1 /*
2 * Copyright (c) 2005, 2016, 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 "prims/jvmtiExport.hpp"
31 #include "runtime/arguments.hpp"
32 #include "runtime/globals.hpp"
33 #include "runtime/java.hpp"
34 #include "runtime/javaCalls.hpp"
35 #include "runtime/os.hpp"
36 #include "services/attachListener.hpp"
37 #include "services/diagnosticCommand.hpp"
38 #include "services/heapDumper.hpp"
39
40 volatile bool AttachListener::_initialized;
41
42 // Implementation of "properties" command.
43 //
44 // Invokes sun.misc.VMSupport.serializePropertiesToByteArray to serialize
45 // the system properties into a byte array.
46
47 static Klass* load_and_initialize_klass(Symbol* sh, TRAPS) {
48 Klass* k = SystemDictionary::resolve_or_fail(sh, true, CHECK_NULL);
49 instanceKlassHandle ik (THREAD, k);
50 if (ik->should_be_initialized()) {
51 ik->initialize(CHECK_NULL);
52 }
53 return ik();
54 }
55
56 static jint get_properties(AttachOperation* op, outputStream* out, Symbol* serializePropertiesMethod) {
57 Thread* THREAD = Thread::current();
58 HandleMark hm;
59
60 // load sun.misc.VMSupport
61 Symbol* klass = vmSymbols::sun_misc_VMSupport();
62 Klass* k = load_and_initialize_klass(klass, THREAD);
63 if (HAS_PENDING_EXCEPTION) {
64 java_lang_Throwable::print(PENDING_EXCEPTION, out);
65 CLEAR_PENDING_EXCEPTION;
66 return JNI_ERR;
67 }
68 instanceKlassHandle ik(THREAD, k);
69
70 // invoke the serializePropertiesToByteArray method
71 JavaValue result(T_OBJECT);
72 JavaCallArguments args;
73
74
75 Symbol* signature = vmSymbols::serializePropertiesToByteArray_signature();
76 JavaCalls::call_static(&result,
77 ik,
78 serializePropertiesMethod,
79 signature,
80 &args,
81 THREAD);
82 if (HAS_PENDING_EXCEPTION) {
83 java_lang_Throwable::print(PENDING_EXCEPTION, out);
84 CLEAR_PENDING_EXCEPTION;
85 return JNI_ERR;
86 }
87
88 // The result should be a [B
89 oop res = (oop)result.get_jobject();
90 assert(res->is_typeArray(), "just checking");
91 assert(TypeArrayKlass::cast(res->klass())->element_type() == T_BYTE, "just checking");
92
93 // copy the bytes to the output stream
94 typeArrayOop ba = typeArrayOop(res);
95 jbyte* addr = typeArrayOop(res)->byte_at_addr(0);
96 out->print_raw((const char*)addr, ba->length());
97
98 return JNI_OK;
99 }
100
101 // Implementation of "properties" command.
102 // See also: PrintSystemPropertiesDCmd class
103 static jint get_system_properties(AttachOperation* op, outputStream* out) {
104 return get_properties(op, out, vmSymbols::serializePropertiesToByteArray_name());
105 }
106
107 // Implementation of "agent_properties" command.
108 static jint get_agent_properties(AttachOperation* op, outputStream* out) {
109 return get_properties(op, out, vmSymbols::serializeAgentPropertiesToByteArray_name());
110 }
111
112 // Implementation of "datadump" command.
113 //
114 // Raises a SIGBREAK signal so that VM dump threads, does deadlock detection,
115 // etc. In theory this command should only post a DataDumpRequest to any
116 // JVMTI environment that has enabled this event. However it's useful to
117 // trigger the SIGBREAK handler.
118
119 static jint data_dump(AttachOperation* op, outputStream* out) {
120 if (!ReduceSignalUsage) {
121 AttachListener::pd_data_dump();
122 } else {
123 if (JvmtiExport::should_post_data_dump()) {
124 JvmtiExport::post_data_dump();
125 }
126 }
127 return JNI_OK;
128 }
129
130 // Implementation of "threaddump" command - essentially a remote ctrl-break
131 // See also: ThreadDumpDCmd class
132 //
133 static jint thread_dump(AttachOperation* op, outputStream* out) {
134 bool print_concurrent_locks = false;
135 if (op->arg(0) != NULL && strcmp(op->arg(0), "-l") == 0) {
136 print_concurrent_locks = true;
137 }
138
139 // thread stacks
140 VM_PrintThreads op1(out, print_concurrent_locks);
141 VMThread::execute(&op1);
142
143 // JNI global handles
144 VM_PrintJNI op2(out);
145 VMThread::execute(&op2);
146
147 // Deadlock detection
148 VM_FindDeadlocks op3(out);
149 VMThread::execute(&op3);
150
151 return JNI_OK;
152 }
153
154 // A jcmd attach operation request was received, which will now
155 // dispatch to the diagnostic commands used for serviceability functions.
