1 /* 2 * Copyright (c) 2005, 2015, 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 42 volatile bool AttachListener::_initialized; 43 44 // Implementation of "properties" command. 45 // 46 // Invokes VMSupport.serializePropertiesToByteArray to serialize 47 // the system properties into a byte array. 48 49 static InstanceKlass* load_and_initialize_klass(Symbol* sh, TRAPS) { 50 Klass* k = SystemDictionary::resolve_or_fail(sh, true, CHECK_NULL); 51 InstanceKlass* ik = InstanceKlass::cast(k); 52 if (ik->should_be_initialized()) { 53 ik->initialize(CHECK_NULL); 54 } 55 return ik; 56 } 57 58 static jint get_properties(AttachOperation* op, outputStream* out, Symbol* serializePropertiesMethod) { 59 Thread* THREAD = Thread::current(); 60 HandleMark hm; 61 62 // load VMSupport 63 Symbol* klass = vmSymbols::jdk_internal_vm_VMSupport(); 64 InstanceKlass* k = load_and_initialize_klass(klass, THREAD); 65 if (HAS_PENDING_EXCEPTION) { 66 java_lang_Throwable::print(PENDING_EXCEPTION, out); 67 CLEAR_PENDING_EXCEPTION; 68 return JNI_ERR; 69 } 70 71 // invoke the serializePropertiesToByteArray method 72 JavaValue result(T_OBJECT); 73 JavaCallArguments args; 74 75 76 Symbol* signature = vmSymbols::serializePropertiesToByteArray_signature(); 77 JavaCalls::call_static(&result, 78 k, 79 serializePropertiesMethod, 80 signature, 81 &args, 82 THREAD); 83 if (HAS_PENDING_EXCEPTION) { 84 java_lang_Throwable::print(PENDING_EXCEPTION, out); 85 CLEAR_PENDING_EXCEPTION; 86 return JNI_ERR; 87 } 88 89 // The result should be a [B 90 oop res = (oop)result.get_jobject(); 91 assert(res->is_typeArray(), "just checking"); 92 assert(TypeArrayKlass::cast(res->klass())->element_type() == T_BYTE, "just checking"); 93 94 // copy the bytes to the output stream 95 typeArrayOop ba = typeArrayOop(res); 96 jbyte* addr = typeArrayOop(res)->byte_at_addr(0); 97 out->print_raw((const char*)addr, ba->length()); 98 99 return JNI_OK; 100 } 101 102 // Implementation of "properties" command. 103 // See also: PrintSystemPropertiesDCmd class 104 static jint get_system_properties(AttachOperation* op, outputStream* out) { 105 return get_properties(op, out, vmSymbols::serializePropertiesToByteArray_name()); 106 } 107 108 // Implementation of "agent_properties" command. 109 static jint get_agent_properties(AttachOperation* op, outputStream* out) { 110 return get_properties(op, out, vmSymbols::serializeAgentPropertiesToByteArray_name()); 111 } 112 113 // Implementation of "datadump" command. 114 // 115 // Raises a SIGBREAK signal so that VM dump threads, does deadlock detection, 116 // etc. In theory this command should only post a DataDumpRequest to any 117 // JVMTI environment that has enabled this event. However it's useful to 118 // trigger the SIGBREAK handler. 119 120 static jint data_dump(AttachOperation* op, outputStream* out) { 121 if (!ReduceSignalUsage) { 122 AttachListener::pd_data_dump(); 123 } else { 124 if (JvmtiExport::should_post_data_dump()) { 125 JvmtiExport::post_data_dump(); 126 } 127 } 128 return JNI_OK; 129 } 130 131 // Implementation of "threaddump" command - essentially a remote ctrl-break 132 // See also: ThreadDumpDCmd class 133 // 134 static jint thread_dump(AttachOperation* op, outputStream* out) { 135 bool print_concurrent_locks = false; 136 if (op->arg(0) != NULL && strcmp(op->arg(0), "-l") == 0) { 137 print_concurrent_locks = true; 138 } 139 140 // thread stacks 141 VM_PrintThreads op1(out, print_concurrent_locks); 142 VMThread::execute(&op1); 143 144 // JNI global handles 145 VM_PrintJNI op2(out); 146 VMThread::execute(&op2); 147 148 // Deadlock detection 149 VM_FindDeadlocks op3(out); 150 VMThread::execute(&op3); 151 152 return JNI_OK; 153 } 154 155 // A jcmd attach operation request was received, which will now 156 // dispatch to the diagnostic commands used for serviceability functions. 157 static jint jcmd(AttachOperation* op, outputStream* out) { 158 Thread* THREAD = Thread::current(); 159 // All the supplied jcmd arguments are stored as a single 160 // string (op->arg(0)). This is parsed by the Dcmd framework. 