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 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 // 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(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 */, true /* need_prologue */); 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 klassOop 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 THREAD); 474 475 if (HAS_PENDING_EXCEPTION) { 476 tty->print_cr("Exception in VM (AttachListener::init) : "); 477 java_lang_Throwable::print(PENDING_EXCEPTION, tty); 478 tty->cr(); 479 480 CLEAR_PENDING_EXCEPTION; 481 482 return; 483 } 484 485 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass()); 486 JavaCalls::call_special(&result, 487 thread_group, 488 group, 489 vmSymbols::add_method_name(), 490 vmSymbols::thread_void_signature(), 491 thread_oop, // ARG 1 492 THREAD); 493 494 if (HAS_PENDING_EXCEPTION) { 495 tty->print_cr("Exception in VM (AttachListener::init) : "); 496 java_lang_Throwable::print(PENDING_EXCEPTION, tty); 497 tty->cr(); 498 499 CLEAR_PENDING_EXCEPTION; 500 501 return; 502 } 503 504 { MutexLocker mu(Threads_lock); 505 JavaThread* listener_thread = new JavaThread(&attach_listener_thread_entry); 506 507 // Check that thread and osthread were created 508 if (listener_thread == NULL || listener_thread->osthread() == NULL) { 509 vm_exit_during_initialization("java.lang.OutOfMemoryError", 510 "unable to create new native thread"); 511 } 512 513 java_lang_Thread::set_thread(thread_oop(), listener_thread); 514 java_lang_Thread::set_daemon(thread_oop()); 515 516 listener_thread->set_threadObj(thread_oop()); 517 Threads::add(listener_thread); 518 Thread::start(listener_thread); 519 } 520 } 521 522 // Performs clean-up tasks on platforms where we can detect that the last 523 // client has detached 524 void AttachListener::detachall() { 525 // call the platform dependent clean-up 526 pd_detachall(); 527 }