attachListener.cpp revision 3465:d2a62e0f25eb
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/diagnosticCommand.hpp" 38#include "services/heapDumper.hpp" 39 40volatile 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 47static 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 56static 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 103static 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. 108static 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 119static 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// 133static 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. 156static 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#ifndef SERVICES_KERNEL // Heap dumping not supported 174// Implementation of "dumpheap" command. 175// See also: HeapDumpDCmd class 176// 177// Input arguments :- 178// arg0: Name of the dump file 179// arg1: "-live" or "-all" 180jint dump_heap(AttachOperation* op, outputStream* out) { 181 const char* path = op->arg(0); 182 if (path == NULL || path[0] == '\0') { 183 out->print_cr("No dump file specified"); 184 } else { 185 bool live_objects_only = true; // default is true to retain the behavior before this change is made 186 const char* arg1 = op->arg(1); 187 if (arg1 != NULL && (strlen(arg1) > 0)) { 188 if (strcmp(arg1, "-all") != 0 && strcmp(arg1, "-live") != 0) { 189 out->print_cr("Invalid argument to dumpheap operation: %s", arg1); 190 return JNI_ERR; 191 } 192 live_objects_only = strcmp(arg1, "-live") == 0; 193 } 194 195 // Request a full GC before heap dump if live_objects_only = true 196 // This helps reduces the amount of unreachable objects in the dump 197 // and makes it easier to browse. 198 HeapDumper dumper(live_objects_only /* request GC */); 199 int res = dumper.dump(op->arg(0)); 200 if (res == 0) { 201 out->print_cr("Heap dump file created"); 202 } else { 203 // heap dump failed 204 ResourceMark rm; 205 char* error = dumper.error_as_C_string(); 206 if (error == NULL) { 207 out->print_cr("Dump failed - reason unknown"); 208 } else { 209 out->print_cr("%s", error); 210 } 211 } 212 } 213 return JNI_OK; 214} 215#endif // SERVICES_KERNEL 216 217// Implementation of "inspectheap" command 218// See also: ClassHistogramDCmd class 219// 220// Input arguments :- 221// arg0: "-live" or "-all" 222static jint heap_inspection(AttachOperation* op, outputStream* out) { 223 bool live_objects_only = true; // default is true to retain the behavior before this change is made 224 const char* arg0 = op->arg(0); 225 if (arg0 != NULL && (strlen(arg0) > 0)) { 226 if (strcmp(arg0, "-all") != 0 && strcmp(arg0, "-live") != 0) { 227 out->print_cr("Invalid argument to inspectheap operation: %s", arg0); 228 return JNI_ERR; 229 } 230 live_objects_only = strcmp(arg0, "-live") == 0; 231 } 232 VM_GC_HeapInspection heapop(out, live_objects_only /* request full gc */, true /* need_prologue */); 233 VMThread::execute(&heapop); 234 return JNI_OK; 235} 236 237// set a boolean global flag using value from AttachOperation 238static jint set_bool_flag(const char* name, AttachOperation* op, outputStream* out) { 239 bool value = true; 240 const char* arg1; 241 if ((arg1 = op->arg(1)) != NULL) { 242 int tmp; 243 int n = sscanf(arg1, "%d", &tmp); 244 if (n != 1) { 245 out->print_cr("flag value must be a boolean (1 or 0)"); 246 return JNI_ERR; 247 } 248 value = (tmp != 0); 249 } 250 bool res = CommandLineFlags::boolAtPut((char*)name, &value, ATTACH_ON_DEMAND); 251 if (! res) { 252 out->print_cr("setting flag %s failed", name); 253 } 254 return res? JNI_OK : JNI_ERR; 255} 256 257// set a intx global flag using value from AttachOperation 258static jint set_intx_flag(const char* name, AttachOperation* op, outputStream* out) { 259 intx value; 260 const char* arg1; 261 if ((arg1 = op->arg(1)) != NULL) { 