Fix pod sharing for utsmode

We should be sharing cgroups namespace by default in pods
uts namespace sharing was broken in pods.

Create a new libpod/pkg/namespaces for handling of namespace fields
in containers

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

Closes: #1418
Approved by: mheon

pkg/namespaces/namespaces.go

@@ -0,0 +1,219 @@
+package namespaces
+
+import (
+	"strings"
+)
+
+// UsernsMode represents userns mode in the container.
+type UsernsMode string
+
+// IsHost indicates whether the container uses the host's userns.
+func (n UsernsMode) IsHost() bool {
+	return n == "host"
+}
+
+// IsPrivate indicates whether the container uses the a private userns.
+func (n UsernsMode) IsPrivate() bool {
+	return !(n.IsHost())
+}
+
+// Valid indicates whether the userns is valid.
+func (n UsernsMode) Valid() bool {
+	parts := strings.Split(string(n), ":")
+	switch mode := parts[0]; mode {
+	case "", "host":
+	default:
+		return false
+	}
+	return true
+}
+
+// UTSMode represents the UTS namespace of the container.
+type UTSMode string
+
+// IsPrivate indicates whether the container uses its private UTS namespace.
+func (n UTSMode) IsPrivate() bool {
+	return !(n.IsHost())
+}
+
+// IsHost indicates whether the container uses the host's UTS namespace.
+func (n UTSMode) IsHost() bool {
+	return n == "host"
+}
+
+// IsContainer indicates whether the container uses a container's UTS namespace.
+func (n UTSMode) IsContainer() bool {
+	parts := strings.SplitN(string(n), ":", 2)
+	return len(parts) > 1 && parts[0] == "container"
+}
+
+// Container returns the name of the container whose uts namespace is going to be used.
+func (n UTSMode) Container() string {
+	parts := strings.SplitN(string(n), ":", 2)
+	if len(parts) > 1 {
+		return parts[1]
+	}
+	return ""
+}
+
+// Valid indicates whether the UTS namespace is valid.
+func (n UTSMode) Valid() bool {
+	parts := strings.Split(string(n), ":")
+	switch mode := parts[0]; mode {
+	case "", "host":
+	case "container":
+		if len(parts) != 2 || parts[1] == "" {
+			return false
+		}
+	default:
+		return false
+	}
+	return true
+}
+
+// IpcMode represents the container ipc stack.
+type IpcMode string
+
+// IsPrivate indicates whether the container uses its own private ipc namespace which can not be shared.
+func (n IpcMode) IsPrivate() bool {
+	return n == "private"
+}
+
+// IsHost indicates whether the container shares the host's ipc namespace.
+func (n IpcMode) IsHost() bool {
+	return n == "host"
+}
+
+// IsShareable indicates whether the container's ipc namespace can be shared with another container.
+func (n IpcMode) IsShareable() bool {
+	return n == "shareable"
+}
+
+// IsContainer indicates whether the container uses another container's ipc namespace.
+func (n IpcMode) IsContainer() bool {
+	parts := strings.SplitN(string(n), ":", 2)
+	return len(parts) > 1 && parts[0] == "container"
+}
+
+// IsNone indicates whether container IpcMode is set to "none".
+func (n IpcMode) IsNone() bool {
+	return n == "none"
+}
+
+// IsEmpty indicates whether container IpcMode is empty
+func (n IpcMode) IsEmpty() bool {
+	return n == ""
+}
+
+// Valid indicates whether the ipc mode is valid.
+func (n IpcMode) Valid() bool {
+	return n.IsEmpty() || n.IsNone() || n.IsPrivate() || n.IsHost() || n.IsShareable() || n.IsContainer()
+}
+
+// Container returns the name of the container ipc stack is going to be used.
+func (n IpcMode) Container() string {
+	parts := strings.SplitN(string(n), ":", 2)
+	if len(parts) > 1 && parts[0] == "container" {
+		return parts[1]
+	}
+	return ""
+}
+
+// PidMode represents the pid namespace of the container.
+type PidMode string
+
+// IsPrivate indicates whether the container uses its own new pid namespace.
+func (n PidMode) IsPrivate() bool {
+	return !(n.IsHost() || n.IsContainer())
+}
+
+// IsHost indicates whether the container uses the host's pid namespace.
+func (n PidMode) IsHost() bool {
+	return n == "host"
+}
+
+// IsContainer indicates whether the container uses a container's pid namespace.
+func (n PidMode) IsContainer() bool {
+	parts := strings.SplitN(string(n), ":", 2)
+	return len(parts) > 1 && parts[0] == "container"
+}
+
+// Valid indicates whether the pid namespace is valid.
+func (n PidMode) Valid() bool {
+	parts := strings.Split(string(n), ":")
+	switch mode := parts[0]; mode {
+	case "", "host":
+	case "container":
+		if len(parts) != 2 || parts[1] == "" {
+			return false
+		}
+	default:
+		return false
+	}
+	return true
+}
+
+// Container returns the name of the container whose pid namespace is going to be used.
+func (n PidMode) Container() string {
+	parts := strings.SplitN(string(n), ":", 2)
+	if len(parts) > 1 {
+		return parts[1]
+	}
+	return ""
+}
+
+// NetworkMode represents the container network stack.
+type NetworkMode string
+
+// IsNone indicates whether container isn't using a network stack.
+func (n NetworkMode) IsNone() bool {
+	return n == "none"
+}
+
+// IsHost indicates whether the container uses the host's network stack.
+func (n NetworkMode) IsHost() bool {
+	return n == "host"
+}
+
+// IsDefault indicates whether container uses the default network stack.
+func (n NetworkMode) IsDefault() bool {
+	return n == "default"
+}
+
+// IsPrivate indicates whether container uses its private network stack.
+func (n NetworkMode) IsPrivate() bool {
+	return !(n.IsHost() || n.IsContainer())
+}
+
+// IsContainer indicates whether container uses a container network stack.
+func (n NetworkMode) IsContainer() bool {
+	parts := strings.SplitN(string(n), ":", 2)
+	return len(parts) > 1 && parts[0] == "container"
+}
+
+// ConnectedContainer is the id of the container which network this container is connected to.
+func (n NetworkMode) ConnectedContainer() string {
+	parts := strings.SplitN(string(n), ":", 2)
+	if len(parts) > 1 {
+		return parts[1]
+	}
+	return ""
+}
+
+//UserDefined indicates user-created network
+func (n NetworkMode) UserDefined() string {
+	if n.IsUserDefined() {
+		return string(n)
+	}
+	return ""
+}
+
+// IsBridge indicates whether container uses the bridge network stack
+func (n NetworkMode) IsBridge() bool {
+	return n == "bridge"
+}
+
+// IsUserDefined indicates user-created network
+func (n NetworkMode) IsUserDefined() bool {
+	return !n.IsDefault() && !n.IsBridge() && !n.IsHost() && !n.IsNone() && !n.IsContainer()
+}