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comparison src/share/vm/classfile/loaderConstraints.cpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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children 38836cf1d8d2 0c3f888b7636
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-1:000000000000 0:a61af66fc99e
1 /*
2 * Copyright 2003-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 # include "incls/_precompiled.incl"
26 # include "incls/_loaderConstraints.cpp.incl"
27
28 LoaderConstraintTable::LoaderConstraintTable(int nof_buckets)
29 : Hashtable(nof_buckets, sizeof(LoaderConstraintEntry)) {};
30
31
32 LoaderConstraintEntry* LoaderConstraintTable::new_entry(
33 unsigned int hash, symbolOop name,
34 klassOop klass, int num_loaders,
35 int max_loaders) {
36 LoaderConstraintEntry* entry;
37 entry = (LoaderConstraintEntry*)Hashtable::new_entry(hash, klass);
38 entry->set_name(name);
39 entry->set_num_loaders(num_loaders);
40 entry->set_max_loaders(max_loaders);
41 return entry;
42 }
43
44
45 void LoaderConstraintTable::oops_do(OopClosure* f) {
46 for (int index = 0; index < table_size(); index++) {
47 for (LoaderConstraintEntry* probe = bucket(index);
48 probe != NULL;
49 probe = probe->next()) {
50 f->do_oop((oop*)(probe->name_addr()));
51 if (probe->klass() != NULL) {
52 f->do_oop((oop*)probe->klass_addr());
53 }
54 for (int n = 0; n < probe->num_loaders(); n++) {
55 if (probe->loader(n) != NULL) {
56 f->do_oop(probe->loader_addr(n));
57 }
58 }
59 }
60 }
61 }
62
63 // We must keep the symbolOop used in the name alive. We'll use the
64 // loaders to decide if a particular entry can be purged.
65 void LoaderConstraintTable::always_strong_classes_do(OopClosure* blk) {
66 // We must keep the symbolOop used in the name alive.
67 for (int cindex = 0; cindex < table_size(); cindex++) {
68 for (LoaderConstraintEntry* lc_probe = bucket(cindex);
69 lc_probe != NULL;
70 lc_probe = lc_probe->next()) {
71 assert (lc_probe->name() != NULL, "corrupted loader constraint table");
72 blk->do_oop((oop*)lc_probe->name_addr());
73 }
74 }
75 }
76
77
78 // The loaderConstraintTable must always be accessed with the
79 // SystemDictionary lock held. This is true even for readers as
80 // entries in the table could be being dynamically resized.
81
82 LoaderConstraintEntry** LoaderConstraintTable::find_loader_constraint(
83 symbolHandle name, Handle loader) {
84
85 unsigned int hash = compute_hash(name);
86 int index = hash_to_index(hash);
87 LoaderConstraintEntry** pp = bucket_addr(index);
88 while (*pp) {
89 LoaderConstraintEntry* p = *pp;
90 if (p->hash() == hash) {
91 if (p->name() == name()) {
92 for (int i = p->num_loaders() - 1; i >= 0; i--) {
93 if (p->loader(i) == loader()) {
94 return pp;
95 }
96 }
97 }
98 }
99 pp = p->next_addr();
100 }
101 return pp;
102 }
103
104
105 void LoaderConstraintTable::purge_loader_constraints(BoolObjectClosure* is_alive) {
106 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint")
107 // Remove unloaded entries from constraint table
108 for (int index = 0; index < table_size(); index++) {
109 LoaderConstraintEntry** p = bucket_addr(index);
110 while(*p) {
111 LoaderConstraintEntry* probe = *p;
112 klassOop klass = probe->klass();
113 // Remove klass that is no longer alive
114 if (klass != NULL && !is_alive->do_object_b(klass)) {
115 probe->set_klass(NULL);
116 if (TraceLoaderConstraints) {
117 ResourceMark rm;
118 tty->print_cr("[Purging class object from constraint for name %s,"
119 " loader list:",
120 probe->name()->as_C_string());
121 for (int i = 0; i < probe->num_loaders(); i++) {
122 tty->print_cr("[ [%d]: %s", i,
