Make {Un}Marshal{Bytes/Unsafe} return remaining buffer.

Change marshal.Marshallable method signatures to return the remaining buffer.
This makes it easier to implement these method manually. Without this, we would
have to manually do buffer shifting which is error prone.

tools/go_marshal/test:benchmark test does not show change in performance.
Additionally fixed some marshalling bugs in fsimpl/fuse.

Updated multiple callpoints to get rid of redundant slice indexing work and
simplified code using this new signature.

Updates #6450

PiperOrigin-RevId: 407857019

2 files changed, 10 insertions, 10 deletions

diff --git a/pkg/sentry/socket/hostinet/socket.go b/pkg/sentry/socket/hostinet/socket.go
index 6e2318f75..a31f3ebec 100644
--- a/pkg/sentry/socket/hostinet/socket.go
+++ b/pkg/sentry/socket/hostinet/socket.go
@@ -578,7 +578,7 @@ func parseUnixControlMessages(unixControlMessages []unix.SocketControlMessage) s
 			case linux.SO_TIMESTAMP:
 				controlMessages.IP.HasTimestamp = true
 				ts := linux.Timeval{}
-				ts.UnmarshalUnsafe(unixCmsg.Data[:linux.SizeOfTimeval])
+				ts.UnmarshalUnsafe(unixCmsg.Data)
 				controlMessages.IP.Timestamp = ts.ToTime()
 			}
 
@@ -587,18 +587,18 @@ func parseUnixControlMessages(unixControlMessages []unix.SocketControlMessage) s
 			case linux.IP_TOS:
 				controlMessages.IP.HasTOS = true
 				var tos primitive.Uint8
-				tos.UnmarshalUnsafe(unixCmsg.Data[:tos.SizeBytes()])
+				tos.UnmarshalUnsafe(unixCmsg.Data)
 				controlMessages.IP.TOS = uint8(tos)
 
 			case linux.IP_PKTINFO:
 				controlMessages.IP.HasIPPacketInfo = true
 				var packetInfo linux.ControlMessageIPPacketInfo
-				packetInfo.UnmarshalUnsafe(unixCmsg.Data[:packetInfo.SizeBytes()])
+				packetInfo.UnmarshalUnsafe(unixCmsg.Data)
 				controlMessages.IP.PacketInfo = packetInfo
 
 			case linux.IP_RECVORIGDSTADDR:
 				var addr linux.SockAddrInet
-				addr.UnmarshalUnsafe(unixCmsg.Data[:addr.SizeBytes()])
+				addr.UnmarshalUnsafe(unixCmsg.Data)
 				controlMessages.IP.OriginalDstAddress = &addr
 
 			case unix.IP_RECVERR:
@@ -612,12 +612,12 @@ func parseUnixControlMessages(unixControlMessages []unix.SocketControlMessage) s
 			case linux.IPV6_TCLASS:
 				controlMessages.IP.HasTClass = true
 				var tclass primitive.Uint32
-				tclass.UnmarshalUnsafe(unixCmsg.Data[:tclass.SizeBytes()])
+				tclass.UnmarshalUnsafe(unixCmsg.Data)
 				controlMessages.IP.TClass = uint32(tclass)
 
 			case linux.IPV6_RECVORIGDSTADDR:
 				var addr linux.SockAddrInet6
-				addr.UnmarshalUnsafe(unixCmsg.Data[:addr.SizeBytes()])
+				addr.UnmarshalUnsafe(unixCmsg.Data)
 				controlMessages.IP.OriginalDstAddress = &addr
 
 			case unix.IPV6_RECVERR:
@@ -631,7 +631,7 @@ func parseUnixControlMessages(unixControlMessages []unix.SocketControlMessage) s
 			case linux.TCP_INQ:
 				controlMessages.IP.HasInq = true
 				var inq primitive.Int32
-				inq.UnmarshalUnsafe(unixCmsg.Data[:linux.SizeOfControlMessageInq])
+				inq.UnmarshalUnsafe(unixCmsg.Data)
 				controlMessages.IP.Inq = int32(inq)
 			}
 		}
diff --git a/pkg/sentry/socket/hostinet/stack.go b/pkg/sentry/socket/hostinet/stack.go
index 61111ac6c..c84ab3fb7 100644
--- a/pkg/sentry/socket/hostinet/stack.go
+++ b/pkg/sentry/socket/hostinet/stack.go
@@ -138,7 +138,7 @@ func ExtractHostInterfaces(links []syscall.NetlinkMessage, addrs []syscall.Netli
 			return fmt.Errorf("RTM_GETLINK returned RTM_NEWLINK message with invalid data length (%d bytes, expected at least %d bytes)", len(link.Data), unix.SizeofIfInfomsg)
 		}
 		var ifinfo linux.InterfaceInfoMessage
-		ifinfo.UnmarshalUnsafe(link.Data[:ifinfo.SizeBytes()])
+		ifinfo.UnmarshalUnsafe(link.Data)
 		inetIF := inet.Interface{
 			DeviceType: ifinfo.Type,
 			Flags:      ifinfo.Flags,
@@ -169,7 +169,7 @@ func ExtractHostInterfaces(links []syscall.NetlinkMessage, addrs []syscall.Netli
 			return fmt.Errorf("RTM_GETADDR returned RTM_NEWADDR message with invalid data length (%d bytes, expected at least %d bytes)", len(addr.Data), unix.SizeofIfAddrmsg)
 		}
 		var ifaddr linux.InterfaceAddrMessage
-		ifaddr.UnmarshalUnsafe(addr.Data[:ifaddr.SizeBytes()])
+		ifaddr.UnmarshalUnsafe(addr.Data)
 		inetAddr := inet.InterfaceAddr{
 			Family:    ifaddr.Family,
 			PrefixLen: ifaddr.PrefixLen,
@@ -201,7 +201,7 @@ func ExtractHostRoutes(routeMsgs []syscall.NetlinkMessage) ([]inet.Route, error)
 		}
 
 		var ifRoute linux.RouteMessage
-		ifRoute.UnmarshalUnsafe(routeMsg.Data[:ifRoute.SizeBytes()])
+		ifRoute.UnmarshalUnsafe(routeMsg.Data)
 		inetRoute := inet.Route{
 			Family:   ifRoute.Family,
 			DstLen:   ifRoute.DstLen,