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|
// +build linux,cgo
package devmapper
import (
"bytes"
"fmt"
"os"
"path/filepath"
"golang.org/x/sys/unix"
)
// FIXME: this is copy-pasted from the aufs driver.
// It should be moved into the core.
// Mounted returns true if a mount point exists.
func Mounted(mountpoint string) (bool, error) {
var mntpointSt unix.Stat_t
if err := unix.Stat(mountpoint, &mntpointSt); err != nil {
if os.IsNotExist(err) {
return false, nil
}
return false, err
}
var parentSt unix.Stat_t
if err := unix.Stat(filepath.Join(mountpoint, ".."), &parentSt); err != nil {
return false, err
}
return mntpointSt.Dev != parentSt.Dev, nil
}
type probeData struct {
fsName string
magic string
offset uint64
}
// ProbeFsType returns the filesystem name for the given device id.
func ProbeFsType(device string) (string, error) {
probes := []probeData{
{"btrfs", "_BHRfS_M", 0x10040},
{"ext4", "\123\357", 0x438},
{"xfs", "XFSB", 0},
}
maxLen := uint64(0)
for _, p := range probes {
l := p.offset + uint64(len(p.magic))
if l > maxLen {
maxLen = l
}
}
file, err := os.Open(device)
if err != nil {
return "", err
}
defer file.Close()
buffer := make([]byte, maxLen)
l, err := file.Read(buffer)
if err != nil {
return "", err
}
if uint64(l) != maxLen {
return "", fmt.Errorf("devmapper: unable to detect filesystem type of %s, short read", device)
}
for _, p := range probes {
if bytes.Equal([]byte(p.magic), buffer[p.offset:p.offset+uint64(len(p.magic))]) {
return p.fsName, nil
}
}
return "", fmt.Errorf("devmapper: Unknown filesystem type on %s", device)
}
func joinMountOptions(a, b string) string {
if a == "" {
return b
}
if b == "" {
return a
}
return a + "," + b
}
|
