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 */
32 #include <java/lang/Thread.h>
33 #include <java/lang/System.h>
35 // This is used to implement thread startup.
38 _Jv_ThreadStartFunc *method;
39 java::lang::Thread *object;
43 // This is the key used to map from the POSIX thread value back to the
44 // Java object representing the thread. The key is global to all
45 // threads, so it is ok to make it a global here.
46 pthread_key_t _Jv_ThreadKey;
48 // We keep a count of all non-daemon threads which are running. When
49 // this reaches zero, _Jv_ThreadWait returns.
50 static pthread_mutex_t daemon_mutex;
51 static pthread_cond_t daemon_cond;
52 static int non_daemon_count;
54 // The signal to use when interrupting a thread.
56 // LinuxThreads usurps both SIGUSR1 and SIGUSR2.
58 #else /* LINUX_THREADS */
60 #endif /* LINUX_THREADS */
63 // These are the flags that can appear in _Jv_Thread_t.
67 #define FLAG_START 0x01
69 #define FLAG_DAEMON 0x02
74 _Jv_CondWait (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu,
75 jlong millis, jint nanos)
79 #ifdef HAVE_RECURSIVE_MUTEX
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)
101 #ifndef RECURSIVE_MUTEX_IS_DEFAULT
104 _Jv_MutexInit (_Jv_Mutex_t *mu)
106 #ifdef HAVE_RECURSIVE_MUTEX
107 pthread_mutexattr_t *val = NULL;
109 #if defined (HAVE_PTHREAD_MUTEXATTR_SETTYPE)
110 pthread_mutexattr_t attr;
112 // If this is slow, then allocate it statically and only initialize
114 pthread_mutexattr_init (&attr);
115 pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE);
117 #elif defined (HAVE_PTHREAD_MUTEXATTR_SETKIND_NP)
118 pthread_mutexattr_t attr;
119 pthread_mutexattr_init (&attr);
120 pthread_mutexattr_setkind_np (&attr, PTHREAD_MUTEX_RECURSIVE_NP);
124 pthread_mutex_init (mu, val);
126 #if defined (HAVE_PTHREAD_MUTEXATTR_SETTYPE) || defined (HAVE_PTHREAD_MUTEXATTR_SETKIND_NP)
127 pthread_mutexattr_destroy (&attr);
130 #else /* HAVE_RECURSIVE_MUTEX */
132 // No recursive mutex, so simulate one.
133 pthread_mutex_init (&mu->mutex, NULL);
134 pthread_mutex_init (&mu->mutex2, NULL);
135 pthread_cond_init (&mu->cond, 0);
138 #endif /* HAVE_RECURSIVE_MUTEX */
141 #endif /* not RECURSIVE_MUTEX_IS_DEFAULT */
143 #if ! defined (LINUX_THREADS) && ! defined (HAVE_RECURSIVE_MUTEX)
146 _Jv_MutexDestroy (_Jv_Mutex_t *mu)
148 pthread_mutex_destroy (&mu->mutex);
149 pthread_mutex_destroy (&mu->mutex2);
150 pthread_cond_destroy (&mu->cond);
154 _Jv_MutexLock (_Jv_Mutex_t *mu)
156 if (pthread_mutex_lock (&mu->mutex))
163 mu->thread = pthread_self ();
165 pthread_mutex_lock (&mu->mutex2);
168 else if (pthread_self () == mu->thread)
170 // Already have the lock.
176 // Try to acquire the lock.
177 pthread_cond_wait (&mu->cond, &mu->mutex);
180 pthread_mutex_unlock (&mu->mutex);
185 _Jv_MutexUnlock (_Jv_Mutex_t *mu)
187 if (pthread_mutex_lock (&mu->mutex))
190 if (mu->count == 0 || pthread_self () != mu->thread)
197 pthread_mutex_unlock (&mu->mutex2);
198 pthread_cond_signal (&mu->cond);
201 pthread_mutex_unlock (&mu->mutex);
205 #endif /* not LINUX_THREADS and not HAVE_RECURSIVE_MUTEX */
214 _Jv_InitThreads (void)
216 pthread_key_create (&_Jv_ThreadKey, NULL);
217 pthread_mutex_init (&daemon_mutex, NULL);
218 pthread_cond_init (&daemon_cond, 0);
219 non_daemon_count = 0;
221 // Arrange for the interrupt signal to interrupt system calls.
