1 /*
2 * Copyright (c) 2005, 2015, 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 sun.misc.VMSupport.serializePropertiesToByteArray to serialize
47 // the system properties into a byte array.
48
49 static Klass* load_and_initialize_klass(Symbol* sh, TRAPS) {
50 Klass* k = SystemDictionary::resolve_or_fail(sh, true, CHECK_NULL);
51 instanceKlassHandle ik (THREAD, 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 sun.misc.VMSupport
63 Symbol* klass = vmSymbols::sun_misc_VMSupport();
64 Klass* 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 instanceKlassHandle ik(THREAD, k);
71
72 // invoke the serializePropertiesToByteArray method
73 JavaValue result(T_OBJECT);
74 JavaCallArguments args;
75
76
77 Symbol* signature = vmSymbols::serializePropertiesToByteArray_signature();
78 JavaCalls::call_static(&result,
79 ik,
80 serializePropertiesMethod,
81 signature,
82 &args,
83 THREAD);
84 if (HAS_PENDING_EXCEPTION) {
85 java_lang_Throwable::print(PENDING_EXCEPTION, out);
86 CLEAR_PENDING_EXCEPTION;
87 return JNI_ERR;
88 }
89
90 // The result should be a [B
91 oop res = (oop)result.get_jobject();
92 assert(res->is_typeArray(), "just checking");
93 assert(TypeArrayKlass::cast(res->klass())->element_type() == T_BYTE, "just checking");
94
95 // copy the bytes to the output stream
96 typeArrayOop ba = typeArrayOop(res);
97 jbyte* addr = typeArrayOop(res)->byte_at_addr(0);
98 out->print_raw((const char*)addr, ba->length());
99
100 return JNI_OK;
101 }
102
103 // Implementation of "properties" command.
104 // See also: PrintSystemPropertiesDCmd class
105 static jint get_system_properties(AttachOperation* op, outputStream* out) {
106 return get_properties(op, out, vmSymbols::serializePropertiesToByteArray_name());
107 }
108
109 // Implementation of "agent_properties" command.
110 static jint get_agent_properties(AttachOperation* op, outputStream* out) {
111 return get_properties(op, out, vmSymbols::serializeAgentPropertiesToByteArray_name());
112 }
113
114 // Implementation of "datadump" command.
115 //
116 // Raises a SIGBREAK signal so that VM dump threads, does deadlock detection,
117 // etc. In theory this command should only post a DataDumpRequest to any
118 // JVMTI environment that has enabled this event. However it's useful to
119 // trigger the SIGBREAK handler.
120
121 static jint data_dump(AttachOperation* op, outputStream* out) {
122 if (!ReduceSignalUsage) {
123 AttachListener::pd_data_dump();
124 } else {
125 if (JvmtiExport::should_post_data_dump()) {
126 JvmtiExport::post_data_dump();
127 }
128 }
129 return JNI_OK;
130 }
131
132 // Implementation of "threaddump" command - essentially a remote ctrl-break
133 // See also: ThreadDumpDCmd class
134 //
135 static jint thread_dump(AttachOperation* op, outputStream* out) {
136 bool print_concurrent_locks = false;
137 if (op->arg(0) != NULL && strcmp(op->arg(0), "-l") == 0) {
138 print_concurrent_locks = true;
139 }
140
141 // thread stacks
142 VM_PrintThreads op1(out, print_concurrent_locks);
143 VMThread::execute(&op1);
144
145 // JNI global handles
146 VM_PrintJNI op2(out);
147 VMThread::execute(&op2);
148
149 // Deadlock detection
150 VM_FindDeadlocks op3(out);
151 VMThread::execute(&op3);
152
153 return JNI_OK;
154 }
155
156 // A jcmd attach operation request was received, which will now
157 // dispatch to the diagnostic commands used for serviceability functions.
158 static jint jcmd(AttachOperation* op, outputStream* out) {
159 Thread* THREAD = Thread::current();
160 // All the supplied jcmd arguments are stored as a single
161 // string (op->arg(0)). This is parsed by the Dcmd framework.
162 DCmd::parse_and_execute(DCmd_Source_AttachAPI, out, op->arg(0), ' ', THREAD);
163 if (HAS_PENDING_EXCEPTION) {
164 java_lang_Throwable::print(PENDING_EXCEPTION, out);
165 out->cr();
166 CLEAR_PENDING_EXCEPTION;
167 return JNI_ERR;
168 }
169 return JNI_OK;
170 }
171
172 // Implementation of "dumpheap" command.
