1 files changed, 66 insertions, 0 deletions
diff --git a/src/util/non_blocking.c b/src/util/non_blocking.c
new file mode 100644
index 0000000..6427cd8
--- /dev/null
+++ b/src/util/non_blocking.c
@@ -0,0 +1,66 @@
+/*++
+/* NAME
+/*	non_blocking 3
+/* SUMMARY
+/*	set/clear non-blocking flag
+/* SYNOPSIS
+/*	#include <iostuff.h>
+/*
+/*	int	non_blocking(int fd, int on)
+/* DESCRIPTION
+/*	the \fInon_blocking\fR() function manipulates the non-blocking
+/*	flag for the specified open file, and returns the old setting.
+/*
+/*	Arguments:
+/* .IP fd
+/*	A file descriptor.
+/* .IP on
+/*	For non-blocking I/O, specify a non-zero value (or use the
+/*	NON_BLOCKING constant); for blocking I/O, specify zero
+/*	(or use the BLOCKING constant).
+/*
+/*	The result is non-zero when the non-blocking flag was enabled.
+/* DIAGNOSTICS
+/*	All errors are fatal.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System interfaces. */
+
+#include "sys_defs.h"
+#include <fcntl.h>
+
+/* Utility library. */
+
+#include "msg.h"
+#include "iostuff.h"
+
+/* Backwards compatibility */
+#ifndef O_NONBLOCK
+#define PATTERN	FNDELAY
+#else
+#define PATTERN	O_NONBLOCK
+#endif
+
+/* non_blocking - set/clear non-blocking flag */
+
+int     non_blocking(fd, on)
+int     fd;
+int     on;
+{
+    int     flags;
+
+    if ((flags = fcntl(fd, F_GETFL, 0)) < 0)
+	msg_fatal("fcntl: get flags: %m");
+    if (fcntl(fd, F_SETFL, on ? flags | PATTERN : flags & ~PATTERN) < 0)
+	msg_fatal("fcntl: set non-blocking flag %s: %m", on ? "on" : "off");
+    return ((flags & PATTERN) != 0);
+}