1 /*
2 * Copyright (c) 2005, 2017, 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 "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 #include "services/writeableFlags.hpp"
41 #include "utilities/debug.hpp"
42 #include "utilities/formatBuffer.hpp"
43
44 volatile bool AttachListener::_initialized;
45
46 // Implementation of "properties" command.
47 //
48 // Invokes VMSupport.serializePropertiesToByteArray to serialize
49 // the system properties into a byte array.
50
51 static InstanceKlass* load_and_initialize_klass(Symbol* sh, TRAPS) {
52 Klass* k = SystemDictionary::resolve_or_fail(sh, true, CHECK_NULL);
53 InstanceKlass* ik = InstanceKlass::cast(k);
54 if (ik->should_be_initialized()) {
55 ik->initialize(CHECK_NULL);
56 }
57 return ik;
58 }
59
60 static jint get_properties(AttachOperation* op, outputStream* out, Symbol* serializePropertiesMethod) {
61 Thread* THREAD = Thread::current();
62 HandleMark hm;
63
64 // load VMSupport
65 Symbol* klass = vmSymbols::jdk_internal_vm_VMSupport();
66 InstanceKlass* k = load_and_initialize_klass(klass, THREAD);
67 if (HAS_PENDING_EXCEPTION) {
68 java_lang_Throwable::print(PENDING_EXCEPTION, out);
69 CLEAR_PENDING_EXCEPTION;
70 return JNI_ERR;
71 }
72
73 // invoke the serializePropertiesToByteArray method
74 JavaValue result(T_OBJECT);
75 JavaCallArguments args;
76
77
78 Symbol* signature = vmSymbols::serializePropertiesToByteArray_signature();
79 JavaCalls::call_static(&result,
80 k,
81 serializePropertiesMethod,
82 signature,
83 &args,
84 THREAD);
85 if (HAS_PENDING_EXCEPTION) {
86 java_lang_Throwable::print(PENDING_EXCEPTION, out);
87 CLEAR_PENDING_EXCEPTION;
88 return JNI_ERR;
89 }
90
91 // The result should be a [B
92 oop res = (oop)result.get_jobject();
93 assert(res->is_typeArray(), "just checking");
94 assert(TypeArrayKlass::cast(res->klass())->element_type() == T_BYTE, "just checking");
95
96 // copy the bytes to the output stream
97 typeArrayOop ba = typeArrayOop(res);
98 jbyte* addr = typeArrayOop(res)->byte_at_addr(0);
99 out->print_raw((const char*)addr, ba->length());
100
101 return JNI_OK;
102 }
103
104 // Implementation of "load" command.
105 static jint load_agent(AttachOperation* op, outputStream* out) {
106 // get agent name and options
107 const char* agent = op->arg(0);
108 const char* absParam = op->arg(1);
109 const char* options = op->arg(2);
110
111 // If loading a java agent then need to ensure that the java.instrument module is loaded
112 if (strcmp(agent, "instrument") == 0) {
113 Thread* THREAD = Thread::current();
114 ResourceMark rm(THREAD);
115 HandleMark hm(THREAD);
116 JavaValue result(T_OBJECT);
117 Handle h_module_name = java_lang_String::create_from_str("java.instrument", THREAD);
118 JavaCalls::call_static(&result,
119 SystemDictionary::module_Modules_klass(),
120 vmSymbols::loadModule_name(),
121 vmSymbols::loadModule_signature(),
122 h_module_name,
123 THREAD);
124 if (HAS_PENDING_EXCEPTION) {
125 java_lang_Throwable::print(PENDING_EXCEPTION, out);
126 CLEAR_PENDING_EXCEPTION;
127 return JNI_ERR;
128 }
129 }
130
131 return JvmtiExport::load_agent_library(agent, absParam, options, out);
132 }
133
134 // Implementation of "properties" command.
