gcc/libjava/posix-threads.cc

390 lines
8.7 KiB
C++
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

// posix-threads.cc - interface between libjava and POSIX threads.
/* Copyright (C) 1998, 1999 Cygnus Solutions
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 <gcj/cni.h>
#include <jvm.h>
#include <java/lang/Thread.h>
#include <java/lang/System.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 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
// Thread was interrupted by _Jv_ThreadInterrupt.
#define FLAG_INTERRUPTED 0x04
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)
r = pthread_cond_wait (cv, pmu);
else
{
startTime = java::lang::System::currentTimeMillis();
m = millis + startTime;
do
{
ts.tv_sec = m / 1000;
ts.tv_nsec = ((m % 1000) * 1000000) + nanos;
r = pthread_cond_timedwait (cv, pmu, &ts);
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. */
_Jv_Thread_t *current = _Jv_ThreadCurrentData();
if (current->flags & FLAG_INTERRUPTED)
{
current->flags &= ~(FLAG_INTERRUPTED);
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);
// 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 *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, &param);
}
}
// 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, &param);
// 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;
pthread_create (&data->thread, &attr, really_start, (void *) info);
pthread_attr_destroy (&attr);
}
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)
{
data->flags |= FLAG_INTERRUPTED;
pthread_kill (data->thread, INTR);
}