1/* 2 * Copyright (c) 2005, 2017, 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/vmGCOperations.hpp" 29#include "memory/resourceArea.hpp" 30#include "oops/oop.inline.hpp" 31#include "prims/jvmtiExport.hpp" 32#include "runtime/arguments.hpp" 33#include "runtime/globals.hpp" 34#include "runtime/java.hpp" 35#include "runtime/javaCalls.hpp" 36#include "runtime/os.hpp" 37#include "services/attachListener.hpp" 38#include "services/diagnosticCommand.hpp" 39#include "services/heapDumper.hpp" 40#include "services/writeableFlags.hpp" 41#include "utilities/debug.hpp" 42#include "utilities/formatBuffer.hpp" 43 44volatile bool AttachListener::_initialized; 45 46// Implementation of "properties" command. 47// 48// Invokes VMSupport.serializePropertiesToByteArray to serialize 49// the system properties into a byte array. 50 51static InstanceKlass* load_and_initialize_klass(Symbol* sh, TRAPS) { 52 Klass* k = SystemDictionary::resolve_or_fail(sh, true, CHECK_NULL); 53 InstanceKlass* ik = InstanceKlass::cast(k); 54 if (ik->should_be_initialized()) { 55 ik->initialize(CHECK_NULL); 56 } 57 return ik; 58} 59 60static jint get_properties(AttachOperation* op, outputStream* out, Symbol* serializePropertiesMethod) { 61 Thread* THREAD = Thread::current(); 62 HandleMark hm; 63 64 // load VMSupport 65 Symbol* klass = vmSymbols::jdk_internal_vm_VMSupport(); 66 InstanceKlass* k = load_and_initialize_klass(klass, THREAD); 67 if (HAS_PENDING_EXCEPTION) { 68 java_lang_Throwable::print(PENDING_EXCEPTION, out); 69 CLEAR_PENDING_EXCEPTION; 70 return JNI_ERR; 71 } 72 73 // invoke the serializePropertiesToByteArray method 74 JavaValue result(T_OBJECT); 75 JavaCallArguments args; 76 77 78 Symbol* signature = vmSymbols::serializePropertiesToByteArray_signature(); 79 JavaCalls::call_static(&result, 80 k, 81 serializePropertiesMethod, 82 signature, 83 &args, 84 THREAD); 85 if (HAS_PENDING_EXCEPTION) { 86 java_lang_Throwable::print(PENDING_EXCEPTION, out); 87 CLEAR_PENDING_EXCEPTION; 88 return JNI_ERR; 89 } 90 91 // The result should be a [B 92 oop res = (oop)result.get_jobject(); 93 assert(res->is_typeArray(), "just checking"); 94 assert(TypeArrayKlass::cast(res->klass())->element_type() == T_BYTE, "just checking"); 95 96 // copy the bytes to the output stream 97 typeArrayOop ba = typeArrayOop(res); 98 jbyte* addr = typeArrayOop(res)->byte_at_addr(0); 99 out->print_raw((const char*)addr, ba->length()); 100 101 return JNI_OK; 102} 103 104// Implementation of "load" command. 105static jint load_agent(AttachOperation* op, outputStream* out) { 106 // get agent name and options 107 const char* agent = op->arg(0); 108 const char* absParam = op->arg(1); 109 const char* options = op->arg(2); 110 111 // If loading a java agent then need to ensure that the java.instrument module is loaded 112 if (strcmp(agent, "instrument") == 0) { 113 Thread* THREAD = Thread::current(); 114 ResourceMark rm(THREAD); 115 HandleMark hm(THREAD); 116 JavaValue result(T_OBJECT); 117 Handle h_module_name = java_lang_String::create_from_str("java.instrument", THREAD); 118 JavaCalls::call_static(&result, 119 SystemDictionary::module_Modules_klass(), 120 vmSymbols::loadModule_name(), 121 vmSymbols::loadModule_signature(), 122 h_module_name, 123 THREAD); 124 if (HAS_PENDING_EXCEPTION) { 125 java_lang_Throwable::print(PENDING_EXCEPTION, out); 126 CLEAR_PENDING_EXCEPTION; 127 return JNI_ERR; 128 } 129 } 130 131 return JvmtiExport::load_agent_library(agent, absParam, options, out); 132} 133 134// Implementation of "properties" command. 