github.com/inspektor-gadget/inspektor-gadget@v0.28.1/pkg/operators/ebpf/vars.go (about)

     1  // Copyright 2024 The Inspektor Gadget authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package ebpfoperator
    16  
    17  import (
    18  	"fmt"
    19  	"reflect"
    20  
    21  	"github.com/cilium/ebpf/btf"
    22  
    23  	"github.com/inspektor-gadget/inspektor-gadget/pkg/btfhelpers"
    24  )
    25  
    26  type ebpfVar struct {
    27  	name    string
    28  	refType reflect.Type
    29  	tags    []string
    30  }
    31  
    32  func (i *ebpfInstance) populateVar(t btf.Type, varName string) error {
    33  	btfVar, ok := t.(*btf.Var)
    34  	if !ok {
    35  		return fmt.Errorf("%q not of type *btf.Var", varName)
    36  	}
    37  
    38  	btfConst, ok := btfVar.Type.(*btf.Const)
    39  	if !ok {
    40  		return fmt.Errorf("%q not a const", varName)
    41  	}
    42  
    43  	btfVolatile, ok := btfConst.Type.(*btf.Volatile)
    44  	if !ok {
    45  		return fmt.Errorf("%q not volatile", varName)
    46  	}
    47  
    48  	refType, tags := btfhelpers.GetType(btfVolatile.Type)
    49  	if refType == nil {
    50  		i.logger.Warnf("unknown type for variable %q: %s (%T)", varName, btfVolatile.Type.TypeName(), btfVolatile.Type)
    51  		return nil
    52  	}
    53  
    54  	i.vars[varName] = &ebpfVar{
    55  		name:    varName,
    56  		refType: refType,
    57  		tags:    tags,
    58  	}
    59  
    60  	i.gadgetCtx.Logger().Debugf("variable %q %v %+v", varName, refType, t)
    61  	i.gadgetCtx.SetVar(varName, reflect.New(refType).Elem().Interface())
    62  	return nil
    63  }