Golang Hooks.Start方法代码示例

// Exec implements the exec driver Driver interface,
// it calls libcontainer APIs to execute a container.
func (d *Driver) Exec(c *execdriver.Command, processConfig *execdriver.ProcessConfig, pipes *execdriver.Pipes, hooks execdriver.Hooks) (int, error) {
	active := d.activeContainers[c.ID]
	if active == nil {
		return -1, fmt.Errorf("No active container exists with ID %s", c.ID)
	}

	p := &libcontainer.Process{
		Args: append([]string{processConfig.Entrypoint}, processConfig.Arguments...),
		Env:  c.ProcessConfig.Env,
		Cwd:  c.WorkingDir,
		User: processConfig.User,
	}

	if processConfig.Privileged {
		p.Capabilities = execdriver.GetAllCapabilities()
	}
	// add CAP_ prefix to all caps for new libcontainer update to match
	// the spec format.
	for i, s := range p.Capabilities {
		if !strings.HasPrefix(s, "CAP_") {
			p.Capabilities[i] = fmt.Sprintf("CAP_%s", s)
		}
	}

	config := active.Config()
	if err := setupPipes(&config, processConfig, p, pipes); err != nil {
		return -1, err
	}

	if err := active.Start(p); err != nil {
		return -1, err
	}

	if hooks.Start != nil {
		pid, err := p.Pid()
		if err != nil {
			p.Signal(os.Kill)
			p.Wait()
			return -1, err
		}

		// A closed channel for OOM is returned here as it will be
		// non-blocking and return the correct result when read.
		chOOM := make(chan struct{})
		close(chOOM)
		hooks.Start(&c.ProcessConfig, pid, chOOM)
	}

	ps, err := p.Wait()
	if err != nil {
		exitErr, ok := err.(*exec.ExitError)
		if !ok {
			return -1, err
		}
		ps = exitErr.ProcessState
	}
	return utils.ExitStatus(ps.Sys().(syscall.WaitStatus)), nil
}

// Exec implements the exec driver Driver interface,
// it calls libcontainer APIs to execute a container.
func (d *Driver) Exec(c *execdriver.Command, processConfig *execdriver.ProcessConfig, pipes *execdriver.Pipes, hooks execdriver.Hooks) (int, error) {
	active := d.activeContainers[c.ID]
	if active == nil {
		return -1, fmt.Errorf("No active container exists with ID %s", c.ID)
	}

	p := &libcontainer.Process{
		Args: append([]string{processConfig.Entrypoint}, processConfig.Arguments...),
		Env:  c.ProcessConfig.Env,
		Cwd:  c.WorkingDir,
		User: processConfig.User,
	}

	if processConfig.Privileged {
		p.Capabilities = execdriver.GetAllCapabilities()
	}

	config := active.Config()
	if err := setupPipes(&config, processConfig, p, pipes); err != nil {
		return -1, err
	}

	if err := active.Start(p); err != nil {
		return -1, err
	}

	if hooks.Start != nil {
		pid, err := p.Pid()
		if err != nil {
			p.Signal(os.Kill)
			p.Wait()
			return -1, err
		}
		hooks.Start(&c.ProcessConfig, pid)
	}

	ps, err := p.Wait()
	if err != nil {
		exitErr, ok := err.(*exec.ExitError)
		if !ok {
			return -1, err
		}
		ps = exitErr.ProcessState
	}
	return utils.ExitStatus(ps.Sys().(syscall.WaitStatus)), nil
}