135// See also: PrintSystemPropertiesDCmd class 136static jint get_system_properties(AttachOperation* op, outputStream* out) { 137 return get_properties(op, out, vmSymbols::serializePropertiesToByteArray_name()); 138} 139 140// Implementation of "agent_properties" command. 141static jint get_agent_properties(AttachOperation* op, outputStream* out) { 142 return get_properties(op, out, vmSymbols::serializeAgentPropertiesToByteArray_name()); 143} 144 145// Implementation of "datadump" command. 146// 147// Raises a SIGBREAK signal so that VM dump threads, does deadlock detection, 148// etc. In theory this command should only post a DataDumpRequest to any 149// JVMTI environment that has enabled this event. However it's useful to 150// trigger the SIGBREAK handler. 151 152static jint data_dump(AttachOperation* op, outputStream* out) { 153 if (!ReduceSignalUsage) { 154 AttachListener::pd_data_dump(); 155 } else { 156 if (JvmtiExport::should_post_data_dump()) { 157 JvmtiExport::post_data_dump(); 158 } 159 } 160 return JNI_OK; 161} 162 163// Implementation of "threaddump" command - essentially a remote ctrl-break 164// See also: ThreadDumpDCmd class 165// 166static jint thread_dump(AttachOperation* op, outputStream* out) { 167 bool print_concurrent_locks = false; 168 if (op->arg(0) != NULL && strcmp(op->arg(0), "-l") == 0) { 169 print_concurrent_locks = true; 170 } 171 172 // thread stacks 173 VM_PrintThreads op1(out, print_concurrent_locks); 174 VMThread::execute(&op1); 175 176 // JNI global handles 177 VM_PrintJNI op2(out); 178 VMThread::execute(&op2); 179 180 // Deadlock detection 181 VM_FindDeadlocks op3(out); 182 VMThread::execute(&op3); 183 184 return JNI_OK; 185} 186 187// A jcmd attach operation request was received, which will now 188// dispatch to the diagnostic commands used for serviceability functions. 189static jint jcmd(AttachOperation* op, outputStream* out) { 190 Thread* THREAD = Thread::current(); 191 // All the supplied jcmd arguments are stored as a single 192 // string (op->arg(0)). This is parsed by the Dcmd framework. 193 DCmd::parse_and_execute(DCmd_Source_AttachAPI, out, op->arg(0), ' ', THREAD); 194 if (HAS_PENDING_EXCEPTION) { 195 java_lang_Throwable::print(PENDING_EXCEPTION, out); 196 out->cr(); 197 CLEAR_PENDING_EXCEPTION; 198 return JNI_ERR; 199 } 200 return JNI_OK; 201} 202 203// Implementation of "dumpheap" command. 204// See also: HeapDumpDCmd class 205// 206// Input arguments :- 207// arg0: Name of the dump file 208// arg1: "-live" or "-all" 209jint dump_heap(AttachOperation* op, outputStream* out) { 210 const char* path = op->arg(0); 211 if (path == NULL || path[0] == '\0') { 212 out->print_cr("No dump file specified"); 213 } else { 214 bool live_objects_only = true; // default is true to retain the behavior before this change is made 215 const char* arg1 = op->arg(1); 216 if (arg1 != NULL && (strlen(arg1) > 0)) { 217 if (strcmp(arg1, "-all") != 0 && strcmp(arg1, "-live") != 0) { 218 out->print_cr("Invalid argument to dumpheap operation: %s", arg1); 219 return JNI_ERR; 220 } 221 live_objects_only = strcmp(arg1, "-live") == 0; 222 } 223 224 // Request a full GC before heap dump if live_objects_only = true 225 // This helps reduces the amount of unreachable objects in the dump 226 // and makes it easier to browse. 