Add API for sharing namespaces

Remove existing code for sharing namespaces and replace with use
of this API

Signed-off-by: Matthew Heon <matthew.heon@gmail.com>

Closes: #220
Approved by: rhatdan

cmd/podman/spec.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"encoding/json"
-	"fmt"
 	"io/ioutil"
 	"strings"
 
@@ -53,21 +52,10 @@ func blockAccessToKernelFilesystems(config *createConfig, g *generate.Generator)
 func addPidNS(config *createConfig, g *generate.Generator) error {
 	pidMode := config.PidMode
 	if pidMode.IsHost() {
-		return g.RemoveLinuxNamespace(libpod.PIDNamespace)
+		return g.RemoveLinuxNamespace(string(spec.PIDNamespace))
 	}
 	if pidMode.IsContainer() {
-		ctr, err := config.Runtime.LookupContainer(pidMode.Container())
-		if err != nil {
-			return errors.Wrapf(err, "container %q not found", pidMode.Container())
-		}
-		pid, err := ctr.PID()
-		if err != nil {
-			return errors.Wrapf(err, "Failed to get pid of container %q", pidMode.Container())
-		}
-		pidNsPath := fmt.Sprintf("/proc/%d/ns/pid", pid)
-		if err := g.AddOrReplaceLinuxNamespace(libpod.PIDNamespace, pidNsPath); err != nil {
-			return err
-		}
+		logrus.Debug("using container pidmode")
 	}
 	return nil
 }
@@ -76,7 +64,7 @@ func addNetNS(config *createConfig, g *generate.Generator) error {
 	netMode := config.NetMode
 	if netMode.IsHost() {
 		logrus.Debug("Using host netmode")
-		return g.RemoveLinuxNamespace(libpod.NetNamespace)
+		return g.RemoveLinuxNamespace(spec.NetworkNamespace)
 	} else if netMode.IsNone() {
 		logrus.Debug("Using none netmode")
 		return nil
@@ -85,18 +73,6 @@ func addNetNS(config *createConfig, g *generate.Generator) error {
 		return nil
 	} else if netMode.IsContainer() {
 		logrus.Debug("Using container netmode")
-		ctr, err := config.Runtime.LookupContainer(netMode.ConnectedContainer())
-		if err != nil {
-			return errors.Wrapf(err, "container %q not found", netMode.ConnectedContainer())
-		}
-		pid, err := ctr.PID()
-		if err != nil {
-			return errors.Wrapf(err, "Failed to get pid of container %q", netMode.ConnectedContainer())
-		}
-		nsPath := fmt.Sprintf("/proc/%d/ns/net", pid)
-		if err := g.AddOrReplaceLinuxNamespace(libpod.NetNamespace, nsPath); err != nil {
-			return err
-		}
 	} else {
 		return errors.Errorf("unknown network mode")
 	}
@@ -106,7 +82,7 @@ func addNetNS(config *createConfig, g *generate.Generator) error {
 func addUTSNS(config *createConfig, g *generate.Generator) error {
 	utsMode := config.UtsMode
 	if utsMode.IsHost() {
-		return g.RemoveLinuxNamespace(libpod.UTSNamespace)
+		return g.RemoveLinuxNamespace(spec.UTSNamespace)
 	}
 	return nil
 }
@@ -114,21 +90,10 @@ func addUTSNS(config *createConfig, g *generate.Generator) error {
 func addIpcNS(config *createConfig, g *generate.Generator) error {
 	ipcMode := config.IpcMode
 	if ipcMode.IsHost() {
-		return g.RemoveLinuxNamespace(libpod.IPCNamespace)
+		return g.RemoveLinuxNamespace(spec.IPCNamespace)
 	}
 	if ipcMode.IsContainer() {
-		ctr, err := config.Runtime.LookupContainer(ipcMode.Container())
-		if err != nil {
-			return errors.Wrapf(err, "container %q not found", ipcMode.Container())
-		}
-		pid, err := ctr.PID()
-		if err != nil {
-			return errors.Wrapf(err, "Failed to get pid of container %q", ipcMode.Container())
-		}
-		nsPath := fmt.Sprintf("/proc/%d/ns/ipc", pid)
-		if err := g.AddOrReplaceLinuxNamespace(libpod.IPCNamespace, nsPath); err != nil {
-			return err
-		}
+		logrus.Debug("Using container ipcmode")
 	}
 
