1 /*
2 * Copyright (c) 2005, 2018, 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/vmGCOperations.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "oops/oop.inline.hpp"
31 #include "oops/typeArrayOop.inline.hpp"
32 #include "prims/jvmtiExport.hpp"
33 #include "runtime/arguments.hpp"
34 #include "runtime/globals.hpp"
35 #include "runtime/java.hpp"
36 #include "runtime/javaCalls.hpp"
37 #include "runtime/os.hpp"
38 #include "services/attachListener.hpp"
39 #include "services/diagnosticCommand.hpp"
40 #include "services/heapDumper.hpp"
41 #include "services/writeableFlags.hpp"
42 #include "utilities/debug.hpp"
43 #include "utilities/formatBuffer.hpp"
44
45 volatile bool AttachListener::_initialized;
46
47 // Implementation of "properties" command.
48 //
49 // Invokes VMSupport.serializePropertiesToByteArray to serialize
50 // the system properties into a byte array.
51
52 static InstanceKlass* load_and_initialize_klass(Symbol* sh, TRAPS) {
53 Klass* k = SystemDictionary::resolve_or_fail(sh, true, CHECK_NULL);
54 InstanceKlass* ik = InstanceKlass::cast(k);
55 if (ik->should_be_initialized()) {
56 ik->initialize(CHECK_NULL);
57 }
58 return ik;
59 }
60
61 static jint get_properties(AttachOperation* op, outputStream* out, Symbol* serializePropertiesMethod) {
62 Thread* THREAD = Thread::current();
63 HandleMark hm;
64
65 // load VMSupport
66 Symbol* klass = vmSymbols::jdk_internal_vm_VMSupport();
67 InstanceKlass* k = load_and_initialize_klass(klass, THREAD);
68 if (HAS_PENDING_EXCEPTION) {
69 java_lang_Throwable::print(PENDING_EXCEPTION, out);
70 CLEAR_PENDING_EXCEPTION;
71 return JNI_ERR;
72 }
73
74 // invoke the serializePropertiesToByteArray method
75 JavaValue result(T_OBJECT);
76 JavaCallArguments args;
77
78
79 Symbol* signature = vmSymbols::serializePropertiesToByteArray_signature();
80 JavaCalls::call_static(&result,
81 k,
82 serializePropertiesMethod,
83 signature,
84 &args,
85 THREAD);
86 if (HAS_PENDING_EXCEPTION) {
87 java_lang_Throwable::print(PENDING_EXCEPTION, out);
88 CLEAR_PENDING_EXCEPTION;
89 return JNI_ERR;
90 }
91
92 // The result should be a [B
93 oop res = (oop)result.get_jobject();
94 assert(res->is_typeArray(), "just checking");
95 assert(TypeArrayKlass::cast(res->klass())->element_type() == T_BYTE, "just checking");
96
97 // copy the bytes to the output stream
98 typeArrayOop ba = typeArrayOop(res);
99 jbyte* addr = typeArrayOop(res)->byte_at_addr(0);
100 out->print_raw((const char*)addr, ba->length());
101
102 return JNI_OK;
103 }
104
105 // Implementation of "load" command.
106 static jint load_agent(AttachOperation* op, outputStream* out) {
107 // get agent name and options
108 const char* agent = op->arg(0);
109 const char* absParam = op->arg(1);
110 const char* options = op->arg(2);
111
112 // If loading a java agent then need to ensure that the java.instrument module is loaded
113 if (strcmp(agent, "instrument") == 0) {
114 Thread* THREAD = Thread::current();
115 ResourceMark rm(THREAD);
116 HandleMark hm(THREAD);
117 JavaValue result(T_OBJECT);
118 Handle h_module_name = java_lang_String::create_from_str("java.instrument", THREAD);
119 JavaCalls::call_static(&result,
120 SystemDictionary::module_Modules_klass(),
121 vmSymbols::loadModule_name(),
122 vmSymbols::loadModule_signature(),
123 h_module_name,
124 THREAD);
125 if (HAS_PENDING_EXCEPTION) {
126 java_lang_Throwable::print(PENDING_EXCEPTION, out);
127 CLEAR_PENDING_EXCEPTION;
128 return JNI_ERR;
129 }
130 }
131
132 return JvmtiExport::load_agent_library(agent, absParam, options, out);
133 }
134
135 // Implementation of "properties" command.
