1 /* 2 * Copyright (c) 2005, 2020, 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/gcVMOperations.hpp" 29 #include "memory/resourceArea.hpp" 30 #include "memory/universe.hpp" 31 #include "oops/oop.inline.hpp" 32 #include "oops/typeArrayOop.inline.hpp" 33 #include "prims/jvmtiExport.hpp" 34 #include "runtime/arguments.hpp" 35 #include "runtime/flags/jvmFlag.hpp" 36 #include "runtime/globals.hpp" 37 #include "runtime/handles.inline.hpp" 38 #include "runtime/java.hpp" 39 #include "runtime/javaCalls.hpp" 40 #include "runtime/os.hpp" 41 #include "services/attachListener.hpp" 42 #include "services/diagnosticCommand.hpp" 43 #include "services/heapDumper.hpp" 44 #include "services/writeableFlags.hpp" 45 #include "utilities/debug.hpp" 46 #include "utilities/formatBuffer.hpp" 47 48 volatile AttachListenerState AttachListener::_state = AL_NOT_INITIALIZED; 49 50 // Implementation of "properties" command. 51 // 52 // Invokes VMSupport.serializePropertiesToByteArray to serialize 53 // the system properties into a byte array. 54 55 static InstanceKlass* load_and_initialize_klass(Symbol* sh, TRAPS) { 56 Klass* k = SystemDictionary::resolve_or_fail(sh, true, CHECK_NULL); 57 InstanceKlass* ik = InstanceKlass::cast(k); 58 if (ik->should_be_initialized()) { 59 ik->initialize(CHECK_NULL); 60 } 61 return ik; 62 } 63 64 static jint get_properties(AttachOperation* op, outputStream* out, Symbol* serializePropertiesMethod) { 65 Thread* THREAD = Thread::current(); 66 HandleMark hm; 67 68 // load VMSupport 69 Symbol* klass = vmSymbols::jdk_internal_vm_VMSupport(); 70 InstanceKlass* k = load_and_initialize_klass(klass, THREAD); 71 if (HAS_PENDING_EXCEPTION) { 72 java_lang_Throwable::print(PENDING_EXCEPTION, out); 73 CLEAR_PENDING_EXCEPTION; 74 return JNI_ERR; 75 } 76 77 // invoke the serializePropertiesToByteArray method 78 JavaValue result(T_OBJECT); 79 JavaCallArguments args; 80 81 82 Symbol* signature = vmSymbols::serializePropertiesToByteArray_signature(); 83 JavaCalls::call_static(&result, 84 k, 85 serializePropertiesMethod, 86 signature, 87 &args, 88 THREAD); 89 if (HAS_PENDING_EXCEPTION) { 90 java_lang_Throwable::print(PENDING_EXCEPTION, out); 91 CLEAR_PENDING_EXCEPTION; 92 return JNI_ERR; 93 } 94 95 // The result should be a [B 96 oop res = (oop)result.get_jobject(); 97 assert(res->is_typeArray(), "just checking"); 98 assert(TypeArrayKlass::cast(res->klass())->element_type() == T_BYTE, "just checking"); 99 100 // copy the bytes to the output stream 101 typeArrayOop ba = typeArrayOop(res); 102 jbyte* addr = typeArrayOop(res)->byte_at_addr(0); 103 out->print_raw((const char*)addr, ba->length()); 104 105 return JNI_OK; 106 } 107 108 // Implementation of "load" command. 109 static jint load_agent(AttachOperation* op, outputStream* out) { 110 // get agent name and options 111 const char* agent = op->arg(0); 112 const char* absParam = op->arg(1); 113 const char* options = op->arg(2); 114 115 // If loading a java agent then need to ensure that the java.instrument module is loaded 116 if (strcmp(agent, "instrument") == 0) { 117 Thread* THREAD = Thread::current(); 118 ResourceMark rm(THREAD); 119 HandleMark hm(THREAD); 120 JavaValue result(T_OBJECT); 121 Handle h_module_name = java_lang_String::create_from_str("java.instrument", THREAD); 122 JavaCalls::call_static(&result, 123 SystemDictionary::module_Modules_klass(), 124 vmSymbols::loadModule_name(), 125 vmSymbols::loadModule_signature(), 126 h_module_name, 127 THREAD); 128 if (HAS_PENDING_EXCEPTION) { 129 java_lang_Throwable::print(PENDING_EXCEPTION, out); 130 CLEAR_PENDING_EXCEPTION; 131 return JNI_ERR; 132 } 133 } 134 135 return JvmtiExport::load_agent_library(agent, absParam, options, out); 136 } 137 138 // Implementation of "properties" command. 