1 /*
   2  * Copyright (c) 2005, 2018, 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 "oops/typeArrayOop.inline.hpp"
  32 #include "prims/jvmtiExport.hpp"
  33 #include "runtime/arguments.hpp"
  34 #include "runtime/globals.hpp"
  35 #include "runtime/handles.inline.hpp"
  36 #include "runtime/java.hpp"
  37 #include "runtime/javaCalls.hpp"
  38 #include "runtime/os.hpp"
  39 #include "services/attachListener.hpp"
  40 #include "services/diagnosticCommand.hpp"
  41 #include "services/heapDumper.hpp"
  42 #include "services/writeableFlags.hpp"
  43 #include "utilities/debug.hpp"
  44 #include "utilities/formatBuffer.hpp"
  45 
  46 volatile bool AttachListener::_initialized;
  47 
  48 // Implementation of "properties" command.
  49 //
  50 // Invokes VMSupport.serializePropertiesToByteArray to serialize
  51 // the system properties into a byte array.
  52 
  53 static InstanceKlass* load_and_initialize_klass(Symbol* sh, TRAPS) {
  54   Klass* k = SystemDictionary::resolve_or_fail(sh, true, CHECK_NULL);
  55   InstanceKlass* ik = InstanceKlass::cast(k);
  56   if (ik->should_be_initialized()) {
  57     ik->initialize(CHECK_NULL);
  58   }
  59   return ik;
  60 }
  61 
  62 static jint get_properties(AttachOperation* op, outputStream* out, Symbol* serializePropertiesMethod) {
  63   Thread* THREAD = Thread::current();
  64   HandleMark hm;
  65 
  66   // load VMSupport
  67   Symbol* klass = vmSymbols::jdk_internal_vm_VMSupport();
  68   InstanceKlass* k = load_and_initialize_klass(klass, THREAD);
  69   if (HAS_PENDING_EXCEPTION) {
  70     java_lang_Throwable::print(PENDING_EXCEPTION, out);
  71     CLEAR_PENDING_EXCEPTION;
  72     return JNI_ERR;
  73   }
  74 
  75   // invoke the serializePropertiesToByteArray method
  76   JavaValue result(T_OBJECT);
  77   JavaCallArguments args;
  78 
  79 
  80   Symbol* signature = vmSymbols::serializePropertiesToByteArray_signature();
  81   JavaCalls::call_static(&result,
  82                          k,
  83                          serializePropertiesMethod,
  84                          signature,
  85                          &args,
  86                          THREAD);
  87   if (HAS_PENDING_EXCEPTION) {
  88     java_lang_Throwable::print(PENDING_EXCEPTION, out);
  89     CLEAR_PENDING_EXCEPTION;
  90     return JNI_ERR;
  91   }
  92 
  93   // The result should be a [B
  94   oop res = (oop)result.get_jobject();
  95   assert(res->is_typeArray(), "just checking");
  96   assert(TypeArrayKlass::cast(res->klass())->element_type() == T_BYTE, "just checking");
  97 
  98   // copy the bytes to the output stream
  99   typeArrayOop ba = typeArrayOop(res);
 100   jbyte* addr = typeArrayOop(res)->byte_at_addr(0);
 101   out->print_raw((const char*)addr, ba->length());
 102 
 103   return JNI_OK;
 104 }
 105 
 106 // Implementation of "load" command.
 107 static jint load_agent(AttachOperation* op, outputStream* out) {
 108   // get agent name and options
 109   const char* agent = op->arg(0);
 110   const char* absParam = op->arg(1);
 111   const char* options = op->arg(2);
 112 
 113   // If loading a java agent then need to ensure that the java.instrument module is loaded
 114   if (strcmp(agent, "instrument") == 0) {
 115     Thread* THREAD = Thread::current();
 116     ResourceMark rm(THREAD);
 117     HandleMark hm(THREAD);
 118     JavaValue result(T_OBJECT);
 119     Handle h_module_name = java_lang_String::create_from_str("java.instrument", THREAD);
 120     JavaCalls::call_static(&result,
 121                            SystemDictionary::module_Modules_klass(),
 122                            vmSymbols::loadModule_name(),
 123                            vmSymbols::loadModule_signature(),
 124                            h_module_name,
 125                            THREAD);
 126     if (HAS_PENDING_EXCEPTION) {
 127       java_lang_Throwable::print(PENDING_EXCEPTION, out);
 128       CLEAR_PENDING_EXCEPTION;
 129       return JNI_ERR;
 130     }
 131   }
 132 
 133   return JvmtiExport::load_agent_library(agent, absParam, options, out);
 134 }
 135 
 136 // Implementation of "properties" command.
