wip ti-mo please add this support code

Signed-off-by: Simone Magnani <[email protected]>

Author: smagnani96

collection.go

@@ -189,8 +189,8 @@ func (cs *CollectionSpec) RewriteConstants(consts map[string]interface{}) error
 // Returns an error if any of the eBPF objects can't be found, or
 // if the same MapSpec or ProgramSpec is assigned multiple times.
 func (cs *CollectionSpec) Assign(to interface{}) error {
-	// Assign() only supports assigning ProgramSpecs and MapSpecs,
-	// so doesn't load any resources into the kernel.
+	// Assign() only supports assigning ProgramSpecs, MapSpecs
+	// and VariableSpecs, so doesn't load any resources into the kernel.
 	getValue := func(typ reflect.Type, name string) (interface{}, error) {
 		switch typ {
 
@@ -206,6 +206,12 @@ func (cs *CollectionSpec) Assign(to interface{}) error {
 			}
 			return nil, fmt.Errorf("missing map %q", name)
 
+		case reflect.TypeOf((*VariableSpec)(nil)):
+			if m := cs.Variables[name]; m != nil {
+				return m, nil
+			}
+			return nil, fmt.Errorf("missing variable %q", name)
+
 		default:
 			return nil, fmt.Errorf("unsupported type %s", typ)
 		}
@@ -269,6 +275,11 @@ func (cs *CollectionSpec) LoadAndAssign(to interface{}, opts *CollectionOptions)
 			return loader.loadVariable(name)
 
 		default:
+			if typ.Kind() == reflect.Pointer && typ.Elem().ConvertibleTo(reflect.TypeOf((*Variable)(nil)).Elem()) {
+				assignedVars[name] = true
+				return loader.loadVariable(name)
+			}
+
 			return nil, fmt.Errorf("unsupported type %s", typ)
 		}
 	}
@@ -752,8 +763,8 @@ func (coll *Collection) Assign(to interface{}) error {
 	assignedProgs := make(map[string]bool)
 	assignedVars := make(map[string]bool)
 
-	// Assign() only transfers already-loaded Maps and Programs. No extra
-	// loading is done.
+	// Assign() only transfers already-loaded Maps, Programs and Variablees.
+	// No extra loading is done.
 	getValue := func(typ reflect.Type, name string) (interface{}, error) {
 		switch typ {
 
@@ -779,6 +790,15 @@ func (coll *Collection) Assign(to interface{}) error {
 			return nil, fmt.Errorf("missing variable %q", name)
 
 		default:
+			if typ.Kind() == reflect.Pointer && typ.Elem().ConvertibleTo(reflect.TypeOf((*Variable)(nil)).Elem()) {
+				assignedVars[name] = true
+				if v := coll.Variables[name]; v != nil {
+					assignedVars[name] = true
+					return v, nil
+				}
+				return nil, fmt.Errorf("missing variable %q", name)
+			}
+
 			return nil, fmt.Errorf("unsupported type %s", typ)
 		}
 	}

variable.go

@@ -2,6 +2,7 @@ package ebpf
 
 import (
 	"fmt"
+	"sync/atomic"
 
 	"github.com/cilium/ebpf/btf"
 	"github.com/cilium/ebpf/internal/sysenc"
@@ -177,3 +178,37 @@ func (v *Variable) Get(out any) error {
 
 	return nil
 }
+
+func (v *Variable) AtomicUint32() (r *Uint32, err error) {
+	if err := bounds(v.mm, v.offset, atomic.Uint32{}); err != nil {
+		return nil, fmt.Errorf("offset out of range: %w", err)
+	}
+	return &Uint32{reinterp[*atomic.Uint32](&v.mm.b[v.offset]), v.mm}, nil
+}
+
+// Uint64 returns a pointer to an atomic uint64 in the memory-mapped region at
+// offset off.
+func (v *Variable) AtomicUint64() (r *Uint64, err error) {
+	if err := bounds(v.mm, v.offset, atomic.Uint64{}); err != nil {
+		return nil, fmt.Errorf("offset out of range: %w", err)
+	}
+	return &Uint64{reinterp[*atomic.Uint64](&v.mm.b[v.offset]), v.mm}, nil
+}
+
+// Int32 returns a pointer to an atomic int32 in the memory-mapped region at
+// offset off.
+func (v *Variable) AtomicInt32() (r *Int32, err error) {
+	if err := bounds(v.mm, v.offset, atomic.Int32{}); err != nil {
+		return nil, fmt.Errorf("offset out of range: %w", err)
+	}
+	return &Int32{reinterp[*atomic.Int32](&v.mm.b[v.offset]), v.mm}, nil
+}
+
+// Int64 returns a pointer to an atomic int64 in the memory-mapped region at
+// offset off.
+func (v *Variable) AtomicInt64() (r *Int64, err error) {
+	if err := bounds(v.mm, v.offset, atomic.Int64{}); err != nil {
+		return nil, fmt.Errorf("offset out of range: %w", err)
+	}
+	return &Int64{reinterp[*atomic.Int64](&v.mm.b[v.offset]), v.mm}, nil
+}