1 files changed, 19 insertions, 0 deletions

diff --git a/nacl/curvecp/open_lock.c b/nacl/curvecp/open_lock.c
new file mode 100644
index 00000000..898f3b60
--- /dev/null
+++ b/nacl/curvecp/open_lock.c
@@ -0,0 +1,19 @@
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include "open.h"
+
+int open_lock(const char *fn)
+{
+#ifdef O_CLOEXEC
+  int fd = open(fn,O_RDWR | O_CLOEXEC);
+  if (fd == -1) return -1;
+#else
+  int fd = open(fn,O_RDWR);
+  if (fd == -1) return -1;
+  fcntl(fd,F_SETFD,1);
+#endif
+  if (lockf(fd,F_LOCK,0) == -1) { close(fd); return -1; }
+  return fd;
+}