1 files changed, 106 insertions, 0 deletions
diff --git a/REORG.TODO/nptl/sem_wait.c b/REORG.TODO/nptl/sem_wait.c
new file mode 100644
index 0000000000..625bf08c83
--- /dev/null
+++ b/REORG.TODO/nptl/sem_wait.c
@@ -0,0 +1,106 @@
+/* sem_wait -- wait on a semaphore.  Generic futex-using version.
+   Copyright (C) 2003-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Paul Mackerras <paulus@au.ibm.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 <lowlevellock.h>	/* lll_futex* used by the old code.  */
+#include "sem_waitcommon.c"
+
+int
+__new_sem_wait (sem_t *sem)
+{
+  /* We need to check whether we need to act upon a cancellation request here
+     because POSIX specifies that cancellation points "shall occur" in
+     sem_wait and sem_timedwait, which also means that they need to check
+     this regardless whether they block or not (unlike "may occur"
+     functions).  See the POSIX Rationale for this requirement: Section
+     "Thread Cancellation Overview" [1] and austin group issue #1076 [2]
+     for thoughs on why this may be a suboptimal design.
+
+     [1] http://pubs.opengroup.org/onlinepubs/9699919799/xrat/V4_xsh_chap02.html
+     [2] http://austingroupbugs.net/view.php?id=1076 for thoughts on why this
+   */
+  __pthread_testcancel ();
+
+  if (__new_sem_wait_fast ((struct new_sem *) sem, 0) == 0)
+    return 0;
+  else
+    return __new_sem_wait_slow((struct new_sem *) sem, NULL);
+}
+versioned_symbol (libpthread, __new_sem_wait, sem_wait, GLIBC_2_1);
+
+#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_1)
+int
+attribute_compat_text_section
+__old_sem_wait (sem_t *sem)
+{
+  int *futex = (int *) sem;
+  int err;
+
+  do
+    {
+      if (atomic_decrement_if_positive (futex) > 0)
+	return 0;
+
+      /* Enable asynchronous cancellation.  Required by the standard.  */
+      int oldtype = __pthread_enable_asynccancel ();
+
+      /* Always assume the semaphore is shared.  */
+      err = lll_futex_wait (futex, 0, LLL_SHARED);
+
+      /* Disable asynchronous cancellation.  */
+      __pthread_disable_asynccancel (oldtype);
+    }
+  while (err == 0 || err == -EWOULDBLOCK);
+
+  __set_errno (-err);
+  return -1;
+}
+
+compat_symbol (libpthread, __old_sem_wait, sem_wait, GLIBC_2_0);
+#endif
+
+int
+__new_sem_trywait (sem_t *sem)
+{
+  /* We must not fail spuriously, so require a definitive result even if this
+     may lead to a long execution time.  */
+  if (__new_sem_wait_fast ((struct new_sem *) sem, 1) == 0)
+    return 0;
+  __set_errno (EAGAIN);
+  return -1;
+}
+versioned_symbol (libpthread, __new_sem_trywait, sem_trywait, GLIBC_2_1);
+#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_1)
+int
+__old_sem_trywait (sem_t *sem)
+{
+  int *futex = (int *) sem;
+  int val;
+
+  if (*futex > 0)
+    {
+      val = atomic_decrement_if_positive (futex);
+      if (val > 0)
+	return 0;
+    }
+
+  __set_errno (EAGAIN);
+  return -1;
+}
+compat_symbol (libpthread, __old_sem_trywait, sem_trywait, GLIBC_2_0);
+#endif