161 DCmd::parse_and_execute(DCmd_Source_AttachAPI, out, op->arg(0), ' ', THREAD); 162 if (HAS_PENDING_EXCEPTION) { 163 java_lang_Throwable::print(PENDING_EXCEPTION, out); 164 out->cr(); 165 CLEAR_PENDING_EXCEPTION; 166 return JNI_ERR; 167 } 168 return JNI_OK; 169 } 170 171 // Implementation of "dumpheap" command. 172 // See also: HeapDumpDCmd class 173 // 174 // Input arguments :- 175 // arg0: Name of the dump file 176 // arg1: "-live" or "-all" 177 jint dump_heap(AttachOperation* op, outputStream* out) { 178 const char* path = op->arg(0); 179 if (path == NULL || path[0] == '\0') { 180 out->print_cr("No dump file specified"); 181 } else { 182 bool live_objects_only = true; // default is true to retain the behavior before this change is made 183 const char* arg1 = op->arg(1); 184 if (arg1 != NULL && (strlen(arg1) > 0)) { 185 if (strcmp(arg1, "-all") != 0 && strcmp(arg1, "-live") != 0) { 186 out->print_cr("Invalid argument to dumpheap operation: %s", arg1); 187 return JNI_ERR; 188 } 189 live_objects_only = strcmp(arg1, "-live") == 0; 190 } 191 192 // Request a full GC before heap dump if live_objects_only = true 193 // This helps reduces the amount of unreachable objects in the dump 194 // and makes it easier to browse. 195 HeapDumper dumper(live_objects_only /* request GC */); 196 int res = dumper.dump(op->arg(0)); 197 if (res == 0) { 198 out->print_cr("Heap dump file created"); 199 } else { 200 // heap dump failed 201 ResourceMark rm; 202 char* error = dumper.error_as_C_string(); 203 if (error == NULL) { 204 out->print_cr("Dump failed - reason unknown"); 205 } else { 206 out->print_cr("%s", error); 207 } 208 } 209 } 210 return JNI_OK; 211 } 212 213 // Implementation of "inspectheap" command 214 // See also: ClassHistogramDCmd class 215 // 216 // Input arguments :- 217 // arg0: "-live" or "-all" 218 static jint heap_inspection(AttachOperation* op, outputStream* out) { 219 bool live_objects_only = true; // default is true to retain the behavior before this change is made 220 const char* arg0 = op->arg(0); 221 if (arg0 != NULL && (strlen(arg0) > 0)) { 222 if (strcmp(arg0, "-all") != 0 && strcmp(arg0, "-live") != 0) { 223 out->print_cr("Invalid argument to inspectheap operation: %s", arg0); 224 return JNI_ERR; 225 } 226 live_objects_only = strcmp(arg0, "-live") == 0; 227 } 228 VM_GC_HeapInspection heapop(out, live_objects_only /* request full gc */); 229 VMThread::execute(&heapop); 230 return JNI_OK; 231 } 232 233 // Implementation of "setflag" command 234 static jint set_flag(AttachOperation* op, outputStream* out) { 235 236 const char* name = NULL; 237 if ((name = op->arg(0)) == NULL) { 238 out->print_cr("flag name is missing"); 239 return JNI_ERR; 240 } 241 242 FormatBuffer<80> err_msg("%s", ""); 243 244 int ret = WriteableFlags::set_flag(op->arg(0), op->arg(1), Flag::ATTACH_ON_DEMAND, err_msg); 245 if (ret != Flag::SUCCESS) { 246 if (ret == Flag::NON_WRITABLE) { 247 // if the flag is not manageable try to change it through 248 // the platform dependent implementation 249 return AttachListener::pd_set_flag(op, out); 250 } else { 251 out->print_cr("%s", err_msg.buffer()); 252 } 253 254 return JNI_ERR; 255 } 256 return JNI_OK; 257 } 258 259 // Implementation of "printflag" command 260 // See also: PrintVMFlagsDCmd class 261 static jint print_flag(AttachOperation* op, outputStream* out) { 262 const char* name = NULL; 263 if ((name = op->arg(0)) == NULL) { 264 out->print_cr("flag name is missing"); 265 return JNI_ERR; 266 } 267 Flag* f = Flag::find_flag((char*)name, strlen(name)); 268 if (f) { 269 f->print_as_flag(out); 270 out->cr(); 271 } else { 272 out->print_cr("no such flag '%s'", name); 273 } 274 return JNI_OK; 275 } 276 277 // Table to map operation names to functions. 278 279 // names must be of length <= AttachOperation::name_length_max 280 static AttachOperationFunctionInfo funcs[] = { 281 { "agentProperties", get_agent_properties }, 282 { "datadump", data_dump }, 283 { "dumpheap", dump_heap }, 284 { "load", JvmtiExport::load_agent_library }, 285 { "properties", get_system_properties }, 286 { "threaddump", thread_dump }, 287 { "inspectheap", heap_inspection }, 288 { "setflag", set_flag }, 289 { "printflag", print_flag }, 290 { "jcmd", jcmd }, 291 { NULL, NULL } 292 }; 293 294 295 296 // The Attach Listener threads services a queue. It dequeues an operation 297 // from the queue, examines the operation name (command), and dispatches 298 // to the corresponding function to perform the operation. 