1 /*
   2  * Copyright (c) 2005, 2012, 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 Klass* load_and_initialize_klass(Symbol* sh, TRAPS) {
  48   Klass* 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   Klass* 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(DCmd_Source_AttachAPI, 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"
 180 jint 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"
 222 static 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
 238 static 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
 258 static 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
 277 static 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
 296 static 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
 315 static 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
 332 static 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
 363 static 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
 382 static 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 
 404 static void attach_listener_thread_entry(JavaThread* thread, TRAPS) {
 405   os::set_priority(thread, NearMaxPriority);
 406 
 407   thread->record_stack_base_and_size();
 408 
 409   if (AttachListener::pd_init() != 0) {
 410     return;
 411   }
 412   AttachListener::set_initialized();
 413 
 414   for (;;) {
 415     AttachOperation* op = AttachListener::dequeue();
 416     if (op == NULL) {
 417       return;   // dequeue failed or shutdown
 418     }
 419 
 420     ResourceMark rm;
 421     bufferedStream st;
 422     jint res = JNI_OK;
 423 
 424     // handle special detachall operation
 425     if (strcmp(op->name(), AttachOperation::detachall_operation_name()) == 0) {
 426       AttachListener::detachall();
 427     } else {
 428       // find the function to dispatch too
 429       AttachOperationFunctionInfo* info = NULL;
 430       for (int i=0; funcs[i].name != NULL; i++) {
 431         const char* name = funcs[i].name;
 432         assert(strlen(name) <= AttachOperation::name_length_max, "operation <= name_length_max");
 433         if (strcmp(op->name(), name) == 0) {
 434           info = &(funcs[i]);
 435           break;
 436         }
 437       }
 438 
 439       // check for platform dependent attach operation
 440       if (info == NULL) {
 441         info = AttachListener::pd_find_operation(op->name());
 442       }
 443 
 444       if (info != NULL) {
 445         // dispatch to the function that implements this operation
 446         res = (info->func)(op, &st);
 447       } else {
 448         st.print("Operation %s not recognized!", op->name());
 449         res = JNI_ERR;
 450       }
 451     }
 452 
 453     // operation complete - send result and output to client
 454     op->complete(res, &st);
 455   }
 456 }
 457 
 458 // Starts the Attach Listener thread
 459 void AttachListener::init() {
 460   EXCEPTION_MARK;
 461   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
 462   instanceKlassHandle klass (THREAD, k);
 463   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
 464 
 465   const char thread_name[] = "Attach Listener";
 466   Handle string = java_lang_String::create_from_str(thread_name, CHECK);
 467 
 468   // Initialize thread_oop to put it into the system threadGroup
 469   Handle thread_group (THREAD, Universe::system_thread_group());
 470   JavaValue result(T_VOID);
 471   JavaCalls::call_special(&result, thread_oop,
 472                        klass,
 473                        vmSymbols::object_initializer_name(),
 474                        vmSymbols::threadgroup_string_void_signature(),
 475                        thread_group,
 476                        string,
 477                        CHECK);
 478 
 479   KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
 480   JavaCalls::call_special(&result,
 481                         thread_group,
 482                         group,
 483                         vmSymbols::add_method_name(),
 484                         vmSymbols::thread_void_signature(),
 485                         thread_oop,             // ARG 1
 486                         CHECK);
 487 
 488   { MutexLocker mu(Threads_lock);
 489     JavaThread* listener_thread = new JavaThread(&attach_listener_thread_entry);
 490 
 491     // Check that thread and osthread were created
 492     if (listener_thread == NULL || listener_thread->osthread() == NULL) {
 493       vm_exit_during_initialization("java.lang.OutOfMemoryError",
 494                                     "unable to create new native thread");
 495     }
 496 
 497     java_lang_Thread::set_thread(thread_oop(), listener_thread);
 498     java_lang_Thread::set_daemon(thread_oop());
 499 
 500     listener_thread->set_threadObj(thread_oop());
 501     Threads::add(listener_thread);
 502     Thread::start(listener_thread);
 503   }
 504 }
 505 
 506 // Performs clean-up tasks on platforms where we can detect that the last
 507 // client has detached
 508 void AttachListener::detachall() {
 509   // call the platform dependent clean-up
 510   pd_detachall();
 511 }