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, 17 insertions, 0 deletions

diff --git a/src/runtime/os_aix.go b/src/runtime/os_aix.go
index 84d86e5ff1..855ae6ff46 100644
--- a/src/runtime/os_aix.go
+++ b/src/runtime/os_aix.go
@@ -357,3 +357,20 @@ func setupSystemConf() {
 		cpu.HWCap2 |= cpu.PPC_FEATURE2_ARCH_3_00
 	}
 }
+
+//go:nosplit
+func fcntl(fd, cmd int32, arg uintptr) int32 {
+	r, _ := syscall3(&libc_fcntl, uintptr(fd), uintptr(cmd), arg)
+	return int32(r)
+}
+
+//go:nosplit
+func closeonexec(fd int32) {
+	fcntl(fd, _F_SETFD, _FD_CLOEXEC)
+}
+
+//go:nosplit
+func setNonblock(fd int32) {
+	flags := fcntl(fd, _F_GETFL, 0)
+	fcntl(fd, _F_SETFL, uintptr(flags|_O_NONBLOCK))
+}