// posix-threads.cc - interface between libjava and POSIX threads.
-/* Copyright (C) 1998, 1999 Cygnus Solutions
+/* Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation
This file is part of libgcj.
// If we're using the Boehm GC, then we need to override some of the
// thread primitives. This is fairly gross.
#ifdef HAVE_BOEHM_GC
-extern "C"
-{
-#include <gcconfig.h>
#include <gc.h>
-};
#endif /* HAVE_BOEHM_GC */
#include <stdlib.h>
#include <time.h>
#include <signal.h>
#include <errno.h>
+#include <limits.h>
#include <gcj/cni.h>
#include <jvm.h>
#include <java/lang/Thread.h>
#include <java/lang/System.h>
+#include <java/lang/Long.h>
+#include <java/lang/OutOfMemoryError.h>
// This is used to implement thread startup.
struct starter
{
_Jv_ThreadStartFunc *method;
- java::lang::Thread *object;
_Jv_Thread_t *data;
};
// The signal to use when interrupting a thread.
#ifdef LINUX_THREADS
- // LinuxThreads usurps both SIGUSR1 and SIGUSR2.
+ // LinuxThreads (prior to glibc 2.1) usurps both SIGUSR1 and SIGUSR2.
# define INTR SIGHUP
#else /* LINUX_THREADS */
# define INTR SIGUSR2
#define FLAG_START 0x01
// Thread is daemon.
#define FLAG_DAEMON 0x02
-// Thread was interrupted by _Jv_ThreadInterrupt.
-#define FLAG_INTERRUPTED 0x04
\f
+// Wait for the condition variable "CV" to be notified.
+// Return values:
+// 0: the condition was notified, or the timeout expired.
+// _JV_NOT_OWNER: the thread does not own the mutex "MU".
+// _JV_INTERRUPTED: the thread was interrupted. Its interrupted flag is set.
int
_Jv_CondWait (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu,
jlong millis, jint nanos)
{
- if (_Jv_PthreadCheckMonitor (mu))
- return 1;
+ pthread_t self = pthread_self();
+ if (mu->owner != self)
+ return _JV_NOT_OWNER;
- int r;
- pthread_mutex_t *pmu = _Jv_PthreadGetMutex (mu);
- struct timespec ts;
- jlong m, m2, startTime;
- bool done_sleeping = false;
+ struct timespec ts;
+ jlong m, startTime;
- if (millis == 0 && nanos == 0)
- r = pthread_cond_wait (cv, pmu);
- else
+ if (millis > 0 || nanos > 0)
{
startTime = java::lang::System::currentTimeMillis();
m = millis + startTime;
+ ts.tv_sec = m / 1000;
+ ts.tv_nsec = ((m % 1000) * 1000000) + nanos;
+ }
+
+ _Jv_Thread_t *current = _Jv_ThreadCurrentData ();
+ java::lang::Thread *current_obj = _Jv_ThreadCurrent ();
+
+ pthread_mutex_lock (¤t->wait_mutex);
+
+ // Now that we hold the wait mutex, check if this thread has been
+ // interrupted already.
+ if (current_obj->interrupt_flag)
+ {
+ pthread_mutex_unlock (¤t->wait_mutex);
+ return _JV_INTERRUPTED;
+ }
- do
- {
- ts.tv_sec = m / 1000;
- ts.tv_nsec = ((m % 1000) * 1000000) + nanos;
+ // Add this thread to the cv's wait set.
+ current->next = NULL;
- r = pthread_cond_timedwait (cv, pmu, &ts);
+ if (cv->first == NULL)
+ cv->first = current;
+ else
+ for (_Jv_Thread_t *t = cv->first;; t = t->next)
+ {
+ if (t->next == NULL)
+ {
+ t->next = current;
+ break;
+ }
+ }
+
+ // Record the current lock depth, so it can be restored when we re-aquire it.
+ int count = mu->count;
+
+ // Release the monitor mutex.
+ mu->count = 0;
+ mu->owner = 0;
+ pthread_mutex_unlock (&mu->mutex);
+
+ int r = 0;
+ bool done_sleeping = false;
- if (r == EINTR)
+ while (! done_sleeping)
+ {
+ if (millis == 0 && nanos == 0)
+ r = pthread_cond_wait (¤t->wait_cond, ¤t->wait_mutex);
+ else
+ r = pthread_cond_timedwait (¤t->wait_cond, ¤t->wait_mutex,
+ &ts);
+
+ // In older glibc's (prior to 2.1.3), the cond_wait functions may
+ // spuriously wake up on a signal. Catch that here.
