1 /*
   2  * Copyright (c) 1997, 2019, 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_RUNTIME_OSTHREAD_HPP
  26 #define SHARE_RUNTIME_OSTHREAD_HPP
  27 
  28 #include "runtime/frame.hpp"
  29 #include "runtime/handles.hpp"
  30 #include "runtime/javaFrameAnchor.hpp"
  31 #include "runtime/objectMonitor.hpp"
  32 #include "utilities/macros.hpp"
  33 
  34 // The OSThread class holds OS-specific thread information.  It is equivalent
  35 // to the sys_thread_t structure of the classic JVM implementation.
  36 
  37 // The thread states represented by the ThreadState values are platform-specific
  38 // and are likely to be only approximate, because most OSes don't give you access
  39 // to precise thread state information.
  40 
  41 // Note: the ThreadState is legacy code and is not correctly implemented.
  42 // Uses of ThreadState need to be replaced by the state in the JavaThread.
  43 
  44 enum ThreadState {
  45   ALLOCATED,                    // Memory has been allocated but not initialized
  46   INITIALIZED,                  // The thread has been initialized but yet started
  47   RUNNABLE,                     // Has been started and is runnable, but not necessarily running
  48   MONITOR_WAIT,                 // Waiting on a contended monitor lock
  49   CONDVAR_WAIT,                 // Waiting on a condition variable
  50   OBJECT_WAIT,                  // Waiting on an Object.wait() call
  51   BREAKPOINTED,                 // Suspended at breakpoint
  52   SLEEPING,                     // Thread.sleep()
  53   ZOMBIE                        // All done, but not reclaimed yet
  54 };
  55 
  56 typedef int (*OSThreadStartFunc)(void*);
  57 
  58 class OSThread: public CHeapObj<mtThread> {
  59   friend class VMStructs;
  60   friend class JVMCIVMStructs;
  61  private:
  62   OSThreadStartFunc _start_proc;  // Thread start routine
  63   void* _start_parm;              // Thread start routine parameter
  64   volatile ThreadState _state;    // Thread state *hint*
  65   volatile jint _interrupted;     // Thread.isInterrupted state
  66 
  67   // Note:  _interrupted must be jint, so that Java intrinsics can access it.
  68   // The value stored there must be either 0 or 1.  It must be possible
  69   // for Java to emulate Thread.currentThread().isInterrupted() by performing
  70   // the double indirection Thread::current()->_osthread->_interrupted.
  71 
  72   // Methods
  73  public:
  74   void set_state(ThreadState state)                { _state = state; }
  75   ThreadState get_state()                          { return _state; }
  76 
  77   OSThread(OSThreadStartFunc start_proc, void* start_parm);
  78   ~OSThread();
  79 
  80   // Accessors
  81   OSThreadStartFunc start_proc() const              { return _start_proc; }
  82   void set_start_proc(OSThreadStartFunc start_proc) { _start_proc = start_proc; }
  83   void* start_parm() const                          { return _start_parm; }
  84   void set_start_parm(void* start_parm)             { _start_parm = start_parm; }
  85   // These are specialized on Windows.
  86 #ifndef _WINDOWS
  87   volatile bool interrupted() const                 { return _interrupted != 0; }
  88   void set_interrupted(bool z)                      { _interrupted = z ? 1 : 0; }
  89 #endif
  90   // Printing
  91   void print_on(outputStream* st) const;
  92   void print() const;
  93 
  94   // For java intrinsics:
  95   static ByteSize interrupted_offset()            { return byte_offset_of(OSThread, _interrupted); }
  96 
  97   // Platform dependent stuff
  98 #include OS_HEADER(osThread)
  99 
 100  public:
 101   static ByteSize thread_id_offset()              { return byte_offset_of(OSThread, _thread_id); }
 102   static size_t thread_id_size()                  { return sizeof(thread_id_t); }
 103 
 104   thread_id_t thread_id() const                   { return _thread_id; }
 105 
 106   void set_thread_id(thread_id_t id)              { _thread_id = id; }
 107 
 108  private:
 109   // _thread_id is kernel thread id (similar to LWP id on Solaris). Each
 110   // thread has a unique thread_id (BsdThreads or NPTL). It can be used
 111   // to access /proc.
 112   thread_id_t _thread_id;
 113 };
 114 
 115 
 116 // Utility class for use with condition variables:
 117 class OSThreadWaitState : public StackObj {
 118   OSThread*   _osthread;
 119   ThreadState _old_state;
 120  public:
 121   OSThreadWaitState(OSThread* osthread, bool is_object_wait) {
 122     _osthread  = osthread;
 123     _old_state = osthread->get_state();
 124     if (is_object_wait) {
 125       osthread->set_state(OBJECT_WAIT);
 126     } else {
 127       osthread->set_state(CONDVAR_WAIT);
 128     }
 129   }
 130   ~OSThreadWaitState() {
 131     _osthread->set_state(_old_state);
 132   }
 133 };
 134 
 135 
 136 // Utility class for use with contended monitors:
 137 class OSThreadContendState : public StackObj {
 138   OSThread*   _osthread;
 139   ThreadState _old_state;
 140  public:
 141   OSThreadContendState(OSThread* osthread) {
 142     _osthread  = osthread;
 143     _old_state = osthread->get_state();
 144     osthread->set_state(MONITOR_WAIT);
 145   }
 146   ~OSThreadContendState() {
 147     _osthread->set_state(_old_state);
 148   }
 149 };
 150 
 151 #endif // SHARE_RUNTIME_OSTHREAD_HPP