1 /*
2 * Copyright (c) 2005, 2011, 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/heapDumper.hpp"
38 #include "services/diagnosticCommand.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 klassOop load_and_initialize_klass(Symbol* sh, TRAPS) {
48 klassOop 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 klassOop 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 static jint get_system_properties(AttachOperation* op, outputStream* out) {
103 return get_properties(op, out, vmSymbols::serializePropertiesToByteArray_name());
104 }
105
106 // Implementation of "agent_properties" command.
107 static jint get_agent_properties(AttachOperation* op, outputStream* out) {
108 return get_properties(op, out, vmSymbols::serializeAgentPropertiesToByteArray_name());
109 }
110
111 // Implementation of "datadump" command.
112 //
113 // Raises a SIGBREAK signal so that VM dump threads, does deadlock detection,
114 // etc. In theory this command should only post a DataDumpRequest to any
115 // JVMTI environment that has enabled this event. However it's useful to
116 // trigger the SIGBREAK handler.
117
118 static jint data_dump(AttachOperation* op, outputStream* out) {
119 if (!ReduceSignalUsage) {
120 AttachListener::pd_data_dump();
121 } else {
122 if (JvmtiExport::should_post_data_dump()) {
123 JvmtiExport::post_data_dump();
124 }
125 }
126 return JNI_OK;
127 }
128
129 // Implementation of "threaddump" command - essentially a remote ctrl-break
130 //
131 static jint thread_dump(AttachOperation* op, outputStream* out) {
132 bool print_concurrent_locks = false;
133 if (op->arg(0) != NULL && strcmp(op->arg(0), "-l") == 0) {
134 print_concurrent_locks = true;
135 }
136
137 // thread stacks
138 VM_PrintThreads op1(out, print_concurrent_locks);
139 VMThread::execute(&op1);
140
141 // JNI global handles
142 VM_PrintJNI op2(out);
143 VMThread::execute(&op2);
144
145 // Deadlock detection
146 VM_FindDeadlocks op3(out);
147 VMThread::execute(&op3);
148
149 return JNI_OK;
150 }
151
152 /**
153 * A jcmd attach operation request was received, which will now
154 * dispatch to the diagnostic commands used for serviceability functions.
155 */
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(out, op->arg(0), ' ', THREAD);
161 if (HAS_PENDING_EXCEPTION) {
162 java_lang_Throwable::print(PENDING_EXCEPTION, out);
163 CLEAR_PENDING_EXCEPTION;
164 // The exception has been printed on the output stream
165 // If the JVM returns JNI_ERR, the attachAPI throws a generic I/O
166 // exception and the content of the output stream is not processed.
167 // By returning JNI_OK, the exception will be displayed on the client side
168 }
169 return JNI_OK;
170 }
171
172 #ifndef SERVICES_KERNEL // Heap dumping not supported
173 // Implementation of "dumpheap" command.
