142 lines
2.9 KiB
C
142 lines
2.9 KiB
C
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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#include "config.h"
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#include "runtime.h"
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#include <errno.h>
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#include <stdlib.h>
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#include <time.h>
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#include <semaphore.h>
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/* If we don't have sem_timedwait, use pthread_cond_timedwait instead.
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We don't always use condition variables because on some systems
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pthread_mutex_lock and pthread_mutex_unlock must be called by the
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same thread. That is never true of semaphores. */
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struct go_sem
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{
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sem_t sem;
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#ifndef HAVE_SEM_TIMEDWAIT
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int timedwait;
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pthread_mutex_t mutex;
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pthread_cond_t cond;
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#endif
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};
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/* Create a semaphore. */
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uintptr
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runtime_semacreate(void)
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{
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struct go_sem *p;
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/* Call malloc rather than runtime_malloc. This will allocate space
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on the C heap. We can't call runtime_malloc here because it
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could cause a deadlock. */
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p = malloc (sizeof (struct go_sem));
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if (sem_init (&p->sem, 0, 0) != 0)
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runtime_throw ("sem_init");
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#ifndef HAVE_SEM_TIMEDWAIT
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if (pthread_mutex_init (&p->mutex, NULL) != 0)
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runtime_throw ("pthread_mutex_init");
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if (pthread_cond_init (&p->cond, NULL) != 0)
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runtime_throw ("pthread_cond_init");
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#endif
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return (uintptr) p;
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}
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/* Acquire m->waitsema. */
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int32
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runtime_semasleep (int64 ns)
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{
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M *m;
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struct go_sem *sem;
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int r;
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m = runtime_m ();
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sem = (struct go_sem *) m->waitsema;
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if (ns >= 0)
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{
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int64 abs;
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struct timespec ts;
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int err;
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abs = ns + runtime_nanotime ();
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ts.tv_sec = abs / 1000000000LL;
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ts.tv_nsec = abs % 1000000000LL;
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err = 0;
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#ifdef HAVE_SEM_TIMEDWAIT
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r = sem_timedwait (&sem->sem, &ts);
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if (r != 0)
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err = errno;
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#else
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if (pthread_mutex_lock (&sem->mutex) != 0)
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runtime_throw ("pthread_mutex_lock");
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while ((r = sem_trywait (&sem->sem)) != 0)
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{
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r = pthread_cond_timedwait (&sem->cond, &sem->mutex, &ts);
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if (r != 0)
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{
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err = r;
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break;
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}
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}
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if (pthread_mutex_unlock (&sem->mutex) != 0)
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runtime_throw ("pthread_mutex_unlock");
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#endif
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if (err != 0)
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{
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if (err == ETIMEDOUT || err == EAGAIN || err == EINTR)
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return -1;
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runtime_throw ("sema_timedwait");
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}
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return 0;
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}
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while (sem_wait (&sem->sem) != 0)
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{
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if (errno == EINTR)
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continue;
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runtime_throw ("sem_wait");
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}
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return 0;
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}
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/* Wake up mp->waitsema. */
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void
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runtime_semawakeup (M *mp)
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{
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struct go_sem *sem;
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sem = (struct go_sem *) mp->waitsema;
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if (sem_post (&sem->sem) != 0)
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runtime_throw ("sem_post");
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#ifndef HAVE_SEM_TIMEDWAIT
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if (pthread_mutex_lock (&sem->mutex) != 0)
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runtime_throw ("pthread_mutex_lock");
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if (pthread_cond_broadcast (&sem->cond) != 0)
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runtime_throw ("pthread_cond_broadcast");
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if (pthread_mutex_unlock (&sem->mutex) != 0)
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runtime_throw ("pthread_mutex_unlock");
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#endif
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}
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void
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runtime_osinit(void)
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{
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}
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