227 HeapDumper dumper(live_objects_only /* request GC */); 228 int res = dumper.dump(op->arg(0)); 229 if (res == 0) { 230 out->print_cr("Heap dump file created"); 231 } else { 232 // heap dump failed 233 ResourceMark rm; 234 char* error = dumper.error_as_C_string(); 235 if (error == NULL) { 236 out->print_cr("Dump failed - reason unknown"); 237 } else { 238 out->print_cr("%s", error); 239 } 240 } 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" 250static jint heap_inspection(AttachOperation* op, outputStream* out) { 251 bool live_objects_only = true; // default is true to retain the behavior before this change is made 252 const char* arg0 = op->arg(0); 253 if (arg0 != NULL && (strlen(arg0) > 0)) { 254 if (strcmp(arg0, "-all") != 0 && strcmp(arg0, "-live") != 0) { 255 out->print_cr("Invalid argument to inspectheap operation: %s", arg0); 256 return JNI_ERR; 257 } 258 live_objects_only = strcmp(arg0, "-live") == 0; 259 } 260 VM_GC_HeapInspection heapop(out, live_objects_only /* request full gc */); 261 VMThread::execute(&heapop); 262 return JNI_OK; 263} 264 265// Implementation of "setflag" command 266static jint set_flag(AttachOperation* op, outputStream* out) { 267 268 const char* name = NULL; 269 if ((name = op->arg(0)) == NULL) { 270 out->print_cr("flag name is missing"); 271 return JNI_ERR; 272 } 273 274 FormatBuffer<80> err_msg("%s", ""); 275 276 int ret = WriteableFlags::set_flag(op->arg(0), op->arg(1), Flag::ATTACH_ON_DEMAND, err_msg); 277 if (ret != Flag::SUCCESS) { 278 if (ret == Flag::NON_WRITABLE) { 279 // if the flag is not manageable try to change it through 280 // the platform dependent implementation 281 return AttachListener::pd_set_flag(op, out); 282 } else { 283 out->print_cr("%s", err_msg.buffer()); 284 } 285 286 return JNI_ERR; 287 } 288 return JNI_OK; 289} 290 291// Implementation of "printflag" command 292// See also: PrintVMFlagsDCmd class 293static jint print_flag(AttachOperation* op, outputStream* out) { 294 const char* name = NULL; 295 if ((name = op->arg(0)) == NULL) { 296 out->print_cr("flag name is missing"); 297 return JNI_ERR; 298 } 299 Flag* f = Flag::find_flag((char*)name, strlen(name)); 300 if (f) { 301 f->print_as_flag(out); 302 out->cr(); 303 } else { 304 out->print_cr("no such flag '%s'", name); 305 } 306 return JNI_OK; 307} 308 309// Table to map operation names to functions. 310 311// names must be of length <= AttachOperation::name_length_max 312static AttachOperationFunctionInfo funcs[] = { 313 { "agentProperties", get_agent_properties }, 314 { "datadump", data_dump }, 315 { "dumpheap", dump_heap }, 316 { "load", load_agent }, 317 { "properties", get_system_properties }, 318 { "threaddump", thread_dump }, 319 { "inspectheap", heap_inspection }, 320 { "setflag", set_flag }, 321 { "printflag", print_flag }, 322 { "jcmd", jcmd }, 323 { NULL, NULL } 324}; 325 326 327 328// The Attach Listener threads services a queue. It dequeues an operation 329// from the queue, examines the operation name (command), and dispatches 330// to the corresponding function to perform the operation. 331 332static void attach_listener_thread_entry(JavaThread* thread, TRAPS) { 333 os::set_priority(thread, NearMaxPriority); 334 335 thread->record_stack_base_and_size(); 336 337 if (AttachListener::pd_init() != 0) { 338 return; 339 } 340 AttachListener::set_initialized(); 341 342 for (;;) { 343 AttachOperation* op = AttachListener::dequeue(); 344 if (op == NULL) { 345 return; // dequeue failed or shutdown 346 } 347 348 ResourceMark rm; 349 bufferedStream st; 350 jint res = JNI_OK; 351 352 // handle special detachall operation 353 if (strcmp(op->name(), AttachOperation::detachall_operation_name()) == 0) { 354 AttachListener::detachall(); 