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 #endif // SERVICES_KERNEL
214
215 // Implementation of "inspectheap" command
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 */, true /* need_prologue */);
230 VMThread::execute(&heapop);
231 return JNI_OK;
232 }
233
234 // set a boolean global flag using value from AttachOperation
235 static jint set_bool_flag(const char* name, AttachOperation* op, outputStream* out) {
236 bool value = true;
237 const char* arg1;
238 if ((arg1 = op->arg(1)) != NULL) {
239 int tmp;
240 int n = sscanf(arg1, "%d", &tmp);
241 if (n != 1) {
242 out->print_cr("flag value must be a boolean (1 or 0)");
243 return JNI_ERR;
244 }
245 value = (tmp != 0);
246 }
247 bool res = CommandLineFlags::boolAtPut((char*)name, &value, ATTACH_ON_DEMAND);
248 if (! res) {
249 out->print_cr("setting flag %s failed", name);
250 }
251 return res? JNI_OK : JNI_ERR;
252 }
253
254 // set a intx global flag using value from AttachOperation
255 static jint set_intx_flag(const char* name, AttachOperation* op, outputStream* out) {
256 intx value;
257 const char* arg1;
258 if ((arg1 = op->arg(1)) != NULL) {
259 int n = sscanf(arg1, INTX_FORMAT, &value);
260 if (n != 1) {
261 out->print_cr("flag value must be an integer");
262 return JNI_ERR;
263 }
264 }
265 bool res = CommandLineFlags::intxAtPut((char*)name, &value, ATTACH_ON_DEMAND);
266 if (! res) {
267 out->print_cr("setting flag %s failed", name);
268 }
269
270 return res? JNI_OK : JNI_ERR;
271 }
272
273 // set a uintx global flag using value from AttachOperation
274 static jint set_uintx_flag(const char* name, AttachOperation* op, outputStream* out) {
275 uintx value;
276 const char* arg1;
277 if ((arg1 = op->arg(1)) != NULL) {
278 int n = sscanf(arg1, UINTX_FORMAT, &value);
279 if (n != 1) {
280 out->print_cr("flag value must be an unsigned integer");
281 return JNI_ERR;
282 }
283 }
284 bool res = CommandLineFlags::uintxAtPut((char*)name, &value, ATTACH_ON_DEMAND);
285 if (! res) {
286 out->print_cr("setting flag %s failed", name);
287 }
288
289 return res? JNI_OK : JNI_ERR;
290 }
291
292 // set a uint64_t global flag using value from AttachOperation
293 static jint set_uint64_t_flag(const char* name, AttachOperation* op, outputStream* out) {
294 uint64_t value;
295 const char* arg1;
296 if ((arg1 = op->arg(1)) != NULL) {
297 int n = sscanf(arg1, UINT64_FORMAT, &value);
298 if (n != 1) {
299 out->print_cr("flag value must be an unsigned 64-bit integer");
300 return JNI_ERR;
301 }
302 }
303 bool res = CommandLineFlags::uint64_tAtPut((char*)name, &value, ATTACH_ON_DEMAND);
304 if (! res) {
305 out->print_cr("setting flag %s failed", name);
306 }
307
308 return res? JNI_OK : JNI_ERR;
309 }
310
311 // set a string global flag using value from AttachOperation
312 static jint set_ccstr_flag(const char* name, AttachOperation* op, outputStream* out) {
313 const char* value;
314 if ((value = op->arg(1)) == NULL) {
315 out->print_cr("flag value must be a string");
316 return JNI_ERR;
317 }
318 bool res = CommandLineFlags::ccstrAtPut((char*)name, &value, ATTACH_ON_DEMAND);
319 if (res) {
320 FREE_C_HEAP_ARRAY(char, value);
321 } else {
322 out->print_cr("setting flag %s failed", name);
323 }
324
325 return res? JNI_OK : JNI_ERR;
326 }
327
328 // Implementation of "setflag" command
329 static jint set_flag(AttachOperation* op, outputStream* out) {
330
331 const char* name = NULL;
332 if ((name = op->arg(0)) == NULL) {
333 out->print_cr("flag name is missing");
334 return JNI_ERR;
335 }
336
337 Flag* f = Flag::find_flag((char*)name, strlen(name));
338 if (f && f->is_external() && f->is_writeable()) {
339 if (f->is_bool()) {
340 return set_bool_flag(name, op, out);
341 } else if (f->is_intx()) {
342 return set_intx_flag(name, op, out);
343 } else if (f->is_uintx()) {
344 return set_uintx_flag(name, op, out);
345 } else if (f->is_uint64_t()) {
346 return set_uint64_t_flag(name, op, out);
347 } else if (f->is_ccstr()) {
348 return set_ccstr_flag(name, op, out);
349 } else {
350 ShouldNotReachHere();
351 return JNI_ERR;
352 }
353 } else {
354 return AttachListener::pd_set_flag(op, out);
355 }
356 }
357
358 // Implementation of "printflag" command
359 static jint print_flag(AttachOperation* op, outputStream* out) {
360 const char* name = NULL;
361 if ((name = op->arg(0)) == NULL) {
362 out->print_cr("flag name is missing");
363 return JNI_ERR;
364 }
365 Flag* f = Flag::find_flag((char*)name, strlen(name));
366 if (f) {
367 f->print_as_flag(out);
368 out->print_cr("");
369 } else {
370 out->print_cr("no such flag '%s'", name);
371 }
372 return JNI_OK;
373 }
374
375 // Table to map operation names to functions.
