1 // posix-threads.cc - interface between libjava and POSIX threads.
3 /* Copyright (C) 1998, 1999 Cygnus Solutions
5 This file is part of libgcj.
7 This software is copyrighted work licensed under the terms of the
8 Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
12 // * Document signal handling limitations
16 // If we're using the Boehm GC, then we need to override some of the
17 // thread primitives. This is fairly gross.
21 #include <boehm-config.h>
24 #endif /* HAVE_BOEHM_GC */
33 #include <java/lang/Thread.h>
34 #include <java/lang/System.h>
36 // This is used to implement thread startup.
39 _Jv_ThreadStartFunc *method;
40 java::lang::Thread *object;
44 // This is the key used to map from the POSIX thread value back to the
45 // Java object representing the thread. The key is global to all
46 // threads, so it is ok to make it a global here.
47 pthread_key_t _Jv_ThreadKey;
49 // We keep a count of all non-daemon threads which are running. When
50 // this reaches zero, _Jv_ThreadWait returns.
51 static pthread_mutex_t daemon_mutex;
52 static pthread_cond_t daemon_cond;
53 static int non_daemon_count;
55 // The signal to use when interrupting a thread.
57 // LinuxThreads usurps both SIGUSR1 and SIGUSR2.
59 #else /* LINUX_THREADS */
61 #endif /* LINUX_THREADS */
64 // These are the flags that can appear in _Jv_Thread_t.
68 #define FLAG_START 0x01
70 #define FLAG_DAEMON 0x02
75 _Jv_CondWait (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu,
76 jlong millis, jint nanos)
78 if (_Jv_PthreadCheckMonitor (mu))
82 pthread_mutex_t *pmu = _Jv_PthreadGetMutex (mu);
84 if (millis == 0 && nanos == 0)
85 r = pthread_cond_wait (cv, pmu);
89 jlong m = millis + java::lang::System::currentTimeMillis ();
91 ts.tv_nsec = ((m % 1000) * 1000000) + nanos;
93 r = pthread_cond_timedwait (cv, pmu, &ts);
94 /* A timeout is a normal result. */
95 if (r && errno == ETIMEDOUT)
102 #ifndef RECURSIVE_MUTEX_IS_DEFAULT
105 _Jv_MutexInit (_Jv_Mutex_t *mu)
107 #ifdef HAVE_RECURSIVE_MUTEX
108 pthread_mutexattr_t *val = NULL;
110 #if defined (HAVE_PTHREAD_MUTEXATTR_SETTYPE)
111 pthread_mutexattr_t attr;
113 // If this is slow, then allocate it statically and only initialize
115 pthread_mutexattr_init (&attr);
116 pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE);
118 #elif defined (HAVE_PTHREAD_MUTEXATTR_SETKIND_NP)
119 pthread_mutexattr_t attr;
120 pthread_mutexattr_init (&attr);
121 pthread_mutexattr_setkind_np (&attr, PTHREAD_MUTEX_RECURSIVE_NP);
125 pthread_mutex_init (mu, val);
127 #if defined (HAVE_PTHREAD_MUTEXATTR_SETTYPE) || defined (HAVE_PTHREAD_MUTEXATTR_SETKIND_NP)
128 pthread_mutexattr_destroy (&attr);
131 #else /* HAVE_RECURSIVE_MUTEX */
133 // No recursive mutex, so simulate one.
134 pthread_mutex_init (&mu->mutex, NULL);
135 pthread_mutex_init (&mu->mutex2, NULL);
136 pthread_cond_init (&mu->cond, 0);
139 #endif /* HAVE_RECURSIVE_MUTEX */
142 #endif /* not RECURSIVE_MUTEX_IS_DEFAULT */
144 #if ! defined (LINUX_THREADS) && ! defined (HAVE_RECURSIVE_MUTEX)
147 _Jv_MutexDestroy (_Jv_Mutex_t *mu)
149 pthread_mutex_destroy (&mu->mutex);
150 pthread_mutex_destroy (&mu->mutex2);
151 pthread_cond_destroy (&mu->cond);
155 _Jv_MutexLock (_Jv_Mutex_t *mu)
157 if (pthread_mutex_lock (&mu->mutex))
164 mu->thread = pthread_self ();
166 pthread_mutex_lock (&mu->mutex2);
169 else if (pthread_self () == mu->thread)
171 // Already have the lock.
177 // Try to acquire the lock.
