Move Align{Up,Down} into binary package.

PiperOrigin-RevId: 294477647

6 files changed, 26 insertions, 40 deletions

diff --git a/pkg/binary/binary.go b/pkg/binary/binary.go
index 631785f7b..25065aef9 100644
--- a/pkg/binary/binary.go
+++ b/pkg/binary/binary.go
@@ -254,3 +254,13 @@ func WriteUint64(w io.Writer, order binary.ByteOrder, num uint64) error {
 	_, err := w.Write(buf)
 	return err
 }
+
+// AlignUp rounds a length up to an alignment. align must be a power of 2.
+func AlignUp(length int, align uint) int {
+	return (length + int(align) - 1) & ^(int(align) - 1)
+}
+
+// AlignDown rounds a length down to an alignment. align must be a power of 2.
+func AlignDown(length int, align uint) int {
+	return length & ^(int(align) - 1)
+}
diff --git a/pkg/sentry/socket/control/control.go b/pkg/sentry/socket/control/control.go
index 00265f15b..6145a7fc3 100644
--- a/pkg/sentry/socket/control/control.go
+++ b/pkg/sentry/socket/control/control.go
@@ -189,7 +189,7 @@ func putUint32(buf []byte, n uint32) []byte {
 // putCmsg writes a control message header and as much data as will fit into
 // the unused capacity of a buffer.
 func putCmsg(buf []byte, flags int, msgType uint32, align uint, data []int32) ([]byte, int) {
-	space := AlignDown(cap(buf)-len(buf), 4)
+	space := binary.AlignDown(cap(buf)-len(buf), 4)
 
 	// We can't write to space that doesn't exist, so if we are going to align
 	// the available space, we must align down.
@@ -282,19 +282,9 @@ func PackCredentials(t *kernel.Task, creds SCMCredentials, buf []byte, flags int
 	return putCmsg(buf, flags, linux.SCM_CREDENTIALS, align, c)
 }
 
-// AlignUp rounds a length up to an alignment. align must be a power of 2.
-func AlignUp(length int, align uint) int {
-	return (length + int(align) - 1) & ^(int(align) - 1)
-}
-
-// AlignDown rounds a down to an alignment. align must be a power of 2.
-func AlignDown(length int, align uint) int {
-	return length & ^(int(align) - 1)
-}
-
 // alignSlice extends a slice's length (up to the capacity) to align it.
 func alignSlice(buf []byte, align uint) []byte {
-	aligned := AlignUp(len(buf), align)
+	aligned := binary.AlignUp(len(buf), align)
 	if aligned > cap(buf) {
 		// Linux allows unaligned data if there isn't room for alignment.
 		// Since there isn't room for alignment, there isn't room for any
@@ -377,7 +367,7 @@ func PackControlMessages(t *kernel.Task, cmsgs socket.ControlMessages, buf []byt
 
 // cmsgSpace is equivalent to CMSG_SPACE in Linux.
 func cmsgSpace(t *kernel.Task, dataLen int) int {
-	return linux.SizeOfControlMessageHeader + AlignUp(dataLen, t.Arch().Width())
+	return linux.SizeOfControlMessageHeader + binary.AlignUp(dataLen, t.Arch().Width())
 }
 
 // CmsgsSpace returns the number of bytes needed to fit the control messages
@@ -437,7 +427,7 @@ func Parse(t *kernel.Task, socketOrEndpoint interface{}, buf []byte) (socket.Con
 		case linux.SOL_SOCKET:
 			switch h.Type {
 			case linux.SCM_RIGHTS:
-				rightsSize := AlignDown(length, linux.SizeOfControlMessageRight)
+				rightsSize := binary.AlignDown(length, linux.SizeOfControlMessageRight)
 				numRights := rightsSize / linux.SizeOfControlMessageRight
 
 				if len(fds)+numRights > linux.SCM_MAX_FD {
@@ -448,7 +438,7 @@ func Parse(t *kernel.Task, socketOrEndpoint interface{}, buf []byte) (socket.Con
 					fds = append(fds, int32(usermem.ByteOrder.Uint32(buf[j:j+linux.SizeOfControlMessageRight])))
 				}
 
