1 /*
   2  * Copyright (c) 2003, 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 #ifndef SHARE_VM_PRIMS_JVMTITHREADSTATE_HPP
  26 #define SHARE_VM_PRIMS_JVMTITHREADSTATE_HPP
  27 
  28 #include "jvmtifiles/jvmti.h"
  29 #include "memory/allocation.hpp"
  30 #include "memory/allocation.inline.hpp"
  31 #include "prims/jvmtiEventController.hpp"
  32 #include "runtime/thread.hpp"
  33 #include "utilities/growableArray.hpp"
  34 
  35 //
  36 // Forward Declarations
  37 //
  38 
  39 class JvmtiEnvBase;
  40 class JvmtiEnvThreadState;
  41 class JvmtiDynamicCodeEventCollector;
  42 
  43 enum JvmtiClassLoadKind {
  44   jvmti_class_load_kind_load = 100,
  45   jvmti_class_load_kind_retransform,
  46   jvmti_class_load_kind_redefine
  47 };
  48 
  49 ///////////////////////////////////////////////////////////////
  50 //
  51 // class JvmtiEnvThreadStateIterator
  52 //
  53 // The only safe means of iterating through the JvmtiEnvThreadStates
  54 // in a JvmtiThreadState.
  55 // Note that this iteratation includes invalid environments pending
  56 // deallocation -- in fact, some uses depend on this behavior.
  57 //
  58 class JvmtiEnvThreadStateIterator : public StackObj {
  59  private:
  60   JvmtiThreadState* state;
  61  public:
  62   JvmtiEnvThreadStateIterator(JvmtiThreadState* thread_state);
  63   ~JvmtiEnvThreadStateIterator();
  64   JvmtiEnvThreadState* first();
  65   JvmtiEnvThreadState* next(JvmtiEnvThreadState* ets);
  66 };
  67 
  68 
  69 ///////////////////////////////////////////////////////////////
  70 //
  71 // class JvmtiThreadState
  72 //
  73 // The Jvmti state for each thread (across all JvmtiEnv):
  74 // 1. Local table of enabled events.
  75 class JvmtiThreadState : public CHeapObj<mtInternal> {
  76  private:
  77   friend class JvmtiEnv;
  78   JavaThread        *_thread;
  79   bool              _hide_single_stepping;
  80   bool              _pending_step_for_popframe;
  81   bool              _pending_step_for_earlyret;
  82   int               _hide_level;
  83 
  84  public:
  85   enum ExceptionState {
  86     ES_CLEARED,
  87     ES_DETECTED,
  88     ES_CAUGHT
  89   };
  90 
  91  private:
  92   ExceptionState _exception_state;
  93 
  94   // Used to send class being redefined/retransformed and kind of transform
  95   // info to the class file load hook event handler.
  96   Klass*                _class_being_redefined;
  97   JvmtiClassLoadKind    _class_load_kind;
  98 
  99   // This is only valid when is_interp_only_mode() returns true
 100   int               _cur_stack_depth;
 101 
 102   JvmtiThreadEventEnable _thread_event_enable;
 103 
 104   // for support of JvmtiEnvThreadState
 105   JvmtiEnvThreadState*   _head_env_thread_state;
 106 
 107   // doubly-linked linear list of active thread state
 108   // needed in order to iterate the list without holding Threads_lock
 109   static JvmtiThreadState *_head;
 110   JvmtiThreadState *_next;
 111   JvmtiThreadState *_prev;
 112 
 113   // holds the current dynamic code event collector, NULL if no event collector in use
 114   JvmtiDynamicCodeEventCollector* _dynamic_code_event_collector;
 115   // holds the current vm object alloc event collector, NULL if no event collector in use
 116   JvmtiVMObjectAllocEventCollector* _vm_object_alloc_event_collector;
 117 
 118   // Should only be created by factory methods
 119   JvmtiThreadState(JavaThread *thread);
 120 
 121   friend class JvmtiEnvThreadStateIterator;
 122   inline JvmtiEnvThreadState* head_env_thread_state();
 123   inline void set_head_env_thread_state(JvmtiEnvThreadState* ets);
 124 
 125  public:
 126   ~JvmtiThreadState();
 127 
 128   // is event_type enabled and usable for this thread in any enviroments?
 129   bool is_enabled(jvmtiEvent event_type) {
 130     return _thread_event_enable.is_enabled(event_type);
 131   }
 132 
 133   JvmtiThreadEventEnable *thread_event_enable() {
 134     return &_thread_event_enable;
 135   }
 136 
 137   // Must only be called in situations where the state is for the current thread and
 138   // the environment can not go away.  To be safe, the returned JvmtiEnvThreadState
 139   // must be used in such a way as there can be no intervening safepoints.