123 SystemDictionary::loader_name(probe->loader(i)));
124 }
125 }
126 }
127 // Remove entries no longer alive from loader array
128 int n = 0;
129 while (n < probe->num_loaders()) {
130 if (probe->loader(n) != NULL) {
131 if (!is_alive->do_object_b(probe->loader(n))) {
132 if (TraceLoaderConstraints) {
133 ResourceMark rm;
134 tty->print_cr("[Purging loader %s from constraint for name %s",
135 SystemDictionary::loader_name(probe->loader(n)),
136 probe->name()->as_C_string()
137 );
138 }
139
140 // Compact array
141 int num = probe->num_loaders() - 1;
142 probe->set_num_loaders(num);
143 probe->set_loader(n, probe->loader(num));
144 probe->set_loader(num, NULL);
145
146 if (TraceLoaderConstraints) {
147 ResourceMark rm;
148 tty->print_cr("[New loader list:");
149 for (int i = 0; i < probe->num_loaders(); i++) {
150 tty->print_cr("[ [%d]: %s", i,
151 SystemDictionary::loader_name(probe->loader(i)));
152 }
153 }
154
155 continue; // current element replaced, so restart without
156 // incrementing n
157 }
158 }
159 n++;
160 }
161 // Check whether entry should be purged
162 if (probe->num_loaders() < 2) {
163 if (TraceLoaderConstraints) {
164 ResourceMark rm;
165 tty->print("[Purging complete constraint for name %s\n",
166 probe->name()->as_C_string());
167 }
168
169 // Purge entry
170 *p = probe->next();
171 FREE_C_HEAP_ARRAY(oop, probe->loaders());
172 free_entry(probe);
173 } else {
174 #ifdef ASSERT
175 assert(is_alive->do_object_b(probe->name()), "name should be live");
176 if (probe->klass() != NULL) {
177 assert(is_alive->do_object_b(probe->klass()), "klass should be live");
178 }
179 for (n = 0; n < probe->num_loaders(); n++) {
180 if (probe->loader(n) != NULL) {
181 assert(is_alive->do_object_b(probe->loader(n)), "loader should be live");
182 }
183 }
184 #endif
185 // Go to next entry
186 p = probe->next_addr();
187 }
188 }
189 }
190 }
191
192 bool LoaderConstraintTable::add_entry(symbolHandle class_name,
193 klassOop klass1, Handle class_loader1,
194 klassOop klass2, Handle class_loader2) {
195 int failure_code = 0; // encode different reasons for failing
196
197 if (klass1 != NULL && klass2 != NULL && klass1 != klass2) {
198 failure_code = 1;
199 } else {
200 klassOop klass = klass1 != NULL ? klass1 : klass2;
201
202 LoaderConstraintEntry** pp1 = find_loader_constraint(class_name,
203 class_loader1);
204 if (*pp1 != NULL && (*pp1)->klass() != NULL) {
205 if (klass != NULL) {
206 if (klass != (*pp1)->klass()) {
207 failure_code = 2;
208 }
209 } else {
210 klass = (*pp1)->klass();
211 }
212 }
213
214 LoaderConstraintEntry** pp2 = find_loader_constraint(class_name,
215 class_loader2);
216 if (*pp2 != NULL && (*pp2)->klass() != NULL) {
217 if (klass != NULL) {
218 if (klass != (*pp2)->klass()) {
219 failure_code = 3;
220 }
221 } else {
222 klass = (*pp2)->klass();
223 }
224 }
225
226 if (failure_code == 0) {
227 if (*pp1 == NULL && *pp2 == NULL) {
228 unsigned int hash = compute_hash(class_name);
229 int index = hash_to_index(hash);
230 LoaderConstraintEntry* p;
231 p = new_entry(hash, class_name(), klass, 2, 2);
232 p->set_loaders(NEW_C_HEAP_ARRAY(oop, 2));
233 p->set_loader(0, class_loader1());
234 p->set_loader(1, class_loader2());
235 p->set_klass(klass);
236 p->set_next(bucket(index));
237 set_entry(index, p);
238 if (TraceLoaderConstraints) {
239 ResourceMark rm;
240 tty->print("[Adding new constraint for name: %s, loader[0]: %s,"
241 " loader[1]: %s ]\n",
242 class_name()->as_C_string(),
243 SystemDictionary::loader_name(class_loader1()),
244 SystemDictionary::loader_name(class_loader2())
245 );
246 }
247 } else if (*pp1 == *pp2) {
