validation: add hostname validation

Signed-off-by: Ma Shimiao <mashimiao.fnst@cn.fujitsu.com>

validate.go

@@ -83,7 +83,7 @@ func bundleValidate(spec rspec.Spec, rootfs string) {
 	checkPlatform(spec.Platform)
 	checkProcess(spec.Process, rootfs)
 	checkMounts(spec.Mounts, rootfs)
-	checkLinux(spec.Linux, rootfs)
+	checkLinux(spec.Linux, spec.Hostname, rootfs)
 }
 
 func checkSemVer(version string) {
@@ -152,7 +152,9 @@ func checkProcess(process rspec.Process, rootfs string) {
 }
 
 //Linux only
-func checkLinux(spec rspec.Linux, rootfs string) {
+func checkLinux(spec rspec.Linux, hostname string, rootfs string) {
+	utsExist := false
+
 	if len(spec.UIDMappings) > 5 {
 		logrus.Fatalf("Only 5 UID mappings are allowed (linux kernel restriction).")
 	}
@@ -163,9 +165,15 @@ func checkLinux(spec rspec.Linux, rootfs string) {
 	for index := 0; index < len(spec.Namespaces); index++ {
 		if !namespaceValid(spec.Namespaces[index]) {
 			logrus.Fatalf("Namespace %s is invalid.", spec.Namespaces[index])
+		} else if spec.Namespaces[index].Type == rspec.UTSNamespace {
+			utsExist = true
 		}
 	}
 
+	if !utsExist && hostname != "" {
+		logrus.Fatalf("New UTS namespace should to be created.")
+	}
+
 	for index := 0; index < len(spec.Devices); index++ {
 		if !deviceValid(spec.Devices[index]) {
 			logrus.Fatalf("Device %s is invalid.", spec.Devices[index].Path)