 	return nil
@@ -580,9 +545,33 @@ func (c *createConfig) GetContainerCreateOptions() ([]libpod.CtrCreateOption, er
 		options = append(options, libpod.WithName(c.Name))
 	}
 	// TODO parse ports into libpod format and include
-	if !c.NetMode.IsHost() {
+	if !c.NetMode.IsHost() && !c.NetMode.IsContainer() {
 		options = append(options, libpod.WithNetNS([]ocicni.PortMapping{}))
+	} else if c.NetMode.IsContainer() {
+		connectedCtr, err := c.Runtime.LookupContainer(c.NetMode.ConnectedContainer())
+		if err != nil {
+			return nil, errors.Wrapf(err, "container %q not found", c.NetMode.ConnectedContainer())
 		}
+
+		options = append(options, libpod.WithNetNSFrom(connectedCtr))
+	}
+	if c.PidMode.IsContainer() {
+		connectedCtr, err := c.Runtime.LookupContainer(c.PidMode.Container())
+		if err != nil {
+			return nil, errors.Wrapf(err, "container %q not found", c.PidMode.Container())
+		}
+
+		options = append(options, libpod.WithPIDNSFrom(connectedCtr))
+	}
+	if c.IpcMode.IsContainer() {
+		connectedCtr, err := c.Runtime.LookupContainer(c.IpcMode.Container())
+		if err != nil {
+			return nil, errors.Wrapf(err, "container %q not found", c.IpcMode.Container())
+		}
+
+		options = append(options, libpod.WithIPCNSFrom(connectedCtr))
+	}
+
 	options = append(options, libpod.WithStopSignal(c.StopSignal))
 	options = append(options, libpod.WithStopTimeout(c.StopTimeout))
 	return options, nil

libpod/container.go

@@ -133,7 +133,6 @@ type Container struct {
 // TODO enable pod support
 // TODO Add readonly support
 // TODO add SHM size support
-// TODO add shared namespace support
 
 // containerRuntimeInfo contains the current state of the container
 // It is stored on disk in a tmpfs and recreated on reboot

libpod/options.go

@@ -1,7 +1,6 @@
 package libpod
 
 import (
-	"fmt"
 	"path/filepath"
 	"regexp"
 	"syscall"
@@ -13,27 +12,9 @@ import (
 )
 
 var (
-	ctrNotImplemented = func(c *Container) error {
-		return fmt.Errorf("NOT IMPLEMENTED")
-	}
 	nameRegex = regexp.MustCompile("[a-zA-Z0-9_-]+")
 )
 
-const (
-	// IPCNamespace represents the IPC namespace
-	IPCNamespace = "ipc"
-	// MountNamespace represents the mount namespace
-	MountNamespace = "mount"
-	// NetNamespace represents the network namespace
-	NetNamespace = "network"
-	// PIDNamespace represents the PID namespace
-	PIDNamespace = "pid"
-	// UserNamespace represents the user namespace
-	UserNamespace = "user"
-	// UTSNamespace represents the UTS namespace
-	UTSNamespace = "uts"
-)
-
 // Runtime Creation Options
 
 // WithStorageConfig uses the given configuration to set up container storage
@@ -341,15 +322,6 @@ func WithStdin() CtrCreateOption {
 	}
 }
 
-// WithSharedNamespaces sets a container to share namespaces with another
-// container. If the from container belongs to a pod, the new container will
-// be added to the pod.
-// By default no namespaces are shared. To share a namespace, add the Namespace
-// string constant to the map as a key
-func WithSharedNamespaces(from *Container, namespaces map[string]string) CtrCreateOption {
-	return ctrNotImplemented
-}
-
 // WithPod adds the container to a pod
 func (r *Runtime) WithPod(pod *Pod) CtrCreateOption {
 	return func(ctr *Container) error {
@@ -434,6 +406,164 @@ func WithStopTimeout(timeout uint) CtrCreateOption {
 	}
 }
 
