fuse: remove unused marshalling functions

This commit removes unused marshalling functions in linux abi package
and moves self-defined FUSEInitRes wrapper to fuse package.

Updates #3707

4 files changed, 81 insertions, 177 deletions

diff --git a/pkg/abi/linux/fuse.go b/pkg/abi/linux/fuse.go
index ca4ee5e80..5616290a5 100644
--- a/pkg/abi/linux/fuse.go
+++ b/pkg/abi/linux/fuse.go
@@ -15,7 +15,6 @@
 package linux
 
 import (
-	"gvisor.dev/gvisor/pkg/usermem"
 	"gvisor.dev/gvisor/tools/go_marshal/marshal"
 	"gvisor.dev/gvisor/tools/go_marshal/primitive"
 )
@@ -263,63 +262,6 @@ type FUSEInitOut struct {
 	_ [8]uint32
 }
 
-// FUSEInitRes is a variable-length wrapper of FUSEInitOut. The FUSE server may
-// implement older version of FUSE protocol, which contains a FUSEInitOut with
-// less attributes.
-//
-// Dynamically-sized objects cannot be marshalled.
-type FUSEInitRes struct {
-	marshal.StubMarshallable
-
-	// InitOut contains the response from the FUSE server.
-	InitOut FUSEInitOut
-
-	// Len is the total length of bytes of the response.
-	Len uint32
-}
-
-// UnMarshalBytes deserializes src to the InitOut attribute in a FUSEInitRes.
-func (r *FUSEInitRes) UnmarshalBytes(src []byte) {
-	out := &r.InitOut
-
-	// Introduced before FUSE kernel version 7.13.
-	out.Major = uint32(usermem.ByteOrder.Uint32(src[:4]))
-	src = src[4:]
-	out.Minor = uint32(usermem.ByteOrder.Uint32(src[:4]))
-	src = src[4:]
-	out.MaxReadahead = uint32(usermem.ByteOrder.Uint32(src[:4]))
-	src = src[4:]
-	out.Flags = uint32(usermem.ByteOrder.Uint32(src[:4]))
-	src = src[4:]
-	out.MaxBackground = uint16(usermem.ByteOrder.Uint16(src[:2]))
-	src = src[2:]
-	out.CongestionThreshold = uint16(usermem.ByteOrder.Uint16(src[:2]))
-	src = src[2:]
-	out.MaxWrite = uint32(usermem.ByteOrder.Uint32(src[:4]))
-	src = src[4:]
-
-	// Introduced in FUSE kernel version 7.23.
-	if len(src) >= 4 {
-		out.TimeGran = uint32(usermem.ByteOrder.Uint32(src[:4]))
-		src = src[4:]
-	}
-	// Introduced in FUSE kernel version 7.28.
-	if len(src) >= 2 {
-		out.MaxPages = uint16(usermem.ByteOrder.Uint16(src[:2]))
-		src = src[2:]
-	}
-	// Introduced in FUSE kernel version 7.31.
-	if len(src) >= 2 {
-		out.MapAlignment = uint16(usermem.ByteOrder.Uint16(src[:2]))
-		src = src[2:]
-	}
-}
-
-// SizeBytes is the size of the payload of the FUSE_INIT response.
-func (r *FUSEInitRes) SizeBytes() int {
-	return int(r.Len)
-}
-
 // FUSEGetAttrIn is the request sent by the kernel to the daemon,
 // to get the attribute of a inode.
 //
@@ -415,11 +357,6 @@ type FUSELookupIn struct {
 	Name string
 }
 
-// MarshalUnsafe serializes r.name to the dst buffer.
-func (r *FUSELookupIn) MarshalUnsafe(buf []byte) {
-	copy(buf, r.Name)
-}
-
 // MarshalBytes serializes r.name to the dst buffer.
 func (r *FUSELookupIn) MarshalBytes(buf []byte) {
 	copy(buf, r.Name)
@@ -548,12 +485,6 @@ type FUSEMknodIn struct {
 	Name string
 }
 