136 // See also: PrintSystemPropertiesDCmd class
137 static jint get_system_properties(AttachOperation* op, outputStream* out) {
138 return get_properties(op, out, vmSymbols::serializePropertiesToByteArray_name());
139 }
140
141 // Implementation of "agent_properties" command.
142 static jint get_agent_properties(AttachOperation* op, outputStream* out) {
143 return get_properties(op, out, vmSymbols::serializeAgentPropertiesToByteArray_name());
144 }
145
146 // Implementation of "datadump" command.
147 //
148 // Raises a SIGBREAK signal so that VM dump threads, does deadlock detection,
149 // etc. In theory this command should only post a DataDumpRequest to any
150 // JVMTI environment that has enabled this event. However it's useful to
151 // trigger the SIGBREAK handler.
152
153 static jint data_dump(AttachOperation* op, outputStream* out) {
154 if (!ReduceSignalUsage) {
155 AttachListener::pd_data_dump();
156 } else {
157 if (JvmtiExport::should_post_data_dump()) {
158 JvmtiExport::post_data_dump();
159 }
160 }
161 return JNI_OK;
162 }
163
164 // Implementation of "threaddump" command - essentially a remote ctrl-break
165 // See also: ThreadDumpDCmd class
166 //
167 static jint thread_dump(AttachOperation* op, outputStream* out) {
168 bool print_concurrent_locks = false;
169 if (op->arg(0) != NULL && strcmp(op->arg(0), "-l") == 0) {
170 print_concurrent_locks = true;
171 }
172
173 // thread stacks
174 VM_PrintThreads op1(out, print_concurrent_locks);
175 VMThread::execute(&op1);
176
177 // JNI global handles
178 VM_PrintJNI op2(out);
179 VMThread::execute(&op2);
180
181 // Deadlock detection
182 VM_FindDeadlocks op3(out);
183 VMThread::execute(&op3);
184
185 return JNI_OK;
186 }
187
188 // A jcmd attach operation request was received, which will now
189 // dispatch to the diagnostic commands used for serviceability functions.
190 static jint jcmd(AttachOperation* op, outputStream* out) {
191 Thread* THREAD = Thread::current();
192 // All the supplied jcmd arguments are stored as a single
193 // string (op->arg(0)). This is parsed by the Dcmd framework.
194 DCmd::parse_and_execute(DCmd_Source_AttachAPI, out, op->arg(0), ' ', THREAD);
195 if (HAS_PENDING_EXCEPTION) {
196 java_lang_Throwable::print(PENDING_EXCEPTION, out);
197 out->cr();
198 CLEAR_PENDING_EXCEPTION;
199 return JNI_ERR;
200 }
201 return JNI_OK;
202 }
203
204 // Implementation of "dumpheap" command.
205 // See also: HeapDumpDCmd class
206 //
207 // Input arguments :-
208 // arg0: Name of the dump file
209 // arg1: "-live" or "-all"
210 jint dump_heap(AttachOperation* op, outputStream* out) {
211 const char* path = op->arg(0);
212 if (path == NULL || path[0] == '\0') {
213 out->print_cr("No dump file specified");
214 } else {
215 bool live_objects_only = true; // default is true to retain the behavior before this change is made
216 const char* arg1 = op->arg(1);
217 if (arg1 != NULL && (strlen(arg1) > 0)) {
218 if (strcmp(arg1, "-all") != 0 && strcmp(arg1, "-live") != 0) {
219 out->print_cr("Invalid argument to dumpheap operation: %s", arg1);
220 return JNI_ERR;
221 }
222 live_objects_only = strcmp(arg1, "-live") == 0;
223 }
224
225 // Request a full GC before heap dump if live_objects_only = true
226 // This helps reduces the amount of unreachable objects in the dump
227 // and makes it easier to browse.
