Merge release-20201208.0-94-gffa9a715a (automated)

2 files changed, 222 insertions, 222 deletions

diff --git a/pkg/sentry/arch/arch_abi_autogen_unsafe.go b/pkg/sentry/arch/arch_abi_autogen_unsafe.go
index fe68f921d..2ddabb10b 100644
--- a/pkg/sentry/arch/arch_abi_autogen_unsafe.go
+++ b/pkg/sentry/arch/arch_abi_autogen_unsafe.go
@@ -23,71 +23,53 @@ var _ marshal.Marshallable = (*SignalStack)(nil)
 var _ marshal.Marshallable = (*linux.SignalSet)(nil)
 
 // SizeBytes implements marshal.Marshallable.SizeBytes.
-func (s *SignalAct) SizeBytes() int {
-    return 24 +
-        (*linux.SignalSet)(nil).SizeBytes()
+func (s *SignalStack) SizeBytes() int {
+    return 24
 }
 
 // MarshalBytes implements marshal.Marshallable.MarshalBytes.
-func (s *SignalAct) MarshalBytes(dst []byte) {
-    usermem.ByteOrder.PutUint64(dst[:8], uint64(s.Handler))
-    dst = dst[8:]
-    usermem.ByteOrder.PutUint64(dst[:8], uint64(s.Flags))
+func (s *SignalStack) MarshalBytes(dst []byte) {
+    usermem.ByteOrder.PutUint64(dst[:8], uint64(s.Addr))
     dst = dst[8:]
-    usermem.ByteOrder.PutUint64(dst[:8], uint64(s.Restorer))
+    usermem.ByteOrder.PutUint32(dst[:4], uint32(s.Flags))
+    dst = dst[4:]
+    // Padding: dst[:sizeof(uint32)] ~= uint32(0)
+    dst = dst[4:]
+    usermem.ByteOrder.PutUint64(dst[:8], uint64(s.Size))
     dst = dst[8:]
-    s.Mask.MarshalBytes(dst[:s.Mask.SizeBytes()])
-    dst = dst[s.Mask.SizeBytes():]
 }
 
 // UnmarshalBytes implements marshal.Marshallable.UnmarshalBytes.
-func (s *SignalAct) UnmarshalBytes(src []byte) {
-    s.Handler = uint64(usermem.ByteOrder.Uint64(src[:8]))
-    src = src[8:]
-    s.Flags = uint64(usermem.ByteOrder.Uint64(src[:8]))
+func (s *SignalStack) UnmarshalBytes(src []byte) {
+    s.Addr = uint64(usermem.ByteOrder.Uint64(src[:8]))
     src = src[8:]
-    s.Restorer = uint64(usermem.ByteOrder.Uint64(src[:8]))
+    s.Flags = uint32(usermem.ByteOrder.Uint32(src[:4]))
+    src = src[4:]
+    // Padding: var _ uint32 ~= src[:sizeof(uint32)]
+    src = src[4:]
+    s.Size = uint64(usermem.ByteOrder.Uint64(src[:8]))
     src = src[8:]
-    s.Mask.UnmarshalBytes(src[:s.Mask.SizeBytes()])
-    src = src[s.Mask.SizeBytes():]
 }
 
 // Packed implements marshal.Marshallable.Packed.
 //go:nosplit
-func (s *SignalAct) Packed() bool {
-    return s.Mask.Packed()
+func (s *SignalStack) Packed() bool {
+    return true
 }
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
-func (s *SignalAct) MarshalUnsafe(dst []byte) {
-    if s.Mask.Packed() {
-        safecopy.CopyIn(dst, unsafe.Pointer(s))
-    } else {
-        // Type SignalAct doesn't have a packed layout in memory, fallback to MarshalBytes.
-        s.MarshalBytes(dst)
-    }
+func (s *SignalStack) MarshalUnsafe(dst []byte) {
+    safecopy.CopyIn(dst, unsafe.Pointer(s))
 }
 
 // UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
-func (s *SignalAct) UnmarshalUnsafe(src []byte) {
-    if s.Mask.Packed() {
-        safecopy.CopyOut(unsafe.Pointer(s), src)
-    } else {
-        // Type SignalAct doesn't have a packed layout in memory, fallback to UnmarshalBytes.
-        s.UnmarshalBytes(src)
-    }
+func (s *SignalStack) UnmarshalUnsafe(src []byte) {
+    safecopy.CopyOut(unsafe.Pointer(s), src)
 }
 
