1 /*
2 * Copyright (c) 2005, 2014, 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/javaClasses.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "gc_implementation/shared/vmGCOperations.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "oops/oop.inline.hpp"
31 #include "prims/jvmtiExport.hpp"
32 #include "runtime/arguments.hpp"
33 #include "runtime/globals.hpp"
34 #include "runtime/java.hpp"
35 #include "runtime/javaCalls.hpp"
36 #include "runtime/os.hpp"
37 #include "services/attachListener.hpp"
38 #include "services/diagnosticCommand.hpp"
39 #include "services/heapDumper.hpp"
40
41 volatile bool AttachListener::_initialized;
42
43 // Implementation of "properties" command.
44 //
45 // Invokes sun.misc.VMSupport.serializePropertiesToByteArray to serialize
46 // the system properties into a byte array.
47
48 static Klass* load_and_initialize_klass(Symbol* sh, TRAPS) {
49 Klass* k = SystemDictionary::resolve_or_fail(sh, true, CHECK_NULL);
50 instanceKlassHandle ik (THREAD, k);
51 if (ik->should_be_initialized()) {
52 ik->initialize(CHECK_NULL);
53 }
54 return ik();
55 }
56
57 static jint get_properties(AttachOperation* op, outputStream* out, Symbol* serializePropertiesMethod) {
58 Thread* THREAD = Thread::current();
59 HandleMark hm;
60
61 // load sun.misc.VMSupport
62 Symbol* klass = vmSymbols::sun_misc_VMSupport();
63 Klass* k = load_and_initialize_klass(klass, THREAD);
64 if (HAS_PENDING_EXCEPTION) {
65 java_lang_Throwable::print(PENDING_EXCEPTION, out);
66 CLEAR_PENDING_EXCEPTION;
67 return JNI_ERR;
68 }
69 instanceKlassHandle ik(THREAD, k);
70
71 // invoke the serializePropertiesToByteArray method
72 JavaValue result(T_OBJECT);
73 JavaCallArguments args;
74
75
76 Symbol* signature = vmSymbols::serializePropertiesToByteArray_signature();
77 JavaCalls::call_static(&result,
78 ik,
79 serializePropertiesMethod,
80 signature,
81 &args,
82 THREAD);
83 if (HAS_PENDING_EXCEPTION) {
84 java_lang_Throwable::print(PENDING_EXCEPTION, out);
85 CLEAR_PENDING_EXCEPTION;
86 return JNI_ERR;
87 }
88
89 // The result should be a [B
90 oop res = (oop)result.get_jobject();
91 assert(res->is_typeArray(), "just checking");
92 assert(TypeArrayKlass::cast(res->klass())->element_type() == T_BYTE, "just checking");
93
94 // copy the bytes to the output stream
95 typeArrayOop ba = typeArrayOop(res);
96 jbyte* addr = typeArrayOop(res)->byte_at_addr(0);
97 out->print_raw((const char*)addr, ba->length());
98
99 return JNI_OK;
100 }
101
102 // Implementation of "properties" command.
103 // See also: PrintSystemPropertiesDCmd class
104 static jint get_system_properties(AttachOperation* op, outputStream* out) {
105 return get_properties(op, out, vmSymbols::serializePropertiesToByteArray_name());
106 }
107
108 // Implementation of "agent_properties" command.
109 static jint get_agent_properties(AttachOperation* op, outputStream* out) {
110 return get_properties(op, out, vmSymbols::serializeAgentPropertiesToByteArray_name());
111 }
112
113 // Implementation of "datadump" command.
114 //
115 // Raises a SIGBREAK signal so that VM dump threads, does deadlock detection,
116 // etc. In theory this command should only post a DataDumpRequest to any
117 // JVMTI environment that has enabled this event. However it's useful to
118 // trigger the SIGBREAK handler.