// Run implements the exec driver Driver interface,
// it calls libcontainer APIs to run a container.
func (d *Driver) Run(c *execdriver.Command, pipes *execdriver.Pipes, hooks execdriver.Hooks) (execdriver.ExitStatus, error) {
	// take the Command and populate the libcontainer.Config from it
	container, err := d.createContainer(c, hooks)
	if err != nil {
		return execdriver.ExitStatus{ExitCode: -1}, err
	}

	p := &libcontainer.Process{
		Args: append([]string{c.ProcessConfig.Entrypoint}, c.ProcessConfig.Arguments...),
		Env:  c.ProcessConfig.Env,
		Cwd:  c.WorkingDir,
		User: c.ProcessConfig.User,
	}

	if err := setupPipes(container, &c.ProcessConfig, p, pipes); err != nil {
		return execdriver.ExitStatus{ExitCode: -1}, err
	}

	cont, err := d.factory.Create(c.ID, container)
	if err != nil {
		return execdriver.ExitStatus{ExitCode: -1}, err
	}
	d.Lock()
	d.activeContainers[c.ID] = cont
	d.Unlock()
	defer func() {
		cont.Destroy()
		d.cleanContainer(c.ID)
	}()

	if err := cont.Start(p); err != nil {
		return execdriver.ExitStatus{ExitCode: -1}, err
	}

	oom := notifyOnOOM(cont)
	if hooks.Start != nil {
		pid, err := p.Pid()
		if err != nil {
			p.Signal(os.Kill)
			p.Wait()
			return execdriver.ExitStatus{ExitCode: -1}, err
		}
		hooks.Start(&c.ProcessConfig, pid, oom)
	}

	waitF := p.Wait
	if nss := cont.Config().Namespaces; !nss.Contains(configs.NEWPID) {
		// we need such hack for tracking processes with inherited fds,
		// because cmd.Wait() waiting for all streams to be copied
		waitF = waitInPIDHost(p, cont)
	}
	ps, err := waitF()
	if err != nil {
		execErr, ok := err.(*exec.ExitError)
		if !ok {
			return execdriver.ExitStatus{ExitCode: -1}, err
		}
		ps = execErr.ProcessState
	}
	cont.Destroy()
	_, oomKill := <-oom
	return execdriver.ExitStatus{ExitCode: utils.ExitStatus(ps.Sys().(syscall.WaitStatus)), OOMKilled: oomKill}, nil
}

// Exec implements the exec driver Driver interface.
func (d *Driver) Exec(c *execdriver.Command, processConfig *execdriver.ProcessConfig, pipes *execdriver.Pipes, hooks execdriver.Hooks) (int, error) {

	var (
		term     execdriver.Terminal
		err      error
		exitCode int32
		errno    uint32
	)

	active := d.activeContainers[c.ID]
	if active == nil {
		return -1, fmt.Errorf("Exec - No active container exists with ID %s", c.ID)
	}

	createProcessParms := hcsshim.CreateProcessParams{
		EmulateConsole:   processConfig.Tty, // Note NOT c.ProcessConfig.Tty
		WorkingDirectory: c.WorkingDir,
	}

	// Configure the environment for the process // Note NOT c.ProcessConfig.Env
	createProcessParms.Environment = setupEnvironmentVariables(processConfig.Env)

	// Create the commandline for the process // Note NOT c.ProcessConfig
	createProcessParms.CommandLine, err = createCommandLine(processConfig, false)

	if err != nil {
		return -1, err
	}

	// Start the command running in the container.
	pid, stdin, stdout, stderr, rc, err := hcsshim.CreateProcessInComputeSystem(c.ID, pipes.Stdin != nil, true, !processConfig.Tty, createProcessParms)
	if err != nil {
		// TODO Windows: TP4 Workaround. In Hyper-V containers, there is a limitation
		// of one exec per container. This should be fixed post TP4. CreateProcessInComputeSystem
		// will return a specific error which we handle here to give a good error message
		// back to the user instead of an inactionable "An invalid argument was supplied"
		if rc == hcsshim.Win32InvalidArgument {
			return -1, fmt.Errorf("The limit of docker execs per Hyper-V container has been exceeded")
		}
		logrus.Errorf("CreateProcessInComputeSystem() failed %s", err)
		return -1, err
	}

	// Now that the process has been launched, begin copying data to and from
	// the named pipes for the std handles.
	setupPipes(stdin, stdout, stderr, pipes)

	// Note NOT c.ProcessConfig.Tty
	if processConfig.Tty {
		term = NewTtyConsole(c.ID, pid)
	} else {
		term = NewStdConsole()
	}
	processConfig.Terminal = term