 // CopyOutN implements marshal.Marshallable.CopyOutN.
 //go:nosplit
-func (s *SignalAct) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
-    if !s.Mask.Packed() {
-        // Type SignalAct doesn't have a packed layout in memory, fall back to MarshalBytes.
-        buf := cc.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
-        s.MarshalBytes(buf) // escapes: fallback.
-        return cc.CopyOutBytes(addr, buf[:limit]) // escapes: okay.
-    }
-
+func (s *SignalStack) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
     // Construct a slice backed by dst's underlying memory.
     var buf []byte
     hdr := (*reflect.SliceHeader)(unsafe.Pointer(&buf))
@@ -104,23 +86,13 @@ func (s *SignalAct) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit in
 
 // CopyOut implements marshal.Marshallable.CopyOut.
 //go:nosplit
-func (s *SignalAct) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
+func (s *SignalStack) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
     return s.CopyOutN(cc, addr, s.SizeBytes())
 }
 
 // CopyIn implements marshal.Marshallable.CopyIn.
 //go:nosplit
-func (s *SignalAct) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
-    if !s.Mask.Packed() {
-        // Type SignalAct doesn't have a packed layout in memory, fall back to UnmarshalBytes.
-        buf := cc.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
-        length, err := cc.CopyInBytes(addr, buf) // escapes: okay.
-        // Unmarshal unconditionally. If we had a short copy-in, this results in a
-        // partially unmarshalled struct.
-        s.UnmarshalBytes(buf) // escapes: fallback.
-        return length, err
-    }
-
+func (s *SignalStack) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
     // Construct a slice backed by dst's underlying memory.
     var buf []byte
     hdr := (*reflect.SliceHeader)(unsafe.Pointer(&buf))
@@ -136,15 +108,7 @@ func (s *SignalAct) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, erro
 }
 
 // WriteTo implements io.WriterTo.WriteTo.
-func (s *SignalAct) WriteTo(writer io.Writer) (int64, error) {
-    if !s.Mask.Packed() {
-        // Type SignalAct doesn't have a packed layout in memory, fall back to MarshalBytes.
-        buf := make([]byte, s.SizeBytes())
-        s.MarshalBytes(buf)
-        length, err := writer.Write(buf)
-        return int64(length), err
-    }
-
+func (s *SignalStack) WriteTo(writer io.Writer) (int64, error) {
     // Construct a slice backed by dst's underlying memory.
     var buf []byte
     hdr := (*reflect.SliceHeader)(unsafe.Pointer(&buf))
@@ -160,53 +124,62 @@ func (s *SignalAct) WriteTo(writer io.Writer) (int64, error) {
 }
 
 // SizeBytes implements marshal.Marshallable.SizeBytes.
-func (s *SignalStack) SizeBytes() int {
-    return 24
+func (s *SignalInfo) SizeBytes() int {
+    return 16 +
+        1*(128-16)
 }
 
 // MarshalBytes implements marshal.Marshallable.MarshalBytes.
-func (s *SignalStack) MarshalBytes(dst []byte) {
-    usermem.ByteOrder.PutUint64(dst[:8], uint64(s.Addr))
-    dst = dst[8:]
-    usermem.ByteOrder.PutUint32(dst[:4], uint32(s.Flags))
+func (s *SignalInfo) MarshalBytes(dst []byte) {
+    usermem.ByteOrder.PutUint32(dst[:4], uint32(s.Signo))
+    dst = dst[4:]
+    usermem.ByteOrder.PutUint32(dst[:4], uint32(s.Errno))
+    dst = dst[4:]
+    usermem.ByteOrder.PutUint32(dst[:4], uint32(s.Code))
     dst = dst[4:]
     // Padding: dst[:sizeof(uint32)] ~= uint32(0)
     dst = dst[4:]
-    usermem.ByteOrder.PutUint64(dst[:8], uint64(s.Size))
-    dst = dst[8:]
+    for idx := 0; idx < (128-16); idx++ {
+        dst[0] = byte(s.Fields[idx])
+        dst = dst[1:]
+    }
 }
 