248 /* constraint already imposed */
249 if ((*pp1)->klass() == NULL) {
250 (*pp1)->set_klass(klass);
251 if (TraceLoaderConstraints) {
252 ResourceMark rm;
253 tty->print("[Setting class object in existing constraint for"
254 " name: %s and loader %s ]\n",
255 class_name()->as_C_string(),
256 SystemDictionary::loader_name(class_loader1())
257 );
258 }
259 } else {
260 assert((*pp1)->klass() == klass, "loader constraints corrupted");
261 }
262 } else if (*pp1 == NULL) {
263 extend_loader_constraint(*pp2, class_loader1, klass);
264 } else if (*pp2 == NULL) {
265 extend_loader_constraint(*pp1, class_loader2, klass);
266 } else {
267 merge_loader_constraints(pp1, pp2, klass);
268 }
269 }
270 }
271
272 if (failure_code != 0 && TraceLoaderConstraints) {
273 ResourceMark rm;
274 const char* reason = "";
275 switch(failure_code) {
276 case 1: reason = "the class objects presented by loader[0] and loader[1]"
277 " are different"; break;
278 case 2: reason = "the class object presented by loader[0] does not match"
279 " the stored class object in the constraint"; break;
280 case 3: reason = "the class object presented by loader[1] does not match"
281 " the stored class object in the constraint"; break;
282 default: reason = "unknown reason code";
283 }
284 tty->print("[Failed to add constraint for name: %s, loader[0]: %s,"
285 " loader[1]: %s, Reason: %s ]\n",
286 class_name()->as_C_string(),
287 SystemDictionary::loader_name(class_loader1()),
288 SystemDictionary::loader_name(class_loader2()),
289 reason
290 );
291 }
292
293 return failure_code == 0;
294 }
295
296
297 // return true if the constraint was updated, false if the constraint is
298 // violated
299 bool LoaderConstraintTable::check_or_update(instanceKlassHandle k,
300 Handle loader,
301 symbolHandle name) {
302 LoaderConstraintEntry* p = *(find_loader_constraint(name, loader));
303 if (p && p->klass() != NULL && p->klass() != k()) {
304 if (TraceLoaderConstraints) {
305 ResourceMark rm;
306 tty->print("[Constraint check failed for name %s, loader %s: "
307 "the presented class object differs from that stored ]\n",
308 name()->as_C_string(),
309 SystemDictionary::loader_name(loader()));
310 }
311 return false;
312 } else {
313 if (p && p->klass() == NULL) {
314 p->set_klass(k());
315 if (TraceLoaderConstraints) {
316 ResourceMark rm;
317 tty->print("[Updating constraint for name %s, loader %s, "
318 "by setting class object ]\n",
319 name()->as_C_string(),
320 SystemDictionary::loader_name(loader()));
321 }
322 }
323 return true;
324 }
325 }
326
327 klassOop LoaderConstraintTable::find_constrained_klass(symbolHandle name,
328 Handle loader) {
329 LoaderConstraintEntry *p = *(find_loader_constraint(name, loader));
330 if (p != NULL && p->klass() != NULL)
331 return p->klass();
332
333 // No constraints, or else no klass loaded yet.
334 return NULL;
335 }
336
337
338 klassOop LoaderConstraintTable::find_constrained_elem_klass(symbolHandle name,
339 symbolHandle elem_name,
340 Handle loader,
341 TRAPS) {
342 LoaderConstraintEntry *p = *(find_loader_constraint(name, loader));
343 if (p != NULL) {
344 assert(p->klass() == NULL, "Expecting null array klass");
345
346 // The array name has a constraint, but it will not have a class. Check
347 // each loader for an associated elem
348 for (int i = 0; i < p->num_loaders(); i++) {
349 Handle no_protection_domain;
350
351 klassOop k = SystemDictionary::find(elem_name, p->loader(i), no_protection_domain, THREAD);
352 if (k != NULL) {
353 // Return the first elem klass found.
354 return k;
355 }
356 }
357 }
358
359 // No constraints, or else no klass loaded yet.
