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-rw-r--r--lib/libthr/thread/thr_sem.c271
1 files changed, 271 insertions, 0 deletions
diff --git a/lib/libthr/thread/thr_sem.c b/lib/libthr/thread/thr_sem.c
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index 0000000..6dbf7f4
--- /dev/null
+++ b/lib/libthr/thread/thr_sem.c
@@ -0,0 +1,271 @@
+/*
+ * Copyright (C) 2005 David Xu <davidxu@freebsd.org>.
+ * Copyright (C) 2000 Jason Evans <jasone@freebsd.org>.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice(s), this list of conditions and the following disclaimer as
+ * the first lines of this file unmodified other than the possible
+ * addition of one or more copyright notices.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice(s), this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include "namespace.h"
+#include <sys/types.h>
+#include <sys/queue.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <semaphore.h>
+#include <stdlib.h>
+#include <time.h>
+#include <_semaphore.h>
+#include "un-namespace.h"
+
+#include "thr_private.h"
+
+
+__weak_reference(_sem_init, sem_init);
+__weak_reference(_sem_destroy, sem_destroy);
+__weak_reference(_sem_getvalue, sem_getvalue);
+__weak_reference(_sem_trywait, sem_trywait);
+__weak_reference(_sem_wait, sem_wait);
+__weak_reference(_sem_timedwait, sem_timedwait);
+__weak_reference(_sem_post, sem_post);
+
+
+static inline int
+sem_check_validity(sem_t *sem)
+{
+
+ if ((sem != NULL) && ((*sem)->magic == SEM_MAGIC))
+ return (0);
+ else {
+ errno = EINVAL;
+ return (-1);
+ }
+}
+
+static sem_t
+sem_alloc(unsigned int value, semid_t semid, int system_sem)
+{
+ sem_t sem;
+
+ if (value > SEM_VALUE_MAX) {
+ errno = EINVAL;
+ return (NULL);
+ }
+
+ sem = (sem_t)malloc(sizeof(struct sem));
+ if (sem == NULL) {
+ errno = ENOSPC;
+ return (NULL);
+ }
+ bzero(sem, sizeof(*sem));
+ /*
+ * Fortunatly count and nwaiters are adjacency, so we can
+ * use umtx_wait to wait on it, umtx_wait needs an address
+ * can be accessed as a long interger.
+ */
+ sem->count = (u_int32_t)value;
+ sem->nwaiters = 0;
+ sem->magic = SEM_MAGIC;
+ sem->semid = semid;
+ sem->syssem = system_sem;
+ return (sem);
+}
+
+int
+_sem_init(sem_t *sem, int pshared, unsigned int value)
+{
+ semid_t semid;
+
+ semid = (semid_t)SEM_USER;
+ if ((pshared != 0) && (ksem_init(&semid, value) != 0))
+ return (-1);
+
+ (*sem) = sem_alloc(value, semid, pshared);
+ if ((*sem) == NULL) {
+ if (pshared != 0)
+ ksem_destroy(semid);
+ return (-1);
+ }
+ return (0);
+}
+
+int
+_sem_destroy(sem_t *sem)
+{
+ int retval;
+
+ if (sem_check_validity(sem) != 0)
+ return (-1);
+
+ /*
+ * If this is a system semaphore let the kernel track it otherwise
+ * make sure there are no waiters.
+ */
+ if ((*sem)->syssem != 0)
+ retval = ksem_destroy((*sem)->semid);
+ else {
+ retval = 0;
+ (*sem)->magic = 0;
+ }
+ if (retval == 0)
+ free(*sem);
+ return (retval);
+}
+
+int
+_sem_getvalue(sem_t * __restrict sem, int * __restrict sval)
+{
+ int retval;
+
+ if (sem_check_validity(sem) != 0)
+ return (-1);
+
+ if ((*sem)->syssem != 0)
+ retval = ksem_getvalue((*sem)->semid, sval);
+ else {
+ *sval = (int)(*sem)->count;
+ retval = 0;
+ }
+ return (retval);
+}
+
+int
+_sem_trywait(sem_t *sem)
+{
+ int val;
+
+ if (sem_check_validity(sem) != 0)
+ return (-1);
+
+ if ((*sem)->syssem != 0)
+ return (ksem_trywait((*sem)->semid));
+
+ while ((val = (*sem)->count) > 0) {
+ if (atomic_cmpset_acq_int(&(*sem)->count, val, val - 1))
+ return (0);
+ }
+ errno = EAGAIN;
+ return (-1);
+}
+
+int
+_sem_wait(sem_t *sem)
+{
+ struct pthread *curthread;
+ int val, retval;
+
+ if (sem_check_validity(sem) != 0)
+ return (-1);
+
+ curthread = _get_curthread();
+ if ((*sem)->syssem != 0) {
+ _thr_cancel_enter(curthread);
+ retval = ksem_wait((*sem)->semid);
+ _thr_cancel_leave(curthread);
+ return (retval);
+ }
+
+ _pthread_testcancel();
+ do {
+ while ((val = (*sem)->count) > 0) {
+ if (atomic_cmpset_acq_int(&(*sem)->count, val, val - 1))
+ return (0);
+ }
+ _thr_cancel_enter(curthread);
+ retval = _thr_umtx_wait((umtx_t *)&(*sem)->count, 0, NULL);
+ _thr_cancel_leave(curthread);
+ } while (retval == 0);
+ errno = retval;
+ return (-1);
+}
+
+int
+_sem_timedwait(sem_t * __restrict sem,
+ const struct timespec * __restrict abstime)
+{
+ struct timespec ts, ts2;
+ struct pthread *curthread;
+ int val, retval;
+
+ if (sem_check_validity(sem) != 0)
+ return (-1);
+
+ curthread = _get_curthread();
+ if ((*sem)->syssem != 0) {
+ _thr_cancel_enter(curthread);
+ retval = ksem_timedwait((*sem)->semid, abstime);
+ _thr_cancel_leave(curthread);
+ return (retval);
+ }
+
+ /*
+ * The timeout argument is only supposed to
+ * be checked if the thread would have blocked.
+ */
+ _pthread_testcancel();
+ do {
+ while ((val = (*sem)->count) > 0) {
+ if (atomic_cmpset_acq_int(&(*sem)->count, val, val - 1))
+ return (0);
+ }
+ if (abstime == NULL) {
+ errno = EINVAL;
+ return (-1);
+ }
+ clock_gettime(CLOCK_REALTIME, &ts);
+ TIMESPEC_SUB(&ts2, abstime, &ts);
+ _thr_cancel_enter(curthread);
+ retval = _thr_umtx_wait((umtx_t *)&(*sem)->count, 0, &ts2);
+ _thr_cancel_leave(curthread);
+ } while (retval == 0);
+ errno = retval;
+ return (-1);
+}
+
+int
+_sem_post(sem_t *sem)
+{
+ int val, retval;
+
+ if (sem_check_validity(sem) != 0)
+ return (-1);
+
+ if ((*sem)->syssem != 0)
+ return (ksem_post((*sem)->semid));
+
+ /*
+ * sem_post() is required to be safe to call from within
+ * signal handlers, these code should work as that.
+ */
+ do {
+ val = (*sem)->count;
+ } while (!atomic_cmpset_acq_int(&(*sem)->count, val, val + 1));
+ retval = _thr_umtx_wake((umtx_t *)&(*sem)->count, val + 1);
+ if (retval > 0)
+ retval = 0;
+ return (retval);
+}
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