 137 // See also: PrintSystemPropertiesDCmd class
 138 static jint get_system_properties(AttachOperation* op, outputStream* out) {
 139   return get_properties(op, out, vmSymbols::serializePropertiesToByteArray_name());
 140 }
 141 
 142 // Implementation of "agent_properties" command.
 143 static jint get_agent_properties(AttachOperation* op, outputStream* out) {
 144   return get_properties(op, out, vmSymbols::serializeAgentPropertiesToByteArray_name());
 145 }
 146 
 147 // Implementation of "datadump" command.
 148 //
 149 // Raises a SIGBREAK signal so that VM dump threads, does deadlock detection,
 150 // etc. In theory this command should only post a DataDumpRequest to any
 151 // JVMTI environment that has enabled this event. However it's useful to
 152 // trigger the SIGBREAK handler.
 153 
 154 static jint data_dump(AttachOperation* op, outputStream* out) {
 155   if (!ReduceSignalUsage) {
 156     AttachListener::pd_data_dump();
 157   } else {
 158     if (JvmtiExport::should_post_data_dump()) {
 159       JvmtiExport::post_data_dump();
 160     }
 161   }
 162   return JNI_OK;
 163 }
 164 
 165 // Implementation of "threaddump" command - essentially a remote ctrl-break
 166 // See also: ThreadDumpDCmd class
 167 //
 168 static jint thread_dump(AttachOperation* op, outputStream* out) {
 169   bool print_concurrent_locks = false;
 170   if (op->arg(0) != NULL && strcmp(op->arg(0), "-l") == 0) {
 171     print_concurrent_locks = true;
 172   }
 173 
 174   // thread stacks
 175   VM_PrintThreads op1(out, print_concurrent_locks);
 176   VMThread::execute(&op1);
 177 
 178   // JNI global handles
 179   VM_PrintJNI op2(out);
 180   VMThread::execute(&op2);
 181 
 182   // Deadlock detection
 183   VM_FindDeadlocks op3(out);
 184   VMThread::execute(&op3);
 185 
 186   return JNI_OK;
 187 }
 188 
 189 // A jcmd attach operation request was received, which will now
 190 // dispatch to the diagnostic commands used for serviceability functions.
 191 static jint jcmd(AttachOperation* op, outputStream* out) {
 192   Thread* THREAD = Thread::current();
 193   // All the supplied jcmd arguments are stored as a single
 194   // string (op->arg(0)). This is parsed by the Dcmd framework.
 195   DCmd::parse_and_execute(DCmd_Source_AttachAPI, out, op->arg(0), ' ', THREAD);
 196   if (HAS_PENDING_EXCEPTION) {
 197     java_lang_Throwable::print(PENDING_EXCEPTION, out);
 198     out->cr();
 199     CLEAR_PENDING_EXCEPTION;
 200     return JNI_ERR;
 201   }
 202   return JNI_OK;
 203 }
 204 
 205 // Implementation of "dumpheap" command.
 206 // See also: HeapDumpDCmd class
 207 //
 208 // Input arguments :-
 209 //   arg0: Name of the dump file
 210 //   arg1: "-live" or "-all"
 211 jint dump_heap(AttachOperation* op, outputStream* out) {
 212   const char* path = op->arg(0);
 213   if (path == NULL || path[0] == '\0') {
 214     out->print_cr("No dump file specified");
 215   } else {
 216     bool live_objects_only = true;   // default is true to retain the behavior before this change is made
 217     const char* arg1 = op->arg(1);
 218     if (arg1 != NULL && (strlen(arg1) > 0)) {
 219       if (strcmp(arg1, "-all") != 0 && strcmp(arg1, "-live") != 0) {
 220         out->print_cr("Invalid argument to dumpheap operation: %s", arg1);
 221         return JNI_ERR;
 222       }
 223       live_objects_only = strcmp(arg1, "-live") == 0;
 224     }
 225 
 226     // Request a full GC before heap dump if live_objects_only = true
 227     // This helps reduces the amount of unreachable objects in the dump
 228     // and makes it easier to browse.