376
377 // names must be of length <= AttachOperation::name_length_max
378 static AttachOperationFunctionInfo funcs[] = {
379 { "agentProperties", get_agent_properties },
380 { "datadump", data_dump },
381 #ifndef SERVICES_KERNEL
382 { "dumpheap", dump_heap },
383 #endif // SERVICES_KERNEL
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 if (AttachListener::pd_init() != 0) {
404 return;
405 }
406 AttachListener::set_initialized();
407
408 for (;;) {
409 AttachOperation* op = AttachListener::dequeue();
410 if (op == NULL) {
411 return; // dequeue failed or shutdown
412 }
413
414 ResourceMark rm;
415 bufferedStream st;
416 jint res = JNI_OK;
417
418 // handle special detachall operation
419 if (strcmp(op->name(), AttachOperation::detachall_operation_name()) == 0) {
420 AttachListener::detachall();
421 } else {
422 // find the function to dispatch too
423 AttachOperationFunctionInfo* info = NULL;
424 for (int i=0; funcs[i].name != NULL; i++) {
425 const char* name = funcs[i].name;
426 assert(strlen(name) <= AttachOperation::name_length_max, "operation <= name_length_max");
427 if (strcmp(op->name(), name) == 0) {
428 info = &(funcs[i]);
429 break;
430 }
431 }
432
433 // check for platform dependent attach operation
434 if (info == NULL) {
435 info = AttachListener::pd_find_operation(op->name());
436 }
437
438 if (info != NULL) {
439 // dispatch to the function that implements this operation
440 res = (info->func)(op, &st);
441 } else {
442 st.print("Operation %s not recognized!", op->name());
443 res = JNI_ERR;
444 }
445 }
446
447 // operation complete - send result and output to client
448 op->complete(res, &st);
449 }
450 }
451
452 // Starts the Attach Listener thread
453 void AttachListener::init() {
454 EXCEPTION_MARK;
455 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
456 instanceKlassHandle klass (THREAD, k);
457 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
458
459 const char thread_name[] = "Attach Listener";
460 Handle string = java_lang_String::create_from_str(thread_name, CHECK);
461
462 // Initialize thread_oop to put it into the system threadGroup
463 Handle thread_group (THREAD, Universe::system_thread_group());
464 JavaValue result(T_VOID);
465 JavaCalls::call_special(&result, thread_oop,
466 klass,
467 vmSymbols::object_initializer_name(),
468 vmSymbols::threadgroup_string_void_signature(),
469 thread_group,
470 string,
471 CHECK);
472
473 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
474 JavaCalls::call_special(&result,
475 thread_group,
476 group,
477 vmSymbols::add_method_name(),
478 vmSymbols::thread_void_signature(),
479 thread_oop, // ARG 1
480 CHECK);
481
482 { MutexLocker mu(Threads_lock);
483 JavaThread* listener_thread = new JavaThread(&attach_listener_thread_entry);
484
485 // Check that thread and osthread were created
486 if (listener_thread == NULL || listener_thread->osthread() == NULL) {
487 vm_exit_during_initialization("java.lang.OutOfMemoryError",
488 "unable to create new native thread");
489 }
490
491 java_lang_Thread::set_thread(thread_oop(), listener_thread);
492 java_lang_Thread::set_daemon(thread_oop());
493
494 listener_thread->set_threadObj(thread_oop());
495 Threads::add(listener_thread);
496 Thread::start(listener_thread);
497 }
498 }
499
500 // Performs clean-up tasks on platforms where we can detect that the last
501 // client has detached
502 void AttachListener::detachall() {
503 // call the platform dependent clean-up
504 pd_detachall();
505 }