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406 lines
9.2 KiB
C++
406 lines
9.2 KiB
C++
// posix-threads.cc - interface between libjava and POSIX threads.
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/* Copyright (C) 1998, 1999 Red Hat, Inc.
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This file is part of libgcj.
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This software is copyrighted work licensed under the terms of the
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Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
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details. */
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// TO DO:
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// * Document signal handling limitations
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#include <config.h>
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// If we're using the Boehm GC, then we need to override some of the
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// thread primitives. This is fairly gross.
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#ifdef HAVE_BOEHM_GC
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extern "C"
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{
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#include <gcconfig.h>
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#include <gc.h>
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};
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#endif /* HAVE_BOEHM_GC */
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#include <stdlib.h>
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#include <time.h>
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#include <signal.h>
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#include <errno.h>
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#include <limits.h>
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#include <gcj/cni.h>
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#include <jvm.h>
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#include <java/lang/Thread.h>
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#include <java/lang/System.h>
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#include <java/lang/Long.h>
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#include <java/lang/OutOfMemoryError.h>
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// This is used to implement thread startup.
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struct starter
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{
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_Jv_ThreadStartFunc *method;
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java::lang::Thread *object;
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_Jv_Thread_t *data;
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};
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// This is the key used to map from the POSIX thread value back to the
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// Java object representing the thread. The key is global to all
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// threads, so it is ok to make it a global here.
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pthread_key_t _Jv_ThreadKey;
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// This is the key used to map from the POSIX thread value back to the
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// _Jv_Thread_t* representing the thread.
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pthread_key_t _Jv_ThreadDataKey;
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// We keep a count of all non-daemon threads which are running. When
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// this reaches zero, _Jv_ThreadWait returns.
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static pthread_mutex_t daemon_mutex;
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static pthread_cond_t daemon_cond;
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static int non_daemon_count;
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// The signal to use when interrupting a thread.
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#ifdef LINUX_THREADS
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// LinuxThreads (prior to glibc 2.1) usurps both SIGUSR1 and SIGUSR2.
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# define INTR SIGHUP
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#else /* LINUX_THREADS */
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# define INTR SIGUSR2
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#endif /* LINUX_THREADS */
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//
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// These are the flags that can appear in _Jv_Thread_t.
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//
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// Thread started.
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#define FLAG_START 0x01
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// Thread is daemon.
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#define FLAG_DAEMON 0x02
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int
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_Jv_CondWait (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu,
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jlong millis, jint nanos)
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{
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if (_Jv_PthreadCheckMonitor (mu))
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return 1;
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int r;
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pthread_mutex_t *pmu = _Jv_PthreadGetMutex (mu);
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struct timespec ts;
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jlong m, m2, startTime;
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bool done_sleeping = false;
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if (millis == 0 && nanos == 0)
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{
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#ifdef LINUX_THREADS
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// pthread_cond_timedwait can be interrupted by a signal on linux, while
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// pthread_cond_wait can not. So pthread_cond_timedwait() forever.
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m = java::lang::Long::MAX_VALUE;
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ts.tv_sec = LONG_MAX;
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ts.tv_nsec = 0;
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#endif
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}
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else
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{
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startTime = java::lang::System::currentTimeMillis();
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m = millis + startTime;
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ts.tv_sec = m / 1000;
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ts.tv_nsec = ((m % 1000) * 1000000) + nanos;
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}
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java::lang::Thread *current = _Jv_ThreadCurrent();
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do
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{
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r = EINTR;
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// Check to ensure the thread hasn't already been interrupted.
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if (!(current->isInterrupted ()))
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{
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#ifdef LINUX_THREADS
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// FIXME: in theory, interrupt() could be called on this thread
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// between the test above and the wait below, resulting in the
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// interupt() call failing. I don't see a way to fix this
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// without significant changes to the implementation.
