mirror of https://github.com/containers/podman.git
124 lines
3.4 KiB
Go
124 lines
3.4 KiB
Go
package libpod
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import (
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"archive/tar"
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"io"
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"github.com/containers/libpod/libpod/layers"
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"github.com/containers/storage/pkg/archive"
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"github.com/pkg/errors"
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)
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var containerMounts = map[string]bool{
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"/dev": true,
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"/etc/hostname": true,
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"/etc/hosts": true,
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"/etc/resolv.conf": true,
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"/proc": true,
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"/run": true,
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"/run/.containerenv": true,
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"/run/secrets": true,
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"/sys": true,
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}
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// GetDiff returns the differences between the two images, layers, or containers
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func (r *Runtime) GetDiff(from, to string) ([]archive.Change, error) {
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toLayer, err := r.getLayerID(to)
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if err != nil {
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return nil, err
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}
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fromLayer := ""
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if from != "" {
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fromLayer, err = r.getLayerID(from)
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if err != nil {
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return nil, err
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}
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}
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var rchanges []archive.Change
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changes, err := r.store.Changes(fromLayer, toLayer)
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if err == nil {
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for _, c := range changes {
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if containerMounts[c.Path] {
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continue
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}
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rchanges = append(rchanges, c)
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}
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}
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return rchanges, err
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}
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// skipFileInTarAchive is an archive.TarModifierFunc function
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// which tells archive.ReplaceFileTarWrapper to skip files
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// from the tarstream
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func skipFileInTarAchive(path string, header *tar.Header, content io.Reader) (*tar.Header, []byte, error) {
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return nil, nil, nil
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}
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// GetDiffTarStream returns the differences between the two images, layers, or containers.
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// It is the same functionality as GetDiff() except that it returns a tarstream
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func (r *Runtime) GetDiffTarStream(from, to string) (io.ReadCloser, error) {
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toLayer, err := r.getLayerID(to)
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if err != nil {
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return nil, err
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}
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fromLayer := ""
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if from != "" {
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fromLayer, err = r.getLayerID(from)
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if err != nil {
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return nil, err
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}
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}
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rc, err := r.store.Diff(fromLayer, toLayer, nil)
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if err != nil {
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return nil, err
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}
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// Skip files in the tar archive which are listed
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// in containerMounts map. Just as in the GetDiff()
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// function from above
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filterMap := make(map[string]archive.TarModifierFunc)
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for key := range containerMounts {
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filterMap[key[1:]] = skipFileInTarAchive
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// In the tarstream directories always include a trailing '/'.
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// For simplicity this duplicates every entry from
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// containerMounts with a trailing '/', as containerMounts
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// does not use trailing '/' for directories.
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filterMap[key[1:]+"/"] = skipFileInTarAchive
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}
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filteredTarStream := archive.ReplaceFileTarWrapper(rc, filterMap)
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return filteredTarStream, nil
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}
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// ApplyDiffTarStream applies the changes stored in 'diff' to the layer 'to'
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func (r *Runtime) ApplyDiffTarStream(to string, diff io.Reader) error {
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toLayer, err := r.getLayerID(to)
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if err != nil {
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return err
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}
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_, err = r.store.ApplyDiff(toLayer, diff)
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return err
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}
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// GetLayerID gets a full layer id given a full or partial id
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// If the id matches a container or image, the id of the top layer is returned
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// If the id matches a layer, the top layer id is returned
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func (r *Runtime) getLayerID(id string) (string, error) {
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var toLayer string
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toImage, err := r.imageRuntime.NewFromLocal(id)
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if err != nil {
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toCtr, err := r.store.Container(id)
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if err != nil {
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toLayer, err = layers.FullID(r.store, id)
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if err != nil {
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return "", errors.Errorf("layer, image, or container %s does not exist", id)
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}
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} else {
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toLayer = toCtr.LayerID
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}
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} else {
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toLayer = toImage.TopLayer()
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}
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return toLayer, nil
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}
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