173 // See also: HeapDumpDCmd class
174 //
175 // Input arguments :-
176 // arg0: Name of the dump file
177 // arg1: "-live" or "-all"
178 jint dump_heap(AttachOperation* op, outputStream* out) {
179 const char* path = op->arg(0);
180 if (path == NULL || path[0] == '\0') {
181 out->print_cr("No dump file specified");
182 } else {
183 bool live_objects_only = true; // default is true to retain the behavior before this change is made
184 const char* arg1 = op->arg(1);
185 if (arg1 != NULL && (strlen(arg1) > 0)) {
186 if (strcmp(arg1, "-all") != 0 && strcmp(arg1, "-live") != 0) {
187 out->print_cr("Invalid argument to dumpheap operation: %s", arg1);
188 return JNI_ERR;
189 }
190 live_objects_only = strcmp(arg1, "-live") == 0;
191 }
192
193 // Request a full GC before heap dump if live_objects_only = true
194 // This helps reduces the amount of unreachable objects in the dump
195 // and makes it easier to browse.
196 HeapDumper dumper(live_objects_only /* request GC */);
197 int res = dumper.dump(op->arg(0));
198 if (res == 0) {
199 out->print_cr("Heap dump file created");
200 } else {
201 // heap dump failed
202 ResourceMark rm;
203 char* error = dumper.error_as_C_string();
204 if (error == NULL) {
205 out->print_cr("Dump failed - reason unknown");
206 } else {
207 out->print_cr("%s", error);
208 }
209 }
210 }
211 return JNI_OK;
212 }
213
214 // Implementation of "inspectheap" command
215 // See also: ClassHistogramDCmd class
216 //
217 // Input arguments :-
218 // arg0: "-live" or "-all"
219 static jint heap_inspection(AttachOperation* op, outputStream* out) {
220 bool live_objects_only = true; // default is true to retain the behavior before this change is made
221 const char* arg0 = op->arg(0);
222 if (arg0 != NULL && (strlen(arg0) > 0)) {
223 if (strcmp(arg0, "-all") != 0 && strcmp(arg0, "-live") != 0) {
224 out->print_cr("Invalid argument to inspectheap operation: %s", arg0);
225 return JNI_ERR;
226 }
227 live_objects_only = strcmp(arg0, "-live") == 0;
228 }
229 VM_GC_HeapInspection heapop(out, live_objects_only /* request full gc */);
230 VMThread::execute(&heapop);
231 return JNI_OK;
232 }
233
234 // Implementation of "setflag" command
235 static jint set_flag(AttachOperation* op, outputStream* out) {
236
237 const char* name = NULL;
238 if ((name = op->arg(0)) == NULL) {
239 out->print_cr("flag name is missing");
240 return JNI_ERR;
241 }
242
243 FormatBuffer<80> err_msg("%s", "");
244
245 int ret = WriteableFlags::set_flag(op->arg(0), op->arg(1), Flag::ATTACH_ON_DEMAND, err_msg);
246 if (ret != Flag::SUCCESS) {
247 if (ret == Flag::NON_WRITABLE) {
248 // if the flag is not manageable try to change it through
249 // the platform dependent implementation
250 return AttachListener::pd_set_flag(op, out);
251 } else {
252 out->print_cr("%s", err_msg.buffer());
253 }
254
255 return JNI_ERR;
256 }
257 return JNI_OK;
258 }
259
260 // Implementation of "printflag" command
261 // See also: PrintVMFlagsDCmd class
262 static jint print_flag(AttachOperation* op, outputStream* out) {
263 const char* name = NULL;
264 if ((name = op->arg(0)) == NULL) {
265 out->print_cr("flag name is missing");
266 return JNI_ERR;
267 }
268 Flag* f = Flag::find_flag((char*)name, strlen(name));
269 if (f) {
270 f->print_as_flag(out);
271 out->cr();
272 } else {
273 out->print_cr("no such flag '%s'", name);
274 }
275 return JNI_OK;
276 }
277
278 // Table to map operation names to functions.
279
280 // names must be of length <= AttachOperation::name_length_max
281 static AttachOperationFunctionInfo funcs[] = {
282 { "agentProperties", get_agent_properties },
283 { "datadump", data_dump },
284 { "dumpheap", dump_heap },
285 { "load", JvmtiExport::load_agent_library },
286 { "properties", get_system_properties },
287 { "threaddump", thread_dump },
288 { "inspectheap", heap_inspection },
289 { "setflag", set_flag },
290 { "printflag", print_flag },
291 { "jcmd", jcmd },
292 { NULL, NULL }
293 };
294
295
296
297 // The Attach Listener threads services a queue. It dequeues an operation
298 // from the queue, examines the operation name (command), and dispatches
299 // to the corresponding function to perform the operation.