 // UnmarshalBytes implements marshal.Marshallable.UnmarshalBytes.
-func (s *SignalStack) UnmarshalBytes(src []byte) {
-    s.Addr = uint64(usermem.ByteOrder.Uint64(src[:8]))
-    src = src[8:]
-    s.Flags = uint32(usermem.ByteOrder.Uint32(src[:4]))
+func (s *SignalInfo) UnmarshalBytes(src []byte) {
+    s.Signo = int32(usermem.ByteOrder.Uint32(src[:4]))
+    src = src[4:]
+    s.Errno = int32(usermem.ByteOrder.Uint32(src[:4]))
+    src = src[4:]
+    s.Code = int32(usermem.ByteOrder.Uint32(src[:4]))
     src = src[4:]
     // Padding: var _ uint32 ~= src[:sizeof(uint32)]
     src = src[4:]
-    s.Size = uint64(usermem.ByteOrder.Uint64(src[:8]))
-    src = src[8:]
+    for idx := 0; idx < (128-16); idx++ {
+        s.Fields[idx] = src[0]
+        src = src[1:]
+    }
 }
 
 // Packed implements marshal.Marshallable.Packed.
 //go:nosplit
-func (s *SignalStack) Packed() bool {
+func (s *SignalInfo) Packed() bool {
     return true
 }
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
-func (s *SignalStack) MarshalUnsafe(dst []byte) {
+func (s *SignalInfo) MarshalUnsafe(dst []byte) {
     safecopy.CopyIn(dst, unsafe.Pointer(s))
 }
 
 // UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
-func (s *SignalStack) UnmarshalUnsafe(src []byte) {
+func (s *SignalInfo) UnmarshalUnsafe(src []byte) {
     safecopy.CopyOut(unsafe.Pointer(s), src)
 }
 
 // CopyOutN implements marshal.Marshallable.CopyOutN.
 //go:nosplit
-func (s *SignalStack) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
+func (s *SignalInfo) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
     // Construct a slice backed by dst's underlying memory.
     var buf []byte
     hdr := (*reflect.SliceHeader)(unsafe.Pointer(&buf))
@@ -223,13 +196,13 @@ func (s *SignalStack) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit
 
 // CopyOut implements marshal.Marshallable.CopyOut.
 //go:nosplit
-func (s *SignalStack) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
+func (s *SignalInfo) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
     return s.CopyOutN(cc, addr, s.SizeBytes())
 }
 
 // CopyIn implements marshal.Marshallable.CopyIn.
 //go:nosplit
-func (s *SignalStack) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
+func (s *SignalInfo) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
     // Construct a slice backed by dst's underlying memory.
     var buf []byte
     hdr := (*reflect.SliceHeader)(unsafe.Pointer(&buf))
@@ -245,7 +218,7 @@ func (s *SignalStack) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, er
 }
 
 // WriteTo implements io.WriterTo.WriteTo.
-func (s *SignalStack) WriteTo(writer io.Writer) (int64, error) {
+func (s *SignalInfo) WriteTo(writer io.Writer) (int64, error) {
     // Construct a slice backed by dst's underlying memory.
     var buf []byte
     hdr := (*reflect.SliceHeader)(unsafe.Pointer(&buf))
@@ -261,62 +234,71 @@ func (s *SignalStack) WriteTo(writer io.Writer) (int64, error) {
 }
 
 // SizeBytes implements marshal.Marshallable.SizeBytes.
-func (s *SignalInfo) SizeBytes() int {
-    return 16 +
-        1*(128-16)
+func (s *SignalAct) SizeBytes() int {
+    return 24 +
+        (*linux.SignalSet)(nil).SizeBytes()
 }
 
 // MarshalBytes implements marshal.Marshallable.MarshalBytes.
-func (s *SignalInfo) MarshalBytes(dst []byte) {
-    usermem.ByteOrder.PutUint32(dst[:4], uint32(s.Signo))
-    dst = dst[4:]
-    usermem.ByteOrder.PutUint32(dst[:4], uint32(s.Errno))
-    dst = dst[4:]
-    usermem.ByteOrder.PutUint32(dst[:4], uint32(s.Code))
-    dst = dst[4:]
-    // Padding: dst[:sizeof(uint32)] ~= uint32(0)
-    dst = dst[4:]
-    for idx := 0; idx < (128-16); idx++ {
-        dst[0] = byte(s.Fields[idx])
-        dst = dst[1:]
-    }
+func (s *SignalAct) MarshalBytes(dst []byte) {
+    usermem.ByteOrder.PutUint64(dst[:8], uint64(s.Handler))
+    dst = dst[8:]
+    usermem.ByteOrder.PutUint64(dst[:8], uint64(s.Flags))
+    dst = dst[8:]
+    usermem.ByteOrder.PutUint64(dst[:8], uint64(s.Restorer))
+    dst = dst[8:]
+    s.Mask.MarshalBytes(dst[:s.Mask.SizeBytes()])
+    dst = dst[s.Mask.SizeBytes():]
 }
 