	// Invoke the start callback
	if hooks.Start != nil {
		// A closed channel for OOM is returned here as it will be
		// non-blocking and return the correct result when read.
		chOOM := make(chan struct{})
		close(chOOM)
		hooks.Start(&c.ProcessConfig, int(pid), chOOM)
	}

	if exitCode, errno, err = hcsshim.WaitForProcessInComputeSystem(c.ID, pid, hcsshim.TimeoutInfinite); err != nil {
		if errno == hcsshim.Win32PipeHasBeenEnded {
			logrus.Debugf("Exiting Run() after WaitForProcessInComputeSystem failed with recognised error 0x%X", errno)
			return hcsshim.WaitErrExecFailed, nil
		}
		logrus.Warnf("WaitForProcessInComputeSystem failed (container may have been killed): 0x%X %s", errno, err)
		return -1, err
	}

	logrus.Debugln("Exiting Run()", c.ID)
	return int(exitCode), nil
}

// Run implements the exec driver Driver interface
func (d *Driver) Run(c *execdriver.Command, pipes *execdriver.Pipes, hooks execdriver.Hooks) (execdriver.ExitStatus, error) {

	var (
		term execdriver.Terminal
		err  error
	)

	cu := &containerInit{
		SystemType:              "Container",
		Name:                    c.ID,
		Owner:                   defaultOwner,
		IsDummy:                 dummyMode,
		VolumePath:              c.Rootfs,
		IgnoreFlushesDuringBoot: c.FirstStart,
		LayerFolderPath:         c.LayerFolder,
		ProcessorWeight:         c.Resources.CPUShares,
		HostName:                c.Hostname,
	}

	cu.HvPartition = c.HvPartition

	if cu.HvPartition {
		cu.SandboxPath = filepath.Dir(c.LayerFolder)
	} else {
		cu.VolumePath = c.Rootfs
		cu.LayerFolderPath = c.LayerFolder
	}

	for _, layerPath := range c.LayerPaths {
		_, filename := filepath.Split(layerPath)
		g, err := hcsshim.NameToGuid(filename)
		if err != nil {
			return execdriver.ExitStatus{ExitCode: -1}, err
		}
		cu.Layers = append(cu.Layers, layer{
			ID:   g.ToString(),
			Path: layerPath,
		})
	}

	// Add the mounts (volumes, bind mounts etc) to the structure
	mds := make([]mappedDir, len(c.Mounts))
	for i, mount := range c.Mounts {
		mds[i] = mappedDir{
			HostPath:      mount.Source,
			ContainerPath: mount.Destination,
			ReadOnly:      !mount.Writable}
	}
	cu.MappedDirectories = mds

	// TODO Windows. At some point, when there is CLI on docker run to
	// enable the IP Address of the container to be passed into docker run,
	// the IP Address needs to be wired through to HCS in the JSON. It
	// would be present in c.Network.Interface.IPAddress. See matching
	// TODO in daemon\container_windows.go, function populateCommand.

	if c.Network.Interface != nil {

		var pbs []portBinding

		// Enumerate through the port bindings specified by the user and convert
		// them into the internal structure matching the JSON blob that can be
		// understood by the HCS.
		for i, v := range c.Network.Interface.PortBindings {
			proto := strings.ToUpper(i.Proto())
			if proto != "TCP" && proto != "UDP" {
				return execdriver.ExitStatus{ExitCode: -1}, fmt.Errorf("invalid protocol %s", i.Proto())
			}

			if len(v) > 1 {
				return execdriver.ExitStatus{ExitCode: -1}, fmt.Errorf("Windows does not support more than one host port in NAT settings")
			}

