Method createStructOpsMap

elf_reader.go:1563–1605

createStructOpsMap() creates and registers a MapSpec for a struct_ops

(vsi btf.VarSecinfo, userData []byte, flags uint32)

// createStructOpsMap() creates and registers a MapSpec for a struct_ops
func (ec *elfCode) createStructOpsMap(vsi btf.VarSecinfo, userData []byte, flags uint32) (*btf.Struct, uint32, error) {
	varType, ok := btf.As[*btf.Var](vsi.Type)
	if !ok {
		return nil, 0, fmt.Errorf("vsi: expect var, got %T", vsi.Type)
	}

	mapName := varType.Name

	userSt, ok := btf.As[*btf.Struct](varType.Type)
	if !ok {
		return nil, 0, fmt.Errorf("var %s: expect struct, got %T", varType.Name, varType.Type)
	}

	userSize := userSt.Size
	baseOff := vsi.Offset
	if uint64(baseOff)+uint64(userSize) > uint64(len(userData)) {
		return nil, 0, fmt.Errorf("%s exceeds section", mapName)
	}

	// Register the MapSpec for this struct_ops instance if doesn't exist
	if _, exists := ec.maps[mapName]; exists {
		return nil, 0, fmt.Errorf("struct_ops map %s: already exists", mapName)
	}

	ec.maps[mapName] = &MapSpec{
		Name:       mapName,
		Type:       StructOpsMap,
		Key:        &btf.Int{Size: 4},
		KeySize:    structOpsKeySize,
		ValueSize:  userSize, // length of the user-struct type
		Value:      userSt,
		Flags:      flags,
		MaxEntries: 1,
		Contents: []MapKV{
			{
				Key:   uint32(0),
				Value: append([]byte(nil), userData[baseOff:baseOff+userSize]...),
			},
		},
	}

	return userSt, baseOff, nil
}

type libbpfElfSectionDef struct {
	pattern     string