Move atomic io function to a separate module

We'll be using it on various places of the SSSD. The function is in its
own file to allow using just the one piece without having to drag in the
whole util.c module.

1 files changed, 40 insertions, 0 deletions

diff --git a/src/util/atomic_io.h b/src/util/atomic_io.h
new file mode 100644
index 000000000..ffae31d6c
--- /dev/null
+++ b/src/util/atomic_io.h
@@ -0,0 +1,40 @@
+/*
+    Authors:
+        Jan Cholasta <jcholast@redhat.com>
+
+    Copyright (C) 2012 Red Hat
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    This program 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef __SSSD_ATOMIC_IO_H__
+#define __SSSD_ATOMIC_IO_H__
+
+#include <unistd.h>
+#include <stdbool.h>
+#include <poll.h>
+#include <errno.h>
+
+/* Performs a read or write operation in an manner that is seemingly atomic
+ * to the caller.
+ *
+ * Please note that the function does not perform any asynchronous operation
+ * so the operation might potentially block
+ */
+ssize_t sss_atomic_io_s(int fd, void *buf, size_t n, bool do_read);
+
+#define sss_atomic_read_s(fd, buf, n)  sss_atomic_io_s(fd, buf, n, true)
+#define sss_atomic_write_s(fd, buf, n) sss_atomic_io_s(fd, buf, n, false)
+
+#endif /* __SSSD_ATOMIC_IO_H__ */