178 pthread_cond_wait (&mu->cond, &mu->mutex);
181 pthread_mutex_unlock (&mu->mutex);
186 _Jv_MutexUnlock (_Jv_Mutex_t *mu)
188 if (pthread_mutex_lock (&mu->mutex))
191 if (mu->count == 0 || pthread_self () != mu->thread)
198 pthread_mutex_unlock (&mu->mutex2);
199 pthread_cond_signal (&mu->cond);
202 pthread_mutex_unlock (&mu->mutex);
206 #endif /* not LINUX_THREADS and not HAVE_RECURSIVE_MUTEX */
215 _Jv_InitThreads (void)
217 pthread_key_create (&_Jv_ThreadKey, NULL);
218 pthread_mutex_init (&daemon_mutex, NULL);
219 pthread_cond_init (&daemon_cond, 0);
220 non_daemon_count = 0;
222 // Arrange for the interrupt signal to interrupt system calls.
223 struct sigaction act;
224 act.sa_handler = handle_intr;
225 sigemptyset (&act.sa_mask);
227 sigaction (INTR, &act, NULL);
229 // Arrange for SIGINT to be blocked to all threads. It is only
230 // deliverable to the master thread.
233 sigaddset (&mask, SIGINT);
234 pthread_sigmask (SIG_BLOCK, &mask, NULL);
238 _Jv_ThreadInitData (_Jv_Thread_t **data, java::lang::Thread *)
240 _Jv_Thread_t *info = new _Jv_Thread_t;
243 info->exception = NULL;
245 // FIXME register a finalizer for INFO here.
246 // FIXME also must mark INFO somehow.
252 _Jv_ThreadSetPriority (_Jv_Thread_t *data, jint prio)
254 if (data->flags & FLAG_START)
256 struct sched_param param;
258 param.sched_priority = prio;
259 pthread_setschedparam (data->thread, SCHED_RR, ¶m);
264 // This is called as a cleanup handler when a thread is exiting. We
265 // use it to throw the requested exception. It's entirely possible
266 // that this approach is doomed to failure, in which case we'll need
267 // to adopt some alternate. For instance, use a signal to implement
270 throw_cleanup (void *data)
272 _Jv_Thread_t *td = (_Jv_Thread_t *) data;
273 _Jv_Throw ((java::lang::Throwable *) td->exception);
277 _Jv_ThreadCancel (_Jv_Thread_t *data, void *error)
279 data->exception = error;
280 pthread_cancel (data->thread);
283 // This function is called when a thread is started. We don't arrange
284 // to call the `run' method directly, because this function must
287 really_start (void *x)
289 struct starter *info = (struct starter *) x;
291 pthread_cleanup_push (throw_cleanup, info->data);
292 pthread_setspecific (_Jv_ThreadKey, info->object);
293 info->method (info->object);
294 pthread_cleanup_pop (0);
296 if (! (info->data->flags & FLAG_DAEMON))
298 pthread_mutex_lock (&daemon_mutex);
300 if (! non_daemon_count)
301 pthread_cond_signal (&daemon_cond);
302 pthread_mutex_unlock (&daemon_mutex);
309 _Jv_ThreadStart (java::lang::Thread *thread, _Jv_Thread_t *data,
310 _Jv_ThreadStartFunc *meth)
312 struct sched_param param;
314 struct starter *info;
316 if (data->flags & FLAG_START)
318 data->flags |= FLAG_START;
320 param.sched_priority = thread->getPriority();
322 pthread_attr_init (&attr);
323 pthread_attr_setschedparam (&attr, ¶m);
325 // FIXME: handle marking the info object for GC.
326 info = (struct starter *) _Jv_AllocBytes (sizeof (struct starter));
328 info->object = thread;
331 if (! thread->isDaemon())
333 pthread_mutex_lock (&daemon_mutex);
335 pthread_mutex_unlock (&daemon_mutex);
338 data->flags |= FLAG_DAEMON;
339 pthread_create (&data->thread, &attr, really_start, (void *) info);
341 pthread_attr_destroy (&attr);
345 _Jv_ThreadWait (void)
347 // Arrange for SIGINT to be delivered to the master thread.
350 sigaddset (&mask, SIGINT);
351 pthread_sigmask (SIG_UNBLOCK, &mask, NULL);
353 pthread_mutex_lock (&daemon_mutex);
354 if (non_daemon_count)
355 pthread_cond_wait (&daemon_cond, &daemon_mutex);
356 pthread_mutex_unlock (&daemon_mutex);
360 _Jv_ThreadInterrupt (_Jv_Thread_t *data)
362 pthread_kill (data->thread, INTR);