarantee(name() != NULL, "A package entry must have a corresponding symbol name.");
342 }