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package link
import (
"fmt"
"io"
"github.com/cilium/ebpf"
)
type IterOptions struct {
// Program must be of type Tracing with attach type
// AttachTraceIter. The kind of iterator to attach to is
// determined at load time via the AttachTo field.
//
// AttachTo requires the kernel to include BTF of itself,
// and it to be compiled with a recent pahole (>= 1.16).
Program *ebpf.Program
}
// AttachIter attaches a BPF seq_file iterator.
func AttachIter(opts IterOptions) (*Iter, error) {
link, err := AttachRawLink(RawLinkOptions{
Program: opts.Program,
Attach: ebpf.AttachTraceIter,
})
if err != nil {
return nil, fmt.Errorf("can't link iterator: %w", err)
}
return &Iter{link}, err
}
// LoadPinnedIter loads a pinned iterator from a bpffs.
func LoadPinnedIter(fileName string) (*Iter, error) {
link, err := LoadPinnedRawLink(fileName)
if err != nil {
return nil, err
}
return &Iter{link}, err
}
// Iter represents an attached bpf_iter.
type Iter struct {
link *RawLink
}
var _ Link = (*Iter)(nil)
func (it *Iter) isLink() {}
// FD returns the underlying file descriptor.
func (it *Iter) FD() int {
return it.link.FD()
}
// Close implements Link.
func (it *Iter) Close() error {
return it.link.Close()
}
// Pin implements Link.
func (it *Iter) Pin(fileName string) error {
return it.link.Pin(fileName)
}
// Update implements Link.
func (it *Iter) Update(new *ebpf.Program) error {
return it.link.Update(new)
}
// Open creates a new instance of the iterator.
//
// Reading from the returned reader triggers the BPF program.
func (it *Iter) Open() (io.ReadCloser, error) {
linkFd, err := it.link.fd.Value()
if err != nil {
return nil, err
}
attr := &bpfIterCreateAttr{
linkFd: linkFd,
}
fd, err := bpfIterCreate(attr)
if err != nil {
return nil, fmt.Errorf("can't create iterator: %w", err)
}
return fd.File("bpf_iter"), nil
}
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