 // UnmarshalBytes implements marshal.Marshallable.UnmarshalBytes.
-func (s *SignalInfo) UnmarshalBytes(src []byte) {
-    s.Signo = int32(usermem.ByteOrder.Uint32(src[:4]))
-    src = src[4:]
-    s.Errno = int32(usermem.ByteOrder.Uint32(src[:4]))
-    src = src[4:]
-    s.Code = int32(usermem.ByteOrder.Uint32(src[:4]))
-    src = src[4:]
-    // Padding: var _ uint32 ~= src[:sizeof(uint32)]
-    src = src[4:]
-    for idx := 0; idx < (128-16); idx++ {
-        s.Fields[idx] = src[0]
-        src = src[1:]
-    }
+func (s *SignalAct) UnmarshalBytes(src []byte) {
+    s.Handler = uint64(usermem.ByteOrder.Uint64(src[:8]))
+    src = src[8:]
+    s.Flags = uint64(usermem.ByteOrder.Uint64(src[:8]))
+    src = src[8:]
+    s.Restorer = uint64(usermem.ByteOrder.Uint64(src[:8]))
+    src = src[8:]
+    s.Mask.UnmarshalBytes(src[:s.Mask.SizeBytes()])
+    src = src[s.Mask.SizeBytes():]
 }
 
 // Packed implements marshal.Marshallable.Packed.
 //go:nosplit
-func (s *SignalInfo) Packed() bool {
-    return true
+func (s *SignalAct) Packed() bool {
+    return s.Mask.Packed()
 }
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
-func (s *SignalInfo) MarshalUnsafe(dst []byte) {
-    safecopy.CopyIn(dst, unsafe.Pointer(s))
+func (s *SignalAct) MarshalUnsafe(dst []byte) {
+    if s.Mask.Packed() {
+        safecopy.CopyIn(dst, unsafe.Pointer(s))
+    } else {
+        // Type SignalAct doesn't have a packed layout in memory, fallback to MarshalBytes.
+        s.MarshalBytes(dst)
+    }
 }
 
 // UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
-func (s *SignalInfo) UnmarshalUnsafe(src []byte) {
-    safecopy.CopyOut(unsafe.Pointer(s), src)
+func (s *SignalAct) UnmarshalUnsafe(src []byte) {
+    if s.Mask.Packed() {
+        safecopy.CopyOut(unsafe.Pointer(s), src)
+    } else {
+        // Type SignalAct doesn't have a packed layout in memory, fallback to UnmarshalBytes.
+        s.UnmarshalBytes(src)
+    }
 }
 
 // CopyOutN implements marshal.Marshallable.CopyOutN.
 //go:nosplit
-func (s *SignalInfo) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
+func (s *SignalAct) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
+    if !s.Mask.Packed() {
+        // Type SignalAct doesn't have a packed layout in memory, fall back to MarshalBytes.
+        buf := cc.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
+        s.MarshalBytes(buf) // escapes: fallback.
+        return cc.CopyOutBytes(addr, buf[:limit]) // escapes: okay.
+    }
+
     // Construct a slice backed by dst's underlying memory.
     var buf []byte
     hdr := (*reflect.SliceHeader)(unsafe.Pointer(&buf))
@@ -333,13 +315,23 @@ func (s *SignalInfo) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit i
 
 // CopyOut implements marshal.Marshallable.CopyOut.
 //go:nosplit
-func (s *SignalInfo) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
+func (s *SignalAct) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
     return s.CopyOutN(cc, addr, s.SizeBytes())
 }
 
