1 files changed, 61 insertions, 0 deletions
diff --git a/sysdeps/htl/sem-post.c b/sysdeps/htl/sem-post.c
new file mode 100644
index 0000000000..12cb36c85a
--- /dev/null
+++ b/sysdeps/htl/sem-post.c
@@ -0,0 +1,61 @@
+/* Post a semaphore.  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 Library General Public License as
+   published by the Free Software Foundation; either version 2 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+#include <semaphore.h>
+#include <assert.h>
+
+#include <pt-internal.h>
+
+int
+__sem_post (sem_t *sem)
+{
+  struct __pthread *wakeup;
+
+  __pthread_spin_lock (&sem->__lock);
+  if (sem->__value > 0)
+    /* Do a quick up.  */
+    {
+      assert (sem->__queue == NULL);
+      sem->__value++;
+      __pthread_spin_unlock (&sem->__lock);
+      return 0;
+    }
+
+  if (sem->__queue == NULL)
+    /* No one waiting.  */
+    {
+      sem->__value = 1;
+      __pthread_spin_unlock (&sem->__lock);
+      return 0;
+    }
+
+  /* Wake someone up.  */
+
+  /* First dequeue someone.  */
+  wakeup = sem->__queue;
+  __pthread_dequeue (wakeup);
+
+  /* Then drop the lock and transfer control.  */
+  __pthread_spin_unlock (&sem->__lock);
+
+  __pthread_wakeup (wakeup);
+
+  return 0;
+}
+
+strong_alias (__sem_post, sem_post);