/
driver.go
547 lines (489 loc) · 13.3 KB
/
driver.go
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// +build linux,cgo
package native
import (
"fmt"
"io"
"os"
"os/exec"
"path/filepath"
"strings"
"sync"
"syscall"
"time"
"github.com/Sirupsen/logrus"
"github.com/docker/docker/daemon/execdriver"
"github.com/docker/docker/pkg/parsers"
"github.com/docker/docker/pkg/pools"
"github.com/docker/docker/pkg/reexec"
sysinfo "github.com/docker/docker/pkg/system"
"github.com/docker/docker/pkg/term"
"github.com/opencontainers/runc/libcontainer"
"github.com/opencontainers/runc/libcontainer/apparmor"
"github.com/opencontainers/runc/libcontainer/cgroups/systemd"
"github.com/opencontainers/runc/libcontainer/configs"
"github.com/opencontainers/runc/libcontainer/system"
"github.com/opencontainers/runc/libcontainer/utils"
)
// Define constants for native driver
const (
DriverName = "native"
Version = "0.2"
)
// Driver contains all information for native driver,
// it implements execdriver.Driver.
type Driver struct {
root string
initPath string
activeContainers map[string]libcontainer.Container
machineMemory int64
factory libcontainer.Factory
sync.Mutex
}
// NewDriver returns a new native driver, called from NewDriver of execdriver.
func NewDriver(root, initPath string, options []string) (*Driver, error) {
meminfo, err := sysinfo.ReadMemInfo()
if err != nil {
return nil, err
}
if err := sysinfo.MkdirAll(root, 0700); err != nil {
return nil, err
}
if apparmor.IsEnabled() {
if err := installAppArmorProfile(); err != nil {
apparmorProfiles := []string{"docker-default"}
// Allow daemon to run if loading failed, but are active
// (possibly through another run, manually, or via system startup)
for _, policy := range apparmorProfiles {
if err := hasAppArmorProfileLoaded(policy); err != nil {
return nil, fmt.Errorf("AppArmor enabled on system but the %s profile could not be loaded.", policy)
}
}
}
}
// choose cgroup manager
// this makes sure there are no breaking changes to people
// who upgrade from versions without native.cgroupdriver opt
cgm := libcontainer.Cgroupfs
if systemd.UseSystemd() {
cgm = libcontainer.SystemdCgroups
}
// parse the options
for _, option := range options {
key, val, err := parsers.ParseKeyValueOpt(option)
if err != nil {
return nil, err
}
key = strings.ToLower(key)
switch key {
case "native.cgroupdriver":
// override the default if they set options
switch val {
case "systemd":
if systemd.UseSystemd() {
cgm = libcontainer.SystemdCgroups
} else {
// warn them that they chose the wrong driver
logrus.Warn("You cannot use systemd as native.cgroupdriver, using cgroupfs instead")
}
case "cgroupfs":
cgm = libcontainer.Cgroupfs
default:
return nil, fmt.Errorf("Unknown native.cgroupdriver given %q. try cgroupfs or systemd", val)
}
default:
return nil, fmt.Errorf("Unknown option %s\n", key)
}
}
f, err := libcontainer.New(
root,
cgm,
libcontainer.InitPath(reexec.Self(), DriverName),
)
if err != nil {
return nil, err
}
return &Driver{
root: root,
initPath: initPath,
activeContainers: make(map[string]libcontainer.Container),
machineMemory: meminfo.MemTotal,
factory: f,
}, nil
}
type execOutput struct {
exitCode int
err error
}
// 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
// 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() {
if !destroyed {
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()
destroyed = true
_, oomKill := <-oom
return execdriver.ExitStatus{ExitCode: utils.ExitStatus(ps.Sys().(syscall.WaitStatus)), OOMKilled: oomKill}, nil
}
// notifyOnOOM returns a channel that signals if the container received an OOM notification
// for any process. If it is unable to subscribe to OOM notifications then a closed
// channel is returned as it will be non-blocking and return the correct result when read.
