Currently, when marshalig Go types with keyed union fields, we assign the
value of the struct (e.g. DomainBuildInfoTypeUnionHvm) which implements the
interface of the keyed union field (e.g. DomainBuildInfoTypeUnion).
As-is, this means that if a populated DomainBuildInfo is marshaled to
e.g. JSON, unmarshaling back to DomainBuildInfo will fail.
When the encoding/json is unmarshaling data into a Go type, and
encounters a JSON object, it basically can either marshal the data into
an empty interface, a map, or a struct. It cannot, however, marshal data
into an interface with at least one method defined on it (e.g.
DomainBuildInfoTypeUnion). Before this check is done, however, the
decoder will check if the Go type is a pointer, and dereference it if
so. It will then use the type of this value as the "target" type.
This means that if the TypeUnion field is populated with a
DomainBuildInfoTypeUnion, the decoder will see a non-empty interface and
fail. If the TypeUnion field is populated with a
*DomainBuildInfoTypeUnionHvm, it dereferences the pointer and sees a
struct instead, allowing decoding to continue normally.
Since there does not appear to be a strict need for NOT using pointers
in these fields, update code generation to set keyed union fields to
pointers of their implementing structs.
Signed-off-by: Nick Rosbrook <rosbro...@ainfosec.com>
---
tools/golang/xenlight/gengotypes.py | 4 +--
tools/golang/xenlight/helpers.gen.go | 44 ++++++++++++++--------------
2 files changed, 24 insertions(+), 24 deletions(-)
diff --git a/tools/golang/xenlight/gengotypes.py
b/tools/golang/xenlight/gengotypes.py
index 3796632f7d..57f2576468 100644
--- a/tools/golang/xenlight/gengotypes.py
+++ b/tools/golang/xenlight/gengotypes.py
@@ -404,7 +404,7 @@ def xenlight_golang_union_from_C(ty = None, union_name =
'', struct_name = ''):
s += 'if err := {0}.fromC(xc);'.format(goname)
s += 'err != nil {{\n return fmt.Errorf("converting field {0}: %v",
err)\n}}\n'.format(goname)
- s += 'x.{0} = {1}\n'.format(field_name, goname)
+ s += 'x.{0} = &{1}\n'.format(field_name, goname)
# End switch statement
s += 'default:\n'
@@ -571,7 +571,7 @@ def xenlight_golang_union_to_C(ty = None, union_name = '',
gotype = xenlight_golang_fmt_name(cgotype)
field_name = xenlight_golang_fmt_name('{0}_union'.format(keyname))
- s += 'tmp, ok := x.{0}.({1})\n'.format(field_name,gotype)
+ s += 'tmp, ok := x.{0}.(*{1})\n'.format(field_name,gotype)
s += 'if !ok {\n'
s += 'return errors.New("wrong type for union key
{0}")\n'.format(keyname)
s += '}\n'
diff --git a/tools/golang/xenlight/helpers.gen.go
b/tools/golang/xenlight/helpers.gen.go
index 5222898fb8..8fc5ec1649 100644
--- a/tools/golang/xenlight/helpers.gen.go
+++ b/tools/golang/xenlight/helpers.gen.go
@@ -443,7 +443,7 @@ var connectionPty ChannelinfoConnectionUnionPty
if err := connectionPty.fromC(xc);err != nil {
return fmt.Errorf("converting field connectionPty: %v", err)
}
-x.ConnectionUnion = connectionPty
+x.ConnectionUnion = &connectionPty
case ChannelConnectionSocket:
x.ConnectionUnion = nil
case ChannelConnectionUnknown:
@@ -485,7 +485,7 @@ switch x.Connection{
case ChannelConnectionUnknown:
break