119
120 static jint data_dump(AttachOperation* op, outputStream* out) {
121 if (!ReduceSignalUsage) {
122 AttachListener::pd_data_dump();
123 } else {
124 if (JvmtiExport::should_post_data_dump()) {
125 JvmtiExport::post_data_dump();
126 }
127 }
128 return JNI_OK;
129 }
130
131 // Implementation of "threaddump" command - essentially a remote ctrl-break
132 // See also: ThreadDumpDCmd class
133 //
134 static jint thread_dump(AttachOperation* op, outputStream* out) {
135 bool print_concurrent_locks = false;
136 if (op->arg(0) != NULL && strcmp(op->arg(0), "-l") == 0) {
137 print_concurrent_locks = true;
138 }
139
140 // thread stacks
141 VM_PrintThreads op1(out, print_concurrent_locks);
142 VMThread::execute(&op1);
143
144 // JNI global handles
145 VM_PrintJNI op2(out);
146 VMThread::execute(&op2);
147
148 // Deadlock detection
149 VM_FindDeadlocks op3(out);
150 VMThread::execute(&op3);
151
152 return JNI_OK;
153 }
154
155 // A jcmd attach operation request was received, which will now
156 // dispatch to the diagnostic commands used for serviceability functions.
157 static jint jcmd(AttachOperation* op, outputStream* out) {
158 Thread* THREAD = Thread::current();
159 // All the supplied jcmd arguments are stored as a single
160 // string (op->arg(0)). This is parsed by the Dcmd framework.
161 DCmd::parse_and_execute(DCmd_Source_AttachAPI, out, op->arg(0), ' ', THREAD);
162 if (HAS_PENDING_EXCEPTION) {
163 java_lang_Throwable::print(PENDING_EXCEPTION, out);
164 out->cr();
165 CLEAR_PENDING_EXCEPTION;
166 return JNI_ERR;
167 }
168 return JNI_OK;
169 }
170
171 // Implementation of "dumpheap" command.
172 // See also: HeapDumpDCmd class
173 //
174 // Input arguments :-
175 // arg0: Name of the dump file
176 // arg1: "-live" or "-all"
177 jint dump_heap(AttachOperation* op, outputStream* out) {
178 const char* path = op->arg(0);
179 if (path == NULL || path[0] == '\0') {
180 out->print_cr("No dump file specified");
181 } else {
182 bool live_objects_only = true; // default is true to retain the behavior before this change is made
183 const char* arg1 = op->arg(1);
184 if (arg1 != NULL && (strlen(arg1) > 0)) {
185 if (strcmp(arg1, "-all") != 0 && strcmp(arg1, "-live") != 0) {
186 out->print_cr("Invalid argument to dumpheap operation: %s", arg1);
187 return JNI_ERR;
188 }
189 live_objects_only = strcmp(arg1, "-live") == 0;
190 }
191
192 // Request a full GC before heap dump if live_objects_only = true
193 // This helps reduces the amount of unreachable objects in the dump
194 // and makes it easier to browse.
195 HeapDumper dumper(live_objects_only /* request GC */);
196 int res = dumper.dump(op->arg(0));
197 if (res == 0) {
198 out->print_cr("Heap dump file created");
199 } else {
200 // heap dump failed
201 ResourceMark rm;
202 char* error = dumper.error_as_C_string();
203 if (error == NULL) {
204 out->print_cr("Dump failed - reason unknown");
205 } else {
206 out->print_cr("%s", error);
207 }
208 }
209 }
210 return JNI_OK;
211 }
212
213 // Implementation of "inspectheap" command
214 // See also: ClassHistogramDCmd class
215 //
216 // Input arguments :-
217 // arg0: "-live" or "-all"
218 static jint heap_inspection(AttachOperation* op, outputStream* out) {
219 bool live_objects_only = true; // default is true to retain the behavior before this change is made
220 const char* arg0 = op->arg(0);
