podman pod create --uts support

add support for the --uts flag in pod create, allowing users to avoid
issues with default values in containers.conf.

uts follows the same format as other namespace flags:
--uts=private (default), --uts=host, --uts=ns:PATH

resolves #13714

Signed-off-by: Charlie Doern <cdoern@redhat.com>

4 files changed, 54 insertions, 22 deletions

diff --git a/libpod/container.go b/libpod/container.go
index 0619471b4..1e2dad3f3 100644
--- a/libpod/container.go
+++ b/libpod/container.go
@@ -1336,3 +1336,52 @@ func (c *Container) getNetworkStatus() map[string]types.StatusBlock {
 	}
 	return nil
 }
+
+func (c *Container) NamespaceMode(ns spec.LinuxNamespaceType, ctrSpec *spec.Spec) string {
+	switch ns {
+	case spec.UTSNamespace:
+		if c.config.UTSNsCtr != "" {
+			return fmt.Sprintf("container:%s", c.config.UTSNsCtr)
+		}
+	case spec.CgroupNamespace:
+		if c.config.CgroupNsCtr != "" {
+			return fmt.Sprintf("container:%s", c.config.CgroupNsCtr)
+		}
+	case spec.IPCNamespace:
+		if c.config.IPCNsCtr != "" {
+			return fmt.Sprintf("container:%s", c.config.IPCNsCtr)
+		}
+	case spec.PIDNamespace:
+		if c.config.PIDNsCtr != "" {
+			return fmt.Sprintf("container:%s", c.config.PIDNsCtr)
+		}
+	case spec.UserNamespace:
+		if c.config.UserNsCtr != "" {
+			return fmt.Sprintf("container:%s", c.config.UserNsCtr)
+		}
+	case spec.NetworkNamespace:
+		if c.config.NetNsCtr != "" {
+			return fmt.Sprintf("container:%s", c.config.NetNsCtr)
+		}
+	case spec.MountNamespace:
+		if c.config.MountNsCtr != "" {
+			return fmt.Sprintf("container:%s", c.config.MountNsCtr)
+		}
+	}
+
+	if ctrSpec.Linux != nil {
+		// Locate the spec's given namespace.
+		// If there is none, it's namespace=host.
+		// If there is one and it has a path, it's "ns:".
+		// If there is no path, it's default - the empty string.
+		for _, availableNS := range ctrSpec.Linux.Namespaces {
+			if availableNS.Type == ns {
+				if availableNS.Path != "" {
+					return fmt.Sprintf("ns:%s", availableNS.Path)
+				}
+				return "private"
+			}
+		}
+	}
+	return "host"
+}
diff --git a/libpod/container_inspect.go b/libpod/container_inspect.go
index 93240812d..7ccd9fdbf 100644
--- a/libpod/container_inspect.go
+++ b/libpod/container_inspect.go
@@ -794,28 +794,8 @@ func (c *Container) generateInspectContainerHostConfig(ctrSpec *spec.Spec, named
 	hostConfig.PidMode = pidMode
 
 	// UTS namespace mode
-	utsMode := ""
-	if c.config.UTSNsCtr != "" {
-		utsMode = fmt.Sprintf("container:%s", c.config.UTSNsCtr)
-	} else if ctrSpec.Linux != nil {
-		// Locate the spec's UTS namespace.
-		// If there is none, it's uts=host.
-		// If there is one and it has a path, it's "ns:".
-		// If there is no path, it's default - the empty string.
-		for _, ns := range ctrSpec.Linux.Namespaces {
-			if ns.Type == spec.UTSNamespace {
-				if ns.Path != "" {
-					utsMode = fmt.Sprintf("ns:%s", ns.Path)
-				} else {
-					utsMode = "private"
-				}
-				break
-			}
-		}
-		if utsMode == "" {
-			utsMode = "host"
-		}
-	}
+	utsMode := c.NamespaceMode(spec.UTSNamespace, ctrSpec)
+
 	hostConfig.UTSMode = utsMode
 
 	// User namespace mode
diff --git a/libpod/define/pod_inspect.go b/libpod/define/pod_inspect.go
index 935e0f5f9..2afef48c4 100644
--- a/libpod/define/pod_inspect.go
+++ b/libpod/define/pod_inspect.go
@@ -122,6 +122,8 @@ type InspectPodInfraConfig struct {
 	PidNS string `json:"pid_ns,omitempty"`
 	// UserNS is the usernamespace that all the containers in the pod will join.
 	UserNS string `json:"userns,omitempty"`
+	// UtsNS is the uts namespace that all containers in the pod will join
+	UtsNS string `json:"uts_ns,omitempty"`
 }
 
 // InspectPodContainerInfo contains information on a container in a pod.
diff --git a/libpod/pod_api.go b/libpod/pod_api.go
index f06e62007..29dc22890 100644
--- a/libpod/pod_api.go
+++ b/libpod/pod_api.go
@@ -676,6 +676,7 @@ func (p *Pod) Inspect() (*define.InspectPodData, error) {
 		infraConfig.CPUSetCPUs = p.ResourceLim().CPU.Cpus
 		infraConfig.PidNS = p.NamespaceMode(specs.PIDNamespace)
 		infraConfig.UserNS = p.NamespaceMode(specs.UserNamespace)
+		infraConfig.UtsNS = p.NamespaceMode(specs.UTSNamespace)
 		namedVolumes, mounts := infra.SortUserVolumes(infra.config.Spec)
 		inspectMounts, err = infra.GetMounts(namedVolumes, infra.config.ImageVolumes, mounts)
 		infraSecurity = infra.GetSecurityOptions()