 // CopyIn implements marshal.Marshallable.CopyIn.
 //go:nosplit
-func (s *SignalInfo) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
+func (s *SignalAct) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
+    if !s.Mask.Packed() {
+        // Type SignalAct doesn't have a packed layout in memory, fall back to UnmarshalBytes.
+        buf := cc.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
+        length, err := cc.CopyInBytes(addr, buf) // escapes: okay.
+        // Unmarshal unconditionally. If we had a short copy-in, this results in a
+        // partially unmarshalled struct.
+        s.UnmarshalBytes(buf) // escapes: fallback.
+        return length, err
+    }
+
     // Construct a slice backed by dst's underlying memory.
     var buf []byte
     hdr := (*reflect.SliceHeader)(unsafe.Pointer(&buf))
@@ -355,7 +347,15 @@ func (s *SignalInfo) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, err
 }
 
 // WriteTo implements io.WriterTo.WriteTo.
-func (s *SignalInfo) WriteTo(writer io.Writer) (int64, error) {
+func (s *SignalAct) WriteTo(writer io.Writer) (int64, error) {
+    if !s.Mask.Packed() {
+        // Type SignalAct doesn't have a packed layout in memory, fall back to MarshalBytes.
+        buf := make([]byte, s.SizeBytes())
+        s.MarshalBytes(buf)
+        length, err := writer.Write(buf)
+        return int64(length), err
+    }
+
     // Construct a slice backed by dst's underlying memory.
     var buf []byte
     hdr := (*reflect.SliceHeader)(unsafe.Pointer(&buf))
diff --git a/pkg/sentry/syscalls/linux/vfs2/vfs2_abi_autogen_unsafe.go b/pkg/sentry/syscalls/linux/vfs2/vfs2_abi_autogen_unsafe.go
index ccd56285a..516ea1842 100644
--- a/pkg/sentry/syscalls/linux/vfs2/vfs2_abi_autogen_unsafe.go
+++ b/pkg/sentry/syscalls/linux/vfs2/vfs2_abi_autogen_unsafe.go
@@ -112,49 +112,26 @@ func (s *sigSetWithSize) WriteTo(writer io.Writer) (int64, error) {
 }
 
 // SizeBytes implements marshal.Marshallable.SizeBytes.
-func (m *MessageHeader64) SizeBytes() int {
-    return 56
+func (m *multipleMessageHeader64) SizeBytes() int {
+    return 8 +
+        (*MessageHeader64)(nil).SizeBytes()
 }
 
 // MarshalBytes implements marshal.Marshallable.MarshalBytes.
-func (m *MessageHeader64) MarshalBytes(dst []byte) {
-    usermem.ByteOrder.PutUint64(dst[:8], uint64(m.Name))
-    dst = dst[8:]
-    usermem.ByteOrder.PutUint32(dst[:4], uint32(m.NameLen))
-    dst = dst[4:]
-    // Padding: dst[:sizeof(uint32)] ~= uint32(0)
-    dst = dst[4:]
-    usermem.ByteOrder.PutUint64(dst[:8], uint64(m.Iov))
-    dst = dst[8:]
-    usermem.ByteOrder.PutUint64(dst[:8], uint64(m.IovLen))
-    dst = dst[8:]
-    usermem.ByteOrder.PutUint64(dst[:8], uint64(m.Control))
-    dst = dst[8:]
-    usermem.ByteOrder.PutUint64(dst[:8], uint64(m.ControlLen))
-    dst = dst[8:]
-    usermem.ByteOrder.PutUint32(dst[:4], uint32(m.Flags))
+func (m *multipleMessageHeader64) MarshalBytes(dst []byte) {
+    m.msgHdr.MarshalBytes(dst[:m.msgHdr.SizeBytes()])
+    dst = dst[m.msgHdr.SizeBytes():]
+    usermem.ByteOrder.PutUint32(dst[:4], uint32(m.msgLen))
     dst = dst[4:]
     // Padding: dst[:sizeof(int32)] ~= int32(0)
     dst = dst[4:]
 }
 
