runtime: define nonblockingPipe

This requires defining pipe, pipe2, and setNonblock for various platforms.

The new function is currently only used on AIX. It will be used by
later CLs in this series.

Updates #27707

Change-Id: Id2f987b66b4c66a3ef40c22484ff1d14f58e9b31
Reviewed-on: https://go-review.googlesource.com/c/go/+/171822
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/src/runtime/nbpipe_pipe2.go b/src/runtime/nbpipe_pipe2.go
new file mode 100644
index 0000000000..f4c862cbff
--- /dev/null
+++ b/src/runtime/nbpipe_pipe2.go
@@ -0,0 +1,25 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build freebsd linux netbsd openbsd
+
+package runtime
+
+func pipe() (r, w int32, errno int32)
+func pipe2(flags int32) (r, w int32, errno int32)
+
+func nonblockingPipe() (r, w int32, errno int32) {
+	r, w, errno = pipe2(_O_NONBLOCK | _O_CLOEXEC)
+	if errno == -_ENOSYS {
+		r, w, errno = pipe()
+		if errno != 0 {
+			return -1, -1, errno
+		}
+		closeonexec(r)
+		setNonblock(r)
+		closeonexec(w)
+		setNonblock(w)
+	}
+	return r, w, errno
+}