From bf92e21113c9b2d2ff4c18423ff3deb10a1ce29e Mon Sep 17 00:00:00 2001
From: Adrian Reber <areber@redhat.com>
Date: Thu, 25 Feb 2021 15:34:12 +0000
Subject: Move checkpoint/restore code to pkg/checkpoint/crutils
To be able to reuse common checkpoint/restore functions this commit
moves code to pkg/checkpoint/crutils.
This commit has not functional changes. It only moves code around.
[NO TESTS NEEDED] - only moving code around
Signed-off-by: Adrian Reber <areber@redhat.com>
---
pkg/checkpoint/crutils/checkpoint_restore_utils.go | 191 +++++++++++++++++++++
1 file changed, 191 insertions(+)
create mode 100644 pkg/checkpoint/crutils/checkpoint_restore_utils.go
(limited to 'pkg/checkpoint/crutils/checkpoint_restore_utils.go')
diff --git a/pkg/checkpoint/crutils/checkpoint_restore_utils.go b/pkg/checkpoint/crutils/checkpoint_restore_utils.go
new file mode 100644
index 000000000..53ff55865
--- /dev/null
+++ b/pkg/checkpoint/crutils/checkpoint_restore_utils.go
@@ -0,0 +1,191 @@
+package crutils
+
+import (
+ "io"
+ "os"
+ "os/exec"
+ "path/filepath"
+
+ metadata "github.com/checkpoint-restore/checkpointctl/lib"
+ "github.com/containers/storage/pkg/archive"
+ "github.com/opencontainers/selinux/go-selinux/label"
+ "github.com/pkg/errors"
+)
+
+// This file mainly exist to make the checkpoint/restore functions
+// available for other users. One possible candidate would be CRI-O.
+
+// CRImportCheckpointWithoutConfig imports the checkpoint archive (input)
+// into the directory destination without "config.dump" and "spec.dump"
+func CRImportCheckpointWithoutConfig(destination, input string) error {
+ archiveFile, err := os.Open(input)
+ if err != nil {
+ return errors.Wrapf(err, "Failed to open checkpoint archive %s for import", input)
+ }
+
+ defer archiveFile.Close()
+ options := &archive.TarOptions{
+ ExcludePatterns: []string{
+ // Import everything else besides the container config
+ metadata.ConfigDumpFile,
+ metadata.SpecDumpFile,
+ },
+ }
+ if err = archive.Untar(archiveFile, destination, options); err != nil {
+ return errors.Wrapf(err, "Unpacking of checkpoint archive %s failed", input)
+ }
+
+ return nil
+}
+
+// CRRemoveDeletedFiles loads the list of deleted files and if
+// it exists deletes all files listed.
+func CRRemoveDeletedFiles(id, baseDirectory, containerRootDirectory string) error {
+ deletedFiles, _, err := metadata.ReadContainerCheckpointDeletedFiles(baseDirectory)
+ if os.IsNotExist(errors.Unwrap(errors.Unwrap(err))) {
+ // No files to delete. Just return
+ return nil
+ }
+
+ if err != nil {
+ return errors.Wrapf(err, "failed to read deleted files file")
+ }
+
+ for _, deleteFile := range deletedFiles {
+ // Using RemoveAll as deletedFiles, which is generated from 'podman diff'
+ // lists completely deleted directories as a single entry: 'D /root'.
+ if err := os.RemoveAll(filepath.Join(containerRootDirectory, deleteFile)); err != nil {
+ return errors.Wrapf(err, "failed to delete files from container %s during restore", id)
+ }
+ }
+
+ return nil
+}
+
+// CRApplyRootFsDiffTar applies the tar archive found in baseDirectory with the
+// root file system changes on top of containerRootDirectory
+func CRApplyRootFsDiffTar(baseDirectory, containerRootDirectory string) error {
+ rootfsDiffPath := filepath.Join(baseDirectory, metadata.RootFsDiffTar)
+ if _, err := os.Stat(rootfsDiffPath); err != nil {
+ // Only do this if a rootfs-diff.tar actually exists
+ return nil
+ }
+
+ rootfsDiffFile, err := os.Open(rootfsDiffPath)
+ if err != nil {
+ return errors.Wrap(err, "failed to open root file-system diff file")
+ }
+ defer rootfsDiffFile.Close()
+
+ if err := archive.Untar(rootfsDiffFile, containerRootDirectory, nil); err != nil {
+ return errors.Wrapf(err, "failed to apply root file-system diff file %s", rootfsDiffPath)
+ }
+
+ return nil
+}
+
+// CRCreateRootFsDiffTar goes through the 'changes' and can create two files:
+// * metadata.RootFsDiffTar will contain all new and changed files
+// * metadata.DeletedFilesFile will contain a list of deleted files
+// With these two files it is possible to restore the container file system to the same
+// state it was during checkpointing.