221 if (arg0 != NULL && (strlen(arg0) > 0)) {
222 if (strcmp(arg0, "-all") != 0 && strcmp(arg0, "-live") != 0) {
223 out->print_cr("Invalid argument to inspectheap operation: %s", arg0);
224 return JNI_ERR;
225 }
226 live_objects_only = strcmp(arg0, "-live") == 0;
227 }
228 VM_GC_HeapInspection heapop(out, live_objects_only /* request full gc */);
229 VMThread::execute(&heapop);
230 return JNI_OK;
231 }
232
233 // set a boolean global flag using value from AttachOperation
234 static jint set_bool_flag(const char* name, AttachOperation* op, outputStream* out) {
235 bool value = true;
236 const char* arg1;
237 if ((arg1 = op->arg(1)) != NULL) {
238 int tmp;
239 int n = sscanf(arg1, "%d", &tmp);
240 if (n != 1) {
241 out->print_cr("flag value must be a boolean (1 or 0)");
242 return JNI_ERR;
243 }
244 value = (tmp != 0);
245 }
246 bool res = CommandLineFlags::boolAtPut((char*)name, &value, Flag::ATTACH_ON_DEMAND);
247 if (! res) {
248 out->print_cr("setting flag %s failed", name);
249 }
250 return res? JNI_OK : JNI_ERR;
251 }
252
253 // set a intx global flag using value from AttachOperation
254 static jint set_intx_flag(const char* name, AttachOperation* op, outputStream* out) {
255 intx value;
256 const char* arg1;
257 if ((arg1 = op->arg(1)) != NULL) {
258 int n = sscanf(arg1, INTX_FORMAT, &value);
259 if (n != 1) {
260 out->print_cr("flag value must be an integer");
261 return JNI_ERR;
262 }
263 }
264 bool res = CommandLineFlags::intxAtPut((char*)name, &value, Flag::ATTACH_ON_DEMAND);
265 if (! res) {
266 out->print_cr("setting flag %s failed", name);
267 }
268
269 return res? JNI_OK : JNI_ERR;
270 }
271
272 // set a uintx global flag using value from AttachOperation
273 static jint set_uintx_flag(const char* name, AttachOperation* op, outputStream* out) {
274 uintx value;
275 const char* arg1;
276 if ((arg1 = op->arg(1)) != NULL) {
277 int n = sscanf(arg1, UINTX_FORMAT, &value);
278 if (n != 1) {
279 out->print_cr("flag value must be an unsigned integer");
280 return JNI_ERR;
281 }
282 }
283
284 if (strncmp(name, "MaxHeapFreeRatio", 17) == 0) {
285 FormatBuffer<80> err_msg("%s", "");
286 if (!Arguments::verify_MaxHeapFreeRatio(err_msg, value)) {
287 out->print_cr("%s", err_msg.buffer());
288 return JNI_ERR;
289 }
290 } else if (strncmp(name, "MinHeapFreeRatio", 17) == 0) {
291 FormatBuffer<80> err_msg("%s", "");
292 if (!Arguments::verify_MinHeapFreeRatio(err_msg, value)) {
293 out->print_cr("%s", err_msg.buffer());
294 return JNI_ERR;
295 }
296 }
297 bool res = CommandLineFlags::uintxAtPut((char*)name, &value, Flag::ATTACH_ON_DEMAND);
298 if (! res) {
299 out->print_cr("setting flag %s failed", name);
300 }
301
302 return res? JNI_OK : JNI_ERR;
303 }
304
305 // set a uint64_t global flag using value from AttachOperation
306 static jint set_uint64_t_flag(const char* name, AttachOperation* op, outputStream* out) {
307 uint64_t value;
308 const char* arg1;
309 if ((arg1 = op->arg(1)) != NULL) {
310 int n = sscanf(arg1, UINT64_FORMAT, &value);
311 if (n != 1) {
312 out->print_cr("flag value must be an unsigned 64-bit integer");
313 return JNI_ERR;
314 }
315 }
316 bool res = CommandLineFlags::uint64_tAtPut((char*)name, &value, Flag::ATTACH_ON_DEMAND);
317 if (! res) {
318 out->print_cr("setting flag %s failed", name);
319 }
320
321 return res? JNI_OK : JNI_ERR;
322 }
323
324 // set a size_t global flag using value from AttachOperation