 229     HeapDumper dumper(live_objects_only /* request GC */);
 230     int res = dumper.dump(op->arg(0));
 231     if (res == 0) {
 232       out->print_cr("Heap dump file created");
 233     } else {
 234       // heap dump failed
 235       ResourceMark rm;
 236       char* error = dumper.error_as_C_string();
 237       if (error == NULL) {
 238         out->print_cr("Dump failed - reason unknown");
 239       } else {
 240         out->print_cr("%s", error);
 241       }
 242     }
 243   }
 244   return JNI_OK;
 245 }
 246 
 247 // Implementation of "inspectheap" command
 248 // See also: ClassHistogramDCmd class
 249 //
 250 // Input arguments :-
 251 //   arg0: "-live" or "-all"
 252 static jint heap_inspection(AttachOperation* op, outputStream* out) {
 253   bool live_objects_only = true;   // default is true to retain the behavior before this change is made
 254   const char* arg0 = op->arg(0);
 255   if (arg0 != NULL && (strlen(arg0) > 0)) {
 256     if (strcmp(arg0, "-all") != 0 && strcmp(arg0, "-live") != 0) {
 257       out->print_cr("Invalid argument to inspectheap operation: %s", arg0);
 258       return JNI_ERR;
 259     }
 260     live_objects_only = strcmp(arg0, "-live") == 0;
 261   }
 262   VM_GC_HeapInspection heapop(out, live_objects_only /* request full gc */);
 263   VMThread::execute(&heapop);
 264   return JNI_OK;
 265 }
 266 
 267 // Implementation of "setflag" command
 268 static jint set_flag(AttachOperation* op, outputStream* out) {
 269 
 270   const char* name = NULL;
 271   if ((name = op->arg(0)) == NULL) {
 272     out->print_cr("flag name is missing");
 273     return JNI_ERR;
 274   }
 275 
 276   FormatBuffer<80> err_msg("%s", "");
 277 
 278   int ret = WriteableFlags::set_flag(op->arg(0), op->arg(1), Flag::ATTACH_ON_DEMAND, err_msg);
 279   if (ret != Flag::SUCCESS) {
 280     if (ret == Flag::NON_WRITABLE) {
 281       // if the flag is not manageable try to change it through
 282       // the platform dependent implementation
 283       return AttachListener::pd_set_flag(op, out);
 284     } else {
 285       out->print_cr("%s", err_msg.buffer());
 286     }
 287 
 288     return JNI_ERR;
 289   }
 290   return JNI_OK;
 291 }
 292 
 293 // Implementation of "printflag" command
 294 // See also: PrintVMFlagsDCmd class
 295 static jint print_flag(AttachOperation* op, outputStream* out) {
 296   const char* name = NULL;
 297   if ((name = op->arg(0)) == NULL) {
 298     out->print_cr("flag name is missing");
 299     return JNI_ERR;
 300   }
 301   Flag* f = Flag::find_flag((char*)name, strlen(name));
 302   if (f) {
 303     f->print_as_flag(out);
 304     out->cr();
 305   } else {
 306     out->print_cr("no such flag '%s'", name);
 307   }
 308   return JNI_OK;
 309 }
 310 
 311 // Table to map operation names to functions.
 312 
 313 // names must be of length <= AttachOperation::name_length_max
 314 static AttachOperationFunctionInfo funcs[] = {
 315   { "agentProperties",  get_agent_properties },
 316   { "datadump",         data_dump },
 317   { "dumpheap",         dump_heap },
 318   { "load",             load_agent },
 319   { "properties",       get_system_properties },
 320   { "threaddump",       thread_dump },
 321   { "inspectheap",      heap_inspection },
 322   { "setflag",          set_flag },
 323   { "printflag",        print_flag },
 324   { "jcmd",             jcmd },
 325   { NULL,               NULL }
 326 };
 327 
 328 
 329 
 330 // The Attach Listener threads services a queue. It dequeues an operation
 331 // from the queue, examines the operation name (command), and dispatches
 332 // to the corresponding function to perform the operation.