+// Changes to directories (owner, mode) are not handled.
+func CRCreateRootFsDiffTar(changes *[]archive.Change, mountPoint, destination string) (includeFiles []string, err error) {
+ if len(*changes) == 0 {
+ return includeFiles, nil
+ }
+
+ var rootfsIncludeFiles []string
+ var deletedFiles []string
+
+ rootfsDiffPath := filepath.Join(destination, metadata.RootFsDiffTar)
+
+ for _, file := range *changes {
+ if file.Kind == archive.ChangeAdd {
+ rootfsIncludeFiles = append(rootfsIncludeFiles, file.Path)
+ continue
+ }
+ if file.Kind == archive.ChangeDelete {
+ deletedFiles = append(deletedFiles, file.Path)
+ continue
+ }
+ fileName, err := os.Stat(file.Path)
+ if err != nil {
+ continue
+ }
+ if !fileName.IsDir() && file.Kind == archive.ChangeModify {
+ rootfsIncludeFiles = append(rootfsIncludeFiles, file.Path)
+ continue
+ }
+ }
+
+ if len(rootfsIncludeFiles) > 0 {
+ rootfsTar, err := archive.TarWithOptions(mountPoint, &archive.TarOptions{
+ Compression: archive.Uncompressed,
+ IncludeSourceDir: true,
+ IncludeFiles: rootfsIncludeFiles,
+ })
+ if err != nil {
+ return includeFiles, errors.Wrapf(err, "error exporting root file-system diff to %q", rootfsDiffPath)
+ }
+ rootfsDiffFile, err := os.Create(rootfsDiffPath)
+ if err != nil {
+ return includeFiles, errors.Wrapf(err, "error creating root file-system diff file %q", rootfsDiffPath)
+ }
+ defer rootfsDiffFile.Close()
+ if _, err = io.Copy(rootfsDiffFile, rootfsTar); err != nil {
+ return includeFiles, err
+ }
+
+ includeFiles = append(includeFiles, metadata.RootFsDiffTar)
+ }
+
+ if len(deletedFiles) == 0 {
+ return includeFiles, nil
+ }
+
+ if _, err := metadata.WriteJSONFile(deletedFiles, destination, metadata.DeletedFilesFile); err != nil {
+ return includeFiles, nil
+ }
+
+ includeFiles = append(includeFiles, metadata.DeletedFilesFile)
+
+ return includeFiles, nil
+}
+
+// CRCreateFileWithLabel creates an empty file and sets the corresponding ('fileLabel')
+// SELinux label on the file.
+// This is necessary for CRIU log files because CRIU infects the processes in
+// the container with a 'parasite' and this will also try to write to the log files
+// from the context of the container processes.
+func CRCreateFileWithLabel(directory, fileName, fileLabel string) error {
+ logFileName := filepath.Join(directory, fileName)
+
+ logFile, err := os.OpenFile(logFileName, os.O_CREATE, 0o600)
+ if err != nil {
+ return errors.Wrapf(err, "failed to create file %q", logFileName)
+ }
+ defer logFile.Close()
+ if err = label.SetFileLabel(logFileName, fileLabel); err != nil {
+ return errors.Wrapf(err, "failed to label file %q", logFileName)
+ }
+
+ return nil
+}
+
+// CRRuntimeSupportsCheckpointRestore tests if the given runtime at 'runtimePath'
+// supports checkpointing. The checkpoint restore interface has no definition
+// but crun implements all commands just as runc does. Whathh runc does it the
+// official definition of the checkpoint/restore interface.
+func CRRuntimeSupportsCheckpointRestore(runtimePath string) bool {
+ // Check if the runtime implements checkpointing. Currently only
+ // runc's and crun's checkpoint/restore implementation is supported.
+ cmd := exec.Command(runtimePath, "checkpoint", "--help")
+ if err := cmd.Start(); err != nil {
+ return false
+ }
+ if err := cmd.Wait(); err == nil {
+ return true
+ }
+ return false
+}
--
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