unix: unify Recvmsg epilogues

Follow CL 361258 which did the same in package syscall.

Change-Id: I721406286d84ec999978e7e1ea25b6a2b3e195e6
Reviewed-on: https://go-review.googlesource.com/c/sys/+/393294
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

unix/syscall_aix.go

@@ -215,10 +215,9 @@ func Accept(fd int) (nfd int, sa Sockaddr, err error) {
 	return
 }
 
-func Recvmsg(fd int, p, oob []byte, flags int) (n, oobn int, recvflags int, from Sockaddr, err error) {
+func recvmsgRaw(fd int, p, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn int, recvflags int, err error) {
 	// Recvmsg not implemented on AIX
-	sa := new(SockaddrUnix)
+	return -1, -1, -1, ENOSYS
-	return -1, -1, -1, sa, ENOSYS
 }
 
 func sendmsgN(fd int, p, oob []byte, ptr unsafe.Pointer, salen _Socklen, flags int) (n int, err error) {

unix/syscall_bsd.go

@@ -325,10 +325,9 @@ func GetsockoptString(fd, level, opt int) (string, error) {
 //sys	sendto(s int, buf []byte, flags int, to unsafe.Pointer, addrlen _Socklen) (err error)
 //sys	recvmsg(s int, msg *Msghdr, flags int) (n int, err error)
 
-func Recvmsg(fd int, p, oob []byte, flags int) (n, oobn int, recvflags int, from Sockaddr, err error) {
+func recvmsgRaw(fd int, p, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn int, recvflags int, err error) {
 	var msg Msghdr
-	var rsa RawSockaddrAny
+	msg.Name = (*byte)(unsafe.Pointer(rsa))
-	msg.Name = (*byte)(unsafe.Pointer(&rsa))
 	msg.Namelen = uint32(SizeofSockaddrAny)
 	var iov Iovec
 	if len(p) > 0 {
@@ -352,10 +351,6 @@ func Recvmsg(fd int, p, oob []byte, flags int) (n, oobn int, recvflags int, from
 	}
 	oobn = int(msg.Controllen)
 	recvflags = int(msg.Flags)
-	// source address is only specified if the socket is unconnected
-	if rsa.Addr.Family != AF_UNSPEC {
-		from, err = anyToSockaddr(fd, &rsa)
-	}
 	return
 }
 

unix/syscall_linux.go

@@ -1497,10 +1497,9 @@ func KeyctlRestrictKeyring(ringid int, keyType string, restriction string) error
 //sys	keyctlRestrictKeyringByType(cmd int, arg2 int, keyType string, restriction string) (err error) = SYS_KEYCTL
 //sys	keyctlRestrictKeyring(cmd int, arg2 int) (err error) = SYS_KEYCTL
 
-func Recvmsg(fd int, p, oob []byte, flags int) (n, oobn int, recvflags int, from Sockaddr, err error) {
+func recvmsgRaw(fd int, p, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn int, recvflags int, err error) {
 	var msg Msghdr
-	var rsa RawSockaddrAny
+	msg.Name = (*byte)(unsafe.Pointer(rsa))
-	msg.Name = (*byte)(unsafe.Pointer(&rsa))
 	msg.Namelen = uint32(SizeofSockaddrAny)
 	var iov Iovec
 	if len(p) > 0 {
@@ -1531,10 +1530,6 @@ func Recvmsg(fd int, p, oob []byte, flags int) (n, oobn int, recvflags int, from
 	}
 	oobn = int(msg.Controllen)
 	recvflags = int(msg.Flags)
-	// source address is only specified if the socket is unconnected
-	if rsa.Addr.Family != AF_UNSPEC {
-		from, err = anyToSockaddr(fd, &rsa)
-	}
 	return
 }
 

unix/syscall_solaris.go

@@ -451,10 +451,9 @@ func Accept(fd int) (nfd int, sa Sockaddr, err error) {
 
 //sys	recvmsg(s int, msg *Msghdr, flags int) (n int, err error) = libsocket.__xnet_recvmsg
 
-func Recvmsg(fd int, p, oob []byte, flags int) (n, oobn int, recvflags int, from Sockaddr, err error) {
+func recvmsgRaw(fd int, p, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn int, recvflags int, err error) {
 	var msg Msghdr
-	var rsa RawSockaddrAny
+	msg.Name = (*byte)(unsafe.Pointer(rsa))
-	msg.Name = (*byte)(unsafe.Pointer(&rsa))
 	msg.Namelen = uint32(SizeofSockaddrAny)
 	var iov Iovec
 	if len(p) > 0 {
@@ -476,10 +475,6 @@ func Recvmsg(fd int, p, oob []byte, flags int) (n, oobn int, recvflags int, from
 		return
 	}
 	oobn = int(msg.Accrightslen)
-	// source address is only specified if the socket is unconnected
-	if rsa.Addr.Family != AF_UNSPEC {
-		from, err = anyToSockaddr(fd, &rsa)
-	}
 	return
 }
 

unix/syscall_unix.go

@@ -337,6 +337,16 @@ func Recvfrom(fd int, p []byte, flags int) (n int, from Sockaddr, err error) {
 	return
 }
 
+func Recvmsg(fd int, p, oob []byte, flags int) (n, oobn int, recvflags int, from Sockaddr, err error) {
+	var rsa RawSockaddrAny
+	n, oobn, recvflags, err = recvmsgRaw(fd, p, oob, flags, &rsa)
+	// source address is only specified if the socket is unconnected
+	if rsa.Addr.Family != AF_UNSPEC {
+		from, err = anyToSockaddr(fd, &rsa)
+	}
+	return
+}
+
 func Sendmsg(fd int, p, oob []byte, to Sockaddr, flags int) (err error) {
 	_, err = SendmsgN(fd, p, oob, to, flags)
 	return