podman: handle namespaces specified on the CLI

and handle differently the user namespace as it supports additional
options.

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

cmd/podman/common/create.go

@@ -49,8 +49,9 @@ func GetCreateFlags(cf *ContainerCLIOpts) *pflag.FlagSet {
 		"cap-drop", []string{},
 		"Drop capabilities from the container",
 	)
+	cgroupNS := ""
 	createFlags.StringVar(
-		&cf.CGroupsNS,
+		&cgroupNS,
 		"cgroupns", containerConfig.CgroupNS(),
 		"cgroup namespace to use",
 	)
@@ -247,8 +248,9 @@ func GetCreateFlags(cf *ContainerCLIOpts) *pflag.FlagSet {
 		"interactive", "i", false,
 		"Keep STDIN open even if not attached",
 	)
+	ipcNS := ""
 	createFlags.StringVar(
-		&cf.IPC,
+		&ipcNS,
 		"ipc", containerConfig.IPCNS(),
 		"IPC namespace to use",
 	)
@@ -329,8 +331,9 @@ func GetCreateFlags(cf *ContainerCLIOpts) *pflag.FlagSet {
 		"use `OS` instead of the running OS for choosing images",
 	)
 	// markFlagHidden(createFlags, "override-os")
+	pid := ""
 	createFlags.StringVar(
-		&cf.PID,
+		&pid,
 		"pid", containerConfig.PidNS(),
 		"PID namespace to use",
 	)
@@ -461,13 +464,15 @@ func GetCreateFlags(cf *ContainerCLIOpts) *pflag.FlagSet {
 		"user", "u", "",
 		"Username or UID (format: <name|uid>[:<group|gid>])",
 	)
+	userNS := ""
 	createFlags.StringVar(
-		&cf.UserNS,
+		&userNS,
 		"userns", containerConfig.Containers.UserNS,
 		"User namespace to use",
 	)
+	utsNS := ""
 	createFlags.StringVar(
-		&cf.UTS,
+		&utsNS,
 		"uts", containerConfig.Containers.UTSNS,
 		"UTS namespace to use",
 	)

cmd/podman/common/specgen.go

@@ -222,55 +222,28 @@ func FillOutSpecGen(s *specgen.SpecGenerator, c *ContainerCLIOpts, args []string
 	s.PortMappings = ep
 	s.Pod = c.Pod
 
-	//s.CgroupNS = specgen.Namespace{
-	//	NSMode: ,
-	//	Value:  "",
-	//}
-
-	//s.UserNS = specgen.Namespace{}
-
-	// Kernel Namespaces
-	// TODO Fix handling of namespace from pod
-	// Instead of integrating here, should be done in libpod
-	// However, that also involves setting up security opts
-	// when the pod's namespace is integrated
-	//namespaces = map[string]string{
-	//	"cgroup": c.CGroupsNS,
-	//	"pid":    c.PID,
-	//	//"net":    c.Net.Network.Value,   // TODO need help here
-	//	"ipc":  c.IPC,
-	//	"user": c.User,
-	//	"uts":  c.UTS,
-	//}
-	//
-	//if len(c.PID) > 0 {
-	//	split := strings.SplitN(c.PID, ":", 2)
-	//	// need a way to do thsi
-	//	specgen.Namespace{
-	//		NSMode: split[0],
-	//	}
-	//	//Value:  split1 if len allows
-	//}
-	// TODO this is going to have be done after things like pod creation are done because
-	// pod creation changes these values.
-	//pidMode := ns.PidMode(namespaces["pid"])
-	//usernsMode := ns.UsernsMode(namespaces["user"])
-	//utsMode := ns.UTSMode(namespaces["uts"])
-	//cgroupMode := ns.CgroupMode(namespaces["cgroup"])
-	//ipcMode := ns.IpcMode(namespaces["ipc"])
-	//// Make sure if network is set to container namespace, port binding is not also being asked for
-	//netMode := ns.NetworkMode(namespaces["net"])
-	//if netMode.IsContainer() {
-	//	if len(portBindings) > 0 {
-	//		return nil, errors.Errorf("cannot set port bindings on an existing container network namespace")
-	//	}
-	//}
-
-	// TODO Remove when done with namespaces for realz
-	// Setting a default for IPC to get this working
-	s.IpcNS = specgen.Namespace{
-		NSMode: specgen.Private,
-		Value:  "",
+	for k, v := range map[string]*specgen.Namespace{
+		c.IPC:       &s.IpcNS,
+		c.PID:       &s.PidNS,
+		c.UTS:       &s.UtsNS,
+		c.CGroupsNS: &s.CgroupNS,
+	} {
+		if k != "" {
+			*v, err = specgen.ParseNamespace(k)
+			if err != nil {
+				return err
+			}
+		}
+	}
+	// userns must be treated differently
+	if c.UserNS != "" {
+		s.UserNS, err = specgen.ParseUserNamespace(c.UserNS)
+		if err != nil {
+			return err
+		}
+	}
+	if c.Net != nil {
+		s.NetNS = c.Net.Network
 	}
 