360 return NULL;
361 }
362
363
364 void LoaderConstraintTable::ensure_loader_constraint_capacity(
365 LoaderConstraintEntry *p,
366 int nfree) {
367 if (p->max_loaders() - p->num_loaders() < nfree) {
368 int n = nfree + p->num_loaders();
369 oop* new_loaders = NEW_C_HEAP_ARRAY(oop, n);
370 memcpy(new_loaders, p->loaders(), sizeof(oop) * p->num_loaders());
371 p->set_max_loaders(n);
372 FREE_C_HEAP_ARRAY(oop, p->loaders());
373 p->set_loaders(new_loaders);
374 }
375 }
376
377
378 void LoaderConstraintTable::extend_loader_constraint(LoaderConstraintEntry* p,
379 Handle loader,
380 klassOop klass) {
381 ensure_loader_constraint_capacity(p, 1);
382 int num = p->num_loaders();
383 p->set_loader(num, loader());
384 p->set_num_loaders(num + 1);
385 if (TraceLoaderConstraints) {
386 ResourceMark rm;
387 tty->print("[Extending constraint for name %s by adding loader[%d]: %s %s",
388 p->name()->as_C_string(),
389 num,
390 SystemDictionary::loader_name(loader()),
391 (p->klass() == NULL ? " and setting class object ]\n" : " ]\n")
392 );
393 }
394 if (p->klass() == NULL) {
395 p->set_klass(klass);
396 } else {
397 assert(klass == NULL || p->klass() == klass, "constraints corrupted");
398 }
399 }
400
401
402 void LoaderConstraintTable::merge_loader_constraints(
403 LoaderConstraintEntry** pp1,
404 LoaderConstraintEntry** pp2,
405 klassOop klass) {
406 // make sure *pp1 has higher capacity
407 if ((*pp1)->max_loaders() < (*pp2)->max_loaders()) {
408 LoaderConstraintEntry** tmp = pp2;
409 pp2 = pp1;
410 pp1 = tmp;
411 }
412
413 LoaderConstraintEntry* p1 = *pp1;
414 LoaderConstraintEntry* p2 = *pp2;
415
416 ensure_loader_constraint_capacity(p1, p2->num_loaders());
417
418 for (int i = 0; i < p2->num_loaders(); i++) {
419 int num = p1->num_loaders();
420 p1->set_loader(num, p2->loader(i));
421 p1->set_num_loaders(num + 1);
422 }
423
424 if (TraceLoaderConstraints) {
425 ResourceMark rm;
426 tty->print_cr("[Merged constraints for name %s, new loader list:",
427 p1->name()->as_C_string()
428 );
429
430 for (int i = 0; i < p1->num_loaders(); i++) {
431 tty->print_cr("[ [%d]: %s", i,
432 SystemDictionary::loader_name(p1->loader(i)));
433 }
434 if (p1->klass() == NULL) {
435 tty->print_cr("[... and setting class object]");
436 }
437 }
438
439 // p1->klass() will hold NULL if klass, p2->klass(), and old
440 // p1->klass() are all NULL. In addition, all three must have
441 // matching non-NULL values, otherwise either the constraints would
442 // have been violated, or the constraints had been corrupted (and an
443 // assertion would fail).
444 if (p2->klass() != NULL) {
445 assert(p2->klass() == klass, "constraints corrupted");
446 }
447 if (p1->klass() == NULL) {
448 p1->set_klass(klass);
449 } else {
450 assert(p1->klass() == klass, "constraints corrupted");
451 }
452
453 *pp2 = p2->next();
454 FREE_C_HEAP_ARRAY(oop, p2->loaders());
455 free_entry(p2);
456 return;
457 }
458
459
460 void LoaderConstraintTable::verify(Dictionary* dictionary) {
461 Thread *thread = Thread::current();
462 for (int cindex = 0; cindex < _loader_constraint_size; cindex++) {
463 for (LoaderConstraintEntry* probe = bucket(cindex);
464 probe != NULL;
465 probe = probe->next()) {
466 guarantee(probe->name()->is_symbol(), "should be symbol");
467 if (probe->klass() != NULL) {
468 instanceKlass* ik = instanceKlass::cast(probe->klass());
469 guarantee(ik->name() == probe->name(), "name should match");
470 symbolHandle name (thread, ik->name());
471 Handle loader(thread, ik->class_loader());
472 unsigned int d_hash = dictionary->compute_hash(name, loader);
473 int d_index = dictionary->hash_to_index(d_hash);
474 klassOop k = dictionary->find_class(d_index, d_hash, name, loader);
475 guarantee(k == probe->klass(), "klass should be in dictionary");
476 }
477 for (int n = 0; n< probe->num_loaders(); n++) {
478 guarantee(probe->loader(n)->is_oop_or_null(), "should be oop");
479 }
480 }
481 }
482 }
483
484 #ifndef PRODUCT
485
486 // Called with the system dictionary lock held
487 void LoaderConstraintTable::print() {
488 ResourceMark rm;
489
490 assert_locked_or_safepoint(SystemDictionary_lock);
491 tty->print_cr("Java loader constraints (entries=%d)", _loader_constraint_size);
492 for (int cindex = 0; cindex < _loader_constraint_size; cindex++) {
493 for (LoaderConstraintEntry* probe = bucket(cindex);
494 probe != NULL;
495 probe = probe->next()) {
496 tty->print("%4d: ", cindex);
497 probe->name()->print();
498 tty->print(" , loaders:");
499 for (int n = 0; n < probe->num_loaders(); n++) {
500 probe->loader(n)->print_value();
501 tty->print(", ");
502 }
503 tty->cr();
504 }
505 }
506 }
507 #endif