libjava/include/posix-threads.h

   1 // -*- c++ -*-
   2 // posix-threads.h - Defines for using POSIX threads.
   3
   4 /* Copyright (C) 1998, 1999  Cygnus Solutions
   5
   6    This file is part of libgcj.
   7
   8 This software is copyrighted work licensed under the terms of the
   9 Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
  10 details.  */
  11
  12 #ifndef __JV_POSIX_THREADS__
  13 #define __JV_POSIX_THREADS__
  14
  15 // NOTE: This file may only reference those pthread functions which
  16 // are known not to be overridden by the Boehm GC.  If in doubt, scan
  17 // boehm-gc/gc.h.  This is yucky but lets us avoid including gc.h
  18 // everywhere (which would be truly yucky).
  19
  20 #include <pthread.h>
  21 #include <sched.h>
  22
  23 #if defined (HAVE_PTHREAD_MUTEXATTR_SETTYPE) || defined (HAVE_PTHREAD_MUTEXATTR_SETKIND_NP)
  24 #  define HAVE_RECURSIVE_MUTEX 1
  25 #endif
  26
  27
  28 //
  29 // Typedefs.
  30 //
  31
  32 typedef pthread_cond_t _Jv_ConditionVariable_t;
  33
  34 #if defined (PTHREAD_MUTEX_HAVE_M_COUNT) || defined (PTHREAD_MUTEX_HAVE___M_COUNT)
  35
  36 // On Linux we use implementation details of mutexes in order to get
  37 // faster results.
  38 typedef pthread_mutex_t _Jv_Mutex_t;
  39
  40 #else /* LINUX_THREADS */
  41
  42 #define PTHREAD_MUTEX_IS_STRUCT
  43
  44 typedef struct
  45 {
  46   // Mutex used when locking this structure transiently.
  47   pthread_mutex_t mutex;
  48 #ifndef HAVE_RECURSIVE_MUTEX
  49   // Some systems do not have recursive mutexes, so we must simulate
  50   // them.  Solaris is one such system.
  51
  52   // Mutex the thread holds the entire time this mutex is held.  This
  53   // is used to make condition variables work properly.
  54   pthread_mutex_t mutex2;
  55   // Condition variable used when waiting for this lock.
  56   pthread_cond_t cond;
  57   // Thread holding this mutex.  If COUNT is 0, no thread is holding.
  58   pthread_t thread;
  59 #endif /* HAVE_RECURSIVE_MUTEX */
  60
  61   // Number of times mutex is held.  If 0, the lock is not held.  We
  62   // do this even if we have a native recursive mutex so that we can
  63   // keep track of whether the lock is held; this lets us do error
  64   // checking.  FIXME it would be nice to optimize this; on some
  65   // systems we could do so by relying on implementation details of
  66   // recursive mutexes.
  67   int count;
  68 } _Jv_Mutex_t;
  69
  70 #endif
  71
  72 typedef struct
  73 {
  74   // Flag values are defined in implementation.
  75   int flags;
  76
  77   // Actual thread id.
  78   pthread_t thread;
  79 } _Jv_Thread_t;
  80 typedef void _Jv_ThreadStartFunc (java::lang::Thread *);
  81
  82
  83 // This convenience function is used to return the POSIX mutex
  84 // corresponding to our mutex.
  85 inline pthread_mutex_t *
  86 _Jv_PthreadGetMutex (_Jv_Mutex_t *mu)
  87 {
  88 #if ! defined (PTHREAD_MUTEX_IS_STRUCT)
  89   return mu;
  90 #elif defined (HAVE_RECURSIVE_MUTEX)
  91   return &mu->mutex;
  92 #else
  93   return &mu->mutex2;
  94 #endif
  95 }
  96
  97 #include <stdio.h>
  98
  99 // This is a convenience function used only by the pthreads thread
 100 // implementation.  This is slow, but that's too bad -- we need to do
 101 // the checks for correctness.  It might be nice to be able to compile
 102 // this out.
 103 inline int
 104 _Jv_PthreadCheckMonitor (_Jv_Mutex_t *mu)
 105 {
 106   pthread_mutex_t *pmu = _Jv_PthreadGetMutex (mu);
 107   // See if the mutex is locked by this thread.
 108   if (pthread_mutex_trylock (pmu))
 109     return 1;
 110 #if defined (PTHREAD_MUTEX_HAVE_M_COUNT)
 111   // On Linux we exploit knowledge of the implementation.
 112   int r = pmu->m_count == 1;
 113 #elif defined (PTHREAD_MUTEX_HAVE___M_COUNT)
 114   // In glibc 2.1, the first time the mutex is grabbed __m_count is
 115   // set to 0 and __m_owner is set to pthread_self().
 116   int r = ! pmu->__m_count;
 117 #else
 118   int r = mu->count == 0;
 119 #endif
 120   pthread_mutex_unlock (pmu);
 121   return r;
 122 }
 123
 124 //
 125 // Condition variables.