 	// TODO this is going to have to be done the libpod/server end of things

cmd/podman/containers/create.go

@@ -149,6 +149,21 @@ func createInit(c *cobra.Command) error {
 	if c.Flag("no-hosts").Changed && c.Flag("add-host").Changed {
 		return errors.Errorf("--no-hosts and --add-host cannot be set together")
 	}
+	if c.Flag("userns").Changed {
+		cliVals.UserNS = c.Flag("userns").Value.String()
+	}
+	if c.Flag("ipc").Changed {
+		cliVals.IPC = c.Flag("ipc").Value.String()
+	}
+	if c.Flag("uts").Changed {
+		cliVals.UTS = c.Flag("uts").Value.String()
+	}
+	if c.Flag("pid").Changed {
+		cliVals.PID = c.Flag("pid").Value.String()
+	}
+	if c.Flag("cgroupns").Changed {
+		cliVals.CGroupsNS = c.Flag("cgroupns").Value.String()
+	}
 
 	// Docker-compatibility: the "-h" flag for run/create is reserved for
 	// the hostname (see https://github.com/containers/libpod/issues/1367).

pkg/specgen/container_validate.go

@@ -129,7 +129,7 @@ func (s *SpecGenerator) Validate() error {
 	if err := s.CgroupNS.validate(); err != nil {
 		return err
 	}
-	if err := s.UserNS.validate(); err != nil {
+	if err := validateUserNS(&s.UserNS); err != nil {
 		return err
 	}
 

pkg/specgen/generate/namespaces.go

@@ -58,8 +58,7 @@ func GetDefaultNamespaceMode(nsType string, cfg *config.Config, pod *libpod.Pod)
 		case "uts":
 			return specgen.ParseNamespace(cfg.Containers.UTSNS)
 		case "user":
-			// TODO: This may not work for --userns=auto
-			return specgen.ParseNamespace(cfg.Containers.UserNS)
+			return specgen.ParseUserNamespace(cfg.Containers.UserNS)
 		case "net":
 			ns, _, err := specgen.ParseNetworkNamespace(cfg.Containers.NetNS)
 			return ns, err

pkg/specgen/namespaces.go

@@ -33,6 +33,11 @@ const (
 	// Slirp indicates that a slirp4netns network stack should
 	// be used
 	Slirp NamespaceMode = "slirp4netns"
+	// KeepId indicates a user namespace to keep the owner uid inside
+	// of the namespace itself
+	KeepID NamespaceMode = "keep-id"
+	// KeepId indicates to automatically create a user namespace
+	Auto NamespaceMode = "auto"
 )
 
 // Namespace describes the namespace
@@ -71,6 +76,16 @@ func (n *Namespace) IsPod() bool {
 func (n *Namespace) IsPrivate() bool {
 	return n.NSMode == Private
 }
+func validateUserNS(n *Namespace) error {
+	if n == nil {
+		return nil
+	}
+	switch n.NSMode {
+	case Auto, KeepID:
+		return nil
+	}
+	return n.validate()
+}
 
 func validateNetNS(n *Namespace) error {
 	if n == nil {
@@ -158,6 +173,30 @@ func ParseNamespace(ns string) (Namespace, error) {
 	return toReturn, nil
 }
 
+// ParseUserNamespace parses a user namespace specification in string
+// form.
+func ParseUserNamespace(ns string) (Namespace, error) {
+	toReturn := Namespace{}
+	switch {
+	case ns == "auto":
+		toReturn.NSMode = Auto
+		return toReturn, nil
+	case strings.HasPrefix(ns, "auto:"):
+		split := strings.SplitN(ns, ":", 2)
+		if len(split) != 2 {
+			return toReturn, errors.Errorf("invalid setting for auto: mode")
+		}
+		toReturn.NSMode = KeepID
+		toReturn.Value = split[1]
+		return toReturn, nil
+	case ns == "keep-id":
+		toReturn.NSMode = KeepID
+		toReturn.NSMode = FromContainer
+		return toReturn, nil
+	}
+	return ParseNamespace(ns)
+}
+
 // ParseNetworkNamespace parses a network namespace specification in string
 // form.
 // Returns a namespace and (optionally) a list of CNI networks to join.