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