1// +build darwin dragonfly freebsd linux netbsd openbsd solaris
2
3package fingerprint
4
5import (
6	"fmt"
7	"os/exec"
8	"path/filepath"
9	"runtime"
10	"strconv"
11	"strings"
12)
13
14// diskFree inspects the filesystem for path and returns the volume name and
15// the total and free bytes available on the file system.
16func (f *StorageFingerprint) diskFree(path string) (volume string, total, free uint64, err error) {
17	absPath, err := filepath.Abs(path)
18	if err != nil {
19		return "", 0, 0, fmt.Errorf("failed to determine absolute path for %s", path)
20	}
21
22	// Use -k to standardize the output values between darwin and linux
23	var dfArgs string
24	if runtime.GOOS == "linux" {
25		// df on linux needs the -P option to prevent linebreaks on long filesystem paths
26		dfArgs = "-kP"
27	} else {
28		dfArgs = "-k"
29	}
30
31	mountOutput, err := exec.Command("df", dfArgs, absPath).Output()
32	if err != nil {
33		return "", 0, 0, fmt.Errorf("failed to determine mount point for %s", absPath)
34	}
35	// Output looks something like:
36	//	Filesystem 1024-blocks      Used Available Capacity   iused    ifree %iused  Mounted on
37	//	/dev/disk1   487385240 423722532  63406708    87% 105994631 15851677   87%   /
38	//	[0] volume [1] capacity [2] SKIP  [3] free
39	lines := strings.Split(string(mountOutput), "\n")
40	if len(lines) < 2 {
41		return "", 0, 0, fmt.Errorf("failed to parse `df` output; expected at least 2 lines")
42	}
43	fields := strings.Fields(lines[1])
44	if len(fields) < 4 {
45		return "", 0, 0, fmt.Errorf("failed to parse `df` output; expected at least 4 columns")
46	}
47	volume = fields[0]
48
49	total, err = strconv.ParseUint(fields[1], 10, 64)
50	if err != nil {
51		return "", 0, 0, fmt.Errorf("failed to parse storage.bytestotal size in kilobytes")
52	}
53	// convert to bytes
54	total *= 1024
55
56	free, err = strconv.ParseUint(fields[3], 10, 64)
57	if err != nil {
58		return "", 0, 0, fmt.Errorf("failed to parse storage.bytesfree size in kilobytes")
59	}
60	// convert to bytes
61	free *= 1024
62
63	return volume, total, free, nil
64}
65