func notifyOnOOM(container libcontainer.Container) <-chan struct{} {
oom, err := container.NotifyOOM()
if err != nil {
logrus.Warnf("Your kernel does not support OOM notifications: %s", err)
c := make(chan struct{})
close(c)
return c
}
return oom
}
func killCgroupProcs(c libcontainer.Container) {
var procs []*os.Process
if err := c.Pause(); err != nil {
logrus.Warn(err)
}
pids, err := c.Processes()
if err != nil {
// don't care about childs if we can't get them, this is mostly because cgroup already deleted
logrus.Warnf("Failed to get processes from container %s: %v", c.ID(), err)
}
for _, pid := range pids {
if p, err := os.FindProcess(pid); err == nil {
procs = append(procs, p)
if err := p.Kill(); err != nil {
logrus.Warn(err)
}
}
}
if err := c.Resume(); err != nil {
logrus.Warn(err)
}
for _, p := range procs {
if _, err := p.Wait(); err != nil {
logrus.Warn(err)
}
}
}
func waitInPIDHost(p *libcontainer.Process, c libcontainer.Container) func() (*os.ProcessState, error) {
return func() (*os.ProcessState, error) {
pid, err := p.Pid()
if err != nil {
return nil, err
}
process, err := os.FindProcess(pid)
s, err := process.Wait()
if err != nil {
execErr, ok := err.(*exec.ExitError)
if !ok {
return s, err
}
s = execErr.ProcessState
}
killCgroupProcs(c)
p.Wait()
return s, err
}
}
// Kill implements the exec driver Driver interface.
func (d *Driver) Kill(c *execdriver.Command, sig int) error {
d.Lock()
active := d.activeContainers[c.ID]
d.Unlock()
if active == nil {
return fmt.Errorf("active container for %s does not exist", c.ID)
}
state, err := active.State()
if err != nil {
return err
}
return syscall.Kill(state.InitProcessPid, syscall.Signal(sig))
}
// Pause implements the exec driver Driver interface,
// it calls libcontainer API to pause a container.
func (d *Driver) Pause(c *execdriver.Command) error {
d.Lock()
active := d.activeContainers[c.ID]
d.Unlock()
if active == nil {
return fmt.Errorf("active container for %s does not exist", c.ID)
}
return active.Pause()
}
// Unpause implements the exec driver Driver interface,
// it calls libcontainer API to unpause a container.
func (d *Driver) Unpause(c *execdriver.Command) error {
d.Lock()
active := d.activeContainers[c.ID]
d.Unlock()
if active == nil {
return fmt.Errorf("active container for %s does not exist", c.ID)
}
return active.Resume()
}
// Terminate implements the exec driver Driver interface.
func (d *Driver) Terminate(c *execdriver.Command) error {
defer d.cleanContainer(c.ID)
container, err := d.factory.Load(c.ID)
if err != nil {
return err
}
defer container.Destroy()
state, err := container.State()
if err != nil {
return err
}
pid := state.InitProcessPid
currentStartTime, err := system.GetProcessStartTime(pid)
if err != nil {
return err
}
if state.InitProcessStartTime == currentStartTime {
err = syscall.Kill(pid, 9)
syscall.Wait4(pid, nil, 0, nil)
}
return err
}
// Info implements the exec driver Driver interface.
func (d *Driver) Info(id string) execdriver.Info {
return &info{
ID: id,
driver: d,
}
}
// Name implements the exec driver Driver interface.
func (d *Driver) Name() string {
return fmt.Sprintf("%s-%s", DriverName, Version)
}
// GetPidsForContainer implements the exec driver Driver interface.
func (d *Driver) GetPidsForContainer(id string) ([]int, error) {
d.Lock()
active := d.activeContainers[id]
d.Unlock()
if active == nil {
return nil, fmt.Errorf("active container for %s does not exist", id)
}
return active.Processes()
}
func (d *Driver) cleanContainer(id string) error {
d.Lock()
delete(d.activeContainers, id)
d.Unlock()
return os.RemoveAll(filepath.Join(d.root, id))
}
func (d *Driver) createContainerRoot(id string) error {
return os.MkdirAll(filepath.Join(d.root, id), 0655)
}
// Clean implements the exec driver Driver interface.
func (d *Driver) Clean(id string) error {
return os.RemoveAll(filepath.Join(d.root, id))
}
// Stats implements the exec driver Driver interface.
