func prepareMountOptions()

in pkg/csi_mounter/csi_mounter.go [282:342]
52 lines of code
9 McCabe index (conditional complexity)

func prepareMountOptions(options []string) ([]string, []string, map[string]int64, error) {
	allowedOptions := map[string]bool{
		"exec":    true,
		"noexec":  true,
		"atime":   true,
		"noatime": true,
		"sync":    true,
		"async":   true,
		"dirsync": true,
	}

	csiMountOptions := []string{
		"nodev",
		"nosuid",
		"allow_other",
		"default_permissions",
		"rootmode=40000",
		fmt.Sprintf("user_id=%d", os.Getuid()),
		fmt.Sprintf("group_id=%d", os.Getgid()),
	}

	// users may pass options that should be used by Linux mount(8),
	// filter out these options and not pass to the sidecar mounter.
	validMountOptions := []string{"rw", "ro"}
	optionSet := sets.NewString(options...)
	for _, o := range validMountOptions {
		if optionSet.Has(o) {
			csiMountOptions = append(csiMountOptions, o)
			optionSet.Delete(o)
		}
	}

	sysfsBDI := make(map[string]int64)
	for _, o := range optionSet.List() {
		if strings.HasPrefix(o, "o=") {
			v := o[2:]
			if allowedOptions[v] {
				csiMountOptions = append(csiMountOptions, v)
			} else {
				klog.Warningf("got invalid mount option %q. Will discard invalid options and continue to mount.", v)
			}
			optionSet.Delete(o)
		}

		if readAheadKB := readAheadKBMountFlagRegex.FindStringSubmatch(o); len(readAheadKB) == 2 {
			// There is only one matching pattern in readAheadKBMountFlagRegex
			// If found, it will be at index 1
			readAheadKBInt, err := strconv.ParseInt(readAheadKB[1], 10, 0)
			if err != nil {
				return nil, nil, nil, fmt.Errorf("invalid read_ahead_kb mount flag %q: %w", o, err)
			}
			if readAheadKBInt < 0 {
				return nil, nil, nil, fmt.Errorf("invalid negative value for read_ahead_kb mount flag: %q", o)
			}
			sysfsBDI[readAheadKBMountFlag] = readAheadKBInt
			optionSet.Delete(o)
		}
	}

	return csiMountOptions, optionSet.List(), sysfsBDI, nil
}