+ if (r != EINTR)
+ done_sleeping = true;
+ }
+
+ // Check for an interrupt *before* releasing the wait mutex.
+ jboolean interrupted = current_obj->interrupt_flag;
+
+ pthread_mutex_unlock (¤t->wait_mutex);
+
+ // Reaquire the monitor mutex, and restore the lock count.
+ pthread_mutex_lock (&mu->mutex);
+ mu->owner = self;
+ mu->count = count;
+
+ // If we were interrupted, or if a timeout occured, remove ourself from
+ // the cv wait list now. (If we were notified normally, notify() will have
+ // already taken care of this)
+ if (r == ETIMEDOUT || interrupted)
+ {
+ _Jv_Thread_t *prev = NULL;
+ for (_Jv_Thread_t *t = cv->first; t != NULL; t = t->next)
+ {
+ if (t == current)
{
- /* We were interrupted by a signal. Either this is
- because we were interrupted intentionally (i.e. by
- Thread.interrupt()) or by the GC if it is
- signal-based. */
- _Jv_Thread_t *current = _Jv_ThreadCurrentData();
- if (current->flags & FLAG_INTERRUPTED)
- {
- current->flags &= ~(FLAG_INTERRUPTED);
- done_sleeping = true;
- }
+ if (prev != NULL)
+ prev->next = t->next;
else
- {
- /* We were woken up by the GC or another signal. */
- m2 = java::lang::System::currentTimeMillis ();
- if (m2 >= m)
- {
- r = 0;
- done_sleeping = true;
- }
- }
- }
- else if (r == ETIMEDOUT)
- {
- /* A timeout is a normal result. */
- r = 0;
- done_sleeping = true;
+ cv->first = t->next;
+ t->next = NULL;
+ break;
}
- else
- done_sleeping = true;
+ prev = t;
}
- while (! done_sleeping);
+ if (interrupted)
+ return _JV_INTERRUPTED;
}
-
- return r != 0;
+
+ return 0;
}
-#ifndef RECURSIVE_MUTEX_IS_DEFAULT
-
-void
-_Jv_MutexInit (_Jv_Mutex_t *mu)
+int
+_Jv_CondNotify (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu)
{
-#ifdef HAVE_RECURSIVE_MUTEX
- pthread_mutexattr_t *val = NULL;
-
-#if defined (HAVE_PTHREAD_MUTEXATTR_SETTYPE)
- pthread_mutexattr_t attr;
-
- // If this is slow, then allocate it statically and only initialize
- // it once.
- pthread_mutexattr_init (&attr);
- pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE);
- val = &attr;
-#elif defined (HAVE_PTHREAD_MUTEXATTR_SETKIND_NP)
- pthread_mutexattr_t attr;
- pthread_mutexattr_init (&attr);
- pthread_mutexattr_setkind_np (&attr, PTHREAD_MUTEX_RECURSIVE_NP);
- val = &attr;
-#endif
-
- pthread_mutex_init (_Jv_PthreadGetMutex (mu), val);
-#ifdef PTHREAD_MUTEX_IS_STRUCT
- mu->count = 0;
-#endif
-
-#if defined (HAVE_PTHREAD_MUTEXATTR_SETTYPE) || defined (HAVE_PTHREAD_MUTEXATTR_SETKIND_NP)
- pthread_mutexattr_destroy (&attr);
-#endif
-
-#else /* HAVE_RECURSIVE_MUTEX */
+ if (_Jv_PthreadCheckMonitor (mu))
+ return _JV_NOT_OWNER;
- // No recursive mutex, so simulate one.
- pthread_mutex_init (&mu->mutex, NULL);
- pthread_mutex_init (&mu->mutex2, NULL);
- pthread_cond_init (&mu->cond, 0);
- mu->count = 0;
+ _Jv_Thread_t *target;
+ _Jv_Thread_t *prev = NULL;
-#endif /* HAVE_RECURSIVE_MUTEX */
-}
+ for (target = cv->first; target != NULL; target = target->next)
+ {
+ pthread_mutex_lock (&target->wait_mutex);
+
+ if (target->thread_obj->interrupt_flag)
+ {
+ // Don't notify a thread that has already been interrupted.