228 HeapDumper dumper(live_objects_only /* request GC */);
229 int res = dumper.dump(op->arg(0));
230 if (res == 0) {
231 out->print_cr("Heap dump file created");
232 } else {
233 // heap dump failed
234 ResourceMark rm;
235 char* error = dumper.error_as_C_string();
236 if (error == NULL) {
237 out->print_cr("Dump failed - reason unknown");
238 } else {
239 out->print_cr("%s", error);
240 }
241 }
242 }
243 return JNI_OK;
244 }
245
246 // Implementation of "inspectheap" command
247 // See also: ClassHistogramDCmd class
248 //
249 // Input arguments :-
250 // arg0: "-live" or "-all"
251 static jint heap_inspection(AttachOperation* op, outputStream* out) {
252 bool live_objects_only = true; // default is true to retain the behavior before this change is made
253 const char* arg0 = op->arg(0);
254 if (arg0 != NULL && (strlen(arg0) > 0)) {
255 if (strcmp(arg0, "-all") != 0 && strcmp(arg0, "-live") != 0) {
256 out->print_cr("Invalid argument to inspectheap operation: %s", arg0);
257 return JNI_ERR;
258 }
259 live_objects_only = strcmp(arg0, "-live") == 0;
260 }
261 VM_GC_HeapInspection heapop(out, live_objects_only /* request full gc */);
262 VMThread::execute(&heapop);
263 return JNI_OK;
264 }
265
266 // Implementation of "setflag" command
267 static jint set_flag(AttachOperation* op, outputStream* out) {
268
269 const char* name = NULL;
270 if ((name = op->arg(0)) == NULL) {
271 out->print_cr("flag name is missing");
272 return JNI_ERR;
273 }
274
275 FormatBuffer<80> err_msg("%s", "");
276
277 int ret = WriteableFlags::set_flag(op->arg(0), op->arg(1), Flag::ATTACH_ON_DEMAND, err_msg);
278 if (ret != Flag::SUCCESS) {
279 if (ret == Flag::NON_WRITABLE) {
280 // if the flag is not manageable try to change it through
281 // the platform dependent implementation
282 return AttachListener::pd_set_flag(op, out);
283 } else {
284 out->print_cr("%s", err_msg.buffer());
285 }
286
287 return JNI_ERR;
288 }
289 return JNI_OK;
290 }
291
292 // Implementation of "printflag" command
293 // See also: PrintVMFlagsDCmd class
294 static jint print_flag(AttachOperation* op, outputStream* out) {
295 const char* name = NULL;
296 if ((name = op->arg(0)) == NULL) {
297 out->print_cr("flag name is missing");
298 return JNI_ERR;
299 }
300 Flag* f = Flag::find_flag((char*)name, strlen(name));
301 if (f) {
302 f->print_as_flag(out);
303 out->cr();
304 } else {
305 out->print_cr("no such flag '%s'", name);
306 }
307 return JNI_OK;
308 }
309
310 // Table to map operation names to functions.
311
312 // names must be of length <= AttachOperation::name_length_max
313 static AttachOperationFunctionInfo funcs[] = {
314 { "agentProperties", get_agent_properties },
315 { "datadump", data_dump },
316 { "dumpheap", dump_heap },
317 { "load", load_agent },
318 { "properties", get_system_properties },
319 { "threaddump", thread_dump },
320 { "inspectheap", heap_inspection },
321 { "setflag", set_flag },
322 { "printflag", print_flag },
323 { "jcmd", jcmd },
324 { NULL, NULL }
325 };
326
327
328
329 // The Attach Listener threads services a queue. It dequeues an operation
330 // from the queue, examines the operation name (command), and dispatches
331 // to the corresponding function to perform the operation.