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r = pthread_cond_timedwait (cv, pmu, &ts);
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#else
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if (millis == 0 && nanos == 0)
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r = pthread_cond_wait (cv, pmu);
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else
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r = pthread_cond_timedwait (cv, pmu, &ts);
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#endif
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}
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if (r == EINTR)
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{
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/* We were interrupted by a signal. Either this is
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because we were interrupted intentionally (i.e. by
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Thread.interrupt()) or by the GC if it is
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signal-based. */
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if (current->isInterrupted ())
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{
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r = 0;
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done_sleeping = true;
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}
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else
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{
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/* We were woken up by the GC or another signal. */
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m2 = java::lang::System::currentTimeMillis ();
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if (m2 >= m)
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{
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r = 0;
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done_sleeping = true;
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}
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}
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}
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else if (r == ETIMEDOUT)
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{
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/* A timeout is a normal result. */
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r = 0;
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done_sleeping = true;
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}
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else
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done_sleeping = true;
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}
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while (! done_sleeping);
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return r != 0;
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}
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#ifndef RECURSIVE_MUTEX_IS_DEFAULT
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void
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_Jv_MutexInit (_Jv_Mutex_t *mu)
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{
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#ifdef HAVE_RECURSIVE_MUTEX
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pthread_mutexattr_t *val = NULL;
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#if defined (HAVE_PTHREAD_MUTEXATTR_SETTYPE)
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pthread_mutexattr_t attr;
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// If this is slow, then allocate it statically and only initialize
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// it once.
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pthread_mutexattr_init (&attr);
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pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE);
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val = &attr;
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#elif defined (HAVE_PTHREAD_MUTEXATTR_SETKIND_NP)
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pthread_mutexattr_t attr;
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pthread_mutexattr_init (&attr);
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pthread_mutexattr_setkind_np (&attr, PTHREAD_MUTEX_RECURSIVE_NP);
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val = &attr;
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#endif
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pthread_mutex_init (_Jv_PthreadGetMutex (mu), val);
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#ifdef PTHREAD_MUTEX_IS_STRUCT
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mu->count = 0;
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#endif
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#if defined (HAVE_PTHREAD_MUTEXATTR_SETTYPE) || defined (HAVE_PTHREAD_MUTEXATTR_SETKIND_NP)
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pthread_mutexattr_destroy (&attr);
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#endif
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#else /* HAVE_RECURSIVE_MUTEX */
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// No recursive mutex, so simulate one.
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pthread_mutex_init (&mu->mutex, NULL);
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pthread_mutex_init (&mu->mutex2, NULL);
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pthread_cond_init (&mu->cond, 0);
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mu->count = 0;
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#endif /* HAVE_RECURSIVE_MUTEX */
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}
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#endif /* not RECURSIVE_MUTEX_IS_DEFAULT */
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#if ! defined (LINUX_THREADS) && ! defined (HAVE_RECURSIVE_MUTEX)
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void
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_Jv_MutexDestroy (_Jv_Mutex_t *mu)
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{
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pthread_mutex_destroy (&mu->mutex);
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pthread_mutex_destroy (&mu->mutex2);
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pthread_cond_destroy (&mu->cond);
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}
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int
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_Jv_MutexLock (_Jv_Mutex_t *mu)
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{
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if (pthread_mutex_lock (&mu->mutex))
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return -1;
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while (1)
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{
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if (mu->count == 0)
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{
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// Grab the lock.
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mu->thread = pthread_self ();
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mu->count = 1;
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pthread_mutex_lock (&mu->mutex2);
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break;
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}
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else if (pthread_self () == mu->thread)
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{
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// Already have the lock.
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mu->count += 1;
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break;
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}
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else
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{
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// Try to acquire the lock.
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pthread_cond_wait (&mu->cond, &mu->mutex);
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}
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}
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pthread_mutex_unlock (&mu->mutex);
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return 0;
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}
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int
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_Jv_MutexUnlock (_Jv_Mutex_t *mu)
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{
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if (pthread_mutex_lock (&mu->mutex))
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return -1;
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int r = 0;
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if (mu->count == 0 || pthread_self () != mu->thread)
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r = -1;
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else
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{
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mu->count -= 1;
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if (! mu->count)
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{
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pthread_mutex_unlock (&mu->mutex2);
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pthread_cond_signal (&mu->cond);
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}
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}
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pthread_mutex_unlock (&mu->mutex);
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return r;
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}
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#endif /* not LINUX_THREADS and not HAVE_RECURSIVE_MUTEX */
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static void
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handle_intr (int)
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{
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// Do nothing.