139 // See also: PrintSystemPropertiesDCmd class 140 static jint get_system_properties(AttachOperation* op, outputStream* out) { 141 return get_properties(op, out, vmSymbols::serializePropertiesToByteArray_name()); 142 } 143 144 // Implementation of "agent_properties" command. 145 static jint get_agent_properties(AttachOperation* op, outputStream* out) { 146 return get_properties(op, out, vmSymbols::serializeAgentPropertiesToByteArray_name()); 147 } 148 149 // Implementation of "datadump" command. 150 // 151 // Raises a SIGBREAK signal so that VM dump threads, does deadlock detection, 152 // etc. In theory this command should only post a DataDumpRequest to any 153 // JVMTI environment that has enabled this event. However it's useful to 154 // trigger the SIGBREAK handler. 155 156 static jint data_dump(AttachOperation* op, outputStream* out) { 157 if (!ReduceSignalUsage) { 158 AttachListener::pd_data_dump(); 159 } else { 160 if (JvmtiExport::should_post_data_dump()) { 161 JvmtiExport::post_data_dump(); 162 } 163 } 164 return JNI_OK; 165 } 166 167 // Implementation of "threaddump" command - essentially a remote ctrl-break 168 // See also: ThreadDumpDCmd class 169 // 170 static jint thread_dump(AttachOperation* op, outputStream* out) { 171 bool print_concurrent_locks = false; 172 bool print_extended_info = false; 173 if (op->arg(0) != NULL) { 174 for (int i = 0; op->arg(0)[i] != 0; ++i) { 175 if (op->arg(0)[i] == 'l') { 176 print_concurrent_locks = true; 177 } 178 if (op->arg(0)[i] == 'e') { 179 print_extended_info = true; 180 } 181 } 182 } 183 184 // thread stacks 185 VM_PrintThreads op1(out, print_concurrent_locks, print_extended_info); 186 VMThread::execute(&op1); 187 188 // JNI global handles 189 VM_PrintJNI op2(out); 190 VMThread::execute(&op2); 191 192 // Deadlock detection 193 VM_FindDeadlocks op3(out); 194 VMThread::execute(&op3); 195 196 return JNI_OK; 197 } 198 199 // A jcmd attach operation request was received, which will now 200 // dispatch to the diagnostic commands used for serviceability functions. 201 static jint jcmd(AttachOperation* op, outputStream* out) { 202 Thread* THREAD = Thread::current(); 203 // All the supplied jcmd arguments are stored as a single 204 // string (op->arg(0)). This is parsed by the Dcmd framework. 205 DCmd::parse_and_execute(DCmd_Source_AttachAPI, out, op->arg(0), ' ', THREAD); 206 if (HAS_PENDING_EXCEPTION) { 207 java_lang_Throwable::print(PENDING_EXCEPTION, out); 208 out->cr(); 209 CLEAR_PENDING_EXCEPTION; 210 return JNI_ERR; 211 } 212 return JNI_OK; 213 } 214 215 // Implementation of "dumpheap" command. 216 // See also: HeapDumpDCmd class 217 // 218 // Input arguments :- 219 // arg0: Name of the dump file 220 // arg1: "-live" or "-all" 221 jint dump_heap(AttachOperation* op, outputStream* out) { 222 const char* path = op->arg(0); 223 if (path == NULL || path[0] == '\0') { 224 out->print_cr("No dump file specified"); 225 } else { 226 bool live_objects_only = true; // default is true to retain the behavior before this change is made 227 const char* arg1 = op->arg(1); 228 if (arg1 != NULL && (strlen(arg1) > 0)) { 229 if (strcmp(arg1, "-all") != 0 && strcmp(arg1, "-live") != 0) { 230 out->print_cr("Invalid argument to dumpheap operation: %s", arg1); 231 return JNI_ERR; 232 } 233 live_objects_only = strcmp(arg1, "-live") == 0; 234 } 235 236 // Request a full GC before heap dump if live_objects_only = true 237 // This helps reduces the amount of unreachable objects in the dump 238 // and makes it easier to browse. 