			for _, v2 := range v {
				var (
					iPort, ePort int
					err          error
				)
				if len(v2.HostIP) != 0 {
					return execdriver.ExitStatus{ExitCode: -1}, fmt.Errorf("Windows does not support host IP addresses in NAT settings")
				}
				if ePort, err = strconv.Atoi(v2.HostPort); err != nil {
					return execdriver.ExitStatus{ExitCode: -1}, fmt.Errorf("invalid container port %s: %s", v2.HostPort, err)
				}
				if iPort, err = strconv.Atoi(i.Port()); err != nil {
					return execdriver.ExitStatus{ExitCode: -1}, fmt.Errorf("invalid internal port %s: %s", i.Port(), err)
				}
				if iPort < 0 || iPort > 65535 || ePort < 0 || ePort > 65535 {
					return execdriver.ExitStatus{ExitCode: -1}, fmt.Errorf("specified NAT port is not in allowed range")
				}
				pbs = append(pbs,
					portBinding{ExternalPort: ePort,
						InternalPort: iPort,
						Protocol:     proto})
			}
		}

		// TODO Windows: TP3 workaround. Allow the user to override the name of
		// the Container NAT device through an environment variable. This will
//.........这里部分代码省略.........

// Run implements the exec driver Driver interface,
// it calls libcontainer APIs to run a container.
func (d *Driver) Run(c *execdriver.Command, pipes *execdriver.Pipes, hooks execdriver.Hooks) (execdriver.ExitStatus, error) {
	destroyed := false
	var err error
	c.TmpDir, err = ioutil.TempDir("", c.ID)
	if err != nil {
		return execdriver.ExitStatus{ExitCode: -1}, err
	}
	defer os.RemoveAll(c.TmpDir)

	// take the Command and populate the libcontainer.Config from it
	container, err := d.createContainer(c, hooks)
	if err != nil {
		return execdriver.ExitStatus{ExitCode: -1}, err
	}

	p := &libcontainer.Process{
		Args: append([]string{c.ProcessConfig.Entrypoint}, c.ProcessConfig.Arguments...),
		Env:  c.ProcessConfig.Env,
		Cwd:  c.WorkingDir,
		User: c.ProcessConfig.User,
	}

	wg := sync.WaitGroup{}
	writers, err := setupPipes(container, &c.ProcessConfig, p, pipes, &wg)
	if err != nil {
		return execdriver.ExitStatus{ExitCode: -1}, err
	}

	cont, err := d.factory.Create(c.ID, container)
	if err != nil {
		return execdriver.ExitStatus{ExitCode: -1}, err
	}
	d.Lock()
	d.activeContainers[c.ID] = cont
	d.Unlock()
	defer func() {
		if !destroyed {
			cont.Destroy()
		}
		d.cleanContainer(c.ID)
	}()

	if err := cont.Start(p); err != nil {
		return execdriver.ExitStatus{ExitCode: -1}, err
	}

	//close the write end of any opened pipes now that they are dup'ed into the container
	for _, writer := range writers {
		writer.Close()
	}
	// 'oom' is used to emit 'oom' events to the eventstream, 'oomKilled' is used
	// to set the 'OOMKilled' flag in state
	oom := notifyOnOOM(cont)
	oomKilled := notifyOnOOM(cont)
	if hooks.Start != nil {
		pid, err := p.Pid()
		if err != nil {
			p.Signal(os.Kill)
			p.Wait()
			return execdriver.ExitStatus{ExitCode: -1}, err
		}
		hooks.Start(&c.ProcessConfig, pid, oom)
	}

	waitF := p.Wait
	if nss := cont.Config().Namespaces; !nss.Contains(configs.NEWPID) {
		// we need such hack for tracking processes with inherited fds,
		// because cmd.Wait() waiting for all streams to be copied
		waitF = waitInPIDHost(p, cont)
	}
	ps, err := waitF()
	if err != nil {
		execErr, ok := err.(*exec.ExitError)
		if !ok {
			return execdriver.ExitStatus{ExitCode: -1}, err
		}
		ps = execErr.ProcessState
	}
	// wait for all IO goroutine copiers to finish
	wg.Wait()

	cont.Destroy()
	destroyed = true
	// oomKilled will have an oom event if any process within the container was
	// OOM killed at any time, not only if the init process OOMed.
	//
	// Perhaps we only want the OOMKilled flag to be set if the OOM
	// resulted in a container death, but there isn't a good way to do this
	// because the kernel's cgroup oom notification does not provide information
	// such as the PID. This could be heuristically done by checking that the OOM
	// happened within some very small time slice for the container dying (and
	// optionally exit-code 137), but I don't think the cgroup oom notification
	// can be used to reliably determine this
	//
	// Even if there were multiple OOMs, it's sufficient to read one value
	// because libcontainer's oom notify will discard the channel after the
	// cgroup is destroyed
	_, oomKill := <-oomKilled
//.........这里部分代码省略.........