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}
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void
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_Jv_InitThreads (void)
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{
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pthread_key_create (&_Jv_ThreadKey, NULL);
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pthread_key_create (&_Jv_ThreadDataKey, NULL);
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pthread_mutex_init (&daemon_mutex, NULL);
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pthread_cond_init (&daemon_cond, 0);
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non_daemon_count = 0;
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// Arrange for the interrupt signal to interrupt system calls.
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struct sigaction act;
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act.sa_handler = handle_intr;
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sigemptyset (&act.sa_mask);
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act.sa_flags = 0;
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sigaction (INTR, &act, NULL);
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}
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void
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_Jv_ThreadInitData (_Jv_Thread_t **data, java::lang::Thread *)
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{
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_Jv_Thread_t *info = new _Jv_Thread_t;
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info->flags = 0;
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// FIXME register a finalizer for INFO here.
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// FIXME also must mark INFO somehow.
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*data = info;
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}
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void
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_Jv_ThreadSetPriority (_Jv_Thread_t *data, jint prio)
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{
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if (data->flags & FLAG_START)
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{
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struct sched_param param;
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param.sched_priority = prio;
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pthread_setschedparam (data->thread, SCHED_RR, ¶m);
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}
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}
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// This function is called when a thread is started. We don't arrange
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// to call the `run' method directly, because this function must
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// return a value.
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static void *
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really_start (void *x)
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{
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struct starter *info = (struct starter *) x;
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pthread_setspecific (_Jv_ThreadKey, info->object);
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pthread_setspecific (_Jv_ThreadDataKey, info->data);
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info->method (info->object);
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if (! (info->data->flags & FLAG_DAEMON))
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{
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pthread_mutex_lock (&daemon_mutex);
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--non_daemon_count;
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if (! non_daemon_count)
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pthread_cond_signal (&daemon_cond);
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pthread_mutex_unlock (&daemon_mutex);
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}
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return NULL;
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}
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void
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_Jv_ThreadStart (java::lang::Thread *thread, _Jv_Thread_t *data,
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_Jv_ThreadStartFunc *meth)
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{
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struct sched_param param;
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pthread_attr_t attr;
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struct starter *info;
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if (data->flags & FLAG_START)
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return;
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data->flags |= FLAG_START;
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param.sched_priority = thread->getPriority();
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pthread_attr_init (&attr);
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pthread_attr_setschedparam (&attr, ¶m);
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// FIXME: handle marking the info object for GC.
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info = (struct starter *) _Jv_AllocBytes (sizeof (struct starter));
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info->method = meth;
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info->object = thread;
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info->data = data;
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if (! thread->isDaemon())
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{
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pthread_mutex_lock (&daemon_mutex);
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++non_daemon_count;
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pthread_mutex_unlock (&daemon_mutex);
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}
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else
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data->flags |= FLAG_DAEMON;
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int r = pthread_create (&data->thread, &attr, really_start, (void *) info);
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pthread_attr_destroy (&attr);
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if (r)
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{
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const char* msg = "Cannot create additional threads";
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JvThrow (new java::lang::OutOfMemoryError (JvNewStringUTF (msg)));
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}
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}
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void
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_Jv_ThreadWait (void)
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{
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pthread_mutex_lock (&daemon_mutex);
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if (non_daemon_count)
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pthread_cond_wait (&daemon_cond, &daemon_mutex);
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pthread_mutex_unlock (&daemon_mutex);
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}
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void
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_Jv_ThreadInterrupt (_Jv_Thread_t *data)
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{
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pthread_kill (data->thread, INTR);
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}
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