262 int n = sscanf(arg1, INTX_FORMAT, &value); 263 if (n != 1) { 264 out->print_cr("flag value must be an integer"); 265 return JNI_ERR; 266 } 267 } 268 bool res = CommandLineFlags::intxAtPut((char*)name, &value, ATTACH_ON_DEMAND); 269 if (! res) { 270 out->print_cr("setting flag %s failed", name); 271 } 272 273 return res? JNI_OK : JNI_ERR; 274} 275 276// set a uintx global flag using value from AttachOperation 277static jint set_uintx_flag(const char* name, AttachOperation* op, outputStream* out) { 278 uintx value; 279 const char* arg1; 280 if ((arg1 = op->arg(1)) != NULL) { 281 int n = sscanf(arg1, UINTX_FORMAT, &value); 282 if (n != 1) { 283 out->print_cr("flag value must be an unsigned integer"); 284 return JNI_ERR; 285 } 286 } 287 bool res = CommandLineFlags::uintxAtPut((char*)name, &value, ATTACH_ON_DEMAND); 288 if (! res) { 289 out->print_cr("setting flag %s failed", name); 290 } 291 292 return res? JNI_OK : JNI_ERR; 293} 294 295// set a uint64_t global flag using value from AttachOperation 296static jint set_uint64_t_flag(const char* name, AttachOperation* op, outputStream* out) { 297 uint64_t value; 298 const char* arg1; 299 if ((arg1 = op->arg(1)) != NULL) { 300 int n = sscanf(arg1, UINT64_FORMAT, &value); 301 if (n != 1) { 302 out->print_cr("flag value must be an unsigned 64-bit integer"); 303 return JNI_ERR; 304 } 305 } 306 bool res = CommandLineFlags::uint64_tAtPut((char*)name, &value, ATTACH_ON_DEMAND); 307 if (! res) { 308 out->print_cr("setting flag %s failed", name); 309 } 310 311 return res? JNI_OK : JNI_ERR; 312} 313 314// set a string global flag using value from AttachOperation 315static jint set_ccstr_flag(const char* name, AttachOperation* op, outputStream* out) { 316 const char* value; 317 if ((value = op->arg(1)) == NULL) { 318 out->print_cr("flag value must be a string"); 319 return JNI_ERR; 320 } 321 bool res = CommandLineFlags::ccstrAtPut((char*)name, &value, ATTACH_ON_DEMAND); 322 if (res) { 323 FREE_C_HEAP_ARRAY(char, value, mtInternal); 324 } else { 325 out->print_cr("setting flag %s failed", name); 326 } 327 328 return res? JNI_OK : JNI_ERR; 329} 330 331// Implementation of "setflag" command 332static jint set_flag(AttachOperation* op, outputStream* out) { 333 334 const char* name = NULL; 335 if ((name = op->arg(0)) == NULL) { 336 out->print_cr("flag name is missing"); 337 return JNI_ERR; 338 } 339 340 Flag* f = Flag::find_flag((char*)name, strlen(name)); 341 if (f && f->is_external() && f->is_writeable()) { 342 if (f->is_bool()) { 343 return set_bool_flag(name, op, out); 344 } else if (f->is_intx()) { 345 return set_intx_flag(name, op, out); 346 } else if (f->is_uintx()) { 347 return set_uintx_flag(name, op, out); 348 } else if (f->is_uint64_t()) { 349 return set_uint64_t_flag(name, op, out); 350 } else if (f->is_ccstr()) { 351 return set_ccstr_flag(name, op, out); 352 } else { 353 ShouldNotReachHere(); 354 return JNI_ERR; 355 } 356 } else { 357 return AttachListener::pd_set_flag(op, out); 358 } 359} 360 361// Implementation of "printflag" command 362// See also: PrintVMFlagsDCmd class 363static jint print_flag(AttachOperation* op, outputStream* out) { 364 const char* name = NULL; 365 if ((name = op->arg(0)) == NULL) { 366 out->print_cr("flag name is missing"); 367 return JNI_ERR; 368 } 369 Flag* f = Flag::find_flag((char*)name, strlen(name)); 370 if (f) { 371 f->print_as_flag(out); 372 out->print_cr(""); 373 } else { 374 out->print_cr("no such flag '%s'", name); 375 } 376 return JNI_OK; 377} 378 379// Table to map operation names to functions. 