300
301 static void attach_listener_thread_entry(JavaThread* thread, TRAPS) {
302 os::set_priority(thread, NearMaxPriority);
303
304 thread->record_stack_base_and_size();
305
306 if (AttachListener::pd_init() != 0) {
307 return;
308 }
309 AttachListener::set_initialized();
310
311 for (;;) {
312 AttachOperation* op = AttachListener::dequeue();
313 if (op == NULL) {
314 return; // dequeue failed or shutdown
315 }
316
317 ResourceMark rm;
318 bufferedStream st;
319 jint res = JNI_OK;
320
321 // handle special detachall operation
322 if (strcmp(op->name(), AttachOperation::detachall_operation_name()) == 0) {
323 AttachListener::detachall();
324 } else {
325 // find the function to dispatch too
326 AttachOperationFunctionInfo* info = NULL;
327 for (int i=0; funcs[i].name != NULL; i++) {
328 const char* name = funcs[i].name;
329 assert(strlen(name) <= AttachOperation::name_length_max, "operation <= name_length_max");
330 if (strcmp(op->name(), name) == 0) {
331 info = &(funcs[i]);
332 break;
333 }
334 }
335
336 // check for platform dependent attach operation
337 if (info == NULL) {
338 info = AttachListener::pd_find_operation(op->name());
339 }
340
341 if (info != NULL) {
342 // dispatch to the function that implements this operation
343 res = (info->func)(op, &st);
344 } else {
345 st.print("Operation %s not recognized!", op->name());
346 res = JNI_ERR;
347 }
348 }
349
350 // operation complete - send result and output to client
351 op->complete(res, &st);
352 }
353 }
354
355 bool AttachListener::has_init_error(TRAPS) {
356 if (HAS_PENDING_EXCEPTION) {
357 tty->print_cr("Exception in VM (AttachListener::init) : ");
358 java_lang_Throwable::print(PENDING_EXCEPTION, tty);
359 tty->cr();
360
361 CLEAR_PENDING_EXCEPTION;
362
363 return true;
364 } else {
365 return false;
366 }
367 }
368
369 // Starts the Attach Listener thread
370 void AttachListener::init() {
371 EXCEPTION_MARK;
372 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, THREAD);
373 if (has_init_error(THREAD)) {
374 return;
375 }
376
377 instanceKlassHandle klass (THREAD, k);
378 instanceHandle thread_oop = klass->allocate_instance_handle(THREAD);
379 if (has_init_error(THREAD)) {
380 return;
381 }
382
383 const char thread_name[] = "Attach Listener";
384 Handle string = java_lang_String::create_from_str(thread_name, THREAD);
385 if (has_init_error(THREAD)) {
386 return;
387 }
388
389 // Initialize thread_oop to put it into the system threadGroup
390 Handle thread_group (THREAD, Universe::system_thread_group());
391 JavaValue result(T_VOID);
392 JavaCalls::call_special(&result, thread_oop,
393 klass,
394 vmSymbols::object_initializer_name(),
395 vmSymbols::threadgroup_string_void_signature(),
396 thread_group,
397 string,
398 THREAD);
399
400 if (has_init_error(THREAD)) {
401 return;
402 }
403
404 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
405 JavaCalls::call_special(&result,
406 thread_group,
407 group,
408 vmSymbols::add_method_name(),
409 vmSymbols::thread_void_signature(),
410 thread_oop, // ARG 1
411 THREAD);
412 if (has_init_error(THREAD)) {
413 return;
414 }
415
416 { MutexLocker mu(Threads_lock);
417 JavaThread* listener_thread = new JavaThread(&attach_listener_thread_entry);
418
419 // Check that thread and osthread were created
420 if (listener_thread == NULL || listener_thread->osthread() == NULL) {
421 vm_exit_during_initialization("java.lang.OutOfMemoryError",
422 os::native_thread_creation_failed_msg());
423 }
424
425 java_lang_Thread::set_thread(thread_oop(), listener_thread);
426 java_lang_Thread::set_daemon(thread_oop());
427
428 listener_thread->set_threadObj(thread_oop());
429 Threads::add(listener_thread);
430 Thread::start(listener_thread);
431 }
432 }
433
434 // Performs clean-up tasks on platforms where we can detect that the last
435 // client has detached
436 void AttachListener::detachall() {
437 // call the platform dependent clean-up
438 pd_detachall();
439 }