case ChannelConnectionPty:
-tmp, ok := x.ConnectionUnion.(ChannelinfoConnectionUnionPty)
+tmp, ok := x.ConnectionUnion.(*ChannelinfoConnectionUnionPty)
if !ok {
return errors.New("wrong type for union key connection")
}
@@ -1120,7 +1120,7 @@ var typeHvm DomainBuildInfoTypeUnionHvm
if err := typeHvm.fromC(xc);err != nil {
return fmt.Errorf("converting field typeHvm: %v", err)
}
-x.TypeUnion = typeHvm
+x.TypeUnion = &typeHvm
case DomainTypeInvalid:
x.TypeUnion = nil
case DomainTypePv:
@@ -1128,13 +1128,13 @@ var typePv DomainBuildInfoTypeUnionPv
if err := typePv.fromC(xc);err != nil {
return fmt.Errorf("converting field typePv: %v", err)
}
-x.TypeUnion = typePv
+x.TypeUnion = &typePv
case DomainTypePvh:
var typePvh DomainBuildInfoTypeUnionPvh
if err := typePvh.fromC(xc);err != nil {
return fmt.Errorf("converting field typePvh: %v", err)
}
-x.TypeUnion = typePvh
+x.TypeUnion = &typePvh
default:
return fmt.Errorf("invalid union key '%v'", x.Type)}
x.ArchArm.GicVersion = GicVersion(xc.arch_arm.gic_version)
@@ -1465,7 +1465,7 @@ xc.tee = C.libxl_tee_type(x.Tee)
xc._type = C.libxl_domain_type(x.Type)
switch x.Type{
case DomainTypeHvm:
-tmp, ok := x.TypeUnion.(DomainBuildInfoTypeUnionHvm)
+tmp, ok := x.TypeUnion.(*DomainBuildInfoTypeUnionHvm)
if !ok {
return errors.New("wrong type for union key type")
}
@@ -1593,7 +1593,7 @@ hvm.mca_caps = C.uint64_t(tmp.McaCaps)
hvmBytes :=
C.GoBytes(unsafe.Pointer(&hvm),C.sizeof_libxl_domain_build_info_type_union_hvm)
copy(xc.u[:],hvmBytes)
case DomainTypePv:
-tmp, ok := x.TypeUnion.(DomainBuildInfoTypeUnionPv)
+tmp, ok := x.TypeUnion.(*DomainBuildInfoTypeUnionPv)
if !ok {
return errors.New("wrong type for union key type")
}
@@ -1623,7 +1623,7 @@ return fmt.Errorf("converting field E820Host: %v", err)
pvBytes :=
C.GoBytes(unsafe.Pointer(&pv),C.sizeof_libxl_domain_build_info_type_union_pv)
copy(xc.u[:],pvBytes)
case DomainTypePvh:
-tmp, ok := x.TypeUnion.(DomainBuildInfoTypeUnionPvh)
+tmp, ok := x.TypeUnion.(*DomainBuildInfoTypeUnionPvh)
if !ok {
return errors.New("wrong type for union key type")
}
@@ -2283,7 +2283,7 @@ var typeHostdev DeviceUsbdevTypeUnionHostdev
if err := typeHostdev.fromC(xc);err != nil {
return fmt.Errorf("converting field typeHostdev: %v", err)
}
-x.TypeUnion = typeHostdev
+x.TypeUnion = &typeHostdev
default:
return fmt.Errorf("invalid union key '%v'", x.Type)}
@@ -2310,7 +2310,7 @@ xc.port = C.int(x.Port)
xc._type = C.libxl_usbdev_type(x.Type)
switch x.Type{
case UsbdevTypeHostdev:
-tmp, ok := x.TypeUnion.(DeviceUsbdevTypeUnionHostdev)
+tmp, ok := x.TypeUnion.(*DeviceUsbdevTypeUnionHostdev)
if !ok {
return errors.New("wrong type for union key type")
}
@@ -2508,7 +2508,7 @@ var connectionSocket DeviceChannelConnectionUnionSocket
if err := connectionSocket.fromC(xc);err != nil {
return fmt.Errorf("converting field connectionSocket: %v", err)
}
-x.ConnectionUnion = connectionSocket
+x.ConnectionUnion = &connectionSocket
case ChannelConnectionUnknown:
x.ConnectionUnion = nil
default:
@@ -2546,7 +2546,7 @@ break
case ChannelConnectionPty:
break
case ChannelConnectionSocket:
-tmp, ok := x.ConnectionUnion.(DeviceChannelConnectionUnionSocket)