+ pthread_mutex_unlock (&target->wait_mutex);
+ prev = target;
+ continue;
+ }
-#endif /* not RECURSIVE_MUTEX_IS_DEFAULT */
+ pthread_cond_signal (&target->wait_cond);
+ pthread_mutex_unlock (&target->wait_mutex);
-#if ! defined (LINUX_THREADS) && ! defined (HAVE_RECURSIVE_MUTEX)
+ // Two concurrent notify() calls must not be delivered to the same
+ // thread, so remove the target thread from the cv wait list now.
+ if (prev == NULL)
+ cv->first = target->next;
+ else
+ prev->next = target->next;
+
+ target->next = NULL;
+
+ break;
+ }
-void
-_Jv_MutexDestroy (_Jv_Mutex_t *mu)
-{
- pthread_mutex_destroy (&mu->mutex);
- pthread_mutex_destroy (&mu->mutex2);
- pthread_cond_destroy (&mu->cond);
+ return 0;
}
int
-_Jv_MutexLock (_Jv_Mutex_t *mu)
+_Jv_CondNotifyAll (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu)
{
- if (pthread_mutex_lock (&mu->mutex))
- return -1;
- while (1)
+ if (_Jv_PthreadCheckMonitor (mu))
+ return _JV_NOT_OWNER;
+
+ _Jv_Thread_t *target;
+ _Jv_Thread_t *prev = NULL;
+
+ for (target = cv->first; target != NULL; target = target->next)
{
- if (mu->count == 0)
- {
- // Grab the lock.
- mu->thread = pthread_self ();
- mu->count = 1;
- pthread_mutex_lock (&mu->mutex2);
- break;
- }
- else if (pthread_self () == mu->thread)
- {
- // Already have the lock.
- mu->count += 1;
- break;
- }
- else
- {
- // Try to acquire the lock.
- pthread_cond_wait (&mu->cond, &mu->mutex);
- }
+ pthread_mutex_lock (&target->wait_mutex);
+ pthread_cond_signal (&target->wait_cond);
+ pthread_mutex_unlock (&target->wait_mutex);
+
+ if (prev != NULL)
+ prev->next = NULL;
+ prev = target;
}
- pthread_mutex_unlock (&mu->mutex);
+ if (prev != NULL)
+ prev->next = NULL;
+
+ cv->first = NULL;
+
return 0;
}
-int
-_Jv_MutexUnlock (_Jv_Mutex_t *mu)
+void
+_Jv_ThreadInterrupt (_Jv_Thread_t *data)
{
- if (pthread_mutex_lock (&mu->mutex))
- return -1;
- int r = 0;
- if (mu->count == 0 || pthread_self () != mu->thread)
- r = -1;
- else
- {
- mu->count -= 1;
- if (! mu->count)
- {
- pthread_mutex_unlock (&mu->mutex2);
- pthread_cond_signal (&mu->cond);
- }
- }
- pthread_mutex_unlock (&mu->mutex);
- return r;
+ pthread_mutex_lock (&data->wait_mutex);
+
+ // Set the thread's interrupted flag *after* aquiring its wait_mutex. This
+ // ensures that there are no races with the interrupt flag being set after
+ // the waiting thread checks it and before pthread_cond_wait is entered.
+ data->thread_obj->interrupt_flag = true;
+
+ // Interrupt blocking system calls using a signal.
+// pthread_kill (data->thread, INTR);
+
+ pthread_cond_signal (&data->wait_cond);
+
+ pthread_mutex_unlock (&data->wait_mutex);
}
-#endif /* not LINUX_THREADS and not HAVE_RECURSIVE_MUTEX */
-
static void
handle_intr (int)
{
sigemptyset (&act.sa_mask);
act.sa_flags = 0;
sigaction (INTR, &act, NULL);
-
- // Arrange for SIGINT to be blocked to all threads. It is only
- // deliverable to the master thread.
- sigset_t mask;
- sigemptyset (&mask);
- sigaddset (&mask, SIGINT);
- pthread_sigmask (SIG_BLOCK, &mask, NULL);
}
-void
-_Jv_ThreadInitData (_Jv_Thread_t **data, java::lang::Thread *)
+_Jv_Thread_t *
+_Jv_ThreadInitData (java::lang::Thread *obj)
{
- _Jv_Thread_t *info = new _Jv_Thread_t;
+ _Jv_Thread_t *data = (_Jv_Thread_t *) _Jv_Malloc (sizeof (_Jv_Thread_t));
+ data->flags = 0;
+ data->thread_obj = obj;
- info->flags = 0;
+ pthread_mutex_init (&data->wait_mutex, NULL);
+ pthread_cond_init (&data->wait_cond, NULL);
- // FIXME register a finalizer for INFO here.
