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allow to pin kprobe and kprobe_multi links #1496

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merged 1 commit into from
Jul 1, 2024
Merged

allow to pin kprobe and kprobe_multi links #1496

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8 changes: 0 additions & 8 deletions link/kprobe_multi.go
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Original file line number Diff line number Diff line change
Expand Up @@ -130,14 +130,6 @@ func (kml *kprobeMultiLink) Update(prog *ebpf.Program) error {
return fmt.Errorf("update kprobe_multi: %w", ErrNotSupported)
}

func (kml *kprobeMultiLink) Pin(string) error {
return fmt.Errorf("pin kprobe_multi: %w", ErrNotSupported)
}

func (kml *kprobeMultiLink) Unpin() error {
return fmt.Errorf("unpin kprobe_multi: %w", ErrNotSupported)
}

func (kml *kprobeMultiLink) Info() (*Info, error) {
var info sys.KprobeMultiLinkInfo
if err := sys.ObjInfo(kml.fd, &info); err != nil {
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2 changes: 1 addition & 1 deletion link/link.go
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Original file line number Diff line number Diff line change
Expand Up @@ -119,7 +119,7 @@ func wrapRawLink(raw *RawLink) (_ Link, err error) {
case UprobeMultiType:
return &uprobeMultiLink{*raw}, nil
case PerfEventType:
return nil, fmt.Errorf("recovering perf event fd: %w", ErrNotSupported)
return &perfEventLink{*raw, nil}, nil
case TCXType:
return &tcxLink{*raw}, nil
case NetfilterType:
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29 changes: 10 additions & 19 deletions link/perf_event.go
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Expand Up @@ -99,30 +99,16 @@ type perfEventLink struct {

func (pl *perfEventLink) isLink() {}

// Pinning requires the underlying perf event FD to stay open.
//
// | PerfEvent FD | BpfLink FD | Works |
// |--------------|------------|-------|
// | Open | Open | Yes |
// | Closed | Open | No |
// | Open | Closed | No (Pin() -> EINVAL) |
// | Closed | Closed | No (Pin() -> EINVAL) |
//
// There is currently no pretty way to recover the perf event FD
// when loading a pinned link, so leave as not supported for now.
func (pl *perfEventLink) Pin(string) error {
return fmt.Errorf("perf event link pin: %w", ErrNotSupported)
}

func (pl *perfEventLink) Unpin() error {
return fmt.Errorf("perf event link unpin: %w", ErrNotSupported)
}

func (pl *perfEventLink) Close() error {
if err := pl.fd.Close(); err != nil {
return fmt.Errorf("perf link close: %w", err)
}

// when created from pinned link
if pl.pe == nil {
return nil
}

if err := pl.pe.Close(); err != nil {
return fmt.Errorf("perf event close: %w", err)
}
Expand All @@ -136,6 +122,11 @@ func (pl *perfEventLink) Update(prog *ebpf.Program) error {
var _ PerfEvent = (*perfEventLink)(nil)

func (pl *perfEventLink) PerfEvent() (*os.File, error) {
// when created from pinned link
if pl.pe == nil {
return nil, ErrNotSupported
}

fd, err := pl.pe.fd.Dup()
if err != nil {
return nil, err
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