+// WithIPCNSFrom indicates the the container should join the IPC namespace of
+// the given container
+func WithIPCNSFrom(nsCtr *Container) CtrCreateOption {
+	return func(ctr *Container) error {
+		if ctr.valid {
+			return ErrCtrFinalized
+		}
+
+		if !nsCtr.valid {
+			return ErrCtrRemoved
+		}
+
+		if nsCtr.ID() == ctr.ID() {
+			return errors.Wrapf(ErrInvalidArg, "must specify another container")
+		}
+
+		ctr.config.IPCNsCtr = nsCtr.ID()
+
+		return nil
+	}
+}
+
+// WithMountNSFrom indicates the the container should join the mount namespace
+// of the given container
+func WithMountNSFrom(nsCtr *Container) CtrCreateOption {
+	return func(ctr *Container) error {
+		if ctr.valid {
+			return ErrCtrFinalized
+		}
+
+		if !nsCtr.valid {
+			return ErrCtrRemoved
+		}
+
+		if nsCtr.ID() == ctr.ID() {
+			return errors.Wrapf(ErrInvalidArg, "must specify another container")
+		}
+
+		ctr.config.MountNsCtr = nsCtr.ID()
+
+		return nil
+	}
+}
+
+// WithNetNSFrom indicates the the container should join the network namespace
+// of the given container
+func WithNetNSFrom(nsCtr *Container) CtrCreateOption {
+	return func(ctr *Container) error {
+		if ctr.valid {
+			return ErrCtrFinalized
+		}
+
+		if !nsCtr.valid {
+			return ErrCtrRemoved
+		}
+
+		if nsCtr.ID() == ctr.ID() {
+			return errors.Wrapf(ErrInvalidArg, "must specify another container")
+		}
+
+		if ctr.config.CreateNetNS {
+			return errors.Wrapf(ErrInvalidArg, "cannot join another container's net ns as we are making a new net ns")
+		}
+
+		ctr.config.NetNsCtr = nsCtr.ID()
+
+		return nil
+	}
+}
+
+// WithPIDNSFrom indicates the the container should join the PID namespace of
+// the given container
+func WithPIDNSFrom(nsCtr *Container) CtrCreateOption {
+	return func(ctr *Container) error {
+		if ctr.valid {
+			return ErrCtrFinalized
+		}
+
+		if !nsCtr.valid {
+			return ErrCtrRemoved
+		}
+
+		if nsCtr.ID() == ctr.ID() {
+			return errors.Wrapf(ErrInvalidArg, "must specify another container")
+		}
+
+		ctr.config.PIDNsCtr = nsCtr.ID()
+
+		return nil
+	}
+}
+
+// WithUserNSFrom indicates the the container should join the user namespace of
+// the given container
+func WithUserNSFrom(nsCtr *Container) CtrCreateOption {
+	return func(ctr *Container) error {
+		if ctr.valid {
+			return ErrCtrFinalized
+		}
+
+		if !nsCtr.valid {
+			return ErrCtrRemoved
+		}
+
+		if nsCtr.ID() == ctr.ID() {
+			return errors.Wrapf(ErrInvalidArg, "must specify another container")
+		}
+
+		ctr.config.UserNsCtr = nsCtr.ID()
+
+		return nil
+	}
+}
+
+// WithUTSNSFrom indicates the the container should join the UTS namespace of
+// the given container
+func WithUTSNSFrom(nsCtr *Container) CtrCreateOption {
+	return func(ctr *Container) error {
+		if ctr.valid {
+			return ErrCtrFinalized
+		}
+
+		if !nsCtr.valid {
+			return ErrCtrRemoved
+		}
+
+		if nsCtr.ID() == ctr.ID() {
+			return errors.Wrapf(ErrInvalidArg, "must specify another container")
+		}
+
+		ctr.config.UTSNsCtr = nsCtr.ID()
+
+		return nil
+	}
+}
+
+// WithCgroupNSFrom indicates the the container should join the CGroup namespace
+// of the given container
+func WithCgroupNSFrom(nsCtr *Container) CtrCreateOption {
+	return func(ctr *Container) error {
+		if ctr.valid {
+			return ErrCtrFinalized
+		}
+
+		if !nsCtr.valid {
+			return ErrCtrRemoved
+		}
+
+		if nsCtr.ID() == ctr.ID() {
+			return errors.Wrapf(ErrInvalidArg, "must specify another container")
+		}
+
+		ctr.config.CgroupNsCtr = nsCtr.ID()
+
+		return nil
+	}
+}
+
 // WithNetNS indicates that the container should be given a new network
 // namespace with a minimal configuration
 // An optional array of port mappings can be provided
@@ -443,6 +573,10 @@ func WithNetNS(portMappings []ocicni.PortMapping) CtrCreateOption {
 			return ErrCtrFinalized
 		}
 
+		if ctr.config.NetNsCtr != "" {
+			return errors.Wrapf(ErrInvalidArg, "container is already set to join another container's net ns, cannot create a new net ns")
+		}
+
 		ctr.config.CreateNetNS = true
 		copy(ctr.config.PortMappings, portMappings)