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