325 static jint set_size_t_flag(const char* name, AttachOperation* op, outputStream* out) {
326 size_t value;
327 const char* arg1;
328 if ((arg1 = op->arg(1)) != NULL) {
329 int n = sscanf(arg1, SIZE_FORMAT, &value);
330 if (n != 1) {
331 out->print_cr("flag value must be an unsigned integer");
332 return JNI_ERR;
333 }
334 }
335 bool res = CommandLineFlags::size_tAtPut((char*)name, &value, Flag::ATTACH_ON_DEMAND);
336 if (! res) {
337 out->print_cr("setting flag %s failed", name);
338 }
339
340 return res? JNI_OK : JNI_ERR;
341 }
342
343 // set a string global flag using value from AttachOperation
344 static jint set_ccstr_flag(const char* name, AttachOperation* op, outputStream* out) {
345 const char* value;
346 if ((value = op->arg(1)) == NULL) {
347 out->print_cr("flag value must be a string");
348 return JNI_ERR;
349 }
350 bool res = CommandLineFlags::ccstrAtPut((char*)name, &value, Flag::ATTACH_ON_DEMAND);
351 if (res) {
352 FREE_C_HEAP_ARRAY(char, value);
353 } else {
354 out->print_cr("setting flag %s failed", name);
355 }
356
357 return res? JNI_OK : JNI_ERR;
358 }
359
360 // Implementation of "setflag" command
361 static jint set_flag(AttachOperation* op, outputStream* out) {
362
363 const char* name = NULL;
364 if ((name = op->arg(0)) == NULL) {
365 out->print_cr("flag name is missing");
366 return JNI_ERR;
367 }
368
369 Flag* f = Flag::find_flag((char*)name, strlen(name));
370 if (f && f->is_external() && f->is_writeable()) {
371 if (f->is_bool()) {
372 return set_bool_flag(name, op, out);
373 } else if (f->is_intx()) {
374 return set_intx_flag(name, op, out);
375 } else if (f->is_uintx()) {
376 return set_uintx_flag(name, op, out);
377 } else if (f->is_uint64_t()) {
378 return set_uint64_t_flag(name, op, out);
379 } else if (f->is_size_t()) {
380 return set_size_t_flag(name, op, out);
381 } else if (f->is_ccstr()) {
382 return set_ccstr_flag(name, op, out);
383 } else {
384 ShouldNotReachHere();
385 return JNI_ERR;
386 }
387 } else {
388 return AttachListener::pd_set_flag(op, out);
389 }
390 }
391
392 // Implementation of "printflag" command
393 // See also: PrintVMFlagsDCmd class
394 static jint print_flag(AttachOperation* op, outputStream* out) {
395 const char* name = NULL;
396 if ((name = op->arg(0)) == NULL) {
397 out->print_cr("flag name is missing");
398 return JNI_ERR;
399 }
400 Flag* f = Flag::find_flag((char*)name, strlen(name));
401 if (f) {
402 f->print_as_flag(out);
403 out->cr();
404 } else {
405 out->print_cr("no such flag '%s'", name);
406 }
407 return JNI_OK;
408 }
409
410 // Table to map operation names to functions.
411
412 // names must be of length <= AttachOperation::name_length_max
413 static AttachOperationFunctionInfo funcs[] = {
414 { "agentProperties", get_agent_properties },
415 { "datadump", data_dump },
416 { "dumpheap", dump_heap },
417 { "load", JvmtiExport::load_agent_library },
418 { "properties", get_system_properties },
419 { "threaddump", thread_dump },
420 { "inspectheap", heap_inspection },
421 { "setflag", set_flag },
422 { "printflag", print_flag },
423 { "jcmd", jcmd },
424 { NULL, NULL }
425 };
426
427
428
429 // The Attach Listener threads services a queue. It dequeues an operation
430 // from the queue, examines the operation name (command), and dispatches
431 // to the corresponding function to perform the operation.