 // UnmarshalBytes implements marshal.Marshallable.UnmarshalBytes.
-func (m *MessageHeader64) UnmarshalBytes(src []byte) {
-    m.Name = uint64(usermem.ByteOrder.Uint64(src[:8]))
-    src = src[8:]
-    m.NameLen = uint32(usermem.ByteOrder.Uint32(src[:4]))
-    src = src[4:]
-    // Padding: var _ uint32 ~= src[:sizeof(uint32)]
-    src = src[4:]
-    m.Iov = uint64(usermem.ByteOrder.Uint64(src[:8]))
-    src = src[8:]
-    m.IovLen = uint64(usermem.ByteOrder.Uint64(src[:8]))
-    src = src[8:]
-    m.Control = uint64(usermem.ByteOrder.Uint64(src[:8]))
-    src = src[8:]
-    m.ControlLen = uint64(usermem.ByteOrder.Uint64(src[:8]))
-    src = src[8:]
-    m.Flags = int32(usermem.ByteOrder.Uint32(src[:4]))
+func (m *multipleMessageHeader64) UnmarshalBytes(src []byte) {
+    m.msgHdr.UnmarshalBytes(src[:m.msgHdr.SizeBytes()])
+    src = src[m.msgHdr.SizeBytes():]
+    m.msgLen = uint32(usermem.ByteOrder.Uint32(src[:4]))
     src = src[4:]
     // Padding: var _ int32 ~= src[:sizeof(int32)]
     src = src[4:]
@@ -162,23 +139,40 @@ func (m *MessageHeader64) UnmarshalBytes(src []byte) {
 
 // Packed implements marshal.Marshallable.Packed.
 //go:nosplit
-func (m *MessageHeader64) Packed() bool {
-    return true
+func (m *multipleMessageHeader64) Packed() bool {
+    return m.msgHdr.Packed()
 }
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
-func (m *MessageHeader64) MarshalUnsafe(dst []byte) {
-    safecopy.CopyIn(dst, unsafe.Pointer(m))
+func (m *multipleMessageHeader64) MarshalUnsafe(dst []byte) {
+    if m.msgHdr.Packed() {
+        safecopy.CopyIn(dst, unsafe.Pointer(m))
+    } else {
+        // Type multipleMessageHeader64 doesn't have a packed layout in memory, fallback to MarshalBytes.
+        m.MarshalBytes(dst)
+    }
 }
 
 // UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
-func (m *MessageHeader64) UnmarshalUnsafe(src []byte) {
-    safecopy.CopyOut(unsafe.Pointer(m), src)
+func (m *multipleMessageHeader64) UnmarshalUnsafe(src []byte) {
+    if m.msgHdr.Packed() {
+        safecopy.CopyOut(unsafe.Pointer(m), src)
+    } else {
+        // Type multipleMessageHeader64 doesn't have a packed layout in memory, fallback to UnmarshalBytes.
+        m.UnmarshalBytes(src)
+    }
 }
 
 // CopyOutN implements marshal.Marshallable.CopyOutN.
 //go:nosplit
-func (m *MessageHeader64) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
+func (m *multipleMessageHeader64) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
+    if !m.msgHdr.Packed() {
+        // Type multipleMessageHeader64 doesn't have a packed layout in memory, fall back to MarshalBytes.
+        buf := cc.CopyScratchBuffer(m.SizeBytes()) // escapes: okay.
+        m.MarshalBytes(buf) // escapes: fallback.
+        return cc.CopyOutBytes(addr, buf[:limit]) // escapes: okay.
+    }
+
     // Construct a slice backed by dst's underlying memory.
     var buf []byte
     hdr := (*reflect.SliceHeader)(unsafe.Pointer(&buf))
@@ -195,13 +189,23 @@ func (m *MessageHeader64) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, li
 
 // CopyOut implements marshal.Marshallable.CopyOut.
 //go:nosplit
-func (m *MessageHeader64) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
+func (m *multipleMessageHeader64) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
     return m.CopyOutN(cc, addr, m.SizeBytes())
 }
 
 // CopyIn implements marshal.Marshallable.CopyIn.
 //go:nosplit
-func (m *MessageHeader64) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
+func (m *multipleMessageHeader64) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
+    if !m.msgHdr.Packed() {
+        // Type multipleMessageHeader64 doesn't have a packed layout in memory, fall back to UnmarshalBytes.
+        buf := cc.CopyScratchBuffer(m.SizeBytes()) // escapes: okay.
+        length, err := cc.CopyInBytes(addr, buf) // escapes: okay.
+        // Unmarshal unconditionally. If we had a short copy-in, this results in a
+        // partially unmarshalled struct.
+        m.UnmarshalBytes(buf) // escapes: fallback.
+        return length, err
+    }
+
     // Construct a slice backed by dst's underlying memory.
     var buf []byte
     hdr := (*reflect.SliceHeader)(unsafe.Pointer(&buf))
@@ -217,7 +221,15 @@ func (m *MessageHeader64) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int
 }
 