222 struct sigaction act;
223 act.sa_handler = handle_intr;
224 sigemptyset (&act.sa_mask);
226 sigaction (INTR, &act, NULL);
228 // Arrange for SIGINT to be blocked to all threads. It is only
229 // deliverable to the master thread.
232 sigaddset (&mask, SIGINT);
233 pthread_sigmask (SIG_BLOCK, &mask, NULL);
237 _Jv_ThreadInitData (_Jv_Thread_t **data, java::lang::Thread *)
239 _Jv_Thread_t *info = new _Jv_Thread_t;
242 info->exception = NULL;
244 // FIXME register a finalizer for INFO here.
245 // FIXME also must mark INFO somehow.
251 _Jv_ThreadSetPriority (_Jv_Thread_t *data, jint prio)
253 if (data->flags & FLAG_START)
255 struct sched_param param;
257 param.sched_priority = prio;
258 pthread_setschedparam (data->thread, SCHED_RR, ¶m);
263 // This is called as a cleanup handler when a thread is exiting. We
264 // use it to throw the requested exception. It's entirely possible
265 // that this approach is doomed to failure, in which case we'll need
266 // to adopt some alternate. For instance, use a signal to implement
269 throw_cleanup (void *data)
271 _Jv_Thread_t *td = (_Jv_Thread_t *) data;
272 _Jv_Throw ((java::lang::Throwable *) td->exception);
276 _Jv_ThreadCancel (_Jv_Thread_t *data, void *error)
278 data->exception = error;
279 pthread_cancel (data->thread);
282 // This function is called when a thread is started. We don't arrange
283 // to call the `run' method directly, because this function must
286 really_start (void *x)
288 struct starter *info = (struct starter *) x;
290 pthread_cleanup_push (throw_cleanup, info->data);
291 pthread_setspecific (_Jv_ThreadKey, info->object);
292 info->method (info->object);
293 pthread_cleanup_pop (0);
295 if (! (info->data->flags & FLAG_DAEMON))
297 pthread_mutex_lock (&daemon_mutex);
299 if (! non_daemon_count)
300 pthread_cond_signal (&daemon_cond);
301 pthread_mutex_unlock (&daemon_mutex);
308 _Jv_ThreadStart (java::lang::Thread *thread, _Jv_Thread_t *data,
309 _Jv_ThreadStartFunc *meth)
311 struct sched_param param;
313 struct starter *info;
315 if (data->flags & FLAG_START)
317 data->flags |= FLAG_START;
319 param.sched_priority = thread->getPriority();
321 pthread_attr_init (&attr);
322 pthread_attr_setschedparam (&attr, ¶m);
324 // FIXME: handle marking the info object for GC.
325 info = (struct starter *) _Jv_AllocBytes (sizeof (struct starter));
327 info->object = thread;
330 if (! thread->isDaemon())
332 pthread_mutex_lock (&daemon_mutex);
334 pthread_mutex_unlock (&daemon_mutex);
337 data->flags |= FLAG_DAEMON;
338 pthread_create (&data->thread, &attr, really_start, (void *) info);
340 pthread_attr_destroy (&attr);
344 _Jv_ThreadWait (void)
346 // Arrange for SIGINT to be delivered to the master thread.
349 sigaddset (&mask, SIGINT);
350 pthread_sigmask (SIG_UNBLOCK, &mask, NULL);
352 pthread_mutex_lock (&daemon_mutex);
353 if (non_daemon_count)
354 pthread_cond_wait (&daemon_cond, &daemon_mutex);
355 pthread_mutex_unlock (&daemon_mutex);
359 _Jv_ThreadInterrupt (_Jv_Thread_t *data)
361 pthread_kill (data->thread, INTR);