bpf2go: Generate constant names for maps, programs, and variables

Signed-off-by: Matthías Ásgeir Jónsson <[email protected]>

Author: mattijons

cmd/bpf2go/gen/output.tpl

@@ -22,6 +22,34 @@ import (
 {{ end }}
 {{- end }}
 
+{{- if or .Maps (or .Variables .Programs) }}
+// Constant names for all maps, variables, and programs as defined in the ELF file.
+//
+// They can be passed to ebpf.CollectionSpec and ebpf.Collection map fields.
+const (
+{{- if .Maps }}
+	// {{ .Name }} map names.
+{{- range $name, $id := .Maps }}
+	{{ $.Name }}MapName{{ $id }} = "{{ $name }}"
+{{- end }}
+{{- end }}
+
+{{- if .Variables }}
+	// {{ .Name }} variable names.
+{{- range $name, $id := .Variables }}
+	{{ $.Name }}VariableName{{ $id }} = "{{ $name }}"
+{{- end }}
+{{- end }}
+
+{{- if .Programs }}
+	// {{ .Name }} program names.
+{{- range $name, $id := .Programs }}
+	{{ $.Name }}ProgramName{{ $id }} = "{{ $name }}"
+{{- end }}
+{{- end }}
+)
+{{- end }}
+
 // {{ .Name.Load }} returns the embedded CollectionSpec for {{ .Name }}.
 func {{ .Name.Load }}() (*ebpf.CollectionSpec, error) {
 	reader := bytes.NewReader({{ .Name.Bytes }})

cmd/bpf2go/gen/output_test.go

@@ -95,7 +95,7 @@ func TestCustomIdentifier(t *testing.T) {
 	qt.Assert(t, qt.StringContains(buf.String(), "DO_THING"))
 }
 
-func TestObjects(t *testing.T) {
+func TestObjectsAndConstants(t *testing.T) {
 	var buf bytes.Buffer
 	args := GenerateArgs{
 		Package:   "foo",
@@ -117,6 +117,10 @@ func TestObjects(t *testing.T) {
 	qt.Assert(t, qt.StringContains(str, "Map1 *ebpf.Map `ebpf:\"map1\"`"))
 	qt.Assert(t, qt.StringContains(str, "Var1 *ebpf.Variable `ebpf:\"var_1\"`"))
 	qt.Assert(t, qt.StringContains(str, "ProgFoo1 *ebpf.Program `ebpf:\"prog_foo_1\"`"))
+
+	qt.Assert(t, qt.StringContains(str, "barMapNameMap1 = \"map1\""))
+	qt.Assert(t, qt.StringContains(str, "barVariableNameVar1 = \"var_1\""))
+	qt.Assert(t, qt.StringContains(str, "barProgramNameProgFoo1 = \"prog_foo_1\""))
 }
 
 func TestGenerateStructTypes(t *testing.T) {