 // WriteTo implements io.WriterTo.WriteTo.
-func (m *MessageHeader64) WriteTo(writer io.Writer) (int64, error) {
+func (m *multipleMessageHeader64) WriteTo(writer io.Writer) (int64, error) {
+    if !m.msgHdr.Packed() {
+        // Type multipleMessageHeader64 doesn't have a packed layout in memory, fall back to MarshalBytes.
+        buf := make([]byte, m.SizeBytes())
+        m.MarshalBytes(buf)
+        length, err := writer.Write(buf)
+        return int64(length), err
+    }
+
     // Construct a slice backed by dst's underlying memory.
     var buf []byte
     hdr := (*reflect.SliceHeader)(unsafe.Pointer(&buf))
@@ -233,26 +245,49 @@ func (m *MessageHeader64) WriteTo(writer io.Writer) (int64, error) {
 }
 
 // SizeBytes implements marshal.Marshallable.SizeBytes.
-func (m *multipleMessageHeader64) SizeBytes() int {
-    return 8 +
-        (*MessageHeader64)(nil).SizeBytes()
+func (m *MessageHeader64) SizeBytes() int {
+    return 56
 }
 
 // MarshalBytes implements marshal.Marshallable.MarshalBytes.
-func (m *multipleMessageHeader64) MarshalBytes(dst []byte) {
-    m.msgHdr.MarshalBytes(dst[:m.msgHdr.SizeBytes()])
-    dst = dst[m.msgHdr.SizeBytes():]
-    usermem.ByteOrder.PutUint32(dst[:4], uint32(m.msgLen))
+func (m *MessageHeader64) MarshalBytes(dst []byte) {
+    usermem.ByteOrder.PutUint64(dst[:8], uint64(m.Name))
+    dst = dst[8:]
+    usermem.ByteOrder.PutUint32(dst[:4], uint32(m.NameLen))
+    dst = dst[4:]
+    // Padding: dst[:sizeof(uint32)] ~= uint32(0)
+    dst = dst[4:]
+    usermem.ByteOrder.PutUint64(dst[:8], uint64(m.Iov))
+    dst = dst[8:]
+    usermem.ByteOrder.PutUint64(dst[:8], uint64(m.IovLen))
+    dst = dst[8:]
+    usermem.ByteOrder.PutUint64(dst[:8], uint64(m.Control))
+    dst = dst[8:]
+    usermem.ByteOrder.PutUint64(dst[:8], uint64(m.ControlLen))
+    dst = dst[8:]
+    usermem.ByteOrder.PutUint32(dst[:4], uint32(m.Flags))
     dst = dst[4:]
     // Padding: dst[:sizeof(int32)] ~= int32(0)
     dst = dst[4:]
 }
 
 // UnmarshalBytes implements marshal.Marshallable.UnmarshalBytes.
-func (m *multipleMessageHeader64) UnmarshalBytes(src []byte) {
-    m.msgHdr.UnmarshalBytes(src[:m.msgHdr.SizeBytes()])
-    src = src[m.msgHdr.SizeBytes():]
-    m.msgLen = uint32(usermem.ByteOrder.Uint32(src[:4]))
+func (m *MessageHeader64) UnmarshalBytes(src []byte) {
+    m.Name = uint64(usermem.ByteOrder.Uint64(src[:8]))
+    src = src[8:]
+    m.NameLen = uint32(usermem.ByteOrder.Uint32(src[:4]))
+    src = src[4:]
+    // Padding: var _ uint32 ~= src[:sizeof(uint32)]
+    src = src[4:]
+    m.Iov = uint64(usermem.ByteOrder.Uint64(src[:8]))
+    src = src[8:]
+    m.IovLen = uint64(usermem.ByteOrder.Uint64(src[:8]))
+    src = src[8:]
+    m.Control = uint64(usermem.ByteOrder.Uint64(src[:8]))
+    src = src[8:]
+    m.ControlLen = uint64(usermem.ByteOrder.Uint64(src[:8]))
+    src = src[8:]
+    m.Flags = int32(usermem.ByteOrder.Uint32(src[:4]))
     src = src[4:]
     // Padding: var _ int32 ~= src[:sizeof(int32)]
     src = src[4:]
@@ -260,40 +295,23 @@ func (m *multipleMessageHeader64) UnmarshalBytes(src []byte) {
 