299 300 static void attach_listener_thread_entry(JavaThread* thread, TRAPS) { 301 os::set_priority(thread, NearMaxPriority); 302 303 thread->record_stack_base_and_size(); 304 305 if (AttachListener::pd_init() != 0) { 306 return; 307 } 308 AttachListener::set_initialized(); 309 310 for (;;) { 311 AttachOperation* op = AttachListener::dequeue(); 312 if (op == NULL) { 313 return; // dequeue failed or shutdown 314 } 315 316 ResourceMark rm; 317 bufferedStream st; 318 jint res = JNI_OK; 319 320 // handle special detachall operation 321 if (strcmp(op->name(), AttachOperation::detachall_operation_name()) == 0) { 322 AttachListener::detachall(); 323 } else { 324 // find the function to dispatch too 325 AttachOperationFunctionInfo* info = NULL; 326 for (int i=0; funcs[i].name != NULL; i++) { 327 const char* name = funcs[i].name; 328 assert(strlen(name) <= AttachOperation::name_length_max, "operation <= name_length_max"); 329 if (strcmp(op->name(), name) == 0) { 330 info = &(funcs[i]); 331 break; 332 } 333 } 334 335 // check for platform dependent attach operation 336 if (info == NULL) { 337 info = AttachListener::pd_find_operation(op->name()); 338 } 339 340 if (info != NULL) { 341 // dispatch to the function that implements this operation 342 res = (info->func)(op, &st); 343 } else { 344 st.print("Operation %s not recognized!", op->name()); 345 res = JNI_ERR; 346 } 347 } 348 349 // operation complete - send result and output to client 350 op->complete(res, &st); 351 } 352 } 353 354 bool AttachListener::has_init_error(TRAPS) { 355 if (HAS_PENDING_EXCEPTION) { 356 tty->print_cr("Exception in VM (AttachListener::init) : "); 357 java_lang_Throwable::print(PENDING_EXCEPTION, tty); 358 tty->cr(); 359 360 CLEAR_PENDING_EXCEPTION; 361 362 return true; 363 } else { 364 return false; 365 } 366 } 367 368 // Starts the Attach Listener thread 369 void AttachListener::init() { 370 EXCEPTION_MARK; 371 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, THREAD); 372 if (has_init_error(THREAD)) { 373 return; 374 } 375 376 InstanceKlass* klass = InstanceKlass::cast(k); 377 instanceHandle thread_oop = klass->allocate_instance_handle(THREAD); 378 if (has_init_error(THREAD)) { 379 return; 380 } 381 382 const char thread_name[] = "Attach Listener"; 383 Handle string = java_lang_String::create_from_str(thread_name, THREAD); 384 if (has_init_error(THREAD)) { 385 return; 386 } 387 388 // Initialize thread_oop to put it into the system threadGroup 389 Handle thread_group (THREAD, Universe::system_thread_group()); 390 JavaValue result(T_VOID); 391 JavaCalls::call_special(&result, thread_oop, 392 klass, 393 vmSymbols::object_initializer_name(), 394 vmSymbols::threadgroup_string_void_signature(), 395 thread_group, 396 string, 397 THREAD); 398 399 if (has_init_error(THREAD)) { 400 return; 401 } 402 403 Klass* group = SystemDictionary::ThreadGroup_klass(); 404 JavaCalls::call_special(&result, 405 thread_group, 406 group, 407 vmSymbols::add_method_name(), 408 vmSymbols::thread_void_signature(), 409 thread_oop, // ARG 1 410 THREAD); 411 if (has_init_error(THREAD)) { 412 return; 413 } 414 415 { MutexLocker mu(Threads_lock); 416 JavaThread* listener_thread = new JavaThread(&attach_listener_thread_entry); 417 418 // Check that thread and osthread were created 419 if (listener_thread == NULL || listener_thread->osthread() == NULL) { 420 vm_exit_during_initialization("java.lang.OutOfMemoryError", 421 os::native_thread_creation_failed_msg()); 422 } 423 424 java_lang_Thread::set_thread(thread_oop(), listener_thread); 425 java_lang_Thread::set_daemon(thread_oop()); 426 427 listener_thread->set_threadObj(thread_oop()); 428 Threads::add(listener_thread); 429 Thread::start(listener_thread); 430 } 431 } 432 433 // Performs clean-up tasks on platforms where we can detect that the last 434 // client has detached 435 void AttachListener::detachall() { 436 // call the platform dependent clean-up 437 pd_detachall(); 438 } --- EOF ---