135 // See also: PrintSystemPropertiesDCmd class
136 static jint get_system_properties(AttachOperation* op, outputStream* out) {
137 return get_properties(op, out, vmSymbols::serializePropertiesToByteArray_name());
138 }
139
140 // Implementation of "agent_properties" command.
141 static jint get_agent_properties(AttachOperation* op, outputStream* out) {
142 return get_properties(op, out, vmSymbols::serializeAgentPropertiesToByteArray_name());
143 }
144
145 // Implementation of "datadump" command.
146 //
147 // Raises a SIGBREAK signal so that VM dump threads, does deadlock detection,
148 // etc. In theory this command should only post a DataDumpRequest to any
149 // JVMTI environment that has enabled this event. However it's useful to
150 // trigger the SIGBREAK handler.
151
152 static jint data_dump(AttachOperation* op, outputStream* out) {
153 if (!ReduceSignalUsage) {
154 AttachListener::pd_data_dump();
155 } else {
156 if (JvmtiExport::should_post_data_dump()) {
157 JvmtiExport::post_data_dump();
158 }
159 }
160 return JNI_OK;
161 }
162
163 // Implementation of "threaddump" command - essentially a remote ctrl-break
164 // See also: ThreadDumpDCmd class
165 //
166 static jint thread_dump(AttachOperation* op, outputStream* out) {
167 bool print_concurrent_locks = false;
168 if (op->arg(0) != NULL && strcmp(op->arg(0), "-l") == 0) {
169 print_concurrent_locks = true;
170 }
171
172 // thread stacks
173 VM_PrintThreads op1(out, print_concurrent_locks);
174 VMThread::execute(&op1);
175
176 // JNI global handles
177 VM_PrintJNI op2(out);
178 VMThread::execute(&op2);
179
180 // Deadlock detection
181 VM_FindDeadlocks op3(out);
182 VMThread::execute(&op3);
183
184 return JNI_OK;
185 }
186
187 // A jcmd attach operation request was received, which will now
188 // dispatch to the diagnostic commands used for serviceability functions.
189 static jint jcmd(AttachOperation* op, outputStream* out) {
190 Thread* THREAD = Thread::current();
191 // All the supplied jcmd arguments are stored as a single
192 // string (op->arg(0)). This is parsed by the Dcmd framework.
193 DCmd::parse_and_execute(DCmd_Source_AttachAPI, out, op->arg(0), ' ', THREAD);
194 if (HAS_PENDING_EXCEPTION) {
195 java_lang_Throwable::print(PENDING_EXCEPTION, out);
196 out->cr();
197 CLEAR_PENDING_EXCEPTION;
198 return JNI_ERR;
199 }
200 return JNI_OK;
201 }
202
203 // Implementation of "dumpheap" command.
204 // See also: HeapDumpDCmd class
205 //
206 // Input arguments :-
207 // arg0: Name of the dump file
208 // arg1: "-live" or "-all"
209 jint dump_heap(AttachOperation* op, outputStream* out) {
210 const char* path = op->arg(0);
211 if (path == NULL || path[0] == '\0') {
212 out->print_cr("No dump file specified");
213 } else {
214 bool live_objects_only = true; // default is true to retain the behavior before this change is made
215 const char* arg1 = op->arg(1);
216 if (arg1 != NULL && (strlen(arg1) > 0)) {
217 if (strcmp(arg1, "-all") != 0 && strcmp(arg1, "-live") != 0) {
218 out->print_cr("Invalid argument to dumpheap operation: %s", arg1);
219 return JNI_ERR;
220 }
221 live_objects_only = strcmp(arg1, "-live") == 0;
222 }
223
224 // Request a full GC before heap dump if live_objects_only = true
225 // This helps reduces the amount of unreachable objects in the dump
226 // and makes it easier to browse.