// Exec implements the exec driver Driver interface.
func (d *Driver) Exec(c *execdriver.Command, processConfig *execdriver.ProcessConfig, pipes *execdriver.Pipes, hooks execdriver.Hooks) (int, error) {

	var (
		term     execdriver.Terminal
		err      error
		exitCode int32
		errno    uint32
	)

	active := d.activeContainers[c.ID]
	if active == nil {
		return -1, fmt.Errorf("Exec - No active container exists with ID %s", c.ID)
	}

	createProcessParms := hcsshim.CreateProcessParams{
		EmulateConsole:   processConfig.Tty, // Note NOT c.ProcessConfig.Tty
		WorkingDirectory: c.WorkingDir,
	}

	// Configure the environment for the process // Note NOT c.ProcessConfig.Tty
	createProcessParms.Environment = setupEnvironmentVariables(processConfig.Env)

	// While this should get caught earlier, just in case, validate that we
	// have something to run.
	if processConfig.Entrypoint == "" {
		err = errors.New("No entrypoint specified")
		logrus.Error(err)
		return -1, err
	}

	// Build the command line of the process
	createProcessParms.CommandLine = processConfig.Entrypoint
	for _, arg := range processConfig.Arguments {
		logrus.Debugln("appending ", arg)
		createProcessParms.CommandLine += " " + arg
	}
	logrus.Debugln("commandLine: ", createProcessParms.CommandLine)

	// Start the command running in the container.
	pid, stdin, stdout, stderr, err := hcsshim.CreateProcessInComputeSystem(c.ID, pipes.Stdin != nil, true, !processConfig.Tty, createProcessParms)
	if err != nil {
		logrus.Errorf("CreateProcessInComputeSystem() failed %s", err)
		return -1, err
	}

	// Now that the process has been launched, begin copying data to and from
	// the named pipes for the std handles.
	setupPipes(stdin, stdout, stderr, pipes)

	// Note NOT c.ProcessConfig.Tty
	if processConfig.Tty {
		term = NewTtyConsole(c.ID, pid)
	} else {
		term = NewStdConsole()
	}
	processConfig.Terminal = term

	// Invoke the start callback
	if hooks.Start != nil {
		// A closed channel for OOM is returned here as it will be
		// non-blocking and return the correct result when read.
		chOOM := make(chan struct{})
		close(chOOM)
		hooks.Start(&c.ProcessConfig, int(pid), chOOM)
	}

	if exitCode, errno, err = hcsshim.WaitForProcessInComputeSystem(c.ID, pid, hcsshim.TimeoutInfinite); err != nil {
		if errno == hcsshim.Win32PipeHasBeenEnded {
			logrus.Debugf("Exiting Run() after WaitForProcessInComputeSystem failed with recognised error 0x%X", errno)
			return hcsshim.WaitErrExecFailed, nil
		}
		logrus.Warnf("WaitForProcessInComputeSystem failed (container may have been killed): 0x%X %s", errno, err)
		return -1, err
	}

	logrus.Debugln("Exiting Run()", c.ID)
	return int(exitCode), nil
}

// Run implements the exec driver Driver interface
func (d *Driver) Run(c *execdriver.Command, pipes *execdriver.Pipes, hooks execdriver.Hooks) (execdriver.ExitStatus, error) {

	var (
		term execdriver.Terminal
		err  error
	)

