1 /*
2 * Copyright (c) 2005, 2013, 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_implementation/shared/vmGCOperations.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "prims/jvmtiExport.hpp"
31 #include "runtime/arguments.hpp"
32 #include "runtime/globals.hpp"
33 #include "runtime/java.hpp"
34 #include "runtime/javaCalls.hpp"
35 #include "runtime/os.hpp"
36 #include "services/attachListener.hpp"
37 #include "services/diagnosticCommand.hpp"
38 #include "services/heapDumper.hpp"
39
40 volatile bool AttachListener::_initialized;
41
42 // Implementation of "properties" command.
43 //
44 // Invokes sun.misc.VMSupport.serializePropertiesToByteArray to serialize
45 // the system properties into a byte array.
46
47 static Klass* load_and_initialize_klass(Symbol* sh, TRAPS) {
48 Klass* k = SystemDictionary::resolve_or_fail(sh, true, CHECK_NULL);
49 instanceKlassHandle ik (THREAD, k);
50 if (ik->should_be_initialized()) {
51 ik->initialize(CHECK_NULL);
52 }
53 return ik();
54 }
55
56 static jint get_properties(AttachOperation* op, outputStream* out, Symbol* serializePropertiesMethod) {
57 Thread* THREAD = Thread::current();
58 HandleMark hm;
59
60 // load sun.misc.VMSupport
61 Symbol* klass = vmSymbols::sun_misc_VMSupport();
62 Klass* k = load_and_initialize_klass(klass, THREAD);
63 if (HAS_PENDING_EXCEPTION) {
64 java_lang_Throwable::print(PENDING_EXCEPTION, out);
65 CLEAR_PENDING_EXCEPTION;
66 return JNI_ERR;
67 }
68 instanceKlassHandle ik(THREAD, k);
69
70 // invoke the serializePropertiesToByteArray method
71 JavaValue result(T_OBJECT);
72 JavaCallArguments args;
73
74
75 Symbol* signature = vmSymbols::serializePropertiesToByteArray_signature();
76 JavaCalls::call_static(&result,
77 ik,
78 serializePropertiesMethod,
79 signature,
80 &args,
81 THREAD);
82 if (HAS_PENDING_EXCEPTION) {
83 java_lang_Throwable::print(PENDING_EXCEPTION, out);
84 CLEAR_PENDING_EXCEPTION;
85 return JNI_ERR;
86 }
87
88 // The result should be a [B
89 oop res = (oop)result.get_jobject();
90 assert(res->is_typeArray(), "just checking");
91 assert(TypeArrayKlass::cast(res->klass())->element_type() == T_BYTE, "just checking");
92
93 // copy the bytes to the output stream
94 typeArrayOop ba = typeArrayOop(res);
95 jbyte* addr = typeArrayOop(res)->byte_at_addr(0);
96 out->print_raw((const char*)addr, ba->length());
97
98 return JNI_OK;
99 }
100
101 // Implementation of "properties" command.
102 // See also: PrintSystemPropertiesDCmd class
103 static jint get_system_properties(AttachOperation* op, outputStream* out) {
104 return get_properties(op, out, vmSymbols::serializePropertiesToByteArray_name());
105 }
106
107 // Implementation of "agent_properties" command.
108 static jint get_agent_properties(AttachOperation* op, outputStream* out) {
109 return get_properties(op, out, vmSymbols::serializeAgentPropertiesToByteArray_name());
110 }
111
112 // Implementation of "datadump" command.
113 //
114 // Raises a SIGBREAK signal so that VM dump threads, does deadlock detection,
115 // etc. In theory this command should only post a DataDumpRequest to any
116 // JVMTI environment that has enabled this event. However it's useful to
117 // trigger the SIGBREAK handler.
118
119 static jint data_dump(AttachOperation* op, outputStream* out) {
120 if (!ReduceSignalUsage) {
121 AttachListener::pd_data_dump();
122 } else {
123 if (JvmtiExport::should_post_data_dump()) {
124 JvmtiExport::post_data_dump();
125 }
126 }
127 return JNI_OK;
128 }
129
130 // Implementation of "threaddump" command - essentially a remote ctrl-break
131 // See also: ThreadDumpDCmd class
132 //
133 static jint thread_dump(AttachOperation* op, outputStream* out) {
134 bool print_concurrent_locks = false;
135 if (op->arg(0) != NULL && strcmp(op->arg(0), "-l") == 0) {
136 print_concurrent_locks = true;
137 }
138
139 // thread stacks
140 VM_PrintThreads op1(out, print_concurrent_locks);
141 VMThread::execute(&op1);
142
143 // JNI global handles
144 VM_PrintJNI op2(out);
145 VMThread::execute(&op2);
146
147 // Deadlock detection
148 VM_FindDeadlocks op3(out);
149 VMThread::execute(&op3);
150
151 return JNI_OK;
152 }
153
154 // A jcmd attach operation request was received, which will now
155 // dispatch to the diagnostic commands used for serviceability functions.
