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