156 static jint jcmd(AttachOperation* op, outputStream* out) {
157 Thread* THREAD = Thread::current();
158 // All the supplied jcmd arguments are stored as a single
159 // string (op->arg(0)). This is parsed by the Dcmd framework.
160 DCmd::parse_and_execute(DCmd_Source_AttachAPI, out, op->arg(0), ' ', THREAD);
161 if (HAS_PENDING_EXCEPTION) {
162 java_lang_Throwable::print(PENDING_EXCEPTION, out);
163 out->cr();
164 CLEAR_PENDING_EXCEPTION;
165 return JNI_ERR;
166 }
167 return JNI_OK;
168 }
169
170 // Implementation of "dumpheap" command.
171 // See also: HeapDumpDCmd class
172 //
173 // Input arguments :-
174 // arg0: Name of the dump file
175 // arg1: "-live" or "-all"
176 jint dump_heap(AttachOperation* op, outputStream* out) {
177 const char* path = op->arg(0);
178 if (path == NULL || path[0] == '\0') {
179 out->print_cr("No dump file specified");
180 } else {
181 bool live_objects_only = true; // default is true to retain the behavior before this change is made
182 const char* arg1 = op->arg(1);
183 if (arg1 != NULL && (strlen(arg1) > 0)) {
184 if (strcmp(arg1, "-all") != 0 && strcmp(arg1, "-live") != 0) {
185 out->print_cr("Invalid argument to dumpheap operation: %s", arg1);
186 return JNI_ERR;
187 }
188 live_objects_only = strcmp(arg1, "-live") == 0;
189 }
190
191 // Request a full GC before heap dump if live_objects_only = true
192 // This helps reduces the amount of unreachable objects in the dump
193 // and makes it easier to browse.
194 HeapDumper dumper(live_objects_only /* request GC */);
195 int res = dumper.dump(op->arg(0));
196 if (res == 0) {
197 out->print_cr("Heap dump file created");
198 } else {
199 // heap dump failed
200 ResourceMark rm;
201 char* error = dumper.error_as_C_string();
202 if (error == NULL) {
203 out->print_cr("Dump failed - reason unknown");
204 } else {
205 out->print_cr("%s", error);
206 }
207 }
208 }
209 return JNI_OK;
210 }
211
212 // Implementation of "inspectheap" command
213 // See also: ClassHistogramDCmd class
214 //
215 // Input arguments :-
216 // arg0: "-live" or "-all"
217 static jint heap_inspection(AttachOperation* op, outputStream* out) {
218 bool live_objects_only = true; // default is true to retain the behavior before this change is made
219 const char* arg0 = op->arg(0);
220 if (arg0 != NULL && (strlen(arg0) > 0)) {
221 if (strcmp(arg0, "-all") != 0 && strcmp(arg0, "-live") != 0) {
222 out->print_cr("Invalid argument to inspectheap operation: %s", arg0);
223 return JNI_ERR;
224 }
225 live_objects_only = strcmp(arg0, "-live") == 0;
226 }
227 VM_GC_HeapInspection heapop(out, live_objects_only /* request full gc */);
228 VMThread::execute(&heapop);
229 return JNI_OK;
230 }
231
232 // set a boolean global flag using value from AttachOperation
233 static jint set_bool_flag(const char* name, AttachOperation* op, outputStream* out) {
234 bool value = true;
235 const char* arg1;
236 if ((arg1 = op->arg(1)) != NULL) {
237 int tmp;
238 int n = sscanf(arg1, "%d", &tmp);
239 if (n != 1) {
240 out->print_cr("flag value must be a boolean (1 or 0)");
241 return JNI_ERR;
242 }
243 value = (tmp != 0);
244 }
245 bool res = CommandLineFlags::boolAtPut((char*)name, &value, Flag::ATTACH_ON_DEMAND);
246 if (! res) {
247 out->print_cr("setting flag %s failed", name);
248 }
249 return res? JNI_OK : JNI_ERR;
250 }
251
252 // set a intx global flag using value from AttachOperation
253 static jint set_intx_flag(const char* name, AttachOperation* op, outputStream* out) {
254 intx value;
255 const char* arg1;
256 if ((arg1 = op->arg(1)) != NULL) {
257 int n = sscanf(arg1, INTX_FORMAT, &value);
258 if (n != 1) {
259 out->print_cr("flag value must be an integer");
260 return JNI_ERR;
261 }
262 }
263 bool res = CommandLineFlags::intxAtPut((char*)name, &value, Flag::ATTACH_ON_DEMAND);
264 if (! res) {
265 out->print_cr("setting flag %s failed", name);