func (d *Driver) Stats(id string) (*execdriver.ResourceStats, error) {
d.Lock()
c := d.activeContainers[id]
d.Unlock()
if c == nil {
return nil, execdriver.ErrNotRunning
}
now := time.Now()
stats, err := c.Stats()
if err != nil {
return nil, err
}
memoryLimit := c.Config().Cgroups.Memory
// if the container does not have any memory limit specified set the
// limit to the machines memory
if memoryLimit == 0 {
memoryLimit = d.machineMemory
}
return &execdriver.ResourceStats{
Stats: stats,
Read: now,
MemoryLimit: memoryLimit,
}, nil
}
// TtyConsole implements the exec driver Terminal interface.
type TtyConsole struct {
console libcontainer.Console
}
// NewTtyConsole returns a new TtyConsole struct.
func NewTtyConsole(console libcontainer.Console, pipes *execdriver.Pipes) (*TtyConsole, error) {
tty := &TtyConsole{
console: console,
}
if err := tty.AttachPipes(pipes); err != nil {
tty.Close()
return nil, err
}
return tty, nil
}
// Resize implements Resize method of Terminal interface
func (t *TtyConsole) Resize(h, w int) error {
return term.SetWinsize(t.console.Fd(), &term.Winsize{Height: uint16(h), Width: uint16(w)})
}
// AttachPipes attaches given pipes to TtyConsole
func (t *TtyConsole) AttachPipes(pipes *execdriver.Pipes) error {
go func() {
if wb, ok := pipes.Stdout.(interface {
CloseWriters() error
}); ok {
defer wb.CloseWriters()
}
pools.Copy(pipes.Stdout, t.console)
}()
if pipes.Stdin != nil {
go func() {
pools.Copy(t.console, pipes.Stdin)
pipes.Stdin.Close()
}()
}
return nil
}
// Close implements Close method of Terminal interface
func (t *TtyConsole) Close() error {
return t.console.Close()
}
func setupPipes(container *configs.Config, processConfig *execdriver.ProcessConfig, p *libcontainer.Process, pipes *execdriver.Pipes) error {
rootuid, err := container.HostUID()
if err != nil {
return err
}
if processConfig.Tty {
cons, err := p.NewConsole(rootuid)
if err != nil {
return err
}
term, err := NewTtyConsole(cons, pipes)
if err != nil {
return err
}
processConfig.Terminal = term
return nil
}
// not a tty--set up stdio pipes
term := &execdriver.StdConsole{}
processConfig.Terminal = term
// if we are not in a user namespace, there is no reason to go through
// the hassle of setting up os-level pipes with proper (remapped) ownership
// so we will do the prior shortcut for non-userns containers
if rootuid == 0 {
p.Stdout = pipes.Stdout
p.Stderr = pipes.Stderr
r, w, err := os.Pipe()
if err != nil {
return err
}
if pipes.Stdin != nil {
go func() {
io.Copy(w, pipes.Stdin)
w.Close()
}()
p.Stdin = r
}
return nil
}
// if we have user namespaces enabled (rootuid != 0), we will set
// up os pipes for stderr, stdout, stdin so we can chown them to
// the proper ownership to allow for proper access to the underlying
// fds
var fds []int
//setup stdout
r, w, err := os.Pipe()
if err != nil {
return err
}
fds = append(fds, int(r.Fd()), int(w.Fd()))
if pipes.Stdout != nil {
go io.Copy(pipes.Stdout, r)
}
term.Closers = append(term.Closers, r)
p.Stdout = w
//setup stderr
r, w, err = os.Pipe()
if err != nil {
return err
}
fds = append(fds, int(r.Fd()), int(w.Fd()))
if pipes.Stderr != nil {
go io.Copy(pipes.Stderr, r)
}
term.Closers = append(term.Closers, r)
p.Stderr = w
//setup stdin
r, w, err = os.Pipe()
if err != nil {
return err
}
fds = append(fds, int(r.Fd()), int(w.Fd()))
if pipes.Stdin != nil {
go func() {
io.Copy(w, pipes.Stdin)
w.Close()
}()
p.Stdin = r
}
for _, fd := range fds {
if err := syscall.Fchown(fd, rootuid, rootuid); err != nil {
return fmt.Errorf("Failed to chown pipes fd: %v", err)
}
}
return nil
}
// SupportsHooks implements the execdriver Driver interface.
// The libcontainer/runC-based native execdriver does exploit the hook mechanism
func (d *Driver) SupportsHooks() bool {
return true
}