internal: embed BPF object into ior binary

3 files changed, 130 insertions, 2 deletions

diff --git a/internal/bpfembed.go b/internal/bpfembed.go
new file mode 100644
index 0000000..fce784c
--- /dev/null
+++ b/internal/bpfembed.go
@@ -0,0 +1,31 @@
+package internal
+
+import (
+	_ "embed"
+	"os"
+
+	bpf "github.com/aquasecurity/libbpfgo"
+)
+
+const (
+	bpfObjectOverrideEnv  = "IOR_BPF_OBJECT"
+	embeddedBPFObjectName = "ior.bpf.o"
+)
+
+//go:embed c/ior.bpf.o
+var embeddedBPFObject []byte
+
+var (
+	newBPFModuleFromFile   = bpf.NewModuleFromFile
+	newBPFModuleFromBuffer = bpf.NewModuleFromBuffer
+)
+
+func loadBPFModule() (*bpf.Module, string, error) {
+	if path := os.Getenv(bpfObjectOverrideEnv); path != "" {
+		module, err := newBPFModuleFromFile(path)
+		return module, "load module from override file", err
+	}
+
+	module, err := newBPFModuleFromBuffer(embeddedBPFObject, embeddedBPFObjectName)
+	return module, "load embedded module", err
+}
diff --git a/internal/ior.go b/internal/ior.go
index c14ab37..3f145a9 100644
--- a/internal/ior.go
+++ b/internal/ior.go
@@ -342,9 +342,9 @@ func setupBPFModuleError(stage string, err error) error {
 func setupBPFModule(parentCtx context.Context, cfg flags.Config) (*bpf.Module, *probemanager.Manager, func(), error) {
 	releaseBindings := func() {}
 
-	bpfModule, err := bpf.NewModuleFromFile("ior.bpf.o")
+	bpfModule, stage, err := loadBPFModule()
 	if err != nil {
-		return nil, nil, releaseBindings, setupBPFModuleError("load module from file", err)
+		return nil, nil, releaseBindings, setupBPFModuleError(stage, err)
 	}
 	if err := resizeBPFMaps(cfg, bpfModule); err != nil {
 		bpfModule.Close()
diff --git a/internal/ior_setup_test.go b/internal/ior_setup_test.go
index 9c8b1b3..9c804c7 100644
--- a/internal/ior_setup_test.go
+++ b/internal/ior_setup_test.go
@@ -1,8 +1,12 @@
 package internal
 
 import (
+	"bytes"
 	"errors"
+	"os"
 	"testing"
+
+	bpf "github.com/aquasecurity/libbpfgo"
 )
 
 func TestSetupBPFModuleErrorWrapsStage(t *testing.T) {
@@ -25,3 +29,96 @@ func TestSetupBPFModuleErrorNil(t *testing.T) {
 		t.Fatalf("expected nil error passthrough, got %v", err)
 	}
 }
+
+func TestLoadBPFModuleUsesEmbeddedObjectByDefault(t *testing.T) {
+	origFile := newBPFModuleFromFile
+	origBuffer := newBPFModuleFromBuffer
+	origOverride, hadOverride := os.LookupEnv(bpfObjectOverrideEnv)
+	t.Cleanup(func() {
+		newBPFModuleFromFile = origFile
+		newBPFModuleFromBuffer = origBuffer
+		if hadOverride {
+			os.Setenv(bpfObjectOverrideEnv, origOverride)
+			return
+		}
+		os.Unsetenv(bpfObjectOverrideEnv)
+	})
+	os.Unsetenv(bpfObjectOverrideEnv)
+
+	wantErr := errors.New("buffer load failed")
+	newBPFModuleFromFile = func(string) (*bpf.Module, error) {
+		t.Fatal("expected embedded loader, not file loader")
+		return nil, nil
+	}
+
+	var gotBytes []byte
+	var gotName string
+	newBPFModuleFromBuffer = func(data []byte, name string) (*bpf.Module, error) {
+		gotBytes = append([]byte(nil), data...)
+		gotName = name
+		return nil, wantErr
+	}
+
+	module, stage, err := loadBPFModule()
+	if module != nil {
+		t.Fatalf("expected nil module from stubbed loader, got %v", module)
+	}
+	if got, want := stage, "load embedded module"; got != want {
+		t.Fatalf("stage = %q, want %q", got, want)
+	}
+	if !errors.Is(err, wantErr) {
+		t.Fatalf("expected embedded loader error, got %v", err)
+	}
+	if !bytes.Equal(gotBytes, embeddedBPFObject) {
+		t.Fatalf("embedded loader received unexpected object bytes")
+	}
+	if got, want := gotName, embeddedBPFObjectName; got != want {
+		t.Fatalf("embedded loader name = %q, want %q", got, want)
+	}
+}
+
+func TestLoadBPFModuleUsesOverridePathWhenConfigured(t *testing.T) {
+	origFile := newBPFModuleFromFile
+	origBuffer := newBPFModuleFromBuffer
+	origOverride, hadOverride := os.LookupEnv(bpfObjectOverrideEnv)
+	t.Cleanup(func() {
+		newBPFModuleFromFile = origFile
+		newBPFModuleFromBuffer = origBuffer
+		if hadOverride {
+			os.Setenv(bpfObjectOverrideEnv, origOverride)
+			return
+		}
+		os.Unsetenv(bpfObjectOverrideEnv)
+	})
+
+	overridePath := "/tmp/custom-ior.bpf.o"
+	if err := os.Setenv(bpfObjectOverrideEnv, overridePath); err != nil {
+		t.Fatalf("set override env: %v", err)
+	}
+
+	wantErr := errors.New("file load failed")
+	newBPFModuleFromBuffer = func([]byte, string) (*bpf.Module, error) {
+		t.Fatal("expected file loader, not embedded loader")
+		return nil, nil
+	}
+
+	var gotPath string
+	newBPFModuleFromFile = func(path string) (*bpf.Module, error) {
+		gotPath = path
+		return nil, wantErr
+	}
+
+	module, stage, err := loadBPFModule()
+	if module != nil {
+		t.Fatalf("expected nil module from stubbed loader, got %v", module)
+	}
+	if got, want := stage, "load module from override file"; got != want {
+		t.Fatalf("stage = %q, want %q", got, want)
+	}
+	if !errors.Is(err, wantErr) {
+		t.Fatalf("expected override loader error, got %v", err)
+	}
+	if got, want := gotPath, overridePath; got != want {
+		t.Fatalf("override path = %q, want %q", got, want)
+	}
+}