 140   inline JvmtiEnvThreadState* env_thread_state(JvmtiEnvBase *env);
 141 
 142   static void periodic_clean_up();
 143 
 144   void add_env(JvmtiEnvBase *env);
 145 
 146   // Used by the interpreter for fullspeed debugging support
 147   bool is_interp_only_mode()                { return _thread->is_interp_only_mode(); }
 148   void enter_interp_only_mode();
 149   void leave_interp_only_mode();
 150 
 151   // access to the linked list of all JVMTI thread states
 152   static JvmtiThreadState *first() {
 153     assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
 154     return _head;
 155   }
 156 
 157   JvmtiThreadState *next()                  {
 158     return _next;
 159   }
 160 
 161   // Current stack depth is only valid when is_interp_only_mode() returns true.
 162   // These functions should only be called at a safepoint - usually called from same thread.
 163   // Returns the number of Java activations on the stack.
 164   int cur_stack_depth();
 165   void invalidate_cur_stack_depth();
 166   void incr_cur_stack_depth();
 167   void decr_cur_stack_depth();
 168 
 169   int count_frames();
 170 
 171   inline JavaThread *get_thread()      { return _thread;              }
 172 
 173   inline bool is_exception_detected()  { return _exception_state == ES_DETECTED;  }
 174   inline bool is_exception_caught()    { return _exception_state == ES_CAUGHT;  }
 175 
 176   inline void set_exception_detected() { _exception_state = ES_DETECTED; }
 177   inline void set_exception_caught()   { _exception_state = ES_CAUGHT; }
 178 
 179   inline void clear_exception_state() { _exception_state = ES_CLEARED; }
 180 
 181   // We need to save and restore exception state inside JvmtiEventMark
 182   inline ExceptionState get_exception_state() { return _exception_state; }
 183   inline void restore_exception_state(ExceptionState state) { _exception_state = state; }
 184 
 185   inline void clear_hide_single_stepping() {
 186     if (_hide_level > 0) {
 187       _hide_level--;
 188     } else {
 189       assert(_hide_single_stepping, "hide_single_stepping is out of phase");
 190       _hide_single_stepping = false;
 191     }
 192   }
 193   inline bool hide_single_stepping() { return _hide_single_stepping; }
 194   inline void set_hide_single_stepping() {
 195     if (_hide_single_stepping) {
 196       _hide_level++;
 197     } else {
 198       assert(_hide_level == 0, "hide_level is out of phase");
 199       _hide_single_stepping = true;
 200     }
 201   }
 202 
 203   // Step pending flag is set when PopFrame is called and it is cleared
 204   // when step for the Pop Frame is completed.
 205   // This logic is used to distinguish b/w step for pop frame and repeat step.
 206   void set_pending_step_for_popframe() { _pending_step_for_popframe = true;  }
 207   void clr_pending_step_for_popframe() { _pending_step_for_popframe = false; }
 208   bool is_pending_step_for_popframe()  { return _pending_step_for_popframe;  }
 209   void process_pending_step_for_popframe();
 210 
 211   // Step pending flag is set when ForceEarlyReturn is called and it is cleared
 212   // when step for the ForceEarlyReturn is completed.
 213   // This logic is used to distinguish b/w step for early return and repeat step.
 214   void set_pending_step_for_earlyret() { _pending_step_for_earlyret = true;  }
 215   void clr_pending_step_for_earlyret() { _pending_step_for_earlyret = false; }
 216   bool is_pending_step_for_earlyret()  { return _pending_step_for_earlyret;  }
 217   void process_pending_step_for_earlyret();
 218 
 219   // Setter and getter method is used to send redefined class info
 220   // when class file load hook event is posted.
 221   // It is set while loading redefined class and cleared before the
 222   // class file load hook event is posted.
 223   inline void set_class_being_redefined(Klass* k, JvmtiClassLoadKind kind) {
 224     _class_being_redefined = k;
 225     _class_load_kind = kind;
 226   }
 227 
 228   inline void clear_class_being_redefined() {
 229     _class_being_redefined = NULL;
 230     _class_load_kind = jvmti_class_load_kind_load;
 231   }
 232 
 233   inline Klass* get_class_being_redefined() {
 234     return _class_being_redefined;
 235   }
 236 
 237   inline JvmtiClassLoadKind get_class_load_kind() {
 238     return _class_load_kind;
 239   }
 240 
 241   // RedefineClasses support
 242   // The bug 6214132 caused the verification to fail.
