105 lines
2.8 KiB
Go
105 lines
2.8 KiB
Go
package mount
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import (
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"fmt"
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"os"
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"path/filepath"
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"syscall"
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"github.com/docker/docker/pkg/symlink"
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"github.com/docker/libcontainer/label"
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)
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type Mount struct {
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Type string `json:"type,omitempty"`
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Source string `json:"source,omitempty"` // Source path, in the host namespace
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Destination string `json:"destination,omitempty"` // Destination path, in the container
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Writable bool `json:"writable,omitempty"`
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Relabel string `json:"relabel,omitempty"` // Relabel source if set, "z" indicates shared, "Z" indicates unshared
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Private bool `json:"private,omitempty"`
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}
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func (m *Mount) Mount(rootfs, mountLabel string) error {
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switch m.Type {
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case "bind":
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return m.bindMount(rootfs, mountLabel)
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case "tmpfs":
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return m.tmpfsMount(rootfs, mountLabel)
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default:
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return fmt.Errorf("unsupported mount type %s for %s", m.Type, m.Destination)
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}
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}
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func (m *Mount) bindMount(rootfs, mountLabel string) error {
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var (
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flags = syscall.MS_BIND | syscall.MS_REC
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dest = filepath.Join(rootfs, m.Destination)
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)
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if !m.Writable {
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flags = flags | syscall.MS_RDONLY
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}
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stat, err := os.Stat(m.Source)
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if err != nil {
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return err
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}
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// FIXME: (crosbymichael) This does not belong here and should be done a layer above
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dest, err = symlink.FollowSymlinkInScope(dest, rootfs)
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if err != nil {
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return err
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}
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if err := createIfNotExists(dest, stat.IsDir()); err != nil {
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return fmt.Errorf("creating new bind mount target %s", err)
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}
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if err := syscall.Mount(m.Source, dest, "bind", uintptr(flags), ""); err != nil {
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return fmt.Errorf("mounting %s into %s %s", m.Source, dest, err)
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}
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if !m.Writable {
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if err := syscall.Mount(m.Source, dest, "bind", uintptr(flags|syscall.MS_REMOUNT), ""); err != nil {
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return fmt.Errorf("remounting %s into %s %s", m.Source, dest, err)
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}
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}
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if m.Relabel != "" {
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if err := label.Relabel(m.Source, mountLabel, m.Relabel); err != nil {
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return fmt.Errorf("relabeling %s to %s %s", m.Source, mountLabel, err)
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}
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}
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if m.Private {
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if err := syscall.Mount("", dest, "none", uintptr(syscall.MS_PRIVATE), ""); err != nil {
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return fmt.Errorf("mounting %s private %s", dest, err)
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}
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}
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return nil
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}
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func (m *Mount) tmpfsMount(rootfs, mountLabel string) error {
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var (
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err error
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l = label.FormatMountLabel("", mountLabel)
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dest = filepath.Join(rootfs, m.Destination)
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)
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// FIXME: (crosbymichael) This does not belong here and should be done a layer above
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if dest, err = symlink.FollowSymlinkInScope(dest, rootfs); err != nil {
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return err
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}
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if err := createIfNotExists(dest, true); err != nil {
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return fmt.Errorf("creating new tmpfs mount target %s", err)
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}
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if err := syscall.Mount("tmpfs", dest, "tmpfs", uintptr(defaultMountFlags), l); err != nil {
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return fmt.Errorf("%s mounting %s in tmpfs", err, dest)
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}
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return nil
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}
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