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))
83 #ifdef HAVE_RECURSIVE_MUTEX
89 if (millis == 0 && nanos == 0)
90 r = pthread_cond_wait (cv, pmu);
94 jlong m = millis + java::lang::System::currentTimeMillis ();
96 ts.tv_nsec = ((m % 1000) * 1000000) + nanos;
98 r = pthread_cond_timedwait (cv, pmu, &ts);
99 /* A timeout is a normal result. */
100 if (r && errno == ETIMEDOUT)
107 #ifndef RECURSIVE_MUTEX_IS_DEFAULT
110 _Jv_MutexInit (_Jv_Mutex_t *mu)
112 #ifdef HAVE_RECURSIVE_MUTEX
113 pthread_mutexattr_t *val = NULL;
115 #if defined (HAVE_PTHREAD_MUTEXATTR_SETTYPE)
116 pthread_mutexattr_t attr;
118 // If this is slow, then allocate it statically and only initialize
120 pthread_mutexattr_init (&attr);
121 pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE);
123 #elif defined (HAVE_PTHREAD_MUTEXATTR_SETKIND_NP)
124 pthread_mutexattr_t attr;
125 pthread_mutexattr_init (&attr);
126 pthread_mutexattr_setkind_np (&attr, PTHREAD_MUTEX_RECURSIVE_NP);
130 pthread_mutex_init (mu, val);
132 #if defined (HAVE_PTHREAD_MUTEXATTR_SETTYPE) || defined (HAVE_PTHREAD_MUTEXATTR_SETKIND_NP)
133 pthread_mutexattr_destroy (&attr);
136 #else /* HAVE_RECURSIVE_MUTEX */
138 // No recursive mutex, so simulate one.
139 pthread_mutex_init (&mu->mutex, NULL);
140 pthread_mutex_init (&mu->mutex2, NULL);
141 pthread_cond_init (&mu->cond, 0);
144 #endif /* HAVE_RECURSIVE_MUTEX */
147 #endif /* not RECURSIVE_MUTEX_IS_DEFAULT */
149 #if ! defined (LINUX_THREADS) && ! defined (HAVE_RECURSIVE_MUTEX)
152 _Jv_MutexDestroy (_Jv_Mutex_t *mu)
154 pthread_mutex_destroy (&mu->mutex);
155 pthread_mutex_destroy (&mu->mutex2);
156 pthread_cond_destroy (&mu->cond);
160 _Jv_MutexLock (_Jv_Mutex_t *mu)
162 if (pthread_mutex_lock (&mu->mutex))
169 mu->thread = pthread_self ();
171 pthread_mutex_lock (&mu->mutex2);
174 else if (pthread_self () == mu->thread)
176 // Already have the lock.
182 // Try to acquire the lock.
183 pthread_cond_wait (&mu->cond, &mu->mutex);
186 pthread_mutex_unlock (&mu->mutex);
191 _Jv_MutexUnlock (_Jv_Mutex_t *mu)
193 if (pthread_mutex_lock (&mu->mutex))
196 if (mu->count == 0 || pthread_self () != mu->thread)
203 pthread_mutex_unlock (&mu->mutex2);
204 pthread_cond_signal (&mu->cond);
207 pthread_mutex_unlock (&mu->mutex);
211 #endif /* not LINUX_THREADS and not HAVE_RECURSIVE_MUTEX */
220 _Jv_InitThreads (void)
222 pthread_key_create (&_Jv_ThreadKey, NULL);
223 pthread_mutex_init (&daemon_mutex, NULL);
224 pthread_cond_init (&daemon_cond, 0);
225 non_daemon_count = 0;
227 // Arrange for the interrupt signal to interrupt system calls.
228 struct sigaction act;
229 act.sa_handler = handle_intr;
230 sigemptyset (&act.sa_mask);
232 sigaction (INTR, &act, NULL);
234 // Arrange for SIGINT to be blocked to all threads. It is only
235 // deliverable to the master thread.
238 sigaddset (&mask, SIGINT);
239 pthread_sigmask (SIG_BLOCK, &mask, NULL);
243 _Jv_ThreadInitData (_Jv_Thread_t **data, java::lang::Thread *)
245 _Jv_Thread_t *info = new _Jv_Thread_t;
248 info->exception = NULL;
250 // FIXME register a finalizer for INFO here.
251 // FIXME also must mark INFO somehow.
257 _Jv_ThreadSetPriority (_Jv_Thread_t *data, jint prio)
259 if (data->flags & FLAG_START)
261 struct sched_param param;
263 param.sched_priority = prio;
264 pthread_setschedparam (data->thread, SCHED_RR, ¶m);
269 // This is called as a cleanup handler when a thread is exiting. We
270 // use it to throw the requested exception. It's entirely possible
271 // that this approach is doomed to failure, in which case we'll need
272 // to adopt some alternate. For instance, use a signal to implement
275 throw_cleanup (void *data)
277 _Jv_Thread_t *td = (_Jv_Thread_t *) data;
278 _Jv_Throw ((java::lang::Throwable *) td->exception);
282 _Jv_ThreadCancel (_Jv_Thread_t *data, void *error)
284 data->exception = error;
285 pthread_cancel (data->thread);
288 // This function is called when a thread is started. We don't arrange
289 // to call the `run' method directly, because this function must
292 really_start (void *x)
294 struct starter *info = (struct starter *) x;
296 pthread_cleanup_push (throw_cleanup, info->data);
297 pthread_setspecific (_Jv_ThreadKey, info->object);
298 info->method (info->object);
299 pthread_cleanup_pop (0);
301 if (! (info->data->flags & FLAG_DAEMON))
303 pthread_mutex_lock (&daemon_mutex);
305 if (! non_daemon_count)
306 pthread_cond_signal (&daemon_cond);
307 pthread_mutex_unlock (&daemon_mutex);
314 _Jv_ThreadStart (java::lang::Thread *thread, _Jv_Thread_t *data,
315 _Jv_ThreadStartFunc *meth)
317 struct sched_param param;
319 struct starter *info;
321 if (data->flags & FLAG_START)
323 data->flags |= FLAG_START;
325 param.sched_priority = thread->getPriority();
327 pthread_attr_init (&attr);
328 pthread_attr_setschedparam (&attr, ¶m);
330 // FIXME: handle marking the info object for GC.
331 info = (struct starter *) _Jv_AllocBytes (sizeof (struct starter));
333 info->object = thread;
336 if (! thread->isDaemon())
338 pthread_mutex_lock (&daemon_mutex);
340 pthread_mutex_unlock (&daemon_mutex);
343 data->flags |= FLAG_DAEMON;
344 pthread_create (&data->thread, &attr, really_start, (void *) info);
346 pthread_attr_destroy (&attr);
350 _Jv_ThreadWait (void)
352 // Arrange for SIGINT to be delivered to the master thread.
355 sigaddset (&mask, SIGINT);
356 pthread_sigmask (SIG_UNBLOCK, &mask, NULL);
358 pthread_mutex_lock (&daemon_mutex);
359 if (non_daemon_count)
360 pthread_cond_wait (&daemon_cond, &daemon_mutex);
361 pthread_mutex_unlock (&daemon_mutex);
365 _Jv_ThreadInterrupt (_Jv_Thread_t *data)
367 pthread_kill (data->thread, INTR);