os, internal/syscall/unix: use pipe2 instead of pipe on illumos

Illumos provides the pipe2 syscall. Add a wrapper to
internal/syscall/unix and use it to implement os.Pipe.

Change-Id: I26ecdbcae1e8d51f80e2bc8a86fb129826387b1f
Reviewed-on: https://go-review.googlesource.com/c/go/+/254981
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

1 files changed, 34 insertions, 0 deletions

diff --git a/src/internal/syscall/unix/pipe2_illumos.go b/src/internal/syscall/unix/pipe2_illumos.go
new file mode 100644
index 0000000000..f3ac8d29df
--- /dev/null
+++ b/src/internal/syscall/unix/pipe2_illumos.go
@@ -0,0 +1,34 @@
+// Copyright 2020 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 illumos
+
+package unix
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+//go:cgo_import_dynamic libc_pipe2 pipe2 "libc.so"
+
+//go:linkname procpipe2 libc_pipe2
+
+var procpipe2 uintptr
+
+type _C_int int32
+
+func Pipe2(p []int, flags int) error {
+	if len(p) != 2 {
+		return syscall.EINVAL
+	}
+	var pp [2]_C_int
+	_, _, errno := syscall6(uintptr(unsafe.Pointer(&procpipe2)), 2, uintptr(unsafe.Pointer(&pp)), uintptr(flags), 0, 0, 0, 0)
+	if errno != 0 {
+		return errno
+	}
+	p[0] = int(pp[0])
+	p[1] = int(pp[1])
+	return nil
+}