internal: embed BPF object into ior binary

5 files changed, 41 insertions, 16 deletions

diff --git a/integrationtests/README.md b/integrationtests/README.md
index 99a3fc0..be65499 100644
--- a/integrationtests/README.md
+++ b/integrationtests/README.md
@@ -6,9 +6,12 @@ harness asserts the captured `.ior.zst` output matches expectations.
 
 ## Prerequisites
 
-- Built `ior` binary and `ior.bpf.o` (`mage all`)
+- Built `ior` binary (`mage all`)
 - Root privileges or `CAP_BPF` (required for BPF tracepoint attachment)
 
+The binary embeds its default BPF object. Set `IOR_BPF_OBJECT=/path/to/ior.bpf.o`
+only when you explicitly want to override the embedded object during testing.
+
 ## Running
 
 ```bash
diff --git a/integrationtests/cleanup_test.go b/integrationtests/cleanup_test.go
index 18a0531..316c1b1 100644
--- a/integrationtests/cleanup_test.go
+++ b/integrationtests/cleanup_test.go
@@ -80,8 +80,7 @@ func TestCleanupOutputDirContainsOnlyExpectedFiles(t *testing.T) {
 	for _, e := range entries {
 		name := e.Name()
 		validSuffix := strings.HasSuffix(name, ".ior.zst") ||
-			strings.HasSuffix(name, ".svg") ||
-			name == "ior.bpf.o" // symlink created by startIor
+			strings.HasSuffix(name, ".svg")
 		if !validSuffix {
 			t.Errorf("unexpected file in output dir: %s", name)
 		}
@@ -172,11 +171,8 @@ func TestCleanupOutputDirEmptyAfterIorFailure(t *testing.T) {
 		t.Fatalf("read output dir: %v", err)
 	}
 
-	// Only the BPF symlink should exist; ior produced no output.
-	for _, e := range entries {
-		if e.Name() != "ior.bpf.o" {
-			t.Errorf("unexpected file in output dir after ior failure: %s", e.Name())
-		}
+	if len(entries) != 0 {
+		t.Fatalf("expected empty output dir after ior failure, found %d entries", len(entries))
 	}
 }
 
diff --git a/integrationtests/harness.go b/integrationtests/harness.go
index 17ae994..e3ee900 100644
--- a/integrationtests/harness.go
+++ b/integrationtests/harness.go
@@ -15,6 +15,7 @@ import (
 const (
 	workloadStartupTimeout = 5 * time.Second
 	iorShutdownGrace       = 30 * time.Second
+	bpfObjectOverrideEnv   = "IOR_BPF_OBJECT"
 )
 
 // TestHarness orchestrates integration tests by starting an ior trace
@@ -22,7 +23,7 @@ const (
 type TestHarness struct {
 	IorBinary      string // path to built ior binary
 	WorkloadBinary string // path to built ioworkload binary
-	BpfObject      string // path to ior.bpf.o
+	BpfObject      string // optional path to external BPF object override
 	OutputDir      string // temp dir for .ior.zst output
 }
 
@@ -120,11 +121,6 @@ func (h *TestHarness) startWorkload(scenario string) (*exec.Cmd, int, error) {
 }
 
 func (h *TestHarness) startIor(pid int, scenario string, duration int, extraArgs []string) (*exec.Cmd, error) {
-	bpfLink := filepath.Join(h.OutputDir, "ior.bpf.o")
-	if err := os.Symlink(h.BpfObject, bpfLink); err != nil {
-		return nil, fmt.Errorf("symlink bpf object: %w", err)
-	}
-
 	args := []string{
 		"-pid", strconv.Itoa(pid),
 		"-flamegraph",
@@ -136,6 +132,9 @@ func (h *TestHarness) startIor(pid int, scenario string, duration int, extraArgs
 	cmd.Dir = h.OutputDir
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
+	if h.BpfObject != "" {
+		cmd.Env = append(os.Environ(), bpfObjectOverrideEnv+"="+h.BpfObject)
+	}
 
 	if err := cmd.Start(); err != nil {
 		return nil, fmt.Errorf("start ior: %w", err)
diff --git a/integrationtests/harness_test.go b/integrationtests/harness_test.go
index 6e076ad..27a122c 100644
--- a/integrationtests/harness_test.go
+++ b/integrationtests/harness_test.go
@@ -178,3 +178,32 @@ func TestIorStartFailureCleansUpWorkload(t *testing.T) {
 		}
 	}
 }
+
+func TestStartIorPassesBPFObjectOverrideEnv(t *testing.T) {
+	tmpDir := t.TempDir()
+	outputDir := t.TempDir()
+	overridePath := filepath.Join(tmpDir, "fake.bpf.o")
+	iorBin := writeScript(t, tmpDir, "ior", `printf '%s' "$IOR_BPF_OBJECT" > "$PWD/override.txt"`)
+
+	h := TestHarness{
+		IorBinary: iorBin,
+		BpfObject: overridePath,
+		OutputDir: outputDir,
+	}
+
+	cmd, err := h.startIor(1234, "test", 5, nil)
+	if err != nil {
+		t.Fatalf("startIor returned error: %v", err)
+	}
+	if err := cmd.Wait(); err != nil {
+		t.Fatalf("wait for fake ior: %v", err)
+	}
+
+	data, err := os.ReadFile(filepath.Join(outputDir, "override.txt"))
+	if err != nil {
+		t.Fatalf("read override marker: %v", err)
+	}
+	if got, want := string(data), overridePath; got != want {
+		t.Fatalf("IOR_BPF_OBJECT = %q, want %q", got, want)
+	}
+}
diff --git a/integrationtests/helpers_test.go b/integrationtests/helpers_test.go
index feb7a55..6ef7ba7 100644
--- a/integrationtests/helpers_test.go
+++ b/integrationtests/helpers_test.go
@@ -9,7 +9,6 @@ import (
 const (
 	iorBinaryDefault      = "../ior"
 	workloadBinaryDefault = "../ioworkload"
-	bpfObjectDefault      = "../ior.bpf.o"
 	defaultDuration       = 10
 	parallelEnvVar        = "IOR_INTEGRATION_PARALLEL"
 )
@@ -23,7 +22,6 @@ func newTestHarness(t *testing.T) TestHarness {
 	return TestHarness{
 		IorBinary:      absPath(t, iorBinaryDefault),
 		WorkloadBinary: absPath(t, workloadBinaryDefault),
-		BpfObject:      absPath(t, bpfObjectDefault),
 		OutputDir:      t.TempDir(),
 	}
 }