-				i += AlignUp(length, width)
+				i += binary.AlignUp(length, width)
 
 			case linux.SCM_CREDENTIALS:
 				if length < linux.SizeOfControlMessageCredentials {
@@ -462,7 +452,7 @@ func Parse(t *kernel.Task, socketOrEndpoint interface{}, buf []byte) (socket.Con
 					return socket.ControlMessages{}, err
 				}
 				cmsgs.Unix.Credentials = scmCreds
-				i += AlignUp(length, width)
+				i += binary.AlignUp(length, width)
 
 			default:
 				// Unknown message type.
@@ -476,7 +466,7 @@ func Parse(t *kernel.Task, socketOrEndpoint interface{}, buf []byte) (socket.Con
 				}
 				cmsgs.IP.HasTOS = true
 				binary.Unmarshal(buf[i:i+linux.SizeOfControlMessageTOS], usermem.ByteOrder, &cmsgs.IP.TOS)
-				i += AlignUp(length, width)
+				i += binary.AlignUp(length, width)
 
 			default:
 				return socket.ControlMessages{}, syserror.EINVAL
@@ -489,7 +479,7 @@ func Parse(t *kernel.Task, socketOrEndpoint interface{}, buf []byte) (socket.Con
 				}
 				cmsgs.IP.HasTClass = true
 				binary.Unmarshal(buf[i:i+linux.SizeOfControlMessageTClass], usermem.ByteOrder, &cmsgs.IP.TClass)
-				i += AlignUp(length, width)
+				i += binary.AlignUp(length, width)
 
 			default:
 				return socket.ControlMessages{}, syserror.EINVAL
diff --git a/pkg/sentry/socket/netfilter/extensions.go b/pkg/sentry/socket/netfilter/extensions.go
index 22fd0ebe7..b4b244abf 100644
--- a/pkg/sentry/socket/netfilter/extensions.go
+++ b/pkg/sentry/socket/netfilter/extensions.go
@@ -72,7 +72,7 @@ func marshalEntryMatch(name string, data []byte) []byte {
 	nflog("marshaling matcher %q", name)
 
 	// We have to pad this struct size to a multiple of 8 bytes.
-	size := alignUp(linux.SizeOfXTEntryMatch+len(data), 8)
+	size := binary.AlignUp(linux.SizeOfXTEntryMatch+len(data), 8)
 	matcher := linux.KernelXTEntryMatch{
 		XTEntryMatch: linux.XTEntryMatch{
 			MatchSize: uint16(size),
@@ -93,8 +93,3 @@ func unmarshalMatcher(match linux.XTEntryMatch, filter iptables.IPHeaderFilter,
 	}
 	return matchMaker.unmarshal(buf, filter)
 }
-
-// alignUp rounds a length up to an alignment. align must be a power of 2.
-func alignUp(length int, align uint) int {
-	return (length + int(align) - 1) & ^(int(align) - 1)
-}
diff --git a/pkg/sentry/socket/netlink/message.go b/pkg/sentry/socket/netlink/message.go
index 4ea252ccb..0899c61d1 100644
--- a/pkg/sentry/socket/netlink/message.go
+++ b/pkg/sentry/socket/netlink/message.go
@@ -23,18 +23,11 @@ import (
 	"gvisor.dev/gvisor/pkg/usermem"
 )
 
-// alignUp rounds a length up to an alignment.
-//
-// Preconditions: align is a power of two.
-func alignUp(length int, align uint) int {
-	return (length + int(align) - 1) &^ (int(align) - 1)
-}
-
 // alignPad returns the length of padding required for alignment.
 //
 // Preconditions: align is a power of two.
 func alignPad(length int, align uint) int {
-	return alignUp(length, align) - length
+	return binary.AlignUp(length, align) - length
 }
 
