1 files changed, 98 insertions, 0 deletions
diff --git a/sysdeps/htl/sem-timedwait.c b/sysdeps/htl/sem-timedwait.c
new file mode 100644
index 0000000000..803a5c04f4
--- /dev/null
+++ b/sysdeps/htl/sem-timedwait.c
@@ -0,0 +1,98 @@
+/* Wait on a semaphore with a timeout.  Generic version.
+   Copyright (C) 2005-2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library;  if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <semaphore.h>
+#include <errno.h>
+#include <assert.h>
+
+#include <pt-internal.h>
+
+int
+__sem_timedwait_internal (sem_t *restrict sem,
+			  const struct timespec *restrict timeout)
+{
+  error_t err;
+  int drain;
+  struct __pthread *self;
+
+  __pthread_spin_lock (&sem->__lock);
+  if (sem->__value > 0)
+    /* Successful down.  */
+    {
+      sem->__value--;
+      __pthread_spin_unlock (&sem->__lock);
+      return 0;
+    }
+
+  if (timeout != NULL && (timeout->tv_nsec < 0 || timeout->tv_nsec >= 1000000000))
+    {
+      errno = EINVAL;
+      return -1;
+    }
+
+  /* Add ourselves to the queue.  */
+  self = _pthread_self ();
+
+  __pthread_enqueue (&sem->__queue, self);
+  __pthread_spin_unlock (&sem->__lock);
+
+  /* Block the thread.  */
+  if (timeout != NULL)
+    err = __pthread_timedblock (self, timeout, CLOCK_REALTIME);
+  else
+    {
+      err = 0;
+      __pthread_block (self);
+    }
+
+  __pthread_spin_lock (&sem->__lock);
+  if (self->prevp == NULL)
+    /* Another thread removed us from the queue, which means a wakeup message
+       has been sent.  It was either consumed while we were blocking, or
+       queued after we timed out and before we acquired the semaphore lock, in
+       which case the message queue must be drained.  */
+    drain = err ? 1 : 0;
+  else
+    {
+      /* We're still in the queue.  Noone attempted to wake us up, i.e. we
+         timed out.  */
+      __pthread_dequeue (self);
+      drain = 0;
+    }
+  __pthread_spin_unlock (&sem->__lock);
+
+  if (drain)
+    __pthread_block (self);
+
+  if (err)
+    {
+      assert (err == ETIMEDOUT);
+      errno = err;
+      return -1;
+    }
+
+  return 0;
+}
+
+int
+__sem_timedwait (sem_t *restrict sem, const struct timespec *restrict timeout)
+{
+  return __sem_timedwait_internal (sem, timeout);
+}
+
+weak_alias (__sem_timedwait, sem_timedwait);