266 }
267
268 return res? JNI_OK : JNI_ERR;
269 }
270
271 // set a uintx global flag using value from AttachOperation
272 static jint set_uintx_flag(const char* name, AttachOperation* op, outputStream* out) {
273 uintx value;
274
275 const char* arg1 = op->arg(1);
276 if (arg1 == NULL) {
277 out->print_cr("flag value must be specified");
278 return JNI_ERR;
279 }
280
281 int n = sscanf(arg1, UINTX_FORMAT, &value);
282 if (n != 1) {
283 out->print_cr("flag value must be an unsigned integer");
284 return JNI_ERR;
285 }
286
287 if (strncmp(name, "MaxHeapFreeRatio", 17) == 0) {
288 FormatBuffer<80> err_msg("%s", "");
289 if (!Arguments::verify_MaxHeapFreeRatio(err_msg, value)) {
290 out->print_cr("%s", err_msg.buffer());
291 return JNI_ERR;
292 }
293 } else if (strncmp(name, "MinHeapFreeRatio", 17) == 0) {
294 FormatBuffer<80> err_msg("%s", "");
295 if (!Arguments::verify_MinHeapFreeRatio(err_msg, value)) {
296 out->print_cr("%s", err_msg.buffer());
297 return JNI_ERR;
298 }
299 }
300 bool res = CommandLineFlags::uintxAtPut((char*)name, &value, Flag::ATTACH_ON_DEMAND);
301 if (! res) {
302 out->print_cr("setting flag %s failed", name);
303 }
304
305 return res? JNI_OK : JNI_ERR;
306 }
307
308 // set a uint64_t global flag using value from AttachOperation
309 static jint set_uint64_t_flag(const char* name, AttachOperation* op, outputStream* out) {
310 uint64_t value;
311 const char* arg1;
312 if ((arg1 = op->arg(1)) != NULL) {
313 int n = sscanf(arg1, UINT64_FORMAT, &value);
314 if (n != 1) {
315 out->print_cr("flag value must be an unsigned 64-bit integer");
316 return JNI_ERR;
317 }
318 }
319 bool res = CommandLineFlags::uint64_tAtPut((char*)name, &value, Flag::ATTACH_ON_DEMAND);
320 if (! res) {
321 out->print_cr("setting flag %s failed", name);
322 }
323
324 return res? JNI_OK : JNI_ERR;
325 }
326
327 // set a string global flag using value from AttachOperation
328 static jint set_ccstr_flag(const char* name, AttachOperation* op, outputStream* out) {
329 const char* value;
330 if ((value = op->arg(1)) == NULL) {
331 out->print_cr("flag value must be a string");
332 return JNI_ERR;
333 }
334 bool res = CommandLineFlags::ccstrAtPut((char*)name, &value, Flag::ATTACH_ON_DEMAND);
335 if (res) {
336 FREE_C_HEAP_ARRAY(char, value, mtInternal);
337 } else {
338 out->print_cr("setting flag %s failed", name);
339 }
340
341 return res? JNI_OK : JNI_ERR;
342 }
343
344 // Implementation of "setflag" command
345 static jint set_flag(AttachOperation* op, outputStream* out) {
346
347 const char* name = NULL;
348 if ((name = op->arg(0)) == NULL) {
349 out->print_cr("flag name is missing");
350 return JNI_ERR;
351 }
352
353 Flag* f = Flag::find_flag((char*)name, strlen(name));
354 if (f && f->is_external() && f->is_writeable()) {
355 if (f->is_bool()) {
356 return set_bool_flag(name, op, out);
357 } else if (f->is_intx()) {
358 return set_intx_flag(name, op, out);
359 } else if (f->is_uintx()) {
360 return set_uintx_flag(name, op, out);
361 } else if (f->is_uint64_t()) {
362 return set_uint64_t_flag(name, op, out);
363 } else if (f->is_ccstr()) {
364 return set_ccstr_flag(name, op, out);
365 } else {
366 ShouldNotReachHere();
367 return JNI_ERR;
368 }
369 } else {
370 return AttachListener::pd_set_flag(op, out);
371 }
372 }
373
374 // Implementation of "printflag" command
375 // See also: PrintVMFlagsDCmd class
376 static jint print_flag(AttachOperation* op, outputStream* out) {
377 const char* name = NULL;
378 if ((name = op->arg(0)) == NULL) {
379 out->print_cr("flag name is missing");
380 return JNI_ERR;
381 }
382 Flag* f = Flag::find_flag((char*)name, strlen(name));
383 if (f) {
384 f->print_as_flag(out);
385 out->cr();
386 } else {
387 out->print_cr("no such flag '%s'", name);
388 }
389 return JNI_OK;
390 }
391
392 // Table to map operation names to functions.