	// Make sure the client isn't asking for options which aren't supported
	err = checkSupportedOptions(c)
	if err != nil {
		return execdriver.ExitStatus{ExitCode: -1}, err
	}

	cu := &containerInit{
		SystemType:              "Container",
		Name:                    c.ID,
		Owner:                   defaultOwner,
		IsDummy:                 dummyMode,
		VolumePath:              c.Rootfs,
		IgnoreFlushesDuringBoot: c.FirstStart,
		LayerFolderPath:         c.LayerFolder,
	}

	for i := 0; i < len(c.LayerPaths); i++ {
		_, filename := filepath.Split(c.LayerPaths[i])
		g, err := hcsshim.NameToGuid(filename)
		if err != nil {
			return execdriver.ExitStatus{ExitCode: -1}, err
		}
		cu.Layers = append(cu.Layers, layer{
			ID:   g.ToString(),
			Path: c.LayerPaths[i],
		})
	}

	// TODO Windows. At some point, when there is CLI on docker run to
	// enable the IP Address of the container to be passed into docker run,
	// the IP Address needs to be wired through to HCS in the JSON. It
	// would be present in c.Network.Interface.IPAddress. See matching
	// TODO in daemon\container_windows.go, function populateCommand.

	if c.Network.Interface != nil {

		var pbs []portBinding

		// Enumerate through the port bindings specified by the user and convert
		// them into the internal structure matching the JSON blob that can be
		// understood by the HCS.
		for i, v := range c.Network.Interface.PortBindings {
			proto := strings.ToUpper(i.Proto())
			if proto != "TCP" && proto != "UDP" {
				return execdriver.ExitStatus{ExitCode: -1}, fmt.Errorf("invalid protocol %s", i.Proto())
			}

			if len(v) > 1 {
				return execdriver.ExitStatus{ExitCode: -1}, fmt.Errorf("Windows does not support more than one host port in NAT settings")
			}

			for _, v2 := range v {
				var (
					iPort, ePort int
					err          error
				)
				if len(v2.HostIP) != 0 {
					return execdriver.ExitStatus{ExitCode: -1}, fmt.Errorf("Windows does not support host IP addresses in NAT settings")
				}
				if ePort, err = strconv.Atoi(v2.HostPort); err != nil {
					return execdriver.ExitStatus{ExitCode: -1}, fmt.Errorf("invalid container port %s: %s", v2.HostPort, err)
				}
				if iPort, err = strconv.Atoi(i.Port()); err != nil {
					return execdriver.ExitStatus{ExitCode: -1}, fmt.Errorf("invalid internal port %s: %s", i.Port(), err)
				}
				if iPort < 0 || iPort > 65535 || ePort < 0 || ePort > 65535 {
					return execdriver.ExitStatus{ExitCode: -1}, fmt.Errorf("specified NAT port is not in allowed range")
				}
				pbs = append(pbs,
					portBinding{ExternalPort: ePort,
						InternalPort: iPort,
						Protocol:     proto})
			}
		}

		// TODO Windows: TP3 workaround. Allow the user to override the name of
		// the Container NAT device through an environment variable. This will
		// ultimately be a global daemon parameter on Windows, similar to -b
		// for the name of the virtual switch (aka bridge).
		cn := os.Getenv("DOCKER_CONTAINER_NAT")
		if len(cn) == 0 {
			cn = defaultContainerNAT
		}

		dev := device{
			DeviceType: "Network",
			Connection: &networkConnection{
				NetworkName: c.Network.Interface.Bridge,
				// TODO Windows: Fixme, next line. Needs HCS fix.
				EnableNat: false,
				Nat: natSettings{
					Name:         cn,
//.........这里部分代码省略.........

