unix: add Pipe2 on illumos

Change-Id: Ib8d259c16b2ea4081f5ee8d927ef8658315268b8
Reviewed-on: https://go-review.googlesource.com/c/sys/+/254979
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matt Layher <mdlayher@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

unix/syscall_illumos.go

@@ -75,3 +75,16 @@ func Accept4(fd int, flags int) (nfd int, sa Sockaddr, err error) {
 	}
 	return
 }
+
+//sysnb	pipe2(p *[2]_C_int, flags int) (err error)
+
+func Pipe2(p []int, flags int) error {
+	if len(p) != 2 {
+		return EINVAL
+	}
+	var pp [2]_C_int
+	err := pipe2(&pp, flags)
+	p[0] = int(pp[0])
+	p[1] = int(pp[1])
+	return err
+}

unix/zsyscall_illumos_amd64.go

@@ -14,19 +14,22 @@ import (
 //go:cgo_import_dynamic libc_writev writev "libc.so"
 //go:cgo_import_dynamic libc_pwritev pwritev "libc.so"
 //go:cgo_import_dynamic libc_accept4 accept4 "libc.so"
+//go:cgo_import_dynamic libc_pipe2 pipe2 "libc.so"
 
 //go:linkname procreadv libc_readv
 //go:linkname procpreadv libc_preadv
 //go:linkname procwritev libc_writev
 //go:linkname procpwritev libc_pwritev
 //go:linkname procaccept4 libc_accept4
+//go:linkname procpipe2 libc_pipe2
 
 var (
 	procreadv,
 	procpreadv,
 	procwritev,
 	procpwritev,
-	procaccept4 syscallFunc
+	procaccept4,
+	procpipe2 syscallFunc
 )
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
@@ -99,3 +102,13 @@ func accept4(s int, rsa *RawSockaddrAny, addrlen *_Socklen, flags int) (fd int,
 	}
 	return
 }
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func pipe2(p *[2]_C_int, flags int) (err error) {
+	_, _, e1 := rawSysvicall6(uintptr(unsafe.Pointer(&procpipe2)), 2, uintptr(unsafe.Pointer(p)), uintptr(flags), 0, 0, 0, 0)
+	if e1 != 0 {
+		err = e1
+	}
+	return
+}