393
394 // names must be of length <= AttachOperation::name_length_max
395 static AttachOperationFunctionInfo funcs[] = {
396 { "agentProperties", get_agent_properties },
397 { "datadump", data_dump },
398 { "dumpheap", dump_heap },
399 { "load", JvmtiExport::load_agent_library },
400 { "properties", get_system_properties },
401 { "threaddump", thread_dump },
402 { "inspectheap", heap_inspection },
403 { "setflag", set_flag },
404 { "printflag", print_flag },
405 { "jcmd", jcmd },
406 { NULL, NULL }
407 };
408
409
410
411 // The Attach Listener threads services a queue. It dequeues an operation
412 // from the queue, examines the operation name (command), and dispatches
413 // to the corresponding function to perform the operation.
414
415 static void attach_listener_thread_entry(JavaThread* thread, TRAPS) {
416 os::set_priority(thread, NearMaxPriority);
417
418 thread->record_stack_base_and_size();
419
420 if (AttachListener::pd_init() != 0) {
421 return;
422 }
423 AttachListener::set_initialized();
424
425 for (;;) {
426 AttachOperation* op = AttachListener::dequeue();
427 if (op == NULL) {
428 return; // dequeue failed or shutdown
429 }
430
431 ResourceMark rm;
432 bufferedStream st;
433 jint res = JNI_OK;
434
435 // handle special detachall operation
436 if (strcmp(op->name(), AttachOperation::detachall_operation_name()) == 0) {
437 AttachListener::detachall();
438 } else {
439 // find the function to dispatch too
440 AttachOperationFunctionInfo* info = NULL;
441 for (int i=0; funcs[i].name != NULL; i++) {
442 const char* name = funcs[i].name;
443 assert(strlen(name) <= AttachOperation::name_length_max, "operation <= name_length_max");
444 if (strcmp(op->name(), name) == 0) {
445 info = &(funcs[i]);
446 break;
447 }
448 }
449
450 // check for platform dependent attach operation
451 if (info == NULL) {
452 info = AttachListener::pd_find_operation(op->name());
453 }
454
455 if (info != NULL) {
456 // dispatch to the function that implements this operation
457 res = (info->func)(op, &st);
458 } else {
459 st.print("Operation %s not recognized!", op->name());
460 res = JNI_ERR;
461 }
462 }
463
464 // operation complete - send result and output to client
465 op->complete(res, &st);
466 }
467 }
468
469 // Starts the Attach Listener thread
470 void AttachListener::init() {
471 EXCEPTION_MARK;
472 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
473 instanceKlassHandle klass (THREAD, k);
474 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
475
476 const char thread_name[] = "Attach Listener";
477 Handle string = java_lang_String::create_from_str(thread_name, CHECK);
478
479 // Initialize thread_oop to put it into the system threadGroup
480 Handle thread_group (THREAD, Universe::system_thread_group());
481 JavaValue result(T_VOID);
482 JavaCalls::call_special(&result, thread_oop,
483 klass,
484 vmSymbols::object_initializer_name(),
485 vmSymbols::threadgroup_string_void_signature(),
486 thread_group,
487 string,
488 THREAD);
489
490 if (HAS_PENDING_EXCEPTION) {
491 tty->print_cr("Exception in VM (AttachListener::init) : ");
492 java_lang_Throwable::print(PENDING_EXCEPTION, tty);
493 tty->cr();
494
495 CLEAR_PENDING_EXCEPTION;
496
497 return;
498 }
499
500 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
501 JavaCalls::call_special(&result,
502 thread_group,
503 group,
504 vmSymbols::add_method_name(),
505 vmSymbols::thread_void_signature(),
506 thread_oop, // ARG 1
507 THREAD);
508
509 if (HAS_PENDING_EXCEPTION) {
510 tty->print_cr("Exception in VM (AttachListener::init) : ");
511 java_lang_Throwable::print(PENDING_EXCEPTION, tty);
512 tty->cr();
513
514 CLEAR_PENDING_EXCEPTION;
515
516 return;
517 }
518
519 { MutexLocker mu(Threads_lock);
520 JavaThread* listener_thread = new JavaThread(&attach_listener_thread_entry);
521
522 // Check that thread and osthread were created
523 if (listener_thread == NULL || listener_thread->osthread() == NULL) {
524 vm_exit_during_initialization("java.lang.OutOfMemoryError",
525 "unable to create new native thread");
526 }
527
528 java_lang_Thread::set_thread(thread_oop(), listener_thread);
529 java_lang_Thread::set_daemon(thread_oop());
530
531 listener_thread->set_threadObj(thread_oop());
532 Threads::add(listener_thread);
533 Thread::start(listener_thread);
534 }
535 }
536
537 // Performs clean-up tasks on platforms where we can detect that the last
538 // client has detached
539 void AttachListener::detachall() {
540 // call the platform dependent clean-up
541 pd_detachall();
542 }