unix: add Accept4 on illumos

Wrap the accept syscall which is available on illumos.

Also use tabs instead of spaces in the //sys comments in
syscall_illumos.go

Change-Id: Ic7fbfe29b44c6a168b9be4d4679a6321cc891bf1
Reviewed-on: https://go-review.googlesource.com/c/sys/+/254717
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matt Layher <mdlayher@gmail.com>
Trust: Tobias Klauser <tobias.klauser@gmail.com>

unix/syscall_illumos.go

@@ -55,3 +55,23 @@ func Pwritev(fd int, iovs [][]byte, off int64) (n int, err error) {
 	n, err = pwritev(fd, iovecs, off)
 	return n, err
 }
+
+//sys	accept4(s int, rsa *RawSockaddrAny, addrlen *_Socklen, flags int) (fd int, err error)
+
+func Accept4(fd int, flags int) (nfd int, sa Sockaddr, err error) {
+	var rsa RawSockaddrAny
+	var len _Socklen = SizeofSockaddrAny
+	nfd, err = accept4(fd, &rsa, &len, flags)
+	if err != nil {
+		return
+	}
+	if len > SizeofSockaddrAny {
+		panic("RawSockaddrAny too small")
+	}
+	sa, err = anyToSockaddr(fd, &rsa)
+	if err != nil {
+		Close(nfd)
+		nfd = 0
+	}
+	return
+}

unix/zsyscall_illumos_amd64.go

@@ -13,17 +13,20 @@ import (
 //go:cgo_import_dynamic libc_preadv preadv "libc.so"
 //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:linkname procreadv libc_readv
 //go:linkname procpreadv libc_preadv
 //go:linkname procwritev libc_writev
 //go:linkname procpwritev libc_pwritev
+//go:linkname procaccept4 libc_accept4
 
 var (
 	procreadv,
 	procpreadv,
 	procwritev,
-	procpwritev syscallFunc
+	procpwritev,
+	procaccept4 syscallFunc
 )
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
@@ -85,3 +88,14 @@ func pwritev(fd int, iovs []Iovec, off int64) (n int, err error) {
 	}
 	return
 }
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func accept4(s int, rsa *RawSockaddrAny, addrlen *_Socklen, flags int) (fd int, err error) {
+	r0, _, e1 := sysvicall6(uintptr(unsafe.Pointer(&procaccept4)), 4, uintptr(s), uintptr(unsafe.Pointer(rsa)), uintptr(unsafe.Pointer(addrlen)), uintptr(flags), 0, 0)
+	fd = int(r0)
+	if e1 != 0 {
+		err = e1
+	}
+	return
+}