syscall: unify unix Recvmsg epilogues

These were identical. This is a preliminary step
towards remove allocs per UDP receive.

Change-Id: I83106cd3f1fe4bc5bae2d1b0ebd23eedd820abed
Reviewed-on: https://go-review.googlesource.com/c/go/+/361258
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

5 files changed, 18 insertions, 28 deletions

diff --git a/src/syscall/syscall_aix.go b/src/syscall/syscall_aix.go
index 36172cc678..0f5101999f 100644
--- a/src/syscall/syscall_aix.go
+++ b/src/syscall/syscall_aix.go
@@ -321,10 +321,9 @@ 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) {
 	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 {
@@ -353,10 +352,6 @@ 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(&rsa)
-	}
 	return
 }
 
diff --git a/src/syscall/syscall_bsd.go b/src/syscall/syscall_bsd.go
index 71a331d6c0..5e636d5258 100644
--- a/src/syscall/syscall_bsd.go
+++ b/src/syscall/syscall_bsd.go
@@ -358,10 +358,9 @@ func GetsockoptICMPv6Filter(fd, level, opt int) (*ICMPv6Filter, 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 {
@@ -385,10 +384,6 @@ 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(&rsa)
-	}
 	return
 }
 
diff --git a/src/syscall/syscall_linux.go b/src/syscall/syscall_linux.go
index 695ce2b198..c002299641 100644
--- a/src/syscall/syscall_linux.go
+++ b/src/syscall/syscall_linux.go
@@ -638,10 +638,9 @@ func SetsockoptIPMreqn(fd, level, opt int, mreq *IPMreqn) (err error) {
 	return setsockopt(fd, level, opt, unsafe.Pointer(mreq), unsafe.Sizeof(*mreq))
 }
 
-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 {
@@ -672,10 +671,6 @@ 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(&rsa)
-	}
 	return
 }
 
diff --git a/src/syscall/syscall_solaris.go b/src/syscall/syscall_solaris.go
index 15b3c2bb40..5f12f229c4 100644
--- a/src/syscall/syscall_solaris.go
+++ b/src/syscall/syscall_solaris.go
@@ -332,10 +332,9 @@ 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) {
 	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 {
@@ -358,10 +357,6 @@ 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(&rsa)
-	}
 	return
 }
 
diff --git a/src/syscall/syscall_unix.go b/src/syscall/syscall_unix.go
index 2837c976e3..d1ecc361c6 100644
--- a/src/syscall/syscall_unix.go
+++ b/src/syscall/syscall_unix.go
@@ -324,6 +324,16 @@ func recvfromInet6(fd int, p []byte, flags int, from *SockaddrInet6) (n int, err
 	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(&rsa)
+	}
+	return
+}
+
 func Sendmsg(fd int, p, oob []byte, to Sockaddr, flags int) (err error) {
 	_, err = SendmsgN(fd, p, oob, to, flags)
 	return