227 HeapDumper dumper(live_objects_only /* request GC */);
228 int res = dumper.dump(op->arg(0));
229 if (res == 0) {
230 out->print_cr("Heap dump file created");
231 } else {
232 // heap dump failed
233 ResourceMark rm;
234 char* error = dumper.error_as_C_string();
235 if (error == NULL) {
236 out->print_cr("Dump failed - reason unknown");
237 } else {
238 out->print_cr("%s", error);
239 }
240 }
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 static jint heap_inspection(AttachOperation* op, outputStream* out) {
251 bool live_objects_only = true; // default is true to retain the behavior before this change is made
252 const char* arg0 = op->arg(0);
253 if (arg0 != NULL && (strlen(arg0) > 0)) {
254 if (strcmp(arg0, "-all") != 0 && strcmp(arg0, "-live") != 0) {
255 out->print_cr("Invalid argument to inspectheap operation: %s", arg0);
256 return JNI_ERR;
257 }
258 live_objects_only = strcmp(arg0, "-live") == 0;
259 }
260 VM_GC_HeapInspection heapop(out, live_objects_only /* request full gc */);
261 VMThread::execute(&heapop);
262 return JNI_OK;
263 }
264
265 // Implementation of "setflag" command
266 static jint set_flag(AttachOperation* op, outputStream* out) {
267
268 const char* name = NULL;
269 if ((name = op->arg(0)) == NULL) {
270 out->print_cr("flag name is missing");
271 return JNI_ERR;
272 }
273
274 FormatBuffer<80> err_msg("%s", "");
275
276 int ret = WriteableFlags::set_flag(op->arg(0), op->arg(1), Flag::ATTACH_ON_DEMAND, err_msg);
277 if (ret != Flag::SUCCESS) {
278 if (ret == Flag::NON_WRITABLE) {
279 // if the flag is not manageable try to change it through
280 // the platform dependent implementation
281 return AttachListener::pd_set_flag(op, out);
282 } else {
283 out->print_cr("%s", err_msg.buffer());
284 }
285
286 return JNI_ERR;
287 }
288 return JNI_OK;
289 }
290
291 // Implementation of "printflag" command
292 // See also: PrintVMFlagsDCmd class
293 static jint print_flag(AttachOperation* op, outputStream* out) {
294 const char* name = NULL;
295 if ((name = op->arg(0)) == NULL) {
296 out->print_cr("flag name is missing");
297 return JNI_ERR;
298 }
299 Flag* f = Flag::find_flag((char*)name, strlen(name));
300 if (f) {
301 f->print_as_flag(out);
302 out->cr();
303 } else {
304 out->print_cr("no such flag '%s'", name);
305 }
306 return JNI_OK;
307 }
308
309 // Table to map operation names to functions.
310
311 // names must be of length <= AttachOperation::name_length_max
312 static AttachOperationFunctionInfo funcs[] = {
313 { "agentProperties", get_agent_properties },
314 { "datadump", data_dump },
315 { "dumpheap", dump_heap },
316 { "load", load_agent },
317 { "properties", get_system_properties },
318 { "threaddump", thread_dump },
319 { "inspectheap", heap_inspection },
320 { "setflag", set_flag },
321 { "printflag", print_flag },
322 { "jcmd", jcmd },
323 { NULL, NULL }
324 };
325
326
327
328 // The Attach Listener threads services a queue. It dequeues an operation
329 // from the queue, examines the operation name (command), and dispatches
330 // to the corresponding function to perform the operation.
