1 /*
2 * Copyright (c) 2005, 2020, 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 dumper.dump(op->arg(0), out);
241 }
242 return JNI_OK;
243 }
244
245 // Implementation of "inspectheap" command
246 // See also: ClassHistogramDCmd class
247 //
248 // Input arguments :-
249 // arg0: "-live" or "-all"
250 // arg1: Name of the dump file or NULL
251 // arg2: parallel thread number
252 static jint heap_inspection(AttachOperation* op, outputStream* out) {
253 bool live_objects_only = true; // default is true to retain the behavior before this change is made
254 outputStream* os = out; // if path not specified or path is NULL, use out
255 fileStream* fs = NULL;
256 const char* arg0 = op->arg(0);
257 uint parallel_thread_num = MAX(1, (uint)os::initial_active_processor_count() * 3 / 8);
258 if (arg0 != NULL && (strlen(arg0) > 0)) {
259 if (strcmp(arg0, "-all") != 0 && strcmp(arg0, "-live") != 0) {
260 out->print_cr("Invalid argument to inspectheap operation: %s", arg0);
261 return JNI_ERR;
262 }
263 live_objects_only = strcmp(arg0, "-live") == 0;
264 }
265
266 const char* path = op->arg(1);
267 if (path != NULL && path[0] != '\0') {
268 // create file
269 fs = new (ResourceObj::C_HEAP, mtInternal) fileStream(path);
270 if (fs == NULL) {
271 out->print_cr("Failed to allocate space for file: %s", path);
272 }
273 os = fs;
274 }
275
276 const char* num_str = op->arg(2);
277 if (num_str != NULL && num_str[0] != '\0') {
278 uintx num;
279 if (!Arguments::parse_uintx(num_str, &num, 0)) {
280 out->print_cr("Invalid parallel thread number: [%s]", num_str);
281 return JNI_ERR;
282 }
283 parallel_thread_num = num == 0 ? parallel_thread_num : (uint)num;
284 }
285
286 VM_GC_HeapInspection heapop(os, live_objects_only /* request full gc */, parallel_thread_num);
287 VMThread::execute(&heapop);
288 if (os != NULL && os != out) {
289 out->print_cr("Heap inspection file created: %s", path);
290 delete fs;
291 }
292 return JNI_OK;
293 }
294
295 // Implementation of "setflag" command
296 static jint set_flag(AttachOperation* op, outputStream* out) {
297
298 const char* name = NULL;
299 if ((name = op->arg(0)) == NULL) {
300 out->print_cr("flag name is missing");
301 return JNI_ERR;
302 }
303
304 FormatBuffer<80> err_msg("%s", "");
305
306 int ret = WriteableFlags::set_flag(op->arg(0), op->arg(1), JVMFlag::ATTACH_ON_DEMAND, err_msg);
307 if (ret != JVMFlag::SUCCESS) {
308 if (ret == JVMFlag::NON_WRITABLE) {
309 // if the flag is not manageable try to change it through
310 // the platform dependent implementation
311 return AttachListener::pd_set_flag(op, out);
312 } else {
313 out->print_cr("%s", err_msg.buffer());
314 }
315
316 return JNI_ERR;
317 }
318 return JNI_OK;
319 }
320
321 // Implementation of "printflag" command
322 // See also: PrintVMFlagsDCmd class
323 static jint print_flag(AttachOperation* op, outputStream* out) {
324 const char* name = NULL;
325 if ((name = op->arg(0)) == NULL) {
326 out->print_cr("flag name is missing");
327 return JNI_ERR;
328 }
329 JVMFlag* f = JVMFlag::find_flag(name);
330 if (f) {
331 f->print_as_flag(out);
332 out->cr();
333 } else {
334 out->print_cr("no such flag '%s'", name);
335 }
336 return JNI_OK;
337 }
338
339 // Table to map operation names to functions.
340
341 // names must be of length <= AttachOperation::name_length_max
342 static AttachOperationFunctionInfo funcs[] = {
343 { "agentProperties", get_agent_properties },
344 { "datadump", data_dump },
345 { "dumpheap", dump_heap },
346 { "load", load_agent },
347 { "properties", get_system_properties },
348 { "threaddump", thread_dump },
349 { "inspectheap", heap_inspection },
350 { "setflag", set_flag },
351 { "printflag", print_flag },
352 { "jcmd", jcmd },
353 { NULL, NULL }
354 };
355
356
357
358 // The Attach Listener threads services a queue. It dequeues an operation
359 // from the queue, examines the operation name (command), and dispatches
360 // to the corresponding function to perform the operation.