- // FIXME also must mark INFO somehow.
+ return data;
+}
- *data = info;
+void
+_Jv_ThreadDestroyData (_Jv_Thread_t *data)
+{
+ pthread_mutex_destroy (&data->wait_mutex);
+ pthread_cond_destroy (&data->wait_cond);
+ _Jv_Free ((void *)data);
}
void
}
}
+void
+_Jv_ThreadRegister (_Jv_Thread_t *data)
+{
+ pthread_setspecific (_Jv_ThreadKey, data->thread_obj);
+ pthread_setspecific (_Jv_ThreadDataKey, data);
+
+ // glibc 2.1.3 doesn't set the value of `thread' until after start_routine
+ // is called. Since it may need to be accessed from the new thread, work
+ // around the potential race here by explicitly setting it again.
+ data->thread = pthread_self ();
+
+# ifdef SLOW_PTHREAD_SELF
+ // Clear all self cache slots that might be needed by this thread.
+ int dummy;
+ int low_index = SC_INDEX(&dummy) + SC_CLEAR_MIN;
+ int high_index = SC_INDEX(&dummy) + SC_CLEAR_MAX;
+ for (int i = low_index; i <= high_index; ++i)
+ {
+ int current_index = i;
+ if (current_index < 0)
+ current_index += SELF_CACHE_SIZE;
+ if (current_index >= SELF_CACHE_SIZE)
+ current_index -= SELF_CACHE_SIZE;
+ _Jv_self_cache[current_index].high_sp_bits = BAD_HIGH_SP_VALUE;
+ }
+# endif
+}
+
+void
+_Jv_ThreadUnRegister ()
+{
+ pthread_setspecific (_Jv_ThreadKey, NULL);
+ pthread_setspecific (_Jv_ThreadDataKey, NULL);
+}
+
// This function is called when a thread is started. We don't arrange
// to call the `run' method directly, because this function must
// return a value.
{
struct starter *info = (struct starter *) x;
- pthread_setspecific (_Jv_ThreadKey, info->object);
- pthread_setspecific (_Jv_ThreadDataKey, info->data);
- info->method (info->object);
+ _Jv_ThreadRegister (info->data);
+
+ info->method (info->data->thread_obj);
if (! (info->data->flags & FLAG_DAEMON))
{
pthread_attr_init (&attr);
pthread_attr_setschedparam (&attr, ¶m);
+ pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
- // FIXME: handle marking the info object for GC.
info = (struct starter *) _Jv_AllocBytes (sizeof (struct starter));
info->method = meth;
- info->object = thread;
info->data = data;
if (! thread->isDaemon())
}
else
data->flags |= FLAG_DAEMON;
- pthread_create (&data->thread, &attr, really_start, (void *) info);
-
+ int r = pthread_create (&data->thread, &attr, really_start, (void *) info);
+
pthread_attr_destroy (&attr);
+
+ if (r)
+ {
+ const char* msg = "Cannot create additional threads";
+ throw new java::lang::OutOfMemoryError (JvNewStringUTF (msg));
+ }
}
void
_Jv_ThreadWait (void)
{
- // Arrange for SIGINT to be delivered to the master thread.
- sigset_t mask;
- sigemptyset (&mask);
- sigaddset (&mask, SIGINT);
- pthread_sigmask (SIG_UNBLOCK, &mask, NULL);
-
pthread_mutex_lock (&daemon_mutex);
if (non_daemon_count)
pthread_cond_wait (&daemon_cond, &daemon_mutex);
pthread_mutex_unlock (&daemon_mutex);
}
-void
-_Jv_ThreadInterrupt (_Jv_Thread_t *data)
+#if defined(SLOW_PTHREAD_SELF)
+
+// Support for pthread_self() lookup cache.
+
+volatile self_cache_entry _Jv_self_cache[SELF_CACHE_SIZE];
+
+
+_Jv_ThreadId_t
+_Jv_ThreadSelf_out_of_line(volatile self_cache_entry *sce, size_t high_sp_bits)
{
- data->flags |= FLAG_INTERRUPTED;
- pthread_kill (data->thread, INTR);
+ pthread_t self = pthread_self();
+ // The ordering between the following writes matters.
+ // On Alpha, we probably need a memory barrier in the middle.
+ sce -> high_sp_bits = high_sp_bits;
+ sce -> self = self;
+ return self;
}
+
+#endif /* SLOW_PTHREAD_SELF */
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