Function GetBuildID

internal/elfexec/elfexec.go:121–161

GetBuildID returns the GNU build-ID for an ELF binary. If no build-ID was found but the binary was read without error, it returns (nil, nil).

(f *elf.File)

// If no build-ID was found but the binary was read without error, it returns
// (nil, nil).
func GetBuildID(f *elf.File) ([]byte, error) {
	findBuildID := func(notes []elfNote) ([]byte, error) {
		var buildID []byte
		for _, note := range notes {
			if note.Name == "GNU" && note.Type == noteTypeGNUBuildID {
				if buildID == nil {
					buildID = note.Desc
				} else {
					return nil, fmt.Errorf("multiple build ids found, don't know which to use")
				}
			}
		}
		return buildID, nil
	}

	for _, p := range f.Progs {
		if p.Type != elf.PT_NOTE {
			continue
		}
		notes, err := parseNotes(p.Open(), int(p.Align), f.ByteOrder)
		if err != nil {
			return nil, err
		}
		if b, err := findBuildID(notes); b != nil || err != nil {
			return b, err
		}
	}
	for _, s := range f.Sections {
		if s.Type != elf.SHT_NOTE {
			continue
		}
		notes, err := parseNotes(s.Open(), int(s.Addralign), f.ByteOrder)
		if err != nil {
			return nil, err
		}
		if b, err := findBuildID(notes); b != nil || err != nil {
			return b, err
		}
	}
	return nil, nil
}

// kernelBase calculates the base for kernel mappings, which usually require
// special handling. For kernel mappings, tools (like perf) use the address of