-// MarshalUnsafe serializes r.MknodMeta and r.Name to the dst buffer.
-func (r *FUSEMknodIn) MarshalUnsafe(buf []byte) {
-	r.MknodMeta.MarshalUnsafe(buf[:r.MknodMeta.SizeBytes()])
-	copy(buf[r.MknodMeta.SizeBytes():], r.Name)
-}
-
 // MarshalBytes serializes r.MknodMeta and r.Name to the dst buffer.
 func (r *FUSEMknodIn) MarshalBytes(buf []byte) {
 	r.MknodMeta.MarshalBytes(buf[:r.MknodMeta.SizeBytes()])
@@ -580,13 +511,6 @@ type FUSESymLinkIn struct {
 	Target string
 }
 
-// MarshalUnsafe serializes r.Name and r.Target to the dst buffer.
-// Left null-termination at end of r.Name and r.Target.
-func (r *FUSESymLinkIn) MarshalUnsafe(buf []byte) {
-	copy(buf, r.Name)
-	copy(buf[len(r.Name)+1:], r.Target)
-}
-
 // MarshalBytes serializes r.Name and r.Target to the dst buffer.
 // Left null-termination at end of r.Name and r.Target.
 func (r *FUSESymLinkIn) MarshalBytes(buf []byte) {
@@ -603,9 +527,6 @@ func (r *FUSESymLinkIn) SizeBytes() int {
 // FUSEEmptyIn is used by operations without request body.
 type FUSEEmptyIn struct{ marshal.StubMarshallable }
 
-// MarshalUnsafe do nothing for marshal.
-func (r *FUSEEmptyIn) MarshalUnsafe(buf []byte) {}
-
 // MarshalBytes do nothing for marshal.
 func (r *FUSEEmptyIn) MarshalBytes(buf []byte) {}
 
@@ -640,12 +561,6 @@ type FUSEMkdirIn struct {
 	Name string
 }
 
-// MarshalUnsafe serializes r.MkdirMeta and r.Name to the dst buffer.
-func (r *FUSEMkdirIn) MarshalUnsafe(buf []byte) {
-	r.MkdirMeta.MarshalUnsafe(buf[:r.MkdirMeta.SizeBytes()])
-	copy(buf[r.MkdirMeta.SizeBytes():], r.Name)
-}
-
 // MarshalBytes serializes r.MkdirMeta and r.Name to the dst buffer.
 func (r *FUSEMkdirIn) MarshalBytes(buf []byte) {
 	r.MkdirMeta.MarshalBytes(buf[:r.MkdirMeta.SizeBytes()])
@@ -669,11 +584,6 @@ type FUSERmDirIn struct {
 	Name string
 }
 
-// MarshalUnsafe serializes r.name to the dst buffer.
-func (r *FUSERmDirIn) MarshalUnsafe(buf []byte) {
-	copy(buf, r.Name)
-}
-
 // MarshalBytes serializes r.name to the dst buffer.
 func (r *FUSERmDirIn) MarshalBytes(buf []byte) {
 	copy(buf, r.Name)
@@ -684,16 +594,6 @@ func (r *FUSERmDirIn) SizeBytes() int {
 	return len(r.Name) + 1
 }
 
-// UnmarshalUnsafe deserializes r.name from the src buffer.
-func (r *FUSERmDirIn) UnmarshalUnsafe(src []byte) {
-	r.Name = string(src)
-}
-
-// UnmarshalBytes deserializes r.name from the src buffer.
-func (r *FUSERmDirIn) UnmarshalBytes(src []byte) {
-	r.Name = string(src)
-}
-
 // FUSEDirents is a list of Dirents received from the FUSE daemon server.
 // It is used for FUSE_READDIR.
 //
@@ -736,22 +636,6 @@ type FUSEDirentMeta struct {
 	Type uint32
 }
 