239 HeapDumper dumper(live_objects_only /* request GC */); 240 dumper.dump(op->arg(0), out); 241 } 242 return JNI_OK; 243 } 244 245 // Implementation of "inspectheap" command 246 // See also: ClassHistogramDCmd class 247 // 248 // Input arguments :- 249 // arg0: "-live" or "-all" 250 // arg1: Name of the dump file or NULL 251 static jint heap_inspection(AttachOperation* op, outputStream* out) { 252 bool live_objects_only = true; // default is true to retain the behavior before this change is made 253 outputStream* os = out; // if path not specified or path is NULL, use out 254 fileStream* fs = NULL; 255 const char* arg0 = op->arg(0); 256 if (arg0 != NULL && (strlen(arg0) > 0)) { 257 if (strcmp(arg0, "-all") != 0 && strcmp(arg0, "-live") != 0) { 258 out->print_cr("Invalid argument to inspectheap operation: %s", arg0); 259 return JNI_ERR; 260 } 261 live_objects_only = strcmp(arg0, "-live") == 0; 262 } 263 264 const char* path = op->arg(1); 265 if (path != NULL) { 266 if (path[0] == '\0') { 267 out->print_cr("No dump file specified"); 268 } else { 269 // create file 270 fs = new (ResourceObj::C_HEAP, mtInternal) fileStream(path); 271 if (fs == NULL) { 272 out->print_cr("Failed to allocate space for file: %s", path); 273 return JNI_ERR; 274 } 275 os = fs; 276 } 277 } 278 279 VM_GC_HeapInspection heapop(os, live_objects_only /* request full gc */); 280 VMThread::execute(&heapop); 281 if (os != NULL && os != out) { 282 out->print_cr("Heap inspection file created: %s", path); 283 delete fs; 284 } 285 return JNI_OK; 286 } 287 288 // Implementation of "setflag" command 289 static jint set_flag(AttachOperation* op, outputStream* out) { 290 291 const char* name = NULL; 292 if ((name = op->arg(0)) == NULL) { 293 out->print_cr("flag name is missing"); 294 return JNI_ERR; 295 } 296 297 FormatBuffer<80> err_msg("%s", ""); 298 299 int ret = WriteableFlags::set_flag(op->arg(0), op->arg(1), JVMFlag::ATTACH_ON_DEMAND, err_msg); 300 if (ret != JVMFlag::SUCCESS) { 301 if (ret == JVMFlag::NON_WRITABLE) { 302 // if the flag is not manageable try to change it through 303 // the platform dependent implementation 304 return AttachListener::pd_set_flag(op, out); 305 } else { 306 out->print_cr("%s", err_msg.buffer()); 307 } 308 309 return JNI_ERR; 310 } 311 return JNI_OK; 312 } 313 314 // Implementation of "printflag" command 315 // See also: PrintVMFlagsDCmd class 316 static jint print_flag(AttachOperation* op, outputStream* out) { 317 const char* name = NULL; 318 if ((name = op->arg(0)) == NULL) { 319 out->print_cr("flag name is missing"); 320 return JNI_ERR; 321 } 322 JVMFlag* f = JVMFlag::find_flag(name); 323 if (f) { 324 f->print_as_flag(out); 325 out->cr(); 326 } else { 327 out->print_cr("no such flag '%s'", name); 328 } 329 return JNI_OK; 330 } 331 332 // Table to map operation names to functions. 333 334 // names must be of length <= AttachOperation::name_length_max 335 static AttachOperationFunctionInfo funcs[] = { 336 { "agentProperties", get_agent_properties }, 337 { "datadump", data_dump }, 338 { "dumpheap", dump_heap }, 339 { "load", load_agent }, 340 { "properties", get_system_properties }, 341 { "threaddump", thread_dump }, 342 { "inspectheap", heap_inspection }, 343 { "setflag", set_flag }, 344 { "printflag", print_flag }, 345 { "jcmd", jcmd }, 346 { NULL, NULL } 347 }; 348 349 350 351 // The Attach Listener threads services a queue. It dequeues an operation 352 // from the queue, examines the operation name (command), and dispatches 353 // to the corresponding function to perform the operation. 