syscall, os: use pipe2 syscall on NetBSD instead of pipe

The pipe2 syscall is part of NetBSD since version 6.0 and thus exists in
all officially supported versions (6.0 through 6.1 and 7.0+).

Follows CL 38426

Change-Id: I7b62b507300c3dfbcc6ae56408a7d7088ddccc77
Reviewed-on: https://go-review.googlesource.com/94035
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Benny Siegert <bsiegert@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/os/pipe2_bsd.go

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build freebsd netbsd
+
 package os
 
 import "syscall"

src/os/pipe_bsd.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly nacl netbsd openbsd solaris
+// +build darwin dragonfly nacl openbsd solaris
 
 package os
 

src/syscall/forkpipe.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly netbsd openbsd solaris
+// +build darwin dragonfly openbsd solaris
 
 package syscall
 

src/syscall/forkpipe2.go

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build freebsd netbsd
+
 package syscall
 
 func forkExecPipe(p []int) error {

src/syscall/syscall_netbsd.go

@@ -102,13 +102,20 @@ func direntNamlen(buf []byte) (uint64, bool) {
 	return readInt(buf, unsafe.Offsetof(Dirent{}.Namlen), unsafe.Sizeof(Dirent{}.Namlen))
 }
 
-//sysnb pipe() (fd1 int, fd2 int, err error)
 func Pipe(p []int) (err error) {
+	return Pipe2(p, 0)
+}
+
+//sysnb pipe2(p *[2]_C_int, flags int) (err error)
+func Pipe2(p []int, flags int) error {
 	if len(p) != 2 {
 		return EINVAL
 	}
-	p[0], p[1], err = pipe()
-	return
+	var pp [2]_C_int
+	err := pipe2(&pp, flags)
+	p[0] = int(pp[0])
+	p[1] = int(pp[1])
+	return err
 }
 
 //sys getdents(fd int, buf []byte) (n int, err error)

src/syscall/zsyscall_netbsd_386.go

@@ -261,10 +261,8 @@ func fcntl(fd int, cmd int, arg int) (val int, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func pipe() (fd1 int, fd2 int, err error) {
-	r0, r1, e1 := RawSyscall(SYS_PIPE, 0, 0, 0)
-	fd1 = int(r0)
-	fd2 = int(r1)
+func pipe2(p *[2]_C_int, flags int) (err error) {
+	_, _, e1 := RawSyscall(SYS_PIPE2, uintptr(unsafe.Pointer(p)), uintptr(flags), 0)
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}

src/syscall/zsyscall_netbsd_amd64.go

@@ -261,10 +261,8 @@ func fcntl(fd int, cmd int, arg int) (val int, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func pipe() (fd1 int, fd2 int, err error) {
-	r0, r1, e1 := RawSyscall(SYS_PIPE, 0, 0, 0)
-	fd1 = int(r0)
-	fd2 = int(r1)
+func pipe2(p *[2]_C_int, flags int) (err error) {
+	_, _, e1 := RawSyscall(SYS_PIPE2, uintptr(unsafe.Pointer(p)), uintptr(flags), 0)
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}

src/syscall/zsyscall_netbsd_arm.go

@@ -261,10 +261,8 @@ func fcntl(fd int, cmd int, arg int) (val int, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func pipe() (fd1 int, fd2 int, err error) {
-	r0, r1, e1 := RawSyscall(SYS_PIPE, 0, 0, 0)
-	fd1 = int(r0)
-	fd2 = int(r1)
+func pipe2(p *[2]_C_int, flags int) (err error) {
+	_, _, e1 := RawSyscall(SYS_PIPE2, uintptr(unsafe.Pointer(p)), uintptr(flags), 0)
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}