 243   //
 244   // Below is the detailed description of the fix approach taken:
 245   // 1. What's done in RedefineClasses() before verification:
 246   //  a) A reference to the class being redefined (_the_class) and a
 247   //     reference to new version of the class (_scratch_class) are
 248   //     saved here for use during the bytecode verification phase of
 249   //     RedefineClasses. See RedefineVerifyMark for how these fields
 250   //     are managed.
 251   //   b) The _java_mirror field from _the_class is copied to the
 252   //     _java_mirror field in _scratch_class. This means that a jclass
 253   //     returned for _the_class or _scratch_class will refer to the
 254   //     same Java mirror. The verifier will see the "one true mirror"
 255   //     for the class being verified.
 256   // 2. What is done at verification:
 257   //   When the verifier makes calls into the VM to ask questions about
 258   //   the class being verified, it will pass the jclass to JVM_* functions.
 259   //   The jclass is always pointing to the mirror of _the_class.
 260   //   ~28 JVM_* functions called by the verifier for the information
 261   //   about CP entries and klass structure should check the jvmtiThreadState
 262   //   info about equivalent klass versions and use it to replace a Klass*
 263   //   of _the_class with a Klass* of _scratch_class. The function
 264   //   class_to_verify_considering_redefinition() must be called for it.
 265   //
 266   //   Note again, that this redirection happens only for the verifier thread.
 267   //   Other threads have very small overhead by checking the existence
 268   //   of the jvmtiThreadSate and the information about klasses equivalence.
 269   //   No JNI functions need to be changed, they don't reference the klass guts.
 270   //   The JavaThread pointer is already available in all JVM_* functions
 271   //   used by the verifier, so there is no extra performance issue with it.
 272 
 273  private:
 274   Klass* _the_class_for_redefinition_verification;
 275   Klass* _scratch_class_for_redefinition_verification;
 276 
 277  public:
 278   inline void set_class_versions_map(Klass* the_class,
 279                                      Klass* scratch_class) {
 280     _the_class_for_redefinition_verification = the_class;
 281     _scratch_class_for_redefinition_verification = scratch_class;
 282   }
 283 
 284   inline void clear_class_versions_map() { set_class_versions_map(NULL, NULL); }
 285 
 286   static inline
 287   Klass* class_to_verify_considering_redefinition(Klass* klass,
 288                                                     JavaThread *thread) {
 289     JvmtiThreadState *state = thread->jvmti_thread_state();
 290     if (state != NULL && state->_the_class_for_redefinition_verification != NULL) {
 291       if (state->_the_class_for_redefinition_verification == klass) {
 292         klass = state->_scratch_class_for_redefinition_verification;
 293       }
 294     }
 295     return klass;
 296   }
 297 
 298   // Todo: get rid of this!
 299  private:
 300   bool _debuggable;
 301  public:
 302   // Should the thread be enumerated by jvmtiInternal::GetAllThreads?
 303   bool is_debuggable()                 { return _debuggable; }
 304   // If a thread cannot be suspended (has no valid last_java_frame) then it gets marked !debuggable
 305   void set_debuggable(bool debuggable) { _debuggable = debuggable; }
 306 
 307  public:
 308 
 309   bool may_be_walked();
 310 
 311   // Thread local event collector setter and getter methods.
 312   JvmtiDynamicCodeEventCollector* get_dynamic_code_event_collector() {
 313     return _dynamic_code_event_collector;
 314   }
 315   JvmtiVMObjectAllocEventCollector* get_vm_object_alloc_event_collector() {
 316     return _vm_object_alloc_event_collector;
 317   }
 318   void set_dynamic_code_event_collector(JvmtiDynamicCodeEventCollector* collector) {
 319     _dynamic_code_event_collector = collector;
 320   }
 321   void set_vm_object_alloc_event_collector(JvmtiVMObjectAllocEventCollector* collector) {
 322     _vm_object_alloc_event_collector = collector;
 323   }
 324 
 325 
 326   //
 327   // Frame routines
 328   //
 329 
 330  public:
 331 
 332   //  true when the thread was suspended with a pointer to the last Java frame.
 333   bool has_last_frame()                     { return _thread->has_last_Java_frame(); }
 334 
 335   void update_for_pop_top_frame();
 336 
 337   // already holding JvmtiThreadState_lock - retrieve or create JvmtiThreadState
 338   // Can return NULL if JavaThread is exiting.
