Split out the semaphore functions.

ok guenther@

1 files changed, 202 insertions, 0 deletions

diff --git a/lib/librthread/rthread_sem.c b/lib/librthread/rthread_sem.c
new file mode 100644
index 00000000000..ea855d5d1d3
--- /dev/null
+++ b/lib/librthread/rthread_sem.c
@@ -0,0 +1,202 @@
+/*	$OpenBSD */
+/*
+ * Copyright (c) 2004,2005 Ted Unangst <tedu@openbsd.org>
+ * All Rights Reserved.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include <pthread.h>
+
+#include "rthread.h"
+
+/*
+ * Internal implementation of semaphores
+ */
+int
+_sem_wait(sem_t sem, int tryonly)
+{
+
+	_spinlock(&sem->lock);
+	return (_sem_waitl(sem, tryonly, 0, NULL));
+}
+
+int
+_sem_waitl(sem_t sem, int tryonly, clockid_t clock_id,
+    const struct timespec *abstime)
+{
+	int do_sleep;
+
+again:
+	if (sem->value == 0) {
+		if (tryonly) {
+			_spinunlock(&sem->lock);
+			return (0);
+		}
+		sem->waitcount++;
+		do_sleep = 1;
+	} else {
+		sem->value--;
+		do_sleep = 0;
+	}
+
+	if (do_sleep) {
+		if (thrsleep(sem, clock_id, abstime, &sem->lock) == -1 &&
+		    errno == EWOULDBLOCK)
+			return (0);
+		_spinlock(&sem->lock);
+		sem->waitcount--;
+		goto again;
+	}
+	_spinunlock(&sem->lock);
+	return (1);
+}
+
+/* always increment count */
+int
+_sem_post(sem_t sem)
+{
+	int rv = 0;
+
+	_spinlock(&sem->lock);
+	sem->value++;
+	if (sem->waitcount) {
+		thrwakeup(sem, 1);
+		rv = 1;
+	}
+	_spinunlock(&sem->lock);
+	return (rv);
+}
+
+/* only increment count if a waiter */
+int
+_sem_wakeup(sem_t sem)
+{
+	int rv = 0;
+
+	_spinlock(&sem->lock);
+	if (sem->waitcount) {
+		sem->value++;
+		thrwakeup(sem, 1);
+		rv = 1;
+	}
+	_spinunlock(&sem->lock);
+	return (rv);
+}
+
+
+int
+_sem_wakeall(sem_t sem)
+{
+	int rv;
+
+	_spinlock(&sem->lock);
+	rv = sem->waitcount;
+	sem->value += rv;
+	thrwakeup(sem, 0);
+	_spinunlock(&sem->lock);
+
+	return (rv);
+}
+
+/*
+ * exported semaphores
+ */
+int
+sem_init(sem_t *semp, int pshared, unsigned int value)
+{
+	sem_t sem;
+
+	if (pshared) {
+		errno = EPERM;
+		return (-1);
+	}
+
+	sem = calloc(1, sizeof(*sem));
+	if (!sem)
+		return (-1);
+	sem->value = value;
+	*semp = sem;
+
+	return (0);
+}
+
+int
+sem_destroy(sem_t *semp)
+{
+	if (!*semp)
+		return (EINVAL);
+	if ((*semp)->waitcount) {
+#define MSG "sem_destroy on semaphore with waiters!\n"
+		write(2, MSG, sizeof(MSG) - 1);
+#undef MSG
+		return (EBUSY);
+	}
+	free(*semp);
+	*semp = NULL;
+
+	return (0);
+}
+
+int
+sem_getvalue(sem_t *semp, int *sval)
+{
+	sem_t sem = *semp;
+
+	_spinlock(&sem->lock);
+	*sval = sem->value;
+	_spinunlock(&sem->lock);
+
+	return (0);
+}
+
+int
+sem_post(sem_t *semp)
+{
+	sem_t sem = *semp;
+
+	_sem_post(sem);
+
+	return (0);
+}
+
+int
+sem_wait(sem_t *semp)
+{
+	sem_t sem = *semp;
+
+	_sem_wait(sem, 0);
+
+	return (0);
+}
+
+int
+sem_trywait(sem_t *semp)
+{
+	sem_t sem = *semp;
+	int rv;
+
+	rv = _sem_wait(sem, 1);
+
+	if (!rv) {
+		errno = EAGAIN;
+		return (-1);
+	}
+
+	return (0);
+}
+