34d5878185
- Add Target to mount.Mount. - Add UnmountMounts to unmount a list of mounts in reverse order. - Add UnmountRecursive to unmount deepest mount first for a given target, using moby/sys/mountinfo. Signed-off-by: Edgar Lee <edgarhinshunlee@gmail.com>
114 lines
3.1 KiB
Go
114 lines
3.1 KiB
Go
/*
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Copyright The containerd Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package mount
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import (
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"encoding/json"
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"fmt"
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"os"
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"path/filepath"
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"strings"
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"github.com/Microsoft/hcsshim"
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)
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// Mount to the provided target.
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func (m *Mount) mount(target string) error {
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if m.Type != "windows-layer" {
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return fmt.Errorf("invalid windows mount type: '%s'", m.Type)
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}
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home, layerID := filepath.Split(m.Source)
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parentLayerPaths, err := m.GetParentPaths()
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if err != nil {
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return err
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}
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var di = hcsshim.DriverInfo{
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HomeDir: home,
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}
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if err = hcsshim.ActivateLayer(di, layerID); err != nil {
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return fmt.Errorf("failed to activate layer %s: %w", m.Source, err)
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}
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if err = hcsshim.PrepareLayer(di, layerID, parentLayerPaths); err != nil {
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return fmt.Errorf("failed to prepare layer %s: %w", m.Source, err)
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}
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// We can link the layer mount path to the given target. It is an UNC path, and it needs
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// a trailing backslash.
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mountPath, err := hcsshim.GetLayerMountPath(di, layerID)
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if err != nil {
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return fmt.Errorf("failed to get layer mount path for %s: %w", m.Source, err)
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}
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mountPath = mountPath + `\`
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if err = os.Symlink(mountPath, target); err != nil {
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return fmt.Errorf("failed to link mount to target %s: %w", target, err)
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}
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return nil
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}
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// ParentLayerPathsFlag is the options flag used to represent the JSON encoded
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// list of parent layers required to use the layer
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const ParentLayerPathsFlag = "parentLayerPaths="
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// GetParentPaths of the mount
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func (m *Mount) GetParentPaths() ([]string, error) {
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var parentLayerPaths []string
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for _, option := range m.Options {
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if strings.HasPrefix(option, ParentLayerPathsFlag) {
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err := json.Unmarshal([]byte(option[len(ParentLayerPathsFlag):]), &parentLayerPaths)
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if err != nil {
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return nil, fmt.Errorf("failed to unmarshal parent layer paths from mount: %w", err)
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}
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}
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}
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return parentLayerPaths, nil
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}
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// Unmount the mount at the provided path
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func Unmount(mount string, flags int) error {
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var (
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home, layerID = filepath.Split(mount)
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di = hcsshim.DriverInfo{
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HomeDir: home,
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}
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)
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if err := hcsshim.UnprepareLayer(di, layerID); err != nil {
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return fmt.Errorf("failed to unprepare layer %s: %w", mount, err)
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}
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if err := hcsshim.DeactivateLayer(di, layerID); err != nil {
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return fmt.Errorf("failed to deactivate layer %s: %w", mount, err)
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}
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return nil
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}
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// UnmountAll unmounts from the provided path
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func UnmountAll(mount string, flags int) error {
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return Unmount(mount, flags)
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}
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// UnmountRecursive unmounts from the provided path
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func UnmountRecursive(mount string, flags int) error {
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return UnmountAll(mount, flags)
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}
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