380 381// names must be of length <= AttachOperation::name_length_max 382static AttachOperationFunctionInfo funcs[] = { 383 { "agentProperties", get_agent_properties }, 384 { "datadump", data_dump }, 385#ifndef SERVICES_KERNEL 386 { "dumpheap", dump_heap }, 387#endif // SERVICES_KERNEL 388 { "load", JvmtiExport::load_agent_library }, 389 { "properties", get_system_properties }, 390 { "threaddump", thread_dump }, 391 { "inspectheap", heap_inspection }, 392 { "setflag", set_flag }, 393 { "printflag", print_flag }, 394 { "jcmd", jcmd }, 395 { NULL, NULL } 396}; 397 398 399 400// The Attach Listener threads services a queue. It dequeues an operation 401// from the queue, examines the operation name (command), and dispatches 402// to the corresponding function to perform the operation. 403 404static void attach_listener_thread_entry(JavaThread* thread, TRAPS) { 405 os::set_priority(thread, NearMaxPriority); 406 407 if (AttachListener::pd_init() != 0) { 408 return; 409 } 410 AttachListener::set_initialized(); 411 412 for (;;) { 413 AttachOperation* op = AttachListener::dequeue(); 414 if (op == NULL) { 415 return; // dequeue failed or shutdown 416 } 417 418 ResourceMark rm; 419 bufferedStream st; 420 jint res = JNI_OK; 421 422 // handle special detachall operation 423 if (strcmp(op->name(), AttachOperation::detachall_operation_name()) == 0) { 424 AttachListener::detachall(); 425 } else { 426 // find the function to dispatch too 427 AttachOperationFunctionInfo* info = NULL; 428 for (int i=0; funcs[i].name != NULL; i++) { 429 const char* name = funcs[i].name; 430 assert(strlen(name) <= AttachOperation::name_length_max, "operation <= name_length_max"); 431 if (strcmp(op->name(), name) == 0) { 432 info = &(funcs[i]); 433 break; 434 } 435 } 436 437 // check for platform dependent attach operation 438 if (info == NULL) { 439 info = AttachListener::pd_find_operation(op->name()); 440 } 441 442 if (info != NULL) { 443 // dispatch to the function that implements this operation 444 res = (info->func)(op, &st); 445 } else { 446 st.print("Operation %s not recognized!", op->name()); 447 res = JNI_ERR; 448 } 449 } 450 451 // operation complete - send result and output to client 452 op->complete(res, &st); 453 } 454} 455 456// Starts the Attach Listener thread 457void AttachListener::init() { 458 EXCEPTION_MARK; 459 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 460 instanceKlassHandle klass (THREAD, k); 461 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 462 463 const char thread_name[] = "Attach Listener"; 464 Handle string = java_lang_String::create_from_str(thread_name, CHECK); 465 466 // Initialize thread_oop to put it into the system threadGroup 467 Handle thread_group (THREAD, Universe::system_thread_group()); 468 JavaValue result(T_VOID); 469 JavaCalls::call_special(&result, thread_oop, 470 klass, 471 vmSymbols::object_initializer_name(), 472 vmSymbols::threadgroup_string_void_signature(), 473 thread_group, 474 string, 475 CHECK); 476 477 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass()); 478 JavaCalls::call_special(&result, 479 thread_group, 480 group, 481 vmSymbols::add_method_name(), 482 vmSymbols::thread_void_signature(), 483 thread_oop, // ARG 1 484 CHECK); 485 486 { MutexLocker mu(Threads_lock); 487 JavaThread* listener_thread = new JavaThread(&attach_listener_thread_entry); 488 489 // Check that thread and osthread were created 490 if (listener_thread == NULL || listener_thread->osthread() == NULL) { 491 vm_exit_during_initialization("java.lang.OutOfMemoryError", 492 "unable to create new native thread"); 493 } 494 495 java_lang_Thread::set_thread(thread_oop(), listener_thread); 496 java_lang_Thread::set_daemon(thread_oop()); 497 498 listener_thread->set_threadObj(thread_oop()); 499 Threads::add(listener_thread); 500 Thread::start(listener_thread); 501 } 502} 503 504// Performs clean-up tasks on platforms where we can detect that the last 505// client has detached 506void AttachListener::detachall() { 507 // call the platform dependent clean-up 508 pd_detachall(); 509} 510