support tag@digest notation

Vendor in the latest HEAd of containers/common to implicitly support the
tag@digest notation for images.  To remain compatible with Docker, the
tag will be stripped off the image reference and is entirely ignored.

Fixes: #6721
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

vendor/github.com/containers/common/pkg/config/systemd.go

@@ -3,11 +3,23 @@
 package config
 
 import (
+	"io/ioutil"
+	"strings"
+	"sync"
+
 	"github.com/containers/common/pkg/cgroupv2"
 	"github.com/containers/storage/pkg/unshare"
 )
 
+var (
+	systemdOnce sync.Once
+	usesSystemd bool
+)
+
 func defaultCgroupManager() string {
+	if !useSystemd() {
+		return CgroupfsCgroupsManager
+	}
 	enabled, err := cgroupv2.Enabled()
 	if err == nil && !enabled && unshare.IsRootless() {
 		return CgroupfsCgroupsManager
@@ -15,6 +27,32 @@ func defaultCgroupManager() string {
 
 	return SystemdCgroupsManager
 }
+
 func defaultEventsLogger() string {
-	return "journald"
+	if useSystemd() {
+		return "journald"
+	}
+	return "file"
+}
+
+func defaultLogDriver() string {
+	// If we decide to change the default for logdriver, it should be done here.
+	if useSystemd() {
+		return DefaultLogDriver
+	}
+
+	return DefaultLogDriver
+
+}
+
+func useSystemd() bool {
+	systemdOnce.Do(func() {
+		dat, err := ioutil.ReadFile("/proc/1/comm")
+		if err == nil {
+			val := strings.TrimSuffix(string(dat), "\n")
+			usesSystemd = (val == "systemd")
+		}
+		return
+	})
+	return usesSystemd
 }