406 lines
9.2 KiB
C++
406 lines
9.2 KiB
C++
// posix-threads.cc - interface between libjava and POSIX threads.
|
||
|
||
/* Copyright (C) 1998, 1999 Red Hat, Inc.
|
||
|
||
This file is part of libgcj.
|
||
|
||
This software is copyrighted work licensed under the terms of the
|
||
Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
|
||
details. */
|
||
|
||
// TO DO:
|
||
// * Document signal handling limitations
|
||
|
||
#include <config.h>
|
||
|
||
// 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;
|
||
};
|
||
|
||
// This is the key used to map from the POSIX thread value back to the
|
||
// Java object representing the thread. The key is global to all
|
||
// threads, so it is ok to make it a global here.
|
||
pthread_key_t _Jv_ThreadKey;
|
||
|
||
// This is the key used to map from the POSIX thread value back to the
|
||
// _Jv_Thread_t* representing the thread.
|
||
pthread_key_t _Jv_ThreadDataKey;
|
||
|
||
// We keep a count of all non-daemon threads which are running. When
|
||
// this reaches zero, _Jv_ThreadWait returns.
|
||
static pthread_mutex_t daemon_mutex;
|
||
static pthread_cond_t daemon_cond;
|
||
static int non_daemon_count;
|
||
|
||
// The signal to use when interrupting a thread.
|
||
#ifdef LINUX_THREADS
|
||
// LinuxThreads (prior to glibc 2.1) usurps both SIGUSR1 and SIGUSR2.
|
||
# define INTR SIGHUP
|
||
#else /* LINUX_THREADS */
|
||
# define INTR SIGUSR2
|
||
#endif /* LINUX_THREADS */
|
||
|
||
//
|
||
// These are the flags that can appear in _Jv_Thread_t.
|
||
//
|
||
|
||
// Thread started.
|
||
#define FLAG_START 0x01
|
||
// Thread is daemon.
|
||
#define FLAG_DAEMON 0x02
|
||
|
||
|
||
|
||
int
|
||
_Jv_CondWait (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu,
|
||
jlong millis, jint nanos)
|
||
{
|
||
if (_Jv_PthreadCheckMonitor (mu))
|
||
return 1;
|
||
|
||
int r;
|
||
pthread_mutex_t *pmu = _Jv_PthreadGetMutex (mu);
|
||
struct timespec ts;
|
||
jlong m, m2, startTime;
|
||
bool done_sleeping = false;
|
||
|
||
if (millis == 0 && nanos == 0)
|
||
{
|
||
#ifdef LINUX_THREADS
|
||
// pthread_cond_timedwait can be interrupted by a signal on linux, while
|
||
// pthread_cond_wait can not. So pthread_cond_timedwait() forever.
|
||
m = java::lang::Long::MAX_VALUE;
|
||
ts.tv_sec = LONG_MAX;
|
||
ts.tv_nsec = 0;
|
||
#endif
|
||
}
|
||
else
|
||
{
|
||
startTime = java::lang::System::currentTimeMillis();
|
||
m = millis + startTime;
|
||
ts.tv_sec = m / 1000;
|
||
ts.tv_nsec = ((m % 1000) * 1000000) + nanos;
|
||
}
|
||
|
||
java::lang::Thread *current = _Jv_ThreadCurrent();
|
||
|
||
do
|
||
{
|
||
r = EINTR;
|
||
// Check to ensure the thread hasn't already been interrupted.
|
||
if (!(current->isInterrupted ()))
|
||
{
|
||
#ifdef LINUX_THREADS
|
||
// FIXME: in theory, interrupt() could be called on this thread
|
||
// between the test above and the wait below, resulting in the
|
||
// interupt() call failing. I don't see a way to fix this
|
||
// without significant changes to the implementation.
|
||
r = pthread_cond_timedwait (cv, pmu, &ts);
|
||
#else
|
||
if (millis == 0 && nanos == 0)
|
||
r = pthread_cond_wait (cv, pmu);
|
||
else
|
||
r = pthread_cond_timedwait (cv, pmu, &ts);
|
||
#endif
|
||
}
|
||
|
||
if (r == EINTR)
|
||
{
|
||
/* 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. */
|
||
if (current->isInterrupted ())
|
||
{
|
||
r = 0;
|
||
done_sleeping = true;
|
||
}
|
||
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;
|
||
}
|
||
else
|
||
done_sleeping = true;
|
||
}
|
||
while (! done_sleeping);
|
||
|
||
return r != 0;
|
||
}
|
||
|
||
#ifndef RECURSIVE_MUTEX_IS_DEFAULT
|
||
|
||
void
|
||
_Jv_MutexInit (_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 */
|
||
|
||
// 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;
|
||
|
||
#endif /* HAVE_RECURSIVE_MUTEX */
|
||
}
|
||
|
||
#endif /* not RECURSIVE_MUTEX_IS_DEFAULT */
|
||
|
||
#if ! defined (LINUX_THREADS) && ! defined (HAVE_RECURSIVE_MUTEX)
|
||
|
||
void
|
||
_Jv_MutexDestroy (_Jv_Mutex_t *mu)
|
||
{
|
||
pthread_mutex_destroy (&mu->mutex);
|
||
pthread_mutex_destroy (&mu->mutex2);
|
||
pthread_cond_destroy (&mu->cond);
|
||
}
|
||
|
||
int
|
||
_Jv_MutexLock (_Jv_Mutex_t *mu)
|
||
{
|
||
if (pthread_mutex_lock (&mu->mutex))
|
||
return -1;
|
||
while (1)
|
||
{
|
||
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_unlock (&mu->mutex);
|
||
return 0;
|
||
}
|
||
|
||
int
|
||
_Jv_MutexUnlock (_Jv_Mutex_t *mu)
|
||
{
|
||
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;
|
||
}
|
||
|
||
#endif /* not LINUX_THREADS and not HAVE_RECURSIVE_MUTEX */
|
||
|
||
static void
|
||
handle_intr (int)
|
||
{
|
||
// Do nothing.