354 355 static void attach_listener_thread_entry(JavaThread* thread, TRAPS) { 356 os::set_priority(thread, NearMaxPriority); 357 358 assert(thread == Thread::current(), "Must be"); 359 assert(thread->stack_base() != NULL && thread->stack_size() > 0, 360 "Should already be setup"); 361 362 if (AttachListener::pd_init() != 0) { 363 AttachListener::set_state(AL_NOT_INITIALIZED); 364 return; 365 } 366 AttachListener::set_initialized(); 367 368 for (;;) { 369 AttachOperation* op = AttachListener::dequeue(); 370 if (op == NULL) { 371 AttachListener::set_state(AL_NOT_INITIALIZED); 372 return; // dequeue failed or shutdown 373 } 374 375 ResourceMark rm; 376 bufferedStream st; 377 jint res = JNI_OK; 378 379 // handle special detachall operation 380 if (strcmp(op->name(), AttachOperation::detachall_operation_name()) == 0) { 381 AttachListener::detachall(); 382 } else if (!EnableDynamicAgentLoading && strcmp(op->name(), "load") == 0) { 383 st.print("Dynamic agent loading is not enabled. " 384 "Use -XX:+EnableDynamicAgentLoading to launch target VM."); 385 res = JNI_ERR; 386 } else { 387 // find the function to dispatch too 388 AttachOperationFunctionInfo* info = NULL; 389 for (int i=0; funcs[i].name != NULL; i++) { 390 const char* name = funcs[i].name; 391 assert(strlen(name) <= AttachOperation::name_length_max, "operation <= name_length_max"); 392 if (strcmp(op->name(), name) == 0) { 393 info = &(funcs[i]); 394 break; 395 } 396 } 397 398 // check for platform dependent attach operation 399 if (info == NULL) { 400 info = AttachListener::pd_find_operation(op->name()); 401 } 402 403 if (info != NULL) { 404 // dispatch to the function that implements this operation 405 res = (info->func)(op, &st); 406 } else { 407 st.print("Operation %s not recognized!", op->name()); 408 res = JNI_ERR; 409 } 410 } 411 412 // operation complete - send result and output to client 413 op->complete(res, &st); 414 } 415 416 ShouldNotReachHere(); 417 } 418 419 bool AttachListener::has_init_error(TRAPS) { 420 if (HAS_PENDING_EXCEPTION) { 421 tty->print_cr("Exception in VM (AttachListener::init) : "); 422 java_lang_Throwable::print(PENDING_EXCEPTION, tty); 423 tty->cr(); 424 425 CLEAR_PENDING_EXCEPTION; 426 427 return true; 428 } else { 429 return false; 430 } 431 } 432 433 // Starts the Attach Listener thread 434 void AttachListener::init() { 435 EXCEPTION_MARK; 436 437 const char thread_name[] = "Attach Listener"; 438 Handle string = java_lang_String::create_from_str(thread_name, THREAD); 439 if (has_init_error(THREAD)) { 440 set_state(AL_NOT_INITIALIZED); 441 return; 442 } 443 444 // Initialize thread_oop to put it into the system threadGroup 445 Handle thread_group (THREAD, Universe::system_thread_group()); 446 Handle thread_oop = JavaCalls::construct_new_instance(SystemDictionary::Thread_klass(), 447 vmSymbols::threadgroup_string_void_signature(), 448 thread_group, 449 string, 450 THREAD); 451 if (has_init_error(THREAD)) { 452 set_state(AL_NOT_INITIALIZED); 453 return; 454 } 455 456 Klass* group = SystemDictionary::ThreadGroup_klass(); 457 JavaValue result(T_VOID); 458 JavaCalls::call_special(&result, 459 thread_group, 460 group, 461 vmSymbols::add_method_name(), 462 vmSymbols::thread_void_signature(), 463 thread_oop, 464 THREAD); 465 if (has_init_error(THREAD)) { 466 set_state(AL_NOT_INITIALIZED); 467 return; 468 } 469 470 { MutexLocker mu(THREAD, Threads_lock); 471 JavaThread* listener_thread = new JavaThread(&attach_listener_thread_entry); 472 473 // Check that thread and osthread were created 474 if (listener_thread == NULL || listener_thread->osthread() == NULL) { 475 vm_exit_during_initialization("java.lang.OutOfMemoryError", 476 os::native_thread_creation_failed_msg()); 477 } 478 479 java_lang_Thread::set_thread(thread_oop(), listener_thread); 480 java_lang_Thread::set_daemon(thread_oop()); 481 482 listener_thread->set_threadObj(thread_oop()); 483 Threads::add(listener_thread); 484 Thread::start(listener_thread); 485 } 486 } 487 488 // Performs clean-up tasks on platforms where we can detect that the last 489 // client has detached 490 void AttachListener::detachall() { 491 // call the platform dependent clean-up 492 pd_detachall(); 493 }