156 static jint jcmd(AttachOperation* op, outputStream* out) {
157 Thread* THREAD = Thread::current();
158 // All the supplied jcmd arguments are stored as a single
159 // string (op->arg(0)). This is parsed by the Dcmd framework.
160 DCmd::parse_and_execute(DCmd_Source_AttachAPI, out, op->arg(0), ' ', THREAD);
161 if (HAS_PENDING_EXCEPTION) {
162 java_lang_Throwable::print(PENDING_EXCEPTION, out);
163 out->cr();
164 CLEAR_PENDING_EXCEPTION;
165 // The exception has been printed on the output stream
166 // If the JVM returns JNI_ERR, the attachAPI throws a generic I/O
167 // exception and the content of the output stream is not processed.
168 // By returning JNI_OK, the exception will be displayed on the client side
169 }
170 return JNI_OK;
171 }
172
173 // Implementation of "dumpheap" command.
174 // See also: HeapDumpDCmd class
175 //
176 // Input arguments :-
177 // arg0: Name of the dump file
178 // arg1: "-live" or "-all"
179 jint dump_heap(AttachOperation* op, outputStream* out) {
180 const char* path = op->arg(0);
181 if (path == NULL || path[0] == '\0') {
182 out->print_cr("No dump file specified");
183 } else {
184 bool live_objects_only = true; // default is true to retain the behavior before this change is made
185 const char* arg1 = op->arg(1);
186 if (arg1 != NULL && (strlen(arg1) > 0)) {
187 if (strcmp(arg1, "-all") != 0 && strcmp(arg1, "-live") != 0) {
188 out->print_cr("Invalid argument to dumpheap operation: %s", arg1);
189 return JNI_ERR;
190 }
191 live_objects_only = strcmp(arg1, "-live") == 0;
192 }
193
194 // Request a full GC before heap dump if live_objects_only = true
195 // This helps reduces the amount of unreachable objects in the dump
196 // and makes it easier to browse.
197 HeapDumper dumper(live_objects_only /* request GC */);
198 int res = dumper.dump(op->arg(0));
199 if (res == 0) {
200 out->print_cr("Heap dump file created");
201 } else {
202 // heap dump failed
203 ResourceMark rm;
204 char* error = dumper.error_as_C_string();
205 if (error == NULL) {
206 out->print_cr("Dump failed - reason unknown");
207 } else {
208 out->print_cr("%s", error);
209 }
210 }
211 }
212 return JNI_OK;
213 }
214
215 // Implementation of "inspectheap" command
216 // See also: ClassHistogramDCmd class
217 //
218 // Input arguments :-
219 // arg0: "-live" or "-all"
220 static jint heap_inspection(AttachOperation* op, outputStream* out) {
221 bool live_objects_only = true; // default is true to retain the behavior before this change is made
222 const char* arg0 = op->arg(0);
223 if (arg0 != NULL && (strlen(arg0) > 0)) {
224 if (strcmp(arg0, "-all") != 0 && strcmp(arg0, "-live") != 0) {
225 out->print_cr("Invalid argument to inspectheap operation: %s", arg0);
226 return JNI_ERR;
227 }
228 live_objects_only = strcmp(arg0, "-live") == 0;
229 }
230 VM_GC_HeapInspection heapop(out, live_objects_only /* request full gc */);
231 VMThread::execute(&heapop);
232 return JNI_OK;
233 }
234
235 // set a boolean global flag using value from AttachOperation
236 static jint set_bool_flag(const char* name, AttachOperation* op, outputStream* out) {
237 bool value = true;
238 const char* arg1;
239 if ((arg1 = op->arg(1)) != NULL) {
240 int tmp;
241 int n = sscanf(arg1, "%d", &tmp);
242 if (n != 1) {
243 out->print_cr("flag value must be a boolean (1 or 0)");
244 return JNI_ERR;
245 }
246 value = (tmp != 0);
247 }
248 bool res = CommandLineFlags::boolAtPut((char*)name, &value, ATTACH_ON_DEMAND);
249 if (! res) {
250 out->print_cr("setting flag %s failed", name);
251 }
252 return res? JNI_OK : JNI_ERR;
253 }
254
255 // set a intx global flag using value from AttachOperation
256 static jint set_intx_flag(const char* name, AttachOperation* op, outputStream* out) {