-// MarshalUnsafe serializes FUSEDirents to the dst buffer.
-func (r *FUSEDirents) MarshalUnsafe(dst []byte) {
-	for _, dirent := range r.Dirents {
-		dirent.MarshalUnsafe(dst)
-		dst = dst[dirent.SizeBytes():]
-	}
-}
-
-// MarshalBytes serializes FUSEDirents to the dst buffer.
-func (r *FUSEDirents) MarshalBytes(dst []byte) {
-	for _, dirent := range r.Dirents {
-		dirent.MarshalBytes(dst)
-		dst = dst[dirent.SizeBytes():]
-	}
-}
-
 // SizeBytes is the size of the memory representation of FUSEDirents.
 func (r *FUSEDirents) SizeBytes() int {
 	var sizeBytes int
@@ -762,30 +646,6 @@ func (r *FUSEDirents) SizeBytes() int {
 	return sizeBytes
 }
 
-// UnmarshalUnsafe deserializes FUSEDirents from the src buffer.
-func (r *FUSEDirents) UnmarshalUnsafe(src []byte) {
-	for {
-		if len(src) <= (*FUSEDirentMeta)(nil).SizeBytes() {
-			break
-		}
-
-		// Its unclear how many dirents there are in src. Each dirent is dynamically
-		// sized and so we can't make assumptions about how many dirents we can allocate.
-		if r.Dirents == nil {
-			r.Dirents = make([]*FUSEDirent, 0)
-		}
-
-		// We have to allocate a struct for each dirent - there must be a better way
-		// to do this. Linux allocates 1 page to store all the dirents and then
-		// simply reads them from the page.
-		var dirent FUSEDirent
-		dirent.UnmarshalUnsafe(src)
-		r.Dirents = append(r.Dirents, &dirent)
-
-		src = src[dirent.SizeBytes():]
-	}
-}
-
 // UnmarshalBytes deserializes FUSEDirents from the src buffer.
 func (r *FUSEDirents) UnmarshalBytes(src []byte) {
 	for {
@@ -810,24 +670,6 @@ func (r *FUSEDirents) UnmarshalBytes(src []byte) {
 	}
 }
 
-// MarshalUnsafe serializes FUSEDirent to the dst buffer.
-func (r *FUSEDirent) MarshalUnsafe(dst []byte) {
-	r.Meta.MarshalUnsafe(dst)
-	dst = dst[r.Meta.SizeBytes():]
-
-	name := primitive.ByteSlice(r.Name)
-	name.MarshalUnsafe(dst)
-}
-
-// MarshalBytes serializes FUSEDirent to the dst buffer.
-func (r *FUSEDirent) MarshalBytes(dst []byte) {
-	r.Meta.MarshalBytes(dst)
-	dst = dst[r.Meta.SizeBytes():]
-
-	name := primitive.ByteSlice(r.Name)
-	name.MarshalBytes(dst)
-}
-
 // SizeBytes is the size of the memory representation of FUSEDirent.
 func (r *FUSEDirent) SizeBytes() int {
 	dataSize := r.Meta.SizeBytes() + len(r.Name)
@@ -838,23 +680,6 @@ func (r *FUSEDirent) SizeBytes() int {
 	return (dataSize + (FUSE_DIRENT_ALIGN - 1)) & ^(FUSE_DIRENT_ALIGN - 1)
 }
 
-// UnmarshalUnsafe deserializes FUSEDirent from the src buffer.
-func (r *FUSEDirent) UnmarshalUnsafe(src []byte) {
-	r.Meta.UnmarshalUnsafe(src)
-	src = src[r.Meta.SizeBytes():]
-
-	if r.Meta.NameLen > FUSE_NAME_MAX {
-		// The name is too long and therefore invalid. We don't
-		// need to unmarshal the name since it'll be thrown away.
-		return
-	}
-
-	buf := make([]byte, r.Meta.NameLen)
-	name := primitive.ByteSlice(buf)
-	name.UnmarshalUnsafe(src[:r.Meta.NameLen])
-	r.Name = string(name)
-}
-
 // UnmarshalBytes deserializes FUSEDirent from the src buffer.
 func (r *FUSEDirent) UnmarshalBytes(src []byte) {
 	r.Meta.UnmarshalBytes(src)
diff --git a/pkg/sentry/fsimpl/fuse/BUILD b/pkg/sentry/fsimpl/fuse/BUILD
index 241d50c3d..5085d0521 100644
--- a/pkg/sentry/fsimpl/fuse/BUILD
+++ b/pkg/sentry/fsimpl/fuse/BUILD
@@ -40,6 +40,7 @@ go_library(
         "register.go",
         "regular_file.go",
         "request_list.go",
+        "request_response.go",
     ],
     visibility = ["//pkg/sentry:internal"],
     deps = [
diff --git a/pkg/sentry/fsimpl/fuse/init.go b/pkg/sentry/fsimpl/fuse/init.go
index 6384cbbdb..256b6fb65 100644
--- a/pkg/sentry/fsimpl/fuse/init.go
+++ b/pkg/sentry/fsimpl/fuse/init.go
@@ -76,12 +76,12 @@ func (conn *connection) InitRecv(res *Response, hasSysAdminCap bool) error {
 		return err
 	}
 
