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//go:build linux
package examples
import (
"fmt"
"github.com/cilium/ebpf"
)
func DocLoadCollectionSpec() {
// Parse an ELF into a CollectionSpec.
// bpf_prog.o is the result of compiling BPF C code.
spec, err := ebpf.LoadCollectionSpec("bpf_prog.o")
if err != nil {
panic(err)
}
// Look up the MapSpec and ProgramSpec in the CollectionSpec.
m := spec.Maps["my_map"]
p := spec.Programs["my_prog"]
// Note: We've omitted nil checks for brevity, take a look at
// LoadAndAssign for an automated way of checking for maps/programs.
// Inspect the map and program type.
fmt.Println(m.Type, p.Type)
// Print the map's key and value BTF types.
fmt.Println(m.Key, m.Value)
// Print the program's instructions in a human-readable form,
// similar to llvm-objdump -S.
fmt.Println(p.Instructions)
}
func DocNewCollection() {
spec, err := ebpf.LoadCollectionSpec("bpf_prog.o")
if err != nil {
panic(err)
}
// Instantiate a Collection from a CollectionSpec.
coll, err := ebpf.NewCollection(spec)
if err != nil {
panic(err)
}
// Close the Collection before the enclosing function returns.
defer coll.Close()
// Obtain a reference to 'my_map'.
m := coll.Maps["my_map"]
// Set map key '1' to value '2'.
if err := m.Put(uint32(1), uint64(2)); err != nil {
panic(err)
}
}
// DocLoadAndAssignObjs {
type myObjs struct {
MyMap *ebpf.Map `ebpf:"my_map"`
MyProg *ebpf.Program `ebpf:"my_prog"`
}
func (objs *myObjs) Close() error {
if err := objs.MyMap.Close(); err != nil {
return err
}
if err := objs.MyProg.Close(); err != nil {
return err
}
return nil
}
// }
func DocLoadAndAssign() {
spec, err := ebpf.LoadCollectionSpec("bpf_prog.o")
if err != nil {
panic(err)
}
// Insert only the resources specified in 'obj' into the kernel and assign
// them to their respective fields. If any requested resources are not found
// in the ELF, this will fail. Any errors encountered while loading Maps or
// Programs will also be returned here.
var objs myObjs
if err := spec.LoadAndAssign(&objs, nil); err != nil {
panic(err)
}
defer objs.Close()
// Interact with MyMap through the custom struct.
if err := objs.MyMap.Put(uint32(1), uint64(2)); err != nil {
panic(err)
}
}
func DocBTFTypeByName() {
spec, err := ebpf.LoadCollectionSpec("bpf_prog.o")
if err != nil {
panic(err)
}
// Look up the __64 type declared in linux/bpf.h.
t, err := spec.Types.AnyTypeByName("__u64")
if err != nil {
panic(err)
}
fmt.Println(t)
}
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