Verify that used OCI runtime supports checkpoint

To be able to use OCI runtimes which do not implement checkpoint/restore
this adds a check to the checkpoint code path and the checkpoint/restore
tests to see if it knows about the checkpoint subcommand. If the used
OCI runtime does not implement checkpoint/restore the tests are skipped
and the actual 'podman container checkpoint' returns an error.

Signed-off-by: Adrian Reber <areber@redhat.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/libpod/oci.go b/libpod/oci.go
index 26d2c6ef1..e4ed66928 100644
--- a/libpod/oci.go
+++ b/libpod/oci.go
@@ -890,3 +890,16 @@ func (r *OCIRuntime) checkpointContainer(ctr *Container, options ContainerCheckp
 	args = append(args, ctr.ID())
 	return utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, nil, r.path, args...)
 }
+
+func (r *OCIRuntime) featureCheckCheckpointing() bool {
+	// Check if the runtime implements checkpointing. Currently only
+	// runc's checkpoint/restore implementation is supported.
+	cmd := exec.Command(r.path, "checkpoint", "-h")
+	if err := cmd.Start(); err != nil {
+		return false
+	}
+	if err := cmd.Wait(); err == nil {
+		return true
+	}
+	return false
+}