332
333 static void attach_listener_thread_entry(JavaThread* thread, TRAPS) {
334 os::set_priority(thread, NearMaxPriority);
335
336 thread->record_stack_base_and_size();
337
338 if (AttachListener::pd_init() != 0) {
339 return;
340 }
341 AttachListener::set_initialized();
342
343 for (;;) {
344 AttachOperation* op = AttachListener::dequeue();
345 if (op == NULL) {
346 return; // dequeue failed or shutdown
347 }
348
349 ResourceMark rm;
350 bufferedStream st;
351 jint res = JNI_OK;
352
353 // handle special detachall operation
354 if (strcmp(op->name(), AttachOperation::detachall_operation_name()) == 0) {
355 AttachListener::detachall();
356 } else if (!EnableDynamicAgentLoading && strcmp(op->name(), "load") == 0) {
357 st.print("Dynamic agent loading is not enabled. "
358 "Use -XX:+EnableDynamicAgentLoading to launch target VM.");
359 res = JNI_ERR;
360 } else {
361 // find the function to dispatch too
362 AttachOperationFunctionInfo* info = NULL;
363 for (int i=0; funcs[i].name != NULL; i++) {
364 const char* name = funcs[i].name;
365 assert(strlen(name) <= AttachOperation::name_length_max, "operation <= name_length_max");
366 if (strcmp(op->name(), name) == 0) {
367 info = &(funcs[i]);
368 break;
369 }
370 }
371
372 // check for platform dependent attach operation
373 if (info == NULL) {
374 info = AttachListener::pd_find_operation(op->name());
375 }
376
377 if (info != NULL) {
378 // dispatch to the function that implements this operation
379 res = (info->func)(op, &st);
380 } else {
381 st.print("Operation %s not recognized!", op->name());
382 res = JNI_ERR;
383 }
384 }
385
386 // operation complete - send result and output to client
387 op->complete(res, &st);
388 }
389 }
390
391 bool AttachListener::has_init_error(TRAPS) {
392 if (HAS_PENDING_EXCEPTION) {
393 tty->print_cr("Exception in VM (AttachListener::init) : ");
394 java_lang_Throwable::print(PENDING_EXCEPTION, tty);
395 tty->cr();
396
397 CLEAR_PENDING_EXCEPTION;
398
399 return true;
400 } else {
401 return false;
402 }
403 }
404
405 // Starts the Attach Listener thread
406 void AttachListener::init() {
407 EXCEPTION_MARK;
408 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, THREAD);
409 if (has_init_error(THREAD)) {
410 return;
411 }
412
413 InstanceKlass* klass = InstanceKlass::cast(k);
414 instanceHandle thread_oop = klass->allocate_instance_handle(THREAD);
415 if (has_init_error(THREAD)) {
416 return;
417 }
418
419 const char thread_name[] = "Attach Listener";
420 Handle string = java_lang_String::create_from_str(thread_name, THREAD);
421 if (has_init_error(THREAD)) {
422 return;
423 }
424
425 // Initialize thread_oop to put it into the system threadGroup
426 Handle thread_group (THREAD, Universe::system_thread_group());
427 JavaValue result(T_VOID);
428 JavaCalls::call_special(&result, thread_oop,
429 klass,
430 vmSymbols::object_initializer_name(),
431 vmSymbols::threadgroup_string_void_signature(),
432 thread_group,
433 string,
434 THREAD);
435
436 if (has_init_error(THREAD)) {
437 return;
438 }
439
440 Klass* group = SystemDictionary::ThreadGroup_klass();
441 JavaCalls::call_special(&result,
442 thread_group,
443 group,
444 vmSymbols::add_method_name(),
445 vmSymbols::thread_void_signature(),
446 thread_oop, // ARG 1
447 THREAD);
448 if (has_init_error(THREAD)) {
449 return;
450 }
451
452 { MutexLocker mu(Threads_lock);
453 JavaThread* listener_thread = new JavaThread(&attach_listener_thread_entry);
454
455 // Check that thread and osthread were created
456 if (listener_thread == NULL || listener_thread->osthread() == NULL) {
457 vm_exit_during_initialization("java.lang.OutOfMemoryError",
458 os::native_thread_creation_failed_msg());
459 }
460
461 java_lang_Thread::set_thread(thread_oop(), listener_thread);
462 java_lang_Thread::set_daemon(thread_oop());
463
464 listener_thread->set_threadObj(thread_oop());
465 Threads::add(listener_thread);
466 Thread::start(listener_thread);
467 }
468 }
469
470 // Performs clean-up tasks on platforms where we can detect that the last
471 // client has detached
472 void AttachListener::detachall() {
473 // call the platform dependent clean-up
474 pd_detachall();
475 }