1 files changed, 80 insertions, 0 deletions
diff --git a/nptl/sem_post.c b/nptl/sem_post.c
new file mode 100644
index 0000000000..4906adf332
--- /dev/null
+++ b/nptl/sem_post.c
@@ -0,0 +1,80 @@
+/* sem_post -- post to a POSIX semaphore.  Generic futex-using version.
+   Copyright (C) 2003-2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Jakub Jelinek <jakub@redhat.com>, 2003.
+
+   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 <atomic.h>
+#include <errno.h>
+#include <sysdep.h>
+#include <lowlevellock.h>
+#include <internaltypes.h>
+#include <semaphore.h>
+
+#include <shlib-compat.h>
+
+int
+__new_sem_post (sem_t *sem)
+{
+  struct new_sem *isem = (struct new_sem *) sem;
+
+  __typeof (isem->value) cur;
+  do
+    {
+      cur = isem->value;
+      if (isem->value == SEM_VALUE_MAX)
+	{
+	  __set_errno (EOVERFLOW);
+	  return -1;
+	}
+    }
+  while (atomic_compare_and_exchange_bool_rel (&isem->value, cur + 1, cur));
+
+  atomic_full_barrier ();
+  if (isem->nwaiters > 0)
+    {
+      int err = lll_futex_wake (&isem->value, 1,
+				isem->private ^ FUTEX_PRIVATE_FLAG);
+      if (__builtin_expect (err, 0) < 0)
+	{
+	  __set_errno (-err);
+	  return -1;
+	}
+    }
+  return 0;
+}
+versioned_symbol (libpthread, __new_sem_post, sem_post, GLIBC_2_1);
+
+
+#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_1)
+int
+attribute_compat_text_section
+__old_sem_post (sem_t *sem)
+{
+  int *futex = (int *) sem;
+
+  (void) atomic_increment_val (futex);
+  /* We always have to assume it is a shared semaphore.  */
+  int err = lll_futex_wake (futex, 1, LLL_SHARED);
+  if (__builtin_expect (err, 0) < 0)
+    {
+      __set_errno (-err);
+      return -1;
+    }
+  return 0;
+}
+compat_symbol (libpthread, __old_sem_post, sem_post, GLIBC_2_0);
+#endif