Pr/olsajiri/tailcalls

.github/workflows/checkpatch.yaml

@@ -19,4 +19,4 @@ jobs:
  - name: Run checkpatch.pl
  uses: docker://quay.io/cilium/cilium-checkpatch:2f0f4f512e795d5668ea4e7ef0ba85abc75eb225@sha256:f307bf0315954e8b8c31edc1864d949bf211b0c6522346359317d757b5a6cea0
  with:
- args: "-- --ignore PREFER_DEFINED_ATTRIBUTE_MACRO,C99_COMMENTS,OPEN_ENDED_LINE,PREFER_KERNEL_TYPES,REPEATED_WORD,SPDX_LICENSE_TAG,LONG_LINE,LONG_LINE_STRING,LONG_LINE_COMMENT,TRACE_PRINTK"
+ args: "-- --ignore PREFER_DEFINED_ATTRIBUTE_MACRO,C99_COMMENTS,OPEN_ENDED_LINE,PREFER_KERNEL_TYPES,REPEATED_WORD,SPDX_LICENSE_TAG,LONG_LINE,LONG_LINE_STRING,LONG_LINE_COMMENT,TRACE_PRINTK,AVOID_EXTERNS"

go.mod

@@ -9,7 +9,7 @@ require (
  github.com/alecthomas/kong v1.2.1
  github.com/bombsimon/logrusr/v4 v4.1.0
  github.com/cilium/cilium v1.17.0-pre.1
- github.com/cilium/ebpf v0.16.0
+ github.com/cilium/ebpf v0.16.1-0.20241017091859-59f2044b26b5
  github.com/cilium/little-vm-helper v0.0.19
  github.com/cilium/lumberjack/v2 v2.3.0
  github.com/cilium/tetragon/api v0.0.0-00010101000000-000000000000

go.sum

@@ -38,8 +38,8 @@ github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UF
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/cilium/cilium v1.17.0-pre.1 h1:HIJgJ8mtGrz6fgRI6YA/TPAsx2s06rmJTvmVe8RiilA=
 github.com/cilium/cilium v1.17.0-pre.1/go.mod h1:OM+QqlLdnaaQiGA9/OTTeVDBLyZYtwVDIbcTMMAm1gU=
-github.com/cilium/ebpf v0.16.0 h1:+BiEnHL6Z7lXnlGUsXQPPAE7+kenAd4ES8MQ5min0Ok=
-github.com/cilium/ebpf v0.16.0/go.mod h1:L7u2Blt2jMM/vLAVgjxluxtBKlz3/GWjB0dMOEngfwE=
+github.com/cilium/ebpf v0.16.1-0.20241017091859-59f2044b26b5 h1:09rId+70PyTuXqz7E6k5bLxFj7yqYKHfxRAye+i5VAU=
+github.com/cilium/ebpf v0.16.1-0.20241017091859-59f2044b26b5/go.mod h1:g+Zxp5bVKYJy9/njLFYE+mNTcw1P8TnE59/2Qq2Pr3I=
 github.com/cilium/hive v0.0.0-20240926131619-aa37668760f2 h1:xZn7yvMbK1+Au6D/YLKEMdcEsyMt6Qu7CUv+yQHGqv0=
 github.com/cilium/hive v0.0.0-20240926131619-aa37668760f2/go.mod h1:6tW1eCwSq8Wz8IVtpZE0MemoCWSrEOUa8aLKotmBRCo=
 github.com/cilium/little-vm-helper v0.0.19 h1:eJeJM/03MGLrLUXXTBDZo2JoX5cIbm5+9iWjoHgpy/M=

pkg/sensors/load.go

@@ -352,6 +352,10 @@ func (s *Sensor) loadMap(bpfDir string, m *program.Map) error {
  m.SetMaxEntries(int(max))
  }
 
+ // Disable content loading at this point, we just care about the map,
+ // the content will be loaded when the whole object gets loaded.
+ mapSpec.Contents = nil
+
  if err := m.LoadOrCreatePinnedMap(pinPath, mapSpec); err != nil {
  return fmt.Errorf("failed to load map '%s' for sensor '%s': %w", m.Name, s.Name, err)
  }

pkg/sensors/program/loader.go

@@ -734,6 +734,42 @@ func installTailCalls(bpfDir string, spec *ebpf.CollectionSpec, coll *ebpf.Colle
  return nil
 }
 
+// MissingConstantsError is returned by [rewriteConstants].
+type MissingConstantsError struct {
+ // The constants missing from .rodata.
+ Constants []string
+}
+
+func (m *MissingConstantsError) Error() string {
+ return fmt.Sprintf("some constants are missing from .rodata: %s", strings.Join(m.Constants, ", "))
+}
+
+func rewriteConstants(spec *ebpf.CollectionSpec, consts map[string]interface{}) error {
+ var missing []string
+
+ for n, c := range consts {
+ v, ok := spec.Variables[n]
+ if !ok {
+ missing = append(missing, n)
+ continue
+ }
+
+ if !v.Constant() {
+ return fmt.Errorf("variable %s is not a constant", n)
+ }
+
+ if err := v.Set(c); err != nil {
+ return fmt.Errorf("rewriting constant %s: %w", n, err)
+ }
+ }
+
+ if len(missing) != 0 {
+ return fmt.Errorf("rewrite constants: %w", &MissingConstantsError{Constants: missing})
+ }
+
+ return nil
+}
+
 func doLoadProgram(
  bpfDir string,
  load *Program,
@@ -756,7 +792,7 @@ func doLoadProgram(
  }
 
  if load.RewriteConstants != nil {
- if err := spec.RewriteConstants(load.RewriteConstants); err != nil {
+ if err := rewriteConstants(spec, load.RewriteConstants); err != nil {
  return nil, fmt.Errorf("rewritting constants in spec failed: %w", err)
  }
  }