257 intx value;
258 const char* arg1;
259 if ((arg1 = op->arg(1)) != NULL) {
260 int n = sscanf(arg1, INTX_FORMAT, &value);
261 if (n != 1) {
262 out->print_cr("flag value must be an integer");
263 return JNI_ERR;
264 }
265 }
266 bool res = CommandLineFlags::intxAtPut((char*)name, &value, ATTACH_ON_DEMAND);
267 if (! res) {
268 out->print_cr("setting flag %s failed", name);
269 }
270
271 return res? JNI_OK : JNI_ERR;
272 }
273
274 // set a uintx global flag using value from AttachOperation
275 static jint set_uintx_flag(const char* name, AttachOperation* op, outputStream* out) {
276 uintx value;
277 const char* arg1;
278 if ((arg1 = op->arg(1)) != NULL) {
279 int n = sscanf(arg1, UINTX_FORMAT, &value);
280 if (n != 1) {
281 out->print_cr("flag value must be an unsigned integer");
282 return JNI_ERR;
283 }
284 }
285 bool res = CommandLineFlags::uintxAtPut((char*)name, &value, ATTACH_ON_DEMAND);
286 if (! res) {
287 out->print_cr("setting flag %s failed", name);
288 }
289
290 return res? JNI_OK : JNI_ERR;
291 }
292
293 // set a uint64_t global flag using value from AttachOperation
294 static jint set_uint64_t_flag(const char* name, AttachOperation* op, outputStream* out) {
295 uint64_t value;
296 const char* arg1;
297 if ((arg1 = op->arg(1)) != NULL) {
298 int n = sscanf(arg1, UINT64_FORMAT, &value);
299 if (n != 1) {
300 out->print_cr("flag value must be an unsigned 64-bit integer");
301 return JNI_ERR;
302 }
303 }
304 bool res = CommandLineFlags::uint64_tAtPut((char*)name, &value, ATTACH_ON_DEMAND);
305 if (! res) {
306 out->print_cr("setting flag %s failed", name);
307 }
308
309 return res? JNI_OK : JNI_ERR;
310 }
311
312 // set a string global flag using value from AttachOperation
313 static jint set_ccstr_flag(const char* name, AttachOperation* op, outputStream* out) {
314 const char* value;
315 if ((value = op->arg(1)) == NULL) {
316 out->print_cr("flag value must be a string");
317 return JNI_ERR;
318 }
319 bool res = CommandLineFlags::ccstrAtPut((char*)name, &value, ATTACH_ON_DEMAND);
320 if (res) {
321 FREE_C_HEAP_ARRAY(char, value, mtInternal);
322 } else {
323 out->print_cr("setting flag %s failed", name);
324 }
325
326 return res? JNI_OK : JNI_ERR;
327 }
328
329 // Implementation of "setflag" command
330 static jint set_flag(AttachOperation* op, outputStream* out) {
331
332 const char* name = NULL;
333 if ((name = op->arg(0)) == NULL) {
334 out->print_cr("flag name is missing");
335 return JNI_ERR;
336 }
337
338 Flag* f = Flag::find_flag((char*)name, strlen(name));
339 if (f && f->is_external() && f->is_writeable()) {
340 if (f->is_bool()) {
341 return set_bool_flag(name, op, out);
342 } else if (f->is_intx()) {
343 return set_intx_flag(name, op, out);
344 } else if (f->is_uintx()) {
345 return set_uintx_flag(name, op, out);
346 } else if (f->is_uint64_t()) {
347 return set_uint64_t_flag(name, op, out);
348 } else if (f->is_ccstr()) {
349 return set_ccstr_flag(name, op, out);
350 } else {
351 ShouldNotReachHere();
352 return JNI_ERR;
353 }
354 } else {
355 return AttachListener::pd_set_flag(op, out);
356 }
357 }
358
359 // Implementation of "printflag" command
360 // See also: PrintVMFlagsDCmd class
361 static jint print_flag(AttachOperation* op, outputStream* out) {
362 const char* name = NULL;
363 if ((name = op->arg(0)) == NULL) {
364 out->print_cr("flag name is missing");
365 return JNI_ERR;
366 }
367 Flag* f = Flag::find_flag((char*)name, strlen(name));
368 if (f) {
369 f->print_as_flag(out);
370 out->print_cr("");
371 } else {
372 out->print_cr("no such flag '%s'", name);
373 }
374 return JNI_OK;
375 }
376
377 // Table to map operation names to functions.