-	initRes := linux.FUSEInitRes{Len: res.DataLen()}
+	initRes := fuseInitRes{initLen: res.DataLen()}
 	if err := res.UnmarshalPayload(&initRes); err != nil {
 		return err
 	}
 
-	return conn.initProcessReply(&initRes.InitOut, hasSysAdminCap)
+	return conn.initProcessReply(&initRes.initOut, hasSysAdminCap)
 }
 
 // Process the FUSE_INIT reply from the FUSE server.
diff --git a/pkg/sentry/fsimpl/fuse/request_response.go b/pkg/sentry/fsimpl/fuse/request_response.go
new file mode 100644
index 000000000..ae71b5e28
--- /dev/null
+++ b/pkg/sentry/fsimpl/fuse/request_response.go
@@ -0,0 +1,78 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package fuse
+
+import (
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/usermem"
+	"gvisor.dev/gvisor/tools/go_marshal/marshal"
+)
+
+// fuseInitRes is a variable-length wrapper of linux.FUSEInitOut. The FUSE
+// server may implement an older version of FUSE protocol, which contains a
+// linux.FUSEInitOut with less attributes.
+//
+// Dynamically-sized objects cannot be marshalled.
+type fuseInitRes struct {
+	marshal.StubMarshallable
+
+	// initOut contains the response from the FUSE server.
+	initOut linux.FUSEInitOut
+
+	// initLen is the total length of bytes of the response.
+	initLen uint32
+}
+
+// UnmarshalBytes deserializes src to the initOut attribute in a fuseInitRes.
+func (r *fuseInitRes) UnmarshalBytes(src []byte) {
+	out := &r.initOut
+
+	// Introduced before FUSE kernel version 7.13.
+	out.Major = uint32(usermem.ByteOrder.Uint32(src[:4]))
+	src = src[4:]
+	out.Minor = uint32(usermem.ByteOrder.Uint32(src[:4]))
+	src = src[4:]
+	out.MaxReadahead = uint32(usermem.ByteOrder.Uint32(src[:4]))
+	src = src[4:]
+	out.Flags = uint32(usermem.ByteOrder.Uint32(src[:4]))
+	src = src[4:]
+	out.MaxBackground = uint16(usermem.ByteOrder.Uint16(src[:2]))
+	src = src[2:]
+	out.CongestionThreshold = uint16(usermem.ByteOrder.Uint16(src[:2]))
+	src = src[2:]
+	out.MaxWrite = uint32(usermem.ByteOrder.Uint32(src[:4]))
+	src = src[4:]
+
+	// Introduced in FUSE kernel version 7.23.
+	if len(src) >= 4 {
+		out.TimeGran = uint32(usermem.ByteOrder.Uint32(src[:4]))
+		src = src[4:]
+	}
+	// Introduced in FUSE kernel version 7.28.
+	if len(src) >= 2 {
+		out.MaxPages = uint16(usermem.ByteOrder.Uint16(src[:2]))
+		src = src[2:]
+	}
+	// Introduced in FUSE kernel version 7.31.
+	if len(src) >= 2 {
+		out.MapAlignment = uint16(usermem.ByteOrder.Uint16(src[:2]))
+		src = src[2:]
+	}
+}
+
+// SizeBytes is the size of the payload of the FUSE_INIT response.
+func (r *fuseInitRes) SizeBytes() int {
+	return int(r.initLen)
+}