432
433 static void attach_listener_thread_entry(JavaThread* thread, TRAPS) {
434 os::set_priority(thread, NearMaxPriority);
435
436 thread->record_stack_base_and_size();
437
438 if (AttachListener::pd_init() != 0) {
439 return;
440 }
441 AttachListener::set_initialized();
442
443 for (;;) {
444 AttachOperation* op = AttachListener::dequeue();
445 if (op == NULL) {
446 return; // dequeue failed or shutdown
447 }
448
449 ResourceMark rm;
450 bufferedStream st;
451 jint res = JNI_OK;
452
453 // handle special detachall operation
454 if (strcmp(op->name(), AttachOperation::detachall_operation_name()) == 0) {
455 AttachListener::detachall();
456 } else {
457 // find the function to dispatch too
458 AttachOperationFunctionInfo* info = NULL;
459 for (int i=0; funcs[i].name != NULL; i++) {
460 const char* name = funcs[i].name;
461 assert(strlen(name) <= AttachOperation::name_length_max, "operation <= name_length_max");
462 if (strcmp(op->name(), name) == 0) {
463 info = &(funcs[i]);
464 break;
465 }
466 }
467
468 // check for platform dependent attach operation
469 if (info == NULL) {
470 info = AttachListener::pd_find_operation(op->name());
471 }
472
473 if (info != NULL) {
474 // dispatch to the function that implements this operation
475 res = (info->func)(op, &st);
476 } else {
477 st.print("Operation %s not recognized!", op->name());
478 res = JNI_ERR;
479 }
480 }
481
482 // operation complete - send result and output to client
483 op->complete(res, &st);
484 }
485 }
486
487 bool AttachListener::has_init_error(TRAPS) {
488 if (HAS_PENDING_EXCEPTION) {
489 tty->print_cr("Exception in VM (AttachListener::init) : ");
490 java_lang_Throwable::print(PENDING_EXCEPTION, tty);
491 tty->cr();
492
493 CLEAR_PENDING_EXCEPTION;
494
495 return true;
496 } else {
497 return false;
498 }
499 }
500
501 // Starts the Attach Listener thread
502 void AttachListener::init() {
503 EXCEPTION_MARK;
504 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, THREAD);
505 if (has_init_error(THREAD)) {
506 return;
507 }
508
509 instanceKlassHandle klass (THREAD, k);
510 instanceHandle thread_oop = klass->allocate_instance_handle(THREAD);
511 if (has_init_error(THREAD)) {
512 return;
513 }
514
515 const char thread_name[] = "Attach Listener";
516 Handle string = java_lang_String::create_from_str(thread_name, THREAD);
517 if (has_init_error(THREAD)) {
518 return;
519 }
520
521 // Initialize thread_oop to put it into the system threadGroup
522 Handle thread_group (THREAD, Universe::system_thread_group());
523 JavaValue result(T_VOID);
524 JavaCalls::call_special(&result, thread_oop,
525 klass,
526 vmSymbols::object_initializer_name(),
527 vmSymbols::threadgroup_string_void_signature(),
528 thread_group,
529 string,
530 THREAD);
531
532 if (has_init_error(THREAD)) {
533 return;
534 }
535
536 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
537 JavaCalls::call_special(&result,
538 thread_group,
539 group,
540 vmSymbols::add_method_name(),
541 vmSymbols::thread_void_signature(),
542 thread_oop, // ARG 1
543 THREAD);
544 if (has_init_error(THREAD)) {
545 return;
546 }
547
548 { MutexLocker mu(Threads_lock);
549 JavaThread* listener_thread = new JavaThread(&attach_listener_thread_entry);
550
551 // Check that thread and osthread were created
552 if (listener_thread == NULL || listener_thread->osthread() == NULL) {
553 vm_exit_during_initialization("java.lang.OutOfMemoryError",
554 os::native_thread_creation_failed_msg());
555 }
556
557 java_lang_Thread::set_thread(thread_oop(), listener_thread);
558 java_lang_Thread::set_daemon(thread_oop());
559
560 listener_thread->set_threadObj(thread_oop());
561 Threads::add(listener_thread);
562 Thread::start(listener_thread);
563 }
564 }
565
566 // Performs clean-up tasks on platforms where we can detect that the last
567 // client has detached
568 void AttachListener::detachall() {
569 // call the platform dependent clean-up
570 pd_detachall();
571 }