 126 //
 127
 128 inline void
 129 _Jv_CondInit (_Jv_ConditionVariable_t *cv)
 130 {
 131   pthread_cond_init (cv, 0);
 132 }
 133
 134 #ifndef LINUX_THREADS
 135
 136 // pthread_cond_destroy does nothing on Linux and it is a win to avoid
 137 // defining this macro.
 138
 139 #define _Jv_HaveCondDestroy
 140
 141 inline void
 142 _Jv_CondDestroy (_Jv_ConditionVariable_t *cv)
 143 {
 144   pthread_cond_destroy (cv);
 145 }
 146
 147 #endif /* LINUX_THREADS */
 148
 149 int _Jv_CondWait (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu,
 150                   jlong millis, jint nanos);
 151
 152 inline int
 153 _Jv_CondNotify (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu)
 154 {
 155   return _Jv_PthreadCheckMonitor (mu) || pthread_cond_signal (cv);
 156 }
 157
 158 inline int
 159 _Jv_CondNotifyAll (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu)
 160 {
 161   return _Jv_PthreadCheckMonitor (mu) || pthread_cond_broadcast (cv);
 162 }
 163
 164
 165 //
 166 // Mutexes.
 167 //
 168
 169 #ifdef RECURSIVE_MUTEX_IS_DEFAULT
 170 inline void
 171 _Jv_MutexInit (_Jv_Mutex_t *mu)
 172 {
 173   pthread_mutex_init (_Jv_PthreadGetMutex (mu), NULL);
 174 #ifdef PTHREAD_MUTEX_IS_STRUCT
 175   mu->count = 0;
 176 #endif
 177 }
 178 #else
 179 void _Jv_MutexInit (_Jv_Mutex_t *mu);
 180 #endif
 181
 182 #ifndef LINUX_THREADS
 183
 184 // pthread_mutex_destroy does nothing on Linux and it is a win to avoid
 185 // defining this macro.
 186
 187 #define _Jv_HaveMutexDestroy
 188
 189 #ifdef HAVE_RECURSIVE_MUTEX
 190
 191 inline void
 192 _Jv_MutexDestroy (_Jv_Mutex_t *mu)
 193 {
 194   pthread_mutex_destroy (_Jv_PthreadGetMutex (mu));
 195 }
 196
 197 #else /* HAVE_RECURSIVE_MUTEX */
 198
 199 extern void _Jv_MutexDestroy (_Jv_Mutex_t *mu);
 200
 201 #endif /* HAVE_RECURSIVE_MUTEX */
 202 #endif /* LINUX_THREADS */
 203
 204 #ifdef HAVE_RECURSIVE_MUTEX
 205
 206 inline int
 207 _Jv_MutexLock (_Jv_Mutex_t *mu)
 208 {
 209   int r = pthread_mutex_lock (_Jv_PthreadGetMutex (mu));
 210 #ifdef PTHREAD_MUTEX_IS_STRUCT
 211   if (! r)
 212     ++mu->count;
 213 #endif
 214   return r;
 215 }
 216
 217 inline int
 218 _Jv_MutexUnlock (_Jv_Mutex_t *mu)
 219 {
 220   int r = pthread_mutex_unlock (_Jv_PthreadGetMutex (mu));
 221 #ifdef PTHREAD_MUTEX_IS_STRUCT
 222   if (! r)
 223     --mu->count;
 224 #endif
 225   return r;
 226 }
 227
 228 #else /* HAVE_RECURSIVE_MUTEX */
 229
 230 extern int _Jv_MutexLock (_Jv_Mutex_t *mu);
 231 extern int _Jv_MutexUnlock (_Jv_Mutex_t *mu);
 232
 233 #endif /* HAVE_RECURSIVE_MUTEX */
 234
 235
 236 //
 237 // Thread creation and manipulation.
 238 //
 239
 240 void _Jv_InitThreads (void);
 241
 242 void _Jv_ThreadInitData (_Jv_Thread_t **data, java::lang::Thread *thread);
 243
 244 inline java::lang::Thread *
 245 _Jv_ThreadCurrent (void)
 246 {
 247   extern pthread_key_t _Jv_ThreadKey;
 248   return (java::lang::Thread *) pthread_getspecific (_Jv_ThreadKey);
 249 }
 250
 251 inline _Jv_Thread_t *
 252 _Jv_ThreadCurrentData (void)
 253 {
 254   extern pthread_key_t _Jv_ThreadDataKey;
 255   return (_Jv_Thread_t *) pthread_getspecific (_Jv_ThreadDataKey);
 256 }
 257
 258 inline void
 259 _Jv_ThreadYield (void)
 260 {
 261 #ifdef HAVE_SCHED_YIELD
 262   sched_yield ();
 263 #endif /* HAVE_SCHED_YIELD */
 264 }
 265
 266 void _Jv_ThreadSetPriority (_Jv_Thread_t *data, jint prio);
 267
 268 void _Jv_ThreadStart (java::lang::Thread *thread, _Jv_Thread_t *data,
 269                       _Jv_ThreadStartFunc *meth);
 270
 271 void _Jv_ThreadWait (void);
 272
 273 void _Jv_ThreadInterrupt (_Jv_Thread_t *data);
 274
 275 #endif /* __JV_POSIX_THREADS__ */