whatcanGOwrong

go/pkg/mod/github.com/cilium/ebpf@v0.11.0/link/tracepoint_test.go

@@ -0,0 +1,96 @@
+package link
+
+import (
+	"errors"
+	"os"
+	"testing"
+
+	"github.com/cilium/ebpf"
+	"github.com/cilium/ebpf/internal/testutils"
+	"github.com/cilium/ebpf/internal/unix"
+
+	qt "github.com/frankban/quicktest"
+)
+
+func TestTracepoint(t *testing.T) {
+	// Requires at least 4.7 (98b5c2c65c29 "perf, bpf: allow bpf programs attach to tracepoints")
+	testutils.SkipOnOldKernel(t, "4.7", "tracepoint support")
+
+	prog := mustLoadProgram(t, ebpf.TracePoint, 0, "")
+
+	// printk is guaranteed to be present.
+	// Kernels before 4.14 don't support attaching to syscall tracepoints.
+	tp, err := Tracepoint("printk", "console", prog, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if err := tp.Close(); err != nil {
+		t.Error("closing tracepoint:", err)
+	}
+}
+
+func TestTracepointMissing(t *testing.T) {
+	// Requires at least 4.7 (98b5c2c65c29 "perf, bpf: allow bpf programs attach to tracepoints")
+	testutils.SkipOnOldKernel(t, "4.7", "tracepoint support")
+
+	prog := mustLoadProgram(t, ebpf.TracePoint, 0, "")
+
+	_, err := Tracepoint("missing", "foobazbar", prog, nil)
+	if !errors.Is(err, os.ErrNotExist) {
+		t.Error("Expected os.ErrNotExist, got", err)
+	}
+}
+
+func TestTracepointErrors(t *testing.T) {
+	c := qt.New(t)
+
+	// Invalid Tracepoint incantations.
+	_, err := Tracepoint("", "", nil, nil) // empty names
+	c.Assert(errors.Is(err, errInvalidInput), qt.IsTrue)
+
+	_, err = Tracepoint("_", "_", nil, nil) // empty prog
+	c.Assert(errors.Is(err, errInvalidInput), qt.IsTrue)
+
+	_, err = Tracepoint(".", "+", &ebpf.Program{}, nil) // illegal chars in group/name
+	c.Assert(errors.Is(err, errInvalidInput), qt.IsTrue)
+
+	_, err = Tracepoint("foo", "bar", &ebpf.Program{}, nil) // wrong prog type
+	c.Assert(errors.Is(err, errInvalidInput), qt.IsTrue)
+}
+
+func TestTracepointProgramCall(t *testing.T) {
+	// Kernels before 4.14 don't support attaching to syscall tracepoints.
+	testutils.SkipOnOldKernel(t, "4.14", "syscalls tracepoint support")
+
+	m, p := newUpdaterMapProg(t, ebpf.TracePoint, 0)
+
+	// Open Tracepoint at /sys/kernel/tracing/events/syscalls/sys_enter_getpid
+	// and attach it to the ebpf program created above.
+	tp, err := Tracepoint("syscalls", "sys_enter_getpid", p, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Trigger ebpf program call.
+	unix.Getpid()
+
+	// Assert that the value at index 0 has been updated to 1.
+	assertMapValue(t, m, 0, 1)
+
+	// Detach the Tracepoint.
+	if err := tp.Close(); err != nil {
+		t.Fatal(err)
+	}
+
+	// Reset map value to 0 at index 0.
+	if err := m.Update(uint32(0), uint32(0), ebpf.UpdateExist); err != nil {
+		t.Fatal(err)
+	}
+
+	// Retrigger the ebpf program call.
+	unix.Getpid()
+
+	// Assert that this time the value has not been updated.
+	assertMapValue(t, m, 0, 0)
+}