331
332 static void attach_listener_thread_entry(JavaThread* thread, TRAPS) {
333 os::set_priority(thread, NearMaxPriority);
334
335 thread->record_stack_base_and_size();
336
337 if (AttachListener::pd_init() != 0) {
338 return;
339 }
340 AttachListener::set_initialized();
341
342 for (;;) {
343 AttachOperation* op = AttachListener::dequeue();
344 if (op == NULL) {
345 return; // dequeue failed or shutdown
346 }
347
348 ResourceMark rm;
349 bufferedStream st;
350 jint res = JNI_OK;
351
352 // handle special detachall operation
353 if (strcmp(op->name(), AttachOperation::detachall_operation_name()) == 0) {
354 AttachListener::detachall();
355 } else if (!EnableDynamicAgentLoading && strcmp(op->name(), "load") == 0) {
356 st.print("Dynamic agent loading is not enabled. "
357 "Use -XX:+EnableDynamicAgentLoading to launch target VM.");
358 res = JNI_ERR;
359 } else {
360 // find the function to dispatch too
361 AttachOperationFunctionInfo* info = NULL;
362 for (int i=0; funcs[i].name != NULL; i++) {
363 const char* name = funcs[i].name;
364 assert(strlen(name) <= AttachOperation::name_length_max, "operation <= name_length_max");
365 if (strcmp(op->name(), name) == 0) {
366 info = &(funcs[i]);
367 break;
368 }
369 }
370
371 // check for platform dependent attach operation
372 if (info == NULL) {
373 info = AttachListener::pd_find_operation(op->name());
374 }
375
376 if (info != NULL) {
377 // dispatch to the function that implements this operation
378 res = (info->func)(op, &st);
379 } else {
380 st.print("Operation %s not recognized!", op->name());
381 res = JNI_ERR;
382 }
383 }
384
385 // operation complete - send result and output to client
386 op->complete(res, &st);
387 }
388 }
389
390 bool AttachListener::has_init_error(TRAPS) {
391 if (HAS_PENDING_EXCEPTION) {
392 tty->print_cr("Exception in VM (AttachListener::init) : ");
393 java_lang_Throwable::print(PENDING_EXCEPTION, tty);
394 tty->cr();
395
396 CLEAR_PENDING_EXCEPTION;
397
398 return true;
399 } else {
400 return false;
401 }
402 }
403
404 // Starts the Attach Listener thread
405 void AttachListener::init() {
406 EXCEPTION_MARK;
407 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, THREAD);
408 if (has_init_error(THREAD)) {
409 return;
410 }
411
412 InstanceKlass* klass = InstanceKlass::cast(k);
413 instanceHandle thread_oop = klass->allocate_instance_handle(THREAD);
414 if (has_init_error(THREAD)) {
415 return;
416 }
417
418 const char thread_name[] = "Attach Listener";
419 Handle string = java_lang_String::create_from_str(thread_name, THREAD);
420 if (has_init_error(THREAD)) {
421 return;
422 }
423
424 // Initialize thread_oop to put it into the system threadGroup
425 Handle thread_group (THREAD, Universe::system_thread_group());
426 JavaValue result(T_VOID);
427 JavaCalls::call_special(&result, thread_oop,
428 klass,
429 vmSymbols::object_initializer_name(),
430 vmSymbols::threadgroup_string_void_signature(),
431 thread_group,
432 string,
433 THREAD);
434
435 if (has_init_error(THREAD)) {
436 return;
437 }
438
439 Klass* group = SystemDictionary::ThreadGroup_klass();
440 JavaCalls::call_special(&result,
441 thread_group,
442 group,
443 vmSymbols::add_method_name(),
444 vmSymbols::thread_void_signature(),
445 thread_oop, // ARG 1
446 THREAD);
447 if (has_init_error(THREAD)) {
448 return;
449 }
450
451 { MutexLocker mu(Threads_lock);
452 JavaThread* listener_thread = new JavaThread(&attach_listener_thread_entry);
453
454 // Check that thread and osthread were created
455 if (listener_thread == NULL || listener_thread->osthread() == NULL) {
456 vm_exit_during_initialization("java.lang.OutOfMemoryError",
457 os::native_thread_creation_failed_msg());
458 }
459
460 java_lang_Thread::set_thread(thread_oop(), listener_thread);
461 java_lang_Thread::set_daemon(thread_oop());
462
463 listener_thread->set_threadObj(thread_oop());
464 Threads::add(listener_thread);
465 Thread::start(listener_thread);
466 }
467 }
468
469 // Performs clean-up tasks on platforms where we can detect that the last
470 // client has detached
471 void AttachListener::detachall() {
472 // call the platform dependent clean-up
473 pd_detachall();
474 }