 333 
 334 static void attach_listener_thread_entry(JavaThread* thread, TRAPS) {
 335   os::set_priority(thread, NearMaxPriority);
 336 
 337   assert(thread == Thread::current(), "Must be");
 338   assert(thread->stack_base() != NULL && thread->stack_size() > 0,
 339          "Should already setup");
 340 
 341   if (AttachListener::pd_init() != 0) {
 342     return;
 343   }
 344   AttachListener::set_initialized();
 345 
 346   for (;;) {
 347     AttachOperation* op = AttachListener::dequeue();
 348     if (op == NULL) {
 349       return;   // dequeue failed or shutdown
 350     }
 351 
 352     ResourceMark rm;
 353     bufferedStream st;
 354     jint res = JNI_OK;
 355 
 356     // handle special detachall operation
 357     if (strcmp(op->name(), AttachOperation::detachall_operation_name()) == 0) {
 358       AttachListener::detachall();
 359     } else if (!EnableDynamicAgentLoading && strcmp(op->name(), "load") == 0) {
 360       st.print("Dynamic agent loading is not enabled. "
 361                "Use -XX:+EnableDynamicAgentLoading to launch target VM.");
 362       res = JNI_ERR;
 363     } else {
 364       // find the function to dispatch too
 365       AttachOperationFunctionInfo* info = NULL;
 366       for (int i=0; funcs[i].name != NULL; i++) {
 367         const char* name = funcs[i].name;
 368         assert(strlen(name) <= AttachOperation::name_length_max, "operation <= name_length_max");
 369         if (strcmp(op->name(), name) == 0) {
 370           info = &(funcs[i]);
 371           break;
 372         }
 373       }
 374 
 375       // check for platform dependent attach operation
 376       if (info == NULL) {
 377         info = AttachListener::pd_find_operation(op->name());
 378       }
 379 
 380       if (info != NULL) {
 381         // dispatch to the function that implements this operation
 382         res = (info->func)(op, &st);
 383       } else {
 384         st.print("Operation %s not recognized!", op->name());
 385         res = JNI_ERR;
 386       }
 387     }
 388 
 389     // operation complete - send result and output to client
 390     op->complete(res, &st);
 391   }
 392 }
 393 
 394 bool AttachListener::has_init_error(TRAPS) {
 395   if (HAS_PENDING_EXCEPTION) {
 396     tty->print_cr("Exception in VM (AttachListener::init) : ");
 397     java_lang_Throwable::print(PENDING_EXCEPTION, tty);
 398     tty->cr();
 399 
 400     CLEAR_PENDING_EXCEPTION;
 401 
 402     return true;
 403   } else {
 404     return false;
 405   }
 406 }
 407 
 408 // Starts the Attach Listener thread
 409 void AttachListener::init() {
 410   EXCEPTION_MARK;
 411   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, THREAD);
 412   if (has_init_error(THREAD)) {
 413     return;
 414   }
 415 
 416   InstanceKlass* klass = InstanceKlass::cast(k);
 417   instanceHandle thread_oop = klass->allocate_instance_handle(THREAD);
 418   if (has_init_error(THREAD)) {
 419     return;
 420   }
 421 
 422   const char thread_name[] = "Attach Listener";
 423   Handle string = java_lang_String::create_from_str(thread_name, THREAD);
 424   if (has_init_error(THREAD)) {
 425     return;
 426   }
 427 
 428   // Initialize thread_oop to put it into the system threadGroup
 429   Handle thread_group (THREAD, Universe::system_thread_group());
 430   JavaValue result(T_VOID);
 431   JavaCalls::call_special(&result, thread_oop,
 432                        klass,
 433                        vmSymbols::object_initializer_name(),
 434                        vmSymbols::threadgroup_string_void_signature(),
 435                        thread_group,
 436                        string,
 437                        THREAD);
 438 
 439   if (has_init_error(THREAD)) {
 440     return;
 441   }
 442 
 443   Klass* group = SystemDictionary::ThreadGroup_klass();
 444   JavaCalls::call_special(&result,
 445                         thread_group,
 446                         group,
 447                         vmSymbols::add_method_name(),
 448                         vmSymbols::thread_void_signature(),
 449                         thread_oop,             // ARG 1
 450                         THREAD);
 451   if (has_init_error(THREAD)) {
 452     return;
 453   }
 454 
 455   { MutexLocker mu(Threads_lock);
 456     JavaThread* listener_thread = new JavaThread(&attach_listener_thread_entry);
 457 
 458     // Check that thread and osthread were created
 459     if (listener_thread == NULL || listener_thread->osthread() == NULL) {
 460       vm_exit_during_initialization("java.lang.OutOfMemoryError",
 461                                     os::native_thread_creation_failed_msg());
 462     }
 463 
 464     java_lang_Thread::set_thread(thread_oop(), listener_thread);
 465     java_lang_Thread::set_daemon(thread_oop());
 466 
 467     listener_thread->set_threadObj(thread_oop());
 468     Threads::add(listener_thread);
 469     Thread::start(listener_thread);
 470   }
 471 }
 472 
 473 // Performs clean-up tasks on platforms where we can detect that the last
 474 // client has detached
 475 void AttachListener::detachall() {
 476   // call the platform dependent clean-up
 477   pd_detachall();
 478 }