 // Message contains a complete serialized netlink message.
@@ -138,7 +131,7 @@ func (m *Message) Finalize() []byte {
 	// Align the message. Note that the message length in the header (set
 	// above) is the useful length of the message, not the total aligned
 	// length. See net/netlink/af_netlink.c:__nlmsg_put.
-	aligned := alignUp(len(m.buf), linux.NLMSG_ALIGNTO)
+	aligned := binary.AlignUp(len(m.buf), linux.NLMSG_ALIGNTO)
 	m.putZeros(aligned - len(m.buf))
 	return m.buf
 }
@@ -173,7 +166,7 @@ func (m *Message) PutAttr(atype uint16, v interface{}) {
 	m.Put(v)
 
 	// Align the attribute.
-	aligned := alignUp(l, linux.NLA_ALIGNTO)
+	aligned := binary.AlignUp(l, linux.NLA_ALIGNTO)
 	m.putZeros(aligned - l)
 }
 
@@ -190,7 +183,7 @@ func (m *Message) PutAttrString(atype uint16, s string) {
 	m.putZeros(1)
 
 	// Align the attribute.
-	aligned := alignUp(l, linux.NLA_ALIGNTO)
+	aligned := binary.AlignUp(l, linux.NLA_ALIGNTO)
 	m.putZeros(aligned - l)
 }
 
diff --git a/pkg/sentry/strace/BUILD b/pkg/sentry/strace/BUILD
index 762a946fe..2f39a6f2b 100644
--- a/pkg/sentry/strace/BUILD
+++ b/pkg/sentry/strace/BUILD
@@ -30,7 +30,6 @@ go_library(
         "//pkg/seccomp",
         "//pkg/sentry/arch",
         "//pkg/sentry/kernel",
-        "//pkg/sentry/socket/control",
         "//pkg/sentry/socket/netlink",
         "//pkg/sentry/socket/netstack",
         "//pkg/sentry/syscalls/linux",
diff --git a/pkg/sentry/strace/socket.go b/pkg/sentry/strace/socket.go
index f7ff4573e..51e6d81b2 100644
--- a/pkg/sentry/strace/socket.go
+++ b/pkg/sentry/strace/socket.go
@@ -22,7 +22,6 @@ import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/binary"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
-	"gvisor.dev/gvisor/pkg/sentry/socket/control"
 	"gvisor.dev/gvisor/pkg/sentry/socket/netlink"
 	"gvisor.dev/gvisor/pkg/sentry/socket/netstack"
 	slinux "gvisor.dev/gvisor/pkg/sentry/syscalls/linux"
@@ -220,13 +219,13 @@ func cmsghdr(t *kernel.Task, addr usermem.Addr, length uint64, maxBytes uint64)
 
 		if skipData {
 			strs = append(strs, fmt.Sprintf("{level=%s, type=%s, length=%d}", level, typ, h.Length))
-			i += control.AlignUp(length, width)
+			i += binary.AlignUp(length, width)
 			continue
 		}
 
 		switch h.Type {
 		case linux.SCM_RIGHTS:
-			rightsSize := control.AlignDown(length, linux.SizeOfControlMessageRight)
+			rightsSize := binary.AlignDown(length, linux.SizeOfControlMessageRight)
 
 			numRights := rightsSize / linux.SizeOfControlMessageRight
 			fds := make(linux.ControlMessageRights, numRights)
@@ -295,7 +294,7 @@ func cmsghdr(t *kernel.Task, addr usermem.Addr, length uint64, maxBytes uint64)
 		default:
 			panic("unreachable")
 		}
-		i += control.AlignUp(length, width)
+		i += binary.AlignUp(length, width)
 	}
 
 	return fmt.Sprintf("%#x %s", addr, strings.Join(strs, ", "))