| // +build linux |
| |
| package fs |
| |
| import ( |
| "errors" |
| "fmt" |
| "io/ioutil" |
| "path/filepath" |
| "strconv" |
| "strings" |
| ) |
| |
| var ( |
| ErrNotValidFormat = errors.New("line is not a valid key value format") |
| ) |
| |
| // Saturates negative values at zero and returns a uint64. |
| // Due to kernel bugs, some of the memory cgroup stats can be negative. |
| func parseUint(s string, base, bitSize int) (uint64, error) { |
| value, err := strconv.ParseUint(s, base, bitSize) |
| if err != nil { |
| intValue, intErr := strconv.ParseInt(s, base, bitSize) |
| // 1. Handle negative values greater than MinInt64 (and) |
| // 2. Handle negative values lesser than MinInt64 |
| if intErr == nil && intValue < 0 { |
| return 0, nil |
| } else if intErr != nil && intErr.(*strconv.NumError).Err == strconv.ErrRange && intValue < 0 { |
| return 0, nil |
| } |
| |
| return value, err |
| } |
| |
| return value, nil |
| } |
| |
| // Parses a cgroup param and returns as name, value |
| // i.e. "io_service_bytes 1234" will return as io_service_bytes, 1234 |
| func getCgroupParamKeyValue(t string) (string, uint64, error) { |
| parts := strings.Fields(t) |
| switch len(parts) { |
| case 2: |
| value, err := parseUint(parts[1], 10, 64) |
| if err != nil { |
| return "", 0, fmt.Errorf("unable to convert param value (%q) to uint64: %v", parts[1], err) |
| } |
| |
| return parts[0], value, nil |
| default: |
| return "", 0, ErrNotValidFormat |
| } |
| } |
| |
| // Gets a single uint64 value from the specified cgroup file. |
| func getCgroupParamUint(cgroupPath, cgroupFile string) (uint64, error) { |
| fileName := filepath.Join(cgroupPath, cgroupFile) |
| contents, err := ioutil.ReadFile(fileName) |
| if err != nil { |
| return 0, err |
| } |
| |
| res, err := parseUint(strings.TrimSpace(string(contents)), 10, 64) |
| if err != nil { |
| return res, fmt.Errorf("unable to parse %q as a uint from Cgroup file %q", string(contents), fileName) |
| } |
| return res, nil |
| } |
| |
| // Gets a string value from the specified cgroup file |
| func getCgroupParamString(cgroupPath, cgroupFile string) (string, error) { |
| contents, err := ioutil.ReadFile(filepath.Join(cgroupPath, cgroupFile)) |
| if err != nil { |
| return "", err |
| } |
| |
| return strings.TrimSpace(string(contents)), nil |
| } |