 // Packed implements marshal.Marshallable.Packed.
 //go:nosplit
-func (m *multipleMessageHeader64) Packed() bool {
-    return m.msgHdr.Packed()
+func (m *MessageHeader64) Packed() bool {
+    return true
 }
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
-func (m *multipleMessageHeader64) MarshalUnsafe(dst []byte) {
-    if m.msgHdr.Packed() {
-        safecopy.CopyIn(dst, unsafe.Pointer(m))
-    } else {
-        // Type multipleMessageHeader64 doesn't have a packed layout in memory, fallback to MarshalBytes.
-        m.MarshalBytes(dst)
-    }
+func (m *MessageHeader64) MarshalUnsafe(dst []byte) {
+    safecopy.CopyIn(dst, unsafe.Pointer(m))
 }
 
 // UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
-func (m *multipleMessageHeader64) UnmarshalUnsafe(src []byte) {
-    if m.msgHdr.Packed() {
-        safecopy.CopyOut(unsafe.Pointer(m), src)
-    } else {
-        // Type multipleMessageHeader64 doesn't have a packed layout in memory, fallback to UnmarshalBytes.
-        m.UnmarshalBytes(src)
-    }
+func (m *MessageHeader64) UnmarshalUnsafe(src []byte) {
+    safecopy.CopyOut(unsafe.Pointer(m), src)
 }
 
 // CopyOutN implements marshal.Marshallable.CopyOutN.
 //go:nosplit
-func (m *multipleMessageHeader64) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
-    if !m.msgHdr.Packed() {
-        // Type multipleMessageHeader64 doesn't have a packed layout in memory, fall back to MarshalBytes.
-        buf := cc.CopyScratchBuffer(m.SizeBytes()) // escapes: okay.
-        m.MarshalBytes(buf) // escapes: fallback.
-        return cc.CopyOutBytes(addr, buf[:limit]) // escapes: okay.
-    }
-
+func (m *MessageHeader64) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
     // Construct a slice backed by dst's underlying memory.
     var buf []byte
     hdr := (*reflect.SliceHeader)(unsafe.Pointer(&buf))
@@ -310,23 +328,13 @@ func (m *multipleMessageHeader64) CopyOutN(cc marshal.CopyContext, addr usermem.
 
 // CopyOut implements marshal.Marshallable.CopyOut.
 //go:nosplit
-func (m *multipleMessageHeader64) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
+func (m *MessageHeader64) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
     return m.CopyOutN(cc, addr, m.SizeBytes())
 }
 
 // CopyIn implements marshal.Marshallable.CopyIn.
 //go:nosplit
-func (m *multipleMessageHeader64) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
-    if !m.msgHdr.Packed() {
-        // Type multipleMessageHeader64 doesn't have a packed layout in memory, fall back to UnmarshalBytes.
-        buf := cc.CopyScratchBuffer(m.SizeBytes()) // escapes: okay.
-        length, err := cc.CopyInBytes(addr, buf) // escapes: okay.
-        // Unmarshal unconditionally. If we had a short copy-in, this results in a
-        // partially unmarshalled struct.
-        m.UnmarshalBytes(buf) // escapes: fallback.
-        return length, err
-    }
-
+func (m *MessageHeader64) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
     // Construct a slice backed by dst's underlying memory.
     var buf []byte
     hdr := (*reflect.SliceHeader)(unsafe.Pointer(&buf))
@@ -342,15 +350,7 @@ func (m *multipleMessageHeader64) CopyIn(cc marshal.CopyContext, addr usermem.Ad
 }
 
 // WriteTo implements io.WriterTo.WriteTo.
-func (m *multipleMessageHeader64) WriteTo(writer io.Writer) (int64, error) {
-    if !m.msgHdr.Packed() {
-        // Type multipleMessageHeader64 doesn't have a packed layout in memory, fall back to MarshalBytes.
-        buf := make([]byte, m.SizeBytes())
-        m.MarshalBytes(buf)
-        length, err := writer.Write(buf)
-        return int64(length), err
-    }
-
+func (m *MessageHeader64) WriteTo(writer io.Writer) (int64, error) {
     // Construct a slice backed by dst's underlying memory.
     var buf []byte
     hdr := (*reflect.SliceHeader)(unsafe.Pointer(&buf))