| package mount // import "github.com/docker/docker/pkg/mount" |
| |
| import ( |
| "sort" |
| "strconv" |
| "strings" |
| |
| "github.com/sirupsen/logrus" |
| ) |
| |
| // mountError records an error from mount or unmount operation |
| type mountError struct { |
| op string |
| source, target string |
| flags uintptr |
| data string |
| err error |
| } |
| |
| func (e *mountError) Error() string { |
| out := e.op + " " |
| |
| if e.source != "" { |
| out += e.source + ":" + e.target |
| } else { |
| out += e.target |
| } |
| |
| if e.flags != uintptr(0) { |
| out += ", flags: 0x" + strconv.FormatUint(uint64(e.flags), 16) |
| } |
| if e.data != "" { |
| out += ", data: " + e.data |
| } |
| |
| out += ": " + e.err.Error() |
| return out |
| } |
| |
| // Cause returns the underlying cause of the error |
| func (e *mountError) Cause() error { |
| return e.err |
| } |
| |
| // FilterFunc is a type defining a callback function |
| // to filter out unwanted entries. It takes a pointer |
| // to an Info struct (not fully populated, currently |
| // only Mountpoint is filled in), and returns two booleans: |
| // - skip: true if the entry should be skipped |
| // - stop: true if parsing should be stopped after the entry |
| type FilterFunc func(*Info) (skip, stop bool) |
| |
| // PrefixFilter discards all entries whose mount points |
| // do not start with a prefix specified |
| func PrefixFilter(prefix string) FilterFunc { |
| return func(m *Info) (bool, bool) { |
| skip := !strings.HasPrefix(m.Mountpoint, prefix) |
| return skip, false |
| } |
| } |
| |
| // SingleEntryFilter looks for a specific entry |
| func SingleEntryFilter(mp string) FilterFunc { |
| return func(m *Info) (bool, bool) { |
| if m.Mountpoint == mp { |
| return false, true // don't skip, stop now |
| } |
| return true, false // skip, keep going |
| } |
| } |
| |
| // ParentsFilter returns all entries whose mount points |
| // can be parents of a path specified, discarding others. |
| // For example, given `/var/lib/docker/something`, entries |
| // like `/var/lib/docker`, `/var` and `/` are returned. |
| func ParentsFilter(path string) FilterFunc { |
| return func(m *Info) (bool, bool) { |
| skip := !strings.HasPrefix(path, m.Mountpoint) |
| return skip, false |
| } |
| } |
| |
| // GetMounts retrieves a list of mounts for the current running process, |
| // with an optional filter applied (use nil for no filter). |
| func GetMounts(f FilterFunc) ([]*Info, error) { |
| return parseMountTable(f) |
| } |
| |
| // Mounted determines if a specified mountpoint has been mounted. |
| // On Linux it looks at /proc/self/mountinfo. |
| func Mounted(mountpoint string) (bool, error) { |
| entries, err := GetMounts(SingleEntryFilter(mountpoint)) |
| if err != nil { |
| return false, err |
| } |
| |
| return len(entries) > 0, nil |
| } |
| |
| // Mount will mount filesystem according to the specified configuration, on the |
| // condition that the target path is *not* already mounted. Options must be |
| // specified like the mount or fstab unix commands: "opt1=val1,opt2=val2". See |
| // flags.go for supported option flags. |
| func Mount(device, target, mType, options string) error { |
| flag, _ := parseOptions(options) |
| if flag&REMOUNT != REMOUNT { |
| if mounted, err := Mounted(target); err != nil || mounted { |
| return err |
| } |
| } |
| return ForceMount(device, target, mType, options) |
| } |
| |
| // ForceMount will mount a filesystem according to the specified configuration, |
| // *regardless* if the target path is not already mounted. Options must be |
| // specified like the mount or fstab unix commands: "opt1=val1,opt2=val2". See |
| // flags.go for supported option flags. |
| func ForceMount(device, target, mType, options string) error { |
| flag, data := parseOptions(options) |
| return mount(device, target, mType, uintptr(flag), data) |
| } |
| |
| // Unmount lazily unmounts a filesystem on supported platforms, otherwise |
| // does a normal unmount. |
| func Unmount(target string) error { |
| return unmount(target, mntDetach) |
| } |
| |
| // RecursiveUnmount unmounts the target and all mounts underneath, starting with |
| // the deepsest mount first. |
| func RecursiveUnmount(target string) error { |
| mounts, err := parseMountTable(PrefixFilter(target)) |
| if err != nil { |
| return err |
| } |
| |
| // Make the deepest mount be first |
| sort.Slice(mounts, func(i, j int) bool { |
| return len(mounts[i].Mountpoint) > len(mounts[j].Mountpoint) |
| }) |
| |
| for i, m := range mounts { |
| logrus.Debugf("Trying to unmount %s", m.Mountpoint) |
| err = unmount(m.Mountpoint, mntDetach) |
| if err != nil { |
| if i == len(mounts)-1 { // last mount |
| if mounted, e := Mounted(m.Mountpoint); e != nil || mounted { |
| return err |
| } |
| } else { |
| // This is some submount, we can ignore this error for now, the final unmount will fail if this is a real problem |
| logrus.WithError(err).Warnf("Failed to unmount submount %s", m.Mountpoint) |
| } |
| } |
| |
| logrus.Debugf("Unmounted %s", m.Mountpoint) |
| } |
| return nil |
| } |