|
||
}
|
||
|
||
void
|
||
_Jv_InitThreads (void)
|
||
{
|
||
pthread_key_create (&_Jv_ThreadKey, NULL);
|
||
pthread_key_create (&_Jv_ThreadDataKey, NULL);
|
||
pthread_mutex_init (&daemon_mutex, NULL);
|
||
pthread_cond_init (&daemon_cond, 0);
|
||
non_daemon_count = 0;
|
||
|
||
// Arrange for the interrupt signal to interrupt system calls.
|
||
struct sigaction act;
|
||
act.sa_handler = handle_intr;
|
||
sigemptyset (&act.sa_mask);
|
||
act.sa_flags = 0;
|
||
sigaction (INTR, &act, NULL);
|
||
}
|
||
|
||
void
|
||
_Jv_ThreadInitData (_Jv_Thread_t **data, java::lang::Thread *)
|
||
{
|
||
_Jv_Thread_t *info = new _Jv_Thread_t;
|
||
info->flags = 0;
|
||
|
||
// FIXME register a finalizer for INFO here.
|
||
// FIXME also must mark INFO somehow.
|
||
|
||
*data = info;
|
||
}
|
||
|
||
void
|
||
_Jv_ThreadSetPriority (_Jv_Thread_t *data, jint prio)
|
||
{
|
||
if (data->flags & FLAG_START)
|
||
{
|
||
struct sched_param param;
|
||
|
||
param.sched_priority = prio;
|
||
pthread_setschedparam (data->thread, SCHED_RR, ¶m);
|
||
}
|
||
}
|
||
|
||
// 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.
|
||
static void *
|
||
really_start (void *x)
|
||
{
|
||
struct starter *info = (struct starter *) x;
|
||
|
||
pthread_setspecific (_Jv_ThreadKey, info->object);
|
||
pthread_setspecific (_Jv_ThreadDataKey, info->data);
|
||
info->method (info->object);
|
||
|
||
if (! (info->data->flags & FLAG_DAEMON))
|
||
{
|
||
pthread_mutex_lock (&daemon_mutex);
|
||
--non_daemon_count;
|
||
if (! non_daemon_count)
|
||
pthread_cond_signal (&daemon_cond);
|
||
pthread_mutex_unlock (&daemon_mutex);
|
||
}
|
||
|
||
return NULL;
|
||
}
|
||
|
||
void
|
||
_Jv_ThreadStart (java::lang::Thread *thread, _Jv_Thread_t *data,
|
||
_Jv_ThreadStartFunc *meth)
|
||
{
|
||
struct sched_param param;
|
||
pthread_attr_t attr;
|
||
struct starter *info;
|
||
|
||
if (data->flags & FLAG_START)
|
||
return;
|
||
data->flags |= FLAG_START;
|
||
|
||
param.sched_priority = thread->getPriority();
|
||
|
||
pthread_attr_init (&attr);
|
||
pthread_attr_setschedparam (&attr, ¶m);
|
||
|
||
// 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())
|
||
{
|
||
pthread_mutex_lock (&daemon_mutex);
|
||
++non_daemon_count;
|
||
pthread_mutex_unlock (&daemon_mutex);
|
||
}
|
||
else
|
||
data->flags |= FLAG_DAEMON;
|
||
int r = pthread_create (&data->thread, &attr, really_start, (void *) info);
|
||
|
||
pthread_attr_destroy (&attr);
|
||
|
||
if (r)
|
||
{
|
||
const char* msg = "Cannot create additional threads";
|
||
JvThrow (new java::lang::OutOfMemoryError (JvNewStringUTF (msg)));
|
||
}
|
||
}
|
||
|
||
void
|
||
_Jv_ThreadWait (void)
|
||
{
|
||
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)
|
||
{
|
||
pthread_kill (data->thread, INTR);
|
||
}
|