Add pfelf support for go version detection

libpf/pfelf/file.go

@@ -21,13 +21,15 @@ package pfelf // import "go.opentelemetry.io/ebpf-profiler/libpf/pfelf"
 
 import (
 	"bytes"
+	"debug/buildinfo"
 	"debug/elf"
 	"errors"
 	"fmt"
 	"hash/crc32"
 	"io"
 	"os"
 	"path/filepath"
+	"runtime/debug"
 	"sort"
 	"syscall"
 	"unsafe"
@@ -119,6 +121,9 @@ type File struct {
 	debuglinkPath string
 	// Whether we have checked for a debuglink
 	debuglinkChecked bool
+
+	// Contains the Go build information if present
+	goBuildInfo *debug.BuildInfo
 }
 
 var _ libpf.SymbolFinder = &File{}
@@ -489,6 +494,26 @@ func (f *File) GetBuildID() (string, error) {
 	return getBuildIDFromNotes(data)
 }
 
+// GoVersion returns the Go version if present and empty string otherwise. This will delegate
+// to buildinfo.Read for any binaries where IsGolang is true which will scan the binary with
+// debug/elf. This will incur additional CPU/IO overhead but the libpf.readbufat buffer and
+// OS file buffers should ameliorate most of that.
+func (f *File) GoVersion() (string, error) {
+	if f.goBuildInfo != nil {
+		return f.goBuildInfo.GoVersion, nil
+	}
+	if !f.IsGolang() {
+		return "", nil
+	}
+	bi, err := buildinfo.Read(f.elfReader)
+	if err != nil {
+		return "", err
+	}
+	f.goBuildInfo = bi
+
+	return bi.GoVersion, nil
+}
+
 // DebuglinkFileName returns the debug file linked by .gnu_debuglink if any
 func (f *File) DebuglinkFileName(elfFilePath string, elfOpener ELFOpener) string {
 	if f.debuglinkChecked {

libpf/pfelf/file_test.go

@@ -4,7 +4,9 @@
 package pfelf
 
 import (
+	"go/version"
 	"os"
+	"runtime"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -78,3 +80,18 @@ func TestPFELFIsGolang(t *testing.T) {
 	testPFELFIsGolang(t, "testdata/go-binary", true)
 	testPFELFIsGolang(t, "testdata/without-debug-syms", false)
 }
+
+func TestGoVersion(t *testing.T) {
+	ef := getPFELF("testdata/go-binary", t)
+	defer ef.Close()
+
+	vers, err := ef.GoVersion()
+	require.NoError(t, err)
+	assert.GreaterOrEqual(t, version.Compare(vers, "go1.23.6"), 0)
+
+	testEF := getPFELF("/proc/self/exe", t)
+	defer testEF.Close()
+	testVersion, err := testEF.GoVersion()
+	require.NoError(t, err)
+	assert.Equal(t, runtime.Version(), testVersion)
+}

libpf/pfelf/testdata/Makefile

@@ -44,7 +44,6 @@ kernel-image: test.c
 ubuntu-kernel-image: test.c
 	$(CC) $< -s -o $@ -DLINUX_VERSION="\"Linux version 1.2.3 (Ubuntu 4.5.6)\\n\""
 
-# A fake go binary (with a .gopclntab section)
-go-binary: without-debug-syms
-	$(OBJCOPY) --add-section .gopclntab=/dev/null $< $@
+go-binary: gotest.go
+	go build -o go-binary -ldflags "-w -s" gotest.go
 

libpf/pfelf/testdata/gotest.go

@@ -0,0 +1,4 @@
+package main
+
+func main() {
+}