//.........这里部分代码省略.........

	if d.sharedRoot {
		// lxc-start really needs / to be non-shared, or all kinds of stuff break
		// when lxc-start unmount things and those unmounts propagate to the main
		// mount namespace.
		// What we really want is to clone into a new namespace and then
		// mount / MS_REC|MS_SLAVE, but since we can't really clone or fork
		// without exec in go we have to do this horrible shell hack...
		shellString :=
			"mount --make-rslave /; exec " +
				stringutils.ShellQuoteArguments(params)

		params = []string{
			"unshare", "-m", "--", "/bin/sh", "-c", shellString,
		}
	}
	logrus.Debugf("lxc params %s", params)
	var (
		name = params[0]
		arg  = params[1:]
	)
	aname, err := exec.LookPath(name)
	if err != nil {
		aname = name
	}
	c.ProcessConfig.Path = aname
	c.ProcessConfig.Args = append([]string{name}, arg...)

	if err := createDeviceNodes(c.Rootfs, c.AutoCreatedDevices); err != nil {
		killNetNsProc(proc)
		return execdriver.ExitStatus{ExitCode: -1}, err
	}

	if err := c.ProcessConfig.Start(); err != nil {
		killNetNsProc(proc)
		return execdriver.ExitStatus{ExitCode: -1}, err
	}

	var (
		waitErr  error
		waitLock = make(chan struct{})
	)

	go func() {
		if err := c.ProcessConfig.Wait(); err != nil {
			if _, ok := err.(*exec.ExitError); !ok { // Do not propagate the error if it's simply a status code != 0
				waitErr = err
			}
		}
		close(waitLock)
	}()

	terminate := func(terr error) (execdriver.ExitStatus, error) {
		if c.ProcessConfig.Process != nil {
			c.ProcessConfig.Process.Kill()
			c.ProcessConfig.Wait()
		}
		return execdriver.ExitStatus{ExitCode: -1}, terr
	}
	// Poll lxc for RUNNING status
	pid, err := d.waitForStart(c, waitLock)
	if err != nil {
		killNetNsProc(proc)
		return terminate(err)
	}
	killNetNsProc(proc)

// Exec implements the exec driver Driver interface,
// it calls libcontainer APIs to execute a container.
func (d *Driver) Exec(c *execdriver.Command, processConfig *execdriver.ProcessConfig, pipes *execdriver.Pipes, hooks execdriver.Hooks) (int, error) {
	active := d.activeContainers[c.ID]
	if active == nil {
		return -1, fmt.Errorf("No active container exists with ID %s", c.ID)
	}

	user := processConfig.User
	if c.RemappedRoot.UID != 0 && user == "" {
		//if user namespaces are enabled, set user explicitly so uid/gid is set to 0
		//otherwise we end up with the overflow id and no permissions (65534)
		user = "0"
	}

	p := &libcontainer.Process{
		Args: append([]string{processConfig.Entrypoint}, processConfig.Arguments...),
		Env:  c.ProcessConfig.Env,
		Cwd:  c.WorkingDir,
		User: user,
	}

	if processConfig.Privileged {
		p.Capabilities = execdriver.GetAllCapabilities()
	}
	// add CAP_ prefix to all caps for new libcontainer update to match
	// the spec format.
	for i, s := range p.Capabilities {
		if !strings.HasPrefix(s, "CAP_") {
			p.Capabilities[i] = fmt.Sprintf("CAP_%s", s)
		}
	}

	config := active.Config()
	wg := sync.WaitGroup{}
	writers, err := setupPipes(&config, processConfig, p, pipes, &wg)
	if err != nil {
		return -1, err
	}

	if err := active.Start(p); err != nil {
		return -1, err
	}
	//close the write end of any opened pipes now that they are dup'ed into the container
	for _, writer := range writers {
		writer.Close()
	}

	if hooks.Start != nil {
		pid, err := p.Pid()
		if err != nil {
			p.Signal(os.Kill)
			p.Wait()
			return -1, err
		}

		// A closed channel for OOM is returned here as it will be
		// non-blocking and return the correct result when read.
		chOOM := make(chan struct{})
		close(chOOM)
		hooks.Start(&c.ProcessConfig, pid, chOOM)
	}

	ps, err := p.Wait()
	if err != nil {
		exitErr, ok := err.(*exec.ExitError)
		if !ok {
			return -1, err
		}
		ps = exitErr.ProcessState
	}
	// wait for all IO goroutine copiers to finish
	wg.Wait()
	return utils.ExitStatus(ps.Sys().(syscall.WaitStatus)), nil
}