nptl: Make pthread_attr_t dynamically extensible

This introduces the function __pthread_attr_extension to allocate the
extension space, which is freed by pthread_attr_destroy.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/nptl/pthread_attr_extension.c b/nptl/pthread_attr_extension.c
new file mode 100644
index 0000000000..3b128080cb
--- /dev/null
+++ b/nptl/pthread_attr_extension.c
@@ -0,0 +1,32 @@
+/* Allocate the extension space for struct pthread_attr.
+   Copyright (C) 2020 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <pthreadP.h>
+#include <stdlib.h>
+
+int
+ __pthread_attr_extension (struct pthread_attr *attr)
+{
+  if (attr->extension != NULL)
+    return 0;
+  attr->extension = calloc (sizeof (*attr->extension), 1);
+  if (attr->extension == NULL)
+    return errno;
+  return 0;
+}