355 } else if (!EnableDynamicAgentLoading && strcmp(op->name(), "load") == 0) { 356 st.print("Dynamic agent loading is not enabled. " 357 "Use -XX:+EnableDynamicAgentLoading to launch target VM."); 358 res = JNI_ERR; 359 } else { 360 // find the function to dispatch too 361 AttachOperationFunctionInfo* info = NULL; 362 for (int i=0; funcs[i].name != NULL; i++) { 363 const char* name = funcs[i].name; 364 assert(strlen(name) <= AttachOperation::name_length_max, "operation <= name_length_max"); 365 if (strcmp(op->name(), name) == 0) { 366 info = &(funcs[i]); 367 break; 368 } 369 } 370 371 // check for platform dependent attach operation 372 if (info == NULL) { 373 info = AttachListener::pd_find_operation(op->name()); 374 } 375 376 if (info != NULL) { 377 // dispatch to the function that implements this operation 378 res = (info->func)(op, &st); 379 } else { 380 st.print("Operation %s not recognized!", op->name()); 381 res = JNI_ERR; 382 } 383 } 384 385 // operation complete - send result and output to client 386 op->complete(res, &st); 387 } 388} 389 390bool AttachListener::has_init_error(TRAPS) { 391 if (HAS_PENDING_EXCEPTION) { 392 tty->print_cr("Exception in VM (AttachListener::init) : "); 393 java_lang_Throwable::print(PENDING_EXCEPTION, tty); 394 tty->cr(); 395 396 CLEAR_PENDING_EXCEPTION; 397 398 return true; 399 } else { 400 return false; 401 } 402} 403 404// Starts the Attach Listener thread 405void AttachListener::init() { 406 EXCEPTION_MARK; 407 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, THREAD); 408 if (has_init_error(THREAD)) { 409 return; 410 } 411 412 InstanceKlass* klass = InstanceKlass::cast(k); 413 instanceHandle thread_oop = klass->allocate_instance_handle(THREAD); 414 if (has_init_error(THREAD)) { 415 return; 416 } 417 418 const char thread_name[] = "Attach Listener"; 419 Handle string = java_lang_String::create_from_str(thread_name, THREAD); 420 if (has_init_error(THREAD)) { 421 return; 422 } 423 424 // Initialize thread_oop to put it into the system threadGroup 425 Handle thread_group (THREAD, Universe::system_thread_group()); 426 JavaValue result(T_VOID); 427 JavaCalls::call_special(&result, thread_oop, 428 klass, 429 vmSymbols::object_initializer_name(), 430 vmSymbols::threadgroup_string_void_signature(), 431 thread_group, 432 string, 433 THREAD); 434 435 if (has_init_error(THREAD)) { 436 return; 437 } 438 439 Klass* group = SystemDictionary::ThreadGroup_klass(); 440 JavaCalls::call_special(&result, 441 thread_group, 442 group, 443 vmSymbols::add_method_name(), 444 vmSymbols::thread_void_signature(), 445 thread_oop, // ARG 1 446 THREAD); 447 if (has_init_error(THREAD)) { 448 return; 449 } 450 451 { MutexLocker mu(Threads_lock); 452 JavaThread* listener_thread = new JavaThread(&attach_listener_thread_entry); 453 454 // Check that thread and osthread were created 455 if (listener_thread == NULL || listener_thread->osthread() == NULL) { 456 vm_exit_during_initialization("java.lang.OutOfMemoryError", 457 os::native_thread_creation_failed_msg()); 458 } 459 460 java_lang_Thread::set_thread(thread_oop(), listener_thread); 461 java_lang_Thread::set_daemon(thread_oop()); 462 463 listener_thread->set_threadObj(thread_oop()); 464 Threads::add(listener_thread); 465 Thread::start(listener_thread); 466 } 467} 468 469// Performs clean-up tasks on platforms where we can detect that the last 470// client has detached 471void AttachListener::detachall() { 472 // call the platform dependent clean-up 473 pd_detachall(); 474} 475