361
362 static void attach_listener_thread_entry(JavaThread* thread, TRAPS) {
363 os::set_priority(thread, NearMaxPriority);
364
365 assert(thread == Thread::current(), "Must be");
366 assert(thread->stack_base() != NULL && thread->stack_size() > 0,
367 "Should already be setup");
368
369 if (AttachListener::pd_init() != 0) {
370 AttachListener::set_state(AL_NOT_INITIALIZED);
371 return;
372 }
373 AttachListener::set_initialized();
374
375 for (;;) {
376 AttachOperation* op = AttachListener::dequeue();
377 if (op == NULL) {
378 AttachListener::set_state(AL_NOT_INITIALIZED);
379 return; // dequeue failed or shutdown
380 }
381
382 ResourceMark rm;
383 bufferedStream st;
384 jint res = JNI_OK;
385
386 // handle special detachall operation
387 if (strcmp(op->name(), AttachOperation::detachall_operation_name()) == 0) {
388 AttachListener::detachall();
389 } else if (!EnableDynamicAgentLoading && strcmp(op->name(), "load") == 0) {
390 st.print("Dynamic agent loading is not enabled. "
391 "Use -XX:+EnableDynamicAgentLoading to launch target VM.");
392 res = JNI_ERR;
393 } else {
394 // find the function to dispatch too
395 AttachOperationFunctionInfo* info = NULL;
396 for (int i=0; funcs[i].name != NULL; i++) {
397 const char* name = funcs[i].name;
398 assert(strlen(name) <= AttachOperation::name_length_max, "operation <= name_length_max");
399 if (strcmp(op->name(), name) == 0) {
400 info = &(funcs[i]);
401 break;
402 }
403 }
404
405 // check for platform dependent attach operation
406 if (info == NULL) {
407 info = AttachListener::pd_find_operation(op->name());
408 }
409
410 if (info != NULL) {
411 // dispatch to the function that implements this operation
412 res = (info->func)(op, &st);
413 } else {
414 st.print("Operation %s not recognized!", op->name());
415 res = JNI_ERR;
416 }
417 }
418
419 // operation complete - send result and output to client
420 op->complete(res, &st);
421 }
422
423 ShouldNotReachHere();
424 }
425
426 bool AttachListener::has_init_error(TRAPS) {
427 if (HAS_PENDING_EXCEPTION) {
428 tty->print_cr("Exception in VM (AttachListener::init) : ");
429 java_lang_Throwable::print(PENDING_EXCEPTION, tty);
430 tty->cr();
431
432 CLEAR_PENDING_EXCEPTION;
433
434 return true;
435 } else {
436 return false;
437 }
438 }
439
440 // Starts the Attach Listener thread
441 void AttachListener::init() {
442 EXCEPTION_MARK;
443
444 const char thread_name[] = "Attach Listener";
445 Handle string = java_lang_String::create_from_str(thread_name, THREAD);
446 if (has_init_error(THREAD)) {
447 set_state(AL_NOT_INITIALIZED);
448 return;
449 }
450
451 // Initialize thread_oop to put it into the system threadGroup
452 Handle thread_group (THREAD, Universe::system_thread_group());
453 Handle thread_oop = JavaCalls::construct_new_instance(SystemDictionary::Thread_klass(),
454 vmSymbols::threadgroup_string_void_signature(),
455 thread_group,
456 string,
457 THREAD);
458 if (has_init_error(THREAD)) {
459 set_state(AL_NOT_INITIALIZED);
460 return;
461 }
462
463 Klass* group = SystemDictionary::ThreadGroup_klass();
464 JavaValue result(T_VOID);
465 JavaCalls::call_special(&result,
466 thread_group,
467 group,
468 vmSymbols::add_method_name(),
469 vmSymbols::thread_void_signature(),
470 thread_oop,
471 THREAD);
472 if (has_init_error(THREAD)) {
473 set_state(AL_NOT_INITIALIZED);
474 return;
475 }
476
477 { MutexLocker mu(THREAD, Threads_lock);
478 JavaThread* listener_thread = new JavaThread(&attach_listener_thread_entry);
479
480 // Check that thread and osthread were created
481 if (listener_thread == NULL || listener_thread->osthread() == NULL) {
482 vm_exit_during_initialization("java.lang.OutOfMemoryError",
483 os::native_thread_creation_failed_msg());
484 }
485
486 java_lang_Thread::set_thread(thread_oop(), listener_thread);
487 java_lang_Thread::set_daemon(thread_oop());
488
489 listener_thread->set_threadObj(thread_oop());
490 Threads::add(listener_thread);
491 Thread::start(listener_thread);
492 }
493 }
494
495 // Performs clean-up tasks on platforms where we can detect that the last
496 // client has detached
497 void AttachListener::detachall() {
498 // call the platform dependent clean-up
499 pd_detachall();
500 }