 339   inline static JvmtiThreadState *state_for_while_locked(JavaThread *thread) {
 340     assert(JvmtiThreadState_lock->is_locked(), "sanity check");
 341 
 342     JvmtiThreadState *state = thread->jvmti_thread_state();
 343     if (state == NULL) {
 344       if (thread->is_exiting()) {
 345         // don't add a JvmtiThreadState to a thread that is exiting
 346         return NULL;
 347       }
 348 
 349       state = new JvmtiThreadState(thread);
 350     }
 351     return state;
 352   }
 353 
 354   // retrieve or create JvmtiThreadState
 355   // Can return NULL if JavaThread is exiting.
 356   inline static JvmtiThreadState *state_for(JavaThread *thread) {
 357     JvmtiThreadState *state = thread->jvmti_thread_state();
 358     if (state == NULL) {
 359       MutexLocker mu(JvmtiThreadState_lock);
 360       // check again with the lock held
 361       state = state_for_while_locked(thread);
 362     } else {
 363       CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
 364     }
 365     return state;
 366   }
 367 
 368   // JVMTI ForceEarlyReturn support
 369 
 370   // This is set to earlyret_pending to signal that top Java frame
 371   // should be returned immediately
 372  public:
 373   int           _earlyret_state;
 374   TosState      _earlyret_tos;
 375   jvalue        _earlyret_value;
 376   oop           _earlyret_oop;         // Used to return an oop result into Java code from
 377                                        // ForceEarlyReturnObject, GC-preserved
 378 
 379   // Setting and clearing earlyret_state
 380   // earlyret_pending indicates that a ForceEarlyReturn() has been
 381   // requested and not yet been completed.
 382  public:
 383   enum EarlyretState {
 384     earlyret_inactive = 0,
 385     earlyret_pending  = 1
 386   };
 387 
 388   void set_earlyret_pending(void) { _earlyret_state = earlyret_pending;  }
 389   void clr_earlyret_pending(void) { _earlyret_state = earlyret_inactive; }
 390   bool is_earlyret_pending(void)  { return (_earlyret_state == earlyret_pending);  }
 391 
 392   TosState earlyret_tos()                            { return _earlyret_tos; }
 393   oop  earlyret_oop() const                          { return _earlyret_oop; }
 394   void set_earlyret_oop (oop x)                      { _earlyret_oop = x;    }
 395   jvalue earlyret_value()                            { return _earlyret_value; }
 396   void set_earlyret_value(jvalue val, TosState tos)  { _earlyret_tos = tos;  _earlyret_value = val;  }
 397   void clr_earlyret_value()                          { _earlyret_tos = ilgl; _earlyret_value.j = 0L; }
 398 
 399   static ByteSize earlyret_state_offset() { return byte_offset_of(JvmtiThreadState, _earlyret_state); }
 400   static ByteSize earlyret_tos_offset()   { return byte_offset_of(JvmtiThreadState, _earlyret_tos); }
 401   static ByteSize earlyret_oop_offset()   { return byte_offset_of(JvmtiThreadState, _earlyret_oop); }
 402   static ByteSize earlyret_value_offset() { return byte_offset_of(JvmtiThreadState, _earlyret_value); }
 403 
 404   void oops_do(OopClosure* f) NOT_JVMTI_RETURN; // GC support
 405 
 406 public:
 407   void set_should_post_on_exceptions(bool val) { _thread->set_should_post_on_exceptions_flag(val ? JNI_TRUE : JNI_FALSE); }
 408 };
 409 
 410 class RedefineVerifyMark : public StackObj {
 411  private:
 412   JvmtiThreadState* _state;
 413   Klass*            _scratch_class;
 414   Handle            _scratch_mirror;
 415 
 416  public:
 417   RedefineVerifyMark(Klass* the_class, Klass* scratch_class,
 418                      JvmtiThreadState *state) : _state(state), _scratch_class(scratch_class)
 419   {
 420     _state->set_class_versions_map(the_class, scratch_class);
 421     Thread* thread = Thread::current();
 422     _scratch_mirror = Handle(thread, _scratch_class->java_mirror());
 423     Handle the_mirror(thread, the_class->java_mirror());
 424     _scratch_class->set_java_mirror(the_mirror);
 425   }
 426 
 427   ~RedefineVerifyMark() {
 428     // Restore the scratch class's mirror, so when scratch_class is removed
 429     // the correct mirror pointing to it can be cleared.
 430     _scratch_class->set_java_mirror(_scratch_mirror);
 431     _state->clear_class_versions_map();
 432   }
 433 };
 434 
 435 #endif // SHARE_VM_PRIMS_JVMTITHREADSTATE_HPP