378
379 // names must be of length <= AttachOperation::name_length_max
380 static AttachOperationFunctionInfo funcs[] = {
381 { "agentProperties", get_agent_properties },
382 { "datadump", data_dump },
383 { "dumpheap", dump_heap },
384 { "load", JvmtiExport::load_agent_library },
385 { "properties", get_system_properties },
386 { "threaddump", thread_dump },
387 { "inspectheap", heap_inspection },
388 { "setflag", set_flag },
389 { "printflag", print_flag },
390 { "jcmd", jcmd },
391 { NULL, NULL }
392 };
393
394
395
396 // The Attach Listener threads services a queue. It dequeues an operation
397 // from the queue, examines the operation name (command), and dispatches
398 // to the corresponding function to perform the operation.
399
400 static void attach_listener_thread_entry(JavaThread* thread, TRAPS) {
401 os::set_priority(thread, NearMaxPriority);
402
403 thread->record_stack_base_and_size();
404
405 if (AttachListener::pd_init() != 0) {
406 return;
407 }
408 AttachListener::set_initialized();
409
410 for (;;) {
411 AttachOperation* op = AttachListener::dequeue();
412 if (op == NULL) {
413 return; // dequeue failed or shutdown
414 }
415
416 ResourceMark rm;
417 bufferedStream st;
418 jint res = JNI_OK;
419
420 // handle special detachall operation
421 if (strcmp(op->name(), AttachOperation::detachall_operation_name()) == 0) {
422 AttachListener::detachall();
423 } else {
424 // find the function to dispatch too
425 AttachOperationFunctionInfo* info = NULL;
426 for (int i=0; funcs[i].name != NULL; i++) {
427 const char* name = funcs[i].name;
428 assert(strlen(name) <= AttachOperation::name_length_max, "operation <= name_length_max");
429 if (strcmp(op->name(), name) == 0) {
430 info = &(funcs[i]);
431 break;
432 }
433 }
434
435 // check for platform dependent attach operation
436 if (info == NULL) {
437 info = AttachListener::pd_find_operation(op->name());
438 }
439
440 if (info != NULL) {
441 // dispatch to the function that implements this operation
442 res = (info->func)(op, &st);
443 } else {
444 st.print("Operation %s not recognized!", op->name());
445 res = JNI_ERR;
446 }
447 }
448
449 // operation complete - send result and output to client
450 op->complete(res, &st);
451 }
452 }
453
454 // Starts the Attach Listener thread
455 void AttachListener::init() {
456 EXCEPTION_MARK;
457 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
458 instanceKlassHandle klass (THREAD, k);
459 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
460
461 const char thread_name[] = "Attach Listener";
462 Handle string = java_lang_String::create_from_str(thread_name, CHECK);
463
464 // Initialize thread_oop to put it into the system threadGroup
465 Handle thread_group (THREAD, Universe::system_thread_group());
466 JavaValue result(T_VOID);
467 JavaCalls::call_special(&result, thread_oop,
468 klass,
469 vmSymbols::object_initializer_name(),
470 vmSymbols::threadgroup_string_void_signature(),
471 thread_group,
472 string,
473 CHECK);
474
475 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
476 JavaCalls::call_special(&result,
477 thread_group,
478 group,
479 vmSymbols::add_method_name(),
480 vmSymbols::thread_void_signature(),
481 thread_oop, // ARG 1
482 CHECK);
483
484 { MutexLocker mu(Threads_lock);
485 JavaThread* listener_thread = new JavaThread(&attach_listener_thread_entry);
486
487 // Check that thread and osthread were created
488 if (listener_thread == NULL || listener_thread->osthread() == NULL) {
489 vm_exit_during_initialization("java.lang.OutOfMemoryError",
490 "unable to create new native thread");
491 }
492
493 java_lang_Thread::set_thread(thread_oop(), listener_thread);
494 java_lang_Thread::set_daemon(thread_oop());
495
496 listener_thread->set_threadObj(thread_oop());
497 Threads::add(listener_thread);
498 Thread::start(listener_thread);
499 }
500 }
501
502 // Performs clean-up tasks on platforms where we can detect that the last
503 // client has detached
504 void AttachListener::detachall() {
505 // call the platform dependent clean-up
506 pd_detachall();
507 }