+tmp, ok := x.ConnectionUnion.(*DeviceChannelConnectionUnionSocket)
if !ok {
return errors.New("wrong type for union key connection")
}
@@ -4107,7 +4107,7 @@ var typeDiskEject EventTypeUnionDiskEject
if err := typeDiskEject.fromC(xc);err != nil {
return fmt.Errorf("converting field typeDiskEject: %v", err)
}
-x.TypeUnion = typeDiskEject
+x.TypeUnion = &typeDiskEject
case EventTypeDomainCreateConsoleAvailable:
x.TypeUnion = nil
case EventTypeDomainDeath:
@@ -4117,13 +4117,13 @@ var typeDomainShutdown EventTypeUnionDomainShutdown
if err := typeDomainShutdown.fromC(xc);err != nil {
return fmt.Errorf("converting field typeDomainShutdown: %v", err)
}
-x.TypeUnion = typeDomainShutdown
+x.TypeUnion = &typeDomainShutdown
case EventTypeOperationComplete:
var typeOperationComplete EventTypeUnionOperationComplete
if err := typeOperationComplete.fromC(xc);err != nil {
return fmt.Errorf("converting field typeOperationComplete: %v", err)
}
-x.TypeUnion = typeOperationComplete
+x.TypeUnion = &typeOperationComplete
default:
return fmt.Errorf("invalid union key '%v'", x.Type)}
@@ -4178,7 +4178,7 @@ xc.for_user = C.uint64_t(x.ForUser)
xc._type = C.libxl_event_type(x.Type)
switch x.Type{
case EventTypeDomainShutdown:
-tmp, ok := x.TypeUnion.(EventTypeUnionDomainShutdown)
+tmp, ok := x.TypeUnion.(*EventTypeUnionDomainShutdown)
if !ok {
return errors.New("wrong type for union key type")
}
@@ -4189,7 +4189,7 @@ copy(xc.u[:],domain_shutdownBytes)
case EventTypeDomainDeath:
break
case EventTypeDiskEject:
-tmp, ok := x.TypeUnion.(EventTypeUnionDiskEject)
+tmp, ok := x.TypeUnion.(*EventTypeUnionDiskEject)
if !ok {
return errors.New("wrong type for union key type")
}
@@ -4203,7 +4203,7 @@ return fmt.Errorf("converting field Disk: %v", err)
disk_ejectBytes :=
C.GoBytes(unsafe.Pointer(&disk_eject),C.sizeof_libxl_event_type_union_disk_eject)
copy(xc.u[:],disk_ejectBytes)
case EventTypeOperationComplete:
-tmp, ok := x.TypeUnion.(EventTypeUnionOperationComplete)
+tmp, ok := x.TypeUnion.(*EventTypeUnionOperationComplete)
if !ok {
return errors.New("wrong type for union key type")
}
@@ -4278,13 +4278,13 @@ var typeCat PsrHwInfoTypeUnionCat
if err := typeCat.fromC(xc);err != nil {
return fmt.Errorf("converting field typeCat: %v", err)
}
-x.TypeUnion = typeCat
+x.TypeUnion = &typeCat
case PsrFeatTypeMba:
var typeMba PsrHwInfoTypeUnionMba
if err := typeMba.fromC(xc);err != nil {
return fmt.Errorf("converting field typeMba: %v", err)
}
-x.TypeUnion = typeMba
+x.TypeUnion = &typeMba
default:
return fmt.Errorf("invalid union key '%v'", x.Type)}
@@ -4323,7 +4323,7 @@ xc.id = C.uint32_t(x.Id)
xc._type = C.libxl_psr_feat_type(x.Type)
switch x.Type{
case PsrFeatTypeCat:
-tmp, ok := x.TypeUnion.(PsrHwInfoTypeUnionCat)
+tmp, ok := x.TypeUnion.(*PsrHwInfoTypeUnionCat)
if !ok {
return errors.New("wrong type for union key type")
}
@@ -4334,7 +4334,7 @@ cat.cdp_enabled = C.bool(tmp.CdpEnabled)
catBytes :=
C.GoBytes(unsafe.Pointer(&cat),C.sizeof_libxl_psr_hw_info_type_union_cat)
copy(xc.u[:],catBytes)
case PsrFeatTypeMba:
-tmp, ok := x.TypeUnion.(PsrHwInfoTypeUnionMba)
+tmp, ok := x.TypeUnion.(*PsrHwInfoTypeUnionMba)
if !ok {
return errors.New("wrong type for union key type")
}
--
2.17.1
